Abstract：During the production of the screw rod，the surface of the screw rod appeared peeled off. Macroscopic，scanning electron microscope，metallographic microscope and spectroscopy and other methods were used to analyze the causes of peeling off the nitriding surface of the screw. The results showed that the reason for peeling off of the pitting on the surface of the screw was that the temperature was too high when grinding to the corner of the local screw thread before nitriding treatment，so that the slight intergranular cracks appeared at the corners，and its nearby surfaces and the shallow surface layer. With subsequent grinding，the corners were easily peeled off to form pitting.
2019, Vol. 37 
