Hardness testing of cold-drawn seamless steel tube should take into account its mechanical properties, which is related to the deformation, stamping, cutting and other processing performance and quality of cold-drawn seamless steel tube. Therefore, all cold-drawn seamless steel tubes should be tested for mechanical properties. There are two kinds of testing methods for mechanical properties, one is tensile test and the other is hardness test. Tensile test is to make cold-drawn seamless steel tube into specimens, pull the specimens to fracture on a tensile testing machine, and then determine one or more mechanical properties, usually only the tensile strength, yield strength, elongation after breaking and section shrinkage. Tensile test is the most basic test method of mechanical properties of metal materials. Almost all metal materials, as long as the mechanical properties are required, have stipulated the tensile test. Especially for those materials whose shape is not easy to carry out hardness test, tensile test becomes the only means of testing mechanical properties. ? 硬度试验是将一个硬质压头按规定条件缓慢压入试样表面、然后测试压痕深度或尺寸，以此确定材料硬度的大小。硬度试验是材料力学性能试验中最简单、最迅速、最易于实施的方法。硬度试验是非破坏性的，材料硬度值与抗拉强度值之间有近似的换算关系。材料的硬度值可以换算成抗拉强度值，这一点具有很大的实用意义。?
Hardness test is to determine the hardness of the material by slowly pressing a hard indenter into the surface of the sample under specified conditions and then testing the indentation depth or size. Hardness test is the simplest, quickest and easiest method in material mechanical property test. Hardness test is non-destructive, and there is an approximate conversion relationship between hardness and tensile strength. The hardness value of the material can be converted into the tensile strength value, which has great practical significance. ?
Due to the inconvenience of tensile test and the convenience of conversion from hardness to strength, more and more people only test the hardness of materials and less test their strength. Especially due to the continuous progress and innovation of hardness tester manufacturing technology, some materials that could not directly test hardness, such as cold-drawn seamless steel tube, cold-drawn seamless steel tube sheet and cold-drawn seamless steel tube strip, are now possible to directly test hardness. Therefore, there is a tendency that the hardness test will gradually replace the tensile test. ?
Tensile test and hardness test are stipulated in most of the national standards for cold-drawn seamless steel tube materials. For those materials which are not convenient for hardness testing, such as cold-drawn seamless steel pipe, only tensile test is required. In the standard of cold-drawn seamless steel pipe, three hardness test methods, cloth, lo and vitamin D, are generally stipulated. The hardness values of HB, HRB (or HRC) and HV are determined. It is stipulated that only one of the three hardness values can be measured.
标签:   冷拔钢管 环氧地坪 地坪 环氧地坪漆 环氧地坪施工