METHOD FOR BRAZING AND USE OF A BRAZING FOIL FOR INDUCTION BRAZING
A method for brazing is provided, in which an amorphous or partially amorphous brazing foil, having a composition with a metalloid content of 10 to 30 at. %, is arranged at a joining point of two or more parts. The brazing foil is in the form of a wound ring-shaped strip which has a short-circuited current path between at least two layers lying one on top of the other. The brazing foil inductively heated, melted and a brazed connection of the parts is produced.
1 . A method for brazing, having the following steps:
arranging an amorphous or partially amorphous brazing foil, having a composition with a metalloid content of 10 to 30 at. %, at a joining point of two or more parts, wherein the brazing foil is in the form of a wound ring-shaped strip which has a short-circuited current path between at least two layers lying one on top of the other,
inductive heating the brazing foil,
melting the brazing foil, and
producing a brazed connection of the parts.
2 . A method according to claim 1 ,
wherein
firstly the brazing foil is wound around the joining point and then a short-circuited current path is produced between at least two layers of the brazing foil lying one on top of the other.
3 . A method according to claim 1 ,
wherein
firstly a wound ring-shaped strip is produced with a short-circuited current path between two layers, lying one on top of the other, of the brazing foil, in order to produce a wound ring-shaped strip as a braze part, and then the braze part is arranged around the joining point.
4 . A method according to claim 1 ,
wherein
a premanufactured wound ring-shaped strip with a short-circuited current path between two layers, lying one on top of the other, of the brazing foil is provided and the premanufactured ring-shaped strip is arranged at the joining point.
5 . A method according to one claim 1 ,
wherein
the short-circuited current path is produced by welding, spot welding, crimping or a mechanical connection of at least two overlapping layers of the wound ring-shaped strip.
6 . A method according to claim 1 ,
wherein
the wound ring-shaped strip has at least two windings.
7 . A method according to claim 6 ,
wherein
at least two adjacent windings are in electrical contact with each other.
8 . A method according to claim 6 ,
wherein
all windings are short-circuited by means of a common electrical connection with each other.
9 . A method according to claim 6 ,
wherein
a plurality of windings are short-circuited by means of a common electrical connection with each other.
10 . (canceled)
11 . A method according to claim 1 ,
wherein
at least the brazing foil and the joining point are heated in a vacuum or an inert gas.
12 . A method according to claim 1 ,
wherein
the brazing foil and the joining point are locally heated.
13 . A method according to claim 1 ,
wherein
an induction coil is arranged around the joining point.
14 . A method according to claim 13 ,
wherein
the parts are brazed using an induction brazing process.
15 . A method according to claim 1 ,
wherein
the wound ring-shaped strip is arranged outside, inside or between two or more parts.
16 . A method according to claim 1 ,
wherein
the brazing foil and the joining point are inductively heated to a temperature above a liquidus temperature of the brazing foil and are cooled, with a brazed joint thereby being formed between the parts.
17 . A method according to claim 1 ,
wherein
the first part and the second part are each composed of a chromium-containing stainless steel, such as an austenitic stainless steel, or a Ni alloy or a Co alloy.
18 . A method according to claim 1 ,
wherein
the brazing foil comprises an iron-, nickel- or cobalt-based brazing foil.
19 . A method according to claim 18 ,
wherein
the brazing foil comprises at least 3 at. % chromium.
20 . A method according to claim 1
wherein
the ductile brazing foil comprises a chromium-free brazing foil.
21 . A method according to claim 1 ,
wherein
the brazing foil provided comprises a copper-based brazing foil.
22 . A brazing foil for induction brazing,
wherein
the brazing foil is an amorphous or partially amorphous brazing foil with a metalloid content of 10 to 30 at. % and has the form of a wound ring-shaped strip which has a short-circuited current path between two layers lying one on top of the other.
23 . A brazing foil according to claim 22 ,
wherein
the brazing foil comprises an iron-, nickel- or cobalt-based brazing foil.
24 . A brazing foil according to claim 23 ,
wherein
the brazing foil comprises a chromium content of at least 3 at. %.
25 . A brazing foil according to claim 22 ,
wherein
the brazing foil comprises a copper-based brazing foil.
26 . A brazing foil according to claim 22 ,
wherein
the brazing foil is arranged at a joining point of parts of a heat exchanger, a metallic catalyst or an exhaust gas system or a metallic particulate filter or a fuel line, and the parts are brazed using an induction brazing process.
27 . A method for induction brazing, having the following steps:
providing an amorphous or partially amorphous brazing foil with a metalloid content of 10 to 30 at. % and having the form of a wound ring-shaped strip which has a short-circuited current path between two layers lying one on top of the other, and
inductive heating the brazing foil.