Normalizing, Annealing, Hardening & Tempering of Tool Steels Complete reference for heat-treating temperatures of all major tool steel grades, with both °C and °F values. The quench and temper schedule is also published as a standalone table in the hardening and tempering temperature chart , and the overall process sequence is covered in the tool steel heat treatment guide .
O = Oil quench · A = Air cool · S = Salt bath quench · W = Water quench · B = Brine quench
Normalizing & Annealing Type Normalizing (a) Annealing °C Annealing °F Cooling max °C/h Cooling max °F/h Hardness, HB M1 , M10Do not normalize 815-870 1500-1600 22 40 207-235 M2 Do not normalize 870-900 1600-1650 22 40 212-241 M3, M4 Do not normalize 870-900 1600-1650 22 40 223-255 M7 Do not normalize 815-870 1500-1600 22 40 217-255 M30, M33, M34, M35 , M36, M41, M42 , M46, M47 Do not normalize 870-900 1600-1650 22 40 235-269 M43 Do not normalize 870-900 1600-1650 22 40 248-269 M44 Do not normalize 870-900 1600-1650 22 40 248-293 M48 Do not normalize 870-900 1600-1650 22 40 285-311 M62 Do not normalize 870-900 1600-1650 22 40 262-285
Tungsten High-Speed Steels Type Normalizing (a) Annealing °C Annealing °F Cooling max °C/h Cooling max °F/h Hardness, HB T1 Do not normalize 870-900 1600-1650 22 40 217-255 T2 Do not normalize 870-900 1600-1650 22 40 223-255 T4 Do not normalize 870-900 1600-1650 22 40 229-269 T5 Do not normalize 870-900 1600-1650 22 40 235-277 T6 Do not normalize 870-900 1600-1650 22 40 248-293 T8 Do not normalize 870-900 1600-1650 22 40 229-255 T15 Do not normalize 870-900 1600-1650 22 40 241-277
Intermediate High-Speed Steels Type Normalizing (a) Annealing °C Annealing °F Cooling max °C/h Cooling max °F/h Hardness, HB M50 Do not normalize 830-845 1525-1550 22 40 197-235 M52 Do not normalize 830-845 1525-1550 22 40 197-235
Type Normalizing (a) Annealing °C Annealing °F Cooling max °C/h Cooling max °F/h Hardness, HB H10 , H11 , H12, H13 Do not normalize 845-900 1550-1650 22 40 192-229 H14 Do not normalize 870-900 1600-1650 22 40 207-235 H19 Do not normalize 870-900 1600-1650 22 40 207-241
Tungsten Hot-Work Steels Type Normalizing (a) Annealing °C Annealing °F Cooling max °C/h Cooling max °F/h Hardness, HB H21 , H22, H25Do not normalize 870-900 1600-1650 22 40 207-235 H23 Do not normalize 870-900 1600-1650 22 40 212-255 H24, H26 Do not normalize 870-900 1600-1650 22 40 217-241
Molybdenum Hot-Work Steels Type Normalizing (a) Annealing °C Annealing °F Cooling max °C/h Cooling max °F/h Hardness, HB H41, H43 Do not normalize 815-870 1500-1600 22 40 207-235 H42 Do not normalize 845-900 1550-1650 22 40 207-235
Type Normalizing (a) Annealing °C Annealing °F Cooling max °C/h Cooling max °F/h Hardness, HB D2 , D3 , D4Do not normalize 870-900 1600-1650 22 40 217-255 D5 Do not normalize 870-900 1600-1650 22 40 223-255 D7 Do not normalize 870-900 1600-1650 22 40 235-262
Type Normalizing (a) Annealing °C Annealing °F Cooling max °C/h Cooling max °F/h Hardness, HB A2 Do not normalize 845-870 1550-1600 22 40 201-229 A3 Do not normalize 845-870 1550-1600 22 40 207-229 A4 Do not normalize 740-760 1360-1400 14 25 200-241 A6 Do not normalize 730-745 1350-1375 14 25 217-248 A7 Do not normalize 870-900 1600-1650 14 25 235-262 A8 Do not normalize 845-870 1550-1600 22 40 192-223 A9 Do not normalize 845-870 1550-1600 14 25 212-248 A10 790 / 1450 765-795 1410-1460 8 15 235-269
Type Normalizing (a) Annealing °C Annealing °F Cooling max °C/h Cooling max °F/h Hardness, HB O1 870 / 1600 760-790 1400-1450 22 40 183-212 O2 845 / 1550 770-845 1375-1425 22 40 183-212 O6 870 / 1600 765-790 1410-1450 11 20 183-217 O7 900 / 1650 790-815 1450-1500 22 40 192-217
Type Normalizing (a) Annealing °C Annealing °F Cooling max °C/h Cooling max °F/h Hardness, HB S1 Do not normalize 790-815 1450-1500 22 40 183-229 (c) S2 Do not normalize 760-790 1400-1450 22 40 192-217 S5 Do not normalize 775-800 1425-1475 14 25 192-229 S7 Do not normalize 815-845 1500-1550 14 25 187-223
Type Normalizing (a) Annealing °C Annealing °F Cooling max °C/h Cooling max °F/h Hardness, HB P2 Not required 730-815 1350-1500 22 40 103-123 P3 Not required 730-815 1350-1500 22 40 109-137 P4 Do not normalize 870-900 1600-1650 14 25 116-128 P5 Not required 845-870 1550-1600 22 40 105-116 P6 Not required 845 1550 8 15 183-217 P20 900 / 1650 760-790 1400-1450 22 40 149-179 P21 900 / 1650 Do not anneal Do not anneal — — —
Low-Alloy Special-Purpose Steels Type Normalizing (a) Annealing °C Annealing °F Cooling max °C/h Cooling max °F/h Hardness, HB L2 871-900 / 1600-1650 760-790 1400-1450 22 40 163-197 L3 900 / 1650 790-815 1450-1500 22 40 174-201 L6 870 / 1600 760-790 1400-1450 22 40 183-212
Carbon-Tungsten Special-Purpose Steels Type Normalizing (a) Annealing °C Annealing °F Cooling max °C/h Cooling max °F/h Hardness, HB F1 900 / 1650 760-800 1400-1475 22 40 183-207 F2 900 / 1650 790-815 1450-1500 22 40 207-235
Water-Hardening Steels Type Normalizing (a) Annealing °C Annealing °F Cooling max °C/h Cooling max °F/h Hardness, HB W1, W2 790-925 (d) 740-790 (e) 1360-1450 (e) 22 40 156-201 W5 870-925 / 1600-1700 760-790 1400-1450 22 40 163-201
Notes & References (a) Time held at temperature varies from 15 min for small sections to 1 h for large sizes. Cooling is done in still air. Normalizing should not be confused with low-temperature annealing . (b) The upper limit of ranges should be used for large sections, and the lower limit for smaller sections. Time held at temperature varies from 1 h for light sections to 4 h for heavy sections and large furnace charges of high-alloy steel. (c) For 0.25 Si type, 183 to 207 HB; for 1.00 Si type, 207 to 229 HB. (d) Temperature varies with carbon content: 0.60–0.75 C, 815 °C (1500 °F); 0.75–0.90 C, 790 °C (1450 °F); 0.90–1.10 C, 870 °C (1600 °F); 1.10–1.40 C, 870–925 °C (1600–1700 °F). (e) Temperature varies with carbon content: 0.60–0.90 C, 740–790 °C (1360–1450 °F); 0.90–1.40 C, 760–790 °C (1400–1450 °F). Hardening & Tempering Molybdenum High-Speed Steels Type Rate of heating Preheat °C Preheat °F Hardening °C Hardening °F Time, min Quench (a) Tempering °C Tempering °F M1, M7, M10 Rapidly from preheat 730-845 1350-1550 1175-1220 (b) 2150-2225 (b) 2-5 O, A, or S 540-595 (c) 1000-1100 (c) M2 Rapidly from preheat 730-845 1350-1550 1190-1230 (b) 2175-2250 (b) 2-5 O, A, or S 540-595 (c) 1000-1100 (c) M3, M4, M30, M33, M34, M35 Rapidly from preheat 730-845 1350-1550 1205-1230 (b) 2200-2250 (b) 2-5 O, A, or S 540-595 (c) 1000-1100 (c) M36 Rapidly from preheat 730-845 1350-1550 1220-1245 (b) 2225-2275 (b) 2-5 O, A, or S 540-595 (c) 1000-1100 (c) M41 Rapidly from preheat 730-845 1350-1550 1190-1215 (b) 2175-2220 (b) 2-5 O, A, or S 540-595 (d) 1000-1100 (d) M42 Rapidly from preheat 730-845 1350-1550 1190-1210 (b) 2175-2210 (b) 2-5 O, A, or S 510-595 (d) 950-1100 (d) M43 Rapidly from preheat 730-845 1350-1550 1190-1215 (b) 2175-2220 (b) 2-5 O, A, or S 510-595 (d) 950-1100 (d) M44 Rapidly from preheat 730-845 1350-1550 1200-1225 (b) 2190-2240 (b) 2-5 O, A, or S 540-625 (d) 1000-1160 (d) M46 Rapidly from preheat 730-845 1350-1550 1190-1220 (b) 2175-2225 (b) 2-5 O, A, or S 525-565 (d) 975-1050 (d) M47 Rapidly from preheat 730-845 1350-1550 1175-1200 (b) 2150-2200 (b) 2-5 O, A, or S 525-595 (d) 975-1100 (d) M48 Rapidly from preheat 730-845 1350-1550 1175-1200 (b) 2150-2200 (b) 2-5 O, A, or S 540-595 (d) 1000-1100 (d) M62 Rapidly from preheat 730-845 1350-1550 1175-1200 (b) 2150-2200 (b) 2-5 O, A, or S 540-595 (d) 1000-1100 (d)
Tungsten High-Speed Steels Type Rate of heating Preheat °C Preheat °F Hardening °C Hardening °F Time, min Quench (a) Tempering °C Tempering °F T1, T2, T4, T8 Rapidly from preheat 815-870 1500-1600 1260-1300 (b) 2300-2375 (b) 2-5 O, A, or S 540-595 (c) 1000-1100 (c) T5, T6 Rapidly from preheat 815-870 1500-1600 1275-1300 (b) 2325-2375 (b) 2-5 O, A, or S 540-595 (c) 1000-1100 (c) T15 Rapidly from preheat 815-870 1500-1600 1205-1260 (b) 2200-2300 (b) 2-5 O, A, or S 540-650 (d) 1000-1200 (d)
Intermediate High-Speed Steels Type Rate of heating Preheat °C Preheat °F Hardening °C Hardening °F Time, min Quench (a) Tempering °C Tempering °F M50 Rapidly from preheat 730-845 1350-1550 1095-1120 2000-2050 2-5 O, A, or S 525-595 975-1100 M52 Rapidly from preheat 730-845 1350-1550 1120-1175 2050-2150 2-5 O, A, or S 525-595 975-1100
Chromium Hot-Work Steels Type Rate of heating Preheat °C Preheat °F Hardening °C Hardening °F Time, min Quench (a) Tempering °C Tempering °F H10 Moderately from preheat 815 1500 1010-1040 1850-1900 15-40 (e) A 540-650 1000-1200 H11 , H12Moderately from preheat 815 1500 995-1025 1825-1875 15-40 (e) A 540-650 1000-1200 H13 Moderately from preheat 815 1500 995-1040 1825-1900 15-40 (e) A 540-650 1000-1200 H14 Moderately from preheat 815 1500 1010-1065 1850-1950 15-40 (e) A 540-650 1000-1200 H19 Moderately from preheat 815 1500 1095-1205 2000-2200 2-5 A or O 540-705 1000-1300
Tungsten Hot-Work Steels Type Rate of heating Preheat °C Preheat °F Hardening °C Hardening °F Time, min Quench (a) Tempering °C Tempering °F H21, H22 Rapidly from preheat 815 1500 1095-1205 2000-2200 2-5 A or O 595-675 1100-1250 H23 Rapidly from preheat 845 1550 1205-1260 2200-2300 2-5 O 650-815 1200-1500 H24 Rapidly from preheat 815 1500 1095-1230 2000-2250 2-5 O 565-650 1050-1200 H25 Rapidly from preheat 815 1500 1150-1260 2100-2300 2-5 A or O 565-675 1050-1250 H26 Rapidly from preheat 870 1600 1175-1260 2150-2300 2-5 O, A or S 565-675 1050-1250
Molybdenum Hot-Work Steels Type Rate of heating Preheat °C Preheat °F Hardening °C Hardening °F Time, min Quench (a) Tempering °C Tempering °F H41, H43 Rapidly from preheat 730-845 1350-1550 1095-1190 2000-2175 2-5 O, A or S 565-650 1050-1200 H42 Rapidly from preheat 730-845 1350-1550 1120-1220 2050-2225 2-5 O, A or S 565-650 1050-1200
High-Carbon, High-Chromium Cold-Work Steels Type Rate of heating Preheat °C Preheat °F Hardening °C Hardening °F Time, min Quench (a) Tempering °C Tempering °F D1, D5 Very slowly 815 1500 980-1025 1800-1875 15-45 A 205-540 400-1000 D3 Very slowly 815 1500 925-980 1700-1800 15-45 O 205-540 400-1000 D4 Very slowly 815 1500 970-1010 1775-1850 15-45 A 205-540 400-1000 D7 Very slowly 815 1500 1010-1065 1850-1950 30-60 A 150-540 300-1000
Medium-Alloy, Air-Hardening Cold-Work Steels Type Rate of heating Preheat °C Preheat °F Hardening °C Hardening °F Time, min Quench (a) Tempering °C Tempering °F A2 Slowly 790 1450 925-980 1700-1800 20-45 A 175-540 350-1000 A3 Slowly 790 1450 955-980 1750-1800 25-60 A 175-540 350-1000 A4 Slowly 675 1250 815-870 1500-1600 20-45 A 175-425 350-800 A6 Slowly 650 1200 830-870 1525-1600 20-45 A 150-425 300-800 A7 Very slowly 815 1500 955-980 1750-1800 30-60 A 150-540 300-1000 A8 Slowly 790 1450 980-1010 1800-1850 20-45 A 175-595 350-1100 A9 Slowly 790 1450 980-1025 1800-1875 20-45 A 510-620 950-1150 A10 Slowly 650 1200 790-815 1450-1500 30-60 A 175-425 350-800
Oil-Hardening Cold-Work Steels Type Rate of heating Preheat °C Preheat °F Hardening °C Hardening °F Time, min Quench (a) Tempering °C Tempering °F O1 Slowly 650 1200 790-815 1450-1500 10-30 O 175-260 350-500 O2 Slowly 650 1200 760-800 1400-1475 5-20 O 175-260 350-500 O6 Slowly — — 790-815 1450-1500 10-30 O 175-315 350-600 O7 Slowly 650 1200 W: 790-830 / O: 845-885 W: 1450-1525 / O: 1550-1625 10-30 O or W 175-290 350-550
Shock-Resisting Steels Type Rate of heating Preheat °C Preheat °F Hardening °C Hardening °F Time, min Quench (a) Tempering °C Tempering °F S1 Slowly — — 900-955 1650-1750 15-45 O 205-650 400-1200 S2 Slowly 650 (f) 1200 (f) 845-900 1550-1650 5-20 B or W 175-425 350-800 S5 Slowly 760 1400 870-925 1600-1700 5-20 O 175-425 350-800 S7 Slowly 650-705 1200-1300 925-955 1700-1750 15-45 A or O 205-260 400-500
Mold Steels Type Rate of heating Preheat °C Preheat °F Hardening °C Hardening °F Time, min Quench (a) Tempering °C Tempering °F P2 — — — 900-925 (g) / 830-845 (h) 1650-1750 (g) / 1525-1550 (h) 15 O 175-260 350-500 P3 — — — 900-925 (g) / 800-830 (h) 1650-1700 (g) / 1475-1525 (h) 15 O 175-260 350-500 P4 — — — 970-995 (g) / 970-995 (h) 1775-1825 (g) / 1775-1825 (h) 15 A 175-480 350-900 P5 — — — 900-925 (g) / 845-870 (h) 1650-1700 (g) / 1550-1600 (h) 15 O or W 175-260 350-500 P6 — — — 900-925 (g) / 790-815 (h) 1650-1700 (g) / 1450-1500 (h) 15 A or O 175-230 350-450 P20 — — — 870-900 (h) / 815-870 1600-1650 (h) / 1500-1600 15 O 480-595 (i) 900-1100 (i) P21 (j) Slowly Do not preheat — 705-730 1300-1350 60-180 A or O 510-550 950-1025
Low-Alloy Special-Purpose Steels Type Rate of heating Preheat °C Preheat °F Hardening °C Hardening °F Time, min Quench (a) Tempering °C Tempering °F L2 Slowly — — W: 790-845 / O: 845-925 W: 1450-1550 / O: 1550-1700 10-30 O or W 175-540 350-1000 L3 Slowly — — W: 775-815 / O: 815-870 W: 1425-1500 / O: 1500-1600 10-30 O or W 175-315 350-600 L6 Slowly — — 790-845 1450-1550 10-30 O 175-540 350-1000
Carbon-Tungsten Special-Purpose Steels Type Rate of heating Preheat °C Preheat °F Hardening °C Hardening °F Time, min Quench (a) Tempering °C Tempering °F F1, F2 Slowly 650 1200 790-870 1450-1600 15 W or B 175-260 350-500
Water-Hardening Steels Type Rate of heating Preheat °C Preheat °F Hardening °C Hardening °F Time, min Quench (a) Tempering °C Tempering °F W1, W2, W3 Slowly 565-650 (k) 1050-1200 (k) 760-845 1400-1550 10-30 B or W 175-345 350-650
Notes & References (a) O, oil quench; A, air cool; S, salt bath quench; W, water quench; B, brine quench. (b) When the high-temperature heating is carried out in a salt bath, the range of temperatures should be about 14 °C (25 °F) lower than given here. (c) Double tempering recommended for not less than 1 h at temperature each time. (d) Triple tempering recommended for not less than 1 h at temperature each time. (e) Times apply to open furnace heat treatment. For pack hardening , a common rule is to heat 1.2 min per mm (30 min per in.) of cross section of the pack. (f) Preferable for large tools to minimize decarburization. (g) Carburizing temperature. (h) After carburizing. (i) Carburized per case hardness. (j) P21 is a precipitation-hardening steel having a thermal treatment that involves solution treating and aging rather than hardening and tempering. (k) Recommended for large tools and tools with intricate sections. Supply Scope & Technical Reference Note Aobo Steel supplies tool steel in an annealed condition and does not provide final heat-treatment services such as hardening, quenching, cryogenic treatment, or tempering.
The heat treatment parameters, hardness data, and process recommendations in this reference are provided as general technical support for our customers. Actual heat-treatment results may vary depending on furnace capacity, section size, tool geometry, material condition, quenching practice, and process control. Final heat-treatment procedures and validation should be performed by the customer’s heat-treatment facility in accordance with the specific tooling application and production requirements.
Related reference pages Tool steel properties chart · Hot hardness chart · Forging temperature guide · ASTM grain size chart · Heat color chart · Hardness conversion calculator · Tool steel material finder · Tool steel size change in heat treatment
Data source: ASM Handbook, Wrought Tool Steels (revised by Alan M. Bayer, Teledyne Vasco, and Lee R. Walton, Latrobe Steel Company). Tables 8 & 9. Data compiled from public references and industry standards.
