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DIN 1.2312

Pre-hardened tool steel with improved machinability

DIN 1.2312 is an alloyed pre-hardened tool steel for molds, derived from grade 1.2311 (40CrMnMo7), which is additionally alloyed with sulfur (S ≈ 0.08–0.12%) to improve machinability. The steel is supplied in a pre-hardened state (approx. 30–34 HRC), so it is ready for immediate use without the need for further heat treatment.
Due to its combination of good machinability, toughness and strength, it is widely used for plastic molds, die casting and mold structural parts.


Alternative designation : 40CrMnMoS8.6

Type : Pre-hardened tool steel for molds

Chemical composition (approximate) :
C: 0.35–0.45%
Mn: 1.40–1.60%
Cr: 1.80–2.10%
Mo: 0.15–0.25%
S: 0.08–0.12%

Heat treatment:

  • It is not overdone as standard – it is used in the delivered condition

  • To improve the surface:

  • Nitriding

  • PVD/CVD coating

  • Possible relief annealing: approx. 550–600 °C

Round bars, rolled, peeled, tempered to 950-1100 N/mm2

21

26

31

41

51

61

71

81

91

102

































Forged blocks, tempered to 950-1100 N/mm2


510

610

810

1010

1200







510

X

X

X

X

X

































Rolled sheets, tempered to 950-1100 N/mm2

10

16

21

26

31

36

41

46

51

56

61

71

76

81

91

95

100

111

120

130

141

150

160

170

180

190

200

210

230

250




















Features:

  • Supplied in pre-hardened condition (~30–32 HRC)

  • Excellent machinability thanks to the addition of sulfur

  • Good dimensional stability during machining

  • Suitable for polishing, but worse than 1.2311 or 1.2083

  • Not suitable for surface etching or optical shine

  • Can be nitrided or coated to increase surface hardness

Use:

  • Plastic injection molds with lower polishing requirements

  • Mold inserts, mold frames, support plates

  • Molds for large-scale products with an emphasis on rapid production

  • Machine and structural parts requiring strength and good machining

  • Use where easy production without heat treatment is required

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