General Characteristics

Technically pure copper has high thermal and electrical conductivity and fairly high corrosion resistance. It is very resistant to atmospheric corrosion due to the formation of a protective thin film on its surface which consists of C2O oxide. Copper is not the strongest metal, but it is very ductile. The ductility of copper increases up to 62% as the gas content decreases. At high temperatures, the strength of copper decreases, while ductility increases. An important property of copper is its ability to maintain ductility up to liquid helium temperature of -269°C.

Overview of methods

The most widely used method of soldering is soldering with gas burners, in furnaces, by soldering iron or by dipping into molten solder. Brazing with low temperature brazing alloys is very common, because of the accessibility and simplicity of this method. The only reason for some limitations is that a soldering iron can only be used at temperatures up to 350°C for thin-walled parts. Large parts are soldered with gas torches because of their high thermal conductivity, which is six times that of iron. Cadmium brazing alloys require special skills, since their processability is significantly lower than that of tin-lead brazing alloys.

Immersion method

Used to braze copper tube heat exchangers. They are immersed in solder melts and salts. This brazing method usually uses salt bath furnaces in salt melts. The salts usually serve as a source of heat with a fluxing action, and no additional fluxing is required. During soldering by immersion with solder in the bath, the pre-fluxed parts are heated in the solder melt, which fills the connecting gaps at the soldering temperature. Inert gas or activated carbon protects the brazing mirror. Soldering in salt baths has a disadvantage - in some cases it is impossible to remove flux or salt residue.

Brazing in furnaces

Widely spread in industry as it provides even heating without deformation of soldered items even if they have big dimensions.

Solders and fluxes

Soldering with lead-tin and other high-fusing solders on copper items, as a rule, involves the use of aqueous solutions of ammonium chloride or zinc chloride, as well as rosin-alcohol fluxes. Silver brazing is successful with potassium fluoride and boron-based fluxes.

Vacuum brazing

Used to join copper to other metals. This method of brazing is completely safe, quite economical and is carried out in containers or vacuum furnaces, which are loaded into conventional furnaces.

Buy, price

Evek GmbH stocks a wide range of copper and copper alloy products at optimal prices. We appreciate our customers' time, so we are always ready to help with the best choice. Experienced consulting managers are at your service. The quality of our products is guaranteed by our strict adherence to production standards. The terms of fulfilling orders are minimal. Wholesale customers receive preferential discounts.