核电用316LN奥氏体不锈钢延性断裂阈值研究

Study on Ductile Fracture Threshold of 316LN Austenitic Stainless Steel for Nuclear Power

在Gleeble-1500D模拟机上对核电用316LN奥氏体不锈钢的热拉伸行为进行了研究,获得了钢在变形温度900~1200℃、应变速率0.01~1 s-1条件下拉伸变形的真应力-真应变曲线。通过Deform-3D有限元软件模拟了热拉伸过程,利用迭代法对试样颈缩后对应的真应力-真应变曲线进行修正。对试样颈缩前塑性变形部分对应的真应力-真应变数据拟合处理,得到了不同变形条件下316LN奥氏体不锈钢的硬化指数。将修正后的真应力-真应变曲线和计算得到的硬化指数导入Deform-3D软件中模拟热拉伸过程,计算得到了316LN奥氏体不锈钢热变形时的断裂阈值。

Hot tensile behaviors of 316LN austenitic stainless steel for nuclear power were studied on a Gleeble-1500D simulator. True stress true strain curves of tensile deformation were obtained at deformation temperatures of 900-1200 ℃ under strain rates of 0.01-1 s-1. Hot tensile process was simulated by Deform-3D finite element software. The true stress-true strain curves after necking were modified by using iterative method. Fitting processing of true stress-true strain data for plastic deformation before specimen necking was carried out. The hardening exponents of 316LN austenitic stainless steel under different deformation conditions were obtained. The modified true stress-true strain curves and the hardening exponents were embedded into Deform-3D software to simulate hot tensile process. And the fracture threshold values of 316LN austenitic stainless steel were calculated and obtained.