DE10196888B4 - Composite metal plate - Google Patents

Abstract

rigidity Composite metal plate containing at least two parallel metal sheets and / or -grobbleche, which at the tips and hollows of a Aluminum stiffening corrugated sheet are mounted between the parallel Heavy plates and / or sheets is arranged, characterized that the aluminum stiffening corrugated sheet is made of an aluminum brazing sheet product that has a core sheet (1) made of an aluminum alloy, that on at least one side and preferably on both sides of the Core sheet with an aluminum alloy clad layer (2) plated wherein the aluminum alloy cladding layer is made of an aluminum alloy is prepared, the silicon in an amount in the range of 2 to 18 wt .-%, preferably 5 to 14%, and having a nickel Layer (3) on the outer surface of Aluminum alloy clad.

Description

The The invention relates to a rigid composite metal plate with at least two parallel Metallgrobblechen and / or sheets, which at one Aluminum stiffening corrugated sheet fastened between the arranged parallel metal heavy plates and / or sheets, and a composite panel having at least two parallel metal heavy plates and / or sheets attached to an aluminum stiffening corrugated sheet a honeycomb structure are attached. The invention further relates a process for their preparation.

Composite metal plates having an internal honeycomb structure are usually produced by means of bonding, as disclosed, for example, in US Pat. No. 6,054,200 A. Composite metal plates with a corrugated sheet inside, in which the peaks and troughs are connected to the parallel metal plates, are usually produced by gluing or by welding techniques such as the laser welding techniques described, for example, in international application WO-00/26020 A1 and the GB 2 182 703 A are disclosed. The stiffness of the composite metal plate is largely due to the construction of the corrugated sheet or honeycomb structure.

Composite metal plates be used on load-bearing structures such as the ground or cargo decks a ship, the instrument board, the floor or wall panels an aircraft or land transport vehicle, e.g. a lorry or a car, for Architectural plates, for energy absorption or construction purposes from interior or exterior walls of a building used. There is a need for a solid metal composite panel construction, preferably a Leichmetallplatte, which also easy to manufacture is.

The EP 0 437 626 B1 discloses a solderable composite structure of steel corrugated sheets which are brazed together with a nickel-based braze to form a honeycomb-shaped structure.

A Object of the present invention is a composite metal plate provide that is easy and reliable to manufacture.

A Another object of the present invention is to provide a composite metal plate to be provided by means of brazing can be produced.

A Another object of the present invention is to provide a composite metal plate to provide, in which the parallel metal heavy plates and / or sheets from each other and / or from the aluminum stiffening sheet can be different.

A Another object of the present invention is to provide a composite metal plate to provide with an aluminum stiffening plate, both as Corrugated metal can also be used as a honeycomb-like structure.

To In one aspect of the invention, a composite metal plate is provided, which is set forth in claim 1.

To Another aspect of the invention is a composite metal plate provided as set forth in claim 2.

By the invention, a lightweight full metal composite plate can be provided, which is very rigid and can be used for various load-bearing structures. The invention may provide a composite metal plate which can be bonded or secured in a simple and reliable manner by means of a brazing operation, especially under controlled atmosphere brazing ("CAB") conditions in the absence of a brazing flux material such as the well-known Nocolok brazing flux material (US Pat. For example, it has been found that the aluminum brazing sheet product used can be formed into a corrugated sheet of various shapes and also into a honeycomb shape by suitable rolling means Suitable corrugated sheets have, for example, the shape of flat peaks and troughs, a dovetailed shape or curved peaks and troughs For example, a suitable honeycomb structure may be formed of two or more stiffening corrugated sheets each having flat peaks and troughs, and the tip of one sheet being attached to the trough of the other corrugated sheet brazed. The rigid honeycomb structure is formed in the same brazing operation in which the honeycomb structure is brazed to the parallel metal heavy plates or sheets. Moreover, the use of the present brazing sheet product for producing composite metal plates allows a honeycomb core having different numbers of honeycomb sections of different density; this because of variations in densities or other cell sizes.

at an embodiment the composite metal plate according to the invention is the aluminum stiffening corrugated sheet in the form of a turbulence generator plate, creating special rigid Metal composite panels can be designed and manufactured. Turbulence generator plate is a specialist for the production of heat exchangers known expression.

at an embodiment The composite metal plate according to the invention is the aluminum stiffening corrugated metal sheet a shaped sheet with several cup-like cavities, the are aligned substantially in parallel rows, and wherein in alternating parallel rows the openings of the cup-like cavities opposite Facing directions. The tip surfaces of the cup-like cavities form the tips or, alternatively, the wells of the stiffening corrugated sheet, and the top surfaces are by brazing connected to the parallel metal heavy plates or sheets. The top surfaces can be flattened to the contact surface with the parallel Metallgrobblechen or sheets to increase and thereby increase the strength of the joint after brazing. The cup-like cavities can have different shapes, that is circular, cylindrical, spherical or be conically shaped. A stiffening corrugated sheet of this type allows the Design and manufacture of composite metal plates with improved rigidity in several directions. Stiffening corrugated sheets with such Structure are known per se in the art and in particular used as heat shields in cars and trucks; in these known Applications is the sheet material only from an aluminum alloy and not made of brazing sheet, and in particular not from a brazing sheet containing a core sheet comprising a plurality of metal layers of different composition.

at an embodiment the aluminum brazing sheet product Further, the nickel-containing layer has bismuth in a range up to 5% by weight.

According to the invention was surprising found out that the Nickel layer do not contain lead as a mandatory alloying addition must, um a good brazeability to reach. Surprisingly found out that achieve equal or even better results when the Nickel layer bismuth is added, so that the Nickel layer can be kept substantially lead-free, and this at the same time in the plating bath, for the deposition This Ni-Bi layer is used. This is of particular importance since the use of lead for making brazed components and in different market areas is undesirable and in the near Future envisaged will that products banned or containing one or more intermediate processing steps made with lead or lead based components become.

at this aluminum brazing sheet product has the layer containing nickel or nickel bismuth preferred a thickness up to 2.0 μm, preferably up to 1.0 μm and more preferably up to 0.5 μm. A coating thickness of more than 2.0 μm requires a longer treatment time for the Galvanizing and can cause a wrinkling of the molten filler while the subsequent brazing to lead. A preferred minimum thickness for this Ni-Bi containing layer is about 0.25 μm.

Also other techniques such as thermal spraying, chemical vapor deposition ("CVD") or physical Vapor deposition ("PVD") or other known Techniques for depositing metals or metal alloys a gas or vapor phase can be used.

at an embodiment of aluminum brazing sheet product For example, the aluminum clad layer is an aluminum alloy of the series AA4000, the Si in a range of 2 to 18 wt .-% and preferred 5 to 14%, and further at least Mg in a range of up to 8% by weight and preferably up to 5% and more preferably in one range from 0.05 to 2.5 wt .-%.

In one embodiment, the aluminum brazing sheet product of the invention is further characterized by a layer comprising zinc or tin as a bonding layer between the outer surface of the aluminum clad layer and the nickel-containing layer. By the zinc or tin-containing bonding layer, a very effective bond is formed between the aluminum alloy clad layer and the nickel-containing layer, which bonding during the subsequent deformation of the aluminum hard Brazing plate remains effective, for example, during roll forming to obtain a stiffening corrugated sheet. The coverage of the nickel layer no longer depends on the surface properties of the bare plating layer. The aluminum brazing sheet product is suitable for fluxless brazing under controlled atmosphere conditions. This part of the invention is based in part on the insight that to obtain a well bonded nickel layer on the Si-containing aluminum clad layer of the brazing sheet product, pretreatment of the aluminum clad layer is extremely important when fabricating complicated corrugated metal structures, so that the bond remains effective under severe deformation , Obviously, the prior art processes aimed to deposit nickel in distributed form mainly on the surface of the aluminum cladding layer, rather than attempting to achieve a uniform nickel-lead layer. In the present invention, the surface of the Si-containing aluminum plating layer is changed so that the nickel coverage is independent of the silicon particles on its surface. The nickel plating does not take place on the silicon particles but on the applied thin compound layer containing zinc or tin. Accordingly, since the nickel is applied to the entire surface of the aluminum alloy clad layer, the required reaction before brazing can be made easier as compared with the prior art method. The applied zinc or tin does not interfere at all during the brazing process and may contain a brazing assistance component. Because the nickel is deposited smoothly and uniformly on the surface, the use of lead to promote wetting during brazing may be reduced or avoided, or other elements such as bismuth may be used for this purpose. Another important advantage, due to the fact that the nickel is deposited smoothly and evenly on the surface, is that it can reduce the total amount of nickel that must be applied to achieve good fluxless brazing.

The applied thin Bonding layer comprising zinc or tin preferably has one Thickness of up to 0.5 μm, more preferably up to 0.3 μm (300 nm) and most preferably in the range of 0.01 to 0.15 μm (10-150 nm). In the best results obtained, a thickness of about 30 mm used. A coating thickness of more than 0.5 μm is required a longer one Treatment time, e.g. For displacement plating, and it can be assumed that this is no further advantage Improvement of liability offers.

at an embodiment is the aluminum brazing sheet characterized in that the Zinc or tin-containing bond coat by a direct zinc plating treatment or applied by a zincate treatment or a stannate treatment is. Very good results can be achieved with a dip zincate treatment or a Tauchstannatbehandlung, often as Called displacement coating becomes. Another advantage is that this treatment for Application in a continuous process operation is suitable.

Zinkatbehandlungen are from the prior art per se for applying layers known on aluminum. Stannate treatments are in the art known to deposit a layer on aluminum to facilitate soldering, the electrical conductivity and aluminum alloy pistons for internal combustion engines while to give the lubricating surface a lubricated surface.

The Applied zinc or tin layer can be a pure zinc or tin layer or mainly zinc or tin (e.g., at least 50% by weight). Smaller amounts of Contaminants or deliberately added elements may be present which will be discussed in detail below becomes. Contaminants are typically less than 10% before, usually less than 5% by weight in the zinc or tin layer. The zinc or tin layer may contain less than 1 other elements.

at an embodiment of aluminum brazing sheet product For example, the aluminum alloy cladding layer has a thickness in the range from 2 to 20% of the total thickness of the total brazing sheet product thickness. The typical Aluminum cladding layer thickness is in the range of 40 to 80 microns. The core sheet typically has a thickness in a range of up to 5 mm, more preferably in the range of 0.1 to 2.5 mm.

The Core sheet of aluminum brazing sheet product is preferably made of an aluminum alloy such as one of the aluminum alloys series AA3000, AA5000 and AA6000.

In another embodiment of the composite metal plate of the invention, the aluminum brazing sheet product comprises an aluminum alloy core sheet clad on at least one surface of the core sheet and preferably on both sides with an aluminum cladding layer made of an aluminum alloy (typically an AA4000 series alloy ) having silicon in an amount in the range of 2 to 18% by weight of silicon and preferably 5 to 14%, having a nickel A layer on the outer surface of the aluminum alloy clad layer and a separately deposited metal layer on one side of the nickel-containing layer, wherein the separated metal layer comprises such a metal that the aluminum clad layer and all layers of the aluminum brazing sheet product outside together form a metal filler having a liquidus temperature in the range of 490 to 570 ° C and preferably in the range of 510 to 550 ° C has.

With this aluminum brazing sheet product according to the invention is a brazing sheet product provided, compared to conventional brazing temperatures, typically in the range of 575 to 600 ° C, with significantly lower Temperatures brazed can be while still a very strong and reliable bond is achieved. This brazing sheet can be used in vacuum brazing and fluxless brazing under controlled atmosphere conditions, but preferred become the fluxless CAB conditions applied. Such a brazing sheet product can on an industrial scale without the awkward Use of metal foils or sheets are produced, the themselves are difficult to produce. With this aluminum brazing sheet product it is also possible more unusual Brazing metals into a composite metal plate, for example aluminum sheets from alloys of the series AA5000 with Mg in a range of up to to be used at 6.0% by weight like, but not limited to, AA5052, AA5056, AA5083 and AA5059.

at an embodiment has on at least one side of the core sheet, the layer that has a metal, so that taken together the aluminum cladding layer and all layers outside a metal filler form with a reduced liquidus temperature, copper or a Copper-based alloy, and the layer is more preferable at least 60 wt .-% copper on. For example, suitable copper based alloys can be used Be brass or bronze.

The applied layer, the copper or a copper-based alloy preferably has a thickness of up to 10 microns, more preferably of up to 7 microns. The best results became a thickness used by about 4 microns.

you has found that in particular Copper the liquidus temperature of the resulting metal filler significantly reduced. However, you can additionally be applied more metal layers.

at an embodiment is the aluminum brazing sheet characterized in that the Layer comprising copper or a copper-based alloy, deposited by electroplating. However, too other techniques such as thermal spraying, plasma spraying, CVD, PVD or other known techniques for depositing metals or Metal alloys are used from a gas or vapor phase.

at an embodiment is the copper or a copper-based alloy having Layer by electroplating of copper or an alloy Copper base using an aqueous plating bath Deposited on a copper cyanide basis.

at an embodiment is the copper or a copper-based alloy having Layer by electroplating of copper or an alloy Copper base using an aqueous plating bath deposited on a copper phosphate basis. This aqueous plating bath has proved to be functional over a wide pH range, and it can be used on galvanizing lines on an industrial scale which use a high current density, which in turn quite a bit high line speeds possible become. It can be done using standard chemicals and readily available chemicals can be put together, and copper can in the plating bath slightly refilled become.

An embodiment of the aluminum brazing sheet product is characterized in that the aluminum cladding layer and all layers outside taken together have a composition having at least the following in wt%:
Si in the range of 5 to 10%, preferably 7 to 10%;
Cu in the range of 12 to 25%, preferably 12 to 18%;
Bi in the range up to 0.25%, preferably 0.02 to 0.25%;
Ni in the range of 0.05 to 4%, preferably 0.05 to 3.0%;
Zn in the range up to 20%, preferably up to 10%, more preferably up to 0.25%;
Sn in the range up to 5%;
Mg in the range up to 5%;
Rest aluminum and impurities.

One Typical impurity elements may be iron, in particular derived from the aluminum clad layer and tolerated up to 0.8% can be. Other alloying elements can be present and originate typically, but not exclusively, of the aluminum cladding layer. In this embodiment is a metal filler obtained having a liquidus temperature in the range of 510 to 550 ° C and the Production of composite metal plates at significantly lower temperatures compared to conventional brazing on an industrial scale for devices like heat exchangers allows being a more unconventional choice of aluminum alloys for the parallel Heavy plates or sheets for the composite metal plate possible is, namely those with low melting point ingredients.

at an advantageous embodiment is the aluminum brazing sheet characterized in that the Nickel-containing layer by galvanization of nickel as well Bismuth using an aqueous, lead-free bath is deposited, which is a nickel ion concentration in a range of 10 to 100 g / l and a bismuthine concentration in the range of 0.01 to 10 g / l, and more preferably by electroplating of nickel and bismuth using an aqueous, lead-free bath a nickel ion concentration in a range of 20 to 70 g / l and a bismuth concentration in the range of 0.02 to 5 g / l having.

at this aspect of the invention has surprisingly been found that the Nickel layer no lead as a mandatory alloying addition must have for a good brazeability to reach. Surprisingly it was found out that get the same or even better results if the Nickel layer bismuth is added so that the nickel layer substantially can be kept free of lead, and at the same time the plating bath, that for the deposition of this Ni-Bi layer is used. By using this watery, lead-free electroplating bath has overcome the need for lead additive, which is an essential achievement from an environmental point of view.

The nickel ion concentration in the aqueous bath may be added via the addition of nickel chloride, nickel fluoroborate, nickel sulfamate, nickel acetate or nickel sulfate. However, it is preferable to use the addition of nickel sulfate (NiSO ₄ ). If the level of nickel salt in the aqueous bath is too high, there is a risk of crystallization of the salt in the solution, which could damage a continuous process. At too low levels, the resulting bath becomes uneconomical because of too long plating times and low current density.

Bi-ions in the concentration set forth above can be added to the aqueous bath in a variety of ways. Theoretically, many bismuth compounds could be used for this. However, many bismuth compounds have been tried, and only a few seem to provide reliable and reproducible results. For example, the addition of bismuth acetate has been tried, but it has been found that this compound did not dissolve in the plating bath used, while the addition of lead acetate did not cause any problems with the solution of this compound. For example, the combination of a bath of nickel ions and bismuth ions and a tartrate having a pH in excess of 8 also resulted in the formation of undesirable Ni-containing sludge. This Ni-containing sludge did not dissolve upon heating, indicating inter alia that Ni is unstable in the presence of a tartrate in the pH range mentioned. Very good results have been achieved according to the invention when bi-ions have been added via the addition of one or more of the group consisting of the following: bismuth carbonate (Bi ₂ (CO ₃ ) ₃ ), Bismuth oxide (Bi ₂ O ₃ ), bismuth citrate (BiC ₆ H 5 O ₇ ) and bismuth chloride (BiCl ₃ ). By using bismuth carbonate or bismuth oxide in the presence of nickel, a suitable plating bath was obtained which is stable in a very wide pH range. At too high levels of bi-ion concentration in the aqueous bath, the resulting deposit will have an undesirably high Bi concentration. The Bi concentration in the resulting Ni-Bi layer on the brazing sheet product is preferably not more than 5% by weight, and more preferably not more than 3% by weight. At too low levels, the resulting bath becomes uneconomical due to too long plating times and low current density.

• – Nickelsulfat in einem Bereich von 45 bis 450 g/l und bevorzugt 90 bis 315 g/l,
• – Chlorid-Ionenkonzentration in einem Bereich von 1 bis 50 g/l und bevorzugt 1 bis 30 g/l,
• – Natriumcitrat in einem Bereich von 55 bis 180 g/l und bevorzugt 110 bis 150 g/l,
• – Natriumgluconat in einem Bereich von 2 bis 90 g/l und bevorzugt 5 bis 55 g/l,
• – Ammoniumsulfat in einem Bereich bis zu 270 g/l,
• – Wismutoxid in einem Bereich von 0,02 bis 22 g/l und bevorzugt 0,05 bis 11 g/l oder Wismutcarbonat in einem Bereich von 0,03 bis 29 g/l und bevorzugt 0,06 bis 14 g/l.

Galvanization baths proved to be particularly effective, using the following salts in grams per liter:

• Nickel sulfate in a range of 45 to 450 g / l and preferably 90 to 315 g / l,
• Chloride ion concentration in a range of 1 to 50 g / l and preferably 1 to 30 g / l,
• Sodium citrate in a range of 55 to 180 g / l and preferably 110 to 150 g / l,
• Sodium gluconate in a range from 2 to 90 g / l and preferably from 5 to 55 g / l,
• Ammonium sulfate in a range up to 270 g / l,
• Bismuth oxide in a range from 0.02 to 22 g / l and preferably from 0.05 to 11 g / l or bismuth carbonate in a range from 0.03 to 29 g / l and preferably from 0.06 to 14 g / l.

The Addition of an ion from the group consisting of chloride and fluoride, is required to induce anode corrosion.

The used according to the invention Galvanizing bath can be used in a wide pH range from 2.5 to 10 and preferably in the range of 4 to 8, without the properties of the bath and without loosening the aluminum cladding layer.

at an embodiment the composite metal plate is characterized in that one or a plurality of the parallel metal heavy plates or sheets of a metal are selected from the group consisting of the following consists of: aluminum, aluminum alloy, titanium, clad or coated titanium, bronze, brass, stainless steel, plated or coated stainless steel, low carbon steel, plated or coated low carbon steel, high strength steel and clad or coated high strength steel, nickel or nickel alloy. An example of a suitable stainless steel sheet or plate is a copper plated material. Suitable stainless steel grades are those with 0.01 to 0.35 wt .-% carbon and 11 to 27 wt .-% Cr according to the definition of steel numbers such as ferritic classes, e.g. ASTM 409, 410S, 430; martensitic classes, e.g. ASTM 420; Duplex classes e.g. ASTM 329, S1803; austenitic classes, e.g. ASTM 301, 304L, 321, 316L; warmth- and creep-resistant classes, e.g. ASTM 309S, 304H.

According to the invention was found out that the above aluminum brazing sheet product by means of brazing with the parallel heavy plates or plates of different metals can be connected, in particular in a brazing process in an inert atmosphere (CAB) in the absence of a brazing flux material. The parallel heavy plates or plates can be made of aluminum alloys be made as nonlimiting, from the alloys AA3000 series, but by brazing more unusual ones Aluminum alloys of the series AA5000 with magnesium as essential Alloy element in a range up to 6 wt .-%, and also aluminum alloys from the series AA6000. The composite metal plate can also be used in just one brazing are formed from different metal combinations, for example a parallel sheet metal plate or copper plate made of copper-plated stainless steel, and the other parallel metal sheet or plate low carbon steel by using the above Aluminiumhartlötblechprodukts produced.

To Another aspect of the invention is a method for Production of rigid composite metal plates provided as they set forth above. The procedure is characterized by the features of Claim 20 wherein the fluxless CAB operation is preferred.

The Invention will now be by way of non-limiting example with reference illustrated on the drawings; show in it:

1 a schematic longitudinal section showing the aluminum brazing sheet product used in the composite metal plate according to the invention;

2 a schematic longitudinal section showing the aluminum brazing sheet product used in the composite metal plate according to the invention;

3 a schematic cross section of a composite metal plate according to the invention;

4 a schematic excerpt cross section of in 3 shown composite metal plate;

5 a schematic cross section of a composite metal plate according to the invention;

6 a schematic cross section of a composite metal plate according to the invention; and

7 a schematic perspective view of a special form of aluminum stiffening corrugated sheet according to the invention.

1 schematically shows a brazing sheet product used in a composite metal plate according to the invention. The brazing sheet product has an aluminum core sheet 1 on, on both sides with an aluminum alloy cladding layer 2 is plated, a nickel or nickel bismuth-containing layer on the outer surface of the aluminum alloy cladding layer 2 and a zinc or tin-containing thin bonding layer 4 between the layers 2 and 3 , The composition and thickness of the various layers and their advantages have been set forth above.

2 also schematically shows a brazing sheet product used in a composite metal plate according to the invention. In this embodiment, the brazing sheet product of 1 used, wherein on the nickel or nickel bismuth layer having 3 another metal layer 5 which preferably comprises copper to reduce the liquidus temperature of the metal filler, that of the plating layer 1 and all layers are formed outside on one side of the aluminum core sheet. The further metal layer 5 can (as shown) on the nickel layer 3 be applied or under the nickel layer 3 (Not shown). The compositions of the various layers and their advantages have been set forth above.

3 Figure 3 is a schematic cross-section of a composite metal plate according to the invention, showing two parallel metal heavy plates or sheets 6 . 7 which are joined together by brazing the tips and troughs of an aluminum stiffening corrugated sheet. That by the in 1 or 2 aluminum brazing sheet formed aluminum corrugated sheet formed is V-shaped.

4 is a schematic excerpt cross section of in 3 shown composite metal plate, in which a parallel metal sheet or sheet metal 7 shown with the aluminum stiffening corrugated sheet 8th with a welding strip 9 which has been formed after heating a package of parallel metal heavy plates or sheets and the aluminum stiffening sheet to a high temperature, during heating of the aluminum alloy plating layer 2 and all metal layers 2 . 3 . 4 . 5 outside the aluminum cladding layer, in 1 and 2 a molten filler is formed to form a strong bond or joint between the separated parts.

5 shows a similar structure as 3 which is due to the aluminum brazing sheet product of 1 or 2 formed aluminum corrugated sheet 8th has flat peaks and hollows.

6 Figure 3 is a schematic cross-section of a composite metal plate according to the invention formed by three parallel metal heavy plates or sheets 6 . 7 . 10 formed with each other via the tips and hollows of the aluminum stiffening corrugated sheets 8th are connected. That by the aluminum brazing sheet product of 1 or 2 formed aluminum corrugated sheet is V-shaped. The orientation of the two different aluminum stiffening sheets is perpendicular to each other to improve the rigidity of the resulting composite metal sheet in different directions. It will be readily apparent to one skilled in the art that depending on the desired stiffness of the composite metal plate, any orientation angle between the various aluminum stiffening plates may be selected. The same applies to the shape of the aluminum stiffening sheet.

7 Figure 3 is a schematic perspective view of a particular form of aluminum stiffening corrugated sheet according to the invention, the stiffening sheet being a shaped sheet having a plurality of cup-like cavities 11 . 12 which are substantially aligned in parallel rows, and wherein in alternating parallel rows the openings of the cup-like cavities face opposite directions. The tip surfaces of the cup-like cavities form the tips or, alternatively, the wells of the stiffening corrugated sheet, and the tip surfaces are brazed to the parallel metal heavy plates or sheets. Like this in 7 As shown, the tip surfaces may be flattened to increase the area of contact with the parallel metal plates or sheets and thereby increase the strength of the joint after brazing. Depending on the required stiffness of the composite metal plate, the cup-like cavities may have different shapes, that is circular, cylindrical, spherical or conical shaped. A corrugated corrugated sheet of this type enables the design and manufacture of multi-directional composite metal plates with improved rigidity. The distance between two cup-like cavities aligned in the same row may depend on the application of the composite metal plate and is typically in the range of 10 to 30 mm. The depth of the cup-like cavities may also depend on the application and is typically in the range of up to 25 mm.

example

On a laboratory scale, tests were carried out on aluminum brazing sheet made of a core alloy AA3003 is plated on both sides with a AA4045 plating alloy and has a total thickness of 0.5 mm, the thickness of each plating being 10.9% of the total thickness. The composition of these alloys is given in Table I.

• – Reinigen durch Eintauchen für 180 s in ChemTec 30014 (Handelsname; ein handelsüblicher alkalischer (Ätz)entfetter) und Spülen;
• – alkalisches Ätzen für 20 s in ChemTec 30203 (Handelsname; ein handelsüblicher alkalischer Ätzreiniger) und Reinigen;
• – Entrußen für 4 s in einer acidischen Oxidationslösung, typischerweise 25 – 50 Vol.-% Salpetersäure, mit ChemTec 11093 (Handelsname; ein handelsüblicher Beizaktivator) bei Umgebungstemperatur, gefolgt von Spülen;
• – Zinkattauchen unter Verwendung von ChemTec 024202 für 12 s bei Zimmertemperatur, woraus sich eine Zinkschicht von etwa 30 Nanometer ergab, gefolgt von Spülen;
• – Nickelgalvanisieren und Spülen. Die Nickel aufweisende Schicht wurde unter Verwendung eines Nickelgalvanisierungsbades mit der in Tabelle 2 dargelegten Zusammensetzung und einem pH-Wert von 5,5 aufgebracht. Die Bi-Ionenkonzentration wurde dem Galvanisierungsbad durch Verwendung eines Bi-Ionenkonzentrats aus 160 g/l Natriumhydroxid, 300 g/l Natriumgluconat und 111 g/l Wismutoxid zugegeben. Das Wismutoxid hätte auch durch Wismutcarbonat ersetzt werden können. Die Galvanisierung einer Ni-Bi-Schicht wurde bei 57°C unter Ver wendung einer Stromdichte von 6 A/dm² und einer Galvanisierungszeit von 25 s durchgeführt. Etwa 10 g/m² Nickel und etwa 0,5 g/m² Wismut wurden abgeschieden, also die Summe der aufgebrachten Schichten an beiden Seiten des Hartlötblechprodukts. Der Wismutgehalt der abgeschiedenen Legierungsschicht kann leicht variiert werden, z.B. durch Senkung der Wismut-Konzentration in dem Galvanisierungsbad, so daß sich ein niedrigerer Bi-Gehalt ergibt.

The brazing sheet was treated by the following sequential process steps:

• - Clean by dipping for 180 s in ChemTec 30014 (trade name, a commercial alkaline (caustic) degreaser) and rinse;
• Alkaline etching for 20 sec in ChemTec 30203 (trade name, a commercial alkaline caustic cleaner) and cleaning;
• Gassing for 4 seconds in an acidic oxidation solution, typically 25-50% by volume nitric acid, with ChemTec 11093 (trade name, a commercial pickle activator) at ambient temperature, followed by rinsing;
• Zinc dipping using ChemTec 024202 for 12 seconds at room temperature resulting in a zinc layer of about 30 nanometers, followed by rinsing;
• - Nickel electroplating and rinsing. The nickel-containing layer was deposited using a nickel plating bath having the composition set forth in Table 2 and a pH of 5.5. The bi-ion concentration was added to the plating bath by using a bi-ion concentrate of 160 g / L sodium hydroxide, 300 g / L sodium gluconate and 111 g / L bismuth oxide. The bismuth oxide could also have been replaced by bismuth carbonate. The galvanization of a Ni-Bi layer was carried out at 57 ° C using a current density of 6 A / dm ² and a galvanization time of 25 s. About 10 g / m ² nickel and about 0.5 g / m ² bismuth were deposited, ie the sum of the applied layers on both sides of the brazing sheet product. The bismuth content of the deposited alloy layer can be easily varied, for example, by lowering the bismuth concentration in the plating bath to give a lower Bi content.

The Aluminiumhartlötblechprodukt was made using the Erichsen dome scoring test (5 mm) and the T-bend test. Then the liability with the values deficient, moderate or well rated. The adhesion of the resulting brazing sheet product was rated as good, making the aluminum brazing sheet product considerable Subjected to deformation operations such as typical roll forming operations could be to get the required stiffening corrugated sheet.

To In the adhesion test, the aluminum brazing sheet product became a corrugated iron with V-shaped tips and troughs curled, and the space between two peaks was about 20 mm, and the height the corrugated sheet was about 8.5 mm. The corrugated iron was between two parallel sheets of a material of the series AA3003 and also between two parallel sheets of copper - plated stainless steel Class 304L placed. All parallel sheets had dimensions of about 20 × 20 cm and a thickness of about 1 mm. During brazing was on the unsoldered Apply some pressure to assembly by placing a load of about 1 kg was applied to the upper parallel metal sheet. The assemblies were in a brazing oven set and under streaming Heated nitrogen, with heating from room temperature to 580 ° C, a residence time at 580 ° C for 1 minute, Cooling from 580 ° c at room temperature.

Both resulting composite metal plates had an excellent brazed bond between the parallel sheets and the aluminum brazing sheet product. Both metal plates were very rigid, further by choice the shape of the aluminum reinforcement corrugated sheet to be optimized can. This experiment demonstrates that by means of a single brazing operation using the aluminum brazing sheet product a rigid one Composite metal plate can be molded. In addition, there is no need to the brazing operation an additional Additive as a usual apply brazing flux material used; so are many awkward Processing steps and also the required removal of excess Hartlöflußmittelmaterial after the brazing operation avoided, what with complicated shaped Aluminiumaussteifungsblechen or composite metal plates with large dimensions difficult can be. To obtain excellent brazeability, the nickel layer must not obligatory lead to be added. Similar or even better Results can be obtained by using an addition of Bi to the Nickel containing layer obtained. Optionally, the aluminum plating layer also be added bismuth.

Table 1% by weight

Table 2

To the complete It will be understood by those skilled in the art that many changes and modifications can be made without departing from the spirit or scope of the invention described herein departing.

Claims (21)

A rigid composite metal plate having at least two parallel metal sheets and / or plates attached to the tips and troughs of an aluminum stiffening corrugated sheet interposed between the parallel plates and / or sheets, characterized in that the aluminum stiffening corrugated sheet is made of an aluminum brazing sheet product, that a nuclear sheet ( 1 aluminum alloy cladding on at least one side and preferably on both sides of the core sheet with an aluminum alloy cladding layer ( 2 ), wherein the aluminum alloy cladding layer is made of an aluminum alloy comprising silicon in an amount in the range of 2 to 18% by weight, preferably 5 to 14%, and a layer comprising nickel ( 3 ) on the outer surface of the aluminum alloy clad layer. A rigid composite metal plate having at least two parallel metal sheets and / or plates attached to an aluminum stiffening corrugated sheet having a honeycomb structure disposed between the parallel plates and / or sheets, characterized in that the aluminum stiffening corrugated sheet is made of an aluminum brazing sheet product a core sheet ( 1 ) of an aluminum alloy, which on at least one side and preferably on both sides of the core sheet with an aluminum alloy clad layer ( 2 ), wherein the aluminum alloy cladding layer is made of an aluminum alloy comprising silicon in an amount in the range of 2 to 18% by weight, preferably 5 to 14% by weight, and a layer comprising nickel ( 3 ) on the outer surface of the aluminum alloy clad layer. A composite metal plate according to claim 1, wherein the aluminum stiffening corrugated sheet in the form of a turbulence generator plate is present. A composite metal plate according to claim 1, wherein the aluminum stiffening corrugated sheet has a shaped sheet with several cup-like cavities is substantially aligned in parallel rows, and wherein in alternating parallel rows the openings of the cup-like cavities facing opposite directions. A composite metal plate according to any one of claims 1 to 4, wherein the nickel-containing layer ( 3 ) further comprises bismuth in a range of at most 5% by weight. A composite metal plate according to any one of claims 1 to 5, wherein the nickel-containing layer ( 3 ) is substantially lead free. A composite metal plate according to any one of claims 1 to 6, wherein the nickel-containing layer ( 3 ) has a thickness of not more than 2.0 microns, preferably not more than 1.0 microns. A composite metal plate according to any one of claims 1 to 7, wherein the nickel-containing layer ( 3 ) is applied by electroplating. A composite metal plate according to any one of claims 5 to 8, wherein the nickel-containing layer ( 3 ) is deposited by electroplating nickel and bismuth using an aqueous bath having a nickel ion concentration in a range of 10 to 100 g / l and a bismuth ion concentration in the range of 0.01 to 10 g / l. A composite metal plate according to any one of claims 1 to 7, wherein the nickel-containing layer ( 3 ) is applied by a PVD method or by thermal spraying. A composite metal plate according to any one of claims 1 to 10, wherein the aluminum clad layer ( 2 ) further comprises magnesium in a range up to 8%. A composite metal plate according to any one of claims 1 to 11, wherein a zinc or tin-containing layer ( 4 ) as a bonding layer between the outer surface of the aluminum clad layer ( 2 ) and the nickel-containing layer ( 3 ) is provided. A composite metal plate according to claim 12, wherein the bonding layer ( 4 ) has a thickness of not more than 1 micron, preferably not more than 0.5 micron. Composite metal plate according to one of claims 12 or 13, in which the zinc or tin-containing bonding layer ( 4 ) is applied by a zincate treatment or a stannate treatment. A composite metal plate according to any one of claims 1 to 14, wherein the aluminum stiffening corrugated sheet is made of an aluminum brazing sheet product comprising a core sheet ( 1 ) made of an aluminum alloy, which on at least one side and preferably on both sides of the core sheet ( 1 ) with an aluminum alloy clad layer ( 2 ), wherein the aluminum alloy cladding layer is made of an aluminum alloy comprising silicon in an amount in the range of 2 to 18% by weight, preferably 5 to 14%, and a layer comprising nickel ( 3 ) on the outer surface of the aluminum alloy cladding layer, and a separately deposited metal layer ( 5 ) on one side of the nickel-containing layer ( 3 ), and wherein the separate metal layer ( 5 ) has a metal, so that the aluminum clad layer ( 2 and all layers of the aluminum brazing sheet product taken together taken together form a metal filler having a liquidus temperature in the range of 490 to 570 ° C and preferably in the range of 510 to 550 ° C. A composite metal plate according to claim 15, wherein the layer ( 5 ) Copper or a copper-based alloy. A composite metal plate according to claim 16, wherein the layer ( 5 ) has at least 60 wt .-% copper. A composite metal plate according to any one of claims 15 to 17, wherein the layer ( 4 ) has a thickness of not more than 10 microns. Composite metal plate according to one of claims 1 to 18, in which one or more of the parallel metal heavy plates or sheets made of a metal that is from the group selected consisting of the following: aluminum, aluminum alloy, titanium, plated or coated titanium, bronze, brass, stainless Steel, clad or coated stainless steel, low carbon Steel, clad or coated low carbon steel, high strength Steel and clad or coated high strength steel, nickel or Nickel alloy. Composite metal plate according to one of claims 1 to 19, wherein the parallel plates and / or plates on the Aluminum stiffening plate fixed by brazing or connected are, and preferably under controlled by means of a brazing process the atmosphere in the absence of a brazing flux material. Method for producing a rigid composite metal plate, the following steps include: (a) parts of at least two parallel metal heavy plates and / or sheets and an aluminum stiffening corrugated sheet are provided, which from the Aluminiumhartlötblechprodukt after one of claims 1 to 8 is made; (b) the parts become one Assembled assembly that the aluminum stiffening plate between the parallel metal heavy plate and / or sheet is arranged; (C) the assembly is assembled into a rigid composite metal plate by the assembly under a vacuum or in an inert atmosphere in the absence a brazing flux material is heated at a high temperature of less than 600 ° C for a period of time, long enough to melt and distribute the molten filler is to make a joint between each of the parallel metal heavy plates and / or sheets and the aluminum stiffening corrugated sheet (D) cooling down the joined together Composite metal plate.