How to represent the hardness of steel plate

The hardness of steel plates can be represented by different hardness indicators, commonly used methods include Brinell hardness (HB), Rockwell hardness (HRC), and Vickers hardness (HV).

Brinell hardness (HB): This is a commonly used method for expressing the hardness of steel plates in China, measured based on the indentation diameter. The Brinell hardness test is conducted by pressing a steel ball or hard alloy ball of a certain diameter into the surface of a specimen with a specified test force (F), and after a specified holding time, the test force is removed to measure the indentation diameter (D) on the surface of the specimen. The Brinell hardness value is the quotient obtained by dividing the test force by the surface area of the indentation sphere. Expressed in HBS (steel ball), the unit is N/mm ² (MPa).

Rockwell hardness (HRC): This is a method of measuring the hardness of a steel plate by the degree of elastic recovery after contact between a pitot drill bit and the steel plate. The Rockwell hardness test uses a diamond cone with a vertex angle of 120 ° or steel balls with diameters of 1.59 and 3.18mm, which are pressed into the surface of the tested material under a certain load. The hardness of the material is determined by the depth of the indentation. According to the different hardness of the test materials, there are three different scales to represent them: HRA, HRB, and HRC, among which HRC is used to measure materials with higher hardness.

Vickers hardness (HV): This is a method of representing the hardness of a steel plate by the area of indentation produced by the drill bit on the sample. The principle of Vickers hardness test is basically the same as Brinell hardness, which calculates the hardness value based on the load size per unit area of indentation. The difference is that the indenter used in the Vickers hardness test is a diamond regular pyramid.

In addition to the three commonly used hardness representation methods mentioned above, there are other hardness representation methods such as Shore hardness and Leeb hardness. It should be noted that different hardness representation methods cannot be directly converted, and the appropriate hardness representation method needs to be selected based on the specific material and hardness range.

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