【摘要】：鈦的優(yōu)異性能給很多行業(yè)帶來了嶄新的發(fā)展前景,鈦材被大量運用在航天航空、國防工業(yè)等行業(yè)中。因此,國家正在重點發(fā)展鈦產(chǎn)業(yè),提升鈦材的生產(chǎn)能力和加工能力。利用電子束冷床熔煉爐生產(chǎn)大規(guī)格鈦扁錠是當今社會生產(chǎn)鈦材的主要生產(chǎn)方式。為了得到優(yōu)質(zhì)的大規(guī)格鈦扁錠,深入了解鈦扁錠凝固過程的規(guī)律十分重要。本文主要研究大規(guī)格鈦扁錠半連鑄凝固過程中,溫度場的分布以及溫度場和應(yīng)力場的耦合行為。大規(guī)格鈦扁錠的生產(chǎn)過程中,不同的工藝生產(chǎn)條件對其凝固過程的影響較為明顯,本文增加利用有限元軟件ProCAST對大規(guī)格鈦扁錠進行溫度場的穩(wěn)態(tài)數(shù)值模擬計算、溫度場非穩(wěn)態(tài)數(shù)值模擬計算以及應(yīng)力場的數(shù)值模擬計算,分析不同工藝生產(chǎn)條件下,溫度場和應(yīng)力場的變化規(guī)律。在半連鑄過程中,鈦扁錠的固液界面形貌對其組織的形成有著重要影響。本文首先采用穩(wěn)態(tài)數(shù)值模擬的方法,重點研究了澆注溫度和拉錠速度對鈦扁錠凝固過程的固液界面的影響規(guī)律。對鈦扁錠進行溫度場穩(wěn)態(tài)模擬計算后,獲得了澆注溫度和拉錠速度對鈦扁錠凝固達到穩(wěn)態(tài)時凝固界面形貌和固相分數(shù)的影響機制。大規(guī)格鈦扁錠的半連鑄過程中,熔池形貌和過渡區(qū)長度對鈦錠組織的形成有著重要的影響。本文采用非穩(wěn)態(tài)數(shù)值模擬的方法,重點研究澆注溫度和拉錠速度對大規(guī)格鈦扁錠熔池形貌和過渡區(qū)長度的影響規(guī)律。研究表明,隨著澆注溫度和拉錠速度的增加,過渡區(qū)長度呈線性增加,固相分數(shù)和熔池形貌變化區(qū)域的長度呈線性減小。鈦錠熔池深度和鈦錠1/4處熔池的深度呈線性增加。相對于澆注溫度,拉錠速度對非穩(wěn)態(tài)過渡區(qū)和固相分數(shù)的影響更為顯著。大規(guī)格鈦扁錠的半連鑄過程中,應(yīng)力場的分布規(guī)律對鈦錠質(zhì)量有著重要的影響。經(jīng)研究表明：鈦錠在冷卻凝固初期,表面應(yīng)力大,隨著冷卻凝固時間的增加,內(nèi)部的應(yīng)力明顯增加；鈦錠的兩側(cè)和錠頭部位應(yīng)力較大,隨著冷卻凝固時間的增加,鈦錠兩側(cè)的有效應(yīng)力逐漸增大,最后逐步趨于平緩。鈦錠兩側(cè)與錠頭發(fā)生了形變,并且鈦錠兩側(cè)形變明顯。
[Abstract]:The excellent performance of titanium has brought new development prospects for many industries. Titanium materials are widely used in aerospace, national defense industry and other industries. Therefore, the state is developing the titanium industry, improving the production capacity and processing capacity of titanium. The production of large titanium flat ingot by using electron beam cold bed smelting furnace is the main part of the production of titanium materials in the society. In order to obtain high quality and large scale titanium flat ingot, it is very important to understand the law of solidification process of titanium flat ingot. In this paper, the distribution of temperature field and coupling behavior of temperature field and stress field in the solidification process of large titanium flat ingot in half continuous casting are mainly studied. In the production process of large flat titanium ingot, different process conditions are made. The influence of the solidification process is more obvious. In this paper, the finite element software ProCAST is used to calculate the steady state numerical simulation of the temperature field of the large flat titanium ingot, the unsteady numerical simulation calculation of the temperature field and the numerical simulation of the stress field, and the variation of the temperature field and stress field under different production conditions. In the process of casting, the solid-liquid interface morphology of the flat titanium ingot has an important influence on the formation of its microstructure. Firstly, the influence of the pouring temperature and the ingot velocity on the solid liquid interface of the flat ingot in the titanium flat ingot is studied by the steady state numerical simulation. In the semi continuous casting process of large flat titanium ingot, the morphology of the molten pool and the length of the transition zone have an important influence on the formation of the titanium ingot. The study shows that the length of the transition zone increases linearly with the increase of pouring temperature and the speed of the ingot, and the length of the region of the change of the solid fraction and the morphology of the molten pool decreases linearly. The depth of the molten pool and the depth of the molten pool at the 1/4 ingot at the titanium ingot are linearly increased. In the semi continuous casting process of large scale titanium flat ingot, the distribution of stress field has an important influence on the quality of titanium ingot during the semi continuous casting process of large flat titanium ingot. The stress on both sides and ingot head parts of the titanium ingot is greater. With the increase of cooling and solidification time, the effective stress on both sides of the titanium ingot increases gradually, and finally tends to be gentle. The deformation of the two sides of the ingot and the head of the ingot has been deformed, and the deformation of the two sides of the titanium ingot is obvious.
【學位授予單位】：昆明理工大學
【學位級別】：碩士
【學位授予年份】：2016
【分類號】：TG292
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本文編號：2131060