Machine Drawing

Annexure 443

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Table 3 Recommended heat treatment data for carbon and alloy steels

Hot working

Designation of temperature Normalising Hardening Quenching Tempering

steel °C °C °C °C

30C8 1200–850 860–890 860–890 Water or oil 550–660

35C8 1200–850 850–880 840–880 Water or oil 530–760

40C8 1200–850 830–860 830–860 Water or oil 550–660

45C8 1200–850 830–860 830–860 Water or oil 530–670

50C8 1150–850 810–840 810–840 Oil 550–660

55C8 1150–850 810–840 810–840 Oil 550–660

40C10S18 1200–850 830–860 830–860 Oil 550–660

40Mn2S12 1200–850 840–870 840–870 Oil 550–660

20C15 1200–850 860–900 860–900 Water or oil 550–660

27C15 1200–850 840–880 840–880 Water or oil 550–660

37C15 1200–850 850–870 850–870 Water or oil 550–660

40Cr4 1200–850 850–880 850–880 Oil 550–700

35Mn6Mo3 1200–900 — 840–860 Water or oil 550–600

35Mn6Mo4 1200–900 — 840–860 Oil 550–660

40Cr4Mo3 1200–850 850–880 850–880 Oil 550–720

40Cr13Mo10V2 1200–850 – 900–940 Oil 570–650

40Cr7A110Mo2 1200–850 – 850–900 Oil 550–700

40Ni14 1200–850 830–860 830–860 Oil 550–650

35Ni10Cr3Mo6 1200–850 — 830–850 Oil Up to 660

40Ni10Cr3Mo6 1200–850 — 830–850 Oil Up to 660

40Ni6Cr4Mo2 1200–850 — 830–850 Oil 550–660

40Ni6Cr4Mo3 1200–850 — 830–850 Oil 150–200 or

550–660

35Ni3Cr5 1200–850 — 810–830 Air or Oil 250

Table 4 Hardness obtained by Induction/Flame hardening

Steel designation Hardness, HRC

C30 45–50

C 35 Mn 75 51–57

C 45 55–61

C 55 57–62

37 Mn 2 53–59

47 Mn 2 54–60

35 Mn 2 Mo 28 53–59

40 Cr 1 54–60

50 Cr 1 57–62

50 Cr 1 V 23 57–62

40 Cr 1 Mo 28 54–60

40 Ni 3 54–60

35 Ni 1 Cr 60 54–60

40 Ni 2 Cr1 Mo 28 54–60