Carburizing processing of seamless steel pipe, is surface treatment method on seamless steel pipe, the use of carburizing mostly low carbon steel or low alloy steel, the specific method is to place the workpiece with activated carburizing medium, heated to 900--950 degrees celsius single-phase austenite area, soaking enough time, so that carburizing media decomposition of the activated carbon atoms into the steel surface, so as to obtain high-surface surface, the heart still retain the original ingredients.
Tempering and the cause of the crack
Carburizing layer after grinding the surface caused by the phenomenon of softening, known as the grinding process produced by the tempering. This is due to grinding when the processing feed too fast, grinding wheel hardness and size or speed selection improperly, or grinding process is not sufficient cooling, are prone to such defects. This is because the heat at the time of grinding makes the surface soften. Grinding produces a tempering defect that reduces the wear resistance of the part.
The surface of the hexagonal crack, which is because the surface of the hard wheel by excessive grinding, and heat caused. But also with the heat treatment of tempering, residual internal stress is too large. After the acid erosion, any defective parts were black, with no defects to distinguish between. This is the heat generated when grinding is tempered. So that the body of the body into the body of the reason. In fact, the crack can be seen after grinding the naked eye.
