Improvement of the fatigue strength of aluminium alloy welded joints by high hardness and large specific gravity shot peening

Abstract

The shot peening method, which requires simple equipment and treatment, is extensively employed as a method to improve fatigue strength. However, conventional steel ball shot material has a low specific gravity, so high speed projection is required in order to improve fatigue strength; thus, the accompanying noise and high air flow are problems. Accordingly, in order to improve these aspects, high hardness and high specific gravity shot material has been developed with 1.7 times the hardness (HV1400) and approximately 1.9 times the specific gravity (approximately 14) compared with a conventional steel ball.^1,2