Technical library

Hardness Conversion

ASTM E140-97 standard hardness conversion tables. Table 1 covers Rockwell C scale steels; Table 2 covers Rockwell B scale steels.

ASTM E140-97 Table 1 — Rockwell C Scale

HRC	HRA	15 N	30 N	45 N	HV
68	85.6	93.2	84.4	75.4	940
67	85.0	92.9	83.6	74.2	900
66	84.5	92.5	82.8	73.3	865
65	83.9	92.2	81.9	72.0	832
64	83.4	91.8	81.1	71.0	800
63	82.8	91.4	80.1	69.9	772
62	82.3	91.1	79.3	68.8	746
61	81.8	90.7	78.4	67.7	720
60	81.2	90.2	77.5	66.6	697
59	80.7	89.8	76.6	65.5	674
58	80.1	89.3	75.7	64.3	653
57	79.6	88.9	74.8	63.2	633
56	79.0	88.3	73.9	62.0	613
55	78.5	87.9	73.0	60.9	595
54	78.0	87.4	72.0	59.3	577
53	77.4	86.9	71.2	58.6	560
52	76.8	86.4	70.2	57.4	544
51	76.3	85.9	69.4	56.1	528
50	75.9	85.5	68.5	55.0	513
49	75.2	85.0	67.6	53.8	498
48	74.4	84.5	66.7	52.5	484
47	74.1	83.9	65.8	51.4	471
46	73.6	83.5	64.8	50.3	458
45	73.1	83.0	64.0	49.0	446
44	72.5	82.5	63.1	47.8	434
43	72.0	82.0	62.0	46.7	423
42	71.5	81.5	61.3	45.5	412
41	70.9	80.9	60.4	44.3	402
40	70.4	80.4	59.5	43.1	392
39	69.9	79.9	58.6	41.9	382
38	69.4	79.4	57.7	40.8	372
37	68.8	78.8	56.8	39.6	363
36	68.4	78.3	55.9	38.4	354
35	67.9	77.7	55.0	37.2	345
34	67.4	77.2	54.2	36.1	336
33	66.8	76.6	53.3	34.9	327
32	66.3	76.1	52.1	33.7	318
31	65.8	75.6	51.3	32.5	310
30	65.3	75.0	50.4	31.3	302
29	64.6	74.5	49.5	30.1	294
28	64.3	73.9	48.6	28.9	286
27	63.8	73.3	47.7	27.8	279
26	63.3	72.8	46.8	26.7	272
25	62.8	72.2	45.9	25.5	266
24	62.4	71.6	45.0	24.3	260
23	62.0	71.0	44.0	23.1	254
22	61.5	70.5	43.2	22.0	248
21	61.0	69.9	42.3	20.7	243
20	60.5	69.4	41.5	19.6	238

ASTM E140-97 Table 2 — Rockwell B Scale

HRB	HB	HRA	15 T	30 T	45 T	HV
100	240	61.5	93.1	83.1	72.9	240
99	234	60.9	92.8	82.5	71.9	234
98	228	60.2	92.5	81.8	70.9	228
97	222	59.5	92.1	81.1	69.9	222
96	216	58.9	91.8	80.4	68.9	216
95	210	58.3	91.5	79.8	67.9	210
94	205	57.6	91.2	79.1	66.9	205
93	200	57.0	90.8	78.4	65.9	200
92	195	56.4	90.5	77.8	64.8	195
91	190	55.8	90.2	77.1	63.8	190
90	185	55.2	89.9	76.4	62.8	185
89	180	54.6	89.5	75.8	61.8	180
88	176	54.0	89.2	75.1	60.8	176
87	172	53.4	88.9	74.4	59.8	172
86	169	52.8	88.6	73.8	58.8	169
85	165	52.3	88.2	73.1	57.8	165
84	162	51.7	87.9	72.4	56.8	162
83	159	51.1	87.6	71.8	55.8	159
82	156	50.6	87.3	71.1	54.8	156
81	153	50.0	86.9	70.4	53.8	153
80	150	49.5	86.6	69.7	52.8	150
79	147	48.9	86.3	69.1	51.8	147
78	144	48.4	86.0	68.4	50.8	144
77	141	47.9	85.6	67.7	49.8	141
76	139	47.3	85.3	67.1	48.8	139
75	137	46.8	85.0	66.4	47.8	137
74	135	46.3	84.7	65.7	46.8	135
73	132	45.8	84.3	65.1	45.8	132
72	130	45.3	84.0	64.4	44.8	130
71	127	44.8	83.7	63.7	43.8	127
70	125	44.3	83.4	63.1	42.8	125
69	123	43.8	83.0	62.4	41.8	123
68	121	43.3	82.7	61.7	40.8	121
67	119	42.8	82.4	61.0	39.8	119
66	117	42.3	82.1	60.4	38.7	117
65	116	41.8	81.8	59.7	37.7	116
64	114	41.4	81.4	59.0	36.7	114
63	112	40.9	81.1	58.4	35.7	112
62	110	40.4	80.8	57.7	34.7	110
61	108	40.0	80.5	57.0	33.7	108
60	107	39.5	80.1	56.4	32.7	107

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