EBB113 METALS ALLOYS

Metal Alloys Ferrous SteelCast Iron Low AlloyHigh Alloy Non Ferrous Fe 3 C cementite L  austenite  +L+L  +Fe 3 C  ferrite  +Fe 3 C  +  L+Fe 3 C  (Fe) C o, wt% C Eutectic: Eutectoid: °C 1148°C T(°C) Cu Mg Al Ti

Steels Low Alloy High Alloy low carbon <0.25 wt% C Med carbon wt% C high carbon wt% C Usesauto struc. sheet bridges towers press. vessels crank shafts bolts hammers blades pistons gears wear applic. wear applic. drills saws dies high T applic. turbines furnaces V. corros. resistant Example Additionsnone Cr,V Ni, Mo none Cr, Ni Mo none Cr, V, Mo, W Cr, Ni, Mo plainHSLAplain heat treatable plaintool austenitic stainless Name Hardenability TS EL increasing strength, cost, decreasing ductility Steels are iron-carbon alloys Mechanical properties are a function of carbon content and other alloying elements + satisfactory, ++good, +++ very good

Low Carbon Steel Alloys of low carbon steel being produced in the greatest quantity Alloys of low carbon steel being produced in the greatest quantity < 0.25wt %C < 0.25wt %C Consists of ferrites and pearlites hence soft and weak but can be treated to achieve high strength Consists of ferrites and pearlites hence soft and weak but can be treated to achieve high strength Machinable, weldable and cheaper to be produced Machinable, weldable and cheaper to be produced Types: Types: –i. plain low carbon steel - no alloying, variable tensile strength (TS) ( MPa and Yield Strength (YS)= 275MPa Applications – crankshafts, bolts, hammers, hand tools, gears, knives Applications – crankshafts, bolts, hammers, hand tools, gears, knives –ii. High strength low alloy (HSLA) – with alloying, higher TS and YS Applications – automobiles opines, nails, wire, pipe structural and sheet steel, railway cars Applications – automobiles opines, nails, wire, pipe structural and sheet steel, railway cars

Medium Carbon Steel 0.25 – 0.6 wt %C 0.25 – 0.6 wt %C Heat treated to achieve good mechanical properties Heat treated to achieve good mechanical properties Used in tampered condition (tampered martinsitic) Used in tampered condition (tampered martinsitic) Strength -ductility combination can be tailored by heat treatment and alloying (with Ni, Cr and Mo) Strength -ductility combination can be tailored by heat treatment and alloying (with Ni, Cr and Mo) Applications: high strength structural components – railway wheels, tracks, crankshafts Applications: high strength structural components – railway wheels, tracks, crankshafts

High Carbon Steel 0.6 – 1.4 wt %C 0.6 – 1.4 wt %C Hardest, strongest and least ductile carbon steel Hardest, strongest and least ductile carbon steel Used in harden and tempered conditions Used in harden and tempered conditions Can be alloyed with carbon and other metals to form vary hard and wear resistance material (e.g. C, Cr, Ni, W, Mo and V) Can be alloyed with carbon and other metals to form vary hard and wear resistance material (e.g. C, Cr, Ni, W, Mo and V) Applications: cutting tools, drills, saws, embossing dies, cutlery, paper cutters, concrete drill, blacksmith tools Applications: cutting tools, drills, saws, embossing dies, cutlery, paper cutters, concrete drill, blacksmith tools

Stainless-Steels Highly resistance alloy to corrosion (rusting) in a variety of environment. Mechanical integrity maintains. Highly resistance alloy to corrosion (rusting) in a variety of environment. Mechanical integrity maintains. Consisting of iron-carbon and chromium (> 11 wt% Cr needed) Consisting of iron-carbon and chromium (> 11 wt% Cr needed) Add nickel and molybdenum as well Add nickel and molybdenum as well Example 0.08 C, 11.0 Cr, 1.Mn, 0.50 Ni, 0.75 Ti : S40900 Example 0.08 C, 11.0 Cr, 1.Mn, 0.50 Ni, 0.75 Ti : S40900 Examples of use of stainless-steel: Examples of use of stainless-steel:

Cast Irons 3.0 – 4.5wt % C Liquid at 1150 – 1300 o C Easily melted and amenable to casting

Cast Irons Gray iron graphite flakes graphite flakes weak & brittle under tension weak & brittle under tension stronger under compression stronger under compression excellent vibrational dampening excellent vibrational dampening wear resistant wear resistant Ductile iron add Mg or Ce add Mg or Ce graphite in nodules not flakes graphite in nodules not flakes matrix often pearlite - better ductility matrix often pearlite - better ductility

True & False (on Ferrous Metals) 1. Stainless steel consists of iron-carbon and chromium 2. Low carbon steel is characterized by high hardness 3. Medium carbon steel is often applied for high strength structural components 4. Higher carbon steel is weak and ductile 5. Due to its high hardness, high carbon steel can be used to make concrete drill, blacksmith tools 6. Cast irons are 6. Cast irons are difficult to be melted Login socrative.com Room name: syahriza ACTIVITY (1)

ANSWERS 1. Stainless steel consists of iron-carbon and chromium - T 2. Low carbon steel is characterized by high hardness - F 3. Medium carbon steel is often applied for high strength structural components 4. Higher carbon steel is weak and ductile - F 5. Cast irons are 5. Cast irons are easier to be melted

Make a mind map: ferrous and non- ferrous metal Login to: Discussion (1):

Discussion (2): Limitations of Ferrous Alloys. Discuss the statements below: 1)Relatively high density 2)Relatively low conductivity 3)Poor corrosion resistance Login to: Login to: