Automobile Condenser Vacuum Brazing

As shown in the picture, the condenser is used for automobile air conditioner, its structure is vacuum brazed heat sink on aluminum flat tube, and the material is LF21. It is clamped by four frame clamps and two pressure plates when assembling. Choose a foil -shaped BAl9OSiMg solder with a thickness of 0.1mm.

Figure 1 Condenser for car air conditioner

Before brazing, clean the aluminum flat tube, guard plate and heat sink in NaOH solution, degrease the foil solder in HNO3 solution, polish with 100 grit sandpaper, and then assemble it with a fixture. Brazing adopts a three-stage pump vacuum, three -stage temperature control SIMUWU dedicated horizontal cold wall vacuum furnace. In order to make the furnace temperature uniformity meet the requirements of brazing aluminum, three voltage regulators are used to control the temperature in three stages, and vacuum to 4X10-3MPa; heat to 550 °C at a rate of 10~15°C/min and hold for 5 minutes; Heating at a rate of 7°C/min to 620°C, heat preservation at 620°C ± 5°C for 3mins, power off and cooling to below 500°C with the furnace, fill with high-purity nitrogen, and start the fan to quickly cool down to 65°C before leaving the furnace; Visually inspect the brazing joint Completeness after the brazing finished.