Fatigue Strength in Stainless Steel Welds Developed Through Robotic Gas Metal Arc Welding

Abstract Welding is essential in the construction, aircraft, aerospace, and automotive industries. However, welded joints are sensitive to fatigue failure due to cyclic loading and fatigue crack propagation influenced by welding residual stresses (RS) distribution. Welding residual stresses are caused by differential thermal expansion and contraction of the weld metal and parent material. In and near the weld, residual stress levels can be very high, up to material yield strength magnitude in highly constrained situations, which is the case in most real structures. The residual stress in a welded joint can augment the externally applied load and cause structural failure. The fatigue life of the welding can be affected by the amount of electrical energy supplied during the welding, which induces tensile residual stress in the welds. This research analyzes the fatigue strength in duplex stainless steel 2205 (DSS) produced by a robotic welding process. The study presents the effect of heat input as a welding variable in the residual stress and fatigue life. Results showed that X-ray diffraction measurements along the center thickness reveal tensile residual stress in the fusion zone and near the adjacent weld region, and the fatigue life increases an average of 40% when the heat input increases by 65% in the welding process of DSS.