What Is TIG

TIG (Tungsten Inert Gas Welding) is a high-precision arc welding method that uses a non-consumable tungsten electrode as the electrode and is performed under the protection of an inert gas (such as argon or helium). The following section will explain its principles, equipment, process, advantages, disadvantages, and applications.

• Arc Generation: A voltage is applied between the tungsten electrode and the workpiece, forming a high-temperature arc (temperatures can reach over 6000℃), causing localized melting of the base material.
• Gas Protection: Inert gas (commonly argon) is ejected from the welding torch nozzle, covering the arc and the molten pool, isolating it from oxygen and nitrogen in the air, preventing oxidation and porosity.
• Fill Metal: Welding wire can be fed into the molten pool manually or automatically (or without welding wire, relying solely on the self-melting of the base material) to form the weld.

• Power Supply: DC or AC TIG power supply. DC is commonly used for stainless steel and copper, while AC is more suitable for metals with oxide layers on their surface, such as aluminum and magnesium.
• Welding Torch: Contains a tungsten electrode, gas nozzle, and insulated handle. Some welding torches have a water cooling system to prevent overheating.
• Gas Supply System: Gas cylinder, pressure reducing valve, flow meter to ensure a stable output of inert gas.
• Control System: Adjusts current, gas flow rate, pulse parameters (such as pulsed TIG), etc.

• Current Type and Amount: DC positive (electrode connected to negative) results in deep weld penetration; DC reverse (electrode connected to positive) or AC is used for cleaning the oxide film on aluminum surfaces; current range is typically 10A–300A.
• Tungsten Electrode Selection: Commonly used electrodes include pure tungsten, thorium tungsten, and cerium tungsten. Different electrodes have different electron emission capabilities and high-temperature resistance.
• Gas Flow Rate: Generally 8–15 L/min. Too high a flow rate will cause turbulence, while too low a flow rate will result in insufficient protection.
• Welding Speed ​​and Arc Length: Slow speed results in high heat input and easy deformation; excessive arc length leads to arc instability.

Advantages:

• Clean welds, no spatter, and aesthetically pleasing weld formation.
• Precise heat input control, suitable for thin plates (above 0.5mm) and high-alloy materials.
• Weldable materials: Stainless steel, aluminum, titanium, nickel alloys, copper, etc.

Disadvantages:

• Slower welding speed, lower production efficiency than MIG/MAG.
• Requires high operator skill, requiring hand coordination (one hand holding the welding torch, the other feeding the wire).
• Higher equipment cost, and strict requirements for gas purity.

• Aerospace: Engine components, fuel tanks, and other components requiring extremely high strength and airtightness.
• Automotive and Rail Transportation: Exhaust pipes, aluminum alloy car body frames.
• Chemical and Energy: Pipelines, pressure vessels, nuclear power plant piping.
• Precision Manufacturing: Medical devices, electronic components, food processing machinery.

• Arc Radiation: A dedicated welding mask (shield size ≥10) must be worn.
• Gas Leakage Risk: Regularly check gas lines and ensure proper ventilation in the workplace.
• Electric Shock Protection: Ensure equipment is properly grounded and avoid operation in damp environments.