本文關(guān)鍵詞： 大型餅類鍛件 預(yù)鐓粗 終鍛成形 數(shù)值模擬　出處：《東南大學(xué)》2016年碩士論文　論文類型：學(xué)位論文

【摘要】：管板、封頭和端蓋等核電用大型餅類鍛件是核反應(yīng)堆和蒸汽發(fā)生器的重要部件,工作環(huán)境惡劣,其鍛造質(zhì)量直接關(guān)系到核電站的運行安全。本文根據(jù)大型餅類鍛件的鍛造技術(shù)要點制定預(yù)鐓粗和終鍛成形的工藝方案,并基于DEFORM-3D仿真分析軟件建立有限元模型對其鍛造過程進(jìn)行數(shù)值模擬。分別從鍛件內(nèi)部應(yīng)力場、應(yīng)變場的分布和變化規(guī)律等方面研究了不同工藝參數(shù)下的寬平砧預(yù)鐓粗工藝、錐臺砧預(yù)鐓粗工藝和終鍛成形工藝對鍛件質(zhì)量的影響規(guī)律,以獲得合理的工藝方案和工藝參數(shù),指導(dǎo)實際鍛造過程。研究了寬平砧預(yù)鐓粗時,不同初始高徑比坯料的應(yīng)力場和應(yīng)變場的分布規(guī)律；結(jié)果表明,端面附近存在較大的難變形區(qū),且比例隨著壓下率線性增大；心部區(qū)域的應(yīng)變增大較快,導(dǎo)致心部在高度方向上應(yīng)變均勻性的急劇下降,從而產(chǎn)生層狀剪切裂紋；從坯料心部獲得三向壓應(yīng)力狀態(tài)、控制側(cè)表面的切向拉應(yīng)力和避免心部出現(xiàn)層狀裂紋的應(yīng)變條件出發(fā),不同初始高徑比坯料的壓下率應(yīng)嚴(yán)格控制在一定范圍內(nèi)。針對寬平砧鐓粗時應(yīng)變不均的問題,將預(yù)鐓粗工序分為錐臺砧鐓粗和平砧端面整平兩個階段,分別研究了錐臺砧錐角和壓下率對鐓粗過程的影響,平砧旋轉(zhuǎn)鍛造方式和下砧砧形對端面整平過程的影響；結(jié)果表明,錐臺砧能夠有效促使端面難變形區(qū)變形,并增大心部大變形區(qū)范圍,提高鍛件的應(yīng)變均勻程度,同時降低側(cè)表面的切向拉應(yīng)力和鍛造設(shè)備載荷;綜合分析應(yīng)變均勻程度、剪切裂紋的產(chǎn)生、坯料表面的切向拉應(yīng)力以及心部的應(yīng)力狀態(tài),對于初始高徑比為2.0的坯料,最大壓下率取60%,錐臺砧錐角取14°～15°較為有利；在端面整平過程中,采用外緣旋轉(zhuǎn)鍛造法,鍛打上端面時上砧使用窄平砧,下砧使用錐臺砧,可使心部獲得較好的三向壓應(yīng)力狀態(tài),且應(yīng)變較為均勻。對終鍛成形工序進(jìn)行了模擬分析,分別研究了4種排砧工藝方案和2種旋轉(zhuǎn)鍛造工藝方案對鍛件內(nèi)部應(yīng)力應(yīng)變狀態(tài)的影響：結(jié)果表明,對稱排砧工藝能夠在壓中部區(qū)域時獲得相對較大的靜水壓應(yīng)力,有利于鍛合心部缺陷,同時相鄰道次錯砧能夠消除內(nèi)部應(yīng)變的不均勻性,較大提高鍛件的變形均勻程度,有效降低產(chǎn)生剪切裂紋的可能性：對相鄰道次錯砧的排砧工藝的工藝參數(shù)進(jìn)行了研究,當(dāng)壓下率取15%并保證進(jìn)砧量大于臨界進(jìn)砧量可使鍛件獲得良好的應(yīng)力應(yīng)變狀態(tài)。
[Abstract]:Large cake forgings for nuclear power, such as tube plates, seals and end caps, are important components of nuclear reactors and steam generators, and work in harsh conditions. The forging quality is directly related to the operation safety of the nuclear power station. According to the main points of forging technology of the large cake forgings, the technological scheme of preheading and final forging is established in this paper. The forging process was simulated by finite element model based on DEFORM-3D software. The pre-upsetting process of wide flat anvil under different technological parameters was studied from the aspects of stress field and strain field distribution and variation law of forgings. The influence of preheading and final forging on the quality of forgings is studied in order to obtain reasonable technological scheme and parameters and guide the actual forging process. The distribution law of stress field and strain field of billet with different initial aspect ratio shows that there is a large area of difficult deformation near the end face, and the proportion increases linearly with the reduction rate, and the strain increases rapidly in the center region. As a result, the strain uniformity of the center decreases sharply in the height direction, thus the layered shear crack is produced, and the triaxial compressive stress state is obtained from the center of the blank, which controls the tangential tensile stress on the side surface and avoids the strain condition of the layered crack in the center. The reduction rate of blanks with different initial aspect ratios should be strictly controlled within a certain range. Aiming at the problem of uneven strain during upsetting of wide flat anvil, the preheading process is divided into two stages: conical anvil upsetting and anvil face leveling. The effects of cone angle and reduction rate on upsetting process, rotation forging mode of flat anvil and the influence of lower anvil shape on the end face leveling process are studied respectively, the results show that the cone anvil can effectively promote the deformation of the hard deformation zone of the end face. At the same time, the tangential tensile stress on the side surface and the load of forging equipment are reduced, and the strain uniformity degree is analyzed synthetically, and the shear crack is produced, and the strain uniformity is increased, the strain uniformity of the forging is increased, and the tangential tensile stress and the forging equipment load are reduced. The tangential tensile stress on the surface of the blank and the stress state of the center are more favorable for the blank with the initial ratio of height to diameter 2.0, the maximum reduction rate is 60 and the cone angle of the cone anvil is 14 擄/ 15 擄. In the process of face leveling, the external edge rotating forging method is used. When the upper end face is forged, the upper anvil uses the narrow flat anvil and the lower anvil uses the cone bench anvil, which can make the center obtain a better triaxial compressive stress state, and the strain is more uniform. The final forging process is simulated and analyzed. The effects of four kinds of anvil arrangement and two rotating forging schemes on the stress and strain state of forgings are studied. The results show that the symmetrical anvil arrangement process can obtain relatively large hydrostatic stress in the middle part of the forging. At the same time, the adjacent secondary anvil can eliminate the inhomogeneity of internal strain and improve the deformation uniformity of forgings. The possibility of producing shear crack is effectively reduced: the technological parameters of the anvil discharging process of adjacent secondary anvil are studied. When the reduction rate is 15% and the quantity of anvil feed is larger than the critical anvil quantity, the forgings can obtain a good stress-strain state.
【學(xué)位授予單位】：東南大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：TM623;TG316

【相似文獻(xiàn)】

相關(guān)期刊論文 前10條

1 涂強;提高自由鍛件精度、節(jié)約原材料的途徑和措施[J];熱加工工藝;1984年04期

2 董洪業(yè);;船用透平鍛件及其檢驗[J];大型鑄鍛件;1985年01期

3 申秉琳,龔敬文,鄧徐幀,梁繼愚;20MnMoD低溫鍛件試驗研究[J];壓力容器;1990年02期

4 寧愛林,申奇志;環(huán)形鍛件各向性能的控制[J];邵陽高等專科學(xué)校學(xué)報;2000年03期

5 王曉慧;鍛件尺寸的設(shè)計[J];鍛壓技術(shù);2002年03期

6 王富軍;鍛件精度問題的分析[J];煤礦機械;2005年09期

7 李志廣;張健;趙麗華;翟海;;鍛件尺寸標(biāo)注原則的研究[J];金屬加工(熱加工);2008年23期

8 徐要剛;趙現(xiàn)朝;田志松;;激光測距法測量大鍛件尺寸[J];機械設(shè)計與研究;2008年06期

9 常懷德;王建新;楊慶光;;大鍛件在線測量新技術(shù)初探[J];一重技術(shù);2008年02期

10 李秀清;高乃杰;;軸承鍛件整徑工藝[J];金屬加工(熱加工);2008年17期

相關(guān)會議論文 前10條

1 李貴全;陳陽;;精密鍛件重量(體積)的精確計算方法[A];第十五屆中國科協(xié)年會第13分會場：航空發(fā)動機設(shè)計、制造與應(yīng)用技術(shù)研討會論文集[C];2013年

2 張龍;謝偉明;何顯中;吳運剛;岳茂雄;;大鍛件尺寸測量與控制系統(tǒng)的研制[A];中國自動化學(xué)會、中國儀器儀表學(xué)會2004年西南三省一市自動化與儀器儀表學(xué)術(shù)年會論文集[C];2004年

3 郭會光;陳慧琴;劉建生;何文武;;我國大型鍛造發(fā)展的研究[A];第六屆華北（擴大）塑性加工學(xué)術(shù)年會文集[C];2009年

4 賈振平;;帶殼體從動錐齒輪鍛件的工藝分析及探討[A];2010重慶汽車工程學(xué)會年會論文專輯[C];2010年

5 蔣理興;S∮窶，

本文編號：1542380