Seamless steel pipes should conduct mechanical performance testing. Seamless steel pipes are widely used in manufacturing structures and mechanical parts, such as petroleum drilling rods, automotive transmission shafts, bicycle frames, and steel scaffolds used in construction construction. Materials and processing hours have been widely made of steel pipes. Mechanical performance testing methods (METHOD) are mainly divided into two types, one is stretching test, and the other is Hardness test.
The tensile test is to control seamless steel into samples. Pull the sample to the break on the stretch test machine, and then determine one or several mechanical properties. Generally, only the tensile strength, the yield strength, the elongation of the post -disconnection, and the elongation of the stretch rate of reduction in area. The 20G high -pressure boiler tube is used in the boiler component components, which is generally used in boiler applications below 39 kg. In order to use it under higher pressure, the heating surface tube is often designed very thick.
In order to reduce thermal resistance and save steel, to ensure the safety of high or high -pressure boiler steel, and at the same time to reduce the amount of steel, 16mng is generally used. At the same time, there are special steels that add metal and non -metal materials such as rare earth, magnesium, and non -metal materials. This will improve the performance of boiler steel, reduce the consumption of steel, and reduce thermal resistance. The stretch test is the most basic mechanical performance test method (METHOD). Almost all metal materials are required to stipulate the stretch test as long as they have requirements for mechanical performance. Especially those materials that are not easy to conduct hardness tests, stretch tests have become the only mechanical performance testing means.
The hardness test is to slowly press a hard pressure head into the surface of the sample according to the prescribed conditions, and then test the depth or size of the indentation to determine the size of the material hardness. Hardness test is the simplest, fastest, and easiest way to implement the material performance test. The hardness test is non -destructive, and there is a similar conversion relationship between the hardness value of the material and the tensile strength. The hardness of the material can be converted into the tensile strength value, which is of great practical significance.
Because the tensile test is inconvenient to test, and it is convenient to convert from hardness to the intensity, people are more and more test only testing the hardness of the materials and less testing their strength. The seamless steel pipe has a large -time section, which is used as a pipeline for transporting fluids, such as the pipelines of oil, natural gas, gas, water, and certain solid materials. Compared with solid steel such as steel pipes and round steel, when the anti -bending and anti -twist strength strength is the same, the weight is light, which is an economic section steel.
Especially due to the continuous progress and innovation of hardness meter manufacturing technology, some materials that could not directly test hardness, such as seamless steel pipes, stainless steel (stainless acid -resistant steel) boards, and stainless steel belts, etc., are now possible to test hardness directly. Therefore, a hardness test gradually replaces the trend of stretching test.
