Processing & Service Characteristics of Tool Steels Comparative ratings for decarburization resistance, hardening response, distortion, cracking resistance, hardness, machinability, toughness, wear resistance and softening resistance across all major tool steel grades.
Rated columns use the eight step scale: Lowest, Low, Low to medium, Medium, Medium to high, High, Very high, Highest. Higher is better for decarburization resistance, cracking resistance, machinability, toughness, wear resistance and softening resistance; for amount of distortion, a lower rating is better. Hardening response is listed as shallow, medium or deep, and hardness as an HRC range.
Molybdenum High-Speed Steels Type Resistance to decarburization Hardening response Amount of distortion (a) Resistance to cracking Approx. hardness, HRC (b) Machinability Toughness Resistance to wear Resistance to softening M1 Low Deep A or S, low; O, medium Medium 60-65 Medium Low Very high Very high M2 Medium Deep A or S, low; O, medium Medium 60-65 Medium Low Very high Very high M3 (class 1 and 2) Medium Deep A or S, low; O, medium Medium 61-66 Medium Low Very high Very high M4 Medium Deep A or S, low; O, medium Medium 61-66 Low to medium Low Very high Highest M7 Low Deep A or S, low; O, medium Medium 61-66 Medium Low Very high Very high M10 Low Deep A or S, low; O, medium Medium 60-65 Medium Low Very high Very high M30 Low Deep A or S, low; O, medium Medium 60-65 Medium Low Highest Very high M33 Low Deep A or S, low; O, medium Medium 60-65 Medium Low Highest Very high M34 Low Deep A or S, low; O, medium Medium 60-65 Medium Low Highest Very high M35 Low Deep A or S, low; O, medium Medium 60-65 Medium Low Highest Very high M36 Low Deep A or S, low; O, medium Medium 60-65 Medium Low Highest Very high M41 Low Deep A or S, low; O, medium Medium 65-70 Medium Low Highest Very high M42 Low Deep A or S, low; O, medium Medium 65-70 Medium Low Highest Very high M43 Low Deep A or S, low; O, medium Medium 65-70 Medium Low Highest Very high M44 Low Deep A or S, low; O, medium Medium 62-70 Medium Low Highest Very high M46 Low Deep A or S, low; O, medium Medium 67-69 Medium Low Highest Very high M47 Low Deep A or S, low; O, medium Medium 65-70 Medium Low Highest Very high M48 Low Deep A or S, low; O, medium Medium 65-70 Low Low Highest Highest M62 Low Deep A or S, low; O, medium Medium 62-68 Medium Low Highest Very high
Tungsten High-Speed Steels Type Resistance to decarburization Hardening response Amount of distortion (a) Resistance to cracking Approx. hardness, HRC (b) Machinability Toughness Resistance to wear Resistance to softening T1 High Deep A or S, low; O, medium High 60-65 Medium Low Very high Very high T2 High Deep A or S, low; O, medium High 61-66 Medium Low Very high Very high T4 Medium Deep A or S, low; O, medium Medium 62-66 Medium Low Highest Very high T5 Low Deep A or S, low; O, medium Medium 60-65 Medium Low Highest Very high T6 Low Deep A or S, low; O, medium Medium 60-65 Low to medium Low Highest Very high T8 Medium Deep A or S, low; O, medium Medium 60-65 Medium Low Highest Very high T15 Medium Deep A or S, low; O, medium Medium 63-68 Low to medium Low Highest Highest
Intermediate High-Speed Steels Type Resistance to decarburization Hardening response Amount of distortion (a) Resistance to cracking Approx. hardness, HRC (b) Machinability Toughness Resistance to wear Resistance to softening M50 Low Deep A or S, low; O, medium Medium 58-63 Medium Low High High M52 Low Deep A or S, low; O, medium Medium 58-64 Medium Low High High
Chromium Hot-Work Steels Type Resistance to decarburization Hardening response Amount of distortion (a) Resistance to cracking Approx. hardness, HRC (b) Machinability Toughness Resistance to wear Resistance to softening H10 Medium Deep Very low Highest 39-56 Medium to high High High Medium H11 Medium Deep Very low Highest 38-54 Medium to high Very high High Medium H12 Medium Deep Very low Highest 38-55 Medium to high Very high High Medium H13 Medium Deep Very low Highest 38-53 Medium to high Very high High Medium H14 Medium Deep Low Highest 40-47 Medium High High Medium H19 Medium Deep A, low; O, medium High 40-57 Medium High High Medium to high
Tungsten Hot-Work Steels Type Resistance to decarburization Hardening response Amount of distortion (a) Resistance to cracking Approx. hardness, HRC (b) Machinability Toughness Resistance to wear Resistance to softening H21 Medium Deep A, low; O, medium High 36-54 Medium High High Medium to high H22 Medium Deep A, low; O, medium High 39-52 Medium High High Medium to high H23 Medium Deep Medium High 34-47 Medium Medium Very high Medium to high H24 Medium Deep A, low; O, medium High 45-55 Medium Medium Very high High H25 Medium Deep A, low; O, medium High 35-44 Medium High Very high Medium H26 Medium Deep A or S, low; O, medium High 43-58 Medium Medium Very high High
Molybdenum Hot-Work Steels Type Resistance to decarburization Hardening response Amount of distortion (a) Resistance to cracking Approx. hardness, HRC (b) Machinability Toughness Resistance to wear Resistance to softening H42 Medium Deep A or S, low; O, medium Medium 50-60 Medium Medium Very high High
Air-Hardening, Medium-Alloy Cold-Work Steels Type Resistance to decarburization Hardening response Amount of distortion (a) Resistance to cracking Approx. hardness, HRC (b) Machinability Toughness Resistance to wear Resistance to softening A2 Medium Deep Lowest Highest 57-62 Medium Medium High High A3 Medium Deep Lowest Highest 57-65 Medium Medium High Very high A4 Medium to high Deep Lowest Highest 54-62 Low to medium Medium Medium Medium to high A6 Medium to high Deep Lowest Highest 54-60 Low to medium Medium Medium Medium to high A7 Medium Deep Lowest Highest 57-67 Low Low High Highest A8 Medium Deep Lowest Highest 50-60 Medium High High Medium to high A9 Medium Deep Lowest Highest 35-56 Medium High High Medium to high A10 Medium to high Deep Lowest Highest 55-62 Medium to high Medium Medium High
High-Carbon, High-Chromium Cold-Work Steels Type Resistance to decarburization Hardening response Amount of distortion (a) Resistance to cracking Approx. hardness, HRC (b) Machinability Toughness Resistance to wear Resistance to softening D2 Medium Deep Lowest Highest 54-61 Low Low High High to very high D3 Medium Deep Very low High 54-61 Low Low High Very high D4 Medium Deep Lowest Highest 54-61 Low Low High Very high D5 Medium Deep Lowest Highest 54-61 Low Low High High to very high D7 Medium Deep Lowest Highest 58-65 Low Low High Highest
Oil-Hardening Cold-Work Steels Type Resistance to decarburization Hardening response Amount of distortion (a) Resistance to cracking Approx. hardness, HRC (b) Machinability Toughness Resistance to wear Resistance to softening O1 High Medium Very low Very high 57-62 High Medium Low Medium O2 High Medium Very low Very high 57-62 High Medium Low Medium O6 High Medium Very low Very high 58-63 Highest Medium Low Medium O7 High Medium O, very low; W, high W, low; O, very high 58-64 High Medium Low Medium
Shock-Resisting Steels Type Resistance to decarburization Hardening response Amount of distortion (a) Resistance to cracking Approx. hardness, HRC (b) Machinability Toughness Resistance to wear Resistance to softening S1 Medium Medium Medium High 40-58 Medium Very high Medium Low to medium S2 Low Medium High Low 50-60 Medium to high Highest Low Low to medium S5 Low Medium Medium High 50-60 Medium to high Highest Low Low to medium S6 Low Medium Medium High 54-56 Medium Very high Low Low to medium S7 Medium Deep A, lowest; O, low O, high; A, highest 45-57 Medium Very high High Low to medium
Low-Alloy Special-Purpose Steels Type Resistance to decarburization Hardening response Amount of distortion (a) Resistance to cracking Approx. hardness, HRC (b) Machinability Toughness Resistance to wear Resistance to softening L2 High Medium O, medium; W, low O, medium; W, high 45-63 High Very high Low Low to medium L6 High Medium Low High 45-62 Medium Very high Low Medium
Low-Carbon Mold Steels Type Resistance to decarburization Hardening response Amount of distortion (a) Resistance to cracking Approx. hardness, HRC (b) Machinability Toughness Resistance to wear Resistance to softening P2 High Medium Low High 58-64 (c) Medium to high High Low Medium P3 High Medium Low High 58-64 (c) Medium High Low Medium P4 High High Very low High 58-64 (c) Low to medium High Medium High P5 High — O, low; W, high High 58-64 (c) Medium High Low Medium P6 High — A, very low; O, low High 58-61 (c) Medium High Low Medium P20 High Medium Low High 28-37 Medium to high High Low Low to medium P21 High Deep Lowest Highest 30-40 (d) Medium Medium Medium Medium
Water-Hardening Steels Type Resistance to decarburization Hardening response Amount of distortion (a) Resistance to cracking Approx. hardness, HRC (b) Machinability Toughness Resistance to wear Resistance to softening W1 Highest Shallow High Medium 50-64 Highest High (e) Low Low to medium W2 Highest Shallow High Medium 50-64 Highest High (e) Low Low to medium W5 Highest Shallow High Medium 50-64 Highest High (e) Low Low to medium
Related pages: tool steel supply for the grades, sizes and supply forms we deliver, DC53 for the cold-work grade we produce in house, and D6 with its heat treatment schedule for the high wear grade that Table 10 does not list.
Data source: ASM Handbook, Wrought Tool Steels (revised by Alan M. Bayer, Teledyne Vasco, and Lee R. Walton, Latrobe Steel Company). Table 10. Data compiled from public references and industry standards.
