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Welding

TIG and MIG torch parts

In short

The name and job of every part, and what wears out.

TIG torch

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Principle section, air-cooled.
  1. 1Tungsten electrode: carries the arc. Wears.
  2. 2Ceramic cup: guides gas around the electrode. Wears.
  3. 3Collet body or gas-lens body: carries current and gas.
  4. 4Collet: clamps the electrode, sized to its exact diameter.
  5. 5Head: carries current, removes heat.
  6. 6Back cap: locks the collet; short or long.
  7. 7Handle: insulates, holds the switch.
  8. 8Cable assembly: power cable, gas hose, control lead.
  • Gas lens

    A screen at the end of the body makes the gas flow even: the electrode can stick out further and the pool is better covered (stainless, titanium, corners).

MIG-MAG gun

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Principle section, air-cooled.
  1. 1Nozzle: directs gas, shields from spatter. Wears.
  2. 2Contact tip: passes current to the wire, sized to the wire. Wears.
  3. 3Diffuser: holds the tip, spreads the gas. Wears.
  4. 4Insulator: separates the nozzle from live parts.
  5. 5Neck: places the arc on the joint.
  6. 6Trigger.
  7. 7Handle.
  8. 8Liner: guides the wire from the feeder. Wears.
  9. 9Connector: power, gas, wire and control to the machine.

Before replacing a part

Note the exact torch model, cooling (air or water) and the electrode or wire diameter: two parts that look alike do not always fit.

Sources

  • WelderFacts : pièces d’une torche TIG : Chaîne des pièces, rôles, compatibilité (link)
  • Miller : fonctionnement d’un poste TIG: Torche refroidie par air (link)
  • Bernard : anatomie d’un pistolet MIG : Neuf pièces et leurs défaillances (link)

Updated · Publisher: The Level Code

Tools · Welding

Heat inputHeat input in kJ/mm (EN 1011-1) from current, voltage and travel speed.Carbon equivalent and preheatCE (IIW), CET and indicative preheat temperature (EN 1011-2, method B) with validity range check.Shielding gasRecommended gas (ISO 14175 class) and flow in L/min by process, material and wire diameter.Back purgeVolume to purge between dams, pre-purge time and gas use to shield the root side.Welding settingsCurrent, voltage, wire or electrode, gas and polarity by process, material, thickness and position; dimensioned joint preparation and passes.Weld shrinkageIndicative transverse and longitudinal shrinkage of a butt joint, with pre-setting advice.Filler metal weightJoint section (V, X, fillet), deposited weight and filler weight to order by process.Weld defect diagnosisTick what you see at the arc, in the pool and on the bead: ranked likely causes and remedies (TWI).ISO 5817 criteriaPermitted limit of an imperfection by quality level B, C or D, and verdict on the measurement (ISO 5817:2023).Weld pass layoutGroove area, number of layers and passes, numbered welding sequence sketch.Dissimilar metal weldingFiller metal to join two different metals (steel, stainless, duplex, nickel, aluminium) and precautions.