126
APPROXIMATE HARDNESSAND TENSILE
STRENGTHCONVERSIONS
TENSILE STRENGTH
MPa or
N/mm²
HRB
HRC
HV
HB
Tons/
inch²
50
55
60
65
70
75
80
85
90
95
100
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
20
22
24
26
28
30
32
34
36
38
40
42
44
46
48
50
52
54
56
58
60
64
66
68
70
75
80
95
100
110
120
130
140
150
165
185
205
230
240
255
265
280
295
310
325
345
360
380
405
425
450
480
505
545
580
615
655
695
790
855
940
1075
1480
1865
90
100
105
110
120
130
140
160
175
195
220
230
240
250
265
280
290
310
325
345
365
385
405
430
455
480
—
—
—
—
—
—
—
—
—
—
—
21
23
25
27
29
31
34
37
40
45
50
53
56
59
62
65
68
72
75
78
83
88
92
96
102
108
112
117
122
130
135
150
163
179
197
—
—
320
350
390
420
150
180
520
570
620
690
770
820
860
910
960
1000
1050
1110
1150
1200
1280
1360
1420
1480
1540
1670
1720
1800
1890
2000
2100
2320
2510
2770
3030
—
—
HRB = Hardness Rockwell B
HRC = Hardness Rockwell C
HV = Hardness Vickers. Also DPN, VPN, DPH, VPH
HB = Hardness Brinell. Also BHN
Note:
These values should be treated as approximate only and are suitable
for calculating speeds and feeds or for general information purposes.
Do not use for treated high speed steel.
