(19)
(11)EP 0 227 261 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
27.12.1989 Bulletin 1989/52

(21)Application number: 86308368.9

(22)Date of filing:  28.10.1986
(51)International Patent Classification (IPC)4C22C 21/00, C22C 21/08, B23K 35/24, B23K 35/28, C22F 1/04, C22F 1/047, C22F 1/043

(54)

Corrosion-resistant aluminium core alloy

Korrosionsbeständige Aluminiumkern-Legierung

Noyau à base d'un alliage d'aluminium résistant à la corrosion


(84)Designated Contracting States:
DE ES FR GB IT SE

(30)Priority: 06.12.1985 US 805533

(43)Date of publication of application:
01.07.1987 Bulletin 1987/27

(73)Proprietor: KAISER ALUMINUM & CHEMICAL CORPORATION
Oakland California 94643 (US)

(72)Inventor:
  • Finnegan, Walter D.
    Walnut Creek California 94598 (US)

(74)Representative: Ackroyd, Robert et al
W.P. THOMPSON & CO. Eastcheap House Central Approach
Letchworth, Hertfordshire SG6 3DS
Letchworth, Hertfordshire SG6 3DS (GB)


(56)References cited: : 
DE-A- 3 244 634
US-A- 3 857 165
GB-A- 939 417
US-A- 4 284 437
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    BACKGROUND OF THE INVENTION


    1. Field of the Invention



    [0001] This invention relates to aluminum alloys, and particularly to aluminum alloys used in corrosive environments.

    2. Description of the Relevant Art



    [0002] Aluminum has long been known for its resistance to corrosion, a property which renders it a favorable material of construction for a wide variety of purposes. In particular, it has gained wide acceptance in the manufacture of heat exchangers such as, for example, automotive radiators and evaporators for air conditioning units. Depending on the type of exchanger, the parts may be joined together by welding or brazing.

    [0003] Despite aluminum's inherent corrosion resistance, corrosion still occurs. This is particularly true in materials joined by brazing, since the brazing operation causes intergranular penetration of the core material by certain species in the brazing alloy, notably silicon. When the brazed product is subjected to a corrosive environment, the intergranular regions in the core, where silicon is present in high concentrations, are particularly susceptible to corrosion. In automotive radiators, for example, where the brazing alloy is present only on the exterior surface of the tubes, the salts and moisture from the road are sufficiently corrosive to cause attack from the outside, resulting ultimately in pinhole formation.

    [0004] This problem has been addressed in the literature in a variety of ways. An early example is Miller, U.S. Patent No. 2,821,014 (January 28, 1958), where it is disclosed that intergranular corrosion problems in flux and dip brazing are alleviated by adding an inter layer between the structural member portion and the brazing layer. The interlayer is aluminum or an aluminum-base alloy, particularly certain magnesium- containing alloys, having a melting point greater than that of the structural alloy. The solution offered by Singleton et al., U.S. Patent No. 3,788,824 (January 29, 1974) and its divisional, No. 3,881,879 (May 6, 1975), is directed to vacuum brazing, and involves the addition of iron to either the core alloy or the cladding alloy as an alloying element, resulting in improvements in both corrosion resistance and sag resistance.

    [0005] Anthony et al., U.S. Patent No. 4,039,298 (August 2, 1977) address both flux and vacuum brazing, and disclose a composite of complex and highly specified composition as being particularly beneficial in terms of corrosion properties. The disclosed core alloy contains specified amounts of manganese, copper, chromium, silicon and iron as alloying elements with both a solid solution and an alpha-phase, whereas the alloying elements in the cladding are bismuth and silicon. An additional disclosure by the same patentees appears in U.S. Patent No. 4,093,782 (June 6, 1978) and its continuation-in-part, No. 4,167,410 (September 11, 1979), in which the core alloy contains a specified combination of chromium and manganese, with resultant improvements in both corrosion resistance and sag resistance.

    [0006] A still further disclosure by the same patentees appears in U.S. Patent No. 4,209,059 (June 24, 1980), where a conventional core alloy is clad with a brazing alloy on one side and a "sacrifical cladding layer" on the other, the result being a lessening of crevice corrosion between the aluminum header plate and the plastic tank in an automobile radiator. A "sacrificial anode" effect is disclosed in Tanabe et al., U.S. Patent No. 4,317,484 (March 2, 1982), and Terai et al., U.S. Patent No. 4,203,490 (May 20, 1980), for tube-and-fin heat exchangers by incorporating tin and zinc into the fin core material and manganese into the tube material. A similar differentiation between fins and tubes is disclosed in Kanada et al., U.S. Patent No. 4,410,036 (October 18, 1983), whereby the fins are provided with a lower electrochemical potential.

    [0007] Setzer et al., U.S. Patent No. 3,994,695 (November 30, 1976), disclose a core alloy which con- tains a chromium-manganese-zirconium combination, the sole claimed benefit however being an improvement in sag resistance. Sag resistance is also addressed by Toma et al. in U.S. Patent No. 4,511,632 (April 16, 1985), where manganese, silicon and zinc are included in the cladding layer. A combination of copper and titanium as primary alloying elements in the core alloy is disclosed in Kaifu et al., U.S. Patent No. 4,339,510 (July 13, 1982), as providing a benefit in intergranular corrosion resistance.

    [0008] A different approach is disclosed by Nakamura, U.S. Patent No. 4,172,548 (October 30, 1979), in which corrosion following fluxless brazing processes in general (including both vacuum brazing and brazing in an inert atmosphere) is controlled by controlling the grain size of the brazing sheet to at least 60 microns in diameter, achieved by a controlled cold work followed by a full anneal.

    [0009] Thus, with the exception of Nakamura, existing solutions generally involve the introduction of specific elements in the alloy compositions. Processing modifications have also been used to similar effect, notably that disclosed in copending, commonly owned application Serial No. 634,529, filed July 26, 1984. In general, however, such features as specific combinations, degrees and sequences of strain hardening _and annealing are generally used for controlling the ductility and tensile properties of the final product. Setzer et al., referenced above, demonstrates several of these combinations, ranging from those ending with a fully hardened product (maximum cold work) to those ending with a fully strain-free (annealed) product. The use of a partial anneal as the final step to leave the desired amount of cold work remaining in the product is disclosed by Singleton, U.S. Patent No. 3 963 454 (June 15, 1976) at column 4, lines 34-58.

    [0010] It has now been discovered that the introduction of vanadium as an alloying element enhances the corrosion resistance of aluminum and aluminum alloys. In particular, brazing sheets containing such alloys as core alloys are unusually resistant to corrosion even after vacuum brazing. Corrosion-resistant AI alloys which contain vanadium are disclosed in GB-A 939 417. One such alloy (Ex. 1) contains 0.1% V (in addition to significant amounts of Cu, Mn, Zr and Ti) and shows improved corrosion-resistance after hot-rolling, annealing and cold-working, i.e. cold-rolling with a 10% reduction. Such alloys differ widely from the core allyos used in putting the present invention into effect, however, especially by reason of the high Cu content of 6.5% and other compositional differences. It has further been discovered that the corrosion resistance of products made from the alloys used in carrying out the invention is improved even more by the inclusion of a final cold work step to a reduction ranging from about 10% to about 20%.

    [0011] According to one aspect of this invention, a brazing material comprising an aluminum-based core alloy and a clading is characterised in that the aluminum-based core alloy is an alloy of the Aluminum Association 1XXX, 3XXX and 5XXX series, which also contains added vanadium as an alloying element in an amount in the range from 0.02% to 0.4% by weight of the core alloy, and that the cladding is an aluminum-base razing alloy.

    [0012] The invention also provides an aluminum sheet product formed by rolling an aluminum-base alloy to form a sheet, annealing the sheet to a substantially strain-free state and cold working the annealed sheet, characterised in that the aluminum-base alloy is an alloy of the Aluminum Association 1XXX, 3XXX and 5XXX series, which also contains added vanadium as an alloying element in an amount in the range from 0.02% to 0.4% by weight of the aluminum-base alloy, and that the cold working is carried out so as to effect a reduction of the sheet product in the range from 10% to 20%, together with the corresponding method.

    [0013] The amount of vanadium in the core alloy preferably is in the range from 0.05% to 0.3% by weight, as in most applications this provides the best results.

    [0014] The remainder of the alloy may vary widely in composition, although those alloys containing silicon, manganese, magnesium or combinations of these as the primary alloying elements, i.e., the components present in the highest concentrations other than the aluminum itself, are preferred. The concentrations of these elements may vary widely, but typically range from about 0.2% to 2.0% by weight. Preferred examples of core alloys, from the 1XXX, 3XXX or 5XXX series of Aluminum Association designated alloys, are the 1100, 3003, 3005, 3105 and 5005 alloys.

    [0015] In embodiments where the alloy is clad for brazing, the cladding alloy (also referred to herein as a "brazing alloy") may be any aluminum alloy capable of flow under brazing conditions to form fillets at the contact points sufficient to produce a sturdy bond. Such alloys will generally contain silicon as the primary alloying element, preferably at a concentration ranging from about 5% to about 15% by weight. Exam- pies of such alloys are those of the 4XXX series, e.g., 4004, 4043, 4045, 4047, 4104 and 4343.

    [0016] Brazing sheets of particular interest are those having a hardness ranging from fully annealed to about three-quarters hard. For example, air-conditioning evaporators require fully annealed metal, whereas for radiators one-quarter to three-quarters hard is preferred. As known to those skilled in the art, full hard is recognized in the industry as being equivalent to the hardness of a product which has been cold worked to a 75% reduction. In more preferred embodiments of the invention, the final brazing sheet is approximately one-half hard, i.e., ASTM temper designation H14.

    [0017] As mentioned above, preferred embodiments within the scope of the invention are those where the processing includes rolling the alloy or composite to form a sheet product, annealing the sheet product to a strain-free state, and finally cold working the annealed product to a reduction of about 10% to about 20%. The rolling step may include a number of substeps, including a hot working to bond the cladding to the core, a scalping or etching to remove the oxide formed on the surface during the hot working, and a cold working to bring the gauge down to a value somewhat higher than the desired ultimate value, so that the full anneal and final cold working will produce both the hardness and gauge sought.

    [0018] The cold working and annealing steps may be done according to conventional techniques well known to those skilled in the art. The annealing is generally done at a temperature of from about 500°F to about 850°F (260°C to 427°C), for a period of time ranging from about 0.5 hours to about 5 hours, preferably from about 600°F to about 700OF (316°C to 371 °C) for about 1 to 3 hours.

    [0019] For embodiments involving composite sheets, the cladding layer generally forms from about 0.1 percent to about 20 percent, preferably from about 1.0 percent to about 15 percent, of the thickness of the entire composite, and is present on one or both sides of the core, depending on the intended use of the brazing sheet. The bonding of the cladding to the core is typically achieved by conventional hot rolling techniques at temperatures ranging from about 450°F to about 1,000°F (230°C to 540°C). The cladding may be preceded by homogenization of the core typically at a temperature within the approximate range of from 800°F to 1150°F (427°C to 621 °C), although in some alloys and procedures corrosion resistance will be improved by omitting the homogenization step.

    [0020] Cold working is generally done by rolling, stretching or forming at ambient temperature. In general, the initial cold work step (prior to the full anneal) is done to a reduction of at least about 50%, preferably at least about 80%.

    [0021] Products prepared by the process of the present invention may be vacuum brazed according to conventional techniques. These usually involve a pressure of 10-2 torr or less, preferably between about 10-4 and about 10-6 torr, and a temperature ranging from about 1,000°F to about 1,200°F (540-650°C), preferably from about 1060°F to about 1125°F (571 °C to 607°C).

    [0022] The following examples are offered for purposes of illustration only, and are intended neither to define nor limit the invention in any manner.

    EXAMPLE 1


    BASELINE TESTS



    [0023] This example sets forth standards against which the product and process of the present invention may be compared. A variety of alloys, clad and unclad and of various tempers, none of which contain vanadium, were subjected to a standard corrosion test. The same test is used in the remaining examples in this specification.

    [0024] For the baseline test, pieces of sheet product ranging in thickness from 0.013 inch (0.03 cm) to 0.038 inch (0.10 cm) were cut into coupons measuring 2x3 inches (5.1 x 7.6 cm). Each coupon was masked on one side with electroplater's tape. The other side was intermittently exposed to an atomized corrosion solution (42 g/liter synthetic sea salt, 10 ml/liter acetic acid, balance water) in a 98% humid atmosphere for variable periods of time at a temperature of 120°F (49°C) according to ASTM Procedure No. G43. The coupons were then rinsed in cold water and cleaned in a solution of chromic and phosphoric acids (ASTM Solution No. G1) at 180°F (82°C), and baked for at least thirty minutes at 250°F (121°C) to remove retained water. Each coupon was then pressurized with air at 20 psig (13.8 newtons/cm2) under water and the number of perforations which resulted was determined by counting the streams of bubbles. The number of perforations per piece was recorded as a function of the number of hours in the corrosion solution.

    [0025] The results are shown in Table 1.1 where each entry represents a single coupon. In some cases two coupons were tested under identical conditions and the results for each are shown separated by a comma. The plus sign indicates that the actual number was above the number shown.



    [0026] The alloys used in the tests shown in Table 1.1 had the compositions shown in Table 1.2.



    [0027] A second group of coupons, clad on one side, total thickness 0.015 in (0.038 cm) and measuring 2-3/16 x 4-3/4 inches (5.6 x 12.1 cm) was brazed while suspended vertically in a three-chamber vacuum brazing furnace at a pressure of 1x10-5 torr and a temperature gradually increasing to 1100°F ±5 (593°C) in twelve minutes and held at that level for two minutes. The coupons were then further cut into 2-inch (5.1- cm) squares and the nonclad side masked. The corrosion test produced the results shown in Table 1.3.


    EXAMPLE 2


    ALUMINUM - VANADIUM ALLOY TESTS



    [0028] A composite (brazing sheet) was formed from the following materials:



    [0029] The composite was hot rolled to 0.0206 inch (0.052 cm), annealed at 650°F (360,C) for 25 minutes, then cold worked to 0.0187 inch (0.047 cm, a 9.2% reduction). Pieces of the sheet were subjected to a vacuum brazing cycle as in Example 1, cut to coupons 2.5 inches (6.4 cm) square, cooled to room temperature, masked on the unclad side, and corrosion tested as in Example 1.

    [0030] No leaks were detected on coupons exposed for 96 and 120 hours. Facial blisters occurred on coupons exposed for 240 hours, still without leaks.

    EXAMPLE 3


    ALUMINUM-VANADIUM ALLOY TESTS



    [0031] This example demonstrates the effects of final cold working on corrosion susceptibility. Two composites were prepared as follows:



    [0032] For each core, both a homogenized and an as-cast ingot were prepared. All were then scalped and clad 10% on one side to form the composites.

    [0033] The composites were hot rolled to 0.140 inch (0.36 cm) thickness, then cold rolled to 0.018 inch (0.046 cm). Each sheet was then cut into several portions. One portion was annealed by heating to 680°F (360°C) for two hours, then cold rolled to 0.0125 inch (0.032 cm) thickness (30% reduction). Other portions were cold rolled to an intermediate thickness, annealed at 680°F for two hours, then cold rolled to 0.0125 inch such that the cold reductions after annealing approximated 20%, 15%, 10% and 5% among the various portions.

    [0034] The samples were subjected to a vacuum brazing cycle as in Example 1 (the temperature this time gradually rising to 1115°F (602°C) over 33 minutes), cut into coupons 2 inches (5.1 cm) square, and cooled to room temperature. Two pieces of the 5% cold reduced portions were left unbrazed.

    [0035] For the corrosion test, electroplater's tape was applied to the backside of each coupon, leaving the clad size exposed. Of the unbrazed coupons, one out of each pair was taped on the core side, and the other on the clad side. The corrosion test described in Example 1 was then run. The results are listed in Tables 3.2 and 3.3, which include observations relating to both surface blisters and leaks.





    [0036] Comparing the figures in these tables with those in Tables 1.1 and 1.3, one notices a sharp reduction in the number of leaks (perforations) despite an increase in the amount of time in the corrosion test, all due to the presence of vanadium in the core alloy. (The "Blisters/Leaks" figures represent observations taken at the end of the test term.) One also notices an increase in the number of hours before the first blister appears for samples which were given a final cold reduction with the range of approximately 10% to 20%. Two unexpected improvements have thus been demonstrated.

    [0037] The foregoing description is offered primarily for illustrative purposes. It will be readily apparent to those skilled in the art that the particular materials and procedures described herein may be further varied or modified in numerous ways without departing from the spirit and scope of the invention as set forth in the following claims.


    Claims

    1. A brazing material comprising an aluminum-based core alloy and a cladding, characterised in that the aluminum-based core alloy is an alloy of the Aluminum Association 1XXX, 3XXX and 5XXX series, which also contains added vanadium as an alloying element in an amount in the range from 0.02% to 0.4% by weight of the core alloy, and that the cladding is an aluminum-base brazing alloy.
     
    2. A brazing material in accordance with claim 1, in which the vanadium comprises 0.05% to 0.3% by weight.
     
    3. A brazing material in accordance with claim 1 or 2, in which the core alloy further comprises at least one of silicon, magnesium and manganese.
     
    4. A brazing material in accordance with claim 3, in which the core alloy further comprises magnesium and manganese or both, as primary alloying elements.
     
    5. A brazing material in accordance with any preceding claim, in which the brazing alloy is an alloy of the Aluminum Association 4XXX series.
     
    6. A brazing material in accordance with any preceding claim, in which the brazing alloy contains silicon as an alloying element.
     
    7. A brazing material in accordance with claim 6, in which the brazing alloy contains from 5% to 15% of silicon by weight.
     
    8. An aluminum sheet product formed by rolling an aluminum-base alloy to form a sheet, annealing the sheet to a substantially strain-free state and cold working the annealed sheet, characterised in that the aluminum-base alloy is an alloy of the Aluminum Association 1 XXX, 3XXX and 5XXX series, which also contains added vanadium as an alloying element in an amount in the range from 0.02% to 0.4% by weight of the aluminum-base alloy, and that the cold working is carried out so as to effect a reduction of the sheet product in the range from 10% to 20%.
     
    9. A brazing material formed by cladding an aluminum-base core alloy with a brazing alloy, rolling the resultant clad product to form a sheet and annealing the sheet to a substantially strain-free state, characterised in that the core alloy contains vanadium as an alloying element, that the brazing alloy is aluminum-based and that the annealed sheet product is cold worked so as to effect a reduction in the range from 10% to 20%.
     
    10. A brazing material in accordance with claim 9, in which the vanadium comprises from 0.02% to 0.4% by weight of the core alloy.
     
    11. A brazing material in accordance with claim 9 or 10, in which the aluminum-base brazing alloy contains from 5% to 15% by weight of silicon.
     
    12. A method of producing an aluminum sheet product, which comprises rolling an aluminum-base alloy to form a sheet, annealing the sheet to a substantially strain-free state and cold working the annealed sheet, characterised in that the aluminum-base alloy is an alloy of the Aluminum Association 1XXX, 3XXX and 5XXX series, which also contains added vanadium as an alloying element in an amount in the range from 0.02% to 0.4% by weight of the aluminum-base alloy, and that the cold working is carried out so as to effect a reduction of the sheet product in the range from 10% to 20%.
     
    13. A method in accordance with claim 12, in which the vanadium comprises from 0.05% to 0.3% by weight of the aluminum-base alloy.
     
    14. A method in accordance with claim 12 or 13, in which the aluminum-base alloy further contains either or both of magnesium and manganese as primary alloying elements.
     
    15. A method of producing a brazing material, which comprises cladding an aluminum-base core alloy with a brazing alloy, rolling the resultant clad product to form a sheet and annealing the sheet to a substantially strain-free state, characterised in that the core alloy is an alloy of the Aluminum Association 1XXX, 3XXX and 5XXX series, which also contains added vanadium as an alloying element in an amount in the range from 0.02% to 0.4% by weight of the aluminum-base core alloy, and that the annealed sheet is cold worked so as to effect a reduction in the range from 10% to 20%.
     
    16. A method in accordance with claim 15, in which the vanadium comprises from 0.05% to 0.3% by weight of the aluminum-base core alloy.
     
    17. A method in accordance with claim 15 or 16, in which the brazing alloy contains silicon as an alloying element.
     
    18. A method in accordance with claim 17, in which the brazing alloy contains from 5% to 15% of silicon by weight.
     
    19. A method in accordance with any of claims 15 to 18, in which the core alloy further contains either or both of magnesium and manganese as primary alloying elements.
     


    Ansprüche

    1. Lötwerkstoff, bestehend aus einer Aluminiumkernlegierung und einer Plattierung, dadurch gekennzeichnet, daß die Aluminiumkernlegierung eine Legierung der Serien 1XXX, 3XXX und 5XXX der Aluminum Association ist, die als Legierungsbestandteil ebenfalls Vanadium enthält, und zwar mit einem Anteil von 0,02 bis 0,4 Gew.-% der Kernlegierung und daß die Plattierung eine Lötlegierung auf der Basis von Aluminium ist.
     
    2. Lötwerkstoff nach Anspruch 1, dadurch gekennzeichnet, daß der Vanadiumanteil 0,05 bis 0,3 Gew.- % beträgt.
     
    3. Lötwerkstoff nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß die Kernlegierung weiterhin wenigstens eines der Elemente Silicium, Magnesium und Mangan umfaßt.
     
    4. Lötwerkstoff nach Anspruch 3, dadurch gekennzeichnet, daß die Kernlegierung weiterhin Magnesium, Mangan oder beide Elemente als primäre Legierungsbestandteile aufweist.
     
    5. Lötwerkstoff nach einem der vorangegangenen Ansprüche, dadurch gekennzeichnet, daß die Lötlegierung eine Legierung der Serien 4XXX der Aluminum Association ist.
     
    6. Lötwerkstoff nach einem der vorangegangenen Ansprüche, dadurch gekennzeichnet, daß die Lötlegierung Silicium als Legierungsbestandteil aufweist.
     
    7. Lötwerkstoff nach Anspruch 6, dadurch gekennzeichnet, daß die Lötlegierung 5 des 15 Gew.-% Silicium aufweist.
     
    8. Aluminiumblecherzeugnis, welches durch Walzen einer Aluminiumlegierung zwecks Herstellung eines Bleches, Spannungsfreiglühen des Bleches bis zur Erreichung eines im wesentlichen spannungsfreien Zustandes und Kaltverformung des spannungsfrei geglühten Bleches hergestellt ist, dadurch gekennzeichnet, daß die Aluminiumlegierung eine Legierung der Serien 1XXX, 3XXX und 5XXX der Aluminum Association ist, die als Legierungsbestandteil ebenfalls Vanadium enthält, und zwar mit einem Anteil von 0,02 bis 0,4 Gew.-% der Aluminiumlegierung und daß die Kaltverformung dahingehend ausgelegt ist, daß sich eine Blechdickenabnahme in einem Bereich von 10 bis 20% ergibt.
     
    9. Lötwerkstoff, welcher durch Plattieren einer Aluminiumlegierung mit einer Lötlegierung, Walzen des plattierten Erzeugnisses zwecks Herstellung eines Bleches und Spannungsfreiglühen des Bleches bis zur Erreichung eines im wesentlichen spannungsfreien Zustands hergestellt ist, dadurch gekennzeichnet, daß die Kernlegierung als Legierungsbestandteil Vanadium enthält, daß die Lötlegierung eine Legierung auf der Basis von Aluminium ist und daß das spannungsfrei geglühte Blecherzeugnis kaltverformt ist, und zwar dahingehend, daß sich eine Dickenabnahme von 10 bis 20% ergibt.
     
    10. Lötwerkstoff nach Anspruch 9, dadurch gekennzeichnet, daß der Vanadiumanteil 0,02 bis 0,4 Gew.-% der Kernlegierung beträgt.
     
    11. Lötwerkstoff nach Anspruch 9 oder 10, dadurch gekennzeichnet, daß die Lötlegierung auf der Basis von Aluminium einen Anteil von 5 bis 15 Gew.-% Silicium enthält.
     
    12. Verfahren zur Herstellung eines Aluminiumblecherzeugnisses, bei welchem eine Legierung auf der Basis von Aluminium zwecks Herstellung eines Bleches gewalzt wird, das Blech bis zum Erreichen eines im wesentlichen spannungsfreien Zustands spannungsfrei geglüht wird und das spannungsfrei geglühte Blech kaltverformt wird, dadurch gekennzeichnet, daß die Legierung auf der Basis von Aluminium eine Legierung der Serien 1XXX, 3XXX und 5XXX der Aluminum Association ist, die als Legierungsbestandteil ebenfalls Vanadium enthält, und zwar mit einem Anteil von 0,02 bis 0,4 Gew.-% der genannten Aluminiumlegierung und daß die Kaltverformung dahingehend ausgelegt ist, daß sich eine Blechdickenabnahme in einem Bereich von 10 bis 20% ergibt.
     
    13. Verfahren nach Anspruch 12, dadurch gekennzeichnet, daß der Vanadiumanteil 0,05 bis 0,3 Gew.- % der genannten Aluminiumlegierung beträgt.
     
    14. Verfahren nach Anspruch 12 oder 13, dadurch gekennzeichnet, daß die genannte Aluminiumlegierung weiterhin Magnesium, Mangan oder beide Elemente als primäre Legierungsbestandteile aufweist.
     
    15. Verfahren zur Herstellung eines Lötwerkstoffs, wobei eine Aluminiumkernlegierung mit einer Lötlegierung plattiert wird, das plattierte Erzeugnis zwecks Herstellung eines Bleches gewalzt wird und das Blech bis zur Erreichung eines im wesentlichen spannungsfreien Zustands spannungsfrei geglüht wird, dadurch gekennzeichnet, daß die Kernlegierung eine Legierung der Serien 1XXX, 3XXX, 5XXX der Aluminum Association ist, welche als Legierungsbestandteil ebenfalls Vanadium enthält, und zwar mit einem Anteil von 0,02 bis 0,4 Gew.-% der Aluminiumkernlegierung und daß das spannungsfrei geglühte Blech kaltverformt wird, und zwar dahingehend, daß sich eine Bleckdickenabnahme von 10 bis 20% ergibt.
     
    16. Verfahren nach Anspruch 15, dadurch gekennzeichnet, daß der Vanadiumanteil 0,05 bis 0,3 Gew.- % der Aluminiumkernlegierung beträgt.
     
    17. Verfahren nach Anspruch 15 oder 16, dadurch gekennzeichnet, daß die Lötlegierung als Legierungselement Silicium enthält.
     
    18. Verfahren nach Anspruch 17, dadurch gekennzeichnet, daß die Lötlegierung Silicium mit einem Anteil von 5 bis 15 Gew.-% enthält.
     
    19. Verfahren nach einem der Ansprüche 15 bis 18, dadurch gekennzeichnet, daß die Kernlegierung weiterhin Magnesium, Mangan oder beide Elemente als primäre Legierungsbestandteile enthält.
     


    Revendications

    1. Matière pour brasage comprenant un alliage d'aluminium de base et un revêtement, caractérisée en ce que l'alliage d'aluminium de base est un alliage des séries 1XXX, 3XXX et 5XXX de l'Aluminum Association, qui contient également du vanadium ajouté comme élément d'alliage en une quantité de 0,02% à 0,4% en poids de l'alliage de base, et le revêtement est un alliage d'apport de brasage à base d'aluminium.
     
    2. Matière pour brasage suivant la revendication 1, dans laquelle le vanadium est présent en une quantité de 0,05% à 0,3% en poids.
     
    3. Matière pour brasage suivant la revendication 1 ou 2, dans laquelle l'alliage de base comprend en outre au moins un élément choisi entre le silicium, le magnésium et le manganèse.
     
    4. Matière pour brasage suivant la revendication 3, dans laquelle l'alliage de base comprend en outre du magnésium ou du manganèse, ou bien l'un et l'autre de ces éléments, comme éléments principaux d'alliage.
     
    5. Matière pour brasage suivant l'une quelconque des revendications précédentes, dans laquelle l'alliage d'apport de brasage est un alliage de la série 4XXX de l'Aluminum Association.
     
    6. Matière pour brasage suivant l'une quelconque des revendications précédentes, dans laquelle l'alliage d'apport de brasage contient du silicium comme élément d'alliage.
     
    7. Matière pour brasage suivant la revendication 6, dans laquelle l'alliage d'apport de brasage contient 5% à 15% en poids de silicium.
     
    8. Produit du type feuille d'aluminium formé par laminage d'un alliage à base d'aluminium pour former une feuille, recuit de la feuille à un état pratiquement dépourvu de contraintes et travail à froid de la feuille ayant subi un recuit, caractérisé en ce que l'alliage à base d'alminium est un alliage des séries 1XXX, 3XXX et 5XXX de l'Aluminum Association, qui contient également du vanadium ajouté comme élément d'alliage en une quantité de 0,02% à 0,4% en poids de l'alliage à base d'aluminium, et le travail à froid est effectué de manière à parvenir à une réduction de 10% à 20% du produit sous forme de feuille.
     
    9. Matière pour brasage formée en revêtant un alliage d'aluminium de base avec un alliage d'apport de brasage, en laminant le produit revêtu résultant pour former une feuille et en soumettant la feuille à un recuit à un état pratiquement dépourvu de contraintes, caractérisée en ce que l'alliage de base contient du vanadium comme élément d'alliage, l'alliage d'apport de brasage est à base d'aluminium et le produit sous forme de feuille ayant subi un recuit est soumis à un travail à froid de manière à parvenir à une réduction de 10% à 20%.
     
    10. Matière pour brasage suivant la revendication 9, dans laquelle le vanadium est présent en une quantité de 0,02% à 0,4% en poids de l'alliage de base.
     
    11. Matière pour brasage suivant la revendication 9 ou 10, dans laquelle l'alliage d'apport de brasage à base d'aluminium contient 5% à 15% en poids de silicium.
     
    12. Procédé de production d'une feuille d'aluminium, qui consiste à laminer un alliage à base d'aluminium pour former une feuille, à soumettre la feuille à un recuit à un état pratiquement dépourvu de contraintes et à soumettre la feuille ayant subi un recuit à un travail à froid, caractérisé en ce que l'alliage à base d'aluminium est un alliage des séries 1XXX, 3XXX et 5XXX de l'Aluminum Association, qui contient également du vanadium ajouté comme élément d'alliage en une quantité de 0,02% à 0,4% en poids de l'alliage à base d'aluminium, et le travail à froid est effectué de manière à parvenir à une réduction de 10 à 20% du produit sous forme de feuille.
     
    13. Procédé suivant la revendication 12, dans lequel le vanadium est présent en une quantité de 0,05% . à 0,3% en poids de l'alliage à base d'aluminium.
     
    14. Procédé suivant la revendication 12 ou 13, dans lequel l'alliage à base d'aluminium contient en outre du magnésium ou du manganèse ou bien l'un et l'autre de ces éléments, comme éléments principaux d'alliage.
     
    15. Procédé de production d'une matière pour brasage, qui consiste à revêtir un alliage d'aluminium de base avec un alliage d'apport de brasage, à laminer le produit revêtu résultant pour former une feuille et à soumettre la feuille à un recuit à un état pratiquement dépourvu de contraintes, caractérisé en ce que l'alliage de base est un alliage des séries 1XXX, 3XXX et 5XXX de l'Aluminum Association, qui contient également du vanadium ajouté comme élément d'alliage, en une quantité de 0,02% à 0,4% en poids de l'alliage d'aluminium de base, et la feuille ayant subi un recuit est soumise à un travail à froid de manière de parvenir à une réduction de 10% à 20%.
     
    16. Procédé suivant la revendication 15, dans lequel le vanadium est présent en une quantité de 0,05% à 0,3% en poids de l'alliage d'aluminium de base.
     
    17. Procédé suivant la revendication 15 ou 16, dans lequel l'alliage d'apport de brasage contient du silicium comme élément d'alliage.
     
    18. Procédé suivant la revendication 17, dans lequel l'alliage d'apport de brasage contient 5% à 15% en poids de silicium.
     
    19. Procédé suivant l'une quelconque des revendications 15 à 18, dans lequel l'alliage de base contient en outre du magnésium ou du manganèse, ou bien l'un et l'autre de ces éléments, comme éléments principaux d'alliage.