last class - mar transformation austenitization & tempering stainless steels last class - mar...

Last class -

MAR transformationAustenitization & temperingStainless steels

Last class -

MAR transformationAustenitization & temperingStainless steels

Today -

More stainless steelsTool steelsCast ironsCase hardening

Today -

More stainless steelsTool steelsCast ironsCase hardening

Types of steels Types of steels Plain carbon steels alloy steelsLow carbon steels high carbon steels

Plain carbon steels alloy steelsLow carbon steels high carbon steelsStainless steels Stainless steels

420440A440C

405430

304304L316

420440A440C

405430

304304L316

420 13Cr-0.15C440A 17Cr-0.5Ni-0.7C440C 17Cr-0.5Ni-1.2C

405 13Cr-0.5Ni-0.08C430 16Cr-0.5Ni-0.12C

304 19Cr-10Ni-0.08C304L 19Cr-10Ni-0.03C316 17Cr-12Ni-0.08C

420 13Cr-0.15C440A 17Cr-0.5Ni-0.7C440C 17Cr-0.5Ni-1.2C

405 13Cr-0.5Ni-0.08C430 16Cr-0.5Ni-0.12C

304 19Cr-10Ni-0.08C304L 19Cr-10Ni-0.03C316 17Cr-12Ni-0.08C

420 13Cr-0.15C cutlery440A 17Cr-0.5Ni-0.7C cutlery440C 17Cr-0.5Ni-1.2C ball bearings

405 13Cr-0.5Ni-0.08C machine parts430 16Cr-0.5Ni-0.12C acid tanks

304 19Cr-10Ni-0.08C food equipment304L 19Cr-10Ni-0.03C food equipment316 17Cr-12Ni-0.08C chemical tanks

420 13Cr-0.15C cutlery440A 17Cr-0.5Ni-0.7C cutlery440C 17Cr-0.5Ni-1.2C ball bearings

405 13Cr-0.5Ni-0.08C machine parts430 16Cr-0.5Ni-0.12C acid tanks

304 19Cr-10Ni-0.08C food equipment304L 19Cr-10Ni-0.03C food equipment316 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 Types of steels

Stainless steels Stainless steels







Stainless steelsStainless steels


hardenable!

not hardenable!


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 Types of steels Plain carbon steels alloy steelsLow carbon steels high carbon steelsStainless steels

Plain carbon steels alloy steelsLow carbon steels high carbon steelsStainless steelsTool steelsTool steels

Some types of 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

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….. Speaking of tools…..

What about "carbide" tools?What about "carbide" tools?

Most are WC fragments imbedded in Co matrixMost are WC fragments imbedded in Co matrix

angular WC fragmentsangular WC fragments

Co matrix phase - the "glue"

Co matrix phase - the "glue"

Speaking of tools….. Speaking of tools…..

OK, then, what about "ceramic" tools?OK, then, what about "ceramic" tools?

Most from Al2O3 - pressed to near-net shape & sintered at 1600-1700° C - ground on diamond wheels

Most from Al2O3 - pressed to near-net shape & sintered at 1600-1700° C - ground on diamond wheels

At high temps, high hardness, wear resistanceCan use for mat'ls w/ up to RC66

At high temps, high hardness, wear resistanceCan use for mat'ls w/ up to RC66

Very brittleCost ≈ 2X that of carbide toolsVery brittleCost ≈ 2X that of carbide tools

Cast irons Cast irons

TypesWhite - C is all in CMGrey - C as graphite flakesDuctile (nodular) - C as graphite

nodules

TypesWhite - C is all in CMGrey - C as graphite flakesDuctile (nodular) - C as graphite

nodules


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 useGrey - 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 hardeningCase hardening

Gear toothGear tooth

Carburizing - pack & gas - add C from CO gasCarburizing - pack & gas - add C from CO gas

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