Evaluation of Structure and Properties of COR 13/4 (GX4CrNi13-4) Tungsten Inert Gas-Welded Steel

The effect of tungsten inert gas welding in combination with high alloyed filler materials on the microstructure and mechanical properties of COR 13/4 martensitic stainless steel were investigated by mechanical testing and metallography observation. The experimental results showed that using filler materials with higher Cr and Cr-Mo content increased the δ-ferrite content in the fusion zone. Higher Ni and N content in the filler material led to an increase in the retained austenite content in the heat-affected zone (HAZ). Higher C concentration in filler material then led to dramatically reduced impact toughness of the weld due to embrittlement of martensite structure and the presence of M₂₃C₆ and σ phase in the weld and along the fusion line. The phase composition close to the fusion zone affected the wear rate, tensile properties and hardness. The results show a lower wear rate for samples with a lower amount of martensite and a higher amount of Fe_9.7Mo_0.3 and Fe_10.8Ni. The ultimate tensile strength (UTS) results show that the presence of the Fe_9.7Mo_0.3 or Fe_10.8Ni phase in HAZ contributed to an increase in the UTS value compared with the presence of the martensite phase.