JP4410835B2 - Aluminum alloy thick plate and manufacturing method thereof - Google Patents

Description

The present invention relates to an aluminum alloy thick plate and a method for manufacturing the same.

  In general, aluminum alloy materials are used in various applications such as electric and electronic parts, manufacturing equipment, daily necessities, and machine parts in addition to semiconductor-related devices such as base substrates, transfer devices, and vacuum chambers. In addition, as a mold material used for a press mold, steel, cast steel or the like is used for mass production, but a zinc alloy cast material, an aluminum alloy cast material or the like is used for trial production. Furthermore, in recent years, expanded materials such as aluminum alloy rolled materials or forged materials have become widespread for medium and small volume production due to the tendency to reduce the number of products.

  Among these, as shown in FIG. 2, for example, the rolled material of the aluminum alloy is manufactured from the melting step S101 through the annealing step S600, and then inspected for distortion, plate thickness, surface flaws, etc. (See, for example, Kokai 2006-28181), covering the rolled front and back with a resin film made of vinyl chloride or polyethylene (for example, Kobe Steel Technical Report / Vol.52 No.2, Sep. 2002, registered trademark: Alhais, a registered trademark manufactured by Furukawa Sky Co., Ltd .: high plate is known) (S101 to S900).

  The product form in which the rolled front and back surfaces are covered with a resin film is because high-precision aluminum alloy thick plates are frequently used as parts for precision equipment, etc., so they are traded through a cut-sheet wholesaler with small dimensions and small numbers. This is because. That is, in the cut plate wholesaler, saw cutting is performed to make a small size of a dice for precision instrument parts use, and in the vacuum chamber use, end milling is partially performed, so that the non-processed part becomes the device exterior material. Therefore, for the purpose of preventing wrinkling during such cutting, the rolled front and back surfaces of high-precision aluminum alloy thick plates are distributed in the form of products covered with a resin film.

  This rolled material of aluminum alloy is usually manufactured by hot rolling an ingot to a predetermined thickness. However, such an aluminum alloy hot-rolled plate has a plate thickness and flatness controlled only by a rolling roll, so that it is difficult to obtain good plate thickness accuracy and flatness (particularly flatness in the rolling direction). . Also, since a thick oxide film is formed on the rolled surface during hot rolling, it is also difficult to control the flatness. Thus, a technique is disclosed in which cold rolling is performed at a rolling reduction of 5% or less that does not accumulate strain after hot rolling to improve sheet thickness accuracy (see, for example, Patent Document 1).

JP 2006-316332 A (paragraphs 0027 to 0028)

  However, the prior art disclosed in Patent Document 1 uses an aluminum alloy material as a thin plate having a thickness of about 1 mm.

  In addition, the surface defects described above are not only the beauty of the appearance of the product, but also a serious quality defect that impairs the function of the product, reducing the product yield, and at the same time requires a lot of man-hours to remove this defect. It is a factor that inhibits sex. For example, a customer who uses a small size of a dice, after processing the purchased product and delivering the product, discovers wrinkles at the stage where the coated resin film is peeled off at the product delivery destination. In the vacuum chamber application, if a fine flaw is a casting cavity, it becomes a functional defect, but if the flaw is fine, it is not possible to distinguish it from a damaged flaw, and it takes time to determine the flaw factor. In short, there is a problem in that sales opportunities to end customers are missed.

  In addition, the level of wrinkles in question has recently increased, and a wrinkle having a depth of 8 μm or more and a circle-equivalent diameter of about 0.1 mm is problematic because it can be found visually. Furthermore, it is difficult to eliminate all of the above-mentioned defects by the conventional manufacturing method. Also, mainly in vacuum chamber applications, it is rarely used as it is on the surface of the material, and alumite treatment and plating treatment are performed to improve corrosion resistance and weather resistance. In recent years, despite the fact that there is no defect in the base plate, a black streak-like shape having a length of about 3 μm in the rolling parallel direction is caused after the surface treatment as described above due to the remaining undissolved Ti-B. There is a problem that surface defects occur, and this improvement is urgently needed. In order to meet the customer demand for these surface defects, a high-precision aluminum alloy thick plate that can reliably eliminate this level of surface defects or surface defects caused by surface treatment before coating with a resin film is desired.

  The present invention has been made in view of the above problems, and has good plate thickness accuracy and flatness that can be produced in a semiconductor-related device such as a vacuum device chamber. An object of the present invention is to provide an aluminum alloy thick plate capable of suppressing surface defects caused by the above and a method for producing the same.

In order to solve the above problems, an aluminum alloy thick plate according to claim 1 is an aluminum alloy thick plate coated with a resin film, and the aluminum alloy thick plate is an aluminum alloy heat plate cut to a predetermined length. the surface between rolled plate, it is smoothed before being covered with the resin film, the flatness of the surface is below the rolling direction length 1m per 0.2 mm, ± thickness variation is desired thickness 0 It is characterized by being within 5%.

  As described above, by smoothing the surface (before coating the resin film), the variation in the surface flatness and the plate thickness is limited to a predetermined range, so that the semiconductor-related apparatus is not subjected to thinning processing such as cold rolling. For example, an aluminum alloy material for products requiring high accuracy in shape can be used. Furthermore, it is possible to suppress surface defects caused by wrinkles and black stripes.

  Furthermore, the aluminum alloy thick plate according to claim 2 is the aluminum alloy thick plate according to claim 1, containing Mg: 1.5 to 12.0 mass%, and further Si: 0.7 mass% or less. Fe: 0.8 mass% or less, Cu: 0.6 mass% or less, Mn: 1.0 mass% or less, Cr: 0.5 mass% or less, Zn: 0.4 mass% or less, Ti: 0. It is characterized in that it contains one or more of 1% by mass or less, and the balance is made of an aluminum alloy composed of Al and inevitable impurities.

  By containing such an element at a concentration in a predetermined range, it is possible to obtain an Al—Mg alloy thick plate having excellent characteristics such as strength in addition to plate thickness accuracy and flatness. Furthermore, in addition to suppressing surface defects due to wrinkles, black stripes, etc., it is also possible to suppress the occurrence of color unevenness on the surface.

  Moreover, the aluminum alloy thick plate according to claim 3 is the aluminum alloy thick plate according to claim 1, containing Mn: 0.3 to 1.6 mass%, and further Si: 0.7 mass% or less. Fe: 0.8 mass% or less, Cu: 0.5 mass% or less, Mg: 1.5 mass% or less, Cr: 0.3 mass% or less, Zn: 0.4 mass% or less, Ti: 0. It is characterized in that it contains one or more of 1% by mass or less, and the balance is made of an aluminum alloy composed of Al and inevitable impurities.

  By containing such an element in a concentration within a predetermined range, it is possible to obtain an Al—Mn alloy thick plate having excellent properties such as strength as well as plate thickness accuracy and flatness. Furthermore, in addition to suppressing surface defects due to wrinkles, black stripes, etc., it is also possible to suppress the occurrence of color unevenness on the surface.

  Further, the aluminum alloy thick plate according to claim 4 is the aluminum alloy thick plate according to claim 1, containing Mg: 0.3 to 1.5 mass%, Si: 0.2 to 1.6 mass%. Furthermore, Fe: 0.8 mass% or less, Cu: 1.0 mass% or less, Mn: 0.6 mass% or less, Cr: 0.5 mass% or less, Zn: 0.4 mass% or less, Ti : It contains one or more of 0.1% by mass or less, and the balance is made of an aluminum alloy composed of Al and inevitable impurities.

  By containing such an element at a concentration within a predetermined range, it is possible to obtain an Al—Mg—Si based alloy thick plate having excellent strength and other properties in addition to plate thickness accuracy and flatness. Furthermore, in addition to suppressing surface defects due to wrinkles, black stripes, etc., it is also possible to suppress the occurrence of color unevenness on the surface.

  Moreover, the aluminum alloy thick plate according to claim 5 is the aluminum alloy thick plate according to claim 1, wherein Zn: 3.0 to 9.0 mass%, Mg: 0.4 to 4.0 mass% is contained. Furthermore, Si: 0.7 mass% or less, Fe: 0.8 mass% or less, Cu: 3.0 mass% or less, Mn: 0.8 mass% or less, Cr: 0.5 mass% or less, Ti : 0.1 mass% or less, Zr: It contains 1 or more types among 0.25 mass% or less, The remainder consists of aluminum alloy which consists of Al and an unavoidable impurity, It is characterized by the above-mentioned.

  By containing such an element in a concentration within a predetermined range, it is possible to obtain an Al—Zn—Mg based alloy thick plate having excellent strength and other properties in addition to plate thickness accuracy and flatness. Furthermore, in addition to suppressing surface defects due to wrinkles, black stripes, etc., it is also possible to suppress the occurrence of color unevenness on the surface.

  Moreover, the manufacturing method of the aluminum alloy thick plate which concerns on Claim 6 is a manufacturing method of the aluminum alloy thick plate of Claim 1, Comprising: The melt | dissolution process which melt | dissolves an aluminum alloy and makes an aluminum alloy molten metal, The said aluminum A dehydrogenation step for removing hydrogen gas from the molten alloy, a filtration step for removing inclusions from the molten aluminum alloy from which the hydrogen gas has been removed, and an ingot by casting the molten aluminum alloy from which inclusions have been removed. A casting process to manufacture, a hot rolling process to manufacture a hot rolled sheet by hot rolling the ingot to a predetermined thickness, and a predetermined length and width in the rolling direction by cutting the hot rolled sheet And a smoothing treatment step of smoothing the surface of the cut hot-rolled plate, and in the smoothing treatment step, the removal thickness of the surface of the hot-rolled plate is about one side. 2 Characterized in that it is a 5 mm.

  Thus, by subjecting the surface of the hot-rolled plate to a smoothing process with a predetermined removal thickness, the plate thickness accuracy and flatness can be improved. Further, surface defects due to wrinkles, black stripes, etc. can be suppressed.

The method for producing an aluminum alloy thick plate according to claim 7 is the method for producing an aluminum alloy thick plate according to claim 6, wherein the ingot is kept at 400 ° C or higher before the hot rolling step. The soaking process is performed by a heat treatment at a temperature lower than the melting point for 1 hour or longer.
Thus, the structure of the ingot can be refined and homogenized by subjecting the ingot to heat treatment before hot rolling.

Moreover, the manufacturing method of the aluminum alloy thick plate which concerns on Claim 8 is a manufacturing method of the aluminum alloy thick plate of Claim 6 or Claim 7, Before the said smoothing process process, the said cut | disconnecting hot An annealing process for annealing the rolled sheet is performed.
Thus, the characteristics of a hot-rolled sheet can be improved by annealing the hot-rolled sheet.

Moreover, the manufacturing method of the aluminum alloy thick plate which concerns on Claim 9 is a manufacturing method of the aluminum alloy thick plate of any one of Claim 6 thru | or 8, The said smoothing process process is a cutting method, It is performed by any one or more of a grinding method and a polishing method.
By such a method, the thickness accuracy and flatness of the aluminum alloy thick plate are improved. Further, surface defects due to wrinkles, black stripes, etc. can be suppressed.

  The method for producing an aluminum alloy thick plate according to claim 10 is the method for producing an aluminum alloy thick plate according to any one of claims 6 to 9, wherein the aluminum alloy is claimed in claims 2 to 10. 5. The aluminum alloy according to any one of 5 above.

  By manufacturing with an aluminum alloy having such a composition, an aluminum alloy thick plate having characteristics according to the composition, good sheet thickness accuracy and flatness, and improved characteristics such as strength and surface properties is manufactured. be able to.

According to the aluminum alloy thick plate according to the present invention, even a thick plate with little plastic deformation has a desired plate thickness and a flat thick plate. Preferred. In addition, since surface defects due to wrinkles and black stripes are suppressed, the surface properties of the thick plate are good. Furthermore, by using a predetermined aluminum alloy, properties such as strength are improved, color unevenness on the surface is suppressed, and the surface properties of the thick plate are further improved.
According to the method for producing an aluminum alloy thick plate according to the present invention, an aluminum alloy thick plate having the above-described effects can be produced with high productivity.

It is a flowchart which shows the manufacturing method of the aluminum alloy thick board which concerns on this invention. It is a flowchart which shows an example of the manufacturing method of the aluminum alloy thick board which concerns on a prior art.

  Hereinafter, the best mode for realizing the aluminum alloy thick plate according to the present invention will be described.

[Configuration of aluminum alloy thick plate]
The aluminum alloy thick plate according to the present invention is an aluminum alloy hot-rolled plate (aluminum alloy hot-rolled plate) with a smoothed surface, and the flatness of the surface is 0.2 mm or less per 1 m in the rolling direction length. The variation is within ± 0.5% of the desired plate thickness. The aluminum alloy thick plate according to the present invention is a plate material having a plate thickness of 15 to 200 mm, but is not particularly limited, and can be appropriately changed according to the use of the aluminum alloy thick plate. Hereinafter, each element which comprises the aluminum alloy thick plate which concerns on this invention is demonstrated.

(Surface flatness: 0.2 mm or less per 1 m length in the rolling direction)
When a member with poor flatness is used as an internal member of a vacuum apparatus chamber such as a plasma processing apparatus, a member of a semiconductor-related device, when an adsorbed gas is released from the surface of the member when the pressure is reduced to a high vacuum, The degree of vacuum decreases. Therefore, it takes time to reach the target degree of vacuum, and the production efficiency decreases. Therefore, the flatness of the surface of the aluminum alloy thick plate according to the present invention is 0.2 mm / m or less. Moreover, since the flatness of the surface of a hot-rolled sheet is the most inferior in a rolling direction, it is set per 1 m in the rolling direction length. Such flatness is adjusted by a smoothing process and a correction process in the manufacturing method described later.

(Thickness variation: within ± 0.5% of desired thickness)
Since the aluminum alloy thick plate according to the present invention is manufactured in a product that requires high accuracy in shape, such as a member of a semiconductor-related device, high accuracy is also required in the plate thickness. In order to meet this requirement, the variation in thickness is within ± 0.5% of the desired thickness. Such plate thickness accuracy is adjusted by the smoothing process in the manufacturing method described later.

  In addition, in the aluminum alloy thick plate according to the present invention, the amount of hydrogen gas contained per 100 g is preferably 0.2 ml or less, and more preferably 0.1 ml or less. Hydrogen gas is generated from hydrogen in fuel, water adhering to metal, etc., and other organic substances. If a large amount of hydrogen gas is contained, it may cause pinholes or weaken the product. In addition, hydrogen accumulates and concentrates at the grain boundaries near the surface of the ingot, causing bulges in the ingot and creaking of the aluminum alloy thick plate due to the bulges, and the surface of the thick plate that appears as surface defects of the thick plate Potential defects arise. Further, if these internal defects of the vacuum chamber are present, the degree of vacuum is lowered due to release of gas atoms dissolved in the member to the surface when the pressure is reduced to a high vacuum. Therefore, it takes time to reach the target degree of vacuum, and the production efficiency decreases. In order to reduce the amount of hydrogen gas contained in the aluminum alloy thick plate, hydrogen gas is removed from the molten aluminum alloy before casting in a dehydrogenation step in the production method described later.

  The concentration of hydrogen gas in the ingot is, for example, from a sample cut out from the ingot (before soaking) and subjected to ultrasonic cleaning with alcohol and acetone, and then an inert gas stream melting thermal conductivity method (LIS AO6- 1993). The concentration of hydrogen gas in the aluminum alloy thick plate is, for example, a sample cut out from the aluminum alloy thick plate, immersed in NaOH, the oxide film on the surface removed with nitric acid, and ultrasonically cleaned with alcohol and acetone. From the above, it can be determined by the vacuum heating extraction volume method (LIS AO6-1993).

  The aluminum alloy thick plate according to the present invention may be made of any aluminum alloy, but Al—Mg alloy, Al—Mn alloy, Al—Mg—Si alloy, Al—Zn—Mg. A material suitable for the application can be selected from any one of the alloys. Hereafter, each element of an example of the aluminum alloy which comprises the aluminum alloy thick plate which concerns on this invention is demonstrated.

[Composition of Al-Mg alloy]
The Al—Mg-based alloy according to the present invention, that is, an aluminum alloy according to the 5000-based Al alloy contains Mg: 1.5 to 12.0 mass%, Si: 0.7 mass% or less, Fe: 0 0.8 mass% or less, Cu: 0.6 mass% or less, Mn: 1.0 mass% or less, Cr: 0.5 mass% or less, Zn: 0.4 mass% or less, Ti: 0.1 mass% or less 1 or more of them, and the balance consists of Al and inevitable impurities.

(Mg: 1.5-12.0 mass%)
Mg has the effect of improving the strength of the Al—Mg alloy. When the Mg content is less than 1.5% by mass, this effect is small. On the other hand, when the Mg content exceeds 12.0% by mass, the castability is remarkably deteriorated and the production of the product becomes impossible. Therefore, when using an Al—Mg alloy having the above component composition, the Mg content needs to be 12.0 mass%. Therefore, Mg content shall be 1.5-12.0 mass%.

(Si: 0.7 mass% or less)
Si is an element unavoidably contained in the aluminum alloy as a metal base impurity. Si has an effect of improving the strength of the aluminum alloy. On the other hand, Si is combined with Mn and Fe to produce an Al— (Fe) — (Mn) —Si intermetallic compound during casting. When Si content exceeds 0.7 mass%, a coarse intermetallic compound will arise in an ingot, and it will become easy to produce a color nonuniformity in the surface appearance after an alumite process. Therefore, the Si content is 0.7% by mass or less.

(Fe: 0.8% by mass or less)
Fe is an element unavoidably contained in the aluminum alloy as a metal base impurity. Fe has the effect of refining and stabilizing the crystal grains of the aluminum alloy and improving the strength. On the other hand, Al—Fe— (Mn) — (Si) -based intermetallic compounds are formed by being combined with Mn and Si during casting or the like. When the Fe content exceeds 0.8% by mass, a coarse intermetallic compound is generated in the ingot, and color unevenness tends to occur in the surface appearance after the alumite treatment. Therefore, the Fe content is 0.8% by mass or less.

(Cu: 0.6% by mass or less)
Cu has the effect of improving the strength by dissolving in an aluminum alloy. The strength for use as an Al—Mg alloy thick plate is sufficiently secured when the Cu content is 0.6% by mass, and the effect is saturated even if it is added beyond that. Therefore, Cu content shall be 0.6 mass% or less.

(Mn: 1.0% by mass or less)
Mn has the effect of improving the strength by dissolving in an aluminum alloy. On the other hand, if the Mn content exceeds 1.0% by mass, a coarse intermetallic compound is generated in the ingot, and color unevenness is likely to occur in the surface appearance after the alumite treatment. Therefore, the Mn content is 1.0% by mass or less.

(Cr: 0.5% by mass or less)
Cr precipitates as a fine compound during casting or heat treatment, and has the effect of suppressing crystal grain growth. On the other hand, when the Cr content exceeds 0.5% by mass, coarse Al—Cr intermetallic compounds are formed as primary crystals, and color unevenness is likely to occur in the surface appearance after the alumite treatment. Therefore, Cr content shall be 0.5 mass% or less.

(Zn: 0.4 mass% or less)
Zn has the effect of improving the strength of the aluminum alloy. The strength for use as an Al—Mg alloy thick plate is sufficiently secured when the Zn content is 0.4 mass%, and the effect is saturated even if it is added beyond that. Therefore, Zn content shall be 0.4 mass% or less.

(Ti: 0.1% by mass or less)
Ti has the effect of refining the crystal grains of the aluminum alloy. Even if the Ti content exceeds 0.1% by mass, the effect is saturated. Therefore, the Ti content is 0.1% by mass or less.

[Composition of Al-Mn alloy]
Next, each element of the Al—Mn alloy will be described. The Al—Mn alloy according to the present invention, that is, an aluminum alloy according to the 3000 series Al alloy contains Mn: 0.3 to 1.6 mass%, Si: 0.7 mass% or less, Fe: 0 0.8 mass% or less, Cu: 0.5 mass% or less, Mg: 1.5 mass% or less, Cr: 0.3 mass% or less, Zn: 0.4 mass% or less, Ti: 0.1 mass% or less 1 or more of them, and the balance consists of Al and inevitable impurities.

(Mn: 0.3 to 1.6% by mass)
Mn has the effect of improving the strength by dissolving in an aluminum alloy. When the Mn content is less than 0.3% by mass, this effect is small. On the other hand, when the Mn content exceeds 1.6% by mass, coarse Al— (Fe) —Mn— (Si) -based intermetallic compounds are formed. It occurs in the ingot and color unevenness tends to occur in the surface appearance after the anodized treatment. Therefore, the Mn content is set to 0.3 to 1.6% by mass.

(Mg: 1.5% by mass or less)
Mg has the effect of improving the strength of the aluminum alloy. The strength for use as an Al-Mn alloy thick plate is sufficiently secured when the Mg content is 1.5% by mass, and the effect is saturated even if it is added beyond that. Therefore, Mg content shall be 1.5 mass% or less.

(Si: 0.7% by mass or less, Fe: 0.8% by mass or less, Cu: 0.5% by mass or less, Cr: 0.3% by mass or less, Zn: 0.4% by mass or less, Ti: 0. 1% by mass or less)
Since the effects of Si, Fe, Cu, Cr, Zn, and Ti are the same as those in the Al—Mg alloy, they are omitted.

[Composition of Al-Mg-Si alloy]
Next, each element of the Al—Mg—Si alloy will be described. The Al—Mg—Si alloy according to the present invention, that is, an aluminum alloy according to the 6000 Al alloy contains Mg: 0.3 to 1.5 mass%, Si: 0.2 to 1.6 mass%, Furthermore, Fe: 0.8 mass% or less, Cu: 1.0 mass% or less, Mn: 0.6 mass% or less, Cr: 0.5 mass% or less, Zn: 0.4 mass% or less, Ti: 0 1 or more of 1% by mass or less, with the balance being Al and inevitable impurities.

(Mg: 0.3-1.5% by mass)
Mg has an effect of improving the strength of the aluminum alloy, and further coexists with Si to form Mg ₂ Si and improve the strength of the aluminum alloy. If the Mg content is less than 0.3% by mass, these effects are small. On the other hand, when the Mg content exceeds 1.5% by mass, the characteristics of an Al—Mg-based (5000-based Al) alloy may be obtained. Therefore, Mg content shall be 0.3-1.5 mass%.

(Si: 0.2-1.6% by mass)
Si has the effect of improving the strength of the aluminum alloy, and further coexists with Mg to form Mg ₂ Si and improve the strength of the aluminum alloy. When the Si content is less than 0.2% by mass, these effects are small. On the other hand, when the Si content exceeds 1.6% by mass, a coarse intermetallic compound is generated in the Al—Mg—Si alloy, and color unevenness is likely to occur in the surface appearance after the alumite treatment. Therefore, Si content shall be 0.2-1.6 mass%.

(Cu: 1.0% by mass or less)
Cu has an effect of improving the strength by solid solution in the aluminum alloy. On the other hand, if the Cu content exceeds 1.0% by mass, the corrosion resistance of the Al—Mg—Si alloy is lowered. Therefore, the Cu content is 1.0% by mass or less.

(Zn: 0.4 mass% or less)
Zn has the effect of improving the strength of the aluminum alloy. On the other hand, when the Zn content exceeds 0.4 mass%, the corrosion resistance of the Al—Mg—Si alloy decreases. Therefore, Zn content shall be 0.4 mass% or less.

(Fe: 0.8 mass% or less, Mn: 0.6 mass% or less, Cr: 0.5 mass% or less, Ti: 0.1 mass% or less)
Since the effects of Fe, Mn, Cr, and Ti are the same as those in the Al—Mg alloy, the description thereof is omitted.

[Composition of Al-Zn-Mg alloy]
Next, each element of the Al—Zn—Mg alloy will be described. The Al—Zn—Mg alloy according to the present invention, that is, the aluminum alloy according to the 7000 Al alloy contains Zn: 3.0 to 9.0 mass%, Mg: 0.4 to 4.0 mass%, Furthermore, Si: 0.7 mass% or less, Fe: 0.8 mass% or less, Cu: 3.0 mass% or less, Mn: 0.8 mass% or less, Cr: 0.5 mass% or less, Ti: 0 1 mass% or less, Zr: One or more of 0.25 mass% or less are contained, and the balance consists of Al and inevitable impurities.

(Zn: 3.0 to 9.0% by mass)
Zn has the effect of improving the strength of the aluminum alloy. When the Zn content is less than 3.0% by mass, this effect is small. On the other hand, when the Zn content exceeds 9.0% by mass, a coarse intermetallic compound is produced, and the surface appearance after the alumite treatment is colored. Unevenness is likely to occur, and resistance to SCC (stress corrosion cracking) is reduced. Therefore, Zn content shall be 3.0-9.0 mass%.

(Mg: 0.4-4.0% by mass)
Mg has the effect of improving the strength of the aluminum alloy. When the Mg content is less than 0.4% by mass, this effect is small. On the other hand, when the Mg content exceeds 4.0% by mass, a coarse intermetallic compound is produced, and the surface appearance after the alumite treatment is uneven in color. It tends to occur, and the resistance to SCC (stress corrosion cracking) decreases. Therefore, the Mg content is set to 0.4 to 4.0% by mass.

(Cu: 3.0% by mass or less)
Cu has the effect of improving the strength by solid solution in the aluminum alloy. On the other hand, when the Cu content exceeds 3.0% by mass, the corrosion resistance of the Al—Zn—Mg alloy is lowered. Therefore, the Cu content is 3.0% by mass or less.

(Zr: 0.25 mass% or less)
Zr has the effect of refining and stabilizing the crystal grains of the aluminum alloy. On the other hand, if the Zr content exceeds 0.25% by mass, a coarse intermetallic compound is produced, and color unevenness is likely to occur on the surface appearance after the alumite treatment. Therefore, the Zr content is 0.25% by mass or less.

(Si: 0.7 mass% or less, Fe: 0.8 mass% or less, Mn: 0.8 mass% or less, Cr: 0.5 mass% or less, Ti: 0.1 mass% or less)
Since the effects of Si, Fe, Mn, Cr, and Ti are the same as those in the Al—Mg alloy, description thereof is omitted.

  In any of the Al—Mg alloy, Al—Mn alloy, Al—Mg—Si alloy, and Al—Zn—Mg alloy, the contents of V, B, etc. as unavoidable impurities are 0 respectively. If it is 0.01 mass% or less, it does not affect the characteristics of the aluminum alloy thick plate of the present invention. However, in order to prevent ingot cracking at the time of slab ingot, Ti may be added as a refiner consisting of a master alloy with B. As will be described later, if coarse Ti-B particles remain undissolved, anodized Black streaks may occur after surface treatment such as treatment or plating. For this reason, it is preferable not to add B, such as using an Al-Ti micronizing agent, but even if black streaks occur due to the addition of B, by performing an appropriate smoothing treatment as described later, It is possible to remove black stripes.

[Method of manufacturing aluminum alloy thick plate]
Next, a method for producing an aluminum alloy thick plate according to the present invention will be described with reference to the drawings. FIG. 1 is a flowchart showing a method of manufacturing an aluminum alloy thick plate according to the present invention. In the method for producing an aluminum alloy thick plate according to the present invention, first, an aluminum alloy having any one of the above compositions is melted to form a molten aluminum alloy (melting step S11), and hydrogen gas and inclusions are respectively removed from the molten aluminum alloy. (Dehydrogenation step S12, filtration step S13). The molten aluminum alloy is cast to produce an ingot (casting step S14), and the ingot is hot-rolled to a predetermined thickness to produce a hot-rolled sheet (hot-rolling step S30). And a hot-rolled board is cut | disconnected (cutting process S50), and the surface is smoothed and finished (smoothing process process S70). Further, before the hot rolling, the ingot may be homogenized by heat treatment (soaking step S20). Moreover, you may correct | amend distortion of a hot-rolled board (correction process S40). Further, the hot rolled sheet may be annealed (annealing step S60). In addition, the aluminum alloy thick plate manufactured in this way becomes a product form in which the front and back surfaces are covered with a resin film through an inspection step S80 and a resin film coating step S90. Moreover, in FIG. 1, although it complete | finishes through resin film coating process S90 for convenience, the aluminum alloy thick board which concerns on this invention is a thing of the stage which finished smoothing process S70. Details of each step will be described below.

(Dissolution process)
The melting step S11 is a step of melting an aluminum alloy having a predetermined composition to form a molten aluminum alloy, and is performed by a known facility and method.

(Dehydrogenation process)
The dehydrogenation step S12 is a step of removing hydrogen gas from the molten aluminum alloy, and the hydrogen gas can be suitably removed by performing fluxing, chlorine refining, in-line refining, or the like on the molten aluminum alloy. Further, when the dehydrogenation apparatus is a rotary dehydrogenation apparatus such as sniff or a porous plug (see Japanese Patent Application Laid-Open No. 2002-146447), the removal can be performed more suitably.

(Filtration process)
Filtration process S13 is a process of removing mainly an oxide and a nonmetallic inclusion from aluminum alloy molten metal with a filtration apparatus. The filter device is provided with a ceramic tube using alumina having a particle size of about 1 mm, for example, and the oxides and inclusions can be removed by passing molten aluminum alloy through the ceramic tube.

  By the dehydrogenation step S12 and the filtration step S13, it is possible to obtain a high-quality aluminum alloy ingot in which internal defects are suppressed in the subsequent casting step S14. Further, since deposition of oxide deposits (dross) can be suppressed, dross removal work can be reduced.

(Casting process)
The casting step S14 is a step for producing an aluminum alloy ingot by forming and solidifying a molten aluminum alloy into a predetermined shape such as a rectangular parallelepiped shape with a casting apparatus configured to include a water-cooled mold, for example. As a casting method, a semi-continuous casting method can be used. In the semi-continuous casting method, molten metal is poured from above into a metal water-cooled mold with an open bottom, and the solidified metal is continuously removed from the bottom of the water-cooled mold to obtain an ingot of a predetermined thickness. It is. This semi-continuous casting method may be performed either vertically or horizontally.

(Soaking process-treatment temperature: 400 ° C or higher and lower than the melting point of the aluminum alloy, treatment time: 1 hour or more)
In the soaking process S20, heat treatment is performed on the aluminum alloy ingot, thereby removing internal stress, homogenizing the solute elements segregated during casting, and diffusing and dissolving the intermetallic compound crystallized during casting to form a structure. This is a process for homogenization. The heat treatment is performed according to a conventional method by holding at 400 ° C. or higher and lower than the melting point of the aluminum alloy for 1 hour or longer. If the soaking temperature is less than 400 ° C., the above effect is insufficient. Moreover, if processing time is less than 1 hour, the solid solution of an intermetallic compound is inadequate and it precipitates easily. On the other hand, when the soaking temperature reaches the melting point of the aluminum alloy according to the present invention, a phenomenon called burning in which a part of the surface of the aluminum alloy ingot is melted is likely to cause surface defects of the aluminum alloy thick plate. Therefore, the soaking temperature is 400 ° C. or higher and lower than the melting point of the aluminum alloy, and the annealing is performed for 1 hour or longer.

(Hot rolling process)
The hot rolling step S30 is a step of hot rolling an aluminum alloy ingot to obtain a plate material (aluminum alloy hot rolled plate) having a predetermined thickness. As the hot rolling method, a reverse (reversible) hot rolling mill can be used. The aluminum alloy ingot is heated to a predetermined temperature and rolled down by a reverse hot rolling mill to produce an aluminum alloy hot rolled sheet having a predetermined thickness. The plate thickness in this step (the plate thickness of the aluminum alloy hot-rolled plate) is a plate thickness obtained by adding a decrease in the smoothing treatment step S70 described later to the desired plate thickness of the aluminum alloy thick plate. About 200 mm is preferable.

(Correction process)
The correction step S40 is a step of correcting and flattening the distortion generated by hot rolling of the aluminum alloy hot-rolled sheet, and is performed by a known facility or method such as a stretcher or a tension leveler.

(Cutting process)
The cutting step S50 is a step of cutting the aluminum alloy hot-rolled sheet into a desired length (and width).

(Annealing process)
The annealing step S60 is a step of removing the internal stress or homogenizing the internal structure by applying a heat treatment to the aluminum alloy thick plate. Moreover, you may give the tempering by a solution treatment and an aging treatment. These processes may be performed after the smoothing process step S70. For example, as disclosed in Japanese Patent Laid-Open No. 63-115617, surface flatness can be improved by performing heat treatment.

(Smoothing process)
The smoothing treatment step S70 is a step of smoothing the surface (rolled surface) of the aluminum alloy hot-rolled plate and adjusting the plate thickness.
Here, the removal thickness of the surface of the hot-rolled sheet is 2 to 5 mm per side. By setting the removal thickness to 2 mm or more, the flatness and the variation in the plate thickness can be adjusted as desired, and surface defects caused by wrinkles can be suppressed.

  In addition, as described above, a black streak-like surface defect having a length of about 3 μm in the rolling parallel direction after surface treatment such as alumite treatment or plating treatment has been carried out in recent years, even though the base plate has no defect. As a result of diligent investigation of the cause, Ti-B, an ingot refining agent (crystal grain refining agent) at the time of casting, is rapidly solidified in the vicinity of the slab ingot mold. The inventors have found out that this is due to the fact that it was not dissolved in the part. Therefore, by setting the removal thickness to 2 mm or more, it is possible to remove the undissolved portion of the ingot refining agent Ti-B, so black streaks can be obtained even if alumite treatment or plating treatment is performed. No surface defects occur. The removal thickness is 5 mm or less from the viewpoint of yield and cost performance.

  As the smoothing treatment method, a cutting method such as end mill cutting or diamond bite cutting, a grinding method in which the surface is ground with a grindstone, a polishing method such as buff polishing, or the like can be used, but the method is not limited thereto.

  Further, in the smoothing treatment step S70, after suppressing surface defects due to flatness, variation in plate thickness, wrinkles, black stripes, etc., hairline processing may be further performed. By applying a hairline process, the surface of the thick plate can be rolled. As a method of hairline processing, a polishing method such as a belt type or a wheel type is known, but any method may be adopted, and a polishing nonwoven fabric used for a hairline processing such as a belt type or a wheel type As for the abrasive grain type, it is known that it consists of a single substance such as alumina, silicon carbide, zirconia, or a mixture thereof, and an adhesive such as resin or glue. Coarse # 120 to # 220. In addition, when using an abrasive non-woven fabric having a rotating outer diameter of a belt or wheel of φ400 mm, it contains a grease for preventing seizure and is preferably subjected to hairline processing at a rotational speed of 1500 rpm or less, but is limited to these conditions. It is not something.

  Regarding the surface defects caused by wrinkles, the size of wrinkles that can be visually recognized by the human eye is 8 μm or more deep, and the size of wrinkles that are difficult to determine during inspection is up to 20 μm. The depth of 20 μm is an indentation caused by foreign matter or roll wrinkles, and such a defect is not originally a functional defect. For this reason, such indented wrinkles can be discriminated from functional defects because the smooth portions, wrinkles and boundaries on the surface of the thick plate can be made smooth by applying hairline processing (2 to 3 μm in machining allowance). There is an effect that can be easily. In addition, if economic efficiency is ignored, the effect of the present invention can be obtained if only 2 mm or more of hairline processing is performed per side.

  The aluminum alloy thick plate thus manufactured is then inspected for distortion, plate thickness, surface flaws, etc. in the inspection step S80, and then the front and back surfaces are made of resin film in the resin film coating step S90. Covered.

  Although the best mode for carrying out the present invention has been described above, examples in which the effects of the present invention have been confirmed will be specifically described in comparison with comparative examples that do not satisfy the requirements of the present invention. . In addition, this invention is not limited to this Example.

[Example 1: Preparation of test material]
(Al-Mg alloy)
Alloy No. shown in Table 1 An aluminum alloy having a composition of 5a to 5v (5k: JIS5052 alloy, 5l: JIS5083 alloy, 5v: no addition of Ti and B) is melted, dehydrogenated and filtered, and then cast into a casting having a thickness of 500 mm. A lump was made. This ingot was heated at 500 ° C. for 4 hours and soaked, and then hot-rolled to produce an aluminum alloy hot-rolled sheet having a thickness of about 25 mm and a thickness of about 20 mm. After this aluminum alloy hot-rolled sheet was cut into a rolling direction length of 2000 mm × width of 1000 mm, the rolled surface (both sides) was smoothed to obtain an aluminum alloy thick plate (cut plate) having a thickness of 20 mm. In addition, about the thing containing Ti, Ti-B master alloy is added in order to prevent ingot cracking. The effect of the smoothing treatment was compared by three types of methods: end milling, end milling + hairline processing (using a belt-type abrasive nonwoven fabric), and hairline processing. In addition, what performed an end mill process used the aluminum alloy hot-rolled sheet of about 25 mm thickness, and what performed only a hairline process used the aluminum alloy hot-rolled sheet of about 20 mm in thickness.

The end mill processing was performed by modifying an end mill processing machine (milling machine) manufactured by WASSER GmbH (German machine manufacturer, GmbH is a company). The rough chip was made of carbide, the finishing chip was made of diamond, and the machining allowance was the amount of pressing of the disk from the zero point, and the total tip was adjusted to about 2.5 mm / side.
Specifically, 30 rough chips and 2 finishing chips were mounted in the vicinity of the circumference of the lower surface of the disk, the disk was lowered onto the work piece, rotated, and then cut by sending it in the longitudinal direction of the plate. Since the finish chip pop-out amount is mounted so as to protrude slightly from the rough chip, the finished chip is shaped so that the surface of the rough chip cut off is followed up.

For the hairline processing, an aluminum plate buffing machine manufactured by Nomizu Machinery Co., Ltd. was used by modifying it so that a polishing nonwoven wheel could be attached to the buffing roll part. The wheel is Polytex (registered trademark) KF wheel MA manufactured by Koyo Co., Ltd. (coarse (# 150), outer diameter φ400 mm, grease impregnated, using brown fused alumina as the abrasive grain type and resin bond as the adhesive) )It was used.
Then, polishing was performed under the condition that the machining allowance was about 3.0 μm / single side (with oscillation (two reciprocations)). In addition, the grinding | polishing cost WHEREIN: The level | step difference of a trial grinding | polishing part is Veco instruments Inc. The shape was measured with “WYKO NT3300 (surface shape measurement system)” manufactured by USA (USA), and the depth of the unevenness was measured and confirmed.

(Al-Mn alloy)
Alloy No. shown in Table 1 An aluminum alloy having a composition of 3a to 3e (3e is not added with Ti and B) was dissolved, subjected to dehydrogenation treatment and filtration, and then cast to produce an ingot having a thickness of 500 mm. This ingot was hot-rolled to produce an aluminum alloy hot-rolled sheet having a thickness of about 25 mm and a thickness of about 20 mm. After this aluminum alloy hot-rolled sheet was cut into a rolling direction length of 2000 mm × width of 1000 mm, a smoothing process was performed on the rolled surface (both sides) to obtain a 20 mm thick aluminum alloy thick plate (cut plate). In addition, about the thing containing Ti, Ti-B master alloy is added in order to prevent ingot cracking. The effect of the smoothing treatment was compared by three types of methods: end milling, end milling + hairline processing (using a belt-type abrasive nonwoven fabric), and hairline processing. In addition, what performed an end mill process used the aluminum alloy hot-rolled sheet of about 25 mm thickness, and what performed only a hairline process used the aluminum alloy hot-rolled sheet of about 20 mm in thickness. The end milling and hairline processing methods are the same as in the case of the Al—Mg alloy.

[Example 1: Evaluation]
The following evaluation was performed on the obtained aluminum alloy thick plate, and the results are shown in Tables 2 and 3. Moreover, the aluminum alloy hot-rolled board (thickness 20mm) which does not implement a smoothing process was also manufactured, and it evaluated as a comparative example. Alloy No. Since 5n could not be produced on an aluminum alloy hot-rolled sheet as will be described later, the subsequent treatment and evaluation were not performed.

(Flatness)
For the evaluation of flatness, the amount of warpage (flatness) per 1 m in the rolling direction of the test material was measured. The acceptance criterion for flatness was a flatness of 0.2 mm / m or less.

(Thickness accuracy)
The plate thicknesses at a total of 6 points from the four corners of the test material and from the half of the length of the side in the rolling direction to the inner 20 mm part in the width direction were measured using a micrometer. When the thickness of all six points is in the range of 20.0 ± 0.06 mm (19.94 to 20.06 mm), “◎”, 20.0 ± 0.10 mm ( 20.0 mm ± 0.5%, 19.90-20.10 mm) were evaluated as “good” as good.

(Strength)
A tensile test piece according to JIS No. 5 was cut out from the test material. A tensile test according to JISZ2241 was carried out on this test piece, and the tensile strength and proof stress (0.2% proof stress) were measured. The acceptance criteria for strength is alloy no. 5a-5v (Al-Mg alloy) has a tensile strength of 180 N / mm ² or more, alloy no. 3a to 3e (Al—Mn alloy) had a tensile strength of 90 N / mm ² or more.

(Surface properties)
In order to evaluate the effect of the smoothing treatment on the surface properties, the specimen material (40 sheets each) was subjected to an alumite treatment, and the appearance of the surface was observed.
An alumite film having a thickness of 10 μm was formed on the surface of the test material by sulfuric acid alumite treatment (15% sulfuric acid, 20 ° C., current density 2 A / dm ² ). Then, the surface properties due to surface wrinkles and the surface properties due to black stripes were examined.

<Evaluation of surface properties by wrinkles after anodizing>
The appearance of this anodized surface was observed, and the surface property evaluation with wrinkles was evaluated as “◎” for those with no cutting plate out of 40 sheets in which wrinkles were discriminated with the naked eye. If the cutting surface is discriminated from 1 to 4 out of 40, the surface property evaluation by scissors is “Good”, and the cutting disc from which scissors are discriminated by the naked eye is 5 or more out of 40 The surface property evaluation by wrinkles was evaluated as “x” because it was poor.

<Evaluation of surface properties by black stripes after anodizing>
Observe black streaks (not functional defects) on the alumite-treated surface. If black streaks were not found with the naked eye, the surface property evaluation with black streaks was evaluated as “Good”. Those in which streaks were found were evaluated as “x” because the surface property evaluation with black streaks was poor.

  Furthermore, the surface properties due to surface color unevenness were also examined. Note that this surface texture is only a desirable surface texture for the present invention. Therefore, even if this surface texture is not satisfied, the surface texture that satisfies the surface texture due to wrinkles and black stripes is the present invention. The minimum objectives are achieved.

<Surface property evaluation by color unevenness after anodizing>
Observe the appearance of the alumite-treated surface. If the appearance is not uneven, the surface property evaluation by color unevenness is good. If it is uneven, the surface texture evaluation by color unevenness is poor. It was evaluated with “×” as being.

  In addition, since the value of intensity | strength only by end mill process + hairline process and hairline process is the same as the intensity value only by end mill process, description is abbreviate | omitted in a table | surface.

  Alloy No. The aluminum alloy thick plate composed of 5a to 5l and 5v has a content of additive elements within an appropriate range, and has been subjected to an appropriate smoothing treatment on the surface, so that strength, flatness, plate thickness accuracy, And the surface properties were good. Moreover, sufficient strength and good surface properties were obtained even when compared with an aluminum alloy hot-rolled sheet that had not been smoothed. In contrast, alloy no. The aluminum alloy thick plate made of 5 m was insufficient in strength because the Mg content was insufficient. On the other hand, Alloy No. Since the aluminum alloy thick plate made of 5n has an excessive Mg content, casting cracks occurred, and the specimens could not be produced. Alloy No. The aluminum alloy thick plate made of 5o, 5p, 5r, and 5s has excessive Si, Fe, Mn, and Cr contents, so that a coarse intermetallic compound is formed, and the surface appearance after the alumite treatment is uneven in color. Produced. Alloy No. The aluminum alloy thick plates made of 5q, 5t, and 5u have Cu, Zn, and Ti contents exceeding the appropriate ranges, respectively. As compared with 5f, 5j, and 5c, no improvement in strength and surface properties was observed.

  In addition, regarding the difference in surface smoothing method, the surface properties due to wrinkles are improved in the case of end milling + hairline processing with proper removal amount or end milling only compared to hairline processing with a small amount of removal. Confirmed to do. In addition, the wrinkles found in the conventional hot-rolled sheet cutting plate are identified as including fine wrinkles of a size that can barely be found with the naked eye, but with only hairline processing. The wrinkles found on the board were clearly visible. Therefore, the effect that the functional defect can be easily distinguished only by the hairline processing was confirmed.

  Furthermore, when only hairline processing is used, the amount of removal is small, so black streaks cannot be prevented. However, when only end milling or end milling + hairline processing is used, the amount of removal is appropriate, preventing black streaks. It was confirmed that it was possible. In addition, since the 5v aluminum alloy thick plate does not use the ingot refining agent Ti-B at the time of slab ingot, any surface is not affected by the difference in the surface smoothing method. It was confirmed that black stripes can be prevented from occurring even by the smoothing method.

  Alloy No. The aluminum alloy thick plate made of 3a, 3b, 3e has an additive element content within an appropriate range, and has been subjected to an appropriate smoothing treatment on the surface, so that strength, flatness, plate thickness accuracy, and The surface properties were good. Moreover, sufficient strength and good surface properties were obtained even when compared with an aluminum alloy hot-rolled sheet that had not been smoothed. In contrast, alloy no. The aluminum alloy thick plate made of 3c was insufficient in Mn content, so that sufficient strength was not obtained. On the other hand, Alloy No. Since the aluminum alloy thick plate made of 3d has an excessive Mn content, a coarse intermetallic compound was formed, and the appearance of the surface after the alumite treatment was uneven in color.

  In addition, regarding the difference in surface smoothing method, the surface properties due to wrinkles are improved in the case of end milling + hairline processing with proper removal amount or end milling only compared to hairline processing with a small amount of removal. Confirmed to do. In addition, the wrinkles found in the conventional hot-rolled sheet cutting plate are identified as including fine wrinkles of a size that can barely be found with the naked eye, but with only hairline processing. The wrinkles found on the board were clearly visible. Therefore, the effect that the functional defect can be easily distinguished only by the hairline processing was confirmed.

  Furthermore, when only hairline processing is used, the amount of removal is small, so black streaks cannot be prevented. However, when only end milling or end milling + hairline processing is used, the amount of removal is appropriate, preventing black streaks. It was confirmed that it was possible. In addition, since the aluminum alloy thick plate made of 3e does not use the ingot refining agent Ti-B at the time of slab ingot, any surface is not affected by the difference in the surface smoothing method. It was confirmed that black stripes can be prevented from occurring even by the smoothing method.

  The aluminum alloy hot-rolled sheet not subjected to the smoothing treatment had accumulated processing strain, warped in the rolling direction, and had poor flatness. In addition, the plate thickness accuracy was often inferior to that of aluminum alloy thick plates having the same composition. Furthermore, the surface properties due to wrinkles and black stripes were poor. Also, the flatness value only for hairline processing and the evaluation of the thickness accuracy of the cut plate are almost the same as the evaluation of the flatness value of the aluminum hot rolled plate (without smoothing treatment) and the thickness accuracy of the cut plate. (When the machining allowance is 2 to 3 μm, the accumulated machining distortion is not reduced, so the warpage is large in the rolling direction and the flatness is poor).

[Example 2: Preparation of test material]
(Al-Mg-Si alloy)
Alloy No. shown in Table 4 An aluminum alloy having a composition of 6a to 6g was dissolved, subjected to dehydrogenation treatment and filtration, and then cast to produce an ingot having a thickness of 500 mm. This ingot was hot-rolled to produce an aluminum alloy hot-rolled sheet having a thickness of about 25 mm and a thickness of about 20 mm. After this aluminum alloy hot-rolled sheet was cut into a rolling direction length of 2000 mm × width of 1000 mm, a smoothing process was performed on the rolled surface (both sides) to obtain a 20 mm thick aluminum alloy thick plate (cut plate). In addition, about the thing containing Ti, Ti-B master alloy is added in order to prevent ingot cracking. The effect of the smoothing treatment was compared by three types of methods: end milling, end milling + hairline processing (using a belt-type abrasive nonwoven fabric), and hairline processing. In addition, what performed an end mill process used the aluminum alloy hot-rolled sheet of about 25 mm thickness, and what performed only a hairline process used the aluminum alloy hot-rolled sheet of about 20 mm in thickness. The end milling and hairline processing methods are the same as in the case of the Al—Mg alloy. Further, the obtained aluminum alloy thick plate was subjected to a solution treatment at 520 ° C. and an aging treatment at 175 ° C. for 8 hours.

(Al-Zn-Mg alloy)
Alloy No. shown in Table 4 An aluminum alloy having a composition of 7a to 7g was dissolved, subjected to dehydrogenation treatment and filtration, and then cast to produce an ingot having a thickness of 500 mm. This ingot was hot-rolled to produce an aluminum alloy hot-rolled sheet having a thickness of about 25 mm and a thickness of about 20 mm. After this aluminum alloy hot-rolled sheet was cut into a rolling direction length of 2000 mm × width of 1000 mm, a smoothing process was performed on the rolled surface (both sides) to obtain a 20 mm thick aluminum alloy thick plate (cut plate). In addition, about the thing containing Ti, Ti-B master alloy is added in order to prevent ingot cracking. The effect of the smoothing treatment was compared by three types of methods: end milling, end milling + hairline processing (using a belt-type abrasive nonwoven fabric), and hairline processing. In addition, what performed an end mill process used the aluminum alloy hot-rolled sheet of about 25 mm thickness, and what performed only a hairline process used the aluminum alloy hot-rolled sheet of about 20 mm in thickness. The end milling and hairline processing methods are the same as in the case of the Al—Mg alloy. Furthermore, the obtained aluminum alloy thick plate was subjected to a solution treatment at 470 ° C., and an aging treatment was performed at 120 ° C. for 48 hours.

[Example 2: Evaluation]
The obtained aluminum alloy thick plate was evaluated for strength and surface properties in the same manner as in Example 1, and the results are shown in Tables 5 and 6. Moreover, the aluminum alloy hot-rolled sheet (thickness 20 mm) which does not implement a smoothing process was also manufactured, the solution treatment and the aging treatment were performed on the same conditions, and it evaluated as a comparative example. The acceptance criteria for strength is alloy no. 6a to 6g (Al—Mg—Si based alloys) have a tensile strength of 200 N / mm ² or more, alloy no. 7a to 7g (Al—Zn—Mg based alloy) had a tensile strength of 250 N / mm ² or more.
In addition, since the value of intensity | strength only by end mill process + hairline process and hairline process is the same as the intensity value only by end mill process, description is abbreviate | omitted in a table | surface.

  Alloy No. The aluminum alloy thick plates made of 6a, 6b, and 6g had good strength and surface properties because the content of additive elements was within an appropriate range and the surface was appropriately smoothed. Moreover, sufficient strength and good surface properties were obtained even when compared with an aluminum alloy hot-rolled sheet that had not been smoothed. In contrast, Alloy No. The aluminum alloy thick plates made of 6c and 6e were insufficient in Si and Mg contents, so that sufficient strength was not obtained. On the other hand, Alloy No. Since the 6d aluminum alloy thick plate has an excessive Si content, a coarse intermetallic compound was formed, and the surface appearance after the alumite treatment was uneven in color. In addition, Alloy No. The aluminum alloy thick plate made of 6f has the characteristics of Al-Mg-based (5000-based Al) alloy due to the excessive Mg content, so the strength improvement effect by solution treatment and aging treatment cannot be obtained. Alloy No. with Mg content in proper range Compared with 6a and 6b, the strength decreased.

  In addition, regarding the difference in surface smoothing method, the surface properties due to wrinkles are improved in the case of end milling + hairline processing with proper removal amount or end milling only compared to hairline processing with a small amount of removal. Confirmed to do. In addition, the wrinkles found in the conventional hot-rolled sheet cutting plate are identified as including fine wrinkles of a size that can barely be found with the naked eye, but with only hairline processing. The wrinkles found on the board were clearly visible. Therefore, the effect that the functional defect can be easily distinguished only by the hairline processing was confirmed.

  Furthermore, when only hairline processing is used, the amount of removal is small, so black streaks cannot be prevented. However, when only end milling or end milling + hairline processing is used, the amount of removal is appropriate, preventing black streaks. It was confirmed that it was possible. In addition, since the aluminum alloy thick plate made of 6 g does not use the ingot refining agent Ti-B at the time of slab ingot, any surface is not affected by the difference in the method of the surface smoothing treatment. It was confirmed that black stripes can be prevented from occurring even by the smoothing method.

  Alloy No. The aluminum alloy thick plates made of 7a, 7b, and 7g had good strength and surface properties because the content of additive elements was within an appropriate range and the surface was appropriately smoothed. Moreover, sufficient strength and good surface properties were obtained even when compared with an aluminum alloy hot-rolled sheet that had not been smoothed. In contrast, alloy no. The aluminum alloy thick plates made of 7c and 7e were insufficient in Mg and Zn contents, so that sufficient strength was not obtained. On the other hand, Alloy No. Since the aluminum alloy thick plates made of 7d and 7f have excessive Mg and Zn contents, coarse intermetallic compounds were formed, and the surface appearance after the alumite treatment was uneven in color.

  In addition, regarding the difference in surface smoothing method, the surface properties due to wrinkles are improved in the case of end milling + hairline processing with proper removal amount or end milling only compared to hairline processing with a small amount of removal. Confirmed to do. In addition, the wrinkles found in the conventional hot-rolled sheet cutting plate are identified as including fine wrinkles of a size that can barely be found with the naked eye, but with only hairline processing. The wrinkles found on the board were clearly visible. Therefore, the effect that the functional defect can be easily distinguished only by the hairline processing was confirmed.

  Furthermore, when only hairline processing is used, the amount of removal is small, so black streaks cannot be prevented. However, when only end milling or end milling + hairline processing is used, the amount of removal is appropriate, preventing black streaks. It was confirmed that it was possible. In addition, since the aluminum alloy thick plate consisting of 7 g does not use the ingot refining agent Ti-B at the time of ingot slab, any surface is not affected by the difference in the surface smoothing method. It was confirmed that black stripes can be prevented from occurring even by the smoothing method.

  As described above, it can be seen that the aluminum alloy thick plate according to the present invention has good flatness and plate thickness accuracy, and surface defects caused by wrinkles and black stripes are suppressed and has good surface properties. It can also be seen that by making the composition of the various alloy components appropriate, properties such as strength can be improved, color unevenness on the surface is suppressed, and surface properties are further improved.

Claims (10)

An aluminum alloy plank coated with a resin film,
The aluminum alloy thick plate, a surface of predetermined length cut aluminum alloy hot-rolled plate, it is smoothed before being coated with a resin film,
The surface flatness is 0.2 mm or less per 1 m in the rolling direction length,
An aluminum alloy thick plate characterized in that the variation in plate thickness is within ± 0.5% of the desired plate thickness.   Mg: 1.5 to 12.0 mass%, Si: 0.7 mass% or less, Fe: 0.8 mass% or less, Cu: 0.6 mass% or less, Mn: 1.0 mass% % Or less, Cr: 0.5% by mass or less, Zn: 0.4% by mass or less, Ti: 0.1% by mass or less, aluminum alloy containing the balance of Al and inevitable impurities. The aluminum alloy thick plate according to claim 1, wherein   Mn: 0.3 to 1.6% by mass, Si: 0.7% by mass or less, Fe: 0.8% by mass or less, Cu: 0.5% by mass or less, Mg: 1.5% by mass % Or less, Cr: 0.3% by mass or less, Zn: 0.4% by mass or less, Ti: 0.1% by mass or less, and an aluminum alloy containing the balance of Al and inevitable impurities. The aluminum alloy thick plate according to claim 1, wherein   Mg: 0.3 to 1.5% by mass, Si: 0.2 to 1.6% by mass, Fe: 0.8% by mass or less, Cu: 1.0% by mass or less, Mn: 0 .6% by mass or less, Cr: 0.5% by mass or less, Zn: 0.4% by mass or less, Ti: 0.1% by mass or less, and the balance is made of Al and inevitable impurities The aluminum alloy thick plate according to claim 1, which is made of an aluminum alloy.   Zn: 3.0 to 9.0% by mass, Mg: 0.4 to 4.0% by mass, Si: 0.7% by mass or less, Fe: 0.8% by mass or less, Cu: 3 0.0% by mass or less, Mn: 0.8% by mass or less, Cr: 0.5% by mass or less, Ti: 0.1% by mass or less, Zr: 0.25% by mass or less, The aluminum alloy thick plate according to claim 1, wherein the balance is made of an aluminum alloy made of Al and inevitable impurities. It is a manufacturing method of the aluminum alloy thick board according to claim 1,
A melting step of melting an aluminum alloy to form a molten aluminum alloy, a dehydrogenation step of removing hydrogen gas from the molten aluminum alloy, a filtration step of removing inclusions from the molten aluminum alloy from which the hydrogen gas has been removed, A casting process for producing an ingot by casting the molten aluminum alloy from which the inclusions have been removed, a hot rolling process for producing a hot-rolled sheet by hot rolling the ingot to a predetermined thickness, and Cutting the hot rolled plate to have a predetermined rolling direction length and width, and a smoothing step of smoothing the surface of the cut hot rolled plate,
In the smoothing treatment step, the removal thickness of the surface of the hot rolled plate is 2 to 5 mm per side, and the method for producing an aluminum alloy thick plate according to claim 1,   The aluminum alloy thick plate according to claim 6, wherein the ingot is subjected to a soaking process by heat treatment at 400 ° C. or more and less than a melting point of the aluminum alloy for 1 hour or more before the hot rolling process. Production method.   The method for producing an aluminum alloy thick plate according to claim 6 or 7, wherein an annealing step of annealing the cut hot-rolled plate is performed before the smoothing treatment step.   9. The aluminum alloy thick plate according to claim 6, wherein the smoothing treatment step is performed by any one or more of a cutting method, a grinding method, and a polishing method. Production method.   The said aluminum alloy is the aluminum alloy of any one of Claim 2 thru | or 5, The manufacturing method of the aluminum alloy thick board of any one of Claim 6 thru | or 9 characterized by the above-mentioned. .

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