Effect of Shot Peening on Welding Residual Stress of 2219 Aluminum Alloy Friction Stir Welding

Abstract

Friction stir welding (FSW) and shot peening were performed on 2219 aluminum alloy plates.The residual stresses generated by FSW and shot peening were measured using X-ray diffraction (XRD)， and the distribution characteristics of residual stresses were analyzed.The effects of parameters such as shot diameter， shot material， and spraying distance on the distribution of residual stresses in FSW were studied.Results showed that there was a large residual tensile stress near the weld zone after welding， and the average stress within ±20 mm of the weld center line was as high as 100.9 MPa， while the base metal area far away from the weld was close to zero stress.After shot peening，the distribution of residual stress of sample changed significantly， surface residual stress was manifested as compressive stress， and the value of compressive stress first increased and then decreased with the increase of depth， and finally remained as tensile stress.Increasing the shot diameter could increase the maximum residual compressive stress value and the depth of the residual compressive stress layer.However， when the shot diameter continued to increase to 1.2 mm，the maximum residual compressive stress value no longer increased.The optimal distribution of residual compressive stress could be obtained by selecting the appropriate shot material.The maximum residual compressive stress and the depth of the residual compressive stress layer firstly increased and then decreased with the increase of the spraying distance.

Keywords

• shot peening|2219 aluminum alloy|friction stir welding|residual stress