モーション制御を活用したTi-6Al-4V合金板の温間プレス成形技術の開発

抄録

In general, Ti-6Al-4V alloy sheets are formed by incremental press forming in the temperature range between 600 and 900 ℃. In this temperature range, the ductility of Ti-6Al-4V alloy is improved. Because of the low ductility of Ti-6Al-4V alloy at temperatures between room temperature and 600 ℃, fracture easily occurs during press forming. Hence, a method of press forming of Ti-6Al-4V alloy sheets between room temperature and 300 ℃ was developed. In this method, the punch motion and blank holding force were applied separately until the maximum punch load was reached to prevent fracture at the punch shoulder. The drawing process was carried out from the maximum punch load until finish forming to prevent fracture at the end of the flange. In addition, by applying the developed method, we were able to prevent the decrease in thickness at the punch shoulder, compared with the case of press forming. As a result, warm press forming of Ti-6Al-4V alloy sheets at 300 ℃ was achieved by applying the developed method in experiments and finite element analysis.