本文選題：雙絲GMAW焊接 + 電弧干擾　； 參考：《上海交通大學》2015年碩士論文

【摘要】：隨著船舶、汽車、航空航天等現(xiàn)代制造業(yè)的飛速發(fā)展,對于高效焊接技術(shù)的需求迫在眉睫。為了提高焊接效率,可以采用雙絲或多絲GMAW的方法。在雙絲GMAW焊接中的一個突出問題是由電磁力而產(chǎn)生的電弧干擾。因此,如何有效抑制或克服電弧干擾,成為焊接工作者一個重要的研究課題,另外,雙絲焊的焊接工藝參數(shù)匹配對焊縫成形、熔滴過渡的穩(wěn)定性也存在很大的影響。本文構(gòu)建了一套雙絲GMAW焊接平臺,包括自動焊接系統(tǒng)、電信號采集系統(tǒng)以及高速攝影系統(tǒng);針對焊接過程中的電弧形態(tài)、熔滴過渡模式、電流電壓波形進行系統(tǒng)的研究和分析,對電弧干擾的成因給出了解釋和抑制方法;分析了在雙絲GMAW焊接過程中弧長變化引起的穩(wěn)定焊接工作點的遷移;分析了工藝參數(shù)匹配對焊縫成形的影響規(guī)律,最后,采用雙絲GMAW對焊和jk焊E36鋼,對比分析了單絲和雙絲的焊接頭顯微組織、力學性能、焊接效率和極限速度。結(jié)果表明,單絲GMAW焊接電弧呈鐘罩型,焊接過程穩(wěn)定;雙絲GMAW焊接電弧會產(chǎn)生一定偏移,增大引導弧(前弧)電流使之大于跟隨弧(后弧),增大雙絲間距,采用混合保護氣替代純氬保護氣體都可以有效緩解電弧干擾現(xiàn)象,使焊接過程趨于穩(wěn)定。單絲GMAW焊接熔滴過渡模式為射滴+射流過渡,熔滴過渡穩(wěn)定。雙絲GMAW焊接熔滴過渡躁動性增強,過渡路徑向兩弧中心偏離,增大引導弧(前弧)電流使之大于跟隨弧(后弧),熔滴過渡過程會趨于穩(wěn)定。采用FLOW-3D模擬與實驗結(jié)合研究雙絲焊工藝參數(shù)對焊縫成形的影響,得到引導弧電流大于跟隨弧電流的這種電流配比下,熔池內(nèi)部同時存在“推-拉”流動方式和向外流動方式,焊縫成形更優(yōu)良,引導絲電流減小,不存在明顯的“推-拉”方式,只存在向外流動方式,出現(xiàn)液態(tài)金屬收縮和提前凝固現(xiàn)象,焊縫成型差。在雙絲焊應用方面,對比單絲GMAW與雙絲GMAW對接焊E36鋼,發(fā)現(xiàn)單絲與雙絲對接焊焊接接頭金相組織、力學性能相近。在相同速度下,雙絲焊接的效率要比單絲焊接高出37.5%;在相同電流電壓參數(shù)下,雙絲GMAW可以達到的無駝峰缺陷的極限焊接速度更高。將雙絲GMAW應用于60mm深度坡口大厚板的橫焊,采用最佳焊接規(guī)范參數(shù)可取得高效高質(zhì)量的焊縫成形。
[Abstract]:With the rapid development of modern manufacturing industry, such as ship, automobile, aerospace and so on, the demand of high efficiency welding technology is urgent. In order to improve welding efficiency, double wire or multi-wire GMAW can be used. A prominent problem in double wire GMAW welding is the arc interference caused by electromagnetic force. Therefore, how to effectively suppress or overcome the arc interference has become an important research topic for welding workers. In addition, the matching of welding parameters of double-wire welding also has a great impact on the stability of weld formation and droplet transfer. In this paper, a two-wire GMAW welding platform is constructed, including automatic welding system, electrical signal acquisition system and high-speed photography system, and the research and analysis of arc shape, droplet transfer mode, current and voltage waveform in welding process are carried out systematically. The cause of arc interference is explained and the method of restraining arc interference is given. The migration of stable welding point caused by arc length variation during double wire GMAW welding is analyzed. The influence of process parameter matching on weld forming is analyzed. The microstructure, mechanical properties, welding efficiency and limit speed of single wire and double wire welding joint were compared and analyzed by using double wire GMAW butt welding and JK welding E36 steel. The results show that the arc of single-wire GMAW welding is bell-shaped, and the welding process is stable, and the arc of double-wire GMAW welding will have a certain deviation, which will increase the current of guide arc (front arc) so as to be larger than that of the following arc (back arc), and increase the distance between two wires. The arc interference can be effectively alleviated by using mixed protective gas instead of pure argon protection gas, and the welding process tends to be stable. Single wire GMAW welding droplet transfer mode is jet transfer, droplet transfer stability. The mania of droplet transfer in two-wire GMAW welding is enhanced, the transition path deviates to the center of the two arcs, and the current of the guide arc (front arc) is larger than that of the following arc (rear arc), and the droplet transfer process tends to be stable. FLOW-3D simulation and experiment were used to study the influence of welding process parameters on weld formation. The results show that there are "push-pull" flow modes and outward flow modes in the molten pool when the guiding arc current is larger than the following arc current. The weld is better in forming, the guiding wire current is reduced, there is no obvious "push-pull" mode, there is only outward flow mode, liquid metal shrinkage and early solidification appear, and the weld formation is poor. In the application of double wire welding, compared with single wire GMAW and double wire GMAW butt welding E36 steel, it is found that the microstructure of single wire and double wire butt welding joint is similar and the mechanical properties are similar. At the same speed, the efficiency of double wire welding is 37. 5% higher than that of single wire welding, and under the same current and voltage parameters, the limit welding speed of double wire GMAW without hump defect is higher than that of single wire welding. The double wire GMAW is applied to the transverse welding of 60mm deep groove thick plate. The high efficiency and high quality weld forming can be obtained by adopting the best welding specification parameters.
【學位授予單位】：上海交通大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TG444

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相關(guān)期刊論文 前1條

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本文編號：1912842