| CO2 gas shielded arc welding is one of the most widely welding methods with many advantages, such as low cost, anti-greasy, little deformation, high efficiency, easy to automate and so on, it can be also used for all position welding. In the process of welding, wires are melted by electric arc thermal, forming droplets. Under the action of gravity,surface tension, electromagnetic pinch force, droplets make irregular movement around the wire end. Meanwhile, CO2 welding electric arc makes a shock with it. Shock arc will make directly influence on temperature filed and flow filed of weld pool. The thesis mainly studied the effects of irregular movement electric arc on weld pool.Previous studies about electric arc shock and characteristics of weld pool flowing were fewer, also didn’t consider the heat taken by droplet transition into weld pool. In this thesis, new heat source model was established, namely bouncing electric arc heat model,at the same time considered droplet heat. On this basis, the control equation and boundary condition were given. By GAMBIT established the physical model,reasonable divided grid, selected low-carbon steel(Q235) as material and made simulations of temperature filed and flow field of weld pool on bouncing electric arc by fluent. At last, analysis research was made with the help of Tecplot software.At the welding speed of 0.005m/s, different currents were selected,welded the low-carbon steel(Q235) used CO2 gas shield welding,simulated the temperature field and flow field of weld pool under the condition of stable electric arc and bouncing electric arc. The forming process of weld pool under two kinds of electric arc were analyzed, made the analysis of temperature field and flow field in detail. |
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