Fatigue Strength Improvement of Low Carbon Steel Resistance Spot Welds by the StressWave™ Process 2005-01-0903

In the automotive industry, resistance spot welding (RSW), or spot welding, has been and continues to be an important process in body structure assembly. The optimization of the number, location, and quality of spot welds is a major economic consideration. In order to improve fatigue strength of low carbon steel RSWs, a StressWave cold working process has been recently adapted to RSWs. The cold working process generates uniform and consistent large zones of compressive residual stresses in resistance spot-welded low carbon steel structures using a specially designed indentation device. The effect of the StressWave cold working process parameters on the fatigue properties of the RSWed specimens is investigated. Comparisons of the fatigue strength and fractography between the as-resistance spot-welded specimens and the StressWave cold worked resistance spot-weld specimens are made in this investigation. In addition, an axisymmetric finite element (FE) model is used to complement experimental results. The influence of the StressWave process parameters on fatigue life is discussed.