Innovative Casting Technology Offers Advantages for Aluminum brazing Sheet Used in Heat Exchangers

摘要

Thus far, several hundred commercial-sized ingots with many different alloy combinations have been successfully produced for brazing sheet and other novel end uses. Novelis engineers have found that increased ingot size (690 X 1750 mm), and the thermal economies that size offers, makes them easier to manage from a thermo-mechanical perspective during solidification. Similarly, while every alloy combination has its own challenges and nuances, any increase offered in the temperature differentials of the two alloys or in the sequence of solidification when approaching identical alloys will contribute to the overall probability of success in the cast/clad package. Fortunately, brazing combinations have this solidification differential naturally built in. Novelis is clearly committed to the new technology. The first Novelis Fusion facility, located in Oswego, N.Y., was commissioned in March 2006 to meet the market demand for commercialized brazing products. Success has been directly tied to a unique relationship between the sales/ marketing, production and technology sectors coupled with a desire to improve the market offering for brazed products from its business partners downstream of the core-rolling processes. At writing, virtually all of the company's traditional clad material in North America has been converted to the new technology. Subsequently, announcements of investments in casting facilities in Switzerland (September) and South Korea (November) were made. Brazing sheet manufactured with Novelis Fusion technology meets or exceeds all criteria necessary for customers to produce strong, durable and corrosion-resistant heat exchangers. The advantages to the new-technology brazing sheet include reduction in lead time (two to four weeks), cladding uniformity that allows for down gauging, and a clean and oxide-free clad/ core interface. Even more encouraging, Novelis Fusion technology opens the door for greater alloy development for the next generation of products.