Hardness Test of 40Cr Carbon Seamless Steel Tubes

American Standard carbon seamless steel pipe conduct mechanical performance testing. Mechanical properties of test methods are divided into two categories, one is the tensile test, one is the hardness test.

Tensile tests are made of seamless steel tube samples, the tensile test machine will pull the specimen to the fracture, and then measured one or more mechanical properties, usually only the determination of tensile strength, yield strength, elongation and rate of reduction in area. Tensile test is the most basic metal mechanical properties of test methods, almost all of the metal materials, as long as the mechanical properties are required, are provided for tensile testing. In particular, tensile tests are the only means of testing the mechanical properties of materials that are not easily tested for their hardness.

Hardness test is a hard indenter according to the provisions of the conditions slowly pressed into the sample surface, and then test indentation depth or size, in order to determine the size of the hardness of the material. Hardness test is the mechanical properties of materials testing the most simple, the most rapid and easiest to implement the method. Hardness test is non-destructive, the hardness value of the material and the tensile strength value between the approximate conversion relationship. The hardness of the material can be converted into tensile strength value, which has great practical significance.

As the tensile test is not easy to test, and converted from the hardness to the intensity is very convenient, so more and more people only test the hardness of the material and less test its strength. In particular, due to the hardness of manufacturing technology advances and innovation, some of the original can not directly test the hardness of materials, such as seamless steel tubes, stainless steel, etc., are now possible to directly test the hardness. Therefore, there is a tendency to gradually replace the tensile test with a hardness test.