Hardness Conversion Table

Brinell Hardness Number for 3000-kg load and 10-mm standard ball	Rockwell Hardness Number for B Scale, 100-kg load and 1/16th-in.-diam. ball	Rockwell Hardness Number for C Scale, 150-kg load and Brale indenter	Approx. Tensile Strength (ksi)		Brinell Hardness Number for 3000-kg load and 10-mm standard ball	Rockwell Hardness Number for B Scale, 100-kg load and 1/16th-in.-diam. ball	Rockwell Hardness Number for C Scale, 150-kg load and Brale indenter	Approx. Tensile Strength (ksi)
		59.2	355		322	(108.0)	34.4	155
(630)		58.8	348		313		33.3	150
		58.3	342		303	(107.0)	32.2	146
(613)		57.8	336		294		31.0	142
(602)		57.3	328		284	(105.5)	29.8	138
		56.8	323		280		29.2	136
(583)		56.3	317		275	(104.5)	28.5	133
		55.7	310		270		27.8	131
(562)		55.2	303		265	(103.5)	27.1	129
		54.7	298		261		26.4	127
(544)		54.1	293		256	(102.0)	25.6	124
		53.6	288		252		24.8	122
(525)		53.0	283		247	(101.0)	24.0	120
(505)	(120)	52.3	276		243		23.1	117
(496)		51.7	270		238	99.5	22.2	115
(488)		51.1	265		233		21.3	113
(480)	(119)	50.5	260		228	98.1	20.3	111
(473)		49.8	254		219	96.7	(18.0)	106
(465)		49.1	247		209	95.0	(15.7)	101
(456)	(117)	48.4	241		200	93.4	(13.4)	97
(448)		47.7	235		190	91.5	(11.0)	92
441	(116)	46.9	228		181	89.5	(8.5)	88
433		46.1	223		171	87.1	(6.0)	84
425	(115)	45.3	217		162	85.0	(3.0)	79
415		44.5	212		152	81.7	(0.0)	75
405	(114)	43.6	205		143	78.7		71
397		42.7	199		133	75.0		66
388		41.8	193		124	71.2		62
379	(112)	40.8	187		114	66.7		57
369		39.8	181		105	62.3
360	(110.0)	38.8	175		95	56.2
350		37.7	170		90	52.0
341	(109.0)	36.6	164		86	48.0
331		35.5	159		81	41.0

For carbon and alloy steels in the annealed, normalized, and quenched-and-tempered conditions; less accurate for cold worked and for austenitic steels.  The values in parentheses are beyond normal range and are given for information only.