JP3734317B2 - Method for producing Al-Mg-Si alloy plate - Google Patents

Description

【００２５】
【表２】

【００２６】
このように製造された板材について、板の金属組織における最大結晶粒径を光学顕微鏡で測定した。また、表層部の連続したMg₂Si 化合物の最大長さを、走査型電子顕微鏡を用いて反射電子像の観察を行って、測定した。
また、製造後1、5、20、60 日間、室温に放置した後、引張試験を実施した。さらに塗装・焼付け加熱をシミュレートした 175℃で60分の加熱を施した後にも引張試験をおこなった。引張試験はJIS5号引張試験片により、引張強さ、耐力、伸びを測定した。これらの結果を表３に示す。
【００２７】
【表３】

【００２８】
表３より明らかなように、本発明の圧延板及びその製造方法(A-G) では、
塗装・焼付けの際の加熱による耐力上昇が大きく（100MPa以上）、加熱前の延性（伸び）も優れ（27% 以上）、さらにこれらの特性の室温放置による安定性に優れていることがわかる。
これに対して、本発明で規定した組成をはずれるか又は本発明の製造条件を外れる比較例(H-N) は、加熱前後の耐力上昇が小さく、または加熱前の延性（伸び）の点でも劣っていることがわかる。
【００２９】
【発明の効果】
このように本発明に係わるAl-Mg-Si系合金板の製造方法によれば、自然時効時のG.P.ゾーンの析出を抑制し、塗装・焼付けの際の加熱で速やかに強化相が析出し、経時変化が小さく高い時効硬化性を有するAl-Mg-Si系合金板を低コストで得ることができるもので、工業上顕著な効果を奏するものである。
【図面の簡単な説明】
【図１】 横型双ロールによる直接鋳造圧延装置（断面）の概略説明図である。
【図２】 図１のＤ部を拡大した詳細図である。
【符号の説明】
１ 上ロール
２ 下ロール
３ ノズル
４ 金属溶湯
５ 直接鋳造圧延板
Ａ 双ロールのセンターライン（ロールの最接近点）
Ｂ ノズルの先端
Ｃ 溶湯の最終凝固点[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing an Al-Mg-Si based alloy sheet having little bake hardenability with little change over time, and more specifically used for bending molding, press molding, etc. of automobile parts, home appliances, etc. The present invention relates to a production method capable of producing a rolled sheet of an Al—Mg—Si alloy suitable for forming at a low production cost by direct casting and cold rolling as compared with the prior art.
In the present specification, the content of the additive element of the Al alloy means mass%, but this is simply indicated as%.
[0002]
[Prior art]
For automotive outer panels, home appliance chassis, etc., Al-Mg-Si alloy plates that are excellent in corrosion resistance and ductility and age-harden by heating are formed into a predetermined shape, and then aged by painting and baking and heating. It is often cured to produce a product.
However, the Al-Mg-Si alloy plate manufactured by the conventional manufacturing method is left at room temperature after solution treatment (natural aging), and the GP zone precipitates, which contributes to strength improvement during baking and heating. This prevents the precipitation of the Mg ₂ Si intermediate phase or the strengthening phase equivalent to it, so that a material that has passed for a long time after the solution treatment has sufficient strength after painting and baking. There wasn't. Furthermore, the strength increases with the precipitation of the GP zone, and the problem that the ductility is remarkably lowered has occurred at the same time.
[0003]
As a method for solving this problem, preliminary aging treatment after solution treatment as shown in Japanese Patent Publication No. 05-7460, restoration treatment as shown in Japanese Patent Application Laid-Open No. 04-259358, or a combination thereof. Processing has been devised. However, these treatments can increase the strength at the time of painting and baking without impairing the ductility, but there is a problem that the manufacturing cost increases due to an increase in the number of steps.
Conventional Al-Mg-Si alloy rolled sheets for forming and formed articles thereof are manufactured as follows, including the above-described improved manufacturing method.
That is, these are produced by first producing an ingot of a predetermined alloy composition, chamfering and homogenizing this, followed by hot rolling, cold rolling (annealing as necessary), solution treatment, Manufactured by preliminary aging treatment or restoration treatment, molding, age hardening treatment (painting / baking heating).
As described above, the conventional manufacturing method has a very long process and requires a large facility, so that the manufacturing cost is high and it is not necessarily suitable for industrial production.
[0004]
[Problems to be solved by the invention]
The object of the present invention is to suppress the GP zone that precipitates during natural aging due to standing at room temperature, and the molding Al- It is to provide a production method combining a direct casting rolling method and a conventional cold rolling method capable of producing an Mg—Si based alloy sheet at a low cost due to an extremely short process.
Another object of the present invention is to find preferred production conditions in the production method .
In addition, as shown in FIGS. 1 and 2, the direct casting and rolling method referred to here is a method in which the molten metal 4 is continuously supplied from the nozzle 3 between the twin rolls 1 and 2 and immediately after the casting of the molten metal is solidified. It rolls with rolls 1 and 2 to make a long rolled plate and its coil directly from the molten metal. Unlike the method of obtaining only a continuous cast plate, this method is generally called a hunter method, a direct rolling method, or the like, but in this specification, it is referred to as a direct casting and rolling method.
This manufacturing method is an ingot or cast plate process that is conventionally performed in separate processes, a homogenization process, a hot and cold rolling process, etc. are performed in a single process, and many processes can be omitted. There is.
[0005]
[Means for Solving the Problems]
The method for producing an Al—Mg—Si based alloy plate according to the present invention is configured as follows in order to solve the above problems.
That is, the manufacturing method according to claim 1 includes Si 0.2 to 3.0% (mass% , the same shall apply hereinafter ) , Mg 0.2 to 3.0%, Ti 0.001 to 0.5% as essential elements, and Cu 0 to 2.5% (however, , 0 % means the case where it does not contain. The same applies hereinafter.) Sn 0 to 0.2% , Zn 0 to 2.0% , or one or more of them, Fe is regulated to 1.0% or less, and the balance is Al. An Al alloy melt consisting of inevitable impurities is directly cast and rolled into a plate with a thickness of 4mm or less using a direct casting and rolling machine with twin rolls under the condition that the rolling load P (ton) satisfies the following formula. then the plate was cold-rolled at a rolling reduction of less than 15% 70%, followed by subjected to solution treatment in the range of the melting temperature of 400 ° C. ~ material, 2 ° C. / s or more as a cooling after the solution quenched to 175 ° C. or less at a cooling rate, then 180 to 320 ° C. following or the reheating reheating held below 25 minutes in the temperature, the plate metal structure Maximum crystal grain size of 100 [mu] m or less, and the maximum length of consecutive Mg ₂ Si compounds of the surface layer portion, characterized in that the 50μm or less.
1: P ≧ 5.8 × 10 ^-6 · t · w · D ^1/2 · v · exp {1600 / (T + 273)} · (R / 100) ^-0.5
However,
t: Outlet plate thickness (mm), w: Outlet plate width (mm), D: Roll diameter (mm),
v: Roll peripheral speed (mpm), T: Outlet plate surface temperature (° C), R: Cold rolling rate (%)
[0006]
The manufacturing method according to claim 2 is an alloy melt having the same composition as that of the Al alloy molten metal according to the manufacturing method according to claim 1 and having a thickness of 4 mm or less under the same method and conditions as in the manufacturing method according to claim 1 . Casting and rolling directly onto the plate, and then cold rolling the plate at a rolling rate of 15% or more and less than 70%, followed by solution treatment in the range of 400 ° C to the melting temperature of the material, cooling after solution treatment as rapidly cooled to a range of forty to one hundred and seventy-five ° C. at 2 ° C. / s or more cooling rate, wound in a coil shape at the temperature, the maximum grain size of the metal structure of the plate 100 [mu] m or less, and and continuous surface layer portion The maximum length of the Mg ₂ Si compound is 50 μm or less.
[0007]
In the manufacturing method according to claim 3, the molten alloy having the same composition as the molten Al alloy in the manufacturing method according to claim 1 is used, and the rolling load P (ton) is set to 2 Directly cast and rolled into a plate with a thickness of 4 mm or less under conditions that satisfy the equation, and then cold-roll the plate at a rolling rate of 70% or more, followed by solution treatment in the range of 400 ° C to the melting temperature of the material. performs processing, and rapidly cooled to below 175 ° C. at 2 ° C. / s or more cooling rate of cooling after solution treatment, followed 180 to 320 ° C. to following or the reheating reheating than 25 minutes in the temperature holding and, characterized in that the 100 [mu] m maximum grain size of the metal structure of the plate below, and the maximum length of consecutive Mg ₂ Si compounds of the surface layer portion is 50μm or less.
2: P ≧ 2.9 × 10 ^-6 · t · w · D ^1/2 · v · exp {1600 / (T + 273)} · (R / 100) ^-0.5
However,
t: Outlet plate thickness (mm), w: Outlet plate width (mm), D: Roll diameter (mm),
v: Roll peripheral speed (mpm), T: Outlet plate surface temperature (° C), R: Cold rolling rate (%)
[0008]
According to a fourth aspect of the present invention, there is provided a molten alloy having the same composition as that of the molten Al alloy in the third method, and having a thickness of 4 mm or less under the same method and conditions as in the third method. It is cast and rolled directly on a plate, and then the plate is cold-rolled at a rolling rate of 70% or more, followed by solution treatment in the range of 400 ° C. to the melting temperature of the material, and cooling at 2 ° C. after cooling. rapidly cooled to a range of 40 to 175 ° C. at a cooling rate of at least 10 s / s, wound into a coil at the above temperature, the maximum crystal grain size of the metallographic structure of the plate being 100 μm or less, and a continuous layer of Mg ₂ Si The maximum length of the compound is 50 μm or less.
[0009]
The manufacturing method according to claim 5 is an alloy plate obtained by winding an Al-Mg-Si based alloy plate manufactured by the manufacturing method according to claim 1 or 3 into a coil shape. About either the Al-Mg-Si type alloy plate manufactured by the manufacturing method, and the Al-Mg-Si type alloy plate manufactured by the manufacturing method according to claim 4, the temperature is 2 to 24 at a temperature of 580 ° C or lower. It is characterized by cold rolling after homogenization treatment with time retention .
[0010]
The manufacturing method according to claim 6 is the manufacturing method according to any one of claims 1 to 5, wherein the molten Al alloy is at least Mn 0.01 to 0.5% , Cr 0.01 to 0.5% , Zr 0.01 to 0.5% . One or more types are further included.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The method of the present invention will be described in detail below.
First, the reason why the composition of the Al alloy molten metal is limited as described above in the present invention will be described.
Si is precipitated as an intermediate phase of Mg ₂ Si called β ′ together with Mg during coating / baking heating or a strengthening phase equivalent thereto, thereby improving the strength. The reason why the amount of addition is limited to 0.2 to 3.0% is that if the amount is less than 0.2%, the effect is small, and if it exceeds 3.0%, the ductility after the solution treatment decreases.
Mg is dissolved in the matrix after solution treatment and contributes to the improvement of ductility. Further, as described above, it is precipitated as a strengthening phase together with Si during coating / baking heating to improve the strength. The reason why the amount of addition is limited to 0.2 to 3.0% is that if the amount is less than 0.2%, the effect is small, and if it exceeds 3.0%, the ductility after the solution treatment decreases.
As described above, Si and Mg precipitate as a strengthening phase during coating and baking and heating, improving the strength. If the abundance ratio of these two elements is different, the bake hardenability will also be different. If the weight ratio of Si and Mg is Si> 0.6Mg%, the excess Si will be added to the amount of Mg ₂ Si, resulting in better bake hardenability. .
In order to control the aging behavior at the time of coating and baking, even if a small amount of Ag, Cd or the like is added, the effect of the present invention is not impaired.
[0012]
Ti is added to refine crystal grains or improve matrix strength. The amount added is 0.001 to 0.5%, and if the amount is less than the lower limit, the effect is small, and if the amount exceeds the upper limit, the ductility after the solution treatment is lowered.
Moreover, Cu, Sn, and Zn are precipitated during coating and baking, and improve the strength. The addition of Sn also has the effect of improving the surface quality. The addition is one or more of Cu 0 to 2.5%, Sn 0 to 0.2%, and Zn 0 to 2.0% as necessary.
Here, 0% of each element means that it may not be added. In addition, in the case of addition, each element is limited to 2.5% or less, 0.2% or less, and 2.0% or less, because if it exceeds these, the corrosion resistance is lowered and the quenching sensitivity is increased. It is.
Fe is usually contained as an impurity of Al. However, Fe is easy to make a compound with Si, and if it exceeds 1.0%, it will hinder the strength improvement during heating during painting and baking.
Note that B or the like that is normally added as a refined material of the cast structure does not particularly impair the effects of the present invention as long as it is added in an amount of 0.1% or less.
[0013]
Mn, Cr, Zr is optionally added in order to respectively increase miniaturization or matrix strength of the crystal grains (Claim 6). The addition is one or more of Mn 0.01 to 0.5% , Cr 0.01 to 0.5% , Zr 0.01 to 0.5% as necessary.
If each is less than the lower limit, the effect is small, and if the upper limit is exceeded, the ductility after the solution treatment is lowered.
[0014]
The direct casting and rolling method in the method of the present invention will be specifically described with reference to the drawings. By using a direct casting and rolling apparatus using twin rolls as shown in FIG. 1 and FIG. Supplying continuously between the twin rolls 1 and 2 through the nozzle 3, casting and solidifying between the closest point A of the twin rolls 1 and 2 from the tip B of the nozzle 3, and rolling near the point A is there. In FIG. 2, point C is the final freezing point of the molten metal.
In the present invention, the directly cast and rolled plate thus manufactured is further subjected to cold rolling and solution treatment, and then rapidly cooled, and subsequently reheated ( Claims 1 and 3 ) or high-temperature coil winding ( Claim 2). , 4 ).
[0015]
The manufacturing method described above is characterized in that the processing necessary for controlling the metal structure of solidification in conventional DC casting and plastic working in hot rolling is realized by direct casting and rolling with a single twin roll. Therefore, it is very important to appropriately determine the conditions for direct casting and rolling with this twin roll.
According to the method of the present invention, in order to find such a condition, the relationship between the twin roll direct casting rolling condition and the metal structure and mechanical properties is energetically studied from the basic viewpoint, and as a result, the following Thus, it has been found that an Al—Mg—Si alloy plate having performance equivalent to that of the conventional method can be produced by defining the production conditions as described above .
[0016]
Manufacturing conditions in the manufacturing method according to claims 1 and 2, The rolling load P (ton) applied to the twin rolls is expressed by the following formula:
1: P ≧ 5.8 × 10 ^-6 · t · w · D ^1/2 · v · exp {1600 / (T + 273)} · (R / 100) ^-0.5
However,
t: Outlet plate thickness (mm), w: Outlet plate width (mm), D: Roll diameter (mm),
v: Roll peripheral speed (mpm), T: Outlet plate surface temperature (° C), R: Cold rolling rate (%)
After casting and rolling directly to a sheet with a thickness of 4 mm or less under conditions that satisfy the following conditions, cold rolling at 15% to less than 70%, followed by solution treatment in the range of 400 ° C to the melting temperature of the material to form a solution As the subsequent cooling , it is rapidly cooled to 175 ° C. or lower at a cooling rate of 2 ° C./s or higher .
Here, the reduction load P (ton) is set to the above-mentioned formula 1. With a reduction load smaller than this, the amount of plastic deformation from the end of solidification is insufficient, and the crystallization phase is not sufficiently divided, and is produced by the conventional method. This is because the elongation is reduced as compared to the case where the final cold rolling rate is smaller.
This conditional expression is for the case where the rolling reduction during the subsequent process is 15% or more and less than 70%.
In addition, although there is no restriction | limiting in particular about the cooling rate after direct casting rolling, in order to fully exhibit the effect of the subsequent solution treatment, it is desirable to cool at the fastest possible speed.
[0017]
The reason why the cold rolling rate was set to 15% or more is that if it is less than this, the structure generated during solidification is not sufficiently pulverized, resulting in a decrease in ductility, and the upper limit was set to less than 70%. This is because, in the case of a cold rolling ratio exceeding 70%, the conditional expression of the rolling load during direct casting and rolling is different from the above.
The solution treatment temperature was set to 400 ° C or higher in order to dissolve Mg and Si. Rapid cooling to a temperature of 175 ° C or lower at a cooling rate of 2 ° C / s or higher is the The primary purpose is to improve the strength by solid solution in supersaturation without causing precipitation of additive elements such as Si and Mg as much as possible, and by depositing a fine strengthening phase during subsequent coating and baking heating. However, a cooling rate of less than 2 ° C./s or cooling to a temperature of 175 ° C. or higher causes a coarse compound to precipitate during cooling, leading to a decrease in elongation.
[0018]
In the production method according to claims 1 and 2 of the present invention, after the solution treatment described above, it is rapidly cooled to 175 ° C. or less at a cooling rate of 2 ° C./s or more, and then reheated to 180 to 320 ° C. Hold for ˜25 minutes (Claim 1: Restoration treatment), or after the solution treatment described above, quench at a cooling rate of 2 ° C./s or more to a range of 40 to 175 ° C. and coil at that temperature Winding (Claim 2: High temperature coil winding) is required.
Although it is possible to produce a plate with the same performance as the plate obtained in the conventional process even by the above-mentioned process, the GP zone is precipitated by natural aging as in the conventional method. This is because there is a problem that the strength after heating is not sufficiently obtained, or the strength is increased and the moldability is remarkably lowered.
Also in the case of direct casting and rolling using twin rolls, it is necessary to suppress the GP zone generation due to natural aging by the above-described restoration treatment or high-temperature coil winding as in the conventional method.
[0019]
In the manufacturing method according to claim 1, after the solution treatment as described above, the solution is rapidly cooled to a temperature of 175 ° C. or lower and subsequently reheated (restored), which is reheated to 180 to 320 ° C. Holding is performed for 0 to 25 minutes, and then allowed to cool to room temperature.
Here, holding for 0 minutes means not to hold, that is, to cool without holding when the temperature reaches 180 to 320 ° C.
This reheating treatment is usually preferably carried out in a continuous annealing furnace (CAL).
In the manufacturing method of claim 2, after the solution treatment as described above, the coil is rapidly cooled to a temperature of 40 to 175 ° C., wound around the coil in this temperature range (high-temperature coil winding), and then left at room temperature. However, after the high-temperature coil is wound, the coil may be left at room temperature to cool, or it may be left in the furnace at the winding temperature (40 to 175 ° C). You may hold | maintain within 36 hours, and may cool after that. Further, after winding the high-temperature coil, the coil may be left at room temperature for a while, then kept in a furnace at 40 to 175 ° C. for 36 hours, and then allowed to cool.
For the treatment after the high-temperature winding, a conventionally known method for the Al—Mg—Si alloy material is applied as necessary.
The reason why there is a range in the heat treatment conditions of the restoration process and the high temperature coil winding process is that a predetermined performance cannot be obtained even if it is less than the lower limit or exceeds the upper limit.
Further, the room temperature standing time from the solution treatment to the rapid cooling to the restoration treatment need not be particularly limited, and the effect is not impaired even if the restoration treatment is carried out after standing for several months or more.
[0020]
Manufacturing conditions in the manufacturing method of Claim 3 and 4
The manufacturing method according to claims 2 and 3 is a case where the cold rolling ratio after direct casting and rolling exceeds 70%, and in this case, the rolling load P (ton) applied to the twin rolls is expressed by two formulas,
2: P ≧ 2.9 × 10 ^-6 · t · w · D ^1/2 · v · exp {1600 / (T + 273)} · (R / 100) ^-0.5
However,
t: Outlet plate thickness (mm), w: Outlet plate width (mm), D: Roll diameter (mm),
v: Roll peripheral speed (mpm), T: Outlet plate surface temperature (° C), R: Cold rolling rate (%)
And the conditions relating to the rolling load are changed as compared with the cases described in claims 1 and 2 .
This is because, when the cold rolling rate exceeds 70%, the crystallization phase is divided during cold rolling, so the rolling load during direct casting and rolling needs to be increased as in claims 1 and 2. Because there is no. Further, the smaller the final cold rolling rate, the larger the reduction is required, as in the case of claims 1 and 2 .
The conditions, meanings, effects, etc. of the solution treatment, cold cooling, restoration treatment ( Claim 3 ) or high-temperature coil winding ( Claim 4 ) after cold rolling are the same as those described in Claims 1 and 2 above. It is.
[0021]
About the manufacturing method of Claim 5 The invention of Claim 5 is the manufacturing method of Claims 1-4. It directly cast-rolls and winds up to a coil, This is homogenized, and cold rolling is implemented subsequently. Manufacturing method.
Such a homogenization treatment is performed for the purpose of eliminating solidification segregation of the directly cast and rolled plate and precipitation of dispersed phase particles containing a transition element, thereby improving ductility and strength.
This homogenization treatment condition was maintained at a temperature of 580 ° C. or lower for 2 to 24 hours in order to obtain the above-mentioned target characteristics.
[0022]
The Al-Mg-Si alloy sheet produced by the method of the present invention, the maximum crystal grain size in the metal structure of the rolled plate can be 100 [mu] m or less. If exceeding 100 [mu] m, sufficient ductility can not be obtained as a molding material, such as skin roughness occurs after molding, it is not preferred as a molding material.
Further, the surface layer portion of the metal structure of the rolled sheet, the maximum length of consecutive Mg ₂ Si compound is 50μm or less. If a coarse main solute compound containing Mg or Si whose maximum length exceeds 50 μm is already deposited before painting and baking, the amount of solid solution is insufficient. and strength improvement at the time of baking heat is no longer sufficient.
In addition, the plate | board thickness of the rolled sheet concerning this invention is about 0.7-3 mm.
The content of the Al-Mg-Si based alloy sheet produced by the production method according to the present invention is as described above. However, as is apparent from the examples described later, such a rolled sheet is before coating and baking and heating. Elongation is 27% or more, excellent moldability, and the strength (YS) is improved by 100 MPa or more in heating during painting and baking after molding, and molding materials for various applications as described above. Suitable for
As described above, according to the method of the present invention , it is possible to produce an Al—Mg—Si-based alloy plate having a small change with time and excellent in bake hardenability at low cost. Like conventional methods, restoration processing or high-temperature winding is required to suppress natural aging, but steps such as agglomeration, chamfering, homogenization, hot rolling and cold rolling up to the previous stage are required. Since it is greatly simplified, the total manufacturing cost is greatly reduced.
[0023]
【Example】
Next, examples of the present invention (examples of the present invention) will be described in detail together with comparative examples.
The molten Al-Mg-Si alloy having the composition shown in Table 1 is formed into a plate by a direct casting and rolling apparatus using a horizontal twin roll shown in FIGS. 1 and 2, and further cold-rolled to a thickness of 0.7 to 3 mm. The board material was manufactured. Details of the manufacturing conditions are shown in Table 2.
[0024]
[Table 1]

[0025]
[Table 2]

[0026]
With respect to the plate material thus manufactured, the maximum crystal grain size in the metal structure of the plate was measured with an optical microscope. Further, the maximum length of the Mg ₂ Si compound having a continuous surface layer was measured by observing the reflected electron image using a scanning electron microscope.
In addition, a tensile test was carried out after standing at room temperature for 1, 5, 20, 60 days after production. In addition, a tensile test was conducted after 60 minutes of heating at 175 ° C, which simulates painting and baking. In the tensile test, tensile strength, proof stress, and elongation were measured with a JIS No. 5 tensile test piece. These results are shown in Table 3.
[0027]
[Table 3]

[0028]
As is apparent from Table 3, in the rolled sheet and the manufacturing method (AG) of the present invention,
It can be seen that the increase in yield strength due to heating during painting and baking is large (100 MPa or more), the ductility (elongation) before heating is also excellent (27% or more), and the stability of these properties after standing at room temperature is also excellent.
On the other hand, Comparative Example (HN) that deviates from the composition defined in the present invention or deviates from the production conditions of the present invention has a small increase in yield strength before and after heating, or inferior in ductility (elongation) before heating. I understand that.
[0029]
【The invention's effect】
Thus , according to the method for producing an Al-Mg-Si alloy plate according to the present invention, the precipitation of the GP zone during natural aging is suppressed, and the strengthening phase is quickly precipitated by heating during painting and baking, An Al—Mg—Si-based alloy sheet having a small age change and high age-hardening properties can be obtained at low cost, and has a remarkable industrial effect.
[Brief description of the drawings]
FIG. 1 is a schematic explanatory diagram of a direct casting and rolling apparatus (cross section) using horizontal twin rolls.
FIG. 2 is an enlarged detail view of a portion D in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Upper roll 2 Lower roll 3 Nozzle 4 Molten metal 5 Direct cast rolling plate A Center line of a twin roll (nearest point of a roll)
B Nozzle tip C Final freezing point of molten metal

Claims (6)

Si 0.2-3.0% (mass%, the same shall apply hereinafter), Mg 0.2-3.0%, Ti 0.001-0.5% are included as essential elements, and Cu 0-2.5% (however, 0% is not included). The same)), Al alloy molten metal containing one or more of Sn 0-0.2%, Zn 0-2.0%, Fe regulated to 1.0% or less, the balance consisting of Al and inevitable impurities, twin rolls Using a direct casting and rolling device, the rolling load P (ton) is directly cast and rolled to a plate with a thickness of 4 mm or less under the conditions satisfying the following one set, and then the plate is 15% or more and less than 70%. Cold rolling at a rolling rate, followed by solution treatment in the range of 400 ° C to the melting temperature of the material, followed by rapid cooling to 175 ° C or less at a cooling rate of 2 ° C / s or more as cooling after solutionization, and then 180 Reheated to ~ 320 ° C or held at the temperature for 25 minutes or less following the reheating, the maximum grain size of the metallographic structure of the plate is 100 μm or less, and the continuous Mg ₂ Si in the surface layer part A method for producing an Al—Mg—Si based alloy sheet, wherein the maximum length of the compound is 50 μm or less.
1: P ≧ 5.8 × 10 ^-6 · t · w · D ^1/2 · v · exp {1600 / (T + 273)} · (R / 100) ^-0.5
However,
t: Outlet plate thickness (mm), w: Outlet plate width (mm), D: Roll diameter (mm),
v: Roll peripheral speed (mpm), T: Outlet plate surface temperature (° C), R: Cold rolling rate (%) Si 0.2-3.0%, Mg 0.2-3.0%, Ti 0.001-0.5% is contained as an essential element, and further Cu 0-2.5% (however, 0% means not included, the same applies hereinafter), Sn 0- Using direct casting and rolling equipment with twin rolls, Al alloy melt containing 0.2%, Zn 0-2.0% or more, Fe regulated to 1.0% or less, the balance consisting of Al and inevitable impurities Then, the rolling load P (ton) is directly cast and rolled on a plate having a thickness of 4 mm or less under the condition that satisfies the following one formula, and then the plate is cold-rolled at a rolling rate of 15% or more and less than 70%. Subsequently, solution treatment is performed in the range of 400 ° C to the melting temperature of the material, and after cooling, the solution is rapidly cooled to a range of 40 to 175 ° C at a cooling rate of 2 ° C / s or more, and coiled at the above temperature. The Al-Mg-Si is characterized in that the maximum crystal grain size of the metal structure of the sheet is 100 μm or less and the maximum length of the continuous Mg ₂ Si compound in the surface layer is 50 μm or less. Method for manufacturing an alloy plate.
1: P ≧ 5.8 × 10 ^-6 · t · w · D ^1/2 · v · exp {1600 / (T + 273)} · (R / 100) ^-0.5
However,
t: Outlet plate thickness (mm), w: Outlet plate width (mm), D: Roll diameter (mm),
v: Roll peripheral speed (mpm), T: Outlet plate surface temperature (° C), R: Cold rolling rate (%) Si 0.2-3.0%, Mg 0.2-3.0%, Ti 0.001-0.5% is contained as an essential element, and further Cu 0-2.5% (however, 0% means not included, the same applies hereinafter), Sn 0- Using direct casting and rolling equipment with twin rolls, Al alloy melt containing 0.2%, Zn 0-2.0% or more, Fe regulated to 1.0% or less, the balance consisting of Al and inevitable impurities Then, the rolling load P (ton) is directly cast and rolled on a plate having a thickness of 4 mm or less under the conditions satisfying the following two formulas, and then the plate is cold-rolled at a rolling rate of 70% or more, Solution treatment is performed in the range of 400 ° C to the melting temperature of the material, and after cooling, the solution is rapidly cooled to 175 ° C or less at a cooling rate of 2 ° C / s or more and then reheated to 180 to 320 ° C or Following reheating, the temperature is maintained for 25 minutes or less, the maximum grain size of the metallographic structure of the plate is 100 μm or less, and the maximum length of the continuous Mg ₂ Si compound in the surface layer is 50 μm. A method for producing an Al—Mg—Si based alloy sheet, characterized by being m or less.
2: P ≧ 2.9 × 10 ^-6 · t · w · D ^1/2 · v · exp {1600 / (T + 273)} · (R / 100) ^-0.5
However,
t: Outlet plate thickness (mm), w: Outlet plate width (mm), D: Roll diameter (mm),
v: Roll peripheral speed (mpm), T: Outlet plate surface temperature (° C), R: Cold rolling rate (%) Si 0.2-3.0%, Mg 0.2-3.0%, Ti 0.001-0.5% is contained as an essential element, and further Cu 0-2.5% (however, 0% means not included, the same applies hereinafter), Sn 0- Using direct casting and rolling equipment with twin rolls, Al alloy melt containing 0.2%, Zn 0-2.0% or more, Fe regulated to 1.0% or less, the balance consisting of Al and inevitable impurities Then, the rolling load P (ton) is directly cast and rolled on a plate having a thickness of 4 mm or less under the conditions satisfying the following two formulas, and then the plate is cold-rolled at a rolling rate of 70% or more, Solution treatment is performed in the range of 400 ° C to the melting temperature of the material, and after cooling, the solution is rapidly cooled to a range of 40 to 175 ° C at a cooling rate of 2 ° C / s or more, and wound in a coil shape at the above temperature. the maximum grain size of the metal structure of the plate 100 [mu] m or less, and Al-Mg-Si alloy which maximum length of consecutive Mg ₂ Si compounds of the surface layer portion, characterized in that the 50μm or less The method of production.
2: P ≧ 2.9 × 10 ^-6 · t · w · D ^1/2 · v · exp {1600 / (T + 273)} · (R / 100) ^-0.5
However,
t: Outlet plate thickness (mm), w: Outlet plate width (mm), D: Roll diameter (mm),
v: Roll peripheral speed (mpm), T: Outlet plate surface temperature (° C), R: Cold rolling rate (%) An alloy plate obtained by winding an Al-Mg-Si based alloy plate manufactured by the manufacturing method according to claim 1 or 3 into a coil shape, Al-Mg- manufactured by the manufacturing method according to claim 2 After any of the Si-based alloy plate and the Al-Mg-Si-based alloy plate manufactured by the manufacturing method according to claim 4 is subjected to a homogenization treatment for 2 to 24 hours at a temperature of 580 ° C or lower. A method for producing an Al-Mg-Si alloy sheet to be cold-rolled.   The Al-Mg-Si alloy plate according to any one of claims 1 to 5, wherein the molten Al alloy further includes at least one of Mn 0.01 to 0.5%, Cr 0.01 to 0.5%, and Zr 0.01 to 0.5%. Manufacturing method.

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