Seamless steel pipe refers to the steel pipe made of a whole piece of metal without joints on the surface. According to the production method, it can be divided into hot rolling tube, cold rolling tube, cold drawing tube, sa572 grade 50 structural steel, extrusion tube and spinning tube. According to the shape of the section, it can be divided into two types: circular and irregular. The seamless tube has a maximum diameter of 650 mm (expanding tube) and a minimum diameter of 0.3 mm (capillary tube), which can be divided into thick walled tube and thin walled tube according to the thickness.
For Q235 steel, Q represents the yield limit of this material, and the following 235 refers to the yield value of Q235 steel, which is about 235 MPa. The sa572 grade 50 structural steel, Q235 steel yield strength decreases with the increase of the thickness of the material.
After the steel plate is produced from the original factory, it will pass through a series of transportation and storage links and then be delivered to the processing workshop. During this period of time, the steel plate surface will contact with the air continuously, which will inevitably produce a layer of oxide skin. The oxide skin is a difficulty in the treatment process. It has high melting point, is not easy to burn and dissolve, increases preheating time, reduces cutting speed. Therefore, the surface of the sa572 grade 50 structural steel plate should be derusted before cutting.
The purpose of sa572 grade 50 structural steel quenching is to transform the supercooled austenite into martensite or bainite to obtain a martensite or bainite structure, and then cooperate with tempering at different temperatures to greatly improve the strength, hardness, performance, fatigue strength, toughness, and wear resistance etc. of sa572 grade 50 structural steel. So as to meet the different use requirements of various mechanical parts and tools. Quenching can also help to get the ferromagnetic, corrosion resistance and other special physical and chemical properties of certain special steels.