上机匣成形中的质量缺陷及对策

上机匣是直升机的关键零件，几何形状复杂，锻件足寸大，性能指标要求高，成形中容易产生粗晶、折叠、流线不顺等质量缺陷。本文采用纯铅为模拟材料，对上机匣成形方案进行了试验研究；利用等温精锻工艺，镶块式模具结构等，成功地锻制了上机匣锻件。其力学性能，显微组织和足寸精度均符合要求。

LIMITATIONS AND COUNTERMEASURES OF HELICOPTER UPPER HOUSING FORMING PROCESSES

Upper housing, a key part of helicopter, is difficult to be formed owing to its big size, complex geometry and high demands in requirements as to its characteristics and properties. In order to design the forming process properly, the forming process of the upper housing was investigated with the aid of physical modeling using pure lead. Isothermal forging technology and combined die structure were adopted. The upper housing was forged successfully with the above isothermal precision forging technique. The mechanical properties, micro and macro structure as well as the accuracy of the component satisfied the user's requirements.