steel tube

　　 Hot rolled seamless steel tube : hot rolling is related to the cold drawn, hot rolling is performed above the recrystallization temperature of the rolling. 　 　Hot-rolled seamless steel tube advantages: 　　Ingot casting can destroy tissue, grain refinement of steel and eliminate defects microstructure, so that the steel dense tissue mechanical properties are improved. This improvement is mainly reflected in the direction along the rolling direction to a certain extent, the steel is no longer isotropic; pouring formed bubbles, cracks and loose, can be welded at a high temperature and pressure. 　 　Hot-rolled seamless stee tube disadvantages: 　　1. After hot rolling, the steel inside the non-metallic inclusions (mainly sulphide and oxide, and silicates) is pressed into the sheet, delamination (interlayer) phenomenon. Layered in the thickness direction of the steel tension performance deteriorated significantly, and there may be an interlayer tear weld shrinkage. Weld local strain-...