M42 Steel Grade Equivalent Chart Standard ASTM A600-92a EN ISO 4957-1999 JIS G4403: 2006 ISO 4957-1999 Grades M42(t11342) HS 2-9-1-8 SKH59 HS 2-9-1-8 Delivery condition:In annealing (269HB), or after heat treatment (65.5-68.5HRC). Quality control 100% UT (Ultrasonic Testing), UT Standard is SEP 1921-84 C/c. M42 Steel Chemical Composition Stand C (%) Mn(%) P(%) S (%) Si (%) Cr (%) V(%) W(%) Mo(%) Co(%) ASTM A600-92a 1.05-1.15 0.15-0.40 0.03 0.03 0.15-0.65 3.50-4.25 0.95-1.35 1.15-1.85 9.00-10.00 7.75-8.75 EN ISO 4957-1999 1.05-1.15 0.40 0.030 0.030 0.70 3.50-4.50 0.90-1.30 1.20-1.90 9.00-10.00 7.50-8.50 JIS G4403: 2006 1.05-1.15 0.40 0.030 0.030 0.70 3.50-4.50 0.90-1.30 1.20-1.90 9.00-10.00 7.50-8.50 ISO 4957-1999 1.05-1.15 0.40 0.030 0.030 0.70 3.50-4.50 0.90-1.30 1.20-1.90 9.00-10.00 7.50-8.50 M42 Steel Physical Properties Physical properties Metric Imperial Density 7.81 g/cm 1.3247 Steel Mechanical Properties Mechanical properties Metric Imperial Hardness, Rockwell C(oil quenched from 1204 C, 5 minutes) 64.3 64.3 Hardness, Rockwell C(oil quenched from 1177 C, 5 minutes) 65.5 65.5