Abstract
The effect of weld metal on fatigue strength in type 430 ferritic stainless steel was investigated. Two weld metals with different chemical compositions, NbL1 and NbL2, had been used for the MIG butt welding of type 430. NbL2 with A1 and Ti showed finer grains in the weld microstructure than Nb1l. In both NbL1 and NbL2 welds, the hardness of heat affected zone (HAZ) was the highest due to the formation of hard acicular martensite. Fully reversed axial fatigue tests have been performed using smooth specimens of welds and base metal at ambient temperature in laboratory air. The fatigue strengths of both welds were increased compare with the base metal, which could be attributed to increase the hardness in weld zone. The fatigue strengths of NbL2 welds were slightly higher than those of NbL1 welds. It could be attributed to be finer grains in the NbL2 weld microstructure.
