本文選題：電弧特性 + 縱向磁場��； 參考：《沈陽工業(yè)大學(xué)》2015年碩士論文

【摘要】：TIG焊因焊接性良好，無飛濺等優(yōu)點，被廣泛應(yīng)用于核電站及航空航天等重要領(lǐng)域。但TIG焊電弧能量分散，電弧力小以及鎢極受許用電流的影響，導(dǎo)致焊縫熔深淺，限制了該焊接方法在中厚板以及高效化方面的應(yīng)用。 本文在TIG焊電弧周圍施加縱向磁場，以改變電弧特性，提高電弧能量密度，從而增大焊縫熔深，進(jìn)而實現(xiàn)高效化及高質(zhì)量焊接。本課題將低頻、高頻磁場結(jié)合，研究了磁場頻率的變化對焊接電弧特性影響規(guī)律；利用高速攝像裝置對TIG焊電弧形態(tài)進(jìn)行拍攝；利用自制水冷銅陽極測試電弧壓力徑向分布；利用自制環(huán)形同心分裂陽極裝置測試電弧熱量分布；采用探針法測試電弧電流密度徑向分布。通過測試不同磁場頻率作用下電弧壓力、電流密度及電弧熱量分布等特性，并與傳統(tǒng)TIG電弧特性進(jìn)行對比，從而得到了磁控TIG焊的最佳焊接磁場參數(shù)。 實驗結(jié)果表明：焊材為銅板時，且外加直流或低頻磁場作用下，電弧形態(tài)由錐形變?yōu)殓娬中�；電弧壓力分布由正態(tài)分布變?yōu)榄h(huán)形雙峰分布，隨著磁場頻率的提高，環(huán)形雙峰奇異消失；電流密度分布與電弧壓力具有相同變化特征。在外加高頻磁場作用下，電弧形態(tài)由鐘罩型變?yōu)橹�；電弧中心壓力與傳統(tǒng)電弧壓力相比大幅提高；電流密度分布與電弧壓力具有相同變化特征。焊接電流有效值為70A，磁感應(yīng)強度為30mT，磁場頻率為1200Hz左右時，穩(wěn)定燃燒的TIG焊接電弧高速旋轉(zhuǎn)的旋轉(zhuǎn)半徑最小，電弧中心壓力從自由電弧時的0.29KPa增大為0.44KPa，，熱量分布系數(shù)從自由電弧時的34.5%升高到52.9%，電流密度由18A/mm2提高到50.2A/mm2。高頻磁場作用下的焊接電弧產(chǎn)生了磁壓縮現(xiàn)象。
[Abstract]:TIG welding is widely used in nuclear power plants, aerospace and other important fields because of its good weldability and no spatter. However, TIG welding arc energy is dispersed, arc force is small and tungsten electrode is affected by allowable current, which leads to shallow weld melting depth, which limits the application of this welding method in medium and thick plate and high efficiency. In this paper, the longitudinal magnetic field is applied around the arc of TIG welding to change the characteristics of the arc and increase the energy density of the arc, so as to increase the weld penetration and achieve high efficiency and high quality welding. In this paper, we combine low frequency and high frequency magnetic field to study the influence of magnetic field frequency on welding arc characteristics; use high speed camera to photograph TIG welding arc shape; use self-made water-cooled copper anode to test arc pressure radial distribution; The arc heat distribution was measured by a self-made ring concentric split anode device, and the radial distribution of arc current density was measured by the probe method. By measuring the characteristics of arc pressure, current density and arc heat distribution under different magnetic field frequencies, and comparing with the traditional TIG arc characteristics, the optimum magnetic field parameters of magnetically controlled TIG welding are obtained. The experimental results show that the arc shape changes from conical to bell cover when the welding material is copper plate and the applied DC or low frequency magnetic field is applied, the arc pressure distribution changes from normal distribution to circular double peak distribution, and with the increase of magnetic field frequency, the arc shape changes from normal distribution to annular bimodal distribution. The annular bimodal singularity disappears, and the current density distribution has the same characteristics as the arc pressure. Under the action of high frequency magnetic field, the arc shape changed from bell-shaped to cylindrical, the central pressure of arc increased significantly compared with the traditional arc pressure, and the current density distribution and arc pressure had the same change characteristics. When the effective value of welding current is 70A, the magnetic induction intensity is 30mTand the frequency of magnetic field is about 1200Hz, the arc rotation radius of stable combustion TIG welding arc at high speed is the smallest. The central pressure of the arc increases from 0.29 KPA to 0.44 KPA, the heat distribution coefficient increases from 34.5% to 52.9, and the current density increases from 18A/mm2 to 50.2 A / mm2. The welding arc under the action of high frequency magnetic field produces the phenomenon of magnetic compression.
【學(xué)位授予單位】：沈陽工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TG444.74

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本文編號：2111234