Detailed introduction of stainless steel pipe

Hardness
Stainless steel pipes generally use Brinell, Rockwell and Vickers hardness indicators to measure their hardness.

Brinell hardness
In stainless steel pipe standards, Brinell hardness is the most widely used, often expressed by the indentation diameter to indicate the hardness of the material, which is both intuitive and convenient. However, steel pipes with harder or thinner steel are not applicable.

Rockwell hardness
The Rockwell hardness test of stainless steel pipe, like the Brinell hardness test, is an indentation test method. The difference is that it measures the depth of the indentation. The Rockwell hardness test is currently a widely used method, in which HRC is used in steel pipe standards second only to Brinell hardness HB. Rockwell hardness can be applied to the determination of extremely soft to very hard metal materials, it makes up for the Brinell method, simpler than the Brinell method, can directly read the hardness value from the dial of the hardness machine. However, due to its small indentation, the hardness value is not as accurate as the Brinell method.

Vickers hardness
The Vickers hardness test for stainless steel pipes is also an indentation test method that can be used to determine the hardness of very thin metal materials and surface layers. It has the main advantages of Brinell and Rockwell methods, and overcomes their basic shortcomings, but it is not as simple as the Rockwell method, and the Vickers method is rarely used in steel pipe standards.

Hardness testing
Annealed stainless steel pipe with inner diameter above 6.0mm and wall thickness below 13mm can use W-B75 type Wechsler hardness tester, which is very fast and simple to test, suitable for fast and non-destructive inspection of stainless steel pipe. Stainless steel pipe with inner diameter greater than 30mm and wall thickness greater than 1.2mm is tested by Rockwell hardness tester to test HRB and HRC hardness. Stainless steel pipe with inner diameter greater than 30mm and wall thickness less than 1.2mm is tested HRT or HRN hardness by using surface Rockwell hardness tester. For stainless steel pipes with an inner diameter of less than 0mm and greater than 4.8mm, the Rockwell hardness tester for pipes is used to test HR15T hardness. When the inner diameter of the stainless steel pipe is greater than 26mm, the hardness of the inner wall of the pipe can also be tested with Rockwell or surface Rockwell hardness tester.