Steel hardness Archives - Ecomolding.com

Steel hardness describes the properties of steels that resist deformation, indentation, penetration, and scratching. steel hardness is important because the inherent resistance of the surface to withstand friction or erosion by oil, steam, and water from injection molding process,there are several harness test method as below:

1.Brinell Hardness (HB)
Press a hardened steel ball of a certain size (usually 10mm in diameter) against the surface of the material with a certain load (usually 3,000kg) for a period of time. After the load is removed, the ratio of the load to the area of indentation is referred to as the Brinell hardness (HB), measured in kg/mm² (N/mm²).

2．Vickers Hardness (HV)
Use a diamond square cone presser to penetrate into the surface of the material with a load of 120kg or less, and an apex angle of 136°. Then, divide the area of indentation in the material by the load, and we get the Vickers hardness (HV) value (kgf/mm²).

3.Rockwell Hardness (HR)
When HB>450 or the sample is too small, making it impossible to apply the Brinell hardness, the Rockwell hardness measurement will take the place. A diamond cone with an apex angle of 120° or a steel ball with a diameter of 1.59-3.18mm is pressed into the surface of the material to be tested under a certain load, and the hardness of the steels is determined based on the depth of the indentation. According to the hardness of the test material, it is measured by three different scales:

The Rockwell Hardness is comprised of three different standards, i.e., HRA, HRB and HRC, referred to A scale, B scale, and C scale.

HRA: The hardness obtained by using a 60kg load and a diamond cone indenter, applicable for materials with an extremely high hardness (such as cemented carbide).

HRB: The hardness obtained by using a load of 100kg and a hardened steel ball with the diameter of 1.58mm, applicable for materials with a lower hardness (such as annealed steel, and cast iron, etc.)

HRC: The hardness obtained by using a 150kg load and a diamond cone indenter, applicable for materials with a very high hardness (such as hardened steel).

Steel hardness conversion table

There are so many different types of steel hardness tests, a conversion table, such as the one below, allows us to take one measure and estimate the relative hardness on another measurement scale.

RmN/mm2	HV	HB	HRC	RmN/mm2	HV	HB	HRC
250	80	76	–	1030	320	304	32.2
270	85	80.7	–	1060	330	314	33.3
285	90	85.2	–	1095	340	323	34.4
305	95	90.2	–	1125	350	333	35.5
320	100	95	–	1115	360	342	36.6
335	105	99.8	–	1190	370	352	37.7
350	110	105	–	1220	380	361	38.8
370	115	109	–	1255	390	371	39.8
380	120	114	–	1290	400	380	40.8
400	125	119	–	1320	410	390	41.8
415	130	124	–	1350	420	399	42.7
430	135	128	–	1385	430	409	43.6
450	140	133	–	1420	440	418	44.5
465	145	138	–	1455	450	428	45.3
480	150	143	–	1485	460	437	46.1
490	155	147	–	1520	470	447	46.9
510	160	152	–	1555	480	456	47.7
530	165	156	–	1595	490	466	48.4
545	170	162	–	1630	500	475	49.1
560	175	166	–	1665	510	485	49.8
575	180	171	–	1700	520	494	50.5
595	185	176	–	1740	530	504	51.1
610	190	181	–	1775	540	513	51.7
625	195	185	–	1810	550	523	52.3
640	200	190	–	1845	560	532	53
660	205	195	–	1880	570	542	53.6
675	210	199	–	1920	580	551	54.1
690	215	204	–	1955	590	561	54.7
705	220	209	–	1995	600	570	55.2
720	225	214	–	2030	610	580	55.7
740	230	219	–	2070	620	589	56.3
755	235	223	–	2105	630	599	56.8
770	240	228	20.3	2145	640	608	57.3
785	245	233	21.3	2180	650	618	57.8
800	250	238	22.2		660		58.3
820	255	242	23.1		670		58.8
835	260	247	24		680		59.2
850	265	252	24.8		690		59.7
865	270	257	25.6		700		60.1
880	275	261	26.4		720		61
900	280	266	27.1		740		61.8
915	285	271	27.8		760		62.5
930	290	276	28.5		780		63.3
950	295	280	29.2		800		64
965	300	285	29.8		820		64.7
995	310	295	31		840		65.3
					860		65.9
					880		66.4
					900		67
					920		67.5
					940		68