ISSN: 1003-6326
CN: 43-1239/TG
CODEN: TNMCEW

Vol. 30    No. 12    December 2020

[PDF]    [Flash]
Effect of brazing parameters on fillet size and microstructure of cladded fin-microchannel tube joints
J. C. GUíA-TELLO1, M. I. PECH-CANUL2, E. TRUJILLO-VáZQUEZ3, M. A. PECH-CANUL4
(1. Centro de Investigación en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnología, Miguel de Cervantes No. 120, Chihuahua, Chih., 31136, México;
2. Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional-Unidad Saltillo, Av. Industria Metalúrgica No.1062, Parque Industrial Saltillo-Ramos Arizpe, Ramos Arizpe, Coahuila, 25900, México;
3. CONACYT-Facultad de Ciencias Físico Matemáticas, Benemérita Universidad Autónoma de Puebla, Av. San Claudio, Cd Universitaria, Jardines de San Manuel, Puebla, Puebla, 72570, México;
4. Cinvestav-Mérida, Km 6 ant. Carr. a Progreso, AP 73 Cordemex, Mérida, Yuc., 97310, México
)
Abstract: This work concerns the optimization of furnace brazing conditions for joining micro-multiport aluminum tubes and fins made with AA4343/AA3003/AA4343 brazing sheet in mini-assemblies mimicking the core of an automotive heat exchanger. Taguchi method was used for design of experiment, considering five process parameters with two levels of values. The aim was to maximize the fillet size of the brazed joints, which has an important influence on the thermal integrity and mechanical properties. Fillet length measurements of brazed joints were performed with a metallographic microscope. The statistical analysis allowed to obtain the optimum values of process parameters (peak temperature, residence time, heating rate, microchannel tube type and flux). At a 95% confidence level, the variability of fillet length is most significantly affected by the peak brazing temperature (77%), residence time (15%) and heating rate (7%). The predicted maximum fillet length was (152±11) μm, which was corroborated by confirmation trials. The microstructural analysis of tube-fin joints showed that variations in peak temperature and residence time affect only the size of the eutectic zone of fillet formed, but not the nature or composition of the constituent phases.
Key words: brazing; cladded fin; Taguchi method; fillet size; microstructure; aluminum; peak temperature; optimization
Superintended by The China Association for Science and Technology (CAST)
Sponsored by The Nonferrous Metals Society of China (NFSOC)
Managed by Central South University (CSU) 湘ICP备09001153号-9