WELDING AND ITS EVOLUTIONS
What can be welded?
The metal materials that are most traditionally welded are steel and aluminium, nickel and titanium alloys.
The only polymeric materials that can be welded are thermoplastics.
What types of welding are there?
Welding processes have evolved and adapted to the development of materials and production technologies.
The first steps in welding
The first attempts at welding date back to the Middle Ages, when there was still no scientific knowledge to optimise it. Blacksmiths melted metal in furnaces, where the joints were welded evenly through the prolonged use of the metal. This welding technique was laborious, dirty and unrefined; the result was quite rough and did not comply with current standards. The method was similar to that used in Japan to produce the famous katanas.
When was electric welding invented?
In 1877, the American engineer Elihu Thomson invented the first welding system, which worked by clamping
the parts to be welded between two copper electrodes that were heated by passing electric current through them. The two metals were heated, and therefore melted, at the point to be welded by means of electrodes.
Later, at the beginning of this century, electric arc welding was introduced. In electric arc welding, the welder manoeuvres an electrode through which a high-voltage current passes, which reaches the two parts to be welded, forming an arc at a very high temperature. To form a continuous joint where the metal is molten, more metal is added, forming a single joint.
The main types of electric arc welding are:
manual with coated electrode (MMA)
submerged arc welding (SAW)
continuous wire welding with shielding gas (MIG/MAG)
with shielding gas and with an infusible electrode (TIG)
How has welding evolved since then?
To complete electric arc welding, the automatic welder was invented, which, with the arrival of shielding gases, enabled underwater welding, which is of higher quality and resistant to corrosion.
Today, there are many other welding techniques, such as laser welding, microplasma welding, FSW, etc., but the most widespread and reliable method remains the traditional arc welding.