The ULTIMATE Choice

EXCEPTIONAL CHARACTERISTICS FOSTER A RANGE OF COMMON APPLICATIONS

INTRODUCTIONTitanium — Coming of AgeExamining the Benefits 2

Maximum PerformancePerformance-to-CostLife Cycle CostTotal Design

TITANIUM’S PROPERTIESA Unique Set of CharacteristicsCreates Intrinsic Value 3-5

Exceptional Strength-to-Weight RatioLow DensityExcellent, Natural Corrosion ResistanceSuperior Erosion ResistanceHigh Operational Thermal ConductivityLow Modulus of ElasticityLow Coefficient of ExpansionNon-MagneticBiocompatibleExtremely Short Half-LifeDramatic AppearanceEnvironmentally Friendly

APPLICATIONS FOR TITANIUMAn Expansive — and Expanding —Scope of UsesAerospace: Titanium’s First andForemost Role 6-7

Gas Turbine EnginesAirframesSpace StructuresThick Section Titanium

Industry: Suitability for a Wide Arrayof Applications 7-10

Heat ExchangersPower GenerationChemical ProcessingOffshore Oil and GasDownhole Oil and GasPetroleum ProcessingMarine ApplicationsDesalinationArmor/ArmamentMetal Recovery and FinishingChlor-Alkali ProcessingPulp and PaperFlue Gas Desulphurization

Industry: Suitability for a WideArray of Applications (cont.) 10

Food and PharmaceuticalNuclear Waste StorageHigh TechnologyMetal Matrix CompositesTitanium AluminidesFerro-TitaniumOther Industrial Applications

Commercial and Consumer: AddingValue in Hundreds of Common Uses 11

Sporting GoodsConsumer GoodsMedicineArchitecture/ConstructionAutomotive

THE STORY OF TITANIUMA Historical Perspective 12-13

The Early Years: Prior to 1930The Kroll Era: The 1930’s - 1949The Aerospace Years: 1950 - 1980The Diversification Years: 1970 - 1995The Present

PRODUCING TITANIUMFrom Black Sand to a Rangeof Products 14-16

Extracting Titanium From the OreMelting to Ingot: Vacuum Arc

Remelting and Cold Hearth MeltingTypical Production Flow ChartDiverse Mill Products For Multiple UsesCasting: Efficient Production of

Near Net ShapesPowder Metallurgy: A Promise of

Lower Cost and Wider Uses

FABRICATING TITANIUMConventional Techniques from theStraightforward to the Sophisticated 17

THE METALLURGY OF TITANIUMThe Alpha and Beta Forms ofTitanium and Its Alloys 18

Common Titanium Terminology 19

TABLE OF CONTENTS Page Page

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The ULTIMATE Choice

Titanium, once considered an exotic, expensivemetal suited exclusively to aerospace use, hascome of age as a versatile metal for numerouseveryday applications, due to its uniquemetallurgical properties, abundant availability,low life cycle cost and ease of fabrication. Itis now commonplace not only in aircraft,but in industries including chemical andpetrochemical processing, offshore oil andgas, marine and desalination, as well as incommercial and consumer uses ranging fromgolf clubs to medical implants and architecture.

Examining the BenefitsWhy are engineers, purchasing managers,fabricators, maintenance directors, andmanagement turning to titanium to addresstheir myriad design, performance and financialchallenges? There are four related reasonsto consider the metal and its alloys for anygiven application:

Maximum PerformanceMany items, such as jet engine fan blades andmedical implants, simply perform best whenmanufactured of titanium, due to the metal’sunique combination of mechanical andphysical properties.

Performance-to-CostIn some cases, titanium enhances an item’sperformance so dramatically it is wortha higher cost than another material. Forexample, recreational products like golfclubs offer a playing experience that’s wortha higher price; on an automobile, titaniumconnecting rods save enough weight toimprove performance without adding acostly turbocharger.

Life Cycle CostIn chemical processing and marine environ-ments, for example, the initial higher costof titanium pipe, fittings and tubing can beregained several fold by the savings that resultfrom its long (many times unlimited) life anda corresponding reduction in equipmentmaintenance and process downtime.

Total DesignIn some situations, the use of titanium canallow other parts of the complete system to bebuilt more simply and cheaply. For example,on semi-submersible oil and gas offshoreplatforms, lighter weight titanium riser pipecan substantially reduce the required size andweight of platform structure, riser interfaceand peripheral components, thereby reducingthe overall project cost.

In each case, it is a combination of titanium’sphysical characteristics, such as strength, lightweight and corrosion resistance, that impartsa synergy of benefits to the end application.Furthermore, a natural abundance of the oreand new, more efficient production methodshave made titanium more consistently availableand affordable than ever before.

Titanium — Coming of AgeINTRODUCTION

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The ULTIMATE Choice

Titanium’s accelerating usage is attributable toits remarkable and distinctive combination ofphysical and metallurgical properties. The keyto best utilizing titanium is to exploit thesecharacteristics, especially as they complement oneanother in a given application, rather than to justdirectly substitute titanium for another metal.

Exceptional Strength-to-Weight RatioTitanium’s excellent tensile and yield strengthcombined with its low density results in thehighest strength-to-weight ratio of any oftoday’s structural metals. Especially when it isalloyed, titanium is as strong as steel, yet itsspecific gravity is only 56% that of steel. Thisis a prime advantage for its use in aerospace,of course, and also for such diverse applicationsas deepwell tubing strings and offshore risersin the petroleum industry, surgical implants,and golf club heads.

TITANIUM’S PROPERTIES

A Unique Set of Characteristics Creates Intrinsic ValueTitanium’s yield strengths range from 25,000psi (172 MPa) for commercially pure (CP) Grade1 to above 200,000 psi (1380 MPa) for heattreated beta alloys. The densities of titanium-based alloys range between .160 lb/in3

(4.43 g/cm3) and .175 lb/in3 (4.85 g/cm3).

Low DensityTitanium’s low density, roughly 56% that ofstainless steels and half that of copper andnickel alloys, means greater metal volumeper pound compared to other materials.

In conjunction with its strength, this oftenmeans components can be made smaller and/or lighter. This is the basis for many aerospaceapplications, and also for rotating or recipro-cating components such as centrifuges, pumpsand automotive valves and connecting rods.

Titanium’s low density, combined with itsnatural corrosion resistance, also gives itadvantages over other materials in aggressiveenvironments. Based on its strength and thefact it needs no corrosion allowance, it can bespecified in thinner cross-sections, using lessmetal per unit of area. On a dimensional orper-piece basis, thiseffectively offsets itshigher per-pound cost,especially when life cyclecosts are also considered.Based on this, downholeoil and geothermal wellproduction tubulars andlogging tools are beingproduced from titaniumalloys. In marine service,pleasure boat components,naval surface ships andsubmarine cooling watersystems are growingmarkets for titanium,driven by its lightweight and immunityto seawater corrosion.

Strength-to-Weight Ratios of Structural Metals

ksiSource: International Titanium Association (ITA) Source: ITA

Densities ofVarious Metals

g/cm

3

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The ULTIMATE Choice

Chlorine and Other Halides

! Fully resistant to moist chlorine andits compounds.

! Fully resistant to solutions of chlorites,hypochlorites, perchlorates and chlorinedioxide.

! Resistance to moist bromine gas,iodine and their compounds is similarto chlorine resistance.

Water

! Immune to corrosion in all natural,sea, brackish and polluted waters.

! Immune to MicrobiologicallyInfluenced Corrosion (MIC).

Oxidizing Mineral Acids

! Highly resistant to nitric, chromic,perchloric and hypochlorous (wetchlorine gas) acids.

Gases

! Corrosion resistant to sulfur dioxide,ammonium, carbon dioxide, carbonmonoxide, hydrogen sulfide andnitrogen.

Inorganic Salt Solutions

! Highly resistant to chlorides ofsodium, potassium, magnesium,calcium, copper, iron, ammonia,manganese and nickel.

! Highly resistant to bromide salts.

! Highly resistant to sulfides, sulfates,carbonates, nitrates, chlorates andhypochlorites.

Organic Acids

! Generally very resistant to acetic,terephthalic, adipic, citric, formic,lactic, stearic, tartaric and tannicacids.

Organic Chemicals

! Corrosion resistant in organic processstreams of alcohols, aldehydes,esters, ketones and hydrocarbons,with air or moisture.

Alkaline Media

! Low corrosion rates in hydroxidesof sodium, potassium, calcium,magnesium and ammonia.

TITANIUM’S PROPERTIES

Corrosive Environments Where Titanium’s Oxide Film Provides Resistance

Excellent, Natural Corrosion ResistanceTitanium is a reactive metal, meaning itspontaneously forms a natural oxide film(mainly TiO2) in the presence of any oxygen.Whenever there is any amount of air or waterin a process stream or environment, the oxidefilm forms and protects the metal fromcorrosive attack. If the film is scratched ordamaged, it repairs itself instantly. Thehighly-adherent film is exceptionally resistantto a broad range of acids and alkalis, aswell as natural, salt and polluted waters.Titanium’s corrosion resistance together withits low density, high strength and erosionresistance, make it ideal for numerouschemical processing and marine uses,as well as architectural applications.

Information provided as an overview. Before specifying titanium in any aggressive environment, consult corrosion experts. Adapted from“Shedding New Light on Titanium in CPI Construction,” by James S. Grauman and Brent Willey, Chemical Engineering, August 1998.

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The ULTIMATE Choice

In contrast to piping and heat exchangersmade from copper-based alloys, equipmentmade from titanium can be designed for highflow velocities without detrimental effects fromturbulence, impingement or cavitation. Thiserosion/corrosion resistance combined withlow density has made titanium alloys primematerials for fluid flow components inchemical and power plants and marine/navalapplications. Titanium optimizes heat transferefficiency, minimizes tube/piping size and wallthickness requirements, improves equipmentreliability and reduces life cycle costs. Applica-tions are as diverse as ship superstructures,service water, firemain and weapons systems,exhaust uptakes, launch systems, jet blastdeflectors and ventilation ducting.

High Operational Thermal ConductivityUnder in-service conditions, titanium’s heattransfer efficiency approximates that ofadmiralty brass and copper-nickel, andsurpasses that of stainless steel. Titanium’shigher strength permits the use of thinnerwalled pipe, tubing and equipment; the oxidefilm keeps the surface bright, smooth andresistant to higher fluid flow velocities.

Low Modulus of ElasticityTitanium’s low modulus means excellentflexibility and strong springback characteristics.This promotes its use in various springs foraircraft and valves, where a modulus half thatof steel, but a strength equivalent to steelallows a titanium spring to be half as large andheavy. This property also benefits auto parts

(which must absorb shock), medical implants(that must move with the body), architecture(where roofs must resist hail), and recreationalgear (golf clubs, tennis racquets, mountainbikes and skis).

Low Coefficient of ExpansionTitanium’s coefficient of expansion is signifi-cantly less than ferrous alloys, copper-nickelalloys, brass and many stainless steels, makingit much more compatible with ceramic andglass materials than most metals. This contrib-utes to its architectural utility, particularly whenmetal-to-ceramic/glass seals are involved.

Non-MagneticTitanium is virtually non-magnetic, making itideal for applications where electro-magneticinterference must be minimized, such aselectronic equipment housing and downholewell logging tools. It also contributes totitanium’s role in human body implants, wherea magnetic metal could be subject to outsideinterference.

BiocompatibleTitanium is non-allergenic and non-toxic toliving tissues. Together with its natural resis-tance to bodily fluids and low modulus, aswell as non-magnetic properties, this makestitanium the most biocompatible of all metals,and leads to its use for prosthetics and implants.

Extremely Short Half-LifeIn contrast to many ferrous alloys, titaniumalloys do not contain a significant amount ofelements which may become radioactive forlong periods of time. This permits the use oftitanium in nuclear systems.

Dramatic AppearanceTitanium’s distinctive, striking beauty resultsfrom its oxide film, which absorbs, refracts andreflects light, creating interference that givestitanium its color. The film thickness can beincreased by anodic oxidation to vary the color.The metal’s surface texture can also be varied.These traits enhance titanium’s value inarchitecture, jewelry and even bicycles.

Environmentally FriendlyTitanium is made from an abundant naturalresource which is mined with minimal impact.Its production generates no harmful by-products and 95% of its scrap can be recycledinto titanium or ferro-titanium products.

TITANIUM’S PROPERTIES

Corrosion Rates of Alloy Erosion-Corrosion ResistanceSource: ITA

Superior Erosion ResistanceTitanium’s oxide film also provides superiorresistance to abrasion, erosion, erosion-corrosion,cavitation and impingement attack in high velocityprocess streams. It is up to twenty times moreerosion resistant than copper-nickel alloys.

Erosion-Corrosion Resistance to Seawater

- 7

- 4

- 4

- 4

- 4

- 4

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The ULTIMATE Choice

An Expansive — and Expanding — Scope of UsesTitanium and its alloys have proven to betechnically superior, cost-effective constructionmaterials for a wide variety of aerospace,industrial and commercial applications. InNorth America, approximately 60% of thetitanium manufactured is utilized in aerospace.Due to the expansion of existing industrialapplications, the greatest growth is expectedto occur in the chemical processing, marine,desalination, medical and architectural sectors.The continued development of newer titaniummarkets, such as armor/armament and auto-motive will help drive the titanium industry inthe new millennium.

Aerospace: Titanium’s First andForemost ApplicationTitanium’s metallurgical and physical character-istics and the requirements of aerospacemanufacturers are so congruous that growth ofthe metal and these industries has been closelyintertwined. The aerospace market for titaniumincludes commercial (and smaller private)aircraft, military aircraft (small fighters,large transports, missiles) and spacecraft.

Selection of titaniumfor both airframes andengines is based uponits specific properties:weight reduction (dueto the high strength-to-weight ratio),coupled with exem-plary reliability thatis attributable to itsoutstanding corrosionresistance andmechanical properties.

The percentage oftitanium used inaircraft increases witheach design genera-tion. In military craft,today’s F-15 is 26%titanium, compared to the 1960’s F4, which was9% titanium by weight. The F-22 design callsfor 39% titanium by weight. (The military’s SR-71 was made 90% from titanium and still holdsall speed and altitude records.) In commercialcraft, not only is there a greater percentage oftitanium being used per plane, but larger planesrequire a greater total amount of titanium.

The Boeing 777 uses nearly 50 tons oftitanium, and, of course, many more ofthese will be built than any military aircraft.

Gas Turbine EnginesThe largest single use of titanium is in jetengines, where titanium alloy parts make up20% to 30% of the weight, primarily in thecompressor.

These highly efficient engines are possiblethrough the use of titanium alloy componentslike fan blades, compressor blades, rotors,discs, hubs and numerous non-rotor partslike inlet guide vanes. Titanium is the mostcommon material for engine parts that operateup to 1100oF (593oC), because of its strengthand ability to tolerate the moderate tempera-tures in the cooler parts of the engine. Otherkey advantages of titanium-based alloysinclude light weight (which translates to fueleconomy), and good resistance to creepand fatigue. The development of titaniumaluminides should allow the use of titanium inhotter sections of a new generation of engines.

Recent advances in titanium production forengines include the use of cold hearth meltingto cost-effectively produce ultraclean alloys;the fabrication of titanium wide chord fanblades that increase efficiency and reducenoise; and the casting of large, intricate engineparts and cases that reduce assembly time.

APPLICATIONS FOR TITANIUM

Source: Boeing Commercial Airplane Group

Titanium Usage on Boeing Aircraft

Year of Roll-out

Perc

ent

Tita

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atin

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The ULTIMATE Choice

AirframesTitanium alloys effectively compete withaluminum, nickel and ferrous alloys in bothcommercial and military airframes. Applicationsrun the gamut of airframe structural members— from massive, highly-stressed, forged wingstructures, to critical small fasteners, springsand hydraulic tubing.

Titanium alloys now replace nickel and steelalloys in nacelles and landing gear componentsin the Boeing 777. Investment casting tech-niques allow complex shapes to be made atrelatively low cost. (For example, heat shieldsthat protect wing components from engineexhaust are cast of titanium.) Cold hearthmelting excels at producing clean metal forstructural applications while controlling costs.Superplastic forming/diffusion bonding andpowder metallurgy have helped to increase theuse of titanium alloys in new airframe designs,by lowering the cost of machining and theamount of waste.

Space StructuresStarting with the extensive use of titaniumin the early Mercury and Apollo space craft,titanium alloys have been widely used inmilitary and NASA space applications. TheSpace Shuttle uses titanium alloys for diffusionbonded members in the thrust structure, aswell as for pressure vessels, hydraulic tubingand the vertical stabilizer. In addition tomanned space craft, titanium alloys areextensively employed in solid rocket boostercases, guidance control pressure vessels and awide variety of applications demanding lightweight and reliability.

Thick Section TitaniumThick section size in aerospace is generallydefined as forged or rolled product with athickness that exceeds four inches. Titaniumalloys offer a useful, and in many casessuperior, alternative to steel alloys for thicksection application. They demonstrate superiorfatigue and fracture toughness properties, bothin the absolute sense and from the standpointof uniformity throughout the section thickness,even as thickness increases from 4” to 6” to8”. Thick section titanium alloys have beensuccessfully used in airframe parts and inrotating components such as fan disks for PWAand GE high bypass jet engines and Sikorskyhelicopter rotor forgings.

Industry: Suitability For a WideArray of ApplicationsTitanium’s utility in industry is primarily dueto its exceptional corrosion resistance, whichallows designers to specify it with no corrosionallowance and allows plants to reducemaintenance to improve life cycle costing.Commercially pure (CP) grades are the mostoften used, with CP Grade 2 by far the mostcommon in industrial applications.

Heat ExchangersTitanium’s properties, in particular its virtualimmunity to corrosion in salt, brackish orpolluted waters, lead to extremely reliable,highly efficient, cost competitive heatexchangers. Not only are initial costs fortitanium attractive relative to other metals, butlife cycle costs are lower because maintenanceis reduced. Titanium is readily available inwelded and seamless tubing in many alloygrades for shell/tube exchangers, or in pressedform for plate and frame exchangers.

In power plants, refineries, air conditioningsystems, chemical plants, offshore platforms,surface ships and submarines, titanium’s lifespan and dependability are proven. In fact,with over 300 million feet of welded titaniumtubing in power plant condenser service,there have been no reported failures dueto corrosion.

Based on its outstanding natural resistance tocorrosion and erosion-corrosion, titanium canbe specified for heat transfer tubing with azero corrosion allowance which, with its goodstrength, permits use of very thin walls. Thisreduces exchanger size, weight and materialrequirements and minimizes total cost. In fact,titanium can be comparable in initial cost tocertain copper or stainless steel alloys.

Thinner walls coupled with its surface charac-teristics promote excellent heat transfer.Titanium’s hard, smooth surface accepts veryhigh fluid flow rates and minimizes buildup ofexternal fouling films which can rob metalsof heat transfer efficiency. Although copper-based alloys possess higher thermal conductivityand overall heat transfer coefficients whennew and clean, titanium exhibits higher long-term operating coefficients in actual service.

APPLICATIONS FOR TITANIUM

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The ULTIMATE Choice

It is not unusual to observe a 95-100%cleanliness factor for titanium in many services.Although it’s not biotoxic, biofouling can besuccessfully controlled by periodic chlorinationand/or mechanical means (“bullets,” tubebrushes and sponge balls). A fouling factorof 0.0005 is easily achieved for titanium inseawater using these strategies.

Titanium is also unique in its ability to promotedropwise condensation on its surface. Mostmetals form continuous surface films ofcondensate when condensing water vaporin evaporative processes. This is not nearlyas efficient as titanium’s dropwise mechanismfor brine and nitric acid distillation.

Power GenerationSteam turbine failure has historically accountedfor over 30% of the downtime of power plants.The use of Ti-6Al-4V for turbine blades hasbeen proven to increase the efficiency and lifeof low pressure steam turbines while decreasingdowntime and maintenance. CP titanium thinwall condenser tubing is used extensively inpower plants, because it can be specified

without a corrosion allowance and has avirtually unlimited life, well past the life of thecondenser or plant. In nuclear power stations,the availability and declining cost of seamwelded titanium tubing has led to an increasein its use.

Chemical ProcessingIn many corrosive process environments,titanium proves to be the most economicalsolution. Its natural corrosion resistance helpsmaximize equipment life, reduce downtime andimprove overall plant performance. Hearthmelting is now used to economically producehigh quality titanium from nearly any mix ofraw material and titanium scrap. Fabricationand welding are well understood. Today, theupfront cost of the metal and its fabrication arehighly competitive with other materials, and lifecycle costing often gives titanium the edge in acost/performance analysis. It is commonly usedfor heat exchangers, vessels, tanks, agitatorsand piping systems in the processing ofaggressive acidic compounds, as well asinhibited reducing acids and hydrogen sulfide.

Offshore Oil and GasTitanium’s seawater corrosion resistance, lightweight, high strength and low modulus make itideal for a variety of applications in offshore oiland gas exploration and production. Topside,titanium tubing and pipe is used extensively infiremain and service water systems, because iteliminates difficult, expensive offshore mainte-nance, repairs and replacement. Its highstrength-to-weight ratio and low modulusmake it well suited for dynamic production anddrilling riser systems, where every pound ofweight saved below the surface also savesthree to five pounds on the platform andanchoring system. High operating pressures,temperatures, and sour environments also favortitanium risers over traditional metallic/rubbercomposites. With its low modulus, titanium isalso used for stress joints, to accommodateplatform movement. Because titanium is non-magnetic and seawater corrosion immune, it isideal for seismic array and downhole welllogging components. As deeper reservoirs areexplored and higher temperature oil and gasare recovered, titanium’s role offshore shouldcontinue to expand, and the industry has thecapacity and fabrication capabilities to meetthe demand.

APPLICATIONS FOR TITANIUM

Heat Transfer Rate of Tubes used ina Model Condenser for Six Months

Coolant velocity (m/s)

Source: Japan Titanium Society

Hea

t tr

ansf

er c

oef

fici

ent

(Kca

l/m2

°Ch

)

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The ULTIMATE Choice

Downhole Oil and GasIn deep sour gas well applications, theexceptional resistance of titanium alloys toattack from H

2S, CO

2, and chloride-rich brines,

combined with high strength and low density,make them especially attractive for applicationssuch as packers, tubing strings, liners, safetyvalves and springs. Numerous titanium alloysare approved for sour service under the NACEMR-01-75 standard and for sour brine servicetemperatures in excess of 250oC.

Petroleum ProcessingThe need for longer equipment life, coupledwith requirements for reduced downtime andmaintenance, favor the use of titanium in heatexchangers, vessels, columns and piping systemsin refineries and liquid natural gas plants. It isimmune to general attack and stress corrosioncracking from hydrocarbons, H

2S, CO

2,

ammonia and chloride brines.

Marine ApplicationsTitanium provides an idealsolution to the problems thathave traditionally characterizedseawater applications. It isunsurpassed in corrosion immunityfor marine service and is notsubject to pitting, crevicecorrosion, stress corrosioncracking or microbiologicallyinfluenced corrosion in naturalseawater. Coupled with its lowdensity, high strength and erosion resistance,this means unexcelled performance in termsof service life, weight savings and reducedmaintenance costs for the marine designengineer. In fact, titanium performs so wellthat producers can offer warranties as long as100 years in certain seawater applications.

Beyond its metallurgical characteristics, itsavailability, low life cycle cost and ease offabrication make titanium a prime candidatefor ship propellers, shipboard heat exhangers,piping systems, and ballast, waste, drain andsprinkling systems. It is also being used oneverything from ferries and fishing boats,to naval ships, deep sea submersibles andsubmarines. A titanium commercial ship hullhas been built and tested, and although itsinitial cost is higher than a conventional hull,its long life, lower maintenance costs, andreduced fuel consumption could make it morecost-effective over the life of the ship.

DesalinationExcellent resistance to corrosion/erosion andhigh condensation efficiency make titanium themost dependable material for critical segmentsof multi-stage evaporation desalination plants.Because welded titanium condenser tubingcan be thin-walled, it is cost-competitive withcopper-nickel, which it far surpasses in life.It is also used in the rejection, heat recoveryand heat input stages.

Armor/ArmamentThe application of titanium in ballistic armoris focused on two areas: armored vehicles andordnance, and personal armor. On tanksand ground vehicles, titanium reduces weightto enhance airlift transportability and fightingforce mobility. In comparison to traditionalrolled homogenous armor, titanium offersan excellent strength-to-weight ratio, goodballistic properties and multi-hit capacity,

corrosion resistance andweldability/machinability.In addition to hull armor,titanium is used for turrets,hatches and suspensions,which, when made of steel,can account for over 50% ofa tank’s weight. Titanium isalso being used in field guns,notably the UltralightweightField Howitzer. In personalarmor, titanium’s toughness,light weight and low modulus

combine to offer protection with less discomfort.Vests generally are comprised of titanium panelsbacked by other materials, so the role of thetitanium and its ballistic requirements can vary.

Metal Recovery and FinishingHydrometallurgical extraction of metals fromores in titanium reactors is an environmentallysafe alternative to smelting. Extended lifespan,increased energy efficiency and greater productpurity are promoting the use of titaniumelectrodes in electro-winning and electro-refiningof metals like copper, gold, manganese andmanganese dioxide.

Chlor-Alkali ProcessingThe unique electrochemical properties oftitanium make it the most energy efficientchoice for dimensional stable anodes (DSA’s)used for the production of chlorine, chlorateand hypochlorite.

APPLICATIONS FOR TITANIUM

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The ULTIMATE Choice

addition of ceramic or intermetallic compoundsin fiber or particulate form to produce proper-ties beyond those achieved by alloying alone.Current developments using SiC fiber reinforce-ments could permit titanium base compositesto replace nickel and steel alloys in highertemperature and higher modulus applications.

Titanium AluminidesThis class of materials, typically with titanium-aluminum ratios of 1:1 to 1:3, represents thenext generation of alloys intended to push theapplications of titanium beyond the traditional1100oF barrier. Two types of aluminides arecurrently under investigation. The alpha 2aluminide, typified by the Ti-3Al intermetalliccompound, shows potential in gas turbineengines; the gamma aluminides, representedby the Ti-Al formula, are the research materialof choice for all other applications. Variationsof both types, containing a variety of alloyingelements, are being studied to overcome theinherent low ductility and fabricability of thesecompounds.

Currently, two application areas are the focusof attention. The National Aerospace Planprovides the main impetus for developmentactivity in both airframes and hypersonicengines. The Integrated High PerformanceTurbine Engine Technology program seeks todouble the current thrust-to-weight ratio ofturbine engines. Thus, the high mach numberaerospace vehicles and propulsion systemsdesigned to usher in the age of hypersonic flightcould become a reality with these materials.

Ferro-TitaniumTitanium scrap is recycled to make ferro-titanium, which is mainly used as a steel andstainless steel additive (as a “getter” to tieup oxygen) for aerospace uses.

Other Industrial ApplicationsThese include anodes for cathodic protection(used to prevent corrosion of other metals);electro-chemical processes (such as electro-plating and anodizing); deep drilling (as ingeothermal energy exploration); hand tools;tool and machinery coatings (to enhance highspeed performance and extend life); andheating elements.

Pulp and PaperDue to the recycling of waste fluids and theneed for greater equipment reliability and lifespan, titanium has become the standardmaterial for drum washers, diffusion bleachwashers, pumps, piping systems and heatexchangers in the bleaching section of pulpand paper plants. This is particularly true forequipment developed for chlorine dioxidebleaching systems.

Flue Gas DesulphurizationLaboratory studies and field experience haveproven titanium has exceptional corrosion/erosion resistance in scrubber systems, ductingand stacks used to remove pollutants fromwaste gases. Its long life makes it a primecandidate for pollution control systems.

Food and PharmaceuticalTitanium demonstrates excellent corrosionresistance, not only to various food productsand pharmaceutical chemicals, but also tothe cleaning agents utilized. As equipmentlife becomes a more critical factor in financialevaluations, titanium equipment is replacingexisting stainless steel apparatus. Titaniumcan also eliminate the problems of metalcontamination.

Nuclear Waste StorageNuclear waste must be stored safely forhundreds of thousands of years. Titanium’sproven resistance to attack from naturallyoccurring geologic fluids, as well as itsextremely short half-life, makes it a primecandidate for multi-barrier disposal systems.

High TechnologyTitanium’s temperature and corrosionresistance and strength have created a majorrole for the metal in such applications assputter targets (for integrated circuits); super-conducting alloys (50%Nb - 50%Ti used inelectromagnets and energy storage andtransmission); shape memory alloys (springcoils in solenoids and linear motors); computers(hard drive substrates); and optical systems.

Metal Matrix CompositesTitanium is being researched as a matrixmaterial for industrial, and potentially,aerospace applications. While offering anelevated-temperature resistant, ductile base,titanium can be further strengthened with the

APPLICATIONS FOR TITANIUM

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The ULTIMATE Choice

crowns, braces, etc.). Durability and light weighthave led to its use in wheelchairs. The metal isalso widely used to fabricate surgical devicesand centrifuges.

Architecture/ConstructionAs a building material, titanium outperformsevery other architectural metal and is gainingrapid acceptance. Due to its mechanical andphysical properties, corrosion resistance andattractive appearance, it is used for exteriorcladding, roofs, fascia, canopies and dozensof other building purposes. It is also used inoutdoor art and sculptures, for its weatherresistance and striking beauty. Because itis totally immune to corrosion in all environ-ments, including marine and industrial, it isa highly practical choice when life cycle andmaintenance costs are considered. Commer-cially pure titanium, ASTM Grade 1, is mostoften specified for architectural applications.

AutomotiveWith the sheer size of the world automotivemarket, even a small amount of titanium inevery car would create a huge demand forthe metal. Because cost is a major factor inpassenger vehicles, the industry’s emphasis hasbeen on developing low cost titanium products.Designs that exploit titanium’s unique character-istics can yield parts that more than pay forthemselves with better performance and alonger life. Factors such as fuel economy,emissions legislation and longer warranties arecompelling automotive engineers to considertitanium as a “value engineering” solution.

In commercial engines, evaluations havedemonstrated that titanium valve trains canimprove fuel efficiency by 4% and they arebeing evaluated in several engines. Suspensionsprings, engine springs, exhaust systemsand brake pads are all being investigated.

Effort is also being placed in the racing market.Titanium is now used for high performancevehicle components such as valves, valvesprings, rocker arms, connecting rods andframes, due to its high strength, low weightand corrosion resistance. Titanium was usedin recent years for the fuselage skin of a testvehicle that broke the world land speed record.The automotive and motorcycle aftermarketsare also active.

Commercial and Consumer: AddingValue in Hundreds of Common UsesA combination of factors is expanding thetraditional uses for titanium to encompassa wider and wider range of applications.The titanium industry has done extensivemissionary work, costs have become morestable, availability is good and there is abetter understanding of how to work withthe metal.

Sporting GoodsOne of the first and most visible consumer usesof the metal was in titanium golf clubs. Becauseit is light and strong, club heads cast from titaniumcan be bigger, affording a larger “sweet spot” toimprove distance and accuracy. The Ti-6Al-4V

alloy dominates as a golf club materialbecause it is widely manufactured andinexpensive scrap is readily available.

The Ti-3AI-2.5V alloy has cost-effectivelydemonstrated the properties needed forother successful sports applications:good strength-to-weight ratio, lowmodulus of elasticity and excellentdampening characteristics. For these

reasons, bicycle frames and parts, tennis racquetframes, skis, pool cue shafts and baseball bats are allcurrently being fabricated from the metal. Lacrossesticks and snow shoes are also made of titanium.

Consumer GoodsTitanium’s inherent beauty and unique blendof physical properties make it a natural choice formany consumer uses, including jewelry, wrist-watches, eyeglass frames, camera bodies, andeven loudspeakers and non-stick coatings.

MedicineWith complete resistance to attack by body fluids,plus high strength and low modulus, titanium is themost biocompatible of all metals. It was first used insurgery in the 1950’s and now is widely used forhuman prosthetic and replacement devices (hipreplacements, expandable rib cages, spinal implants,etc.) Titanium will actually allow bone growth toadhere to the implants, so they last longer thanthose made of other materials. Reconstructivetitanium plates and mesh that support broken bonesare also commonly used today. Pacemaker casesand artificial heart valves are being fabricated fromtitanium, as are dental fixtures (replacement teeth,

APPLICATIONS FOR TITANIUM

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The ULTIMATE Choice

The Early Years: Prior to 1930Titanium is often perceived as a relatively new,“space age” metal, and perhaps compared tosteel, copper and aluminum, it is.

But it was 1790 when Reverend WilliamGregor, an amateur geologist, discoveredtitanium in black sand (ilmenite — FeTiO

3) on

the Cornish beaches in England. He suggestedthe new metallic substance be calledManacannite, after a nearby parish.

Five years later, an eminent German chemist,Martin Heinrich Klaproth, recognized a dioxideof the same metal in rutile ore (TiO

2) and called

the element “titanium” after the Titans, mytho-logical Greek gods of enormous strength.However, his attempts to isolate the metal failed.

In 1910 an American chemist, M. A. Hunter,finally succeeded in extracting titanium metalfrom the ore and this marked the birth of thetitanium industry. His process involved mixingTiO

2 with coke and chlorine and applying heat,

to yield titanium tetrachloride (TiCl4), which he

then reduced with sodium. The Hunter Processyielded very high purity metal which wasductile when hot, but brittle when cold; it wasmainly used as an alloying element in steel.Titanium dioxide was also a by-product ofHunter’s Process and it was recognized ashaving properties which make it an excellentwhite pigment. By 1912, TiO2 began toreplace lead oxide in paint.

Because Hunter’s Process generated such highquality titanium, it formed the basis for threecommercial sodium reduction plants thatoperatedbetween the1950’s and1992. The highpurity of HunterProcess titaniumcontributedgreatly to theacceptanceof the metal,notably in thetitanium metalpowder industry.However, theprocess proveddifficult toscale up.

THE STORY OF TITANIUM

A Historical Perspective

The Kroll Era: The 1930s - 1949In the 1930’s, Dr. Wilhelm Kroll invented the firstviable, large-scale industrial method for reducingtitanium — a production process that bears hisname. Rather than using sodium as a reducingagent, the Kroll process uses magnesium, andwhile the process can yield large amounts ofthe metal, it leaves a chloride residue and doesnot recover unreacted magnesium. The emer-gence of vacuum distillation to remove thatcontamination and improve process economicsovercame the last significant barrier to producingmass quantities of commercially pure titanium.Today, the Kroll process with vacuum distillationis the most widely used method of winning themetal from the ore.

With its exceptional strength-to-weight ratio,corrosion resistance, and temperature attributes,as well as a practical means of production,titanium attracted US Department of Defenseattention in 1946 as the best answer to designproblems in high performance aircraft. Themodern-day titanium industry was truly launchedin the late 1940’s, when it was first used in flight— on the Douglas Aircraft X3 Stilletto.

The Aerospace Years: 1950 - 1980For many years titanium remained almostexclusively a jet engine and airframe material.Each new aircraft used a greater percentageof titanium and by 1957, U.S. mill productshipments reached 12 million pounds, 96%of which was devoted to aerospace use.

During the 1960’s, commercial airline fleet buildupand corresponding technical advances in titaniumproduction, alloys and quality caused use of themetal to surge. Throughout the next two

decades, despitethe aerospaceindustry’s histori-cally cyclicalnature, the overalltrend was a risein the use of themetal in aerospaceapplications. In1960, U.S. millproduct shipmentswere 10 millionpounds; by 1970,that figure tripled,to 30 millionpounds, and in1980 it was over50 million pounds.

Approximate U.S. Titanium Mill Products Shipments

Year

Source: ITA

Mill

ion

Po

un

ds

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The Diversification Years: 1970 - 1995Since the late 1950’s, it was recognized thattitanium’s natural corrosion resistance made ita strong candidate for industrial uses. In 1959,titanium tubing was installed in power plantheat exchangers cooled with seawater and, overthe next several years, it showed absolutely nosigns of pitting or corrosion.

Building on thatsuccess, titaniummanufacturersactively pursuedindustrial applica-tions. In 1971, thefirst power plant touse titanium tubedsurface condenserswent on-line and,by 1975, this wasthe fastest growingindustrial applica-tion for titanium.

Titanium producershave also success-fully introducedthe metal and itsalloys into a varietyof industrial andother uses. The chemical processingindustry uses it for heat exchangers,process flow equipment and vessels,primarily for its corrosion resistance andresultant low life cycle cost. For the oiland gas industry, it is crucial in offshoreexploration and production and subsequenthydrocarbon processing. It is used in consumerproducts from eyeglass frames to jewelry; asan architectural and racing car material and incommon recreational products from golf clubsto bicycles. Titanium improves the quality ofindividual lives when it is used for medicalimplants, prosthetic devices, eyeglasses andeven lightweight wheelchairs.

By 1997 U.S. mill product shipments were over60 million pounds, of which 40% was used inapplications other than aerospace.

The PresentThe reasons for titanium’s growth over the past40 years — in both aerospace and industrial/commercial applications — are numerous.

Of course, the metal remains a staple of theaircraft industry. With each new design,aircraft manufacturers make planes larger and

also increase the amount of titaniumused in each plane. Titanium usageon Boeing aircraft has increased from2% empty weight on the 737 to 8%on the 777.

Abundant raw material supply andinvestments to improve manufacturingtechnology and increase capacity haveincreased the metal’s availabilityand lowered its cost. Research anddevelopment have yielded an ever-broadening range of alloys and

product forms suited to specific needs.Educational efforts have promoted the easeof common fabrication techniques, suchas machining, forging and Tungsten InertGas welding.

With these developments, the titaniumindustry foresees promise for the metal’sexpanded role in automotive uses, sour andoffshore hydrocarbon production, chemical andpetrochemical processing, marine applications,water desalination and architecture.

THE STORY OF TITANIUM

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The ULTIMATE Choice

Extracting titanium from the oreTitanium is the fourth most abundant metallicelement in the earth’s crust. In its elementalform it occurs primarily as ilmenite (titanium-iron oxide — TiFeO3) and rutile (titaniumdioxide — TiO2). Although these compoundsare found on all seven continents, Australia isby far the largest supplier of both. Commonblack beach sand is rich in rutile, which hasthe highest titanium content of any sourcematerial. About 95% of all titanium mined isused to manufacture TiO2, an important pigmentthat adds whiteness, brightness and opacity topaint, plastic, paper and ink. The other 5%is used to manufacture metal.

To produce pure titanium, the ore — usuallyrutile — is converted to titanium metal“sponge” (so-called for its ocean-sponge-likeappearance) in two distinct steps. First theTiO2 is mixed with coke or tar and chargedin a chlorinator, where chlorine gas is passedthrough the heated, fluidized bed charge. Thetitanium ore reacts with the chlorine to formtitanium tetrachloride (TiCl4), a colorless liquid,and the oxygen is removed as CO and CO2.

The TiCl4 is then reacted in the Kroll process,which uses magnesium as a reducing agentunder an inert atmosphere. The resultantmetallic sponge is then either leached, inert-gasswept or vacuum distilled to remove the excessmagnesium chloride and unreacted magnesiummetal, which are recycled. Vacuum distillationresults in lower levels of magnesium, hydrogenand chloride. The pure titanium sponge mustmeet stringent specifications to assure controlof the ingot’s composition.

Melting to Ingot: Vacuum ArcRemelting and Cold Hearth MeltingMelting is the next step. This takes placein either a vacuum arc remelt furnace,to produce VAR ingots typically used foraerospace applications, or in an cold hearth(electron beam or plasma arc) furnace, tofulfill industrial requirements, or to producefeedstock for a subsequent VAR melt.

From Black Sand to a Range of Mill Products

PRODUCING TITANIUM

For vacuum arc remelting, the titanium sponge iscrushed and blended with the desired alloyingelements, such as aluminum, vanadium, molyb-denum, tin and zirconium. (The percentageof each alloying element in the final metal isexpressed as a number in front of its atomicsymbol. For example, Ti-6Al-4V consists of 90%titanium, 6% aluminum and 4% vanadium.)The composition is then pressed into briquetswhich are welded together to form anelectrode. In the VAR furnace, the electrodeis “consumable melted” by an arc struckbetween it and a layer of titanium in a water-cooled copper crucible. The molten titaniumon the outer surface solidifies on contact withthe cold wall, forming a shell or skull to containthe molten pool. The ingot is not poured, butsolidifies under vacuum in the melting furnace.A second melt insures homogeneity of theingot for industrial purposes; a triple meltingoperation is used for all metal destined foraerospace use. The resultant VAR ingots arecylindrical shapes weighing up to 30,000pounds, which are forged to slabs or billets,then formed to mill products.

The alternative sponge melting process usesa cold hearth furnace. Here, the crushedsponge and alloying elements can also bemixed with inexpensive recycled titanium scrapbefore melting, to reduce costs. The mixture ismelted by either electron beams in a vacuum orby plasma arc torches under a positive pressureof helium. The metal flows across the coldhearth, where it forms a pool that allowsimpurities to sink to the bottom or to beevaporated. Cold hearth melting removesboth hard alpha and high density inclusionsand is the preferred method for producingclean titanium for aerospace applications.Because it can use a high percentage of scrap,cold hearth melting is also used to produceaffordable titanium for industrial and commercialuses. The molten titanium is direct cast into anear net shape, which can be a slab intendedfor further processing, or a remelt electrodewhich can then be VAR melted to meetaerospace requirements. Combination coldhearth/VAR melts can eliminate inclusionsand defects that even triple VAR meltingcannot remove.

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The ULTIMATE Choice

PRODUCING TITANIUM

Typical Production Flow Chart for Titanium Sponge, Mill Products and Castings

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The ULTIMATE Choice

ExtrusionsTitanium is cost-effectively extruded intodesired near-net shapes by forcing heatedmetal through a die. Extrusions maximizematerial usage and reduce the need fordownstream milling, welding or assembly.

Fastener Stock and WireThis is limited to rounds with diameter lessthan or equal to ½”.

Other Common Product FormsThese include weld wire, fasteners, screws,nuts, bolts, washers and rod.

Casting: Efficient Production ofNear Net ShapesCasting is the most advanced and diversifiedof the net shape technologies. It offers greaterdesign freedom and significantly reduces theneed for expensive machining or fabricationto attain the desired shape. Commercialcasting began in the late 1960’s and todaythe technology has matured to routinely supplycritical gas turbine engine, air frame, chemicalprocess and marine products.

Both precision investment casting as well asrammed graphite (sand) molding systems areemployed. The economy of investment castingoften favors it as an alternative to fabrications,hog-outs and sheet metal build up assemblies.Investment casting can be used to create large,tolerance-critical parts such as heat shields, fanframes and missile components, as well assmaller parts such as valve bodies. The samepattern equipment used to produce steel partsis often used to produce titanium chemicalpump and valve components, while aerospaceparts normally require their own tooling.

Mechanical properties of titanium castings aregenerally comparable to their wrought counter-parts. Toughness and crack growth resistanceare generally superior, strength is almost thesame, while high cycle fatigue is normally alittle lower. Hot isostatic pressing (HIPPING) isused to eliminate internal porosity in castings,in order to improve fatigue life.

Powder Metallurgy: A Promise ofLower Cost and Wider UsesTitanium powder technology may offer lowercosts in the manufacture of near-net shapesand, with the potential of lower cost powdervia plasma quenching production, it couldopen a wider range of applications.

PRODUCING TITANIUM

316

316

Diverse Mill Products ForMultiple UsesVAR ingots and cold-hearth melted, cast slabs arepressed or rotary forged into slabs (rectangularshapes) or billets (rough round bar or variousother shapes). Then, hot forming producesforgings, rollings and extrusions. This can befollowed by cold rolling and common processingtechniques to create mill products — basicstructural shapes with desired properties thatmaximum metal utilization. The majority ofaircraft and some industrial components requirehot working to overcome springback, minimizestresses and reduce the high forming forcesneeded for titanium alloys. Superplastic formingand diffusion bonding under pressure andtemperature have recently found acceptance.All mill products are available in the spectrumof alloys and grades.

ForgingsThe workhorse of the aerospace industry anda feedstock for additional mill products, forgingsare available in a wide range of sizes. Newdevelopments in precision forging now providenear-net shapes with improved material efficiencies.

BilletBillet can have round, square, rectangular,hexagonal or octagonal shapes. Cross-sectionalarea is equal to or greater than 16 square inchesand width is less than five times thickness.

Rod and BarRounds have diameters greater than ½” andless than or equal to 4½”. Squares have crosssections less than 16 square inches. Rectangleshave cross-sections less than 16 square inches,thicknesses greater than ” and widths lessthan or equal to 10 inches.

PlateHot-rolling produces plate, which is generallyavailable in thicknesses greater than ” andwidth greater than 20”. Vacuum creep flatteningis widely used to achieve critical plate flatness.

Sheet and StripSheet is flat-roll product that is typically lessthan ” thick, and produced by either hot orcold rolling. Strip is cut from cold-rolled andannealed sheet.

Pipe and TubePipe and tube can be manufactured as eitherwelded or seamless product in a variety ofstandard diameters and wall thicknesses.Titanium pipe, fittings and flanges are normallyavailable in standard schedules and sizes.

316

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The ULTIMATE Choice

FABRICATING TITANIUM

Conventional Techniques From the Straightforward to the Sophisticated

MachiningWhile titanium presents a unique set ofmachining circumstances, all of the customarymethods can be used and it is no more difficultto machine than Type 316 stainless steel,depending on alloy grade. Titanium’s tendencyto gall and its low modulus can be counter-acted by using consistently sharp tools; heavy,non-stop feeds; rigid set-ups; slow speeds andan abundance of soluble coolant. Workhardening rate is less than that for stainlesssteels. Drilling and cold saw cutting requiresharp, clean tools with good chip removal andample coolant. Grinding also requires effectiveuse of coolant as well as proper wheel andwheel speed selection.

CuttingTorchcutting with oxyacetylene flame can beaccomplished on titanium sections up to 6”thick. Waterjet and laser cutting are widelypracticed.

CladdingA range of processes is available for cladding,primarily for industrial equipment applications.Explosive bonding and mechanical fastenedloose lining have been used for years. Morerecently roll cladding, resistance weld liningand diffusion bonding are being used.

Conventional metal processing tools andprocedures can be used to form, machineand join titanium and its workability iscomparable to that of ¾ hard stainless steel.The technology of fabricating titanium hasalso evolved to offer a wide range of highlysophisticated techniques. End applicationspecifications and economics should deter-mine which processes are used.

Although titanium is readily fabricable,some distinct differences from otherstructural metals should be recognized:lower modulus of elasticity, higher meltingpoint, lower ductility, propensity to galland sensitivity to contamination in air attemperatures above 800oF (425oC). Also,consideration must be given to the gradeor alloy, heat treatment and metallurgicalcondition.

FormingTitanium can usually be cold worked onequipment designed for stainless steel ornickel-based alloys. Although it can bereadily bent, sheared, pressed, deep-drawnand so on, it is necessary to take into accounttitanium’s strong springback characteristics.Press brakes (used for forming sheet andplate), shears, cold rolls, hydro-press forming,drawing and pilgering equipment can allbe used.

WeldingWelding titanium and its alloys is readilyperformed in the field, without a vacuum,but it is necessary to eliminate reactive gases(including oxygen, nitrogen and air) and tomaintain cleanliness. Welding by meansof the Tungsten Inert Gas process (TIG) usingargon gas shielding is the most common.Plasma, laser, resistance, electron beam,Metal Inert Gas (MIG), and friction weldingare widely practiced.

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The ULTIMATE Choice

Pure titanium exists in two crystallographicforms. The first is alpha, which has a hexagonalclose-packed crystal structure that is stable upto 1620oF (880oC). At that point, it transformsto a body-centered cubic structure, the betaphase, which is stable to the melting point.

As alloying elements are added to puretitanium, they tend to change the temperatureat which the phase transformation occursand the amount of each phase present. Alloyadditions tend to stabilize either the alphaphase to higher temperatures or the betaphase to lower temperatures. The mostimportant alpha stabilizers are aluminumand oxygen; the key beta stabilizers includemolybdenum, vanadium, chromium and iron.

There are four basic classes of titanium-basedmaterials, each favoring selected, specificcharacteristics. The family of titanium alloysoffers a full range of strength properties fromthe highly-formable, lower strength to the veryhigh-strength. Most of the alpha-beta andbeta alloys can provide a myriad of strength-ductility property combinations throughadjustments in alloy heat treatment and/orcomposition. With the wide selection oftitanium alloys available, optimum choice fora given environment is almost always possible.

Commercially Pure (Unalloyed)TitaniumCP titanium is less expensive, generally morecorrosion resistant and lower in strength thanits alloys, and is not heat-treatable. It is highlyweldable and formable, and used primarily inapplications requiring corrosion resistance andhigh ductility, where strength is not a primeconsideration. Grade 1 is the purest, usedin many chemical and marine applications;Grade 2 is considered an industrial ‘workhorse;’Grade 3 has higher strength than Grade 2 andis often used in the same applications; Grade 4 isoften used in marine applications. There arealso grades with a small palladium contentthat increases resistance to crevice corrosionat high temperatures and low pH.

THE METALLURGY OF TITANIUM

The Alpha and Beta Forms of Titanium and Its Alloys

Alpha and Near-Alpha AlloysThe alpha alloys are non-heat treatable andare generally very weldable. They have lowto medium strength, good notch toughness,reasonably good ductility and possess excel-lent mechanical properties at cryogenictemperatures. The more highly alloyed alphaand near-alpha alloys offer optimum hightemperature creep strength and oxidationresistance as well. All-alpha alloys are usedin forgings such as gas turbine engine casingsand rings. Near-alpha alloys are used forairframe skin and structural components,seamless tubing and moderately hightemperature applications such as jetengine compressor blades.

Alpha-Beta AlloysMost of the alloys now in use fall into thealpha-beta phase, including Ti-6Al-4V whichcomes as close as possible to being a generalpurpose titanium alloy. These alloys areheat treatable and most are weldable. Theirstrength levels are medium to high. Their hotforming qualities are good, but the hightemperature creep strength is not as goodas most alpha alloys. Alpha-beta alloys arecapable of excellent combinations of strength,toughness and corrosion resistance. Typicalapplications include blades and discs for jetengine turbines and compressors, structuralaircraft components and landing gear,chemical process equipment, marinecomponents and surgical implants.

Beta and Near-Beta AlloysThe beta alloys are readily heat treatableto high strengths, generally weldable, andhave good creep resistance to intermediatetemperatures. Excellent formability can beexpected in the solution treated condition.Beta-type alloys also have good combinationsof properties in sheet and heavy sections.Typical applications include high strengthairframe components, fasteners, springs,pipe and commercial and consumer products.

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The ULTIMATE Choice

TITANIUM METAL TERMINOLOGY

Reduction - - - - - The process of converting TiCl4 to titaniummetal using a reducing agent such as magnesium or sodium.

Magnesium Reduction - - - - - Titanium tetrachloride combinedwith molten magnesium metal in a steel reactor under acontrolled atmosphere yields titanium metal in sponge formand magnesium chloride (MgCl

2) as a by product. The pores

in the spongy mass of titanium are filled with Mg or MgCl2.

This residual material is removed either by leaching orvacuum distillation.

Vacuum Distillation - - - - - For the vacuum distillation process,366 stainless steel reactor pots are used. After the reductionis completed, the hot reactor pot is transferred to a cold wallvacuum furnace and the residual Mg-MgCl

2 is distilled over

into a collection vessel for recovery.

Electrolytic Cell - - - - - Magnesium chloride (MgCl2) is electrolyzedto recapture chlorine gas and magnesium metal, both ofwhich are recycled through the process.

Sponge - - - - - A porous metal product of the chemical reductionof titanium tetrachloride to metal by the Kroll or Hunter process.

Kroll Process - - - - - A process for the production of titaniumsponge metal where the reducing agent is magnesium.

Hunter Process - - - - - The Hunter Process uses sodium as thereducing agent. The sponge produced is purified by a weakacid leach. Between 1990 and 1994 all of the companiesusing the Hunter Process have gone out of business orshutdown that section of the plant.

Leaching - - - - - Titanium sponge passes through a rotary-leachingvessel (made from titanium) where aqua regia and waterremove trace magnesium and other impurities.

Leached Sponge - - - - - A sponge metal that has been purifiedby using a weak acid to remove the impurities, such asunreacted reducing agent or by-product salt from the sponge.

Distilled Sponge - - - - - A sponge metal that has been purified byvacuum distillation instead of leaching. The impurities areremoved from the pores of the sponge by vaporizing ratherthan digestion in leaching.

Sponge Mass - - - - - Is the 18,000-pound cylindrical block ofsponge pushed out of the reactor vessel after the completionof reduction and distillation.

Titanium Crystals - - - - - A high purity titanium crystal produced bythe iodide of electro-refining process. Normally in the 55 to 90Bhn range.

Coke - - - - - The carbon feed material used in chlorination.

Sodium - - - - - The agent used to reduce TiCl4 to titanium metal inthe Hunter Process.

HEAT TREATING

Heat Treating - - - - - Is the process of altering the properties of ametal by subjecting it to a controlled sequence of thermalcycles. The time of retention at a specific temperature andthe rate of cooling are as important as the temperature itself.Heat treatment can be performed to improve machinability,increase toughness, improve cold forming characteristics,alter hardness ad tensile strength, up and down, and torelieve residual stress as well as improve shearability.

Annealing - - - - - Refers to a variety of operations involvingheating and slow cooling to remove stresses and alter ductilityand toughness. Annealing softens the titanium making itmore workable for shearing, forming and machining.

Stress Relieving - - - - - Removes residual stresses from withinthe metal.

Quenching - - - - - Rapid cooling from a specific temperature.

Turning, Grinding and Polishing - - - - - Produces bars that arecharacterized by superior surface finish, dimensional precisionand straightness.

ROUGH PRODUCT SHAPES

vIngots - - - - - Cylindrical in shape with a 1.5 or more length todiameter ratio. A typical production ingot in 34” diameterby 96” long and weighs 14,000 pounds.

Bloom – – – – – Semi-finished billet, slab or bar of titanium thathas been hammered, forged or rolled from an ingot.

Billet - - - - - Piece of semi-finished titanium square or nearlysquare in section, made by rolling an ingot or bloom.

Slab – – – – – Semi-finished titanium block having a rectangularcross-section in which the width is at least twice the thick-ness. Slab is also a cast product from EB or plasma melting.

TITANIUM SPONGE PRODUCTION

Titanium Ore - - - - - The most common ore used in the titaniummetals industry is rutile which is a black beach sand containing+95% TiO

2. The alternate ore is ilmenite, which is only

55 to 60% TiO2 with the remainder being iron oxides.

Chlorination - - - - - Rutile ore (TiO2) reacts with chlorine gas atelevated temperatures to yield titanium tetrachloride, acolorless liquid.

Chlorination - Titanium Tetrachloride, TicCl4, Tickle - - - - -Titanium Tetrachloride is the product of chlorinating titaniumdioxide “with Cl in the presence” of carbon to remove theoxygen and produce TiCl

4. As used in the metals industry, it

is a clear, colorless liquid at room temperature.

Titanium Dioxide - - - - - TiO2 is a pure white material used aspigment in paint. Over 90% of all titanium ores that aremined end up as pigment. TiO

2 is also used in cosmetics

such as lipstick.

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The ULTIMATE Choice

The International Titanium Association accepts no responsibility for either the accuracy or completeness of the information containedherein and, by publishing the same, should not be perceived as making any industry recommendation. Additional information may beavailable which may have a material effect on the interpretation and use of the information provided.

Copyright © International Titanium Association, 1987, 1990. Revised 1999. ISBN 0-935297-07-3

E0301 10/99

The International Titanium Association gratefully acknowledges the contributions of source material,knowledge and expertise from the following individuals, organizations, corporations and publications.

Stanley Abkowitz, Dynamet Technology, Inc.

Dr. Paul Bania, Ti-PRO

Larry Blivas, Airport Metals, A Member of the Samuel Group

Dr. Joseph S. Broz, TIMET

Craig Carlson, TIMET

Al Donlevy, Dynamet Incorporated

Economics of Titanium Metal, The. First Edition. Roskill Information Services Ltd. 1998.

John Fanning, TIMET

Steve R. Giangiordano, RMI Titanium Company

Jim Grauman, TIMET

International Titanium Applications Conferences, 1994 & 1996. Technical Programs Proceedings.International Titanium Association.

Wendy Z. McGowan, VALTIMET

Metals Red Book, The, Volume 2, published by Casti Publishing, Inc.

Robert J. Marsh, Jr., OREMET -Wah Chang, An Allegheny Teledyne Co.

Michael Metz, TIMET

John Monsees, Hi-Tech Welding Services Incorporated

John Mountford, TIMET

Newsletters of the Titanium Development Association and International Titanium Association, various contributors.

Pete Philippon, Titanium Industries Incorporated

Eldon Poulsen

Shedding New Light on Titanium in CPI Construction, James S. Grauman & Brent Willey, Chemical Engineering,August 1998.

Ronald Schutz, RMI Titanium Company

Chris Sommer, Ti-PRO

TIMET (Titanium Metals Corporation) Website: timet.com

Titanium. The Japan Titanium Society

Titanium, A Technical Guide. Edited by Matthew J. Donachie, Jr., ASM International, 1988.

Titanium Industries, Inc. Website: titanium.com

Twenty Five Years of Titanium News. Suisman Titanium Corporation, November, 1995.

AUTHORING/EDITING ACKNOWLEDGEMENTS

20

INTERNATIONAL TITANIUM ASSOCIATION1871 Folsom Street, Suite 200

Boulder, Colorado 80302-5714 USA

(303) 443-7515 Phone

(303) 443-4406 Fax

www.titanium.org