GMAW into inert gas welding (TIG welding and MIG welding), active gas welding (MAG welding), and self-protection welding. TIG welding with pure Ar, MIG welding commonly used Ar +2% O2 or Ar +5% CO2. MAG welding, the main use of CO2 gas. CO2 welding process in order to improve performance, but also can be CO2 + Ar or CO2 + Ar + O2 gas mixture or the use of  Welding Wire.
1, TIG welding wire
Sometimes TIG welding without filler wire, heating and melting the base metal being welded directly connected, and sometimes add filler wire, the shielding gas is pure Ar, no oxidation, wire melting does not change the basic ingredients, so the wire is welded components seam components. Some are used as the base metal composition wire elements, and thus consistent with the parent material composition of the weld. TIG welding, the welding energy is small, the weld strength and plastic, good toughness, easy to meet performance requirements.
2, MIG and MAG welding
Method is mainly used for MIG welding high-alloy stainless steel. In order to improve the arc characteristics in Ar gas by adding appropriate amount of O2 or CO2 gas, it becomes MAG method. Welded steel, the use of Ar +5% CO2 can increase the ability to weld porosity resistance. However, when welding low carbon stainless steel can not be used Ar +5% CO2 gas mixture, can be used only Ar +2% O2 gas mixture to prevent the weld by the carbon. Current MIG welding of low alloy steel is gradually being Ar +20% CO2 replaced by the MAG welding. MAG welding shielding gas because there is some oxidation, should increase the wire in the Si, Mn and other elements of the content of oxygen and other elements consistent with the base material can also be different. Welding of high strength steel, the weld C content is usually lower than the base metal, Mn content should be higher than the base metal, not only for oxygen, but also the requirements of the weld alloy composition. In order to improve low temperature toughness of the weld in the Si content should not be too high.
3, CO2 welding wire
CO2 is a reactive gas, with a strong oxidizing and therefore CO2 welding wire used must contain a high Mn, Si and other elements in oxygen. CO2 welding commonly used C-Mn-Si system wire, such as H08MnSiA, H08Mn2SiA, H04Mn2SiA and so on. CO2 welding wire diameter is usually 0.89 1.0 1.2 1.6 2.0mm and so on. ≤ 1.2mm diameter wire filaments are CO2 welding, wire diameter ≥ 1.6mm thick wire CO2 welding part.
H08Mn2SiA wire is a widely used CO2 welding wire, it has good process performance, suitable for welding low-alloy steel below the rank of 500Mpa. Requirements for higher strength level of steel should be used in wire composition contains Mo elements H10MnSiMo other brands of wire.
4, electroslag welding wire
Electroslag welding applied to the plate and thick plate welding. Electroslag welding wire from the main alloying metal and fill the role.
5, non-ferrous metals and iron wire
Grade the first two letters "HS", said non-ferrous metals and iron wire; grades in the first digit indicates the type of Aluminium Welding Wirecomposed of classical studies, grades in the second and third numbers indicate the same type wire of different grades.
(1) welding wire
Surfacing of the current production of carbide wire there are two categories: the high-chromium alloy cast iron (especially depending Thrallmar) and cobalt base (stellite) alloy. High-chromium cast iron alloy with good oxidation resistance and resistance to cavitation performance, high hardness, good wear resistance. The cobalt-based alloys in high temperature of 650 degrees, also to maintain a high hardness and good corrosion resistance. One low-carbon, low toughness of tungsten; carbon, high hardness of tungsten, but the impact is poor.
Carbide welding wire can be oxygen - acetylene gas welding methods such as welding, in which oxygen - acetylene welding although the production efficiency is low, but the equipment is simple, when the melting depth of surfacing, base metal melting less, high quality welding , because the more extensive application.
(2) of copper and copper alloy welding wire
Copper and copper alloy welding wire used in copper and copper alloy, brass wire which is also widely used in brazing carbon steel, cast iron and carbide cutting tools. Copper and copper alloy welding, using a variety of welding methods, the correct choice of filler metal is a necessary condition to obtain high-quality welds. Oxygen - acetylene gas welding should be used together with the welding flux.
(3) aluminum and aluminum alloy welding wire
Aluminum and aluminum alloy welding wire for welding aluminum and oxygen - acetylene gas welding made the filling material. The choice of welding wire according to the type of base metal, butt joints crack resistance, mechanical properties and corrosion resistance requirements into account. Under normal circumstances, the welding of aluminum and aluminum alloy components are used with the base material of the same or similar grade wire, so you can get a better corrosion resistance; but welding hot cracking tendency of large heat strengthened aluminum, select the main wire crack resistance from the start address, then the composition of welding wire and base metal vary widely.
(4) iron wire
Welding is mainly used for welding cast iron. As the oxygen - acetylene flame temperature (less than 3400 ℃) than the arc temperature (6000 ℃) is much lower, and hot to concentrate, more suitable for thin-walled castings of gray cast iron welding. Moreover, gas welding flame temperature is lower than the ball of the agent can reduce evaporation, helping to ensure access to ductile weld tissue. Welding wire with a ball of iron present mainly yttrium plus magnesium alloy and the two heavy rare earth-based, high boiling point as yttrium, anti-globalization recession stronger capacity than magnesium, is more conducive to ensure the weld ball, so the more recent applications and more.

Since the Flux Cored Welding Wire is no protection or shielding gas flux, arc welding can be carried out in order to obtain qualified weld wire, self-shielded flux cored wire is to as slag, gas-making, the role of oxygen in steel powder and metal powder within the skin or applied to the wire surface, arc welding under the action of powder into the slag and gas, slag and gas-making play a protective effect, without additional gas.
The self-shielded flux cored wire deposition efficiency was significantly higher than the electrode, the flexibility of field welding and wind better than gas shielded arc welding, usually welding under the four winds. Because no shielding gas, suitable for outdoor or high-altitude operations, it is used for the installation site and construction sites.
 Protect the wire from the plastic weld metal toughness is generally lower than the Types Of Welding Wire used shielding gas. Since the current is mainly used to protect low-carbon steel wire welded structures should not be used for welding high-strength steel and other important structures, in addition, self-shielded wire when welding smoke larger in the narrow space work should pay attention to enhance ventilation.