Braze Welding Aluminium Alloy

Brazed aluminum base solder material and aluminum alloy brazing plate. When brazing, the brazing material is not melted, and the solder is melted and filled to connect the workpiece. Aluminum alloy brazing sheet can be made by coating aluminium-based filler metal on aluminium alloy core material, which is widely used in heat exchangers.




The Al Si alloy with Al based filler metal has low melting point and good fluidity and is suitable for brazing filler metal. The typical aluminum base filler metals are 4343, 4045 (American brand) and 4004 alloy. Its main chemical compositions and properties are listed in Table 1. The 6951 (American grade) alloys in industrial pure aluminum, aluminum manganese alloys and aluminum-magnesium-silicon alloys have good brazing properties, and they can be brazed with the above-mentioned aluminum-based solders. Aluminum-magnesium-silicon alloys 6061, 6053 (American grade) and 6063 also have better brazing properties, but because their initial melting temperature is lower than that of industrial pure aluminum and Aluminum-Manganese alloys, the brazing temperature should be strictly controlled to prevent overburning. 4004 filler metal contains magnesium, which is suitable for vacuum brazing. In the brazing process, magnesium vapor reacts with residual oxygen and water in the furnace to purify it. Magnesium vapor also inhibits the re-oxidation of brazed aluminum alloy.
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Aluminum alloy brazed sheet is usually composed of Aluminum-Manganese alloy (3A21, 3003) core material and aluminum-based brazing filler metal cladding. The grades and chemical compositions of Chinese aluminum alloy brazed sheet are listed in Table 2. The manufacturing process is that the aluminum-based solder plate is placed on one or both sides of the core ingot, preheated to the hot rolling temperature (about 500 C), hot-rolled, and then cold-rolled into a thin plate, and the cladding layer is completely pressed onto the core material. The thickness of the coating is 5% to 15% of the thickness of the core.

Aluminum alloy brazing plate is usually used as brazing alloy for brazing assembly.Brazed aluminum base solder and aluminum alloy brazing plate. When brazing, the brazing material is not melted, and the solder is melted and filled to connect the workpiece. Aluminum alloy brazing sheet can be made by coating aluminium-based filler metal on aluminium alloy core material, which is widely used in heat exchangers.