How much do you know about the hardness of stainless steel pipes?

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

(1) Brinell hardness (HB)

Press a hardened steel ball of a certain size (usually 10mm in diameter) into the surface of the material with a certain load (usually 3000kg) and keep it for a period of time. After the load is removed, the ratio of the load to the indentation area is the Brinell hardness (HB ).

How much do you know about the hardness of stainless steel pipes?

(2) Rockwell hardness (HR)

When HB> 450 or the sample is too small, the Brinell hardness test cannot be used and the Rockwell hardness measurement can be used instead. It uses a diamond cone with an apex angle of 120° or a steel ball with a diameter of 1.59 and 3.18mm, which is pressed into the surface of the material to be tested under a certain load, and the hardness of the material is obtained from the depth of the indentation. According to the hardness of the test material, it can be expressed in three different scales:

HRA: It is the hardness obtained with a 60kg load and a diamond cone indenter, and is used for extremely hard materials (such as cemented carbide, etc.).

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

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

(3) Vickers hardness (HV)

With a load of less than 120kg and a diamond square cone indenter with an apex angle of 136°, it is pressed into the surface of the material, and the surface area of ​​the material indentation pit is divided by the load value, which is the Vickers hardness (HV).