Effect of Shot Peening on Fatigue Strength of Welded Joints For Low Carbon Steel

Abstract

The aim of this work is to study the effect of the time of shot peening withsteel balls of 1.25 mm in diameter on fatigue strength of butt joints for low carbonsteel (1020 AISI) welded by metal arc welding shielded with CO2 gas(MIG/MAG). All fatigue tests were of the rotary bending type at mean stress ofzero for welded unpeened samples and shot peened samples at various times.It was found that all the shot peen times of (10,20,30) minutes have improvedthe fatigue strength and the best strength has been achieved at the time 20 minutesbecause of the high compressive stresses induced by the shot peen process and inaddition to the denteritic microstructure in the weld zone for unpeened samples .