复杂异形截面薄壁环形件动模液压成形研究

 液压成形技术是成形薄壁零件的一种有效的解决方法。针对具有异形截面结构的某型发动机高温合金薄壁环形件,提出了液压成形结合动模轴向加载的复合成形方法,依据塑性力学方法和增量理论对成形过程进行了应力应变特征分析,并建立了有限元模型。基于有限元模拟和工艺试验,研究了筒坯成形区高度和型腔液压加载路径等关键工艺参数对零件成形结果的影响,探讨了成形过程中壁厚过度减薄、材料堆积"折叠"、形状不对称等失效形式,提出了优化的工艺参数。结果表明,提出的工艺方法可实现复杂异形截面薄壁环形件的整体精确成形,采用优化的筒坯成形区高度和液压加载路径可获得壁厚分布均匀、成形质量较好的零件。

Hydroforming of Complicated Thin-walled Circular Parts with Irregular Section by Using Moving Dies

Hydroforming is an effective method for manufacturing thin-walled parts.In order to develop a forming process of complicated thin-walled circular superalloy parts with irregular section,a technology scheme is proposed consisting of hydroforming with axial feeding by using moving dies.Meanwhile,an analysis is made of stress characteristic and strain state based on plasticity method and incremental theory,and its finite element models are built.The effect of the key process parameters,including the height of forming area for cylinder blank and loading paths of cavity pressure on the quality of the parts,is explored with the assistance of numerical simulations and verification experiments.Furthermore,the failure modes during the forming process,including excessive wall thinning,accumulation folding and configurational asymmetry are discussed,and the technological parameters are optimized.The results indicate that the proposed technological method is feasible for the accurate integral forming of complicated thin-walled circular parts with irregular section;moreover,the parts with uniform thickness distribution and high quality can be successfully formed by using optimal height of forming area and loading path of cavity pressure.