Welding construction

MIG welding was developed in the 1940's and 60 years later the general principle is still very much the same. MIG welding uses an arc of electricity to create a short circuit between a continuously fed anode (+ the wire-fed welding gun) and a cathode ( - the metal being welded).

The heat produced by the short circuit, along with a non-reactive (hence inert) gas locally melts the metal and allows them to mix together. Once the heat is removed, the metal begins to cool and solidify, and forms a new piece of fused metal.

A few years ago the full name - Metal Inert Gas (MIG) welding was changed to Gas Metal Arc Welding (GMAW) but if you call it that most people won't know what the heck your talking about - the name MIG welding has certainly stuck.

MIG welding is useful because you can use it to weld many different types of metals: carbon steel, stainless steel, aluminum, magnesium, copper, nickel, silicon bronze and other alloys.

Here are some advantages to MIG welding:

* The ability to join a wide range of metals and thicknesses
* All-position welding capability
* A good weld bead
* A minimum of weld splatter
* Easy to learn

Here are some disadvantages of MIG welding:

* MIG welding can only be used on thin to medium thick metals
* The use of an inert gas makes this type of welding less portable than arc welding which requires no external source of shielding gas
* Produces a somewhat sloppier and less controlled weld as compared to TIG (Tungsten Inert Gas Welding)

welding

Weld requirements are determined in accordance with job specifications
Material is cleaned and prepared using appropriate tools and techniques in accordance with standard operating procedures
Welding equipment including cylinders and regulators are assembled and set up safely and correctly in accordance with standard operating procedures.
Welding tips, settings and consumables selected against job requirements, welding procedures, in accordance with standard operating procedures
Routine welding in this unit is intended to apply in a manufacturing or maintenance environment where welding is not required to meet National Standard/ISO or equivalent codes
and/or licensing requirements. Welding to National Standard/ISO is covered by Unit 5.21A (Weld using oxyacetylene welding process (OAW) fuel gas welding). The person would work
autonomously or within a team environment using predetermined standards of quality, safety, work and welding procedures. Materials welded may include low carbon steel, cast
iron, etc. Preparation of materials would be minimal and include preheating, setting up jigs, fixtures, clamps etc. Setting up may include the correct connection of hoses, blowpipes,
regulators etc. and correct settings of gas mixtures. This unit should not be selected when Unit 5.21A (Weld using oxyacetylene welding process (OAW) fuel gas welding) has been chosen

This unit could be assessed in conjunction with any other units addressing the safety, quality, communication, materials handling, recording and reporting associated with routine oxyacetylene welding (fuel gas welding) or other units requiring the exercise of the skills and knowledge covered by this unit. Competency in this unit cannot be claimed until all prerequisites have been satisfied