JP2014077179A - High strength aluminum alloy brazing sheet and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aluminum alloy brazing sheet suitable as a fluid passage component for a heat exchanger of transportation equipment, and having good brazability and high strength.SOLUTION: The aluminum alloy brazing sheet contains a core material comprising an aluminum alloy and a brazing material comprising an Al-Si-based alloy made crud to at least one side of core material surface, and the core material is the aluminum alloy containing Si:0.3 to 1.5%, Fe:0.05 to 1.0%, Mg:0.05 to 0.6% and the balance Al, the brazing material is the aluminum alloy containing Si:2.5 to 13.0%, Fe0.05 to 2.0% (each by mass%) and the balance Al, the core material has an average area of 1 μmor less and a number density of 1/μmor less when measured Mg-containing intermetallic compound having 0.1 μmor more on the arbitrary section before brazing.

Description

  The present invention relates to an aluminum alloy brazing sheet used for transportation equipment, in particular, a heat exchanger for automobiles, and the like, and preferably a high-strength aluminum alloy brazing sheet used as a passage constituent material for high-temperature compressed air or refrigerant and its production Regarding the method.

  Aluminum alloys are lightweight and have high thermal conductivity, and can be realized with high corrosion resistance by appropriate processing. Therefore, they are used in automotive heat exchangers such as radiators, condensers, evaporators, heaters, and intercoolers. As materials for flow path forming parts of these automotive heat exchangers, a core material made of an aluminum alloy, and an aluminum alloy brazing sheet in which the core material is clad with a brazing material or a sacrificial anode material are used. Specifically, an Al—Mn alloy or the like represented by JIS3003 alloy is used as a core material, and a brazing material such as an Al—Si alloy or a sacrificial anode material such as an Al—Zn alloy is clad on one surface. A two-layer clad material or a three-layer clad material in which a sacrificial anode material such as an Al—Zn alloy is clad on the inner surface side of the core material and a brazing material such as an Al—Si alloy is clad on the atmosphere side is used. .

  The heat exchanger is usually joined by combining such clad material and corrugated fins and brazing at a temperature of about 600 ° C. When this flow path forming component is broken and penetrated after being mounted on a vehicle as a heat exchanger, leakage of cooling water and refrigerant circulating inside occurs. Therefore, in order to improve the product life, an aluminum alloy brazing sheet having excellent strength after brazing is indispensable.

  By the way, in recent years, the demand for weight reduction of automobiles has increased, and in order to meet this demand, weight reduction of automobile heat exchangers has also been demanded. For this reason, reduction in the thickness of each member constituting the heat exchanger has been studied, and accordingly, it is necessary to further improve the strength of the aluminum alloy brazing sheet after brazing.

  For example, a two-layer or three-layer tube used as a core material such as an Al-Mn alloy represented by the above-mentioned JIS3003 alloy, which is widely used as a tube material for heat exchangers constituting radiators and heaters for transportation equipment As for the material, the strength after brazing is about 110 MPa, which is insufficient in strength, and the improvement is demanded.

Here, as a means for increasing the strength of the brazing sheet, increasing the strength of the core material is effective, and a strengthening method by age hardening by adding Mg has been proposed. This is because Mg is added to the core material to form an intermetallic compound (Mg ₂ Si) together with Si added to the core material and Si diffused from the brazing material during brazing (age hardening), As a result, the strength of the core material is increased.

  About the reinforcement method of the core material by Mg addition of this core material, for example, in Patent Document 1, 0.8% or less of Mg is added to the core material, and natural aging after brazing or artificial aging at 100 to 250 ° C. is high. Strength is said to be obtained. Moreover, in patent document 2, 0.05-0.6% of Mg is added to a core material, and the temperature when carrying out artificial aging after brazing or carrying and drive | working on a transport apparatus is 120 to 200 degreeC. In some cases, it is age-hardened and high strength is obtained.

Japanese translation of PCT publication No. 2002-513085 JP 2011-042823 A

  However, according to the present inventors, when a conventional brazing sheet in which Mg is added to the core material is used, the strength increasing effect due to age hardening may not be sufficiently exhibited in a general brazing heating time. There is a problem that there is. Regarding the heating time for brazing, it is common to set the holding time at 600 ° C. to about 3 minutes in the manufacture of heat exchangers, but age hardening is often insufficient with this heating time. . In recent years, in order to increase the efficiency of production of heat exchangers, technological development has been progressing in which brazing heat treatment is performed in a shorter time than before. In view of this background, there is a need for a brazing sheet that can sufficiently exhibit the effect of increasing the strength of the core material by age hardening even when the heating time for brazing is short, as well as for a general brazing heating time. The

  Then, an object of this invention is to provide the aluminum alloy brazing sheet which has favorable brazing property and high intensity | strength. In addition, an aluminum alloy brazing sheet having good corrosion resistance is provided as needed. In particular, an object of the present invention is to provide an aluminum alloy brazing sheet that can be suitably used as a fluid passage constituent material of a heat exchanger for transportation equipment such as an automobile, and a method for producing the same.

  The inventors of the present invention have studied the above-mentioned problems, and have studied factors that do not cause sufficient age hardening in a conventional brazing sheet to which a core material made of an aluminum alloy added with Mg is applied. As a result, insufficient solid solution of Mg in the matrix during heating in the brazing treatment was a cause of insufficient age hardening. In order to generate precipitates for age hardening, Mg, which is a constituent element of the precipitates, must be dissolved in the alloy matrix as a previous step. Here, the core material made of an aluminum alloy to which Mg is added is in a state where an intermetallic compound containing Mg is precipitated and dispersed before brazing. And in this aluminum alloy, Mg is dissolved from the intermetallic compound containing Mg by the heat | fever of brazing process. In the conventional brazing sheet, when the heating time of the brazing treatment is short, age hardening becomes insufficient because Mg could not be completely dissolved during heating.

  Therefore, in order to sufficiently develop age hardening in the aluminum alloy as the core material, it is necessary to dissolve Mg in the intermetallic compound even in a short heating time. Thus, as a result of extensive research, the present inventors have found that a brazing sheet provided with an aluminum alloy core material having a specific alloy composition and having a specific metal structure is suitable for this purpose. It came to be completed.

That is, the present invention relates to an aluminum alloy brazing sheet comprising a core material made of an aluminum alloy and a brazing material made of an Al—Si alloy clad on at least one surface of the core material. It is an aluminum alloy containing 3-1.5 mass%, Fe: 0.05-1.0 mass%, Mg: 0.05-0.6 mass%, the balance being Al and unavoidable impurities, Si: 2.5 to 13.0 mass%, Fe 0.05 to 2.0 mass%, an aluminum alloy composed of the balance Al and inevitable impurities, and the core material includes Mg in an arbitrary cross section before brazing. when area a intermetallic compound containing the measured ones 0.1 [mu] m ² or more and the area of the average 1 [mu] m ² or less, and their number density Is a high strength aluminum alloy brazing sheet, characterized in that one / [mu] m ² or less.

  Hereinafter, the aluminum alloy brazing sheet and the manufacturing method thereof according to the present invention will be described in detail. In addition, the performances related to strength and corrosion resistance are all after brazing. Brazing is usually performed by heating to about 600 ° C. and then air cooling.

  As described above, the aluminum alloy brazing sheet according to the present invention is obtained by cladding a brazing material made of an aluminum alloy having a predetermined composition on a core material made of an aluminum alloy having a predetermined composition. The core material is clad with a sacrificial anode material as necessary. In the following description, each of these configurations will be described. Further, in the present specification, when the alloy composition is simply “%”, it means mass% (mass%).

A. The core material is an aluminum alloy containing Si: 0.3 to 1.5 mass%, Fe: 0.05 to 1.0 mass%, Mg: 0.05 to 0.6 mass%, and the balance Al and inevitable impurities. It is. And this aluminum alloy has the characteristics about the metal structure before brazing, and the state of the intermetallic compound containing Mg is specified.

  Si dissolves in the aluminum matrix and improves the strength by solid solution strengthening. When artificial aging is applied after brazing, Si forms an aging precipitate together with Mg to improve the strength. The content of Si is 0.3 to 1.5 mass%. If the content is less than 0.1%, the effect is not sufficient, and if it exceeds 1.5%, the melting point of the core material is lowered, and the core material is eroded by brazing during brazing. A preferable content of Si is 0.3 to 1.0%.

  Fe easily forms a compound having a size capable of forming a recrystallization nucleus. In order to increase the crystal grain size after brazing and suppress the erosion of the core material by brazing during brazing, the Fe content is 0.05 to 1.0%. If the content is less than 0.05%, high-purity aluminum ingots must be used, and the cost is high. If the content exceeds 1.0%, the crystal grain size after brazing becomes fine, and the corrosion of the brazing material into the core material occurs. Arise. A preferable content of Fe is 0.1 to 0.7%.

  Mg is solid-solved in the aluminum matrix and improves strength by solid solution strengthening, and when artificial aging is applied after brazing, it forms aging precipitates together with Si and Cu and improves strength. The content of Mg is 0.05 to 0.6%. If the content is less than 0.05%, the effect is not sufficient, and if it exceeds 0.6%, brazing may be difficult. A preferable content of Mg is 0.15 to 0.4%.

  The core material may contain one or more selected from the group consisting of Mn, Cu, Ti, Zr, Cr, and V, in addition to the above essential constituent elements.

  Mn forms an Al-Mn-Si based compound with Si and improves the strength by dispersion strengthening, and solid solution in the aluminum matrix improves the strength by solid solution strengthening, so it is preferable to add Mn. . The Mn content is 0.05 to 2.0%. If the content is less than 0.05%, the effect may not be sufficiently obtained. If the content exceeds 2.0%, a giant compound tends to be formed at the time of casting, and the plastic workability is lowered. A more preferable content of Mn is 0.1 to 1.8%.

  Cu improves the strength by solid solution strengthening, and when artificial aging is applied after brazing, aging precipitates are formed together with Si and Mg, and the strength improvement by aging is promoted, so it is preferable to add Cu. The Cu content is 0.05 to 2.0%. If the content is less than 0.05%, the effect may not be sufficiently obtained. If the content exceeds 2.0%, the aluminum alloy is more likely to crack during casting. A more preferable content of Cu is 0.3 to 1.5%.

  Since Ti improves strength by solid solution strengthening, Ti is preferably contained. The content of Ti is preferably 0.05 to 0.3%. If the content is less than 0.05%, the effect may not be sufficiently obtained. If the content exceeds 0.3%, a giant compound is likely to be formed, and the plastic workability may be lowered. A more preferable content of Ti is 0.1 to 0.2%.

  Zr is preferably contained because it improves the strength by solid solution strengthening and acts on the coarsening of crystal grains after brazing by precipitation of an Al-Zr compound. The Zr content is preferably 0.05 to 0.3%. If the content is less than 0.05%, the effect may not be sufficiently obtained. If the content exceeds 0.3%, a giant compound is likely to be formed, and the plastic workability may be lowered. A more preferable content of Zr is 0.1 to 0.2%.

  Cr is preferably contained because it improves the strength by solid solution strengthening and acts on the coarsening of crystal grains after brazing by precipitation of an Al-Cr compound. The content of Cr is preferably 0.05 to 0.3%. If the content is less than 0.05%, the effect may not be sufficiently obtained. If the content exceeds 0.3%, a giant compound is likely to be formed, and the plastic workability may be lowered. The more preferable content of Cr is 0.1 to 0.2%.

  V is preferably contained because it improves the strength by solid solution strengthening. The content of V is preferably 0.05 to 0.3%. If the content is less than 0.05%, the effect may not be sufficiently obtained. If the content exceeds 0.3%, a giant compound is likely to be formed, and the plastic workability may be lowered. A more preferable content of V is 0.1 to 0.2%.

  These Mn, Cu, Ti, Zr, Cr, and V only need to be added to the core material as necessary. Further, inevitable impurities may be contained in an amount of 0.05% or less and 0.15% or less in total.

The core material made of the aluminum alloy described above is also characterized in its material structure. This metal structure is an intermetallic compound containing Mg in an arbitrary cross section before brazing, and when an area of 0.1 μm ² or more is measured, the average area is 1 μm ² or less, and The number density is 1 piece / μm ² or less. Then, next, this metal structure is demonstrated in detail.

  In the core material of the brazing sheet before brazing, Mg is present in an intermetallic compound state together with Si and Cu. This intermetallic compound containing Mg is generated by heat input during the manufacturing process. The brazing sheet of the present invention intends to obtain high strength by forming Mg with aging precipitates together with Si and Cu by forming Mg in the core material in solution at the time of brazing and then performing artificial aging.

  Here, when the heating time of the brazing treatment is short (as described above, it is usually about 3 minutes at 600 ° C.), the solution treatment time is short, so the intermetallic compound containing Mg If is coarse, it is not sufficiently solutionized in the brazing process. In that case, even if artificial aging treatment is performed after brazing, age hardening does not occur effectively, and a sufficient effect cannot be obtained.

Therefore, in the present invention, an intermetallic compound containing coarse Mg as a metal structure before brazing is regulated. That is, in an arbitrary cross section of the core material before brazing, when an intermetallic compound containing Mg having an area of 0.1 μm ² or more is measured, the average area is 1 μm ² or less, and the number thereof When the density is 1 piece / μm ² or less, Mg is sufficiently solutionized by brazing, and sufficient strength can be obtained by artificial aging after brazing. On the other hand, in an arbitrary cross section of the core material before brazing, when an intermetallic compound containing Mg and having an area of 0.1 μm ² or more is measured, the average area is larger than 1 μm ² or the number thereof When the density is larger than 1 piece / μm ² , Mg is not sufficiently dissolved during brazing, and sufficient strength cannot be obtained even if artificial aging is applied after brazing.

In addition, since the intermetallic compound containing Mg whose area is less than 0.1 μm ² is solid-solubilized at the time of brazing, there is no adverse effect even if it exists. In addition, regarding the compound containing Mg, all those having an area of 1 μm ² or more should be regulated, but in the aluminum alloy brazing sheet of the present invention, an intermetallic compound containing Mg having an area exceeding 100 μm ² is generated. The possibility is very low.

B. Brazing material In the aluminum alloy brazing sheet according to the present invention, brazing material is clad on at least one surface of the core material. This brazing material is an aluminum alloy containing Si: 2.5 to 13.0 mass%, Fe 0.05 to 2.0 mass%, and the balance being Al and inevitable impurities. The essential additive elements for the aluminum alloy that is the brazing material are Si and Fe.

  Si lowers the melting point to form a liquid phase and enables brazing. The Si content is 2.5 to 13.0%. If it is less than 2.5%, the resulting liquid phase is small and brazing becomes difficult to function. On the other hand, if it exceeds 13.0%, for example, the amount of Si diffusing into the counterpart material such as fins becomes excessive, and the counterpart material may be melted. The preferable content of Si is 3.5 to 12.0%, and the more preferable content is 7.0 to 12.0%.

  Fe forms an Al—Fe—Mn—Si compound together with Si and Mn, and improves the strength by dispersion strengthening. The addition amount of Fe is 0.05 to 2.0%. If the content is less than 0.05%, high-purity aluminum ingots must be used, resulting in high costs. On the other hand, if it exceeds 2.0%, a giant compound tends to be formed during casting, and the plastic workability is lowered. A preferable content of Fe is 0.05 to 1.5%.

  The brazing material can contain Zn, Cu, Mn, Ti, Zr, Cr, V, Na, and Sr as optional additive elements.

  Zn is preferably contained because the potential can be reduced and the corrosion resistance can be improved by the sacrificial anode effect by forming a potential difference with the core material. The content of Zn is preferably 0.3 to 8.0%. If it is less than 0.3%, the effect may not be sufficiently obtained. If it exceeds 8.0%, for example, Zn is concentrated in the joint portion with the counterpart material such as a fin, and this preferentially corrodes and the counterpart material becomes May peel. The more preferable content of Zn is 0.5 to 3.0%.

  Cu improves the strength by solid solution strengthening. The Cu content is preferably 0.05 to 2.0%. If it is less than 0.05%, the effect may not be sufficiently obtained. If it exceeds 2.0%, the possibility of occurrence of cracks in the aluminum alloy during casting increases. The Cu content is more preferably 0.3 to 1.5%. If the brazing material contains Zn, Cu makes the brazing material noble and loses the sacrificial anticorrosive effect, so the content is preferably 0.05 to 0.5%.

  Mn forms an Al-Mn-Si based compound with Si and improves the strength by dispersion strengthening, and solid solution in the aluminum matrix improves the strength by solid solution strengthening, so it is preferable to add Mn. . The Mn content is 0.05 to 2.0%. If the content is less than 0.05%, the effect may not be sufficiently obtained. If the content exceeds 2.0%, a giant compound tends to be formed at the time of casting, and the plastic workability is lowered. A more preferable content of Mn is 0.1 to 1.8%.

  Since Ti improves strength by solid solution strengthening, Ti is preferably contained. The content of Ti is preferably 0.05 to 0.3%. If the content is less than 0.05%, the effect may not be sufficiently obtained. If the content exceeds 0.3%, a giant compound is likely to be formed, and the plastic workability may be lowered. A more preferable content of Ti is 0.1 to 0.2%.

  Zr is preferably contained because it improves the strength by solid solution strengthening and acts on the coarsening of crystal grains after brazing by precipitation of an Al-Zr compound. The Zr content is preferably 0.05 to 0.3%. If the content is less than 0.05%, the effect may not be sufficiently obtained. If the content exceeds 0.3%, a giant compound is likely to be formed, and the plastic workability may be lowered. A more preferable content of Zr is 0.1 to 0.2%.

  Cr is preferably contained because it improves the strength by solid solution strengthening and acts on the coarsening of crystal grains after brazing by precipitation of an Al-Cr compound. The content of Cr is preferably 0.05 to 0.3%. If the content is less than 0.05%, the effect may not be sufficiently obtained. If the content exceeds 0.3%, a giant compound is likely to be formed, and the plastic workability may be lowered. The more preferable content of Cr is 0.1 to 0.2%.

  V is preferably contained because it improves the strength by solid solution strengthening. The content of V is preferably 0.05 to 0.3%. If the content is less than 0.05%, the effect may not be sufficiently obtained. If the content exceeds 0.3%, a giant compound is likely to be formed, and the plastic workability may be lowered. A more preferable content of V is 0.1 to 0.2%.

  By adding Na and Sr to the Al—Si brazing material, the size of the Si particles in the Al—Si brazing material is finely and uniformly dispersed to control the generation of coarse Si particles. In order to suppress local melting and erosion of the joining portion, it is preferably contained. The content of Na or Sr is preferably 0.001 to 0.05%. If it is less than 0.001% of Na or Sr, the effect may not be sufficiently obtained. On the other hand, since Na and Sr promote the oxidation of aluminum, if it exceeds 0.05%, the oxidation of the braze proceeds at the time of brazing, and the flowability and brazeability of the braze are lowered. The content of Na or Sr is more preferably 0.005 to 0.02%.

  These Zn, Cu, Mn, Ti, Zr, Cr, V, Na, and Sr may be added in the brazing material if necessary. Further, inevitable impurities may be contained in an amount of 0.05% or less and 0.15% or less in total. The brazing material is clad on at least one surface of the core material.

C. Sacrificial anode material The aluminum alloy brazing sheet according to the present invention may be one in which a brazing material is clad on one surface of a core material and a sacrificial anode material made of an aluminum alloy is clad on the other surface. For example, when high corrosion resistance is required in the environment where the heat exchanger is used, the core material is clad on one surface. This sacrificial anode material contains Zn: 0.3-8.0 mass%, Si: 0.05-1.5 mass%, Fe: 0.05-2.0 mass%, and consists of the balance Al and inevitable impurities. Aluminum alloy. The essential additive elements for the aluminum alloy that is the sacrificial anode material are Zn, Si, and Fe.

  Zn can lower the potential, and can improve the corrosion resistance by the sacrificial anode effect by forming a potential difference with the core material. The Zn content is 0.3 to 8.0%. If the content is less than 0.3%, the effect is not sufficient, and if it exceeds 8.0%, the corrosion rate is increased, the sacrificial anode material disappears early, and the corrosion resistance is lowered. The preferable content of Zn is 0.5 to 6.0%.

Si forms an Al—Fe—Mn—Si compound together with Fe and Mn and improves strength by dispersion strengthening, or improves the strength by solid solution strengthening by dissolving in an aluminum matrix. Moreover, it reacts with Mg diffusing from the core material during brazing to form a Mg ₂ Si compound, thereby improving the strength. The Si content is 0.05 to 1.5%. If the content is less than 0.05%, high-purity aluminum ingots must be used, resulting in high costs. On the other hand, if it exceeds 1.5%, the potential of the sacrificial anode material is made noble, so that the sacrificial anode effect is inhibited and the corrosion resistance is lowered. A preferable content of Si is 0.05 to 1.2%.

  Fe forms an Al—Fe—Mn—Si compound together with Si and Mn, and improves the strength by dispersion strengthening. The addition amount of Fe is 0.05 to 2.0%. If the content is less than 0.05%, high-purity aluminum ingots must be used, resulting in high costs. On the other hand, if it exceeds 2.0%, a giant compound tends to be formed during casting, and the plastic workability is lowered. A preferable content of Fe is 0.05 to 1.5%.

  The sacrificial anode material may contain one or more selected from the group consisting of Mn, Mg, Ti, Zr, Cr, and V in addition to the above essential constituent elements.

  Mn forms an Al-Mn-Si compound together with Si, improves strength by dispersion strengthening, and improves the strength by solid solution strengthening by solid solution strengthening in the aluminum matrix, so it is preferable to contain Mn. . The Mn content is preferably 0.05 to 2.0%. If it exceeds 2.0%, a huge compound is likely to be formed at the time of casting, which may lower the plastic workability. In addition, since the potential of the sacrificial anode material is made noble, the sacrificial anode effect is inhibited and the corrosion resistance is lowered. There is a case. On the other hand, if it is less than 0.05%, the effect may not be sufficiently obtained. A more preferable content of Mn is 0.05 to 1.5%.

Mg improves the strength by precipitation of Mg ₂ Si. In addition to improving the strength of the sacrificial anode material itself, brazing causes Mg to diffuse into the core material, thereby improving the strength of the core material. For these reasons, it is preferable to contain Mg. The content of Mg is preferably 0.5 to 3.0%. If it is less than 0.5%, the effect may not be sufficiently obtained. If it exceeds 3.0%, it may be difficult to perform pressure bonding during hot clad rolling. A more preferable content of Mg is 0.5 to 2.0%. In addition, since Mg inhibits the brazing property in Nocolok brazing, if the sacrificial anode material contains 0.5% or more of Mg, Noclock brazing cannot be performed on the sacrificial anode material. In this case, it is necessary to use means such as welding for joining the tubes, for example.

  Ti is preferably contained because it can improve the strength by solid solution strengthening and can improve the corrosion resistance. The content of Ti is preferably 0.05 to 0.3%. If the amount is less than 0.05%, the effect may not be sufficiently obtained. If the amount exceeds 0.3%, a giant compound is likely to be formed, and the plastic workability may be lowered. A more preferable content of Ti is 0.05 to 0.2%.

  Zr is preferably contained because it improves the strength by solid solution strengthening and acts on the coarsening of crystal grains after brazing by precipitation of an Al-Zr compound. The Zr content is preferably 0.05 to 0.3%. If the content is less than 0.05%, the effect may not be sufficiently obtained. If the content exceeds 0.3%, a giant compound is likely to be formed, and the plastic workability may be lowered. A more preferable content of Zr is 0.1 to 0.2%.

  Cr is preferably contained because it improves the strength by solid solution strengthening and acts on the coarsening of crystal grains after brazing by precipitation of an Al-Cr compound. The content of Cr is preferably 0.05 to 0.3%. If the content is less than 0.05%, the effect may not be sufficiently obtained. If the content exceeds 0.3%, a giant compound is likely to be formed, and the plastic workability may be lowered. The more preferable content of Cr is 0.1 to 0.2%.

  V is preferably contained because it can improve strength by solid solution strengthening and can improve corrosion resistance. The content of V is preferably 0.05 to 0.3%. If it is less than 0.05%, the effect may not be sufficiently obtained, and if it exceeds 0.3%, a giant compound tends to be formed, and plastic workability may be lowered. A more preferable content of V is 0.05 to 0.2%.

  As for these Mn, Mg, Ti, Zr, Cr, and V, at least one kind may be added to the sacrificial anode material as necessary. Further, inevitable impurities may be contained in an amount of 0.05% or less and 0.15% or less in total. Note that the sacrificial anode material is clad on one surface of the core material when, for example, high corrosion resistance is required in the usage environment of the heat exchanger.

  Next, the manufacturing method of the aluminum alloy brazing sheet which concerns on this invention is demonstrated.

  The manufacturing process of the aluminum alloy brazing sheet of the present invention includes a step of casting a core material, a brazing material as a skin material, and an aluminum alloy as a sacrificial anode material, and is cast on at least one surface of the cast core material. A mating step of combining the skin materials into a mating material, a heating step of heating and holding the mating material after the mating step, a clad hot rolling step of hot rolling the mating material after the heating step, and a cold after the clad hot rolling It includes a cold rolling process for rolling and an annealing process for performing annealing at least once during or after the cold rolling process. In the joining step, the brazing material may be joined with only one side or both sides of the core material with the brazing material, or with the brazing material on one side of the core material and with the sacrificial anode material on the other side. In addition, when the brazing material or the sacrificial anode material skin is combined, there is no particular limitation on the method of making them to a predetermined thickness, but it is usually performed by hot rolling the ingot at about 400 ° C to 550 ° C. .

  And as already stated, the aluminum alloy brazing sheet of the present invention defines the average area and number density of the compound containing Mg in the core material before brazing, and reduces coarse intermetallic compounds. Features. In order to realize such a state, in the manufacturing process of the aluminum alloy brazing sheet of the present invention, it is important to control the material temperature in the heating process and the clad hot rolling process.

  The inventors have intensively studied the relationship between the material temperature in the manufacturing process and the state of the intermetallic compound containing Mg, and as a result, when the intermetallic compound is 300 to 480 ° C. We found that it tends to be coarse. And based on this knowledge, the suitable control range after a heating process, a clad hot rolling process, and a clad hot rolling process was discovered in the above-mentioned manufacturing process.

That is, in the heating step, the heating temperature is 480 to 550 ° C., and the heating and holding time is 0 to 10 hours. By doing in this way, the compound containing Mg originally distributed in the core material ingot is dissolved in the aluminum matrix, and during this heating, a coarse compound containing Mg having an area of 0.1 μm ² or more Since no precipitation occurs, it is possible to obtain a state in which the average area is 1 μm ² or less and the number density is 1 piece / μm ² or less.

  When this heating temperature is less than 480 ° C., a coarse compound containing Mg is produced during heating, and the area and number density may become too large. On the other hand, when the heating temperature exceeds 550 ° C., the combined brazing material may be melted. In addition, when the heating time exceeds 10 hours, there is no problem in terms of material performance, but since the heating time is too long, productivity is significantly impaired. The heating temperature is more preferably 500 to 550 ° C.

Further, during the hot rolling of the clad, precipitation due to the introduction of strain due to hot rolling is induced, and a coarse compound containing Mg is more likely to be generated. Therefore, stricter temperature control is required. In the manufacturing method according to the present invention, the temperature of the laminated material at the start of hot rolling is 480 to 550 ° C., and the time during which the temperature of the laminated material is 300 to 480 ° C. at the time of clad hot rolling is 30 minutes or less. Thereby, when the compound containing Mg whose area is 0.1 μm ² or more is measured, the average area is 1 μm ² or less, and the number density is 1 piece / μm ² or less.

  When the temperature of the laminated material at the start of clad hot rolling is less than 480 ° C., a coarse compound containing Mg is generated during heating, and its area and number density may become too large. On the other hand, when the temperature of the bonding material at the start of hot rolling exceeds 550 ° C., the combined brazing material may be melted. Moreover, when the time when the temperature of the laminated material is 300 to 480 ° C. exceeds 30 minutes during clad hot rolling, a coarse compound containing Mg is generated during clad hot rolling, and the area and number density are large. It may become too much. When the time during which the temperature of the laminated material is 300 to 480 ° C. during the hot rolling of the clad is short, there is no problem in terms of the performance of the material. The material may be too large and cracks may occur in the material.

Furthermore, since the material temperature after hot rolling of the clad becomes high and the production of a compound containing Mg may proceed, it is also important to control the material temperature after hot rolling. Therefore, in the present invention, the material temperature at the end of hot rolling is set to 320 ° C. or less. If the material temperature after hot rolling is 320 ° C. or less, the formation of a compound containing Mg after hot rolling is unlikely to occur, and when a compound containing Mg having an area of 0.1 μm ² or more is measured, the compound containing Mg The average area is 1 μm ² or less, and the number density is 1 / μm ² or less.

  When the material temperature after clad hot rolling exceeds 320 ° C., a coarse compound containing Mg is produced after hot rolling, and the area and number density may become too large. When the temperature after hot rolling is low, there is no problem in terms of the performance of the material, but it is difficult to control the temperature to be 150 ° C. or less with normal hot rolling equipment.

  As described above, in the manufacturing process of the aluminum alloy brazing sheet according to the present invention, it is necessary to control the material temperature after the heating process, the clad hot rolling process, and the clad hot rolling process after the alignment process.

  The clad material after the clad hot rolling step is then subjected to cold rolling, but may be subjected to intermediate annealing about once or twice before reaching the final thickness. The intermediate annealing is preferably performed at a temperature of 150 to 550 ° C. The rolling rate from the last intermediate annealing to the final plate thickness is usually about 10 to 80%. The final plate thickness is usually about 0.1 to 0.6 mm. Further, after cold rolling to the final thickness, finish annealing may be performed for the purpose of improving formability. The finish annealing is preferably performed at 150 to 550 ° C. In the intermediate annealing process and the finish annealing process, a batch type furnace or a continuous type furnace may be used.

  In addition, in the manufacturing process of the aluminum alloy brazing sheet which concerns on this invention, you may pass through a homogenization process process after the casting process of a core material for the purpose of the moldability improvement before brazing. The homogenization treatment is preferably performed at a temperature of 480 to 620 ° C. and a holding time of 1 to 20 hours. When the temperature is lower than 480 ° C., a coarse compound containing Mg is generated during heating, and the area and number density may be too large. When the temperature exceeds 620 ° C., the core material ingot may be melted. When the holding time is less than 1 hour, the effect of the homogenization treatment is not sufficient. When holding time is 20 hours or more, since time is too long, manufacture will be impaired remarkably.

  Further, the thickness of the aluminum alloy brazing sheet according to the present invention, the clad rate of the brazing material layer and the sacrificial anode material layer is not particularly limited, but usually when used as a tube material of a heat exchanger for transportation equipment, It can be set as a thin brazing sheet of 0.6 mm or less. However, it is not limited to the plate thickness within this range, and can be used as a relatively thick material of 0.6 to 5 mm. The single-sided cladding ratio in the brazing material layer and the sacrificial anode material layer is usually about 3 to 20%.

  Here, regarding the aluminum alloy brazing sheet according to the present invention, a method of brazing and joining will be described. Regarding this brazing and joining process, the general brazing condition is that the holding is usually performed at about 600 ° C. for about 3 to 5 minutes. FIG. 1 schematically shows a temperature chart at the time of brazing, but it is maintained at 580 ° C. or higher for the brazing condition of holding the temperature around 600 ° C. for about 3 to 5 minutes. It is a common temperature control method that the time is longer than 12 minutes.

  In the aluminum alloy brazing sheet of the present invention, the effect of the invention is exhibited to the maximum when brazing is performed for a short time, specifically, when the time of holding at 580 ° C. or higher during brazing is 12 minutes or less. be able to. Thus, when the time maintained at 580 ° C. or higher is shorter than conventional, the conventional aluminum alloy brazing sheet has a large area and number density of the compound containing Mg in the core material before brazing, The solution of Mg became insufficient, and it was difficult to obtain creep resistance even after subsequent aging treatment. On the other hand, in the aluminum alloy brazing sheet of the present invention, since the area and number density of the compound containing Mg and Si are reduced, Mg is sufficiently solutionized even after brazing for a short time. Excellent creep resistance can be obtained by aging treatment.

  Of course, even if the aluminum alloy brazing sheet of the present invention is brazed for a long time, creep resistance equivalent to or higher than that of the prior art can be obtained. However, as a brazing condition for achieving both the shortening of the brazing time and ensuring the creep resistance after brazing and maximizing the effects of the present invention, the brazing condition is set to 580 ° C. or higher during brazing. The holding time is 12 minutes or less. More preferably, it is 5 minutes or less.

  In addition, the material temperature which reaches | attains in brazing is 580-620 degreeC. If the temperature is lower than 580 ° C., the amount of the flowing wax may be insufficient, which may cause brazing failure. If the temperature is higher than 620 ° C., the core material and the fins may be eroded by the wax. Moreover, it is preferable that the cooling rate after a heating is 30 degreeC / min or more in the cooling rate to 300 degreeC. When the cooling rate to 300 ° C. is less than 30 ° C./min, precipitation of a compound containing Mg and Si may occur during cooling, and sufficient creep resistance may not be obtained even after artificial aging treatment is performed thereafter. . The cooling rate to 300 ° C. is more preferably 50 ° C./min or more.

  Next, the artificial aging process after brazing will be described. As already mentioned, the aluminum alloy brazing sheet of the present invention is solid-dissolved in the aluminum matrix by brazing, so that after the artificial aging, Mg becomes an aging precipitate together with Si and Cu and age-hardened. And creep resistance can be improved. As the aging precipitates are finer and denser, the effect is larger, and as the aging temperature is lower, the aging precipitates formed are denser and finer. However, if the aging temperature is too low, the rate at which aging precipitates are formed is slow, and it takes a long time to obtain sufficient creep resistance.

  The conditions of the artificial aging treatment are a temperature of 160 to 180 ° C. and a time of 1 minute to 10 hours. When the temperature is lower than 160 ° C., the rate at which aging precipitates are formed is slow, and sufficient creep resistance cannot be obtained in an industrially realistic time. When the temperature exceeds 180 ° C., the aging precipitate becomes coarse and sufficient creep resistance cannot be obtained. When the time is less than 1 minute, the time for forming an aging precipitate is insufficient, and sufficient creep resistance cannot be obtained. If the time exceeds 10 hours, the heat exchanger may be over-aged due to the heat that is loaded on the transportation equipment and the transportation equipment travels, and sufficient creep resistance may not be obtained. . In addition, as for the more preferable conditions of artificial aging treatment, temperature is 170-180 degreeC and time is 1 hour-5 hours.

  The aluminum alloy brazing sheet of the present invention is suitable as a constituent material of a heat exchanger for transportation equipment such as an automobile. Here, according to the study by the inventors, the heat exchanger using the aluminum alloy brazing sheet of the present invention has the effect of the present invention due to the temperature and generated strain when the transport device travels after being loaded on the transport device. Can be maximized.

  That is, as described above, the aluminum alloy brazing sheet of the present invention can obtain excellent creep resistance by being artificially aged in the flow path forming component in the heat exchanger after brazing, When the transport device travels after being loaded on the transport device, if this flow path forming component is exposed to an appropriate temperature, age hardening also occurs in the meantime. And when an appropriate distortion | strain generate | occur | produces here in a flow-path formation component, the age hardening of a brazing sheet core material is further accelerated | stimulated and more outstanding durability can be acquired.

  Appropriate conditions at the time of traveling of the transportation apparatus are that the highest temperature of the flow path forming component is 80 ° C. to 190 ° C., and that the flow path forming component is strained by 0.4% or more.

  When the maximum temperature reached is less than 80 ° C., age hardening hardly occurs, and thus superior durability cannot be obtained. If the highest temperature exceeds 190 ° C., the brazing sheet core material becomes over-aged during travel of the transportation equipment, and thus it is not possible to obtain more excellent durability. In addition, when the strain applied to the flow path forming component is less than 0.35%, the age hardening of the brazing sheet core material that occurs during travel of the transportation equipment is not sufficiently accelerated by the strain, and better durability can be obtained. Can not. The highest ultimate temperature of the flow path forming component is more preferably 120 to 180 ° C., and the generated strain is more preferably 0.40% or more.

  In addition, as a cause of the distortion generate | occur | produced when a transport apparatus drive | works, it is based on the repetition of heating and cooling of a heat exchanger, for example. As a specific example, the engine coolant flowing into the radiator tube has a high temperature of about 100 ° C. at the maximum. Then, the tube tends to extend in the longitudinal direction due to thermal expansion. At this time, since the shape of the entire heat exchanger is constrained by a plate or the like, the length of the tube cannot be changed, and as a result, a compressive strain is applied to the tube by the amount of thermal expansion. This compression strain promotes age hardening. However, the cause of the distortion generated when the transportation device travels is not limited to the above, and may be caused by, for example, an internal pressure due to a substance in a tube or a tank.

  As described above, the aluminum alloy brazing sheet according to the present invention has high strength after brazing. This brazing sheet is excellent in brazing properties such as fin joint ratio and erosion resistance. Further, excellent corrosion resistance can be achieved by using a brazing material or a sacrificial anode material having appropriate components, or using them simultaneously. The aluminum alloy brazing sheet according to the present invention is suitably used particularly as a tube material for a heat exchanger for transportation equipment because of the light weight and high thermal conductivity characteristics as well as the above characteristics.

The figure which showed typically the temperature chart at the time of brazing addition heat. The figure of the test piece for evaluation of brazing nature in this embodiment. The figure of the test core for the constant strain high temperature fatigue test in the heat exchanger in this embodiment.

  Hereinafter, the inventive examples and test Nos. The present invention will be described in more detail based on the above. The core material alloy having the alloy composition shown in Table 1, the brazing alloy having the alloy composition shown in Table 2, and the sacrificial anode material alloy having the alloy composition shown in Table 3 were cast by DC casting, respectively, and both sides were faced. Finished. The core alloy is not homogenized.

  Using these alloys, one side of the core alloy is combined with the brazing alloy shown in Table 2 as “Skin 1”, and the other side is combined with the brazing alloy shown in Table 2 as “Skin 2”. Three sacrificial anode alloys were combined. There are also two-layer materials that are not combined with the skin material 2. Then, these laminated materials were subjected to a heating step and a clad hot rolling step to produce a two-layer or three-layer clad material having a thickness of 3.5 mm. Table 4 shows the conditions of the heating process and the hot clad rolling process. Table 5 shows the configuration of the clad material (combination of core material, skin material 1 and skin material 2).

  About each produced clad material, the intermediate annealing hold | maintained at 400 degreeC for 5 hours, and the final cold rolling were performed, and the brazing sheet sample of 0.5 mm of final board thickness of H1n refining was produced. The cold rolling rate after the intermediate annealing was 40% in all cases.

  Manufacturability is evaluated in the manufacturing process of this brazing sheet sample. In this evaluation, when no problem occurred and the sheet was rolled to a final thickness of 0.5 mm, the manufacturability was evaluated as “◯”. On the other hand, cracks in casting, melting of the brazing material in the heating process, excessive elongation of the sacrificial anode material in the clad hot rolling process, poor crimping between the core material and the sacrificial anode material, and cracks during cold rolling occur, resulting in a brazing sheet sample. When it was not possible to manufacture, the productivity was evaluated as “x”. Table 5 also shows the evaluation results.

  The produced brazing sheet sample was subjected to the following evaluation tests. For each evaluation test, the brazing conditions in the evaluation items after brazing were selected from the combinations shown in Table 6. The conditions for artificial aging treatment performed after brazing were selected from the combinations shown in Table 7. The artificial aging treatment was started within 10 minutes after brazing.

(Measurement of area and number density of compound)
The core material portion of each brazing sheet sample was examined by polishing the L-LT surface and performing observation with a scanning transmission electron microscope (STEM). At this time, the film thickness of the observation part was measured using an electron spectrometer (EELS), and STEM observation was performed only at a position where the film thickness was 0.1 to 0.15 μm, so that a field of view of 10 μm × 10 μm was obtained for each sample. The average area and number density of the compound having an area of 0.1 μm ² or more and containing Mg were examined by image analysis in each visual field. Whether or not the compound contains Mg was identified by comparing the same field of view with the result of element mapping using an energy dispersive X-ray analyzer (EDS).

(Evaluation of creep resistance after brazing)
The artificial aging treatment selected from Table 8 was applied to the brazing sheet sample that had been heated corresponding to brazing under the conditions selected from Table 7. This sample was subjected to a creep test in accordance with JIS Z2271 under conditions of a temperature of 150 ° C. and a stress of 110 MPa. From the obtained results, the time required from the start of the creep test to the break was measured. As a result, a case where the time from the start of the test to breakage is 100 hours or more and less than 300 hours is determined to be acceptable (O), and a case where the time is less than 100 hours is determined to be unacceptable (x), and no breakage occurs until 300 hours. The case was excellent (◎).

(Evaluation of brazing)
The surface to be the test surface of the brazing sheet sample was masked, and the skin material on the reverse surface was removed by dipping in a 50 ° C. NaOH solution. Then, 3003 alloy was corrugated and fins having 20 ridges were placed on the brazing material surface of the brazing sheet sample and combined as shown in FIG. That is, there are 40 points of contact between the brazing sheet sample and the fins. This was immersed in a 5% fluoride flux aqueous solution and subjected to brazing addition heat at 600 ° C. for 3 minutes. The fins of this sample were peeled off, and the number of fillets formed in the contact between the brazing sheet sample and the fins was determined as N, and the joining rate (%) was determined as N / 40. When the joining rate is 95% or more and the core material of the brazing sheet sample or the 3003 alloy fin material is not melted, the brazing property is passed (O), and the fin joining rate is less than 95% or When melting occurred in the core material of the brazing sheet sample or the 3003 alloy fin material, the brazing property was determined to be rejected (x). In this evaluation test, when the brazing material was clad on both surfaces, only the skin material 1 was used as the test surface. Further, when the sacrificial anode material was clad on the skin material 2 or when the skin material 2 was not clad, the skin material 2 was not used as a test surface.

(Measurement of corrosion depth)
The brazing sheet sample was heated corresponding to brazing under the conditions selected from Table 7, and then subjected to artificial aging treatment selected from Table 8, cut into 50 mm × 50 mm, and the opposite side of the test surface was masked with resin. In this evaluation test, the test surface is the brazing material surface for the sample in which Zn is added to the brazing material, and the sacrificial anode material surface is the test surface for the sample in which the sacrificial anode material is clad. Evaluation of corrosion resistance was not performed on the samples that did not correspond anyway. When the test surface is a brazing material, it is subjected to the SWAAT test based on ASTM-G85, and the one that does not cause corrosion penetration in 500 hours is accepted (O), and the one that causes corrosion penetration is rejected (× ). In the case where the test surface is a sacrificial material, the cycle immersion is performed in one cycle of 8 hours in 88 ° C. high-temperature water containing Cl ⁻ : 500 ppm, SO ₄ ²⁻ : 100 ppm, Cu ²⁺ : 10 ppm, and standing at room temperature for 16 hours. The test was conducted for 3 months, and the case where no corrosion penetration occurred was determined to be acceptable (◯), and the case where the corrosion occurred was determined to be unacceptable (x).

(Constant strain high temperature fatigue test in heat exchanger)
Each manufactured brazing sheet was formed into a flat tube shape by electric sewing. Meanwhile, 3003 alloy fin material was corrugated. Then, as shown in FIG. 3, three flat tubes 1, two corrugated fins 2, and two 3003 alloy plates 3 having a thickness of 2 mm were combined. Here, the length of the surfaces of the two 3003 alloy plate members 3 was set to 100 mm. This was dipped in a 5% fluoride flux aqueous solution, dried at 200 ° C., and subjected to Norolock brazing under the conditions selected from Table 7 to prepare a test core 4.

The test core 4 was subjected to artificial aging treatment selected from Table 8, and two 3003 alloy plates 3 each having a thickness of 10 mm were sandwiched between upper and lower chucks of a high-temperature fatigue tester. In addition, the heating method at the time of the test was performed by covering the whole test piece with a thermostat. As test conditions, the frequency was 20 Hz, the minimum strain was 0, and the test temperature and the maximum strain were the same as shown in Table 9. The strain was calculated as L ÷ 100 with respect to the input displacement L. The case where the number of repetitions from the start of the test until the generated load reaches 50% of the maximum due to the breakage of the tube is 10 ⁵ times or more and less than 10 ⁶ times is accepted (◯), and the case where it is less than 10 ⁵ times is rejected (×) ) And the case where the tube did not break after 10 ⁶ times was evaluated as excellent (◎).

  The above evaluation results are shown in Tables 8 and 9. In addition, since the sample was not able to be manufactured for those having the productivity “x” in Table 6, the evaluation could not be performed.

  Hereinafter, the evaluation results of each evaluation test will be described in consideration of the configuration of the brazing sheet (core material, brazing material, sacrificial anode material). Moreover, the examination result regarding the brazing conditions of the brazing sheet and the artificial aging treatment conditions will be described.

(A) About composition of core material Test No. which is an example of the present invention. 1 to 10 satisfy the conditions defined in the present invention for the composition of the core material, and the productivity, area and number density of the compound, creep resistance after brazing, brazing, corrosion depth, in heat exchanger Both constant strain and high temperature fatigue passed.

  On the other hand, test no. Since 11-15 did not satisfy | fill the conditions prescribed | regulated by this invention in an essential structural element, either creep resistance or brazing property was disqualified as follows.

Test No. In No. 11, since the Si component of the core material was too small, the creep resistance after brazing was unacceptable.
Test No. In No. 12, since the Mg component of the core material was too small, the creep resistance after brazing was not acceptable.
Test No. In No. 13, since there was too much Si component of a core material, the brazing sheet core material melt | dissolved at the time of brazing, and brazing property was disqualified.
Test No. In No. 14, since there was too much Mg component of a core material, the unbonding of the fin occurred at the time of brazing, and brazing property was disqualified.
Test No. In No. 15, since there was too much Fe component of a core material, the corrosion of the wax to a core material occurred at the time of brazing, and brazing property was unsuccessful.

  As for the optional additive element of the core material, the test No. 16 to 18 do not satisfy the conditions defined in the present invention. Either the creep resistance or the brazing property failed in the following points.

Test No. In No. 16, since there were too many Cr, Zr, Ti, and V components of the core material, cracks occurred during rolling, and a brazing sheet could not be produced.
Test No. In No. 17, since there was too much Mn component of a core material, a crack generate | occur | produced during rolling and the brazing sheet could not be manufactured.
Test No. In No. 18, since there was too much Cu component of a core material, a crack occurred at the time of casting, and a brazing sheet could not be manufactured.

(B) About composition of brazing filler metal As described above, test No. which is an example of the present invention. Since 1-10 satisfy | filled the conditions prescribed | regulated by this invention also about the composition of a brazing material, each evaluation result was favorable. In addition, the inventive examples 5 and 6 in which Zn was added to the brazing material were also excellent in the corrosion depth of the brazing material surface. In contrast, test no. Nos. 19, 20 and 22 failed in terms of manufacturability and brazing from the viewpoint of the essential constituent elements of the brazing material in the following points.

Test No. In No. 19, since the Si component of the brazing material was too small, unbonding with the fin occurred, and the brazing property was unacceptable.
Test No. In No. 20, since there was too much Si component of the brazing material, the fin melted and the brazing property was unacceptable.
Test No. In No. 22, since there was too much Fe component of a brazing material, a crack occurred during rolling and a brazing sheet could not be manufactured.

  In addition, Test No. Nos. 21 and 23 to 27 failed in terms of manufacturability, brazing, and corrosion resistance in terms of the following points from the viewpoint of an optional additive element of the brazing material.

Test No. In No. 21, since there was too much Cu component of a brazing material, a crack occurred at the time of casting, and a brazing sheet could not be manufactured.
Test No. In No. 23, since there were too many Cr, Zr, Ti, and V components of the brazing material, cracks occurred during rolling, and a brazing sheet could not be produced.
Test No. In No. 24, since there was too much Mn component in the brazing material, cracks occurred during rolling, and a brazing sheet could not be produced.
Test No. In No. 25, since there were too many Na and Sr components of the brazing material, unbonding with the fin occurred, and the brazing property was unacceptable.
Test No. In No. 26, since there was too much Zn component of a brazing material, corrosion resistance was disqualified.
Test No. In No. 27, since the Zn component of the brazing material was too small, the corrosion resistance was unacceptable.

(C) About the composition of the sacrificial anode material,
The brazing sheet according to the present invention can include a sacrificial anode material as necessary. Test No. which is an example of the present invention. 1 to 10 were provided with a sacrificial anode material having a suitable composition, and each evaluation result was good. On the other hand, test No. as a comparative example. As for 28-34, since the composition of the sacrificial anode material did not satisfy the conditions specified in the present invention, the productivity and corrosion resistance were rejected as follows.

Test No. In No. 28, since there was too much Si component of a sacrificial anode material, corrosion resistance failed.
Test No. In No. 29, since there were too many Fe components of a sacrificial anode material, a crack generate | occur | produced during rolling and the brazing sheet could not be manufactured.
Test No. In No. 30, since there were too many Cr, Zr, Ti, and V components of a sacrificial anode material, a crack occurred during rolling, and a brazing sheet could not be produced.
Test No. In No. 31, since there was too much Mn component of a sacrificial anode material, a crack generate | occur | produced during rolling and the brazing sheet could not be manufactured.
Test No. In No. 32, since the Zn component of the sacrificial anode material was too small, the corrosion resistance was unacceptable.
Test No. In No. 33, since there was too much Zn component of a sacrificial anode material, corrosion resistance was disqualified.
Test No. In No. 34, since the Mg component of the sacrificial anode material was too much, the core material and the sacrificial anode material could not be pressure-bonded during hot rolling, and a brazing sheet could not be produced.

(D) Metal structure of core material The present invention defines the metal structure of the core material before brazing. And this metal structure is expressed by making manufacturing conditions (material temperature in a heating process and a clad hot rolling process) appropriate. Test no. Nos. 1 to 10 and 35 to 41 are produced by producing materials having suitable compositions under suitable production conditions. Manufacturability, area and number density of compounds, creep resistance after brazing, brazing , Corrosion depth, and constant strain high temperature fatigue in the heat exchanger were all passed.

  On the other hand, test No. which is a comparative example. Nos. 42 to 46 were those in which the holding temperature of the heating process, the starting temperature of the clad hot rolling process and the like were not in the preferred ranges, so that the manufacturability was rejected or The area and number density of the contained compound deviated from the conditions specified in the present invention, and the strength was not acceptable.

Test No. In No. 42, since the holding temperature in the heating process was too high, the brazing material was melted and a brazing sheet could not be produced.
Test No. 43, since the holding temperature in the heating step and the temperature at the start of the clad hot rolling were too low, the area and number density of the compound containing Mg in the core material before brazing were too large, and the creep resistance and constant strain in the heat exchanger Fatigue was rejected.
Test No. In No. 44, since the temperature at the start of clad hot rolling was too low, the area and number density of the compound containing Mg and Si in the core material before brazing were too large, and the creep resistance and constant strain fatigue in the heat exchanger failed. Met.
Test No. In No. 45, since the time during which the material temperature was 300 to 480 ° C. was too long at the start of clad hot rolling, the area and number density of the compound containing Mg in the core material before brazing were too large, and creep resistance and heat exchange The constant strain fatigue in the vessel was unacceptable.
Test No. In No. 46, the temperature at the end of the hot rolling of the clad was too high, so the area and number density of the compound containing Mg in the core material before brazing were too large, and the creep resistance and constant strain fatigue in the heat exchanger were not acceptable. It was.

(E) About brazing conditions and artificial aging treatment conditions The brazing sheet according to the present invention can have good brazing properties by appropriate brazing conditions. In addition, the artificial aging treatment after brazing can be performed under preferable conditions, so that the creep resistance after brazing can be further increased. The examination results are shown in Table 10. The test of Table 10 used the same material as the above, and the evaluation method was also the same.

  Regarding the brazing conditions, the test No. 47-51 were excellent in brazing property and also obtained good results in terms of strength such as creep resistance. On the other hand, test no. In No. 54, since the reached temperature at the time of brazing was too low, unbonding with the fin occurred, and the brazing property was not acceptable. In addition, Test No. In No. 55, since the reached temperature at the time of brazing was too high, the brazing sheet core material and the fins were melted at the time of brazing, and the brazability was unacceptable. In addition, Test No. No. 52 was slightly inferior in creep resistance because the holding time at a material temperature of 580 ° C. or more exceeded 12 minutes. In addition, Test No. 53 was slightly inferior in creep resistance because the cooling rate to a material temperature of 300 ° C. was slightly slow. However, test no. 52 and 53 are in the acceptable range although creep resistance is slightly inferior.

  In addition, with regard to artificial aging treatment conditions, Test No. 56 to 61 were confirmed to have good creep resistance. On the other hand, test no. No. 62 had a short treatment time and a little inferior creep resistance. Test No. No. 63 had a long processing time and was slightly inferior in creep resistance. In addition, Test No. No. 64 had a low processing temperature and a little inferior creep resistance. Test No. No. 65 had a high processing temperature and a little inferior creep resistance. However, test no. 62-65 is in the pass range although the creep resistance is slightly inferior.

  The aluminum alloy brazing sheet according to the present invention has high creep resistance after brazing, and is excellent in brazing and corrosion resistance such as fin joint ratio and erosion resistance. In particular, since it is excellent in lightness and high thermal conductivity, it is particularly suitably used as a tube material for a heat exchanger for transportation equipment.

Claims (8)

In an aluminum alloy brazing sheet comprising a core material made of an aluminum alloy and a brazing material made of an Al-Si alloy clad on at least one surface of the core material,
The core material contains Si: 0.3 to 1.5 mass%, Fe: 0.05 to 1.0 mass%, Mg: 0.05 to 0.6 mass%, and an aluminum alloy composed of the balance Al and inevitable impurities And
The brazing filler metal is an aluminum alloy containing Si: 2.5 to 13.0 mass%, Fe 0.05 to 2.0 mass%, the balance being Al and inevitable impurities,
When the core material is an intermetallic compound containing Mg and has an area of 0.1 μm ² or more in an arbitrary cross section before brazing, the average area is 1 μm ² or less, and the number thereof A high-strength aluminum alloy brazing sheet having a density of 1 piece / μm ² or less.   The core material is further Mn: 0.05 to 2.0 mass%, Cu: 0.05 to 2.0 mass%, Ti: 0.05 to 0.3 mass%, Zr: 0.05 to 0.3 mass%, Cr The high-strength aluminum alloy brazing sheet according to claim 1, comprising at least one selected from the group consisting of: 0.05 to 0.3 mass% and V: 0.05 to 0.3 mass%.   The brazing material clad on at least one surface of the core material is further Zn: 0.3-8.0 mass%, Cu: 0.05-2.0 mass%, Mn: 0.05-2.0 mass%, Ti0. 05-0.3 mass%, Zr: 0.05-0.3 mass%, Cr: 0.05-0.3 mass%, V: 0.05-0.3 mass%, Na: 0.001-0.05% Sr: The high-strength aluminum alloy brazing sheet of Claim 1 or 2 containing 1 or more types selected from the group which consists of 0.001-0.05%. A brazing material is clad on one surface of the core material, and a sacrificial anode material made of an aluminum alloy is clad on the other surface of the core material,
The sacrificial anode material contains Zn: 0.3 to 8.0 mass%, Si: 0.05 to 1.5 mass%, Fe: 0.05 to 2.0 mass%, and is composed of the balance Al and inevitable impurities. The high-strength aluminum alloy brazing sheet according to any one of claims 1 to 3, which is an aluminum alloy.   Sacrificial anode material is further Mn: 0.05-2.0 mass%, Mg: 0.5-3.0 mass%, Ti: 0.05-0.3 mass%, Zr: 0.05-0.3 mass% The high-strength aluminum alloy brazing sheet according to claim 4, comprising at least one selected from the group consisting of Cr: 0.05 to 0.3 mass% and V: 0.05 to 0.3 mass%. A method for producing a high-strength aluminum alloy brazing sheet according to any one of claims 1 to 5,
Casting an aluminum alloy of a core material and a brazing material,
A mating step of combining a brazing material cast on at least one surface of the cast core material into a mating material;
A heating step of heating and holding the bonding material after the bonding step;
A clad hot rolling step of hot rolling the laminated material after the heating step;
A cold rolling step of cold rolling after the clad hot rolling;
Including an annealing step of performing annealing at least once during or after the cold rolling step,
In the heating step, the heating temperature is 480 to 550 ° C., the holding time after reaching the temperature is 0 to 10 hours,
In the clad hot rolling step, the temperature of the laminated material at the start of hot rolling is set to 480 to 550 ° C., and the time during which the temperature of the laminated material is 300 to 480 ° C. at the time of hot rolling of the clad is set to 30 minutes or less. The material temperature is set to 320 ° C. or lower.
A method for producing a high-strength aluminum alloy brazing sheet.   7. The high-strength aluminum alloy brazing according to claim 6, wherein in the joining step, a brazing material cast on one side of the cast core is combined, and a sacrificial anode material cast on the other side of the core is combined. Sheet manufacturing method. A heat exchanger using the high-strength aluminum alloy brazing sheet according to any one of claims 1 to 5 as a material for a flow path forming component,
In the cooling process at the time of brazing, the cooling rate until the heat exchanger is cooled to 300 degrees is set to 30 ° C./min or more,
After brazing, an artificial aging treatment is performed at a temperature of 160 to 180 ° C. for 1 minute to 10 hours,
Further, the maximum temperature of the flow path forming component when it is loaded on a transport device and traveling is 80 ° C. to 190 ° C., and strain of 0.35% or more is applied to the flow path forming component. Heat exchanger.

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