焊丝含氮量及焊接电流对高氮钢焊缝组织和性能影响

针对高氮奥氏体不锈钢焊接过程中由于N元素逸出引起气孔、导致力学性能恶化的问题，利用相图计算软件设计并制备了含氮量为0.35%和0.85%两种奥氏体不锈钢焊丝，系统地研究了氮含量和焊接电流对高氮钢焊缝气孔倾向性、微观组织以及力学性能的影响规律. 结果表明，高氮钢焊缝气孔倾向和力学性能与焊接电流、焊丝氮含量密切相关：随着焊接电流增加，氮含量0.35%的高氮钢焊缝抗拉强度和断后伸长率均增加，未出现气孔；而氮含量0.85%的高氮钢焊缝具有很高的气孔倾向，抗拉强度和断后伸长率变化不大，当焊接电流增大到一定值后，气孔倾向性明显降低.

Effects of nitrogen content and welding current on microstructure and properties of the weld of high nitrogen austenite steel

In order to tackle the problems of porosity and resultant depression of mechanical properties induced by the escape of nitrogen gas during welding process of the high nitrogen stainless steel, two kinds of austenitic steel welding wire with nitrogen content of 0.35% and 0.85% were designed and prepared based on the results calculated by Thermo-Calc software. The effects of nitrogen content and welding processes on porosity, microstructure and mechanical properties of high nitrogen austenite steel weld were investigated. The results showed that the porosity and mechanical properties of high nitrogen austenitic stainless steel weld were strongly dependent on the welding current and the nitrogen content of welding wire. When the nitrogen content of wire was 0.35%, tensile strength and elongation increased as welding current increasing, and no porosity could be observed in the weld. When the nitrogen content of wire was 0.85%, the changes in tensile strength and elongation were negligible, and there were more porosities in the weld, the number of porosity in the weld was diminished sharply after the welding current increased to a critical value.