Metal Welding Processes – A Primer

You could spend days on end attempting to visualize all the metal products that are welded during their production and never come close to the total number. Drive your car, fly in a plane, sail away in a boat or just reach into your refrigerator for a cold drink. Some part of each of those items has reached it’s final shape through some process of metal welding. It is not too far fetched to state that if for some reason all the metal welds in the world failed at once there would be nothing left but a hugh scrap pile.Learn more at –welding.

To achieve this vast amount of finished welds a number of different welding processes have been developed. While differing greatly in their application the basic process remains the same. Heat two pieces of metal sufficiently to reach a point where they will fuse together. Sometimes a filler metal is used and other times simply heating and applying enough pressure will achieve the desired results as is done with spot welding.

Some of these welding processes are very exotic and beyond the scope of this discussion. Here we are interested in describing the welding processes that would be found in any welding shop or manufacturing plant. Probably the most basic and well known welding technique is gas welding. In this process oxygen is carefully mixed with other gasses such as acetylene, propane, natural gas and others depending on the type material to be welded and the amount of heat needed. Gas cost is also a determining factor in this process as some of these gasses are expensive and not needed for many welding chores.

These gasses are mixed and then flowed through a torch which is then lit and adjusted to promote the necessary heat needed. A filler rod is then applied and melted at the same time to complete the weld. In general the filler rod would be a bare rod but in some cases various coated rods may be needed.

The next weld process is well known as arc welding or electric arc welding and has been around for over a hundred years. Basically an electric arc is produced by transmitting a controlled electrical current through a welding rod. These welding rods are most often coated with various materials which act as a shield to the molten weld puddle. If the puddle were left unshielded it would become contaminated with gases from the air and produce a weak or otherwise unsatisfactory weld.

The basic electric arc welding process has progressed rapidly through the years to accommodate more exotic metals. Two of these processes are TIG,(tungsten inert gas), and Mig welding. These two processes differ in that in Mig welding a coil of welding wire is used as a filler material and is consumed during the welding cycle. In the TIG process a tungsten tip is used to produce the arc which heats the metal but a separate filler is used and the tungsten tip is not consumed during welding.