Mechanical properties of steel should be taken into consideration when testing its hardness which related to the quality and performance after deformation, stamping, cutting and other processing. Thus, all seamless steel pipes need mechanical property test, the test has two types: tensile test and hardness test.

Tensile test is use a seamless steel pipe sample, and then pull the sample on the machine till it’s broken, therefore can test its tensile strength, yield strength, and elongation. The tensile test is the most common method to test the mechanical property of metal material. As long as the mechanical property is required, all metal material need to have tensile test. Particularly for those metal materials have complicated shapes that are not easy to be tested, the tensile test is the only way to test its mechanical property.

Hardness test is use a indenter and pressed it into the surface of sample pipes slowly, then measure the depth or dimension of the indentation so that can get the hardness. The hardness test is the simplest and the most convenient method to test the mechanical property of certain material. The hardness test is non-destructive, and has similar values in terms of the relationship between hardness and tensile strength. The hardness of material can be converted into tensile strength values which have great practical significance.

Since the tensile test is not easy to undertake, and it’s convenient to converted hardness to strength, therefore, more and more manufactures choose to test hardness of material rather than its strength. As the development of manufacturing technique and testing technology, materials such as seamless steel pipes and stainless steel pipes which cannot test hardness directly in the past, now can test directly. Thus, the hardness test will gradually replace the tensile test.