TC1Mδ1·5mm钛板圆孔冷翻边极限与翘曲变形的研究

Research on hole-flanging limit and shape distortion with TC1Mδ1.5 Titanium alloy sheet

室温条件下采用有预制底孔的TC1Mδ1.5mm钛合金坯料进行圆孔翻边成形试验,结果表明,除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,卸载后翻边制件还会出现突缘平面翘曲、翻边孔口部椭圆化、口部收缩等形状翘曲现象,这些都造成钛合金薄板翻边零件无法满足尺寸和位置精度要求。在给出极限翻边系数的同时,对这种形状非轴对称化程度进行了定量描述,并解释了此类现象产生的原因。

The hole-flanging experiments were carried out at room temperature with TC1M titanium alloy sheets, and circular plates with thickness of 1.5mm and pre-determined-hole at the center of the specimen were used through out. In addition to the normal failure mode of lip cracking at the edges of flanged holes due to the pre-determined-hole is smaller than the limit, it was revealed that warp in periphery, elliptical change and shrink in lip of the flanged-hole occurred during unloading process. The finished shape with distortion would have great effects on the quality of hole-flanged parts. The limiting forming ratio is given and quantitative description of the level of the un-symmetrical change and explanation of the distinctive phenomena is presented.