It is intuitive and convenient to express the hardness of Sanitary Valve by indentation diameter. But it is not suitable for steel pipes with harder or thinner steel. The Rockwell hardness test of stainless steel pipe is the same as the Brinell hardness test, that is, the indentation test method. The difference is that it measures the depth of the indentation. The Rockwell hardness test is a widely used test method at present. It can only be used in steel pipe standards after the Rockwell hardness reaches HB.

Rockwell hardness can be used to measure metal materials from extremely soft to extremely hard. It makes up for the shortcomings of the Brinell method. It is simpler than the Brinell hardness tester method, and the hardness value can be read directly from the hardness tester dial. But due to the small indentation, the hardness value is not as accurate as the Brinell hardness method. The Vickers hardness test of stainless steel pipe is also an indentation test method, which can be used to measure the hardness of ultra-thin metal materials and surface layers.

It has the main advantages of the Brinell method and the Rockwell method, and overcomes their basic shortcomings, but it is not as simple as the Rockwell method, and the Vickers method is less used in steel pipe standards. [BR][BR]The inner diameter of stainless steel pipe is greater than 6.0 mm, and the wall thickness of annealed stainless steel pipe is less than 13 mm. W-B75 Webster hardness tester can be used. This method is fast, simple and suitable for rapid non-destructive testing of stainless steel pipes.

The HRB and HRC hardness of stainless steel pipes with a diameter greater than 30 mm and a wall thickness greater than 1.2 mm were measured using a Rockwell hardness tester. The surface Rockwell hardness tester was used to perform HRT or HRN hardness tests on stainless steel pipes with an inner diameter greater than 30 mm and a wall thickness less than 1.2 mm. For stainless steel pipes with an inner diameter less than 0 mm and greater than 4.8 mm, a special Rockwell hardness tester was used to perform HR15T hardness tests. When the inner diameter of the stainless steel pipe is greater than 26 mm, the hardness of the inner wall of the pipe can also be measured using a Rockwell hardness tester or a surface Rockwell hardness tester.