What Is Brinell Hardness
Hardness refers to a material's ability to resist local deformation, especially plastic deformation, indentation, or scratches. It is an indicator of material softness and hardness.
According to different testing methods, hardness can be divided into three types. HB (Brinell hardness), HR (Rockwell hardness), and HV (Vickers hardness) metal materials hardness represents the ability of the material surface to resist plastic deformation caused by another object's indentation; The rebound method (Shore, Richter) is used to measure hardness, and the hardness value represents the magnitude of the metal's elastic deformation function.
Brinell Hardness (HB)
A quenched steel ball or hard alloy ball is used with a diameter of D as the indenter and pressed onto the surface of the specimen with the corresponding test force F. After a holding time, remove the test force and obtain an indentation with a diameter of d. The value obtained by dividing the test force by the indentation surface area is the Brinell hardness value, denoted by HBS or HBW.
The difference between HBS and HBW is the difference in the pressure head. HBS stands for Hardened Steel Balls, used to measure materials with a Brinell hardness value below 450, such as soft steel, gray cast iron, and non-ferrous metals. HBW indicates that the indenter is made of hard alloy and is used to determine materials with a Brinell hardness value below 650.
When other experimental conditions are the same for the same test block, the results of the two tests are different, and the HBW value is often greater than the HBS value, and there is no quantitative pattern to follow.
Since 2003, China adopted international standards and abolished steel ball indenters, using only hard alloy ball heads. Therefore, HBS is discontinued and all Brinell hardness symbols are represented by HBW. Many times, Brinell hardness is only expressed in HB, which refers to HBW. However, HBS is still occasionally seen in literature papers.
The Brinell hardness measurement method is applicable to cast iron, non-ferrous alloys, and various annealed quenched and tempered steels. It is not suitable for measuring samples or workpieces that are too hard, too small, too thin, and do not allow large indentation on the surface.
