Study On New Push&Pull CO₂ Welding Technics

With the development of modern manufacturing, sheet metal welding has become an important question for discussion in welding field. CO2 welding has been widely used when it came out due to the advantages of high efficiency, low cost and so on. In the result of transferring droplet in a higher current, CO2 welding can not reduce the energy input effectively, and this restrict the application in sheet metal welding. The push and pull short-circuit CO2 welding transfers the droplet by pulling the wire, which can reduce the energy input effectively. Therefor, the research presented here is concentrating on the push and pull short-circuit CO2 welding technics.From the point of view of energy distribution, the influence of different welding parameters on the push and pull short-circuit CO2 welding process is analyzed, which lays the foundation for the low energy push and pull short-circuit CO2 welding process.In the traditional short-circuit CO2 welding process, the proportion of short time and arc time is an important factor which influence the energy distribution in the weling process. In manner of expanding early short time, the influence on the welding process is analyzed. As is indicated from the result, when early short time is expanded, the short time is expanded. As the arc time is shorten, energy of arc period decreases, and energy of short-circuit decreases too, while the reduction is minor.Energy of short period acts mainly on wire,while that of arc period acts both on wire and base metal. In manner of changing the current in late short period and the voltage in early arc period, we change the energy distribution between wire and base metal. As is indicated from the result, with the increase of current in the late short period and the decrease of voltage in the early arc period, energy input to the base metal declines, and so is in the welding process. So we can accomplish the low energy welding process.The influence of short-circuit frequency is analyzed. As is indicated from the result, raising the short-circuit frequency can increase the energy input to base metal, so is the total energy input.In comparison with traditional short-circuit CO2 welding technics, we can see that push and pull short-circuit CO2 welding technics can accomplish lower energy welding process. In the welding process, energy distributes uniformly, the shape of wire line is good. Therefore, push and pull short-circuit CO2 welding technics is fit for thin sheet metal welding.