时效工艺对Cu时效硬化钢组织及性能的影响  

Effect of aging process on microstructure and mechanical property of Cu age-hardening steel

作　　者：张正延[1] 王森才 柴锋[1] 罗小兵[1] 柴希阳[1] ZHANG Zhengyan;WANG Sencai;CHAI Feng;LUO Xiaobing;CHAI Xiyang(Institute for Structural Steels,Central Iron and Steel Research Institute Co.,Ltd.,Beijing 100081,China;China Institute of Atomic Energy,Beijing 102413,China)

机构地区：[1]钢铁研究总院有限公司工程用钢研究院,北京100081 [2]中国原子能科学研究院,北京102413

出　　处：《中国冶金》2025年第3期113-122,共10页China Metallurgy

基　　金：钢铁研究总院有限公司研发专项基金重点项目(事23G60340Z)。

摘　　要：为探索Cu时效硬化钢的时效特性,掌握最佳强韧性匹配的时效工艺,指导生产实践,利用扫描电镜(SEM)、高分辨透射电镜(HRTEM)、原子层析技术(APT)及Thermo-Calc计算软件对轧态、淬火态,以及不同时效工艺下Cu时效硬化钢的显微组织、冲击断口形貌以及纳米级富Cu相进行了表征、分析和计算,并考察和分析了不同热履历状态下试验钢的高强韧匹配性。结果表明,热轧态试验钢微观组织为粒状贝氏体,内含有大量大尺寸马氏体/奥氏体(M/A)岛,导致强度与低温韧性均不佳;淬火后试验钢可得到贝氏体/马氏体(贝/马)混合组织,钢的强韧性匹配较好,但塑性较差;淬火并经时效热处理后,随着时效温度的升高,试验钢的强度先升高后下降,在450℃以下处于欠时效状态,450℃达到峰值强度,但此时低温韧性最低,当温度超过450℃后,强度下降,韧性升高,温度达到650℃时,强度和韧性均降低。在620℃随着时效时间的延长,钢中贝/马亚结构及板条尺寸和富Cu相粒子尺寸均呈增大趋势,试验钢的强度逐渐降低,低温韧性逐渐升高,在620℃时效120 min的条件下能够获得优良的强韧性匹配。相对时效时间而言,时效温度对钢的性能影响更显著。To explore the aging characteristics of Cu age hardened steel,master the aging process that matches the best strength and toughness,and guide production practice,the microstructure,impact fracture morphology and nanoscale Cu-rich precipitates of tested steels with different thermal history were characterized using scanning electron microscopy(SEM),high-resolution transmission electron microscopy(HRTEM)and atomic chromatography(APT).And the precipitation kinetics of Cu-rich precipitates was calculated using Thermo-Calc calculation software.The high strength toughness matching of the tested steel under different thermal history states was also investigated and analyzed.The results show that the microstructure of the hot-rolled tested steel is granular bainite,containing a large number of large-sized M/A islands,resulting in poor strength and low-temperature toughness;after quenching,the mixed microstructure of bainite and martensite can be obtained,exhibiting good matching of strength and toughness,but poor plasticity;after quenching and aging heat treatment,the strength of the tested steel first increases and then decreases with the increase of aging temperature.After quenching and aging heat treatment,the strength of the tested steel first increases and then decreases with the increase of aging temperature.When the aging temperature is below 450℃,it is in an under aged state with lower strength.When the aging temperature reaches 450℃,the strength reaches its peak,but at this time,the low-temperature toughness is the lowest.When the temperature exceeds 450℃,the strength decreases and the toughness increases.When the temperature reaches 650℃,both the strength and toughness decrease.With the increase of aging time at 620℃,the size of substructure and lath as well as the size of Cu-rich precipitates in steel show increasing trend,resulting in a gradual decrease in the strength and and a gradual increase in toughness of the tested steel,and it is find that excellent strength toughness matching can be achieve

关 键 词：时效温度 时效时间 强韧性 微观组织 富Cu相 

分 类 号：TG142.1[一般工业技术—材料科学与工程]