在铝件上加工内螺纹 ,若采用攻丝后装配 ,由于强度差等原因 ,在装配过程中 ,铝件上的内螺孔常会发生烂牙。为此 ,可采用内螺纹自攻工艺 ,即在铝件上加工出底孔 ,用钢制的螺栓直接装配在铝件上。在螺纹自攻过程中 ,铝件内孔壁发生塑性变形 ,部分铝材受钢制螺栓的螺牙挤压 ,使挤? In the aluminum parts of the internal thread, tapping after the assembly, due to poor strength and other reasons, the assembly process, the aluminum screw on the internal often rotten teeth. To this end, the internal thread self-tapping process can be used, that is, the bottom of the hole in the aluminum, steel bolts installed directly on the aluminum. In the thread self-tapping process, the plastic deformation of the inner wall of the aluminum part of the aluminum by the steel screw thread extrusion, so squeeze?