深井专用金属密封件成形工艺数值模拟与试验研究

发布时间：2018-01-26 07:44

  本文关键词： 桥塞 金属密封 液压成形 楔横轧成形 坐封试验　出处：《沈阳航空航天大学》2017年硕士论文　论文类型：学位论文

【摘要】：本文以一种自主开发的新型桥塞金属密封件为研究对象,通过力学分析、数值模拟、组织观察和试验研究等方式,进行金属密封件的结构优化设计、预机加成形和液压成形组合加工工艺的研究,并探讨了高效楔横轧代替机加制坯的可行性。主要内容如下:通过坐封试验和模拟分析,阐明了金属密封件在坐封后翻转直角槽和密封面拱形薄壁圆弧内缘根部产生裂纹的原因。以翻转直角槽和密封面薄壁圆弧内缘根部过度圆角的大小为设计变量构建数学优化模型,优化结果表明:翻转直角槽过度圆角取1.5 mm、薄壁圆弧内缘根部过度圆角取3.0mm时,坐封后金属密封件没有出现裂纹缺陷。通过坐封过程力学分析和不同状态下组织形貌观察,得出整体机加成形的金属密封件在坐封后密封面产生裂纹的原因;在此基础上,提出了金属密封件的液压成形工艺。结果表明,液压成形工艺成形压力设置为180MPa、保压时间为5s时,所得金属密封件密封面拱形薄壁圆弧成形性、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机加导致的表层组织流线破坏和晶界开裂等现象,因此与整体机加成形的密封件相比可大大提高最终的坐封效果。针对金属密封件采用机加成形存在装夹困难、材料利用率和生产效率低下等问题,提出金属密封件外轮廓的楔横轧成形工艺,采用DEFORM-3D完成楔横轧成形模具和工艺参数的优化设计。结果表明,金属密封件楔横轧工艺成形角α取30°、展宽角β取8°、轧制速度V设定408mm/s、轧制温度T设定950℃时,所得金属密封件尺寸误差不超过4%,满足设计规格要求,最大轧制力约为120.0KN,从理论上初步验证了金属密封件楔横轧高效精确预成形制坯的可行性。
[Abstract]:In this paper, a new self-developed bridge plug metal seal as the research object, through mechanical analysis, numerical simulation, organization observation and experimental study, the structure optimization design of the metal seal is carried out. The research of preforming and hydroforming combined processing technology and the feasibility of high efficiency cross wedge rolling instead of adding billet are discussed. The main contents are as follows: through setting test and simulation analysis. The causes of cracks in the inner edge of the arched thin-walled arc of the seal surface and the overturning corner of the inner edge of the inner edge of the thin-walled arc of the seal surface are explained. The design variable is the size of the excessive fillet of the inner edge of the inner edge of the reverse right-angle groove and the inner edge of the sealing surface. Build mathematical optimization model. The optimization results show that when the excessive fillet of the right groove is 1.5 mm and the inner edge of the thin-walled arc is 3.0 mm, the angle of the inner edge of the thin wall arc is 3.0 mm. Through mechanical analysis of seal process and observation of microstructure in different states, the reason of crack on seal surface of metal seal added by integral machine was obtained. On this basis, the hydroforming process of metal seal is proposed. The results show that the forming pressure is set to 180MPa and the holding time is 5s. The metal seal surface has good surface quality because of its arched thin-wall arc formability. The microstructure and morphology of the sealing surface of the metal seal in hydroforming process were observed and the mechanical analysis during the process of hydroforming was carried out. It is further shown that the radial compressive stress in hydroforming process can improve the failure of streamline and grain boundary cracking of the surface structure caused by mechanical loading. Therefore, compared with the integral sealing parts, the final sealing effect can be greatly improved. For metal seals, there are some problems such as difficult clamping, low material utilization rate and low production efficiency. The process of cross wedge rolling forming of metal seal is put forward. The optimization design of forming die and process parameters of cross wedge rolling is completed by DEFORM-3D. When the forming angle 伪 is 30 掳, the broadening angle 尾 is 8 掳, the rolling speed V is 408mm / s, and the rolling temperature T is 950 鈩，

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