Fabrication Information

Don’t Judge a Weld By Its Photo – Different Welding Processes Explained

Posted on December 5, 2016

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Superior manufacturing is only as strong as its weakest building process; for this reason, it is paramount that industrial, commercial and petrochemical manufacturers be able to demonstrate and excel at the latest and most appropriate custom fabrication processes.

For manufacturing fabrication organizations, having a complete and intimate knowledge of different materials, metals, and their relationships to one another is one of, if not the most important aspect of a build.

In today’s various manufacturing industries, good welders are increasingly difficult to find. It’s estimated that 80% of companies have trouble finding qualified welders, and the global construction industry’s need for welders will increase by 26% in the next decade.

Today, we’re often seduced by beautiful photographs of seemingly perfect welds, renowned for their uniformity, shine, symmetry and perceived strength, giving these welds an aesthetic worth. While cosmetically stunning, these welds can sometimes be the wrong technique for the application it’s being used on. For this purpose, we’ll outline the different types of welding, their industrial capacities, appropriate uses within the manufacturing sector, and differences in chemical processes.

 

Stick Welding / SMAW

Otherwise known as SMAW or shielded metal arc welding, stick welding is one of the oldest welding processes still used in mainstream construction and maintenance projects today.

Invented in the 1920’s as an inexpensive, mobile welding service that could offer versatility and easily operable in both indoor and outdoor environments. Stick welding is one of the most popular and most-used welding processes in the construction of steel structures and industrial fabrication and has only recently seen a decline as ARC welding has become popular in industrial circles.

It’s commonly used to weld steel and stainless steel, as well as other metals such as carbon steel, low and high alloy steel, cast iron and ductile iron. Common issues with stick welding are the quality of welds, most notably in regards to weld splatter, porosity, poor fusion, cracking and shallow weld penetration. In those beautiful photos of near perfect welds – you’re likely not seeing a stick weld. Weld splatter, usually caused by an excessively high current, isn’t detrimental to the function and quality of the weld but damages its visual appearance and increases cleaning costs.

 

MIG Welding

Standing for Metal Inert Gas welding, the MIG welding process uses electricity to melt and infuse metal pieces together. Commonly referred to as the ‘easiest’ welding technique to use and master, the MIG process was first invented in the 1940’s. It’s a very fast and efficient process, and therefore a favorite of many indoor and fast-paced maintenance or fabrication organizations. It can’t be used outdoors in a mobile capacity very well, as the equipment is difficult to transport.

MIG can be used to weld various types of metal, including carbon and stainless steels, aluminum, magnesium, copper, nickel, silicon bronze and other alloys. It’s also a proficient method for joining metal in a wide range of thicknesses.

The basic process involves an arc of electricity that creates a short circuit between a continuous anode (the wire feeding the welding gun) and a cathode (the metal itself that is being welding). The heat produced by the short circuit and a nonreactive, or inert gas, melts the metal allowing them to fuse together.

It provides a good quality weld and a visually pleasing weld bead, making it a popular choice for visible welding processes. It features minimal weld splatter and is suitable for all-position welding. It falls short in that it produces dross (a mass of solid impurities floating in molten metal), and for porosity which can lead to weakened, less ductile welds.

 

Flux Cored Arc Welding / FCAW

Similar to the MIG process as far as equipment and technique are concerned, flux-cored ARC welding was developed in the 1950’s as an alternative to stick welding by eliminating the stick electrode used in SMAW, helping the process to overcome restrictions often associated with stick welding. Flux-cored ARC welding can use one of two processes:

One uses a shielding gas from an external supply to keep the weld surface free of potential atmospheric contamination, developed and used primarily for welding structural steels – making it a good choice for manufacturing fabrication where welding thicker metals are required. The second uses no shielding gas made possible by the flux core in the electrode used to develop current. This second type is a popular choice of welding technique as its more mobile and portable than its shielding gas alternative, and offers good penetration to the base metal, increasing strength. Further, the lack of a shielding gas means this is a decent outdoor welding technique, not being affected by the wind.

It’s a more costly process due to its equipment – namely a more costly filler material/wire – and generates a fair bit of smoke compared to other processes. Advantages include the excess welding slag is easy to remove, there is less pre-cleaning of metal required, and offers high-speed applications.

 

TIG Welding

Tungsten Inert Gas welding uses a nonconsumable tungsten electrode to produce a weld. Shielding gas – usually helium or argon – helps the weld area to be protected from atmospheric contamination like nitrogen and oxygen which can cause fusion defects, porosity, and brittle welds. The gas also helps to maintain a stable arc by transferring heat from the tungsten electrode to the metal.

The process is one of the more difficult welding techniques, because of the level of coordination required of the operator. TIG produces a strong, high-quality weld that is complex and difficult to master. The process is considerably slower than other welding techniques, giving the welder applicable time to produce a highly pleasing and visually beautiful weld bead.

Commonly used to weld thin pieces, and nonferrous metals like aluminum and magnesium, TIG welding is used in the aerospace industry extensively to manufacture space vehicles and in more mainstream industries like bicycle construction in which thin-walled tubing needs to be welded. No other welding process allows the operator to weld so many different metal alloys in so many configurations making it an adaptable process.

 

In modern day manufacturing, it is so important to be sure that the welding techniques you choose to employ for your specific build coincide with the fabrication requirements of the materials you are working with. Further, it’s critical that your welders be a part of the on-site and off-site modular construction process discussion, ensuring that the best weld techniques and talents are used where they are needed, guaranteeing structural integrity, strength, quality – and yes, even those photo-worthy welds we see all too often.

This proves yet another distinct benefit to employing the expertise of a domestic modular fabrication company; one that bases their reputation on the satisfaction and quality of their work through open and transparent collaboration with their clients and partners. All too often, we see the detrimental setback of working with cheaper, overseas fabrication outfits that choose speed and profit over quality and consistency. With the professionalism and expert fabrication knowledge of Saskarc’s trusted industry professionals, you invest in our ability to deliver the best product possible.