Effect of cooling rate on the microstructure and mechanical properties of high nitrogen stainless steel weld metal

The micro-structure and mechanical properties of high nitrogen stainless steel weld metals prepared under air and water cooling conditions were investigated and the effect of cooling rate on the micro-structure and mechanical properties of high nitrogen stainless steel weld metal was discussed in this study. The results indicated that an increase in the cooling rate would significantly increase the nitrogen content in the high nitrogen stainless steel weld metal, especially for the one with nitrogen content of 0.85%. Increasing cooling rate could result in the increase in the tensile strength of high nitrogen stainless steel weld metal, which was found to be strongly dependent on the nitrogen content in high nitrogen stainless steel weld wire. For the lower nitrogen content of high nitrogen austenitic stainless steel welding wire, increasing cooling rate could significantly improve the tensile strength of weld metal, but had no influence on the one of weld metal when the nitrogen content beyond 0.58% in the welding wire. The tensile strength of the joint reached 850 MPa finally.