不同成形工艺对金属密封件坐封效果的影响

Influences of Different Forming Processes on Setting Performances of Metal Seal

针对整体机械加工成形的新型桥塞金属密封件在坐封后密封面出现裂纹缺陷的现象展开了研究。通过坐封过程力学分析和不同状态下组织形貌观察,得出产生裂纹的原因。在此基础上,提出金属密封件的液压成形工艺。采用数值模拟完成液压成形模具和工艺参数的优化设计,并进行密封件的液压成形试验和坐封试验。试验结果表明,液压成形工艺设置成形压力为180MPa、保压时间为5s时,所得金属密封件表面质量较好,坐封后不产生裂纹。液压成形金属密封件密封面不同状态下的组织形貌观测和液压成形过程中的受力分析进一步表明,液压成形过程中的径向压应力能够改善晶界开裂等现象,因此与整体机械加工成形的密封件相比,液压成形工艺可以明显改善坐封效果。

The cracks on the sealing surface of a new kind of metal seal in bridge plug formed by machining were studied,and the reasons were obtained by mechanics analysis and microstructure observation under different conditions.The hydraulic forming process for metal seals was proposed.The numerical simulation was employed to optimize the mold and process parameters of hydraulic forming,and hydraulic forming tests and metal seal tests were carried out according to the previous simulation results.The test results show that the quality of sealing surface is optimal when the pressure is as 180 MPa and the holding time is as 5 s,and there are no cracks on the surfaces after setting.The results of microstructure observation under different sealing surface conditions and mechanics analysis during hydraulic forming processes shows that the cracks may be eliminated by radial compressive stress of hydraulic forming.Therefore,the setting performances of metal seal may be greatly improved by hydraulic forming process comparing with original machining methods.