Section 3.3Section 3.3

Ferrous and Nonferrous Ferrous and Nonferrous MetalsMetals

Rev. 4Rev. 4

8/20/018/20/01

OverviewOverview

Ferrous MetalsFerrous Metals Nonferrous MetalsNonferrous Metals NonmetalsNonmetals

Part 1- Ferrous MetalsPart 1- Ferrous Metals

Ore ReductionOre Reduction

Iron and steel have their start in the Iron and steel have their start in the blast furnace.blast furnace.

Molten iron and slag are tapped off Molten iron and slag are tapped off separately.separately.

Pig IronPig Iron

Pig refers to a crude casting for storage, Pig refers to a crude casting for storage, transportation and remelting of any transportation and remelting of any metal.metal.

Pig Iron refers to the composition of the Pig Iron refers to the composition of the metal tapped from the blast furnace - metal tapped from the blast furnace - always contains 3%- 4% of carbon, and always contains 3%- 4% of carbon, and smaller amounts of silicon, sulfur, smaller amounts of silicon, sulfur, phosphorus, manganese, and other phosphorus, manganese, and other elements.elements.

Cast IronCast Iron

Cast iron is essentially pig iron with minor Cast iron is essentially pig iron with minor modifications of composition – 3% to 4% modifications of composition – 3% to 4% carbon and from 1% to 3% silicon. carbon and from 1% to 3% silicon.

Wide variations in properties can be Wide variations in properties can be achieved by varying the balance between achieved by varying the balance between carbon and silicon.carbon and silicon.

The four basic types of cast iron are white The four basic types of cast iron are white iron, gray iron, ductile iron, and malleable iron, gray iron, ductile iron, and malleable iron.iron.

Wrought IronWrought Iron

Manufactured by pouring molten refined Manufactured by pouring molten refined iron into separately manufactured slag iron into separately manufactured slag with subsequent rolling.with subsequent rolling.

Tensile strength of 50,000 psi (350 Tensile strength of 50,000 psi (350 Mpa), good ductility, and anisotropic Mpa), good ductility, and anisotropic (properties vary with orientation).(properties vary with orientation).

Steel Making Steel Making

Early SteelEarly Steel– Reheating wrought iron and powdered Reheating wrought iron and powdered

charcoal together in the cementation charcoal together in the cementation processprocess

– Carbon in not uniformly dispersed Carbon in not uniformly dispersed throughout the material and multiple cutting throughout the material and multiple cutting and re-rolling procedures are neededand re-rolling procedures are needed

Steel Making Processes Steel Making Processes

Crucible SteelCrucible Steel Open Hearth SteelOpen Hearth Steel Bessemer SteelBessemer Steel Electric Furnace SteelElectric Furnace Steel

Steel MakingSteel Making

Basic Oxygen SteelBasic Oxygen Steel– Molten pig iron is charged on top of the scrap.Molten pig iron is charged on top of the scrap.– High velocity jet oxygen is blown into top of High velocity jet oxygen is blown into top of

the molten mixture for about 20 minutes. the molten mixture for about 20 minutes. – Lime and various fluxes are added to control Lime and various fluxes are added to control

composition.composition.– The metal is sampled and if acceptable, is The metal is sampled and if acceptable, is

poured through the vessel tap hole into the poured through the vessel tap hole into the ladle.ladle.

– Vessel is tipped to empty the slag from the top Vessel is tipped to empty the slag from the top of the vessel.of the vessel.

Classification of SteelsClassification of Steels

4 Defined classes of steel (AISI):4 Defined classes of steel (AISI):– Carbon SteelCarbon Steel– Alloy SteelAlloy Steel– Stainless SteelStainless Steel– Tool SteelTool Steel

Types of Carbon SteelTypes of Carbon Steel

Euctoid Euctoid carbon steel: 0.75-0.85% carbon steel: 0.75-0.85% carbon.carbon.

HypoeutectoidHypoeutectoid carbon steel: <0.77% carbon steel: <0.77% carbon.carbon.

HypereutecoidHypereutecoid carbon steel: 0.77-2.0% carbon steel: 0.77-2.0% carbon.carbon.

Alloy SteelsAlloy Steels

Various chemical elements are added to Various chemical elements are added to improve hardenability, weldability, grain improve hardenability, weldability, grain size, toughness, and corrosion size, toughness, and corrosion resistance.resistance.

Elements include:Elements include:– Si,Si,– Ni,Ni,– Cr, andCr, and– Mo.Mo.

Stainless SteelsStainless Steels

Classifications of Stainless Steels:Classifications of Stainless Steels:– Martensitic Martensitic – FerriticFerritic– AusteniticAustenitic

Stainless SteelsStainless Steels

Martensitic Martensitic – Chromium content usually 4 – 6%.Chromium content usually 4 – 6%.– Silicon or aluminum added to some Silicon or aluminum added to some

chromium steels.chromium steels. FerriticFerritic

– Chromium content 30% or more.Chromium content 30% or more.– Austenite is suppressed.Austenite is suppressed.– Normal steel heat-treating processing does Normal steel heat-treating processing does

not harden.not harden.

Stainless SteelsStainless Steels

AusteniticAustenitic– High chromium and the addition of 8% or High chromium and the addition of 8% or

more of nickel (or combinations of nickel more of nickel (or combinations of nickel and mangenese) suppress ferriteand mangenese) suppress ferrite

– Most typical austenitic steel contains 18% Most typical austenitic steel contains 18% chromium and 8% nickelchromium and 8% nickel

Tool and Die SteelsTool and Die Steels

Majority are made from plain carbon or Majority are made from plain carbon or low alloy steels.low alloy steels.

Manganese tool and die steels contain Manganese tool and die steels contain carbon, 1.5% to 1.75% of manganese, carbon, 1.5% to 1.75% of manganese, and small amounts of chromium, and small amounts of chromium, vanadium, and molybdenum.vanadium, and molybdenum.

Chromium tool and die steels have high Chromium tool and die steels have high chromium and may also include chromium and may also include tungsten, vanadium, and cobalt.tungsten, vanadium, and cobalt.

Part 2 - Nonferrous MetalsPart 2 - Nonferrous Metals

Light Metals and AlloysLight Metals and Alloys

Materials whose density is less than Materials whose density is less than steel:steel:– AluminumAluminum– Magnesium,Magnesium,– Titanium, andTitanium, and– Beryllium.Beryllium.

Aluminum AlloysAluminum Alloys

Aluminum is the most important Aluminum is the most important structural nonferrous metal. structural nonferrous metal.

Tensile strengths range from 12,000 to Tensile strengths range from 12,000 to 80,000 psi (83 to 550 Mpa).80,000 psi (83 to 550 Mpa).

Excellent ductility, corrosion resistance, Excellent ductility, corrosion resistance, and conductivity.and conductivity.

Aluminum AlloysAluminum Alloys

Endurance limit - even for hardened Endurance limit - even for hardened alloys is in the low range of 5,000 to alloys is in the low range of 5,000 to 20,000 psi.20,000 psi.

Lower Strength at higher temperature.Lower Strength at higher temperature. Typicall alloying elements include Typicall alloying elements include

magnesium, copper, silicon, magnesium, copper, silicon, manganese, zinc, nickel, and chromium.manganese, zinc, nickel, and chromium.

Magnesium AlloysMagnesium Alloys

Tensile Strengths up to 50,000 psi for Tensile Strengths up to 50,000 psi for wrought alloys, up to 40,000 psi for cast wrought alloys, up to 40,000 psi for cast alloys.alloys.

Good corrosion resistance for ordinary Good corrosion resistance for ordinary atmosphere, although surface atmosphere, although surface protection in severe applications is protection in severe applications is required.required.

Magnesium AlloysMagnesium Alloys

LimitationsLimitations– High cost of recovery from sea water.High cost of recovery from sea water.– Notch sensitivity - low impact strength.Notch sensitivity - low impact strength.– High rate of strain hardening requires that High rate of strain hardening requires that

most forming operations must be done hot. most forming operations must be done hot.

TitaniumTitanium

Low-density element (approx. 60% of Low-density element (approx. 60% of the density of steel).the density of steel).

High strengths can be achieved by High strengths can be achieved by alloying and deformation processing.alloying and deformation processing.

Excellent for use in corrosion-resistant Excellent for use in corrosion-resistant service and strength-efficient structures.service and strength-efficient structures.

BerylliumBeryllium

High strength, lightweight, often used in High strength, lightweight, often used in aerospace applications.aerospace applications.

Maintains some strength up to 593 Maintains some strength up to 593 degrees C (1100 deg. F).degrees C (1100 deg. F).

Copper & Copper AlloysCopper & Copper Alloys

Commonly divided into six categories:Commonly divided into six categories:– Coppers,Coppers,– Dilute Copper Alloys,Dilute Copper Alloys,– Brasses,Brasses,– Bronzes,Bronzes,– Copper nickels, andCopper nickels, and– Nickel silvers.Nickel silvers.

CoppersCoppers

Essentially pure copper.Essentially pure copper. Soft and ductile.Soft and ductile. Contains less than 0.7% impurities.Contains less than 0.7% impurities.

Dilute Copper AlloysDilute Copper Alloys

Contains small amounts of various Contains small amounts of various alloying elements that modify one or alloying elements that modify one or more of the basic properties of copper.more of the basic properties of copper.

Brasses and BronzesBrasses and Bronzes

Brass: zinc is the principle alloying Brass: zinc is the principle alloying elementelement

Bronze: tin is the principle alloying Bronze: tin is the principle alloying elementelement

Copper AlloysCopper Alloys

Copper Nickels/Nickel SilversCopper Nickels/Nickel Silvers– Nickel is the primary alloying element.Nickel is the primary alloying element.

Zinc AlloysZinc Alloys

Low cost, but low strength.Low cost, but low strength. Good corrosion resistance when used Good corrosion resistance when used

as a coating on ferrous materials as a coating on ferrous materials (galvanizing)(galvanizing)

High formability - excellent roofing High formability - excellent roofing material, dry cell battery casesmaterial, dry cell battery cases

Part 3 - Nonmetals Part 3 - Nonmetals

PolymersPolymers

Polymers are “built” from chemical units Polymers are “built” from chemical units called monomers.called monomers.

Always composed of atoms of carbon in Always composed of atoms of carbon in combination with other elements such as:combination with other elements such as:– HydrogenHydrogen– NitrogenNitrogen– OxygenOxygen– SiliconSilicon– ChlorineChlorine

PlasticsPlastics

Chemically, all plastics are polymers Chemically, all plastics are polymers whose exact properties depend on the whose exact properties depend on the degree of polymerization.degree of polymerization.

May be classified as either:May be classified as either:– Thermosetting, orThermosetting, or– Thermoplastic.Thermoplastic.

ThermosetsThermosets

““Heat-set”.Heat-set”. Polymer chains undergo three Polymer chains undergo three

dimensional chain combination by dimensional chain combination by cross-linking.cross-linking.

These chains are joined irreversibly These chains are joined irreversibly during molding into an interconnected, during molding into an interconnected, molecular network.molecular network.

Cannot be remolded.Cannot be remolded.

ThermoplasticsThermoplastics

““Heat-Flowable”.Heat-Flowable”. Polymer chains remain linear and Polymer chains remain linear and

separate after molding.separate after molding. Can be remolded again and again.Can be remolded again and again.

Characteristics of PlasticsCharacteristics of Plastics

ThermoplasticsThermoplastics– Lower in strength and hardness but higher Lower in strength and hardness but higher

in toughness than thermosets.in toughness than thermosets. ThermosetsThermosets

– Better moisture and chemical resistance Better moisture and chemical resistance than thermoplastics.than thermoplastics.

CeramicsCeramics

Applies to wide range of materials, Applies to wide range of materials, although those used as structural although those used as structural engineering materials include a only a engineering materials include a only a handful of types.handful of types.

Characterized as:Characterized as:– Brittle,Brittle,– Having a high melting temperature,Having a high melting temperature,– Being a poor conductor of electricity, andBeing a poor conductor of electricity, and– Nonmagnetic.Nonmagnetic.

CompositesComposites

A resin-matrix reinforced with high-A resin-matrix reinforced with high-strength, high modulus fibers such as:strength, high modulus fibers such as:– Glass,Glass,– Carbon,Carbon,– Aramid, orAramid, or– Boron. Boron.

Usually laid up in a multilayer fashion, to Usually laid up in a multilayer fashion, to form extremely rugged, strong form extremely rugged, strong structures.structures.