Today, aluminum radiator manufacturer Zhaogong Technology will talk to you about the analysis of the influencing factors on vacuum brazing of aluminum alloy plate radiators

Abstract: This article introduces the vacuum brazing process of aluminum alloy plate heat sinks; Systematically analyzed factors such as material composition, coating thickness, surface pre-treatment, seal shape, surface roughness, radiator assembly, vacuum brazing temperature, insulation time, vacuum argon arc welding, and environment that affect the welding quality of the radiator

The influence of factors such as surface roughness of the radiator assembly, vacuum brazing temperature, insulation time, vacuum argon arc welding, and environment on the welding quality of the radiator; Corresponding process measures have been proposed and have achieved good results in engineering practice.

The so-called vacuum brazing refers to holding the materials to be brazed together with fixtures, heating them in a vacuum furnace to melt 4004, 4104, or 4N04 aluminum alloy solder into a high-temperature liquid, and filling the gaps between the welded parts (3003 alloy) under capillary force to achieve metallurgical bonding. Vacuum brazing belongs to ultra-high vacuum airtight welding, which can braze materials and structures that are difficult to connect using ordinary methods, and obtain smooth and dense brazing joints with excellent mechanical properties and corrosion resistance. Compared with other welding methods, its advantages are small deformation of parts, the ability to connect multiple parts simultaneously, and the ability to connect different metal materials.

Vacuum brazing of aluminum plate radiators requires high requirements for surface roughness, assembly quality, fit tolerance, brazing system, etc. of the parts before brazing, and is prone to defects such as false soldering, fin bending and lodging, corrosion, discontinuous brazing joints, and leakage. Among them, the main defect is that the brazing area of the large seal is prone to severe leakage during pressure testing, and 40% of the welded body needs to be reworked, repaired, or repaired. This article systematically analyzes the reasons for the leakage of the large sealing strip of aluminum alloy plate radiators, points out the links that should be paid attention to in production, provides a theoretical basis for improving the qualification rate of secondary pressure of radiators, and has achieved good results in engineering practice.

1. Structure and production process of radiator

1.1 Structure of radiator

The structure of the aluminum plate heat sink is shown in Figure 1, mainly composed of large seals, small seals, 434 composite plates (partitions), outer fins, inner fins, side plates, and guide fins.

1.2 Production process flow

The production process of radiators: material preparation -+acid and alkali washing ->assembly of heat dissipation components ->vacuum furnace high-temperature brazing -+shaping -+argon arc welding guide plate ->pound pressure test -+rework and repair -+surface spraying -+finished product packaging.

Material preparation: cut 434 composite Flat noodles, inner fins and outer fins, and prepare large seals, small seals and side plates. Acid alkali washing: alkali washing -+water washing -+acid washing -+water washing -+hot water washing ->drying.

Assembly process of heat dissipation components: side plate -+bottom layer composite plate - → outer layer fins -+enlarged seals at both ends -+- sheet composite plate+reduced seals on both sides -+inner layer fins -+- sheet composite plate - → outer layer fins -+enlarged seals at both ends -+top layer composite plate -+side plate.

Vacuum furnace brazing: The vacuum brazing furnace generally adopts a three-stage heating and insulation process (Figure 2), which includes pre vacuuming -+the first stage preheating at a constant temperature of 400~425C, insulation for 60~80min -+the second stage energy storage at a constant temperature of 560~575C, insulation for 40~60min -+the third stage brazing at a constant temperature of 602~609 C, insulation time of 30~40min - →+power outage and waiting for the air temperature in the furnace to drop to 350~400 C before being discharged.

Heat sink shaping: Due to a certain amount of deformation of the heat sink after brazing, an external force shaping method is used to flatten it, making its unevenness ≤ 2 mm. Argon arc welding guide plate: The guide plate is welded to the large sealing strip at both ends of the radiator.

The above is the analysis of the influencing factors on vacuum brazing of aluminum alloy plate radiators compiled by Zhaogong Technology. We hope it will be helpful to everyone. Guangdong Zhaogong Technology Co., Ltd. is a professional enterprise that researches, produces, and sells various specifications of aluminum profiles, aluminum radiators, and aluminum parts. The products are widely used, including the lighting industry, industrial industry, decoration industry, automotive parts, daily necessities, furniture, etc.

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