JP5435988B2 - High heat resistant aluminum alloy brazing sheet and method for producing the same - 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. The present invention relates to a brazing sheet and a manufacturing method thereof.

  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. Especially in automobile intercoolers, high-temperature and high-pressure loads continue to be applied for a long time during driving, so even if temporary load does not cause deformation or destruction, creep deformation will occur over a long period of time, causing damage. There is a risk. Furthermore, if the intercooler is used at a high temperature when the automobile is running, the tube will thermally expand, but if it returns to room temperature when it stops, it will shrink again. If the strength of the material at room temperature is insufficient, plastic deformation will occur. It may occur and lead to destruction. For these reasons, the intercooler tube material is required to have a high level of room temperature strength and creep resistance.

  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 room temperature strength after brazing of the clad material using JIS3003 alloy core material is only about 120 MPa tensile strength, and the creep resistance is less than a few hours when a load of 60 MPa is applied at 200 ° C. As a result, the tube material of the intercooler used at a recent high temperature and high pressure was insufficient in both room temperature strength and creep resistance.

  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, with these proposed techniques, it has been difficult to reliably and stably obtain heat resistance, particularly strength and creep resistance 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

  The present invention has been made against the background of the above circumstances, in order to satisfy the requirements for high heat resistance and thinning of aluminum alloy brazing sheets used as automotive intercooler tube materials, As a basic problem, to provide a brazing sheet having improved strength such as creep resistance and having high strength and creep resistance that can withstand use at a high temperature of about 200 ° C., which has been difficult to achieve with conventional technology. Yes. In the present invention, as described above, not only has excellent strength and creep resistance after brazing, but also as a brazing material, there is little brazing diffusion during brazing, and brazing is also good. It is an object of the present invention to provide an aluminum alloy brazing sheet, particularly an aluminum alloy brazing sheet that can be suitably used as a fluid passage constituting material (tube material) of a heat exchanger for automobiles, and a method for producing the same.

  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 an aluminum alloy brazing sheet in which an aluminum alloy brazing sheet is clad on one or both sides of a core material made of an aluminum alloy. 1.2%, Fe 0.05-0.4%, Cu 0.3-1.2%, Mn 0.8-1.8%, Ti 0.05-0.3%, Zr 0.05-0 .3%, Cr 0.05 to 0.3%, V 0.05 to 0.3%, one or more selected from the group consisting of Al and inevitable impurities, and the metal structure of the core part The distribution density of intermetallic compounds of 0.1 μm or more and less than 0.3 μm in the plate cross section in the thickness direction is 20 / μm ² or more and 100 / μm ² or less, and the distribution of intermetallic compounds of 0.3 μm or more density is one / μm ² or more It is characterized in that it.

  The invention according to claim 2 is the high heat-resistant aluminum alloy brazing sheet according to claim 1, wherein the aluminum alloy of the core material further contains 0.05 to 0.5% of Mg in addition to the respective component elements. It is characterized by.

  Further, the invention according to claim 3 is the high heat-resistant aluminum alloy brazing sheet according to any one of claims 1 and 2, wherein an Al-Si brazing material is formed on one surface of the core material. The other surface is clad with a sacrificial anode material made of an Al—Zn-based aluminum alloy, and the Al—Zn-based aluminum alloy sacrificial anode material has Zn of 1.0 to 6.0% and Fe of 0.05 to 0.4%. And the balance is made of Al and inevitable impurities.

  And the invention of claim 4 is the high heat resistant aluminum alloy brazing sheet according to claim 3, wherein the Al—Mn based aluminum alloy sacrificial anode material is Si 1.0% or less, Mn1 .8% or less, Ti 0.02 to 0.3%, or V 0.02 to 0.3%.

On the other hand, the invention of claim 5 is a method for producing an aluminum alloy brazing sheet described in claim 1 or claim 2, and is described in claim 1 or claim 2. A hot clad rolling process in which an Al-Si alloy brazing material is superposed on one side or both sides of a material for an aluminum alloy core material having the above-described composition and heated to form a clad material by hot rolling. a cold rolling step of cold rolling the clad material that has been made and an intermediate annealing step of performing at least one intermediate annealing at midway of the cold rolling, in the hot clad rolling process, hot clad rolling the thickness before superposition material and 250mm above 800mm or less, the heating before hot clad rolling at a temperature in the range of 400 ° C. or higher 500 ° C. or less subjected to 10 hours, In addition, 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 set to 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 minutes or less, and the material temperature when the plate thickness reaches 20 mm is controlled. It is controlled to 300 ° C. or more and 400 ° C. or less, and further, the time required from the start of hot clad rolling to the end of hot clad rolling is controlled to 40 minutes or less. Further, in the intermediate annealing step, batch type The intermediate annealing is performed at a temperature within a range of 250 ° C. to 400 ° C. using a furnace.

The invention of claim 6 is a method for producing the aluminum alloy brazing sheet described in claim 1 or claim 2, and is described in claim 1 or claim 2. A hot clad rolling process in which an Al-Si alloy brazing material is superposed on one side or both sides of a material for an aluminum alloy core material having the above-described composition and heated to form a clad material by hot rolling. a cold rolling step of cold rolling the clad material that has been made and an intermediate annealing step of performing at least one intermediate annealing at midway of the cold rolling, in the hot clad rolling process, hot clad rolling the thickness before superposition material and 250mm above 800mm or less, the heating before hot clad rolling at a temperature in the range of 400 ° C. or higher 500 ° C. or less subjected to 10 hours, The time required for the plate thickness reduction amount to reach 50 mm after the start of inter-clad rolling is controlled to 5 minutes or less, and the material temperature at the time when the plate thickness reduction amount reaches 50 mm is 400 ° C. or more and 450 ° C. or less. In addition, 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 300 ° C. or more. It is controlled to 400 ° C. or less, 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. Further, in the intermediate annealing step, a continuous furnace is used. Intermediate annealing at a temperature within a range of 380 to 550 ° C.

  Furthermore, the invention according to claim 7 is the method for producing a high heat-resistant aluminum alloy brazing sheet according to any one of claims 5 and 6, and is heated to 200 to 400 ° C. after the cold rolling step. The softening annealing process is performed.

The invention of claim 8 is a method for producing an aluminum alloy brazing sheet according to any one of claims 1 or 2, wherein A hot clad rolling process in which an Al-Si alloy brazing material is superposed on one side or both sides of a raw material for an aluminum alloy core material having the described composition and heated to form a clad material by hot rolling; A cold rolling process for cold rolling the clad material, and a softening annealing process performed after the cold rolling process, and in the hot clad rolling process, the thickness of the overlapped material before hot clad rolling 250 mm or more and 800 mm or less, and heating before hot clad rolling is performed for 10 hours or less at a temperature within a range of 400 ° C. or more and 500 ° C. or less, and after hot clad rolling is started, the plate The time required for the thickness reduction amount to reach 50 mm is controlled to 5 minutes or less, and the material temperature when the thickness reduction amount reaches 50 mm is controlled to 400 ° C. or more and 450 ° C. or less. The time required for the plate thickness to reach 20 mm after reaching 50 mm is controlled to 10 minutes or less, and the material temperature when the plate thickness reaches 20 mm is controlled to 300 ° C. to 400 ° C. The time required from the start of hot clad rolling to the end of hot rolling is controlled to 40 minutes or less, and the heating temperature in the softening annealing step is within a range of 200 to 400 ° C. It is.

  The invention of claim 9 is the method for producing a high heat-resistant aluminum alloy brazing sheet according to any one of claims 5 to 8, wherein an Al-Si alloy brazing material is provided on one surface of the core material. And the sacrificial anode material having the component composition according to any one of claims 3 and 4 is superimposed on the other surface of the core material, and heated in that state for hot clad rolling. It is characterized by providing.

  The aluminum alloy brazing sheet of the present invention is not only excellent in brazing properties such as fin joint ratio and erosion resistance, but also strength and creep resistance after brazing even if the thickness is reduced to about 0.6 mm or less. It has excellent durability and is highly durable for use at high temperatures of about 200 ° C. Therefore, it is extremely excellent as a thin-walled brazing sheet used at high temperatures and high pressures, such as automotive heat exchangers, especially intercooler tubes. It is possible to reduce the weight of the heat exchanger and extend its life at the same time.

  Moreover, according to the manufacturing method of this invention, the aluminum alloy brazing sheet which has the outstanding characteristic as mentioned above can actually be manufactured reliably and stably.

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

  A preferred embodiment of the aluminum alloy brazing sheet and the manufacturing method thereof of the present invention will be described in detail below.

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

[Heart]
The core aluminum alloy contains Si 0.3-1.2%, Fe 0.05-0.4%, Cu 0.3-1.2%, Mn 0.8-1.8%, and Ti0.05 ~ 0.3%, Zr0.05 ~ 0.3%, Cr0.05 ~ 0.3%, V0.05 ~ 0.3% contains one or more, the balance is Al and inevitable A material made of a general impurity is used. The reasons for limiting the components of such a core material alloy are as follows.

Si:
Si forms an Al-Mn-Si intermetallic compound together with Mn and contributes to improving the strength of the core material by dispersion strengthening, and Si dissolved in the aluminum matrix phase increases strength and creep resistance by solid solution strengthening. Contributes to the improvement of sex. Si also contributes to strength improvement by reacting with Mg to form a Mg ₂ Si compound. Here, if the Si content is less than 0.6%, the effect of Si addition is small. On the other hand, if it exceeds 1.2%, the melting point of the core material is lowered, and the core material may be melted during brazing. Therefore, the Si content of the core material is set in the range of 0.3 to 1.2%.

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, which increases the cost. 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%.

Cu:
Cu contributes to improvement in strength and creep resistance by solid solution strengthening. If the Cu content is less than 0.3%, these effects due to the addition of Cu are small. On the other hand, if the Cu content exceeds 1.2%, the possibility of cracking during casting increases. The amount of Cu was in the range of 0.3 to 1.2%. Preferably, the Cu amount is in the range of 0.5 to 1.0%.

Mn:
Mn forms an Al-Mn-Si intermetallic compound together with Si and contributes to improving the strength by dispersion strengthening. On the other hand, Mn dissolved in the aluminum matrix is strengthened and creep-resistant by solid solution strengthening. Contributes to the improvement of sex. If the Mn content is less than 0.5%, these effects due to the addition of Mn are 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 reduced. Let 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. All of these elements contribute to the improvement of strength and creep resistance, and these will be described next.

Ti:
Ti is an element that improves strength and creep resistance 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 small amount (usually 0.005 to 0.05%) of Ti may be added to refine the structure of the ingot. 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 also an element that improves strength and creep resistance by solid solution strengthening, and addition of Zr precipitates an Al-Zr-based intermetallic compound, which improves strength and creep resistance by dispersion strengthening. It can be added within a range of 0.05 to 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 strength and creep resistance by solid solution strengthening, and Al—Cr-based intermetallic compounds are precipitated by addition of Cr, thereby improving strength and creep resistance by dispersion strengthening. It can be added within a range of ˜0.3%. 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 strength and creep resistance 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 giant intermetallic compound is easily generated, 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. 0.05% to 0.5% may be added.

That is, Mg is an element that improves strength and creep resistance by precipitation of Mg ₂ Si, and may be added as necessary to further improve strength and creep resistance. 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 such a sacrificial anode material alloy 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 of the Al—Zn-based alloy used as the sacrificial anode material may be basically Al and inevitable impurities, but as defined mainly in claim 4 for strength improvement. In addition, 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 the strength by dispersion strengthening, and Si dissolved in the matrix improves the strength by solid solution strengthening. 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 strength improvement. Here, if the amount of Si in the sacrificial anode material exceeds 1.0%, the melting point of the sacrificial anode material decreases, and the possibility of melting during brazing heat increases, and Si increases the potential of the sacrificial anode material. If it is a noble element and the Si content exceeds 1.0%, the sacrificial anode effect is hindered and the corrosion resistance is lowered. 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 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 strength and improves corrosion resistance by solid solution strengthening, 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%. In addition, 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 in order to refine the structure during casting. Therefore, an extremely small 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 also has such a purpose. It is permissible to add Ti and B.

V:
V improves strength by solid solution strengthening and is effective in improving 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 state of dispersion of intermetallic compounds in the product sheet after rolling 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 the intermetallic compound having a size of 0.1 μm or more and less than 0.3 μm in the cross section in the thickness direction is 20 / μm ² or more and 100 Pieces / μm ² or less, preferably 30 pieces / μm ² or more and 50 pieces / μm ² or less, and the distribution density of intermetallic compounds having a size of 0.3 μm or more must be 1 piece / μm ² or less. It is. In addition, all the sizes of the intermetallic compound prescribed | regulated here shall mean a circle equivalent diameter.

  The reason for determining the distribution density of the intermetallic compound in the core part as described above is as follows.

In the core material of the aluminum alloy brazing sheet of the present invention, basically, solid solution strengthening by a solid solution element mainly composed of Mn and dispersion strengthening by an intermetallic compound (mainly Al-Mn-Si intermetallic compound) are mainly performed. In the core material of the aluminum alloy brazing sheet according to claim 2, the strength and creep resistance of the aluminum alloy brazing sheet according to claim 2 are further improved by age hardening due to precipitation of Mg ₂ Si. We are trying to improve. Here, when Mg is added to the core material, the brazing property is lowered, but when the creep resistance is sufficiently high, sufficient durability is obtained with Mg ₂ Si against a long-term pressure load at a high temperature. Is possible.

  Since intermetallic compounds contain a considerable amount of Mn and Si, if the amount of intermetallic compounds increases, the solid solution elements mainly composed of Mn tend to decrease. Therefore, due to the solid solution elements mainly composed of Mn. It can be said that solid solution strengthening and dispersion strengthening by an intermetallic compound are in a contradictory relationship. Therefore, in order to ensure sufficient strength and creep resistance after brazing heat, it is necessary to properly balance solid solution strengthening, dispersion strengthening, and age hardening after brazing heat. As described above, intermetallic compounds of a specific size are distributed at a density within a specific range as the metal structure of the core material portion of the product plate after the final cold rolling (the brazing sheet before brazing heat addition). It is necessary to obtain an adequate balance between solid solution strengthening, age hardening, and dispersion strengthening after the heat of brazing for the first time, and sufficient strength and creep resistance can be obtained. The brazing conditions are not particularly limited, and are usually performed by heating to about 600 ° C. and then air cooling. Here, the strength and creep resistance after brazing addition heat are also normal. It shall mean the performance after brazing under conditions.

  Further, the reason for limiting the distribution density condition of the metal compound as described above will be described in detail.

First, in terms of solid solution strengthening and age hardening, in order to ensure solid solution strengthening by securing the amount of solid solution elements mainly composed of Mn after brazing addition heat, and to further enhance age hardening by Mg ₂ Si. In the aluminum alloy brazing sheet after final cold rolling (that is, the brazing sheet before brazing addition heat), the density of intermetallic compounds of 0.1 μm or more and less than 0.3 μm is 100 / μm ² or less, more preferably It is necessary that the distribution density of the intermetallic compound of 50 μm / μm ² or less and 0.3 μm or more is 1 / 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, sufficient solid solution strengthening and age hardening 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 strength and creep resistance, and one or more of these elements are added. If the element is dissolved in the aluminum alloy matrix of the core material at the stage after brazing, a further sufficient solid solution strengthening can be exhibited. On the other hand, in the core part of the aluminum alloy brazing sheet after the final rolling, when more than 100 μm ² of intermetallic compounds of 0.1 μm or more and less than 0.3 μm are included, and one intermetallic compound of 0.3 μm or more When more than / μm ² is contained, a sufficient amount of solid solution such as Mn cannot be secured after the heat of brazing addition, and the effect of solid solution strengthening cannot be expected.

Next, from the viewpoint of dispersion strengthening, in order to enhance the dispersion strengthening effect after the brazing addition heat, in the core part of the aluminum alloy brazing sheet after the final cold rolling (before the brazing addition heat), 0.1 μm or more It is necessary to contain 20 / μm ² or more, more preferably 30 / μm ² or more of fine intermetallic compounds of less than 0.3 μm. In an aluminum alloy brazing sheet having a core part having such a metal structure, a large amount of intermetallic compounds remain in the part corresponding to the core material even after being subjected to brazing heat, so that a sufficient dispersion strengthening effect can be exhibited. it can. Here, the intermetallic compound of 0.1 μm or more in the core part of the aluminum alloy brazing sheet after the final cold rolling remains to some extent after the brazing heat, and can contribute to dispersion strengthening. The ultrafine intermetallic compound of less than 1 μm disappears by re-dissolving during brazing and cannot exert the effect of strengthening dispersion. When the density of the intermetallic compound of 0.1 μm or more and less than 0.3 μm contained in the core material portion after the final cold rolling is less than 20 / μm ² , the intermetallic compound remaining after brazing is small and sufficient The effect of dispersion strengthening cannot be obtained.

  In the brazing sheet of the present invention, the distribution density of the intermetallic compound in the core material portion is defined as described above in consideration of the above-described solid solution strengthening (and age hardening) and dispersion strengthening.

  Here, the density of the intermetallic compound is 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. 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.

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

In the aluminum alloy brazing sheet of the present invention, since the contents of Si and Mn of the core material are regulated to be relatively high, the core material portion is not used after the final cold rolling even if the conventional general manufacturing process is applied. It is possible to obtain a metal structure in which the density of intermetallic compounds of 0.1 μm or more and less than 0.3 μm is 20 / μm ² or more, but a sufficient amount of solid solution elements (mainly solid solution Mn In order to obtain the amount), as described above, the density of the intermetallic compound of 0.1 μm or more and less than 0.3 μm in the core portion after the final cold rolling is 100 / μm ² or less, more preferably 50 / μm ^2. In the following, it is necessary to simultaneously control the density of intermetallic compounds of 0.3 μm or more to be 1 piece / μm ² or less. In order to control excessive precipitation of intermetallic compounds in this way, During the manufacturing process In this case, it is necessary to control the heat applied in the above range, and in particular, precise control of temperature and time in 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, it is preferable to set the cooling rate at the time of casting 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 the homogenization treatment of the core material ingot is performed, the ingot heating temperature is set to 550 ° C. or more, so that the intermetallic compound in the core material ingot is re-dissolved and solidified after the homogenization treatment. It can use for a subsequent process as a state with much amount of melt | dissolution Mn. If the homogenization temperature exceeds 620 ° C, the ingot may be melted. Therefore, the homogenization 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”. Note that 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 an excessive amount of the intermetallic compound distribution cannot be obtained in the end, heating of the overlapping material before hot rolling is performed at 400 to 500 ° C. for 10 hours or less. 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, the material temperature in each stage, and the total time deviate from the above definition, it is difficult to obtain an appropriate intermetallic compound distribution. 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 to completely recrystallize at the stage before the final cold rolling, and to improve the formability and brazability 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 The intermetallic compound can be obtained in a fine state. 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. Precipitates excessively, making it difficult to obtain an appropriate intermetallic compound distribution. 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. The amount of dissolved Mn is large and the intermetallic compound can be in a fine state. 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%. The strain introduced by the final cold rolling tends to cause brazing diffusion during brazing, and the strength of the material is increased, which may hinder the subsequent forming process. 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 may be normally 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 intermetallic compounds can be suppressed, so that an appropriate distribution state of intermetallic compounds can be easily obtained.

  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, even if it is thin, it has high strength, creep resistance and good brazing properties. As an intercooler tube material that circulates compressed air with a turbocharger, it is a great merit that it can withstand high temperatures and high pressures 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. Also, when the sacrificial anode material is clad on one surface of the core material, the clad rate of the sacrificial anode material layer is not particularly limited, but it is usually 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. Furthermore, for each brazing sheet, the room temperature strength after brazing, the creep resistance after brazing, the fin joint ratio, the high temperature pressure resistance, the erosion resistance, the giant intermetallic compound, and the corrosion resistance were evaluated by the following methods. The results are shown in Table 6. In addition, regarding corrosion resistance, only those using a sacrificial anode material as the skin material were evaluated, and those not clad with a brazing material without using the sacrificial anode material were excluded.

(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) Room temperature strength after brazing:
After the brazing addition heat at 600 ° C. for 3 minutes, it was cooled at a cooling rate of 200 ° C./min. This sample was 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 listed in Table 6.

(3) Creep resistance 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 subjected to a creep test according to JIS Z2271 under the conditions of a temperature of 200 ° C. and a stress of 60 MPa. From the obtained results, the time required from the start of the creep test to the rupture is shown in Table 6.

(4) Fin joint ratio:
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. Table 6 shows that the test core has a fin joint ratio of 100% as “◯”, less than 100% and 95% or more as “Δ”, and less than 95% as “x”.

(5) High temperature pressure resistance evaluation:
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 fixed by being sandwiched between a pair of jigs 8 of a high-temperature pressure test apparatus as shown in FIG. 2 via a packing 9, from a hydraulic device (not shown) in the flat tube 1 of the test core 5. Oil 7 having a temperature of 150 ° C. was supplied through the pipe 6 under pressure, and a pressure (hydraulic pressure) of 0 to 300 kPa was applied into the flat tube 1. As a result, in Table 6, “◯” indicates that fin buckling due to tube deformation did not occur at 130 kPa or less, and “x” indicates that fin buckling occurred below 130 kPa.

(6) Erosion resistance:
After producing a test core similar to the high-temperature pressure resistance test under the same conditions as described above, cross-sectional micro observation was performed to confirm the occurrence of erosion. Table 6 shows “◯” when there is no erosion and “×” when there is erosion.

(7) 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 randomly sampled and observed at 10 pieces, and “○” indicates that a huge intermetallic compound having an equivalent circle diameter of 100 μm or more was not observed, and “×” indicates that it was observed. .

(8) Corrosion resistance evaluation:
Similar to the tensile test specimen, after the heat brazing 600 ° C. × 3 minutes, to seal the brazing material _{^{side, Cl - 500ppm, SO 4 2-}} 100ppm, 8 hours at a high temperature water of 88 ° C. containing Cu 2+ 10 ppm A cycle immersion test in which 16 hours at room temperature was set to 1 cycle was conducted for 3 months. “○” indicates that no corrosion penetration occurred, and “X” indicates that no corrosion penetration occurred.

As is clear from these tables, No. 1 as an example of the present invention. 1-No. 8, no. 13-No. 20, no. Examples 29 to 31 are the intermetallic compounds in which the alloy composition of the core material and the hot rolling conditions satisfy the conditions specified in the present invention, and the metal structure of the core material after the final rolling is 0.1 μm or more and less than 0.3 μm. The density of the intermetallic compound of 20 / μm ² or more and 100 / μm ² or less and 0.3 μm or more is 1 / μm ² or less. Satisfies.

  In contrast, no. 9-No. No. 12 is an example in which the alloy component of the core material does not satisfy the conditions specified in the present invention. No. 21-No. In No. 28, the alloy component of the core material satisfies the conditions specified in the present invention, but the manufacturing process conditions are not, and as a result, the conditions of the core metal structure are not. 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.

  Further, each of the inventive example and the comparative example will be examined in detail.

  As is apparent from Table 6, this is an example of the present invention, and the No. 1 satisfying the condition of the core metal structure as described above. 1-No. 5, no. 13-No. In Example 16, the tensile strength at room temperature after brazing is as high as 160 MPa or more, and it takes 100 hours or more from the start of the test to fracture in a creep test at 200 ° C. and 60 MPa, and the fin joint rate is 100%. Thus, it was confirmed that the test cores using these materials did not buckle the fins at 130 kPa or less even in a pressure test at a high temperature and had excellent heat resistance.

  In addition, No. containing Mg in the core material. 6-No. 8, no. In the inventive examples 17 to 20, the tensile strength at room temperature after brazing is 190 MPa or more, and in the creep test at 200 ° C. and 60 MPa, it is unbroken and has higher room temperature strength over 1000 hours. Creep resistance has been obtained, and the brazing property is 95% or more and less than 100%, which is inferior to the case where no Mg is added, but considering that the room temperature strength and creep resistance of the material are high. If so, the level was not particularly problematic. Moreover, the test core using these materials had excellent heat resistance without buckling of fins at 130 kPa or less in a pressure resistance test at a high temperature.

  Further, the present invention example No. 1-No. 8, no. 13-No. No. 20 material was excellent in erosion resistance, and no giant intermetallic compound of 100 μm or more was present, and it was confirmed that the material was suitable for use as a heat exchanger material.

  On the other hand, in the comparative example No. in which the alloy component of the core material does not satisfy the conditions specified in the present invention. 10-No. No. 12, the tensile strength at room temperature after brazing was less than 160 MPa, and in a creep test at 200 ° C. and 60 MPa, breakage occurred in less than 1000 hours. The test cores using these materials were subjected to a pressure test at a high temperature. The fin buckling occurred at less than 130 kPa.

  In addition, the core material does not contain Mg, and the manufacturing process deviates from the conditions specified in the present invention. 21-No. In the case of 24, the creep resistance was lower than that of the example of the present invention, and in the test core using these materials, fin buckling occurred at a pressure resistance test at a high temperature of less than 130 kPa.

  On the other hand, the core material contains Mg, and the manufacturing process deviates from the conditions specified in the present invention. 25-No. In the example No. 28, the creep life is not 1000 hours or more, the creep resistance is lower than the example of the present invention, and the fin joint ratio is 95% or more and less than 100%, but the creep life is less than 1000 hours. In this case, it can be said that the level is insufficient. Furthermore, the test cores using these materials showed fin buckling at a pressure resistance test at a high temperature of less than 130 kPa.

  Further, No. 1 having a high Si content, Fe content, and Mg content in the core material. 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. In the examples of 29 to 31, no corrosion penetration was observed, and the corrosion resistance was good. On the other hand, No. which is a comparative example. 32, no. In No. 33, corrosion penetration occurred and corrosion resistance was insufficient. No. 29-No. In Example 33, the tensile strength at room temperature after brazing is as high as 160 MPa or more, and the time required from the start of the test to rupture in the creep test at 200 ° C. and 60 MPa is 100 hours or more. It was confirmed that the material did not adversely affect the room temperature strength and creep resistance.

  From the above examples, the brazing sheet of the present invention is excellent in strength and creep resistance, has good brazing properties, does not contain a huge intermetallic compound, and has excellent productivity. It is clear that it is suitable for a tube material used under high temperature and high pressure such as a cooler.

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

Claims (9)

In 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 core aluminum alloy contains Si 0.3 to 1.2% (mass%, the same shall apply hereinafter), Fe 0.05 to 0.4%, Cu 0.3 to 1.2%, and Mn 0.8 to 1.8%. And further containing at least one selected from Ti 0.05 to 0.3%, Zr 0.05 to 0.3%, Cr 0.05 to 0.3%, V 0.05 to 0.3% And the balance is 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 20 / μm ² or more as the metal structure of the core part. pieces / [mu] m ² or less, moreover, wherein the distribution density of more intermetallic compounds 0.3μm is one / [mu] m ² or less, high heat resistance aluminum alloy brazing sheet. In the high heat resistant aluminum alloy brazing sheet according to claim 1,
The high heat-resistant aluminum alloy brazing sheet, wherein the aluminum alloy of the core material further contains Mg in an amount of 0.05 to 0.5% in addition to the component elements. In the high heat-resistant aluminum alloy brazing sheet according to any one of claims 1 and 2,
An Al—Si based brazing material is clad on one surface of the core material, a sacrificial anode material made of an Al—Zn based aluminum alloy is clad on the other surface of the core material, and the Al—Zn based aluminum alloy sacrificial anode material is Zn 1. A high heat-resistant aluminum alloy brazing sheet comprising 0.0 to 6.0%, Fe 0.05 to 0.4%, the balance being made of Al and inevitable impurities. In the high heat-resistant aluminum alloy brazing sheet according to claim 3,
Al— Zn- based aluminum alloy sacrificial anode material is Si 1.0% or less, Mn 1.8% or less, Ti 0.02 to 0.3%, V 0.02 to 0.3% in addition to the above-described component elements. A high heat-resistant aluminum alloy brazing sheet comprising at least one selected from the group consisting of: A method for producing an aluminum alloy brazing sheet according to claim 1 or claim 2;
A clad material obtained by superposing an Al-Si alloy brazing material on one side or both sides of a material for an aluminum alloy core material having the composition described in claim 1 or 2 and heating them, and performing hot rolling. A hot-clad rolling step, a cold-rolling step of cold-rolling the obtained clad material, and an intermediate-annealing step of 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, and performing intermediate annealing at a temperature within the range of 250 ° C. to 400 ° C. using a furnace of a batch-type, highly heat-resistant aluminum alloy brazing sheet manufacturing method of. A method for producing an aluminum alloy brazing sheet according to claim 1 or claim 2;
A clad material obtained by superposing an Al-Si alloy brazing material on one side or both sides of a material for an aluminum alloy core material having the composition described in claim 1 or 2 and heating them, and performing hot rolling. A hot-clad rolling step, a cold-rolling step of cold-rolling the obtained clad material, and an intermediate-annealing step of 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 method for producing a high heat-resistant aluminum alloy brazing sheet according to any one of claims 5 and 6,
A method for producing a high heat-resistant aluminum alloy brazing sheet, comprising performing a softening annealing step of heating to 200 to 400 ° C after the cold rolling step. A method for producing an aluminum alloy brazing sheet according to claim 1 or claim 2;
The aluminum alloy core material having the composition described in claim 1 or claim 2 is heated by superimposing an Al—Si alloy brazing material on one side or both sides and hot rolling to obtain a clad material. A hot-clad rolling step, a cold-rolling step of cold-rolling the obtained clad material, and a softening annealing step applied after the cold-rolling step,
In the hot clad rolling step, the thickness of the laminated material before hot clad rolling is 250 mm or more and 800 mm or less, and the 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. 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 to 300 ° C. or more and 400 ° C. or less, 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 process, the heating temperature is set within a range of 200 to 400 ° C., A method for producing a high heat-resistant aluminum alloy brazing sheet. In the method for producing a high heat-resistant aluminum alloy brazing sheet according to any one of claims 5 to 8,
The sacrificial anode material having the component composition according to any one of claims 3 and 4, wherein the Al-Si alloy brazing material is superposed on one surface of the core material, and the other surface of the core material is coated with the sacrificial anode material having the component composition according to any one of claims 3 and 4. A method for producing a high heat-resistant aluminum alloy brazing sheet, characterized by superposing and heating in that state for hot clad rolling.

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