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Section 3.3 Ferrous and Nonferrous Metals

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Presentation on theme: "Section 3.3 Ferrous and Nonferrous Metals"— Presentation transcript:

1 Section 3.3 Ferrous and Nonferrous Metals
Rev. 4 8/20/01

2 Overview Ferrous Metals Nonferrous Metals Nonmetals

3 Part 1- Ferrous Metals

4 Ore Reduction Iron and steel have their start in the blast furnace.
Molten iron and slag are tapped off separately.

5 Pig Iron Pig refers to a crude casting for storage, transportation and remelting of any metal. Pig Iron refers to the composition of the metal tapped from the blast furnace - always contains 3%- 4% of carbon, and smaller amounts of silicon, sulfur, phosphorus, manganese, and other elements.

6 Cast Iron Cast iron is essentially pig iron with minor modifications of composition – 3% to 4% carbon and from 1% to 3% silicon. Wide variations in properties can be achieved by varying the balance between carbon and silicon. The four basic types of cast iron are white iron, gray iron, ductile iron, and malleable iron.

7 Wrought Iron Manufactured by pouring molten refined iron into separately manufactured slag with subsequent rolling. Tensile strength of 50,000 psi (350 Mpa), good ductility, and anisotropic (properties vary with orientation).

8 Steel Making Early Steel
Reheating wrought iron and powdered charcoal together in the cementation process Carbon in not uniformly dispersed throughout the material and multiple cutting and re-rolling procedures are needed

9 Steel Making Processes
Crucible Steel Open Hearth Steel Bessemer Steel Electric Furnace Steel

10 Steel Making Basic Oxygen Steel
Molten pig iron is charged on top of the scrap. High velocity jet oxygen is blown into top of the molten mixture for about 20 minutes. Lime and various fluxes are added to control composition. The metal is sampled and if acceptable, is poured through the vessel tap hole into the ladle. Vessel is tipped to empty the slag from the top of the vessel.

11 Classification of Steels
4 Defined classes of steel (AISI): Carbon Steel Alloy Steel Stainless Steel Tool Steel

12 Types of Carbon Steel Euctoid carbon steel: 0.75-0.85% carbon.
Hypoeutectoid carbon steel: <0.77% carbon. Hypereutecoid carbon steel: % carbon.

13 Alloy Steels Various chemical elements are added to improve hardenability, weldability, grain size, toughness, and corrosion resistance. Elements include: Si, Ni, Cr, and Mo.

14 Stainless Steels Classifications of Stainless Steels: Martensitic
Ferritic Austenitic

15 Stainless Steels Martensitic Ferritic Chromium content usually 4 – 6%.
Silicon or aluminum added to some chromium steels. Ferritic Chromium content 30% or more. Austenite is suppressed. Normal steel heat-treating processing does not harden.

16 Stainless Steels Austenitic
High chromium and the addition of 8% or more of nickel (or combinations of nickel and mangenese) suppress ferrite Most typical austenitic steel contains 18% chromium and 8% nickel

17 Tool and Die Steels Majority are made from plain carbon or low alloy steels. Manganese tool and die steels contain carbon, 1.5% to 1.75% of manganese, and small amounts of chromium, vanadium, and molybdenum. Chromium tool and die steels have high chromium and may also include tungsten, vanadium, and cobalt.

18 Part 2 - Nonferrous Metals

19 Light Metals and Alloys
Materials whose density is less than steel: Aluminum Magnesium, Titanium, and Beryllium.

20 Aluminum Alloys Aluminum is the most important structural nonferrous metal. Tensile strengths range from 12,000 to 80,000 psi (83 to 550 Mpa). Excellent ductility, corrosion resistance, and conductivity.

21 Aluminum Alloys Endurance limit - even for hardened alloys is in the low range of 5,000 to 20,000 psi. Lower Strength at higher temperature. Typicall alloying elements include magnesium, copper, silicon, manganese, zinc, nickel, and chromium.

22 Magnesium Alloys Tensile Strengths up to 50,000 psi for wrought alloys, up to 40,000 psi for cast alloys. Good corrosion resistance for ordinary atmosphere, although surface protection in severe applications is required.

23 Magnesium Alloys Limitations High cost of recovery from sea water.
Notch sensitivity - low impact strength. High rate of strain hardening requires that most forming operations must be done hot.

24 Titanium Low-density element (approx. 60% of the density of steel).
High strengths can be achieved by alloying and deformation processing. Excellent for use in corrosion-resistant service and strength-efficient structures.

25 Beryllium High strength, lightweight, often used in aerospace applications. Maintains some strength up to 593 degrees C (1100 deg. F).

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

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

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

29 Brasses and Bronzes Brass: zinc is the principle alloying element
Bronze: tin is the principle alloying element

30 Copper Alloys Copper Nickels/Nickel Silvers
Nickel is the primary alloying element.

31 Zinc Alloys Low cost, but low strength.
Good corrosion resistance when used as a coating on ferrous materials (galvanizing) High formability - excellent roofing material, dry cell battery cases

32 Part 3 - Nonmetals

33 Polymers Polymers are “built” from chemical units called monomers.
Always composed of atoms of carbon in combination with other elements such as: Hydrogen Nitrogen Oxygen Silicon Chlorine

34 Plastics Chemically, all plastics are polymers whose exact properties depend on the degree of polymerization. May be classified as either: Thermosetting, or Thermoplastic.

35 Thermosets “Heat-set”.
Polymer chains undergo three dimensional chain combination by cross-linking. These chains are joined irreversibly during molding into an interconnected, molecular network. Cannot be remolded.

36 Thermoplastics “Heat-Flowable”.
Polymer chains remain linear and separate after molding. Can be remolded again and again.

37 Characteristics of Plastics
Thermoplastics Lower in strength and hardness but higher in toughness than thermosets. Thermosets Better moisture and chemical resistance than thermoplastics.

38 Ceramics Applies to wide range of materials, although those used as structural engineering materials include a only a handful of types. Characterized as: Brittle, Having a high melting temperature, Being a poor conductor of electricity, and Nonmagnetic.

39 Composites A resin-matrix reinforced with high-strength, high modulus fibers such as: Glass, Carbon, Aramid, or Boron. Usually laid up in a multilayer fashion, to form extremely rugged, strong structures.


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