Chapters 5 and 6: Ferrous and Nonferrous Metals

1. Chapters 5 and 6: Ferrous and Nonferrous Metals Group 5 Patrick Pace Michael Linley Bryan Estvanko Matthew Sallee

2. CHAPTER 5 5.1-5.4 Ferrous Metals and Alloys Production - General Properties - Application

3. Introduction • What is a ‘ferrous metal’ or ‘ferrous alloy’? It is simply a metal or alloy that contains Iron (the element ferrous) as the base (starting) metal. • 26th element  • Iron or Ferrous  55.85 Atomic Mass

4. General Categories of Ferrous Metals and Alloys • Carbon and alloy steels • Stainless steel • Tool and Die steel • Cast Irons • Cast Steels • **Ferrous tools first appear about 4000 to 3000 BC, made from meteoritic iron. Real ironworking started in about 1100 BC in Asia Minor, and started the Iron Age.

5. APPLICATION OF FERROUS (IRON) METALS / ALLOYS

6. 5.2 Production of Iron and Steel

7. Raw Materials for Production • Iron Ore • Limestone ---------- • Coke

8. 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.

9. 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.

10. 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.

11. Ironmaking

12. 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.

13. Blast Furnace Tuyeres (Same height as a 10 story building)

14. Steelmaking

15. 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)

16. Open-Hearth Furnace Uses a fuel to generate heat, and melt the metal.

17. 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.

18. 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

19. 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.

20. 5.3 Casting Ingots

21. 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.

22. 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.

23. 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.

24. 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

25. 5.4 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.

26. Benefits of Continuous Casting • Costs less to produce final product • Metal has more uniform composition and properties than ingot processing.

27. Sections 5.5 - 5.7 Carbon and Alloying Steel Stainless Steels Tool and Die Steels

28. 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.

29. 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.

30. 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.

31. 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.

32. 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.

33. 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

34. Residual Elements • During the processing of steels some residual elements remain in the medal. • 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

35. Carbon Steels • Carbon steels are group by their percentage of carbon content per weight. The higher the carbon content the greater the hardness, strength and wear resistance after heat treatment. • Low-carbon steel, also called mild steels, has less than 0.30% carbon. Used in everyday industrial products like bolts, nuts, sheet, plate and tubes. High Carbon Steel Nails

36. Carbon Steels • Medium-carbon steel has 0.30% to 0.60% carbon. Used for jobs requiring higher strength such as machinery, automotive equipment parts, and metalworking equipment. • High-carbon steel has more than 0.60% carbon. Used parts that require the highest strength, hardness, and wear resistance. Once manufactured they are heat treated and tempered

37. Alloy Steels • Alloy steels are steels that contain significant amounts of alloying elements. • High strength low alloy steels • Microalloyed steels • Nanoalloyed steels

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

39. 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.

40. Stainless Steels • Stainless steels are primarily know for their corrosion resistance, high strength, and ductility and chromium content.

41. 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.

42. 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.

43. 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

44. 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

45. 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

46. 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.

47. Chapter 6: Nonferrous Metals and Alloys • 6.1 Introduction • 6.2 Aluminum • 6.3 Magnesium • 6.4 Copper • 6.5 Nickel • 6.6 Superalloys • 6.7 Titanium • 6.8 Refractory Metals

48. Introduction • Nonferrous metals and alloys • Common- aluminum, copper, and magnesium • High-strength high-temperature alloys include: tungsten, tantalum, and molybdenum. • Higher cost than ferrous metals but have good properties such as: • Corrosion resistance • High thermal and electrical conductivity • Low density and ease of fabrication

49. Aluminum and Aluminum Alloys • Most abundant metallic element (8% crust) • High strength to weight ratio • Resistant to corrosion • High thermal and electrical conductivity • Nonmagnetic • Easy formability and machinability

50. UNS • UNS-Unified Numbering System • A common system used everywhere to describe the condition of a metal or an alloy. • Generally has 4 numbers and a temper designation • Temper designation tells the condition of the material. • Example: 2024 wrought aluminum is A92024