Comparative Hardness Scales for Steel Table

Engineering Materials

Comparison of Hardness Scales: The following table compares the various hardness scales. Assumptions are that the metal tested is homogeneous to a depth several times that of the indentation. To the extent that the metal being tested is not homogeneous, errors are introduced because different loads and different shapes of penetrators meet the resistance of metal of varying hardness, depending on the depth of indentation. Another source of error is introduced in comparing the hardness of different materials as measured on different hardness scales. This error arises from the fact that in any hardness test, metal that is severely cold-worked actually supports the penetrator, and different metals, different alloys, and different analyses of the same type of alloy have different cold-working properties.

Comparative Hardness Scales for Steel Table

Rockwell
C-Scal
eHardness
Number
Diamond
Pyramid
Hardness
Number
Vickers
Brinell Hardness Number
10-mm Ball, 3000-kgf Load
Rockwell
Hardness Number
Rockwell Superficial Hardness Number
Superficial Diamond Indenter
Shore
Scleroscope
Hardness Number
Standard Ball
Hultgren
Ball
Tungsten
Carbide
Ball
A-Scale
60-kgf
Load
Diamond Indenter
D-Scale
100-kgf
Load
Diamond Indenter
15-N
Scale
15-kgf Load
30-N
Scale 30kgf
Load
45-N Scale
45-kgf
Load
68
940
85.6
76.9
93.2
84.4
75.4
97
67
900
85.0
76.1
92.9
83.6
74.2
95
66
865
84.5
75.4
92.5
82.8
73.3
92
65
832
(739)
83.9
74.5
92.2
81.9
72.0
91
64
800
(722)
83.4
73.8
91.8
81.1
71.0
88
63
772
(705)
82.8
73.0
91.4
80.1
69.9
87
62
746
(688)
82.3
72.2
91.1
79.3
68.8
85
61
720
(670)
81.8
71.5
90.7
78.4
67.7
83
60
697
(613)
(654)
81.2
70.7
90.2
77.5
66.6
81
59
674
(599)
(634)
80.7
69.9
89.8
76.6
65.5
80
58
653
(587)
615
80.1
69.2
89.3
75.7
64.3
78
57
633
(575)
595
79.6
68.5
88.9
74.8
63.2
76
56
613
(561)
577
79.0
67.7
88.3
73.9
62.0
75
55
595
(546)
560
78.5
66.9
87.9
73.0
60.9
74
54
577
(534)
543
78.0
66.1
87.4
72.0
59.8
72
53
560
(519)
525
77.4
65.4
86.9
71.2
58.6
71
52
544
(500)
(508)
512
76.8
64.6
86.4
70.2
57.4
69
51
528
(487)
(494)
496
76.3
63.8
85.9
69.4
56.1
68
50
513
(475)
(481)
481
75.9
63.1
85.5
68.5
55.0
67
49
498
(464)
(469)
469
75.2
62.1
85.0
67.6
53.8
66
48
484
(451)
(455)
455
74.7
61.4
84.5
66.7
52.5
64
47
471
442
443
443
74.1
60.8
83.9
65.8
51.4
63
46
458
432
432
432
73.6
60.0
83.5
64.8
50.3
62
45
446
421
421
421
73.1
59.2
83.0
64.0
49.0
60
44
434
409
409
409
72.5
58.5
82.5
63.1
47.8
58
43
423
400
400
400
72.0
57.7
82.0
62.2
46.7
57
42
412
390
390
390
71.5
56.9
81.5
61.3
45.5
56
41
402
381
381
381
70.9
56.2
80.9
60.4
44.3
55
40
392
371
371
371
70.4
55.4
80.4
59.5
43.1
54
39
382
362
362
362
69.9
54.6
79.9
58.6
41.9
52
38
372
353
353
353
69.4
53.8
79.4
57.7
40.8
51
37
363
344
344
344
68.9
53.1
78.8
56.8
39.6
50
36
354
336
336
336
68.4
52.3
78.3
55.9
38.4
49
35
345
327
327
327
67.9
51.5
77.7
55.0
37.2
48
34
336
319
319
319
67.4
50.8
77.2
54.2
36.1
47
33
327
311
311
311
66.8
50.0
76.6
53.3
34.9
46
32
318
301
301
301
66.3
49.2
76.1
52.1
33.7
44
31
310
294
294
294
65.8
48.4
75.6
51.3
32.5
43
30
302
286
286
286
65.3
47.7
75.0
50.4
31.3
42
29
294
279
279
279
64.7
47.0
74.5
49.5
30.1
41
28
286
271
271
271
64.3
46.1
73.9
48.6
28.9
41
27
279
264
264
264
63.8
45.2
73.3
47.7
27.8
40
26
272
258
258
258
63.3
44.6
72.8
46.8
26.7
38
25
266
253
253
253
62.8
43.8
72.2
45.9
25.5
38
24
260
247
247
247
62.4
43.1
71.6
45.0
24.3
37
23
254
243
243
243
62.0
42.1
71.0
44.0
23.1
36
22
248
237
237
237
61.5
41.6
70.5
43.2
22.0
35
21
243
231
231
231
61.0
40.9
69.9
42.3
20.7
35
20
238
226
226
226
60.5
40.1
69.4
41.5
19.6
34
(18)
230
219
219
219
33
(16)
222
212
212
212
32
(14)
213
203
203
203
31
(12)
204
194
194
194
29
(10)
196
187
187
187
28
(8)
188
179
179
179
27
(6)
180
171
171
171
26
(4)
173
165
165
165
25
(2)
166
158
158
158
24
(0)
160
152
152
152
24

Related: