4. Process Research

MIG welding is a semi-automatic arc welding process in which an electric arc is struck betweena  continuously fed electrode wire and the work.

Electric current is transferred to the wire through the contact tip in the welding gun or torch. The electrode is not flux coated. It is, in most MIG welding applications, a bare solid wire which becomes the filler metal as it is continuously fed to the weld area during the welding process.

The wire, weld pool and the general weld area are protected from atmospheric contamination by a shielding gas which is fed through the welding torch. Shielding gases are selected to suit the particular job. Argon and CO2 mixtures are generally used when welding steel.

MIG welding combines the use of electrical energy, continuously fed filler metal and shielding gas into a fast, efficient and economical process that is used throughout industry.

Gas Metal Arc Welding (GMAW) has numerous advantages over other types of welding. Advantages which relate to the use of solid filler wire in the MIG welding process are included in the list which follows:

• faster welding speed

• flux is not used

• there is no slag to be chipped off the finished weld

• very little smoke or fumes are produced

• welding can be performed in all positions

• in some applications the MIG process is capable of welding mild steel without edge preparation if necessary

• most metals can be welded by changing the electrode wire and sometimes the shielding gas

• there is less distortion than with other welding processes

• spot welds can be performed very efficiently

• there is very little wastage of consumables (filler wire)

Generally, the surface you are welding should be thoroughly dry and free from rust, scale, grease, paint or any other foreign matter. The weld area can be cleaned by wire brushing, filing or grinding.

The images below show some basic joints that will be used for the F Clamp project.