WO2023068166A1

WO2023068166A1 - Method for producing extruded multi-hole pipe

Info

Publication number: WO2023068166A1
Application number: PCT/JP2022/038245
Authority: WO
Inventors: 太一鈴木; 稜東森
Original assignee: 株式会社Uacj
Priority date: 2021-10-20
Filing date: 2022-10-13
Publication date: 2023-04-27
Also published as: CN117957340A; JP2023061741A

Abstract

In this method for producing an extruded multi-hole pipe (1), an ingot is produced, which has a chemical composition containing one or more elements from among Si: 2.0 mass% or less, Fe: 0.6 mass% or less, Cu: 0.6 mass% or less, Mn: 2.0 mass% or less, Mg: 0.4 mass% or less, Cr: 0.1 mass% or less, Zn: 1.5 mass% or less, Ti: 0.1 mass% or less and B: 0.1 mass% or less, with the remainder comprising Al and unavoidable impurities, the total content of Si and Mn being 3.2 mass% or less, the Si content being less than the Mn content. After a first homogenisation treatment in which the ingot is kept at a temperature of 550-650°C for 2 or more hours, a second homogenisation treatment is performed in which the ingot is kept at a temperature of 450-540°C for 3 or more hours. The ingot is then hot-extruded.

Description

Method for manufacturing extruded multi-hole pipe

The present invention relates to a method for manufacturing an extruded multi-hole pipe.

The extruded multi-hole pipe has an outer wall portion that constitutes its outer peripheral portion and a partition wall portion that defines a space surrounded by the outer wall portion, and the fluid flows through the passage surrounded by the outer wall portion and the partition wall portion. It is configured so that it can be In order to form a complex cross-sectional shape with such a fine structure by extrusion, the extruded multi-hole tube is made of an aluminum alloy with a relatively low content of alloying elements and excellent extrudability. There are many things.

For example, in Patent Document 1, in terms of mass%, Si: 0.01 to 0.3%, Fe: 0.01 to 0.3%, Cu: 0.05 to 0.4%, Mn: 0.05 to 0 .3%, Zr: 0.05 to 0.25%, Ti: 0 to 0.15%, the total of Zr and Ti is 0.3% or less, and the balance is Al and inevitable impurities Corrosion resistance, characterized in that the AlFeSi stable phase accounts for an area ratio of 0.1% or more and less than 0.5% among particles made of an aluminum alloy and dispersed in a matrix and having a particle area of 1.0 μm ² or more. describes extruded flat multi-hole tubes for heat exchangers which are excellent in

Japanese Patent Application Laid-Open No. 2009-46702

In recent years, due to the heightened environmental awareness, the importance of technology to reuse aluminum waste as casting raw material has increased. However, aluminum scrap contains various elements other than aluminum. In addition, the aluminum scrap may contain metallic materials other than aluminum, such as iron, in some cases. Therefore, when aluminum waste is reused as a raw material for casting, the content of elements other than aluminum increases, causing various problems such as an increase in deformation resistance during hot extrusion and a decrease in extrusion speed. rice field. Therefore, in the conventional technical level, it was considered difficult to produce an extruded multi-hole pipe having a complicated cross-sectional shape when aluminum waste material was used as a casting raw material.

The present invention has been made in view of such a background, and provides a method for manufacturing an extruded multi-hole tube that can be easily hot-extruded even when the content of elements other than aluminum is relatively high. I am trying to.

One aspect of the present invention includes Si (silicon): 2.00 mass % or less, Fe (iron): 0.60 mass % or less, Cu (copper): 0.60 mass % or less, Mn (manganese): 2.00 mass % or less. 00% by mass or less, Mg (magnesium): 0.40% by mass or less, Cr (chromium): 0.10% by mass or less, Zn (zinc): 1.50% by mass or less, Ti (titanium): 0.10% by mass % or less and B (boron): contains one or more elements selected from the group consisting of 0.10% by mass or less, the balance being Al (aluminum) and unavoidable impurities, and the content of Si and the Mn content is 3.20% by mass or less, and the Si content is less than the Mn content.
The ingot is held at a temperature of 550 ° C. or higher and 650 ° C. or lower for 2 hours or more to perform a first homogenization treatment,
After that, the ingot is held at a temperature of 450 ° C. or higher and 540 ° C. or lower for 3 hours or more to perform a second homogenization treatment,
After that, the ingot is subjected to hot extrusion to produce an extruded multi-hole pipe.

In the manufacturing method of the extruded multi-hole pipe, the ingot having the chemical composition within the specific range is subjected to the first homogenization treatment and the second homogenization treatment. In this way, the homogenization treatment is performed in two stages, and the holding temperature and holding time of the homogenization treatment in each stage are set within the specific ranges described above, so that even when the content of elements other than aluminum is relatively large, Even if there is, an increase in deformation resistance during hot extrusion can be suppressed.

As described above, according to the above aspect, it is possible to provide a method for manufacturing an extruded multi-hole tube that can easily perform hot extrusion even when the content of elements other than aluminum is relatively large. can.

1 is a perspective view of an extruded multi-hole tube in Example 1. FIG.

In the manufacturing method of the extruded multi-hole pipe, first, an ingot having the specific chemical composition is produced. The ingot contains one or more elements selected from the group consisting of Si, Fe, Cu, Mn, Mg, Cr, Zn, Ti and B. These elements are contained in casting raw materials such as aluminum ingots, aluminum scraps, and intermediate alloys. When aluminum waste is used as the casting raw material, the elements mentioned above may be mainly derived from the aluminum waste.

- Si: 2.00% by mass or less The ingot may contain more than 0% by mass and 2.00% by mass or less of Si. Si is an element contained in aluminum base metals, aluminum alloys containing Si (for example, 4000 series alloys and 6000 series alloys, etc.) in aluminum scraps, intermediate alloys, and the like. Si has the effect of improving the strength of the extruded multi-hole pipe. From the viewpoint of further improving the strength of the extruded multi-hole tube, the Si content is preferably 0.20% by mass or more, more preferably 0.40% by mass or more, and more preferably 0.60% by mass. It is more preferably 0.70% by mass or more, particularly preferably 0.70% by mass or more, and most preferably 0.80% by mass or more.

On the other hand, if the Si content is excessively high, the deformation resistance of the ingot during hot extrusion increases, which may lead to a decrease in extrudability. By setting the Si content to 2.00% by mass or less, preferably 1.50% by mass or less, more preferably 1.40% by mass or less, and even more preferably 1.30% by mass or less, during hot extrusion It is possible to improve the strength of the extruded multi-hole pipe while suppressing an increase in the deformation resistance of the ingot.

· Mn: 2.00% by mass or less Mn may be contained in an ingot in an amount of more than 0% by mass and 2.00% by mass or less. Mn is an element contained in aluminum base metals, aluminum alloys containing Mn in aluminum scraps (for example, 3000 series alloys, etc.), intermediate alloys, and the like. Mn has the effect of improving the strength of the extruded multi-hole pipe. From the viewpoint of further improving the strength of the extruded multi-hole tube, the Mn content is preferably 0.40% by mass or more, more preferably 0.60% by mass or more, and more preferably 0.80% by mass. It is more preferably 0.90% by mass or more, particularly preferably 0.90% by mass or more, and most preferably 1.00% by mass or more.

On the other hand, if the Mn content is excessively high, the deformation resistance of the ingot during hot extrusion increases, which may lead to a decrease in extrudability. By setting the Mn content to 2.00% by mass or less, preferably 1.80% by mass or less, and more preferably 1.70% by mass or less, an increase in deformation resistance of the ingot during hot extrusion is suppressed. At the same time, the strength of the extruded multi-hole tube can be improved.

In addition, the sum of the Si content and the Mn content in the ingot is 3.20% by mass or less, and the Si content is less than the Mn content. In the chemical composition of the ingot, in addition to setting the Si and Mn contents within the specific ranges, the Si content and the Mn content satisfy the above-described relationship, so that during hot extrusion It is possible to more effectively suppress the increase in deformation resistance of the ingot, and easily produce an extruded multi-hole pipe having a complicated cross-sectional shape. From the viewpoint of enhancing the above-described effect, the total content of Si and Mn is preferably 3.00% by mass or less.

If the sum of the Si content and the Mn content exceeds 3.20% by mass, the extrudability during hot extrusion may deteriorate. Also, if the Si content is greater than or equal to the Mn content, it becomes difficult to deposit fine AlMnSi-based intermetallic compounds in the ingot, which may lead to deterioration in extrudability. Moreover, in this case, the extrusion limit speed tends to decrease, which may lead to a decrease in the productivity of the extruded multi-hole tube. When the ingot is produced, if the total amount of Mn contained in the aluminum ingot and the aluminum scrap is less than or equal to the total amount of Si, an intermediate alloy containing Mn is added. Chemical composition can be adjusted.

- Fe: 0.60% by mass or less The ingot may contain more than 0% by mass and 0.60% by mass or less of Fe. Fe is an element contained in aluminum ingots, aluminum scraps, and the like. In particular, aluminum scraps sometimes contain parts made of Fe-based alloys, and when such aluminum scraps are used as casting raw materials, the Fe content in the ingot tends to increase. The Fe content is preferably 0.10% by mass or more, more preferably 0.15% by mass or more, still more preferably 0.20% by mass or more, and particularly preferably 0.25% by mass or more. It is possible to make it easier to increase the ratio of the aluminum waste material in the inside.

On the other hand, if the Fe content is excessively high, coarse AlFe-based intermetallic compounds tend to be formed in the ingot. A coarse AlFe-based intermetallic compound in the ingot is not preferable because it may lead to deterioration of the surface properties of the extruded multi-hole pipe, such as an increase in surface roughness. By setting the Fe content to 0.60% by mass or less, preferably 0.50% by mass or less, deterioration of the surface properties can be avoided.

·Cu: 0.60% by mass or less The ingot may contain more than 0% by mass and 0.60% by mass or less of Cu. Cu is an element contained in aluminum ingots, aluminum scraps, and the like. In particular, aluminum scrap may contain parts made of an aluminum alloy containing a large amount of Cu (for example, a 2000 series alloy), and when such aluminum scrap is used as a casting raw material, The content of Cu tends to increase. Cu has the effect of enhancing the natural potential of the extruded multi-hole pipe and improving the corrosion resistance of the extruded multi-hole pipe. From the viewpoint of further improving the corrosion resistance of the extruded multi-hole pipe, the Cu content is preferably 0.05% by mass or more, more preferably 0.10% by mass or more, and more preferably 0.15% by mass. It is more preferably 0.20 mass % or more, particularly preferably 0.20 mass % or more. Moreover, in this case, it is possible to easily increase the proportion of the aluminum scrap in the raw material for casting.

On the other hand, if the Cu content is excessively high, the amount of dissolved Cu in the ingot increases, which may lead to an increase in the deformation resistance of the ingot during hot extrusion and a decrease in extrudability. By setting the Cu content to 0.60% by mass or less, preferably 0.40% by mass or less, the corrosion resistance of the extruded multi-hole pipe is improved while suppressing an increase in the deformation resistance of the ingot during hot extrusion. can be made

- Mg: 0.40% by mass or less The ingot may contain more than 0% by mass and 0.40% by mass or less of Mg. Mg is an element contained in aluminum ingots, aluminum scraps, and the like. In particular, aluminum scraps may contain parts made of aluminum alloys containing a large amount of Mg (e.g., 5000 series alloys and 6000 series alloys). , the Mg content in the ingot tends to increase. Mg has the effect of improving the strength of the extruded multi-hole tube. From the viewpoint of further improving the strength of the extruded multi-hole tube, the Mg content is preferably 0.03% by mass or more, more preferably 0.05% by mass or more, and more preferably 0.07% by mass. It is more preferable that it is above. Moreover, in this case, it is possible to easily increase the proportion of the aluminum scrap in the raw material for casting.

On the other hand, if the Mg content is excessively high, the amount of Mg solid-dissolved in the ingot increases, which may lead to an increase in the deformation resistance of the ingot during hot extrusion and a decrease in extrudability. By setting the Mg content to 0.40% by mass or less, preferably 0.30% by mass or less, an increase in deformation resistance of the ingot during hot extrusion can be suppressed.

- Cr: 0.10% by mass or less The ingot may contain more than 0% by mass and 0.10% by mass or less of Cr. Cr is an element contained in aluminum ingots, aluminum scraps, and the like. In particular, aluminum scraps sometimes contain parts made of aluminum alloys containing a large amount of Cr (e.g., 5000 series alloys and 7000 series alloys). is likely to increase the Cr content in the ingot. By setting the Cr content to preferably 0.01% by mass or more, more preferably 0.02% by mass or more, and even more preferably 0.03% by mass or more, the proportion of aluminum scrap in the raw material for casting can be increased. can be made easier.

On the other hand, if the Cr content is excessively high, coarse AlCr-based intermetallic compounds are likely to be formed in the ingot. The presence of coarse AlCr-based intermetallic compounds in the ingot is not preferable because cracks may easily occur during hot extrusion or secondary processing after hot extrusion. By setting the Cr content to 0.10% by mass or less, formation of coarse AlCr-based intermetallic compounds can be avoided.

- Zn: 1.50% by mass or less The ingot may contain more than 0% by mass and 1.50% by mass or less of Zn. Zn is an element contained in aluminum ingots, aluminum scraps, and the like. In particular, aluminum scrap may contain parts made of aluminum alloys containing a large amount of Zn (for example, 7000 series alloys, etc.). The content of Zn in the inside tends to increase. Zn weakens the surface oxide film of the extruded multi-hole pipe and disperses the occurrence of pitting corrosion, thereby improving corrosion resistance. From the viewpoint of further enhancing such effects, the Zn content is preferably 0.05% by mass or more, more preferably 0.10% by mass or more, and 0.15% by mass or more. is more preferred. Moreover, in this case, it is possible to easily increase the proportion of the aluminum scrap in the raw material for casting.

On the other hand, if the Zn content is excessively high, the solidus temperature of the aluminum alloy will decrease, which may cause partial melting of the ingot or extruded multi-hole tube during homogenization or hot extrusion. be. By setting the Zn content to 1.50% by mass or less, preferably 1.00% by mass or less, the effects of Zn can be obtained while avoiding partial melting of the ingot or extruded multi-hole pipe.

- Ti: 0.10% by mass or less The ingot may contain more than 0% by mass and 0.10% by mass or less of Ti. Ti has the effect of refining the crystal grains in the metal structure of the ingot. From the viewpoint of further enhancing such effects, the Ti content is preferably 0.005% by mass or more, more preferably 0.007% by mass or more, and more preferably 0.010% by mass or more. More preferred.

On the other hand, if the Ti content is excessively high, coarse AlTi-based intermetallic compounds tend to be formed in the ingot. The presence of coarse AlTi-based intermetallic compounds in the ingot is not preferable because cracks may easily occur during hot extrusion or secondary processing after hot extrusion. By setting the Ti content to 0.10% by mass or less, it is possible to sufficiently refine the crystal grains in the metal structure of the ingot while avoiding the formation of coarse AlTi-based intermetallic compounds.

·B: 0.10% by mass or less The ingot may contain more than 0% by mass and 0.10% by mass or less of B. By setting the content of B in the extruded multi-hole tube within the specific range, the crystal grains in the metal structure of the extruded multi-hole tube can be sufficiently refined. From the viewpoint of obtaining such effects more reliably, the content of B in the ingot is preferably 0.005% by mass or more and 0.10% by mass or less.

- Other elements The ingot may contain elements other than the elements described above as unavoidable impurities. Examples of such elements include Zr (zirconium) and V (vanadium). The content of elements as unavoidable impurities may be, for example, 0.05% by mass or less for each element. Also, the total content of elements as unavoidable impurities should be 0.50% by mass or less.

From the viewpoint of obtaining the effect of improving the extrudability described above more reliably, the ingot contains Si: 0.60% by mass or more and 1.40% by mass or less and Mn: 0.80% by mass or more and 1.80% by mass or less. The balance consists of Al and unavoidable impurities, the total of the Si content and the Mn content is 3.20% by mass or less, and the Si content is less than the Mn content Chemical component It is preferable to have In this case, the ingot further has Fe: 0.10% by mass or more and 0.50% by mass or less, Cu: 0.05% by mass or more and 0.40% by mass or less, Mg: 0.05% by mass or more and 0.30% by mass. % by mass or less, Cr: 0.01% by mass or more and 0.10% by mass or less, Zn: 0.10% by mass or more and 1.00% by mass or less, Ti: 0.005% by mass or more and 0.10% by mass or less and B : 1 or 2 or more elements selected from the group consisting of 0.005% by mass or more and 0.10% by mass or less may be included as optional components.

From the same point of view, the ingot has Si: 0.70% by mass or more and 1.30% by mass or less, Fe: 0.10% by mass or more and 0.50% by mass or less, Cu: 0.05% by mass or more and 0.40% by mass. % by mass or less, Mn: 0.90% by mass or more and 1.70% by mass or less, Mg: 0.05% by mass or more and 0.30% by mass or less, Cr: 0.01% by mass or more and 0.10% by mass or less, Zn : 0.10% by mass or more and 1.00% by mass or less, Ti: 0.005% by mass or more and 0.10% by mass or less, and B: 0.005% by mass or more and 0.10% by mass or less, and the balance is composed of Al and unavoidable impurities, the total of the Si content and the Mn content is 3.00% by mass or less, and the Si content is less than the Mn content. is preferred.

A known casting method such as DC casting or CC casting can be used to produce the ingot. As a raw material for casting when producing an ingot, for example, virgin aluminum metal or scrap aluminum can be used.

In the manufacturing method of the extruded multi-hole pipe, it is preferable to use aluminum waste material as at least part of the casting raw material. Here, the aluminum scrap includes offcuts and chips generated in the manufacturing process of aluminum products, used aluminum products, aluminum parts separated from used products, and the like.

As described above, when aluminum waste is reused as a raw material for casting, the content of elements other than aluminum increases, causing various problems such as an increase in deformation resistance during hot extrusion and a decrease in extrusion speed. was inviting Therefore, in the conventional technical level, it was considered difficult to produce an extruded multi-hole pipe having a complicated cross-sectional shape when aluminum waste material was used as a casting raw material.

On the other hand, in the method for manufacturing the extruded multi-hole pipe, the chemical composition of the ingot is set within the specific range, and then the two-stage homogenization treatment described later is performed to remove elements other than aluminum. Even when the content is relatively large, it is possible to suppress an increase in deformation resistance during hot extrusion. Therefore, according to the manufacturing method of the above aspect, even if aluminum waste material is used as at least a part of the casting raw material and the content of elements other than aluminum is relatively large, the casting material has a complicated cross-sectional shape. An extruded multi-hole tube can be easily produced.

Furthermore, by using aluminum waste as at least part of the casting raw material, the amount of new aluminum ingot used can be reduced. As a result, the environmental load in the manufacturing process of the extruded multi-hole pipe can be further reduced, and the material cost of the extruded multi-hole pipe can be further reduced. From the viewpoint of further enhancing such effects, the ratio of the aluminum waste material to the casting raw material is preferably 35% by mass or more, more preferably 45% by mass or more, and particularly preferably 60% by mass or more.

In the method for manufacturing an extruded multi-hole tube, after the ingot is produced, the ingot is held at a temperature of 550°C or higher and 650°C or lower for 2 hours or longer to perform a first homogenization treatment. By setting the holding temperature and holding time in the first homogenization treatment to the specific ranges, coarse crystallized substances in the ingot are decomposed, granulated, or redissolved in the Al matrix. can do.

From the viewpoint of further promoting the decomposition of crystallized substances in the ingot, the holding temperature in the first homogenization treatment is preferably 580°C or higher and 620°C or lower. From the same point of view, the holding time in the first homogenization treatment is preferably 10 hours or longer. Moreover, the retention time in the first homogenization treatment is preferably 24 hours or less from the viewpoint of productivity.

If the holding temperature in the first homogenization treatment is less than 550°C, or if the holding time is less than 2 hours, there is a risk that the decomposition of crystallized substances will be insufficient. If the holding temperature in the first homogenization treatment exceeds 650°C, the ingot may partially melt.

In the manufacturing method of the extruded multi-hole pipe, the ingot after the first homogenization treatment is subjected to the second homogenization treatment. The holding temperature in the second homogenization treatment is 450° C. or higher and 540° C. or lower, and the holding time is 3 hours or longer. As described above, the primary purpose of the first homogenization treatment is to decompose, granulate, and redissolve coarse crystallized substances crystallized in the ingot during casting. However, when the holding temperature and holding time in the first homogenization treatment are within the above-mentioned specific ranges, the decomposition, granulation, and re-dissolution of crystallized substances, as well as the solute elements Mn and Si into the Al matrix phase. Solid solution is also promoted. If the amount of the solute element dissolved in the Al matrix is excessively large, the movement speed of dislocations in the matrix during hot extrusion decreases, and the deformation resistance tends to increase.

On the other hand, when the ingot is heated under the specific conditions in the second homogenization treatment, the Si and Mn dissolved in the Al matrix phase in the first homogenization treatment are finely precipitated as AlMnSi-based intermetallic compounds. can be done. As a result, the solid solution amount of the solute element in the Al matrix can be reduced, and the deformation resistance during hot extrusion can be reduced. Therefore, the extrudability during hot extrusion can be improved by heating the ingot after the first homogenization treatment under the specific conditions and performing the second homogenization treatment.

From the viewpoint of enhancing the effect of improving extrudability, the holding temperature in the second homogenization treatment is preferably 480°C or higher and 520°C or lower. From the same point of view, the holding time in the second homogenization treatment is preferably 5 hours or more. Moreover, the holding time in the second homogenization treatment is preferably 24 hours or less, more preferably 15 hours or less, from the viewpoint of productivity.

If the holding temperature in the second homogenization treatment is less than 450 ° C., or if the holding time is less than 3 hours, the amount of precipitation of the AlMnSi-based intermetallic compound tends to decrease, and the extrudability during hot extrusion deteriorates. may lead to When the holding temperature in the second homogenization treatment exceeds 540 ° C., it becomes difficult for Si and Mn dissolved in the Al matrix to form an intermetallic compound, which may lead to deterioration of extrudability during hot extrusion. There is

In the manufacturing method, the first homogenization treatment and the second homogenization treatment can be performed continuously. Here, performing the first homogenization treatment and the second homogenization treatment continuously means that after the first homogenization treatment is completed, the temperature of the ingot is lowered to the holding temperature in the second homogenization treatment, It refers to starting the second homogenization treatment when the temperature of the ingot reaches the holding temperature in the second homogenization treatment.

When the first homogenization treatment and the second homogenization treatment are performed continuously, after the first homogenization treatment is completed, the second homogenization is performed at an average cooling rate of 20 ° C./hour or more and 60 ° C./hour or less. It is preferable to cool the ingot to the holding temperature in the hardening treatment.

Further, in the manufacturing method, after the first homogenization treatment is completed, the ingot can be once cooled to a temperature lower than the holding temperature in the second homogenization treatment, and then the second homogenization treatment can be performed. In this case, the temperature of the ingot at the completion of cooling can be, for example, 200° C. or less. When heating the ingot after cooling to the holding temperature in the second homogenization treatment, the ingot is heated to the holding temperature in the second homogenization treatment at an average temperature increase rate of 20 ° C./hour or more and 60 ° C./hour or less. preferably.

In the manufacturing method of the extruded multi-hole pipe, the extruded multi-hole pipe can be obtained by subjecting the ingot after the second homogenization treatment to hot extrusion. In hot extrusion, the temperature of the ingot at the start of extrusion and the temperature of the extruded multi-hole tube at the end of extrusion may be appropriately set according to the chemical composition of the extruded multi-hole tube. For example, the temperature of the ingot at the start of extrusion can be appropriately set within the range of 450°C or higher and 550°C or lower. The extruded multi-hole pipe obtained in this way may be used as it is, or may be straightened or cut to adjust the size and shape, heat treated to adjust strength, zinc sprayed to improve corrosion resistance, or painted. You may use it after performing post-processing, such as. These post-treatments can be appropriately combined according to the use of the extruded multi-hole pipe.

The extruded multi-hole tube obtained by the manufacturing method has an outer wall section that separates an outer space from the inside of the extruded multi-hole tube, and a plurality of partition walls that separate the inner space of the outer wall section. In addition, the extruded multi-hole tube has a plurality of passages surrounded by the outer wall portion and the partition wall portion, and is configured such that liquid, gas, etc. can be circulated through these passages. The cross-sectional shape of the extruded multi-hole tube is not particularly limited, and can have various cross-sectional shapes such as an oval shape and a rectangular shape. Also, the cross-sectional shape of the passage of the extruded multi-hole tube is not particularly limited, and can have various cross-sectional shapes such as circular, triangular, and quadrangular.

The extruded multi-hole tube may have a flat cross-sectional shape. In this case, the ratio of the width to the thickness of the extruded multi-hole tube can be 2 or more and 50 or less, preferably 3 or more and 30 or less. In general, when the extruded multi-hole tube has a flat shape, the higher the ratio of the width to the thickness, the more difficult it is to extrude, and there is a tendency that high extrudability is required. In the process of manufacturing the extruded multi-hole tube, the aluminum alloy ingot having the specific chemical composition is subjected to two-stage homogenization treatment to suppress the increase in deformation resistance during hot extrusion and improve the extrudability. can be enhanced. Therefore, it is possible to easily obtain an extruded multi-hole tube having a cross-sectional shape that requires such high extrudability.

In addition, the extruded multi-hole pipe has an outer wall portion that separates an outer space from the inside of the extruded multi-hole pipe, and a plurality of partition walls that separate the inner space of the outer wall portion. The partition wall may have a thickness of 0.10 mm or more and 2.0 mm or less, preferably 0.15 mm or more and 1.5 mm or less. As with the width-to-thickness ratio described above, in extruded multi-hole pipes, the thinner the outer wall portion and the partition wall portion, the more difficult the extrusion process becomes, and there is a tendency that high extrudability is required. In the process of manufacturing the extruded multi-hole tube, the aluminum alloy ingot having the specific chemical composition is subjected to two-stage homogenization treatment to suppress the increase in deformation resistance during hot extrusion and improve the extrudability. can be enhanced. Therefore, it is possible to easily obtain an extruded multi-hole tube having a cross-sectional shape that requires such high extrudability.

An example of the method for manufacturing the extruded multi-hole pipe will be described below. In the method for producing an extruded multi-hole tube of this example, Si: 2.00% by mass or less, Fe: 0.60% by mass or less, Cu: 0.60% by mass or less, Mn: 2.00% by mass or less, Mg : 0.40% by mass or less, Cr: 0.10% by mass or less, Zn: 1.50% by mass or less, Ti: 0.10% by mass or less, and B: 0.10% by mass or less It contains one or more elements, the balance being Al and unavoidable impurities, the total of the Si content and the Mn content is 3.20% by mass or less, and the Si content is Mn to produce an ingot having a chemical composition less than the content of After that, the ingot is held at a temperature of 550° C. or more and 650° C. or less for two hours or more to perform a first homogenization treatment. After the first homogenization treatment is completed, the ingot is held at a temperature of 450° C. or more and 540° C. or less for 3 hours or more to perform a second homogenization treatment. Then, an extruded multi-hole pipe can be produced by subjecting the ingot after the completion of the second homogenization treatment to hot extrusion.

The extruded multi-hole tube 1 of this example has a flat cross-sectional shape, as shown in FIG. More specifically, the extruded multi-hole tube 1 has an oval cross-sectional shape. The width of the extruded multi-hole tube 1 is, for example, 14.0 mm, and the thickness is, for example, 2.5 mm.

In addition, the extruded multi-hole tube 1 has an outer wall portion 11 that separates the outer space from the inside, and a partition wall portion 13 that separates the space surrounded by the outer wall portion 11 into 19 passages 12 . The passage 12 of the extruded multi-hole tube 1 in this example has a circular cross-sectional shape. The thickness of the thinnest portion of the outer wall portion 11 and the partition wall portion 13 is, for example, 0.4 mm.

An example of the method for manufacturing the extruded multi-hole tube of this example will be described more specifically below. First, an ingot having chemical compositions (alloy symbols A1 to A3) shown in Table 1 is produced by DC casting using a casting raw material containing aluminum scrap. "Bal." in Table 1 is a symbol indicating that the element is the balance.

After producing the ingot, the ingot is held at a temperature of 600°C for 10 hours to perform a first homogenization treatment. After completing the first homogenization treatment, the ingot is held at a temperature of 500° C. for 10 hours to perform a second homogenization treatment. The first homogenization treatment and the second homogenization treatment may be performed continuously, or after the first homogenization treatment is completed and before the second homogenization treatment is performed, the temperature of the ingot is the second It may be below the holding temperature in the homogenization treatment.

After the second homogenization treatment is completed, the extruded multi-hole tube 1 is produced by subjecting the ingot to hot extrusion while the temperature of the ingot is 500°C. As described above, the test materials S1 to S3 shown in Table 2 can be obtained. The test materials R1 to R4 shown in Table 2 are test materials for comparison with the test materials S1 to S3. The method for producing test materials R1 to R3 was the same as that for test materials S1 to S3, except that the chemical composition of the ingot was changed to alloy symbols A4 to A6 shown in Table 1. The method for producing test material R4 was the same as that for test materials S1 to S3, except that the chemical composition of the ingot was changed to alloy symbol A7 shown in Table 1 and the second homogenization treatment was omitted.

The method for evaluating the extrudability of each test material is explained below.

Extrudability Extrudability can be evaluated based on the appearance of the test material. More specifically, the appearance of the test material is visually observed to evaluate the presence or absence of cracks and streaky patterns along the extrusion direction. Table 2 shows the presence or absence of cracks and streaky patterns at the ends of each test material.

As shown in Tables 1 and 2, in the manufacturing process of the test materials S1 to S3, the ingot having the specific chemical composition is subjected to the first homogenization treatment and the second homogenization treatment under the specific conditions. Therefore, the deformation resistance of the ingot during hot extrusion can be reduced. Therefore, the test materials S1-S3 have a good appearance.

On the other hand, since the Si content of the test material R1 is greater than or equal to the Mn content, the extrudability of the test material R1 is inferior to the test materials S1 to S3, and streaky patterns are generated on the surface of the test material.
Since the total of the Si content and the Mn content of the test material R2 is excessively large, the extrudability is inferior to the test materials S1 to S3, and cracks occur at the ends in the width direction of the test material. , a streaky pattern occurs on the surface of the test material.

Since the content of Mn in the test material R3 is excessively high, the extrudability is inferior to the test materials S1 to S3, and streaky patterns are generated on the surface of the test material.
Since the test material R4 was not subjected to the second homogenization treatment in the manufacturing process, it was inferior to the test materials S1 to S3 in extrudability, and streaky patterns were generated on the surface of the test material.

The specific aspects of the method for producing an extruded multi-hole pipe according to the present invention have been described above based on the examples. The configuration is not limited, and the configuration can be appropriately changed within the scope of the present invention.

Claims

Si: 2.00% by mass or less, Fe: 0.60% by mass or less, Cu: 0.60% by mass or less, Mn: 2.00% by mass or less, Mg: 0.40% by mass or less, Cr: 0.10 Zn: 1.50% by mass or less, Ti: 0.10% by mass or less, and B: 0.10% by mass or less. consists of Al and unavoidable impurities, the sum of the Si content and the Mn content is 3.20% by mass or less, and the Si content is less than the Mn content. fabricate,
The ingot is held at a temperature of 550 ° C. or higher and 650 ° C. or lower for 2 hours or more to perform a first homogenization treatment,
After that, the ingot is held at a temperature of 450 ° C. or higher and 540 ° C. or lower for 3 hours or more to perform a second homogenization treatment,
Thereafter, a method for producing an extruded multi-hole pipe, wherein the ingot is subjected to hot extrusion to produce an extruded multi-hole pipe.
Extrusion according to claim 1, wherein after the first homogenization treatment is completed, the ingot is cooled to the holding temperature in the second homogenization treatment at an average cooling rate of 20 ° C./hour or more and 60 ° C./hour or less. A method for manufacturing a multi-hole pipe.
After the first homogenization treatment is completed, the ingot is cooled to a temperature lower than the treatment temperature in the second homogenization treatment, and then an average of 20 ° C./hour or more and 60 ° C./hour or less 2. The method for producing an extruded multi-hole pipe according to claim 1, wherein the ingot is heated at a temperature rising rate to a holding temperature in the second homogenization treatment.
The method for producing an extruded multi-hole pipe according to any one of claims 1 to 3, wherein aluminum waste material is used as at least a part of the casting raw material when producing the ingot.
5. The extruded multi-hole pipe according to any one of claims 1 to 4, wherein the hot extrusion produces the extruded multi-hole pipe having a flat cross-sectional shape and a ratio of width to thickness of 2 or more and 50 or less. A method for manufacturing an extruded multi-hole tube.
By the hot extrusion, it has an outer wall portion that separates an outer space and the inside of the extruded multi-hole tube, and a plurality of partition walls that separate the inner space of the outer wall portion, and the outer wall portion and the partition wall. The method for producing an extruded multi-hole tube according to any one of claims 1 to 5, wherein the extruded multi-hole tube having a thickness of 0.10 mm or more and 2.0 mm or less is produced.