High frequency induction aluminum brazing

High frequency induction aluminum brazing

High frequency induction heating machines were once considered impossible to connect aluminum and aluminum alloys through brazing, but with the emergence of new brazing fluxes and methods, they have now been widely used, such as manufacturing aluminum heat exchangers, waveguide components, turbine impellers, connecting busbars and conductors through brazing.

Compared with other metal brazing, the brazing of aluminum and aluminum alloys first involves the formation of a dense and chemically stable oxide film on the surface of aluminum. The thickness is usually 2-5nm at room temperature, and can reach over 100nm when heated at high temperatures of 500 ℃. If we don't try to destroy this oxide film, we won't be able to use a high-frequency induction heating machine for brazing.

Secondly, the melting point of aluminum and aluminum alloys is relatively low, and the suitable aluminum brazing material has a higher melting point. Therefore, when brazing with hard brazing material, the melting point of the brazing material is not significantly different from that of the base material, so the brazing temperature must be strictly controlled. Another difficulty in manual flame brazing of aluminum and aluminum alloys is that the melting point of the aluminum oxide film is much higher than that of the base metal, and the colors of the two are similar, making it difficult to determine the heating temperature by observing the heating color of the base metal. For heat treated reinforced aluminum alloys, annealing or aging may occur after brazing, resulting in a decrease in the strength of the base material. In addition, when brazing with soft solder, the corrosion resistance of the joint is poor due to the significant temperature difference between the solder and the base metal.

Therefore, when selecting brazing materials for aluminum and aluminum alloys, careful selection should be made based on the characteristics of various brazing materials; In addition, only when an appropriate amount of brazing material is used can a good brazing effect be achieved. Too little brazing material can cause poor spreading of the brazing material; Too much brazing material may cause excessive corrosion of the aluminum alloy base material. On thin composite components, the use of brazing material requires more appropriate amount.

Our company can provide a complete set (induction heating equipment+automation+brazing materials) of low-temperature brazing solutions for aluminum aluminum and copper aluminum joints of various heat exchangers and radiators.