Problems of heat treatment of shafts

Because heat treatment only changes the internal organization and structure, does not change the shape, so the status quo of the part after heat treatment is basically unchanged (of course, the heat treatment process cracked to be another story), but because there is a heating and cooling process, which will lead to a certain degree of deformation, so the heat treatment is usually arranged before the finishing process. Rough machining to go after the tempering, blanks to go to the tempering can be, of course, if the rough machining hardness is too high, processing difficulties, it is taken after the tempering and then rough machining, and then finish machining.