Simulation Of CO₂ Short Circuit Transfer With Simulink Based On Energy Balance

As one of CO₂ welding important transfer modes, short circuit transfer is always used for thin sheet welding of low carbon steel and low alloyed steel. However, there exist defects in CO₂ welding, such as large spatter and bad welding seam form. It needs more manpower, material resources and longer test cycle through experiment to research different parameters influences. The influence of some parameters is difficult or even cannot be test verification. Exploring mechanism of droplet short circuit transfer dynamic process through computer simulation model is an important branch of CO₂ welding research. The method can explore the influence of different loop parameters for welding process conveniently, thus optimize welding technology parameters.In this paper, through welding power system circuit model, considering enthalpy changes on the wire tip and energy balance of droplet, the more accurate CO₂ welding short circuit transfer dynamic process simulation model with MATLAB/Simulink was put forward and established, and the influence on welding process of different loop parameters?such as circuit inductance, droplet enthalpy, coefficient accounting for the enthalpy loss in the metal, sum of cathode and anode voltage, anode equivalent voltage and distance from contact tip to workpiece etc.? was simulated. Based on that, the reasons of the influence were analyzed, which provides theoretical basis for choosing suitable parameters during experiments. On the basis of analyzing influence of welding circuit parameters and choosing suitable circuit parameters, summarized electrical signals changes trend and contrast with practical of multiple characteristic parameters?such as peak current, valley current, short circuit time and arcing time etc.? during matching and mismatching welding parameters?power given voltage 20 V, wire feed rate 2.0m/min, 3.0m/min and 4.2m/min, respectively; wire feed rate 3.0m/min, power given voltage 19 V, 20 V and 22 V, respectively?, indicating the model can basically comprehensive coincide with practical. Thus provide reference for short circuit transfer welding technology chooses, and lays a foundation for other droplet transition mode simulation.