Brinell Hardness

Brinell hardness was proposed by Swedish engineer A. Brinell in 1900. It is widely used in engineering technology, especially in the mechanical and metallurgical industries. The hardened steel ball of a certain size is pressed into the surface of the material with a certain test force and kept for a period of time, after removal of the force, the ratio of the test force to the surface area of indentation is the Brinell hardness value (HB), and the unit is kgf / mm² ( N / mm²). The formula for Brinell hardness HB is (d is diameter of the   indentation):

The Brinell hardness range is HBW8 ~ 650. Generally speaking, the smaller the Brinell hardness value, the softer the material, the larger the indentation diameter; conversely, the larger the Brinell hardness value, the harder the material, the smaller the indentation diameter. The symbol of Brinell hardness is expressed by HBS or HBW. HBS indicates that the indenter is a hardened steel ball, it is used to determine 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 a hard alloy, which is used to measure materials with a Brinell hardness value below 650.

Brinell hardness (HB) is generally used when the material is soft, such as non-ferrous metals, steel before heat treatment or after annealing, it is not suitable to measure samples that are too hard, too small, too thin, and the surface does not allow large indentations Artifact. Rockwell hardness (HRC) is generally used for materials with higher hardness, such as hardness after heat treatment and etc.. Under certain conditions, HB and HRC can be exchanged by looking up tables. Its mental arithmetic formula can be roughly written as: 1HRC≈10HB.