Methods and technologies of aluminum soldering

Soldering Difficulties

The surface of aluminum and its alloys is covered by a strong oxide film due to its light oxidation, which makes soldering difficult. An additional difficulty is that the soldering points are prone to corrosion. Soldering can be facilitated by plating copper or nickel on aluminum in advance. Places of soldering are etched with sulfuric acid, caustic soda solution, followed by rinsing in water, and then subjected to nickel plating or copper plating in the galvanic bath. Surfaces covered with a film of nickel or copper are soldered with ordinary soft solders. But the electroplating method is complicated, time consuming and quite expensive. Usually they simply strip the edges before soldering and use special solders for soldering rolled aluminum - most often technically pure zinc. When soldering by rubbing it gives a joint strength of about 9 kg/mm², but such joints corrode quickly. Solder one and solder two give a tensile strength of at least 10 kg/mm². Solder three is particularly ductile and has considerable relative elongation; its strength limit is about 8 kg/mm². Solder four is prone to brittleness, but gives a joint strength of up to 20 kg/mm². Note that the strength of the solder joint increases as the melting temperature of the solder increases.

Percentage composition of aluminum solder

Composition of fluxes and solders

Rosin, stearin, powdered sugar are used for fluxes. Preliminary solder is rubbed on the surface with a brush or scraper. For overlap connections sometimes powdered zinc chloride is used as solder. Powder of dry zinc chloride is poured on the surface cleaned for soldering and heated. The zinc chloride melts, releasing acrid smoke. As a result of the exchange reaction, aluminum combines with chlorine and evaporates, and molten zinc fuses with aluminum, penetrating the surface layer. Thus, the surface is deburred with zinc, and the parts are joined with the zinc-aluminum alloy.

Optimization of soldering

Heating the overlapped and tinned parts together produces a corrosion resistant and durable bond. Harder brazing requires more refractory brazing alloys and special fluxes. A special solder for aluminum, for example, consists of 25-30% copper, 4.7% silicon and the rest aluminum. The solder melts at 525 °C and is used together with a flux of lithium chloride 25-30%; potassium fluoride 8-12%; zinc chloride 8-15% and potassium chloride - the rest. The flux melts at 450 °C. This solder and flux provides a strong brazing of aluminum.

Supplier

Supplier Auremo offers to buy aluminum in bulk or in installments. Large selection of semi-finished products in stock, a wide range of fluxes and solders. The best price of aluminum from the supplier. Buy aluminum today. For wholesale customers - the price of aluminum rolled. Courier service will deliver your order as soon as possible. Buy aluminum from "Auremo". The best price of aluminum and aluminum alloys from the supplier.

Buy Auremo's best price.

Supplier "Auremo" is a recognized expert in the non-ferrous metals market. Thanks to our representative offices in Eastern Europe we have the possibility of operative cooperation with our trade partners. Auremo" company's experience allows you to buy aluminum alloys. In assortment any structural materials. From us it is easy to buy aluminum in bulk, or by installments. Auremo" company is a reliable supplier of aluminum, we invite everyone to partner cooperation. We have the best price-quality ratio. Wholesale customers - preferential price of aluminum. All products are certified. Buy aluminum, the best price in this segment.