SCM435钢的热压缩流变行为及组织演变  

Rheological behavior and microstructure evolution of SCM435 steel under thermal compression

作　　者：杜忠泽[1] 齐泽江 党雪 杨彤瑶 Du Zhongze;Qi Zejiang;Dang Xue;Yang Tongyao(School of Metallurgical Engineering,Xi'an University of Architecture and Technology,Xi'an Shaanxi 710055,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：《金属热处理》2024年第1期76-83,共8页Heat Treatment of Metals

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

摘　　要：采用Gleeble-3500热模拟试验机对SCM435钢在变形温度为750~1100℃、应变速率为0.1~20 s^(-1)条件下进行了热模拟压缩试验,基于钢的应力-应变曲线,分析了变形温度和变形速率对流变应力的影响,建立了应变量为0.6时SCM435钢的本构方程,并讨论了其组织演变规律及变形机制。结果表明,流变应力随着变形温度的升高而降低,随着应变速率的升高而增大。通过构建应变补偿型Arrhenius本构模型得到SCM435钢的热变形激活能(Q)约为344.564 kJ/mol,所建立本构模型的线性相关系数(R)约为0.9921,平均相对误差(AARE)约为4.39%。随着变形温度的升高,SCM435钢的变形机制从动态回复(DRV)转变为动态再结晶(DRX),且随应变速率的增大,DRX晶粒逐渐细化,说明升高变形温度及增大应变速率可以促进DRX行为的发生并抑制晶粒长大。通过EBSD结果分析得到SCM435钢在高温低应变速率(1100℃,0.1 s^(-1))条件下的平均取向差角最小,为1.27°,表明此时的位错密度最低。Thermal simulation compression test of SCM435 steel was carried out under the deformation temperature of 750⁃1100℃and the strain rate of 0.1⁃20 s^(-1) by Gleeble⁃3500 thermal simulation testing machine.Based on the stress⁃strain curves of the steel,the influence of deformation temperature and deformation rate on the flow stress was analyzed.The constitutive equation of SCM435 steel with strain of 0.6 was established,and the microstructure evolution and deformation mechanism were discussed.The results show that the flow stress decreases with the increase of deformation temperature and increases with the increase of strain rate.By constructing the strain⁃compensated Arrhenius constitutive model,the hot deformation activation energy(Q)of the SCM435 steel is about 344.564 kJ/mol,the linear correlation coefficient(R)and the average relative error(AARE)of the established constitutive model are about 0.9921 and 4.39%,respectively.With the increase of deformation temperature,the deformation mechanism of the SCM435 steel changes from dynamic recovery(DRV)to dynamic recrystallization(DRX),and with the increase of strain rate,DRX grains gradually refine,indicating that increasing deformation temperature and increasing strain rate can promote the occurrence of DRX behavior and inhibit grain growth.The average misorientation angle of the SCM435 steel under high temperature and low strain rate(1100℃,0.1 s^(-1))is the smallest,which is 1.27°,indicating that the dislocation density is the lowest.

关 键 词：SCM435冷镦钢 热压缩变形 本构方程 组织演变 

分 类 号：TG142[一般工业技术—材料科学与工程]