Fatigue strength improvement of lap joints of thin steel plate using low-transformation-temperature welding wire

The fatigue strength of lap joints of thin steel plate was improved by using a developed low-transformation-temperature welding wire that induced the compressive residual stress around a welded part in the as-welded condition. The transformation of weld metal from austenite to martensite began around 180degreesC and finished around room temperature. This expansion of weld metal is constrained by the surrounding base metal and induces compressive residual stress. The mean stress effect due to the compressive residual stress improved the fatigue limit approximately 1.5 times.