Vacuum Brazing of Aluminum (Report-II) : Effect of Emery Paper Grinding
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Vacuum brazing of aluminum with BA 4047 (Al-12%Si filler alloy) can be performed by an inserted type brazing method, in which the filler alloy is preset between the vertical and horizontal members of tee type joint. Grinding by emery papers of 80-600 grade is recommended for the surface pretreatment. On the other hand, grinding by fine emery papers (1500 grade) causes the contamination of surface layer by inclusion of emery paper component SiC and showed poor fillet forming. The decrease in brazability by inclusion appears to be the scarce reaction between the filler alloy and SiC. For the estimation of brazability in preplaced filler alloy method, some parameters are discussed. The ratio of vertical leg length (L_V) to horizontal leg length (L_H) is adopted as a convenient and clear parameter. A spreading test is useless for estimating the ability of fillet formation.
- Transactions of JWRI
Transactions of JWRI 7(1), 135-141, 1978-06