127
HARDNESSCONVERSIONCHART FOR
HIGHSPEEDSTEEL
HV30
HRC
HV30
HRC
736
741
746
752
757
763
769
775
780
786
792
798
804
810
817
823
829
836
842
849
59-3/4
60
60-1/4
60-1/4
60-1/2
61
61
61-1/4
61-1/2
61-3/4
62
62-1/4
62-1/2
62-3/4
63
63-1/4
63-1/2
63-3/4
64
64-1/4
856
862
869
876
883
890
897
905
912
919
927
934
942
950
958
966
974
982
990
999
64-1/2
63-3/4
65
65-1/4
65-1/2
66
66
66-1/2
67
67
67-1/4
67-1/2
68
68
68-1/2
68-1/2
69
69-1/2
69-1/2
70
Typical hardness
M2
823-876 HV30 - 63-65 HRC
M35 849-920 HV30 - 64-66 HRC
M42 897-966 HV30 - 66 - 68-1/2 HRC
Depending on the nature of the tool these hardnessesmay be varied,
particularly in the case of special tools where different hardnesses
may be specified.
Note:
Undue reliance should not be placed on a general conversion chart
unless it has been tested for a particular material. The above chart
applies specifically to High Speed Steel.
