高氮奥氏体不锈钢平衡态下焊缝含氮规律研究
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摘要
氮损失是高氮钢焊接中面临的主要问题,文中在平衡试验条件下研究了保护气体组成、焊丝成分及冷却速度等因素对熔池中氮含量变化的影响规律。经系统研究可知,增加焊丝中的氮含量利于提高熔池总的氮含量,焊丝中的氮含量由0.15%增加到0.60%的过程中,熔池氮含量变化趋势较明显,而当焊丝氮含量超过0.60%后,其对熔池氮含量的影响不再明显;增加保护气体中氮气比例可使钢中氮含量持续增加,同时当体系总压强由0.1 MPa增至0.15 MPa时,熔池中氮含量相应地由0.48%提高到0.61%,增幅达27%;提高焊件的焊后冷却速度可便焊缝中的氮含量增加。平衡试验条件下,水冷、油冷和空冷条件下钢中的氮含量高于炉冷条件下的氮含量,实际焊接中可通过提高焊后凝固速度达到熔池固氮的目的。平衡试验条件下的研究结论为高氮钢焊接过程提供了有力的理论指导。
The overflow of nitrogen was a predominant problem that should be solved for the welding of high nitrogen austenitic stainless steel. In the study, the effects of the composition of protective gas and welding wire, and cooling rate on the changes of nitrogen content in molten pool were investigated on the high nitrogen stainless steel under equilibrium conditions. The results indicated that an increase in the nitrogen content of welding wire was beneficial for the increasing of nitrogen content in molten pool. The nitrogen content in molten pool changed significantly when the nitrogen content in welding wire increased from 0.15% to 0.60%, but showed no obvious variation when that beyond 0.60%. Increasing the proportion of nitrogen in the protective gas could increase the nitrogen content in molten pool. Besides, the increase of cooling rate could also increase the nitrogen content in welding pool of high nitrogen austenitic stainless steel. The nitrogen content in molten pool under water cooling, oil cooling and air cooling conditions were higher than that under furnace cooling condition. These results would provide a theoretical guidance for the welding operation of high nitrogen austenitic stainless steel.
The overflow of nitrogen was a predominant problem that should be solved for the welding of high nitrogen austenitic stainless steel. In the study, the effects of the composition of protective gas and welding wire, and cooling rate on the changes of nitrogen content in molten pool were investigated on the high nitrogen stainless steel under equilibrium conditions. The results indicated that an increase in the nitrogen content of welding wire was beneficial for the increasing of nitrogen content in molten pool. The nitrogen content in molten pool changed significantly when the nitrogen content in welding wire increased from 0.15% to 0.60%, but showed no obvious variation when that beyond 0.60%. Increasing the proportion of nitrogen in the protective gas could increase the nitrogen content in molten pool. Besides, the increase of cooling rate could also increase the nitrogen content in welding pool of high nitrogen austenitic stainless steel. The nitrogen content in molten pool under water cooling, oil cooling and air cooling conditions were higher than that under furnace cooling condition. These results would provide a theoretical guidance for the welding operation of high nitrogen austenitic stainless steel.
引文
[1]Mudali U K,Raj B.High Nitrogen Steels and Stainless Steels[M].Pangbourne:Alpha Science International Lid,2004.
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[5]姜周华,陈兆平,黄宗泽.不锈钢冶炼及凝固过程氮的控制[J].钢铁,2005,40(3):32-35.
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[2]Helzgruber W.New ESR technology for new and improved products[C]//Proceeding of the 7th International Conference on Vacuum Metallurgy.Tokyo:Japan,1982:1 452-1 458.
[3]Stein G,Huchlenbroich I.Manufacturing and application of high nitrogen steels[J].Materials and Manufacturing Processes,2004,19(1):7-17.
[4]张国富,陈国良.VOD炉冶炼0Cr18Ni9不锈钢氮气增氮工艺研究[J].上海金属,1998,20(6):41-44.
[5]姜周华,陈兆平,黄宗泽.不锈钢冶炼及凝固过程氮的控制[J].钢铁,2005,40(3):32-35.
[6]Woo I,Kikuchi Y.Weldaility of high nitrogen stainless steel[J].ISIJ International,2002,42(12):1 334-1 343.
[7]Feichtinger H K,Stein G.Melting of high nitrogen steels[J].Materials Science Forum,1999:261-270.