基于应变补偿及修正的Q460NH高强耐候钢本构方程

Constitutive equation of Q460NH high-strength weathering steel based on strain compensation and modification

为分析Q460NH钢的高温变形行为,利用Gleeble-3800热模拟实验机进行变形温度为600~900℃、应变速率为0.01~10 s^(-1)、变形量为60%的热压缩实验。将Zener-Hollomon参数与材料参数函数导入Arrhenius方程,建立了Q、A、n、α与真应变的本构关系的Arrhenius双曲正弦方程。考虑真应变对流动应力及700~800℃下实验误差的影响,对本构方程进行修正,用八阶多项式建立表示真应变和材料参数关系的数学模型,进一步建立了包含变形温度、应变速率及应变相关的Q460NH钢的高温变形本构方程。为了检验该本构方程计算所得理论值的有效性,对计算所得理论值和实验数据进行了对比及平均误差分析,相关系数r值为0.956、平均相对误差AARE值仅为7.23%。结果表明:修正后的本构方程计算得到的应力理论值和实验数据吻合较好,具有较高的准确性。

In order to analyze the high-temperature deformation behavior of Q460NH steel,the thermal compression experiment was carried out by Gleeble-3800 thermal simulation experimental machine with the experimental temperature of 600-900℃,the strain rate of 0.01-10 s^(-1) and the deformation amount of 60%,and the Arrhenius hyperbolic sine equation of the constitutive relationship between Q,A,n,αand true strain was established by importing the function of Zener-Hollomon parameters and material parameters into the Arrhenius equation.Then,considering the influence of true strain on flow stress and experimental error at 700-800℃,the constitutive equation was modified,and the mathematical model representing the relationship between true strain and material parameters was established by an eighth-order polynomial.Furthermore,the high-temperature deformation constitutive equation of Q460NH steel including deformation temperature,strain rate and strain correlation was established.In order to verify the validity of the theoretical values calculated by the constitutive equation,the calculated theoretical values and the experimental data were compared,and the average error was analyzed with the correlation coefficient r value of 0.956 and AARE value only of 7.23%.The results show that the theoretical stress value calculated by the modified constitutive equation is in good agreement with the experimental data and has a high accuracy.