JP6585435B2 - Aluminum alloy plate for forming process excellent in press formability, paint bake hardenability, bendability and recyclability, and manufacturing method thereof - Google Patents

Description

  The present invention is an aluminum alloy for forming process that is excellent in press formability, paint bake hardenability, bendability, and recyclability, and is used as a material for various automobile members and parts such as automobile body sheets and body panels. Regarding the board.

  In recent years, there is an increasing demand for recycling resources in various fields. Since aluminum alloys produced by reducing bauxite are produced by consuming enormous electric power, recycling is required from the viewpoint of resource saving and cost reduction.

  In general, when an aluminum alloy is recycled, impurities tend to increase. For example, in an automobile body panel material, it is assumed that mixing of difficult-to-separate parts such as iron screws used for machine fastening is assumed. Further, from the viewpoint of cost reduction, it is conceivable to use a low-quality scrap material containing a large amount of impurities. On the other hand, in order to satisfy strict required characteristics such as press formability, paint bake hardenability, and bendability required for automobile body panel materials, the amount of impurity elements that can cause deterioration of characteristics is strictly controlled. Is the current situation.

  For example, Patent Document 1 proposes a countermeasure using aluminum alloy scraps and the like. However, in this patent document 1, the stabilization process after the solution treatment aiming at the improvement of the moldability by control of a metal structure and the bake hard property (BH property) is not implemented. As a result, it is difficult to secure the high material properties currently required for automobile body panels and the like, and it has not been put into practical use.

JP 11-293363 A

  The present invention was made against the above circumstances, and is used as a material for various automobile parts and parts such as automobile body sheets and body panels, and is excellent in press moldability, paint bake hardenability, and bendability. And it aims at provision of the aluminum alloy plate for forming which is excellent in recyclability which expanded the tolerance of an impurity element by suppressing the characteristic fall by increase of an impurity element.

  In order to solve the above problems, the inventors have conducted various experiments and studies, and as a result, by combining the appropriate alloy composition and manufacturing conditions, Δr described later is within a predetermined range, thereby improving formability. In addition, the present inventors have also found that high material properties required for materials such as automobile body panels can be secured, and have completed the present invention.

That is, the present invention according to claim 1, Mg: 0.30-0.80 mass%, Si: 0.80-1.40 mass%, Mn: 0.20-0.65 mass%, Zn: 0.44-0 .60 mass%, Fe: 0.25 to 0.40 mass%, Cu: 0.17 to 0.25 mass% and satisfying the following formulas (1) to (3), the balance being an aluminum alloy composed of Al and impurities becomes, rank Ford value Δr satisfies the following (4) showing the anisotropy of (r value) and (5) satisfy the equation, after 100 days of solution treatment, proof stress after performing baking processing than 200MPa , and the and the value obtained by subtracting the yield strength from the tensile strength Ri der least 110MPa, JISH7701: score defined by criteria of hemming tests based on 2008 0-2 points Press formability, characterized in Rukoto, paint-baking hardenability and the bendability and recycling excellent in molding an aluminum alloy plate.
Furthermore, the present invention provides a method for producing an aluminum alloy sheet for forming according to claim 1, wherein the present invention is a casting process for casting the aluminum alloy and a homogenization process for homogenizing the ingot. A hot rolling process for hot rolling the homogenized ingot, an intermediate annealing process for the hot rolled sheet, a cold rolling process for cold rolling the intermediate annealed rolled sheet, and a cold rolled sheet Including a solution treatment step for solution treatment and a stabilization treatment step for stabilizing the solution-treated rolled plate, and the temperature of the solution treatment is 480 ° C. or higher and lower than the melting point of the aluminum alloy, The press formability, paint bake hardenability, and bendability, characterized in that the stabilization treatment step holds the rolled plate heated at a temperature of 80 to 120 ° C. for 1 hour or more within 1 hour after the solution treatment step is completed. Excellent recyclability And as the manufacturing method of molding an aluminum alloy plate.

The above formulas (1) to (5) are as follows.
CSi + CFe + CMn ≦ 2.30 (1)
When CSi / CMg <1.60,
{1.60− (CSi / CMg)} / (CMg ² ) + CFe + CM n ≦ 1.90 (2)
When CSi / CMg ≧ 1.60,
{0.1 / (CMg ² )} + CFe + CM n ≦ 1.70 (3)
−0.50 ≦ Δr ≦ −0.01 (4)
Δr = 1/2 (r0 ° + r90 ° -2 × r45 °) (5)
Here, CSi, CFe, CMn, and CMg indicate the contents of Si, Fe, Mn, and Mg, respectively, r0 ° is an r value in a direction parallel to the rolling direction of the aluminum alloy plate, and r90 ° is an aluminum alloy plate. The r value in the direction perpendicular to the rolling direction, r45 °, indicates the r value in the direction rotated 45 ° from the rolling direction of the aluminum alloy sheet.

  According to the present invention, it is used as a material for various automobile parts and parts such as automobile body sheets and body panels, and is excellent in press formability, paint bake hardenability, bendability, and due to an increase in impurity elements. By suppressing the deterioration of the characteristics, an aluminum alloy plate for forming with excellent recyclability with an increased allowable range of impurity elements can be obtained.

  Hereinafter, embodiments of the present invention will be described in detail.

1. Alloy Composition First, the aluminum alloy composition, which is the material of the aluminum alloy plate, and the reason for limitation will be described.
Mg:
Mg contributes to strength improvement in cooperation with Si. If the Mg content is less than 0.30 mass% (hereinafter, simply referred to as “%”), G. contributes to strength improvement by precipitation hardening during coating baking. P. The amount of zone formation is reduced, and sufficient strength improvement cannot be obtained. On the other hand, if the Mg content exceeds 0.80%, a coarse Mg-Si-based intermetallic compound is generated, and press formability, particularly bending workability is deteriorated. Furthermore, the solid solution of Mg and the formation of intermetallic compounds due to the addition of Mg also affect the texture. Outside the above range, Δr described later deviates from the range defined in the present invention. Therefore, the Mg content is 0.30 to 0.80%. The Mg content is preferably 0.40 to 0.80%.

Si:
Si contributes to strength improvement in cooperation with Mg. In addition, Si is produced as a crystallized product of metal Si during casting, and the periphery of the metal Si particles is deformed by processing and becomes a recrystallization nucleus generation site during solution treatment. Also contributes. If the Si content is less than 0.80%, the above effect cannot be obtained sufficiently. On the other hand, when the Si content exceeds 1.40%, a large number of intermetallic compounds are generated, which causes a decrease in press formability, particularly bending workability. Further, the solid solution of Si and the formation of intermetallic compounds due to the addition of Si also affect the texture. Outside the above range, Δr described later deviates from the range defined by the present invention. Therefore, the Si content is 0.80 to 1.40%. The Si content is preferably 0.80 to 1.20%.

Mn:
Mn is an element that exhibits an effect of improving strength, refining crystal grains, and stabilizing the structure. When the Mn content is 0.20% or more, the above effects can be sufficiently obtained. Moreover, by making Mn content 0.65% or less, the above-mentioned effects can be sufficiently maintained, and adverse effects on formability, particularly bending workability due to the generation of a large number of intermetallic compounds can be suppressed. . Furthermore, the formation of the intermetallic compound by addition of Mn also affects the texture. By setting the Mn content within the above range, Δr described later can be within the range defined by the present invention. Therefore, the Mn content is set to 0.20 to 0.65%. The Mn content is preferably 0.30 to 0.60%.

Zn:
Zn is an element that contributes to strength improvement through aging improvement and is effective in improving surface treatment. By making the Zn content 0.44% or more, the above effects can be sufficiently obtained. Moreover, the fall of a moldability can be suppressed because Zn content shall be 0.60% or less. Furthermore, the solid solution of Zn due to the addition of Zn also affects the texture. By setting the Zn content within the above range, Δr described later can be within the range defined by the present invention. Therefore, the Zn content is set to 0.44 to 0.60%.

Fe:
Fe is an element effective for strength improvement and crystal grain refinement. When the Fe content is 0.25% or more, the above effect can be sufficiently obtained. Moreover, the fall of press formability and bending workability by the production | generation of many intermetallic compounds can be suppressed because Fe content shall be 0.40% or less. Furthermore, the solid solution of Fe and the formation of intermetallic compounds due to the addition of Fe also affect the texture. By setting the Fe content within the above range, Δr described later is within the range specified in the present invention. Can do. Therefore, the Fe content is 0.25 to 0.40%. The Fe content is preferably 0.25 to 0.35%.

Cu:
Cu is an element effective for improving strength and improving formability. If the Cu content is less than 0.17%, the above effects cannot be obtained sufficiently. On the other hand, if the Cu content exceeds 0.25%, the bendability is impaired. Further, Cu solid solution and formation of intermetallic compounds due to addition of Cu also affect the texture. By setting the Cu content within the above range, Δr described later may be within the range specified in the present invention. it can. Therefore, the Cu content is 0.17 to 0.25%.

  Moreover, you may add 1 or more types selected from Cr, Zr, and V for the purpose of strength improvement, refinement | miniaturization of a crystal grain, and stabilization of a structure | tissue. Each content of Cr, Zr, and V is preferably 0.01 to 0.40%. By making each of these contents 0.01% or more, the above effects can be sufficiently obtained. In addition, by making each of these contents 0.40% or less, it is possible to suppress the adverse effects on formability, particularly bending workability due to the generation of a large number of intermetallic compounds, while maintaining the above effects sufficiently. it can. Therefore, each of these contents is preferably 0.01 to 0.40%, and more preferably 0.01 to 0.20%.

  Furthermore, Ti may be added for the purpose of improving the strength of the final plate, preventing rough skin, and improving ridging resistance through refinement of the ingot structure. The Ti content is preferably 0.005 to 0.300%. By making the Ti content 0.005% or more, the above effects can be sufficiently obtained. Moreover, the production | generation of a coarse crystallization thing can be suppressed, maintaining said effect fully by making Ti content 0.300% or less. Therefore, the Ti content is preferably 0.005 to 0.300%, and more preferably 0.005 to 0.100%. In addition, B may be added together with Ti, whereby the effect of refining and stabilizing the ingot structure becomes more remarkable. The content of B in the case of adding B together with the Ti content is 1 to 500 ppm, preferably 1 to 200 ppm. If it is less than 1 ppm, the above-mentioned remarkable effect cannot be obtained, and if it exceeds 500 ppm, a coarse crystallized product is formed.

  Further, a trace amount of one or more of Ag, In, Cd, Be and Sn which are high temperature aging promoting elements or room temperature aging suppressing elements may be added. In that case, if each content of these elements is 0.3% or less, or 1.0% or less as a whole, other characteristics are not impaired. Further, a small amount of Sc may be added to refine the ingot structure. In that case, if the Sc content is 0.01 to 0.20%, the effect of the present invention is not impaired. In addition to the elements listed above, Ni, Bi, or the like may be contained as impurities, respectively, at 0.05% or less, and as a whole, 0.15% or less.

2. Relation of content in aluminum alloy Next, the relation of content in the aluminum alloy will be described based on the following formulas (1) to (3).
CSi + CFe + CMn ≦ 2.30 (1)
When CSi / CMg <1.60,
{1.60− (CSi / CMg)} / (CMg ² + CFe + CMn) ≦ 1.90 (2)
When CSi / CMg ≧ 1.60,
{0.1 / (CMg ² )} + CFe + CMn) ≦ 1.70 (3)
Here, CSi, CFe, CMn, and CMg indicate the contents of Si, Fe, Mn, and Mg in the aluminum alloy, respectively.

  First, equation (1) is an equation defined from the viewpoint of ensuring good bending workability. Si, Fe, and Mn are elements that particularly contribute to the formation of coarse intermetallic compounds, and an upper limit is set for each of the additive elements described above, but the sum of the three elements must also be regulated. By setting the total sum of the three parties to 2.3 (%) or less, for example, good bending workability suitable for use in an automobile body panel or the like is ensured. Formula (1) is obtained from an experimental relationship between the sum of the contents of Si, Fe and Mn and bending workability.

  Next, formulas (2) and (3) are formulas defined from the viewpoint of securing the yield strength after the coating baking process. Si and Mg are elements that contribute to a significant improvement in strength by precipitation during paint baking, but easily form intermetallic compounds with Fe and Mn. As a result, Si and Mg that contribute to the strength improvement are consumed for the formation of the intermetallic compound, so that the strength improvement effect decreases with the addition of Fe and Mn. The formula (2) defines the case where the ratio of the Si content to the Mg content in the aluminum alloy is less than 1.60, and the formula (3) is the ratio of the Si content to the Mg content in the aluminum alloy. 1. Specify the case of 60 or more. While satisfying each element range mentioned above, and addition amount of Si, Mg, Fe, and Mn satisfies the above formulas (2) and (3), for example, after paint baking suitable for use in automobile body panels and the like Yield strength can be obtained. Here, the formulas (2) and (3) are divided into cases of CSi / CMg as described above, and in the experiments of the content of Si, Mg, Fe and Mn and good post-baking strength in each case. The obtained relationship is obtained by numerical analysis.

3. Next, the manufacturing method of the aluminum alloy plate for shaping | molding which concerns on this invention is demonstrated.

  First, an ingot is produced by melting an aluminum alloy having the above alloy composition in accordance with a conventional method and casting a molten metal. The obtained ingot is subjected to homogenization treatment, hot rolling, intermediate annealing, cold rolling, solution treatment, and stabilization treatment in this order. The preferable conditions for each step for satisfying the material properties defined in the present invention will be described below.

Casting process:
In the casting process, the molten metal is cast by a normal casting method such as a DC casting method to obtain an ingot.

Homogenization process:
The main purpose of the homogenization treatment is to eliminate segregation of additive elements. The homogenization temperature is preferably 480 ° C. or higher and lower than the melting point. If the temperature of the homogenization treatment is less than 480 ° C., the effect of eliminating segregation cannot be obtained sufficiently. On the other hand, eutectic melting occurs when the treatment temperature is higher than the melting point. Although the time for the homogenization treatment depends on the amount of added elements, it is preferably 20 minutes to 24 hours within the above temperature range. If the treatment time is less than 20 minutes, it may be difficult to sufficiently eliminate segregation. On the other hand, when the processing time exceeds 24 hours, the manufacturing cost increases.

Hot rolling process:
In the subsequent hot rolling step, the starting temperature is preferably 450 to less than the melting point. When the starting temperature is less than 450 ° C., deformation resistance increases and production efficiency decreases. On the other hand, eutectic melting occurs when the starting temperature is equal to or higher than the melting point. Moreover, it is preferable that the completion | finish temperature of hot rolling shall be 200-400 degreeC. If the end temperature is less than 200 ° C., the deformation resistance increases and the production efficiency decreases. On the other hand, when the end temperature exceeds 400 ° C., the precipitates become coarse and it becomes difficult to form a solution in the subsequent steps.

Intermediate annealing process:
The subsequent intermediate annealing is aimed at solution and recrystallization of the additive elements. The holding temperature of the intermediate annealing is preferably 480 ° C. or higher and lower than the melting point. This step is important for dissolving Mg ₂ Si, elemental Si and the like in the matrix, thereby imparting bake hardenability and improving the strength after paint baking. Furthermore, this process, Mg 2 _Si, the solid solution such as elemental Si particles by lowering the distribution density of the second phase particles, which contributes to the improvement of ductility and bendability. Furthermore, this step is important for obtaining a desired crystal structure and obtaining good formability together with the subsequent cold rolling step and solution treatment step.

If the holding temperature of the intermediate annealing is less than 480 ° C., the above effects may not be sufficiently obtained. On the other hand, if the processing temperature is higher than the melting point, eutectic melting may occur. The holding time for the intermediate annealing is preferably 5 minutes or less. When the holding time exceeds 5 minutes, productivity is lacking. Also, in order to prevent a large amount of Mg ₂ Si, elemental Si, etc. from precipitating at the grain boundaries during the cooling of the intermediate annealing, cooling from the holding temperature to a temperature range of 150 ° C. or less at a cooling rate of 100 ° C./min or more (Quenching) is preferable. In addition, you may provide a cold rolling process as needed between this intermediate annealing process and the hot rolling which is the previous process.

Cold rolling process:
In the subsequent cold rolling process, the hot-rolled sheet is rolled by a conventional method to a desired sheet thickness. By increasing the cold rolling rate, the crystal grain size is refined, and the effect of improving the bendability and preventing rough skin is exhibited. Therefore, the cold rolling rate is preferably 25% or more. From the viewpoint of controlling the metal structure, there is no positive reason to limit the upper limit of the cold rolling rate. However, when the cold rolling rate is excessively increased, the productivity is reduced and the cold rolling rate is 90%. The following is preferable. In order to stably obtain a crystal structure having a desired Δr, which will be described later, it is desirable to set the cold rolling rate within the above range.

Solution treatment process:
After the cold rolling is completed, the cold rolled sheet is subjected to a solution treatment. The purpose of the solution treatment is the same as in the intermediate annealing, and is in the solid solution and recrystallization of the additive elements. The final crystal structure is determined by recrystallization during the solution treatment. The solution treatment temperature is 480 ° C. or higher, preferably 490 ° C. or higher and lower than the melting point. When the solution treatment temperature is less than 480 ° C., it is advantageous for suppressing the aging of the room temperature aging, but the amount of solid solution decreases and sufficient bake hardenability cannot be obtained, and ductility and bendability are also obtained. Remarkably worse. On the other hand, in order to suppress the occurrence of eutectic melting during solution treatment, the melting point is set to less than the melting point. Moreover, it is preferable that the retention time of the solution treatment is 5 minutes or less. When the holding time exceeds 5 minutes, the productivity is lowered. Furthermore, in order to prevent a large amount of Mg ₂ Si, elemental Si, etc. from precipitating at the grain boundaries during cooling after holding the solution treatment, at a cooling rate of 100 ° C./min or higher, the holding temperature is 150 ° C. or lower. Cooling (quenching) to a temperature range is preferable. In addition, the retention time of 0 seconds in the solution treatment in the examples described later means that the solution is cooled immediately after reaching the solution treatment temperature.

Stabilization process:
Within 1 hour after the completion of the solution treatment step, it is necessary to perform a stabilization treatment in which the rolled plate is heated and held at a temperature of 80 to 120 ° C. for 1 hour or more. This stabilization treatment contributes to the improvement of strength during paint baking. P. The purpose is to form an atomic group called cluster II that easily migrates to the zone, and is a treatment necessary for securing the strength after paint baking. When the temperature is kept below 80 ° C. for more than 1 hour after the solution treatment process is completed, cluster I is formed which competes with cluster II and prevents strength improvement during paint baking. Insufficient strength. On the other hand, when the heating and holding temperature exceeds 120 ° C., the cluster II grows excessively and bending workability and formability deteriorate. Furthermore, when the heating and holding time is less than 1 hour, the formation of the cluster II is insufficient and the strength after baking is insufficient. The upper limit of the heating and holding time is not particularly limited, but is preferably within 24 hours from the viewpoint of production efficiency.

4). Δr
Next, Δr in the aluminum alloy will be described based on the following equations (4) and (5).
−0.50 ≦ Δr ≦ −0.01 (4)
Δr = 1/2 (r0 ° + r90 ° -2 × r45 °) (5)
Here, r0 ° is a Rankford value (r value) parallel to the rolling direction of the aluminum alloy plate, r90 ° is an r value perpendicular to the rolling direction of the aluminum alloy plate, and r45 ° is the aluminum alloy plate. The r value in the direction rotated 45 ° from the rolling direction is shown.

  The r value is the ratio between the logarithmic strain in the plate width direction and the logarithmic strain in the plate thickness direction when a predetermined amount, for example, 15% of tensile deformation is applied to the tensile test piece, that is, r = (logarithmic strain in the plate width direction). ) / (Logarithmic strain in the thickness direction). Δr is an index indicating the anisotropy of the r value.

  The main orientation of the aluminum alloy is the Cube orientation {001} <100>, and when the Cube orientation develops, the value of r45 ° tends to be lower than r0 ° and r90 °. As a result, as can be seen from the above equation (5), it is common for Δr to be a positive value in an aluminum alloy. According to the present invention, as described above, by limiting the alloy composition and the manufacturing method, it is possible to stably obtain a crystal structure having a different aspect from that in which Δr is not a positive value. Thus, by making Δr within the range defined by the present invention, an improvement effect of formability can be obtained, and one of the features of the present invention is to offset a decrease in formability due to an increase in impurity elements.

  For example, in an aluminum alloy plate for an automobile body panel, a technique for improving formability by improving the r value is already known, but by strictly defining the alloy composition and the manufacturing process, for example, the r value can be controlled. An aluminum alloy sheet having a crystal structure in which Δr has a negative value (not an increase in r value) can be obtained without performing special plastic working such as effective different speed rolling, and the effect of improving formability can be obtained. This is what the present inventors have found for the first time.

5. Strength after Paint Baking For example, in an automobile body panel, the strength is improved by precipitation hardening during the paint baking process after molding. Although it depends on the conditions of paint baking, the strength improvement effect is greatest at the beginning of time and tends to decrease with time. In the present invention, assuming a general use with an aluminum plate for an automobile body panel, the proof stress after the coating baking process is defined as 200 MPa or more 100 days after the solution heat treatment. Satisfying this condition provides a material that can withstand production on an actual industrial scale. In the present invention, by limiting the alloy composition and controlling the solution treatment and the stabilization treatment among the manufacturing methods, the characteristics of the proof stress after the paint baking treatment are ensured. In the present invention, holding at 180 ° C. for 1 hour was set as a coating baking condition.

6). Tensile strength-proof strength Tensile strength-proof strength, that is, the value obtained by subtracting the proof strength from the tensile strength is used as one of the indicators of formability. Improved. In the present invention, this tensile strength-proof strength is specified to be 110 MPa or more. The tensile strength-proof strength is more preferably 120 MPa or more. In the present invention, it is ensured that the value obtained by subtracting the yield strength from the tensile strength is 110 MPa or more by limiting the alloy composition and controlling the solution treatment conditions among the manufacturing methods.

  Examples of the present invention will be described below. The following examples are for explaining the effects of the present invention, and the processes and conditions described in the examples do not limit the technical scope of the present invention.

  First, alloys A1 to A6 within the component composition range of the present invention shown in Table 1 and B1 to B6 outside the component composition range of the present invention were respectively melted in accordance with a conventional method and cast into a slab by a DC casting method.

  Each slab obtained was homogenized at 540 ° C. for 10 hours, cooled to room temperature, reheated, hot-rolled at a start temperature of 530 ° C. and an end temperature of 250 ° C., and rolled to a thickness of 3 mm. I got a plate. The obtained hot-rolled sheet was cold-rolled to a thickness of 2 mm. Next, the cold-rolled sheet was subjected to intermediate annealing by being held at 530 ° C. for 5 seconds in a salt bath furnace, and forcibly air-cooled from the holding temperature to room temperature at a cooling rate of 300 ° C./min using a fan. Subsequently, after the sheet thickness was 1 mm by cold rolling, solution treatment was performed, and then forced air cooling was performed from the solution treatment temperature to room temperature using a fan at a cooling rate of 300 ° C./min. Next, the final plate was obtained by subjecting the forced air-cooled rolled plate to a stabilization treatment. The solution treatment and the stabilization treatment were performed under the conditions shown in Table 2.

  Each characteristic was evaluated by the method shown below about Invention Examples 1-11 which are in the range prescribed | regulated by this invention among the obtained aluminum alloy final plates, and Comparative Examples 12-23 outside the range prescribed | regulated by this invention. . The evaluation results are also shown in Table 2. Table 2 also shows the calculation results of the left side of the above-described equations (1) to (3) and the Si / Mg values related to the equations (2) and (3).

Yield strength after coating baking treatment 100 days after solution treatment (100 days after BHYS):
The final plate produced as described above was allowed to age for 100 days at room temperature, and then a JIS No. 5 test piece in the 90 ° direction with respect to the rolling direction was collected and subjected to heat treatment simulating paint baking at 180 ° C. for 1 hour. It was. After this heat treatment, a room temperature tensile test based on JISZ2241 was performed to measure the yield strength after the paint baking process.

<Tensile strength-yield strength> after 100 days of solution treatment (TS-YS after 100 days)
After the final plate produced as described above was aged at room temperature for 100 days, a JIS No. 5 test piece in a direction of 90 ° with respect to the rolling direction was collected, and a room temperature tensile test based on JISZ2241 was performed to obtain a tensile strength (TS). The yield strength (YS) was measured and the difference was determined.

Δr:
From the final plate produced as described above, JIS No. 5 test specimens were collected from three directions of 0 °, 45 °, and 90 ° with respect to the rolling direction, and the elongation and width displacement were obtained when the nominal strain was 0% and 15%. After measuring each r value in three directions, Δr was determined according to the equation (5).

Formability (press formability):
The overhang height and the limit drawing ratio were measured as evaluation of formability as press formability.
The overhang height is determined by applying No. 1 made by Castrol as a lubricant after pasting a resin film (SPV-224) made by Nitto Denko Corporation on the final plate produced as described above. 700 was applied, and a φ100 mm ball head overhang test was performed under the condition of a wrinkle holding force of 15 ton. The case where the overhang height was 34 mm or more was regarded as acceptable, and the case where it was less than 34 mm was regarded as unacceptable.
The limit drawing ratio was determined by converting the final plate produced as described above into a disc having a diameter of 60 to 70 mm, and then using Castrol No. as a lubricant. 700 was applied, and a squeezing test was conducted with a φ32 mm punch under the condition of a wrinkle holding force of 150 kg. The limit drawing ratio was determined as “maximum sample diameter that could be drawn” / “ratio of punch diameter”. The case where the limit drawing ratio was 1.95 or more was determined to be acceptable, and the value of less than 1.95 was regarded as unacceptable.

Flexibility:
The final plate produced as described above was aged at room temperature for 100 days, and then a JIS No. 5 test piece with a direction of 90 ° with respect to the rolling direction was collected, and a hemming test based on JIS 7701 : 2008 was performed. The pre-strain was 8%, the punch tip radius during pre-hemming was 0.5 mm, and the thickness of the intermediate plate during main hemming was 1.0 mm. After hemming test was performed to observe the outer periphery surface, JISH7701 at the outer peripheral portion surface: those score 0-2 points defined by criteria of 2008 as acceptable (○), unacceptable ones 3-4 points (X) was determined.

  In Invention Examples 1 to 11 in which the alloy composition and the production conditions are within the range defined in the present invention, the alloy composition containing a large amount of impurity elements, the coating baking process was performed 100 days after the solution treatment. The yield strength and the value of “tensile strength-proof strength” 100 days after solution treatment are high, Δr is negative, the overhang height / limit drawing ratio is high, and the bendability is also good. It was suitable for materials such as body sheets and body panels, such as press molding, paint bake hardening, and members / parts to be bent.

  On the other hand, in Comparative Examples 12 to 23 which are outside the range specified in the present invention, the proof stress when the coating baking process was performed 100 days after the solution treatment, and the “tensile strength-proof strength 100 days after the solution treatment. “At least one of the overhang height and the limit drawing ratio is poor, and the high material properties required for, for example, an automobile body panel cannot be secured.

  Specifically, in Comparative Example 12, since the solution treatment temperature was low, BHYS after 100 days, TS-YS after 100 days, and formability (hereinafter referred to as “press formability”) were unacceptable.

  In Comparative Example 13, BHYS was rejected after 100 days because the time from the solution treatment to the start of the stabilization treatment was long.

  In Comparative Example 14, since the holding time of the stabilization treatment was short, BHYS was rejected after 100 days.

  In Comparative Example 15, since the temperature of the stabilization treatment was high, press formability and bendability were unacceptable.

  In Comparative Examples 16 and 17, the relationship between Si, Mg, Fe, and Mn in the aluminum alloy composition did not satisfy the formula (2), so BHYS after 100 days and TS-YS after 100 days failed.

  In Comparative Example 18, the BHYS was rejected after 100 days because the relationship among Mg, Fe, and Mn did not satisfy the formula (3) in the aluminum alloy composition.

  In Comparative Example 19, the bendability was rejected because the relationship among Si, Fe, and Mn did not satisfy the formula (1) in the aluminum alloy composition.

  In Comparative Examples 20 and 21, in the aluminum alloy composition, Si, Fe, Cu, Zn deviated from the range defined in the present invention, and therefore, the expression (4) according to the expression (5) was not satisfied, and TS-YS after 100 days, press formability The bendability was unacceptable.

  In Comparative Example 22, in the aluminum alloy composition, Si, Mg, Mn, and Zn deviated from the ranges defined in the present invention, so the expressions (3) and (4) were not satisfied, and BHYS after 100 days, TS-YS after 100 days, press Formability and bendability were unacceptable.

  In Comparative Example 23, Mg, Mn, Fe, and Cu in the aluminum alloy composition deviated from the range specified in the present invention, so that the formula (4) was not satisfied, and press formability and bendability were unacceptable.

  The aluminum alloy sheet for forming according to the present invention is excellent in press formability, paint bake hardenability, bendability and recyclability, and is suitable as a material for various automobile members and parts such as automobile body sheets and body panels. Can be used.

Claims (2)

Mg: 0.30 to 0.80 mass%, Si: 0.80 to 1.40 mass%, Mn: 0.20 to 0.65 mass%, Zn: 0.44 to 0.60 mass%, Fe: 0.25 0.40%, Cu: with containing 0.17～0.25Mass% satisfies the following (1) to (3), made of aluminum alloy and the balance Al and impurities, rank Ford value (r value) Δr which shows the anisotropy of the following satisfies the following formulas (4) and (5), the proof stress after the coating baking treatment is 200 MPa or more after 3 months of the solution treatment, and the proof strength from the tensile strength: minus the the Ri der least 110MPa, JISH7701: press formability score defined by criteria of hemming tests based on 2008 and wherein 0-2 Tendea Rukoto, painting Give curable, bendability and recycling excellent in molding an aluminum alloy plate.
CSi + CFe + CMn ≦ 2.30 (1)
When CSi / CMg <1.60,
{1.60− (CSi / CMg)} / (CMg ² ) + CFe + CM n ≦ 1.90 (2)
When CSi / CMg ≧ 1.60,
{0.1 / (CMg ² )} + CFe + CM n ≦ 1.70 (3)
−0.50 ≦ Δr ≦ −0.01 (4)
Δr = 1/2 (r0 ° + r90 ° -2 × r45 °) (5)
Here, CSi, CFe, CMn, and CMg indicate the contents of Si, Fe, Mn, and Mg, respectively, r0 ° is an r value in a direction parallel to the rolling direction of the aluminum alloy plate, and r90 ° is an aluminum alloy plate. The r value in the direction perpendicular to the rolling direction, r45 °, indicates the r value in the direction rotated 45 ° from the rolling direction of the aluminum alloy sheet. It is a manufacturing method of the aluminum alloy plate for shaping | molding of Claim 1, Comprising: The casting process which casts the said aluminum alloy, the homogenization process process which homogenizes an ingot, and heats the ingot which homogenized process A hot rolling step for hot rolling, an intermediate annealing step for the hot rolled plate, a cold rolling step for cold rolling the intermediate annealed rolled plate, a solution treatment step for solution treating the cold rolled plate, A stabilization treatment step of stabilizing the solution-treated rolled sheet, wherein the temperature of the solution treatment is 480 ° C. or higher and lower than the melting point of the aluminum alloy, and the stabilization treatment step is the solution treatment step Within 1 hour after the completion of the process, the rolled plate is heated and held at a temperature of 80 to 120 ° C. for 1 hour or longer, and is excellent in press formability, paint bake hardenability, bendability and recyclability. Alloy plate Production method.