ASTM

standard

                       Chemical composition

   C

Si

Mn

Cr

Ni

Cu

              <=

1070

70/C68D2B/C70D2B/C72D2B

0.67-0.75

0.17-0.37

0.50-0.80

0.25

0.30

0.25

1075

75/C76D2/C78D2/C82D2B

0.72-0.80

0.17-0.37

0.50-0.80

0.25

0.30

0.25

1080

80/C76D2B/C80D2B

0.77-0.85

0.17-0.37

0.50-0.80

0.25

0.30

0.25

1085

85/C86D2B

0.82-0.90

0.17-0.37

0.50-0.80

0.25

0.30

0.25

Grade steel

Size of blank sample(mm)

Recommended treatment(°C)

Mechanical properties

Hardness of steel delivery status

HBS10/3000<=

normalizing

annealing

turning

σb (MPa)≥

σs(MPa)≥

 δ5 (%)≥

 ψ (%)≥

Aku2J

Not heat-treated steel

Annealed steel

1070/70/C68D2B/C70D2B/C72D2B

25

790

715

420

9

30

269

229

1075/75/C76D2/C78D2/C82D2B

sample

820

480

1080

880

7

30

285

241

1080/80/C76D2B/C80D2B

sample

820

480

1080

930

6

30

285

241

1085/85/C86D2B

sample

820

480

1130

980

6

30

302

255