时效温度对直接淬火Ni-Cr-Mo-V-Cu钢组织及性能的影响  

Effect of aging temperature on microstructure and mechanical properties of direct quenched Ni-Cr-Mo-V-Cu steel

作　　者：朱飞 罗小兵[1] 杨才福[1] 柴锋[1] 张正延[1] Zhu Fei;Luo Xiaobing;Yang Caifu;Chai Feng;Zhang Zhengyan(Institute of Structural Steels,Central Iron and Steel Research Institute,Beijing 100081,China)

机构地区：[1]钢铁研究总院工程用钢所,北京100081

出　　处：《金属热处理》2021年第11期54-64,共11页Heat Treatment of Metals

基　　金：国家重点研发计划(2017YFB0304501)。

摘　　要：利用OM、SEM、TEM及物理化学相等方法研究了时效温度变化对直接淬火Ni-Cr-Mo-V-Cu低合金钢组织及力学性能的影响,同时在具有最佳强韧性匹配的时效态试样中建立了屈服强度模型。Ni-Cr-Mo-V-Cu钢的直接淬火组织为马氏体和少量贝氏体组成的混合组织。直接淬火Ni-Cr-Mo-V-Cu钢在400~600℃范围内的不同温度时效处理后,其强度及维氏硬度表现出典型的欠时效阶段、峰时效阶段及过时效阶段。试验钢位错回复程度、MC及富铜粒子的析出、bcc铁基体中固溶元素的脱溶等因素随时效温度的变化是时效态试验钢表现出上述3个阶段的重要原因。时效态试验钢的断后伸长率大体随时效温度的提高而改善。过时效态试验钢的-20℃冲击性能则随着时效温度的升高而提高。直接淬火试验钢在600℃时效处理时获得优越的强韧性匹配,MC及富铜粒子所提供的总析出强化增量约为240 MPa。Effect of aging temperature on microstructure and mechanical properties of the direct quenched Ni-Cr-Mo-V-Cu low alloy steel was investigated by means of OM,SEM,TEM,physicochemical phase analysis and so on.At the same time,the yield strength model was established in the aged specimen with the best strength toughness matching.Microstructure of direct quenched Ni-Cr-Mo-V-Cu steel consists of martensite and a small amount of bainite.When the direct quenched Ni-Cr-Mo-V-Cu steel is aged in the range of 400℃to 600℃respectively,strength and Vickers hardness of the tested steel show typical under-aged state,peaking-aged state and over-aged state.The change of dislocation recovery,precipitation of MC and Cu-rich particles,desolvation of solid solution elements in bcc iron matrix and so on with aging temperature is responsible for the aged specimens showing the above three states.Elongation after fracture of the aged specimen generally improves with the increase of ageing temperature.Impact property at-20℃of the over-aged specimen increases with the increase of ageing temperature.The direct quenched specimen aged at 600℃shows superior combination of strength and toughness,and precipitating strengthening increment caused by MC and Cu-rich particles is about 240 MPa.

关 键 词：含Cu低合金钢 直接淬火 时效 强化机制 

分 类 号：TG156.5[金属学及工艺—热处理]