Viva/ Interview Questions and Answers on ARC Welding

What is ARC welding?

ARC welding is a welding process that uses a welding power supply to create an electric arc between a metal electrode and the workpiece. The heat generated by the arc melts the metal and the electrode forms a pool of molten metal that solidifies to form a strong joint.

Viva/ Interview Questions and Answers on ARC Welding

What is the principle behind ARC welding?

The principle behind ARC welding is that heat is generated by an electric arc between the electrode and the workpiece. The heat generated by the arc melts the metal, and the electrode forms a pool of molten metal that solidifies to form a strong joint.

What are the different types of ARC welding?

There are several types of ARC welding including Shielded Metal ARC Welding (SMAW), Gas Tungsten ARC Welding (GTAW), Gas Metal ARC Welding (GMAW), Flux-Cored ARC Welding (FCAW), and Submerged ARC Welding (SAW).

What are the advantages of ARC welding?

ARC welding has several advantages including high deposition rates, the ability to weld in all positions, and the ability to join a wide range of metals including steel, aluminum, and stainless steel.

What is the difference between SMAW and GTAW welding?

SMAW (Shielded Metal ARC Welding) uses a consumable electrode that is coated in flux to protect the weld from atmospheric contamination. GTAW (Gas Tungsten ARC Welding) uses a non-consumable tungsten electrode and a separate filler metal, with shielding gas to protect the weld from atmospheric contamination. SMAW is easier to learn but requires more cleanup, while GTAW is more precise but requires more skill and experience to perform.

What is the difference between GMAW and FCAW welding?

GMAW (Gas Metal ARC Welding) uses a continuous wire feed that acts as both the electrode and filler metal, and a shielding gas to protect the weld. FCAW (Flux-Cored ARC Welding) also uses a continuous wire feed, but the electrode is hollow and contains flux powder that provides shielding and contributes to the weld. GMAW is faster and more efficient, while FCAW is better suited for outdoor and windy conditions.

What is the difference between SAW and GMAW welding?

SAW (Submerged ARC Welding) uses a flux-covered electrode that is fed continuously into the weld pool, which is protected by a blanket of flux that covers the molten metal. GMAW (Gas Metal ARC Welding) uses a continuous wire feed that acts as both the electrode and filler metal, and a shielding gas to protect the weld. SAW is typically used for welding large plates and is not as versatile as GMAW.

What are the common applications of ARC welding?

ARC welding is commonly used in various industries including construction, manufacturing, shipbuilding, and repair and maintenance. It is used to join a wide range of metals including steel, aluminum, and stainless steel.

What are the safety precautions to be taken while performing ARC welding?

Some of the safety precautions to be taken while performing ARC welding include wearing appropriate personal protective equipment such as a welding helmet, gloves, and protective clothing, ensuring proper ventilation to prevent exposure to welding fumes, and ensuring that the work area is free from flammable materials.

What is the process of setting up an ARC welding machine?

The process of setting up an ARC welding machine typically involves selecting the correct electrode, setting the correct welding current, selecting the correct shielding gas, and making sure the workpiece is properly positioned and clamped.

How does the choice of electrode affect the quality of the weld?

The choice of electrode affects the quality of the weld because different electrodes have different properties such as melting point, tensile strength, and ductility. Selecting the correct electrode for the application is critical to producing a strong, high-quality weld.

What is the purpose of the shielding gas in ARC welding?

The purpose of the shielding gas in ARC welding is to protect the weld from atmospheric contamination, which can cause porosity, cracking, and other defects in the weld. The shielding gas also affects the transfer of metal from the electrode to the workpiece, and can influence the penetration, bead shape, and overall quality of the weld.

What are the factors that influence the penetration of an ARC weld?

The factors that influence the penetration of an ARC weld include the welding current, electrode size, electrode composition, shielding gas, and welding speed. Increasing the welding current or using a larger electrode can increase penetration, while reducing the welding speed or using a smaller electrode can reduce penetration.

What is the role of filler metal in ARC welding?

The role of filler metal in ARC welding is to add material to the joint to build up the required thickness and to reinforce the joint. Filler metal is added to the joint by either using a consumable electrode in SMAW welding or a continuous wire feed in GMAW or FCAW welding.

What is the importance of proper joint preparation in ARC welding?

Proper joint preparation is important in ARC welding because it affects the strength and quality of the weld. Proper joint preparation involves cleaning the surfaces to be welded, aligning the pieces, and ensuring that there is adequate gap between the pieces to allow for complete penetration and adequate filler metal.

How does welding speed affect the quality of an ARC weld?

Welding speed affects the quality of an ARC weld because it affects the penetration, bead shape, and overall appearance of the weld. Too slow of a welding speed can result in shallow penetration and a wider bead, while too fast of a welding speed can result in excessive penetration and a narrower bead.

What is the difference between DC and AC welding current?

DC (Direct Current) welding current flows in one direction, while AC (Alternating Current) welding current changes direction. DC welding current is typically used for welding steels and stainless steels, while AC welding current is used for aluminum and magnesium.

How does the choice of shielding gas affect the quality of an ARC weld?

The choice of shielding gas affects the quality of an ARC weld by influencing the transfer of metal from the electrode to the workpiece, and by affecting the penetration, bead shape, and overall quality of the weld. Different shielding gases have different properties and react differently with the metal being welded, so selecting the correct shielding gas is critical to producing a high-quality weld.

What is the difference between a coated electrode and a bare electrode in ARC welding?

A coated electrode in ARC welding is covered in a flux that protects the weld from atmospheric contamination and provides a shielding gas. A bare electrode does not have a flux coating and is typically used for welding in a controlled environment where atmospheric contamination is not a concern.