TC2Mδ1.5钛板翻边成形极限及非轴对称畸变的研究

Investigation on Formability and Nonaxisymmetric Distortions During Hole-Flanging of TC2Mδ1.5 Titanium Alloy Sheet

为研究各向异性对圆孔翻边成形的影响,用TC2Mδ1.5 mm钛合金圆板料在室温及600℃高温条件下分别进行了圆孔翻边试验.结果发现,除翻边底孔尺寸小于极限值时在唇口边缘发生破裂的正常失效方式之外,冷翻边制件卸载后发生了凸缘平面翘曲、翻边孔口部椭圆化、唇口边缘高度不一致、壁厚分布不均匀等非轴对称畸变现象.高温热翻边成形有效地提高了成形极限,并消除了凸缘平面翘曲和口部椭圆化,但口部高差以及壁厚不均等现象依然存在.本文在给出极限翻边系数结论的同时,对非轴对称畸变现象进行了定量描述、分析与解释.

To make sure of the effect of anisotropy on the shape/size precision of workpiece, a series of hole-flanging experiments were carried out at room temperature and 600 ℃ ,with 1.5 mm-thick TC2M titanium alloy sheet as specimens on which pre-drilled holes were provided at the center. It was found that there are some nonaxisymmetric distortions such as peripheral flange warpage, elliptical opening shape, uneven lip surface of the finished hole and ununiformly distributed wall thickness after unloading in addition to the normal rupture at lip edge when the initial hole diameter is smaller than the minimum size. The flanging process at high temperature can improve effectively formability, get rid of peripheral warpage and elliptical opening,but the lip surface and wall thickness can not be evened yet. The ultimate hole-flanging coefficient is given in two different states, while the nonaxisymmetric distortions are quantitatively described and analyzed.