Effect of dilution on fatigue behaviour of welded joints produced by low-transformation-temperature fillers

Abstract

ABSTRACTLow-transformation-temperature (LTT) fillers with various martensitic transformation start (Ms) temperatures were used to produce fillet welds. In comparison with conventional welds, the fatigue strength of the LTT fillet welds offers a significant improvement, with a minimum increase of 145%. Owing to the substantial dilution of base metal, the Cr and Ni alloying elements in the LTT weld metals decrease, resulting in an increase of the Ms temperatures. Therefore, the fillet welds produced using the LTT filler material with the lower Ms temperature (92°C) exhibit a larger compressive residual stress and higher fatigue strength.