There are five kinds of CO2 gas shielded welding, such as hybrid gas shielded welding, gas electric vertical welding, CO2 gas shielded arc spot welding, solid cored wire CO2 gas shielded welding and flux cored wire CO2 gas shielded welding.
Flux cored wire is composed of steel belt and flux. The flux is placed on a special steel belt, which is cored and drawn by the coiling machine. The welding process that can be shielded by gas is called flux cored wire welding, and the CO2 gas welding that can be shielded by flux cored wire is called flux cored wire CO2 gas welding. In the welding process, flux-cored wire produces gas and slag under the action of high temperature of the arc, which plays the role of gas protection and slag protection. Without additional gas protection, it is called self-protecting flux-cored wire. This welding method is called self-protecting flux-cored wire welding.
The difference between this welding method and CO2 gas shielded welding is that flux cored wire is used instead of solid cored wire for welding, as shown in Figure 1-27.
Flux cored wire is made of thin steel plate rolled into a round steel tube or special-shaped steel tube, filled with a certain amount of powder, after drawing the wire, the role of powder in the welding process is the same as the electrode coating. Therefore, the welding process of flux cored wire gas shielded welding is double protection and gas slag combined protection, which can obtain higher welding quality. Figure 1-28 shows the cross section of a flux-cored welding wire.
Compared with solid cored CO2 gas shielded welding, flux cored CO2 gas shielded welding has the following disadvantages: