Critical point of common steel
| Note | Critical point /℃ |
|||
| Ac 1 | Ac 3 or Ac c I | Air 1 | Air 3 | |
| 10 | 725 | 870 | 682 | 850 |
| 10Mn2A | 720 | 830 | 620 | 714 |
| 12CrNi3A | 695 | 800 | 659 | 726 |
| 100CrNi3A | 680 | – | – | – |
| 12Cr2Ni4A | 670 | 780 | 575 | 660 |
| 100Cr2Ni4A | 670 | – | – | – |
| 15 | 725 | 870 | 685 | 850 |
| 15 minutes | 735 | 863 | 685 | 840 |
| 15SiMn2MoVA | 722 | 848 | 491 | – |
| 15 cr | 735 | 870 | 720 | – |
| 15CrMnA | 750 | 848 | – | – |
| 15CrMnMoVA | 765 | 870 | – | – |
| 18Mn2CrMoB | 741 | 854 | – | – |
| 18Cr2Ni4WA | 655~695 | – | – | – |
| 20 | 735 | 855 | 680 | 835 |
| 20 minutes | 735 | 854 | 682 | 835 |
| 20Mn2 | 690 | 820 | (610) | (760) |
| 20Mn2B | 730 | 835 | 613 | 730 |
| 20MnVB | 720 | 840 | 635 | 770 |
| 20MnTiB | (720) | 843 | 625 | 795 |
| 20MnMoB | 738 | 850 | 693 | 750 |
| 20 cr | 766 | 838 | 702 | 799 |
| 20CrV | 768 | 840 | 704 | 782 |
| 20CrMnB | – | 890 | 622 | 749 |
| 20CrNi | 735 | 805 | 660 | 790 |
| 20CrNi3A | 710 | 790 | – | – |
| 20Cr2Ni4A | 705 | 770 | 575 | 660 |
| 22CrMnMo | 710 | 830 | 620 | 740 |
| 30 | 732 | 813 | 677 | 796 |
| 30Mn2 | 718 | 804 | 627 | 727 |
| 30 minutes | 734 | 812 | 675 | 796 |
| 30SiMnMoV | 740 | 845 | – | – |
| 30Si2Mn2MoWV | 739 | 798 | – | – |
| 30CrMnSi | 760 | 830 | 670 | 705 |
| 30CrMo | 757 | 807 | 693 | 763 |
| 30CrMnTi | 765 | 790 | 500 | 740 |
| 30CrMnSiNi2A | 750~760 | 805~830 | – | – |
| 30CrNi3 | 705 | 750 | – | – |
| 35SiMn | 750 | 830 | 645 | – |
| 35CrMoV | 755 | 835 | 600 | – |
| 35CrMo | 755 | 800 | 695 | 750 |
| 35CrMnSi | 760 | 830 | 670 | 705 |
| 38 cr | 740 | 780 | 693 | 730 |
| 38CrMoAl | 800 | 840 | 730 | – |
| 37CrNi3 | 710 | 770 | 640 | – |
| 38CrSi | 763 | 810 | 680 | 755 |
| 40 | 724 | 790 | 680 | 760 |
| 40 minutes | 726 | 790 | 689 | 768 |
| 40Mn2 | 713 | 766 | 627 | 704 |
| 40MnB | 730 | 780 | 650 | 700 |
| 40MnVB | 730 | 774 | 639 | 681 |
| 40cr | 743 | 782 | 693 | 730 |
| 40CrV | 755 | 790 | 700 | 745 |
| 40CrMnMo | 735 | 780 | 680 | – |
| 40CrSi | 755 | 850 | – | – |
| 40CrMnSiMoV | 780 | 830 | – | – |
| 40CrMnSiMoVR | 725 | 850 | 625 | 715 |
| 40Cr 5M02VSi | 853 | 915 | 720 | 830 |
| 40SiMnMoVR | 765 | 900 | 625 | 730 |
| 40CrNi | 731 | 769 | 660 | 702 |
| 40CrNiMo | 710 | 790 | – | – |
| 40CrMo | 730 | 780 | – | – |
| 45 | 724 | 780 | 682 | 751 |
| 45Mn2 | 715 | 770 | 640 | 720 |
| 45Mn2V | 725 | 770 | – | – |
| 45cr | 721 | 771 | 660 | 693 |
| 50 | 720 | 765 | 690 | 720 |
| 50 minutes | 720 | 760 | 660 | – |
| 50Mn2 | 710 | 760 | 596 | 680 |
| 50cr | 721 | 771 | 660 | 692 |
| 50CrV | 752 | 788 | 688 | 746 |
| 50CrMn | 750 | 775 | – | – |
| 55 | 727 | 774 | 690 | 755 |
| 55Si2Mn | 775 | 840 | – | – |
| 55Si2MnB | 764 | 794 | – | – |
| 55Si2MnVB | 765 | 803 | – | – |
| 60 | 727 | 766 | 690 | 743 |
| 60Mn | 727 | 765 | 689 | 741 |
| 60Si2Mn | 755 | 810 | 700 | 770 |
| 65 | 727 | 752 | 696 | 730 |
| 65 minutes | 726 | 765 | 689 | 741 |
| 70 | 730 | 743 | 693 | 727 |
| 85 | 723 | 737 | – | 695 |
| T7 | 730 | 770 | 700 | – |
| T8 | 730 | – | 700 | – |
| T10 | 730 | 800 | 700 | – |
| T11 | 730 | 810 | 700 | – |
| T12 | 730 | 820 | 700 | – |
| SiMn | 760 | 865 | 708 | – |
| 9SiCr | 770 | 870 | 730 | – |
| CrWMn | 750 | 940 | 710 | – |
| 3Cr2W8V | 820 | 1100 | 790 | – |
| 3Cr2W8 | 810 | 1100 | – | – |
| W18Cr4V | 820 | 1330 | 760 | – |
| W9Cr4V2 | 810 | – | 760 | – |
| 3Cr 3Mo 3VNb | 836~948 | – | 771~923 | – |
| Cr12V | 810 | – | 760 | – |
| Cr12MoV | 815 | – | – | – |
| Cr 12Mo | 810 | 1200 | 760 | – |
| 5C rMnMo | 710 | 760 | 650 | – |
| 5CrNiMo | 710 | 770 | 680 | – |
| GCr15 | 745 | 900 | 700 | – |
| GCr15SiMn | 770 | 872 | 708 | – |
| 1Ch13 | 730 | 850 | 700 | 820 |
| 2Ch13 | 820 | 950 | 780 | – |
| 3Ch13 | 780~850 | – | – | – |
| 4Ch13 | 790~850 | – | – | – |
| Cr17Ni2 | 810 | – | 710 | – |
| 9Cr18 | 830 | – | 810 | – |
| 4Cr9Si2 | 900 | 970 | 810 | 870 |
| 4Cr10Si2Mo | 850 | 950 | 700 | 845 |
| Mn13 | – | – | – | – |
Quenching Heating Temperature and Ms Point of Common Steel
| Note | Extinguishing Heating Temperature (℃) |
IN /℃ |
| 10 | 900~920(water)or no heat treatment | 450 |
| 10Mn2A | 850~857(water) | – |
| 12CrNi3A | 860 (oil) 780 ~ 810 (oil) | (420) |
| 100CrNi3A | 860 (oil) 780 ~ 810 (oil) | 150 |
| 12Cr2Ni4A | 860 (oil) 780 (oil) | 400 |
| 100Cr2Ni4A | 880 (oil) 780 (oil) | 125 |
| 15 | 890~920(water) | 450 |
| 15 minutes | 850~900(water) | 410 |
| 15SiMn2MoVA | 880 (oil) | 275 |
| 15 cr | 860 (oil) 780 ~ 810 (oil) | – |
| 15CrMnA | 840~870(oil)810~840(oil) | 400 |
| 15CrMnMoVA | 965~985(air or oil) | 372 |
| 18Mn2CrMoB | 920 (air or oil) | 320 |
| 18Cr2Ni4WA | 950 (air) 860 ~ 870 (oil) | 310 |
| 100Cr2Ni4WA | – | 75 |
| 20 | 900~950(water) | 425 |
| 20 minutes | 850~900(water) | (420) |
| 20Mn2 | 860~880(water)880~910(oil) | 370 |
| 20Mn2B | 860~880(oil) | – |
| 20MnVB | 860~880(oil) | 230 |
| 20MnTiB | 860~890(oil) | – |
| 20MnMoB | 850~890 (oil) | – |
| 20 cr | 860~880(oil) | (390) |
| 20CrV | 870~900(oil) | – |
| 20CrMnB | 860~880(water or oil) | – |
| 20CrNi | 840~880(water or oil) | (410) |
| 20CrNi3A | 820~-840(oil) | (340) |
| 20Cr2Ni4A | (330) | |
| 22CrMnMo | 830~850(oil) | – |
| 30 | 850~890(water or oil) | 380 |
| 30Mn2 | 820~840(water)830~850(oil) | 340 |
| 30 minutes | 850~900(oil) | 355 |
| 30SiMnMoV | 850~890(oil) | |
| 30Si2Mn2MoWV | 950 (oil) | 310 |
| 30CrMnSi | 870~890(oil) | 320 |
| 30CrMo | 850~880(water or oil) | 345 |
| 30CrMnTi | 870~890(oil) | – |
| 30CrMnSiNi2A | 890~900(oil) | 314 |
| 30CrNi3 | 830 (oil) | 305 |
| 35SiMn | 880~900(oil) | (330) |
| 35CrMoV | 900~920(water or oil) | – |
| 35CrMo | 820~840(water)830~850(oil) | 271 |
| 35CrMnSi | 850~870(oil) | – |
| 38 cr | 860 (oil) | 250 |
| 38CrMoAl | 930~950(oil) | (370) |
| 37CrNi3 | 820 (oil) | (280) |
| 38CrSi | 900~920(water or oil) | (330) |
| 40 | 830~880(water or oil) | (340) |
| 40 minutes | 820~860(water or oil) | – |
| 40Mn2 | 810~850(oil) | (340) |
| 40MnB | 820~860(oil) | – |
| 40MnVB | 830~870(oil) | – |
| 40cr | 830~860(oil) | (355) |
| 40CrV | 880 (oil) | 218 |
| 40CrMnMo | 840~860(oil) | – |
| 40CrSi | 900~920(water or oil) | (320) |
| 40CrMnSiMoV | 920 (oil) | 290 |
| 40CrMnSiMoVR | 930 (oil) | 270 |
| 40Cr 5M02VSi | 1000 (air) | 325 |
| 40SiMnMoVR | 930 (oil) | 300~305 |
| 40CrNi | 820~840 | 271 |
| 40CrNiMo | 850 (oil) | 320 |
| 40CrMo | 820~840(water) | 360 |
| 45 | 780~860(water or oil) | (345) |
| 45Mn2 | 810~840(oil) | 320 |
| 45Mn2V | 840-860 (water) | 310 |
| 45cr | 820 ~ -840 (oil) | (355) |
| 50 | 820~850 (water or oil) | (320) |
| 50 minutes | 780 ~ 840 (water or oil) | 320 |
| 50Mn2 | 810-840 (oil) | 325 |
| 50cr | 820 (oil) | 250 |
| 50CrV | 860 (oil) | (270) |
| 50CrMn | 840~860 (oil) | (250) |
| 55 | 790~830(water)820~850(oil) | (290) |
| 55Si2Mn | 850~880(water or oil) | (280) |
| 55Si2MnB | 870 (oil) | – |
| 55Si2MnVB | 880 (oil) | – |
| 60 | 780~830(water or oil) | 270 |
| 60Mn | 790 ~ 820 (160 ℃ oil or nitrate) | 270 |
| 60Si2Mn | 840~860(water or oil) | 305 |
| 65 | 780~830(water or oil) | 270 |
| 65 minutes | 790-820 (160℃ oil or nitrate) | 270 |
| 70 | 780~830(water or oil) | 230 |
| 85 | 780~820(water or oil) | 220 |
| T7 | 800~820(water) | 250~300 |
| T8 | 780~820(water) | 225~250 |
| T10 | 770~790(water) | 175~210 |
| T11 | 770~790(water) | 200 |
| T12 | 770~790(water) | – |
| SiMn | 780~840(water, oil or nitrate) | (250) |
| 9SiCr | 860~870(oil) | (170) |
| CrWMn | 800~830(oil) | (250) |
| 3Cr2W8V | 1050~1100(oil) | (340) |
| 3Cr2W8 | 1075~1130(oil) | 330 |
| W18Cr4V | 1280~1300(oil) | (220) |
| W9Cr4V2 | 1225~1240(oil) | (200) |
| 3Cr 3Mo 3VNb | 1060~1090(oil) | 385 |
| Cr12V | 1040~1080(oil) | 180 |
| Cr12MoV | 1040~10501120~1130(air or) | (<185) |
| Cr 12Mo | 950~1000(oil) | (225) |
| 5C rMnMo | 820~850(oil) | (220) |
| 5CrNiMo | 830~860(oil) | (220) |
| GCr15 | 820~850(oil) | (240) |
| GCr15SiMn | 820~840(oil) | – |
| 1Ch13 | 980~1050(oil) | (350) |
| 2Ch13 | 980~1050(oil) | 320 |
| 3Ch13 | 980~1050(oil) | (240) |
| 4Ch13 | 980~1050(oil) | 145~270 |
| Cr17Ni2 | 950~970(oil) | 357 |
| 9Cr18 | 1050~1075(oil) | – |
| 4Cr9Si2 | 1000~1050(oil) | – |
| 4Cr10Si2Mo | 1010~1050(oil or air) | – |
| Mn13 | 1050 (oil or water) | 200 |
Note: the data in brackets in the table requires further study because:
1. Different data provides different data for the same steel grade, but only one is selected in this table:
2. Data of the same type of steel is collected from different data.







