Process of making a shaped product
A process of making a shaped product consisting of aluminium or an aluminium alloy comprising the steps of producing an intermediate object by extrusion or rolling and having at least one flat surface, coating the at least one flat surface with a brazing flux retaining coating which is composed of flux particles and a binder containing at least 10% by weight of a synthetic resin based, as its main constituent, on methacrylate homopolymer or a methacrylate copolymer, reshaping of the intermediate object into the shaped product and heating the shaped product to a temperature sufficient to provide at least one brazed connection between defined parts of the shaped products.
1. A process of making a shaped product comprising the steps of:
providing an intermediate object formed of aluminum or an aluminum alloy to have at least one flat surface
coating the at least one flat surface with a flux composition to form a coating on the at least one flat surface, the flux composition comprising particles of a braze flux material and a binder containing at least 10% by weight of synthetic resin based, as its main constituent, on methacrylate homopolymer or a methacrylate copolymer, wherein the weight ratio of the braze flux material to the synthetic resin in the flux composition is in the range from 9:1 to 3:2,
reshaping the intermediate object into the shaped product, and
heating the shaped product to a temperature sufficient to provide at least one brazed connection between portions of the shaped product.
2. A process according to claim 1 , wherein the reshaping step comprises a bending operation of at least one part of the flat surface of the intermediate object.
3. A process according to claim 1 , wherein the reshaping step causes the at least one flat surface and the coating thereon to be deformed to yield a deformed portion to which the coating remains adhered.
4. A process according to claim 1 , wherein the flux composition contains a pre-flux composition and is used in combination with a preclad material on the intermediate object.
5. A process according to claim 1 , wherein the heating step causes the synthetic resin to volatilize.
6. A process according to claim 3 , wherein the amount of flux material is selected in such a way that the coating contains an amount of free Si, Zn or Zn+Si within the range 1 to 7 g/m 2 .
7. A process according to claim 1 , wherein the flux material is based upon a fluoroaluminate compound.
8. A process according to claim 1 , wherein the shaped product is a folded tube.
9. A process according to claim 1 , wherein the shaped product is a welded tube.
10. A process according to claim 1 , wherein the shaped product is a wrapped tube.
11. A process according to claim 10 , wherein the shaped product is a manifold tube.
12. A process of making a tubular-shaped product comprising the steps of:
producing an intermediate object by extruding or rolling aluminum or an aluminum alloy to have at least one flat surface;
coating the at least one flat surface with a flux composition to form a coating on the at least one flat surface, the flux composition comprising particles of a flux material and a binder containing at least 10% by weight of synthetic resin based, as its main constituent, on methacrylate homopolymer or a methacrylate copolymer,
reshaping the intermediate object into the tubular-shaped product so that the at least one flat surface and the coating thereon are deformed to yield a deformed portion to which the coating remains adhered, the coating being present between the deformed portion and a second portion of the tubular-shaped product; and
heating the tubular-shaped product to a temperature sufficient to volatilize the synthetic resin and produce at least one brazed connection between the deformed and second portions of the tubular-shaped product.
13. A process according to claim 12 , wherein the weight ratio of the flux material to the synthetic resin in the flux composition being in the range from 9:1 to 3:2.
14. A process according to claim 12 , wherein the tubular-shaped product is a heat exchanger tube.
15. A process according to claim 12 , wherein the tubular-shaped product is a heat exchanger manifold tube.
16. A process of making a tubular component of a heat exchanger, the process comprising the steps of:
providing an intermediate object formed of aluminum or an aluminum alloy to have at least one flat surface;
coating the at least one flat surface with a flux composition to form a coating on the at least one flat surface, the flux composition comprising particles of a braze flux material and a binder containing at least 10% by weight of synthetic resin based, as its main constituent, on methacrylate homopolymer or a methacrylate copolymer;
reshaping the intermediate object into a tubular object so that the at least one flat surface and the coating thereon are deformed to yield a deformed portion to which the coating remains adhered; and
heating the tubular object to a temperature sufficient to volatilize the synthetic resin and provide at least one brazed connection between portions of the tubular object and thereby yield the tubular component.
17. A process according to claim 16 , wherein the weight ratio of the flux material to the synthetic resin in the flux composition is in the range from 9:1 to 3:2.
18. A process according to claim 16 , wherein the flux material contains free Si, Zn, or Zn+Si.
19. A process according to claim 16 , wherein the tubular component is a heat exchanger tube.
20. A process according to claim 16 , wherein the tubular component is a manifold tube.