Last class - MAR transformation Austenitization & tempering Stainless steels Last class - MAR transformation Austenitization & tempering Stainless steels Today - More stainless steels Tool steels Cast irons Case hardening Today - More stainless steels Tool steels Cast irons Case hardening

Types of steels Plain carbon steels alloy steels Low carbon steels high carbon steels Plain carbon steels alloy steels Low carbon steels high carbon steels Stainless steels A 440C L A 440C L Cr-0.15C 440A 17Cr-0.5Ni-0.7C 440C 17Cr-0.5Ni-1.2C Cr-0.5Ni-0.08C Cr-0.5Ni-0.12C Cr-10Ni-0.08C 304L 19Cr-10Ni-0.03C Cr-12Ni-0.08C Cr-0.15C 440A 17Cr-0.5Ni-0.7C 440C 17Cr-0.5Ni-1.2C Cr-0.5Ni-0.08C Cr-0.5Ni-0.12C Cr-10Ni-0.08C 304L 19Cr-10Ni-0.03C Cr-12Ni-0.08C Cr-0.15C cutlery 440A 17Cr-0.5Ni-0.7C cutlery 440C 17Cr-0.5Ni-1.2C ball bearings Cr-0.5Ni-0.08C machine parts Cr-0.5Ni-0.12C acid tanks Cr-10Ni-0.08C food equipment 304L 19Cr-10Ni-0.03C food equipment Cr-12Ni-0.08C chemical tanks Cr-0.15C cutlery 440A 17Cr-0.5Ni-0.7C cutlery 440C 17Cr-0.5Ni-1.2C ball bearings Cr-0.5Ni-0.08C machine parts Cr-0.5Ni-0.12C acid tanks Cr-10Ni-0.08C food equipment 304L 19Cr-10Ni-0.03C food equipment Cr-12Ni-0.08C chemical tanks Cr-0.15C 230ksi(ht treated) 440A 17Cr-0.5Ni-0.7C 260ksi(ht treated) 440C 17Cr-0.5Ni-1.2C 285ksi(ht treated) Cr-0.5Ni-0.08C 60ksi(annealed) Cr-0.5Ni-0.12C 65ksi(annealed) Cr-10Ni-0.08C 85ksi(annealed) 304L 19Cr-10Ni-0.03C 80ksi(annealed) Cr-12Ni-0.08C 85ksi(annealed) Cr-0.15C 230ksi(ht treated) 440A 17Cr-0.5Ni-0.7C 260ksi(ht treated) 440C 17Cr-0.5Ni-1.2C 285ksi(ht treated) Cr-0.5Ni-0.08C 60ksi(annealed) Cr-0.5Ni-0.12C 65ksi(annealed) Cr-10Ni-0.08C 85ksi(annealed) 304L 19Cr-10Ni-0.03C 80ksi(annealed) Cr-12Ni-0.08C 85ksi(annealed)

Types of 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) Cr-0.5Ni-0.08C 60ksi(annealed) Cr-0.5Ni-0.12C 65ksi(annealed) Cr-10Ni-0.08C 85ksi(annealed) 304L 19Cr-10Ni-0.03C 80ksi(annealed) Cr-12Ni-0.08C 85ksi(annealed) Cr-0.15C 230ksi(ht treated) 440A 17Cr-0.5Ni-0.7C 260ksi(ht treated) 440C 17Cr-0.5Ni-1.2C 285ksi(ht treated) Cr-0.5Ni-0.08C 60ksi(annealed) Cr-0.5Ni-0.12C 65ksi(annealed) Cr-10Ni-0.08C 85ksi(annealed) 304L 19Cr-10Ni-0.03C 80ksi(annealed) Cr-12Ni-0.08C 85ksi(annealed) Stainless steels

hardenable! not hardenable!

Stainless steels austenitic SSs ≥ 18% Cr & ≥ 8% Ni not hardenable austenitic SSs ≥ 18% Cr & ≥ 8% Ni not hardenable sufficient amt of Ni ––> AUS at rm temp

Types of steels Plain carbon steels alloy steels Low carbon steels high carbon steels Stainless steels Plain carbon steels alloy steels Low carbon steels high carbon steels Stainless steels Tool steels

Some types of tool steels W1, W water hardening C S2, S shock resisting 0.5C-Cr, W, Mo O1, O oil hardening 0.9C-Mn, Ni, W A2, A air hardening 1.25C-5Cr, V, Mo H10, H hot work 0.4C-0.4V-3-5Cr T1, T high-speed 0.8C-4Cr-18W-1-2V Compositions not exact - higher grades have different compositions W1, W water hardening C S2, S shock resisting 0.5C-Cr, W, Mo O1, O oil hardening 0.9C-Mn, Ni, W A2, A air hardening 1.25C-5Cr, V, Mo H10, H hot work 0.4C-0.4V-3-5Cr T1, T high-speed 0.8C-4Cr-18W-1-2V Compositions not exact - higher grades have different compositions

Speaking of tools….. What about "carbide" tools? Most are WC fragments imbedded in Co matrix angular WC fragments Co matrix phase - the "glue" Co matrix phase - the "glue"

Speaking of tools….. OK, then, what about "ceramic" tools? Most from Al 2 O 3 - pressed to near-net shape & sintered at ° C - ground on diamond wheels At high temps, high hardness, wear resistance Can use for mat'ls w/ up to R C 66 At high temps, high hardness, wear resistance Can use for mat'ls w/ up to R C 66 Very brittle Cost ≈ 2X that of carbide tools 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 Types White - C is all in CM Grey - C as graphite flakes Ductile (nodular) - C as graphite nodules

Cast irons

White - C is all in CM very brittle, wear resistant, not machinable, limited use White - C is all in CM very brittle, wear resistant, not machinable, limited use Grey - C as graphite ("corn") flakes Si added to graphitize, brittle cuz of flake stress raisers - cheap, widely used, vibration damping 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 Ductile (nodular) - C as graphite nodules "inoculated" w/ Mg or Ce to get nodules - up to 40% EL

Case hardening Gear tooth Carburizing - pack & gas - add C from CO gas