Welding Equipment:
an Overview

Technologies

Specialized equipment is required for performing Welding operations.
Every specific process is applied using dedicated equipment,
from single use hand held welding torches to completely automatic robotic cells.
Equipment is also needed for preparation processes, for heat treatments, for testing and for inspection.

Some of the equipment is universal and can be used for very different applications.
Other types are more suitable to the specific requirements of well defined situations.
This website page describes some general characteristics of certain types of equipment.

Given the abundance of different types of processes for performing basic welding of elements on scores of different materials, the selection of the most economic solution likely to provide acceptable results becomes a difficult art, mostly performed with success only by knowledgeable and expert welding engineers.

Electric Welding Equipment

Electricity is needed for providing energy to different types of welding technologies:

Magnetic pulse welding is a cold weld process that realizes welding  by accelerating one part against the other with much force to induce joining by interpenetration.

Ultrasonic welding is another cold welding method that needs electricity to energize one element on top of another through an ultrasonically vibrating implement called horn.

The most common and known processes are called resistance welding processes, with a few variants, and arc or plasma welding processes that concentrate the energy displayed by an arc or plasma with or without the addition of filler metal in a small spot to be moved along the welding joint.

Heating by High Frequency Induction the facing sides of a plate rolled to tubular form and then applying compression is a common technology for tube manufacturing.
Several variants of special equipment were developed to fill the requirements of special applications.

Other welding processes revive the oldest process called forge welding where parts of elements heated to the highest temperatures were hammered together, by pressing the surfaces of heated  elements one against the other.

These processes, collectively called upset welding, depend on external heating of the surfaces to be pressed together: heating can be achieved by gas flames or by electrical means like flash, meaning local discharges over a small gap, sufficient to heat a small volume of material on both sides.

Welding follows when the heated parts are pressed together under forces sufficient to create a displacement, called upset, like that obtained in forge welding.

Stud welding joins small parts like bolts, nuts, collars and similar elements of mechanical fastening devices onto surfaces, in given places, by specific equipment that heats the abutting surfaces by generating flashes between the parts and the surface, just before pressing those in place to generate upset welding.

Friction welding equipment, which exploits friction heat generated by mechanical fretting requires electric power to generate the relative movement of the parts.
Standard friction welding generates heat by displacing two surfaces in contact, one still, the other moving.
Friction stir welding uses a special revolving and moving tool to transform solid metal in a plasticized moving material mass that produces something similar to a forging to join two elements.
Remarkable success was achieved by NASA in the construction of space vehicles by this FSW process.

High energy electron beams and laser beams are relatively recent developments that enjoyed extremely successful applications.

Different forms of Additive Manufacturing generate geometric bodies by adding by welding tiny bits of material one at a time in a programmed sequence to build complex structures that are much more difficult and expensive to realize by traditional subtractive technologies.

Gas welding equipment

Practical success and diffusion were achieved by using oxy-fuel flames long before electricity was available and universally distributed.
Portability was the main advantage as sets of the needed equipment could be made small enough for personal carrying and self contained work.
A basic outfit of this kind is always present for urgent repair work in the simplest shop and in the most sophisticated industry.

Equipment is needed for generating, for transporting, for storing and for distributing combustible gas to the point of use.
Suitable torches are used for manipulating flames for the purpose of heating, cutting, welding, bending, straightening, brazing or weld-brazing.

Chemical Energy Welding Equipment

The two most diffused processes making use of chemical energy are Explosive Welding and Thermite Welding.

The first one, involving explosion of charges, is performed in caves or isolated areas with all the precautions needed not to harm people.
Equipment is quite simple but most of the attention is devoted to safety in use.

The other one, consisting in special melting equipment and molds has the remarkable property of portability, in that all needed elements do not require external sources of energy.
This process is mostly used for welding rails head to head.
Safety is as always a very important consideration.

Equipment

The list of Equipment described in this website is given in the Index-Welding-Page.

Under the same heading as here above, one can find a long list of Equipment whose title describes the content of the relevant page,  that is displayed by clicking on the active link.

All the pages published in the website are listed also in the Site Map.