本文選題：AZ31B鎂合金　切入點：DE-GMAW焊接　出處：《南昌大學(xué)》2015年碩士論文

【摘要】：焊接作為一種可靠的材料連接技術(shù),廣泛應(yīng)用于眾多工業(yè)領(lǐng)域,在社會經(jīng)濟持續(xù)發(fā)展中發(fā)揮著重要作用。近年來,隨著制造業(yè)的不斷發(fā)展,傳統(tǒng)的焊接方法越來越難以滿足高質(zhì)高效的生產(chǎn)要求,許多高效焊接方法陸續(xù)被提出來,雙電極氣體保護焊接方法就是其中之一,簡稱為DE-GMAW(Double-electrode gas metal arc welding)。本文中采用焊接溫度場以及應(yīng)力場的有限元分析理論,以AZ31B鎂合金作為實驗材料,在此基礎(chǔ)上對這種新型的焊接工藝進行數(shù)值模擬,研究DE-GMAW焊接旁路電弧的熱效率、焊件溫度場以及應(yīng)力場的分布規(guī)律,有助于優(yōu)化DE-GMAW焊接工藝參數(shù)。首先,本文中采用熔池圖像采集系統(tǒng)獲取AZ31B鎂合金DE-GMAW焊接熔池圖像,經(jīng)過VC++軟件對圖像處理后得到熔池尺寸。其次,采用ANSYS軟件建立適用于AZ31B鎂合金DE-GMAW焊接的復(fù)合熱源模型以及有限元模型,對其溫度場進行數(shù)值模擬,根據(jù)熔池尺寸的實驗值和模擬值確定旁路電弧熱效率的取值范圍。討論DE-GMAW焊接旁路電流對熔池尺寸以及母材熱輸入的影響,模擬結(jié)果與實驗基本一致,驗證了所建立模型以及熱源作用模式的正確性。最后,使用間接耦合法,利用ANSYS軟件計算AZ31B鎂合金DE-GMAW焊接應(yīng)力場,研究焊件動態(tài)應(yīng)力發(fā)展與殘余應(yīng)力分布,模擬結(jié)果與焊接理論符合;探討DE-GMAW焊接速度和電流影響焊件殘余應(yīng)力的規(guī)律;探索AZ31B薄板DE-GMAW焊中,不同焊件初始溫度對殘余應(yīng)力的影響,得到焊件初始溫度在50-100℃范圍內(nèi)可以有效地降低其殘余應(yīng)力。
[Abstract]:As a reliable material connection technology, welding is widely used in many industrial fields and plays an important role in the sustainable development of social economy.In recent years, with the continuous development of manufacturing industry, traditional welding methods are more and more difficult to meet the requirements of high quality and high efficiency production. Many efficient welding methods have been put forward one after another, one of which is two-electrode gas shielded welding method.Referred to as DE-GMAW(Double-electrode gas metal arc welding.In this paper, the finite element analysis theory of welding temperature field and stress field is adopted, and AZ31B magnesium alloy is used as experimental material. On this basis, the numerical simulation of this new welding process is carried out, and the thermal efficiency of bypass arc in DE-GMAW welding is studied.The distribution of temperature field and stress field is helpful to optimize DE-GMAW welding process parameters.Firstly, the weld pool image of AZ31B magnesium alloy DE-GMAW welding was obtained by using the weld pool image acquisition system, and the weld pool size was obtained after processing the image by VC software.Secondly, the composite heat source model and finite element model for DE-GMAW welding of AZ31B magnesium alloy are established by ANSYS software. The temperature field is numerically simulated, and the range of thermal efficiency of by-pass arc is determined according to the experimental value and simulation value of weld pool size.The influence of DE-GMAW welding bypass current on the size of molten pool and the heat input of base metal is discussed. The simulation results are in good agreement with the experimental results, and the correctness of the established model and the heat source action mode are verified.Finally, the indirect coupling method is used to calculate the stress field of DE-GMAW welding of AZ31B magnesium alloy by ANSYS software. The dynamic stress development and residual stress distribution of the welded parts are studied. The simulation results are in agreement with the welding theory.The influence of DE-GMAW welding speed and current on residual stress of welding piece is discussed, and the influence of different initial temperature on residual stress in DE-GMAW welding of AZ31B sheet is explored. It is concluded that the initial temperature of welding piece can effectively reduce the residual stress in the range of 50-100 鈩，

本文編號：1712244