Flux-cored wire arc welding
Today, I want to introduce to you another type of arc welding-flux-cored wire arc welding. It is the same as ordinary molten electrode gas shielded welding, which uses a fusible flux-cored wire as one electrode (usually connected to the positive electrode, that is, DC reverse connection), and the base material as the other electrode. Usually a mixture of pure CO2 or CO2 + Ar is used as the protective gas. The main difference from ordinary molten electrode gas shielded welding lies in the powder mixture inside the welding wire. During welding, metallurgy occurs between the powder mixture, welding wire metal, base metal and protective gas that melt under the action of arc heat, and a thin layer of liquid slag is formed to cover the molten droplets and cover the molten pool. The metal forms another layer of protection. In essence, this welding method is a method of combined slag protection.
Flux-cored wire arc welding combines the advantages of manual arc welding and ordinary molten electrode gas shielded welding. Using this welding method, you can:
(1) Adopting the combined protection of gas and slag, the welding seam is beautifully formed, the arc stability is good, the spatter is small and the particles are fine.
(2) The welding wire has a fast deposition speed (the deposition efficiency is about 85% -90%) and the productivity is higher (the productivity is about 3-5 times higher than manual welding).
(3) It has strong adaptability for welding various steel materials to better achieve customized production. By adjusting the composition or proportion of the powder, the required chemical composition of the weld metal can be provided.
(4) High degree of automation (compared with electrode), suitable for automatic welding, semi-automatic welding or fully automatic welding.
(5) The welding utilization rate is high (compared with the electrode), and the utilization rate of the welding wire is far more than that of the welding electrode. Under the same weight, the welding wire is more cost-effective than the welding electrode.
Everything has advantages and disadvantages. Although flux-cored arc welding has many advantages, there are also complex welding wire manufacturing processes; in addition, there are disadvantages such as the appearance of the welding wire is easy to rust, and the powder is easy to absorb moisture. Therefore, the use of this welding method requires strict management of the preservation of the welding wire.
Different welding wires and shielding gas can be used to perform all-position welding such as flat welding, horizontal welding, and overhead welding. Compared with ordinary molten electrode gas shielded welding, shorter dry extension (wire extension length) and larger welding current can be used. Compared with manual arc welding, when welding fillet welds, welds with larger fillet sizes can be obtained.
Flux-cored arc welding is commonly used for surfacing welding of carbon steel, alloy steel, stainless steel, and steel surfaces. Due to the above characteristics, flux-cored wire arc welding in steel welding is the most promising welding method to replace ordinary hand arc welding to achieve automatic and semi-automatic welding.