Aluminum radiator vacuum brazing process

Fri Sep 23 10:55:13 CST 2022

Compared with copper radiators, aluminum heat exchange radiators used for hydraulic oil cooling on vehicles such as automobiles and engineering vehicles have higher heat dissipation efficiency, lower weight and cost, and are widely used. The all-aluminum heat exchanger follows the characteristics of the copper radiator and uses the serpentine tube structure, which is assembled by hydraulically assembling the aluminum tube mechanical expansion tube and the heat sink. With the invention of NOCOLOK non-corrosive flux welding process and environmental protection requirements In order to ensure that the heat exchange efficiency does not decrease, the brazing aluminum plate-fin structure radiator came into being. [0 003] The brazing process of aluminum heat sinks includes (1) salt bath welding: molten salt removes the oxide layer on the surface so that the molten solder metal can flow and wet out, but the residual bath salt has a strong effect on aluminum [0 003] Corrosive, the removal process is complicated and there are residual hidden dangers; (2) Vacuum brazing technology: under vacuum conditions, the high-temperature liquid solder fills the solid base metal gap to be welded under the action of capillary force, and is added to the brazing material. Magnesium, the cost is cheaper and the process is cleaner. There is no waste generated during the brazing process, and there will be no oxidation, coupling, decarburization, deterioration and other phenomena. However, because magnesium condenses in the vacuum furnace wall, it needs to be shut down for cleaning. , the existing vacuum brazing curve is shown in Figure 1, and the production efficiency is low; (3) CAB gas shielded welding: welding with gas shielded solder to wet the master batch aluminum material to protect the oxidation at the welding place, compared with vacuum brazing Higher production efficiency but higher cost and uneven gas shielding resulting in less strength and cleanliness than vacuum brazing

. an aluminum radiator vacuum brazing process, it is characterized in that, its process steps are as follows: (1) the brazing filler metal is assembled on the part to be brazed of the aluminum radiator part, and put into the vacuum brazing furnace, close the furnace door And vacuumize; (2) The vacuum brazing furnace is heated in a gradient continuous curve for vacuum brazing. The first stage of the vacuum brazing furnace is heated to 515~525°C at a constant speed in 30min, and then cooled to 420~440°C in 60min. C, then the constant temperature holding time is less than or equal to 60min, and the vacuum degree of the vacuum brazing furnace is higher than 10-1Pa; (3) the second stage of the vacuum brazing furnace is heated to 570~580°C at a constant speed in 30min, and then the constant temperature holding time is less than or equal to 60mi n, the vacuum degree of the vacuum brazing furnace is higher than 10-1Pa and lower than 10-2Pa; (4) The third stage of the vacuum brazing furnace is heated to 610~615°C at a constant speed for 20min, and then the constant temperature is kept for less than or equal to 60min, and the cooling Cooling is less than or equal to 70min, the termination temperature of cooling and cooling is 560~580°C, and the vacuum degree of the vacuum brazing furnace is higher than 10-2Pa; (5) After the vacuum brazing is completed, open the furnace door, take out the brazed aluminum radiator and put it in the furnace. Check it out. 2. The vacuum brazing process for an aluminum radiator according to claim 1, wherein the vacuum brazing furnace is less than the maximum set temperature when heating up, and the vacuum brazing furnace alarms when the temperature exceeds the maximum set temperature