Study On Preparation And Performance Of The Radiator Solder

Radiator has two types of aluminum- copper and pure aluminum, due to the sharp ly rising price of copper, the cost of using copper is increased. At present, many domestic and international researchers carry on a great deal of empirical research on using aluminum instead of copper, and achieve remarkable results. Air conditioning, automotive aluminum heat exchanger, radiator and aluminum cables have been widely used. Aluminum radiator usually adopts 3003 aluminum alloy as radiating fins, the rolling foil for brazing filler metals, but traditional foil can not meet the complex surface of brazing matrix metal. With the proposing of lightweight, traditional foil thickness has reached the bottleneck, can not meet the requirement of lightweight. In this paper, in order to solve the problem of brazing combination of radiator, the two kinds of different melting point of solder are prepared, respectively Al-8Si solder is 585℃ and low- melting Zn-15 Al solder is 385℃, the brazing layer is prepared on the surface of 3003 aluminum alloy by spraying technology and coating thickness can reach micron-scale or nanoscale, lower than the traditional foil and meet the requirement of lightweight. Differential scanning calorimeter and scanning electron microscopy are used to investigate the melting temperature, microstructure of solder and bracing joint, and study the effect of brazing process on brazing joint.This thesis studies the best technology of preparing the Al-8Si wire solder and optimal parameters for arc spraying of preparing the bracing coating, Zn-15 Al alloy powder prepares coating process parameters for plasma spraying. The wetting angles of Al-8Si and Zn-15 Al on the surface of 3003 aluminum alloy are 10° and 10.5°. The thesis studies the brazing temperature and holding time on joint interface element distribution changes of the solder coating and the 3003 substrate by EDS, to analyze the distribution of elements effect on brazed bond strength. Al-8Si solder at 620℃ brazing 20 minutes, part of the matrix metal is melted. During the bracing process, Si diffuses from brazing filler metal to weld seam, the matrix Al diffuses to weld seam, α-Al solid solutions gradually form a network structure in the weld, the hard Si phase evenly distributes around α-Al solid solution, improving the bonding strength of the weld.The best brazing temperature of Al-8Si solder is 610℃, heat preservation for 30 minutes, brazing bond strength is best, fracture morphology of bracing joint pr esents ductile fracture characteristics. Bracing Zn-15 Al solder coating at 430℃, Zn violently spreading to the weld, excessive Zn in the weld hinders solder spreading on the surface of 3003 aluminum alloy, reducing liquidity and brazing combine with poor performance. The best brazing temperature of Zn-15 Al solder is 410℃, heat preservation for 30 minutes, coating and substrate combined.