阀盖模锻成形模拟分析与试验验证

目的 某型号不锈钢阀盖是一种典型的长肋条内空型零件,在模锻制造过程中,阀盖锻件容易出现不同程度的折叠和裂纹缺陷,亟需改进成形工艺以提升合格率.方法 采用有限元方法分析坯料在制坯/预锻/终锻全流程的金属流动规律和终锻件成形质量,得到最佳成形工艺方案.结果 方坯在后续成形时易产生横向流动,且局部充型不饱满;六边型坯在预成形和终成形时流动均匀、横向流动小,且有效抑制了充型不饱满缺陷;预制坯在过渡区长度过短,产生了折叠缺陷;采用六边形坯料和增加过渡区长度可以获得无缺陷阀体锻件.结论 采用新工艺制备的阀盖锻件合格率达到了100％,通过全流程工艺分析,能够得到金属流线规律,进而优化模锻成形方案,改善成形质量.

Simulation Analysis and Test Verification of Valve Cover Forming

A certain type of stainless steel valve cover is a typical hollow part with long ribs. In the process of die forging, the valve cover forgings are prone to fold and crack defects in different degrees, so it is urgent to improve the forming process to increase the qualified rate. The metal flow law and the forming quality of the final forging were analyzed by finite element method in the whole process of billet/pre-forging/final forging, and the best forming process scheme was obtained. The square billet was easy to produce transverse flow and the local filling was not full in subsequent forming, while the hexagonal billet flowed evenly in pre-forming and final forming and the transverse flow was small and the filling defects could be effectively suppressed. In the meantime, it was found that both billets had folding defects in the short transition zone. The defect-free valve forgings could be obtained by the use of hexagonal billet and increase of transition length. The qualified rate of the valve cover forgings prepared by new process is 100%. Through the analysis on whole process, the metal flow law is obtained to optimize the die forging scheme and effectively improve the forming quality.