摘要
通过向传统矿用圆环链钢23MnNiCrMo54中加入质量分数为0.29%的V以提高钢的综合性能,检测了不同回火温度下含V试验钢的各项力学性能,利用SEM、TEM和物理化学相分析等方法对试验钢的基体组织和析出相进行了表征,分析了试验钢的强韧化机制。结果表明,含0.29%V试验钢在不同温度回火后的强度均有大幅提升,随回火温度升高,含V试验钢的强度变化经历3个阶段:强度先是下降,当回火温度达到500℃时开始出现强度平台,继续提高回火温度至600℃后,强度又开始下降。结合物理化学相分析和TEM表征,认为强度平台的出现是因为大量析出的纳米级碟片状VC颗粒带来沉淀强化作用;-20℃冲击吸收能量随回火温度变化曲线呈“W”型,Fe3C在晶界析出和杂质元素的偏聚是导致韧性低谷的原因。
In order to improve the comprehensive properties of the traditional mining ring chain steel,a modified 23MnNiCrMo54 steel with 0.29 wt.%V addition was developed.The mechanical properties and microstructures of the test steels after quenching and tempering at different temperatures(200,400,500,550,600 and 650℃)were analyzed and characterized by uniaxial tensile tests,scanning electron microscope(SEM),transmission electron microscopy(TEM),X-ray diffraction(XRD),physicochemical phase analysis and so on.The results show that compared with the V-free steel,the strength of the test steel with 0.29%V after tempering at different temperatures is greatly improved,and the maximum yield strength increment is about 299MPa when tempered at 650℃.With the increase of tempering temperature,the strength change of the test steel can be divided into three stages:the strength first decreases,then a strength plateau appears at the temperatures ranging from 500 to 600℃,and with the tempering temperature further increasing,the strength begins to decrease again.Combined with physicochemical phase analysis and TEM characterization,it is believed that the emergence of the strength plateau is due to the precipitation strengthening effect of a large number of nano-scale disc-like VC particles precipitated at above 500℃,which offset the matrix softening caused by the reduction of dislocation density.The change curve of impact energy at-20℃with tempering temperature exhibits a“W”shape.The lower impact absorbed energy at 400℃is caused by the first type of temper brittleness resulted from the precipitation of long and needle-like Fe3C at the grain boundaries.When tempered at 600℃,the toughness decreases again,which may be caused by the second type of temper brittleness because of the segregation of impurity elements at grain boundaries.
作者
王昕
梁小凯
童帅
朱秀光
孙新军
WANG Xin;LIANG Xiaokai;TONG Shuai;ZHU Xiuguang;SUN Xinjun(Institute of Structural Steels,Central Iron and Steel Research Institute Co.,Ltd.,Beijing 100081,China;Technology Center of China Coal Zhangjiakou Coal Mining Machinery Co.,Ltd.,Zhangjiakou 076250,Hebei,China)
出处
《钢铁研究学报》
CAS
CSCD
北大核心
2023年第4期471-481,共11页
Journal of Iron and Steel Research
基金
河北省科技重大专项资助项目(21281002Z)
国家重点研发计划资助项目(2017YFB0305100)。
关键词
低合金马氏体钢
VC析出
回火温度
强化增量
力学性能
low alloyed martensite steel
VC precipitation
tempering temperature
strengthening increment
mechanical property
