核电用奥氏体不锈钢的动态再结晶行为

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.

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

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.