Hardness Tester Conversion Chart

Rockwell C Hardness Range

Approximate Hardness Conversion Numbers for Non-Austenitic Steels (Rockwell C Hardness Range)

  Brinell Hardness Number Rockwell Superficial Rockwell Number
Rockwell C 150kgf (HRC) Vickers (HV) 10-mm Standard ball 3000kgf (HBS) 10-mm Carbide ball 3000kgf (HBW) Knoop 500-gf and Over (HK) A Scale 60 kgf (HRA) D Scale 100kgf (HRD) 15-N Scale 15-kgf (HR15N) 30-N Scale 30-kgf (HR30N) 45-N Scale 45-kgf (HR45N) Sclero scope Hardness
68
67
66
65
64
63
62
61
60
59
58
57
56
55
54
53
52
51
50
49
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
940
900
865
832
800
772
746
720
697
674
653
633
613
595
577
560
544
528
513
498
484
471
458
446
434
423
412
402
392
382
372
363
354
345
336
327
318
310
302
294
286
279
272
266
260
254
248
243
238
















(500)
(487)
(475)
(464)
451
442
432
421
409
400
390
381
371
362
353
344
336
327
319
311
301
294
286
279
271
264
258
253
247
243
237
231
226



(739)
(722)
(705)
(688)
(670)
(654)
634
615
595
577
560
543
525
512
496
481
469
455
443
432
421
409
400
390
381
371
362
353
344
336
327
319
311
301
294
286
279
271
264
258
253
247
243
237
231
226
920
895
870
846
822
799
776
754
732
710
690
670
650
630
612
594
576
558
542
526
510
495
480
466
452
438
426
414
402
391
380
370
360
351
342
334
326
318
311
304
297
290
284
278
272
266
261
256
251
85.6
85.0
84.5
83.9
83.4
82.8
82.3
81.8
81.2
80.7
80.1
79.6
79.0
78.5
78.0
77.4
76.8
76.3
75.9
75.2
74.7
74.1
73.6
73.1
72.5
72.0
71.5
70.9
70.4
69.9
69.4
68.9
68.4
67.9
67.4
66.8
66.3
65.8
65.3
64.8
64.3
63.8
63.3
62.8
62.4
62.0
61.5
61.0
60.5
76.9
76.1
75.4
74.5
73.8
73.0
72.2
71.5
70.7
69.9
69.2
68.5
67.7
66.9
66.1
65.4
64.6
63.8
63.1
62.1
61.4
60.8
60.0
59.2
58.5
57.7
56.9
56.2
55.4
54.6
53.8
53.1
52.3
51.5
50.8
50.0
49.2
48.4
47.7
47.0
46.1
45.2
44.6
43.8
43.1
42.1
41.6
40.9
40.1
93.2
92.9
92.5
92.2
91.8
91.4
91.1
90.7
90.2
89.8
89.3
88.9
88.3
87.9
87.4
86.9
86.4
85.9
85.5
85.0
84.5
83.9
83.5
83.0
82.5
82.0
81.5
80.9
80.4
79.9
79.4
78.8
78.3
77.7
77.2
76.6
76.1
75.6
75.0
74.5
73.9
73.3
72.8
72.2
71.6
71.0
70.5
69.9
69.4
84.4
83.6
82.8
81.9
81.1
80.1
79.3
78.4
77.5
76.6
75.7
74.8
73.9
73.0
72.0
71.2
70.2
69.4
68.5
67.6
66.7
65.8
64.8
64.0
63.1
62.2
61.3
60.4
59.5
58.6
57.7
56.8
55.9
55.0
54.2
53.3
52.1
51.3
50.4
49.5
48.6
47.7
46.8
45.9
45.0
44.0
43.2
42.3
41.5
75.4
74.2
73.3
72.0
71.0
69.9
68.8
67.7
66.6
65.5
64.3
63.2
62.0
60.9
59.8
58.6
57.4
56.1
55.0
53.8
52.5
51.4
50.3
49.0
47.8
46.7
45.5
44.3
43.1
41.9
40.8
39.6
38.4
37.2
36.1
34.9
33.7
32.5
31.3
30.1
28.9
27.8
26.7
25.5
24.3
23.1
22.0
20.7
19.6
97.3
95.0
92.7
90.6
88.5
86.5
84.5
82.6
80.8
79.0
77.3
75.6
74.0
72.4
70.9
69.4
67.9
66.5
65.1
63.7
62.4
61.1
59.8
58.5
57.3
56.1
54.9
53.7
52.6
51.5
50.4
49.3
48.2
47.1
46.1
45.1
44.1
43.1
42.2
41.3
40.4
39.5
38.7
37.8
37.0
36.3
35.5
34.8
34.2

Rockwell B Hardness Range

Approximate Hardness Conversion Numbers for Non-Austenitic Steels (Rockwell B Hardness Range)

  Rockwell Superficial Rockwell Number
Rockwell B 100kgf (HRB) Vickers (HV) 10-mm Standard ball 3000kgf (HBS) Knoop 500-gf and Over (HK) A Scale 60 kgf (HRA) F Scale 60kgf (HRF) 15-T Scale 15-kgf (HR15T) 30-T Scale 30-kgf (HR30T) 45-T Scale 45-kgf (HR45T)
100
99
98
97
96
95
94
93
92
91
90
89
88
87
86
85
84
83
82
81
80
79
78
77
76
75
74
73
72
71
70
69
68
67
66
65
64
63
62
61
60
59
58
57
56
55

























240
234
228
222
216
210
205
200
195
190
185
180
176
172
169
165
162
159
156
153
150
147
144
141
139
137
135
132
130
127
125
123
121
119
117
116
114
112
110
108
107
106
104
103
101
100

























240
234
228
222
216
210
205
200
195
190
185
180
176
172
169
165
162
159
156
153
150
147
144
141
139
137
135
132
130
127
125
123
121
119
117
116
114
112
110
108
107
106
104
103
101
100

























251
246
241
236
231
226
221
216
211
206
201
196
192
188
184
180
176
173
170
167
164
161
158
155
152
150
147
145
143
141
139
137
135
131
129
127
125
124
122
120
118
117
115
114
112
111
110
109
108
107
106
105
104
103
102
101
100
99
98
97
96
95
94
93
92
91
90
89
88
87

61.5
60.9
60.2
59.5
58.9
58.3
57.6
57.0
56.4
55.8
55.2
54.6
54.0
53.4
52.8
52.3
51.7
51.1
50.6
50.0
49.5
48.9
48.4
47.9
47.3
46.8
46.3
45.8
45.3
44.8
44.3
43.8
43.3
42.8
42.3
41.8
40.9
40.4
40.0
39.5
39.0
38.6
38.1
37.7
37.2
36.8
36.3
35.9
35.5
35.0
34.6
34.1
33.7
33.3
32.9
32.4
32.0
31.6
31.2
30.7
30.3
29.9
29.5
29.1
28.7
28.2
27.8
27.4
27.0
26.6


























99.6
99.1
98.51
98.0
97.4
96.8
96.2
95.6
95.1
94.5
93.9
93.4
92.8
92.2
91.7
91.1
90.5
90.0
89.4
88.8
88.2
87.7
87.1
86.5
86.0
85.4
84.8
84.3
83.7
83.1
82.6
82.0
81.4
80.8
80.3
79.7
79.1
78.6
78.0
77.4
76.9
76.3
75.7
75.2
74.6
74.0
93.1
92.8
92.5
92.1
91.8
91.5
91.2
90.8
90.5
90.2
89.9
89.5
89.2
88.9
88.6
88.2
87.9
87.6
87.3
86.9
86.6
86.3
86.0
85.6
85.3
85.0
84.7
84.3
84.0
83.7
83.4
83.0
82.7
82.4
82.1
81.8
81.4
81.1
80.8
80.5
80.1
79.8
79.5
79.2
78.8
78.5
78.2
77.9
77.5
77.2
76.98
76.6
76.2
75.9
75.6
75.3
74.9
74.6
74.3
74.0
73.6
73.3
73.0
72.7
72.3
72.0
71.7
71.4
71.0
70.7
70.4
83.1
82.5
81.8
81.1
80.4
79.8
79.1
78.4
77.8
77.1
76.4
75.8
75.1
74.4
73.8
73.1
72.4
71.8
71.1
70.4
69.7
69.1
68.4
67.7
67.1
66.4
65.7
65.1
64.4
63.7
63.1
62.4
61.7
61.0
60.4
59.7
59.0
58.4
57.7
57.0
56.4
55.7
55.0
54.4
53.7
53.0
52.4
51.7
51.0
50.3
49.7
49.0
48.3
47.7
47.0
46.3
45.7
45.0
44.3
43.7
43.0
42.3
41.6
41.0
40.3
39.6
39.0
38.3
37.6
37.0
36.3
72.9
71.9
70.9
69.9
68.9
67.9
66.9
65.9
64.8
63.8
62.8
61.8
60.8
59.8
58.8
57.8
56.8
55.8
54.8
53.8
52.8
51.8
50.8
49.8
48.8
47.8
46.8
45.8
44.8
43.8
42.8
41.8
40.8
39.8
38.7
37.7
36.7
35.7
34.7
33.7
32.7
31.7
30.7
29.7
28.7
27.7
26.7
25.7
24.7
23.7
22.7
21.7
20.7
19.7
18.7
17.7
16.7
15.7
14.7
13.6
12.6
11.6
10.6
9.6
8.6
7.6
6.6
5.6
4.6
3.6
2.6

Leeb (type D) Hardness Range

Approximate Leeb (Type D) Hardness Conversion for Non-Austenitic Steels (Rockwell C Hardness Range)

Leeb Hardness, Type D Impact Device (HLD) Rockwell C Hardness 150kgf (HRC) Vickers Hardness (HV 10) Brinell Hardness 10mm Steel Ball 3000kgf (HBS)
828
819
809
800
791
782
773
764
755
746
737
729
720
712
703
695
687
679
671
663
655
647
640
632
625
618
611
603
596
590
583
576
570
563
557
551
545
539
533
527
521
516
510
62
61
60
59
58
57
56
55
54
53
52
51
50
49
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
762
737
711
688
667
645
625
605
586
568
550
534
517
503
487
473
460
447
434
422
410
398
388
377
368
358
349
339
330
323
314
306
299
291
284
277
271
264
258
251
245
240
234
(721)
(699)
(675)
(654)
634
614
595
577
559
542
526
511
496
482
467
455
442
430
418
407
395
385
375
365
356
347
338
328
320
313
305
297
291
283
276
270
264
258
252
246
240
235
229

Weight - Load - Indentor Chart

Scale Symbol Indentor Type Preliminary Force N (kgf) Total Force N(kgf) Typical Applications
A Spheroconical Diamond 98.07 (10) 588.4 (60) Cemented carbides, thin steel, and shallow case hardened steel
B 1/16” Carbide Ball 98.07 (10) 980.7 (100) Copper alloys, soft steels, aluminum alloys, malleable iron, etc.
C Spheroconical Diamond 98.07 (10) 1471 (150) Steel, hard cast irons, pearlitic malleable iron, titanium, deep case hardened steel, other harder than HRB 100
D Spheroconical Diamond 98.07 (10) 980.7 (100) Thin steel and medium case hardened steel, and pearlitic malleable iron
E 1/8” Carbide Ball 98.07 (10) 980.7 (100) Cast Iron, Aluminum and magnesium alloys, and bearing metals
F 1/16” Carbide Ball 98.07 (10) 588.4 (60) Annealed copper alloys and thin soft sheet metals
G 1/16” Carbide Ball 98.07 (10) 1471 (150) Malleable irons, copper-nickel-zinc and cupro-nickel alloys
H 1/8” Carbide Ball 98.07 (10) 588.4 (60) Aluminum, zinc and lead
K 1/8” Carbide Ball 98.07 (10) 1471 (150) Bearing Metals and other very soft or thin materials. Use smallest ball and heaviest load that doesn’t give anvil effect
L ¼” Carbide Ball 98.07 (10) 588.4 (60)
M ¼” Carbide Ball 98.07 (10) 980.7 (100)
P ¼” Carbide Ball 98.07 (10) 1471 (150)
R ½” Carbide Ball 98.07 (10) 588.4 (60)
S ½” Carbide Ball 98.07 (10) 980.7 (100)
V ½” Carbide Ball 98.07 (10) 1471 (150)
15N Spheroconical Diamond 29.42 (3) 147.1 (15) Similar to A, C and D scales but for thinner gage material.
30N Spheroconical Diamond 29.42 (3) 294.2 (30)
45N Spheroconical Diamond 29.42 (3) 441.3 (45)
15T 1/16” Carbide Ball 29.42 (3) 147.1 (15) Similar to B, F and G scales but for thinner gage material.
30T 1/16” Carbide Ball 29.42 (3) 294.2 (30)
45T 1/16” Carbide Ball 29.42 (3) 441.3 (45)
15W 1/8” Carbide Ball 29.42 (3) 147.1 (15) Very Soft Material
30W 1/8” Carbide Ball 29.42 (3) 294.2 (30)
45W 1/8” Carbide Ball 29.42 (3) 441.3 (45)
15X 1/4” Carbide Ball 29.42 (3) 147.1 (15)
30X 1/4” Carbide Ball 29.42 (3) 294.2 (30)
45X 1/4” Carbide Ball 29.42 (3) 441.3 (45)
15Y 1/2” Carbide Ball 29.42 (3) 147.1 (15)
30Y 1/2” Carbide Ball 29.42 (3) 294.2 (30)
45Y 1/2” Carbide Ball 29.42 (3) 441.3 (45)

Round Correction Factors

Corrections to be added to test results in the following scales for various diameter parts.

Corrections to be added to Rockwell C, A and D values

Diameter of Convex Cylindrical Surfaces

Hardness Reading ¼” 6.4mm 3/8” 10mm ½” 13mm 5/8” 16mm ¾” 19mm 7/8” 22mm 1” 25mm 1-1/4” 32mm 1-1/2” 38mm
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
6.0
5.5
5.0
4.0
3.5
3.0
2.5
2.0
1.5
1.5
1.0
1.0
0.5
0.5
0.5
4.5
4.0
3.5
3.0
2.5
2.0
2.0
1.5
1.0
1.0
1.0
0.5
0.5
0.5
0
3.5
3.0
2.5
2.0
2.0
1.5
1.5
1.0
1.0
1.0
0.5
0.5
0.5
0.5
0
2.5
2.5
2.0
1.5
1.5
1.0
1.0
1.0
0.5
0.5
0.5
0.5
0.5
0
0
2.0
2.0
1.5
1.5
1.0
1.0
1.0
0.5
0.5
0.5
0.5
0.5
0.5
0
0
1.5
1.5
1.5
1.0
1.0
1.0
0.5
0.5
0.5
0.5
0.5
0.5
0
0
0
1.5
1.0
1.0
1.0
1.0
0.5
0.5
0.5
0.5
0.5
0.5
0
0
0
0
1.0
1.0
1.0
0.5
0.5
0.5
0.5
0.5
0
0
0
0
0
0
0
1.0
1.0
0.5
0.5
0.5
0.5
0.5
0
0
0
0
0
0
0
0

Corrections to be added to Rockwell B, F and G values

Diameter of Convex Cylindrical Surfaces

Hardness Reading ¼” 6.4mm 3/8” 10mm ½” 13mm 5/8” 16mm ¾” 19mm 7/8” 22mm 1” 25mm
0
10
20
30
40
50
60
70
80
90
100
12.5
12.0
11.0
10.0
9.0
8.0
7.0
6.0
5.0
4.0
3.5
8.5
8.0
7.5
6.5
6.0
5.5
5.0
4.0
3.5
3.0
2.5
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
5.5
5.0
4.5
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.5
4.5
4.0
4.0
3.5
3.0
3.0
2.5
2.0
1.5
1.5
1.0
3.5
3.5
3.5
3.0
2.5
2.5
2.0
2.0
1.5
1.5
1.0
3.0
3.0
3.0
2.5
2.5
2.0
2.0
1.5
1.5
1.0
0.5

Minimum Thickness Requirements

Minimum allowable thickness for a corresponding hardness in the respective scales

Minimum Thickness Inch Minimum Thickness mm Rockwell C Rockwell A Rockwell B Superficial 15N Superficial 30N Superficial 45N Superficial 15T Superficial 30T Superficial 45T
0.006
0.008
0.010
0.012
0.014
0.016
0.018
0.020
0.022
0.024
0.026
0.028
0.030
0.032
0.034
0.036
0.038
0.040
0.15
0.20
0.25
0.30
0.36
0.41
0.46
0.51
0.56
0.61
0.66
0.71
0.76
0.81
0.86
0.91
0.96
1.02








69
67
65
62
57
52
45
37
28
20





86
84
82
79
76
71
67
60














94
87
80
71
62
52
40
28


92
90
88
83
76
68














82
78.5
74
66
57
47












77
74
72
68
63
58
51
37
20








91
86
81
75
68















80
72
64
55
45
34













71
62
53
43
31
18
4






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