(1) The screw is made of 38CrMoAlA, 40Cr or 45# steel. […]
(1) The screw is made of 38CrMoAlA, 40Cr or 45# steel.
(2)The blank of the screw should be forged and formed.
(3)After the rough machining of the screw, the quality of the screw should be quenched and tempered, and the hardness is HB=260 to 290.
(4) The precision of the outer circle after the machining of screw essence should meet the requirement of GB180 - 79 and 8.
(5)Screw thread part of the rough hammer of a hundred million value: the two sides of the thread are not more than 1.6um, the bottom of the thread groove and the outer circle are not more than 0.8pm.
(6)The thread surface nitriding, nitriding depth of 0.3 ~ 0.6mm hardness of HV=700~8400
(7)The brittle screw is less than 2.