Conversion Table of Hardness

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Conversion Table of Hardness

Approximate conversion value for steel Rockwell C hardness*1

(HRC)*3 Rockwell
C scale hardness
(HV)
Vickers hardness
Brinell hardness
(HB) 10mm ball
load 3000kgf
Rockwell hardness*3 Rockwell superficial hardness; diamond conical indenter
(HS) Tensile strength*2
(approximate value)
MPa
(HRC)*3 Rockwell
C scale hardness
Standard ball
Tungsten carbide ball
(HRA)
A scale load 60kgf
diamond conical indenter
(HRB)
B scale load
100kgf
diameter 1.6mm
(1/16in) ball
(HRD)
D scale load
100kgf
diamond conical indenter
15-N
scale load 15kgf
30-N
scale load 30kgf
45-N
scale load 45kgf
Shore hardness
68
67
66
65
64
940
900
865
832
800
-
-
-
-
-
-
-
-
(739)
(722)
85.6
85.0
84.5
83.9
83.4
-
-
-
-
-
76.9
76.1
75.4
74.5
73.8
93.2
92.9
92.5
92.2
91.8
84.4
83.6
82.8
81.9
81.1
75.4
74.2
73.3
72.0
71.0
97
95
92
91
88
-
-
-
-
-
68
67
66
65
64
63
62
61
60
59
772
746
720
697
674
-
-
-
-
-
(705)
(688)
(670)
(654)
(634)
82.8
82.3
81.8
81.2
80.7
-
-
-
-
-
73.0
72.2
71.5
70.7
69.9
91.4
91.1
90.7
90.2
89.8
80.1
79.3
78.4
77.5
76.6
69.9
68.8
67.7
66.6
65.5
87
85
83
81
80
-
-
-
-
-
63
62
61
60
59
58
57
56
55
54
653
633
613
595
577
-
-
-
-
-
615
595
577
560
543
80.1
79.6
79.0
78.5
78.0
-
-
-
-
-
69.2
68.5
67.7
66.9
66.1
89.3
88.9
88.3
87.9
87.4
75.7
74.8
73.9
73.0
72.0
64.3
63.2
62.0
60.9
59.8
78
76
75
74
72
-
-
-
2075
2015
58
57
56
55
54
53
52
51
50
49
560
544
528
513
498
-
(500)
(487)
(475)
(464)
525
512
496
481
469
77.4
76.8
76.3
75.9
75.2
-
-
-
-
-
65.4
64.6
63.8
63.1
62.1
86.9
86.4
85.9
85.5
85.0
71.2
70.2
69.4
68.5
67.6
58.6
57.4
56.1
55.0
53.8
71
69
68
67
66
1950
1880
1820
1760
1695
53
52
51
50
49
48
47
46
45
44
484
471
458
446
434
451
442
432
421
409
455
443
432
421
409
74.7
74.1
73.6
73.1
72.5
-
-
-
-
-
61.4
60.8
60.0
59.2
58.5
84.5
83.9
83.5
83.0
82.5
66.7
65.8
64.8
64.0
63.1
52.5
51.4
50.3
49.0
47.8
64
63
62
60
58
1635
1580
1530
1480
1435
48
47
46
45
44
43
42
41
40
39
423
412
402
392
382
400
390
381
371
362
400
390
381
371
362
72.0
71.5
70.9
70.4
69.9
-
-
-
-
-
57.7
56.9
56.2
55.4
54.6
82.0
81.5
80.9
80.4
79.9
62.2
61.3
60.4
59.5
58.6
46.7
45.5
44.3
43.1
41.9
57
56
55
54
52
1385
1340
1295
1250
1215
43
42
41
40
39
38
37
36
35
34
372
363
354
345
336
353
344
336
327
319
353
344
336
327
319
69.4
68.9
68.4
67.9
67.4
-
-
(109.0)
(108.5)
(108.0)
53.8
53.1
52.3
51.5
50.8
79.4
78.8
78.3
77.7
77.2
57.7
56.8
55.9
55.0
54.2
40.8
39.6
38.4
37.2
36.1
51
50
49
48
47
1180
1160
1115
1080
1055
38
37
36
35
34
33
32
31
30
29
327
318
310
302
294
311
301
294
286
279
311
301
294
286
279
66.8
66.3
65.8
65.3
64.7
(107.5)
(107.0)
(106.0)
(105.5)
(104.5)
50.0
49.2
48.4
47.7
47.0
76.6
76.1
75.6
75.0
74.5
53.3
52.1
51.3
50.4
49.5
34.9
33.7
32.5
31.3
30.1
46
44
43
42
41
1025
1000
980
950
930
33
32
31
30
29
28
27
26
25
24
286
279
272
266
260
271
264
258
253
247
271
264
258
253
247
64.3
63.8
63.3
62.8
62.4
(104.0)
(103.0)
(102.5)
(101.5)
(101.0)
46.1
45.2
44.6
43.8
43.1
73.9
73.3
72.8
72.2
71.6
48.6
47.7
46.8
45.9
45.0
28.9
27.8
26.7
25.5
24.3
41
40
38
38
37
910
880
860
840
825
28
27
26
25
24
23
22
21
20
(18)
254
248
243
238
230
243
237
231
226
219
243
237
231
226
219
62.0
61.5
61.0
60.5
-
100.0
99.0
98.5
97.8
96.7
42.1
41.6
40.9
40.1
-
71.0
70.5
69.9
69.4
-
44.0
43.2
42.3
41.5
-
23.1
22.0
20.7
19.6
-
36
35
35
34
33
805
785
770
760
730
23
22
21
20
(18)
(16)
(14)
(12)
(10)
( 8)
222
213
204
196
188
212
203
194
187
179
212
203
194
187
179
-
-
-
-
-
95.5
93.9
92.3
90.7
89.5
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
32
31
29
28
27
705
675
650
620
600
(16)
(14)
(12)
(10)
( 8)
( 6)
( 4)
( 2)
( 0)
180
173
166
160
171
165
158
152
171
165
158
152
-
-
-
-
87.1
85.5
83.5
81.7
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
26
25
24
24
580
550
530
515
( 6)
( 4)
( 2)
( 0)

*1: Bold numbers are according to ASTM E 140 Table 1による(arranged jointly by SAE, ASM and ASTM).
*2: 1MPa=1N/mm2
*3: The value in parentheses in the table are for ranges rarely used and indicated for reference.



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