JP4326906B2 - Manufacturing method of brazing sheet - Google Patents

Description

  The present invention relates to a method for producing a brazing sheet that requires high formability and brazing properties, such as plate materials for laminated evaporators, header plates such as radiators and heater cores, and tanks.

A heat exchanger such as a laminated evaporator is manufactured by forming a pipe line serving as a refrigerant circulation part by a pair of plate materials having an overhanging part and a drawing part and brazing together with fins that promote heat exchange. In addition, a header plate such as a radiator and a heater core, a tank, and the like are also subjected to predetermined steps including overhang and drawing, and then combined with a tube or the like to be integrated by brazing to obtain a product.
These plate material, header plate, tank, and the like are formed by stretching a brazing sheet. The brazing sheet is configured by bonding a brazing material made of an Al—Si based alloy to a core material made of an Al—Mn based alloy having high corrosion resistance and strength. For brazing, methods such as flux brazing using a non-corrosive flux or vacuum brazing are known.

By the way, the plate material and the header plate described above need excellent workability, and the elongation of the material is regarded as important. For this reason, the core material of the brazing sheet is a material that has been subjected to a homogenization treatment that is held at 530 ° C. or higher for 1 hour after casting, and is tempered with emphasis on elongation, for example, O material tempering, H2n tempering (in final annealing) Or a H1 tempered material (strain added after final annealing) or the like is used. Furthermore, in order to prevent brazing erosion of the low-working region introduced at the time of molding, which is a problem in the refining of the O material when considering brazing properties, a strain of 1 to 3% is added after the final annealing. In some cases (Patent Document 1).
Japanese Examined Patent Publication No. 6-47196

By the way, in order to cope with environmental problems such as energy saving and cost reduction due to weight reduction, it is necessary to increase the strength and reduce the thickness of the plate material. Conventionally, an AA3003 alloy or the like has been used for the core material of the brazing sheet, but recently, an aluminum alloy containing Cu or Si has been used, so that the thickness and strength can be increased. Further, a high corrosion resistance material in which Fe contained in the core material is reduced is also used.
However, in order to improve the performance of the heat exchanger, the molding of the plate material is more complicated and the processing degree is higher than the conventional one, and it is becoming difficult to form the conventional brazing sheet. Further, a material that simply emphasizes the elongation rate in order to improve the moldability may not have sufficient overhanging property, and a plate material having a complicated shape cannot be obtained.

As a result of the diligent research conducted by the inventors, it has been found that homogenization of the core material in several stages can simultaneously improve both the stretchability and the deep drawability and the brazing properties.
This invention is made | formed in view of the said situation, and it aims at providing the manufacturing method of the brazing sheet excellent in a moldability and brazing property.

In order to achieve the above object, the present invention employs the following configuration.
The method for producing a brazing sheet of the present invention is a method for producing a brazing sheet in which a brazing material made of an Al-Si alloy is bonded to one or both sides of a core material made of an aluminum alloy containing at least Mn, and the core material is formed. The aluminum alloy to be contained must contain 1.0 to 1.5% by mass of Mn, 0.05 to 0.8% by mass of Cu, 0.1 to 0.7% by mass of Fe, or both. And the balance is made of Al containing inevitable impurities, and the core material is initially homogenized under the condition of holding at a holding temperature of 560 to 610 ° C. for 3 to 10 hours and then cooling to 300 ° C. or lower. Subsequently, the homogenization treatment is performed at least once under the conditions of a holding temperature of 580 to 620 ° C. and a holding time of 3 to 12 hours, and the brazing material is stacked on one or both sides of the core material. After rolling, annealing is performed under conditions of a heating rate of 100 ° C./min or more and a holding temperature of 300 to 500 ° C., and after cooling at a cooling rate of 1800 ° C./min or less, 3 to 7% strain is introduced. It is characterized by that.

Further, the method for producing a brazing sheet of the present invention is a method for producing a brazing sheet in which a brazing material made of an Al-Si alloy is bonded to one or both sides of a core material made of an aluminum alloy containing at least Mn, and the core material The aluminum alloy that forms inevitably contains 1.0 to 1.5% by mass of Mn, and either 0.05 to 0.8% by mass of Cu or 0.1 to 0.7% by mass of Fe or The initial homogenization treatment is performed in such a condition that both of them are contained and the balance is made of Al containing inevitable impurities, and the core material is held at a holding temperature of 560 to 610 ° C. for 3 to 10 hours and then cooled to 300 ° C. or lower. Subsequently, this homogenization treatment under the conditions of a holding temperature of 580 to 620 ° C. and a holding time of 3 to 12 hours is performed at least once, and the brazing material is placed on one or both sides of the core material. After rolling after being repeated, initial annealing is performed under the conditions of a heating rate of 100 ° C./min or more and a holding temperature of 300 to 500 ° C., and after cooling to 180 ° C. or less, a heating rate of 0.2 ° C./min or more, Heating is performed at a holding temperature of 180 to 280 ° C., final annealing is performed at a cooling rate of 0.2 to 300 ° C./min, and strain of 3 to 7% is further introduced.

In addition, it is preferable that the said rolling performs cold rolling following hot rolling.
Further, the initial homogenization treatment and the main homogenization treatment are preferably performed after melting and casting the aluminum alloy and forming the core material into a sheet shape.

According to the above method for producing a brazing sheet, it is possible to promote the refining of crystal grains during recrystallization by annealing by previously performing a homogenization process on the core material. In particular, refinement of crystal grains can be further promoted by performing the homogenization treatment a plurality of times.
Furthermore, by performing the final annealing after the initial annealing, it is possible to further promote the precipitation of fine precipitates.
Furthermore, by introducing strain after the final annealing, brazing can be prevented and brazing can be improved.

Also, further aluminum alloy forming the core material, 0.1 to 0.8 mass% of Si, 0.01 to 0.2 wt% of Zr, 0.01 to 0.25 wt% of Ti, 0 Those containing at least one of 0.05 to 0.5% by mass of Mg are preferable.

  The strength of the brazing sheet can be increased by using the aluminum alloy having the above composition as the core material.

  Further, the Al—Si alloy forming the brazing material necessarily contains 5 to 15 mass% of Si, 5 mass% or less of Zn, 0.05 mass% or less of In, 0.2 mass% or less of Sn, What consists of Al which contains at least 1 sort (s) in 1.5 mass% or less of Mg, and the remainder contains an unavoidable impurity is preferable.

  By using the Al—Si alloy having the above composition as the brazing material, the corrosion resistance and brazing properties of the brazing sheet can be improved.

  Further, a sacrificial anode material made of an Al—Zn alloy is bonded to the other surface of the core material, and the Al—Zn alloy forming the sacrificial anode material always contains 5% by mass or less of Zn, and 2% by mass or less of Mg. 1 mass% or less Si, 1.5 mass% or less Mn, 0.2 mass% or less Zr, 0.2 mass% or less Ti, 0.05 mass% or less In, 0.2 mass% or less It may be made of Al containing at least one kind of Sn and the balance containing inevitable impurities.

  By using a sacrificial anode material made of an Al—Zn alloy having the above composition, the hardness and brazeability of the brazing sheet can be improved.

  As described above, according to the method for producing a brazing sheet of the present invention, a brazing sheet having excellent moldability and brazing properties can be produced.

Hereinafter, embodiments of the present invention will be described.
The brazing sheet according to the present invention is cold-rolled following hot rolling after a brazing material made of an Al-Si alloy is bonded to one or both sides of a core material made of an aluminum alloy containing at least Mn, and further annealed. Is made. The brazing sheet of the present invention may be one in which the brazing material is bonded to one surface of the core material and a sacrificial anode material made of an Al—Zn alloy is bonded to the other surface of the core material. The core material constituting the brazing sheet is tempered with O material, and a recrystallized structure is formed in most parts by heat treatment during brazing.

(Composition of heartwood)
Next, the reason for limiting the composition of the aluminum alloy constituting the core material of the brazing sheet according to the present invention will be described.
Manganese (Mn) is an essential element and forms an intermetallic compound together with Fe, Si, and Al, and becomes a crystallization phase and a precipitation phase to improve the strength of the core material after brazing. Further, the potential of the core material is made noble to improve the pitting corrosion resistance not only on the sacrificial anode material side but also on the brazing material side. If the Mn content is less than 1.0% by mass, desired strength and pitting corrosion resistance cannot be obtained. On the other hand, if the Mn content exceeds 1.5% by mass, it becomes brittle and the workability such as rolling deteriorates. Therefore, the appropriate content of Mn is set to 1.0 to 1.5% by mass.

Copper (Cu) improves the strength of the brazing sheet after brazing by dissolving in Al. Further, the potential of the core material is made noble to improve the pitting corrosion resistance not only on the sacrificial anode material side but also on the brazing material side. When the Cu content is less than 0.05%, these effects are poor, and when the Cu content exceeds 0.8%, the melting point of the core material decreases and the core melts during brazing. Therefore, the proper content of Cu is set to 0.05 to 0.8%.
Iron (Fe) forms an intermetallic compound together with Si and Al, and becomes a crystallization phase and a precipitation phase to improve the strength of the brazing sheet after brazing. Further, recrystallization is promoted in the annealing process and the brazing process. If the Fe content is less than 0.1%, these effects are poor. On the other hand, if the Fe content exceeds 0.7%, the corrosion rate becomes excessive, and the crystal grains in the annealing process become too small. Sometimes, erosion due to wax is significantly increased in parts where processing is not introduced. Therefore, the proper content of Fe is set to 0.1 to 0.7%.
Note that either Fe or Cu may be included in the core material, or both may be included.

The core material may contain at least one of Si, Zr, Ti, and Mg.
Silicon (Si) forms an Al—Mn—Si compound together with Al and Mn, exerts solid solution hardening, precipitation hardening, and dispersion hardening action, and improves the strength of the core material. If the Si content is less than 0.1%, the strength of the core material cannot be increased. On the other hand, if the Si content exceeds 0.8%, it diffuses together with Mg to the sacrificial anode material side, increasing the intergranular corrosion sensitivity of the sacrificial anode material. Therefore, the appropriate content of Si is set to 0.1 to 0.8%.

  Zirconium (Zr) and titanium (Ti) form a fine intermetallic compound after brazing, exert a dispersion hardening action, and improve the strength of the core material. If the Zr content is less than 0.01%, the strength of the core material cannot be sufficiently increased. On the other hand, if the Zr content exceeds 0.2%, the workability deteriorates. In the case of Ti, if the Ti content is less than 0.01%, the strength of the core material cannot be sufficiently increased. On the other hand, if the Ti content exceeds 0.25%, the workability deteriorates. Therefore, the proper content of Zr is set to 0.01 to 0.2%, and the proper content of Ti is set to 0.01 to 0.25%.

Magnesium (Mg) is dissolved in the matrix to improve the strength of the core material. Further, Mg forms Si diffused from the brazing material and Si and Mg ₂ Si compound simultaneously added to the core material to improve the strength of the core material. If the Mg content is less than 0.05%, the strength of the core cannot be increased. On the other hand, if the Mg content exceeds 0.5%, it diffuses to the sacrificial anode material side together with Si to increase the intergranular corrosion sensitivity of the sacrificial anode material and inhibit brazing. Therefore, the appropriate content of Mg is set to 0.05 to 0.5%.

(Composition of brazing material)
Next, the reason for limiting the composition of the Al—Si alloy constituting the brazing material of the brazing sheet according to the present invention will be described.
Silicon (Si) is an essential element, and a brazing material is melted and fluidized during brazing to form a joint. When the Si content is less than 5%, the fluidity of the brazing material is lowered, and when the Si content exceeds 15%, erosion of the core material or the splicing member is increased. Therefore, the appropriate content of Si is set to 5 to 15%.

Zinc (Zn) improves the corrosion resistance by forming a potential distribution effective for preventing corrosion from the brazing material surface to the core material by lowering the potential of the brazing material. If the Zn content exceeds 5%, the self-corrosion rate becomes excessive. Therefore, the proper content of Zn is set to 5% by mass or less.
Indium (In) and tin (Sn) lower the potential of the brazing material and improve the sacrificial anode effect of the brazing material. Even when the In content exceeds 0.05%, the sacrificial anode effect is not improved. Similarly, in the case of Sn, the sacrificial anode effect is not improved even if the content exceeds 0.2%. Therefore, the proper content of In is set to 0.05% by mass or less, and the proper content of Sn is set to 0.2% or less.
Magnesium (Mg) is preferably added when vacuum brazing is performed, and brazing improves when added. If the Mg content exceeds 1.5%, the brazing property is impaired, and the workability of the brazing material is lowered. Therefore, the appropriate content of Mg is set to 1.5% by mass or less.
Any one or more of Zn, In, Sn, and Mg may be included in the brazing material.

(Composition of sacrificial anode material)
Next, the reason for limiting the composition of the Al—Zn alloy constituting the sacrificial anode material of the brazing sheet according to the present invention will be described.
Zinc (Zn) is an essential element, and improves the corrosion resistance by forming a potential distribution effective from the surface of the sacrificial anode material to the core material for preventing corrosion from the potential of the sacrificial anode material. If the Zn content exceeds 5%, the self-corrosion rate becomes excessive. Therefore, the proper content of Zn is set to 5% by mass or less.

Magnesium (Mg) improves the strength of the sacrificial anode material by forming precipitates such as ZnZn and Si simultaneously added to the sacrificial anode material after brazing and Si diffused from the core material and MgZn ₂ and Mg ₂ Si. . If the Mg content exceeds 2%, it becomes brittle and the rolling processability decreases. Therefore, the appropriate content of Mg is set to 2% or less.
Silicon (Si) forms precipitates such as Mg simultaneously added to the sacrificial anode material after brazing, Mg diffused from the core material, and Mg ₂ Si, thereby improving the strength of the sacrificial anode material. If the Si content exceeds 1%, the melting point of the sacrificial anode material is lowered and melts during brazing. Therefore, the appropriate content of Si is set to 1% or less.

Manganese (Mn) forms an intermetallic compound together with Si and Al, and becomes a crystallization phase and a precipitation phase, thereby improving the strength of the sacrificial anode material after brazing. Moreover, the sacrificial anode material is made noble and the pitting corrosion resistance is improved. If the Mn content exceeds 1.5% by mass, it becomes brittle and the workability such as rolling deteriorates. Therefore, the proper content of Mn is set to 1.5% by mass or less.
Zirconium (Zr) and titanium (Ti) form a fine intermetallic compound after brazing, exert a dispersion hardening action, and improve the strength of the sacrificial anode material. If the Zr content and the Ti content each exceed 0.2%, workability deteriorates. Accordingly, the proper contents of Zr and Ti are each set to 0.2% or less.
Indium (In) and tin (Sn) lower the potential of the sacrificial anode material and improve the sacrificial anode effect of the brazing material. Even when the In content exceeds 0.05%, the sacrificial anode effect is not improved. Similarly, in the case of Sn, the sacrificial anode effect is not improved even if the content exceeds 0.2%. Therefore, the proper content of In is set to 0.05% by mass or less, and the proper content of Sn is set to 0.2% or less.
Note that one or more of Mg, Si, Mn, Zr, Ti, In, and Sn may be included in the sacrificial anode material.

(First embodiment)
Next, the manufacturing method of the brazing sheet of the 1st Embodiment of this invention is demonstrated.
In the manufacturing method of the brazing sheet of the present embodiment, a core material is obtained by melting and casting an aluminum alloy having a composition in the above appropriate range, and the core material is homogenized. In addition, a brazing material is obtained by melting and casting an Al—Si alloy having a composition in the above appropriate range, and the brazing material is homogenized and hot-rolled as necessary. Next, a brazing material is bonded to one or both sides of the core material, and hot rolling is followed by cold rolling to obtain a clad material. The clad material is annealed and further strained to obtain a desired brazing sheet.

  The homogenization treatment for the core material is performed by initial homogenization treatment under the condition of holding at a holding temperature of 560 to 610 ° C. for 3 to 10 hours and then cooling to 300 ° C. or lower, followed by a holding temperature of 580 to 620 ° C. This homogenization treatment under the condition of 12 hours is performed at least once. The multistage homogenization process can remarkably accelerate the recrystallization of the core material, and can improve the stretchability by increasing the elongation of the brazing sheet. The homogenization step may be performed any number of times as long as it is performed once or more. If the homogenization treatment is insufficient, the stretchability of the brazing sheet is lowered. Moreover, when homogenization is performed excessively, recrystallization is promoted too much and the anisotropy is lowered, the ear ratio is lowered, and the overhanging property is deteriorated. Moreover, if the holding temperature of this homogenization process exceeds 620 degreeC, a core material will fuse | melt. Furthermore, if it is not cooled to 300 ° C. in the initial homogenization treatment, the initial homogenization is excessively performed, the recrystallization is promoted too much, and the anisotropy is lowered, thereby lowering the stretchability. Therefore, the homogenization conditions were as described above.

  Next, the annealing process after rolling is performed by continuous annealing (CAL) under the conditions of a heating rate of 100 ° C./min or more and a holding temperature of 300 to 500 ° C. By setting the heating rate to 100 ° C./min or more, the crystal grains are refined to improve the overhanging property, and the deterioration of the overhanging property after introducing strain is prevented. That is, by miniaturizing the crystal grains, the low processing area where the wax erosion occurs can be reduced, the amount of strain to be introduced can be reduced, and the formability (particularly the stretchability) is not lowered. When the heating rate is less than 100 ° C./min, the crystal grains become coarse and the stretchability is lowered, and recrystallization is delayed, so that erosion due to melting wax occurs even if strain is added in a later step.

  Further, by setting the holding temperature to 300 to 500 ° C., the recrystallization can be performed completely, and the stretchability is improved by increasing the elongation rate. When the holding temperature is less than 300 ° C., recrystallization is incomplete and the stretchability is lowered. On the other hand, when the holding temperature exceeds 500 ° C., the additive element is excessively dissolved, and the deep drawability is deteriorated. The holding time of the holding temperature is preferably in the range of several seconds to 3 hours.

  Moreover, it is preferable to cool a clad material to 150 degrees C or less at the cooling rate of 1800 degrees C / min or less after progress of holding time. By cooling, precipitation of fine precipitates having an average particle diameter of 0.01 to 0.1 μm can be promoted, and deep drawability can be improved. When the cooling rate exceeds 1800 ° C./min, the precipitation of fine precipitates does not proceed and the deep drawability deteriorates. On the other hand, if the cooling rate is less than 0.2 ° C., the productivity of the brazing sheet is greatly reduced.

Next, 3-7% strain is introduced after annealing. The introduction of strain is to reduce the plate thickness of the clad material, and is performed by, for example, a tension leveler, stretcher, skin pass rolling, roller beller or the like. The strain amount is given by (t ₁ −t ₂ ) / t ₁ × 100 (%), where t ₁ is the thickness of the clad material before strain introduction and t ₂ is the thickness after strain introduction.
In the present invention, the strain amount is preferably 3 to 7%. By introducing strain, strain is also added to a low processing area where brazing erosion may occur, thereby improving brazability. In addition, by appropriately introducing strain, excessive elongation of the brazing sheet is prevented and the moldability is improved. When the amount of strain is less than 3%, the core material does not recrystallize due to the heat treatment during brazing, and Si contained in the brazing material penetrates into the sub-grain boundaries of the core material, resulting in brazing corrosion and brazing properties. descend. On the other hand, when the strain amount exceeds 7%, the brazing sheet is fully extended in the strain introduction process, and the overhanging property when the plate material is formed from the brazing sheet is lowered.

  As described above, recrystallization of the core material in the annealing process can be remarkably promoted by performing homogenization a plurality of times. Thereby, the crystal grain diameter of O material refining can be remarkably refined, and the stretchability can be improved as well as the elongation rate of the brazing sheet is improved. Thereby, even if a strain of 3 to 7% is introduced after annealing, there is little decrease in the stretchability.

(Second Embodiment)
Next, the manufacturing method of the brazing sheet of the 2nd Embodiment of this invention is demonstrated.
In this embodiment of the brazing sheet manufacturing method, a core material is obtained by melting and casting an aluminum alloy having a composition in the appropriate range, and the core material is homogenized. In addition, a brazing material is obtained by melting and casting an Al—Si alloy having a composition in the above appropriate range, and the brazing material is homogenized and hot-rolled as necessary. Next, a brazing material is bonded to one or both sides of the core material, and hot rolling is followed by cold rolling to obtain a clad material. By performing initial annealing and final annealing on the clad material and further introducing strain, a desired brazing sheet can be obtained.

  The homogenization step and the strain introduction step for the core material in the present embodiment are performed under the same conditions as the respective steps in the first embodiment. Only the initial annealing process and the final annealing process will be described.

The initial annealing step in this embodiment is performed by continuous annealing (CAL) under the conditions of a heating rate of 100 ° C./min or more and a holding temperature of 300 to 500 ° C. By setting the heating rate to 100 ° C./min or more, the crystal grains are refined to improve the overhanging property, and the deterioration of the overhanging property after introducing strain is prevented. That is, by miniaturizing the crystal grains, the low processing area where the wax erosion occurs can be reduced, the amount of strain to be introduced can be reduced, and the formability (particularly the stretchability) is not lowered. When the heating rate is less than 100 ° C./min, the crystal grains become coarse and the stretchability is lowered, and recrystallization is delayed, so that erosion due to melting wax occurs even if strain is added in a later step.
Further, by setting the holding temperature to 300 to 500 ° C., the recrystallization can be performed completely, and the stretchability is improved by increasing the elongation rate. When the holding temperature is less than 300 ° C., recrystallization is incomplete and the stretchability is lowered. On the other hand, when the holding temperature exceeds 500 ° C., the additive element is excessively dissolved in the solution and the deep drawability is lowered. The holding time of the holding temperature is preferably in the range of several seconds to 3 hours. Further, it is preferable to cool the clad material to 180 ° C. or lower before moving from the initial annealing step to the final annealing step. This is because the initial annealing holding temperature is higher than the final annealing holding temperature, and if the final annealing process is started without cooling, the initial annealing process is excessively performed.

Next, the final annealing step is performed by batch annealing treatment or continuous annealing treatment (CAL) under conditions of a heating rate of 0.2 ° C./min or more, a holding temperature of 180 to 280 ° C., and a cooling rate of 0.2 to 300 ° C./min. Do. The final annealing step promotes the precipitation of fine precipitates having an average particle size of 0.01 to 0.1 μm and improves deep drawability. If the final annealing is insufficient, that is, if the heating rate is less than 0.2 ° C./min or the holding temperature is less than 180 ° C., the precipitate becomes coarse and the deep drawability deteriorates. On the other hand, when the holding temperature exceeds 280 ° C., the additive element is excessively dissolved, and the deep drawability is lowered.
Further, when the cooling rate is 0.2 to 300 ° C./min, precipitation of fine precipitates having an average particle diameter of 0.01 to 0.1 μm is promoted. If the cooling rate is less than 0.2 ° C./min, the precipitates become coarse and the deep drawability deteriorates. If the cooling rate exceeds 300 ° C./min, the additive element excessively dissolves and the deep drawability deteriorates. Furthermore, the holding time of the holding temperature is preferably in the range of 0 hour to 5 hours.

  As mentioned above, a brazing sheet can be made into O material refining by performing initial annealing and final annealing after rolling. Moreover, precipitation of a fine precipitate can be accelerated | stimulated by providing the final annealing process with a heating rate smaller than an initial annealing process after an initial annealing process. Thereby, the moldability of the brazing sheet such as deep drawability and stretchability can be enhanced.

  In the above description of the method for producing a brazing sheet, an example in which a brazing material is bonded to one surface or both surfaces of a core material to form a brazing sheet has been described, but the present invention is not limited thereto, and a brazing material is applied to one surface of the core material. It is good also as a brazing sheet | seat by bonding together and a sacrificial anode material together on the other surface.

(Experimental example 1)
After melting and casting the aluminum alloy, initial homogenization and main homogenization were performed, and then cold rolling was performed to prepare a core material having a thickness of 160 mm. In addition, the frequency | count of this homogenization was 1 time.
Also, after melting and casting the Al—Si alloy, homogenization was carried out under the conditions of a heating rate of 1 ° C./min, a holding temperature of 500 ° C., and a holding time of 540 minutes, thereby preparing a brazing material having a thickness of 20 mm.

Next, a brazing material was bonded to both sides of the core material, followed by hot rolling and cold rolling to obtain a clad material having a thickness of 0.5 mm. The clad material was annealed, and strains were introduced by rolling to obtain brazing sheets of Examples 1 to 5 and Comparative Examples 1 to 11.
The obtained brazing sheet was subjected to an Erichsen test, and the Eriksen value was measured. The conditions of the Eriksen test were as follows: the size of the sample piece was a square plate of 90 mm square and a thickness of 0.5 mm, the wrinkle holding force was 10 kN, and the punch tip shape was a grain surface with an outer diameter of 20 mm.

  Moreover, the deep drawing test was done with respect to the obtained brazing sheet, and the limit drawing ratio was measured. The conditions of the deep drawing test were as follows: a sample piece having a size of 90 mm square and a thickness of 0.5 mm square plate, a wrinkle holding force of 3 kN, a punch shape of 30 mm in diameter and a shoulder R4.5 mm cylinder, The dimensions were an outer diameter of 34 mm and a shoulder R 4.5 mm. Furthermore, beef tallow was applied to both sides of the sample piece as a lubricating oil.

Moreover, the drop test was performed with respect to the obtained brazing sheet, and the flow coefficient of the brazing material with respect to the core material was measured.
If a rectangular blazing sheet having a length of 100 mm and a width of 25 mm is placed vertically and left in an atmosphere at 600 ° C. for 3 minutes, a part of the brazing material flows down toward the lower side of the blazing sheet, causing the brazing. A brazing material reservoir is formed below the sheet. When the weight of the entire brazing sheet before heating is W0 and the weight of the lower quarter of the brazing sheet after heating including the brazing material reservoir is Wb, the flow coefficient Kd is
Kd = (4Wb−W0) / (3W0 × cladding rate)
Calculated with The cladding rate is the ratio of the brazing material thickness to the plate thickness.

  Table 1 shows the alloy composition of the core material and the brazing material, Table 2 shows the homogenization condition of the core material, the annealing condition of the cladding material, and the strain amount, respectively, and Table 3 shows the Erichsen value, the limit drawing ratio, and the flow coefficient.

As shown in Table 3, the brazing sheets of Examples 1 to 5 have Erichsen values in the range of 8.2 to 8.5, which are higher than those of Comparative Examples 1 to 11. From this, it can be seen that Examples 1 to 5 are excellent in overhang property.
In addition, the brazing sheets of Examples 1 to 5 have a limit drawing ratio in the range of 2.14 to 2.16, which is higher than those of Comparative Examples 1 to 11. This shows that Examples 1-5 are excellent also in deep drawability.

  Furthermore, the brazing sheets of Examples 1 to 5 have a flow coefficient in the range of 0.53 to 0.54, which is higher than those of Comparative Examples 1 to 11. Therefore, about Examples 1-5, it turns out that the fluidity | liquidity of a brazing material is high and it is excellent in brazing property.

  On the other hand, Comparative Example 1 has a high cooling temperature during homogenization, Comparative Example 2 has a low initial homogenization holding speed, Comparative Example 3 has a low homogenization holding temperature, and Comparative Example 4 has a low temperature. The homogenization holding temperature was high, and for Comparative Example 5, the initial homogenization holding temperature was high, and for Comparative Example 6, the initial homogenization holding temperature was higher than the main homogenization holding temperature. It seems that the coefficient was lower than in Examples 1-5.

  Moreover, since the heating rate of annealing was low for Comparative Example 7, the holding temperature for annealing was low for Comparative Example 8, and the holding temperature for annealing was high for Comparative Example 9, the Erichsen value, the limit drawing ratio, and the flow coefficient were It seems to have fallen.

  Furthermore, since the strain amount was small for Comparative Example 10 and the strain amount was large for Comparative Example 11, it seems that the Eriksen value, the limit drawing ratio, and the flow coefficient were lower than those of Examples 1-5.

(Experimental example 2)
After melting and casting the aluminum alloy, initial homogenization and main homogenization were performed, and then cold rolling was performed to prepare a core material having a thickness of 160 mm. In addition, the frequency | count of this homogenization was 1 time.
Further, after melting and casting the Al—Si alloy, homogenization was performed under the conditions of a heating rate of 1 ° C./min, a holding temperature of 510 ° C., and a holding time of 540 minutes, thereby preparing a brazing material having a thickness of 20 mm.

  Next, a brazing material was bonded to both sides of the core material, followed by hot rolling and cold rolling to obtain a clad material having a thickness of 0.5 mm. The brazing sheets of Examples 6 to 10 and Comparative Examples 12 to 18 were obtained by sequentially performing initial annealing and final annealing on the clad material, and further introducing strain by rolling.

For the obtained brazing sheet, the Erichsen value, the limit drawing ratio and the flow coefficient were measured in the same manner as in Experimental Example 1.
Table 4 shows the alloy composition of the core material and the brazing material, Table 5 shows the homogenization condition of the core material, the annealing condition of the clad material, and the strain amount, respectively, and Table 6 shows the Erichsen value, the limit drawing ratio, and the flow coefficient.

As shown in Table 6, the brazing sheets of Examples 6 to 10 have an Erichsen value in the range of 8.3 to 8.5, which is higher than those of Comparative Examples 1 to 18. From this, it can be seen that Examples 6 to 10 are excellent in overhang property.
In addition, the brazing sheets of Examples 6 to 10 have a limit drawing ratio in the range of 2.15 to 2.16, which is higher than those of Comparative Examples 1 to 18. This shows that Examples 6-10 are excellent also in deep drawability.

  Furthermore, the brazing sheets of Examples 6 to 10 have a flow coefficient in the range of 0.53 to 0.55, which is higher than those of Comparative Examples 1 to 18. Therefore, about Examples 6-10, it turns out that the fluidity | liquidity of a brazing material is high and it is excellent in brazing property.

  On the other hand, the heating rate of the initial annealing is low for the comparative example 12, the holding temperature for the initial annealing is low for the comparative example 13, the holding temperature for the initial annealing is high for the comparative example 14, and the final annealing is held for the comparative example 15 Since the temperature was low and the holding temperature of final annealing was high for Comparative Example 16, it seems that the Erichsen value, the limit drawing ratio, and the flow coefficient were lower than those of Examples 6-10.

Furthermore, since the strain amount was small for Comparative Example 17 and the strain amount was large for Comparative Example 18, it seems that the Erichsen value, the limit drawing ratio, and the flow coefficient were lower than those of Examples 6-10.

Claims (5)

It is a method for producing a brazing sheet in which a brazing material made of an Al-Si alloy is bonded to one or both sides of a core material made of an aluminum alloy containing at least Mn,
The aluminum alloy forming the core material necessarily contains 1.0 to 1.5% by mass of Mn, and is either 0.05 to 0.8% by mass of Cu or 0.1 to 0.7% by mass of Fe. One or both, and the balance is made of Al containing inevitable impurities,
The core material is subjected to an initial homogenization treatment under the condition of holding at a holding temperature of 560 to 610 ° C. for 3 to 10 hours and then cooling to 300 ° C. or lower, followed by a holding temperature of 580 to 620 ° C. The homogenization process under the conditions is performed at least once,
After rolling the brazing material on one side or both sides of the core material, rolling is performed, and then annealing is performed at a heating rate of 100 ° C./min or more and a holding temperature of 300 to 500 ° C. at a cooling rate of 1800 ° C./min or less. A method for producing a brazing sheet characterized by introducing a strain of 3 to 7% after cooling. It is a method for producing a brazing sheet in which a brazing material made of an Al-Si alloy is bonded to one or both sides of a core material made of an aluminum alloy containing at least Mn,
The aluminum alloy forming the core material necessarily contains 1.0 to 1.5% by mass of Mn, and is either 0.05 to 0.8% by mass of Cu or 0.1 to 0.7% by mass of Fe. One or both, and the balance is made of Al containing inevitable impurities,
The core material is subjected to an initial homogenization treatment under the condition of holding at a holding temperature of 560 to 610 ° C. for 3 to 10 hours and then cooling to 300 ° C. or lower, followed by a holding temperature of 580 to 620 ° C. The homogenization process under the conditions is performed at least once,
After rolling the brazing material on one or both sides of the core material, after rolling, initial annealing is performed at a heating rate of 100 ° C./min or more and a holding temperature of 300 to 500 ° C., and after cooling to 180 ° C. or less In addition to heating at a heating rate of 0.2 ° C./min or more and a holding temperature of 180 to 280 ° C., final annealing is performed at a cooling rate of 0.2 to 300 ° C./min, and further 3 to 7%. A method for producing a brazing sheet, wherein distortion is introduced. The aluminum alloy forming the core material further includes 0.1 to 0.8% by mass of Si, 0.01 to 0.2% by mass of Zr, 0.01 to 0.25% by mass of Ti, 0.05 to The method for producing a brazing sheet according to claim 1 , comprising at least one of 0.5% by mass of Mg. The Al—Si alloy forming the brazing material necessarily contains 5 to 15 mass% of Si, Zn of 5 mass% or less, In of 0.05 mass% or less, Sn of 0.2 mass% or less, 1. The at least 1 sort (s) of 5 mass% or less Mg is contained, and the remainder consists of Al containing an unavoidable impurity, The any one of Claims 1-3 characterized by the above-mentioned. Manufacturing method of brazing sheet A sacrificial anode material made of an Al—Zn alloy is bonded to the other surface of the core material, and the Al—Zn alloy forming the sacrificial anode material always contains 5% by mass or less of Zn, 2% by mass or less of Mg, 1% % By mass Si, 1.5% by mass or less Mn, 0.2% by mass or less Zr, 0.2% by mass or less Ti, 0.05% by mass or less In, 0.2% by mass or less Sn The method for producing a brazing sheet according to any one of claims 1 to 4 , wherein at least one of them is contained, and the balance is made of Al containing inevitable impurities.