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.
The difference between mixed gas shielded welding and pure CO2 shielded welding is that the welding is conducted by using the gas mixture of O2 and CO2, Ar and CO2, or O2 and Ar and CO2 in different proportions as the shielding gas, referred to as MAG-M welding. Compared with pure CO2 gas shielded welding, mixed gas shielded welding has the following advantages:
Welding wire with diameter of 1.2mm is used for small welding spatter. When welding current is 350A, mixed gas of Ar and CO2 is used as protection gas.
Gas-electric vertical welding is a new method of GAS arc welding developed from conventional gas arc welding and electroslag welding. The shielding gas can be a single gas (e.g., CO2) or a mixture of gases (e.g., Ar+CO2). Welding wires can be solid cored or flux cored.
In the welding process, a water-cooled slider is used to block the molten metal and force it into shape to achieve the vertical position of welding. The advantages of gas-electric vertical welding are: even the thick plate with i-shaped groove can be formed by welding at one time, and the production efficiency is quite high. Usually used for welding 12~80mm thick low carbon steel plate or medium carbon plate, also can weld austenitic stainless steel plate and other metal alloys.
The welding power source of gas-electric vertical welding adopts dc power reverse connection method. When using the external characteristics of steep drop, the walking mechanism can be controlled through the feedback of arc voltage to keep the stability of the welding wire extension length. When the flat characteristic is adopted, the automatic lifting of the walking mechanism can be controlled by manual control or by detecting the rising height of the molten pool. The capacity of welding power supply for gas-electric vertical welding should be large, and the load persistence rate should be high. The usual welding current is 450~650A, and the maximum welding current is 1000A, and the load persistence rate is 100%
Gas-electric vertical welding equipment is mainly composed of welding power supply, welding gun, wire feeding mechanism, water-cooled slider, air feeding system, welding gun swing mechanism, lifting mechanism, control device and so on. Except for the welding power supply, the rest are assembled together and move vertically upward as the welding process goes on. This method looks like the axis of the weld is in a vertical position, but in fact it is a horizontal welding of the weld in vertical rise, because the welding wire is constantly sent down.