1_ht_ferrous and non-ferrous metals

Ferrous and Non-Ferrous Metals

Advanced Training Institute (ATI)

Chennai

Yuvaraj Chinnaiyan

Ferrous Metals And Non-Ferrous Metals

• One method of classifying metals is by their content, and one common

division is into ferrous metals and non-ferrous metals. The term ferrous is

derived from the Latin "Ferrum" which means "containing iron", thus ferrous

metals contain iron and non ferrous metals do not. Ferrous metals may be

pure iron, like wrought iron, or they may be alloys of iron and other

elements. Steel, being an alloy of iron and carbon, would therefore be a

ferrous metal.

26th element Iron or Ferrous 55.85 Atomic Mass

Ferrous Metals And Non-Ferrous Metals

• Ferrous metals are often magnetic, but this property is not in and of itself

sufficient to classify a metal as ferrous or non-ferrous. Austenitic stainless

steel, a ferrous metal, is non-magnetic, while cobalt is magnetic but non-

ferrous. Ferrous metals are usually magentic, but there are a still some non-

ferrous metals that are magnetic as well.

Ferrous Metals And Non-Ferrous Metals

• Common ferrous metals include the various irons and steels. Common non-

ferrous metals include aluminium, tin, copper, zinc, and brass, an alloy of

copper and zinc. Some precious metals such as silver, gold, and platinum

are also non-ferrous.

• Summary: Non-ferrous metals mean they do not contain iron and ferrous

metals mean they do contain iron. Ferrous metals are usually magnetic,

although SOME non-ferrous metals are also magnetic.

Production of Iron and Steel

Raw Materials for Production

• Iron Ore

• Limestone ----------

• Coke

Iron Ore

• Abundant, makes up 5% of earth’s crust• Is not found in ‘free state’, must be found in rocks

and oxides, hence Iron ore.• After mining, the ore is crushed and the iron is

separated, then made into pellets, balls or briquettes using binders, such as water.

• The pellets are typically 65% iron, and about 1” in diameter.

Coke – (…The black, legal kind)

• Coke is formed by heating coal to 2100*F (1150 C), then cooling it in quenching towers.

You need more than Iron? Why coke is used…1. Generates high heat, needed in order for chemical reactions in ironmaking to take place.

2. Produces CO (carbon monoxide) which reduces

iron-oxide to Iron.

Lastly, Limestone

• Limestone (calcium carbonate) is used to remove impurities.

– When the metal is melted, limestone combines with impurities and floats to the top of the metal, forming slag. The slag can then be removed, purifying the iron.

Ironmaking

Raw Materials Pig Iron

• The three raw materials are dumped into a blast furnace.

• Hot air (2000*F) is blasted into the furnace, which helps drive the chemical reaction. The coke forms CO and the CO reduces the iron oxide to iron.

• The slag floats to the top and the metal is transferred to molds and cools. IT IS NOW PIG IRON, ready for more iron work or steelmaking.

Blast Furnace

Tuyeres

(Same height as a 10 story building)

Steelmaking

Pig Iron Steel

• To make steel you are simply removing more impurities, such as, manganese, silicon, carbon…, from the pig iron.

• Impurities are removed by re-melting the metal and adding carbon, steel scrap, and more limestone.

– The metal can be melted using one of three methods.– Open-Hearth furnace– Electric furnace– Basic Oxygen furnace. (BOF)

Open-Hearth Furnace

Uses a fuel to generate heat, and melt the metal.

Basic-Oxygen Furnace• Fastest steelmaking process – can

make 250 tons of steel / hour• Melted pig iron and scrap are poured

(charged) into a vessel.• Fluxing agents are added, like

limestone.• The molten metal is blasted with pure

oxygen. This produces iron oxide which then reacts with carbon to produce CO and CO2. The slag floats to the top of the metal.

• Higher steel quality than open hearth. Used to make plate, sheet, I-beam, tubing and channel.

Electric Furnace

• Uses electric arc from electrode to metal to heat and melt it.• Can produce 60-90 tons of steel per day.• Steel is higher quality than open-hearth and BOF

Vacuum Furnace

• Uses induction furnaces.• Air is removed from the furnace, this removes the

gaseous impurities from the molten metal. • Produces very high-quality steel.

Casting Ingots

Ingots

• While steel is still molten, it is poured into a mold. The mold may be a square, rectangle or round. The metal becomes an “ingot” in the mold.

• They can weigh 100 lbs to 40 tons.

• The ingot will be removed from the mold and heated uniformly to be rolled or formed into a final product.

• HOWEVER – While the molten metal cools, or solidifies, gasses evolve and can affect the quality of the steel. This leads to three types of steel: Killed Steel, Semi-Killed Steel, and Rimmed Steel.

Killed – Semi-Killed – Rimmed Steel

• Killed Steel – This is a fully deoxidized steel, and thus, has no porosity.

– This is accomplished by using elements like aluminum to de-oxidize the metal. The impurities rise and mix with the slag.

– It is called killed because when the metal is poured it has no bubbles, it is quiet.

– Because it is so solid, not porous, the ingot shrinks considerably when it cools, and a “pipe” or “shrinkage cavity” forms. This must be cut off and scrapped.

Killed – Semi-Killed – Rimmed Steel

• Semi-Killed Steel: This is practically the same as killed steel, with some minor differences.

– It is only partially de-oxidized, and therefore, is a little more porous than killed steel.

– Semi-Killed does not shrink as much as it cools, so the pipe is much smaller and scrap is reduced.

– It is much more economical and efficient to produce.

Killed – Semi-Killed – Rimmed Steel

• Rimmed Steel: This is produced by adding elements like aluminum to the molten metal to remove unwanted gases. The gasses then form blowholes around the rim.

– Results in little or no piping.

– HOWEVER, impurities also tend to collect in the center of the ingot, so products or rimmed steel need to be inspected and tested.

**Refining

Continuous Casting

-Molten metal skips ingot step, and goes directly the furnace to a “tundish”

-Metal solidifies in the mold-The metal descends @ about 1”/sec-The solidified metal then goes through ‘pinch rollers’ that determine the final form.

Benefits of Continuous Casting

• Costs less to produce final product

• Metal has more uniform composition and properties than ingot

processing.

Residual Elements• During the processing of

steels some residual elements remain in the metal.

• These residuals are trace elements that are unwanted due to their detrimental properties but cannot be extracted completely.

• Some of these residual elements include: antimony, arsenic, hydrogen, nitrogen, oxygen, and tin.

Molten Steel

Ferrous Metals

• Mild Steel » Composition -0.15 to0.30% carbon » Properties- Tough, high tensile strength, ductile.

Because of low carbon content it can not be hardened and tempered. It must be case hardened.

» Uses- girders, Plates, nuts and bolts, general purpose.

Ferrous Metals

• High Speed Steel » Composition- medium carbon, tungsten, chromium

and vanadium. » Properties - Can be hardened and tempered. Can be

brittle. Retains hardness at high temperatures.» Uses- Cutting tools for lathes.

Ferrous Metals

• Stainless Steel » Composition- 18% chromium, and 8% nickel added. » Properties - Corrosion resistant » Uses- Kitchen draining boards. Pipes, cutlery,

aircraft.

Stainless Steels

• The reason for the name stainless is due to the fact that in the presence of oxygen, the steel develops a thin, hard, adherent film of chromium. – Even if the surface is scratched, the protective film is

rebuilt through passivation.• For passivation to occur there needs to be a minimum

chromium content of 10% to 12% by weight.

Stainless Steels

• Stainless steels tend to have lower carbon content since increased carbon content lowers the corrosion resistance of stainless steels.

– Since the carbon reacts with chromium it decreases the available chromium content which is needed for developing the protective film.

Stainless Steels• Using stainless steels as reinforcing bars, has become

a new trend, in concrete structures such as highways buildings and bridges. – It is more beneficial than carbon steels because it is

resistant to corrosion from road salts and the concrete itself.

Rebar corrosion in concrete

Ferrous Metals

• High Tensile Steel » Composition- Low carbon steel, nickel, and

chromium. » Properties- Very strong and very tough. » Uses- Gears, shafts, engine parts.

Ferrous Metals

• High Carbon Steel» Composition- 0.70% to 1.40% carbon. » Properties- The hardest of the carbon steels. Less

ductile, tough and malleable. » Uses- Chisels, hammers, drills, files, lathe tools, taps

and dies

Ferrous Metals

• Medium Carbon Steels» Composition- 0.30% to 0.70% carbon.» Properties- Stronger and harder than mild steels.

Less ductile, tough and malleable. » Uses- Metal ropes, wire, garden tools, springs.

Tool and Die Steels

• Tool and die steels are alloyed steels design for high strength, impact toughness, and wear resistance at normal and elevated temperatures.

– High-speed steels Maintain their hardness and strength at elevated operating temperatures. There are two basic types the M-series and T-series

Tool and Die Steels

• M-series contain 10 % molybdenum and have higher abrasion resistance than T- series

• T- Series contain 12 % to 18 % tungsten. They undergo less distortion in heat treatment and are less expensive than the M-series.

M- series steel drill bits coated with titanium

Tool and Die Steels

• Dies are tools used for drawing wire, and for blanking, bending, cutting, machine forging, and embossing. .– H-series (Hot-working steels) for use at

elevated temperatures. They have high toughness and high resistance to wear and cracking.

– S-series (shock resisting steels) designed for impact toughness.

Ferrous Metals

• Cast Iron » Composition- Remelted pig iron with small amounts

of scrap steel. » Properties- Hard, brittle, strong, cheap, self-

lubricating. » White cast iron, grey cast iron, malleable cast iron. » Uses- Heavy crushing machinery. Car cylinder

blocks, vices, machine tool parts, brake drums, machine handle and gear wheels, plumbing fitments

Alloy Steels

• High-strength, low-alloy steels (HSLA) steels were developed to improve the ratio of strength to weight. – Commonly used in

automobile bodies and in the transportation industry (the reduced weight makes for better fuel economy ).

• Microalloyed steels

Provide superior properties without the use of heat treating. When cooled carefully these steels develop enhanced and consistent strength.

Alloy Steels

• Nanoalloyed steels have extremely small grain size (10-100 nm). Since their synthesis is done at an atomic level their properties can be controlled specifically.

Steel Products

Steel Products

• Rolled Structural Shapes

Steel Products

• Sheet Piling» Sections are made to interlock abd are available in

several shape.

Steel Products

• Steel Pipe» Seamless or welded small diameter pipe and

electrically welded large diameter pipe.» A large diameter pipe is made by having plates with

proper width, beveled edges and placed in a press which forms them into cylinders. The two edges are welded together and the pipe is brought to its final diameter by hydraulically expanding the welded sheet against a retaining jacket.

Steel Products

• Reinforcing Steel» Made from new steel or from discarded railway – car

axles or rails.» Reinforcing steel comes in plain or deformed bars,

that is, bars which have lugs or deformation rolled on the surface to provide anchorage in concrete.

Steel Products

• Welded Wire Fabric» Another type of reinforcing material. It consists of

parallel, longitudinal wired welded to transverse wires at regular intervals.

Steel Products

• Steel Wire» Over 150,000 uses for wire including pins, needles,

nails, bolts, cables, piano wire, fences.

Steel Products

• Bolts and Nuts» (either hot forged or cold-formed from wire of the

appropriate diameter). For bolts, wire is fed into an automatic bolt-making machine which cuts to length heads, trims, points, and, in many cases rolls the thread.

Steel Products

• Steel Strapping» Made from high-tensile flat wire in a number of sizes.

Used for banding forms to keep them from bulging under the pressure if freshly poured concrete. A tightener tightens it and the two lapped end is sealed.

Steel Products

• Open Web Steel Jolt» Lightweight warren-type trusses made in several

different styles.

Steel Products

• Sheet Steel» Black and galvanized, can be used to manufacture

corrugated roofing and sliding and formed steel decking. Corrugated sheets have one edge turned up, one turned down.

Steel Products

• Sheet Steel» Two basic styles are open-faced decking and cellular

decking which allow easy distribution of electric systems and outlets.

Steel Products

• Steel Studs» Lightweight, requiring minimum storage space and

does not wrap or shrink. Fasteners do not pop, and joints stay closed. Much faster to install to than wood-stud installation. Available in 1 1/8, 2 ½ and 3 5/8 inches.

» Plumbing stacks and electrical components fit easily into a steel-frame wall.

Steel Products

• Pans and Domes» Manufactured for use in forming one-way and two-

way ribbed concrete floor systems.

• Aluminum » Composition- Pure Metal » Properties- Grayish-White, soft, malleable,

conductive to heat and electricity, It is corrosion resistant. It can be welded but this is difficult. Needs special processes

» Uses- Aircraft, boats, window frames, saucepans, packaging and insulation, pistons and cranks

Non-Ferrous Metals

Non-Ferrous Metals

• Aluminum alloys » Composition- Aluminum +4%

Copper+1%Manganese » Properties- Ductile, Malleable, Work Hardens » Uses- Aircraft and vehicle parts

Non-Ferrous Metals

• Copper » Composition- Pure metal Copper+1%Manganese » Properties- Red, tough, ductile, High electrical

conductor, corrosion resistant, Can work hard or cold. Needs frequent annealing

» Uses- Electrical wire, cables and conductors, water and central heating pipes and cylinders. Printed circuit boards, roofs

Non-Ferrous Metals

• Brass » Composition- 65% copper +35%zinc » Properties- Very corrosive, yellow in colour,

tarnishes very easily. Harder than copper. Good electrical conductor

» Uses- Castings, ornaments, valves, forgings

Non-Ferrous Metals

• Lead » Composition- Pure metal » Properties- The heaviest common metal. Soft,

malleable, bright and shiny when new but quickly oxidizes to a dull grey. Resistant to corrosion.

» Uses- Protection against X-Ray machines. Paints, roof coverings, flashings

Non-Ferrous Metals

• Zinc » Composition- Pure metal » Properties- A layer of oxide protects it from

corrosion, bluish-white, easily worked » Uses- Makes brass. Coating for steel galvanized

corrugated iron roofing, tanks, buckets, rust-proof paints

Non-Ferrous Metals

• Tin » Composition- Pure metal » Properties- White and soft, corrosion resistant » Uses- Tinplate, making bronze

Non-Ferrous Metals

• Gilding metal » Composition- 85% copper+15% zinc » Properties- Corrosion resistant, golden colour,

enamels well » Uses- Beaten metalwork, jewelry

Carbon and Alloying Steels

• Carbon and alloying steels are the most commonly used metals

• The structural makeup and controlled processing of these steels make them suitable for many different functions.

• Basic product shapes include plate, sheet, bar, wire, tube, castings, and forgings.

• Increasing the percentages of these elements in steels, increases the properties they impart.

Effects of Elements in Steels

• Different elements are added to steels to given the steel different properties.

• The elements pass on properties such as harden- ability, strength, hardness, toughness, wear resistance, etc.

• Some properties are beneficial while others are detrimental.

Effects of Elements in Steels• Boron: Improves hardenability without the loss of (or even

with some improvement in) machinability and formability. • Calcium: Deoxidizes steels, improves toughness, and may

improve formability and machinability. • Carbon: improves hardenability, strength, hardness, and wear

resistance; it reduces ductility, weldability, and toughness.• Cerium: controls the shape of inclusions and improves

toughness in high-strength low alloy steels; it deoxidizes steels.

• Chromium: improves toughness, hardenability, wear and corrosion resistance, and high-temperature strength; it increases the depth of the hardness penetration resulting from heat treatment by promoting carburization.

• Cobalt: improves strength and hardness at elevated temperatures.

Effects of Elements in Steels

• Copper: improves resistance to atmospheric corrosion and, to a lesser extent, increases strength with little loss in ductility; it adversely affects the hot-working characteristics and surface quality.

• Lead: improves machinability; it causes liquid-metal embrittlement.

• Magnesium: has the same effects as cerium.• Manganese: improves hardenability, strength, abrasion

resistance, and machinability; it deoxidizes the molten steel, reduce shot shortness, and decreases weldability.

• Molybdenum: improves hardenability, wear resistance, toughness, elevated-temperature strength, creep resistance, and hardness; it minimizes temper embrittlement.

Effects of Elements in Steels

• Nickel: improves strength, toughness, and corrosion resistance; it improves hardenability.

• Niobium (columbium): imparts fineness of grain size and improves strength and impact toughness; it lowers transition temperature and may decrease hardenability.

• Phosphorus: improves strength, hardenability, corrosion resistance, and machinability; it severely reduces ductility and toughness.

• Selenium: improves machinability.• Silicon: improves strength, hardness, corrosion

resistance, and electrical conductivity; it decreases magnetic-hysteresis loss, machinability, and cold formability.

Effects of Elements in Steels

• Sulfur: Improves machinability when combined with manganese; it lowers impact strength and ductility and impairs surface quality and weldability.

• Tantalum: has effects similar to those of niobium.• Tellurium: improves machinability, formability, and

toughness.• Titanium: improves hardenability; it deoxidizes steels.• Tungsten: has the same effects as cobalt.• Vanadium: improves strength, toughness, abrasion

resistance, and hardness at elevated temperatures; it inhibits grain growth during heat treatment.

• Zirconium: has the same effects as cerium