本文關(guān)鍵詞： 橋塞 金屬密封 液壓成形 楔橫軋成形 坐封試驗(yàn)　出處：《沈陽航空航天大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：本文以一種自主開發(fā)的新型橋塞金屬密封件為研究對象,通過力學(xué)分析、數(shù)值模擬、組織觀察和試驗(yàn)研究等方式,進(jìn)行金屬密封件的結(jié)構(gòu)優(yōu)化設(shè)計(jì)、預(yù)機(jī)加成形和液壓成形組合加工工藝的研究,并探討了高效楔橫軋代替機(jī)加制坯的可行性。主要內(nèi)容如下:通過坐封試驗(yàn)和模擬分析,闡明了金屬密封件在坐封后翻轉(zhuǎn)直角槽和密封面拱形薄壁圓弧內(nèi)緣根部產(chǎn)生裂紋的原因。以翻轉(zhuǎn)直角槽和密封面薄壁圓弧內(nèi)緣根部過度圓角的大小為設(shè)計(jì)變量構(gòu)建數(shù)學(xué)優(yōu)化模型,優(yōu)化結(jié)果表明:翻轉(zhuǎn)直角槽過度圓角取1.5 mm、薄壁圓弧內(nèi)緣根部過度圓角取3.0mm時(shí),坐封后金屬密封件沒有出現(xiàn)裂紋缺陷。通過坐封過程力學(xué)分析和不同狀態(tài)下組織形貌觀察,得出整體機(jī)加成形的金屬密封件在坐封后密封面產(chǎn)生裂紋的原因;在此基礎(chǔ)上,提出了金屬密封件的液壓成形工藝。結(jié)果表明,液壓成形工藝成形壓力設(shè)置為180MPa、保壓時(shí)間為5s時(shí),所得金屬密封件密封面拱形薄壁圓弧成形性、表面質(zhì)量較好,坐封后不產(chǎn)生裂紋。液壓成形金屬密封件密封面不同狀態(tài)下的組織形貌觀測和液壓成形過程中的受力分析,進(jìn)一步表明液壓成形過程中的徑向壓應(yīng)力能夠改善機(jī)加導(dǎo)致的表層組織流線破壞和晶界開裂等現(xiàn)象,因此與整體機(jī)加成形的密封件相比可大大提高最終的坐封效果。針對金屬密封件采用機(jī)加成形存在裝夾困難、材料利用率和生產(chǎn)效率低下等問題,提出金屬密封件外輪廓的楔橫軋成形工藝,采用DEFORM-3D完成楔橫軋成形模具和工藝參數(shù)的優(yōu)化設(shè)計(jì)。結(jié)果表明,金屬密封件楔橫軋工藝成形角α取30°、展寬角β取8°、軋制速度V設(shè)定408mm/s、軋制溫度T設(shè)定950℃時(shí),所得金屬密封件尺寸誤差不超過4%,滿足設(shè)計(jì)規(guī)格要求,最大軋制力約為120.0KN,從理論上初步驗(yàn)證了金屬密封件楔橫軋高效精確預(yù)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 偽 is 30 擄, the broadening angle 尾 is 8 擄, the rolling speed V is 408mm / s, and the rolling temperature T is 950 鈩，

本文編號：1465085