Introduction to Welding & Classification of Welding


Table of Contents

What is Welding?

Welding is the process of joining together two pieces of metal so that bonding takes place at their original boundary surfaces”. When two parts to be joined are melted together, heat or pressure or both is applied and with or without added metal for formation of metallic bond There are many types of welding techniques used to join metals. The welding processes differ in the manner in which temperature and pressure are combined and achieved.

What is Need for welding?

With ever increasing demand for both high production rates and high precision, fully mechanized or automated welding processes have taken a prominent place in the welding field. The rate at which automation is being introduced into welding process is astonishing and it may be expected that by the end of this century more automated machines than men in welding fabrication units will be found. In addition, computers play critical role in running the automated welding processes and the commands given by the computer will be taken from the programs, which in turn, need algorithms of the welding variables in the form of mathematical equations. To make effective use of the automated systems it is essential that a high degree of confidence be achieved in predicting the weld parameters to attain the desired mechanical strength in welded joints. 2 To develop mathematical models to accurately predict the weld strength to be fed to the automated welding systems has become more essential.

Classification of welding

There are many types of welding techniques used to join metals. The welding processes differ in the manner in which temperature and pressure are combined and achieved.

The welding process is divided into two major categories:

  • Fusion Welding (General classification shown in figure 1) and
  • Pressure Welding (Classification shown in figure 2).
Fusion Welding classification
Figure 1, Fusion Welding classification​
 Fusion Welding classification​
Figure 2, Pressure welding classification

Figure 3 shows the classification of various welding processes as defined by the American Welding Society (AWS).

 Fusion Welding classification​

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