本文選題：K-PAW準穩(wěn)態(tài)過程　切入點：小孔　出處：《金屬學報》2016年07期 　論文類型：期刊論文

【摘要】：基于流體動力學原理,同時考慮電弧壓力、表面張力、電磁收縮力、浮力和重力等因素影響,建立了隨小孔深度增加熱力作用二次變化的三維瞬態(tài)計算模型.利用上部雙橢球體下部錐體的組合式體積熱源描述等離子電弧對焊接工件的熱作用,提出了可以維持小孔穩(wěn)定的"孔內(nèi)固體攪動式"計算方法.為了提高計算效率,建立了相對焊縫縱截面對稱的計算區(qū)域;計算過程利用流體體積函數(shù)(VOF)法追蹤小孔邊界,基于FLUENT軟件對穿孔型等離子弧準穩(wěn)態(tài)焊接過程進行了數(shù)值模擬,得到了準穩(wěn)態(tài)焊接過程中小孔、熔池及流場的動態(tài)變化行為,分析了穿孔型等離子弧焊接(K-PAW)準穩(wěn)態(tài)過程的穩(wěn)定性,探討了影響小孔穩(wěn)定的工藝因素,最后進行了計算模型的驗證實驗.結(jié)果表明,在設(shè)定的焊接工藝參數(shù)下,3.0 s之后焊接過程達到準穩(wěn)態(tài),準穩(wěn)態(tài)焊接過程中小孔前壁熔池較薄,平均厚度為0.6 mm,且小孔前壁有一定傾斜現(xiàn)象,使得背面小孔中心相對焊接中心向后偏移,焊接不同時刻偏移量在0.46~0.97 mm之間波動.在準穩(wěn)態(tài)焊接過程中熔池內(nèi)存在穩(wěn)定的逆時針渦流,計算所得的背面小孔寬度與實驗結(jié)果吻合良好.
[Abstract]:Based on the principle of hydrodynamics and considering the influence of arc pressure, surface tension, electromagnetic contraction force, buoyancy and gravity, etc. A three-dimensional transient model is established for the secondary variation of thermal action with the increase of hole depth. The combined volumetric heat source of the upper double ellipsoid and lower cone is used to describe the thermal effect of plasma arc on the welded workpiece. In order to improve the calculation efficiency, a symmetrical calculation area relative to the longitudinal section of the weld is established, and the fluid volume function (VOF) method is used to trace the pore boundary during the calculation. Based on FLUENT software, the numerical simulation of the quasi-steady welding process of perforated plasma arc is carried out, and the dynamic behavior of small holes, molten pool and flow field in the process of quasi-steady welding is obtained. The stability of K-PAW quasi-steady process in perforated plasma arc welding is analyzed, and the technological factors affecting the stability of the keyhole are discussed. Finally, the verification experiment of the calculation model is carried out. The results show that, The welding process reaches quasi-steady state after 3.0 s under the set welding process parameters. In the process of quasi-steady welding, the weld pool of the front wall of the small hole is thin, the average thickness is 0.6 mm, and the front wall of the small hole is inclined to a certain extent. The center of the back hole moves backward relative to the center of the welding, and the deviation at different times fluctuates between 0.46 mm and 0.97 mm. There is a steady counterclockwise eddy current in the molten pool during the quasi-steady welding process. The calculated width of the back hole is in good agreement with the experimental results.
【作者單位】： 北京工業(yè)大學機械工程與應(yīng)用電子技術(shù)學院汽車結(jié)構(gòu)部件先進制造技術(shù)教育部工程研究中心;江蘇科技大學江蘇省先進焊接技術(shù)重點實驗室;
【基金】：國家自然科學基金資助項目51205176~~
【分類號】：TG456.2
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本文編號：1637105