What is HB? Convert from HB to HRC

11/01/2020

One of the important criteria used to measure steel strength is hardness. And now there are many measurement units used besides HRC, including HB, HV, HRA, HRB, HRD.

Today, let's learn about one of the common measurement units of Sevit which is HB hardness and convert from HB to HRC.

1. Definition of hardness

Hardness is one of the basic properties of steel in general and special steel in particular such as SKD11, DC11, SKD61, SCM440H, etc. The harder the material is to deform, the higher the hardness.

What is HB? Convert from HB to HRC

Hardness reflects the abrasion resistance and impact of steel. The ability to resist surface deformation when impacting a harder material greatly depends on hardness.

2. What is the definition of HB hardness method?

The Brinell Hardness (HB) method was invented by Johan August Brinell, a Swedish engineer in August 1900.

The Brinell Hardness (HB) is determined by pressing a hard steel sphere with diameter D in a given period of time, and the steel ball will penetrate the test surface. In this method, the hardness index, HB, is determined by mean pressure, expressed in Newton (N) per 1 mm² of the sphere area left by the dent.

3. Definition of Rockwell C (HRC)

According to this method of measurement, we have a diamond tip with an angle of 120 ° and a radius of R = 0.2 (mm) or hardened steel ball with a diameter of 1/16, 1/8, 1/4 , 1/2 inch is pressed on the steel surface under test. Hardness is determined by taking the action of a diamond or a ball with two successive pressures.

For Rockwell C (HRC) we use a diamond tip with a pressure of 150 Kg to measure the medium and high hardness of special steels such as SKD11, DC11, SKD61, SCM440H after heat treatment.

4. Conversion table from HB to HRC

Brinell (HB)	Rockwell C (HRC)	Brinell (HB)	Rockwell C (HRC)
		695	64
154	1	681	63
156	2	658	62
160	3	642	61
163	4	627	60
166	5	613	59
167	6	601	58
170	7	592	57
175	9	572	56
180	10	552	55
183	11	534	54
186	12	513	53
190	13	504	52
191	14	486	51
199	15	469	50
203	16	468	49
208	17	456	48
212	18	445	47
216	19	430	46
223	20	419	45
229	21	415	44
233	22	402	43
240	23	388	42
245	24	375	41
250	25	373	40
255	26	360	39
262	27	348	38
264	28	341	37
271	29	331	36
277	30	322	35
290	31	314	34
300	32	308	33

In addition to HRC and HB, HV, HRA, HRB, HRD hardness measurement units are often used for softer materials that HRC and HB measure incorrectly.

Hopefully the above information will solve the problems that readers are having. If you want to get more specific advice about industrial steels, readers can contact 0332 91 61 61 or chat online with us.

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