Cold welding of metal

Cold welding is a technological process that involves plastic deformation of the joining surfaces of parts without any additional heating from an external heat source. Plastic deformation occurs at the junction of the workpieces through compression or shear. Welding occurs instantaneously, without diffusion.

Cold metal welding diagram

Cold welding of metal is a relatively old phenomenon and likely dates back to ancient times. Before the welding process, the metal surface must be thoroughly cleaned. No adhesive is used; it is a purely mechanical joining process. A special device is used to induce simultaneous deformation and increasing stress, which forms a monolithic joint. The physical and chemical state of the metal determines the quality of the weld.

Quality is also affected by the deformation pattern and the method of applying the force, which can be vibrational or static. Cold welding of metal, depending on the deformation method, can be seam, spot, or butt. This type of welding is applicable to lead, copper, aluminum, zinc, silver, nickel, and other metals.

Application of cold welding for metal It's justified when conventional welding poses a risk of warping. It's also preferred by welders when the risk of internal stress is high.

Cold welding can be used when working with very large metal parts. Since this type of welding does not heat the material, it is used, for example, when repairing tanks containing explosive substances.

Cold welding of metals under pressure

Cold pressure welding of metals has a significant advantage over other welding methods in that it seamlessly and successfully welds dissimilar metals that are sensitive to heat or form intermetallic compounds. It is not a traditional welding process; the joining process occurs through the mechanical action of the metal mass and its penetration into the surfaces of the other metal being joined.

A monolithic weld is formed through deep plastic deformation. This deformation causes the oxide layer on the surfaces being welded to break down, bringing the metals closer together, and the distance between them becomes very close to the dimensions of the crystal lattice. The increase in the energy level of the atoms on the surfaces being welded causes the formation of chemical bonds, strengthening the bond between the workpieces. The mechanical properties of the metal are not affected.

The essence of the process of cold welding of metals under pressure is as follows:

The metal rods to be welded are installed in the steel clamping jaws of the cold welding machine and clamped using a specific technology;
the clamped rods begin to connect with each other, deform at the ends, taking with them oxide films that interfere with the process of welding two metals;
At the end of the welding process, the jaw knives close and trim off any unnecessary roughness that has formed.

Such a machine for cold welding of metals under pressure is the "MSKHS-120.03M.UKHL4" brand, which welds copper plates, aluminum, copper with aluminum.

Another welding machine for cold welding of metal It's called the SDHB-5. It can weld steel, cast iron, and aluminum products. Cold welding machine for metal Suitable for both experienced and novice welders, it doesn't require extensive welding experience. The machine is ideal for spot welding, creating a neat yet strong weld on the material.

Cold pulse welding for metalUnlike conventional cold welding, cold pulse welding melts the material. The heat source is a pulsed arc. It's called "cold" welding because the pulsed arc is formed intermittently. This allows the welder to better control the heat input. Using medium currents results in smooth, spatter-free welding. The risk of material deformation is also significantly reduced. Cold pulse welding is most often used to join aluminum alloys thicker than 1.5 mm. It is also suitable for working with special steels thicker than 1 mm.

Advantages of cold welding:

no powerful electrical energy source required;
clean seam, not contaminated with impurities;
high homogeneity of metals at the weld joint;
good corrosion resistance.

Flaws:

a small range of materials that can be connected, only those with high plasticity;
high metal consumption for welding allowance.

Cold welding of metals under pressure There's one important feature that every craftsman should remember. To ensure a reliable seam, the surfaces being joined must be perfectly clean. Even if you simply touch the surface with your hands, it's important to thoroughly clean it afterwards.

The main application of this type of welding is in the electrical industry of various types.