The development of metal welding, the history of welding?

Welding is an indispensable process in the automotive industry, which uses pressurization, heat, or a combination of both to permanently join the workpiece. Especially in the body, frame, engine and other large parts have a pivotal position, and resistance welding has the characteristics of large production capacity, small welding deformation, high efficiency, easy operation, high degree of automation, low energy consumption, etc., which is more suitable for the welding of automobile body sheet and its parts. Therefore, the purpose of this project is to ensure the welding quality of product parts while optimizing parameters, reducing energy consumption and equipment loss, and improving economic benefits.

1. Experimental principle: Resistance welding is a welding process in which the welded workpiece is pressed between two electrodes, and then a certain current is applied, and the resistive thermal effect generated when the current flows through the contact surface or adjacent area of the workpiece is used to heat the workpiece to a molten or plastic state to form a metal bond. There are four main types of resistance welding: spot welding, seam welding, projection welding, and butt welding.

Projection welding is mainly used for welding stamping parts of low carbon steel and low alloy steel. There are many types of projection welding, in addition to projection welding of plates, there are also projection welding of nuts and screws, cross-projection welding of wires, projection welding of pipes and T-shaped projection welding of plates, etc. As a kind of resistance welding, nut spot welding, i.e., projection welding, has the following multiple advantages:

Multiple solder joints can be welded simultaneously in a single soldering cycle, with high productivity and no shunts. High current densities can be welded with a small current, and a small nugget is formed. The position of the bump is accurate, and the strength of each point is relatively uniform.

It can reduce the indentation on the exposed surface of another workpiece. Bumps are used to confine current and pressure to specific locations on the workpiece, and their shape and size depend on the application and the strength of the solder joints required. In general, small bumps are used when the plate is thinner, and large bumps are used when it is thicker.

A short time should be used for projection welding of mild steel nuts, otherwise the thread will be discolored and the accuracy will be reduced; The electrode pressure should also not be too low, otherwise it will cause the bumps to shift, reduce the strength, and damage the threads.

Before the end of the 19th century, the only welding process was the forged welding of metal, which had been practiced by blacksmiths for hundreds of years.

The earliest modern welding techniques appeared at the end of the 19th century, first with arc welding and oxy-gas welding, and later with resistance welding.

In the early 20th century, the demand for military equipment in World War I and World War II was great, and the corresponding cheap and reliable metal joining process was emphasized, which in turn promoted the development of welding technology.

After the war, several modern welding techniques emerged, including manual arc welding, which is currently the most popular, as well as automatic or semi-automatic welding techniques such as MIG/MAG arc welding, submerged arc welding (submerged arc welding), flux-cored wire arc welding, and electroslag welding.

In the second half of the 20th century, welding technology developed rapidly, and laser welding and electron beam welding were developed.

Today, welding robots are widely used in industrial production.

History of Welding More than 3000 BC, forging welding technology appeared in Egypt. More than 2,000 years BC, China's Yin Dynasty used casting and welding to manufacture weapons. Before 200 B.C., China had mastered the brazing of bronze and the forging and welding of iron.

1801: The arc was discovered in England.

Welding is an important part of the manufacturing industry, and the rapid development, so to the welding industry has brought unprecedented development opportunities, welding, argon arc welding, welding and other technical types of work in the increasingly difficult employment situation is still outstanding, so it has attracted many people to choose to enter the welding industry. Because people see the bright employment and development of the welding industry, the employment prospects of the welding profession are very good!

The development prospects of welding in the future are also very good, and they are more inclined to automation and intelligence.