Technically pure copper has high conductivity, electrical conductivity and relatively 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 oxide Си2О. Copper is the most durable, but very ductile metal. Plasticity with a decrease of gas content in copper increases to 62%. At high temperatures decreases the strength of copper, and the ductility on the contrary increases. An important property of copper — the ability to maintain plasticity to the temperature of liquid helium -269°C.
A review of methods
The most widely used method of soldering is a soldering gas burners, ovens, soldering iron or by immersion in the molten solder. Great use is made of soldering with low temperature solders, due to the accessibility and simplicity of this method. Some limitations in the use of such soldering due only to the fact that with a soldering iron, soldering can be carried out at temperatures up to 350 °C only for thin-walled parts. Large parts solder gas burners, due to the large thermal conductivity that exceeds six times the conductivity of iron. For use cadmium solders requires special skill, as their adaptability is much lower tin-lead.
The immersion method
Used for soldering copper tube heat exchangers. They are immersed in the molten solders and salts. In such soldering, usually use salt furnace bath in a molten salt. Usually salts are a source of heat, providing a fluxing action, and for more flucomune is not required. During the soldering process by dipping the solder in the bath, ofljusovannyh preliminary parts are heated to melt the solder filling at the temperature of soldering connecting the gaps. Inert gas or charcoal protect the mirror of the solder. Soldering in salt baths has the disadvantage — in some cases impossible to remove flux residues or salts.
Widespread in industry, because in this case uniform heating without deformation of the solder products even with their large dimensions.
Solders and fluxes
When soldering tin-lead and other fusible alloys of copper products generally used aqueous solutions of ammonium chloride or zinc chloride, and rosin-alcohol fluxes. Brazing with silver solder successfully suitable for use on the basis of fluorides of potassium and boron compounds and fluxes.
Soldering in vacuum
Used for joining copper with other metals. This soldering method is completely safe, fairly economical and is carried out in containers or in vacuum ovens, which are loaded in a conventional oven.
To buy, price
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