Fatigue Strength Improvement of Welded Joints by Low Transformation Temperature Welding Material

Abstract

Fatigue strength of welded joints were improved by inducing the compressive residual stress around fatigue critical area by mean of low transformation temperature welding material which expands around room temperature due to the transformation from austenite to martensite. In the case of box welds, the fatigue strength at 2×10⁷ cycles was doubled without preheating and PWHT. In the case of box section welded member containing longitudinal weld lines, the fatigue strength at 2×10⁶ cycles was improved about 1.3 times of the usual joints.