What You Need to Know About MIG Welding (Part 1)

Date Posted:24 April 2023

MIG welding, which is also called Gas Metal Arc Welding or GMAW, is commonly used in the automotive, construction, and manufacturing industries. It involves the use of a welding gun that feeds a wire electrode while simultaneously releasing a shielding gas that can protect the weld pool from any atmospheric contamination.

MIG welding is a versatile process used to weld various metals such as stainless steel, aluminum, and carbon steel. It is also a popular choice among welders due to the ease of use and ability to produce high-quality welds in a short amount of time.

In this first part, we’re discussing the basics of MIG welding:

How MIG Welding Works

MIG welding produces an electric arc between the wire electrode and the metal being welded. The heat that's generated by the arc melts the wire and the base metal, fusing to form a weld. The shielding gas released from the welding gun protects the weld pool from atmospheric contamination, which can cause defects in the weld.

Features of a Weld

A good MIG weld should have a uniform bead with no porosity or cracks. The weld should also have good penetration, meaning the weld metal fuses with the base metal to create a strong joint. The appearance of the weld should be smooth and even, with no splatter or excess metal.

The Process of MIG Welding

To start a MIG weld, the operator must first prepare the metal by cleaning it of any dirt, rust, or oil. The MIG welding machine or gun is then positioned at the beginning of the weld joint, and the wire electrode is fed through the gun. The operator pulls the gun trigger, which releases the shielding gas and starts the electric arc.

The operator then moves the welding gun along the joint, maintaining a consistent distance between the gun and the metal. As the wire electrode melts, it is deposited onto the metal to form the weld. The operator must also control the speed of the weld and the amount of wire being fed through the gun to ensure a uniform weld.

Voltage and Polarity

The voltage and polarity used in MIG welding are important factors that affect the quality of the weld. Voltage refers to the amount of electrical power used to produce the arc. In contrast, polarity refers to the direction of the electrical current.

A higher voltage will produce a hotter arc, resulting in deeper penetration and faster welding speeds. However, it can also cause more spatter and a rougher appearance to the weld. Lower voltage settings produce a cooler arc, which can result in a smoother weld with less spatter.

Polarity is also crucial in MIG welding. The two types of polarity used are direct current electrode negative (DCEN) and direct current electrode positive (DCEP). DCEN is used for welding metals such as aluminum, while DCEP is used for welding metals such as carbon steel.

Conclusion

MIG welding is a popular welding process used in different industries due to its versatility and ease of use. It involves the use of a MIG welding machine or gun that feeds a wire electrode while releasing a shielding gas protecting the weld pool from atmospheric contamination. The process of MIG welding requires the operator to control the speed of the weld, the amount of wire being fed through the gun, and the voltage and polarity used to produce the arc.

In the second part of this post, we're focusing more on metal transfer modes, the types of metals that can be MIG-welded, and typical applications of MIG welding.

National Welding Supplies is a top supplier of welding equipment in Australia. We provide top-notch industrial tools and welding equipment to meet all your welding needs. Ask us about our MIG welding machine and other equipment!

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