All About Resistance Welding Process :Definition, Working Principle, Types, Advantages, Dis-advantages, Application

Introduction:

What is Resistance Welding?

Resistance welding is that the process during which the use of the electric resistance for generating heat required for melting the workpiece.

It is typically used for connecting thin plates and structures. It has various types like Seam welding, Projection welding, and Spot welding.

 

Working Principle:

The material which is to be joined is clamped between 2 electrodes and a high current is applied.

Resistance heating at the contact surfaces causes native melting and fusion.

High currents (typically 10000 A) are applied for brief durations and pressure is applied to the electrodes before the appliance of current and for a brief time after the present has ceased to flow. 

Features of the fundamental resistance welding process include:

The process requires relatively simple equipment;

It is easily and normally automated;

Once the welding parameters are established it should be possible to supply repeatable welds for relatively long production runs.

Advantages of Resistance Welding:

• They are very rapid in operation.

• The equipment can be fully automated.

• They conserve materials as no filler material, shielding gas or flux is needed.

• Skilled operators are not required.

• Dissimilar metals can be easily joined.

• A high degree of reliability and reproducibility are often achieved.

 

Limitations of Resistance Welding:

• The equipment has a high initial cost.

• There are limitations to the sort of joints which will be made (mostly suitable for lap joints).

• Skilled maintenance persons are needed to service the control equipment.

• Some materials require special surface preparations before welding.

 

Applications of Resistance Welding:

• The major applications of the method are within the joining of sheet steel within the automotive and white-goods manufacturing industries.

Types of Resistance Welding:

Different types of resistance welding process are:

Resistance Spot Welding :

Spot welding bonds alongside two or extra metal sheets, which are related in an overlapping position between a pair of welding electrodes, one fixed and one versatile.

When heavy series current is directed through these electrodes, the highest electrode also simultaneously adds downward pressure. The result's a weld that takes place at the spot between the 2 electrodes. To frame further welds, the sheets are moved and repositioned.

Advantages of Spot Welding:

• Spot welding typically comes at a lower value, each in equipment and labor.

• Spot welding does not typically need the advanced level of skills training needed by more precise or complex welding work.

• Additionally, spot welding is usually faster than other sorts of welding operations.

Disadvantages of Spot Welding:

• More skilled labor might be required for the continued maintenance of spot-welded pieces.

• Additionally, spot welding will not work if the items to be welded are of any vital thickness.

Applications of Spot Welding:

• Spot welding is sometimes utilized among the manufacture of automobiles, aircraft, Steel household furniture, and steel containers.

Resistance Projection Welding :

Projection welding joins metal sheets or elements parts using electrodes.

These electrodes are applied to the metal piece items to be joined together. Then, opposing forces are applied through the electrodes.

 

Advantages of Projection Welding:

• As the welder can weld quite one spot at a time. Additionally, the welder can position welded spots more closely to every aside from is feasible with spot welding finally; welds will look somewhat neater and fewer obtrusive than with spot welding.

 

Disadvantages of Projection Welding:

• Projection welding can't be used on metals.

• Projection welding can finish up costing more, thanks to the upper investment within the required equipment.

 

Applications of Projection Welding:

• Used primarily within the electrical, automotive, and construction fields.

 

Resistance Butt Welding :

In butt welding, the adjoining of two surfaces happens at the same time over the entire of the affected workpiece surfaces instead of in small spots.

The heat that's required to produce that connection is created by the electrical resistance that's produced by resistance to the current that's being passed through and between those two surfaces as they face each other.

In a basic butt weld, the 2 pieces to be welded are first brought together struggling. Current is then applied, heating the contact space area enough to permit the applied pressure to forge the parts together.

The welder continues to use both pressure and current. Until the affected area becomes pliable and softened the continual, even application of pressure eventually creates the welded joint, which is usually quite smooth and even.

Butt welding is most frequently utilized in wires and rods with small diameter measurements.

 

Resistance Seam Welding :

Seam welding uses wheel-shaped electrodes to supply longer, continual welds for a stronger joint.

While some joints have to be welded by a proficient individual welder, seam welding lends itself well to an automatic machine process.

The result's fast and accurate welding with incredibly strong joints.

Seam welding can also turn out multiple parallel seams with less overlap compared to spot or projection welding methods.

Additionally, seam welding produces joints that will not allow the escape of gas or liquid contents.

 

Disadvantages of Seam Welding:

• It generally costs more to realize a seam-welded joint than it might through other methods.

• Seam welding is merely appropriate for straight axis seams.

• It are often difficult to make a joint for any pieces thicker than 3 millimeters.