SHOT PEENING METHOD FOR IMPROVING FATIGUE STRENGTH OF COIL SPRING

摘要

PURPOSE: To improve fatigue resistance by giving high compressive residual stress from the uppermost layer to the deep interior of a coil spring. ;CONSTITUTION: A coil spring thermally refined so as to be over Hv 550 in hardness of the base material is treated by shot peening while projecting shot grains previously cooled. Hereby, fatigue resistance of valve springs of an automobile engine or suspension springs can be remarkably improved, and hence this method is extremely useful for the industry.;COPYRIGHT: (C)1993,JPO&Japio