JP6204247B2 - Method for producing aluminum clad material - Google Patents

Description

  The present invention relates to a method for producing an aluminum clad material, and in particular, an Al core material made of aluminum or an aluminum alloy is laminated and laminated on one or both sides of an Al core material made of aluminum or an aluminum alloy, and the obtained laminate The present invention relates to a method of advantageously producing an aluminum clad material in which an Al core material and an Al skin material are joined and integrated by hot rolling.

  Aluminum clad material is laminated in a form in which Al core material is laminated on one side or both sides of Al core material, or Al intermediate material made of aluminum or aluminum alloy is interposed between the core material and skin material depending on the application. A multilayer structure (laminate), and such a laminate is heated to a predetermined temperature, hot-rolled, and then cold-rolled to a predetermined thickness. It is the obtained board | plate material. Various types of manufacturing methods have been proposed for this type of aluminum clad material (see, for example, Patent Documents 1 to 3), and actually, in heat exchangers for transportation equipment such as aircraft and automobiles. Although it has been used as a brazing sheet, many problems to be solved still remain in the conventional method for producing an aluminum clad material.

  Specifically, the bonding at the interface of the laminate subjected to the above hot clad rolling is generally referred to as pressure welding, which means that bonding is performed by applying a strong pressure at a high temperature. In that case, since the surface of each laminated material, such as Al core material and Al skin material, is covered with the oxide film, it is necessary to destroy the oxide film for joining them. Thus, by applying a strong pressure in the direction perpendicular to the joining surface by hot clad rolling, the oxide film cannot be destroyed and is difficult to join. It is generally recognized that it is necessary to break the oxide film by sliding the interface of these laminates.

Actually, in a clad material having a high clad rate of the skin material, sliding hardly occurs at the interface between the core material and the skin material, and it is difficult to join them. On the other hand, in the case of a clad material having a low clad rate, the temperature of the skin material is lowered before hot clad rolling, and the oxide film is not easily destroyed. There is a problem that a rolling failure is likely to occur due to tearing or the like. For this reason, it is the actual situation that the clad rate of the aluminum clad material is generally limited to a range of 5 to 25% due to such manufacturing problems. Furthermore, JIS-named 5000 series, 6000 series, and 7000 series Al alloys containing a large amount of magnesium (Mg) have Mg oxide (MgO) on the surface in addition to aluminum oxide (Al ₂ O ₃ ). Since it is formed and the oxide film becomes strong, it is considered difficult to produce a clad material using such an aluminum core material or skin material.

  By the way, as described above, sliding at the interface during clad rolling is generally understood to be beneficial in destroying the oxide film, but as an adverse effect caused by such sliding, The cladding ratio distribution can be deteriorated. That is, the sliding of the interface is caused by the difference in elongation between the Al core material and the Al skin material during rolling, but in the rolling of the clad material, the portion closer to the rolling roll tends to stretch in the rolling direction. Therefore, when the strength of the core material is the same as that of the skin material, or the strength of the skin material is lower than the strength of the core material, the elongation of the skin material becomes remarkable compared to the core material, and conversely, the strength of the core material is the strength of the skin material. If it is lower than that, the elongation of the core material may become remarkable as compared with the skin material. In any of these cases, after the interface between the Al core material and the Al skin material is sufficiently joined, the core material and the skin material will be stretched uniformly. At the initial stage, many factors such as the material of the core material and the skin material, the cladding rate, and the transition of the rolling temperature and reduction (rolling rate) affect the difference in elongation. For this reason, it is difficult to accurately predict the difference in elongation between the core material and the skin material until the interface is sufficiently bonded, and this causes a decrease in the accuracy of the cladding rate. It is.

  On the other hand, since the sliding at the interface becomes prominent at the front and rear end portions in the rolling direction where the portion that becomes the sliding resistance decreases and the left and right end portions in the width direction, the front and rear end portions and the width direction in the rolling direction At the left and right end portions, there will be a difference in the cladding ratio compared to the central portion.For example, when the skin material extends compared to the core material, the cladding ratio at the front and rear end portions and the left and right end portions will decrease. is there. For this reason, in a hot-rolled clad material, the front and rear end portions and the left and right end portions where the clad rate is outside the allowable range are generally cut and removed, which significantly reduces the yield of the clad rolled material. This is a factor that greatly increases the cost of the clad material.

  Further, the reason for the difference in the clad rate at different parts of the aluminum clad material, in other words, the variation in the clad rate distribution is considered as follows. First, in the production of an aluminum clad material, in the initial stage of hot clad rolling, it is generally carried out with a low reduction rate of several percent or less, but the aim is to first stretch the Al skin material. (If the strength of the skin material is higher than the strength of the core material, flatten it) and make it contact with the Al core material or the Al intermediate material uniformly in a plane, and secondly, the Al core material and the Al skin material should not be contacted. It is to be joined in a plane shape even though it is complete. In particular, when the hot rolled material is used as it is for the Al skin material, if the flatness of the skin material is poor, the initial number of passes in the hot clad rolling for the production of the clad material is determined as follows. Without being joined to the skin, it is applied only to stretching or flattening of the skin material. Further, even when the bonding interface of the skin material is machined to improve its flatness, only the skin material or the core material may extend substantially in the initial few passes. At this time, for example, when only the skin material is stretched, first, the clad rate in the entire clad material is decreased, and the degree of the decrease in the clad rate becomes more conspicuous at the end portion where the resistance of the skin material is small as described above. It is.

  Then, in the next stage where the bonding at the interface has progressed to some extent, the rolling reduction rate is slightly increased, the Al core material and the Al skin material are greatly stretched by a strong rolling force, and a strong frictional force is generated at the bonding interface, thereby oxidizing. Although the film is broken so that it is fully bonded, complete bonding of the interface does not occur uniformly at the same time across the interface. In the region where the bonding is insufficient, for example, when the strength of the skin material is lower than the strength of the core material, the thickness reduction of the skin material by the extension of the skin material preferentially proceeds rather than the decrease in the thickness direction of the core material, The cladding rate partially decreases. Since this partial decrease in the cladding rate occurs at portions other than the front and rear ends and the left and right ends of the cladding material, even within the product surface that is not subject to cutting, the cladding rate varies unevenly. Will occur.

  Thus, due to the difference in strength between the Al core material and the Al skin material with respect to the target clad rate, the accuracy of the entire clad material is distorted. The clad rate is greatly changed, and even within the product surface that is not the object of excision, the clad rate varies unevenly.

JP 2002167676 A JP 2008-264825 A JP 2013-220435 A

  Here, the present invention has been made in the background of such circumstances, and the problem to be solved is to greatly improve the clad rate distribution of the aluminum clad material and to significantly improve the product yield. Another object of the present invention is to provide a method for producing an aluminum clad material that can greatly relax the restrictions on the material and clad rate of the laminated material to be clad.

  In the present invention, in order to solve such a problem, the Al core material made of aluminum or aluminum alloy is laminated and laminated on one side or both sides of the Al core material made of aluminum or aluminum alloy. When the aluminum clad material formed by joining and integrating the Al core material and the Al skin material by hot rolling the laminate, the aluminum wire made of aluminum or aluminum alloy is used as the vertical and horizontal lines. The thickness formed by intersecting the vertical lines and the horizontal lines obtained by intersecting them in a grid pattern is a point-like thick portion of 0.2 to 3.2 mm in two vertical and horizontal directions. In this case, the dotted thick member having a structure arranged at an interval of 0.2 to 13 mm is used as a bonding boundary between the Al core material and the Al skin material While interposing them in the laminate, the Al core material, the punctiform thick member, and the Al skin material are fixed or partially fixed at the outer peripheral portion of the joint interface. The gist of the present invention is a method for producing an aluminum clad material, characterized in that the laminate is hot-rolled in a state where it is communicated with the atmosphere.

  In addition, according to one of the preferable aspects of the manufacturing method of the aluminum clad material according to this invention, the said Al wire has a wire diameter of 0.1-1.6 mm.

  According to another preferred embodiment of the method for producing an aluminum clad material according to the present invention, the Al wire is formed of an Al-Mg alloy containing 1.5 to 6% by mass of magnesium. Yes.

  Further, in the present invention, advantageously, the Al wire material constituting the dotted thick member has its surface oxide film chemically broken and removed by treatment with an acid solution or an alkali solution. Yes.

  In addition, in the method for producing an aluminum clad material according to the present invention, advantageously, the hot rolling is performed by passing the laminate a plurality of times between a pair of rolling rolls, and the odd number of times. In this pass and the even-numbered pass, the rotation directions of the rolling rolls are opposite to each other, and reverse rolling is performed in which the rolling directions are alternately opposite to each other.

  In addition, according to one of the desirable embodiments of the present invention, after the laminate is inserted between a pair of rolling rolls in an unloaded state, the laminate is loaded, and then the rolling roll is rotated. By causing the rolling to proceed, the reverse rolling is performed such that the hot rolling proceeds and the rolling rolls rotate in opposite directions each time the rolling roll is passed.

  According to another desirable aspect of the method for producing an aluminum clad material according to the present invention, a plate-like Al intermediate material made of aluminum or an aluminum alloy is further provided between the Al core material and the Al skin material. The point-like thick member is disposed between the Al core material and the Al intermediate material and between at least one of the Al intermediate material and the Al skin material. The laminate is configured with the Al core material, the Al intermediate material, the point-like thick member, and the Al skin material partially fixed or not fixed at the outer peripheral portion thereof.

  According to such a method for producing an aluminum clad material according to the present invention, compared to a hot rolling process in the production of a conventional aluminum clad material, first, a large number of point-like thicknesses distributed at predetermined intervals in a point-like thick member. Depending on the meat part, the Al core material and the Al skin material (when an Al intermediate material exists between them, the core material and the intermediate material and / or the combination of the intermediate material and the skin material are included. The same applies hereinafter) As a result, the quality of the resulting aluminum clad material is improved in several ways by the fact that the Al core material and the Al skin material located on both sides of the point-like thick member are rolled without sliding against each other. Will be.

  That is, first, since the Al core material and the Al skin material do not slide with each other, the core material and the skin material are stretched together, so that the cladding ratio distribution can be greatly improved. In addition, since the progress of the joint is uniformly expanded starting from the point-like thick parts dispersed at the joint interface, the conventional hot rolling process often causes problems such as blistering (due to wide unjoined areas). Peeling and local swelling of the skin material) hardly occur.

  In addition, the present invention is further superior in that an aluminum clad material having a clad rate that was difficult to adopt and an aluminum material that was difficult to produce in the conventional hot clad rolling process can be produced. That is. That is, even when the Mg content of the laminated material to be clad is large, the oxide film is destroyed by the strong rolling force applied to the spot-like thick part, and the shearing force generated at the boundary between the spot-like thick part and the others As a result, the destruction of the oxide film progresses, and as a result, the joining region expands starting from the point-like thick part, so that a laminate material with a high Mg content can be easily clad rolled. It became. In addition, even when the cladding ratio is high or low, the same bonding process can be reproduced. Therefore, according to the present invention, restrictions on the cladding ratio can be substantially eliminated. It will be.

  As described above, by adopting the method for producing an aluminum clad material according to the present invention, the production yield of the aluminum clad material can be greatly improved, and not only a significant cost reduction is brought about, but also a material that has been difficult to produce in the past. It was possible to manufacture a high-difficult aluminum clad material having a cladding ratio and a high quality, and there is a great feature there.

  First, according to the present invention, a predetermined Al wire made of aluminum or aluminum alloy is crossed in a grid pattern in two vertical and horizontal directions, and the point-like thick portions formed at the intersecting portions are predetermined in two vertical and horizontal directions. By substantially fixing the Al skin material and the Al core material or the Al intermediate material, or the Al core material and the Al intermediate material, through the point-like thick members that are distributed apart from each other, the joint interface is substantially obtained. It has a great feature in that it can be joined with almost no sliding. That is, due to the presence of such a point-like thick member, it is very strong against the thick-walled portion distributed in the form of dots at the initial stage of hot rolling for cladding, particularly at the stage of causing sliding at the joint interface. For example, in the case where the Al core material and the Al skin material are clad, the Al core material and the Al skin material are fixed in a dotted shape, when the Al core material and the Al skin material are clad. As a result, the sliding of the joining interface hardly occurs.

  On the other hand, a member having a structure that does not have a point-like thick portion between the Al core material to be joined and the Al skin material, such as a punching metal of an aluminum plate (a circular or rectangular hole in a mesh shape) When a member such as an open plate member is interposed, the reduction force is uniformly received by the entire member (punching metal), so that the joining of the Al core material and the Al skin material via the member is performed. In many cases, the Al skin material or the Al core material is stretched in the same manner as when such a member is not interposed.

  Then, as described above, in the next clad rolling stage in which the Al core material and the Al skin material are fixed in a dot shape via the dotted thick part, the Al core material and the Al skin material connect the dotted thick part. As a result, the Al core material and the Al skin material are fixed in a cell shape. In the progress stage in which the Al core material and the Al skin material are fixed in a dot shape and a cell shape with the dotted thick member interposed, the Al core material and the Al skin material are slightly deformed in the cell. At this time, in the part in contact with the Al wire part connecting the pointed thick part and the adjacent part in the pointed thick member, each of the pointed thick member, the Al skin material, and the Al core material is oxidized by a strong frictional force. When the coating is destroyed, the Al core material and the Al skin material are joined to the point-like thick member, and the Al core material and the Al skin material that are slightly deformed in the cell are joined to the point-like thick member. Since the breakdown of the oxide film starts from the part, the joining of the Al core material and the Al skin material that are in contact with each other in the cell with the progress of rolling is facilitated.

  In such a process of joining, the point-like thick parts need to be held in a fixed manner in two vertical and horizontal directions. If this point-like thick part is isolated and its position is not constrained or fixed, the point-like thick part isolated by a strong reduction force is temporarily combined with Al skin material, Al core material or Al intermediate material. This is because even in the next rolling pass, the joint portion of the dotted thick portion is easily broken by the shearing force generated by the expansion of the Al skin material or the Al core material. As a result, the effect of the present invention cannot be fully exerted by the fact that sliding occurs at the joint interface substantially in the same manner as in the state where the point-like thick portion does not exist. In addition, the fixed holding by the Al wire in the vertical and horizontal two directions of the point-like thick part is basically realized by positioning the Al wire in the rolling direction and the direction orthogonal to the rolling direction. Even if it is realized by an Al wire disposed in a direction rotated by 45 °, the same effect can be exhibited.

  By the way, as the thickness of the dotted thick portion in such a dotted thick member, among the materials to be laminated, an appropriate thickness according to the thickness at the time of laminating the Al skin material or Al intermediate material in particular. However, regardless of the thickness when the Al skin material or Al intermediate material is laminated, when the thickness of the dotted thick part is less than 0.2 mm, the dotted thick part As the joint strength of the clad is reduced, it is difficult to achieve the desired effect, and if the thickness exceeds 3.2 mm, the smoothness of the surface of the resulting clad material will be adversely affected. is there. For this reason, in this invention, the thickness in the range of 0.2 mm-3.2 mm will be selected as thickness of the dotted | punctate thick part in a dotted | punctate thick member.

  In addition, the distance between the point-like thick parts in the point-like thick member is determined in accordance with the thickness at the time of lamination of the Al skin material among the materials to be laminated. However, regardless of the thickness at the time of lamination of such Al skin material, when the distance between the dotted thick parts is less than 0.2 mm, the rolling force to the dotted thick parts becomes weak, This is not preferable because the bonding strength of the thick portion is reduced. On the other hand, when the distance between the dotted thick parts exceeds 13 mm, the shearing force in the rolling direction at the joints of the dotted thick parts becomes strong, and it becomes easy to break, and the sliding of the laminated material This is not preferable because the effect of preventing the deterioration becomes poor. For this reason, in this invention, the distance between dotted | punctate thick parts will be in the range of 0.2 mm-13 mm.

  And in this invention, the dotted | punctate thick member which has such a dotted | punctate thick part uses the Al wire which consists of aluminum or aluminum alloy as a vertical line and a horizontal line, and these cross | intersect a grid pattern form. The above-mentioned dotted thick part is formed at the intersection of the vertical line and the horizontal line, and the dotted thick part is further formed in the vertical and horizontal directions. It exhibits a structure that is arranged at predetermined intervals in two directions. When the wire diameter of the Al wire used here is less than 0.1 mm, the thickness of the dotted thick part formed is less than 0.2 mm, and the bonding strength of the dotted thick part decreases as described above. In addition, it becomes difficult to achieve the intended effect, and when the wire diameter of the Al wire exceeds 1.6 mm, the thickness of the dotted thick part exceeds 3.2 mm. As described above, the smoothness of the clad material is adversely affected. For this reason, the wire diameter of the Al wire is selected in the range of 0.1 mm to 1.6 mm. Moreover, as a specific configuration of the dotted thick member configured by using such Al wires as vertical lines and horizontal lines, for example, the shape is fixed by alternately changing the vertical relationship of the Al wires arranged vertically and horizontally. In a state where a large number of point-like thick parts, such as those obtained by joining the intersections of Al wires arranged vertically and horizontally by pressure bonding or the like, are constrained or fixed so that their arrangement positions do not change freely. Although it can mention the structure of being distributed at predetermined intervals in the vertical direction and the horizontal direction, practically, a woven wire mesh such as a plain woven wire mesh or a twill woven wire mesh using an aluminum wire or an aluminum alloy wire is used. Will be.

  By the way, when clad rolling a material made of a material having poor bondability, a technique is known in which the bond interface is decompressed to improve the bondability [for example, Ying, Nishio, Kato, Inoue, Hatanaka: Welding Society Ninth volume (1991) No. 1], by adopting such a technique, even in a clad material intended for an aluminum material, depending on the laminated material structure, an effect of improving the bonding property may be obtained. Although it is conceivable that it can be used, if the method of reducing the pressure of the entire rolling line proposed for reducing the pressure at the joining interface is adopted, the equipment cost becomes very high and the cost of the clad material is high. Therefore, it is difficult to adopt industrially. Further, in order to reduce the cost of such a decompression method, the periphery of the joint interface, in other words, the outer peripheral portion of the laminate of the material to be clad is formed over the entire periphery in the form leaving one exhaust port. After welding, it is considered that the joint interface is depressurized from the exhaust port and sealed, but not only is it troublesome to weld, exhaust and seal, but also in the production of aluminum clad material. In the initial stage of hot rolling, cracks are likely to occur in the surrounding welds, and external air flows into the joint interface from such cracks, which causes local peeling or blistering. It is. In particular, by interposing a material such as the point-like thick member according to the present invention in such a joint interface, and reducing the pressure of the joint interface, the inflow of outside air from the weld crack is more likely to occur, The inflowing air hinders the expansion of the joining region starting from the point-like thick part, and further increases the risk of blistering and the like.

  Therefore, in the present invention, while a predetermined point-like thick member is interposed at the bonding interface between the Al core material and the Al skin material to be clad-bonded, while the bonding interface is in communication with the atmosphere, Accordingly, one feature is that clad rolling is performed without reducing the pressure at the bonding interface. The air existing at the bonding interface before the clad rolling is gradually discharged as the gap between the bonding materials is reduced and the bonding area is expanded, and finally, the Al thick wire connecting the point-like thick part is connected to it. A small amount of air remains in the cell formed in the part, but the remaining air is in a small amount and is dispersed at the interface in each cell, causing peeling and blistering. It is not a factor.

  In short, the first function of the spot-like thick member used in the method for producing an aluminum clad material according to the present invention is to suppress sliding at the joining interface between the Al core material and the Al skin material to be joined. The second function is to destroy the oxide film of the Al core material and the Al skin material to promote interfacial bonding. On the other hand, since the point-like thick member itself is deformed by the rolling force during the clad rolling, the oxide film covering the surface of the Al wire constituting the point-like thick member is caused by such deformation. The present invention also has a third function of breaking and improving the bondability with the Al core material and the Al skin material. In order to fulfill the above first and second functions, it is desirable that the strength of the Al wire material constituting the point-like thick member is equal to or higher than that of the Al core material or the Al skin material. With regard to, the strength of the Al wire is more likely to be exhibited when it is equal to or less than that of the Al core material or Al skin material. As described above, the strength of the Al wire is not limited to a specific range, but in order to improve the cladding ratio distribution, it is necessary to suppress the sliding of the bonding interface. It is effective to raise. In that case, since hot clad rolling is generally performed at a temperature of about 450 to 500 ° C., the strength at a temperature of about 450 to 500 ° C. is required for the Al wire. .

  And, Mg is the most effective additive element (alloy component) that enhances the high-temperature strength of the Al wire. Therefore, in the present invention, 1.5 to 6% by mass of Mg is contained in aluminum. Thus, an Al wire material made of an Al—Mg alloy is preferably used. In addition, when this Mg content is less than 1.5% by mass, the effect of improving the strength is poor. On the other hand, when the Mg content exceeds 6% by mass, there is a problem that the production of the wire becomes difficult. In addition, examples of strength improving elements other than Mg include Si, Cu, Mn, and Zn. It is also effective to add and contain at least one of these elements together with Mg. Furthermore, in the present invention, it is also effective to make the Mg content in the Al wire more than the Mg content in the aluminum or aluminum alloy constituting the Al core material or Al skin material.

  On the other hand, in order to further improve the third function of the point-like thick member (Al wire), that is, the function of joining the Al core material and the Al skin material through the Al wire material, the interface between the core material and the skin material is required. It is effective to chemically destroy and remove the oxide film on the surface of the Al wire constituting the dotted thick member to be loaded with an acid solution or an alkali solution. The destruction and removal of the oxide film by this acid or alkali is generally called an etching process, but in the etching process of the Al wire material in the present invention, as in the prior art, hydrofluoric acid, sulfuric acid, phosphoric acid, water An aqueous solution of acid or alkali such as sodium oxide or potassium hydroxide is typically used, and nitric acid or the like is also used for removing smut generated by etching. By this etching process, a natural oxide film is immediately formed on the surface of the aluminum wire from which the oxide film has been destroyed and removed, after such etching process. Compared to Al wire that has not been etched, it is possible to improve the bondability with Al core material and Al skin material because it is thinner and more brittle and is easily broken by the rolling force during clad rolling. It becomes.

  In the present invention, the above-described point-like thick member is used, and this point-like thick member is made of a laminate obtained by laminating and laminating Al skin material on one side or both sides of an Al core material. It is interposed in the overlapping surface, in other words, it is interposed in the bonding interface between the Al core material and the Al skin material, and further, as described above, the core material and the core material are connected so as to be in communication with the atmosphere. The hot clad rolling is performed after or without fixing the point-like thick member and the skin material partially at the outer peripheral portion thereof. The elongation of the Al skin material or the Al core material in the rolling direction at the time of the clad rolling always occurs toward the rear side with respect to the traveling direction of the rolling, but the core material and the point-like thick member in the laminate described above In the case where partial fixing to the outer peripheral portion of the skin material is employed, such fixing is performed by applying partial fixing to the outer peripheral portions (side portions) at both ends in the rolling direction of the laminate. It is desirable to be implemented.

  By the way, generally, welding is advantageously employed as a means for partially fixing the Al core material, the point-like thick member, and the Al skin material constituting such a laminate at the outer peripheral portion thereof. However, the present invention is not limited to this, and a fixing (joining) method by brazing or FSW (friction stir welding), a fastening method by an aluminum metal fitting, or the like can be appropriately employed. In addition, such partial fixation in the outer peripheral portion is such that the Al core material, the dotted thick member, and the Al skin material are interposed in a state where the dotted thick member is interposed at the interface between the Al core material and the Al skin material. This is performed on a part of the outer peripheral part including at least a part where the peripheral part of the joining interface is located, and thereby the joining interface is communicated with the outside atmosphere except for the fixing part. It is in the form. Further, such partial fixing in the outer peripheral portion is similarly performed even when a predetermined Al intermediate material is interposed between the Al core material and the Al skin material. Applied to intermediate materials and between Al intermediate materials, point-like thick-walled members, and Al skin materials, and clad rolling is performed in a form in which each interface is connected to the outside atmosphere. It has come to be.

  In the present invention, instead of the partial fixing in the laminate as described above, the Al core material, the dotted thick member, and the Al skin material (or the Al core material, the dotted thick wall) constituting the laminate. The laminate is subjected to clad rolling in a form in which the joining interface is communicated to the atmosphere without fixing the member and the Al intermediate material or the Al intermediate material, the point-like thick member, and the Al skin material) to each other. It is also possible. However, when the laminated materials constituting the laminate are in a disjointed state, problems arise in handling in the heating process or the like. For example, heating is performed in a form in which the laminate is fixed with an appropriate fastening band. It is also possible to remove the fastening band immediately before the clad rolling and set the roll in an unfixed state to start the clad rolling.

  Further, as described above, the elongation of the Al skin material or the Al core material can be advantageously suppressed by the presence of the point-like thick member. However, when the clad rolling is performed only in one direction, the skin material or the core material. Are always stretched in the same direction, and depending on the material strength and material configuration, it may be difficult to exert the effect of suppressing the stretching. For this reason, when the clad rolling is performed by passing the laminate a plurality of times between the rolling rolls, the rotation directions of the rolling rolls in the odd-numbered pass and the even-numbered pass are opposite to each other. It is desirable to carry out the reverse rolling in which the rolling directions are alternately reversed. That is, for each clad rolling pass, the rolling direction of the rolling roll is reversed, and the rolling direction of the rolling roll in the odd-numbered and even-numbered passes is reversed so that the rolling proceeds in both directions. It becomes effective. In this way, rolling is performed at the portion where the Al core material and the point-like thick member are in contact with each other, and the portion where the point-like thick member and the Al skin material are in contact with each other by advancing the clad rolling while being reversed in both the front and rear directions. Since one end side portion and the other end side portion in the direction are joined by receiving a strong reduction force, peeling of the joined portion hardly occurs.

  Furthermore, in the present invention, the laminate obtained by laminating the Al core material, the point-like thick member, and the Al skin material is inserted between the pair of upper and lower rolling rolls in an unloaded state, and then the lamination is performed. Reverse rolling is performed by applying a load to the product and then rotating the rolling roll to advance the clad rolling, and each time the laminate passes the rolling roll, the rotating direction of the rolling roll is opposite to each other. As a result, the effect of suppressing the expansion of the skin material or the core material can be more advantageously exhibited as compared with the case where a rolling force is applied during insertion between the rolls. In the first pass of the clad rolling, since the Al core material, the point-like thick member, and the Al skin material are not joined at all, when the rolling force acts upon the first insertion between the rolls, the Al skin material or The Al core material will be freely stretched in the state of no resistance on the rear side with respect to the rolling direction, but as described above, rolling is performed from a state in which a load is applied to the rolling target material (laminate). By starting, it is possible to improve the adhesion between the point-like thick member near the rolling roll, the Al core material, and the Al skin material before the expansion of the Al skin material or the Al core material. Alternatively, free stretching of the Al core material can be effectively suppressed. At that time, the initial load on the laminate can be set by setting the roll gap, but it is desirable to carry out the load control in order to improve the adhesion with high accuracy. In addition, the position where the load is first applied to the laminate may be any position in the longitudinal direction (rolling direction) of the laminate, and in order to further improve the adhesion, particularly in the initial stage of rolling. Bidirectional rolling by control may be repeated and performed.

  By the way, the Al core material and the Al skin material which give the aluminum clad material manufactured according to the present invention are both plate-shaped materials made of known aluminum or aluminum alloy, for example, 1000 series aluminum of JIS name. In addition, various aluminum alloys of 2000 series to 8000 series are used as the material thereof. In particular, in the present invention, JIS designation 5000 series and 6000, which have conventionally been difficult to produce clad materials. It is possible to manufacture a clad material using a core material or a skin material made of a 7000 series aluminum alloy. Also, aluminum or aluminum alloy adopted as the material of the core material or skin material is appropriately selected according to the use of the aluminum clad material to be produced, and for example, a brazing sheet used for a heat exchanger or the like In this case, an Al skin composed of a brazing material made of an Al—Si based aluminum alloy is used, and this is clad rolled in combination with an Al core material made of an Al—Mn based aluminum alloy or the like. It becomes.

  Further, when the aluminum clad material is manufactured according to the present invention, the form of the Al core material or Al skin material constituting the laminate subjected to hot clad rolling is generally a plate of a predetermined thickness made of aluminum or an aluminum alloy. For example, as an Al core material, an aluminum slab (thick plate block) made of aluminum or an aluminum alloy is subjected to a process such as chamfering to obtain a predetermined thickness. In the case of the material, the plate material obtained by hot rolling the aluminum slab is used. In addition, when the flatness of the plate material for the hot-rolled skin material is poor, by increasing the point-like thick part of the point-like thick member interposed at the joining interface within a predetermined range, In addition to exhibiting a clear effect, if the joint interface of the hot-rolled sheet material for the skin material is smoothed by machining, the point-like thick part in the point-like thick member is within a predetermined range. It is also possible to make it thinner.

  Furthermore, as another form of the Al skin material used in the present invention, it is formed of a thick plate cut out from an aluminum slab, and its joining interface is smoothed by machining, It can be used as a skin material.

  And, in common to such Al skin material and Al core material, in addition to machining, it is also possible to adopt a method of artificially providing unevenness by brushing with a metal brush in addition to machining. Further, if possible on the equipment, it is also possible to perform the etching process in the same manner as the point-like thick member (Al wire). In any case, the surface oxide film of the Al core material or the Al skin material is destroyed by processing before rolling or artificially provided with unevenness to increase the sliding resistance. It is effective in exhibiting.

  In the present invention, hot clad rolling is performed using a laminate in which a point-like thick member is interposed between the Al core material and the Al skin material. The present invention can also be applied to a laminate in which a plate-like Al intermediate material made of aluminum or an aluminum alloy is interposed between the materials. For example, in an aluminum clad material for a heat exchanger, a plate-like Al intermediate material made of an Al—Zn-based aluminum alloy that provides a sacrificial anode layer is interposed between an Al core material and an Al skin material for the purpose of improving corrosion resistance. The present invention is advantageously applied to the aluminum clad material having such a structure. And in such an aluminum clad material composed of Al core material, Al intermediate material, and Al skin material, at least one of the interface between the core material and the intermediate material and the interface between the intermediate material and the skin material. The effect according to the present invention can be advantageously exhibited by interposing the point-like thick member according to the present invention and hot-clad rolling.

  As described above, the method for producing the aluminum clad material according to the present invention has been specifically described in detail. However, the present invention is not to be construed as being limited in any way by the detailed description of the specific embodiment. Based on the knowledge of those skilled in the art, the present invention can be implemented in a mode with various changes, modifications, improvements, etc., and any such mode can be used without departing from the gist of the present invention. It should be understood that it belongs to the category of the present invention.

  Hereinafter, some examples of the present invention will be shown and the present invention will be more specifically clarified. However, the present invention is not limited by the description of such examples. It should also be understood that there is nothing.

Example 1
First, an Al skin material (wax material), an Al intermediate material, and an Al core material made of various chemical components shown in Table 1 below were prepared. That is, for the Al core material, an Al ingot (slab) formed by continuous casting was prepared in the same manner as before in a thickness of 120 to 198 mm × width: 200 mm × length: 300 mm. In addition, each of the Al skin material (brazing material) and the Al intermediate material is cast according to an ordinary method and then hot-rolled to a predetermined thickness, and then width: 200 mm × length: 300 mm It was manufactured by cutting to the following dimensions.

  Moreover, as a point-like thick member interposed between the Al core material and the Al skin material, an Al wire material having a wire diameter of 0.07 mm to 1.9 mm is used as a vertical line and a horizontal line, in a plain weave structure. Various plain woven wire meshes crossed vertically and horizontally were used. In addition, the material of the Al wire material includes an Al—Mg alloy having a Mg content of 1,1.5, 2.5, 4, or 6 mass%, or an Al Mg content of 1.2 mass%. -Mn alloy is employed, and the thickness of the dotted thick part is 0.14 mm to 3.8 mm depending on the wire diameter of the Al wire, and the vertical and horizontal intervals of the dotted thick part are 0. What prepared 14 mm-16 mm was prepared.

  Furthermore, the surface treatment of each material, in other words, for the Al core material and the Al skin material, the treatment of the joint interface, and the surface treatment of the dotted thick member (plain woven wire mesh) were performed as follows. . First, about a part of Al core material which has the joint surface by which surface machining was carried out by machining, the uneven | corrugated process was given with the wire brush with respect to the joint surface which carried out the chamfering. Moreover, the joining surface of the Al skin material is hot-rolled (however, degreasing with acetone is performed), and any one of alkaline etching with 5% aqueous sodium hydroxide and unevenness with a wire brush is performed. Carried out. Furthermore, the point-like thick member was subjected only to degreasing with acetone or acid etching treatment with 1% hydrofluoric acid aqueous solution.

  Next, the above-described various Al core materials, Al intermediate materials, Al skin materials, and point-like thick members having dimensions of 200 m × 300 mm were laminated in the combinations shown in Tables 2 to 4 below, and the obtained laminates were obtained. Both side portions at both ends in the length direction of the object were welded 30 mm in length to fix the laminated materials to each other. Next, the laminate was heated to 480 ° C., and hot clad rolling was performed by passing between the rolling rolls a plurality of times. Note that the reduction rate in this hot clad rolling starts from a ratio of 1% with respect to the thickness of the laminate, and the reduction rate is 10% in the tenth pass while increasing the reduction rate sequentially. did. Moreover, the reverse rolling which reverses a rolling direction for every pass was employ | adopted for rolling. Also, the clad material No. In the manufacture of No. 2, the first four passes are unidirectionally rolled and reverse rolling is applied from the fifth pass. In No. 12, hot clad rolling was performed by center rolling which starts rolling from the central part in the longitudinal direction of the laminate. In any material, the thickness is hot rolled up to 3 mm, the end cracked portion is deleted, and a hot rolled sheet having a width of 150 mm is further thickened with a cold rolling mill. The target clad material was manufactured by rolling to 1 mm and then applying a softening treatment at 400 ° C. for 2 hours. In addition, in the manufacturing process of this clad material, in the case where there has been noticeable peeling during the hot rolling operation, or in the case where it has become impossible to continue due to unbonding of the bonding interface, the hot rolling operation is in progress. Canceled.

  Each of the various aluminum clad materials after the softening treatment thus obtained was inspected for appearance, evaluated for peeling and swelling occurrence and surface smoothness, and shown in Tables 5 to 7 below. In addition, the position of 150 mm from the one end portion in the longitudinal direction (tip portion in the rolling direction) and the other end portion (rear end portion in the rolling direction) of the obtained clad material, and the position in the center portion in the longitudinal direction In three places, a cross-sectional observation was carried out in each of nine places, the left and right ends and the center part in the width direction of the clad material, and the clad rates of the Al skin material and Al intermediate material were measured. 5 to Table 7 are also shown. In the evaluation of the clad rate, ◎ indicates that the clad rate distribution is extremely small and is extremely valuable as a clad material, and ○ indicates that the clad rate distribution is small and is a good clad material. Furthermore, Δ indicates that the distribution of the cladding rate is slightly increased and the number of sites to be excised is increased, and × indicates that the distribution of the cladding rate is large and therefore lacks practicality. .

  As apparent from the results in Tables 2 to 4 and Tables 5 to 7, the aluminum clad material No. 1 obtained in accordance with the present invention was used. In Nos. 1 to 17, almost no peeling or swelling was observed, and there was almost no problem with the smoothness of the surface. Furthermore, in the distribution of the cladding ratio (difference between the maximum value and the minimum value of the cladding ratio), it is almost within 10% of the target value of the cladding ratio (if the target is 10%, the maximum value and the minimum value of the cladding ratio). Difference was within 1%).

  Specifically, the clad material No. 1 is 0.9%, while the clad material No. 1 obtained by unidirectional rolling up to four passes in the initial rolling stage is 0.9%. Although the difference in the cladding ratio in No. 2 increased to 2.1%, no. Compared with a clad material of 18 or less, the clad rate distribution was uniform, and neither peeling nor blistering was observed.

  In addition, the clad material No. manufactured using a clad rate that is difficult or impossible to manufacture at the factory. Also in 4-6, it was confirmed that a good quality aluminum clad material could be obtained without problems, and the clad rate limitation which is generally limited to the range of about 5-25% is greatly reduced by the present invention. It became clear that it was eased.

  In addition, no. No. 7 clad material (the core material and the skin material are the same material), No. 7 No. 8 clad material (material whose core material is soft and easy to stretch and whose skin material is easy to break) and No. 8 It was confirmed that good results could be obtained even with 9 to 12 clad materials (the core material and the skin material were the same material and the clad rollability was poor). In particular, no. In the clad materials 9 to 12, the surface treatment (chemical treatment or mechanical treatment) of the core material, the point-like thick member, or the skin material is effective, and the surface treatment and the rolling process are optimized. In the clad material according to No. 12, it was confirmed that a highly uniform clad rate distribution was obtained.

  Further, according to the present invention, both the aluminum clad material (No. 13), the aluminum clad material (No. 14) having an intermediate layer, and the clad material (No. 15) having the heat treatment type alloy as the core material are good. It was confirmed that the result was obtained. Therefore, from these results, it is clear that, in addition to the relaxation of the clad rate constraint, according to the present invention, the constraint was relaxed in the materials and configurations that were conventionally difficult to perform clad rolling. .

  On the other hand, No. which is a comparative example. In the clad material of 18 or less, various problems are inherent. That is, the clad material No. 18 and No. In FIG. 19, the clad rolling has a low degree of difficulty, and it was possible to perform clad rolling without using the point-like thick member according to the present invention. The rate has a difference exceeding 30% with respect to the target value. In such a clad material, if the swelling portion is removed and the portion where the clad rate is outside the allowable range is removed, the product can be used as a product, but the yield is greatly deteriorated. .

  Also, the clad material No. 20 and no. In No. 21, the clad rate was low, and no point-like thick member was used, so clad rolling could not be performed. Similarly, the clad material No. 22, clad rolling became possible by using a point-like thick member, but a point-like thick member having a thick point-like thick part was used for a soft and thin skin material. Therefore, it is recognized that fine irregularities are generated on the surface of the obtained aluminum clad material, and the clad rate is partially lowered due to partial biting of the point-like thick member into the skin material. Furthermore, the clad material No. In No. 23, the clad ratio was high, and no point-like thick member was used, so that the clad rolling could not be performed.

  Further, the clad material No. 24 and no. No. 25 is the same material in which the core material and the skin material are soft. In No. 24, since a point-like thick member is not used, clad rolling cannot be performed. 25, since the dotted thick parts of the used dotted thick members are thin and the interval between the dotted thick parts is narrow, the grip effect by the dotted thick members cannot be effectively exhibited, As a result, peeling occurred. In addition, the clad material No. 26 employs a highly difficult clad structure with soft pure aluminum as a core material and soft and easy to generate micro cracks as a skin material. Since the member was not used, it was confirmed that the core material and the skin material were insufficiently bonded, the skin material was peeled off, and micro cracks were generated throughout the skin material.

  And the clad material No. with very high difficulty of clad rolling. In the structure of 27 to 28 (the core material and the skin material are the same material containing high Mg), it is impossible to manufacture unless a point-like thick member is used, and even if a point-like thick member is used, When the thick-walled member is outside the specified range of the present invention, the quality is deteriorated.

  In addition, both the double-sided aluminum clad material (No. 29) and the aluminum clad material (No. 30) whose heat-treatable aluminum alloy is an Al core material do not use a point-like thick member. . In No. 29, blisters were generated, and the clad rate distribution was poor. No. 30 resulted in a production failure.

(Example 2)
Among the alloy materials shown in Table 1, a combination of Al skin: pure aluminum / Al core: Al—Zn—Mg—Cu alloy and Al skin: Al—Mg alloy / Al core: Al—Mg. An alloy combination was selected, and as shown in Table 8 below, two clad materials were manufactured for each combination. Here, as for the Al core material, an ingot formed by continuous casting is chamfered to obtain a thickness: 380 mm × width: 400 mm × length: 600 mm, and an Al skin material (brazing material). About, about what was hot-rolled to the thickness of 20 mm after casting and cut | disconnected in the dimension of width: 400mm x length: 600mm was used. Further, as the point-like thick member, a plain woven wire mesh made of an Al-Mg alloy having an Mg content of 4 or 6% by mass, similar to Example 1, is used in the configuration shown in Table 8 below. It was.

  For the production of one of the two clad members, the periphery of the boundary (outer peripheral edge portion) between the Al core material and the Al skin material was partially fixed by welding in the same manner as in Example 1, and then predetermined. Heating to temperature, the clad rolling was started at a target clad rate of 5%. For the production of another clad material, the periphery of the boundary between the Al core material and the Al skin material is welded over the entire circumference, while Al is passed through an exhaust pipe attached by welding to the center of one end in the longitudinal direction. After the intervening air is exhausted from the interface between the core material and the Al skin material, the pressure is reduced to 2 Pa, the exhaust pipe is crushed and sealed, and then heated to a predetermined temperature in the same manner as in Example 1 to obtain a target cladding ratio: Clad rolling was started at 5%. In hot rolling of aluminum, an emulsion in which water and oil are generally mixed is used as a lubricant. Therefore, in the clad rolling of this example, an emulsion is used in a conventional manner. .

  The clad materials thus obtained were evaluated in the same manner as in Example 1, and the results are shown in Table 9 below.

  By the way, in the hot rolling of the clad material as described above, when the used emulsion enters the interface of the laminated material, it becomes a cause of generating blisters. In order to prevent the emulsion from entering the interface, it is effective to discharge the air remaining at the interface with the progress of rolling. In order to widen the outlet, the Al core material and the Al skin material are used. It is preferable to use partial welding or to perform hot rolling without welding and fixing the clad material No. in Tables 8 and 9. As shown in 31 and 32, it is recognized that in the case where the Al core material and the Al skin material are partially welded and fixed, neither peeling nor swelling occurs, and there is no problem in the smoothness of the surface. .

  On the other hand, the clad material No. As is clear from the examination of 33 and 34, both the circumference of the boundary between the Al core material and the Al skin material is welded over the entire circumference, and the clad rolling is performed in a state where the joint interface is decompressed, It was observed that bulges were concentrated at the end in the width direction, and bulges were also generated in a part near the center in the width direction. In this way, when the circumference of the laminate is welded all around and the joint interface is depressurized, the high-temperature atmosphere containing oil particles and water vapor rapidly rises from the cracked portion of the weld bead that occurs during hot-clad rolling. Intrusions into the bonding interface, hindering the bonding at the interface and generating blisters. From this result, it is understood that, in the clad rolling of the aluminum material, the quality of the clad material is remarkably deteriorated by adopting a method of reducing the pressure at the joint interface.

From the above results, according to the present invention, it is clear that the productivity improvement effect and the quality improvement effect of the target aluminum cladding material can be advantageously achieved, thereby greatly increasing the manufacturing cost of the aluminum cladding material. It is understood that it can be reduced to In addition, an aluminum clad material, which has been difficult to manufacture in the past, can be manufactured, and a material having strength, formability, corrosion resistance, and the like can be designed. The aluminum clad material obtained according to the present invention is expected to be widely used in various fields such as structures for transport equipment, drive systems and control system parts, multifunctional materials for electronic equipment, and high performance materials for heat exchangers. is there.

Claims (7)

An Al core material made of aluminum or an aluminum alloy is laminated on one or both surfaces of an aluminum core material made of aluminum or aluminum alloy, and the resulting laminate is hot-rolled to form an Al core material and an Al skin. When manufacturing an aluminum clad material formed by joining and integrating materials,
Thickness constituted by intersections of these vertical lines and horizontal lines obtained by using Al wires made of aluminum or aluminum alloy as vertical lines and horizontal lines and intersecting them in a grid pattern: 0. A dotted thick member having a structure in which 2 to 3.2 mm dotted thick portions are arranged at intervals of 0.2 to 13 mm in two vertical and horizontal directions is used as a bonding interface between the Al core material and the Al skin material. While interposing and constituting the laminate, the Al interface, the dotted thick member, and the Al skin are partially fixed or not fixed at the outer periphery of the Al interface, and the bonding interface is in the atmosphere. A method for producing an aluminum clad material, wherein the laminate is hot-rolled in a state where the laminate is in communication therewith.   The method for producing an aluminum clad material according to claim 1, wherein the Al wire has a wire diameter of 0.1 to 1.6 mm.   The method for producing an aluminum clad material according to claim 1 or 2, wherein the Al wire is formed of an Al-Mg alloy containing 1.5 to 6% by mass of magnesium.   4. The Al wire constituting the dotted thick member has an oxide film on the surface thereof chemically destroyed and removed by treatment with an acid solution or an alkali solution. The manufacturing method of the aluminum clad material of any one of these.   The hot rolling is performed by passing the laminate a plurality of times between a pair of rolling rolls, and the rotation directions of the rolling rolls in the odd-numbered pass and the even-numbered pass are opposite to each other. The method for producing an aluminum clad material according to any one of claims 1 to 4, wherein the rolling is performed by reverse rolling in which the rolling directions are alternately reversed.   After the laminate is inserted between a pair of rolling rolls in an unloaded state, the hot rolling is performed by applying a load to the laminate and then rotating the rolling roll, and the rolling roll The production of an aluminum clad material according to any one of claims 1 to 5, wherein reverse rolling is performed so that the rotation directions of the rolling rolls are opposite to each other each time the sheet is passed. Method. A plate-like Al intermediate material made of aluminum or an aluminum alloy is further interposed between the Al core material and the Al skin material, and between the Al core material and the Al intermediate material, and between the Al intermediate material and the Al intermediate material. The dotted thick member is disposed between at least one of the Al skin materials, and the Al core material, the Al intermediate material, the dotted thick member, and the Al skin material are disposed at the outer peripheral portion thereof. The method for producing an aluminum clad material according to any one of claims 1 to 6, wherein the laminate is configured to be partially fixed or not fixed.