Aluminum alloy brazing fin material for heat exchanger

Abstract

An aluminum alloy brazing fin material for an automobile heat exchanger, which comprises a core material and, being clad on the both surfaces thereof, an Al-Si based alloy brazing material, characterized in that the above core material is composed of an aluminum alloy having a chemical composition that Mn: 0.8 to 2.5 %, Si: 0.1 to 1.0 %, Fe: 0.06 to 0.3 %, Zn: 0.8 to 4.0 % and the balance: Al and impurities, and the above brazing material is composed of an aluminum alloy having a chemical composition that Si: 6 to 13 %, Cu: 0.06 to 0.4 % and the balance: Al and impurities, and that the brazing material is clad on both surfaces of the core material with a thickness of 3 to 20 % of the total thickness, respectively. The above aluminum alloy brazing fin material for an automobile heat exchanger exhibits excellent formability and excellent corrosion resistance even under a severe corrosion circumstance.

Description

technical field [0001] The present invention relates to an aluminum alloy brazing fin material for heat exchangers, in particular to a radiator, heater core, oil cooler, intercooler, condenser and evaporator of a vehicle air conditioner, etc. Aluminum alloy brazing fin materials for aluminum alloy heat exchangers, which are formed by joining fins and aluminum tubes (including aluminum alloy tubes) constituting the working fluid passage by brazing, particularly relating to a solder fillet Aluminum alloy brazed heat sink material with excellent corrosion resistance. Background technique [0002] Aluminum alloy heat exchangers are widely used as heat exchangers for automobiles such as radiators, heater cores, oil coolers, intercoolers, and evaporators and condensers of vehicle air conditioners. These aluminum alloy heat exchangers are manufactured by forming a brazing sheet in which an Al-Si alloy brazing filler metal is coated on a core material of an Al-Mn alloy such as JISA...

AI Technical Summary

Problems solved by technology

However, when a heat exchanger for an automobile is prepared by brazing and joining a fin material formed by brazing on an aluminum tube body coated with Zn, the welding legs between the aluminum tube body and the fins are corroded, although the fins The corrosion is slight, but sometimes the separation of the aluminum tube body and the heat sink will result in a problem that the heat transfer performance of the heat exchanger is reduced.

[0005] On the other hand, in recent years, the dust produced by the tires with anti-skid punctures of automobiles has a health hazard. Therefore, studless anti-skid tires are used instead of tires with anti-skid punctures. The braking performance on icy roads is poor. Therefore, in winter when snow is accumulated and the road is icy, in order to prevent the car from slipping, a large amount of deicing agent such as calcium chloride or sodium chloride is sprayed on the road.

Since these deicing agents are attached to the heat exchanger of a moving car, the corrosion of the heat exchanger is promoted. Therefore, the aluminum tube body and the heat sink are separated prematurely, and the heat sink falls off in severe cases.

[0006] In addition, the heat exchanger is painted after brazing, and in order to improve the sealability of the coating film and enhance the corrosion resistance, the surface of the aluminum parts constituting the heat exchanger is treated with dichromate or phosphoric acid chromate. However, Due to environmental concerns, chromate treatment was abolished, therefore, the progression of solder fillet corrosion became faster and the heat sink became easier to separate from the aluminum tube body