Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C21/00—Alloys based on aluminium
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
  • B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
  • B23K35/24—Selection of soldering or welding materials proper
  • B23K35/28—Selection of soldering or welding materials proper with the principal constituent melting at less than 950 degrees C
  • B23K35/286—Al as the principal constituent
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K1/00—Soldering, e.g. brazing, or unsoldering
  • B23K1/0008—Soldering, e.g. brazing, or unsoldering specially adapted for particular articles or work
  • B23K1/0012—Brazing heat exchangers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
  • B23K35/02—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
  • B23K35/02—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape
  • B23K35/0222—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape for use in soldering, brazing
  • B23K35/0233—Sheets, foils
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
  • B23K35/02—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape
  • B23K35/0222—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape for use in soldering, brazing
  • B23K35/0233—Sheets, foils
  • B23K35/0238—Sheets, foils layered
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B15/00—Layered products comprising a layer of metal
  • B32B15/01—Layered products comprising a layer of metal all layers being exclusively metallic
  • B32B15/016—Layered products comprising a layer of metal all layers being exclusively metallic all layers being formed of aluminium or aluminium alloys
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
  • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
  • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
  • C21D8/0226—Hot rolling
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
  • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
  • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
  • C21D8/0236—Cold rolling
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
  • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
  • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
  • C21D8/0273—Final recrystallisation annealing
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C21/00—Alloys based on aluminium
  • C22C21/02—Alloys based on aluminium with silicon as the next major constituent
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C21/00—Alloys based on aluminium
  • C22C21/02—Alloys based on aluminium with silicon as the next major constituent
  • C22C21/04—Modified aluminium-silicon alloys
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
  • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
  • C22F1/04—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
  • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
  • C22F1/04—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon
  • C22F1/043—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon of alloys with silicon as the next major constituent
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
  • C23C28/02—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings only including layers of metallic material
  • C23C28/021—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings only including layers of metallic material including at least one metal alloy layer
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F21/00—Constructions of heat-exchange apparatus characterised by the selection of particular materials
  • F28F21/08—Constructions of heat-exchange apparatus characterised by the selection of particular materials of metal
  • F28F21/089—Coatings, claddings or bonding layers made from metals or metal alloys
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K2101/00—Articles made by soldering, welding or cutting
  • B23K2101/04—Tubular or hollow articles
  • B23K2101/14—Heat exchangers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F21/00—Constructions of heat-exchange apparatus characterised by the selection of particular materials
  • F28F21/08—Constructions of heat-exchange apparatus characterised by the selection of particular materials of metal
  • F28F21/081—Heat exchange elements made from metals or metal alloys
  • F28F21/084—Heat exchange elements made from metals or metal alloys from aluminium or aluminium alloys

Definitions

• the invention relates to thin strips (of thickness generally between 0.05 to 3 mm, preferably 0.15 to 2.5 mm) of aluminum-manganese core alloy (3000 series according to the nomenclature of the Aluminum Association), optionally plated on one or both sides of a cover alloy, most often an aluminum-silicon brazing alloy (4000 series according to the Aluminum Association nomenclature) and / or an intermediate alloy, placed between the core and the possible brazing alloy, in aluminum-manganese alloy (3000 series according to the Aluminum Association nomenclature).
• These bands are intended in particular for the manufacture of elements, such as tubes, collectors and plates, of heat exchangers assembled by brazing. These exchangers are found in particular in engine cooling and air conditioning systems in automobile interiors.
• brazing aluminum alloys are described for example in the article by JC Kucza, A. Uhry and JC Goussain "The strong brazing of aluminum and its alloys", published in Soudage et Techniques Connexes, Nov.- Dec. 1991, pp. 18-29.
• the strips according to the invention can be used in brazing techniques with non-corrosive flux of NOCOLOK ® kind or CAB (controlled atmosphere brazing), or, alternatively, in brazing techniques without flux.
• the properties required for the aluminum alloy strips used for the manufacture of brazed exchangers are in particular good brazability, high mechanical strength after brazing, so as to use thicknesses as low as possible, formability sufficient for easy shaping of tubes, manifold fins and plates, before brazing, and good corrosion resistance.
• the alloy chosen is easy to cast and roll, and that the cost of manufacturing the strips is compatible with the requirements of the automotive industry.
• An alloy used is 3003 with the composition (% by weight according to standard EN 573-3):
• Patent EP 0326337 (Alcan International) describes a plated strip whose base alloy has the composition:
• the low Si content preferably ⁇ 0.05%, allows the formation of a dense layer of Mn precipitates, which can act as a barrier to the diffusion of the silicon of the coating alloy, and increases the strength. corrosion.
• WO 94/22633 is a variant of the previous one which differs only by a higher Cu content (0.6 - 0.9%).
• US Patent 5,350,436 (Kobe Alcoa and Nippondenso) describes a base alloy of composition: Si: 0.3 - 1.3 Cu ⁇ 0.2 Mn: 0.3 - 1.5 Mg ⁇ 0.2 Ti: 0, 02 - 0.3 Fe not mentioned.
• Patent EP 0718072 (Hoogovens Aluminum Walz area) describes a base alloy of composition: Si> 0.15 Fe ⁇ 0.8 Cu: 0.2 - 2 Mn: 0.7 - 1.5 Mg: 0.1 - 0 , 6 with
• a first category of alloys has a very low Si content ( ⁇ 0.15 and preferably ⁇ 0.05 %) with or without a low Fe content, but, in all cases, less demanding than for Si. These very low Si contents ( ⁇ 0.05%) can only be obtained starting from bases pure, which increases manufacturing costs.
• a second category of alloys by questioning the need for a very low Si content to obtain good corrosion resistance, on the contrary has a rather high Si content (0.5 to 0.8%), possibly for compensate for the loss of mechanical strength linked to low contents of Mg and Cu hardening elements.
• the Applicant has determined a range of composition making it possible to improve corrosion resistance without degrading mechanical strength or solderability.
• the subject of the invention is thus a strip, intended for the manufacture of brazed heat exchangers, having an aluminum alloy core of composition (% by mass):
• Si 0.10 - 0.30%, preferably 0.15 - 0.25%
• Cu 0.75 - 1.05%, preferably 0.75 - 1.02%, more preferably 0.75-1.0%
• Mn 1.2 - 1.7%, preferably 1.2 - 1.55%, more preferably 1.25 - 1.4%
• Mg ⁇ 0.03% preferably ⁇ 0.025%, more preferably ⁇ 0.015%
• the subject of the invention is also a method of manufacturing a strip, comprising the successive steps of:
• the thickness of the strip after cold rolling preferably being 0.15 to 3 mm and
• - annealing at a temperature of 240 to 450 ° C, preferably 240 to 380 ° C, with maintenance at the maximum temperature for 10 minutes to 15 hours, preferably for 20 minutes to 3 hours.
• the subject of the invention is also a method for manufacturing a strip according to the present invention, comprising the successive steps of:
• the thickness of the strip after cold rolling preferably being 0.15 to 3 mm and
• - annealing at a temperature of 240 to 450 ° C, preferably 240 to 380 ° C, with maintenance at the maximum temperature for 10 minutes to 15 hours, preferably for 20 minutes to 3 hours.
• the subject of the invention is also a heat exchanger produced at least in part from a strip according to the present invention.
• a subject of the invention is also the use of a strip according to the present invention, for the manufacture of a heat exchanger, said strip exhibiting improved corrosion resistance without degradation of the mechanical resistance or of the solderability.
• FIG. 1 represents the sectional micrographs of the bands after SWAAT test (ASTM G85A3) for the samples of Example 1, after four weeks of exposure. The deepest corrosion sites are shown.
• the mark A corresponds to the sample having a core alloy A (prior art).
• the mark B corresponds to the sample having a core alloy B (according to the invention).
• the mark C corresponds to the sample having a core C alloy (according to the invention).
• FIG. 2 represents the sectional micrographs of the bands after SWAAT test for the samples of Example 2, after two weeks of exposure.
• the E mark corresponds to the sample having an E core alloy (according to the invention).
• the mark F corresponds to the sample having a core alloy F (prior art).
• the strip according to the present invention comprises an aluminum alloy core of composition (% by mass):
• Si 0.10 - 0.30%, preferably 0.15 - 0.25%
• Cu 0.75 - 1.05%, preferably 0.75 - 1.02%, more preferably 0.75-1.0%
• Mn 1.2 - 1.7%, preferably 1.2 - 1.55%, more preferably 1.25 - 1.4%
• Mg ⁇ 0.03% preferably ⁇ 0.025%, more preferably ⁇ 0.015%
• compositional limits of the core alloy can be justified as follows.
• a minimum silicon content of 0.10% makes it possible to avoid using a pure base, the cost of which is high.
• silicon contributes to the mechanical strength by forming Mg2Si precipitates. Beyond 0.30%, silicon can have an unfavorable influence on corrosion resistance, due to the formation of manganese dispersoids AIMnSi and AIMnFeSi.
• An iron content limited to less than 0.25% is also favorable to corrosion resistance and formability, but it is not necessary to go down to very low contents ⁇ 0.15% which would lead to prices high cost.
• Copper is a hardening element which contributes to the mechanical resistance, but above 1.1%, coarse intermetallic compounds are formed on casting which adversely affect the homogeneity of the metal and constitute sites of initiation of the metal. corrosion.
• the manganese is within limits close to those of the alloy 3003; it contributes to mechanical strength and corrosion resistance.
• a limited addition of zinc can have a beneficial effect on corrosion resistance, by modifying the electrochemical mechanisms, especially for the alloys with the highest copper content. However, it must remain below 0.2% to avoid too high a susceptibility to generalized corrosion.
• the core alloy comprises less than 0.1% Ti.
• the core alloy comprises at least 0.05%, more preferably at least 0.06% Ti.
• the strips according to the present invention have a thickness generally comprised from 0.05 to 3 mm, preferably 0.15 to 2.5 mm, depending on the type of part manufactured, and can be plated with a cover alloy, which can be either a brazing alloy or an alloy playing the role of sacrificial anode to protect the part from corrosion, such as a zinc alloy such as the AA7072 alloy.
• a cover alloy which can be either a brazing alloy or an alloy playing the role of sacrificial anode to protect the part from corrosion, such as a zinc alloy such as the AA7072 alloy.
• the brazing aluminum alloy does not include a deliberate addition of Zn, the Zn then preferably being present in an amount corresponding to the impurities, ie less than 0.05% by mass.
• the brazing alloy is of the 4xxx family of alloys with a liquidus temperature sufficiently low compared to the solidus of the core alloy to have a sufficient temperature range for brazing, acceptable mechanical strength and good wettability.
• These alloys can contain addition elements, for example strontium.
• the strip according to the present invention is plated on one or both sides of a brazing aluminum alloy, preferably a 4xxx alloy comprising from 4 to 13%, preferably from 6 to 11% by mass of Si and up to 0.5%, preferably up to 0.3% by mass of Fe.
• a brazing aluminum alloy comprises (% by mass):
• Cu up to 0.4%, preferably up to 0.1%
• Mn up to 0.2%, preferably up to 0.1%
• Mg up to 0.3%, preferably up to 0.1%
• Zn up to 0.2%, preferably up to 0.1%
• composition AA4045 is an aluminum alloy which may be suitable as a brazing alloy according to the present invention. Its composition is, in% by mass: from 9 to 11% of Si, up to 0.8% of Fe, up to 0.30% of Cu, up to 0.05% of Mn, up to 0.05% Mg, up to 0.10% Zn, up to 0.20% Ti, other elements less than 0.05% each and less than 0.15% in total, the remainder being aluminum.
• the preceding composition preferably comprises up to 0.6% Fe.
• the preceding composition preferably comprises up to 0.1% Cu.
• composition AA4343 is an aluminum alloy which may be suitable as a brazing alloy according to the present invention. Its composition is, in% by mass: from 6.8 to 8.2% of Si, up to 0.8% of Fe, up to 0.25% of Cu, up to 0.10% of Mn , up to 0.05% Mg, other elements less than 0.05% each and less than 0.15% in total, the remainder being aluminum.
• the preceding composition preferably comprises up to 0.3% of Fe.
• the preceding composition preferably comprises up to 0.1% of Cu.
• the brazing alloy according to the present invention does not include Mg.
• an aluminum alloy with a sacrificial anode effect in particular an alloy containing zinc, such as the AA7072 alloy.
• the strip according to the present invention is plated on one or two faces of a so-called interlayer aluminum alloy, placed between the core and the possible brazing alloy, preferably comprising (in% by mass):
• Si up to 0.5%, more preferably up to 0.2%;
• Fe up to 0.7%, more preferably up to 0.3%, even more preferably up to 0.2%;
• Mn from 0.3 to 1.4%, more preferably from 0.6 to 0.8%, according to a variant between 1 and 1.3%;
• Cu up to 0.3%, preferably up to 0.1%, even more preferably up to 0.05%;
• the intermediate aluminum alloy of the strip according to the present invention comprises (% by mass): Si ⁇ 0.15%; Fe ⁇ 0.2%; Cu ⁇ 0.1%; Mn from 0.6 to 0.8%; Mg ⁇ 0.02%; other elements ⁇ 0.05% and ⁇ 0.15% in total, remainder of aluminum.
• the intermediate aluminum alloy is an AA3xxx series alloy.
• the strip according to the present invention is a so-called brazing strip, which can be used for the manufacture of different parts of a heat exchanger, for example tubes, plates, collectors, etc.
• the subject of the invention is also a method of manufacturing a strip, comprising the successive steps of:
• the thickness of the strip after cold rolling preferably being 0.15 to 3 mm and
• - annealing at a temperature of 240 to 450 ° C, preferably 240 to 380 ° C, with maintenance at the maximum temperature for 10 minutes to 15 hours, preferably for 20 minutes to 3 hours.
• the subject of the invention is also a method for manufacturing a strip according to the present invention, comprising the successive steps of:
• the thickness of the strip after cold rolling preferably being 0.15 to 3 mm and
• - annealing at a temperature of 240 to 450 ° C, preferably 240 to 380 ° C, with maintenance at the maximum temperature for 10 minutes to 15 hours, preferably for 20 minutes to 3 hours.
• the strip When intended for parts with significant shaping, the strip can be used in the annealed state (O state) by carrying out a final annealing at a temperature between 320 and 380 ° C, in a continuous furnace or in batch oven.
• This annealing leads to the recrystallization of the alloy and improves the formability.
• it is used in the hardened state, which leads to better mechanical resistance, for example an H14 or H24 state (according to standard NF EN 515), the latter state being obtained by a restoration annealing between 250 and 300 ° C, avoiding recrystallization
• the core alloy plate Prior to installing the plating material, the core alloy plate can be homogenized at a temperature of 580 to 630 ° C. This homogenization is favorable to the ductility of the rolled strip and it is recommended when the strip is used in the O state. It promotes the coalescence of the dispersoids with Mn.
• the subject of the invention is also a heat exchanger produced at least in part from a strip according to the present invention.
• a subject of the invention is also the use of a strip according to the present invention, for the manufacture of a heat exchanger, said strip exhibiting improved corrosion resistance without degradation of the mechanical resistance or of the solderability.
• the tapes according to the present invention can be used in the manufacture of radiators, in particular of automobiles, such as engine cooling radiators, oil radiators, heating radiators and charge air coolers, as well as in air conditioning systems.
• Alloy A is a core alloy according to the prior art.
• Alloys B and C are core alloys according to the present invention.
• Alloy D is AA4343 brazing alloy.
• brazing alloy alloy D - 10% of total thickness
• core alloy alloy A, B or C - 80% of total thickness
• brazing alloy alloy D - 10% of total thickness
• the sandwiches were preheated to 500 ° C. and hot rolled at this temperature to a total thickness of 3.5 mm. Then the sandwiches were cold rolled without intermediate annealing to a total thickness of 220 ⁇ m. Finally, the bands obtained were subjected to a restoration annealing to obtain a metallurgical state H24, at 240 ° C. for 2 hours.
• the puncture depth was determined using the SWAAT test (sea water acetic acid test) according to the ASTM G85A3 standard, followed by micrographic observation under an optical microscope (magnification x100) after four weeks of 'exposure. The results are shown in Figure 1.
• FIG. 1 shows that the core alloys according to the present invention make it possible to improve the corrosion resistance compared to the core alloy according to the prior art.
• the mechanical strengths after brazing of the alloys A, B and C described in Table 1 above were measured according to the ISO 6892-1 standard. The results obtained are presented in Table 2 below.
• the core alloy according to the present invention exhibits mechanical strengths of the same order of magnitude, or even improved, compared to the core alloy of the prior art.
• Alloy E is a core alloy according to the present invention.
• Alloy F is a core alloy according to the prior art.
• Alloy D is AA4343 brazing alloy.
• brazing alloy alloy D - 7.5% of total thickness
• core alloy alloy E or F - 85% of total thickness
• brazing alloy alloy D - 7.5% of total thickness
• the sandwiches were preheated to 500 ° C and hot rolled at this temperature to a total thickness of 3.5 mm. Then the sandwiches were cold rolled without intermediate annealing to a total thickness of 400 ⁇ m. Finally, the strips obtained were subjected to annealing to obtain a metallurgical state 0 at 360 ° C. for 1 hour.
• the puncture depth was determined using the SWAAT test (sea water acetic acid test) according to the ASTM G85A3 standard, followed by an observation micrographic under optical microscope (magnification x100) after two weeks of exposure. The results are shown in Figure 2.
• FIG. 2 shows that the core alloy according to the present invention (comprising in particular Cu from 0.75 to 1.05%) makes it possible to improve the corrosion resistance compared with the core alloy according to the prior art.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Organic Chemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Thermal Sciences (AREA)
• Physics & Mathematics (AREA)
• Crystallography & Structural Chemistry (AREA)
• General Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Laminated Bodies (AREA)
• Details Of Heat-Exchange And Heat-Transfer (AREA)
• Conductive Materials (AREA)
• Pressure Welding/Diffusion-Bonding (AREA)
• Metal Rolling (AREA)

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• 2019
  • 2019-03-04 FR FR1902177A patent/FR3093450A1/fr active Pending
  • 2019-03-05 FR FR1902257A patent/FR3093451B1/fr active Active
• 2020
  • 2020-02-27 JP JP2021552542A patent/JP2022522881A/ja active Pending
  • 2020-02-27 EP EP20719682.5A patent/EP3934908A1/de active Pending
  • 2020-02-27 KR KR1020217031370A patent/KR20210135271A/ko unknown
  • 2020-02-27 US US17/436,003 patent/US11932922B2/en active Active
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