JP5573074B2 - Aluminum alloy sheet manufacturing method, aluminum alloy sheet material, and aluminum alloy sheet manufacturing apparatus - Google Patents

Description

  The present invention relates to a method for producing an aluminum alloy sheet.

  2. Description of the Related Art Conventionally, high-strength thin steel plates called ultra-high strength with high strength have been used as plate materials used for automobile bodies. This ultra-high tensile strength is high but heavy. Therefore, the use of an aluminum alloy that is lighter in weight than a steel plate has been studied as the plate material.

  A plate made of an aluminum alloy, that is, an aluminum alloy plate is manufactured using a DC (Direct Hill) method or a continuous casting and rolling method (CC method: Continuous Casting method). The DC method starts with melting aluminum raw material, and obtains an aluminum plate through the steps of slab casting, homogenization treatment, chamfering, heating, hot rolling, and cold rolling. The CC method is a method in which an aluminum alloy plate is directly manufactured from a molten metal in which an aluminum alloy raw material is melted. This CC method has various advantages such as fewer steps than the DC (Direct Chill) method, cost and energy input can be kept small, and material properties can be improved. One of the typical CC methods is a twin-roll continuous casting and rolling method. In this twin-roll type continuous casting and rolling method, a molten aluminum alloy is supplied between a pair of casting rolls, that is, twin rolls, and the aluminum alloy is rolled and solidified between the twin rolls to form a plate. For example, Patent Document 1 discloses a twin-roll continuous casting and rolling method that adjusts the peripheral speed and the like of a twin roll within a predetermined range in order to suppress the generation of blisters.

JP 2009-136895 A

  A plate material used for an automobile body or the like is required to be lightweight and strong. On the other hand, the aluminum alloy material is lightweight but relatively low in strength. Thus, for example, it is conceivable to secure the strength by bonding a reinforcing member to a thin aluminum alloy plate material manufactured by the conventional CC method as described above. However, in this case, it is necessary to prepare a reinforcing member separately and to perform a connecting operation of the reinforcing members, which is troublesome in terms of cost and labor.

In order to solve the above-mentioned problems, the present invention provides a manufacturing method for manufacturing an aluminum alloy sheet, a molten metal supplying step for supplying a molten aluminum alloy between a pair of casting rolls, and the rotating casting roll. A casting and rolling step of forming a plate-like aluminum alloy material by solidifying and rolling the aluminum alloy by passing the aluminum alloy in between, and after the casting and rolling step, at least of the aluminum alloy material A rolling process in which a part is cold- rolled with a rolling roll, and is performed after the rolling process, and the temperature of the entire aluminum alloy material is maintained at a predetermined temperature equal to or higher than a recrystallization temperature, and then the aluminum alloy material is maintained at the predetermined temperature. and a heat treatment step of annealing at lower and temperature higher than the recrystallization temperature, in the casting and rolling process, the aluminum When the aluminum alloy passes between the casting rolls, the distance between the casting rolls is varied depending on the part of the aluminum alloy, thereby forming an aluminum alloy material having parts with different thicknesses in the alignment direction of the casting rolls. In the rolling step, an aluminum alloy sheet manufacturing method is provided, wherein at least a portion of the aluminum alloy material whose thickness is thicker than other portions is rolled (Claim 1).

  According to this method, the strength of the aluminum alloy material can be locally increased to obtain a lightweight and strong aluminum alloy plate, and the number of reinforcing members for increasing the strength of the aluminum alloy plate can be reduced. Therefore, the labor for connecting the reinforcing members can be reduced.

In other words, in this method, portions having different thicknesses are formed in the plate-like aluminum alloy material, that is, the aluminum alloy plate material, in the casting and rolling process. Therefore, by rolling this aluminum alloy sheet material in the rolling process, the degree of processing and the strength of each part can be varied according to the difference in thickness. Thereafter, by performing a heat treatment at a temperature higher than the recrystallization temperature, the aluminum alloy sheet is recrystallized using the processing strain applied in the rolling step as a driving force. The recrystallized grain size in the recrystallization varies depending on the degree of work given in the rolling step, and becomes finer as the degree of work is larger. The finer the crystal grains, the higher the strength and the better the toughness. Therefore, the characteristics of the aluminum alloy material at a portion with a high degree of workability are improved in the rolling process. In this way, it is possible to form a portion with high strength and a portion with relatively low strength but light weight in the aluminum alloy sheet. Further, the strength and ductility of the aluminum alloy material can be secured at the same time by the generation of the recrystallized grains.

  In the present invention, as the pair of casting rolls, at least one casting roll of the casting roll has a small diameter portion adjacent to each other along the axial direction and a large diameter portion having a larger roll diameter than the small diameter portion. In the casting and rolling step, an aluminum alloy is passed between one casting roll having the small diameter portion and the large diameter portion and the other casting roll, and the small diameter of the aluminum alloy material is used. It preferably includes a step of making the thickness of the part formed by passing through the part thicker than the part formed by passing through the large diameter part having a larger roll diameter than the small diameter part (Claim 2). .

  In this way, by passing the aluminum alloy between the casting rolls, the thick part and the thin part can be formed adjacent to each other along the direction orthogonal to the rolling direction by the casting roll. An aluminum alloy material whose strength changes along a direction orthogonal to the rolling direction can be obtained.

  Moreover, in the present invention, the casting and rolling step includes moving the casting rolls in directions away from each other while the aluminum alloy is passing between the casting rolls. It is preferable to include a step of making the thickness of the portion formed by passing between the casting rolls after the movement thicker than the thickness of the portion formed by passing between the casting rolls before moving the casting roll. (Claim 3).

  In this way, by a simple method of moving the casting rolls away from each other, a thick part and a thin part can be formed adjacent to each other along the rolling direction of the casting roll, An aluminum alloy sheet material whose strength changes along the rolling direction can be obtained.

  In the present invention, it is preferable that in the rolling step, the entire aluminum alloy material is rolled so as to have a uniform thickness.

  In this way, it is possible to obtain an aluminum alloy sheet having a constant thickness and locally different strength.

Further, the present invention is a single aluminum alloy sheet produced by the method for producing an aluminum alloy sheet, and is adjacent to a high strength portion extending in a specific direction and a direction orthogonal to the high strength portion and the specific direction. A low-strength portion having a lower strength than the high-strength portion and extending along the specific direction, and the specific direction is orthogonal to the rolling direction of the casting roll or the rolling direction. providing an aluminum alloy sheet, characterized in that the direction (claim 5).

  The strength of the aluminum alloy sheet is locally increased, and the use of this aluminum alloy sheet can suppress deformation against a light collision load. Therefore, depending on the case, the number of reinforcing members for increasing the strength of the aluminum alloy sheet can be reduced, and the labor for joining the reinforcing members can be reduced. In particular, a high-strength portion having high strength extends along a specific direction, and the strength of the aluminum alloy sheet can be increased along this direction.

In the aluminum alloy plate material, provided at a position adjacent to the high-strength portion in the specific direction, adjacent to the high-strength portion higher in strength than the high-strength portion, the low-strength portion and the specific direction. A second high-strength portion provided at a position adjacent to the high-high-strength portion and a direction orthogonal to the specific direction, and having a strength higher than the low-strength portion and lower than the high-high-strength portion; It is preferable to have (claim 6 ).

  In this configuration, the high-strength portion and the high-high-strength portion with relatively high strength are arranged along the specific direction, and the second high-strength portion and the high-high-strength portion with relatively high strength along the direction orthogonal to the specific direction. In addition to the specific direction, the strength of the aluminum alloy sheet can be increased along the direction orthogonal to the specific direction.

Further, the present invention is a manufacturing apparatus for manufacturing an aluminum alloy plate material, wherein a storage portion capable of storing a molten aluminum alloy, and a plate-shaped aluminum alloy melt supplied from the storage portion by rolling. Cold- rolling a pair of casting rolls capable of forming an aluminum alloy material, supply means capable of supplying molten aluminum alloy from the storage portion between the casting rolls, and the aluminum alloy material formed between the casting rolls A pair of possible rolling rolls and the temperature of the entire aluminum alloy material rolled by the rolling rolls are maintained at a predetermined temperature equal to or higher than the recrystallization temperature, and then the aluminum alloy material is lower than the predetermined temperature and higher than the recrystallization temperature. and a heat treatment apparatus for annealing at a temperature, at least one of the casting rolls of the pair of casting rolls along its axial direction each other To have a greater large diameter portion of the roll diameter than the small diameter portion and the small diameter portion adjacent to provide an apparatus for manufacturing an aluminum alloy sheet, wherein (claim 7).

  According to this apparatus, by passing the aluminum alloy between the casting rolls, the thickness of the part formed by passing through the small diameter portion of the aluminum alloy sheet material formed by the passage is more roll than the small diameter portion. The thickness of the aluminum alloy sheet can be changed along the direction perpendicular to the rolling direction by the casting roll by passing through the large-diameter portion having a large diameter. And, by rolling the aluminum alloy sheet having parts having different thicknesses, the degree of processing of each part and thus the strength can be varied according to the difference in thickness. Can form a relatively low but lightweight part. In particular, the thickness of the aluminum alloy sheet can be changed along the direction perpendicular to the rolling direction of the casting roll, and an aluminum alloy sheet with high strength can be obtained along the direction perpendicular to the rolling direction.

Further, the present invention is a manufacturing apparatus for manufacturing an aluminum alloy plate material, wherein a storage portion capable of storing a molten aluminum alloy, and a plate-shaped aluminum alloy melt supplied from the storage portion by rolling. Cold- rolling a pair of casting rolls capable of forming an aluminum alloy material, supply means capable of supplying molten aluminum alloy from the storage portion between the casting rolls, and the aluminum alloy material formed between the casting rolls A pair of possible rolling rolls and the temperature of the entire aluminum alloy material rolled by the rolling rolls are maintained at a predetermined temperature equal to or higher than the recrystallization temperature, and then the aluminum alloy material is lower than the predetermined temperature and higher than the recrystallization temperature. a heat treatment device for annealing at a temperature, at least one of the casting rolls of the pair of casting rolls, contact to the other casting roll Further comprising a moving means for moving in a direction to provide an apparatus for manufacturing an aluminum alloy sheet, wherein (claim 8).

  According to this apparatus, by passing the aluminum alloy between the casting rolls, the thickness of the portion formed by passing between the casting rolls after the casting rolls are moved among the aluminum alloy sheet material formed by the passing. Can be made thicker than the thickness of the portion formed by passing between the casting rolls before moving the casting roll. And, by rolling the aluminum alloy sheet having parts having different thicknesses, the degree of processing of each part and thus the strength can be varied according to the difference in thickness. Can form a relatively low but lightweight part. In particular, the thickness of the aluminum alloy sheet can be changed along the rolling direction of the casting roll, and a high-strength aluminum alloy sheet can be obtained along the rolling direction.

In the apparatus, at least one casting roll of the pair of casting rolls preferably includes a small diameter portion adjacent to each other along an axial direction thereof and a large diameter portion having a larger roll diameter than the small diameter portion. 9 ).

  In this way, by passing the aluminum alloy between the casting rolls, the thickness of the aluminum alloy sheet can be changed along the direction perpendicular to the rolling direction in addition to the rolling direction by the casting roll, In addition to the rolling direction by the casting roll, a high-strength aluminum alloy sheet can be obtained along the direction orthogonal to the rolling direction.

  As described above, according to the present invention, it is possible to manufacture an aluminum alloy sheet material that is lightweight and has sufficient strength.

It is a schematic block diagram of the manufacturing apparatus of the aluminum alloy board | plate material which concerns on this invention. It is a schematic side view of a pair of casting roll which concerns on 1st Embodiment of this invention. It is a schematic side view which shows the state which the casting roll shown in FIG. 2 moved to the 2nd position. It is a schematic plan view of the aluminum alloy sheet after the rolling casting process. It is the VV sectional view taken on the line of FIG. It is the VI-VI sectional view taken on the line of FIG. It is the VII-VII sectional view taken on the line of FIG. It is the VIII-VIII sectional view taken on the line of FIG. (A) It is a photograph which shows the metal structure of the cross section of the aluminum alloy plate material without cold rolling and heat processing. (B) It is a photograph which shows the metal structure of the cross section of the aluminum alloy sheet material which performed only the heat processing without performing cold rolling. (C) It is a photograph which shows the metal structure of the cross section of the aluminum alloy plate material which is not heat-treated while performing cold rolling. (D) It is the metal structure photograph of the cross section of the aluminum alloy plate material which heat-processed after giving cold rolling. It is a schematic plan view of the aluminum alloy plate manufactured by the manufacturing method according to the second embodiment of the present invention. It is a figure which shows the example of application of the aluminum alloy board | plate material shown in FIG. (A) It is a figure which shows the example of application of the aluminum alloy board | plate material shown in FIG. (B) It is a side view of (a). It is a figure which shows the other example of application of the aluminum alloy board | plate material shown in FIG. It is a schematic side view of a pair of casting roll used in the manufacturing method which concerns on 3rd Embodiment of this invention. It is a figure which shows the example of application of the aluminum alloy plate manufactured by the manufacturing method which concerns on 3rd Embodiment of this invention. It is a figure which shows the other example of application of the aluminum alloy plate manufactured by the manufacturing method which concerns on 3rd Embodiment of this invention. It is a schematic side view of a pair of casting roll used in the manufacturing method which concerns on 4th Embodiment of this invention. It is a schematic plan view of the aluminum alloy plate manufactured by the manufacturing method according to the fourth embodiment of the present invention. It is a schematic side view of a pair of casting roll used in the manufacturing method concerning other embodiments of the present invention. It is a schematic side view of a pair of casting roll used in the manufacturing method concerning other embodiments of the present invention. It is a schematic side view of a pair of casting roll used in the manufacturing method concerning other embodiments of the present invention.

  Hereinafter, a preferred first embodiment of a method for producing an aluminum alloy sheet according to the present invention will be described with reference to the drawings. In this method for manufacturing an aluminum alloy sheet, a manufacturing apparatus (a manufacturing apparatus for an aluminum alloy material) 1 shown in FIG. 1 is used.

  The manufacturing apparatus 1 includes a tundish 5, a nozzle 2, a twin roll, that is, a pair of casting rolls 22, 24, a casting roll moving means (moving means) 30, a feed roll 40, and a pair of rolling rolls 52, 54. And a heat treatment furnace 60.

  The tundish 5 is for storing a molten aluminum alloy. The nozzle 2 is for supplying a molten aluminum alloy 100 from the tundish 5 to the casting rolls 22 and 24. The nozzle 2 extends from the tundish 5 so that the tip of the nozzle 2 faces the casting rolls 22 and 24.

  The casting rolls 22 and 24 are for forming a plate-like aluminum alloy material, that is, an aluminum alloy plate material 102, by rolling the aluminum alloy melt 100 while cooling and solidifying it. These casting rolls 22 and 24 are rolls rotating in opposite directions to each other, and are arranged in a state in which respective axes extending in the horizontal direction are arranged in parallel in the vertical direction. The casting rolls 22 and 24 have different shapes.

  As shown in FIG. 2, the first roll 22 provided on the upper side has a shape in which the roll diameter changes in the axial direction. Specifically, the first roll 22 includes a small-diameter portion 22a having a small roll diameter provided at the center in the axial direction, and two roll diameters larger than the small-diameter portion 22a at both ends in the axial direction across the small-diameter portion 22a. It has large diameter portions 22b and 22c. The large diameter portions 22b and 22c have the same roll diameter. On the other hand, the second roll 24 provided on the lower side has a columnar shape with a constant roll diameter in the axial direction. Accordingly, the separation distance between the small diameter portion 22 a and the second roll 24 is larger than the separation distance between the large diameter portions 22 b and 22 c and the second roll 24.

  The twin roll moving means 30 is for changing the separation distance between the first roll 22 and the second roll 24. The twin roll moving means 30 changes the separation distance between the first roll 22 and the second roll 24 by moving the shaft 22 d of the first roll 22 in the vertical direction along the rail 32. Specifically, the twin-roll moving means 30 is configured to move the first roll 22 above the first position indicated by the solid line in FIG. 2 and the two-dot chain line in FIG. 3 by a distance h from the first position. That is, it is moved between the second position indicated by the solid line in FIG. 3 set in a direction away from the second roll 24.

  In the first position, the distance between the small diameter portion 22a of the first roll 22 and the second roll 24 is d1, and the distance between the large diameter portions 22b and 22c and the second roll 24 is d2 ( <D1). On the other hand, in the second position, the second roll 24 moves upward by the moving distance h, so that the separation distance between the small diameter portion 22a and the second roll 24 becomes d1 + h (> d1), and the large diameter portion 22b. , 22c and the second roll 24 are d2 + h (> d2). In the present embodiment, the moving distance h is set to a value smaller than d1-d2, and the separation distance d1 between the small diameter portion 22a and the second roll 24 at the first position is the second position. Is larger than the separation distance d2 + h between the large diameter portions 22b and 22c and the second roll 24.

  The feed roll 40 is a roll for feeding the aluminum alloy plate material 102 discharged from the casting rolls 22 and 24 to the rolling rolls 52 and 54.

  The rolling rolls 52 and 54 are for rolling the aluminum alloy sheet material 102 fed by the feed roll 40 to have a predetermined thickness. These rolling rolls 52 and 54 are rolls rotating in directions opposite to each other, and are arranged in a state in which respective axes extending in the horizontal direction are arranged in parallel vertically. Each of these rolling rolls 52 and 54 has a cylindrical shape whose roll diameter is constant in the axial direction, and the separation distance between the rolling rolls 52 and 54 is constant t in the axial direction.

  The method of manufacturing an aluminum alloy sheet using the manufacturing apparatus 1 configured as described above includes the following steps.

(1) Molten metal supply process In this process, the molten aluminum alloy 100 stored in the tundish 5 is supplied from the tip of the nozzle 2 between the first roll 22 and the second roll 24.

(2) Casting and rolling step In this step, a plate-like aluminum alloy material, that is, an aluminum alloy plate material 102 is formed from the molten aluminum alloy 100.

  The molten aluminum alloy 100 supplied from the nozzle 2 between the first roll 22 and the second roll 24 passes between the rolls 22 and 24 and is downstream as the first roll 22 and the second roll 24 rotate. Will be sent to the side. The first roll 22 and the second roll 24 are cooled by flowing cooling water therein. The molten aluminum alloy 100 passes between the first roll 22 and the second roll 24 and is rolled while contacting and cooling and solidifying the rolls 22 and 24, and the rolls 22 and 24 are separated from each other. It is formed into an aluminum alloy plate material 102 having the same thickness as the distance (thickness in the direction in which the rolls 22 and 24 are arranged).

  In this step, the roll moving means 30 moves the position of the first roll 22 while the molten aluminum alloy 100 stored in the tundish 5 passes between the first roll 22 and the second roll 24. Switching between the first position and the second position.

  As described above, in the state where the first roll 22 is in the first position, the separation distance between the first roll 22 and the second roll 24 is d1 in the small diameter portion 22a, and the large diameter portions 22b and 22c. D2. Therefore, the thickness of the site | part formed by passing between the said small diameter part 22a and the 2nd roll 24 in the state which has the 1st roll 22 in the 1st position among the aluminum alloy board | plate materials 102 becomes d1. On the other hand, the thickness of the portion formed by passing between the large diameter portions 22b and 22c and the second roll 24 is d2 (<d1). In this way, in the state where the first roll 22 is in the first position, as shown in FIG. 5, the thickness perpendicular to the rolling direction, that is, the thickness at the center in the width direction is d1, and the thickness at both ends in the width direction is d2. And the board | plate material from which board thickness changes between d1 and d2 along the width direction is shape | molded.

  When the portion where the state at the first position continues for a predetermined time and changes between the plate thicknesses d1 and d2 along the width direction is formed to a predetermined length L1, the roll moving means 30 is moved to the first roll 22. Is moved to the second position. In the state where the first roll 22 is in the second position, the separation distance between the first roll 22 and the second roll 24 is d1 + h in the small diameter portion 22a and d2 + h in the large diameter portions 22b and 22c. Therefore, in this state, the thickness of the part formed by passing between the small diameter portion 22a and the second roll 24 in the aluminum alloy material 102 is d1 + h (> d1). On the other hand, the thickness of the portion formed by passing between the large diameter portions 22b and 22c and the second roll 24 is d2 + h (d2 <d2 + h <d1). Thus, in the state where the first roll 22 is in the second position, as shown in FIG. 6, the thickness perpendicular to the rolling direction, that is, the thickness at the center in the width direction is d1 + h, and the thickness at both ends in the width direction is d2 + h. And the board | plate material from which board thickness changes between d1 + h and d2 + h along the width direction is shape | molded.

  When the state at the second position continues for a predetermined time and the portion that changes between the plate thicknesses d1 + h and d2 + h along the width direction is formed to a predetermined length L2, the roll moving means 30 is moved to the first roll. 22 is again moved to the first position. In this way, the position of the first roll 22 is switched between the first position and the second position at a predetermined timing.

  As described above, in this step, as shown in FIG. 4, the aluminum alloy plate material 102 having a plurality of portions having different plate thicknesses is formed.

  That is, as shown in FIG. 4 and FIG. 7, the second portion A2 and the third portion A3 of the plate thickness d2 (<d1) extending in the rolling direction over the length L1 at both ends in the width direction of the aluminum alloy plate material 102, The fifth part A5 and the sixth part A6 of the plate pressure d2 + h (d2 <d2 + h <d1) extending in the rolling direction over the length L2 respectively in succession to the second part A2 and the third part A3 are alternately formed. Then, as shown in FIGS. 4 and 8, a first portion A1 having a plate thickness d1 extending over the length L1 in the rolling direction at the center in the width direction of the aluminum alloy sheet 102 and rolling continuously to the first portion A1. The fourth portions A4 of the plate pressure d1 + h (> d1) extending in the direction over the length L2 are alternately formed.

(3) Rolling process In this process, the aluminum alloy sheet material 102 formed by the casting and rolling process and then fed to the rolling rolls 52 and 54 by the feed roll 40 is rolled into the rolling roll 52 by the rolling rolls 52 and 54. , 54 are rolled to a separation distance t. This rolling may be cold rolling or hot rolling. In the case of hot rolling, for example, the rolling start temperature is 400 to 550 ° C. The aluminum alloy sheet 102 is inserted between the rolling rolls 52 and 54, and is sent to the downstream side through the rolling rolls 52 and 54 with the rotation of the rolling rolls 52 and 54, so that the sheet thickness is reduced. Rolling is performed so that a separation distance t between 52 and 54 is obtained.

  In this embodiment, the separation distance t between the rolling rolls 52 and 54 is set to be smaller than the thickness d2 of the thinnest portion of the aluminum alloy sheet 102 before being rolled by the rolling rolls 52 and 54. The plate material 102 is made into an aluminum alloy plate material 104 having a constant thickness throughout the rolling process.

  As described above, the thickness of the aluminum alloy plate material 102 before this rolling process is performed differs depending on the part. Therefore, by performing this rolling process, the aluminum alloy plate material 104 is formed with a plurality of portions having a constant plate thickness but different workability. The degree of work is a value represented by (x−t) / x using a plate thickness t after rolling, where x is a plate pressure before rolling, and in the first part A1 to the sixth part A6, before rolling. In the order of the plate pressure, the degree of processing of the fourth part A4> the degree of processing of the first part A1> the degree of processing of the fifth part A5 = the degree of processing of the sixth part A6> the degree of processing of the third part A3 = the fourth part A4. The degree of processing.

  Here, Table 1 shows the results of examining the relationship between the degree of processing and the tensile strength. Table 1 shows the tensile strength when aluminum sheet materials corresponding to A: 6111 (AA standard), B: 6022, and C: 5023 corresponding to different sheet thicknesses were subjected only to heat treatment without rolling. Cold rolling is performed so that a predetermined thickness (sheet thickness after cold rolling) is obtained from the same thickness as the aluminum alloy sheet material without rolling (sheet thickness without rolling). From the tensile strength (tensile strength with rolling) when the heat treatment was performed after this, and from these tensile strengths, the rate of increase in strength (strength increase rate) by carrying out the rolling treatment ((tensile strength with rolling) FIG. 5 shows the results obtained by examining (tensile strength without rolling) / tensile strength with rolling). Moreover, the calculation result of the work degree at the time of performing cold rolling is shown. The treatment conditions for the heat treatment are constant according to the type of aluminum alloy.

  As shown in Table 1, as the degree of processing increases, the rate of increase in strength increases and the strength becomes higher. In FIG. 9, the result of having observed the crystal structure of the cross section of the aluminum alloy board | plate material equivalent to 6022 with the microscope is shown. 9 (a) shows a case where neither cold rolling nor heat treatment is performed, FIG. 9 (b) shows a case where heat treatment is performed without performing cold rolling, and FIG. 9 (c) shows a case where cold rolling is performed while heat treatment is performed. FIG. 9D shows a case where the heat treatment is performed after the cold rolling. In cold rolling, the plate thickness was reduced from 2 mm to 1.1 mm, and the degree of processing was 44%. The heat treatment was quenched in water after solution treatment at 530 ° C. for 2 hours. Here, the magnifications of FIGS. 9A, 9B, 9C, and 9D are the same. As shown in these figures, the recrystallized grains of the aluminum alloy material subjected to the heat treatment after rolling are refined. The finer the crystal grain, the higher the strength. Therefore, it can be said that the strength of the aluminum alloy material is increased by promoting the atomization of the recrystallized grains as the degree of work increases. Further, as the recrystallized grains are atomized, toughness is also improved.

  Thus, the higher the degree of processing, the higher the strength. In the first part A1 to the sixth part A6, the respective strengths are as follows: the strength of the fourth part A4> the strength of the first part A1> the strength of the fifth part A5 = first. The strength increases in the order of the strength of the six portions A6> the strength of the second portion A2 = the strength of the third portion A3.

  Thus, in this rolling process, among the aluminum alloy sheet material 104, the fourth portion A4 is a high strength portion having the highest strength, and the first portion A1 is a high strength portion having the next highest strength, The second portion A2 and the third portion A3 are the second high strength portions having the next highest strength, the fifth portion A5 and the sixth portion A6 are the lowest strength portions having the lowest strength, and have different strengths depending on the portions. The aluminum alloy plate material 104 is formed.

(4) Heat treatment step In this step, the rolled aluminum alloy sheet 104 is heat treated. That is, the aluminum alloy sheet 104 extruded from the rolling rolls 52 and 54 is conveyed into a heat treatment furnace 60 maintained at a predetermined temperature, and left in the heat treatment furnace 60 for a predetermined time. Specifically, when a 6000 series aluminum alloy is used, a solution treatment is performed in which water quenching is performed after being left in a furnace at 500 to 550 ° C. for 1 hour or longer. When a 5000 series aluminum alloy is used, a homogenization treatment is performed by leaving it in a furnace at 480 to 540 ° C. for 4 to 10 hours or more. When using a 3000 series aluminum alloy, the homogenization process which is left to stand for 4 to 24 hours or more in a 530-610 degreeC furnace is performed. When 1000 series aluminum alloy is used, homogenization treatment is performed in a furnace at 500 to 560 ° C. for 1 to 10 hours or more. Further, after this solution treatment or homogenization treatment, annealing treatment is performed at 340 ° C. or higher. By performing such a heat treatment, recrystallization occurs in the aluminum alloy sheet using the processing strain applied in the rolling step as a driving force. The recrystallized grain size in this recrystallization is refined according to the degree of work given in the rolling step, that is, the greater the degree of work. The finer the crystal grains, the higher the strength and the better the toughness. Therefore, the characteristics of the portion with a high degree of workability are particularly improved in the rolling process.

  As described above, in the manufacturing method of the present aluminum alloy plate material, an aluminum alloy plate material that is a single continuous aluminum alloy plate material and that has a uniform plate thickness but has different strength depending on the part is manufactured.

  The moving distance h of the first roll 22 may be set to the same value as d1-d2. In this case, the distance d1 between the small diameter portion 22a and the second roll 24 at the first position and the distance d2 + h between the large diameter portions 22b and 22c and the second roll 24 at the second position are the same dimensions. Thus, the first portion A1, the fifth portion A5, and the sixth portion A6 have the same strength. On the other hand, the moving distance h of the first roll 22 may be set to a value greater than d1-d2. In this case, the separation distance d2 + h between the large diameter portions 22b and 22c and the second roll 24 at the second position is larger than the separation distance d1 between the small diameter portion 22a and the second roll 24 at the first position. The strength of the first part A1 becomes higher than that of the fifth part A5 and the sixth part A6.

  Here, the temperature of the molten aluminum alloy 100 stored in the tundish 5 and the peripheral speeds of the first roll 22 and the second roll 24 can be set as appropriate. For example, the molten metal temperature is maintained at 670 ° C. or higher. It is preferable. Moreover, it is preferable that the peripheral speed of the 1st roll 22 and the 2nd roll 24, a rolling load, and the distance between rolls are 0.5-100 m / min, 15 kN / mm or less, and 10 mm / less.

  Next, a second embodiment of the method for producing an aluminum alloy sheet according to the present invention will be described. The manufacturing method according to the second embodiment differs from the manufacturing method according to the first embodiment in the content of the casting and rolling process. In the method according to the second embodiment, the position of the first roll 22 is not switched by the roll moving means 30, and the position of the first roll 22 is fixed at the first position.

  In the method according to the second embodiment, the position of the first roll 22 is fixed to the first position, so that in the casting and rolling step, as shown in FIG. ) An aluminum alloy plate material is formed in which the thickness of the portion B1 at the center in the width direction is thicker than the thickness of the portions B2 and B3 at both ends in the width direction. The plate thickness of the central portion B1 of the aluminum alloy plate is d1, and the thicknesses of both end portions B2 and B3 are d2. And the said aluminum alloy material 204 from which the intensity | strength of the center of the width direction is higher than the intensity | strength of the width direction both ends, ie, an intensity | strength changes along a width direction is manufactured by implementing the said rolling process. .

  The aluminum alloy sheet material 204 manufactured in this way is placed on the front and rear sides of the vehicle body under the vehicle floor in order to increase the rigidity of the vehicle body lower portion as shown in FIGS. 11, 12A and 12B, for example. The present invention can be applied to a vehicle body part 500 that extends in a direction and is attached to a vehicle door panel 600 as shown in FIG.

  The vehicle body part 500 has a punched hole 501 formed therein, and upper and lower edges 502 and 503 are bent at right angles in opposite directions as shown in a side view of FIG. Therefore, by applying the portion where the punched hole 501 is formed in the high-strength portion B1 of the aluminum alloy material 204, the upper and lower edges 502 and 503 to be bent are formed in the low-strength portions B2 and B3. The upper and lower edges 502 and 503 can be easily pressed while increasing fatigue strength by increasing the strength around the punched hole 501.

  The panel portion 601 at the lower part of the automobile door panel 600 is required to have dent resistance in consideration of a slight collision. On the other hand, the upper edge 602 of the door panel 600 is bent. Therefore, by forming the panel portion 601 in the high-strength portion B1 of the aluminum alloy material 204 and forming the upper edge portion 602 in the low-strength portion B2, the press working can be easily performed while improving the dent resistance. It can be carried out. In some cases, it is not necessary to attach a reinforcing member to the panel portion 601 in order to increase dent resistance. Alternatively, the number of reinforcing members can be reduced.

  Next, a third embodiment of the method for producing an aluminum alloy sheet according to the present invention will be described. The manufacturing method according to the third embodiment has one small-diameter portion 22a having a roll diameter d1 at the center in the width direction used in the manufacturing methods according to the first and second embodiments. Instead of the first roll 22 having two large diameter portions 22b and 22c with a roll diameter d2 outside the portion 22a, as shown in FIG. 14, it has two small diameter portions 322a and 322b with a roll diameter d1, A first roll 322 having large diameter portions 322c, 322d, and 322e having a total of three roll diameters d2 is used between the small diameter portions 322a and 322b and outside the small diameter portions 322a and 322b.

  By using the first roll 322, in the casting and rolling process, the aluminum alloy plate material has a portion in the width direction where a portion having a plate thickness d1 and a portion having a plate thickness d1 + h are alternately arranged along the rolling direction. Sites are formed at positions spaced apart by a predetermined amount, and between these sites and outside these sites, sites where the thickness changes alternately between d2 and d2 + h along the rolling direction are formed. In the rolling step, the high-strength portions C4 having the highest strength and the high-strength portions C1 having the next highest strength are alternately arranged along the rolling direction (left-right direction in FIG. 15). A high-strength portion side portion C10, and a low-strength portion-side portion C20 in which the low-strength portion C2 having the lowest strength along the rolling direction and the second high-strength portion C5 having the next highest strength are arranged alternately. The aluminum alloy sheet material 304 is formed. At this time, in the width direction, the low-strength portion C2 and the high-strength portion C1 are alternately arranged in the width-direction low-strength portion side portion D20, and the second high-strength portion C5 and the high-strength portion C4 are alternately arranged. A strength portion side portion D10 is formed.

  The aluminum alloy plate material 304 manufactured in this way can be applied to, for example, an automobile door panel 600 or an automobile bonnet outer panel 800 as shown in FIG.

  As shown in FIG. 15, the high-strength portion side portions C <b> 10 are located at both ends in the vertical direction of the panel portion 601 of the door panel 600, and the width-direction high strength portion-side portions D <b> 10 are located at both longitudinal ends of the panel portion 601. If the door panel 600 is manufactured from the aluminum alloy plate material 304 so that the low-strength portion C2 is positioned at the center portion of the panel portion 601, the strength of the end portion of the panel portion 601 can be increased to increase the strength at the time of a vehicle collision or the like. The deformation of the door panel 600 can be suppressed, and the collision energy can be more reliably absorbed by the low strength portion of the central portion. Further, depending on circumstances, the reinforcing member can be reduced without providing the reinforcing member at the end of the panel portion 601.

  In addition, as shown in FIG. 16, the high-strength portion side portions C10 are located at both ends of the bonnet outer panel 800 in the longitudinal direction of the vehicle body. If the part side part D10 is positioned, the strength of these end parts and the central part can be increased and deformation of the bonnet outer panel 800 can be suppressed. Furthermore, depending on the case, the reinforcing member can be reduced without providing the reinforcing member.

  Next, a fourth embodiment of the method for producing an aluminum alloy sheet according to the present invention will be described. In the manufacturing method according to the fourth embodiment, as shown in FIG. 17, a roll having a constant roll diameter in the axial direction is used as the first roll 422, and the first roll 422 and the second roll 24 are separated from each other. A pair of casting rolls whose distance is constant in the axial direction is used.

  By using the first roll 422, in the casting and rolling step, an aluminum alloy plate material in which the plate thickness in the width direction is constant while the plate thickness changes in the rolling direction is formed. In the rolling process, as shown in FIG. 18, the strength in the width direction is constant, while the high strength portion E2 having high strength along the rolling direction and the low strength portion having lower strength than the high strength portion E2. An aluminum alloy plate material 404 in which E1 is alternately arranged is formed.

  As described above, according to the manufacturing method of the present aluminum alloy sheet, it is possible to easily form portions having different strengths in the aluminum alloy sheet, and locally increase the strength of the aluminum alloy sheet, thereby ensuring light weight and strength. The obtained aluminum alloy sheet can be obtained.

  Here, the specific shape of the casting roll is not limited to the above. For example, as shown in FIGS. 19 and 20, the second rolls 524 and 624 may be provided with a small diameter portion and a large diameter portion in addition to the first rolls 522 and 622.

  Moreover, the number of the said small diameter part and the large diameter part is not restricted above. In addition, as shown in FIG. 21, the first roll 722 may be provided with a plurality of small diameter portions 722a and 722b having different roll diameters as the small diameter portion. Similarly, a plurality of large diameter portions having different roll diameters may be provided as the large diameter portion.

  The specific method for separating the first roll and the second roll is not limited to the above. For example, the second roll may be moved.

  Further, the position to move the first roll is not limited to the above. For example, in addition to the first position and the second position, the position may be changed to three or more positions such as moving to the third position. In this case, it is possible to obtain an aluminum alloy sheet whose thickness, that is, strength changes more finely along the rolling direction.

  Moreover, in the said rolling process, you may make it make the workability of this thick part larger than the workability of another part by rolling only a thick part. However, the entire strength can be increased by rolling the entire aluminum alloy sheet. Moreover, processing etc. become easy by making thickness uniform.

  Further, the heat treatment step can be omitted. However, if the aluminum alloy sheet after rolling is heat-treated, properties such as ductility and toughness are improved.

  Moreover, the application of the aluminum alloy plate manufactured by this method is not limited to the above.

1 Aluminum alloy sheet manufacturing equipment 2 Nozzle (supplying means)
5 Tundish (reservoir)
22 First roll (casting roll)
22a Small diameter portion 22b Large diameter portion 22c Large diameter portion 24 Second roll (casting roll)
30 Twin roll moving means (moving means)
52 Rolling Roll 54 Rolling Roll 60 Heat Treatment Furnace 100 Molten Aluminum Alloy 102 Aluminum Alloy Sheet (Before Rolling Process)
104 Aluminum alloy sheet (after rolling process)
A1 High strength part A2 Second high strength part A3 Second high strength part A4 High strength part A5 Low strength part A6 Low strength part

Claims (9)

A manufacturing method for manufacturing an aluminum alloy sheet,
A molten metal supply step of supplying a molten aluminum alloy between a pair of casting rolls;
By passing the aluminum alloy between the rotation to which the casting rolls, the casting and rolling to form a plate-shaped aluminum alloy material the aluminum alloy solidified electrolyte single rolling,
A rolling step that is performed after the casting and rolling step and cold-rolls at least a part of the aluminum alloy material with a rolling roll;
Heat treatment that is performed after the rolling step, maintains the temperature of the entire aluminum alloy material at a predetermined temperature equal to or higher than the recrystallization temperature, and then anneals the aluminum alloy material at a temperature lower than the predetermined temperature and higher than the recrystallization temperature. Process,
In the casting and rolling step, when the aluminum alloy passes between the casting rolls, by changing the distance between the casting rolls according to the location of the aluminum alloy, the thicknesses in the alignment direction of the casting rolls are different from each other. Forming an aluminum alloy material having
In the rolling process, at least a portion of the aluminum alloy material whose thickness is thicker than other portions is rolled. In the manufacturing method of the aluminum alloy plate material of Claim 1,
As the pair of casting rolls, at least one casting roll of the casting roll includes a pair of casting rolls having a small diameter portion adjacent to each other along the axial direction and a large diameter portion having a larger roll diameter than the small diameter portion. Use
In the casting and rolling step, an aluminum alloy is passed between one casting roll having the small diameter part and the large diameter part and the other casting roll, and the small diameter part is passed through the aluminum alloy material. The manufacturing method of the aluminum alloy board | plate material characterized by including the process made thicker than the thickness of the site | part formed by passing the thickness of the site | part formed by passing the large diameter part whose roll diameter is larger than the said small diameter part. In the manufacturing method of the aluminum alloy plate material of Claim 1 or 2,
The casting and rolling step is performed by moving the casting rolls in directions away from each other while the aluminum alloy is passing between the casting rolls. An aluminum alloy sheet material comprising a step of making the thickness of the portion formed by passing through the casting roll thicker than the thickness of the portion formed by passing between the casting rolls before moving the casting roll Production method. In the manufacturing method of the aluminum alloy plate material in any one of Claims 1-3,
In the rolling step, the entire aluminum alloy material is rolled so as to have a uniform thickness. A single aluminum alloy sheet produced by the method for producing an aluminum alloy sheet according to any one of claims 1 to 4,
A high-strength portion extending in a specific direction;
Provided at a position adjacent to the high-strength portion and a direction orthogonal to the specific direction, and includes a low-strength portion extending along the specific direction and having a lower strength than the high-strength portion,
The said specific direction is the rolling direction in the said rolling process, or the direction orthogonal to this rolling direction, The aluminum alloy board | plate material characterized by the above-mentioned. The aluminum alloy sheet according to claim 5,
Provided at a position adjacent to the high-strength portion and the specific direction, the high-strength portion having a higher strength than the high-strength portion,
Provided at a position adjacent to the low-strength part in the specific direction and adjacent to the high-high-strength part and the direction orthogonal to the specific direction, higher than the low-strength part, and higher than the high-high-strength part And a second high-strength portion having a low strength. A manufacturing apparatus for manufacturing an aluminum alloy sheet,
A reservoir capable of storing a molten aluminum alloy;
A pair of casting rolls capable of forming a plate-like aluminum alloy material by rolling a molten aluminum alloy supplied from the storage unit;
Supply means capable of supplying the molten aluminum alloy from the storage section between the casting rolls;
A pair of rolling rolls capable of cold rolling the aluminum alloy material formed between the casting rolls;
A heat treatment apparatus for maintaining the temperature of the entire aluminum alloy material rolled by the rolling roll at a predetermined temperature equal to or higher than a recrystallization temperature, and thereafter annealing the aluminum alloy material at a temperature lower than the predetermined temperature and higher than the recrystallization temperature; With
At least one casting roll of the pair of casting rolls has a small-diameter portion adjacent to each other along the axial direction and a large-diameter portion having a larger roll diameter than the small-diameter portion. apparatus. A manufacturing apparatus for manufacturing an aluminum alloy sheet,
A reservoir capable of storing a molten aluminum alloy;
A pair of casting rolls capable of forming a plate-like aluminum alloy material by rolling a molten aluminum alloy supplied from the storage unit;
Supply means capable of supplying the molten aluminum alloy from the storage section between the casting rolls;
A pair of rolling rolls capable of cold rolling the aluminum alloy material formed between the casting rolls;
A heat treatment apparatus for maintaining the temperature of the entire aluminum alloy material rolled by the rolling roll at a predetermined temperature equal to or higher than a recrystallization temperature, and thereafter annealing the aluminum alloy material at a temperature lower than the predetermined temperature and higher than the recrystallization temperature; ,
An apparatus for producing an aluminum alloy plate material, comprising: a moving means for moving at least one casting roll of the pair of casting rolls in a direction of coming into contact with and separating from the other casting roll. In the manufacturing apparatus of the aluminum alloy sheet material according to claim 8,
At least one casting roll of the pair of casting rolls has a small-diameter portion adjacent to each other along the axial direction and a large-diameter portion having a larger roll diameter than the small-diameter portion. apparatus.