B55SiCr钢的高温流变行为及动态再结晶临界条件  

High-temperature flow behavior and critical conditions of dynamic recrystallization of B55SiCr steel

作　　者：王庆娟[1] 张昭 杜忠泽[1] 齐泽江 杨彤瑶 WANG Qingjuan;ZHANG Zhao;DU Zhongze;QI Zejiang;YANG Tongyao(School of Metallurgy Engineering,Xi'an University of Architecture and Technology,Xi'an 710055,Shaanxi,China)

机构地区：[1]西安建筑科技大学冶金工程学院,陕西西安710055

出　　处：《钢铁》2024年第4期168-178,共11页Iron and Steel

基　　金：国家自然科学基金资助项目(52174371);陕西省科技厅企业联合基金资助项目(2021JLM-33)。

摘　　要：B55SiCr钢主要用于制作汽车悬架簧、阀门簧钢丝等,对汽车平稳性、安全性起着举足轻重的作用,对组织性能有较高的要求。以B55SiCr钢为研究对象,在变形温度和应变速率为800~1050℃和0.1~20 s^(-1)的范围内进行了热压缩试验,并基于Zener-Hollomon参数,采用线性拟合方法构建双曲正弦Arrhenius本构模型。研究发现,B55SiCr钢的流变应力随变形温度的升高而减小,随应变速率的增加而增大,其热变形激活能(Q)为317 kJ/mol左右。通过本构模型得到流变应力预测结果与试验结果的线性相关系数(R)和平均绝对相对误差(|δ|)分别为0.99215和3.70%。绘制了加工硬化率曲线,并根据应力应变曲线与加工硬化率曲线确定了B55SiCr钢发生动态再结晶(DRX)的临界应力与应变,得到临界条件与Z参数均呈指数关系的结论。分析了B55SiCr钢的显微组织,发现在低温热变形条件下,出现混晶组织,显微组织呈非均匀状态,在高温热变形条件下,显微组织为均匀的等轴晶;分别绘制了不同变形条件下的KAM图和局部取向差分布图,发现随着应变速率的降低及变形温度的升高,位错密度显著降低,DRX更加完全且晶粒逐渐粗化,变形条件为1050℃/0.1 s^(-1)比850℃/10 s^(-1)的HAGBs含量增加了13.51%。在变形条件为1050℃/0.1 s^(-1)时,材料发生完全再结晶,晶粒粗化,此变形条件下B55SiCr钢具有良好的热加工性;随着应变速率的增加,晶粒细化。B55SiCr steel is mainly used to make automobile suspension springs,valve spring steel wires,etc.It plays a pivotal role in the stability and safety of automobiles,and has high requirements for organizational performance.Taking B55SiCr steel as the research object,thermal compression experiments were carried out in the range of deformation temperature and strain rate of 800-1050℃and 0.1-20 s^(-1),and based on the Zener-Hollomon parameters,a linear fitting method was used to construct a double Curved sine Arrhenius constitutive model.It is found that the flow stress of B55SiCr steel decreases with the increase of deformation temperature and increases with the increase of strain rate,and its thermal deformation activation energy(Q)is about 317 kJ/mol.The linear correlation coefficient(R)and the average absolute relative error(|δ|)of the flow stress prediction results and the test results obtained through the constitutive model are 0.99215 and 3.70%,respectively.The work hardening rate curve was plotted.According to the stress-strain curve and the work hardening rate curve,the critical stress and strain for dynamic recrystallization(DRX)of B55SiCr steel were determined,and the critical condition and Z parameters are all in an exponential relationship.The microstructure of B55SiCr steel was analyzed,and it was found that under the condition of low temperature thermal deformation,mixed crystal structure appeared,and the microstructure was in a non-uniform state,and under the condition of high temperature thermal deformation,the microstructure was uniform equiaxed crystal;the KAM diagrams and local orientation difference distribution diagrams under different deformation conditions were drawn respectively.It was found that with the decrease of strain rate and the increase of deformation temperature,the dislocation density significantly decreased,the DRX became more complete and the grains gradually coarsened.The deformation conditions The HAGBs content at 1050℃/0.1 s^(-1) increased by 13.51%compared with 850℃/10 s

关 键 词：B55SiCr钢 本构模型 变形机制 动态再结晶 临界条件 

分 类 号：TG142.1[一般工业技术—材料科学与工程]