摘要
高氮铬锰奥氏体不锈钢有着极为广泛的应用前景,然而氮含量对其相转变的影响尚不十分清晰。设计并冶炼了氮质量分数为0.02%~1.20%的试验钢,对各钢的平衡相转变进行了热力学计算,对δ铁素体和Cr2N的形貌进行了观察。结果表明,钢中δ铁素体的最大析出量随着氮含量的升高而降低,当氮质量分数超过1.05%后,无δ铁素体析出。获得了试验钢加热时δ铁素体的析出温度与氮含量的关系式。随着氮含量的升高,试验钢在冷却时Cr2N的析出温度逐渐升高,并获得了其定量关系式。在GN04钢中,1 200℃等温2h后的δ铁素体主要沿三叉晶界分布。Cr2N析出优先在晶界形成,然后朝着晶内发展。在相同等温条件下,试验钢中Cr2N的析出量随着氮含量的升高而增大,且层片间距随之减小。
High nitrogen nickel-free austenitic stainless steels have wide application prospects in many fields.However,the effects of nitrogen mass fraction on phase transitions are still unclear yet.High nitrogen nickel-free austenitic stainless steels with nitrogen mass fraction from 0.02%to 1.20% were designed and melted.And the thermodynamic calculation of equilibrium phase transition of steels was carried out,the morphology of δ ferrite and Cr2 N was observed.The results showed that the maximum precipitation ofδferrite was decreased with nitrogen mass fraction increase,but when nitrogen mass fraction beyond 1.05%,there was no δ ferrite found.The relations between the precipitation temperature of δ ferrite and nitrogen mass fraction during the steel heating process were obtained.With the increase of nitrogen mass fraction,the precipitation temperature of Cr2 N when steels were cooling increased gradually,and its quantitative relationship was obtained.In GN04 steel,the δ ferrite after 1 200 ℃ is othermal heat treatment in 2 hwas mainly distributed along the trigeminal grain boundary.The precipitation of Cr2 N was formed firstly on grain boundary and then spread in crystal.It also increased with nitrogen mass fraction increase in the same isothermal heat treatment,but layer spacing decreased.
作者
宁小智
邢长军
雍岐龙
翁建寅
NING Xiao-zhi;XING Chang-jun;YONG Qi-longl;WENG Jian-yin(Department for Structural Materials,Central Iron and Steel Research Institute,Beijing 100081,China;Technology Center,FIYTA(Group)Co.,Ltd.,Shenzhen 518057,Guangdong,China)
出处
《中国冶金》
CAS
北大核心
2019年第12期51-54,74,共5页
China Metallurgy
关键词
氮含量
高氮钢
铁素体
氮化物
nitrogen content
high-nitrogen steel
ferrite
nitride