welding and materials-at a glance06,07,2013

MATERIALS AND

WELDING For Engineers AT A GLANCE

ART IN STEAM CO.

HRSG BOILER EXPERTS

WWW.ARTINSTEAM.COM MAY-JUNE 2013

The main purpose for preparing this free magazine is to summarize the most

famous and leading welding magazines .

We believe these article are proper for designers, engineers and inspectors in

oil, gas and power .

In the following issue we have articles from :

1-Practical welding-The official publication of fabricators and manufacturers

association

2-AMP The ASM journal of advanced material processing

3- Inspection trends-The AWS inspection and testing journal

4-The welding Journal-AWS welding and material journal

5-The Fabricator- The official publication of fabricators and manufacturers

association

There are also other several important magazine in materials and welding

such as :Connect-TWI magazine, Paton welding journal, Welding news ...

Which we try to have some articles from in the future.

Sincerely yours

Art In Steam co. Manager

An official publication of the Fabricators & Manufacturers Association, International

www.practicalwelding.com

May/June 2013

THE REAL WORLD FOR WELDING PROFESSIONALS

GMAW guns: The right one makes

all the difference

GMAW guns: The right one makes

all the difference

MayJune13PWT.indd 1 4/25/13 3:23 PM

www.practicalwelding.comPRACTICAL WELDING TODAY May/June 20138

By Amanda Carlson, Associate Editor

As a former consultant and robotic welding shop owner, Mark Satka, product engineer at Innovative Product Ideas LLC, Neenah, Wis., has seen fi rsthand the cre-ative ways welders clean away spatter around the welded sur-face. Hes seen them use everything from scrap metal to chis-els, screwdrivers, and homemade tools, and it always struck him as odd that there wasnt a dedicated tool for the job.

Spatter is an unwelcome yet very common side effect of many welding applications. To combat this, welders usually take matters into their own hands.

None of the weld shops I visited as a consultant had a specifi c tool for removing the postweld spatter. A lot of people had their own homemade chisels or screwdrivers to remove spatter, but there was nothing specifi cally made for the spatter removal process, Satka explained.

And with welders using whatever means necessary to re-move the spatter, leaving the base material vulnerable to scratches and surface marring, Satka believed there was a bet-ter way. This realization is what led him down the path to developing a tool designed specifi cally for postweld and cut surface cleaning that was durable enough to remove tough spatter from the areas surrounding a weld, dross from thermal cutting operations, or slag, but forgiving enough not to dam-age the base material.

Its been a journey thats been 10 years in the undertak-ing, but after much research and development that went into designing the product and procuring the right blade mate-rial, the Scrap-N-Burr was fi nally unveiled last November at FABTECH in Las Vegas.

The concept is simple, but the pathway to the end product was anything but, said Tim Houselog, president of Innovative Prod-uct Ideas, the manufacturer of the tool. For the most part it revolves around the propri-etary high-strength steel used for the blade.

It was important to de-velop something that would remove spatter without mar-ring the parent material, while at the same time ensuring the blade would maintain its dual working edges so welders werent constantly tasked with sharpening the blade with a grinding wheel, Houselog said.

The company has focused much of its efforts for the last four years on the blade confi g-uration, Satka added. Blades are equipped with DuaLast

technology, which Houselog said stands for dual edge long lasting. They are designed to be durable enough to withstand the harsh conditions of spatter removal and edge deburring.

Blade size and confi guration was another aspect that the company worked on to accommodate as many applications as possible

A lot of places say they wish they had a wider blade or a narrower blade. One of the features weve included is the blade widths are interchangeable, Satka explained.

Flat blades are available in 1-, 3-, and 4-in. sizes. The company recently released blades specifi cally designed for tube applications. Six blades are available starting at 34 in. and in-creasing in quarter-inch increments up to 2-in.-dia. tubing.

A -in. hole drilled into the side of the scraper accepts any -in. shank accessory or wire brush. This is important for welders who are using fl ux-core or rodany application in which slag is left over. They can chip the slag off with the blade and then use the wire brush over the top of it.

The -in. shank leaves it up to your imagination. People sometimes come up with things to put in there that you would

Technology Spotlight

Get your scrape onNew hand tool dedicated for slag, spatter, and dross removal

New to the Scrape-N-Burr family are the six blades dedicated for tube cleaning applications.

Welders have a choice of three fl at blades in 112-, 3-, and 412-in. sizes.

MayJune13PWT.indd 8 4/26/13 11:57 AM

www.practicalwelding.com May/June 2013 PRACTICAL WELDING TODAY 9

never think possible. If it works for them and what theyre do-ing, thats all that counts, Houselog explained.

The handle has a cushioned grip for comfort and a striking surface on the back so welders can use it as a chisel or hammer during diffi cult cleanup applications. Depending on the blade size, the tool weighs around 1 pound.

If the standard version of the tool does not suit a welders needs, the company can design a specialty blade or handle to accommodate the application.

We did a special run for Caterpillar for an application where they were pushing through extremely large weldments. We specially made them a tool with a 3-ft. handle instead of the standard 11 in. We were able to turn around a version of the product really quickly that would work great for them. They love them, Houselog said.

Scrape-N-Burr, 866-895-1531, www.scrapenburr.com

Abicor Binzel www.abicorusa.comAbirob A500 air-cooled torch heat reduction

SITUATION: Flex-N-Gate is a leading Tier One manu-facturer of high quality, stamped metal components and complex assemblies, supplying over 84% of metal bumper systems for trucks and SUVs in North America. This facility was experiencing heat related issues and high consumable usage (nozzles, diffusers, and contact tips). The excessive heat was also causing distortion of swannecks and fre-quent re-teaching of weld points in robot programs.

RESOLUTION: The Abirob A500 amp air-cooled torch package was tested in a dual robot cell that was hav-ing the most issues. This cell was chosen to do head to head comparison against the current welding torch and document results. The Abirob A500 amp thru arm torch package was installed in less than 2 hours and the testing began. A thermal imaging camera was used to look at the heat difference between the ABICOR Binzel swanneck and safety clutch versus the current brand.

Photos were taken immediately after a steady produc-tion run. Weld settings are 18-21 volts, 200 amps, pulse mode. As you can see from the photos the Abirob A500 product ran considerably cooler than the other torch, es-pecially in the safety clutch that resulted in the swanneck

staying cooler and consumables lasting longer. The Abi-rob welding package resulted in longer consumable life and considerably less downtime related to the better heat dissipation from the swanneck. Scott Abernathy of Flex-N-Gates MasterGuard production liked the ease of instal-lation and, Overall, a more robust system than what we were previously using.

Converting to the ABICOR Binzel product has resulted in less overall cost of consumable usage and less down-time resulting in higher throughput of parts.

Advertorial

The dual-edge blade is tough enough to remove spatter and slag without damaging the parent material.

MayJune13PWT.indd 9 4/26/13 11:55 AM

PRACTICAL WELDING TODAY May/June 201318

Cover Story

8criteria for choosing the right GMAW gunApplication requirements and operator preference are keyA gun that matches your personal preferences helps if you weld in diffi cult positions often.

www.practicalwelding.com18 PRACTICAL WELDING TODAY May/June 2013


May/June 2013 PRACTICAL WELDING TODAY 19www.practicalwelding.com

By Ross Fleischmann

Even the most experienced and tal-ented welding operator requires the right tools to do the job well. To optimize weld quality, its important to carefully select all the tools involved, from the welding power source to the accessories. For gas metal arc welding (GMAW), the right gun can be criti-cal in ensuring an efficient and properly functioning system.

With so many guns available, it may be confusing to know which is the best option. A determining factor is whether youll need the gun for one specific ap-plication with fairly consistent param-eters or for a variety of projects. If you plan to use the gun for more than one welding application, you may want to consider a model with a wide range of abilities.

At the heart of your decision should be comfort. Gun weight, heat dissipa-tion, shape, hand positioning, and trig-ger configuration all contribute to your experience. Although you may purchase welding guns based solely on cost and basic application needs, your personal preferences should also be taken into consideration. These eight criteria will help you in your journey to select the GMAW gun that is right for you and your welding operation.

1Wire Size and TypeThe welding wire type and size you use will dictate certain features your GMAW gun will need. Aluminum wire requires a gun with a Teflon liner, while solid or cored mild and stainless steel wires need a gun with a liner made from pia-no wire a tempered, high-carbon steel also known as music wire or spring steel.

Its also important to match the liner diameter and gun tip with the wire di-ameter. If a liner is not sized properly for the wire, it can create resistance and the wire wont feed smoothly and pos-sibly create a birds nest. If the liner is too large, the wire can snakemove in a serpentine motioninside the liner and feed erratically. As a rule, use the correct liner size. With that said, you can get by with a liner thats one size larger than the diameter of wire being used. For ex-ample, an 0.045-in.- dia. flux-cored wire will perform just fine in an 0.052-in.-dia. liner.

2Amperage and Duty CycleThe arc-on time for a job has a signifi-cant impact on the guns amperage and duty cycle ratings. For applications that require a lot of arc-on time, the gun must be rated for higher duty cycle to meet those requirements. For jobs with

A paddle-shaped gun handle, like the one shown, reduces stress on your hand.


www.practicalwelding.com

low arc-on time, youre making short welds, or you spend time on setup or cleaning between welds, a gun with a lower rating may be appropriate.

Duty cycle defines how long the ma-chine can be used before work must be stopped to let the gun cool down. Duty cycle ratings are expressed as a percent-age of a 10-minute period. If a gun is rated at 60 percent duty cycle at 400

amps, it can be used to weld for up to 6 minutes at 400 amps before needing a cool-off period of 4 minutes. Unlike most power supplies in which a thermal overload will shut them down, guns have no protective fuses and can operate beyond their duty cycle. When guns op-erate at amperages other than the ones stated, their corresponding duty cycle goes up or down accordingly.

If you use the gun longer than its duty cycle rating, it becomes overheated and uncomfortable to use. Repeated overheating can damage a gun. In some cases, it may be more cost-effective and convenient to choose a higher-amperage gun to use for many applications instead of having multiple guns to change out throughout the day.

Guns are available in air-cooled and water-cooled models. Most air-cooled guns use a coaxial design. As amperage rating increases for air-cooled guns, the cables become larger and the guns be-come heavier, making them more diffi-cult to maneuver.

Water-cooled guns have water lines that run through the cable indepen-dent from the liner. They have smaller handles and smaller cables, so they are lighter-weight. So in applications with longer arc-on times at 400 amps or more, a lighter water-cooled gun can reduce fatigue and improve maneuver-ability. Although a water-cooled gun may cost more upfront, it can improve productivity. Water-cooled guns also keep consumables cooler, which extends parts life. The downside is that they cost more, can leak water, and have more maintenance requirements.

3Shielding GasShielding gases can have an effect on the duty cycle of a GMAW gun. For ex-ample, an argon/oxygen or argon/CO

2

mixture used for spray-transfer weld-ing will produce more heat than a gas-shielded flux-cored wire process using CO

2. Consider choosing a gun with a

slightly higher rating if you weld with argon blends. For example, if a proce-dure calls for spray-transfer welding at 350 amps, select a 400-amp gun.

PRACTICAL WELDING TODAY May/June 201320

Dont be tempted to remove the strain relief steel springs to improve maneuverability; doing so risks wire feeding problems.



4Cable LengthApplications involving large weldments may require long gun cables. When choosing a gun, its best to select the shortest gun cable necessary. As cables get longer, there is more opportunity for friction in the line, which can affect feed-ability of the wire in push-style guns.

Wire size and type can help you de-termine the best cable length. Wire that is 0.035 in. and smaller is very difficult to push through gun cables longer than 12 ft. Larger wire, such as a 0.052- or 116-in. dia., is easier to push through 15- or 20-ft. cable. If the required lead length causes feeding problems, try mounting the wire feeder on a boom or pole above the work area.

For extraordinary circumstances when using solid or cored wires and for aluminum applications, consider using a push/pull gun. These guns have two sets of drive rollsone at the feeder and one at the gun. The drive rolls work in conjunction with one another to main-tain consistent wire tension and ensure smooth feeding performance at distanc-es up to 35 ft.

5Cable Strain ReliefIf the bend radius of the cable becomes strained at the handle, it can cause kinked wire and poor feedability. Guns with steel springs at the handle will im-pose less strain on the lining, which can be especially important in applications

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with tight spaces or overhead-mounted wire feeders. Although you might be tempted to remove the spring to improve ma-neuverability in small areas, doing so could create feedability problems.

6Conductor TubeMost standard GMAW guns have a short conductor tubecommonly called a gooseneckbecause its closer to the work and it gives you more control. Longer conductor tubes offer larger radiuses and are available in different shapes to allow for better access in special applications. In some cases, GMAW equipment manufacturers can custom-design conductor tubes that meet the configurations for unique applications.

Longer conductor tubes are often used for duty cycle appli-cations that are 450 amps or more because it keeps your hands far away from the arcs heat. Flexible conductor tubes can be used on jobs that have issues related to joint access.


PRACTICAL WELDING TODAY 23

7ConsumablesMany consumables are available that can enhance the productivity of any gun. Be sure to choose a contact tip based on the amperage, duty cycle, and wire diameter of your application. Contact tips are available recessed, flush, or protruding from the nozzle.

A protruding tip gives you better visi-bility of the arc. Flush tips often are used for lower-duty-cycle, lower-amperage welding and pulsed GMAW. Recessed tips offer a greater arc-to-work distance and reduce spatter when using 100 per-cent CO

2. Spot nozzles have crowns cut

out of the nozzle to relieve gas pressure for spot welding. Gasless flux-cored tip assemblies effectively dont have a nozzle because gasless flux-cored wire doesnt require shielding gas.

8Handle and TriggerGMAW gun handles come in differ-ent styles, so you need to determine which one is most comfortable in the position your application dictates. Some gun handles have a round cross section, much like a broomstick handle. Other guns have a paddle-shaped cross section, which gives you more leverage to ma-neuver the gun cable. Many operators report that a paddle-shaped handle also reduces hand fatigue, particularly in ap-plications where they need to twist the gun cable to get correct alignment.

Before choosing a gun, consider your preferred hand positioningdo you grip

the gun like a pistol with the index finger on the trigger, or do you hold it upside down with your thumb on the trigger? Make sure the gun you are considering accommodates your preferred grip style.

More modern guns have longer trig-gers that allow you to move along the length of the handle for repositioning. This ability to change hand position helps reduce muscle fatigue and repeti-

tive-motion injury. To enhance comfort further in applications with high arc-on time, a dual-schedule trigger will lock in the on position like a toggle until you press it again. n

Ross Fleischmann is senior brand manager, Victor Technologies, 16052 Swingley Ridge Road, Suite 300, St. Louis, MO 63017, 800-426-1888, www.victortechnologies.com.



Aluminum vessels are steadily making their way into the U.S. Navy fleet. While on-

the-water repairs to steel-hulled ships are nothing new, working with aluminum presents far greater challenges. While dry docking these ships would address these welding challenges, it is not always feasible. With global reach, U.S. Navy ships can be nearly anywhere on earth, and dry docks rarely are nearby.

In addition, the dry docking process wreaks havoc on the Navys intricate de-ployment scheduling. As a war-fighting machine, the Navy and its ships must be at the ready and in position to move at all times. The cost of dry docking is much higher than keeping the ship in the water when performing mainte-nance and repair.

The Navy has been searching for new weld-repair methods for its aluminum-hulled ships beyond dry docking, which currently is the only option. It may have found one with a promising new tech-nique: underwater aluminum gas metal arc welding (GMAW) in a hyperbaric chamber.

Phoenix Intl., Largo, Md., an under-water services company that has held the Navys Diving Services contract for the past 15 years, is performing tests at Bay-ou Vista, La., with a third-party auditor validating the results.

Underwater Aluminum Welding: A Tough PropositionAluminum is generally considered much more difficult to weld than steel. For example, aluminums high thermal

conductivity and low melting point can easily lead to burn-through and warp-age problems if proper procedures are not followed. Aluminums high thermal conductivity means the material tends to act as a heat sink, making fusion and penetration more difficult.

In terms of chemical composition, aluminum has a high maximum solu-bility for hydrogen atoms in the liquid form and a low solubility at the solidi-fication point. This means that even a small amount of hydrogen dissolved in the liquid weld metal will tend to escape as the aluminum solidifies, and porosity is likely to occura great cause of con-cern during the welding process.

All-aluminum U.S. Navy littoral combat ships (LCS-2s) began enter-ing service in 2009, creating an urgent

Case Study

Ditching the dry docks in favor of the chamber Underwater aluminum GMAW in a hyperbaric chamber helps keep aluminum-hulled ships afloat



need to develop a dependable, certified underwater aluminum welding process.

Stick welding, or shielded metal arc welding, does not work well on alumi-num, so we had to develop a GMAW procedure for performing underwater dry-chamber aluminum welding re-pairs, explained Justin Pollack, under-water ship husbandry/underwater weld-ing program manager for the Naval Sea Systems Command and supervisor of salvage and diving for the U.S. Navy.

Phoenix has been developing the new process for more than two years. Ultimately, the companys procedures must pass three hyperbaric aluminum weld tests: 5083 alloy welded to itself; 5083 alloy welded to a 6000-series al-loy; and a 6000-series alloy welded to another 6000 series.

While welding aluminum on dry land poses a number of challenges, welding in an undersea environment vastly complicates the process. Early on in development of the new proce-dure, aluminum welds performed on the surface passed X-ray tests, but when the same process was performed in the water, the welds experienced significant porosity, Pollack said.

We realized that we have to control the environment. The welders are work-ing around water, so humidity is an is-sue, and because they are working at depth, pressure is increased.

Ken Elliott, welding manager for Phoenix Intl., echoed the concerns about pressure.

Underwater, a dry environment such as a hyperbaric chamber has an elevated

pressure, and elevated pressure will find any route back to ambient pressure, he said. The habitat environment is trying to escape. Even through the small space between the wire conduit and the wire itself, pressure tries to escape to the sur-face, taking contaminants with it.

Given the pressure variation, impuri-ties in the habitat atmosphere, including moisture, can work their way into the weld, contaminating the weld bead and leading to porosity, which significantly weakens the welding joint. Beyond that, underwater welding in a hyperbaric chamber presents its own set of challenges.

The hyperbaric chamber, also known as a habitat, measures about 6 feet tall by 4 feet wide and 5 feet deep, explained Nathan Martin, welder/diver for Phoenix Intl.

Ditching the dry docks in favor of the chamber Underwater aluminum GMAW in a hyperbaric chamber helps keep aluminum-hulled ships afloat

The Navy has been searching for new weld-repair methods for its aluminum-hulled ships beyond dry docking. A promising new techniqueunderwater aluminum gas metal arc welding (GMAW) in a hyperbaric chamberhas the potential to allow welders to make necessary repairs on-site.



We are welding in 23 ft. of water with everything around us that a nor-mal welder would have. In the chamber, we have a greater sense of how clean to keep the work area. We are covered in hoses and leads and have to make sure that we can make the necessary body movements to weld comfortably, so we practice those before we actually weld.

Commercial welder/diver Whitney Ehrgott, Martins colleague at Phoenix Intl., agreed, and also has learned to rely on senses beyond sight to create proper welds.

Our visibility diminishes when weld-ing underwater, so we have to feel and hear the process, and these heightened senses help us to create better welds.

The Right Process, Procedures, and Equipment Make All the DifferencePhoenix Intl. used a Power Wave S350 welding machine, a Power Feed 25M wire feeder, and a SuperGlaze 5556

364-in.-diameter wire from Lincoln Elec-tric, Cleveland. The power source and wire feeder are located above the sur-face of the water on land, connected to a push/pull welding gun with a 50-ft. gun cable located 24 ft. underwater in a hyperbaric chamber. The process and procedures have been carefully selected for easy repeatability anywhere in the world. Accordingly, the team selected procedures that used 100 percent argon as the inert shielding gas.

One project goal was to develop a way to repair an aluminum ship in any theater throughout the world. So we wanted a welding process that would work without using helium in the gas mix. If we cant find the right gas mix, we cant repair the ship, Elliott explained.

The standard Power Mode advanced process on the power source lends itself to using 100 percent argon inert gas very easily, according to Elliott, while pro-viding consistent weld penetration with reduced voltage input. The process uses

high-speed regulation of output power to deliver fast response to changes in the arc. The result is improved GMAW performance, including low spatter, uni-form and consistent bead-wetting, and controlled penetration.

Getting power and wire to the weld-ing gun, with a feeding distance in this application of 50 ft. from the wire feed-er, is another challenge.

Lincoln has provided true 100-ft. separation between the power source and wire feeder, and by using a 50-ft. push/pull gun on top of that, we can get huge separation from where we need to plug in and get power to the actual arc, Elliott said.

Also, we have not experienced wire failure in terms of pushing or pulling it through a 50-ft. gun cable. A 50-ft. gun cable is essential in repairing the ships in the water, and 50 ft. is the extreme distance at which you can push/pull any soft material like aluminum, Elliott continued.

While welding aluminum on dry land can be tricky, welding in an undersea environment vastly complicates the process. Early on in development of the new procedure, aluminum welds performed on the surface passed X-ray tests, but those made in water had significant porosity.



By Dirk Herzog

W hen band saw cutting I-beam, square, and round tubing, straight cuts are crucial to preparing the part properly for welding. Parts with crooked cuts make weld-ing diffi cult, to say the least, and as a result, welders often must use a fi ller or additional welding wire to fi ll the gap left by the uneven edge. In more severe cases, the parts with uneven cuts may have to be recut or scrapped altogether, which is both costly and time-consuming.

If you are performing structural cuts with a band saw, consider these tips to help ensure that edges are straight and that welders can join parts easily and effi ciently. Keep in mind the importance of rou-tine maintenance on the band saw machine. If a machine has problems with its feed system or its variable-speed system, it will negatively affect the life of the band saw blade.

Know the Sawing Parameters The best way to ensure the cuts you make will be straight is to set your saw-ing parameters correctly. Set the ma-chine to the correct blade speed and cut rate for the material being cut. As a rule, slow the blade for tough material and increase speed for softer material.

Also, check to make sure the con-veyor rollers that hold the material are aligned properly. Rollers that are out of alignment can lead to crooked cuts.

Set the Tension ProperlyUse a gauge to measure and set the ten-sion on the blade in the band saw ma-chine. Most band saws work best with the blade tension set to a minimum of 25,000 PSI or a maximum of 32,000 PSI. Anything less than 25,000 PSI leads to poor beam strength, band fatigue, or

crooked cuts. Tensions set to 32,000 PSI or more can break the band, crack the gullets, or wear out the machine bearings.

Cut From the Back of the Weld SeamFor applications that involve cutting through a weld seam on tubing, it is easier and more effi cient for the band saw blade to enter the ma-terial from the back of the weld seam. Cutting directly into the weld seam serves as a shock point to the blade teeth and often results in shorter blade life or teeth strippage.

Secure the BundlesWhen band sawing bundles of material, it is best to strap down the entire bundle or tack weld the ends of the bun-dle to prevent any pieces from moving. If the individual pieces vibrate or move during

the cutting process, there is a possibility that the teeth will strip.

Use Proper LubricationThe proper amount of cutting lubri-cant, also known as coolant, will help extend blade life. Band saws use a fl ood-coolant or a mist system to lubricate the blade. Not only does lubrication help maximize blade life, it also helps mini-mize the buildup of metal chips that result when the material is cut. Coolant should wash over the blade as it enters

Technology Overview

Band sawing structurals

Cutting tips that lead to better welds

Photos courtesy of Simonds Intl., Fitchburg, Mass.

MayJune13PWT_B.indd 30 4/30/13 4:14 PM


and exits the cut. Although the coolant is recirculated and used continuously throughout the cutting process, be sure to replace water that evaporates from the mixed solution.

Breakin New Blades Be sure to break in new band saw blades before you ramp them up to full-speed cutting. This practice will hone the teeth and extend blade life. The best way to break in new bimetal blades is by reduc-ing the normal feed rate by half during this initial period. The band speed isnt what breaks teeth during blade break-in; its the pressure an excessive feed rate produces that is most damaging.

To break in your bimetal saw blade, multiply the recommended blade speed by 25 percent, and cut that number of square inches. Be sure to run the blade

at 50 percent of the recommended blade feed rate. Once you approach the end of the break-in period, gradually bring your band saw feed rate up to normal.

Use the Right BladeThe right band saw blade makes all the difference when cutting structurals, where the desired outcome is a clean, straight cut that simplifies weld prep applications. Be sure to choose a blade that can withstand the stresses of struc-tural cutting, produce a smooth finish, and ensure maximum blade life. Also, optimal tooth geometry is key to creat-ing faster cutting rates, which increase productivity. n

Dirk Herzog is West Coast regional sales manager at Simonds Intl., 135 Intervale Road, P.O. Box 500, Fitchburg, MA 01420, 978-424-0100, www.simondsinternational.com.

When sawing material bundles, tack weld the ends or strap down the entire bundle to help keep the pieces in place.

MayJune13PWT_B.indd 31 4/30/13 4:15 PM


Consumables Corner | Nino Mascalco

Do you have a consumablesquestion for Nino?

Send comments and technical questions in writing to:

Amanda Carlson, Associate EditorPractical Welding Today833 Feather stone RoadRockford, IL 61107-6302

Fax: 815-484-7788E-mail: [email protected]

Our company is using 0.045-in.-dia. mild steel solid wire for GMAW with 90 percent argon/10 percent CO2 shielding gas. A majority of our base metal is to 1 in. thick welded out of position about 30 percent of the time. We are considering a change in our welding process to reduce lead-times. Can you offer some in-sight to help us choose the best process?

There are numerous variables to consid-er, which would take an in-depth study to determine the best process based on your production, both currently and in the future. However, here are some questions to ask when selecting a differ-ent welding process or wire.

How much extra capacity do I require or anticipate requiring? How much can I handle without creating material-fl ow bottlenecks?

What are my budgetary limits for new machine purchases, training, and welding qualifi cations?

What equipment do I have cur-rently? Is it multiprocess equipment? What are the maximum operating con-ditionsduty cycle, wire diameter, peak power output, and process control?

What is the skill level of our work-force?

Are there any environmental work condition limitations?

What is the surface condition of the steel before its welded?

If you dont foresee any of these fac-tors being a major hindrance in chang-ing your welding process, then youve got several possible solutions to consider.

A larger-diameter solid wire, such as 0.052 in. or 116 in., will provide higher deposition rates without incurring much

additional cost. As long as your equip-ment has the capability to run at higher welding currents and duty cycles, this would be a relatively simple change. Keep in mind the weld joints need to be relatively free of contaminants, espe-cially mill scale. With the shielding gas you are using, welding in spray-transfer mode will produce a good-quality weld with high deposition effi ciency and low fume generation.

If your machines have the ability to run in pulse-welding mode, then you can weld lightweight material with the larger-diameter wire too, which helps reduce wire changeover time. In pulse mode, the ability to weld with lower voltages and currents still produce a high-quality weld with minimal spat-ter and distortion. Pulse mode also im-proves out-of-position welding speeds.

If speed is an important factor, you might want to think about changing to a metal-cored wire. Metal-cored arc welding (MCAW) can produce higher deposition rates at similar arc currents compared to solid wire. This reduces the overall heat input because youre able to achieve faster travel speeds, which can also minimize distortion.

Metal-cored wires are not designed to weld out of position unless you have pulsing capabilities. And just like with solid wire, the weld joints need to be relatively clean and free of mill scale.

The fi nal manual welding process to consider is ux-cored arc welding (FCAW), which can produce quality welds with good deposition rates. How-ever, because it is necessary to remove slag, the deposition effi ciency is about 12 to 15 percent lower than GMAW or MCAW. Additionally, the fume gener-ated and weld cleanup time are signifi -cantly higher.

With that said, FCAW ller metals are designed to handle moderately heavy rust and mill scale without affecting weld quality. If you currently dont have the ability or time to shot-/sandblast or grind weld joints before you weld, this would be a better alternative. FCAW wires also are available in two different typesall-position and fl at/horizon-tal positionneither of which require pulse-welding capabilities.

Finally, depending on your produc-tion quantity, you could also look into robotic welding or automated sub-merged arc welding (SAW). These proc-esses may require some raw material design changes for xturing and posi-tioning, which can be rather costly.

Nino Mascalco is application engineering man-ager at ESAB Welding & Cutting Products, 411 S. Ebenezer Road, Florence, SC 29501, 636-485-2253, www.esabna.com.

The thought process behind changing a weld process

A larger-diameter

solid wire will provide

higher deposition rates

without incurring much

additional cost.



Arc Welding 101 | Paul Cameron

I am looking for some insight on the best approach, best practices, and industry standards for quoting weldments. There seems to be a great deal of information out there about deposition rates and travel speeds, but not a lot about the ad-ditional variables like clamping, part handling, cleaning, grinding, and packaging. Any insight you can pro-vide is greatly appreciated.

Matt W.South Bend, Ind.

Before quoting any job, you need to de-

termine a couple of things, mainly your arc-on time and cycle time. Following are arc-on time guidelines I have devel-oped for quoting purposes:

20 percent arc-on timeOccurs in a typical manual workcell that as-sembles, tacks, and welds parts.

40 percent arc-on timeOccurs in a typical manual workcell that receives a tacked assembly and fi nish-welds it.

60 percent arc-on timeOccurs in a manual workcell where the welder rarely moves, doesnt add parts, and is continuously welding. Also may occur in a robotic workcell that welds many

short (less than 4 in.) welds with lots of arm movement and touch sensing.

80 percent arc-on timeOccurs in a robotic or automated workcell that completes continuous or multipass welds and does little touch sensing.

When estimating inches of weld to be laid, fi gure fi llet welds 14 in. and shorter will be single-pass welds. Welds bigger than that should be calculated as three-pass welds, or weld length multi-plied by 3.

These guidelines you establish for yourself are important. Get them wrong and youll never make money, and thats why were hereto make money and keep folks employed.

I once had an employer that calcu-lated weld cost simply by knowing how many inches of welds the weldment would require. The estimates were very accurate, but a system like that would take years to develop and theirs did.

My advice is to apply these rules of thumb and fi nd yourself a good weld calculator program that you are com-fortable with. Im not big on reinventing the wheel.

Paul W. Cameron, CWI, is quality control manager for Thomas & Betts, Hager City, Wis., 507-269-7142 or [email protected]. He also is a member of Practical Welding Todays Editorial Review Committee.

Do you have a weldingquestion for Paul?

Send comments and technical questions in writing to:

Amanda Carlson, Associate EditorPractical Welding Today833 Feather stone RoadRockford, IL 61107-6302

Fax: 815-484-7788E-mail: [email protected]

Advice for quoting weldments

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Testing Composites for Auto Applications

Voids in Electronic Parts Yield to Ultrasound

Developing a Microscale Fatigue Testing Technique

Composites Testing/Characterization

AN ASM INTERNATIONAL PUBLICATION

JUNE 2013 VOL 171, NO 6

www.asminternational.org

Russ Kappius, a mountain-bike enthusiast and research geo-physicist/software developer, wanted a bicycle hub with morespeed and responsiveness. After working out a design for a novel,oversized hub and high-performance drive assembly that wouldtransfer more power from pedal to chain to wheel, Kappiuspatented the concept. In late 2011, Kappius discovered directmetal laser sintering (DMLS), an industrial additive manufactur-ing technology from EOS GmbH that met his companys rapidturnaround needs and enabled it to produce parts to exactingspecifications and with additional design complexity.

The beauty of the lightweight-yet-durable hub comes from thesleek carbon-fiber shell (handmade by his son), as well as the driveassembly housed insideincluding a drive ring, toothed innerring, and pawls (or flippers), all made using DMLS. The techno-logical advance in the system comes from two developments: theoversized designits about twice the current standard diame-terand many more points of engagement than standard designs.These two features constitute the heart of the hubs intellectual property and allow a cyclist to translate the act of ped-aling into increased drive force. www.eos.info/en.

Sprayable foam stops bleeding Remedium Technologies Inc., College Park, Md., received a $500,000 Small Business Innovation Research grant

from the National Science Foundation to test sprayable foam for rapidly halting traumatic bleeding. In collaborationwith Massachusetts General Hospital and the University of Maryland, Remedium will complete preclinical trials toevaluate the safety and efficacy of Hemogrip Foam in controlling noncompressible hemorrhaging, i.e., bleeding not ac-cessible to direct pressure.

The technology is based on chitosana natural biopolymer found in the exoskeleton of shrimp, crabs, and othercrustaceans. Chitosan is unique as a natural material because it is biocompatible, antimicrobial, and highly durableunder a wide range of environmental conditions. When applied to wounds, Hemogrip creates a nanoscale 3-D mesh,rapidly coagulating blood and staunching blood loss. It is dispensed from a handheld, lightweight canister that is easyto use by surgeons, soldiers, and others. It can be removed quickly and easily without damaging tissue, and because it

is based on chitosanthe second most abundant biopolymer on earthit isalso inexpensive. http://remediumtechnologies.com.

Seahorse armor inspires robotics Seahorse tails are exceptionally flexible due to their structure, made up of

bony, armored plates, which slide past each other. Researchers at the Universityof San Diego are hoping to use a similar structure to create a flexible roboticarm equipped with muscles made out of polymer, which could be used in med-ical devices, underwater exploration, and unmanned bomb detection and det-onation.

Researchers wanted to see if the plates in the seahorses tail act as an armor,so they took segments and compressed them from different angles. They foundthat the tail could be compressed by nearly 50% of its original width before per-manent damage occurred because the connective tissue between the tails bonyplates and muscles bore most of the load from the displacement. Even when thetail was compressed by as much as 60%, the spinal column was protected frompermanent damage. The next step is to use 3-D printing to create artificial bonyplates, which would be equipped with polymers that would act as muscles. Theprotected, flexible arm would be able to grasp a variety of objects of differentshapes and sizes. www.ucsd.edu.

Taking 3-D printing for a spin

ADVANCED MATERIALS & PROCESSES JUNE 20134

interestof material

Russ Kappius, developer of the Kappius hub, and hisson, Brady, professional mountain-bike racer, outsidetheir garage shop. Courtesy of Kappius Components.

A seahorse skeleton and its bony plates are shownthrough a micro CT scan. Courtesy of McKittrick Research Group/Jacobs School of Engineering, UC San Diego.

Synthesized niobium oxide suits high-performance supercapacitorsResearchers at UCLA

synthesized a materialthat shows high capabilityfor both the rapid storageand release of energy. Theteam defines the charac-teristics of a synthesizedform of niobium oxidewith a great facility forstoring energy. The mate-rial would be used in a su-percapacitor, which combines the high storage capacity of lithium ion batteries with therapid energy-delivery ability of common capacitors. The team said the development couldlead to extremely rapid device charging, in applications from mobile electronics to indus-trial equipment. For example, supercapacitors are now used in energy-capture systems thathelp power loading cranes at ports, reducing the use of diesel fuels.

Researchers synthesized a type of niobium oxide that demonstrates substantial storagecapacity through intercalation pseudocapacitance, in which ions are deposited into thebulk of the niobium oxide in the same way grains of sand are deposited between pebbles.As a result, electrodes as thick as 40 can quickly store and deliver energy as fast as elec-trodes more than 100 times thinner. For more information: Prof. Bruce Dunn, 310/825-1519, [email protected], www.ucla.edu.

Steel eliminates weight gap with aluminum car bodiesThe latest research study by WorldAutoSteel, Detroit, suggests that in the near future,

steel auto body structures can be as lightweight as todays aluminum bodies, while meet-ing all crash performance standards and at cost comparable to todays steel structures. Thestudies also show how car makers can form and fabricate sophisticated steel designs and ac-celerate their implementation in production vehicles.

Building on a weight reduction of 35% announced in 2011 in its initial FutureSteelVehi-cle (FSV) design, the most recent studies boost lightweighting to 39%, compared to a base-line vehicle using an internal combustion engine. The optimized FSV body weighs 176.8 kg,putting steel on par with todays aluminum-intensive production designs. These lightweight,advanced high-strength steel (AHSS) body structures, designed to carry heavier electrifiedpowertrains, fall in line with the lightest internal combustion engine aluminum vehicles, andare on par with other concepts featuring alternative materials. www.worldautosteel.org.

Solar-powered airplane flies day and nightThe sun-powered Solar Impulse aircraft will fly with more than 6000 parts made from 11

different products from Solvay, Brussels, Belgium, including high-strength, lightweight plas-tics, battery components, lubricants, insulation, and solar panel film coatings. Solar Impulse

is the worlds first solar-powered airplane capa-ble of flying day and night without fossil fuel.

The plane has a wingspan that accommo-dates more than 10,000 solar panels coveringthe wings surface. These cells capture the solarenergy that turns its propellers, allowing theaircraft to fly. Solvays PVDF (Solef ) andECTFE (Halar) polymers are used for ultra-thinsingle layer films, laminated films, and adhe-sives that encapsulate the cells to reduce theimpact of stressors, deformations, temperaturevariations, and solar radiation that occur when

newsindustry

briefs

The Steel Market DevelopmentInstitute, a business unit of theAmerican Iron and SteelInstitute, Washington, D.C., hostedthe 12th annual Great Designs inSteel Seminar in May in Livonia,Mich. It brought togetherautomotive and steel industryleaders to discuss the latestautomotive steel usage trends. Thetechnical program featured morethan 35 presentations highlightingsteels role in the automotiveindustry, including advanced high-strength steel (AHSS) technologiesin new vehicle platforms,advancements in the developmentof third-generation AHSS, steeldesigns to meet upcoming fuel andemissions requirements, andsteels unique advantages as anautomotive material.www.autosteel.org.

A study conducted by EDAGGroup, Germany, andcommissioned by the Aluminum inTransportation Group of the U.S.Aluminum Association, Arlington,Va., shows that all-aluminumvehicles can shed more than 40%body mass, boosting fuel economyby 18% when combined withsecondary mass savings and otherdesign changes. The study waspresented at the Society ofAutomotive Engineers (SAE)World Congress during a paneldiscussion on advances in lowerweight materials. The researchused a full aluminum body andclosures to achieve almost 3 thebody mass reduction over theEnvironmental Protection Agencystudys high strength steel vehicle,while maintaining safety andperformance standards.www.drivealuminum.org.

METALS POLYMERS CERAMICS


Illustration of niobium oxide synthesized by UCLA researchers.Courtesy of UCLA/Nature Materials.

ADVANCED MATERIALS & PROCESSES JUNE 2013 7

flying. Solvay materials also reduce overall aircraft weight.www.solvay.com.

High impact polymer strengthens sky and sea applications

U.S. Naval Research Laboratory Chemistry Division (Wash-ington, D.C.) scientists developed a second generation, cost-ef-fective polyetheretherketone (PEEK)-like phthalonitrile resinthat demonstrates superior high temperature and flammabilityproperties for use in numerous marine, aerospace, and domes-tic applications. The resin can be used to make composite com-ponents by established industrial methods such as resin transfermolding (RTM), resin infusion molding (RIM), filament wind-ing, prepreg consolidation, and potentially by automated com-posite manufacturing techniques such as automated tape layingand fiber placement.

Phthalonitrile-based polymers are a class of high tempera-ture thermosets that remain strong at temperatures to 500C,are nearly fireproof, and are easily processed into shaped fiberreinforced composite components by low cost, nonautoclavetechniques. For more information: Daniel Parry, 202/767-2541,[email protected], www.nrl.navy.mil/chemistry.

Titan Spine, Mequon Wis., has clinical data that supports the use of itsEndoskeleton titanium interbody cage for achieving rapid lumbar fusionand improved patient outcomes. The study looked at 77 patients with amean age of 46 years who underwent an anterior lumbar interbodyfusion procedure using the Endoskeleton interbody device. A total of138 spinal segment levels were treated. Radiographic analysis revealeda 100% fusion rate between 6-12 months, with no appreciablesubsidence and an interobserver reliability rate of 95%.www.titanspine.com.

Harper International, Buffalo, N.Y., is hosting the Carbon Fiber R&DWorkshop event July 2526. The goal is to connect peers in the carbonfiber research space with an opportunity to network and share insightson material and process technology innovations. Harpers Carbon FiberMicroline research system will be on display, a flexible toolkit designedto support research and development efforts, along with an advancedUHT (ultrahigh temperature) furnace for carbon fiber production.www.carbonfiberworkshop.com.

Yanfeng USA Automotive Trim Systems, Riverside, Mo.,will construct a 258,000-sq-ft manufacturing plant in theKansas City area. The Michigan-based subsidiary of YanfengVisteon of China, a General Motors supplier, plans to buildthe $45 million manufacturing and sequencing facility andexpects to create 263 new jobs. The Riverside plant willmanufacture interior trim components, including doorpanels, floor consoles, and instrument panels for GeneralMotors assembly plants in Kansas City, Kan., andWentzville, Mo. Construction is expected to begin in the nextmonth and the plant will be operational in early 2014.www.yf-usa.com, www.thinkkc.com.

newsindustry

briefs

Staples Inc., Framingham, Mass.,is the first major U.S. retailer tosell 3-D printers. The Cube from3D Systems Inc., Rock Hill, S.C.,is available on Staples.com for$1299.99 and will be sold in a fewstores by late June. It includes Wi-Fi, Mac or Windows compatibility,and 25 3-D templates. It can printitems up to 5.5 5.5 5.5 in.using material cartridges in 16different colors. Users can printfrom a template or create a designusing Cubify Invent software, soldseparately. www.staples.com,www.3DSystems.com.

Graphene Technologies, Novato,Calif., was issued U.S. PatentNumber 8,420,042 for a processfor atom-by-atom synthesis ofgraphene by the exothermicchemical reduction of CO2.According to company sources, theprocess represents a dramaticdeparture from current methods ofproducing graphene, such aschemical vapor deposition. Bycombusting magnesium in thepresence of CO2, bulk volumes ofpristine, few-layer grapheneplatelets are produced fromcommonly available feedstock.CO2 is used to oxidize magnesiumat temperatures up to 7000F,forming nanoscale magnesiumoxide and carbon.www.graphenetechnologies.com.

New metamaterial boosts invisibilityEngineers at Stanford University, Calif., took another step toward designing a meta-

material that works across the entire visible spectrum. The new material exhibits a refrac-tive index well below anything found in nature, such as air, whose refractive index hoversjust above 1. Interesting physical phenomena can occur if this index is near-zero or nega-tive. Researchers designed a single metamaterial atom with characteristics that would allowit to efficiently interact with both the electric and magnetic components of light. The teambegan with a 2-D planar structure then folded it into a 3-D nanoscale object, preserving theoriginal properties. The metamaterial consists of nanocrescent-shaped atoms arranged ina periodic array and it exhibits a negative refractive index over a wavelength range ofroughly 250 nm in multiple regions of the visible and near-infrared spectrum. A few tweakscould make it useful across the entire visible spectrum. For more information: Ashwin Atre,[email protected], www.stanford.edu.

Stainless steel fuel cell charges phonesPoint Source Power Inc., Alameda, Calif.,

used technology developed at LawrenceBerkeley National Laboratory (Calif.) to createan inexpensive way to recharge cell phones inthe developing world. The new device is basedon a solid oxide fuel cell powered by burningcharcoal, wood, or cow dung. The fuel cell sitsin the fire and is attached to circuitry in a han-dle that is charged as the cell heats to 800C.The handle contains an LED bulb, which canbe detached and used for lighting or to chargea phone. The fuel cell tolerates contaminantslike sulfur and carbon, which would kill simi-lar devices, says CEO Craig Jacobson, who co-invented the device called VOTO whileworking as a materials scientist at BerkeleyLab. Replacing most of the ceramics in the fuel cell with stainless steel allows it to withstandwelding and thermal shock and is less expensive to manufacture. VOTO will debut in Kenyalater this year. www.lbl.gov, www.pointsourcepower.com.

Nanowires grown on graphene have surprising structureWhen engineers at University of Illinois, Urbana-Champaign, set out to grow compound

semiconductor nanowires on top of a sheet of graphene, they did not expect to discover a newparadigm of epitaxy. The self-assembled wires have a core of one composition and an outerlayer of another, highly desirable for advanced electronics applications. Led by professor Xi-

uling Li, the research team used a method called van der Waals epitaxy to first grownanowires on a flat substrate of semiconductor materials, such as silicon.

The group has since grown nanowires made of indium gallium arsenide (InGaAs)on a sheet of graphene, which is more flexible than silicon. It also conducts like ametal, allowing for direct electrical contact to the nanowire. Researchers pumpgases containing gallium, indium, and arsenic into a chamber with a graphene sheetand the nanowires self-assemble into a dense carpet. By using three elements, thegroup made a unique finding: The InGaAs wires grown on graphene spontaneouslysegregate into an indium arsenide (InAs) core with an InGaAs shell around the out-side. By tuning the ratio of gallium to indium in the semiconductor mix, researcherscan tune the wires optical and conductive properties. For more information: Xiuling Li, 217/265-6354, [email protected], www.illinois.edu.

A dense array of InGaAs nanowires grown on graphene. Courtesy of Parsian Mohseni.


EMERGING TECHNOLOGY

Craig Jacobson, in the test labs of PointSource Power. Courtesy of JulieChao/Berkeley Lab.


PROCESS TECHNOLOGYnewsindustry

briefs

Ikonics Corp., Duluth, Minn., isworking with Lockheed MartinCorp., Bethesda, Md., to develop anew method of machining ceramicmatrix composite (CMC) materialsusing particle beam technology.CMC is difficult to machinebecause of its hardness andnonuniformity. According tocompany officials, Ikonicstechnology eliminates edgedamage to the material caused byremelt with lasers or delaminationwith waterjet or mechanicalmachining methods.www.ikonics.com.

Materials science and engineeringprofessor Jiann-Yang Jim Hwangand 2012 Ph.D. graduate ZhiweiPeng will receive MichiganTechnological Universitys 2013Bhakta Rath Research Award forwork involving the use ofmicrowaves in steelmaking. Theaward is endowed by MichiganTech alumnus Bhakta Rath and hiswife, Shushama, and recognizes adoctoral student and facultyadvisor for exceptional research.The research entails theoreticaland experimental work on usingmicrowaves to heat materials,particularly magnetic substances,and also provides guidelines formaking large-scale microwavefurnaces for industrial use.www.mtu.edu.

Robotic paint-stripping system wins Edison AwardA robotic paint-stripping system being de-

veloped by Carnegie Mellon Universitys Na-tional Robotics Engineering Center (NREC),Pittsburgh, and Concurrent Technologies Corp.(CTC), Johnstown, Pa., was named a Gold win-ner in the materials science category of the 2013Edison Awards, announced April 25 in Chicago.The Advanced Robotic Laser Coating RemovalSystem uses lasers mounted on mobile roboticplatforms to remove paint and coatings fromfighter and cargo aircraft. NREC and CTC aredeveloping the system for the U.S. Air Force.

NREC is building six autonomous mobile robots, each equipped with a high-powerlaser coating remover developed by CTC. It uses a continuous wave laser to strip paint andother coatings from aircraft rather than traditional abrasives or paint removers. The lasercan selectively remove coatings while a HEPA system collects debris as it is removed fromthe aircraft. As part of a two-year project, the robots will be deployed in teams to removepaint and other coatings from aircraft at Hill Air Force Base in Utah. For more information:Byron Spice, 217/268-9068, [email protected], www.cmu.edu.

Gas nitriding strengthens mini medical devicesAn established automotive manufacturing technique holds promise for enhancing the

performance of micro and nanoscale medical devices. Masaru Rao, assistant professor atBourns College of Engineering, University of California, Riverside, received a $400,000award from the National Science Foundation to explore the potential to strengthen minia-turized titanium medical devices. Coating of machined parts to increase hardness is com-monplace at the macroscale, but is constrained at the micro and nanoscale by challengessuch as maintaining coating uniformity and quality over complex structures.

To address these limitations, Rao will use gas nitriding, a technique widely employedto increase the wear resistance of macroscale metal parts for automotive applications, suchas case-hardened engine camshafts. Machined part surfaces are strengthened by heatingin a nitrogen atmosphere, causing nitrogen to diffuse into the metal. Rao believes this tech-nique holds significant potential for tiny medical devices because gas nitriding can be ap-plied to devices after fabrication and also avoids limitations of coating-based processes.The diminutive dimensions will make it easy to diffuse nitrogen throughout the entirestructure to allow through-thickness strengthening, says Rao. For more information:Masaru Rao, 951/827-5870, [email protected], www.ucr.edu.

Resin transfer molding suits composite leaf springsBenteler-SGL of Austria and Henkel AG & Co., Dsseldorf, Germany, developed a

process for resin transfer molding (RTM) of glass-fiber-reinforced leaf springs, using apolyurethane matrix resin. Compared to conventional steel leaf springs, com-posite versions are up to 65% lighter.

Henkels Loctite MAX 2 is a polyurethane-based composite matrix resin thatcures significantly faster than epoxy products usually employed for the RTMprocess. Due to its low viscosity, the resin more easily penetrates and impreg-nates the fiber material, enabling very short injection times to be applied. Resininjection processes such as RTM are widely used to make automotive compos-ites because they make it possible to control the curing reaction more reliably,either by adjusting the temperature or adding an accelerator. For more infor-mation: Lisa Kretzberg, [email protected], www.henkel.com.

Working together, Henkel and Benteler-SGL are mass-producing lightweight, fiber-reinforced leaf springs based on polyurethane matrix resin.

This rendering shows how a team of robots might be deployed to strip paintfrom a C-130 cargo plane.


SURFACE ENGINEERINGnewsindustry

briefs

Researchers at McMasterUniversity opened theBiointerfaces Institute, Canadasfirst facility for developing uniquenew surfaces using high-speedrobots and other advancedtechnology. Millions ofcombinations of biological agentsand complex surfaces will betested in pursuit of rapid solutionsto stubborn health, safety, andother problems. The accumulatedresults will reside in a database toassist researchers from bothinside and outside the university.www.mcmaster.ca.

Fraunhofer Institute for ElectronBeam and Plasma TechnologyFEP, Germany, introduced thenewest developments in vacuumcoating technology at the recentinternational vacuum conferenceSVC TechCon 2013 held inProvidence, R.I. The new andhighly efficient processes forcoating large areas, such asarcPECVD (hollow cathode arcPECVD), plasma-activated high-rate evaporation using a dualcrucible, and the sputtering ofindium-free transparentconductive coatings werepresented. All three technologiesare ready for industrial use.www.fep.fraunhofer.de/en.

PPG Industries, Pittsburgh,opened its new automotive OEMcoatings development andapplication center in Tianjin, China.The facility is the first of its kindlocally and will focus ondeveloping automotive coatings inChina. It is PPGs largest coatingsmanufacturing facility and theexpansion significantly increasesthe plants production capacity forwaterborne coatings. The center isalso equipped with advancedmachinery to simulate automaticcar painting processes.www.ppg.com.

Pretreatment process boosts automotive aluminum use Henkel Corp., Detroit, began using the Bonderite Flex Process on 2013 Ford F-150

trucks made in North America. The process enables a significant increase in aluminumuse by replacing traditional zinc phosphating with a zirconium oxide pretreatment. The2013 F-150 features an all-aluminum hood. Once aluminum content on vehicles reachesapproximately 30%, the use of zinc phosphate becomes more difficult to control and leadsto an increase in sludge generation. In addition to enabling more aluminum use, zirconiumoxide provides better corrosion protection and reduces sludge waste by two-thirds.www.henkel.com/automotive.

Cold spray coatings technology programA cold spray coating technology program established at the University of Wisconsin,

Madison, is aimed at fundamental materials science research and industrial applications.The program includes a commercial scale, high pressure CGT 4000-34 Kinetik system. Inthe cold spray process, powder particles of the coating material are propelled at supersonicvelocities onto the surface of a part or substrate to form a dense coating. The particle tem-perature is low and deposition occurs in solid state. The low temperature minimizes oxi-dation, thermal decomposition, and other phase changes in the powder material duringdeposition. Coatings can be synthesized with novel micro and nanostructures with en-hanced properties. High deposition rates in the cold spray process make it attractive for ad-ditive and near-net-shape manufacturing, as well as for low temperature dimensionalrestoration and repair. Research and development activities include aluminum-alloy coat-ings to address corrosion issues in Navy ships under an Office of Naval Research program,energy and electronics sector applications, and hybrid coatings. For more information:Kumar Sridharan, [email protected], www.wisc.edu.

Clad pipe manufacturing facility opens in OhioAbakan Inc., Miami, performed a test run on its CermaClad high-intensity arc lamp

prior to the April opening of its first clad pipe manufacturing plant in Euclid, Ohio. Theplant is a 1-line CermaClad corrosion-resistant clad pipe manufacturing facility withthe capacity to produce up to $60 million of clad pipe for use in upstream oil and gasproduction. The plant is the first production facility to use MesoCoats CermaClad high-speed large-area fusion cladding technology to produce a high quality product 40 timesfaster than weld overlay processes, and at significantly lower costs compared to otheralternatives.

MesoCoat Inc.s CEO, Andrew Sherman stated, Our new facility enables us to demon-strate continuous, automated production of 12-meter pipe segments, and is a major mile-stone towards offering cost effective asset protection in an effort to reduce the estimated$2.2 trillion wasted worldwide as a result of preventable corrosion and wear. www.abakaninc.com, http://mesocoat.com.

The clad pipe manufacturing

facility uses MesoCoats CermaClad high-speed

large-area fusioncladding

technology.

The U.S. Air Force operates and maintainsapproximately 24,000 turbine engines,and many components in these engines

are limited by fatigue life. Current strategies forestimating engine component lifetimes gener-ally rely on extrapolating mean fatigue lifetimebehavior from extensive experimental data-bases. Although these extrapolations may yield

overly conservative predictions[1-3], such strate-gies are critical for developing preventive main-tenance schedules that ensure safety at anaffordable cost. Significant savings may be real-ized by further developing and implementingmicrostructurally based mechanistic models of

fatigue behavior[2-4].

Fatigue behavior is weak link

Fatigue behavior is known to be a weak-linkprocess significantly influenced by local mi-

crostructural configurations[5,6]. Typically, lab-oratory scale tests are used to determine amaterials fatigue capability because these testsare relatively inexpensive and easily run to fail-ure. Fractography is often performed afterspecimen failure to determine which mi-crostructural features are associated with fa-tigue crack initiation and growth. These testsprovide lifetime-to-fatigue failure data underspecific loading conditions and microstructuralconfigurations.

Often, it is impossible to unambiguouslyidentify the mechanism of fatigue crack initia-tion and cyclic damage accumulation throughpost-mortem investigations, as many differentmicrostructural configurations can lead todamage accumulation and subsequent crack

initiation[6]. Fatigue properties of titanium alloymicrostructures are of particular interest be-cause of their use in critical aircraft and engineaerospace components.

Aerospace titanium alloys usually consist oftwo phases at service temperatures. The firstphase (beta) has a bcc structure and is moreductile, with lower strength, than the secondphase (alpha). The alpha phase is an hcp struc-ture with either lath-like or equiaxed grains, de-pending on the thermomechanical processingof the material. In laboratory scale fatigue testsof alpha + beta titanium alloys, fatigue crackstypically initiate via a facet formation on the

basal plane of primary alpha (p) grains[6-10].

The microstructural neighborhood surround-ing these grains also plays an important role inthe crack initiation process, and specific attrib-utes of these neighborhoods were identified.However, there are numerous paths for cyclicstrain to accumulate and various types of mi-crostructural neighborhoods may lead to simi-

lar fatigue lifetimes[6].Traditionally, researchers use in situ testing

methods to characterize mechanisms of damageaccumulation due to cyclic loading, and thesestudies have historically been limited to contin-uum length scales. Advances in micromachining

and small-scale testing capabilities[11,12] enable in-situ mechanical testing at the microstructural

scale[13-16]. Other advances facilitated quantitative3D analysis of microstructures, including high-fidelity crystallographic scale and orientation

information[17-19]. The current work describesmodifications of an in-situ monotonic mechani-

cal testing device[20,21] to enable in situ microscale

fatigue testing[22], coupled with subsequent serialsectioning methods to interrogate tested sam-ples. The long term goal of this work is to developa fatigue damage metric capable of representingand predicting fatigue damage accumulationwithin specific microstructural neighborhoodsusing a crystal plasticity finite element modeling(CPFEM) approach.

Development of a Microscale Fatigue Testing Technique

C.J. Szczepanski

P.A. Shade

M.A. Groeber

J.M. Larsen,

FASM*U.S. Air Force

Research Laboratory,

AFRL/RX

Wright-Patterson

Air Force Base, Ohio

S.K. JhaUniversal Technology

Corp.

Dayton, Ohio

R. WheelerUES Inc.

Dayton, Ohio

A microscale

fatigue testing

technique for

characterizing

mechanical

response

and relating

this response to

microstructural

features

contained

within the

tested

volume

enables more

accurate

approaches to

predicting

mechanical

behavior in

larger fatigue

volumes.


*Member of ASM

International

Fig. 1 A schematic ofthe microtesting rigused for in-situ testing.Adapted from [20].

Piezoelectric actuator

Alignment flexor Attocube x/y/z

50 mm piezoelectric Sample positioning

stage

50 mm

Load cell

Silicon grip

150 mm


Machining and testing

Microspecimens machined in targeted microstruc-tural regions isolate specific types of microstructuralconfigurations within a specimen. Micro-electro dis-charge machining (Micro-EDM) was used for coarsemachining of oversized specimen posts, and a focusedion beam (FIB) microscope was used for the final ma-chining of tensile specimen profiles. The gage sectionsof these microspecimens were typically 20 m diame-ter 50 m long, depending on the specific mi-crostructure being tested.

The testing platform used in this investigation wasdeveloped to accomplish monotonic loading in both

tension and compression[20,21]. The device, shown inFig. 1, uses a three-axis piezoelectric actuator to posi-tion the grip over the sample head. Once the specimenis seated within the grip, another piezoelectric trans-ducer is activated to apply a displacement, which in-duces a load in the specimen. Fatigue loadingexperiments are conducted under pseudo-load control,where a load cell is used to calibrate the applied piezo-electric actuator voltage necessary to achieve a desiredload level. Blocks of 500 to 1000 fatigue cycles are ap-plied by sinusoidally cycling the applied piezoelectricactuator voltage. Following each block, the appliedvoltage range is recalibrated for current load levels andan image is acquired to document any accumulateddisplacement within the specimen gage.

Ti-6Al-2Sn-4Zr-6Mo samples with a duplex mi-crostructure were tested in situ using this microscale

fatigue testing technique[22]. Experiments were com-pleted to identify the mechanisms of fatigue damageaccumulation, thereby linking specific microstructuralfeatures to mechanical behavior. For this work, a spec-imen was subjected to microscale fatigue testing atstresses (max) ranging from 860 to 980 MPa. The spec-imen was imaged at 20 kV using a backscattered elec-tron (BSE) detector.

Test results

Tested specimens are shown in Fig. 2, with the re-sulting mechanical response shown in Fig. 3. From Fig.2(a), it is clear that individual p grains are accumulat-ing localized fatigue damage in the form of slip bands,highlighted by the yellow arrows in Fig. 2(c). As fatiguecycling continues, slip lines continue to intensify, asshown in Fig. 2(d). The test for this specimen was con-ducted in the SEM and imaged using an acceleratingvoltage of 20 kV and a backscattered electron (BSE) de-tector. The data shown in Fig. 3 illustrate that the fa-tigue performance of this specimen exceeds the fatiguebehavior of typical laboratory-scale fatigue specimenstested at similar stress levels. These differences can be

attributed to specimen size scale effects and differences

in testing procedures[22]. However, it is clear that sliplines are initiated and continue to intensify with addi-tional fatigue cycling, which is consistent with the be-havior of more traditional specimens. Improvedmethods to perform dynamic system calibration arecurrently being evaluated and implemented into thetesting methodology.

Microscale fatigue specimens are also amenable tocharacterization via electron backscattered diffraction(EBSD). EBSD data provide the identification of spe-cific slip systems that were activated in individualphase constituents. Figure 4 illustrates an example of amicroscale specimen tested in tension that was charac-terized using this approach. It is clear from close ob-

Fig. 2 BSE micrograph of the test specimen: (a) Microscale fatigue specimen,(b) onset of localized slip activity, and (c) and (d) continued slip intensification asadditional blocks of 107 cycles were applied at increasingly higher stresses. Slipband development is highlighted by yellow arrows in (c).

Fig. 3 Microscale fatigue data of Ti-6Al-2Sn-4Zr-6Mo samples overlaid withdata from conventional laboratory scale specimens. The red squares and greentriangles represent data obtained from the in-situ microspecimen testing technique. Adapted from [22].

(a)

(b) (c) (d)

10 m

5 m

max = 860 MPa

N = 107 cycles

max = 920 MPa

N = 107 cycles

max = 980 MPa

N = 107 cycles

104 105 106 107 108 109 1010

Cycles to failure (Nf)

Bulk yield strength

20 Hz Conventional20 kHz Conventional20 kHz Runout100 Hz Microspecimen1 Hz Microspecimen

1200

1100

1000

900

800

700

600

500

400

m

ax

(MP

a)


servation that most of the slip lines in this specimen(identified in the figure by yellow dotted lines) arealigned with the basal planes of the p grain. A Hikaricamera within an FEI/PhillipsXL-30FEG-SEM oper-ating at 20 kV, 50 nA, with EDAX-TSL software usinga 0.1 m step size captured the image. There is no ap-parent activation of localized slip elsewhere withinthe fatigue specimen.

The small size of the microscalespecimens allows their microstruc-ture to be fully analyzed using a 3D-EBSD serial sectioning proce-

dure[17-19]. This allows the explicit3D microstructure to be input intoa CPFEM framework. Figure 5 is a3D reconstruction of the physicalmicroscale tensile specimen shownin Fig. 4. An FEI Nova 600 DualBeam FIB-SEM equipped with ahigh speed Hikari EBSD camerawas used to conduct the serial sec-tioning process.An ion beam with an accelerat-

ing voltage of 30 kV and a currentof 9.5 nA was used to mill 100-nm-thick slices in cross-section. The

cross-section faces were subsequently cleanedusing a 5-kV accelerating voltage to remove sur-

face damage[23] and improve the quality of theEBSD patterns. EBSD data acquisition was con-ducted with an electron beam at an acceleratingvoltage of 30 kV, current of 5nA, and square gridwith 0.15 micron step size. The entire 3D-EBSDdata collection procedure was automated using

Fig. 4 EBSDcharacterization of a

microscale specimen

illustrating (a) the orientation of slip

lines, (b) the prismplane trace, and

(c) the basal planetrace.

Fig. 5 3D reconstruction of a microscale fatigue specimen,where color represents crystallographic orientation relativeto the tensile axis.

Slip lines Prism pl trace Basal pl trace

10 m 10 m 10 m

1010

0001 2110


custom scripts. A total of 400 slices were analyzed

and reconstructed using DREAM.3D software[24].Tools are being developed and refined to inter-

rogate these microstructural volumes and inte-grate results with other experimental techniquesincluding digital image correlation. These resultsare anticipated to permit calibration of the crystalplasticity models to actual measured material response, and therefore enable more accurate prediction of mechanical response through simulation.

For more information: Jaimie S. Tiley is senior materi-als engineer, U.S. Air Force Research Laboratory, 223010th St., Dayton, OH 45433-7816, 937/255-5347,[email protected], www.wpafb.af.mil.

References

1. U.S. Air Force. MIL-HDBK-1783B (w/change), De-partment of Defense Handbook: Engine Structural In-tegrity Program, 2004.2. S.K. Jha, et al., Scripta Mater., Vol 48, p 163742.3. S.K. Jha, M.J. Caton, and J.M. Larsen, Mater. Sci. Eng.A, 468470:2332, 2007.4. J.M. Larsen, et al., Int. J. Fatigue, Article in Press.5. S.K. Jha and J.M. Larsen, 4th Intl. Conference on VeryHigh Cycle Fatigue, VHCF-4, Ann Arbor, Mich., p38596, 2007.

6. C.J. Szczepanski, et al., Metall. Mater. Trans. A,39:284151, 2008.7. A.L. Pilchak, R.E.A. Williams, and J.C. Williams,Metall. Mater. Trans. A, 41A:10624, 2010.8. I. Bantounas, D. Dye, and T.C. Lindley, Acta Mater.,57:358495, 2009.9. F. Bridier, P. Villechaise, and J. Mendez, Acta Mater.,56:395162, 2008.10. S.K. Jha, et al., Int. J. Fatigue, 42:24857, 2012.11. M.D. Uchic, Science, 305: 986-989, 2004.12. M.D. Uchic and D.M. Dimiduk, Mater. Sci. Eng. A,400401:268278, 2005.13. M.D. Uchic, et al., Scripta Mater., Vol 54, p 759-764.14. J. Michler, et al., Appl. Phys. Lett., 90, 043123, 2007.15. D. Kiener, et al., Acta Mater., 56:580-592, 2008.16. J.Y. Kim and J.R. Greer, Acta Mater., 57:5245-5253,2009.17. M.D. Uchic, et al., Scripta Mater., Vol 55, p 23-28.18. M.A. Groeber, et al., Mater. Charact., 57:259273,2006.19. N. Zaafarani, et al., Acta Mater., 54:1863-1876,2006.20. P.A. Shade, et al., Acta Mater., 57:45807, 2009.21. R. Wheeler, P.A. Shade, and M.D. Uchic, JOM,64:58-65, 2012.22. C.J. Szczepanski, et al., Int. J. Fatigue, 2012.23. A. Genc, et al., Microsc. Microanal., Vol 13 (suppl.2), p 1520-1521.24. DREAM.3D [http://dream3d.bluequartz.net/].


1964 1965 1966 1967 1968

Celebrating ASMs First 100 Years in Supporting Materials InnovationAs we celebrate the 100-year anniversary of ASM International (1913-2013), we look at the many notable advancements in materials andprocesses technology that occurred along the way. ASM has played a significant role in this by providing a forum for bringing togetherengineers, scientists, and practitioners to exchange information on these advancements, and by disseminating information about them tothe engineering community in general. The society, which began in 1913 as the Steel Treaters Club, also went through several changes overthe years to its present ASM International. In each issue of AM&P in 2013, we are highlighting in 10-year increments significant advancementsin technology, as well as advancements in the society.

ASM Mobile Metallography LabASMs mobile lab and first hands-onmetallography course were unveiledat the New York Metal Show. By1964, ASMs Metals EngineeringInstitute was operating for six years,presenting courses to more than8000 students and issuing 6000certificates.

Stainless steel replacements

for vehicle exhaust systems are

launched into the U.S. automotive

market.

Materials Applications News for Design &Manufacturing, a quarterly publication, is introduced

along with Metals/Materials Today, a monthly technicalnews magazine replacing Metals Review.

Volume 2 of theMetals Handbook is

published: HeatTreating, Cleaning, andFinishing is nearly 700pages long, written by45 author committees

and more than 700contributors.

Metal Science KitThe ASM EducationCommittee devised a kit ofmaterials and aninstructional booklet thatwould be most helpful to

the young man who isinterested in metalsand perhaps isthinking of metallurgyas a career. Costing$30, kit contains 108experiments and afurnace to heatspecimens as large as8.25 4 in.

Gateway Arch debutsEero Saarinen (1910-1961), thefamed Finnish-American architect,won a contest in 1946 to design amonument for the Jefferson NationalMemorial in St. Louis. His archconsists of hollow triangular legsthat gradually decrease in size as itrises. Saarinen chose stainless steelas the cladding material because hewanted it to last for a thousandyears. The monument measures630 ft tall 630 ft wide at the base.

Metals Abstract is launched, a newjournal resulting from the merger ofASMs Review of Metal Literatureand IOMs Metallurgical Abstracts.

ASTM Committee E-28 onMechanical Testing is organized.

One of the first colorphotos printed in MetalProgress appears in anarticle titled A Decadeof Improvements inGenerator RotorForgings. It shows thelargest ingot everproduced at the U.S.Steel HomesteadWorks. Vital statistics:657,000 lb, 17 ft tall,and more than 11 ft indiameter.

ASM considers adding aCenter for ContinuingEducation at Metals Park.The Board of Trusteeshas approved the conceptof further development ofMetals Park to be ofmaximum benefit to theASM member, and to theengineering and scientificcommunity.


1969 1970 1971 1972 1973

The 64-story U.S.Steel Tower in

Pittsburgh debuts asthe companys

headquarters, as wellas a showpiece for

one of theirproducts, COR-TENsteel. The weather-

resistant steeldevelops a tightly-

adhering brownoxide coating that

never needspainting. However,the metal had the

unwelcome effect ofstaining nearbysidewalks and

buildings with rustthat was difficult to

remove.

Neil Armstrongbecomes the firstman to walk on theMoon on July 20,1969. The LunarExcursion Module is shown in thebackground. Three astronautstraveled to the Moonon the ColumbiaCommand Moduleafter blasting off the Earth on a Saturn 5 rocket.

Wrought ironproduction ceasesThe closing of the A.

M. Byers Company ofAmbridge, Pa., marks

the end of wroughtiron production in

North America. TheASTM Committee A-2

on Wrought Iron,organized in 1905,disbands in 1970.

F. Kenneth Iverson takes over at Nuclear Corp.to create the first steel mini-mill, making bars

starting with steel scrap melted in an electric arcfurnace. His plant in rural Darlington, S.C., hires

nonunion farmers, salesmen, and sharecroppers.Iverson branches into sheet steel production, in

direct competition with Big Steel and one of theirmost lucrative products. Nucor becomes the

second-largestU.S. steel

manufacturerwhile launchingan entire mini-

mill industry.

First electric arc steelmaking furnace in theWestern Hemisphere, and ASMs first NationalHistoric Landmark. Dedicated at ColtIndustries Crucible Specialty Metals Division,Syracuse, N.Y. The furnace now stands atPittsburghs Station Square.

Harry Chandler becomes editor ofMetal Progress, a position he will holdthrough 1985. Chandler also authored how-to books for ASM, including the classic Metallurgy for the Non-Metallurgist. Prior to joining ASM, he served for nearly five years in the U.S. Marine Corps, earned a M.A. in journalism, and worked for several other publications, including Penton Publishings Steel.

The first class ofASM Fellows, 200strong, is installedat ceremonies atMetals Park. ASMestablished thehonor of Fellow ofASM to recognizemembers fordistinguishedcontributions tomaterials scienceand engineering.

The National Congresson Technology for

Productivity was developedfor the 1971 Metal Show.

Twenty-three of the nations leading technicalsocieties and associations

cooperated in thepreparation of close to 40

separate sessions.

Dr. Taylor Lyman (1917-1973)Lyman was the editor and driving force behindthe Metals Handbookseries. Dr. Taylor Lymanwas a man of tremendousintellectual proportion. His encyclopedic mind and his genius in theorganization of knowledge have given the technical world the Metals Handbook. His towering knowledge ofmetals was not limited to theUnited States, but extended to the Western Hemisphere and the world itself, notes ASM Director Allan Putnam in tribute.


Singing the praises of brass

From an advertisement for The American Brass Company, Metal

Progress, March 1945

Remember your introduction to Brass? As a boy perhaps, in a

manual training classor possibly on the bench of your home

workshop. Wherever it was, you realized then that the yellow

metal was not only royal in appearance, but that it was a

workable metal, too.

It seems that Brass was especially made to be machined and

worked and formed into so many useful things that people

needthanks to copper-alloy metallurgy that has developed a

variety of Brasses with properties that manufacturers find so

indispensable: Brasses that can be worked hot or cold, that

can be forged, rolled, spun, stamped,

pressed, coined, upset or drawn; Leaded

Brasses that machine at top spindle

speedsductile Brasses that could be

formed or shaped with the pressure of your

fingersor hard spring Brasses that can

be stressed through millions of cycles

without danger of failure by fatigue.

pastimes

Sara is weld-formedfrom strips of COR-TEN steel.

Selected items from the pages of ASM Internationals monthly magazine: Metal Progress was published from 1930 to

1986, after which Advanced Materials & Processes came into being.

Admiring the beauty

of steel

From an advertisement for COR-

TEN steel from U.S. Steel, Metal

Progress, September 1972

Her name is Sara. Five foot four,

154 pounds, and if exposed to the

weather is destined to grow more

beautiful with age. Sara is the work of

sculptor Charles Park, Hockessin,

Delaware, who weld-formed her from

strips of COR-TEN Steel. Sculptors

are using USS COR-TEN Steel for

its strength, low cost, natural beauty

and its built-in durability, the same

qualities that make it so attractive to

designers. Exposed to the weather,

USS COR-TEN Steel forms a dense

protective oxide film thats self-

maintaining. Its handsome russet color

grows progressively deeper and richer.

Surface scratches heal themselves.

COR-TEN Steel is strong too, it can be

obtained in minimum yield points as high

as 50,000 psi, in thicknesses through 4 in.,

and as high as 60

welding and materials-at a glance06,07,2013

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