摘要
在变形温度为1123~1423 K和应变速率为0.01~10 s-1条件下,对DP590高强钢进行高温热拉伸试验,得到其真应力-真应变曲线,分析了温度和应变速率对DP590高强钢热变形时流动应力的影响。结果表明,当应变量一定时,流动应力随应变速率的升高和温度的降低而增大。基于热拉伸试验数据,通过线性回归分别确定了在峰值应力下DP590高强钢的高温材料常数:应变硬化指数n=3.194,热变形激活能Q=508.29 k J·mol-1,α=0.0153和A=2.126×1017s-1。构建了DP590高强钢的Arrhenius双曲正弦本构关系,与试验值相比,模型的最大误差为7.8%,最小误差为0.18%。根据DMM动态材料模型建立了DP590高强钢在应变为0.3条件下的热加工图,确定了DP590高强钢的适宜热成形区为:应变速率为0.01~0.1 s-1,变形温度为1250~1375 K。
The isothermal tensile tests of high-strength steel DP590 were carried out at temperature ranges of 1123-1423 K and strain rates of 0. 01-10 s-1. Then,the true stress-strain curves were plotted to analyze the effects of temperature and strain rate on the flow behavior of thermal deformation for high-strength steel DP590. The results show that the flow stress increases with decreasing of temperature and increasing of strain rate. Based on the isothermal tensile test data,the high temperature material constants are obtained through multiple linear regression analysis with the strain hardening coefficient n = 3. 194,thermal activation energy Q = 508. 29 k J · mol-1,α =0. 0153 and A = 2. 126 × 1017s-1. Therefore,the hyperbolic sine Arrhenius constitutive model for high-strength steel DP590 was established. Compared with the experimental results,the maximum error is 7. 8%,and the minimum error is 0. 18%. Based on the dynamic material model（DMM）,the hot processing map of high-strength steel DP590 under the strain of 0. 3 was constructed,and the suitable hot deformation range of high-strength steel DP590 is determined as the strain rates of 0. 01-0. 1 s-1and the deformation temperate of 1250-1375 K.
出处
《锻压技术》
CAS
CSCD
北大核心
2017年第1期121-125,共5页
Forging & Stamping Technology
基金
重庆市教委2015年度科学技术研究项目(KJ1505301)
关键词
DP590高强钢
热成形
流动应力
本构关系
热加工图
high-strength steel DP590
hot deformation
flow stress
constitutive relationship
hot processing map
