Cold Welding

Cold welding is the process of welding metals without applying any heat and with the parts to be joined in a completely solid-state. It is a mechanical engineering process and we will detail everything in this post.

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Types of Cold Welding

This welding has two basic types:

  • Cold Welding that involves machines.
  • The other requires special products.

Cold welding with machines

Cold welding is based on the application of certain pressure and vacuum conditions that make it possible to join metals without melting them, at room temperature.

In essence, we carry out the welding at low temperatures by means of equipment that exerts pressure on the pieces that we will join. In doing so, we eliminate the barrier between one and the other through rollers or dies and as a result we join the electrons. It is very useful because it does not alter the properties of the elements.

It is a process that dates back to 1724 when they managed to join small lead balls by pressing them together. There are even traces of cold welding of this type in the 700s, applied to gold. However, it was in 1940 when they realized its usefulness through studies conducted at the time.

Today, cold welding by pressure uses the principle of multiple upsetting, in machines with a die where the two pieces are inserted until they are soldered.

Conditions to carry out the welding in low temperatures with machines

Cold welding must meet certain requirements in order to be carried out:

  • The material of at least one of the elements to be joined must be capable of being deformed.
  • The process takes place under vacuum conditions and, the pressure is such that an interaction occurs between free electrons and ionized atoms, which makes fusion possible.
  • The metals must be free of grease and oxide. It is recommended to use a wire brush to clean them.

Cold welding is applied to small, mouldable, non-ferrous, and carbon-free metals (copper and aluminum), as well as to electrical cables and connections, transistors, and electronic components.

Welding in low temperatures with special products

It is the most common and widespread cold welding, popular for DIY tasks. Although it is also used in professional areas such as the automotive industry.

These are its advantages:

  • It is used to repair and glue all types of metals.
  • It is low cost and fasts to perform.
  • There is a diversity of products in the market, easy to acquire, and specially designed for metals and aluminum.
  • Depending on the product, cold welding can fix up to 100 kilograms of weight per square meter.
  • Some brands such as Pattex, Wurth, and Ceys have cold welding options that guarantee results in just five minutes. They can even fill cracks or holes and act as a protective film against rust.

It is in high demand in vehicle repair, since it is resistant to high temperatures and the action of solvents and oils, and it is also useful in masonry to repair pipes.

How to apply cold welding with special products?

It is required: clean the surfaces to be welded and apply an anti-corrosion layer to improve the product’s fixation.

Each brand has its own particular instructions, but generally, its different components must be mixed and this preparation must be placed in the area where the joint will be made.

There is a determined time to do this process before it solidifies. This period is about 40 minutes for the mixture and about three hours for its handling.

Then, it is molded and, once hardened, the area can be sanded to eliminate imperfections, as well as polished, painted, and give the metal the treatment we require.

It is important to give it enough time to solidify. We suggest at least 12 hours.

There are other types of weldingin low teperatures like a special adhesive material to join the two pieces you need. It is useful for pipes. In some cases, you can include reinforcement tape to further fix the weld.

When choosing your cold welding product, check the manufacturer’s specifications well: application times, instructions, materials where it works, its resistance. This way you will be able to obtain the best results according to the applications you will give it.

Robert

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