Method for producing a roll-clad aluminum workpiece, roll-clad aluminum workpiece, and use therefor

Abstract

A method for producing a roll-clad aluminum workpiece and an associated roll-clad aluminum workpiece are provided, wherein a core ingot is produced from an aluminum alloy and at least one cladding piece is produced from a cladding material, wherein at least one groove is introduced into the core ingot and/or into a layer applied to the core ingot, wherein the cladding piece is inserted into the groove, and wherein the core ingot is hot-rolled after the cladding piece has been inserted, the width of the groove being equal to or less than the core ingot width. A use of such a roll-clad aluminum workpiece is also provided for producing a soldered workpiece, in particular a folding tube.

Claims

1. A method of producing a folded tube from a roll-clad aluminum workpiece, in which a core ingot of an aluminum alloy and at least one cladding piece of a cladding material are provided, in which at least one groove is incorporated into the core ingot and/or into a layer which may have been applied to the core ingot, in which the cladding piece is inlayed into the groove, in which the core ingot, after inlaying of the cladding piece, is hot-rolled to produce a roll-clad aluminum workpiece, and in which the roll-clad aluminum workpiece is folded such that the at least one cladding piece forms a joint section with another region of the roll-clad aluminum workpiece so as to form the folded tube, wherein the width of the groove is equal to or less than 70% of the core ingot width, and wherein the cladding piece is composed of a brazing alloy.

2. The method according to claim 1, wherein the at least one cladding piece has a width equal to or less than 50% of the core ingot width.

3. The method according to claim 1, wherein the cladding piece is composed of an alloy of the type AA 4xxx.

4. The method according to claim 1, wherein the cladding piece is adapted so as to exactly fit the shape of the groove.

5. The method according to claim 1, wherein the cladding piece which is inlayed into the groove is spaced apart from the longitudinal edges of the core ingot.

6. The method according to claim 1, in which a first cladding piece of a cladding material and a second cladding piece of a cladding material are provided, in which at least one first groove is incorporated into the core ingot and/or into a layer which may have been applied to the core ingot, in which the first cladding piece is inlayed into the first groove, in which the second cladding piece is inlayed into the first or into a second groove which is incorporated into the core ingot and/or into a layer which may have been applied to the core ingot, and in which the core ingot, after inlaying of the first and second cladding piece, is hot-rolled.

7. The method according to claim 6, wherein the first cladding piece is composed of a first cladding material, and the second cladding piece is composed of a second cladding material which is different from the first cladding material.

8. The method according to claim 6, wherein the first cladding piece has a first thickness, and the second cladding piece has a second thickness which is different from the first thickness.

9. A method, comprising the steps of: producing a folded tube from a roll-clad aluminum workpiece, the roll-clad aluminum workpiece having a core of an aluminum alloy, and having at least one cladding layer of a cladding material on one side of the aluminum workpiece, the at least one cladding layer configured to form a joint section with another portion of the roll-clad aluminum workpiece when the roll-clad aluminum workpiece is folded into a folded tube, wherein the cladding layer extends across only a part-region of the side of the aluminum workpiece wherein the part-region occupies at maximum 70% of the entire area of the side, and that the cladding layer is composed of a brazing alloy.

10. The method according to claim 9, wherein the part-region of the side of the aluminum workpiece, across which the at least one cladding layer of the aluminum workpiece extends, has a size equal to or less than 50% of the entire area of the side of the aluminum workpiece.

11. The method according to claim 9, wherein the cladding layer is composed of an alloy of the type AA 4xxx.

12. The method according to claim 9, wherein the aluminum workpiece has at least one brazing point for brazing the aluminum workpiece, that the cladding layer is a brazing cladding layer, and that the part-region, across which the cladding layer extends, is adapted to the location of the at least one brazing point.

13. The method according to claim 9, wherein the aluminum workpiece on one side has a first cladding layer of a cladding material, and a second cladding layer of a cladding material, and that the first cladding layer extends only across a first part-region, and the second cladding layer extends only across a second part-region of the side of the aluminum workpiece.

14. The method according to claim 13, wherein the first cladding layer is composed of a first cladding material, and the second cladding layer is composed of a second cladding material which is different from the first cladding material.

15. The method according to claim 1, wherein the at least one cladding piece has a width equal to or less than 25% of the core ingot width.

16. The method according to claim 1, wherein the cladding piece which is inlayed into the groove is spaced at least 2 cm apart from the longitudinal edges of the core ingot.

17. The method according to claim 9, wherein the part-region of the side of the aluminum workpiece, across which the at least one cladding layer of the aluminum workpiece extends, has a size equal to or less than 25% of the entire area of the side of the aluminum workpiece.

18. A folded tube, comprising a roll-clad aluminum workpiece having a core of an aluminum alloy, and having at least one cladding layer of a cladding material on one side of the aluminum workpiece, the at least one cladding layer forming a joint section with another portion of the roll-clad aluminum workpiece, wherein the cladding layer extends across only a part-region of the side of the aluminum workpiece wherein the part-region occupies at maximum 70% of the entire area of the side, and that the cladding layer is composed of a brazing alloy.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages and features of the invention emerge from the following description of further exemplary embodiments, reference being made to the appended drawings in which:

(2) FIGS. 1a)-d) show a first exemplary embodiment of the method for producing a roll-clad aluminum workpiece, and of the roll-clad aluminum workpiece;

(3) FIGS. 2a)-b) show a core ingot having cladding pieces, and a roll-clad aluminum workpiece produced therefrom, as a second exemplary embodiment of the method and of the roll-clad aluminum workpiece;

(4) FIGS. 3a)-b) show a core ingot having a layer applied thereonto and having cladding pieces, and a roll-clad aluminum workpiece produced therefrom, as a third exemplary embodiment of the method and of the roll-clad aluminum workpiece;

(5) FIGS. 4a)-b) show a roll-clad aluminum workpiece and an integral multi-chamber folded tube produced therefrom as a fourth exemplary embodiment of the roll-clad aluminum workpiece, and as an exemplary embodiment of the use; and

(6) FIGS. 5a)-b) show a roll-clad aluminum workpiece and an integral multi-chamber type-B folded tube produced therefrom, as a fifth exemplary embodiment of the roll-clad aluminum workpiece, and as an exemplary embodiment of the use.

DETAILED DESCRIPTION OF THE INVENTION

(7) FIG. 1 shows an exemplary embodiment of the method according to the invention. To this end, the part FIGS. 1a)-1d) show a core ingot, or an aluminum workpiece produced therefrom, respectively, at various temporal points of the method. FIGS. 1a)-1d) in each case show a plan view and a cross section (along the sectional line which is marked in the plan view in FIG. 1a).

(8) FIG. 1a) shows a core ingot 2 of an aluminum alloy, which has been provided for the method. In the present example, a groove 4 which is bilaterally continuous is milled into the core ingot 2. In FIG. 1b) the groove 4 has a rectangular shape. However, alternatively other shapes and/or a groove which is unilaterally or bilaterally offset are/is also conceivable.

(9) Furthermore, a cladding piece 6 of a cladding material is provided for the method, for example by being sawed from a sheet of cladding material, and is inlayed into the groove 4, as is illustrated in FIG. 1c). The cladding piece 6 is adapted to exactly fit the shape of the groove 4, that is to say that the cladding piece 6 is likewise rectangular, and the length and width of the cladding piece 6 are substantially congruent with the length and width of the groove 4. Moreover, in the present exemplary embodiment the thickness of the cladding piece 6 is congruent with the depth of the groove 4. The cladding piece 6 thus completely fills the groove 4.

(10) The core ingot 2 having the cladding piece 6 which is inlayed into the groove 4 is subsequently hot-rolled to form the aluminum workpiece 7 which is illustrated in FIG. 1d). On account of hot rolling, the cladding piece 6 is clad onto the core ingot 2, that is to say is connected thereto in a materially-integral, force-fitting, and/or form-fitting manner. The aluminum workpiece 7 thus has a core 8 of an aluminum alloy and a part-area cladding layer 10.

(11) FIG. 2 shows a second exemplary embodiment of the method and of the roll-clad aluminum workpiece.

(12) A core ingot 22 of an aluminum alloy is illustrated in cross section, so as to be transverse to the longitudinal extent of the core ingot 22, in FIG. 2a). Grooves 24a-e have been milled into the core ingot 22, into which grooves cladding pieces 26a-f have been inlayed. Subsequently, the core ingot 22 having the cladding pieces 26a-f has been hot-rolled to form the aluminum workpiece 27 which is likewise illustrated in cross section in FIG. 2b). The aluminum workpiece 27 has a core 28 of an aluminum alloy, and part-area cladding layers 30a-f which correspond to the cladding pieces 26a-f.

(13) The grooves 24a,c,d,e, and the cladding pieces 26a,d,e,f, are measured such that the cladding pieces in each case fit exactly into the corresponding grooves. The groove 24b and the cladding pieces 26b,c are measured such that both cladding pieces fit into the groove so as to be beside one another. Furthermore, the grooves 24a,b have the same depth, such that cladding layers 30a,b,c, of equal thickness are produced. The grooves 24c,d,e, likewise have the same depth, the latter however being larger than the depth of the grooves 24a,b. On account thereof, comparatively thick cladding layers 30d,e,f, may be produced.

(14) The cladding piece 26d has a resistance to forming which is similar to that of the core ingot 22, while the cladding piece 26e has a resistance to forming which is lower than that of the core ingot 22, and the cladding piece 26f has a resistance to forming which is higher than that of the core ingot 22. On account of the different resistances to forming, during hot rolling the cladding piece 26e having the lower resistance to forming is subjected to a larger reduction in thickness, and the cladding piece 26f having the higher resistance to forming is subjected to a smaller reduction in thickness than the core ingot 22. In order to nevertheless obtain a substantially planar surface in the aluminum workpiece 27 and in order to reduce warping during the rolling process, the thickness of the cladding piece 26e is selected to be larger, and the thickness of the cladding piece 26f is selected to be smaller than the depth of the groove. The thicknesses of the cladding layers 30d,e,f, which have been obtained from these cladding pieces 26d,e,f, are illustrated to be of similar size in FIG. 2b; however, depending on the material of the cladding piece, or of the core 28, respectively, they may also be differently sized or shaped.

(15) In principle, the cladding pieces 26a-f may be composed of the same cladding material or of different cladding materials. The properties of the aluminum workpiece 27 may be adjusted to requirement by way of the selection of the cladding material for the individual cladding pieces 26a-f. In particular, an aluminum workpiece 27 having different locally-focused properties may be produced. For example, the cladding piece 26a may be composed of a solder cladding material, so as to produce a locally-focused solder cladding layer 30a. The cladding pieces 26b-c may have different visual properties, for example be matt and brilliant, so as to achieve a visual effect of the cladding layers 30b-c. A corrosion-resistant alloy may be used for the cladding piece 26d, for example, so as to provide a locally-focused corrosion-resistant cladding layer 30d. In principle, the combination possibilities of the various cladding materials and cladding layer thicknesses as well as of the number of cladding layers and of the arrangement of the cladding layers are unlimited.

(16) FIG. 3 shows a third exemplary embodiment of the method and of the roll-clad aluminum workpiece. The illustration corresponds to the illustration in FIG. 2.

(17) The core ingot 42 which is illustrated in FIG. 3a differs from the core ingot 22 in FIG. 2a in that another layer 43 has been applied onto the core ingot 42. This layer 43 may be a holohedral cladding layer, which has been clad onto the core ingot 42 in a first hot-rolling pass, for example. Alternatively, the layer 43 may also be adhesively bonded or brazed onto the core ingot.

(18) Grooves 44a-i have been incorporated into the layer 43 and/or into the core ingot 42. The depth of the grooves 44a-d here is smaller than the thickness of the layer 43, such that the grooves effectively have only been incorporated into the layer 43. In contrast thereto, the depth of the grooves 44c-e is larger than the thickness of the layer 43, such that the grooves have been incorporated both into the layer 43 as well as into part in the core ingot 42.

(19) Cladding pieces 46a-f have been inlayed in the grooves 44a-e. The aluminum workpiece 47 which is illustrated in FIG. 3b has been produced by hot-rolling the core ingot 42 having the layer 43 and the cladding pieces 46a-f. Said aluminum workpiece 47 has a core 58 of an aluminum alloy, cladding layers 50a-f which correspond to the cladding pieces 46a-f, and a cladding layer 49 which is substantially holohedral, with the exception of the region of the cladding layers 50d-f.

(20) The cladding layers 50a-c lie above the cladding layer 49, such that multiple cladding results here. This is also referred to as multicladding.

(21) FIG. 4 shows a roll-clad aluminum workpiece and an integral multi-chamber folded tube produced therefrom as a fourth exemplary embodiment of the roll-clad aluminum workpiece and as exemplary embodiment of the use.

(22) The aluminum workpiece 62, which in FIG. 4a is illustrated in cross section transverse to the longitudinal extent, has a core 64 of an aluminum alloy, and first cladding layers 66a-d of a first cladding material, and second cladding layers 68a-c of a second cladding material. The first cladding material is solder cladding layers, while the second cladding material is a corrosion-resistant alloy. The aluminum workpiece 62 may have been produced by one of the afore-described methods, for example.

(23) The multi-chamber folded tube 70, which is illustrated in cross section in FIG. 4b, has been produced by forming the aluminum workpiece 62. The location of the first cladding layers 66a-d of the aluminum workpiece 62, that is to say of the solder cladding layers, here is precisely such that the latter in the multi-chamber folded tube 70 lie in the joint regions 72a-b, in particular in the base point of the joint region 72b. On account thereof, the multi-chamber folded tube 70 may be brazed in the joint regions 72a-b. In contrast thereto, the second cladding layers 68a-c, that is to say the corrosion-resistant cladding layers, are disposed such that they line the internal cross sections 74a-b of the multi-chamber folded tube 70. On account thereof, corrosion resistance of the multi-chamber folded tube 70 in relation to the media routed through the internal cross sections 74a-b is enhanced.

(24) FIG. 5 shows a roll-clad aluminum workpiece and an integral multi-chamber type-B folded tube produced therefrom as a fifth exemplary embodiment of the roll-clad aluminum workpiece, and as an exemplary embodiment of the use.

(25) The aluminum workpiece 82, which in FIG. 5a is illustrated in cross section transverse to the longitudinal extent, has a core 84 of an aluminum alloy and cladding layers 86, 88 of a solder cladding material. The part-area cladding layer 86 is disposed on one side of the core 84, and the holohedral cladding layer 88 is disposed on the other side of the core 84. The aluminum workpiece 82 may have been produced by one of the afore-described methods, for example.

(26) The multi-chamber type-B folded tube 90, which is illustrated in cross section in FIG. 5b, has been produced by forming the aluminum workpiece 82. The location of the cladding layer 86 of the aluminum workpiece 82 here is precisely such that the latter in the multi-chamber folded tube 90 lies in the joint region 92 at the base points of the wings 94a-b. On account thereof, the base points of the wings 94a-b may be brazed to the inside of the opposite wall, without a holohedral solder coating in the interior or the application of a brazing paste being required for this purpose. Furthermore, on account of the cladding layer 88, the wings 94a-b can be brazed to one another in a two-dimensional manner at their lateral areas.

(27) Improved workpieces, such as, for example, the multi-chamber folded tube 70 or the multi-chamber folded tube 90, may be economically produced using an aluminum workpiece such as the aluminum workpiece 62 or the aluminum workpiece 82, which on account of the cladding layers 66a-d and 68a-c or 86, respectively, which in part are of different types, has locally-focused different surface properties.