Rolled Metal Products

Technical Information : Approximate Rockwell Hardness Conversion Chart

Approximate Rockwell Hardness Conversion Numbers (Austenitic sheet steel)
Rockwell Hardness Number		Rockwell Superficial Hardness Number
C Scale, 150-kgf Diamond Penetrator (HRC)	A Scale, 60-kgf Diamond Penetrator (HRA)	15-N Scale, 15 kgf Superficial Diamond Penetrator (HR 15-N)	30-N Scale, 30-kgf Superficial Diamond Penetrator (HR 30-N)	45-N Scale, 45-kgf Superficial Diamond Penetrator (HR 45-N)
48.00	74.40	84.10	66.20	52.10
47.00	73.90	83.60	65.30	50.90
46.00	73.40	83.10	64.50	49.80
45.00	72.90	82.60	63.60	48.70
44.00	72.40	82.10	62.70	47.50
43.00	71.90	81.60	61.80	46.40
42.00	71.40	81.00	61.00	45.20
41.00	70.90	80.50	60.10	44.10
40.00	70.40	80.00	59.20	43.00
39.00	69.90	79.50	58.40	41.80
38.00	69.30	79.00	57.50	40.70
37.00	68.80	78.50	56.60	39.60
36.00	68.30	78.00	55.70	38.40
35.00	67.80	77.50	54.90	37.30
34.00	67.30	77.00	54.00	36.10
33.00	66.80	76.50	53.10	35.00
32.00	66.30	75.90	52.30	33.90
31.00	65.80	75.40	51.40	32.70
30.00	65.30	74.90	50.50	31.60
29.00	64.80	74.40	49.60	30.40
28.00	64.30	73.90	48.80	29.30
27.00	63.80	73.40	47.90	28.20
26.00	63.30	72.90	47.00	27.00
25.00	62.80	72.40	46.20	25.90
24.00	62.30	71.90	45.30	24.80
23.00	61.80	71.30	44.40	23.60
22.00	61.30	70.80	43.50	22.50
21.00	60.80	70.30	42.70	21.30
20.00	60.30	69.80	41.80	20.20

Approximate Rockwell Hardness Conversion Numbers (Austenitic sheet steel)
Rockwell Hardness Number		Rockwell Superficial Hardness Number
B Scale, 100-kgf 1/16 in (1.588mm) ball (HRB)	A Scale, 60-kgf Diamond Penetrator (HRA)	15-T Scale, 15 kgf 1/16 in (1.588 mm) ball (HR 15-T)	30-T Scale, 30-kgf 1/16 in (1.588mm) ball (HR 30-T)	45-T Scale, 45-kgf 1/16 in (1.588mm) ball (HR 45-T)
100	61.5	91.5	80.4	70.2
99	60.9	91.2	79.7	69.2
98	60.3	90.8	79.0	68.2
97	59.7	90.4	78.3	67.2
96	59.1	90.1	77.7	66.1
95	58.5	89.7	77.0	65.1
94	58.0	89.3	76.3	64.1
93	57.4	88.9	75.6	62.1
92	56.8	88.6	74.9	62.1
91	56.2	88.2	74.2	61.1
90	55.6	87.8	73.5	60.1
89	55.0	87.5	72.8	59.0
88	54.5	87.1	72.1	58.0
87	53.9	86.7	71.4	57.0
86	53.3	86.4	70.7	56.0
85	52.7	86.0	70.0	55.0
84	52.1	85.6	69.3	54.0
83	51.5	85.2	68.6	52.9
82	50.9	84.9	67.9	51.9
81	50.4	84.5	67.2	50.9
80	49.8	84.1	66.5	49.9
79	49.2	83.8	65.8	48.9
78	48.6	83.4	65.1	47.9
77	48.0	83.0	64.4	46.8
76	47.4	82.6	63.7	45.8
75	46.9	82.3	63.0	44.8
74	46.3	81.9	62.4	43.8
73	45.7	81.5	61.7	42.6
72	45.1	81.2	61.0	41.8
71	44.5	80.8	60.3	40.7
70	43.9	80.4	59.6	39.7
69	43.3	80.1	58.9	38.7
68	42.8	79.7	58.2	37.7
67	42.2	79.3	57.5	36.7
66	41.6	78.9	56.8	35.7
65	41.0	78.6	56.1	34.7
64	40.4	78.2	55.4	33.6
63	39.8	77.8	54.7	32.6
62	39.3	77.5	54.0	31.6
61	38.7	77.1	53.3	30.6
60	38.1	76.7	52.6	29.6