核电用奥氏体不锈钢的动态再结晶行为

Dynamic recrystallization behavior of an austenitic stainless steel for nuclear power plants

利用Gleeble-1500D热模拟试验机对316LN奥氏体不锈钢进行单道次热压缩试验,分别设置变形温度为900-1200℃、应变速率为0.001-10 s^-1、真应变为0.1-0.9及试样的初始晶粒度为122-297μm之间,以研究热变形条件及初始晶粒度对316LN钢动态再结晶行为的影响.对试验数据进行处理,得到临界应变与峰值应变以及临界应力与峰值应力的比值分别为0.38和0.89,建立了动态再结晶动力学方程和晶粒尺寸演变方程.对建立的动态再结晶模型进行修正,将修正后的模型嵌入DEFORM-3D有限元模拟软件中进行计算,发现修正模型的模拟值和试验值符合较好,证明修正模型的准确性.

In order to study the effects of deformation conditions and initial grain size on the dynamic recrystallization behavior of316 LN austenitic stainless steel,single pass hot compression tests were conducted on a Gleeble-1500 D thermal-mechanical simulator with the deformation temperature of 900- 1200 ℃,the strain rate of 0. 001- 10 s^- 1,the true strain of 0. 1- 0. 9 and the initial grain size of 122- 297 μm. It is obtained that the ratio of critical strain to peak strain and the ratio of critical stress to peak stress are 0. 38 and 0. 89,respectively. A dynamic recrystallization kinetic model and a grain size evolution model were established based on experimental data. In addition,the developed models were modified for DEFORM-3D finite element simulation. It can be found that the simulated values by the modified model and experimental data agree well,indicating that the modified models have good accuracy.