本文選題：窄間隙焊 + 擺動(dòng)電弧　； 參考：《哈爾濱工業(yè)大學(xué)》2014年碩士論文

【摘要】：近幾年，隨著壓力容器、核電、海洋工程及油氣管道行業(yè)裝備的日趨大型化重型化，厚板厚管焊接結(jié)構(gòu)的應(yīng)用越來(lái)越廣泛，窄間隙全位置焊接的需求大幅增加。而立焊作為全位置焊接的重要組成部分，受重力的影響，如果工藝參數(shù)選擇不當(dāng)，容易出現(xiàn)熔池下淌，焊縫成形不良的問(wèn)題，焊接難度較大。 為了解決窄間隙焊接時(shí)的側(cè)壁熔合問(wèn)題，保證立焊接頭的焊接質(zhì)量與生產(chǎn)效率，設(shè)計(jì)了一個(gè)小型的擺動(dòng)電弧窄間隙焊炬，探索了窄間隙立焊時(shí)工藝參數(shù)對(duì)焊接穩(wěn)定性及焊縫成形的影響規(guī)律，確定了立向上焊和立向下焊的最佳工藝參數(shù)范圍，并在此基礎(chǔ)上完成了厚板單道多層焊試驗(yàn)，得到了無(wú)宏觀缺陷的立焊接頭，利用高速攝像技術(shù)對(duì)比分析了擺動(dòng)電弧立向上焊和立向下焊的熔滴過(guò)渡形式及電弧、熔池行為，為以后實(shí)現(xiàn)厚壁管道的擺動(dòng)電弧窄間隙全位置焊接做好準(zhǔn)備。 （1）首先設(shè)計(jì)并優(yōu)化了焊炬的電路系統(tǒng)、水冷系統(tǒng)和氣保護(hù)系統(tǒng)，經(jīng)實(shí)驗(yàn)驗(yàn)證，焊炬性能穩(wěn)定，能夠適應(yīng)長(zhǎng)時(shí)間焊接工作。 （2）研究了擺動(dòng)電弧窄間隙立向上焊和立向下焊時(shí)保護(hù)氣流量、焊接電流、焊接速度、擺動(dòng)角度、擺動(dòng)頻率及側(cè)壁停留時(shí)間對(duì)焊縫成形的影響，初步分析了不同工藝參數(shù)下的立向上和立向下焊焊縫成形特點(diǎn)及產(chǎn)生原因，進(jìn)行了25mm厚Q235鋼的立向上及立向下單道多層焊試驗(yàn)，得到了無(wú)宏觀缺陷的立焊焊接接頭。 （3）利用高速攝像技術(shù)觀察了擺動(dòng)電弧窄間隙GMAW的電弧行為及熔滴過(guò)渡，研究了窄間隙平焊時(shí)擺動(dòng)對(duì)電弧形態(tài)及熔滴過(guò)渡的影響，發(fā)現(xiàn)擺動(dòng)時(shí)由于受到離心力的作用，電弧和熔滴都偏離焊絲軸線，且熔滴尺寸減小，過(guò)渡頻率增大；對(duì)比分析了立向上焊和立向下焊時(shí)工藝參數(shù)對(duì)電弧形態(tài)及熔滴過(guò)渡方式的影響規(guī)律，給出了兩種工藝下焊縫成形出現(xiàn)明顯差異的原因。 （4）從力的角度揭示了立向上焊和立向下焊焊接工藝和焊縫成形存在較大差異的本質(zhì)原因，結(jié)合不同焊槍傾角下采集到的熔滴過(guò)渡圖像，分析了立向上焊和立向下焊時(shí)熔滴與熔池的力學(xué)行為。
[Abstract]:In recent years, as the equipment of pressure vessel, nuclear power, marine engineering and oil and gas pipeline industry is becoming more and more heavy, the application of thick plate and thick pipe welding structure is becoming more and more extensive, and the demand for narrow gap all position welding is greatly increased. As an important part of all position welding, vertical welding is affected by gravity, if the selection of process parameters is improper. It is easy to weld down the weld pool and cause poor weld formation.
In order to solve the problem of side wall fusion in narrow gap welding and ensure the welding quality and production efficiency of vertical welding joint, a small arc narrow gap welding torch is designed. The influence of process parameters on welding stability and weld formation is explored, and the best process parameters for vertical and vertical welding are determined. On this basis, a single channel multi layer welding test of thick plate has been completed, and a vertical welding joint without macroscopic defects is obtained. By using high speed camera technology, the form of droplet transition and arc, and the behavior of the molten pool are compared and analyzed. The behavior of the molten pool is good for the future realization of the full position welding of the narrow gap between the wobble arc and the thick wall pipe. Prepare.
(1) first, the circuit system, water cooling system and gas protection system of the welding torch are designed and optimized. The experimental results show that the torch has stable performance and is suitable for long time welding work.
(2) the effects of protecting gas flow, welding current, welding speed, swing angle, swing frequency and the residence time of side wall on the weld forming are studied, and the forming characteristics and causes of vertical and vertical downward welding weld under different process parameters are preliminarily analyzed. The 25mm thick Q235 steel is carried out. Vertical and vertical welding tests were carried out and vertical weld joints without macroscopic defects were obtained.
(3) the arc behavior and droplet transition of the narrow gap GMAW of the oscillating arc are observed by high speed camera technology. The influence of the swing on the arc shape and droplet transition in narrow gap welding is studied. It is found that the arc and droplets all deviate from the wire axis due to the centrifugal force, and the droplet size decreases and the transition frequency increases. The influence of process parameters on the shape of arc and the mode of droplet transition is analyzed, and the reasons for the obvious difference in the weld formation under the two processes are given.
(4) from the angle of force, the essential reasons for the large difference between the vertical and vertical welding process and the weld formation are revealed, and the mechanical behavior of the droplets and the molten pool is analyzed by combining the droplet transition images collected under the different angle of the welding torch.

【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TG434.5;TG44

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