扩孔变形模式对筒形件成形的影响规律

Influence laws of reaming deformation modes on forming of cylindrical parts

采用数值模拟方法分析了筒形件自由锻马杠扩孔成形过程和热辗扩成形过程,对比分析了两种变形模式对筒形件变形规律的影响。研究结果表明:相同壁厚锻比的条件下,局部加载间歇变形模式的马杠扩孔成形的筒形件横剖面上等效应变沿周向周期性分布,其大小沿径向从内到外逐渐降低;而局部加载连续变形模式的热辗扩成形的筒形件横剖面上等效应变沿周向均匀分布,其大小在外径处最高,内径处次之,壁厚中心最低。对比发现:两种变形模式中壁厚中心的等效应变值相当,且热辗扩成形的筒形件壁厚中心的等效应变略大。结合热辗扩成形试验结果发现:在相同壁厚锻比的条件下,热辗扩成形工艺可以替代马杠扩孔成形工艺来成形筒形件,在保证环坯充分锻透的前提下,获得变形均匀的筒形件。

The ring forging process and the hot ring rolling process in the free forging of a cylindrical part were simulated by the numerical simulation method,and the influences of the two deformation modes on the forming laws of the cylindrical part were analyzed.The research results show that under the condition of the same wall thickness forging ratio,the equivalent strain in the cross section of the cylindrical part formed by ring forging with the local loading intermittent deformation mode is periodically distributed along the circumferential direction,and its value gradually decreases from inner to outer along the radial direction.However,the equivalent strain in the cross section of the cylindrical part formed by hot ring rolling with the local loading continuous deformation mode is uniformly distributed along the circumferential direction,and its value is the highest at the outer diameter,second at the inner diameter,and the lowest at the center of wall thickness.By comparison,it is found that the equivalent strain values at the center of wall thickness are comparable in the two deformation modes,and the equivalent strain at the center of wall thickness formed by hot ring rolling is slightly larger.Combined with the experimental results of hot ring rolling,the results show that the hot ring rolling process can replace the ring forging process under the condition of the same wall thickness forging ratio to form cylindrical ports,and the cylindrical parts with uniform deformation can be obtained under the premise that the ring blanks are fully forged.