MIG

MIG Technique
GMAW (Gas Metal Arc Welding) and MIG (Metal Inert Gas) welders require basic techniques. The position of the welding torch, angle of work, speed of feeding electrode, voltages and direction of welding are important welding parameters for a good weld beat. MIG / GMAW welders are perfect to produce good weld.

MIG Resources

MIG (GMAW) Welding Technique

MIG or GMAW is a relatively simple welding technique. This is because the operator of the welder is feeding the consumable wire automatically. The automatic feed allows the operator to only guide the welding gun. Despite the operational simplicity, GMAW welding does require practice and certain amount of knowledge.

Each MIG / GMAW welding machine is different. Before welding is started, machine must be setup properly. The testing is often done on the scrub metal and requires trial and error. Nevertheless, operators are required to consult data specifications for each welding machine.

The important factor in Gas Metal Arc Welding is consistency and the proper stickout distance. The stickout distance is the electrode extension (or length of filler wire exposed from the nozzle).

Arc welding in general are susceptible to poor technique. Practice is vital for good results.

MIG / GMAW Welding Gun Position

The stickout or the length of the electrode wire should be between 6mm to 13mm. This applies to most applications. The MIG / GMAW welder should use 2 hands to guide the welding torch/gun. This improves stability and quality of the weld.

Metal Inert Gas or Gas Metal Arc Welding is susceptible to oxygen and nitrogen contamination. Any loss, obstruction or dispersion of shielded gas will result in dross and porosity.

The right hand diagram summarises holding techniques of the welding torch/gun. This ensures good gas shielding of electrode and smooth regular weld profile.
Therefore for groove weld:

• The work angle of the end view (looking en-face to the weld) is 90 degrees
• The gun angle of the side view (looking sideways) is 0-15 degrees

or fillet weld:

• The gun angle of the side view (looking sideways) is 0-15 degrees
• The gun angle to the vertical and horizontal plates is 45 degrees

MIG / GMAW Weld Beat Shape

It is obvious that good welding starts with the basic weld beat. Gas Metal Arc Welding is not an exception. With MIG / GMAW weld beat shape is determined by gun angle, direction of travel, electrode stickout, speed of wire feed, voltage and current.

As a rule of thumb the optimal performance of MIG / GMAW is achieved when:

• Gun angle is between 10 and 15 degrees for groove and 40-45 degrees for fillet weld
• The stickout of filler wire is between 6mm and 13mm
• Settings of voltage and current (wire feed speed) follow manufacturer data
• Welding gun/torch is pushed rather then pulled from the welding pool

With MIG / GMAW weld beat shape is determined by gun angle, direction of travel, electrode stickout, speed of wire feed, voltage and current.

MIG / GMAW Butt or Groove Joint Overview

1. Groove or Butt Joint
2. Side View of Welded Metal
3. Front View of Welded Metal

MIG / GMAW Fillet Joint Overview

1. Vertical Plate
2. Horizontal Plate
3. Fillet Weld

MIG / GMAW Weld Beat Overview

1. Gun travel speed slow
2. Gun travel speed normal
3. Gun travel speed fast
4. Filler weld electrode (stickout) short
5. Filler weld electrode (stickout) normal
6. Filler weld electrode (stickout) long