Shielded metal arc welding (SMAW) is a manual arc welding process that uses a consumable electrode covered with a flux to lay the weld.
An electric current, in the form of either alternating current or direct current from a welding power supply, is used to form an electric arc between the electrode and the metals to be joined. The workpiece and the electrode melts forming a pool of molten metal (weld pool) that cools to form a joint. As the weld is laid, the flux coating of the electrode disintegrates, giving off vapors that serve as a shielding gas and providing a layer of slag, both of which protect the weld area from atmospheric contamination.
Because of the versatility of the process and the simplicity of its equipment and operation, 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, and though flux-cored arc welding is growing in popularity, 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 (including stainless steel) but aluminium, nickel and copper alloys can also be welded with this method.
Stages of development
Auguste de Méritens
Developed a carbon arc torch that was patented
Nikolay Benardos and Stanisław Olszewski
Developed carbon arc welding
Invented the consumable metal electrode in 1888
C. L. Coffin
Received U.S. Patent 428,459 for his arc welding method that utilized a metal electrode in 1890
Karl Kristian Masden
Described an automated variation of SMAW in 1945
- in the process of exposure to a large number of harmful substances, both for the welder and for others;
- the quality of the weld depends largely on the experience and qualifications of the welder;
- the speed of work is often lower than with other methods;
- when welding with direct current, the magnetic fields are very different from the arc, which is necessary for the process.
- ease of operation and low price of equipment for the welding process;
- the possibility of welding a large number of metal grades, taking into account the range of choice of electrode material;
- the ability to perform welding work in hard-to-reach places;
- welding in any spatial positions is appropriate.