应变速率和应力三轴度对316LN钢强度的影响

Influence of strain rate and stress triaxiality on strength of steel 316LN

为了获得应变速率和应力三轴度对316LN钢强度的影响,在Gleeble-1500D热模拟实验机上进行了温度为1050℃的热拉伸实验。对于光滑试样,应变速率分别为0.005,0.05,0.5和1 s-1。对于缺口试样,应变速率设为0.5 s-1,缺口半径分别设为0.5,1,2和4 mm。结果表明,随应变速率和应力三轴度的增加,屈服强度和抗拉强度增加,屈强比减小,裂纹不易萌生。通过回归分析,分别建立了强度指标与应变速率和应力三轴度之间的数学模型,并通过敏感性分析得到:随应变速率增加和应力三轴度减小,应变速率和应力三轴度对强度的影响变小。

To obtain the influence of strain rate and stress triaxiality on strength of steel 316LN, the thermal tensile tests of steel 316LN were conducted by Gleeble- 1500D thermal simulator at 1050℃. For the smooth specimens, the strain rates were set as 0. 005, 0.05, 0. 5 and 1 s-1 respectively. However, for the notched specimens, the strain rate was set as 0.5 s-1 , and the notch- radius were set as 0.5, 1, 2 and 4 mm respectively. The results show that with the increase of strain rate and stress triaxiality, the yield strength and tensile strength increase, and the yield - tensile ratio decreases. Thus, the crack is hard to produce. Further- more, the models between strength index and strain rates, stress triaxialities were established by regression analysis respectively. At last, the sensitivity analysis shows that with the increase of strain rate and the decrease of stress triaxiality, the influences of strain rate and stress triaxiality on strength decrease.