Explain briefly the different welding processes under resistance welding. Why is it necessary to use welding transformer?

Resistance welding is a group of welding processes that involve applying pressure and electrical current to two or more metal parts to fuse them together. There are several different types of resistance welding processes, including:

1.     Spot welding: In this process, two or more metal parts are clamped together between two electrodes, and an electrical current is passed through the metal at the point of contact. The resistance of the metal causes it to heat up and melt, forming a weld. Spot welding is commonly used in the automotive industry for joining sheet metal parts.

2.     Seam welding: Seam welding is similar to spot welding, but the electrodes are moved along the joint, creating a continuous seam weld. This process is commonly used for welding pipes, tubes, and other cylindrical structures.

3.     Projection welding: In projection welding, the metal parts to be joined have raised sections or projections that concentrate the current and heat, forming a weld. This process is often used for welding nuts, bolts, and other fasteners to sheet metal parts.

4.     Resistance butt welding: Resistance butt welding is used to join two metal parts of the same or different shapes by bringing their ends together and applying pressure and current. This process is often used for welding wires, rods, and tubes.

Each resistance welding process has its own advantages and limitations, and the selection of the appropriate process depends on factors such as the type and thickness of the materials being welded, the required weld quality, and the production volume.

Welding transformers are commonly used in resistance welding processes because they provide several benefits, including:

1.     Voltage regulation: Welding transformers can regulate the voltage supplied to the welding electrodes, ensuring a consistent and controlled welding process. This is important for achieving high-quality welds and reducing the risk of defects.

2.     Current control: Welding transformers can also control the current supplied to the welding electrodes, which is necessary for achieving the proper level of heat and weld penetration. This is important for ensuring that the welds meet the required strength and durability standards.

3.     Efficient power delivery: Welding transformers can deliver high levels of electrical power to the welding electrodes with minimal energy loss, which is important for maintaining high welding speeds and reducing energy costs.

4.     Safety: Welding transformers are designed to operate safely and reliably in harsh welding environments, protecting operators and equipment from electrical hazards and damage.

In summary, welding transformers are necessary in resistance welding processes to regulate the voltage and current supplied to the welding electrodes, provide efficient power delivery, and ensure safe and reliable operation.