Principle of Shielding Metal Arc Welding Process and Differences from GMAW

The Working Principle of Shielded Metal Arc Welding Process

Shielded Metal Arc Welding process uses the heat from an arc to melt a consumable covered electrode and the top of the base metal. Both the electrode and the object being welded are part of the circuit. The circuit also includes a power source, welding cable, welding electrode holder, and ground clamp. The cable from the power source connects to the workpiece and the electrode holder. When an arc is struck between the base metal and the electrode tip, welding begins. The surface of the workpiece and the electrode tip melt. The metal then forms at the end of the electrode and transfers from the arc to the molten pool. When the electrode is consumed, filler metal is deposited. The arc in the Shielded Metal Arc Welding process becomes very hot - temperatures can exceed 9,000 degrees Fahrenheit!

What You Need to Know About Shielded Metal Arc Welding Process

Shielded Metal Arc Welding voltage: Voltage is one of the main variables in arc welding. While some welding processes can use a preset constant voltage system to maintain this, with Shielded Metal Arc Welding, the voltage is manually adjusted. This is done by moving the control lever closer to or further from the workpiece.

Shielded Metal Arc Welding current: Most Shielded Metal GMAW MIG Welding Processes and other manual welding processes use a constant current power source. This provides a consistent preset current and keeps the ampere setting.

Shielded Metal Arc Welding polarity: In the Shielded Metal Arc Welding process, reverse polarity is almost always used. It helps to provide the best weld bead profile and depth of penetration, and it can also reduce excessive spatter, which are drops of molten material produced at or near the arc of the welding.

Shielded Metal Arc Welding process components: Some basic tools used in stick welding include: an arc welding power source (welder), electrode wires, electrode holder, cable, cable connectors, ground clamp, chipping hammer. As with any other welding process, the welder uses safety equipment. This includes a helmet, gloves, and protective clothing.

What Is the Difference Between GMAW and Shielded Metal Arc Welding Process?

Gas Metal Arc Welding or MIG welding GMAW  uses an arc between a metal and a wire electrode. A continuous solid wire electrode is fed through a gun and shielded by a gas to protect the weld from contaminants in the air. On the other hand, Shielded Metal Arc Welding process uses a covered electrode that produces a gas shield when heated, so it doesn't rely on external gas like GMAW. Shielded Metal Arc Welding welders also need to regularly replace the electrode, while GMAW has an automatic wire feeder.