高应变速率对690合金热变形及可挤性的影响

The Effect of High Strain Rate on Hot Deformation Behavior and Extrusion Feasibility of 690 Alloy

摘要:

利用Gleelbe热模拟实验以及有限元分析了高应变速率对690合金热变形行为以及挤压可行性的影响,并根据实验和有限元结果进行挤压。结果表明：690合金的流变应力对应变速率均较敏感；大于10 s_-1 的高应变速率下,变形温升显著上升；再结晶晶粒尺寸在低应变速率下,随应变速率的升高而降低,高应变速率则随应变速率的增加而增大；挤压时,最大挤压力随着应变速率的上升先降低再升高；根据实验以及有限元计算结果,成功挤出了合格的690管材。

Abstract:

The effects of high strain rate on hot deformation behavior and extrusion feasibility were investigated by Gleeble thermal-simulation experiment and finite element method (FEM). The results show that the flow stress of 690 alloy is sensitive to the strain rate. The temperature rise in the alloy deformed with high strain rate (above 10 s_-1) is significant. The recrystallization grain size decreases with the increase of strain rate under low strain rate, however, that increase with the increase of strain rate under high strain rate. The maximum extrusion force presented earlier decrease and later increase trend with the increase of extrusion rate. The 690 pipe were succeesfully extruded according to the experiment and FEM results.