Heat treatment process for threaded flanges

　　In the process of heat treatment of threaded flanges, annealing cooling speed is the slowest, normalizing cooling speed is faster, quenching cooling speed is faster. But there are different requirements for different grades of steel, such as air-hardened steel can be normalized as cooling rate for hardening. Threaded flanges are connected and uninterrupted. When the metal is heated, the threaded flanges pipe often oxidizes when the workpiece is exposed to the air. Decarburization (that is, the reduction of carbon content on the surface of iron and steel parts) has a negative effect on the surface properties of the parts after heat treatment. The metal parts of ANSI B16.47 Class 150-2500 Threaded Flanges should normally be controlled in atmospheres or protective atmospheres. Heating in molten salt and neutralized in vacuum can also be protected by coating or packaging.