Shielded metal arc welding
Shielded metal arc welding is one of the world’s first and most popular welding processes. SMAW continues to be used extensively in the construction of heavy steel structures and in industrial fabrication. The process is used primarily to weld iron and steels but aluminium, nickel and copper alloys can also be welded with this method.
About Shielded metal arc welding in brief
Shielded metal arc welding is one of the world’s first and most popular welding processes. It dominates other welding processes in the maintenance and repair industry. SMAW continues to be used extensively in the construction of heavy steel structures and in industrial fabrication. The process is used primarily to weld iron and steels but aluminium, nickel and copper alloys can also be welded with this method. In the 1950s, manufacturers introduced iron powder into the flux coating, making it possible to increase the welding speed. Another little used variation of the process, known as firecracker welding, was developed around the same time by George Hafergut in Austria. In 1964 laser welding was developed in Bell Laboratory with the intention of using this technology as a powerful heat source for cutting and tooling. To strike an arc, which varies widely based upon electrode and workpiece composition, can be the hardest skill for beginners. The orientation of the electrode to workpiece is where most stumble, if the electrode is held at a perpendicular angle to the workpiece the tip will likely stick to the metal which will cause it to heat up very rapidly. The electrode needs to be at a lower angle, which allows the weld pool to flow rapidly out of the tip. As the electrode melts giving off shielding gases that protect the weld area from oxygen and other gases, the slag provides a layer of slag which covers the filler as it travels from the welding pool to the electrode. This combined activity, combined with chipping away with the electrode holder, chipped away to reveal the weld.
Once hardened, the weld surface floats to the surface and protects the weld from contamination as it solidifies. As welding progresses, the electrode must periodically stop welding to remove the remaining stub and insert a new electrode into the holder and insert it into the new weld. In 1945 Karl Kristian Masden described an automated variation of S MAW, now known as gravity welding. It briefly gained popularity in the 1960s after receiving publicity for its use in Japanese shipyards though today its applications are limited. In 1885, Nikolay Benardos and Stanisław Olszewski developed carbon arc welding, obtaining American patents from 1887 showing a rudimentary electrode holder. In 1888, the consumable metal electrode was invented by Nikolay Slavyanov. In 1890, C. L. Coffin received U. S. Patent 428,459 for his arc welding method that utilized a metal electrode. In 1912, Arthur Percy Strohmenger released a heavily coated electrode, but high cost and complex production methods prevented these early electrodes from gaining popularity. In 1927, the development of an extrusion process reduced the cost of coating electrodes while allowing manufacturers to produce more complex coating mixtures designed for specific applications. This process, like SMAw, deposited melted electrode metal into the weld as filler. It is still used today in many industries including aerospace, defense, construction, and manufacturing, but it is not widely used in the military.