Thermal-mechanical and springback behavior of dual-phase steel at warm temperatures  

温热成形下双相钢板热-力学性能与回弹行为

作　　者：LIN Qi-quan WANG Zhen-zhu DONG Wen-zheng BU Gen HUANG Jin-shan 林启权;王镇柱;董文正;卜根;黄巾珊(School of Mechanical Engineering,Xiangtan University,Xiangtan 411105,China;Department of Mechanical and Systems Engineering,Gifu University,Yanagido 501-1193,Japan)

机构地区：[1]School of Mechanical Engineering,Xiangtan University,Xiangtan 411105,China [2]Department of Mechanical and Systems Engineering,Gifu University,Yanagido 501-1193,Japan

出　　处：《Journal of Central South University》2022年第6期1895-1905,共11页中南大学学报（英文版）

基　　金：Projects(2020JJ4578, 2019JJ50604) supported by the Natural Science Foundation of Hunan Province,China;Project(19A499) supported by the Key Program of the Scientific Research Foundation of the Education Department of Hunan Province,China。

摘　　要：For non-quenchable dual-phase(DP)steel sheet,the warm forming process can effectively reduce the amount of springback,and the mechanical parameters that influence its elastic and inelastic recovery to decrease exhibit a strong temperature dependence,especially under cyclic loading conditions.In this paper,the monotonic and cyclic loading tests of DP980 steel sheets are conducted at the temperatures ranging from 25℃ to 500℃.The temperature-dependent flow stress,nonlinear elastic recovery,and Bauschinger effect are investigated.The results demonstrate that both the elastic modulus and Bauschinger effect show an exponential law with pre-strain,and decrease with the increase of forming temperature,while there will be an abnormal phenomenon of rebound due to the influence of dynamic strain aging effect.Meanwhile,a linear relationship between the Bauschinger effect and inelastic strain is observed at various temperatures,and the weight of the Bauschinger effect in the total strain reduces with temperature increasing,which indicates that the springback is dominated by linear elastic recovery.Furthermore,the U-draw bending tests are carried out to clarify the influence of Vickers hardness distribution and martensite size effect on the springback behavior.对于不可淬火的双相钢(DP钢),温热成形技术可以显著降低其回弹量,引起其弹性和非弹性回复降低的力学参数与温度有强烈的相关性,尤其是在循环变形条件下。本文对DP980钢板在25~500℃温度下进行了单轴加载和循环加载-卸载试验,研究温度相关流变应力、非线性弹性回复和包辛格效应的演化规律。结果表明,DP980钢板的弹性模量和包辛格效应均随预应变的增大而呈指数型演化,并随成形温度的升高而减小。由于动态应变时效效应的影响,该演化行为会出现反弹现象。同时,在不同温度下,包辛格效应与非弹性应变呈线性关系演化,且包辛格效应在总应变中的权重随着温度的升高而降低,说明在较高的温度下回弹逐渐以线弹性回复为主。此外,还进行了U形拉深-弯曲的工艺试验,以阐明维氏硬度分布和马氏体尺寸效应对回弹行为的影响。

关 键 词：warm forming dual-phase steel springback behavior nonlinear elastic recovery Bauschinger effect 

分 类 号：TG142.1[一般工业技术—材料科学与工程]