Comparison Table of Rockwell Hardness, Brinell hardness Hardness and Vickers Hardness

 　　Hardness represents the ability of a material to resist hard objects pressing into its surface. It is one of the important performance indicators of metal materials. Generally, the higher the hardness, the better the wear resistance. The commonly used hardness indicators are Brinell hardness hardness, Rockwell hardness and Vickers hardness.

　　1. Brinell hardness (HB)

　　Press a hardened steel ball of a certain size (generally 10mm in diameter) into the surface of the material with a certain load (generally 3000kg) for a period of time. After unloading, the ratio of the load to the indentation area is the Brinell hardness hardness value (HB), in kilograms of force/mm2 (N/mm2).

　　2. Rockwell hardness (HR)

　　When HB>450 or the sample is too small, Brinell hardness hardness test cannot be used, but Rockwell hardness measurement can be used instead. It uses a diamond cone with a top angle of 120 ° or a steel ball with a diameter of 1.59 or 3.18mm to press into the surface of the tested material under a certain load, and the hardness of the material is determined from the depth of the indentation. According to the hardness of the test material, there are three different scales to represent:

　　HRA: It is the hardness obtained using a 60kg load and a diamond cone press, used for materials with extremely high hardness (such as hard alloys).

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

　　HRC: It is the hardness obtained using a 150kg load and a diamond cone press, used for materials with high hardness (such as quenched steel).

　　3. Vickers hardness (HV)

　　Press a diamond square cone indenter with a load of less than 120kg and a top angle of 136 ° into the surface of the material, and divide the surface product of the material indentation by the load value to obtain the Vickers hardness HV value (kgf/mm2).

　　Note: In Rockwell hardness, A, B, and C in HRA, HRB, and HRC are three different standards, called scale A, scale B, and scale C. The Rockwell scale is one of several common indentation hardness tests used today. The initial pressure of the three scales is 98.07N (10 kgf). Finally, the hardness value is calculated according to the indentation depth. Scale A uses a spherical cone diamond shaped indenter, which is then pressurized to 588.4N (60kgf); Scale B uses a steel ball with a diameter of 1.588mm (1/16 inch) as the pressure head, and then pressurizes it to 980.7N (equivalent to 100kgf); Scale C uses the same spherical cone diamond shape as scale A as the pressure head, but the applied force is 1471N (150kgf). Therefore, scale B is suitable for relatively soft materials, while scale C is suitable for harder materials. Practice has proven that there is an approximate corresponding relationship between various hardness values of metal materials, as well as between hardness values and strength values. Because the hardness value is determined by the initial plastic deformation resistance and the continuous plastic deformation resistance, the higher the strength of the material, the higher the plastic deformation resistance, and the higher the hardness value. But the conversion relationships of various materials are not consistent.

　　2、 Hardness comparison table:

　　According to the German standard DIN50150, the following is the comparison table of steel tensile strength, Vickers hardness, Brinell hardness hardness and Rockwell hardness in the common range.

tensile strength Rm N/mm2	Vickers hardness HV	Brinell hardness HB	Rockwell hardness HRC
1030	320	304	32.2
1060	330	314	33.3
1095	340	323	34.4
1125	350	333	35.5
1115	360	342	36.6
1190	370	352	37.7
1220	380	361	38.8
1255	390	371	39.8
1290	400	380	40.8
1320	410	390	41.8
1350	420	399	42.7
1385	430	409	43.6
1420	440	418	44.5
1455	450	428	45.3
1485	460	437	46.1
1520	470	447	46.9
1555	480	(456)	47.7
1595	490	(466)	48.4
1630	500	(475)	49.1
1665	510	(485)	49.8
1700	520	(494)	50.5
1740	530	(504)	51.1
1775	540	(513)	51.7
1810	550	(523)	52.3
1845	560	(532)	53.0
1880	570	(542)	53.6
1920	580	(551)	54.1
1955	590	(561)	54.7
1995	600	(570)	55.2
2030	610	(580)	55.7
2070	620	(589)	56.3
2105	630	(599)	56.8
2145	640	(608)	57.3
2180	650	(618)	57.8
	660		58.3
	670		58.8
	680		59.2
	690		59.7
	700		60.1
	720		61.0
	740		61.8
	760		62.5
	780		63.3
	800		64.0
	820		64.7
	840		65.3
	860		65.9
	880		66.4
	900		67.0
	920		67.5
	940		68.0

tensile strength Rm N/mm2	Vickers hardness HV	Brinell hardness HB	Rockwell hardness HRC
1030	320	304	32.2
1060	330	314	33.3
1095	340	323	34.4
1125	350	333	35.5
1115	360	342	36.6
1190	370	352	37.7
1220	380	361	38.8
1255	390	371	39.8
1290	400	380	40.8
1320	410	390	41.8
1350	420	399	42.7
1385	430	409	43.6
1420	440	418	44.5
1455	450	428	45.3
1485	460	437	46.1
1520	470	447	46.9
1555	480	(456)	47.7
1595	490	(466)	48.4
1630	500	(475)	49.1
1665	510	(485)	49.8
1700	520	(494)	50.5
1740	530	(504)	51.1
1775	540	(513)	51.7
1810	550	(523)	52.3
1845	560	(532)	53.0
1880	570	(542)	53.6
1920	580	(551)	54.1
1955	590	(561)	54.7
1995	600	(570)	55.2
2030	610	(580)	55.7
2070	620	(589)	56.3
2105	630	(599)	56.8
2145	640	(608)	57.3
2180	650	(618)	57.8
	660		58.3
	670		58.8
	680		59.2
	690		59.7
	700		60.1
	720		61.0
	740		61.8
	760		62.5
	780		63.3
	800		64.0
	820		64.7
	840		65.3
	860		65.9
	880		66.4
	900		67.0
	920		67.5
	940		68.0