According to the classification of metallographic structure, stainless steel sheets mainly divided into five types: austenitic stainless steel, ferritic stainless steel, austenitic ferritic stainless steel, martensitic stainless steel and precipitation hardening stainless steel. 

Stainless steel sheets include hot-rolled stainless steel and cold-rolled stainless steel , which are supplied in various heat treatment states such as annealing, quenching and tempering, solid solution, quenching or tempering.
In American standards, Rockwell hardness test is preferred, supplemented by Brinell hardness test, and Vickers hardness test is rarely used. Because they think that Vickers hardness test is mainly used for Metal Research and test of thin and small parts.

Rockwell hardness test

Brinell hardness test

Vickers hardness test
In China and Japan standards, there are three hardness tests at the same time. One of them can be selected according to the thickness and state of stainless steel sheet and its own conditions.
The hardness test method of stainless steel sheet/ plate is as follows:
For stainless steel plate with thickness greater than 1.2mm, use Rockwell hardness tester to test HRB and HRC hardness.
For stainless steel plate with thickness of 0.2 ~ 1.2mm, HRT or hrn hardness shall be tested by surface Rockwell hardness tester.
For stainless steel plate with thickness less than 0 2mm, the hardness of hr30tm shall be tested by surface Rockwell hardness tester and diamond point anvil.