The basic idea of joining one metal to another using a third material to fuse the two is easy to understand. This is an introduction to the various welding techniques and technologies used by a machine shop for industrial fabrication. Pipes, scaffolding, safety cages, and other metalwork call for different processes.
The right process and technology to use also depend on the nature of the metals, whether the work is indoors or outdoors, and the shape of the material to be joined. Welders will use those variables to help them choose a process and decide on certain other specifics. While welding might just seem like a process of using heat to connect two pieces of metal, there is far more to it. Different techniques and equipment exist for different purposes, and different industrial fabrication jobs call for a diverse skillset.
Industrial Welding Basics
All forms of welding use electricity, an electrode, a torch, and flux. Electrodes come in a few different types – a coated electrode has the flux applied to the outside where it vaporizes under intense heating. Flux is a cleaner composed of organic and inorganic compounds. Flux comes in a wide variety of “flavors” for different welding applications. Some contain metal alloys, but they also include compounds like borax, zinc chloride, and ammonium chloride. Flux materials can be toxic or carcinogenic, so many industrial welding jobs call for excellent ventilation or masks if the work must be done indoors.
Some welding technologies work better for different fabrication jobs. A variety of variables determines what technology is best and how to use it for a specific fabrication job. The most important factors are probably as follows:
- Shape and thickness of metal to weld
- Composition of the metal to be welded
- Indoor versus outdoor
In no particular order, here are the four basic processes a machine shop could use to fabricate or repair metal items for a commercial or industrial setting.
Gas Metal Arc Welding (GMAW)
Also known as MIG or metal inert gas, this is what most people think of when they think of welding. It is probably the most common technique in industrial fabrication and repair work due to being both widely useful and easier to master than some other welding technologies. In GMAW and stick welding, the electrode material melts onto the base metal. It is most useful on thin sheets and tubes. This type of welding also uses an inert shielding gas, such as argon or helium to prevent the working area from becoming contaminated. As with other processes, nitrogen and oxygen need to be kept away from the working area. This need to protect the working area from atmospheric contamination shows how other processes work.
Shielded Metal Arc Welding (SMAW)
This process is also a type of “stick welding.” Welders would mainly use this technique on thick metal, rusted parts, or parts that cannot be properly cleaned before welding. Because of being so widely applicable to various repair and fabrication jobs it is probably the most popular welding technique perhaps accounting for more than 50% of welding jobs worldwide.
Gas Tungsten Arc Welding
Also known as TIG or Tungsten Inert Gas welding, this one is hard to master but valuable for certain industrial jobs. You need to use an inert gas to shield the working area from contamination and you need to have a clean surface. TIG welding can be a bit inconvenient to use because of the need for an external shielding gas but it offers long-term corrosion resistance and cracking. This process is great for welding thin-walled, small-diameter tubes like you find in bicycle frames.
Flux Cored Arc Welding
Faster than either MIG or SMAW but probably more expensive, this welding method uses a tube of flux material surrounded by filler material in creating welds. This process is good for a wide range of steels and some nickel alloys, and it may be somewhat easier to use.
Submerged Arc Welding
This is an automated process used when the customer needs a high-precision weld. It works nicely when you need a precise straight or circular weld, on a pipe for example. Granular flux covers the working area to keep it clean, so the electrode is submerged in flux material. As an automated process, high precision is easy to achieve with the right programming. While this methodology can be fast and useful for both outdoor and indoor jobs, it is limited in applicability to a degree. It only works with steel and some nickel-based alloys.
Many Techniques for Diverse Fabrication Challenges
The best industrial welding and fabrication machine shops use a variety of welding tools to match the range of welding jobs that clients need. From building a large metal cage to patching up some old safety railing, Hamilton Machine employs certified welders who can handle an impressive variety of welding operations in one of our middle Tennessee facilities or at your job site with our mobile welding gear. Contact us to learn more about our services.
