What is spot welding with diagram?

Spot welding (also known as resistance spot welding) is a resistance welding process. This welding process is used primarily for welding two or more metal sheets together by applying pressure and heat from an electric current to the weld area.

What are the parts of a spot weld?

The basic spot welder consists of a power supply, an energy storage unit (e.g., a capacitor bank), a switch, a welding transformer, and the welding electrodes. The energy storage element allows the welder to deliver high instantaneous power levels.

Which metal electrode is used in spot welding?

Copper can be spot welded. But not surprisingly, the standard spot welding copper electrodes do not work. Molybdenum and tungsten electrodes are the primary choices for spot welding copper. These metals have high electrical resistance and melting temperatures.

How thick can you spot weld?

Spot welding is primarily used for joining parts that are normally up to 3 mm in thickness. Thickness of the parts to be welded should be equal or the ratio of thickness should be less than 3:1. The strength of the joint depends on the number and size of the welds. Spot-weld diameters range from 3 mm to 12.5 mm.

Why is copper electrode used in spot welding?

The reason copper is used for the electrodes is that it can maintain a high thermal conductivity and has a low electrical resistance compared to most other metals. This guarantees that the heat is created in the work pieces rather than the electrodes.

What is a welding transformer?

Welding Transformers are used in AC machines to change alternating current from the power line into a low-voltage, high amperage current in the secondary winding.

What are the different types of transformer?

Types of Transformers

  • Power Transformers. A power transformer transfers electricity between a generator and the distribution primary circuits.
  • Autotransformers. Now, let’s make things even more complicated.
  • Generator Step-Up Transformers. Moving right along to GSUs or generator step-up transformers.
  • Auxiliary Transformers.

What is purpose of transformer in spot welding?

The welding transformer steps down the voltage and steps up the current. An important feature of the transformer is it reduces the current level that the switch must handle. The welding electrodes are part of the transformer’s secondary circuit.

How many types of welding transformers are there?

four basic
The four basic types of welding transformers are: 4. The saturable reactor type.

What are types of transformer PDF?

Types of Transformers

  • Step down transformer.
  • Step up transformer.
  • Single phase transformer.
  • Three phase transformer.
  • Power transformer.
  • Distribution transformer.
  • Current transformer.
  • Isolation transformer.

What is the power factor of welding transformer?

Typical Power Factors

plant and appliances cos φ tan φ
resistance type soldering machines 0.8 to 0.9 0.75 to 0.48
arc-welding fixed 1-phase 0.5 1.73
arc-welding motor-generator set 0.7 to 0.9 1.02 to 0.48
arc-welding transformer-rectifier set 0.7 to 0.8 1.02 to 0.75

Are transformer welders AC or DC?

In conventional “transformer” welders, however, the components are much bigger and therefore tend to store heat and take longer to cool. DC Output: Many conventional “transformer” MMA (stick) welders only have AC output, which means they are limited in the types of electrodes they can weld with.

This type of welding transformer consists of a normal reactance, single phase, step down transformer and a separate reactor or choke. The inductive reactance’s and resistances of the windings in such a welding transformer are low, so that its secondary voltage varies but a little with the welding current.

How to calculate spot welding parameters?

Spot Welding Parameters Basic Calculation = 0.241� w ……………………. (1) where E : Energy (J) *Calculation for AC spot welding P : Power (W) tw : Weld time (sec) = 0.241�2� w ……………………. (2) where I : Welding Current (A) R : Panel Contact Resistance (Ω) = JvSL …………………….

What is spot welding?

Spot welds are formed when a large amount of current is passed through the panels for the correct amount of time and with the correct amount of pressure. In a typical spot welding application there are two electrodes, opposite each other, which squeeze the metal pieces together.

What is the destructive inspection technique for spot welding?

The other two inspections are called destructive inspection techniques for evaluating spot welds; they are the “peel” test or “chisel” test. It is obvious that the destructive testing should be done on scrap steel before the process of welding on the vehicle is begun.