强韧X80管件钢的组织和力学性能  

Microstructure and properties of X80 pipe fitting steel

作　　者：张国春[1] 朱海宝[1] 武会宾[1] 唐荻[1] 冯书斐[1] 

机构地区：[1]北京科技大学高效轧制国家工程研究中心,北京100083

出　　处：《材料热处理学报》2011年第4期64-69,共6页Transactions of Materials and Heat Treatment

基　　金：国家"十一五"科技支撑计划资助项目(2006BAE03A06)

摘　　要：设计了一种新型低碳Mn-Nb-V(Ti)系低合金强韧X80级管件钢,对比研究了一次淬火回火、二次淬火回火6种不同工艺对其微观组织和力学性能的影响。结果表明:一次淬火X80管件钢抗拉强度最高,达695 MPa,屈服强度最低为526 MPa,冲击功48 J(-50℃);二次淬火加热温度为860℃+630℃×60 min回火的管件钢抗拉强度达652 MPa,屈服强度为585 MPa,冲击功达210 J(-50℃),具有最佳的综合力学性能。分析认为这归因于二次淬火温度在860℃时,组织主要由长条状的铁素体和细晶贝氏体、马氏体组成,以及在随后630℃回火后,块状M-A组元的分解、位错亚结构的回复软化、析出强化和板条边界钝化机制的综合作用。A new type of low-carbon low-alloy,Mn-Nb-V（Ti） X80 pipe fitting steel with high toughness is designed and the effects of different processes including double quenching-tempering suggested on microstructure and mechanical behavior of the steel were studied.The results show that the steel quenched at 930 ℃ presents the highest tensile strength of 695 MPa and the lowest yield strength of 526 MPa with the toughness of 48 J at-50 ℃.The pipe fittings steel after secondary quenching treatment at 860 ℃ and then tempering at 630 ℃ for 60 min exhibits the best mechanical behavior with the tensile strength of 652 MPa,the yield strength of 585 MPa and the toughness of 210 J at-50 ℃.It is suggested that this can be attributed to the microstructure consisting of rod-like ferrite,fine bainite and martensite when quenching at 860 ℃,as well as the combined effect of the decomposition of massive M-A,the recovery and softening of dislocation sub-structure,precipitation strengthening and the blunting of martensite lath boundary when tempering at 630 ℃.

关 键 词：管件钢 一次淬火 残留奥氏体 回火 

分 类 号：TG142.1[一般工业技术—材料科学与工程] TG156.1[金属学及工艺—金属材料]