糊状区保温时间对201奥氏体不锈钢氮含量和气孔率的影响

Effect of Holding Time in Mushy Zone on Nitrogen Content and Porosity of 201 Austenitic Stainless Steel

对低镍奥氏体不锈钢201在糊状区分别在氮气环境中保温0、5、10、15 min,探究保温时间对氮含量和气孔率的影响。结果表明:随着保温时间的增长,氮含量显著提高。糊状区保温可在避开凝固过程中的铁素体区,促进液相中的氮向奥氏体扩散。经过热力学分析,化学势差提供了氮从液相向奥氏体扩散驱动力。因此,糊状区保温是一种有效的不锈钢增氮方法,为生产高氮不锈钢提供了新思路。

The low nickel austenitic stainless steel 201 was held in mushy zone for 0, 5, 10, 15 min under nitrogen atmosphere. The effects of holding time on the nitrogen content and porosity were investigated. The results show that with the increase of holding time, the content of nitrogen significantly increases. Holding in the mushy zone can avoid ferrite region during solidification, and which can facilitate the diffusion of nitrogen from liquid into austenite. By thermodynamic analysis, the difference between chemical potential provides the driving force for nitrogen in liquid diffusing into austenite. So, holding in mushy zone is an effective way for increasing the nitrogen content in stainless steel, which can provide a new thought for the production of high nitrogen stainless steel.