冷速对热连轧钛合金棒材残余应力的影响

Effect of Cooling Rate On Residual Stress of Hot-Rolled Titanium Alloy Rod

采用ABAQUS有限元分析软件,在钛合金棒材八道次连轧的基础上,对轧后轧件冷却过程进行热力耦合分析,研究了冷却速率对轧后棒材应力的影响。结果表明,自然水冷和强制水冷时,随着温度变化有较大残余应力产生。自然空冷和强制空冷时,残余应力随温度变化缓慢上升,尤其以自然空冷时应力上升幅度最小,棒材表面应力大约136 MPa,中心应力大约35 MPa。钛合金棒材冷却时最好采用空冷或更慢冷的方式,以降低残余应力。

Finite element analysis software ABAQUS was applied in the coupled analysis between temperature and stress during cooling process after rolling for titanium alloy rod, based on eight-pass continuous rolling process. The effect of the cooling rate on residual stress of rolled rod was studied. The results show that large residual stress arises with the change of the temperature under natural water-cooling and compulsory water-cooling process. However, the residual stress rises slowly with the variation of the temperature under natural air-cooling and forced air-cooling process. Especially, its change range is least under air-cooling process. The surface stress of the rod is about 136 MPa, and the center stress is about 35 MPa. Therefore, air cooling or cooling more slowly is a better way for titanium alloy rod to decrease residual stress.