JP5543119B2 - Method for producing high heat resistant aluminum alloy brazing sheet - Google Patents

Description

The present invention relates to an aluminum alloy brazing sheet used for heat exchangers for automobiles and the like, in particular, an aluminum alloy having high heat resistance, which is suitably used as a high temperature compressed air or refrigerant passage component in a heat exchanger such as an intercooler. a method of manufacturing a brazing sheet.

  Aluminum alloys are light and have high thermal conductivity, and are therefore widely used in automotive heat exchangers, such as radiators, condensers, evaporators, heaters, intercoolers, and the like. The heat exchanger for automobiles is manufactured mainly by a brazing method, and in that case, it is usually brazed at a high temperature of about 600 ° C. using a brazing material of an Al—Si alloy.

  By the way, the heat exchanger made from aluminum alloy manufactured by brazing is comprised by the corrugated fin mainly responsible for heat dissipation, and the tube as a channel | path component for circulating air, cooling water, and a refrigerant | coolant. In such a heat exchanger, if the tube breaks and penetrates, there is a problem that leakage of air, cooling water, and refrigerant circulating inside occurs. On the other hand, in recent years, demands for reducing the weight of automobiles are increasing, and therefore, there is a strong demand for reducing the thickness of each member constituting a heat exchanger for automobiles. It is desired to realize about 6 mm or less.

  In order to achieve the improvement in product life and weight reduction of such a heat exchanger at the same time, an aluminum alloy brazing sheet having excellent strength after brazing is indispensable as a passage component member. Furthermore, recently, in order to satisfy exhaust gas regulations in the EU and the United States, high performance is required for turbochargers mounted on diesel engine vehicles. Accordingly, the pressure of the air compressed by the turbocharger tends to be higher than before, and the temperature of the compressed air also tends to be higher. Therefore, the operating temperature of the intercooler, which is a device that cools the air that has been compressed by the turbocharger, becomes higher than before, and therefore the brazing sheet that is a passage component member is also used after brazing. The demand for heat resistance is even stronger than before.

  Here, if the tube and the fin are sufficiently brazed, since the fin suppresses the deformation of the tube, even if a high pressure is applied for a long time at a high temperature as described above, it may exhibit a certain degree of durability. it can. However, in an intercooler used at a higher temperature and higher pressure than before, a tube material having higher creep resistance than before is required.

  Conventionally, as a tube material for an automotive intercooler, a tube material made of a three-layer brazing sheet in which a brazing material such as an Al-Si alloy is clad on both sides of a core material made of an Al-Mn alloy represented by JIS3003 alloy, etc. Has been widely used. However, the high temperature strength after brazing of the clad material using the JIS3003 alloy core material is only about 60 MPa at 200 ° C., for example, and is not a tube material for an intercooler used at recent high temperatures and high pressures. It was enough.

  By the way, as a proposal which improved the heat resistance of the brazing sheet using the core material which consists of an Al-Mn type alloy, the technique as shown to patent documents 1-3 is already known.

Among them, Patent Document 1 improves the heat resistance by increasing the alloy component of the core material than conventional materials and containing Mg, and performing hot rolling, intermediate annealing, and final annealing within a predetermined temperature range. An aluminum alloy brazing sheet is shown. Patent Document 2 discloses an aluminum alloy brazing sheet in which heat resistance is improved by using precipitation hardening with Mg ₂ Si by adding Mg to the core material and performing peak aging treatment after brazing. . Furthermore, in Patent Document 3, the aluminum alloy brazing sheet that defines the homogenization treatment conditions of the core material and makes the distribution before the hot rolling 500 ° C. or less to make the distribution of intermetallic compounds fine and improve the strength. It is shown.

  However, in these proposals of Patent Documents 1 to 3, the heating time before hot rolling, the time required for hot rolling, etc. are not clearly and strictly defined, and therefore are relatively coarse during these steps. The amount of Mn dissolved in the matrix phase of the core material aluminum, which is effective for improving heat resistance, may be reduced due to precipitation of intermetallic compounds, resulting in insufficient high-temperature strength after brazing. There is a risk that. Therefore, these proposed technologies still have insufficient heat resistance, and it has been difficult to reliably and stably obtain high-temperature strength that can withstand use at a high temperature of about 200 ° C.

Special table 2007-530794 gazette JP-T-2004-524442 JP-A-8-246117

This invention has been made against the background of the above circumstances, high temperature strength after brazing, etc. in order to satisfy the requirements for high heat resistance and thinning of aluminum alloy brazing sheets used as tube materials for automotive intercoolers, etc. It is a basic problem to provide a method for producing a brazing sheet having a high-temperature strength that can withstand use at a high temperature of about 200 ° C., which is difficult to achieve with the prior art. In the present invention, the aluminum alloy not only has excellent high-temperature strength after brazing as described above, but also has low brazing diffusion and good brazing properties as a brazing material. brazing sheet, in particular those which an object to provide a method for producing an aluminum alloy brazing sheet that can be suitably used as a fluid passage forming material of the automobile heat exchanger such as an intercooler (tubing).

  In order to solve the above-mentioned problems, the present inventors have conducted extensive experiments and examinations. As a result, the component composition of the core material made of the Al-Mn alloy in the aluminum alloy brazing sheet is appropriately adjusted, and particularly suitable amount. It has been found that the above-mentioned problems can be solved by adding Cu and adjusting the amount of Si and Fe appropriately and also adjusting the metal structure, particularly the dispersion state of intermetallic compounds. In addition, the inventors have found suitable conditions for producing an aluminum alloy brazing sheet having such a metal structure in the core material, particularly suitable conditions in hot clad rolling. And based on these, it came to make this invention.

Specifically, the invention of claim 1 is a method for producing an aluminum alloy brazing sheet formed by clad an Al—Si brazing material on one or both sides of a core material made of an aluminum alloy;
The aluminum alloy of the core material is Si 0.05% (mass%, hereinafter the same) or more and less than 0.3%, Fe0.05-0.4%, Cu0.3-1.2%, Mn0.8-1.8 1% or more selected from Ti0.05-0.3%, Zr0.05-0.3%, Cr0.05-0.3%, V0.05-0.3% The balance is made of Al and inevitable impurities, and the distribution density of the intermetallic compound of 0.1 μm or more and less than 0.3 μm in the plate cross section in the thickness direction is 10 / μm ² as the metal structure of the core part. In producing a high heat-resistant aluminum alloy brazing sheet having a distribution density of intermetallic compounds of 0.3 μm or more and 0.5 pieces / μm ² or less ,
An Al-Si alloy brazing material is superposed on one side or both sides of the core material, and these are heated and hot-rolled to form a clad material, and the resulting clad material is cooled. A cold rolling process for cold rolling, and an intermediate annealing process for performing intermediate annealing at least once in the middle of cold rolling;
In the hot clad rolling step, the thickness of the overlapped material before hot clad rolling is 250 mm or more and 800 mm or less, and heating before hot clad rolling is performed at a temperature in the range of 400 ° C. or more and 500 ° C. or less for 10 hours or less. In addition, the time required for the plate thickness reduction amount to reach 50 mm after starting hot clad rolling is controlled to 5 minutes or less, and the material temperature when the plate thickness reduction amount reaches 50 mm is set to 400 ° C. The temperature is controlled to 450 ° C. or less, and the time required for the plate thickness to reach 20 mm after the plate thickness reduction amount reaches 50 mm is controlled to 10 minutes or less, and the material temperature when the plate thickness reaches 20 mm. Is controlled between 300 ° C. and 400 ° C., and the time required from the start of hot clad rolling to the end of hot clad rolling is controlled to 40 minutes or less. Also the in the intermediate annealing step is characterized in that performing the intermediate annealing at a temperature within the range of 250 ° C. to 400 ° C. using a furnace of a batch type.

The invention of claim 2 is characterized in that an alloy containing 0.05 to 0.5% of Mg is used in addition to each of the component elements as the aluminum alloy of the recording material.

Furthermore, the invention of claim 3 is a method for producing an aluminum alloy brazing sheet obtained by clad an Al—Si brazing material on one or both sides of a core material made of an aluminum alloy;
The aluminum alloy of the core material is Si 0.05% (mass%, hereinafter the same) or more and less than 0.3%, Fe0.05-0.4%, Cu0.3-1.2%, Mn0.8-1.8 1% or more selected from Ti0.05-0.3%, Zr0.05-0.3%, Cr0.05-0.3%, V0.05-0.3% The balance is made of Al and inevitable impurities, and the distribution density of the intermetallic compound of 0.1 μm or more and less than 0.3 μm in the plate cross section in the thickness direction is 10 / μm ² as the metal structure of the core part. In producing a high heat-resistant aluminum alloy brazing sheet having a distribution density of intermetallic compounds of 0.3 μm or more and 0.5 pieces / μm ² or less,
An Al-Si alloy brazing material is superposed on one side or both sides of the core material, and these are heated and hot-rolled to form a clad material, and the resulting clad material is cooled. A cold rolling process for cold rolling, and an intermediate annealing process for performing intermediate annealing at least once in the middle of cold rolling;
In the hot clad rolling step, the thickness of the overlapped material before hot clad rolling is 250 mm or more and 800 mm or less, and heating before hot clad rolling is performed at a temperature in the range of 400 ° C. or more and 500 ° C. or less for 10 hours or less. The time required for the plate thickness reduction amount to reach 50 mm after the start of hot clad rolling is controlled to 5 minutes or less, and the material temperature when the plate thickness reduction amount reaches 50 mm is 400 ° C. or more. The time required until the plate thickness reaches 20 mm after the plate thickness reduction amount reaches 50 mm is controlled to 450 ° C. or less, and the material temperature at the time when the plate thickness reaches 20 mm is controlled. The temperature is controlled between 300 ° C. and 400 ° C., and the time required from the start of hot clad rolling to the end of hot clad rolling is controlled to 40 minutes or less. In serial intermediate annealing step, and is characterized in that performing the intermediate annealing at a temperature in the range of 380 to 550 ° C. using a furnace continuously.

Further, the invention of claim 4 is the method for producing a high heat-resistant aluminum alloy brazing sheet according to claim 3 , wherein, in addition to the component elements, Mg 0.05 to 0.5% as the aluminum alloy of the core material An alloy containing is used .

On the other hand, the invention according to claim 5 is the method for producing a high heat-resistant aluminum alloy brazing sheet according to any one of claims 1 to 4 ; after the cold rolling step, 200 to 400 ° C. A softening annealing step of heating to a temperature within the range is performed .

The invention of claim 6 is a method for producing an aluminum alloy brazing sheet comprising an aluminum alloy brazing material clad on one or both sides of a core material made of an aluminum alloy;
The aluminum alloy of the core material is Si 0.05% (mass%, hereinafter the same) or more and less than 0.3%, Fe0.05-0.4%, Cu0.3-1.2%, Mn0.8-1.8 1% or more selected from Ti0.05-0.3%, Zr0.05-0.3%, Cr0.05-0.3%, V0.05-0.3% The balance is made of Al and inevitable impurities, and the distribution density of the intermetallic compound of 0.1 μm or more and less than 0.3 μm in the plate cross section in the thickness direction is 10 / μm ² as the metal structure of the core part. In producing a high heat-resistant aluminum alloy brazing sheet having a distribution density of intermetallic compounds of 0.3 μm or more and 0.5 pieces / μm ² or less,
A hot clad rolling process in which an Al-Si alloy brazing material is superposed on one side or both sides of the core material and heated and hot rolled to form a clad material, and the resulting clad material is cold rolled. A cold rolling step, and a softening annealing step performed after the cold rolling step,
In the hot clad rolling step, the thickness of the overlapped material before hot clad rolling is 250 mm or more and 800 mm or less, and heating before hot clad rolling is performed at a temperature in the range of 400 ° C. or more and 500 ° C. or less for 10 hours or less. The time required for the plate thickness reduction amount to reach 50 mm after the start of hot clad rolling is controlled to 5 minutes or less, and the material temperature when the plate thickness reduction amount reaches 50 mm is 400 ° C. or more. The time required for the plate thickness to reach 20 mm after the plate thickness reduction amount reaches 50 mm is controlled to 450 ° C. or less, and the material temperature when the plate thickness reaches 20 mm is controlled. The temperature is controlled between 300 ° C. and 400 ° C., and the time required from the start of hot clad rolling to the end of hot clad rolling is controlled to 40 minutes or less. In the softening annealing step, is characterized in that the heating temperature in the range of 200 to 400 ° C..

Furthermore, the invention of claim 7 is the method for producing a high heat-resistant aluminum alloy brazing sheet according to claim 6 ; As the aluminum alloy of the core material, in addition to each of the component elements, Mg 0.05 to 0.5% is further added. It is characterized by using an alloy containing it .

And the invention of claim 8 is the method for producing a high heat-resistant aluminum alloy brazing sheet according to any one of claims 1 to 7 ;
An Al—Si alloy brazing material is superposed on one surface of the core material, and the other surface of the core material contains Zn 1.0 to 6.0%, Fe 0.05 to 0.4%, and the balance is An Al—Zn-based aluminum alloy sacrificial anode material made of Al and inevitable impurities is superposed, heated in this state, and subjected to hot clad rolling .

The invention of claim 9 is the method for producing a high heat-resistant aluminum alloy brazing sheet according to claim 8 ; As the Al—Zn-based aluminum alloy sacrificial anode material, in addition to the component elements, Si 1.0% Hereinafter, an alloy containing one or more selected from Mn 1.8% or less, Ti 0.02 to 0.3%, and V 0.02 to 0.3% is used .

According to the method for producing an aluminum alloy brazing sheet of the present invention , even if the thickness is reduced to about 0.6 mm or less, not only is it excellent in brazing properties such as fin joint rate and erosion resistance, but also after brazing. As a thin brazing sheet for use at high temperatures and high pressures, such as automotive heat exchangers, especially intercooler tubes, etc. An extremely excellent brazing sheet can actually be manufactured reliably and stably , and the weight of the heat exchanger can be reduced and its life can be extended at the same time.

FIG. 1 is a schematic perspective view showing a test core used for repeated pressure resistance evaluation in Examples. FIG. 2 is a schematic cross-sectional view showing a situation in which a repeated pressure resistance test is performed using the test core shown in FIG.

Aluminum production method of alloy brazing sheet of the present invention, its preferred embodiments, described in detail below.

First, each alloy used for the core material, the brazing material, and the sacrificial anode material constituting the aluminum alloy brazing sheet to be obtained by the manufacturing method of the present invention will be described.

  The core aluminum alloy contains Si 0.05% or more and less than 0.3%, Fe 0.05 to 0.4%, Cu 0.3 to 1.2%, Mn 0.8 to 1.8%, and Ti0 0.05 to 0.3%, Zr 0.05 to 0.3%, Cr 0.05 to 0.3%, V 0.05 to 0.3%, one or more selected from among, the balance is Al And what consists of an unavoidable impurity is used. The reasons for limiting the components of such a core material alloy are as follows.

[Heart]
Si:
Si is an element inevitably contained in a normal aluminum alloy, but since this Si forms an Al—Mn—Si based intermetallic compound together with Mn, if the content is large, the amount of dissolved Mn is large. As a result, the effect of solid solution strengthening by solid solution Mn cannot be sufficiently obtained. In particular, if the Si content is 0.3% or more, the solid solution Mn content decreases and the high-temperature strength decreases. On the other hand, in order to make the amount of Si less than 0.05%, it is necessary to use a high purity aluminum ingot, which causes an increase in cost. Therefore, the Si content of the core material is set in the range of 0.05% or more and less than 0.3%.

Fe:
Fe easily forms an intermetallic compound of a size that can become a recrystallization nucleus, and if the content of Fe is large, the crystal grain size after brazing becomes fine and wax diffusion tends to occur. Less is desirable. However, if the Fe content is less than 0.05%, high-purity aluminum ingots must be used, leading to an increase in cost. On the other hand, if the Fe content exceeds 0.4%, the crystal grain size after brazing is fine. As a result, wax diffusion may occur. Therefore, the amount of Fe is set in the range of 0.05 to 0.4%. Preferably, the Fe content is in the range of 0.1 to 0.2%.

Cu:
Cu contributes to the improvement of high temperature strength by solid solution strengthening. If the Cu content is less than 0.3%, the effect due to the addition of Cu is small. On the other hand, if the Cu content exceeds 1.2%, the possibility of cracking during casting increases. Was in the range of 0.3-1.2%. Preferably, the Cu amount is in the range of 0.5 to 1.0%.

Mn:
Mn contributes to the improvement of high temperature strength by solid solution strengthening. If the Mn content is less than 0.8%, the effect of adding Mn is small. On the other hand, if the Mn content exceeds 1.8%, a giant intermetallic compound is likely to be produced during casting, and the plastic workability is lowered. . Therefore, the amount of Mn of the core material is set in the range of 0.8 to 1.8%. The Mn content is preferably in the range of 1.0 to 1.6%.

  Furthermore, as a component element of the core material of the brazing sheet of the present invention, one or more selected from Ti, Zr, Cr, and V are added. These elements are all elements that contribute to the improvement of the high-temperature strength, and will be described next.

Ti:
Ti is an element that improves the high-temperature strength by solid solution strengthening, and is selectively added within a range of 0.05 to 0.3%. If the amount of Ti is less than 0.05%, the effect cannot be obtained. On the other hand, if it exceeds 0.3%, it becomes easy to form a giant intermetallic compound, and the plastic workability is lowered. A more preferable range of Ti addition is 0.1 to 0.2%. In general aluminum alloys, a minute amount (usually 0.005 to 0.05%) of Ti may be added to refine the structure of the ingot. Usually 0.001 to 0.01%) of B may be added, and the brazing sheet core material of the present invention is allowed to add Ti and B to that extent for the above purpose.

Zr:
Zr is an element that improves the high-temperature strength by solid solution strengthening, and addition of Zr precipitates an Al-Zr-based intermetallic compound and contributes to coarsening of the crystal grains after brazing. It can be added within a range of ˜0.3%. If the amount of Zr is less than 0.05%, the effect cannot be obtained. On the other hand, if the amount of Zr exceeds 0.3%, a giant intermetallic compound is likely to be formed, and the plastic workability is lowered. A more preferable range of the addition amount of Zr is 0.1 to 0.2%.

Cr:
Cr also improves the high-temperature strength by solid solution strengthening, and Al—Cr-based intermetallic compounds are precipitated by addition of Cr, which contributes to coarsening of crystal grains after brazing. It can be added within a range of 3%. If the Cr content is less than 0.05%, the effect cannot be obtained. On the other hand, if the Cr content exceeds 0.3%, a giant intermetallic compound is likely to be formed, and the plastic workability is lowered. A more preferable range of Cr addition is 0.1 to 0.2%.

V:
V is also an element that improves the high-temperature strength by solid solution strengthening, and can be added in the range of 0.05 to 0.3%. If the V addition amount is less than 0.05%, the effect cannot be obtained. On the other hand, if the V addition amount exceeds 0.3%, a huge intermetallic compound is not easily formed, and the plastic workability is lowered. A more preferable range of V is 0.1 to 0.2%.

  As a component of the core material of the aluminum alloy brazing sheet of the present invention, Al and unavoidable impurities may be basically used in addition to the above elements. However, as defined in claim 2, Mg is further reduced to 0. You may add in 0.05 to 0.5% of range.

That is, Mg is an element that improves high-temperature strength by reacting with Si diffused from the brazing material during brazing to precipitate Mg ₂ Si, and if necessary for further improvement of high-temperature strength. It may be added. Here, if the amount of Mg added is less than 0.05%, the effect is small, while if it exceeds 0.5%, brazing becomes difficult, so the amount added is in the range of 0.05 to 0.5%. Within. In addition, Preferably, Mg addition amount shall be in the range of 0.15-0.4%.

[Brazing material]
The brazing material is clad on one side or both sides of the core material in the aluminum alloy brazing sheet of the present invention. As this brazing material, Al-Si alloy brazing material generally used for aluminum alloy brazing sheets is conventionally used. Can be used, and is not particularly limited. For example, JIS 4343, 4045, 4047 alloy (Al-7 to 13 mass% Si) and the like are preferable.

[Sacrificial anode material]
In the aluminum alloy brazing sheet of the present invention, the brazing material is clad on one side or both sides of the core material as described above, but in the case where high corrosion resistance is required as the use environment of the heat exchanger, in claim 3 As specified, the sacrificial anode material may be clad on one side of the core material (that is, the surface on the side where the brazing material is clad only on one side of the core material and the brazing material is not clad). . As a sacrificial anode material in that case, an Al—Zn alloy containing 1.0 to 6.0% of Zn and 0.05 to 0.4% of Fe and the balance of Al and inevitable impurities is used. The reasons for limiting the components of the sacrificial anode material are as follows.

Zn:
When Zn is added to Al, its potential can be reduced. Therefore, by clad the alloy to which Zn is added on one side of the core material, the sacrificial anode effect can be exhibited and the corrosion resistance can be improved. . Here, if the Zn content is less than 1.0%, the effect is not sufficient. On the other hand, if the Zn content exceeds 6.0%, the corrosion rate increases and the sacrificial anode material disappears early, and the corrosion resistance is reversed. Therefore, the amount of Zn in the sacrificial anode material is set in the range of 1.0 to 6.0%. Even within this range, Zn is particularly preferably within the range of 2.0 to 5.0%.

Fe:
Fe easily forms an intermetallic compound of a size that can become a recrystallization nucleus, and if the content of Fe is large, the crystal grain size after brazing becomes fine and wax diffusion tends to occur. Less is desirable. However, if the amount of Fe is less than 0.05%, high-purity aluminum ingots must be used, resulting in high costs. On the other hand, if the amount of Fe exceeds 0.4%, the crystal grain size after brazing is fine. As a result, wax diffusion may occur. Therefore, the amount of Fe is set in the range of 0.05 to 0.4%. Preferably, the Fe content is in the range of 0.1 to 0.2%.

  Components other than Zn and Fe in the Al—Zn alloy used as the sacrificial anode material may be basically Al and inevitable impurities, but are mainly defined in claim 4 for improving high-temperature strength. As described above, one or more selected from Si, Mn, Ti, and V may be added. The reason for the addition of these selectively added elements in the sacrificial anode material will be described next.

Si:
Si forms an Al-Fe-Mn-Si compound together with Fe and Mn and contributes to improving high temperature strength by dispersion strengthening, and Si dissolved in the matrix improves high temperature strength by solid solution strengthening. . Further, if Si is added, it reacts with Mg diffusing from the core material during brazing to form an Mg ₂ Si compound, thereby contributing to improvement in high temperature strength. Here, if the amount of Si in the sacrificial anode material exceeds 1.0%, the melting point of the sacrificial anode material is lowered, and there is a high possibility that melting occurs during brazing addition heat, and Si is the potential of the sacrificial anode material. If the Si content exceeds 1.0%, the sacrificial anode effect is hindered and the corrosion resistance is reduced. Therefore, the amount of Si added is set to 1.0% or less. A more preferable amount of Si is 0.8% or less.

Mn:
Mn is an element that improves high-temperature strength and corrosion resistance, and is added within a range of 1.8% or less. If the amount of Mn exceeds 1.8%, a giant intermetallic compound is likely to be produced during casting, and the plastic workability is lowered. Further, since Mn is an element that makes the potential of the sacrificial anode material noble, if Mn is added in excess of 1.8%, the sacrificial anode effect is hindered and the corrosion resistance is lowered. A more preferable amount of Mn is 1.5% or less.

Ti:
Ti is an element that improves the high-temperature strength by solid solution strengthening and improves the corrosion resistance, and is added within a range of 0.02 to 0.3%. If the Ti content exceeds 0.3%, a huge intermetallic compound is likely to be produced, and the plastic workability is lowered. A more preferable range of Ti addition is 0.1 to 0.2%. As already described for the core material, in a normal aluminum alloy, a small amount (usually 0.005 to 0.05%) of Ti may be added for refining the structure at the time of casting, and for the same purpose, A trace amount (usually 0.001 to 0.01%) of B may be added together with Ti, and the Al—Zn-based alloy of the sacrificial anode material in the brazing sheet of the present invention is also Ti for this purpose. , B is acceptable.

V:
V improves the high temperature strength by solid solution strengthening and is effective in improving the corrosion resistance, and is added within a range of 0.02 to 0.3%. If the amount of V is less than 0.02%, the effect cannot be obtained. On the other hand, if the amount of V exceeds 0.3%, a giant intermetallic compound is likely to be generated, and the plastic workability is lowered. A more preferable range of V is 0.1 to 0.2%.

In the aluminum alloy brazing sheet of the present invention, not only the component composition of each alloy used as the core material, brazing material, and sacrificial anode material is adjusted as described above, but also as the metallographic condition of the core material part, the final cold The dispersion state of the intermetallic compound in the product plate after rolling (before brazing addition heat) is important. That is, as the metal structure of the core material portion after the final cold rolling of the brazing sheet, the distribution density of intermetallic compounds having a size of 0.1 μm or more and less than 0.3 μm in the cross section in the thickness direction is 10 / μm ² or less, Preferably, it is 5 pieces / μm ² or less, and the distribution density of the intermetallic compound having a size of 0.3 μm or more needs to be 0.5 pieces / μm ² or less. In addition, all the sizes of the intermetallic compound prescribed | regulated here shall mean a circle equivalent diameter.

  The reason for determining the size and density of the intermetallic compound in the core part in this way is as follows.

  In the core material of the aluminum alloy brazing sheet of the present invention, basically, the high-temperature strength after the brazing heat is improved mainly by solid solution strengthening with a solid solution element (mainly solid solution Mn). Here, at the stage of the brazing sheet product plate before brazing addition heat, if the core material part contains a large amount of intermetallic compound, the intermetallic compound that could not be completely re-dissolved during brazing addition heat becomes the core. Al-Mn-Si-based compounds are precipitated, and as a result, the amount of solid solution elements mainly composed of solid solution Mn is reduced in the state after the brazing addition heat, and the effect of improving the high temperature strength by solid solution strengthening is sufficient. It can no longer be obtained. Therefore, it is desirable that the number of intermetallic compounds present in the core material before the heat of brazing is small and the size thereof is small. And as a result of detailed experiments and examinations by the present inventors, it is necessary that the distribution density of intermetallic compounds in the core material of the product plate (before brazing heat addition) be regulated as described above, in that case For the first time, it has been found that the amount of solid solution elements such as solid solution Mn after brazing heat is sufficiently secured, and that the effect of improving the high temperature strength by solid solution strengthening can be sufficiently obtained. It was decided. Here, the brazing conditions are not particularly limited, and are usually performed by heating to about 600 ° C. and then air-cooling. Here, the performance such as high-temperature strength after brazing addition heat is as follows: It shall mean the performance after brazing under normal conditions.

  Furthermore, the reasons for limiting the distribution conditions of the intermetallic compound as described above will be described in detail.

An aluminum alloy brazing sheet after final cold rolling (that is, a brazing sheet before brazing addition heat) in order to sufficiently secure solid solution strengthening by sufficiently securing the amount of solid solution elements mainly composed of Mn after brazing addition heat. ), The density of intermetallic compounds of 0.1 μm or more and less than 0.3 μm is 10 / μm ² or less, more preferably 5 / μm ² or less, and the distribution density of intermetallic compounds of 0.3 μm or more. Is 0.5 pieces / μm ² or less. In the core material part of the aluminum alloy brazing sheet having such a metal structure, even in the stage after being subjected to brazing addition heat, the aluminum matrix phase of the core material contains a large amount of Mn and Si in a solid solution state. Even after brazing heat, the effect of improving the high temperature strength by sufficient solid solution strengthening can be exhibited. Further, not only Mn and Si but also solid solution strengthening by selectively added Ti, Zr, Cr, and V contributes to the improvement of the high temperature strength. If it is solid-solved in the aluminum alloy matrix of the core material at the stage after brazing, it is possible to further enhance solid solution strengthening. On the other hand, the core part of the aluminum alloy brazing sheet after the final rolling contains more than 10 / μm ² of intermetallic compounds of 0.1 μm or more and less than 0.3 μm, and the intermetallic compound of 0.3 μm or more is 0.8. When the amount is more than 5 / μm ^2, it is not possible to secure a sufficient amount of solid solution such as Mn after brazing addition heat, and the effect of solid solution strengthening cannot be expected.

  Here, the density and size of the intermetallic compound are determined by polishing the L-LT surface of the core material portion of the brazing sheet after the final cold rolling by polishing, and observing the core material portion with a transmission electron microscope (TEM). Shall be investigated. In this TEM observation, the film thickness of the observation part is measured from the equal-thickness interference fringes, the TEM observation is performed only at the position where the film thickness is 0.1 to 0.3 μm, and the TEM photograph is image-analyzed. The density of the intermetallic compound shall be determined.

In the core material of the aluminum alloy brazing sheet according to claim 2, not only the effect of improving the high temperature strength by solid solution strengthening as described above, but also by age hardening by adding Mg to precipitate Mg ₂ Si, it is possible to further improve the strength. The high temperature strength is improved. Here, when Mg is added to the core material, the brazing property is lowered, but the high temperature strength is sufficiently high, so that it is possible to show sufficient durability against a long-time pressure load.

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

In the aluminum alloy brazing sheet of this invention, in order to obtain a sufficient amount of solid solution elements (mainly solid solution Mn amount) after the brazing heat and exert a sufficient high temperature strength improving effect, as described above, the final cooling is performed. After hot rolling (before brazing heat addition), the density of intermetallic compounds of 0.1 μm or more and less than 0.3 μm in the core part is 10 / μm ² or less, more preferably 50 / μm ² or less, and 0.3 μm It is necessary to regulate the density of the above intermetallic compounds to be 0.5 pieces / μm ² or less. In order to regulate excessive precipitation of intermetallic compounds in this way, It is necessary to control the generated heat within an appropriate range, and in particular, precise control of temperature and time at each stage of hot rolling is extremely important.

  The aluminum alloy brazing sheet of the present invention is basically formed by cladding an Al-Si brazing material (or an Al-Si brazing material and a sacrificial anode material) on one or both sides of a core material made of an alloy having the above-mentioned composition. Manufactured by. First, the manufacturing method of the core material will be described.

  As the core material, each of the aluminum alloys having the above-described composition is melted and cast according to a conventional method such as a DC casting method. At the time of casting, in order to increase the amount of Mn dissolved in the ingot, the cooling rate after casting is preferably set to 1.5 ° C./s or more. The obtained core material ingot is chamfered and finished as necessary, and then subjected to hot clad rolling, but before the hot clad rolling, the core material ingot is not homogenized. Or ingot heating at a temperature of 550 ° C. or higher. In the case where the homogenization treatment of the core material ingot is not performed, it is possible to use it for the subsequent steps while maintaining a state in which the amount of dissolved Mn obtained at the time of casting is large. On the other hand, when homogenizing the core material ingot, the intermetallic compound in the core material ingot is re-dissolved by setting the ingot heating temperature to 550 ° C. or higher. It can use for a subsequent process as a state with much Mn amount. If the homogenization treatment temperature exceeds 620 ° C, the ingot may be melted. Therefore, the homogenization treatment temperature is preferably 620 ° C or less.

The obtained core material ingot is superposed in combination with the brazing material or sacrificial anode material as described above, heated in that state, and subjected to hot clad rolling. Here, this hot clad rolling is hereinafter simply referred to as “hot rolling”. The thickness of the laminated material before hot clad rolling is 250 to 800 mm ( desirably about 300 to 600 mm).

  About the heating before the hot rolling of the laminated material, it is set to 400 ° C. or more and 500 ° C. or less for 10 hours or less, and in the subsequent hot rolling, the thickness reduction amount reaches 50 mm after starting the hot rolling. The required time is 5 minutes or less, and further, the material temperature at the time when the plate thickness reduction amount reaches 50 mm is controlled to 400 ° C. or more and 450 ° C. or less, and after the plate thickness reduction amount reaches 50 mm, the plate thickness reaches 20 mm. 10 minutes or less, and the material temperature at the time when the plate thickness reaches 20 mm is controlled to 300 ° C. or more and 400 ° C. or less, and the time required from the start to the end of hot rolling is 40 minutes. The clad material is produced by controlling the following.

  The reason for determining the conditions of time and temperature at each stage during the heating before the hot rolling and the hot rolling is as follows.

  By setting the heating before hot rolling to 500 ° C. or less and 10 hours or less, excessive precipitation of intermetallic compounds during heating can be suppressed. If the heating before hot rolling is less than 400 ° C., the deformation resistance during hot rolling is large and rolling becomes difficult. On the other hand, if the heating before hot rolling exceeds 500 ° C. or exceeds 10 hours, an intermetallic compound is formed. Since it precipitates excessively, it becomes difficult to finally control the size and density of the intermetallic compound as described above. Therefore, heating of the overlapping material before hot rolling is performed at 400 to 500 ° C. for 10 hours. It was as follows. In addition, the more preferable conditions of the heating before hot rolling are 480 degrees C or less and 5 hours or less. In addition, in the heating before hot rolling, it is preferable that the heating time is short in order to obtain a preferable precipitate distribution, and if the temperature reaches within a range of 400 to 500 ° C., particularly the holding at that temperature is However, if the entire material does not reach a predetermined temperature uniformly, there is a possibility that problems such as poor clad crimping may occur.

  The laminated material heated as described above is immediately subjected to hot rolling. That is, hot rolling is started before the hot rolling start temperature is substantially lowered to a temperature lower than 400 ° C. During this hot rolling, precipitation of intermetallic compounds is promoted by the effect of applied strain, so it is extremely important to finish hot rolling in a short time.

From the start of hot rolling to a laminated plate having a thickness of 250 to 800 mm ( preferably about 300 to 600 mm) as described above, until the thickness reduction amount reaches 50 mm, core material and brazing material or sacrifice By controlling the time required for this step to 5 minutes or less and controlling the material temperature to be 450 ° C. or less when the plate thickness reduction amount reaches 50 mm, the step of pressure bonding the anode material, Excessive precipitation of intermetallic compounds can be suppressed. On the other hand, if the material temperature is less than 400 ° C. when the thickness reduction amount reaches 50 mm after the hot rolling is started, the core material and the brazing material or the sacrificial anode material cannot be sufficiently bonded. Therefore, the time from the start of hot rolling until the plate thickness reduction amount reaches 50 mm is 5 minutes or less, and the material temperature when the plate thickness reduction amount reaches 50 mm is regulated within the range of 400 to 450 ° C. It was decided.

  Furthermore, after starting the hot rolling, the material temperature is relatively high and the amount of strain applied is extremely large from the time when the thickness reduction amount reaches 50 mm until the thickness reaches 20 mm. By controlling the time required for this stage to 10 minutes or less and controlling the material temperature at the time when the plate thickness reaches 20 mm to 400 ° C. or less, excessive precipitation of intermetallic compounds can be suppressed. On the other hand, if the material temperature reaches 300 ° C. or less when the plate thickness reaches 20 mm, hot rolling becomes difficult and manufacturability is impaired. Therefore, it takes 10 minutes or less for the plate thickness to reach 20 mm after the plate thickness reduction amount reaches 50 mm in the middle of hot rolling, and the material temperature when the plate thickness reaches 20 mm is 300 ° C. or more and 400 ° C. or less. It was decided to control within the range.

  After the plate thickness reaches 20 mm, the material temperature has dropped, so no special control is required with respect to the time required for hot rolling in the subsequent stages. The total time until the end of rolling must be 40 minutes or less. If the total time from the start to the end of hot rolling exceeds 40 minutes, an intermetallic compound is excessively precipitated, and eventually an appropriate intermetallic compound distribution cannot be obtained.

  As described above, if the time required for each stage of hot rolling and the material temperature in each stage, and further the total time, deviate from the above definition, it is difficult to appropriately regulate the size and density of the intermetallic compound. . In addition, in order to suppress precipitation after winding on a coil after completion | finish of hot rolling, it is preferable that the completion | finish temperature of hot rolling shall be 250 degrees C or less.

  In addition, the specific means for controlling the time required for each stage of hot rolling as described above, the material temperature in each stage, and further the total time so that the above conditions are satisfied is not particularly limited. The temperature may be measured between each pass of the hot rolling, and means such as feedback control of the rolling speed, the amount of rolling reduction, the amount of rolling oil, etc. in the next pass may be applied so as to satisfy the above conditions.

  The aluminum alloy clad material obtained by hot rolling as described above is subjected to cold rolling and finished to a required product thickness (preferably about 0.15 to 0.6 mm). In the case of the method of the invention of claim 6, during the cold rolling, the intermediate annealing is performed at least once in the middle stage before reaching the final thickness. For this intermediate annealing, either a batch annealing furnace or a continuous annealing furnace (CAL) may be used. Such intermediate annealing is a process necessary for completely recrystallizing the material before the final cold rolling and improving the formability and brazing of the product plate after the final cold rolling.

  When batch annealing is applied to the intermediate annealing, the metal structure after the intermediate annealing can be completely recrystallized by setting the intermediate annealing temperature within the range of 250 ° C to 400 ° C, and the amount of dissolved Mn By increasing the number, the material in which the intermetallic compound is in a fine state can be obtained. If the intermediate annealing temperature by batch annealing is less than 250 ° C., a completely recrystallized metal structure cannot be obtained after intermediate annealing, while if it exceeds 400 ° C., an intermetallic compound having a size of 0.3 μm or more during intermediate annealing. Will precipitate excessively, making it difficult to properly regulate the intermetallic compound density. In addition, the more preferable temperature in the intermediate annealing by batch annealing is 300-370 degreeC.

  On the other hand, when intermediate annealing is performed using a continuous annealing furnace (CAL), by setting the intermediate annealing temperature within the range of 380 ° C. to 550 ° C., the metal structure after the intermediate annealing is completely recrystallized and simultaneously solidified. A state in which the amount of dissolved Mn is large and the intermetallic compound is fine and small can be obtained. When the intermediate annealing temperature in the continuous annealing furnace is less than 380 ° C., a completely recrystallized metal structure cannot be obtained after the intermediate annealing. Here, when a continuous annealing furnace is used for the intermediate annealing, the heating rate and the cooling rate are extremely fast, and precipitation during the intermediate annealing hardly occurs, so the upper limit of the intermediate annealing temperature is not particularly limited from the viewpoint of the metal structure. However, in order to prevent melting of the clad brazing material, the upper limit of the intermediate annealing is set to 550 ° C. or less. In the intermediate annealing using a continuous annealing furnace, the holding time at a temperature in the range of 380 to 550 ° C. is not particularly specified, but it is usually set to 5 minutes or less (including no holding).

  Here, in cold rolling with intermediate annealing in the middle, the rolling rate of cold rolling (primary cold rolling) before intermediate annealing is not particularly limited, and the hot ascent thickness and intermediate annealing are not limited. What is necessary is just to set suitably according to the last final cold rolling rate and product plate | board thickness later. On the other hand, the final cold rolling reduction after the intermediate annealing is desirably 5 to 50%. If the final cold rolling rate is large and a large strain is introduced by the final cold rolling, it becomes easy to cause brazing diffusion during brazing, and the strength of the material is increased, which hinders the subsequent forming process. There is a risk of causing. On the other hand, if the final cold rolling rate is small and the amount of strain is too small, the core material will not be sufficiently recrystallized before the brazing and melting at the time of brazing, and the subcrystalline grains will remain and braze through the subcrystalline grains Diffusion occurs. Although the optimum value of the final cold rolling rate varies depending on the intermediate annealing conditions, from the above viewpoint, it is usually desirable to be within the range of 5 to 50%, and more preferably 10 to 40%.

  The clad material that has been made into a product plate thickness by final cold rolling as described above may be molded as a brazing sheet as it is into a high-temperature compressed air or refrigerant passage component (tube) in a heat exchanger, If the forming shape is complicated and it is difficult to form as it is, softening annealing may be performed after the final cold rolling to improve the formability, and this is defined in the invention of claim 7.

  The heating temperature in this softening annealing shall be 200 to 400 degreeC. If the heating temperature is less than 200 ° C., the moldability is not sufficiently improved. On the other hand, if the heating temperature exceeds 400 ° C., the intermetallic compound is excessively precipitated, so that an appropriate distribution of the intermetallic compound cannot finally be obtained. . The heating temperature for softening annealing is more preferably in the range of 250 ° C to 350 ° C. In addition, the heating time in the soft annealing is not particularly limited, but it is usually desirable that the heating time be about 1 hour to 10 hours. If the heating time is less than 1 hour, the strength of the brazing sheet may not be uniform over the entire coil, while if it exceeds 10 hours, the effect of soft annealing is saturated and the economic efficiency is only impaired.

  Here, in the above description, the intermediate annealing is performed in the middle of the cold rolling after the hot rolling, but the intermediate annealing is omitted and the intermediate sheet is not subjected to the intermediate annealing and is cold-rolled to the final thickness. It may be rolled. However, in that case, soft annealing is performed after a required plate thickness is obtained by cold rolling. This is defined by the invention of claim 8.

  Even when the intermediate annealing is omitted in this way, the conditions before heating and during hot rolling may be the same as those already described. Moreover, the rolling rate of cold rolling (without intermediate annealing) after hot rolling is not particularly limited, but it is usually 5 to 95%. If the cold rolling rate is less than 5%, the core material is not sufficiently recrystallized before the brazing and melting at the time of brazing, and there is a possibility that subcrystalline grains remain and wax diffusion occurs through the subcrystalline grains. On the other hand, if it exceeds 95%, the strength of the material becomes too high, and it may be difficult to roll to the target plate thickness. Moreover, the conditions of the soft annealing after cold rolling should just be the same as the above-mentioned case, What is necessary is just to set it as the conditions heated for 1 to 10 hours at the temperature within the range of 200-400 degreeC. As described above, in the process in which the intermediate annealing is omitted, excessive precipitation of the intermetallic compound can be suppressed, so that it is easy to appropriately regulate the size and density of the intermetallic compound.

  In the above, the thickness of the aluminum alloy brazing sheet of the present invention is not particularly limited, but in the case of the brazing sheet of the present invention, since it is thin, it has high high-temperature strength and good brazeability, so It is a great merit that it can withstand high temperature and high pressure as an intercooler tube material that circulates compressed air and can exhibit excellent durability. Therefore, for these applications, in order to take advantage of the advantage that the weight can be reduced while maintaining sufficient durability, it can be used as a thin material of about 0.6 mm or less (usually 0.15 mm or more). Is appropriate. However, it is not limited to the plate thickness within this range, and it is of course possible to use it as a relatively thick material of about 0.6 mm or more and about 5 mm or less. Incidentally, in the case of the above-described intercooler tube material that circulates compressed air by a turbocharger in an automobile, it can be used as a thin material of about 0.6 mm or less.

  Further, the clad rate of the brazing material in the aluminum alloy brazing sheet of the present invention is not particularly limited, but it is usually preferably about 3 to 20% per side. In addition, when the sacrificial anode material is clad on one side of the core material, the clad rate of the sacrificial anode material layer is not particularly limited, but usually it may be about 3 to 20%.

  Hereinafter, the present invention will be described in more detail based on examples. It should be noted that this example is for explaining the effects of the present invention until it is tired, and the technical scope of the present invention is not limited by the example.

  A core material and a skin material alloy (alloy for sacrificial anode material) having the alloy components and compositions shown in Tables 1 and 2 were cast by the DC casting method, respectively, and both sides were chamfered to a thickness of 500 mm. As the brazing material, a JIS 4045 alloy was used, and the brazing material and the sacrificial anode material were each rolled to a thickness of 50 mm by hot rolling according to a conventional method. Using these alloys, the brazing material was combined as the skin material 1 on one side of the core material, and the brazing material or the sacrificial anode material shown in Table 2 was combined and laminated on the other surface. The total thickness in that state was 600 mm. Specific combinations are shown in Table 5. In this state, the clad rate was 10% per side, and the total thickness was 600 mm. For such a laminated material, heating and hot rolling are performed under the conditions shown in Table 3 to obtain a 3.5 mm three-layer clad material, and further to this clad material, primary cold rolling is performed under the conditions shown in Table 4. Intermediate annealing and final cold rolling were performed to obtain a H1n tempered sheet material having a thickness of 0.4 mm, and further subjected to soft annealing. In some cases, intermediate annealing and / or softening annealing was omitted.

  About the obtained brazing sheet, since intermetallic compound distribution density was investigated by the method shown below, the result is shown in Table 5. Further, each brazing sheet was evaluated for the high-temperature strength after brazing, the fin joint ratio, the cyclic pressure resistance, the erosion resistance, the giant intermetallic compound, and the corrosion resistance by the methods shown below. The results are shown in Table 6. In addition, regarding corrosion resistance, only those using a sacrificial anode material as a skin material were evaluated, and those not clad with a brazing material without using a sacrificial anode material were excluded from evaluation.

(1) Density of intermetallic compound:
The core material portion of each brazing sheet was examined by polishing the L-LT surface and performing observation with a transmission electron microscope (TEM). At this time, the film thickness of the observation part was measured from the equal-thickness interference fringes, TEM observation was performed only at a location where the film thickness was about 0.1 to 0.2 μm, and 10 fields were observed at a magnification of 1000 times for each sample. The density of the intermetallic compound of each size after brazing was determined by image analysis of TEM photographs of each field of view. In addition, the distribution density of the intermetallic compound after brazing shown in Table 5 was represented by an average value obtained from 10 fields of view.

(2) High temperature strength after brazing:
After the brazing heat of 600 ° C. × 3 minutes, it was cooled at a cooling rate of 200 ° C./min, and then left in a furnace at 200 ° C. for 1 week. This sample was heated to 200 ° C. at 30 ° C./min, held for 10 minutes, and subjected to a tensile test according to JIS Z2241 under the conditions of a tensile speed of 10 mm / min and a gauge length of 50 mm. The tensile strength was read from the obtained stress-strain curve, and “◯” was entered in Table 6 as a pass when it was 100 MPa or more, and “X” was entered as a failure when it was less than 100 MPa.

(3) Fin joint rate:
After corrugating 3003 alloy fin material and combining it with the brazing filler metal surface of the test material, it is immersed in 5% fluoride flux aqueous solution, dried at 200 ° C, and 600 ° C x 3 minutes of Nocolok brazing Heating was performed. If the test core has a fin joint rate of 100%, it will be marked as “O”, if it is less than 100% and over 95%, it will be marked “△”, and if it is less than 95%, it will be marked “X”. Filled in Table 6.

(4) Repetitive pressure resistance:
Each brazing sheet obtained as described above is formed into a flat tube shape by electro-sewing process, while a fin material of 3003 alloy is corrugated and, as shown in FIG. Corrugated fins 2 and two brazing sheets 3 having a thickness of 1 mm and two 3003 alloy plates 4 having a thickness of 10 mm are combined and immersed in a 5% fluoride flux aqueous solution and dried at 200 ° C. A test core 5 was prepared by applying Noclock brazing heat at 600 ° C. for 3 minutes. The brazing sheet 3 is obtained by clad 4045 alloy brazing material on both sides of a 3003 alloy core material. The test core 5 is sandwiched and fixed between a pair of jigs 8 of a repeated pressure resistance test apparatus as shown in FIG. 2 via a packing 9, and a hydraulic apparatus (not shown) is installed in the flat tube 1 of the test core 5. The oil pressure was repeatedly applied through the pipe 6 under conditions of a temperature of 150 ° C., a pressure of 170 kPa, and a frequency of 1 Hz. As a result, when there was no abnormality at the number of repetitions of 1 million times or more, “○” is indicated as a pass, and when a tube defect occurs at the number of repetitions less than 1 million times, “X” is indicated as a rejection. Filled out in 6.

(5) Erosion resistance:
After producing a test core similar to the repeated pressure resistance test under the same conditions as described above, cross-sectional micro observation was performed to confirm the occurrence of erosion. In Table 6, “O” marks are marked as acceptable when there is no erosion, and “X” marks are marked as unacceptable when there is erosion.

(6) Giant intermetallic compound:
The L-ST surface of the core part of each brazing sheet was surfaced by polishing, etched with Keller's solution, and then observed with an optical microscope. Each test material was sampled and observed at random of 10 samples, and if a huge intermetallic compound with an equivalent circle diameter of 100 μm or more was not observed, the test was passed, and “O” was not observed. Each pass was marked with a “x” mark in Table 6.

(7) Corrosion resistance evaluation:
Similar to the tensile test specimen, after brazing heating of 600 ° C. × 3 minutes, to seal the brazing material _{^{side, Cl - 500ppm, SO 4 2-}} 100ppm, high temperature water of 88 ° C. containing Cu 2+ 10 ppm 8 A cycle immersion test with a cycle of 16 hours at room temperature and 16 hours was conducted for 3 months. Those that did not cause corrosion penetration were indicated as “O” as acceptable, and those that occurred as “X” as unacceptable. Filled out in 6.

As can be seen from these tables, No. 1-No. 8, no. 13-No. 20, no. 29-No. In the case of 31, the alloy composition of the core material and the hot rolling conditions satisfy the conditions specified in the present invention, and the intermetallic compound of 0.1 μm or more and less than 0.3 μm as the metal structure of the core material after the final cold rolling The density of the intermetallic compound having a density of 10 pieces / μm ² or less and a density of 0.3 μm or more was 0.5 pieces / μm ² or less, satisfying the conditions of the metal structure defined in the present invention.

  In contrast, no. 9-No. No. 12 is an example in which the alloy component of the core material does not satisfy the conditions defined in the present invention. No. 21-No. No. 28, the alloy component of the core material satisfies the conditions specified in the present invention, but the manufacturing process is out of the conditions of the present invention. As a result, in these examples, the conditions of the metal structure are all specified in the present invention. Was out of range. And no. 32, no. Example 33 is an example in which an alloy deviating from the alloy component composition of the sacrificial anode material defined in the present invention is used as the single-sided skin material 2.

  Furthermore, based on these tables, the present invention examples and comparative examples will be examined in detail.

  As is apparent from Table 6, this is an example of the present invention, the density condition of the intermetallic compound, No. 1 satisfying the provisions of this invention. 1-No. 5, no. 13-No. In the example of 16, the tensile strength at a high temperature (200 ° C.) after brazing is as high as 80 MPa or more, the fin joint rate is 100%, and the test core using these materials is subjected to a repeated pressure test at a high temperature. It was confirmed that the tube had no defects and had excellent heat resistance for 1 million times or more. Of these invention examples, No. 1 containing Mg in the core material. 6-No. 8, no. 17-No. In the case of No. 20, when the tensile strength at high temperature (200 ° C.) after brazing is 100 MPa or higher, a higher high-temperature strength is obtained, and the fin joint ratio is 95% or more and less than 100% and no Mg is added. Although it is inferior to this, it can be said that there is no problem if the high temperature strength of the material is high. Furthermore, these invention examples No. 1-No. 8, no. 13-No. All of the 20 materials were excellent in erosion resistance, and there was no giant intermetallic compound of 100 μm or more, and it was confirmed that they were suitable for use as a heat exchanger material.

  On the other hand, no. 10-No. In 12 comparative examples, the tensile strength at high temperature (200 ° C.) after brazing was less than 80 MPa, and the test cores using these materials were defective in the tube in less than 1 million times in the repeated pressure test at high temperature. Has occurred.

  Further, No. of the comparative example in which the core material does not contain Mg and the manufacturing process is out of the conditions defined in the present invention. 21-No. 24, the tensile strength at a high temperature (200 ° C.) after brazing was less than 80 MPa, and the test cores using these materials had defects in the tube in less than 1 million cycles in the repeated pressure test at high temperatures. Oops.

  Furthermore, the core material contains Mg, and the manufacturing process is outside the conditions specified in this invention. 25-No. In the comparative example of 28, the tensile strength at a high temperature (200 ° C.) after brazing is less than 80 MPa, and the fin joint ratio is 95% or more and less than 100%. Is an inadequate level. And these No. 25-No. In the test core using the material of 28 examples, the tube was defective in less than 1 million times in the repeated pressure resistance test at high temperature.

  On the other hand, no. In the case of Example 9, there was a giant intermetallic compound of 100 μm or more, and poor bonding and erosion of fins occurred during brazing.

  Further, No. 1 in which a sacrificial anode material is clad on one side of the core material. 29-No. For the 33 examples, corrosion resistance was also evaluated. Among these, No. which is an example of the present invention. 29-No. In the example 31, corrosion penetration was not seen and the corrosion resistance was good. On the other hand, No. which is a comparative example. 32, no. In the case of 33, corrosion penetration occurred and the corrosion resistance was insufficient. No. 29-No. In the case of 33, the tensile strength at a high temperature (200 ° C.) after brazing is as high as 80 MPa or more. Therefore, from this result, the fact that one of the skin materials is a sacrificial anode material has an influence on the high temperature strength. Not confirmed.

  From the above examples, the brazing sheet of the present invention is excellent in high-temperature strength, has good brazing properties, does not contain a giant intermetallic compound, has excellent productivity, and is a heat exchanger tube material, It is clear that it is particularly suitable for a tube material used under high temperature and high pressure such as an intercooler.

1 flat tube 2 corrugated fin 3 brazing sheet 5 test core

Claims (9)

In a method for producing an aluminum alloy brazing sheet comprising an Al—Si brazing material clad on one or both sides of a core material made of an aluminum alloy;
The aluminum alloy of the core material is Si 0.05% (mass%, hereinafter the same) or more and less than 0.3%, Fe0.05-0.4%, Cu0.3-1.2%, Mn0.8-1.8 1% or more selected from Ti0.05-0.3%, Zr0.05-0.3%, Cr0.05-0.3%, V0.05-0.3% The balance is made of Al and inevitable impurities, and the distribution density of the intermetallic compound of 0.1 μm or more and less than 0.3 μm in the plate cross section in the thickness direction is 10 / μm ² as the metal structure of the core part. In producing a high heat-resistant aluminum alloy brazing sheet having a distribution density of intermetallic compounds of 0.3 μm or more and 0.5 pieces / μm ² or less ,
An Al-Si alloy brazing material is superposed on one side or both sides of the core material, and these are heated and hot-rolled to form a clad material, and the resulting clad material is cooled. A cold rolling process for cold rolling, and an intermediate annealing process for performing intermediate annealing at least once in the middle of cold rolling;
In the hot clad rolling step, the thickness of the overlapped material before hot clad rolling is 250 mm or more and 800 mm or less, and heating before hot clad rolling is performed at a temperature in the range of 400 ° C. or more and 500 ° C. or less for 10 hours or less. In addition, the time required for the plate thickness reduction amount to reach 50 mm after starting hot clad rolling is controlled to 5 minutes or less, and the material temperature when the plate thickness reduction amount reaches 50 mm is set to 400 ° C. The temperature is controlled to 450 ° C. or less, and the time required for the plate thickness to reach 20 mm after the plate thickness reduction amount reaches 50 mm is controlled to 10 minutes or less, and the material temperature when the plate thickness reaches 20 mm. Is controlled between 300 ° C. and 400 ° C., and the time required from the start of hot clad rolling to the end of hot clad rolling is controlled to 40 minutes or less. Also the in the intermediate annealing step performs intermediate annealing at a temperature within the range of 250 ° C. to 400 ° C. using a furnace of a batch type, wherein the high heat resistant aluminum alloy brazing sheet manufacturing method of. In the manufacturing method of the high heat resistant aluminum alloy brazing sheet according to claim 1,
A method for producing a high heat-resistant aluminum alloy brazing sheet, wherein an alloy containing 0.05 to 0.5% of Mg is used in addition to each of the component elements as the aluminum alloy of the core material. In a method for producing an aluminum alloy brazing sheet comprising an Al—Si brazing material clad on one or both sides of a core material made of an aluminum alloy;
The aluminum alloy of the core material is Si 0.05% (mass%, hereinafter the same) or more and less than 0.3%, Fe0.05-0.4%, Cu0.3-1.2%, Mn0.8-1.8 1% or more selected from Ti0.05-0.3%, Zr0.05-0.3%, Cr0.05-0.3%, V0.05-0.3% The balance is made of Al and inevitable impurities, and the distribution density of the intermetallic compound of 0.1 μm or more and less than 0.3 μm in the plate cross section in the thickness direction is 10 / μm ² as the metal structure of the core part. In producing a high heat-resistant aluminum alloy brazing sheet having a distribution density of intermetallic compounds of 0.3 μm or more and 0.5 pieces / μm ² or less,
An Al-Si alloy brazing material is superposed on one side or both sides of the core material, and these are heated and hot-rolled to form a clad material, and the resulting clad material is cooled. A cold rolling process for cold rolling, and an intermediate annealing process for performing intermediate annealing at least once in the middle of cold rolling;
In the hot clad rolling step, the thickness of the overlapped material before hot clad rolling is 250 mm or more and 800 mm or less, and heating before hot clad rolling is performed at a temperature in the range of 400 ° C. or more and 500 ° C. or less for 10 hours or less. The time required for the plate thickness reduction amount to reach 50 mm after the start of hot clad rolling is controlled to 5 minutes or less, and the material temperature when the plate thickness reduction amount reaches 50 mm is 400 ° C. or more. The time required until the plate thickness reaches 20 mm after the plate thickness reduction amount reaches 50 mm is controlled to 450 ° C. or less, and the material temperature at the time when the plate thickness reaches 20 mm is controlled. The temperature is controlled between 300 ° C. and 400 ° C., and the time required from the start of hot clad rolling to the end of hot clad rolling is controlled to 40 minutes or less. Serial in the intermediate annealing step, and performing intermediate annealing at a temperature within the range of from 380 to 550 ° C. using a furnace of a continuous, high heat resistance aluminum alloy brazing sheet manufacturing method of. In the manufacturing method of the highly heat-resistant aluminum alloy brazing sheet according to claim 3,
A method for producing a high heat-resistant aluminum alloy brazing sheet , wherein an alloy containing 0.05 to 0.5% of Mg is used in addition to each of the component elements as the aluminum alloy of the core material . In the method for producing a high heat-resistant aluminum alloy brazing sheet according to any one of claims 1 to 4 ,
A method for producing a highly heat-resistant aluminum alloy brazing sheet, comprising performing a soft annealing step of heating to a temperature within a range of 200 to 400 ° C after the cold rolling step . In a method for producing an aluminum alloy brazing sheet comprising an Al—Si brazing material clad on one or both sides of a core material made of an aluminum alloy;
The aluminum alloy of the core material is Si 0.05% (mass%, hereinafter the same) or more and less than 0.3%, Fe0.05-0.4%, Cu0.3-1.2%, Mn0.8-1.8 1% or more selected from Ti0.05-0.3%, Zr0.05-0.3%, Cr0.05-0.3%, V0.05-0.3% The balance is made of Al and inevitable impurities, and the distribution density of the intermetallic compound of 0.1 μm or more and less than 0.3 μm in the plate cross section in the thickness direction is 10 / μm ² as the metal structure of the core part. In producing a high heat-resistant aluminum alloy brazing sheet having a distribution density of intermetallic compounds of 0.3 μm or more and 0.5 pieces / μm ² or less,
A hot clad rolling process in which an Al-Si alloy brazing material is superposed on one side or both sides of the core material and heated and hot rolled to form a clad material, and the resulting clad material is cold rolled. A cold rolling step, and a softening annealing step performed after the cold rolling step,
In the hot clad rolling step, the thickness of the overlapped material before hot clad rolling is 250 mm or more and 800 mm or less, and heating before hot clad rolling is performed at a temperature in the range of 400 ° C. or more and 500 ° C. or less for 10 hours or less. The time required for the plate thickness reduction amount to reach 50 mm after the start of hot clad rolling is controlled to 5 minutes or less, and the material temperature when the plate thickness reduction amount reaches 50 mm is 400 ° C. or more. The time required for the plate thickness to reach 20 mm after the plate thickness reduction amount reaches 50 mm is controlled to 450 ° C. or less, and the material temperature when the plate thickness reaches 20 mm is controlled. The temperature is controlled between 300 ° C. and 400 ° C., and the time required from the start of hot clad rolling to the end of hot clad rolling is controlled to 40 minutes or less. In the softening annealing step, characterized in that the heating temperature in the range of 200 to 400 ° C., high heat resistance aluminum alloy brazing sheet manufacturing method of. In the manufacturing method of the high heat-resistant aluminum alloy brazing sheet of Claim 6 ,
A method for producing a high heat-resistant aluminum alloy brazing sheet , wherein an alloy containing 0.05 to 0.5% of Mg is used in addition to each of the component elements as the aluminum alloy of the core material . In the manufacturing method of the high heat resistant aluminum alloy brazing sheet of any one of Claims 1-7;
An Al—Si alloy brazing material is superposed on one surface of the core material, and the other surface of the core material contains Zn 1.0 to 6.0%, Fe 0.05 to 0.4%, and the balance is A method for producing a high heat-resistant aluminum alloy brazing sheet, characterized in that an Al—Zn-based aluminum alloy sacrificial anode material made of Al and inevitable impurities is superposed and heated in this state for hot clad rolling . In the manufacturing method of the high heat resistant aluminum alloy brazing sheet of Claim 8 ;
As the Al—Zn-based aluminum alloy sacrificial anode material, in addition to the above component elements, Si 1.0% or less, Mn 1.8% or less, Ti 0.02 to 0.3%, V 0.02 to 0.3% A method for producing a highly heat-resistant aluminum alloy brazing sheet, comprising using an alloy containing one or more selected from among them .

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