热处理对25CrMoNiVNbTi钢高温拉伸性能的影响  

Effect of heat treatment on high-temperature tensile properties of 25CrMoNiVNbTi steel

作　　者：陈孝文[1] 李仁仆 张德芬[1] 唐瑜[1] 李婷[1] 朱亚[1] 

机构地区：[1]西南石油大学材料科学与工程学院,四川成都610500

出　　处：《金属热处理》2016年第11期144-148,共5页Heat Treatment of Metals

基　　金：住房和城乡建设部科学技术项目(2014-K4-036);油气藏地质及开发工程重点实验室开放基金课题(PLN1416)

摘　　要：研究了淬火温度对25CrMoNiVNbTi钢的高温拉伸性能和组织的影响。结果表明：在900-1100℃温度范围内,随着淬火温度的升高,25CrMoNiVNbTi钢在600℃的高温拉伸性能先增加后降低,本试验条件下的最佳热处理工艺为1000℃淬火30 min＋620℃回火2 h,经该工艺处理后该钢在600℃下拉伸时其屈服强度和抗拉强度分别达到974 MPa及1046 MPa,洛氏硬度为40.5 HRC,显微组织为回火索氏体、贝氏体、碳化物和少量的残留奥氏体,而且钢的晶粒细小,位错密度高,大大提高了该钢在高温下的力学性能。扫描电镜观察结果表明该钢在高温下拉伸后的断口为韧性断裂。The influence of quenching temperature on high-temperature tensile properties and microstructure of 25 CrMoNiVNbTi steel was studied. The results reveal that with the quenching temperature increasing,the tensile properties of the 25 CrMoNiVNbTi steel at 600 ℃increases firstly and then decreases when quenched in the range of 900 - 1100 ℃. The optimum heat treatment process is quenching at 1100 ℃for 30 min and tempering at 620 ℃ for 2 h in this experimental conditions. After treated by this process and tested at 600 ℃,the tensile yield strength and tensile strength of the samples reach to 974 MPa and 1046 MPa,respectively,the Rockwell hardness reaches to40. 5 HRC. Moreover,microstructure of the samples is composed of tempered sorbite,bainite,carbides and a small amount of retained austenite and the grains is fine with high dislocation density in micro-scale. Owning to this microstructure,the mechanical properties of the steel are improved significantly at high temperatures. The fracture observation results show that the tensile fracture of the steel is ductile at high temperature.

关 键 词：25CrMoNiVNbTi钢 热处理 高温拉伸性能 组织 

分 类 号：TU511.3[建筑科学—建筑技术科学]