Aluminum Brazing Material Matrix and Cladding metal

Optimization of Aluminum Alloy Brazing Material Matrix and Cladding Metal and Optimization of Metallurgical Quality

The composition and metallurgical quality of matrix and cladding metal are the key factors that affect the welding performance of aluminum alloy cladding/brazing sheet (foil). The chemical composition of matrix and cladding material must be designed according to the needs of the market, and the metallurgical quality optimization work should be carried out.



1. Brazing Welding Aluminum Alloy Matrix material
　　From the point of view of brazing, it is desirable that the matrix of the aluminum alloy cladding/brazing sheet (foil) is made of a brazing alloy with a cladding layer (solder), a high melting point and plasticity, and an aluminum alloy in which the brazing filler metal is not too largely diffused, that the aluminum alloy which is not easily eroded by the molten solder is used as the base material. Aluminum alloys belonging to this type include pure aluminum, AL-Mn alloys, and Al-Mg-Si-Cu alloys containing magnesium content of 1% or less. At present at home and abroad using vacuum fluxless brazing process to produce heat exchangers -base materials are mostly used 3003 and 6951 alloy.

Metallurgical quality optimization, the use of new aluminum casting, strictly control the  scrapto add, to strengthen the furnace refining and on-line degassing slag, to avoid excessive matrix in the brazing of low melting point compounds and oxide film defects. Because of the inherent factors of melting, the ingot surface and head and tail uniformity are worth than the ingot core , these areas are prone to segregation, slag and other defects. Through the sampling and analysis of the ingot head and surface quench zone, the scope of the area was clarified, and the corresponding process was established. The sawing volume of the ingot was not less than 150mm, and the ingot surface of the ingot was not less than 10mm.

Brazing Welding Aluminum Alloy Cladding material
Al-Si alloys commonly used in cladding materials, such as 4004,4045,4047,4343, etc., its role is to be remelted at around 600 ℃ high temperature, to solder the 3003 matrix and aluminum foil fins together. In this process, the brazing layer plays a vital role. When welding, the Si element melts at high temperatures, and the Mg element is blasting, causing the flow of Si to flow evenly with the substrate and the aluminum foil fins. Therefore, the Mg element plays an important role,if the Mg content in the cladding plate is low, the flow of the brazing layer is not good, which is easy to cause the cold solder joint, the Mg content is high, the blasting is violent and the base material is likely to be destroyed. According to a large number of experimental studies, Si content control in the center line is ideal.