Effects of TIG Process on Corrosion Resistance of 321 Stainless Steel Welding Joint

In this paper, the effects of different TIG welding parameters on corrosion resistance of 321austenitic stainless steel welding joint were studied. Intergranular corrosion, stress-strain curves of SSRT and the fracture surface of the welding joint were investigated by means of intergranular corrosion test, SCC test and SEM. The results showed that the intergranular corrosion cracks did not occur for all joints welded in the range of TIG welding current of 130A~190A. In pure water at room temperature, strain rate at the range of 1×10-5 s-1~1×10-6 s-1 had little effect on the maximum tensile strength of the material under the same welding conditions and the time of joint fracture increased as the strain rate decreased. At strain rate of 1×10-6 s-1, the maximum tensile strength of the joint welded in the current of 130A and 150A decreased significantly in the dyeing assistant and presented stress corrosion sensitivity. Joints welded in the current of 170A and 190A, showed excellent resistance to stress corrosion. Through the analysis of the fracture surface of joints, the joint welded in current of 130A presented a tendency to brittle fracture, while the joints in the current of 170 A and190 A were characterized with ductile fracture.