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Last class - MAR transformation Austenitization & tempering Stainless steels. Today - More stainless steels Tool steels Cast irons Case hardening. Types of steels. Plain carbon steels alloy steels Low carbon steels high carbon steels. Stainless steels. 420 13Cr-0.15C
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Last class - MAR transformation Austenitization & tempering Stainless steels Today - More stainless steels Tool steels Cast irons Case hardening
Types of steels Plain carbon steels alloy steels Low carbon steels high carbon steels Stainless steels 420 13Cr-0.15C 440A 17Cr-0.5Ni-0.7C 440C 17Cr-0.5Ni-1.2C 405 13Cr-0.5Ni-0.08C 430 16Cr-0.5Ni-0.12C 304 19Cr-10Ni-0.08C 304L 19Cr-10Ni-0.03C 316 17Cr-12Ni-0.08C 420 440A 440C 405 430 304 304L 316 420 13Cr-0.15C cutlery 440A 17Cr-0.5Ni-0.7C cutlery 440C 17Cr-0.5Ni-1.2C ball bearings 405 13Cr-0.5Ni-0.08C machine parts 430 16Cr-0.5Ni-0.12C acid tanks 304 19Cr-10Ni-0.08C food equipment 304L 19Cr-10Ni-0.03C food equipment 316 17Cr-12Ni-0.08C chemical tanks 420 13Cr-0.15C 230ksi(ht treated) 440A 17Cr-0.5Ni-0.7C 260ksi(ht treated) 440C 17Cr-0.5Ni-1.2C 285ksi(ht treated) 405 13Cr-0.5Ni-0.08C 60ksi(annealed) 430 16Cr-0.5Ni-0.12C 65ksi(annealed) 304 19Cr-10Ni-0.08C 85ksi(annealed) 304L 19Cr-10Ni-0.03C 80ksi(annealed) 316 17Cr-12Ni-0.08C 85ksi(annealed)
Types of steels Stainless steels
Stainless steels 420 13Cr-0.15C 230ksi(ht treated) 440A 17Cr-0.5Ni-0.7C 260ksi(ht treated) 440C 17Cr-0.5Ni-1.2C 285ksi(ht treated) 405 13Cr-0.5Ni-0.08C 60ksi(annealed) 430 16Cr-0.5Ni-0.12C 65ksi(annealed) 304 19Cr-10Ni-0.08C 85ksi(annealed) 304L 19Cr-10Ni-0.03C 80ksi(annealed) 316 17Cr-12Ni-0.08C 85ksi(annealed)
Stainless steels hardenable! not hardenable!
Stainless steels sufficient amt of Ni ––> AUS at rm temp austenitic SSs ----- ≥ 18% Cr & ≥ 8% Ni not hardenable
Types of steels Plain carbon steels alloy steels Low carbon steels high carbon steels Stainless steels Tool steels
Some types of tool steels W1, W2..... water hardening 0.60-1.40C S2, S2...... shock resisting 0.5C-Cr, W, Mo O1, O2..... oil hardening 0.9C-Mn, Ni, W A2, A3..... air hardening 1.25C-5Cr, V, Mo H10, H11..... hot work 0.4C-0.4V-3-5Cr T1, T2..... high-speed 0.8C-4Cr-18W-1-2V Compositions not exact - higher grades have different compositions
Speaking of tools….. Most are WC fragments imbedded in Co matrix angular WC fragments Co matrix phase - the "glue" What about "carbide" tools?
Speaking of tools….. OK, then, what about "ceramic" tools? Most from Al2O3 - pressed to near-net shape & sintered at 1600-1700° C - ground on diamond wheels At high temps, high hardness, wear resistance Can use for mat'ls w/ up to RC66 Very brittle Cost ≈ 2X that of carbide tools
Cast irons Types White - C is all in CM Grey - C as graphite flakes Ductile (nodular) - C as graphite nodules
Cast irons Grey - C as graphite ("corn") flakes Si added to graphitize, brittle cuz of flake stress raisers - cheap, widely used, vibration damping Ductile (nodular) - C as graphite nodules "inoculated" w/ Mg or Ce to get nodules - up to 40% EL White - C is all in CM very brittle, wear resistant, not machinable, limited use
Case hardening Gear tooth Carburizing - pack & gas - add C from CO gas