TC18钛合金热锻成形换热系数实验研究

Research on heat transfer coefficient in hot forging of TC18 titanium alloy

在TC18钛合金热锻成形过程中,锻件与空气、锻件与模具之间的换热系数对热锻成形过程具有显著的影响。为了精确地测定不同条件下的锻件与空气、锻件与模具之间的换热系数,基于工艺实验并结合Deform-3D有限元分析方法,通过热传导反问题法,测定了TC18钛合金在不同条件下对应的换热系数。结果表明:在加热过程中,TC18钛合金与空气的换热系数在0.10~0.30 N·(s·mm·℃)^(-1)的范围内变化;在冷却过程中,试样与空气的换热系数在0.02~0.10 N·(s·mm·℃)^(-1)范围内变化;试样与模具之间的换热系数受接触面的条件影响较大,无介质、玻璃润滑剂的界面的峰值换热系数较大,约为4.5 N·(s·mm·℃)^(-1),而在保温棉、玻璃纤维布、新型复合布界面接触条件下的换热系数较小,约在0.4~0.5 N·(s·mm·℃)^(-1)附近。

In the hot forging process of TC18 titanium alloy,the heat transfer coefficients between forgings and air,forgings and mold have significant impact on the hot forging process.Therefore,in order to accurately measure the heat transfer coefficients between forgings and air,forgings and mold under different process conditions,the corresponding heat transfer coefficients of TC18 titanium alloy under different conditions were studied by the heat conduction inverse problem method based on process experiments combined with Deform-3D finite element analysis.The results show that during the heating process,the heat transfer coefficient between TC18 titanium alloy and air changes in the range of 0.1-0.3 N·(s·mm·℃)^(-1),and during the cooling process,the heat transfer coefficient between sample and air changes in the range of 0.02-0.10 N·(s·mm·℃)^(-1).However,the heat transfer coefficient between sample and mold is greatly affected by the conditions of contact surface.The peak heat transfer coefficient of interface without medium and glass lubricant is relatively large,about 4.5 N·(s·mm·℃)^(-1),while the heat transfer coefficients of interface with insulating cotton,glass fiber cloth and new composite cloth are small,around 0.4-0.5 N·(s·mm·℃)^(-1).