DE112018000796T5 - Extruded flat perforated aluminum tube exhibiting excellent brazing properties and methods of making same - Google Patents

Abstract

The present invention effectively enhances the superior brazing properties of an outer surface of a flat extruded perforated aluminum tube and provides a method of inexpensively simple and advantageous production thereof. An extruded flat perforated aluminum tube 10 formed by simultaneously extruding an aluminum tube main body material and a brazing material comprising an Al-Si based aluminum alloy, wherein a portion of the brazing material 18 is exposed by exposing the brazing material around the entirety of the outer tube peripheral wall portion or at least a portion of the flat portion of the outer tube peripheral wall portion is formed.

Description

TECHNICAL AREA

The present invention relates to a flat extruded aluminum tube having a plurality of openings, which has excellent brazeability, and a method of producing the same. More particularly, the invention relates to a flat extruded aluminum tube having a plurality of openings, which is advantageously used as a heat transfer tube in a heat exchanger, particularly in an automotive heat exchanger such as an automobile air conditioner. The tube is stably and economically provided with a brazing filler metal portion in its outer periphery, to which fins are brazed, such that the tube has a stable and uniform brazeability. The invention also relates to a method of advantageously producing the above-mentioned tube.

Conventionally, an extruded aluminum tube having a plurality of openings having a substantially flat cross-sectional shape and obtained by extruding an aluminum material is used as a refrigerant passageway for a heat exchanger used in automobiles, and a refrigerant is sent through the refrigerant passageway. Meanwhile, aluminum fins coated with an aluminum brazing filler metal are soldered to the refrigerant passageway in the direction perpendicular to the tube and fixed thereto to form a heat exchanger, and air as a heat exchanging fluid is sent along the aluminum fins. Thus, a heat exchange between the refrigerant and the air takes place. The aforementioned flat extruded aluminum multi-port tube is typically assembled with aluminum fins, each formed of a brazing sheet clad with an Al-Si based fill alloy, in a brazing process that is a flux 1 as, or a fluxless brazing operation such as a vacuum process and a brazing operation under atmosphere.

Meanwhile, demands have been made for the aluminum fins to be thinner so that an aluminum heat exchanger can become lighter. If it is possible to use a loose material instead of the brazing sheet, which is contrary to the known case, and to cover the tube with a brazing filler metal, it is expected that the fins could be further thinned. However, hitherto, a method of stably and economically covering flat extruded aluminum multi-ported tubes with the filler metal has not been industrially produced.

Some methods that apply the covering of the flat extruded aluminum tube having a plurality of openings with the filler metal are in the JP 6-504485 A and in the JP 7-308795 A for example suggested. In these methods, the flat extruded aluminum multi-aperture tubes are dipped or coated in a mixture of flux and silicon metal powder, then are heated and dried to cover their outer surface with the mixture. The tube is assembled with the bare fins and subjected to heating for alloying in a brazing furnace, so that brazing of the tube and the fin is complete by forming an Al-Si based molten filler metal on its joining surfaces. However, the above-mentioned methods have problems in that the production cost increases due to the complexity of the coating or covering process, and the uniform and stable joining by brazing is unlikely to be achieved because the uniform covering of the tube is difficult, and also the sticking of the Si powder to the tube tends to be insufficient. In addition, the reveals JP 2002-172485 A a method of thermally spraying the filler onto the flat extruded aluminum tube with multiple openings. However, this technique also does not allow the tube to be uniformly covered with the filler metal, and has an inherent problem of increasing the manufacturing cost, as the technique requires the introduction of additional equipment. In order to solve the above-mentioned problems, the use of a flat extruded aluminum tube having the filler metal stably and uniformly coated on its outer surface is considered to be effective.

As the flat extruded tube having a plurality of openings, a tube obtained by chamber extrusion of an aluminum or an aluminum alloy is typically used. In this regard, the JP 10-258356 A a technique of coating the filler metal on the flat extruded tube having a plurality of openings at the time of extrusion, although the technique has a problem that the coated filler metal layer is caught in opposite side portions of the flat extruded multi-port tube, which easily entrap the resin Fill metal into the tube results. The JP 10-197175A suggests to form protrusions in the opposite side portions of a tube in order to solve the above-mentioned problem. However, in this technique, one is Form of the tube due to the formation of the projections in the opposite side portions of the flat extruded tube with a plurality of openings limited so that the versatility of the tube is greatly reduced.

In addition, the beats JP 63-97309 A a method in which a composite billet formed of an aluminum core element material and a skin member material formed of an Al-Si based aluminum filler metal is coextruded to produce a coated tube that coats a filler metal layer on an outer flat portion of its peripheral wall having. However, the above-mentioned coated tube also has inherent problems such as the inclusion of the filling metal layer in a welded portion, and this problem may be caused due to even slight deviation of a relative position between the composite billet and a chamber die, and the deviation is caused by a Influence of metal flow on the skin element material causes.

PRINT DESCRIPTION OF THE PRIOR ART

PATENT DOCUMENTS

• Patent Document 1: JP 6-504485 A
• Patent Document 2: JP 7-308795 A
• Patent Document 3: JP 2002-172485 A
• Patent Document 4: JP 10-258356 A
• Patent Document 5: JP 10-197175A
• Patent Document 6: JP 63-97309 A

SUMMARY OF THE INVENTION

TECHNICAL PROBLEMS

Under these circumstances, the inventors have made a thorough investigation to stably and economically provide the Al-Si based filler metal layer that forms the molten filler metal on the outer surface of the flat extruded aluminum multi-port aluminum tube obtained by extruding the aluminum material Aluminum elements, such as the aluminum fins are joined to the outer peripheral wall portion of the tube. As a result, it has been found that the aluminum fill metal of the Al-Si based alloy is advantageously exposed in the outer peripheral wall portion of the flat extruded multi-port aluminum tube by pressing a known aluminum tube core material and the aluminum fill metal of the Al-Si based alloy as the strand Aluminum materials are provided and at the same time such aluminum materials are hot-pressed. The inventors have also found that the inclusion of the filling metal layer in the opposite side portions of the flat tube having a plurality of openings to be obtained can be effectively obtained by providing a predetermined front disk on a front side of a composite billet in the direction of hot extrusion of the composite billet consists of the aluminum tube core material and the Al-Si based aluminum cooling metal. The method also has a high degree of versatility because it can be applied to the production of flat extruded multi-port tubes in general. Thus, it has been found that the uniform filler metal layer can be easily and economically exposed in the flat tube having a plurality of openings according to the above-mentioned method without a problem of confining the filling metal layer due to the formation of the tube.

The present invention has been completed in consideration of the above-described findings. It is therefore a problem to be solved by the invention to easily and economically provide an extruded tube having a plurality of openings with a substantially flat cross-sectional shape obtained by extruding an aluminum material, and the tube is configured to have an excellent brazeability of an outer surface to enable. It is another problem to be solved by the invention to provide a method of advantageously producing the flat extruded aluminum tube having a plurality of openings exhibiting the excellent characteristic as described above.

SOLUTION OF PROBLEMS

The above-mentioned problem can be solved, according to a quintessence of the invention, to provide an aluminum tube having a plurality of openings with a substantially flat cross-sectional shape obtained by extruding an aluminum material, the multi-port aluminum tube being an extruded tube comprising a tube A plurality of flow passages extending independently of each other in parallel with an axial direction of the tube and the flow passages are arranged in a longitudinal direction of the flat cross sectional shape via inner partition wall portions extending in the axial direction of the tube, characterized in that: the aluminum tube with a plurality of openings is formed by an extrusion process in which an aluminum tube core material and an aluminum filler metal of an Al-Si based aluminum alloy are used as the aluminum material; the aluminum filler metal is exposed to form a filler metal portion in the entirety of an outer peripheral wall portion of the tube or in at least a part of a flat portion of the outer peripheral wall portion; and the filling metal portion provided in the outer peripheral wall portion has a length of 50% to 100% of an outer peripheral length of the outer peripheral wall portion in the cross section of the tube and has a thickness of not more than 90% of a thickness of the peripheral wall portion has excellent brazeability.

In a preferred embodiment of the multi-hole aluminum tube having the excellent brazeability according to the invention, the aluminum filler metal comprises an aluminum alloy consisting of 1.0-13.0 mass% SI, at least one selected from the group consisting not more than 1.4% by mass Mn, 0.05-0.30% by weight Cr, 0.05-0.30% by mass Zr; 0.05-0.30 mass% Ti; and 0.0001-0.1 mass% Sr, with the remainder being aluminum and unavoidable impurities, and the aluminum tube core material comprising an aluminum alloy consisting of not more than 0.7 mass% Cu, not more than 1 4 mass% Mn, at least one selected from the group consisting of 0.05-0.30 mass% Cr, 0.05-0.30 mass% Zr, 0.05-0.30 mass% Ti and 0, 0001 - 0.1 mass percent Sr and the rest of aluminum and unavoidable impurities.

Moreover, in another preferred embodiment of the multi-hole aluminum tube having the excellent brazeability, according to the invention, the aluminum material to be extrusion-molded is a composite billet composed of the aluminum tube core material and the aluminum filler material.

Further preferably, in the invention, the composite billet has a one-piece shell core structure composed of a core billet formed of the aluminum tubular core material and a shell billet formed of the aluminum filler metal, and the shell billet is disposed to surround the core billet.

In addition, in an advantageous embodiment of the multi-port aluminum tube having the excellent brazeability according to the invention, the extruded tube is formed by extruding the aluminum material and using a chamber die.

In order to obtain the multi-port aluminum tube having the excellent brazeability according to the invention, the present invention also provides a method of producing the multi-port aluminum tube having the excellent brazeability, comprising the steps of providing a composite billet comprising the aluminum tube core material and the aluminum filler metal of the Al-Si based aluminum alloy, and a front disc formed of the same material as the aluminum tube core material and the front disc is configured to have a diameter of 90% to 100% of a diameter of the composite billet, and a Thickness of 5% to 30% of the diameter of the composite billet; Providing the front disk in a front side of the composite billet in an extrusion direction; and coextruding the front disk and the composite billet with a chamber die to hold the multi-port pipe.

In the process of producing the multi-port aluminum tube having the excellent brazeability according to the invention, the composite billet preferably has a one-piece sheath-core structure consisting of a core billet formed of the aluminum tubular core material and a sheath billet made of the aluminum filler metal is formed, and the shell billet is arranged to surround the core billet.

It is also a quintessential object of the invention to provide an aluminum heat exchanger comprising the aforementioned aluminum tube having a plurality of openings and aluminum outer fins brazed to an outer surface of the multi-port aluminum tube.

ADVANTAGEOUS EFFECTS OF THE INVENTION

The flat extruded aluminum multi-port tube according to the present invention has the filler metal portion formed of the aluminum filler metal, and the filler metal portion is exposed in the entirety of the outer surface of the tube or in at least a part of a flat portion of the outer tube without encapsulating the outer tube Fill metal layer to suffer in the widthwise opposite side portions of the cross section of the tube having a plurality of openings. Thus, the multi-port tube can be used as a heat transfer tube for a heat exchanger having excellent brazeability in the outer surface. Examples of the heat exchanger include a radiator and a heater.

In addition, since the flat extruded aluminum multi-port tube according to the invention comprises the aluminum tube core material and the aluminum filler metal material, and is directly produced by simultaneously extruding or coextruding the two materials, characteristics required for the tube are obtained by the aluminum tube core material the brazeability of the outer surface of the tube can be effectively improved by the aluminum filler metal. Thus, the freedom of designing the flat extruded multi-port extruded tube to be obtained is advantageously improved.

In addition, in the process of producing the flat extruded aluminum multi-port tube excellent in brazeability, according to the invention, the composite billet consisting of the aluminum tube core material and aluminum fill metal of the Al-Si based aluminum alloy simultaneously from the chamber tool (chamber die) with the the front face of the composite billet in the extrusion direction provided predetermined front disk is extruded, whereby the trapping of the Aluminiumfüllmetalls is effectively suppressed or prevented to the aluminum tubular core material. As a result, it is possible to advantageously obtain the flat extruded aluminum tube having a plurality of openings which is easy from the inclusion of the filling metal layer to the opposite side portions of the tube to be obtained, and which has stability and brazeability.

The flat extruded aluminum multi-port tube according to the invention is assembled and joined with aluminum outer fins (mere fins) by heating for brazing, so that the desired heat exchanger is easily and economically manufactured because the tube used in the heat exchanger has the aluminum filler residing on its surface Surface is exposed to obtain advantageous fixing of the outer fins in the tube by soldering.

list of figures

• The 1 10 are schematic cross-sectional views showing a flat extruded aluminum multi-port tube according to an embodiment of the present invention, in which FIGS 1 (a) is a cross-sectional view showing an entirety of the tube, the 1 (b) is an enlarged view, which shows a part of the central portion in the direction of the width of the tube, and the 1 (c) Fig. 11 is an enlarged view of a part of the end portion of the tube in the direction of the width, showing an example in which filler metal portions are exposed in different proportions;
• the 2 (a) and (b) are respective cross-sectional and longitudinal sectional views of the composite billet, and 2 (c) Fig. 4 is an explanatory view showing the longitudinal sectional view of the composite billet with a front disk provided adjacent to the composite billet; and
• 3 FIG. 4 are explanatory views of a one-component stick using an example in which FIG 3 (a) and (b) are respective transverse and longitudinal views of the composite billet, and 3 (c) Fig. 4 is an explanatory view showing the longitudinal sectional view of the one-component stick, and a front disk provided adjacent to the one-component stick.

MODE FOR CARRYING OUT THE INVENTION

In order to further clarify the present invention, representative embodiments of the invention will be described in detail with reference to the drawings.

With reference to the first schematic cross-sectional views of 1 For example, an example of a flat extruded aluminum multi-port tube according to this invention is shown in a transverse plane perpendicular to a longitudinal direction (axial direction) of the tube. Like from the 1 (a) The tube is visible 10 multi-orifice according to the invention comprises an extruded tube having a substantially flat cross-sectional shape made of an aluminum material and a plurality of flow passages 12 in the form of rectangular holes extending independently of each other in parallel with the axial direction of the tube, and the plurality of flow passages 12 is arranged at a predetermined distance in the direction of the width of the tube, namely in the longitudinal direction of the flat shape (left and right direction in the figures). The upper and lower opposite outer surfaces of the tube 10 with multiple openings are flat surfaces to the known outer fins (not shown in the figures) such. As disc fins and corrugated fins are used as a mere fins and by brazing, as described later, are joined, for example, to be used as a heat exchanger. While the cross-sectional shape of the flow passage 12 In this example, the rectangular shape, various other known forms such. As a circle, an oval, a triangle and combinations thereof may be used.

Like from the 1 (a) - (c) is clear in the invention is the flat tube 10 multi-ported structure having the above-mentioned structure configured such that a known aluminum tubing core material has a portion around each flow passage 12 forms, and the section an inner partition wall section 16 that's between the adjacent flow passages 12 . 12 is formed while a brazing filler metal section 18 made of an aluminum filler metal material present in at least a part of the flat portion, which is the above-mentioned flat surface of an outer peripheral wall portion 14 the tube determines, and partially the entire circumference of the outer peripheral wall portion 14 Are defined. This filling metal section 18 is in at least a part of the outer surface of the outer peripheral wall portion 14 uncovered (in the entirety of the scope in this example). Thus, a filler metal constituent contained in the aluminum filler metal, which enables the filling metal portion 18 determined around the outer peripheral wall portion 14 is formed, that the flat tube 10 with multiple openings to obtain, showing excellent brazeability.

Meanwhile, the above-mentioned filling metal portion 18 in at least a part of a flat portion of the outer surface (flat outer surface) of the outer periphery of the step 14 along an entire peripheral surface L in the cross section of the flat tube 10 exposed with several openings. Their exposed length is in a range of preferably 50%, more preferably 60%, and most preferably 70% to 100% of the total circumferential length L the tube. The exposure of the Füllmetallabschnitts 18 in a predetermined range of the entire circumferential length L The tube allows a stable and uniform exposure of the aluminum filler metal, which contributes to the excellent brazeability. In particular, the most desirable embodiment is in the 1 (a) shown in the filling metal section 18 along the entire total perimeter L the tube is formed. When the filling metal section 18 along a length of less than 50% of the circumferential length L the outer peripheral wall portion 14 is formed, it is likely that defects such as failure of joining the fins and peeling of the fins at the time of heating for brazing are caused. It is noted that the filling metal portion 18 that runs along the entire peripheral surface L the tube is exposed, not necessarily required to have a constant thickness. Such as from the 1 (c) it can be seen, the Füllmetallabschnitt 18 in the outer peripheral wall section 14 is exposed, thicknesses in different proportions with respect to the thickness of the outer peripheral wall portion 14 respectively. Although the filling metal section 18 preferably continuously along the entire circumferential length L Moreover, it is acceptable for the tube to be exposed 18 partially not continuous along the entire peripheral surface L the tube is exposed or exposed to a desired length so as to extend in the axial direction of the tube at a plurality of positions in the circumferential direction of the tube.

Like from the 1 (a) is clear, in the invention, the flat tube 10 with a plurality of openings having the above-mentioned structure, configured such that the filling metal portion 18 in the surface of the outer peripheral wall portion 14 along the entirety of the outer circumference of the tube or along at least part of the flat portion in the peripheral wall portion (along the entirety of the circumference in this example) is exposed. On the other hand, a known aluminum tube core material is present in sections where the filler metal section is not exposed, namely sections around each flow passage 12 with an inner partition wall section 16 that is between the adjacent flow passages 12 . 12 is trained. As can be seen from the figure, the outer peripheral wall portion determines 14 an outer peripheral wall of the flat tube 10 with multiple openings, and serves as an external partition for each of the flow passages 12 , Like from the 1 (b) apparent is, has the Füllmetallabschnitt 18 located in the outer peripheral wall section 14 is formed, preferably a thickness Ta of not more than 90% and preferably not more than 80% of a thickness ts the outer peripheral wall portion 14 on. A desirable lower limit of thickness Ta is 1%, and more preferably 5% of the thickness ts , Namely, it is to be said that Ta ≦ 0.9 × Ts, and preferably Ta ≥ 0.01 × Ts. When the thickness of the filling metal portion is 90% and the thickness ts the outer peripheral wall portion 14 exceeds, the outer peripheral wall portion 14 due to melting of the filler metal portion 18 At the time of heating for brazing, too thin, resulting in problems such as deterioration of the pressure resistance of the multi-port flat tube. In summary, in the exterior of the outer peripheral wall portion allows 14 provided filling metal section 18 in that the aluminum filler metal is in the outer surface of the outer peripheral wall portion 14 is exposed so that the tube advantageously enjoys outstanding brazeability on its outer surface.

In the above-mentioned flat tube 10 with multiple openings according to the invention that is the filling metal section 18 aluminum filler metal Al-Si based aluminum alloy, advantageously containing 1.0-13.0 mass% Si, at least one selected from the group consisting of not more than 1.4 mass% excluding 0 mass% Mn, 0.05 0.30 mass% Cr, 0.05-0.30 mass% Zr, 0.05-0.30 mass% Ti and 0.0001-0.1 mass% Sr, and the balance aluminum with unavoidable impurities such as Cu, Zn and Fe , When a content of Si exceeds 13.0 mass%, a melting point of the alloy rapidly decreases, resulting in a problem that a base material ends up from brazing at the time of heating to brazing. On the other hand, if the content of Si is less than 1 mass%, a problem of deterioration of brazability arises. When the content of Mn exceeds 1.4 mass%, a deformation resistance of the alloy at the time of extrusion increases, resulting in a difficulty in enabling high-speed extrusion, and also occurrence of a receiving defect at the time of high-speed extrusion. Cr, Zr, Ti and Sr are alloying ingredients that increase the crystal grain size of the alloy after brazing to improve the brazeability of the alloy. If their contents are smaller than the lower limits of the ranges defined above, the intended effects of the alloying ingredients can not be obtained. On the other hand, if their contents exceed the upper limit of the ranges, the production of coarse-grained composites in the extruding material obtained by casting becomes excessive, giving rise to problems such as deterioration in the easiness of extruding the material. It is noted that the lower limit of the content of Mn which is an alloying ingredient preferably present in the Al-Si-Zn based aluminum alloy is generally about 0.1 mass%.

In the above-mentioned flat tube 10 With a plurality of openings, known aluminum materials as used in the production of the flat extruded multi-port tube may be used as the aluminum tubular core material other than the aluminum filler metal and at least part of the outer peripheral wall section 14 certainly. For example, materials such as 1000 series pure aluminum and 3000 series aluminum alloy according to JIS can be used. In addition, a predetermined amount of Cu may be contained in the aluminum material as an alloying ingredient to increase the potential of the aluminum material. Among the above-mentioned tube core materials, an aluminum alloy containing more than 0.7% excluding 0% by mass of Cu, not more than 1.4% excluding 0% by mass of Mn, at least one selected from the group consisting of 0, is used. 05-0.30 mass% Cr, 0.05-0.30 mass% Zr, 0.05-0.30 mass% Ti and 0.0001-0.1 mass% Sr, and the balance of aluminum and unavoidable impurities such as Si , Fe and Zn exist. When the content of Cu exceeds 0.7 mass%, the deformation resistance of the alloy increases at the time of extrusion, resulting in difficulty in permitting high-speed extrusion, and moreover, the occurrence of a receiving defect at the time of high-speed extrusion. In addition, when the content of Mn exceeds 1.4 mass%, as in the case of Cu, the deformation resistance of the alloy increases at the time of extrusion, which results in difficulty in enabling extrusion at high speed, and also in the occurrence of the recording defect the time of extrusion at high speed. Cr, Zr, Ti and Sr are alloying ingredients that increase the crystal grain size of the alloy after being dissolved, thereby improving the brazeability of the alloy. If their contents are smaller than the lower limits of the ranges defined above, the desired effects of the alloy components can not be obtained. On the other hand, if their contents exceed the front limits of the ranges, the production of coarse grains connected in the material for extrusion, which is obtained by casting, appears in advance, which causes problems such as deterioration of the easiness of extrusion of the material. It is noted that the lower limit of the content of Cu in Generally, about 0.1% by mass, and the lower limit of the content of Mn is generally 0.1% by mass.

The aluminum filler metal material and the aluminum core material which determine the above-mentioned multi-opening tubes contain the rest of the aluminum and the impurities containing various elements such as Fe and Zn, which are inevitably included during the production of the alloys, in addition to those described above mentioned alloying components. The total content of unavoidable impurities is controlled to be within the generally recognized range. For example, the content is controlled to be not more than 0.5% by mass, and preferably not more than 0.3% by mass.

In the production of the above-mentioned flat tube 10 multi-apertures according to the invention, the above-mentioned aluminum tube core material and the aluminum filler metal are used as the aluminum materials, and these aluminum materials are subjected to coextrusion. Generally, the aluminum tube core material and the aluminum filler metal material are provided in the form of a composite billet having a sheath-core structure or a combination of multiple billets. In particular, the composite billet has a structure in which the aluminum tube core material is provided in the interior (a central portion) of the aluminum filler metal billet. The aluminum tube core material has a cross-sectional shape such. As a circle, an oval, an ellipse, a rectangle, a semicircle, a crescent moon and a polygon, optimized with their cross-sectional dimensions. The aluminum filler metal material and the aluminum tube core material are united by welding or other joining method such that a shell portion made of the filler metal is formed around a core portion made of the aluminum tube core material.

To manufacture the composite billet, the following various known methods can be employed: a method in which a shell billet is obtained by providing a through hole of a predetermined size in a central part of a billet formed of the aluminum filler metal material, and inserting a through hole into the through hole Aluminum core core material is formed core billet is introduced and assembled with the Mantelknüppel; and a method in which the sheath billet described above is divided into two pieces, the core billet is placed in a hollow portion defined by the two pieces, and all the above-mentioned members are fixed by a joining method such as welding or another joining method and be connected with each other.

The 2 (a) and (b) show an example of the above-mentioned composite billet. In the figures, a composite billet 20 a structure in which a cylindrical Füllmetallknüppel (Füllspielnüppel) 24 in one piece around the outer surface of a tube core billet (core billet) 22 is arranged in the form of a column around.

In addition, the composite billet described above becomes 20 as in the case of the conventional production of a flat tube with a plurality of openings using a so-called chamber shape (chamber die, chamber tool) with a plurality of extrusion openings subjected to hot extrusion, so as to produce the desired flat tube 10 to achieve with multiple openings. When the hot extrusion is performed, the composite billet becomes 20 arranged such that the longitudinal direction in the predetermined cross-sectional shape of the aluminum tubular core material ( 22 ) inside the composite billet ( 20 ) is placed, with respect to the mold with the longitudinal extrusion openings, that of the plurality of flow passages 12 the flat tube 10 correspond with a plurality of openings, coincides with the longitudinal direction of the extrusion openings of the mold. In this way, the composite billet ( 20 ) subjected to hot extrusion. The extrusion process of the composite billet described above 20 with the chamber shape allows an effective distribution of the filler metal material ( 24 ) within the composite billet ( 20 ) are provided as far as the outer circumference of the flat cross-sectional shape of the thus-obtained tube having a plurality of openings, so that the filling metal portion is advantageously exposed on the outer surface of the tube.

However, if the desired flat tube 10 multi-orifice die by hot extrusion of the above-mentioned composite billet 20 is produced from the chamber die according to the known method, the Füllmetallknüppel 24 that surrounds the outer surface of the composite billet 20 is arranged in the tube core billet 22 be caught up within the composite billet 20 is arranged so that the filling metal section 18 in the flat tube 10 with multiple openings to be made, likely to suffer from trapping in the aluminum tubing core material, which is the outer one Peripheral wall section 14 the tube determines. An enclosed portion of the filler metal section 18 may be subject to progress of corrosion, resulting in leakage of the liquid from the tube when the tube is used as a heat exchanger after being assembled with the fins.

Like from the 2 (c) can be seen, the present invention employs a method in which a predetermined front disc. Considering the above 26 in the form of a circular disk at the front end (front side) of the composite billet 20 in its extrusion direction integral with the composite billet 20 is provided, and the front disk 26 and the composite billet 20 be extruded from the chamber die. As such, the inclusion of the filler metal portion 18 to the opposite side portions of the flat tube 10 with multiple openings to be produced, effectively suppressed or prevented.

The above-mentioned extrusion process using the front disk 26 namely with a round or circular front disc 26 made of the same materials as the aluminum tube core material, for example, by welding to the end portion of the composite billet 20 is attached. It is noted that the front disc 26 a diameter of 90% to 100% of the diameter of the composite billet 20 having. If the diameter of the front disc 26 greater than 100% of the diameter of the composite billet 20 is here can create a problem that the composite billet 20 is caught in a container when the composite billet 20 is inserted into the container, so that the extrusion can not be performed, for example. On the other hand, if the diameter of the front disc 26 less than 90% of the diameter of the composite billet 20 is preferably the metal of the aluminum tubular core billet 22 on the back of the front screen 26 is positioned, an oxide film and impurities on the outer surface of the composite billet 20 are present, and the metal of the Füllmetallknüppels 24 from a gap between the front disk 26 and the container is extruded, resulting in the inclusion of the preferably extruded components to the opposite side portions of the flat tube 10 with multiple openings leads. In addition, the thickness of the front disc is 26 preferably in a range of 5% to 30% of the diameter of the composite billet 20 , and most preferably in a range of 10% to 25%. If the thickness of the front disc 26 less than 5% of the diameter of the composite billet 20 is a portion corresponding to the dead metal remaining in the container, not sufficient with a material of the front pane 26 to be filled, resulting in the inclusion of the filler metal to the opposite side portions of the flat tube 10 with multiple openings leads. On the other hand, if the thickness of the front disc 26 greater than 30% of the diameter of the composite billet 20 is, the ratio of the front wheel 26 with respect to the material of the composite billet excessively high, which raises a problem such as an increase in the amount of the unused metal, which is omitted before the filling metal stably on the outer surface of the flat tube 10 coated with several openings.

The above-described flat extruded multi-port aluminum tube of the present invention is advantageously used in a heat exchanger as a flow channel member for a refrigerant. In the case where the multi-port flat tube according to the present invention is used as a passage tube for the refrigerant, the heat exchanger includes, for example: a pair of spaced apart aluminum equalization tanks; a plurality of flat tubes having a plurality of openings arranged between the two surge tanks at a pitch interval parallel to each other in a longitudinal direction of the surge tanks, their width direction corresponding to the ventilation direction being that the opposite ends of each flat tube having a plurality of openings communicate with the respective surge tanks are connected; Outer ribs in the form of aluminum corrugated fins disposed in the spaces between the adjacent flat tubes having a plurality of openings and at the opposite ends of the array outside the flat tubes having a plurality of openings and being brazed to the flat tubes having a plurality of openings; and aluminum side plates disposed outside of the shaft ribs and connected to the ribs by brazing. The multi-port flat tube according to the present invention may, of course, be used as the passage tube for the refrigerant in various other known heat exchangers than the heat exchanger having the above-described configuration.

As is well known, the refrigerant or a refrigerant in the heat exchanger is distributed from one of the two surge tanks into the flat tubes having a plurality of openings and discharged out of the flat tubes having a plurality of openings so that it flows into the other surge tank. The conventional surge tanks, for example, take the form of a pair of opposed balancing plates brazed to the flat tubes having a plurality of openings; one through Bending a plate formed tube, and welding and brazing end portions of the obtained tube; and an extruded tube.

Although a typical embodiment of the invention has been described in detail for purposes of illustration, it will be understood that the invention is not limited to the details of the foregoing embodiment.

It is understood that the invention can be practiced with various changes, modifications and improvements that will be apparent to those skilled in the art without departing from the spirit and scope of this invention, and that such changes, modifications, and improvements are also within the scope of this invention.

EXAMPLES

To illustrate the invention in more detail, some typical examples of the invention will be described. It is understood, however, that the invention is not limited to the details of the examples.

First, aluminum filler metal billets AR having the respective compositions shown in the following Table 1 and aluminum tube core billets (a) - (o) having respective compositions shown in the following Table 3 were used as materials for producing various ones poured flat tube openings. The resulting billets were composed to produce composite billets B1-B32 shown in the following Table 5, and the composite billets were subjected to hot extrusion so as to obtain respective flat tubes T1-T32 having a plurality of orifices shown in the following table 5 are shown. Similarly, aluminum filler metal billets S-AA having corresponding compositions shown in the following Table 2 and cast aluminum core billets (p) - (u) having the corresponding composition shown in the following Table 4 were cast, and the obtained Billets were combined to produce composite billet B33-B52 and a one-pack billet B53, which are shown in Table 6 below. Subsequently, the composite billets and the one-component billet were subjected to hot extrusion so as to obtain respective flat tubes T33-T53 having a plurality of openings shown in Table 6 below.

The generated flat tubes T1 - T 53 having multiple openings were then evaluated by the following measurements and evaluations: (1) evaluation of a degree of inclusion of a filling metal layer; (2) measuring the length of a defective coating portion; (3) measurement of a formation area of a filler metal portion; and (4) Evaluation of a defect in assembling a core of the heat exchanger. Table 1 Füllmetallknüppelzeichen Chemical composition of the billet (percentage by mass) Si Mn Cr Zr Ti Sr al * A 7.0 0.3 00:15 00:15 00:15 00:05 rest B 4.0 0.3 0.3 - - 00:05 rest C 4.0 0.3 - 0.3 - 00:05 rest D 4.0 0.3 - - 0.3 00:05 rest e 4.0 0.3 00:15 - - 0.1 rest F 4.0 0.3 00:05 - - 00:05 rest G 4.0 0.3 - 00:05 - 00:05 rest H 4.0 0.3 - - 00:05 00:05 rest I 4.0 1.0 00:15 - - 0.0002 rest J 4.0 0.3 00:15 - - 00:05 rest K 4.0 0.3 - 00:15 - 00:05 rest L 4.0 0.3 - - 00:15 00:05 rest M 4.0 0.3 00:15 00:15 - 00:05 rest N 4.0 0.3 00:15 - 00:15 00:05 rest O 4.0 0.3 - 00:15 00:15 00:05 rest P 1.0 0.3 00:15 - - 00:05 rest Q 13.0 0.3 00:15 - - 00:05 rest R 4.0 1.4 00:15 - - 00:05 rest Including unavoidable impurities Table 2 Füllmetallknüppelzeichen Chemical composition of the billet (percentage by mass) Si Mn Cr Zr Ti Sr al * S 00:05 0.7 - - - - rest T 00:05 00:01 - - - - rest U 14.0 0.7 00:15 - - - rest V - 0.7 00:15 - - - rest W 7.0 1.5 00:15 - - - rest X 7.0 0.7 00:35 - - - rest Y 7.0 0.7 00:15 00:35 - - rest Z 7.0 0.7 00:15 - 00:35 - rest AA 7.0 0.7 00:15 - - 0.2 rest Including unavoidable impurities Table 3 Füllmetallknüppelzeichen Chemical composition of the billet (percentage by mass) Cu Mn Cr Zr Ti Sr al * (A) 0.4 0.7 00:15 - - 00:05 rest (B) 0.7 0.4 0.3 - - 00:05 rest (C) 0.2 1.4 - 0.3 - 00:05 rest (D) 0.2 0.4 - - 0.3 00:05 rest (E) 0.2 0.4 00:15 - - 0.1 rest (F) 0.2 0.4 00:05 - - 00:05 rest (G) 0.2 0.4 - 00:05 - 00:05 rest (H) 0.2 0.4 - - 00:05 00:05 rest (I) 0.2 0.4 00:15 - - 0.0002 rest (J) 0.2 0.4 00:15 - - 00:05 rest (K) 0.2 0.4 - 00:15 - 00:05 rest (I) 0.2 0.4 - - 00:15 00:05 rest (M) 0.2 0.4 00:15 00:15 - 00:05 rest (N) 0.2 0.4 00:15 - 00:15 00:05 rest (O) 0.2 0.4 00:15 00:15 00:15 00:05 rest Including unavoidable impurities Table 4 Füllmetallknüppelzeichen Chemical composition of the billet (percentage by mass) Cu Mn Cr Zr Ti Sr al * (P) 0.8 0.7 00:15 - - 00:05 rest (Q) 0.4 1.5 00:15 - - 00:05 rest (R) 0.4 0.7 00:35 - - 00:05 rest (S) 0.4 0.7 00:15 00:35 - 00:05 rest (T) 0.4 0.7 00:15 - 00:35 00:05 rest (U) 0.4 0.7 00:15 - - 0.2 rest Including unavoidable impurities Table 5 Type of composite billet for extrusion Composition of the composite billet front window Type of tube with several openings Füllmetallknüppel Tube core billets Diameter (%) Thickness (%) B1 A (A) 100 10 T1 B2 B (A) 100 10 T2 B3 C (A) 100 10 T3 B4 D (A) 100 10 T4 B5 e (A) 100 10 T5 B6 F (A) 90 10 T6 B7 G (A) 100 5 T7 B8 H (A) 100 30 T8 B9 I (A) 100 10 T9 B10 J (A) 100 10 T10 B11 K (A) 100 10 T11 B12 L (A) 100 10 T12 B13 M (A) 100 10 T13 B14 N (A) 100 10 T14 B15 O (A) 100 10 T15 B16 P (A) 100 10 T16 B17 Q (A) 100 10 T17 B18 R (A) 100 15 T18 B19 A (B) 100 15 T19 B20 A (C) 100 15 T20 B21 A (D) 100 15 T21 B22 A (E) 100 15 T22 B23 A (F) 100 15 T23 B24 A (G) 100 15 T24 B25 A (H) 100 15 T25 B26 A (I) 100 15 T26 B27 A (J) 100 20 T27 B28 A (K) 100 20 T28 B29 A (I) 100 20 T29 B30 A (M) 100 20 T30 B31 A (N) 100 20 T31 B32 A (O) 100 20 T32 Table 6 Type of composite billet for extrusion Composition of the composite billet front window Type of tube with several openings Filling metal billet Tubular core club Throughput r (%) Thickness (%) B33 S (A) 100 10 T33 B34 T (A) 100 10 T34 B35 U (A) 100 10 T35 B36 V (A) 100 10 T36 B37 W (A) 100 10 T37 B38 X (A) 100 10 T38 B39 Y (A) 100 10 T39 B40 Z (A) 100 10 T40 B41 AA (A) 100 10 T41 B42 A (P) 100 10 T42 B43 A (Q) 100 10 T43 B44 A (R) 100 10 T44 B45 A (S) 100 10 T45 B46 A (T) 100 10 T46 B47 A (U) 100 10 T47 B48 A (A) 110 10 T48 (production not possible) B49 A (A) 85 10 T49 B50 A (A) 100 35 T50 B51 A (A) 100 3 T51 B52 A (A) 100 10 T52 B53 - (A) 100 10 T53

More specifically, first, various 90 mm diameter continuously cast billets were produced by a known process in accordance with the chemical compositions formulated to provide the aluminum filler metal billets AR, as shown in Table 1, and the aluminum filler metal billets S - AA described in US Pat Table 2 are shown, around the Aluminiumfüllmetallabschnitt 18 train. On the other hand, various continuously cast billets were similarly made in accordance with the chemical compositions formulated to provide the tube core billets (a) - (o) shown in Table 3 and the tubular billets (p) - (u) shown in Table 4 are shown to form the tube body. The tube core billets thus produced were subjected to molding operations to provide a cylindrical body having predetermined dimensions with a predetermined diameter within a range of 5mm-85mm.

Then, a through-hole into which the tube core billet thus formed can be inserted was formed through a center part in the cross section of each of the above-mentioned aluminum filler metal billets, and the tube core billet was inserted into the through-mold. In addition, the aluminum filler metal billet and the tube core billet were fixed and joined to the opposite longitudinal end surfaces of the billets by MIG welding, so that each of the composite billets B1-B32 and B33-B52 for extrusion shown in Table 5 were made as one-piece composite billets 20 were generated in the 2 has shown cross-sectional shape. The billet B53 for extrusion shown in Table 6 given above is a one-component billet formed solely of the tube core billet, that of the one-component billet 30 that is in the 3 is shown. In the 2 and 3 represent the reference numerals 22 and 32 the tube core billets, and the reference numeral 24 represents the Füllmetallknüppel.

Like from the 2 (c) and Fig. 3), the round-shaped front disk is next 26 having various dimensions shown in Tables 5 and 6 (in which diameter and thickness values are indicated by percent with respect to the diameter of the composite billets) are fixed to the front end face by welding when in the extrusion direction of the composite billet thus obtained 20 or the one-component stick 30 is looked at. Each of the obtained assembled body from the truncheon 20 and the front disc 26 was heated in a stick heater at 500 ° C, and hot extruded from the side of the front disk 26 using a known chamber die having six extrusion bores to form six rectangular holes (six flow passages) such that the flat tubes T1 - T 32 and T 33 - T 53 have a plurality of openings (total thickness of 2.0 mm, width of 16 mm and thicknesses of 0.25 mm of the peripheral wall portion and the inner partition wall portion), as shown in Tables 5 and 6. The multi-hole flat tube T 48 could not be produced because the composite billet B 48 suffered from clogging in the container during hot extrusion and the hot extrusion could not be completed.

Evaluation of the degree of inclusion of a filling metal layer

Each of the sum of the obtained flat tubes ( 10 ) having a plurality of openings having six holes was cut at half the length in the extrusion longitudinal direction and their cross-sectional surface was examined. More specifically, the state of inclusion of the filler metal layer ( 18 ) in the opposite opposite side portions of the cross section of the flat tube ( 10 ) having a plurality of openings for evaluating the degree of inclusion and the use of a photomicrograph at 25X magnification of the cross-sectional area. The results were evaluated as "good" if the filling metal section ( 18 ) was detected in any of the opposite side sections, and as "bad" if the metal section (fig. 18 ) has been detected in at least one of the opposite side portions of the tube.

In the following Tables 7 and 8, the results of the above evaluation of the degree of inclusion of the filler metal portion are ( 18 ) with respect to each of the flat tubes T 1 - T 32 having a plurality of openings and the flat tubes T 33 - T 53 having a plurality of openings. The flat tube T 48 with multiple openings was not evaluated because the hot extrusion was not completed.

As a result of the examination of the cross-sectional area, it was confirmed that any of the flat tubes T 1 to T 32 having a plurality of openings obtained by the extrusion molding do not depend on the inclusion of the filler metal termination (FIG. 18 ) to the opposite side portions of the tube.

Each of the flat tubes T "33", T "34" and T "53" obtained by hot-pressing the respective composite billets B "33" and B "34" and the one-component stick B "53" with the female die was formed of a billet of a known alloy or pure aluminum alloy which was not contained the filler metal component. Thus, none of the tubes T 33, T 34 and T 53 had the filler metal portion ( 18 ) and suffered from the inclusion of the filler metal section ( 18 ) on the opposite side portions of the tubes. Neither of the tubes T 35 - T 47, T 50 and T 52 also suffered from the inclusion of the filling metal section ( 18 ). However, the flat tubes T 49 and T 51 having a plurality of openings had the inclusion of the filler metal portion (FIG. 18 ) on the opposite side portions of the tubes. In each of the tubes T 49 and T 51, the front disk used in their manufacture did not have a sufficient degree of diameter or thickness, whereby an oxide film or impurities on the surface of the aluminum tube core billet positioned on the back side of the disk or the metal of the filler metal billet , for example, preferably flowed in the direction of the width to the opposite side portions of the flat tube with a plurality of openings, which includes the inclusion of the filler metal portion (FIG. 18 ).

Measurement of the length of the faulty coating section

With respect to each of the flat tubes T 1 - T 32 having a plurality of openings and the flat tubes T 33 - T 53 having a plurality of openings obtained as described above, the length of the defective coating portion was measured. It is noted that the flat tubes T 33, T 34 and T 53 were formed with a plurality of openings made of the known alloys or pure aluminum and did not use a billet containing the filler metal component, so that the tubes T 33, T 34 and T 53 the filling metal portion ( 18 ) did not exhibit. The flat tube T 48 with multiple openings was not evaluated because the hot extrusion was not completed, and the tube T 48 could not be produced.

More specifically, each of the flat tubes T 1 - T 32 having a plurality of openings and the flat tubes T 33 - T 53 having multiple openings after hot extrusion were observed in their cross section along the entire length in the extrusion direction with a pitch of 1.0 m, and the length of a defective coating portion was measured. The defective coating portion includes a portion in which only the front disk material was observed and a portion where a coating ratio was too high due to the presence of the front disk material. The results were evaluated as "Good" if the length of the defective coating portion was not more than 15 m, and "Bad" if the length was more than 15 m, and they are shown in Tables 7 and 8 below. Table 7 Type of tube with several openings inclusion evaluation Length of the faulty coating section (m) evaluation T1 Not recognized Good 5 Good T2 Not recognized Good 5 Good T3 Not recognized Good 12 Good T4 Not recognized Good 15 Good T5 Not recognized Good 5 Good T6 Not recognized Good 5 Good T7 Not recognized Good 5 Good T8 Not recognized Good 5 Good T9 Not recognized Good 5 Good T10 Not recognized Good 5 Good T11 Not recognized Good 5 Good T12 Not recognized Good 5 Good T13 Not recognized Good 5 Good T14 Not recognized Good 5 Good T15 Not recognized Good 5 Good T16 Not recognized Good 5 Good T17 Not recognized Good 5 Good T18 Not recognized Good 5 Good T19 Not recognized Good 5 Good T20 Not recognized Good 5 Good T21 Not recognized Good 5 Good T22 Not recognized Good 5 Good T23 Not recognized Good 5 Good T24 Not recognized Good 5 Good T25 Not recognized Good 5 Good T26 Not recognized Good 5 Good T27 Not recognized Good 5 Good T28 Not recognized Good 5 Good T29 Not recognized Good 5 Good T30 Not recognized Good 5 Good T31 Not recognized Good 5 Good T32 Not recognized Good 5 Good Table 8 Type of tube with several openings inclusion evaluation Length of poorly coated section (m) evaluation T33 Not recognized Good 0 Good T34 Not recognized Good 0 Good T35 Not recognized Good 5 Good T36 Not recognized Good 5 Good T37 Not recognized Good 5 Good T38 Not recognized Good 5 Good T39 Not recognized Good 5 Good T40 Not recognized Good 5 Good T41 Not recognized Good 5 Good T42 Not recognized Good 5 Good T43 Not recognized Good 5 Good T44 Not recognized Good 5 Good T45 Not recognized Good 5 Good T46 Not recognized Good 5 Good T47 Not recognized Good 5 Good T48 Extrusion not possible - Extrusion not possible - T49 detected Bad 32 Bad T50 Not recognized Good 25 Bad T51 detected Bad 60 Bad T52 Not recognized Good 5 Good T53 Not recognized Good 0 Good

As apparent from the results shown in Table 7, the length of the defective coating portion in each of the flat tubes T 1 - T 32 having multiple openings was not more than 15 m. Namely, the inclusion of the filling metal layer was effectively suppressed in these tubes.

The flat tubes T 33, T 34 and T 53 were formed from the billets which did not contain the filler metal component, so that these tubes did not have the defective coating portion. The flat tubes T 35 - T 47 and T 52 having multiple openings had the defective coating portions but their lengths not more than 15 m. However, the flat tubes having a plurality of openings T 49 - T 51 had the defective coating portions having a length of more than 15 m. Specifically, the flat tube T 51 having a plurality of openings had the defective coating portion extending along the entire length from the head portion to the dot portion where the extrusion was completed, namely, extended for about 60 m.

Measurement of the area of formation of the sacrificial anode section

Each of the flat tubes ( 10 ) having a plurality of openings having six openings obtained as described above was cut at 1/2 the length point in the extrusion longitudinal direction, and its sectional area was examined. More specifically, the formation areas of the filler metal section ( 18 by measuring with a ruler of a region of the filling metal portion ( 18 ) were evaluated in a photomicrograph with a 25-fold magnification of the cross-sectional area. With reference to the above-mentioned measurement of the area of formation of the filler metal portion (FIG. 18 ) the results were evaluated as "good" if the ratio of the length of the filler metal section ( 18 ) was in a range of 50% to 100% of the tube, and as "bad" if the ratio of the length was less than 50% of the outer circumferential length L the tube was. In addition, with respect to the thickness of the filler metal section ( 18 ) in the outer peripheral wall portion (FIG. 14 ) evaluates the results as "good" if the ratio of the thickness is not higher than 90% of the thickness of the outer peripheral wall portion (FIG. 14 ), and as "bad" if the ratio was higher than 90%.

The following Tables 9 and 10 show the results of the above measurement of the region of formation of the sacrificial anode portion / filler metal portion ( 18 ) with respect to each of the multi-port flat tubes T1-T32 and the multi-port flat tubes T33-T53. The following items are shown in the tables: the ratio of the smallest length of the filler metal portion ( 18 ) exposed in the outer circumference of the tube and the ratio of the largest thickness of the filler metal portion (FIG. 18 ) in the outer peripheral wall portion 14 , Table 9 Type of tube with several openings Condition of formation of the filling metal section Ratio (%) of the smallest total length to the outer circumferential length of the tube evaluation Ratio (%) of the largest thickness t in the peripheral wall portion evaluation T1 80 Good 20 Good T2 100 Good 20 Good T3 80 Good 20 Good T4 60 Good 10 Good T5 50 Good 10 Good T6 100 Good 5 Good T7 100 Good 20 Good T8 100 Good 20 Good T9 100 Good 20 Good T10 100 Good 20 Good T11 100 Good 20 Good T12 100 Good 20 Good T13 100 Good 20 Good T14 100 Good 20 Good T15 100 Good 20 Good T16 90 Good 20 Good T17 90 Good 20 Good T18 90 Good 20 Good T19 90 Good 20 Good T20 90 Good 20 Good T21 80 Good 20 Good T22 90 Good 20 Good T23 90 Good 20 Good T24 90 Good 20 Good T25 80 Good 20 Good T26 80 Good 20 Good T27 80 Good 20 Good T28 80 Good 20 Good T29 80 Good 20 Good T30 80 Good 20 Good T31 80 Good 20 Good T32 80 Good 20 Good Table 10 Kind of multiport tube Type of tube with several openings Ratio (%) of the smallest total length to the outer circumferential length of the tube evaluation Ratio (%) of the largest thickness t in the peripheral wall portion evaluation T33 0 Bad 0 Good T34 0 Bad 0 Good T35 45 Bad 10 Good T36 45 Bad 10 Good T37 45 Bad 10 Good T38 45 Bad 10 Good T39 45 Bad 10 Good T40 45 Bad 10 Good T41 45 Bad 10 Good T42 40 Bad 20 Good T43 40 Bad 20 Good T44 40 Bad 20 Good T45 40 Bad 20 Good T46 30 Bad 20 Good T47 30 Bad 20 Good T48 Extrusion impossible - Extrusion impossible - T49 30 Bad 20 Good T50 30 Bad 20 Good T51 100 Good 93 Bad T52 45 Bad 20 Good T53 0 Bad 0 Good

As a result of examination of the cross-sectional area, it was confirmed that the filler metal portion formed of the filler metal billet (FIG. 18 ) in a ratio within a range of 50% to 100% of the outer circumferential length L of the tube was exposed in the outer circumference of the flat tubes T1-T32 having a plurality of openings obtained by the above-mentioned extrusion molding. With respect to the thickness of the filler metal section ( 18 ), which in the outer peripheral wall portion ( 14 ), the sacrificial anode section / filling metal section (FIG. 18 ) having a thickness of not more than 90% of the thickness of the outer peripheral wall portion (FIG. 14 ) in each of the tubes exposed. In addition, with respect to each of the flat tubes ( 10 ) having a plurality of openings obtained by the hot extrusion described above, it was also confirmed that the filler metal portion (FIG. 18 ) formed from the filler metal billet was stably exposed along the outer surface of the outer circumference of the tube in the longitudinal direction of extrusion molding.

On the other hand, the flat tubes T33, T34 and T53 having a plurality of openings formed by exposing the respective composite billets B33 and B34 of the single-component stick B53 to hot-pressing with the chamber die had an exposed portion of the filler metal portion (FIG. 18 ) on the outer surface of the tube, since the tubes were formed of the known alloys or pure aluminum alloy which did not contain a filler metal component. With respect to the flat tube T51 having a plurality of openings obtained by using the composite billet B51 shown in Table 6, the ratio of the length of the exposed filler metal portion (FIG. 18 ) 100% of the outer circumferential length L of the tube, and the highest ratio of the thickness was 93% of the thickness of the outer peripheral wall portion (FIG. 14 ). Moreover, with respect to each of the flat tubes, T35 - T47, T49, T50 and T52 having a plurality of openings obtained as described above were employed by using the composite billets B35-B47, B49, B50 and B52 described in U.S.P. Table 6, the ratio of the length of the exposed Füllmetallabschnitts ( 18 ) Less than 50% of the length of the outer circumferential length L of the tube, and the highest ratio of the thickness was 10-20% of the thickness of the outer peripheral wall portion (FIG. 14 ). With regard to the flat tube T 48 having a plurality of openings, the composite billet B 48 shown in Table 6 suffered from clogging in the container during hot extrusion, and the desired tube could not be obtained. Thus, the tube T 48 was not evaluated.

X0070x

The evaluation of the degree of error in assembling the core of the heat exchanger

The obtained flat tubes T 1 - T 32 having multiple openings and the flat tubes T 33 - T 53 having multiple openings as samples were assembled with fins and subjected to heating for brazing. Then, the presence or absence of defects in the production of the core of the heat exchanger was evaluated.

More specifically, the multi-port flat tubes T1-T32 and the flat tubes T33-T53 having multiple openings were assembled with bare fins having a thickness of 80 μm, and these bare fins were subjected to a corrugation to give dimensions of a finer pitch of 3 mm and one pitch Have a fin height of 7mm. The flat tubes with multiple openings were subjected to heating at 600 ° C for 3 minutes considering the heating of the tubes due to soldering for joining the fins, where the tube is used as a heat transfer tube for a heat exchanger, thereby forming cores of the heat exchanger , Subsequently, the fins joined to each of the flat tubes having a plurality of openings in the core of the heat exchanger were cut off from the tube with a cutter, and a joining state of the fins and an occurrence of defects in the flat tube having a plurality of openings were measured Eyes examined.

Tables 11 and 12 below show the results of the study. As described above, the examination was made with respect to the joining state of the fins in the core for the heat exchanger and the occurrence of defects in the flat tube having a plurality of openings after heating for brazing. The core was formed of each of the flat tubes T1-T32 and multi-openings and the flat tubes T33-T53 having multiple openings as the samples. Table 11 Type of tube with several openings Lack in the manufacture of the core evaluation T1 Not recognized Good T2 Not recognized Good T3 Not recognized Good T4 Not recognized Good T5 Not recognized Good T6 Not recognized Good T7 Not recognized Good T8 Not recognized Good T9 Not recognized Good T10 Not recognized Good T11 Not recognized Good T12 Not recognized Good T13 Not recognized Good T14 Not recognized Good T15 Not recognized Good T16 Not recognized Good T17 Not recognized Good T18 Not recognized Good T19 Not recognized Good T20 Not recognized Good T21 Not recognized Good T22 Not recognized Good T23 Not recognized Good T24 Not recognized Good T25 Not recognized Good T26 Not recognized Good T27 Not recognized Good T28 Not recognized Good T29 Not recognized Good T30 Not recognized Good T31 Not recognized Good T32 Not recognized Good Table 12 Type of tube with several openings Lack in the manufacture of the core evaluation T33 Fins were not joined Bad T34 Fins were not joined Bad T35 Base material melted Bad T36 Fins were not joined Bad T37 Most fins were not joined Bad T38 Most fins were not joined Bad T39 Most fins were not joined Bad T40 Most fins were not joined Bad T41 Most fins were not joined Bad T42 Most fins were not joined Bad T43 Most fins were not joined Bad T44 Most fins were not joined Bad T45 Most fins were not joined Bad T46 Most fins were not joined Bad T47 Most fins were not joined Bad T48 Extrusion impossible Bad T49 Penetration holes produced in the enclosed portion Bad T50 Most fins were not joined Bad T51 Penetration holes produced in the enclosed portion and the peripheral wall portion Bad There T52 Most fins were not joined Bad T53 Fins were not joined Bad

As is clear from the results shown in Table 11, none of the flat tubes T 1 - T 32 having a plurality of openings suffered from erroneous joining of the fins in the core of the heat exchanger after heating for brazing, or defects were not recognized. The flat tubes T 1 -T 32 having a plurality of openings had a good joining state of the fins and were excellent as the flat tube having a plurality of openings for brazing, owing to the presence of the filling metal portion (FIG. 18 ).

On the other hand, since each of the flat tubes T 33, T 34 and T 53 was formed with multiple openings using only the known material or the pure aluminum alloy not containing the filler metal component, the fins did not become the core of the heat exchanger after heating joined for brazing. Also, in the flat tube T 36 having a plurality of openings of 0% by mass of Si, which is a filler metal component, the fins were not joined. Moreover, the flat tube T 35 having a plurality of openings shown in Table 12 contained 14 mass% Si, namely, it had an excessively large amount of Si, and suffered from melting of the filler metal portion (FIG. 18 ) at the time of heating for brazing, resulting in the formation of penetration holes due to melting in the base material. In addition, in the flat tubes T 37 - T 47, T 50 and T 52 with several openings, some of the fins were joined, but a large number of fins were not joined. In addition, the flat tubes T 49 and T 51 with multiple openings suffered from the creation of penetration holes since the filler metal section (FIG. 18 ) at the time of heating for brazing in the confined portion of the filling metal layer formed in the opposite end corners of the tube. Specifically, in the flat tube T 51 having a plurality of openings, melting in the outer peripheral wall portion (FIG. 14 ) as well as in the enclosed portion of the filling metal layer formed in the opposite side portions of the tube, resulting in the formation of penetration holes due to melting.

LIST OF REFERENCE NUMBERS

10

flat tube with several openings

12

Flow passages

14

Outer peripheral wall sections

16

inner partition sections

18

Füllmetallabschnitt

20

composite billet

22

Tube core billets

24

Füllmetallknüppel

26

front window

30

Einkomponentknüppel

32

Tube core billets

34

front window

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 6504485A [0004, 0006]
• JP 7308795 A [0004, 0006]
• JP 2002172485 A [0004, 0006]
• JP 10258356 A [0005, 0006]
• JP 10197175 A [0005, 0006]
• JP 63097309 A [0006]

Claims (8)

A multi-aperture aluminum tube having a generally flat cross-sectional shape obtained by extruding an aluminum material, the multi-port aluminum tube being an extruded tube having a plurality of flow passages extending independently in an axial direction of the tube, the flow passages in a longitudinal direction of the flat cross-sectional shape are disposed inner partition portions extending along the axial direction of the tube, characterized in that the multi-hole aluminum tube is formed by extrusion molding using as the aluminum material an aluminum tube core material and an Al-Sibasizing aluminum alloy aluminum filler metal Are used, the aluminum filler metal is exposed so that it in an entirety of an outer peripheral wall portion of the tube or in at least part of a flat portion de s outer peripheral wall portion forms filler metal portion, and the filling metal portion provided in the outer peripheral wall portion has a length of 50% to 100% of an outer circumferential length of the outer peripheral wall portion in the cross section of the tube and has a thickness of not more than 90% of a thickness of the peripheral wall portion the aluminum tube with multiple openings has outstanding brazeability. Aluminum tube with multiple openings, which has the outstanding brazeability after Claim 1 wherein the aluminum filler metal comprises an aluminum alloy consisting of 1.0-13.0 mass% Si, at least one selected from the group consisting of not more than 1.4 mass% Mn, 0.05-0.30 mass% Cr , 0.05-0.30 mass% Zr, 0.05-0.30 mass% Ti and 0.0001-0.1 mass% Sr, and the balance being aluminum and unavoidable impurities, and the aluminum tube core material comprises an aluminum alloy which does not more than 0.7 mass% Cu and not more than 1.4 mass% Mn, at least one selected from the group consisting of 0.05-0.30% by mass Cr, 0.05-0.30% by mass Zr, 0.05-0.30% by mass Ti and 0.0001-0.1% by mass Sr and the rest aluminum and unavoidable impurities. Aluminum tube with multiple openings, which has the outstanding brazeability after Claim 1 or 2 wherein the aluminum material to be extruded is a composite billet consisting of the aluminum tubing core material and the aluminum filler metal. Aluminum tube with multiple openings, which has the outstanding brazeability after Claim 3 wherein the composite billet has a one-piece shell core structure consisting of a core billet formed of the aluminum core material and a shell billet formed of the aluminum fill metal, the shell billet being arranged to surround the core billet. Aluminum tube with multiple openings, which has the outstanding brazeability, after one of Claims 1 to 4 wherein the extruded tube is formed by extruding the aluminum material and using a chamber tool. A method of producing the multi-aperture aluminum tube having the superior brazeability according to any one of Claims 1 to 5 method comprising the steps of providing a composite billet consisting of the aluminum tube core material and the aluminum fill metal of the Al-Si based aluminum alloy and a front disk formed of the same material as the aluminum tubular core material and the front disk is configured to have a diameter of 90 % to 100% of a diameter of the composite billet, and have a thickness of 5% to 30% of the diameter of the composite billet; Providing the front disk at a front side of the composite billet in an extrusion direction; and coextruding the front disk and the composite billet with a chamber tool to obtain the multi-port pipe. A method of producing the multi-port aluminum tube that has the superior brazeability Claim 6 wherein the composite billet has a one-piece shell core structure consisting of a core billet formed of the aluminum tubular core material and a shell billet formed of the aluminum fill metal, the shell billet being arranged to surround the core billet. Aluminum heat exchanger with aluminum tube with several openings after one of Claims 1 to 5 and aluminum outer fins brazed to an outer surface of the multi-port aluminum tube.

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