本文選題：雙絲氣保焊 + 纜式焊絲　； 參考：《江蘇科技大學》2017年碩士論文

【摘要】：近年來,在海洋工程、油氣管道、壓力容器及船舶制造等行業(yè)中焊接工作量有了大幅度的增加,傳統(tǒng)焊接方法難以滿足日益增加的焊接生產(chǎn)需求。在保證焊接質(zhì)量的前提下,提高焊接生產(chǎn)效率成為了焊接工作者的主要研究方向,本文研究的窄間隙雙纜式GMAW焊接技術就是在這種大環(huán)境下發(fā)展起來的。本研究主要研究Q235鋼厚板的雙纜式GMAW焊接,以纜式焊絲作為填充材料,用GAMBIT軟件建立合適的數(shù)學模型,基于FLUENT和UDF的二次開發(fā),考慮相變潛熱、材料熱物理性能等問題,對雙纜式GMAW堆焊和窄間隙雙纜式GMAW焊熔池溫度場及流場進行模擬計算。為了驗證所建模型的準確性,分別采用紅外熱像儀測溫和焊縫宏觀金相驗證了模擬仿真結果,對模擬結果進行了試驗驗證。建立了雙纜式GMAW焊三維數(shù)值模型,對雙纜式GMAW焊熔池溫度場和流場的演變過程進行了模擬計算。研究結果表明,隨著焊接過程的進行,熔池逐漸長大,熔池內(nèi)部溫度逐漸升高,并且流動加劇,溫度場和流場分布范圍隨之增大,熔池前端等溫線分布較為密集,溫度梯度大,熔池后端等溫線分布較為稀疏,溫度梯度較小。并將模擬結果與普通單絲氣保焊的熔池溫度場及流場進行對比分析,和傳統(tǒng)單絲氣保焊相比,雙纜式GMAW焊具有加熱范圍大、保溫時間長、熔敷速度快等特點,能夠有效解決傳統(tǒng)單絲氣保焊加熱過于集中、焊接熔池過熱、熔敷效率低等問題。研究不同焊接工藝參數(shù)對雙纜式GMAW焊接過程中熔池溫度場和流場的影響。研究表明,在其它焊接參數(shù)保持不變的前提下,熔池溫度場和流場分布范圍隨著焊接電流的增大而增大,熔池最高溫度和最大流速也隨著焊接電流的增大而增大,總電流為400A、500A和600A時熔池最高溫度分別為2377K、2514K和2726K,熔池最大流速分別為9.1cm/s、10.3cm/s和12.6cm/s;當焊接速度不斷增加時,熔池溫度場和流場分布范圍則隨之減小,熔池內(nèi)部最高溫度和最大流速也隨之減小,焊接速度為600mm/min、900mm/min和1200mm/min時熔池最高溫度分別為2810K、2726K和2569K,熔池最大流速分別為13.9cm/s、12.6cm/s和11.5cm/s。研究了不同前后絲電流下的焊接熔池溫度場及流場,對比得出較大的前絲電流有利于焊縫的鋪展。研究不同焊接工藝參數(shù)對窄間隙雙纜式GMAW焊接過程中熔池溫度場和流場的影響,其變化規(guī)律和雙纜式GMAW焊的變化規(guī)律基本相同。隨著間隙的增大,熔池溫度場和流場分布范圍隨之減小,最高溫度和最大流速也隨之減小,間隙為14mm、16mm和18mm下熔池最高溫度分別為3219K、3134K和3022K,熔池最大流速分別為14.1cm/s、13.4cm/s和12.6cm/s;隨著雙絲間距的增大,熔池溫度場和流場分布范圍隨之減小,最高溫度隨之增大,最大流速隨之減小,雙絲間距間距為10mm、15mm和20mm下熔池最高溫度分別為3134K、3209K和3279K,熔池最大流速分別為13.4cm/s、12.6cm/s和11.7cm/s;隨著雙絲偏移量的增加,熔池溫度場分布范圍減小,最高溫度也隨之減小,雙絲偏移間距為0mm、2mm和4mm下熔池最高溫度分別為3134K、2997K和2904K。研究了脈沖電流下的窄間隙雙纜式GMAW焊熔池溫度場和流場分布規(guī)律,得出一脈沖加一普通電流為最佳組合。驗證了模擬結果的準確性,證明了本研究所建計算模型的可靠性。
[Abstract]:In recent years, the workload of welding in marine engineering, oil and gas pipeline, pressure vessel and shipbuilding industry has been greatly increased. The traditional welding method is difficult to meet the increasing demand of welding production. In the premise of ensuring the quality of welding, the improvement of welding production efficiency is the main research direction of the welding workers. The narrow gap double cable GMAW welding technology is developed in this big environment. This study mainly studies the double cable type GMAW welding of the thick Q235 steel plate. The cable type welding wire is used as filling material and the GAMBIT software is used to establish the appropriate mathematical model. Based on the two development of FLUENT and UDF, the latent heat of phase change and the thermal physical properties of the material are considered. The temperature field and flow field of double cable type GMAW surfacing and narrow gap double cable type GMAW welding pool are simulated. In order to verify the accuracy of the model, the simulation results are verified by infrared thermograph temperature measurement and weld macroscopic metallography, and the simulation results are verified. A three dimensional numerical model of double cable type GMAW welding is established. The temperature field and the evolution process of the flow field of the cable type GMAW weld pool are simulated. The results show that, with the process of welding, the molten pool grows up gradually, the temperature in the molten pool increases gradually, and the flow is intensified. The distribution range of temperature field and flow field increases, the distribution of the isothermal line in the front end of the molten pool is more dense, the temperature gradient is large and the molten pool is after the pool. The distribution of the end isotherm is relatively sparse and the temperature gradient is small. Compared the simulation results with the temperature field and flow field of the weld pool of ordinary monofilament welding, compared with the traditional monofilament gas shielded welding, the double cable GMAW welding has a large heating range, long heat preservation time and fast melting speed, which can effectively solve the traditional monofilament welding heat welding heating too much. The influence of different welding parameters on the temperature field and flow field of the molten pool during the double cable GMAW welding process is studied. The study shows that the temperature field and the flow field distribution of the molten pool increase with the increase of the welding current, and the highest temperature of the pool and the maximum temperature of the molten pool. The maximum flow velocity increases with the increase of welding current, the total current is 400A, the maximum temperature of the pool is 2377K, 2514K and 2726K at 500A and 600A. The maximum flow velocity of the pool is 9.1cm/s, 10.3cm/s and 12.6cm/s respectively. When the welding speed is increasing, the temperature field and the distribution range of the flow field are reduced, and the highest temperature and the most temperature in the molten pool are found. The maximum flow velocity also decreases with the welding speed of 600mm/min, 900mm/min and 1200mm/min, the maximum temperature of the pool is 2810K, 2726K and 2569K respectively. The maximum flow velocity of the molten pool is 13.9cm/s, 12.6cm/s and 11.5cm/s. respectively, and the welding pool temperature field and flow field under different wire current are studied, and the comparison shows that the larger front wire current is beneficial to the weld. The influence of different welding parameters on the temperature field and flow field of the weld pool during the narrow gap double cable GMAW welding process is studied. The variation law of the weld pool and the double cable type GMAW welding are basically the same. With the increase of the gap, the temperature field and the distribution range of the flow field decrease, the maximum temperature and the maximum flow velocity also decrease, the gap is 14mm, 1 The maximum temperature of molten pool in 6mm and 18mm is 3219K, 3134K and 3022K respectively, and the maximum flow velocity of molten pool is 14.1cm/s, 13.4cm/s and 12.6cm/s, respectively. With the increase of double wire spacing, the temperature field and the distribution range of flow field decrease, the maximum temperature increases, the maximum velocity decreases, the distance between the two wires is 10mm, and the molten pool in 15mm and 20mm is the most high temperature. The maximum flow velocity of the molten pool is 13.4cm/s, 12.6cm/s and 11.7cm/s, respectively 3134K, 3209K and 3279K. With the increase of the double wire offset, the distribution range of the melting pool temperature field decreases, the maximum temperature decreases, the offset distance of the double wire is 0mm, the maximum temperature of the molten pool under 2mm and 4mm is 3134K, 2997K and 2904K. have studied the narrow gap between the pulse current. The temperature field and the distribution of the flow field in the weld pool of double cable type GMAW welding are obtained. The optimum combination of a pulse plus a common current is obtained. The accuracy of the simulation results is verified, and the reliability of the calculated model is proved.
【學位授予單位】：江蘇科技大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TG457.11

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本文編號：1901441