What is Arc Welding - Applications and Process Types

Arc welding is a joining technique that uses an electric arc to generate heat and melt metals. Direct (DC) or alternating (AC) currents from a power source generate an electric arc between a consumable or non-consumable electrode and the base material.

What is the Arc Welding Process?

Metals are fused using the arc welding method. The metal at the joint between two workpieces melts when an electric arc from an AC or DC power source generates intense heat of about 6500°F.

The electrode either conducts the current or conducts and melts filler metal into the weld pool at the same time to reinforce it. You can mechanically or manually steer the arc along the join line to get the perfect weld with arc welding machine.

A protective shielding gas or slag is employed to minimize the contact of the molten metal with the air. This is because the metals react chemically to oxygen and nitrogen in the air when heated to high temperatures by the arc. The molten metals solidify to create a metallurgical link once they have cooled. Consider the important arc welding safety tips before start working on metals.

What Are The Different Types Of Arc Welding Process?

Consumable and non-consumable electrode approaches are two different forms of this process.

Methods With Consumable Electrodes

The base metals are shielded from contamination using a shielding gas during the processes of metal inert gas welding (MIG) and metal active gas welding (MAG), also known as gas metal arc welding (GMAW).

1. Metal Arc Shield Welding (SMAW)

This type of welding process, where an arc is struck between a metal electrode (which has been flux coated) and the workpiece, causing both the electrodes and workpiece surface to melt and form a weld pool, is called flux-shielded arc welding, manual metal arc welding, or stick welding. The electrode's flux layer will simultaneously melt and produce gas and slag, shielding the weld pool from the atmosphere. This method is adaptable and suitable for combining ferrous and non-ferrous components in all situations and with various material thicknesses.

2. Arc Flux-Cored Welding (FCAW)

A continuously fed consumable flux cored electrode and a constant voltage power source are employed in FCAW, a SMAW substitute that maintains a constant arc length. This procedure uses a shielding gas or the gas produced by the flux to prevent contamination.

3. Submerged Arc Welding (SAW)

A common welding technique is submerged arc welding (SAW), which uses a consumable electrode that is continuously fed as well as a fusible flux blanket that, when molten, becomes conductive and creates a path for current to flow between the electrode and the component. Additionally, the flux reduces UV radiation and pollutants while preventing sparks and splatter.

ESW is a vertical procedure that welds thick plates (those over 25 mm) in a single pass. ESW needs an electric arc to ignite before a flux addition puts it out. As the wire consumable is fed into the melting pool, the flux melts, resulting in a layer of molten slag on top of the pool. The resistance of the molten slag to the flow of electric current is what heats the wire and plate edges. The technique is followed by two copper shoes that have been water-cooled to stop any molten slag from running off.

Read More: Difference Between Metal Fabrication and Welding

4. "Arc Stud Welding" (SW)

Like flash welding, SW attaches a nut or fastener to another metal item by melting a flange with nubs.

Methods With Non-Consumable Electrodes

The non-consumable tungsten electrodes is used to create the arc in tungsten inert gas welding (TIG), also known as gas tungsten arc welding (GTAW). An inert shielding gas protects the weld and molten pool from air contamination.

Plasma Arc Welding (PAW)

Similar to TIG, Plasma Arc Welding (PAW) creates an electric arc between an anode and a non-consumable electrode inside the torch's body. The electric arc ionizes the gas in the torch to produce plasma. This plasma is then forced through a small borehole in the anode and onto the base plate. Thus, plasma and a shielding gas are divided.

Where Is Plasma Arc Welding Used?

All industrial sectors utilize this standard joining procedure, including automotive, aerospace, oil and gas, power, and construction.

Types Of Electrodes Used In The Arc Welding Process

Numerous electrodes with various strengths, weaknesses, and applications are used in the arc process, which might affect the weld quality. The rod is connected to the welding machine to attach the work parts, and current is transmitted through it.

These consumable electrodes melt in some circumstances, like with SMAW, and form a weld component. Other times, like when using TIG, the electrode electrodes don't melt since they are non-consumable.

In general, electrodes are coated, albeit the specific type of coating varies. Although there are uncoated electrodes, they are much less common, produce more spatter, and can be challenging to regulate the arc. To reduce or eliminate polluting oxides or sulfur, coated electrodes are preferable. There are three different types of welding electrode coatings: cellulose, minerals, or a mix of the two. Whether coated or uncoated, the proper electrodes must be used to produce clean, strong welds and have the proper bead quality.

Benefits Of Arc Welding Process

• When compared to other welding techniques, there are many benefits. This economic strategy also uses less equipment because no gas is involved, and the equipment cost is quite low.
• It is a portable joining technique that works with unclean metals as well. While shielding gas is frequently used in arc operations, it is not always required. As a result, work can be done in any weather, and spatter is not a problem.

Drawbacks Of Arc Welding Process

Although this technique has a lot of benefits, there are also some downsides. Because this form of welding generates more waste than other welding techniques, project costs may be increased in some cases. While joining thin materials using arc processes can be challenging, this process also necessitates a high level of expertise and training for arc welders.