MIG MAG Welding: Parameters, Process, and Advantages

Posted on Mar 13, 2025 in Electromechanical Engineering

Welding Parameters

Current Polarity: Continuous current is used. Connect the electrode to the positive pole, which allows for a stable electric arc.

Wire Diameter: Smaller diameter wires are typically selected for smaller projects and repairs.

Voltage-Wire Speed: To obtain a stable arc, it is essential to regulate the voltage-wire speed. The regulation depends on the thickness to be welded and the diameter of the wire used.

Intensity: The intensity depends on the wire-feed speed and the thickness to be welded.

Protective Gas: Influences the form of the weld bead, penetration, appearance, and tendency for splashes.

MIG/MAG Equipment Components

  • Power Source: Consists of a transformer and a rectifier.
  • Wire Feeding Unit: Includes a wire reel mounted on a shaft with adjustable braking, a drive motor, and two rollers. One roller has a slot to guide the wire, and the other advances the wire.
  • Shielding Gas Circuit: Composed of a shielding gas bottle coupled to the machine, a pressure regulator, a flowmeter to regulate gas pressure, and a solenoid valve to control gas passage.
  • Welding Gun: Features a button and two nozzles. The outer nozzle channels gas into the welding zone, and the inner nozzle provides electrical contact for the wire.
  • Hose: Connects the welding gun to the machine, allowing the flow of filler material, current, and gas.
  • Regulation and Control Elements: Located on the front panel, these typically include controls for voltage, wire feed, and a welding time timer.

Advantages

Good resistance, easy to use in all areas and positions, fills any tolerances in the joints, high welding speed, low thermal influence, and reduced deformation.

Background

The process involves electric arc welding with direct current, where the arc is established between a continuous wire electrode and the workpiece. The weld pool is protected from the atmosphere by a gas that isolates it from oxygen and nitrogen, preventing porous welds. Depending on the nature of the gas, it is called:

  • MIG (Metal Inert Gas) – Inert gas protection.
  • MAG (Metal Active Gas) – Active gas protection.

Consumables

Filler Materials: Should be of the same nature as the base material. Select the appropriate roller guide according to the wire diameter to avoid marking the wire during feeding. For optimal preparation, a wire diameter of 0.6 mm is recommended.

Shielding Gases: Their mission is to form a protective layer over the weld pool, shielding it from oxygen and nitrogen. The most commonly used gas is a mixture of argon and carbon dioxide. Gases are identified using a color code.

Spot Welding

Used in the replacement of load-bearing parts of the bodywork. It consists of welding two sheets together. The top sheet is pre-drilled, and the weld is made through these holes to join it to the bottom sheet.

Work Recommendations

  • The execution of welding work is based on two aspects: the choice of consumables and the regulation of parameters.
  • The welding gun must maintain a correct position for the gas to conveniently protect the weld pool.
  • The preferred welding direction is from right to left.
  • Linear displacement of the gun is preferred.
  • During operations, ensure that the welding tube is not coiled to avoid hindering the wire’s progress.
  • Many of these machines have a built-in gun holder for carbon electrodes.