Stainless steel pipe is a hollow long round steel, mainly used in industrial transportation pipelines and mechanical structural parts such as petroleum, chemical industry, medical treatment, food, light industry, mechanical instrumentation, etc. In addition, when the bending and torsional strength are the same, the weight is light, so it is also widely used in the manufacture of mechanical parts and engineering structures. It is also often used as furniture and kitchenware.
hardness
Stainless steel pipes generally use three hardness indexes of Brinell, Rockwell and Vickers to measure their hardness.
Brinell hardness
Among the stainless steel pipe standards, Brinell hardness is the most widely used, and the hardness of the material is often expressed by the indentation diameter, which is intuitive and convenient. However, it is not suitable for steel pipes with harder or thinner steel.
Rockwell hardness
The Rockwell hardness test of the stainless steel pipe is the same as the Brinell hardness test, which is the indentation test method. The difference is that it measures the depth of the indentation. The Rockwell hardness test is a widely used method, in which HRC is used second only to the Brinell hardness HB in the steel pipe standard. Rockwell hardness can be applied to the measurement of metal materials from extremely soft to extremely hard. It makes up for the Brinell method. It is simpler than the Brinell method, and the hardness value can be read directly from the dial of the hardness machine. However, because of its small indentation, the hardness value is not as accurate as the Brinell method.
Vickers hardness
The Vickers hardness test of stainless steel pipe is also an indentation test method, which can be used to determine the hardness of very thin metal materials and surface layers. It has the main advantages of the 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
Stainless steel pipes with an inner diameter of 6.0mm or more and a wall thickness of 13mm or less can use W-B75 Vickers hardness tester, which is very fast and simple to test, and is suitable for quick and non-destructive qualified inspection of stainless steel pipes. Stainless steel pipes with an inner diameter greater than 30mm and a wall thickness greater than 1.2mm use Rockwell hardness testers to test HRB and HRC hardness. For stainless steel pipes with an inner diameter greater than 30mm and a wall thickness less than 1.2mm, a surface Rockwell hardness tester is used to test HRT or HRN hardness. 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 the HR15T hardness. When the inner diameter of the stainless steel pipe is greater than 26mm, you can also use the Rockwell or surface Rockwell hardness tester to test the hardness of the inner wall of the pipe.
