TIG welding (argon tungsten arc welding) is a welding method using pure Ar as the shielding gas and tungsten electrode as the electrode. TIG welding wires are supplied in a straight strip of a certain length (usually lm).
"Inert gas arc welding using pure tungsten or activated tungsten (thorium tungsten, cerium tungsten, zirconium tungsten, lanthanum tungsten) as non fusible electrodes, using the arc between the tungsten electrode and the workpiece to melt the metal to form a weld.".
During welding, the tungsten electrode does not melt and only acts as an electrode. At the same time, argon or helium is fed into the nozzle of the welding torch for protection. Additional metal can also be added as needed. Internationally known as TIG welding.
advantage
The main advantage of TIG welding is that it can weld a wide range of materials, including workpieces with a thickness of 0.6 mm or more, including alloy steel, aluminum, magnesium, copper and its alloys, gray cast iron, various bronze, nickel, silver, titanium, and lead.
The main application area is to weld thin and medium thickness workpieces, which are used as root passes on thicker sections.
MIG welding is a welding method that uses inert gases such as Ar as the main shielding gas, including pure Ar or Ar gas mixed with a small amount of active gas (such as less than 2% O2 or less than 5% CO2 gas) for MIG welding. MIG welding wires are supplied in coils or coils by layer winding.
This welding method uses the arc that burns between the continuously fed welding wire and the workpiece as a heat source, and the gas emitted by the welding torch nozzle protects the arc for welding.
advantage
Convenient for welding at various positions, but also with faster welding speed and higher deposition rate.
MIG welding is suitable for welding most major metals, including carbon steel and alloy steel. MIG arc welding is suitable for stainless steel, aluminum, magnesium, copper, titanium, picks, and nickel alloys. This welding method can also be used for arc spot welding.
matters needing attention
TIG welding
A. Shielding gas flow requirements: 7-12 L/min when the welding current is between 100-200 A When the welding current is between 200-300A, 12-15L/min is appropriate.
B. The extension length of the tungsten electrode relative to the nozzle should be as short as possible, and the arc length should be generally controlled at 1-4 mm (2-4 mm for welding carbon steel; 1-3 mm for welding low alloy steel and stainless steel);
C. Wind prevention measures shall be taken when the wind speed is greater than 1.0m/s; Pay attention to ventilation to avoid injury to the operator;
D. During welding, strictly remove impurities such as oil, rust, and moisture from the welding area.
E. It is recommended to use a DC power supply with steep external characteristics, with tungsten electrode as the positive electrode.
F. When welding low alloy steel with a content of 1.25% Cr or higher, the back surface should also be protected.
MIG welding
A. The protective gas flow rate should be 20-25 L/min;
B. The arc length is generally controlled at about 4-6 mm;
C. The impact of wind is particularly detrimental to welding, and wind prevention measures should be taken when the wind speed is greater than 0.5m/s; Pay attention to ventilation to avoid injury to the operator;
D. Using pulse arc current, stable spray arc can be obtained, especially suitable for welding stainless steel, thin plate, vertical welding, surfacing welding;
E. Please use Ar+2% O2 gas combination welding for ultra low carbon stainless steel, and do not use Ar and CO2 mixed welding steel;
F. During welding, strictly remove impurities such as oil, rust, and moisture from the welding area.
