KR20140128106A - A high strength clad sheet having erosion resistance and Manufacturing method of the same - Google Patents

Abstract

According to the present invention, a high strength clad sheet with erosion resistance for brazing includes a core member and a skin member. The core member is thinly casted to include 0.4-0.7 wt% of silicon (Si), 0.34-0.6 wt% of ion (Fe), 0.6-1.0 wt% or less of copper (Cu), 0.9-1.5 wt% of manganese (Mn), 0.05-0.15 wt% of chrome (Cr), 0.1 wt% or less of magnesium (Mg) and titanium (Ti), the remainder consisting of aluminum (Al) and inevitable impurities, then is uniformized and cold-rolled. The skin member is formed by thinly casting an aluminum alloy including 6.8-8.2 wt% of silicon (Si), then the aluminum alloy is uniformized and cold-rolled. The skin member roll-bonded with the core member is cold-rolled and annealed.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a high strength clad sheet for brazing,

The present invention relates to a high-strength clad plate for brazing having corrosion resistance and a method of manufacturing the same, and more particularly, to a method of manufacturing a high-strength clad plate for brazing, which comprises using a thin plate-cast aluminum alloy as a core material and a workpiece, performing a homogenization heat treatment and a roll bonding and an annealing process Strength clad plate for brazing, and a method of manufacturing the same.

The present invention relates to a high-strength clad plate for brazing, which has corrosion resistance and is capable of enhancing strength by inducing crystal grain refinement by selectively adding zirconium (Zr) to form an Al ₃ Zr phase, and a method for manufacturing the same.

Since the aluminum alloy is lightweight and has high thermal conductivity, it is used in an automobile heat exchanger such as a radiator, a condenser, an evaporator, a heater, an intercooler, and the like. Automobile heat exchangers are mainly manufactured by the brazing method.

On the other hand, in the case of a heat exchanger for an indoor / outdoor use of an air conditioner manufactured by intubation after stacking aluminum pins, a manufacturing process by a brazing method has been attempted in recent years as a demand for weight reduction and miniaturization.

Typically, brazing takes place at a high temperature of about 600 DEG C using brazing filler metal of an Al-Si based alloy. Therefore, an aluminum alloy brazing sheet having excellent brazing property and high strength and corrosion resistance after brazing is required.

The aluminum alloy heat exchanger manufactured by brazing is mainly composed of a corrugated fin which is responsible for heat dissipation and a tube for circulating cooling water or refrigerant. If the tube penetrates by corrosion or fracture, leakage of cooling water or refrigerant circulating inside the tube occurs. Therefore, in order to improve the life of the product, an aluminum alloy brazing sheet excellent in strength after brazing and corrosion resistance is indispensable.

[0003] In recent years, there has been a growing demand for lightweight automobiles, and a lightweight automotive heat exchanger is also required to cope with this. Therefore, it has been studied to make each member constituting the heat exchanger thinner, and it is necessary to further improve the strength after brazing of the aluminum alloy brazing sheet.

This is also required in the case of an aluminum brazing sheet which is applied to a heat exchanger for indoor / outdoor use of an air conditioner.

Conventionally, as a tube material of a heat exchanger in which cooling water circulates on the inner surface of a tube, such as radiators and heaters for automobiles, an Al-Zn (Al-Zn) alloy is used on the inner surface side of a core material such as an Al- A three-layered tube material in which a sacrificial anode material such as a base alloy is clad and a brazing filler metal such as an Al-Si alloy is clad at the air side has been generally used.

However, the strength of the clad material using JIS 3003 alloy core material is about 110 MPa after brazing, and the strength is insufficient.

In order to improve the strength after brazing, a three-layered clad tube material in which Mg is added to a core material has been proposed (see Japanese Patent Application Laid-Open Nos. 8-246117 and 2003-55727).

However, when Mg is added to the core material, the fluoride-based flux used in the Nocolock Brazing reacts with Mg to form a compound such as MgF 2, thereby remarkably lowering the brazing property.

Korean Patent Publication No. 2007-0061413 discloses a process for producing an aluminum alloy brazing sheet produced by casting an aluminum alloy for a core material, an intermediate material and a sacrificial anode material to prepare a core material, an intermediate material and a sacrificial cathode material, homogenizing the material, Method "is disclosed.

However, in the case of an alloy containing a large amount of alloying elements, there is a problem that the unevenness of the casting structure is increased and the occurrence of defects is increased in the rolling joining and the subsequent rolling of the thin plate.

In addition, since it is manufactured through a lot of rolling processes, the productivity is lowered and a large amount of energy is required.

In addition, when the tube material and the fin material are brazed during the heat exchanger manufacturing process, if the tube material is excessively eroded, it causes leakage of the refrigerant. Therefore, it is impossible to use the heat exchanger itself and improvement of the corrosion resistance of the tube material is required .

On the other hand, Fig. 1 is a table showing the composition of JIS3003 aluminum alloy as a core material for a heat exchanger tube material which is generally used, and has a high tensile strength and yield strength but a low elongation of 4.0% or less. % Erosion ratio.

An object of the present invention is to solve the problems of the prior art. More specifically, the present invention relates to a method of manufacturing a brazing material for use in brazing, which comprises the steps of using an aluminum alloy cast as a core material and a workpiece and performing roll bonding and annealing steps after homogenizing heat treatment, Strength clad plate material and a method of manufacturing the same.

Another object of the present invention is to provide a high-strength clad sheet for brazing having a corrosion resistance capable of enhancing strength by inducing grain refinement by selectively adding zirconium (Zr) to form an Al ₃ Zr phase, and a method for manufacturing the same .

The high-strength clad sheet for brazing according to the present invention is characterized by comprising 0.4 to 0.7 wt% of silicon (Si), 0.34 to 0.6 wt% of iron (Fe), 0.6 to 1.0 wt% of copper ), Manganese (Mn) in an amount of 0.9 to 1.5 wt%, chromium (Cr) in an amount of 0.05 to 0.15 wt%, magnesium (Mg) and titanium (Ti) in an amount of 0.1 wt% or less, aluminum Al and other unavoidable impurities, and an aluminum alloy containing 6.8 to 8.2% by weight of silicon (Si) are homogenized and cold rolled, and the core and the roll And an object to be bonded and annealed in the state of being attached and cold-rolled.

And the core material further comprises 0.1 to 0.3% by weight of zirconium (Zr).

And the clad sheet material has an erosion ratio of 8.8% or less.

And the core material has an elongation of 7.5% or more.

And the object is JIS4343.

A method of manufacturing a high-strength clad sheet for brazing having corrosion resistance according to the present invention is characterized by comprising the steps of: 0.4 to 0.7 wt% of silicon (Si); 0.34 to 0.6 wt% of iron (Fe); 0.6 to 1.0 wt% (Mn), 0.05 to 0.15 wt% of chromium (Cr), 0.1 wt% or less of magnesium (Mg) and titanium (Ti), and the balance of A material preparation step of preparing a thin plate-casted core material containing aluminum (Al) and other unavoidable impurities and an aluminum alloy containing 6.8 to 8.2% by weight of silicon (Si) by thin-plate casting; A surface treatment step of wire-brushing the surface to be joined of the core material and the image material; a bonding step of laminating and bonding the core material and the image material by roll bonding; A rolling step of cold-rolling the core material and the substrate, It characterized by annealing the rolled core with victims of an accident comprising the annealing step for producing a high-strength clad plate.

The core material may further contain zirconium (Zr) in an amount of 0.1 to 0.3 wt%.

In the material pre-treatment step, the core material and the substrate are homogenized for 1 to 2 hours in a temperature range of 400 to 450 ° C.

Wherein the annealing step is performed at a temperature ranging from 320 to 440 ° C.

As described in detail above, the high-strength clad plate for brazing having corrosion resistance according to the present invention and the method of manufacturing the same are manufactured by using a thin-plate-cast aluminum alloy as a core material and an object, performing a homogenization heat treatment, a roll bonding and an annealing process .

Therefore, there is an advantage that the erosion resistance is improved and the damage of the heat exchanger can be minimized.

Further, in the present invention, crystal grain refinement can be induced by selectively adding zirconium (Zr) to form an Al ₃ Zr phase.

Therefore, the strength can be improved, the thickness is thin, the composition deviation is not so great, and the occurrence of defects is minimized.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a table showing the composition of a core material for a heat exchanger tube material generally used; Fig.
2 is a table showing the composition of a high strength clad plate for brazing having corrosion resistance according to the present invention.
3 is a photograph showing the appearance of a high-strength clad plate for brazing having erosion resistance according to the present invention.
4 is a flow chart showing a method of manufacturing a high-strength clad plate for brazing having corrosion resistance according to the present invention.
5 is a schematic view showing a method of manufacturing a high-strength clad plate for brazing having corrosion resistance according to the present invention.
6 is a photograph showing a state in which a bonding step is completed in a method of manufacturing a high strength clad sheet for brazing having corrosion resistance according to the present invention.
FIG. 7 is a table showing changes in hardness according to a change in the reduction rate during the rolling step in the method for manufacturing a high-strength clad plate for brazing having erosion resistance according to the present invention.
FIGS. 8 and 9 are graphs showing changes in strength with temperature change during the annealing step for the first and second preferred embodiments of the present invention. FIG.
10 is a table comparing tensile strength, yield strength and elongation before and after brazing with respect to preferred embodiments of the present invention and comparative materials.
11 and 12 are test results and actual photographs for confirming the formability of a high strength clad plate for brazing having corrosion resistance according to the present invention.
FIGS. 13 and 14 are photographs and table showing the results of the corrosion resistance test of the high-strength clad plate for brazing having corrosion resistance according to the present invention.
Figs. 15 and 16 are TEM photographs and EDS analysis results for confirming precipitation phase due to addition of zirconium (Zr) in a high-strength clad plate for brazing with erosion resistance according to the present invention.

The composition of the high-strength clad plate for brazing (hereinafter referred to as 'clad plate 100') having corrosion resistance according to the present invention will be described with reference to FIGS. 2 and 3 attached hereto.

FIG. 2 is a table showing the composition of a high-strength clad plate for brazing with corrosion resistance according to the present invention, and FIG. 3 is a photograph showing the external appearance of the high-strength clad plate for brazing with corrosion resistance according to the present invention have.

Prior to the description, terms and words used in the present specification and claims should not be construed in a conventional and dictionary sense, and the inventor should appropriately define the concept of the term in order to describe its invention in the best way The present invention should be construed in accordance with the meaning and concept consistent with the technical idea of the present invention.

Therefore, the embodiments described in the present specification and the configurations shown in the drawings are merely preferred embodiments of the present invention, and are not intended to represent all of the technical ideas of the present invention. Therefore, various equivalents It should be understood that water and variations may be present.

The clad plate 100 according to the present invention comprises a core material and a substrate, and both the core material and the substrate are manufactured through a thin plate casting process.

Further, the core material and the substrate have different compositions from each other.

More specifically, the core comprises 0.4 to 0.7 wt% of silicon (Si), 0.34 to 0.6 wt% of iron (Fe), 0.6 to 1.0 wt% of copper (Cu), 0.9 to 1.5 wt% (Mn), 0.05 to 0.15 wt% of chromium (Cr), 0.1 wt% or less of magnesium (Mg) and titanium (Ti), the balance aluminum (Al) and other unavoidable impurities So that it is laminated.

The substrate is formed by thin-plate casting an aluminum alloy containing 6.8 to 8.2% by weight of silicon (Si).

The core material and the substrate having the above composition are homogenized, rolled and adhered to each other, and are finished with the clad plate 100 having high strength and erosion resistance through cold rolling and annealing.

At this time, the clad plate 100 has an erosion ratio of 8.8% or less and an elongation of 7.5% or more.

The core material may further contain 0.1 to 0.3% by weight of zirconium (Zr). That is, the core of Example 1 of the present invention contains zirconium, and the core of Example 2 does not contain zirconium.

Whether or not zirconium is added to the core material can be determined in consideration of strength and erosion ratio among the physical properties required for the clad sheet 100. When zirconium is added, Al3Zr can be formed to maximize strength improvement.

On the other hand, JIS 4334 was adopted as the above-mentioned material.

A method of manufacturing the clad plate 100 will be described with reference to FIGS. 4 and 5 attached hereto.

FIG. 4 is a flow chart showing a manufacturing process of a high-strength clad plate 100 for brazing having corrosion resistance according to the present invention. FIG. 5 shows a process flow chart of a high-strength clad plate 100 for brazing, Is a schematic view showing a manufacturing method of the first embodiment.

As shown in the drawing, the method for fabricating the clad plate 100 includes a step of preparing a core material having a composition as described above and a thin film-cast core material and a substrate, a step (S100) of preparing a core material and a workpiece homogenized and homogenized (S300) for wire-brushing a surface to be joined of the core material and the object, a bonding step (S400) for laminating and bonding the core material and the substrate, and a roll bonding (S500) for cold-rolling the core material and the substrate, and an annealing step (S600) for annealing the rolled core material and the substrate to manufacture the high-strength clad sheet material (100).

(TCR3527M) in which zirconium (Zr) was added and a material (TCR3527) in Example 2 in which zirconium (Zr) was not added were prepared as the core material in the material preparation step (S100), and the material was JIS4343 Prepared.

Both the core and the substrate were manufactured through a thin plate casting process, and all were continuously manufactured to have a thickness of 4 mm.

After the material preparing step S100, a material pre-processing step S200 is performed. The material pretreatment step (S200) is completed by homogenizing both the core material and the substrate, and further performing the cold rolling process only after the homogenization treatment.

In the embodiment of the present invention, the homogenization treatment was carried out in a temperature range of 400 to 450 ° C. for 1 hour, and the workpiece was reduced to a thickness of 4 mm to 0.4 mm through cold rolling.

After the material preprocessing step (S200), a surface processing step (S300) is performed. The surface treatment step (S300) is a process of improving the bonding force between the coating material and the core material during the bonding step (S400), and is a process of surface-treating the surface to be bonded of the core material and the coating material through a wire brushing process.

After the surface treatment step (S300), a bonding step (S400) is performed. In the joining step (S400), core material is positioned at the center and cladding is performed by disposing a material on the upper and lower sides.

Upon completion of the joining step (S400), the clad plate 100 of the embodiment of the present invention has a thickness of 2.0 to 2.6 mm.

After the joining step (S400), a rolling step (S500) is performed. The rolling step S500 is a process of cold-rolling the clad sheet 100 to have a thickness of 0.22 mm.

When the rolling step (S500) is completed, the continuous clad plate material 100 becomes thinner in the state as shown in FIG.

As shown in FIG. 7, the clad plate 100 has a hardness of 120 Hv or more when the final thickness is 0.22 mm through the joining step (S400) and the rolling step (S500).

FIG. 7 is a chart showing the change in hardness with the change in the reduction rate during the rolling step in the manufacturing method of the high-strength clad plate 100 for brazing with erosion resistance according to the present invention.

After the rolling step (S500), an annealing step (S600) is performed. The annealing step (S600) is a process of heating the clad sheet material (100) to a temperature just before the recrystallization occurs. The annealing step (S600) is preferably performed within a temperature range of 320 to 440 ° C Do.

FIGS. 8 and 9 are graphs showing changes in strength according to temperature changes during the annealing step for the first and second preferred embodiments of the present invention. It was found that the clad plate material 100 in which the core material of Example 1 was adopted had recrystallization and hardness reduction at 420 DEG C and was the annealing treatment temperature.

The clad sheet 100 including the core material of Example 2 containing no zirconium was found to have a recrystallization temperature and a hardness reduced at 400 ° C, indicating the annealing treatment temperature.

As a result of comparing the properties before and after brazing with respect to the clad plate 100 manufactured through the above steps, the tensile strength and the yield strength before and after brazing were superior to those of the comparative material, and the elongation was also higher than that of the comparative material Respectively.

However, the characteristics were different depending on whether zirconium (Zr) was added or not. That is, in the case of the clad plate 100 including the core material of Example 1 in which zirconium (Zr) was added, both the tensile strength and the yield strength were higher than those of the core material of Example 2 in which zirconium (Zr) Respectively.

However, the clad sheet material 100 including the core material containing no zirconium (Zr) had a relatively good elongation at the pre-brazing step.

Therefore, the first and second embodiments can be selectively included according to the characteristics required for the clad plate 100.

The moldability of the clad sheet 100 will now be described with reference to FIGS. 11 and 12. FIG.

11 and 12 are test results and actual photographs for confirming the formability of the high-strength clad plate 100 for brazing having corrosion resistance according to the present invention.

As shown in the figure, the clad plates 100 produced by heat-treating the core materials of Examples 1 and 2 for 14 hours within the temperature range of 380 to 420 占 폚 exhibited a minimum radius of curvature of 0.1 mm or less, And the shearing of the substrate and the shear of the clad plate 100 did not occur, so that the moldability was judged to be good.

13 and 14 are photographs and tables showing the results of the corrosion resistance test of the high-strength clad plate 100 for brazing with erosion resistance according to the present invention, wherein the erosion depth ratio of Examples 1 and 2 is lower than that of the comparative material Respectively.

However, it was confirmed that when the core material of Example 2 in which zirconium was not added was subjected to the annealing step (S600) at 380 ° C, the erosion resistance was lowered.

Therefore, it is more preferable to perform the annealing step (S600) at 400 deg. C for the core material of the second embodiment in consideration of the erosion resistance.

15 and 16 are TEM photographs and EDS analysis results for confirming precipitation phases due to addition of zirconium (Zr) in a high-strength clad plate 100 for brazing with erosion resistance according to the present invention.

When zirconium (Zr) was added as shown in the figure, it was confirmed that a precipitate phase such as Al ₃ Zr was formed as shown in the photograph on the upper side of FIG. 15 and FIG. 16, and the tensile strength and the yield strength were improved by this precipitation phase.

As shown in FIG. 15, a common precipitation phase such as Al ₆ Mn, Al ₆ Fe, α-AlMnSi, and α-AlFeSi was found regardless of addition of zirconium (Zr).

The scope of the present invention is not limited to the above-described embodiments, and many other modifications based on the present invention will be possible to those skilled in the art within the scope of the present invention.

100. Clad plate material S100. Steps to prepare the material
S200. Material preprocessing step S300. Surface treatment step
S400. Bonding step S500. Rolling step
S600. Annealing step

Claims (9)

(Si), 0.34 to 0.6 wt% of iron (Fe), 0.6 to 1.0 wt% of copper (Cu), 0.9 to 1.5 wt% of manganese (Mn), 0.05 to 0.7 wt% of silicon To 0.15% by weight of chromium (Cr), 0.1% by weight or less of magnesium (Mg) and titanium (Ti), the balance aluminum (Al) and other unavoidable impurities, The core,
Characterized by comprising an aluminum alloy containing 6.8 to 8.2% by weight of silicon (Si), homogenized and cold-rolled, cold-rolled and annealed in a state of being rolled and adhered to the core material A high-strength clad plate for brazing.
The high strength clad plate for brazing according to claim 1, wherein the core further comprises 0.1 to 0.3% by weight of zirconium (Zr).
The high strength clad plate for brazing according to claim 2, wherein the clad sheet material has an erosion ratio of 8.8% or less.
The high strength clad plate for brazing according to claim 3, wherein the core has an elongation of 7.5% or more.
5. The high-strength clad plate for brazing according to claim 4, wherein the workpiece is JIS 4334. 6. The high-strength clad plate for brazing according to claim 4,
(Si), 0.34 to 0.6 wt% of iron (Fe), 0.6 to 1.0 wt% of copper (Cu), 0.9 to 1.5 wt% of manganese (Mn), 0.05 to 0.7 wt% of silicon (Al) and other unavoidable impurities, and at least one of the following materials: 6.8 (a), (b) and (c) To 8.2% by weight of silicon (Si);
A material pretreatment step of subjecting the core material and the substrate to a homogenization treatment and cold-rolling the homogenized substrate,
A surface treatment step of wire-brushing the surface to be joined of the core material and the object,
A joining step of laminating the core material and the substrate and roll bonding,
A rolling step of cold-rolling the roll-bonded core and the substrate,
And an annealing step of annealing the rolled core material and the workpiece to produce a high-strength clad sheet material.
[7] The method of claim 6, wherein the core material further comprises 0.1 to 0.3% by weight of zirconium (Zr) in the material preparation step.
8. The method of claim 7, wherein the core material and the substrate are homogenized in a temperature range of 400 to 450 DEG C for 1 to 2 hours in the material pretreatment step.
The method of claim 8, wherein the annealing step is performed at a temperature ranging from 320 to 440 캜.

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