【摘要】：角接接頭旋轉(zhuǎn)電弧傳感器焊接是焊接行業(yè)新技術(shù),其焊接工件冷卻后,工件力學(xué)性能較好、焊道寬等優(yōu)點(diǎn),是國(guó)內(nèi)外焊接行業(yè)研究的熱點(diǎn)。又因隨著建筑、船舶等行業(yè)的發(fā)展,旋轉(zhuǎn)電弧焊接應(yīng)用越來越廣,普通焊接不能滿足工件質(zhì)量的要求,迫切需要對(duì)旋轉(zhuǎn)電弧角接接頭焊接特性進(jìn)行研究。旋轉(zhuǎn)電弧焊接過程中,由于角接接頭焊縫自身的特性,影響工件質(zhì)量的焊接工藝參數(shù)因子較多,各因子互相交叉影響,使焊縫成形、熔池形狀及焊后工件變形、焊縫缺陷的研究變得復(fù)雜,與非旋轉(zhuǎn)電弧焊接相比,焊絲端部具有旋轉(zhuǎn)運(yùn)動(dòng)作用,也導(dǎo)致其焊接熱源模型更加復(fù)雜。而不同焊接因子及焊接熱源,會(huì)導(dǎo)致焊接溫度場(chǎng)、應(yīng)力場(chǎng)及焊后工件變形的不同。為獲得較好焊接質(zhì)量與控制變形,有必要對(duì)其焊接工藝參數(shù)進(jìn)行優(yōu)化及焊接數(shù)值模擬進(jìn)行研究。本文根據(jù)文獻(xiàn)分析與前期研究,設(shè)旋轉(zhuǎn)電弧為順時(shí)針,旋轉(zhuǎn)半徑為3mm,焊炬夾角為45?,以5mm厚碳鋼為母材,采用MAG(Metal Active Gas Arc Welding)焊接。首先對(duì)焊接工藝參數(shù)進(jìn)行優(yōu)化研究,結(jié)合經(jīng)驗(yàn)法及參考文獻(xiàn),并考慮各個(gè)因子互相作用,在Minitab軟件中,設(shè)焊接電壓、焊接電流分別與焊接速度、旋轉(zhuǎn)頻率互相交叉作用,而旋轉(zhuǎn)頻率又與焊接速度、干伸長(zhǎng)相互交叉影響,采用焊接電壓、焊接電流、焊接速度、旋轉(zhuǎn)頻率、干伸長(zhǎng)及氣體流量,6因子3水平的方法,利用田口算法,建立正交模型。根據(jù)回歸分析法、方差法及平均值法進(jìn)行分析,得出不同因子之間的關(guān)系及好的焊接工藝參數(shù),結(jié)果表明,焊縫成形質(zhì)量分?jǐn)?shù)在11.8分,熔寬誤差在1.4附近,余高誤差0.31~0.34,會(huì)出現(xiàn)畸變現(xiàn)象。針對(duì)角接接頭旋轉(zhuǎn)電弧焊接熱源模型建立,考慮其焊縫特性并引入焊炬夾角,在雙橢球熱源基礎(chǔ)上對(duì)其熱源模型進(jìn)行改進(jìn),建立新的焊接熱源模型,使其能夠更加精確描述旋轉(zhuǎn)電弧焊縫形成過程。文中設(shè)焊炬夾角為45?,對(duì)角焊縫進(jìn)行分析,提出焊縫參數(shù)分布不對(duì)稱的特點(diǎn),并求出焊縫熱源參數(shù)之間的關(guān)系,得出寬度比例系數(shù)k=1.11,建立焊絲端部運(yùn)動(dòng)軌跡,并根據(jù)不同旋轉(zhuǎn)頻率分析焊絲端部軌跡運(yùn)動(dòng)情況。對(duì)于焊接工件,其熔池形態(tài)尺寸,焊縫成形特點(diǎn)、工件殘余應(yīng)力分布、裂紋大小分布及變形都與工件質(zhì)量密切相關(guān),為解決焊接中出現(xiàn)的問題,因此需要對(duì)旋轉(zhuǎn)電弧角接接頭焊接溫度場(chǎng)分布,應(yīng)力場(chǎng)分布進(jìn)行數(shù)值模擬。首先根據(jù)文獻(xiàn)得出不同溫度下的物理材料性能參數(shù)及熱焓值,其次在Ansys軟件中,選用SOLID70單元,進(jìn)行溫度場(chǎng)模擬分析,在應(yīng)力場(chǎng)數(shù)值模擬時(shí),選用SOLID5單元,采用直接耦合法模擬。在焊縫與熱影響區(qū)采用拖拉及掃略網(wǎng)格劃分,在其他地方采用映射網(wǎng)格,采用單元組件及節(jié)點(diǎn)組件進(jìn)行殺死或激活。根據(jù)實(shí)際焊接情況設(shè)置初始邊界條件,采用物理化學(xué)處理及反演算法,得出改進(jìn)型旋轉(zhuǎn)電弧雙橢質(zhì)量分?jǐn)?shù),并對(duì)其數(shù)值模擬。得出角接接頭旋轉(zhuǎn)電弧焊接熔池的形成過程;分析了不同時(shí)刻的熱循環(huán)曲線,動(dòng)態(tài)熱源溫度場(chǎng)變化,得出靠近上側(cè)板能量較高,易形成咬邊,靠近熱源中心前端的溫度要高于熱源中心處及后面部分,上側(cè)板散熱梯度要大于下側(cè)板;研究了動(dòng)態(tài)應(yīng)力場(chǎng)分布,冷卻后應(yīng)力分布,不同路徑應(yīng)力變化及工件變心等問題,得出初始焊接時(shí)上側(cè)板變形角度為°3 10′大于下側(cè)板變形的°2 30′;在焊接末端下側(cè)板變形角度為°3 20′,上側(cè)板變形角度為°2 28′比無旋轉(zhuǎn)時(shí)變形小;接近熱影響區(qū)內(nèi)1.31mm左右,拉應(yīng)力急劇增大應(yīng)力變量減小,增量斜率為負(fù);在冷卻后,上側(cè)板在X,Y,Z殘余應(yīng)力最大值及畸變程度要小于下側(cè)板,并且下側(cè)板變形更加不規(guī)則,出現(xiàn)危險(xiǎn)區(qū)域頻率更高。以上研究成果,可為角接接頭旋轉(zhuǎn)電弧焊接工藝參數(shù)選擇,結(jié)構(gòu)設(shè)計(jì)、焊接裝夾設(shè)計(jì)、防止工件變形及工程施工提供理論參考,促進(jìn)了旋轉(zhuǎn)電弧傳感器焊接的應(yīng)用及推廣。
[Abstract]:Rotating arc sensor with angular joint is a new technology in welding industry. After the welding workpiece is cooled, the mechanical properties of the workpiece are better, the welding path is wide and so on. It is a hot spot in the welding industry at home and abroad. And because of the development of the building, ship and other industries, the application of rotating arc welding is becoming more and more wide, and the ordinary welding can not meet the requirements of the quality of the workpiece. In the process of rotating arc welding, there are many factors affecting the quality of the workpiece in the process of rotating arc welding, and the factors affecting the quality of the workpiece are many. The factors of each factor cross influence each other, so that the weld formation, the shape of the weld pool and the deformation of the workpiece after welding are complicated, and the research of the weld defect is complicated. Compared with the non rotating arc welding, the end of the wire has a rotating motion, and the welding heat source model is more complex, and the different welding factors and welding heat sources will lead to the welding temperature field, the stress field and the deformation of the post weld workpiece. In this paper, according to the literature analysis and previous research, we set up the rotating arc as clockwise, the rotation radius 3mm, the torch angle of 45?, the 5mm thick carbon steel as the parent material and the MAG (Metal Active Gas Arc Welding) welding. First, the parameters of the welding process are optimized, combined with the experience method and the reference literature, and the examination is taken. Considering the interaction of each factor, in the Minitab software, the welding voltage is set up, the welding current is intersecting with the welding speed and the rotation frequency respectively, and the rotation frequency is intersecting with the welding speed and the dry elongation, and the welding voltage, welding current, welding speed, rotation frequency, dry elongation and gas flow, 6 factor and 3 level are used. The orthogonal model is established by Taguchi algorithm. According to the regression analysis, variance method and mean value method, the relationship between different factors and good welding parameters are obtained. The results show that the weld forming quality score is 11.8, the weld width error is around 1.4, the residual height error is 0.31~0.34, and the distortion will occur. The heat source model of arc welding is set up. Considering its weld characteristics and introducing the torch angle, the heat source model is improved on the base of double ellipsoid heat source, and a new welding heat source model is established to make it more accurate to describe the forming process of the welding seam. The angle of the torch is 45? The angle weld is analyzed and the weld parameters are divided. The relationship between the parameters of the heat source of the welding seam is found and the width ratio coefficient k=1.11 is obtained. The track of the end of the welding wire is established, and the track motion of the wire ends is analyzed according to the different rotation frequency. The shape and size of the weld pool, the shape of the weld, the distribution of the residual stress and the distribution of the crack size and the distribution of the crack size are used for the welding work. The deformation is closely related to the quality of the workpiece. In order to solve the problems in the welding, it is necessary to simulate the distribution of the temperature field and the distribution of the stress field of the rotating arc angle joint. First, the performance parameters and enthalpy values of physical materials at different temperatures are obtained according to the literature. Secondly, in the Ansys software, the SOLID70 unit is selected to carry out the temperature. In the numerical simulation of the stress field, the SOLID5 element is selected and the direct coupling method is used in the numerical simulation of the stress field. The mapped mesh is used in the weld and the heat affected zone, the mapping grid is used in other places, the unit components and the node components are used to kill or activate. The original boundary conditions are set up according to the actual welding condition and the object is used. In the process of chemical treatment and inversion, the mass fraction of the improved rotating arc double ellipsoid is obtained, and its numerical simulation is carried out. The forming process of the welding pool of the rotating arc welding of the angle joint is obtained. The thermal cycle curve and the change of the temperature field of the dynamic heat source are analyzed at different time. It is concluded that the energy of the plate near the upper side is high, and the edge is easily formed, close to the front end of the heat source center. The temperature of the upper side plate is higher than the center and the rear part of the heat source. The thermal gradient of the upper plate is greater than that of the lower side plate. The distribution of the dynamic stress field, the stress distribution after cooling, the change of the stress of the path and the change of the workpiece are studied. The deformation angle of the upper side plate is 310 'greater than that of the lower side plate deformation at the initial welding, and it is under the welding end. The deformation angle of the side plate is 320 ', and the deformation angle of the upper side is less than that of no rotation. Near the 1.31mm in the heat affected zone, the tensile stress increases sharply and the increment slope is negative. After cooling, the maximum and distortion of the upper side plate in X, Y, Z is less than that of the lower side plate, and the deformation of the lower side plate is less than that of the lower side. The above research results can provide theoretical reference for the selection of technological parameters, structure design, welding clamp design, prevention of workpiece deformation and engineering construction, and promote the application and popularization of the welding of rotating arc sensor.
【學(xué)位授予單位】：南昌大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TG457.11

【參考文獻(xiàn)】

相關(guān)期刊論文 前2條

1 張利國(guó);姬書得;方洪淵;劉雪松;;分段焊的焊接順序?qū)形接頭殘余應(yīng)力場(chǎng)的影響[J];焊接學(xué)報(bào);2006年12期

2 熊震宇;董潔;謝雨田;蔣海俠;;焊接過程的有限元模擬[J];南昌航空大學(xué)學(xué)報(bào)(自然科學(xué)版);2008年02期

相關(guān)碩士學(xué)位論文 前1條

1 劉翠霞;旋轉(zhuǎn)電弧自保護(hù)焊焊縫成形及自動(dòng)跟蹤的研究[D];華南理工大學(xué);2011年

，

本文編號(hào)：2162814