JP5982102B2 - Clad material for cooler and cooler for heating element - Google Patents

Description

  The present invention is mounted on an electric vehicle, a hybrid vehicle, various electronic device circuits, and the like, and uses, for example, a clad material for a cooler applied to a cooler that cools a heating element such as a semiconductor element, and the clad material for this cooler. The present invention relates to a heat generating element cooler.

An electric vehicle, a hybrid vehicle, and various electronic device circuits are equipped with a cooler for cooling a heating element such as a semiconductor element.
Such a cooler includes a top plate made of an aluminum alloy plate to which an object to be cooled is attached, a bottom plate made of an aluminum alloy plate that defines a passage of cooling water between the top plate, and these aluminum alloy plates. A so-called water-cooling type is known in which inner fins housed between each other are brazed to each other, and the object to be cooled is cooled by heat exchange between the cooling water flowing in the cooling water passage and the object to be cooled. It has been.
In this cooler, in order to improve the heat exchange efficiency between the cooling water and the cooled object, the top plate to which the cooled object is attached is formed sufficiently thinner than the bottom plate. Further, in recent years, an apparatus in which an insulating circuit substrate (cooling element substrate) to which a semiconductor element (cooled body) is bonded is attached to the top plate has been developed. This insulating circuit board is obtained by bonding a metal plate such as pure aluminum on both sides of heat conductive insulating ceramics such as AlN and Si ₃ N ₄ and brazing the insulating circuit board integrally with the heat exchanger. It has also been done.
When brazing the top plate and the bottom plate made of aluminum alloy in the above-mentioned cooler, after applying fluoride flux (for example, non-corrosive Nocolok flux or Zn substitution flux), assemble into heat exchanger shape Thereafter, brazing is performed by heating to about 590 ° C. to 620 ° C. in a high purity nitrogen gas atmosphere.

By the way, with the recent increase in environmental orientation, the weight of automobiles has been reduced, and the components mounted on the coolers mounted thereon are also becoming thinner. On the other hand, the calorific value of semiconductor elements and the like is larger, and a larger cooling performance is required for a cooler that cools the semiconductor element.
In such a background, as described in Patent Document 1 below, a semiconductor element is attached to a thin heat sink through a metal plate, and the heat sink is divided into a plurality of refrigerant passages by a partition wall. A structure of a cooler configured as described above is known.

  Here, in order to improve the cooling performance of this type of cooler, it is necessary to flow cooling water. However, when cooling water is flowed, it becomes a severe corrosive environment for the components of the cooler. Especially on a thin top plate, corrosion from the cooling water passage side penetrates the plate thickness direction, and corrosion holes are formed early. Will be. For this reason, in order to achieve the thinning of the cooler and the improvement of the cooling performance at the same time, it is essential to improve the corrosion resistance of the top board.

JP 2010-16295 A

However, the material for the top plate of the conventional cooler is difficult to improve the corrosion resistance because of the balance with the moldability, and when it is configured to flow cooling water, it is not enough to improve the corrosion resistance of the thin top plate. Is the actual situation.
That is, in the cooler as described above, for example, a clad material in which an Al—Si brazing material is clad on at least one surface (surface on the cooling water passage side) of an aluminum alloy plate is used as a top plate material. A product obtained by press-molding this into a predetermined shape is used as the top plate.
However, due to the above-mentioned background of weight reduction of automobiles, the heat exchanger material is being made thinner, and when the heat generation amount of the cooling element is large, the flow rate of cooling water is improved to improve the cooling performance. The corrosive environment of heat exchanger materials has become increasingly severe. Furthermore, the pressure of the cooling water applied to the heat exchanger is gradually increased, and the material strength is also required as the heat exchanger material is made thinner.
By the way, the above clad material is processed into the shape of a heat exchanger by brazing and brazed, but when the shape of the heat exchanger is complicated, the elongation is large and the strength is suitable for press molding. Therefore, an O material specified by the quality JIS standard in which the wrought material is annealed is often selected.

 However, if the grade O material is simply press-formed, recrystallization will be incomplete and sub-crystal grains will remain in the region where the amount of processing is small. Invasion, so-called erosion occurs.

When the brazing material erodes the core material, a part of the brazing material is consumed, so that the amount of the brazing material used for brazing is insufficient, and there is a disadvantage that sufficient joint strength cannot be obtained.
Further, since corrosion progresses preferentially from the eutectic portion of the brazing material structure, if the core material is eroded by the brazing material, there is a possibility that the corrosion proceeds in the depth direction at an early stage. Even if this brazing erosion has arranged the sacrificial material on the inner surface side of the core material, if the corrosion progresses in the depth direction, when the corrosion reaches the outer brazing erosion part, it becomes a through hole at an early stage, It tends to be a problem in terms of corrosion resistance.

The above clad material is press-molded to the desired shape, and then the cooling element (insulation circuit board) is temporarily fixed by laser welding or the like, and another clad material (clad material clad with brazing material on the inner surface) or inner fin After the combination, the butt portion is temporarily fixed by laser welding and brazed. However, if excessive heat input is applied by laser welding and the melted area is widened, the laser welded part becomes electrochemically baseless, and through holes are generated early due to corrosion. It is necessary to temporarily fix it while keeping it as small as possible.
Furthermore, since aluminum reflects the laser at its surface, it has a problem that it melts rapidly in the initial stage of welding and the heat input becomes excessive.

 The present invention has been made to solve these problems, has good press formability, can be accurately molded into the shape of the top plate of the cooler, and other parts constituting the cooler. A sufficient amount of brazing material can be supplied for brazing, and a clad material for a cooler that exhibits excellent corrosion resistance as a top plate and suppresses the generation of corrosion holes, and a clad material for this cooler. An object of the present invention is to provide a cooler for a heating element used.

 As a result of studies conducted by the present inventors to improve the press formability, laser weldability, brazing property, and corrosion resistance of the clad material that is a material for the top plate, including a core material made of O material according to quality, Even if it is another O material, it is understood that it is necessary to suppress the brazing erosion behavior of the clad material while suppressing the brazing erosion behavior to a minimum and forming a potential gradient advantageous for corrosion prevention in the clad material after brazing. In order to suppress the erosion behavior of the brazing to a minimum, it has been found that it is effective to appropriately adjust the Fe content of the brazing filler metal, the particle size of the Si particles, and the crystal grain size of the core material. The present invention has been made based on such findings and has the following configuration.

The clad material for a cooler according to the present invention has a core material, a first brazing material layer covering one surface of the core material, and a second brazing material layer covering the other surface of the core material. A clad material having a three-layer structure, which is a graded O material , and is a clad material for a cooler that constitutes a working fluid passage of a heat generating element cooler together with an aluminum alloy material. A clad material for a cooler that is brazed with the brazing filler metal layer side as a working fluid passage side, wherein the core material contains Mn, Cu, Si, Fe in the following contents, or further Ti, Zr 1 type or 2 types or more selected from among them are contained in the following content, and the balance is composed of an aluminum alloy composed of Al and inevitable impurities,
Mn: 0.4 to 1.5 mass%, Cu: 0.05 to 0.8 mass%, Si: 0.05 to 1.0 mass%, Fe: 0.05 to 0.5 mass%, Ti: 0.05-0.20% by mass, Zr: 0.05-0.15% by mass, the first brazing material layer contains Si, Zn, and Fe in the following contents, and the balance is inevitable with Al. It is comprised by the aluminum alloy brazing material which consists of impurities, Si: 4.5-11.0 mass%, Zn: 2.5-6.0 mass%, Fe: 0.1-0.2 mass%,
The second brazing filler metal layer contains Si and Fe in the following contents, and the balance is composed of an aluminum alloy brazing filler metal composed of Al and inevitable impurities. Si: 5.0 to 12.6 mass% Fe: 0.1 to 0.7 mass%, before brazing with the aluminum alloy material constituting the cooler, the elongation is 15% or more, and the average crystal grain size in the rolling direction of the rolling direction parallel section is 80 ˜500 μm, the average crystal grain size in the plate thickness direction is 30 to 100 μm, and the average grain size (equivalent circle diameter) of Si particles contained in the first brazing filler metal layer and the second brazing filler metal layer is 1. Less than 8 μm,
After brazing with the aluminum alloy material constituting the cooler, the potential difference between the surface of the first brazing material layer and the core material is 50 mV or more, and the ratio t1 of the core material to the total thickness of the cladding material for the cooler The present invention relates to a cladding material for a heating element cooler excellent in formability, laser weldability, brazing property and corrosion resistance, characterized in that / T (%) satisfies the following formula.
t1 / T (%) ≧ 80% Expression T: Total thickness of the clad material for cooler, t1: Thickness of the core material.

The clad material for a cooler according to the present invention has a three-layer clad material comprising a core material, a sacrificial material layer covering one surface of the core material, and a brazing material layer covering the other surface of the core material. A clad material for a cooler , which is a graded O material, and constitutes a working fluid passage of a heat generating element cooler together with an aluminum alloy material, and the first brazing material layer side with respect to the aluminum alloy material. A clad material for a cooler brazed as the working fluid passage side,
The core material contains Mn, Cu, Si, Fe in the following content, or further contains one or more selected from Ti and Zr in the following content, with the balance being Al. Consists of aluminum alloy consisting of inevitable impurities,
Mn: 0.4 to 1.5 mass%, Cu: 0.05 to 0.8 mass%, Si: 0.05 to 1.0 mass%, Fe: 0.05 to 0.5 mass%, Ti: 0.05 to 0.20 mass%, Zr: 0.05 to 0.15 mass%,
The sacrificial material layer contains Zn in the following content, and contains one or more selected from Si, Fe, Mn, Ti, and Zr in the following content, with the balance being Al. It is comprised by the aluminum alloy brazing material which consists of an unavoidable impurity, Zn: 0.5-5.0 mass%, Si: 0.1-1.0 mass%, Fe: 0.1-0.2 mass%, Mn: 0.1 to 1.1% by mass, Ti: 0.05 to 0.20% by mass, Zr: 0.05 to 0.15% by mass The brazing filler metal layer contains Si and Fe in the following contents. And the balance is made of an aluminum alloy brazing material composed of Al and inevitable impurities, Si: 5.0 to 12.6% by mass, Fe: 0.1 to 0.7% by mass,
Before brazing with the aluminum alloy material constituting the cooler, the elongation is 15% or more, the average crystal grain size in the rolling direction of the rolling direction parallel section is 80 to 500 μm, and the average crystal grain size in the plate thickness direction 30 to 100 μm, the average particle diameter (equivalent circle diameter) of Si particles contained in the sacrificial material layer and the brazing material layer is less than 1.8 μm, and brazing with the aluminum alloy material constituting the cooler Later, the moldability is characterized in that the potential difference between the surface of the sacrificial material layer and the core material is 50 mV or more, and the ratio t1 / T (%) of the core material to the total thickness of the clad clad material satisfies the following formula. The present invention also relates to a cladding material for a heat generating element cooler that is excellent in laser weldability, brazing property and corrosion resistance.
t1 / T (%) ≧ 80% Expression T: Total thickness of the clad material for cooler, t1: Thickness of the core material.

The heat generating element cooler of the present invention is disposed so as to define a working fluid passage between the top plate obtained by press-molding the cooler cladding material described above and the top plate. A bottom plate made of an aluminum alloy material thicker than the top plate, and an inner fin housed between the top plate and the bottom plate, and the joined portions of these parts are brazed to each other The heat generating element configured and attached to the side of the top plate opposite to the working fluid passage is cooled by heat exchange with cooling water flowing in the working fluid passage.
The heat generating element cooler according to the present invention is characterized in that a cooling element substrate to which the heat generating element is bonded is brazed to a surface of the top plate opposite to the working fluid passage.

 The clad material for a cooler according to the present invention includes a core material, a first brazing material layer that covers one surface of the core material (a surface on the working fluid passage side), and a brazing material layer that covers the other surface. A clad material having a three-layer structure is rolled, and is structured as a graded O material that is finally annealed. The content of each component including Fe is defined within a specific range, and before and after brazing, elongation, average crystal Characteristic items such as particle size, average particle size of Si particles, potential difference, core material clad rate are specified within a predetermined range, so it has good press formability and can be accurately press formed into a top plate shape. it can.

 Further, in the clad material for a cooler of the present invention, the melting area by heat input can be kept small in the temporary fixing process by laser welding, and the processing amount by press molding is small in the temperature rising process in the brazing process. In addition, the core material can be recrystallized reliably in both the large amount of processing area and the amount of brazing material is prevented from eroding, and a sufficient amount of brazing material is supplied for brazing between joints. Is possible. Further, there is a potential gradient in the vicinity of the surface on the working fluid passage side, which exhibits corrosion resistance due to the sacrificial anode effect. Therefore, the progress of corrosion due to laser welds and brazing material erosion can be suppressed, and excellent corrosion resistance can be obtained as the top plate of the cooler.

 Further, according to the present invention, since the heat generating element cooler uses the above-described cooler clad material as a material for the top plate, the parts to be joined and the top plate and the cooling element substrate of each part constituting the cooler are used. In addition, it is possible to reliably braze and to suppress the progress of corrosion due to laser welded portion and brazing material erosion in the top plate, and to obtain excellent corrosion resistance. For this reason, even when the cooling water is flowed at a high speed, the generation of corrosion holes can be suppressed, and the cooling performance can be further improved.

It is a schematic longitudinal cross-sectional view which shows 1st Embodiment of the cooler for heat generating elements to which the cladding material for coolers of this invention is applied. FIG. 2 is a schematic longitudinal sectional view showing an example of a clad material for a cooler used as a top plate material in the heat generating element cooler shown in FIG. 1.

Hereinafter, specific embodiments of the present invention will be described.
<First and second embodiments>
First, 1st and 2nd embodiment of the cooler for heat generating elements to which the cladding material for coolers of this invention is applied is described.
FIG. 1 is a schematic longitudinal sectional view showing a first embodiment of a heat generating element cooler to which the clad material for a cooler according to the present invention is applied, and FIG. 2 is a top plate material in the heat generating element cooler shown in FIG. It is a schematic longitudinal cross-sectional view which shows an example of the clad material for coolers used as.

 A heat generating element cooler (hereinafter, simply referred to as “cooler”) 10 shown in FIG. 1 includes a bottom plate 1 having a shape in which a plurality of sections processed into a concave shape in cross section are connected in a surface direction, and a concave portion of the bottom plate 1. The accommodated inner fins 3 and the top plate 2 are laminated in this order, and by the brazing material layers 12 and 22 of the bottom plate 1 and the top plate 2, the joined portions 13 and 23 of the bottom plate 1 and the top plate 2, and Each surface 1a, 2a and the inner fin 3 are brazed and configured. Further, in the cooler 10 of this embodiment, a cooling element substrate 6 to which a heating element to be cooled is joined to the outer surface 2b (surface opposite to the cooling water passage 4) 2b of the top plate 2 is brazed. It is joined.

The bottom plate 1 and the top plate 2 function as structural members that define a cooling water passage (working fluid passage) 4 through which the cooling water 5 flows.
The bottom plate 1 has a plate shape, and a stepped portion (joined portion) 23 to be joined to the joined portion 13 of the top plate 2 is formed on the outer edge portion thereof. The bottom plate 1 is thicker than the top plate 2 described later, specifically, about 1.0 to 4.0 mm.
The top plate 2 is a plate body having substantially the same planar shape as the bottom plate 1, and a stepped portion (joined portion) 13 to be joined to the joined portion 23 of the bottom plate 1 is formed on the outer edge portion thereof. The top plate 2 is thinner than the bottom plate 1, and is specifically about 0.2 to 2.0 mm. And in this embodiment, the top plate 2 is comprised using the clad material 20 for coolers of this invention as a raw material. The configuration of the cooler clad material 20 will be described in detail later.
The bottom plate 1 and the top plate 2 are joined to each other by steps 13 and 23, and the cooling water sealed by the side walls of the step portions 13 and 23 is interposed between the bottom plate 1 and the top plate 2. A passage 4 is defined.

 The inner fin 3 functions as a heat transfer surface that contributes to heat exchange between the cooling water and the heating element. The inner fin 3 has a bellows shape and is accommodated in the cooling water passage 4. In the inner fin 3, each bent portion (joined portion) 33 is brazed to each surface (surface on the cooling water passage side) 1a, 2a of the bottom plate 1 or the top plate 2.

The cooling element substrate 6 has a surface (surface opposite to the top plate) 6a joined to a heating element 7 such as a semiconductor element via a solder layer 6b, while insulating the heating element 7 and the top plate 2 from each other. The heat generated by the heating element 7 is conducted to the top plate 2. As this cooling element substrate, for example, an insulating circuit substrate formed by bonding an aluminum layer 62 to both surfaces of a thermally conductive ceramic 61 such as AlN or Si ₃ N ₄ can be cited.
In the cooler 10 of this form, the heat generating element 7 is cooled via the inner fin 3, the top plate 2, and the cooling element substrate 6 by the cooling water flowing in the cooling water passage 4.

In order to manufacture the cooler 10 of this embodiment, first, a cooler clad material 20 described later is press-molded into a top plate shape to obtain a molded body (press-molding step). Next, after the cooling element substrate 6 is temporarily fixed to the molded body by laser welding, the molded body, the bottom plate 1 and the inner fin 3 are assembled, and the bonded portions 13, 23, 33 are temporarily bonded by laser welding. Stop (temporary fixing process). Then, for example, a fluoride-based flux (non-corrosive nocollock flux, Zn-substituted flux, etc.) is applied to the molded body, the bottom plate 1, the inner fin 3, and the cooling element substrate 6, and inert such as a high purity nitrogen gas atmosphere. Heat treatment is performed in an atmosphere furnace. The heat treatment temperature is about 590 to 620 ° C.
As a result, the brazing filler metal layer 22 included in the bottom plate 1 and the cooler clad material 20 melts and flows, and then the brazing filler metal is solidified by lowering the temperature in the furnace. As a result, the bonded portions 13 and 23, the bonded portion 33 of the inner fin 3, the inner surface of the top plate 2, the surface of the bottom plate 1, and the outer surface 2b of the top plate 2 and the cooling element substrate 6 are brazed. The cooler 10 is obtained (brazing step).

Next, the structure of the bottom plate 1, the top plate 2, and the inner fin 3 will be described in detail.
"Top board"
First, the structure of the top plate 2 will be described. The cooler 10 of the present invention is characterized in that the top plate 2 is made of the cooler clad material 20 of the present invention. That is, the top plate 2 is formed by molding the cooler clad material 20 into a top plate shape, and brazing the molded body to the other parts constituting the cooler 10, the bottom plate 1, the inner fins 3, and the cooling element substrate 6. It is configured.

 As shown in FIG. 2, the clad material 20 for a cooler includes a core material 21, a first brazing material layer 22 that covers one surface of the core material 21 (a surface on the cooling water passage 4 side), A clad material having a three-layer structure having a second brazing material layer 24 covering the other surface (the surface opposite to the cooling water passage 4), and the characteristic items described later are defined within a predetermined range, and will be described later. As it is, it is configured as a grade O material.

Hereinafter, the composition of each part 21, 22, 24 of the cooler clad material 20 will be described.
The core material 21 contains Mn, Cu, Si, Fe, or further contains one or more selected from Ti and Zr, and the balance is made of an aluminum alloy composed of Al and inevitable impurities. Yes. The content of each component is Mn: 0.4 to 1.5 mass%, Cu: 0.05 to 0.8 mass%, Si: 0.05 to 1.0 mass%, Fe: 0.05 to 0 0.5% by mass, Ti: 0.05 to 0.20% by mass, and Zr: 0.05 to 0.15% by mass. The action of each component is as follows.

Mn: Mn crystallizes or precipitates as an intermetallic compound, and has the effect | action which improves the intensity | strength of the top plate 2 after brazing. In addition, the formation of the Al—Mn—Si compound has the effect of lowering the Si solid solubility of the matrix and improving the melting point of the matrix.
If the Mn content is less than 0.4% by mass, these effects cannot be obtained sufficiently. Moreover, when content of Mn exceeds 1.5 mass%, the castability and workability (rollability) of a clad material will fall.

Si: Si is dispersed as an Al—Mn—Si compound or dissolved in a matrix, and has an effect of improving the strength of the core material 21.
When the Si content is less than 0.05% by mass, such an effect cannot be obtained sufficiently. Moreover, when content of Si exceeds 1.0 mass%, melting | fusing point of the core material 21 will fall, and the core material 21 may melt | dissolve at the time of brazing.

Cu: Cu is dissolved in the matrix and has an effect of improving the strength of the core material 21.
Further, Cu forms a concentration gradient from the core material 21 toward the brazing material on the passage side, and forms a potential gradient effective for corrosion prevention, thereby improving the pitting corrosion resistance of the clad material.
When the Cu content is less than 0.05% by mass, such an effect cannot be sufficiently obtained. On the other hand, if the Cu content exceeds 0.8% by mass, the melting point is lowered and the core material 21 may be melted during brazing.

Fe: Fe crystallizes or precipitates as an intermetallic compound, and has the effect of improving the strength of the top plate 2 after brazing. In addition, by forming Al-Mn-Fe-based, Al-Fe-Si-based, and Al-Mn-Fe-Si-based compounds, the solid solubility of Mn and Si in the matrix is reduced, and the melting point of the matrix is reduced. There is an effect to improve.
When the Fe content is less than 0.05% by mass, these effects cannot be obtained sufficiently. On the other hand, when the Fe content exceeds 0.5% by mass, the corrosion rate of the core material 21 is increased. Moreover, a giant crystallized substance appears, and this deteriorates the castability and rollability of the clad material.

Ti, Zr: Ti and Zr are dispersed as fine intermetallic compounds after brazing, and have the effect of improving the strength of the top plate 2.
If these contents are less than 0.05% by mass, such effects cannot be sufficiently obtained. Moreover, when Ti content exceeds 0.20 mass%, or when Zr content exceeds 0.15 mass%, the self-corrosion resistance and workability of a clad material will fall. Ti and Zn of less than 0.05% by mass are inevitable impurities.

The first brazing filler metal layer 22 is composed of the joined portion 13 of the cooler clad material 20 (top plate 2) and the joined portion 13 of the bottom plate 1, and the surface 2a of the cooler clad material 20 (top plate 2) and inner fins. A brazing material for brazing the three bent portions (joined portions) 33 is supplied.
The first brazing material layer 22 is made of an aluminum alloy brazing material containing Si, Zn, and Fe, and the balance of Al and inevitable impurities. The content of Si and Zn is Si: 4.5 to 11.0% by mass, Zn: 2.5 to 6.0% by mass, the content of Fe is 0.1 to 0.2% by mass, The action of each component is as follows.

Si: Si melts and flows by heat treatment in the brazing process, and then solidifies, thereby brazing the joined parts 13 and 23 and the surface 2a of the top plate 2 and the bent part 33 of the inner fin 3 with each other. Join. Moreover, Si has the effect | action which lowers melting | fusing point of a brazing material and improves the fluidity | liquidity in the molten state.
If the Si content is less than 4.5% by mass, the brazability becomes insufficient. When the Si content exceeds 11.0% by mass, Si greatly erodes the core material 21 or the joined members 1 and 3.
Zn: Zn diffuses into the core material 21 by the heat treatment in the brazing process, and forms a Zn concentration gradient in the depth direction from the surface 2a of the clad material 20 for the cooler (top plate 2). Since Zn has a relatively low potential, the formation of such a concentration gradient causes a potential gradient in the depth direction from the surface 2 a of the top 2.
In the top plate 2 on which such a potential gradient layer is formed, due to the sacrificial anode effect, the corrosion by the cooling water 5 preferentially proceeds in the surface direction, and the progress of the corrosion in the depth direction is suppressed. For this reason, generation | occurrence | production of a corrosion hole can be suppressed.
When the Zn content is less than 2.5% by mass, a sufficient potential gradient is not formed, and when the Zn content exceeds 6.0% by mass, the self-corrosion rate of the potential gradient layer becomes too high, Corrosion in the depth direction of the top plate 2 cannot be sufficiently suppressed.

 Fe: Fe diffuses into the core material at the time of final annealing, thereby promoting recrystallization in a low processing region during brazing and suppressing residual subcrystals in the cladding material. If the Fe content is less than 0.1% by mass, sub-crystals may remain. If it exceeds 0.2% by mass, the corrosion rate becomes too high, and the top plate 2 is sufficiently corroded in the depth direction. Can not be suppressed.

The second brazing material layer 24 supplies a brazing material that brazes the outer surface 2 b of the top plate 2 and the cooling element substrate 6.
The second brazing material layer 24 is composed of an aluminum alloy brazing material containing 5.0 to 12.6% by mass of Si and 0.1 to 0.7% by mass of Fe, with the balance being Al and inevitable impurities. ing,
Si: Si melts and flows by heat treatment in the brazing process, and then solidifies, thereby brazing the joined parts 13 and 23 and the surface 2a of the top plate 2 and the bent part 33 of the inner fin 3 with each other. Join. Moreover, Si has the effect | action which lowers melting | fusing point of a brazing material and improves the fluidity | liquidity in the molten state. Brazing property will become inadequate that content of Si is less than 5.0 mass%. On the other hand, when the Si content exceeds 12.6% by mass, coarse Si particles appear, rolling workability is lowered, and the core material 21 or the cooling element substrate 6 is greatly eroded.
Fe: Fe diffuses into the core material at the time of final annealing, thereby promoting recrystallization in a low-working region during brazing and suppressing residual subcrystals in the cladding material. If the Fe content is less than 0.1% by mass, sub-crystals may remain, and if it exceeds 0.7% by mass, the corrosion rate becomes too fast and the top plate 2 is sufficiently corroded in the depth direction. Can not be suppressed.

Next, the clad material and rolling process of the cooler clad material 20 will be described.
This cooler clad material 20 is a three-layer clad material having the above-described composition, with a rolling rate of cold rolling of one pass before final annealing performed at 20 to 45%, and the temperature increase rate of final annealing is increased. This is performed at 10 to 100 ° C./hour and corresponds to the grade O material obtained by cooling after holding at 300 to 450 ° C. for 1 to 6 hours as the final annealing condition.
By performing the rolling rate of one-pass cold rolling before the final annealing at 20 to 45%, the accumulated amount of strain near the brazing material / core material interface is increased and the recrystallized grain size near the interface is refined. Residual subcrystal grains can be suppressed in the low processing region. When cold rolling is performed at a rolling rate of less than 20%, strain is accumulated on the material surface (brazing material), so that the effect becomes insufficient. When cold rolling is performed at a rolling rate exceeding 45%, strain is accumulated inside the core material, so that the effect becomes insufficient.

By performing the temperature increase rate of the final annealing at 10 to 100 ° C./hour, the crystal grains before brazing can be refined, the formability can be improved, the recrystallization can be promoted in a low processing region, and the brazing erosion can be suppressed. When the heating rate is lower than 10 ° C./hour, the crystal grains before brazing become coarse, and when the heating rate exceeds 100 ° C./hour, the effect is saturated.
As a final annealing condition, by holding at 300 to 450 ° C. for 1 to 6 hours, the clad material is completely recrystallized, the elongation is improved, and the moldability is improved. Then, Fe added to the brazing material can be diffused into the core material at the core material interface.
Selecting a temperature of less than 300 ° C or maintaining the temperature for less than 1 hour tends to make the effect insufficient. Under annealing conditions exceeding 450 ° C for more than 6 hours, Si and Zn in the brazing material also diffuse. End up.

 Since the clad material 20 for a cooler is subjected to such a rolling process, when the brazing process is performed by press-molding the clad material 20, a region having a large amount of processing by press-molding and processing are performed in the temperature rising process. The core material can be reliably recrystallized in both of the regions with a small amount, and the formation of sub-crystal grains can be suppressed. Therefore, erosion of the molten brazing material entering the core material is suppressed, and the joined portions 13 and 23 are brazed between the surface 2 a and the bent portion 33 of the inner fin 3, and the outer surface 2 b and the cooling element substrate 6. A sufficient amount of brazing material can be supplied. Moreover, in the top plate 2, the progress of corrosion due to the wax erosion of the core material 21 is suppressed, and excellent pitting corrosion resistance can be obtained.

Next, the characteristic item which prescribes | regulates this clad material 20 for coolers is demonstrated.
In the clad material 20 for a cooler, as characteristics before brazing, the elongation, the average crystal grain size of the core material 21, and the average grain size (equivalent circle diameter) of Si particles contained in each brazing material layer 22 and 24 are defined. As the characteristics after brazing, the potential difference between the surface 2a of the first brazing material layer 22 and the core material 1 and the ratio of the core material 21 to the total thickness of the clad clad material are defined. Here, the characteristic of the clad member 20 for a cooler after brazing corresponds to the characteristic of the cooler 10 as the top plate 2.

[1] Characteristics before brazing Elongation before brazing and average crystal grain size of core material before brazing The elongation of the clad material 20 for cooler before brazing is specified to be 15% or more, and the average crystal grain size of the core material 21 is determined in the rolling direction. Preferably defines the average crystal grain size of the parallel cross section in the rolling direction to 80 to 500 μm, and the average crystal grain size of the core material 21 to 30 to 100 μm in the plate thickness direction.
By regulating the average crystal grain size to 80 to 500 μm in the rolling direction, press formability can be improved, recrystallization in a low working area during brazing is promoted, and residual subcrystals are suppressed. Can do.
By regulating the average crystal grain size to 30 to 100 μm in the plate thickness direction, press formability can be improved, recrystallization in a low working area during brazing is promoted, and subcrystals remain. be able to. Moreover, since the molten wax preferentially erodes the grain boundaries, it is possible to suppress the wax erosion in the depth direction.

When the average crystal grain size in the thickness direction of the core material 21 exceeds 100 μm, sufficient press formability cannot be obtained, and cracking occurs in the press forming process. At the same time, there arises a problem that recrystallization is delayed. In addition, the press formability of the clad material is improved as the average crystal grain size of the core material 21 is smaller. However, when the average crystal grain size is less than 30 μm, wax erosion in the depth direction is promoted. When the average grain size in the rolling direction of the core material 21 exceeds 500 μm, sufficient press formability cannot be obtained, and cracking occurs in the press forming process. At the same time, there arises a problem that recrystallization is delayed. When the average crystal grain size is less than 80 μm, the effect of improving press formability is saturated.
Since a clad material having an elongation of less than 15% has a small elongation, cracking is likely to occur when press molding, and it cannot be molded. The upper limit of elongation is not particularly specified, but is preferably 35% or less. The press formability of the clad material tends to improve as the elongation increases, but the effect becomes saturated when the elongation exceeds 35%.

As described above, the clad material 20 for a cooler is rolled. Here, when the rolling process is performed, the strength increases and the press formability may be impaired. However, even if the rolling process is performed, the elongation and the average crystal grain size of the core material 21 are within the above ranges. In this case, excellent press formability can be obtained, and the top plate can be accurately formed.
In the present invention, the average crystal grain size is obtained by polishing a cross section parallel to the rolling direction or a cross section along the plate thickness direction, and observing the crystal structure after electrolytic etching of these cross sections using a Barker's solution or the like. After carrying out the photography of this, it measured by the "straight line cutting method" described in JISG0551.

B. Average particle diameter of Si particles contained in each brazing material layer before brazing (equivalent circle diameter)
The average particle diameter (equivalent circle diameter) of the Si particles contained in the brazing filler metal layers 22 and 24 before brazing is defined to be less than 1.8 μm. Thereby, in the temporary fixing process by laser welding, the incidence of laser on the brazing filler metal layers 22 and 24 becomes slow, and control of the amount of heat input becomes easy, so that the welded portion can be kept small. As a result, in the top plate 2 of the obtained cooler 10, corrosion from the welded portion is less likely to occur, and generation of corrosion holes due to the progress of corrosion from the welded portion can be suppressed. Further, since the Si particles having an average particle size of less than 1.8 μm are fine, the melting progresses uniformly in each of the brazing filler metal layers 22 and 24 as a whole. As a result, the brazing property is improved, and particularly when the top plate 2 and the cooling element substrate 6 are brazed, brazing defects such as voids are hardly generated.
In the present invention, the average particle size of the Si particles is obtained by polishing a cross section parallel to the rolling direction, etching with 0.5% HF (hydrofluoric acid), observing the Si particles, and performing photography. The equivalent circle diameter was measured with an image analyzer. The magnification was 100 times, and the measurement was an average of 10 fields of view.

When the average particle size of Si particles contained in each brazing filler metal layer 22 and 24 exceeds 1.8 μm, the heat input to each brazing filler metal layer 22 and 24 proceeds rapidly during laser welding, and the melting area increases. Resulting in. As a result, in the top plate 2 of the obtained cooler 10, corrosion progresses from the welded portion to generate corrosion holes, and the clearance between the top plate 2 and the cooling element substrate 6 increases to reduce the heat exchange efficiency. However, there is a problem that the brazing material amount of each brazing material layer 22, 24 is insufficient and sufficient brazing performance cannot be obtained.
Although the minimum of the average particle diameter of Si particle | grains is not prescribed | regulated, it is preferable that it is 0.5 micrometer or more. The effect of alleviating laser incidence and the effect of improving brazing as described above tend to improve as the average particle size of the Si particles is finer, but the average particle size of the Si particles is less than 0.5 μm. Then the effect is saturated.

[2] Characteristics after brazing C.I. Potential difference between the surface of the first brazing material layer after brazing and the core material The potential difference between the surface 2a of the first brazing material layer 21 after brazing and the core material 21 is specified to be 50 mV or more.
When the clad material 20 for the cooler (top plate 2) has such a potential difference (potential gradient), a sacrificial anode effect is obtained in the vicinity of the surface 2a, and the progress of corrosion in the depth direction is suppressed. The For this reason, generation | occurrence | production of a corrosion hole can be suppressed.
When the potential difference is less than 50 mV, such a sacrificial anode effect cannot be obtained, and the effect of suppressing the progress of corrosion in the depth direction cannot be obtained. Further, the upper limit of the potential difference is not particularly defined, but is preferably 300 mV or less. The anticorrosion effect due to the potential gradient tends to improve as the potential difference increases. However, even if the potential difference exceeds 300 mV, no further effect can be obtained, and on the contrary, the corrosion rate becomes too high.
For the measurement of the potential difference, anodic polarization measurement is performed at 40 ° C., a 2.67% AlCl ₃ solution, and a potential sweep rate of 0.5 mV / s to measure the pitting potential. When measuring about a core material, after etching by 50 degreeC and 5% NaOH, the board center vicinity vicinity is measured.

D. Ratio of core material in total thickness after brazing The ratio t ₁ / T (%) of core material 21 in the total thickness after brazing is defined so as to satisfy the following formula.
t ₁ / T (%) ≧ 80% Expression T: Total thickness of the top plate, t ₁ : Thickness of the core material.
The ratio of the core material to the total thickness is measured by polishing the cross section parallel to the rolling direction, electrolytically etching with Barker's solution, specifying the interface between the core material and the brazing material. The interface is the average position in the field of view, and the measurement is the average of 10 fields.

  Since corrosion of the top plate 2 is likely to proceed due to the eutectic structure of the brazing material, if the ratio of the brazing material thickness to the core material thickness (core clad rate) is large, corrosion in the depth direction is likely to proceed. Corrosion holes occur early. On the other hand, if the ratio of the core material 21 occupying the total thickness satisfies a predetermined conditional expression, since the ratio of the brazing material thickness to the core material thickness is small, the progress of corrosion in the depth direction is suppressed, The generation of corrosion holes can be suppressed.

 The clad material 20 for a cooler configured as described above includes a core material 21, a first brazing material layer 22 that covers one surface of the core material 21 (the surface on the cooling water passage 4 side), The clad material having a three-layer structure having the second brazing material layer 24 covering the other surface (the surface opposite to the cooling water passage 4) is configured as described above, and is a graded O material. Since the characteristic items before and after brazing are defined within the predetermined range described above, good press formability can be obtained, and the top plate can be accurately press formed. Further, when a graded O material or the like is used, sub-crystal grains are particularly likely to be formed in a bent portion in order to form a step or a recess in the cooler clad material 20, and when rapid heating and cooling are performed in the annealing process, the crystal grains Therefore, the corrosion tends to proceed in the thickness direction of the clad material 20 for a cooler along the grain boundary of the sub-crystal grains. In this respect, it is a graded O material, which satisfies the above-mentioned various conditions. In particular, the first brazing filler metal layer 22 and the second brazing filler metal layer 24 contain appropriate amounts of Fe to appropriately promote recrystallization. Therefore, the cooler clad material 20 having a bent portion where sub-crystal grains are not present can be obtained.

 In addition, in the clad material 20 for a cooler, the melting area due to heat input can be kept small in the temporary fixing process by laser welding, and the processing amount by press molding is small in the temperature rising process in the brazing process. Since the core material 21 can be reliably recrystallized in both regions where the amount of processing is large, the erosion of the brazing material to the core material 21 is suppressed, and the bonded portions 13 and 23, the surface 2 a and the inner fin 3 It is possible to supply a sufficient amount of brazing material for brazing the bent portion 33, the outer surface 2 b and the cooling element substrate 6. Furthermore, it has a potential gradient in the vicinity of the surface 2a, and this exhibits corrosion resistance due to the sacrificial anode effect. Therefore, the progress of corrosion due to laser welding and brazing material erosion is suppressed, and excellent corrosion resistance is obtained as the top plate 2 of the cooler 10.

[Bottom plate]
As the bottom plate 1, any clad material or bare material usually used in this type of cooler 10 can be used. Specifically, the following can be mentioned.
As shown in FIG. 1, as the cladding material, a material having a core material 11 and a brazing material layer 12 covering one surface of the core material 11 (a surface on the cooling water passage 4 side) is used. be able to.

As a constituent material of the core material, an aluminum alloy such as an Al—Mn alloy or an Al—Mn—Cu alloy can be used. Specifically, examples include 3203 alloy and 3003 alloy according to JIS standards. In these aluminum alloys, the content of each component is preferably Mn: 1.0 to 1.5 mass% and Cu: 0.1 to 0.7 mass%.
Examples of the brazing material of the brazing material layer include aluminum alloy brazing materials such as an Al—Si—Zn alloy brazing material, and the content of each component is Si: 4 to 11 mass%, Zn: 0 to 5 mass%. Preferably there is.

Further, when the inner fin 3 has a brazing material layer, a clad material having a core material and a sacrificial material layer covering one surface of the core material (a surface on the cooling water passage 4 side), or A bare material having no cladding layer can also be used.
Here, as the core material of the clad material having the sacrificial material layer and the constituent material of the bare material, the same material as the core material of the clad material having the brazing material layer can be exemplified.
Examples of the sacrificial material for the sacrificial material layer include an aluminum alloy such as an Al—Zn alloy, and the Zn content is preferably 0 to 5% by mass. In addition, the Al—Zn alloy may contain Mn, Si, and Fe as necessary.

[Inner fin]
As the inner fin 3, any of the bare fin material and the clad fin material that are usually used in this type of cooler 10 can be used. Specifically, the following can be mentioned.
Examples of the bare fin material include those made of an aluminum alloy and those made of pure aluminum.

As an aluminum alloy, an Al—Mn alloy, an Al—Mn—Cu alloy, an Al—Mn—Zn alloy, an Al—Mn—Cu—Zn alloy, or the like can be used. 3003 alloy, 3203 alloy, etc. are mentioned. These aluminum alloys may contain Zn in a content of 0.5 to 2.0 mass%. Moreover, you may use an Al-Zn type alloy, and it is preferable that content of this Zn is 0.5-2.0 mass%.
Moreover, as pure aluminum, 1050, 1100, 1200 etc. are mentioned by JIS specification.

As the clad fin material, a material having a core material and a brazing material layer covering at least one surface of the core material can be used.
As the constituent material of the core material, the same aluminum alloy, pure aluminum or the like as the bare fin material can be used.
As a constituent material of the brazing material layer, the same aluminum alloy brazing material as the brazing material layer of the bottom plate 1 described above can be used.

 The cooler 10 configured as described above includes, as a configuration of the top plate 1, a core material 21 and a first wax that covers one surface of the core material 21 (a surface on the cooling water passage 4 side). A clad material having a three-layer structure having a material layer 22 and a second brazing material layer 24 covering the other surface (the surface opposite to the cooling water passage 4) is subjected to final annealing after rolling, and is classified into O By using the cooler clad material 20 that is configured as a material and whose characteristic items before and after brazing are defined within a predetermined range as described above, the bent portions 13 and 23, the surface 2a and the inner fin 3 are bent. The part 33, the outer surface 2b, and the cooling element substrate 6 are securely brazed and the top plate 2 can be prevented from being corroded by the laser welded part or the brazing material erosion, thereby obtaining excellent corrosion resistance. For this reason, even when the cooling water is flowed at a high speed, the generation of corrosion holes can be suppressed, and the cooling performance can be further improved.

<Third and Fourth Embodiment>
Next, third and fourth embodiments of a heat generating element cooler (heat generating element cooler of the present invention) to which another example of a clad material for a cooler according to the present invention is applied will be described. In the third and fourth embodiments, the description of the same configuration as in the first and second embodiments is omitted.
The heat generating element coolers of the third and fourth embodiments are configured in the same manner as in the first and second embodiments except that the structure of the cooler clad material 20 used as the material of the top plate 2 is different.

In this embodiment, the clad material for a cooler has a sacrificial material layer instead of the first brazing material layer 22, and other configurations, that is, a core material and a brazing material layer (the first material in the first embodiment). The composition of the brazing filler metal layer 24), the final rolling ratio, and the characteristic items before and after brazing are the same as those of the clad clad material 20 of the first embodiment. In this case, the inner fin is a clad material in which a core material and one surface (top plate side) or both surfaces of the core material are covered with a brazing material layer.
Hereinafter, the configuration of the sacrificial material layer will be described.

The sacrificial material layer forms a potential gradient layer on the cooling water passage side of the cooler clad material 20 (top plate 2) in the brazing process, and imparts corrosion resistance to the top plate 2 by the sacrificial anode effect.
The sacrificial material layer is provided so as to cover one surface of the core material 21 (the surface on the cooling water passage 4 side), contains Zn, and is selected from Si, Fe, Mn, Ti, and Zr. And the balance is made of an aluminum alloy composed of Al and inevitable impurities. The content of each component is Zn: 0.5 to 5.0 mass%, Si: 0.05 to 1.0 mass%, Fe: 0.05 to 0.2 mass%, Mn: 0.05 to 1 0.1% by mass, Ti: 0.05 to 0.20% by mass, and Zr: 0.05 to 0.15% by mass. The action of each component is as follows.

Zn: Zn forms a Zn concentration gradient in the depth direction from the surface 2a of the cooler clad material 20 (top plate 2) by heat treatment in the brazing process. Since Zn has a relatively low potential, the formation of such a concentration gradient causes a potential gradient in the depth direction from the surface 2 a of the top 2.
In the top plate 2 on which such a potential gradient layer is formed, the sacrificial anode effect causes corrosion by cooling water to preferentially proceed in the surface direction and suppress the progress of corrosion in the depth direction. For this reason, generation | occurrence | production of a corrosion hole can be suppressed.
When the Zn content is less than 0.5% by mass, a sufficient potential gradient is not formed, and when the Zn content exceeds 5.0% by mass, the self-corrosion rate of the potential gradient layer becomes too high, Corrosion in the depth direction of the top plate 2 cannot be sufficiently suppressed.

Si, Fe, Mn: These components crystallize or precipitate as an intermetallic compound, and have the effect of improving the strength, erosion resistance, and corrosion resistance of the top plate 2 after brazing.
When the content of each component is less than the lower limit, these effects cannot be obtained sufficiently. Moreover, if the content of each component exceeds the upper limit, the corrosion rate of the sacrificial material layer becomes too fast, and the corrosion of the core material cannot be sufficiently suppressed. For each element, the range of less than 0.05% by mass is the inevitable impurity range.

Ti, Zr: These components are dispersed as a fine intermetallic compound after brazing, and have the effect of improving the strength of the top plate 2.
If these contents are less than 0.05% by mass, such effects cannot be sufficiently obtained. Moreover, when Ti content exceeds 0.20 mass%, or when Zr content exceeds 0.15 mass%, the workability of a sacrificial material layer will fall. Ti and Zn of less than 0.05% by mass are inevitable impurities.

In the structure of the second embodiment, as in the case of the first embodiment, the potential difference between the surface of the sacrificial material layer after brazing and the core material 21 is defined to be 50 mV or more.
When the clad material 20 for the cooler (top plate 2) has such a potential difference (potential gradient), a sacrificial anode effect is obtained in the vicinity of the surface 2a, and the progress of corrosion in the depth direction is suppressed. The For this reason, generation | occurrence | production of a corrosion hole can be suppressed.
When the potential difference is less than 50 mV, such a sacrificial anode effect cannot be obtained, and the effect of suppressing the progress of corrosion in the depth direction cannot be obtained. Further, the upper limit of the potential difference is not particularly defined, but is preferably 300 mV or less. The anticorrosion effect due to the potential gradient tends to improve as the potential difference increases. However, even if the potential difference exceeds 300 mV, no further effect can be obtained, and on the contrary, the corrosion rate becomes too high.

 The clad material 20 for a cooler configured as described above includes a core material 21, a sacrificial material layer that covers one surface of the core material 21 (the surface on the cooling water passage 4 side), and the other surface ( A clad material having a three-layer structure having a brazing filler metal layer covering a surface opposite to the cooling water passage 4 is rolled at a final rolling rate of 10 to 25%, and characteristics before and after brazing Since the items are defined within the predetermined range described above, good press formability can be obtained, and the top plate can be accurately press formed.

 In addition, in the clad material 20 for a cooler, the melting area due to heat input can be kept small in the temporary fixing process by laser welding, and the processing amount by press molding is small in the temperature rising process in the brazing process. Since the core material can be surely recrystallized in both regions where the amount of processing is large, the erosion of the brazing material to the core material can be suppressed, and the outer surface 2b and the cooling element substrate 6 can be brazed. It is possible to supply a sufficient amount of brazing material. Furthermore, it has a potential gradient in the vicinity of the surface 2a, and this exhibits corrosion resistance due to the sacrificial anode effect. For this reason, the progress of corrosion due to the laser welded part and brazing material erosion is suppressed, and excellent corrosion resistance is obtained as the top plate 2 of the cooler 10.

Therefore, in the cooler using the clad material 20 for a cooler as described above as a material for the top plate 2, the top plate 2 and the cooling element substrate 6 are securely brazed and the top plate 2 has a laser welded portion or Progress of corrosion due to brazing metal erosion is suppressed, and excellent corrosion resistance is obtained. For this reason, even when the cooling water is flowed at a high speed, the generation of corrosion holes can be suppressed, and the cooling performance can be further improved.
As mentioned above, although embodiment of the heat exchanger of this invention was described, each part which comprises the said heat exchanger is an example, Comprising: It can change suitably in the range which does not deviate from the range of this invention.

Specific examples of the present invention will be described below, but the present invention is not limited to these examples.
A clad material having a cross-sectional shape shown in FIG. 1 formed by clad-bonding a brazing filler metal layer having a composition shown in Table 1 to a 3 mm thick aluminum alloy core material having a composition shown in Table 1 (mass%, the same applies hereinafter). A brazing material layer (passage-side brazing material) having a composition shown in Table 2 on one side of a bottom plate made of (thick clad material) and an aluminum alloy core material having a composition shown in Table 2 and having a thickness of 0.6 mm 1) clad material (thin plate clad) having a three-layer structure shown in FIG. 1 obtained by clad-bonding a brazing material layer (brazing material opposite to the passage) having a composition shown in Table 2 on the other surface. A top plate made of material was prepared. The top plate was press-molded into a cross-sectional structure shown in FIG. 1 having a size of 200 mm × 300 mm, a rectangular tube drawing shape, a depth of about 2 mm, and a flange portion of 10 mm. The bottom plate was press-molded into a cross-sectional structure shown in FIG. 1 having a size of 200 mm × 300 mm, a rectangular tube drawing shape, a depth of about 10 mm, and a flange portion of 10 mm. An inner fin having a shape of W: 60 mm × L: 170 mm and a fin height of 8 mm was used. Inner fins were prepared for each inner fin sample having the composition shown in Table 4 to be described later.

The bottom plate, top plate, and inner fin are assembled as shown in FIG. 1, and the temperature is increased at an average temperature increase rate of 25 ° C./min in a high purity nitrogen gas atmosphere (O ₂ concentration 20 ppm or less). The heat exchanger was manufactured by varying the amount of brazing by controlling the top plate temperature.
Moreover, it replaced with the thin-plate clad material of the structure shown in Table 2, and manufactured the heat exchanger similarly to the above using the thin-plate clad material which has an inner surface sacrificial material (passage side sacrificial material) shown in Table 3.
The obtained heat exchanger was subjected to a corrosion test. For the corrosion test, a corrosive solution adjusted to ion-exchanged water + (Cl ⁻ : 300 ppm, SO ₄ ²⁻ : 100 ppm, Cu ⁺⁺ : 100 ppm) NaCl, Na ₂ SO ₄ , CuCl ₂ was used. A test in which the flow rate (L / min) was changed for a test in which 60 L (liter) of the corrosive liquid was circulated inside the heat exchanger (80 ° C. × 8 h) and then room temperature × 16 h (circulation was stopped).

In the sample of Comparative Example 1 in which the Mn content of the thin clad material is outside the range of the present invention, the potential difference is not appropriate, and the top plate leaks, and the sample of Comparative Example 2 leaks at the joint. And the sample of the comparative example 3 which reduced Cu content became fin brazing defect. In the sample of Comparative Example 4 in which the Cu content of the core material was excessively large, leakage occurred on the top plate, and the sample of Comparative Example 5 in which the Zn content of the passage-side sacrificial material was small was found on the top plate due to poor brazing of the fins. A leak occurred. The sample of Comparative Example 6 in which the amount of Fe in the passage side brazing material and the opposite side brazing material was reduced leaked at the top plate, and the comparison was made in which the amount of Fe in the passage side brazing material and the opposite side brazing material was increased. In the sample of Example 7, leakage occurred on the top plate. The sample of Comparative Example 8 with a small amount of Zn in the passage-side sacrificial material leaks at the top plate due to insufficient potential difference, and Comparative Example 9 with too much Zn content leaks at the top plate or the joint due to preferential corrosion of the joint. Occurred.
Even in the case of the configuration of Example 5, as shown in Table 4, if the conditions of temperature rise rate, annealing temperature, and annealing time are outside the scope of the present invention as shown in Table 4, as shown in Table 5, insufficient corrosion resistance, laser Leakage occurred due to poor welding or press cracking.
With respect to these samples, the heat exchanger sample satisfying the conditions of the present invention did not cause a problem.

 DESCRIPTION OF SYMBOLS 1 ... Bottom plate, 2 ... Top plate, 2a ... Cooling water passage side surface, 2b ... Outer surface, 3 ... Inner fin, 6 ... Cooling element substrate, 7 ... Heat generating element, 11 ... Core material, 12 ... Brazing material layer, DESCRIPTION OF SYMBOLS 13 ... To-be-joined part, 21 ... Core material, 22 ... 1st brazing material layer, 23 ... To-be-joined part, 24 ... 2nd brazing material layer, 33 ... Bending part (to-be-joined part), 61 ... Heat conduction Ceramic, 62 ... aluminum layer.

Claims (6)

A core material, a three-layer structure having a first brazing material layer covering the one surface of the core material, and a second brazing material layer which covers the other surface of the core material, temper O A clad material for a cooler comprising a working fluid passage of an exothermic element cooler together with an aluminum alloy material, the first brazing material layer side being the working fluid passage side with respect to the aluminum alloy material A clad material for a cooler attached,
The core material includes Mn, Cu, Si, Fe in the following content, and the balance is made of an aluminum alloy composed of Al and inevitable impurities,
Mn: 0.4 to 1.5% by mass
Cu: 0.05-0.8 mass%
Si: 0.05-1.0 mass%
Fe: 0.05-0.5 mass%
The first brazing filler metal layer contains Si, Zn, and Fe in the following contents, and the balance is made of an aluminum alloy brazing filler metal composed of Al and inevitable impurities,
Si: 4.5-11.0 mass%
Zn: 2.5-5.0 mass%
Fe: 0.1 to 0.2% by mass
The second brazing filler metal layer contains Si and Fe in the following contents, and the balance is made of an aluminum alloy brazing filler metal composed of Al and inevitable impurities.
Si: 5.0-12.6 mass%
Fe: 0.1-0.7 mass%
Before brazing with the aluminum alloy material constituting the cooler, the elongation is 15% or more, the average crystal grain size in the rolling direction of the rolling direction parallel section is 80 to 500 μm, and the average crystal grain size in the plate thickness direction 30-100 μm, the average particle diameter (equivalent circle diameter) of Si particles contained in the first brazing filler metal layer and the second brazing filler metal layer is less than 1.8 μm,
After brazing with the aluminum alloy material constituting the cooler, the potential difference between the surface of the first brazing material layer and the core material is 50 mV or more, and the ratio t1 of the core material to the total thickness of the cladding material for the cooler A cladding material for a heating element cooler excellent in formability, laser weldability, brazing property and corrosion resistance, characterized in that / T (%) satisfies the following formula.
t1 / T (%) ≧ 80% Expression T: Total thickness of clad material for cooler t1: Thickness of core material A core material, a three-layer structure having a first brazing material layer covering the one surface of the core material, and a second brazing material layer which covers the other surface of the core material, temper O A clad material for a cooler comprising a working fluid passage of an exothermic element cooler together with an aluminum alloy material, the first brazing material layer side being the working fluid passage side with respect to the aluminum alloy material A clad material for a cooler attached,
The core material contains Mn, Cu, Si, Fe in the following content, and contains one or more selected from Ti and Zr in the following content, with the balance being inevitable with Al. Consists of aluminum alloy consisting of impurities,
Mn: 0.4 to 1.5% by mass
Cu: 0.05-0.8 mass%
Si: 0.05-1.0 mass%
Fe: 0.05-0.5 mass%
Ti: 0.05-0.20 mass%
Zr: 0.05 to 0.15% by mass
The first brazing filler metal layer contains Si, Zn, and Fe in the following contents, and the balance is made of an aluminum alloy brazing filler metal composed of Al and inevitable impurities,
Si: 4.5-11.0 mass%
Zn: 2.5-5.0 mass%
Fe: 0.1 to 0.2% by mass
The second brazing filler metal layer contains Si and Fe in the following contents, and the balance is made of an aluminum alloy brazing filler metal composed of Al and inevitable impurities.
Si: 5.0-12.6 mass%
Fe: 0.1-0.7 mass%
Before brazing with the aluminum alloy material constituting the cooler, the elongation is 15% or more, the average crystal grain size in the rolling direction of the rolling direction parallel section is 80 to 500 μm, and the average crystal grain size in the plate thickness direction 30-100 μm, the average particle diameter (equivalent circle diameter) of Si particles contained in the first brazing filler metal layer and the second brazing filler metal layer is less than 1.8 μm,
After brazing with the aluminum alloy material constituting the cooler, the potential difference between the surface of the first brazing material layer and the core material is 50 mV or more, and the ratio t1 of the core material to the total thickness of the cladding material for the cooler A cladding material for a heating element cooler excellent in formability, laser weldability, brazing property and corrosion resistance, characterized in that / T (%) satisfies the following formula.
t1 / T (%) ≧ 80% Expression T: Total thickness of clad material for cooler t1: Thickness of core material A core material, and the sacrificial material layer covering the one surface of the core material, a three-layer structure having a brazing material layer which covers the other surface of the core material, a temper O material, heating A clad material for a cooler comprising a working fluid passage of an element cooler together with an aluminum alloy material, the clad material for a cooler being brazed to the aluminum alloy material with the sacrificial material layer side as a working fluid passage side. And
The core material includes Mn, Cu, Si, Fe in the following content, and the balance is made of an aluminum alloy composed of Al and inevitable impurities,
Mn: 0.4 to 1.5% by mass
Cu: 0.05-0.8 mass%
Si: 0.05-1.0 mass%
Fe: 0.05-0.5 mass%
The sacrificial material layer contains Zn in the following content, and contains one or more selected from Si, Fe, Mn, Ti, and Zr in the following content, with the balance being Al. It is composed of an aluminum alloy brazing material consisting of inevitable impurities,
Zn: 0.5-5.0 mass%
Si: 0.05-1.0 mass%
Fe: 0.05 to 0.2% by mass
Mn: 0.05 to 1.1% by mass
Ti: 0.05-0.20 mass%
Zr: 0.05 to 0.15% by mass
The brazing filler metal layer contains Si and Fe in the following content, and the balance is composed of an aluminum alloy brazing filler metal composed of Al and inevitable impurities,
Si: 5.0-12.6 mass%
Fe: 0.1-0.7 mass%
Before brazing with the aluminum alloy material constituting the cooler, the elongation is 15% or more, the average crystal grain size in the rolling direction of the rolling direction parallel section is 80 to 500 μm, and the average crystal grain size in the plate thickness direction 30 to 100 μm, the average particle diameter (equivalent circle diameter) of Si particles contained in the sacrificial material layer and the brazing material layer is less than 1.8 μm,
After brazing with the aluminum alloy material constituting the cooler, the potential difference between the surface of the sacrificial material layer and the core material is 50 mV or more, and the ratio t1 / T of the core material to the total thickness of the cladding material for the cooler ( %) Satisfying the following formula: a clad material for a heating element cooler excellent in formability, laser weldability, brazing property and corrosion resistance.
t1 / T (%) ≧ 80% Formula T: Total thickness of cooler clad material t1: Thickness of core material A core material, and the sacrificial material layer covering the one surface of the core material, a three-layer structure having a brazing material layer which covers the other surface of the core material, a temper O material, heating A clad material for a cooler comprising a working fluid passage of an element cooler together with an aluminum alloy material, the clad material for a cooler being brazed to the aluminum alloy material with the sacrificial material layer side as a working fluid passage side. And
The core material contains Mn, Cu, Si, and Fe in the following contents, and contains at least one selected from Ti and Zr in the following contents, with the balance being made of Al and inevitable impurities. Composed of aluminum alloy,
Mn: 0.4 to 1.5% by mass
Cu: 0.05-0.8 mass%
Si: 0.05-1.0 mass%
Fe: 0.05-0.5 mass%
Ti: 0.05-0.20 mass%
Zr: 0.05 to 0.15% by mass
The sacrificial material layer contains Zn in the following content, and contains one or more selected from Si, Fe, Mn, Ti, and Zr in the following content, with the balance being Al. It is composed of an aluminum alloy brazing material consisting of inevitable impurities,
Zn: 0.5-5.0 mass%
Si: 0.05-1.0 mass%
Fe: 0.05 to 0.2% by mass
Mn: 0.05 to 1.1% by mass
Ti: 0.05-0.20 mass%
Zr: 0.05 to 0.15% by mass
The brazing filler metal layer contains Si and Fe in the following content, and the balance is composed of an aluminum alloy brazing filler metal composed of Al and inevitable impurities,
Si: 5.0-12.6 mass%
Fe: 0.1-0.7 mass%
Before brazing with the aluminum alloy material constituting the cooler, the elongation is 15% or more, the average crystal grain size in the rolling direction of the rolling direction parallel section is 80 to 500 μm, and the average crystal grain size in the plate thickness direction 30 to 100 μm, the average particle diameter (equivalent circle diameter) of Si particles contained in the sacrificial material layer and the brazing material layer is less than 1.8 μm,
After brazing with the aluminum alloy material constituting the cooler, the potential difference between the surface of the sacrificial material layer and the core material is 50 mV or more, and the ratio t1 / T of the core material to the total thickness of the cladding material for the cooler ( %) Satisfying the following formula: a cladding material for a heating element cooler excellent in formability, laser weldability, brazing property and corrosion resistance.
t1 / T (%) ≧ 80% Formula T: Total thickness of cooler clad material t1: Thickness of core material A working fluid passage is defined between the top plate obtained by press-molding the cooler clad material according to any one of claims 1 to 4 and the top plate. A bottom plate made of an aluminum alloy material that is thicker than the plate, and an inner fin housed between the top plate and the bottom plate. A heat generating element cooler, wherein a heat generating element attached to the top plate opposite to the working fluid passage is cooled by heat exchange with cooling water flowing in the working fluid passage. 6. The cooler for a heating element according to claim 5 , wherein a cooling element substrate to which the heating element is joined is brazed to a surface of the top plate opposite to the working fluid passage side.

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