N含量对29Cr铸造超级双相不锈钢组织及性能的影响  

EFFECTS OF N CONTENT ON MICROSTRUCTURE AND PROPERTIES OF 29Cr CASTING SUPER DUPLEX STAINLESS STEEL

作　　者：向红亮[1] 黄伟林[1] 刘东[1] 何福善[1] 

机构地区：[1]福州大学机械工程及自动化学院,福州350108

出　　处：《金属学报》2010年第3期304-310,共7页Acta Metallurgica Sinica

基　　金：科技部科技人员服务企业项目2009GJC40018;福建省青年人才创新基金项目2008F3061;福州大学科技发展基金项目2008-XQ-16资助~~

摘　　要：制备了含N量分别为0.11%,0.26%和0.42%的29Cr铸造超级双相不锈钢,利用XRD,SEM,EDS,电化学工作站和XPS研究了含N量对双相不锈钢显微组织、力学性能和耐蚀性的影响.结果表明:N能增加双相不锈钢中奥氏体含量,并且有φ(γ)=60×ω(N)+21.97的线性关系;由于N具有固溶强化和降低(Mn,Cr)S夹杂粒子的作用,能有效提高材料的抗拉强度和延伸率,两者与含N量的关系分别为σ_b=318.33×ω(N)+626.3和δ=60×ω(N)+10.83.在海水腐蚀过程中,铁素体优先腐蚀.N使Cr的分布均匀化,并参与腐蚀反应生成NH_4^+和NO_3^-,促进钝化膜的再钝化;Mo可以生成MoO_4^(2-).提高钝化膜的稳定性,增强耐蚀性.钢中含N量越高,腐蚀电流密度越低,耐蚀性越好.Microstructures,mechanical properties and corrosion resistances of 29Cr super duplex stainless steel（SDSS） with N contents of 0.11%,0.26%and 0.42%have been investigated by XRD, SEM,EDS,electrochemical workstation and XPS.The results show that with increasing N content the distribution of Cr becomes homogeneous,the amount ofγphase increases according to a linear relationship ofφ（γ） = 60×w（N）＋21.97,and the tensile strength and elongation of the steel are improved according to the relationships ofσb= 318.33×（w（N））^1/2＋626.3 andδ= 60×w（N）＋10.83, respectively.due to the roles of solution strengthening and reducing（Mn,Cr）S precipitation.In the process of seawater corrosion,αphase in the steel would be corroded first,N can form NH4^＋ and NO3^- to promote the re-passivation effect of passive film;and Mo can form MoO4^2- to improve the stability of passivated layer and strengthen the corrosion resistance of the steel.The higher the N content,the lower the corrosion current density and the better the corrosion resistance for the steel.

关 键 词：29Cr超级双相不锈钢 N含量 抗拉强度 延伸率 极化曲线 钝化膜 

分 类 号：TG172.8[金属学及工艺—金属表面处理]