本文選題：復合熱源　切入點：高熔點材料　出處：《南京理工大學》2017年碩士論文　論文類型：學位論文

【摘要】：隨著焊接技術的不斷發(fā)展,"綠色焊接"的理念被提出,如何減少焊接過程中的弧光、粉塵、噪音等有害物質(zhì),降低對操作人員身體的傷害,成為該理念重要研究內(nèi)容。攪拌摩擦焊(FSW)正是在這一時期從發(fā)明到廣泛應用迅速發(fā)展起來,攪拌摩擦焊接過程中沒有電弧、粉塵顆粒和有毒臭氧及氮化物等傳統(tǒng)熔化焊的缺點,且此焊接方法為固相連接,避免了金屬熔化再凝固帶來的硬質(zhì)相缺陷。目前FSW主要應用于鋁、鎂等低熔點合金,而在高熔點金屬材料方面的實際工程應用幾乎沒有。為拓展攪拌摩擦焊在高熔點材料方面的應用,本文針對高熔點材料Q235A鋼薄板復合熱源攪拌摩擦焊展開數(shù)值模擬計算的研究,具體內(nèi)容如下:(1)針對無針光軸肩攪拌頭的攪拌摩擦機理,提出中心到邊緣熱輸入非線性增大的反高斯攪拌摩擦焊熱源模型。利用有限元分析軟件ANSYS對TIG電弧+攪拌摩擦焊+底部預熱復合熱源高熔點材料鋼薄板對接焊先進行溫度場的熱分析計算,得出焊接中溫度全過程。利用自主設計的熱電偶測溫系統(tǒng)測量工件上特征點的熱循環(huán)曲線,并與模擬值曲線進行對比,擬合程度非常高,驗證了熱源模型與散熱條件處理的正確性。(2)利用順序(間接)耦合方法將熱分析結(jié)果通過載荷形式施加到結(jié)構(gòu)求解計算中,求解計算高熔點材料鋼薄板復合熱源焊接過程中的應力變化與殘余應力分布,得到焊接過程應力變化的規(guī)律。通過熱彈塑性法計算出薄板的焊后變形量,利用百分表測量出對接板的相對變形量,對比試驗變形測量值基本吻合,驗證了結(jié)構(gòu)計算方式與約束載荷的正確。(3)通過單因素變化試驗對比與正交模擬試驗的方法,分析了不同焊接工藝參數(shù)對高熔點材料鋼薄板復合熱源焊接過程中焊縫溫度變化影響規(guī)律和程度,研究表明:工藝參數(shù)的變化使得焊縫上峰值溫度出現(xiàn)整體上升或下降趨勢,且各因素對焊接溫度的影響程度大小排列為焊接速度TIG電弧焊電流攪拌頭轉(zhuǎn)速。
[Abstract]:With the continuous development of welding technology, the concept of "green welding" has been put forward, how to reduce the arc, dust, noise and other harmful substances in the welding process, and reduce the damage to the operator's body. It is in this period that FSW has developed rapidly from its invention to its wide application. In the process of FSW, there is no arc, dust particles, toxic ozone, nitride and other shortcomings of traditional fusion welding. This welding method is solid phase bonding, which avoids the hard phase defect caused by melting and solidification. At present, FSW is mainly used in low melting point alloys such as aluminum, magnesium, etc. In order to expand the application of friction stir welding in high melting point material, the numerical simulation of high melting point material Q235A steel sheet composite heat source friction stir welding is carried out in this paper. The specific contents are as follows: 1) the friction mechanism of the shoulder stir head without a needle, A heat source model of anti-#china_person0# friction stir welding with nonlinear heat input from center to edge is proposed. The heat source of high melting point steel sheet with preheated composite heat source at the bottom of TIG arc friction stir welding is first welded by finite element analysis software ANSYS. Thermal analysis and calculation of the temperature field, The whole process of welding temperature is obtained. The characteristic point thermal cycle curve of workpiece is measured by the self-designed thermocouple temperature measuring system, and compared with the simulated value curve, the fitting degree is very high. The correctness of heat source model and heat dissipation condition treatment is verified. The sequential (indirect) coupling method is used to apply the results of thermal analysis to the structural solution by means of load form. The stress variation and residual stress distribution in the welding process of high melting point steel sheet are calculated, and the variation of stress in welding process is obtained. The deformation of the plate after welding is calculated by thermoelastic-plastic method. The relative deformation of the butt plate is measured by using the percentile, and the measured value of the deformation in the contrast test is basically consistent, which verifies that the calculation method of the structure is correct and the constraint load is correct. The method of comparing the single factor variation test with the orthogonal simulation test is verified. The influence of different welding process parameters on weld temperature variation during welding of high melting point steel sheet with composite heat source is analyzed. The results show that the peak temperature of weld increases or decreases with the change of process parameters. The influence of various factors on welding temperature is arranged as welding speed, TIG arc welding current stirring head speed.
【學位授予單位】：南京理工大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TG453.9

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