back to basics

GTAW, GMAW , Sub-Arc and Stick Welding – What’s the difference?  Part 1

Have you all been wondering what I have learned recently? Well, I have decided to start with Welding Types. I will start with the prettiest, since that is my forte. TIG welding, also known as GTAW, also known as Heliarc Welding. What are all the abbreviations you ask? TIG stands for Tungsten Inert Gas. The American Welding Society calls this process GTAW – Gas Tungsten Arc Welding. Why all the different abbreviations or a.k.a.’s for the same procedure? Well, your guess is as good as mine on that one. If anyone out there has the answer to that, I’m all ears and would love to know.

GTAW welding, is an arc welding process that uses a non-consumable tungsten electrode to produce the weld. This is the most aesthetically pleasing weld to look at, but can also be the most challenging to create.  With this style, you need to create a steady current – typically with a foot petal – maintain an even gap between the electrode and the metal, and, if needed, use a filler metal all at the same time.  Let’s just say those who cannot chew gum and walk at the same time, should probably not try this method of welding.  It is a bit more time consuming, but requires little grinding, and creates a look of “stacked dimes”.

I have enlisted the help of Shawn Hoglund, C4 Welding’s Weld Engineer, to break down some of what happens here at C4. “We use GTAW for various types of welding. We use it daily in the Pipe kit areas for putting the root and hot passes in the pipe to pipe or pipe to flange welds. We use it in the Tank line to fix any deficiencies that may occur, such as: under cut, porosity, rollover or blending of starts and stops.  Depending on the different types of material being used (aluminum, stainless or other nonferrous materials) or material thickness (typically thin materials) we are welding on, GTAW, is preferred because the welder will have more control over the welding process.”

Moving on, MIG (Metal Inert Gas) welding, a.k.a GMAW (Gas Metal Arc Welding), a.k.a Wire Welding is a welding process in which an electric arc forms between a consumable MIG wire electrode and the workpiece, which heats the metal, causing them to melt and join. Along with the wire electrode, a shielding gas feeds through the welding gun, which shields the process from contaminants in the air.  While the welds in this method are not the prettiest, they are the easiest to create; this method is the least time consuming, as the welder can deposit more weld metal in a shorter period of time; but does usually require some grinding when completed.  MIG welding is the best for beginners and is typically the method used on every farm in America. I am hoping I can convince someone here to teach me this one so I can say I “know how to weld”.

According to Shawn, “GMAW is used for the bulk of our workload and is most common for day to day use. The main reason for this is the weld deposition rate is much higher; boosting production and efficiency. GMAW is used in all areas of the shop. From filling out the groove welds/cover passes in the Pipe kit area, to welding all the nozzles and couplings in our tanks, and building tables in the machine shop fabrication area.”

It has been an exciting week for me to learn so many new things.  I’m starting to understand what is happening on the shop floor which has drastically reduced the amount of dumb questions coming out of my mouth. Check back in a couple weeks when I will have Part 2 of this complete; Sub-Arc and Stick Welding. And, hopefully, I can share a story or two on my first welding experience!