合金钢A517Q加热小变形下的应力应变模型

Strain-Stress Model for A517Q in the Case of Small Deformation in Heating Process

为了在有限元分析中精确计算钢坯加热过程中的应力分布情况,建立了描述A517Q钢不同温度下真应力真应变曲线的数学模型.将拉伸实验与膨胀实验所得数据结合处理,得到了不同温度下的机械应变对应的真应力曲线,排除了热膨胀与材料氧化的影响.建立该模型仅需5个关键参数,对于无明显屈服平台且应力随应变持续增长的应力应变曲线具有良好的描述精度.将通过处理A517Q钢拉伸实验数据获得的5个关键参数拟合为关于温度的函数,代入已建立的应力应变数学模型中,实现了对不同温度下材料力学性能的准确预测.将本模型植入有限元,模拟得到了钢坯加热过程中的应力分布,可为优化加热工艺提供参考.

In order to use finite element to accurately calculate the stress distribution for A517Q slab in the heating process, a mathematical model was proposed to represent the true strain-stress curves for AS17Q steel at varying temperatures. Experimental data of tensile and expansion tests were applied to obtain the true stress versus mechanical strain at different temperatures, so as to exclude the influence of thermal ex- pansion and oxidization. The mathematical model was based on five key parameters which could be ob- tained from the true strain-stress curve. This model was adaptive to simulating monotonically strain-stress curves without a yield plateau. In application, these five parameters were regressed as the functions of temperature, so that the strain-stress model at any temperature can be obtained conveniently. The model was further embedded in finite element code to analyse the stress distribution of AS17Q slab in the heating process.