KR101251235B1 - Aluminum alloy plate and process for producing the same - Google Patents

Abstract

The present invention provides an aluminum alloy thick plate suitable for a semiconductor-related device member, which has good plate thickness precision and flatness, and which can suppress surface defects and a method of manufacturing the same. The aluminum alloy of the predetermined component is dissolved (dissolving step), hydrogen gas and inclusions are removed (dehydrogenation step, filtration step), and cast to form an ingot (casting step). This ingot is homogenized by heat treatment (homogeneous treatment step) as needed, hot rolled to a predetermined thickness (hot rolling step), cut (cutting step), and smoothed to complete the surface (smoothing treatment step). Moreover, you may perform heat processing (annealing process), such as a distortion correction (calibration process) and annealing as needed. As for the obtained aluminum alloy thick plate, the flatness of the surface is 0.2 mm or less per 1 m of rolling direction length, and plate | board thickness nonuniformity is within ± 0.5% of a desired plate | board thickness.

Description

Aluminum alloy plate and its manufacturing method {ALUMINUM ALLOY PLATE AND PROCESS FOR PRODUCING THE SAME}

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

Generally, aluminum alloy material is used for various uses, such as an electric-electronic component, its manufacturing apparatus, household goods, and a mechanical component, in addition to semiconductor related apparatuses, such as a base substrate, a conveying apparatus, and a chamber for vacuum apparatuses. In addition, steel and cast steel are used for mass production as a mold material used for a press die, but zinc alloy casting material, aluminum alloy casting material, etc. are used for test production. Moreover, in recent years, from the tendency of the small product quantity reduction, whole body materials, such as a rolled material or a forging material, of aluminum alloy are spread | distributed for the production of small and medium quantities.

Among them, the rolled material of the aluminum alloy is manufactured through the annealing step (S600) from the melting step (S101), for example, as shown in FIG. 2, and then inspected for warping, plate thickness, and surface scratches (for example, Japanese patent). After the publication (see Japanese Patent Application Laid-Open No. 2006-281381), a treatment of covering the rolled front and back surface with a resin film made of vinyl chloride or polyethylene (for example, Kobe Steel Technology Publication / Vol. 52 No. 2, September 2002, registered trademark) : A registered trademark of ALHIGHCE, Furukawa-Sky Aluminum Corp .: HIPLATE and the like is known] (S101 to S900).

The reason why the rolled front and back surfaces are covered with a resin film is that high-precision aluminum alloy plates are often used as parts of precision instruments, and are therefore traded through cut sheet wholesalers with a small size and a small number of people. . That is, in a printing wholesaler, saw cutting is carried out to make a small dimension of dice size for the use of precision instrument parts, and end milling is carried out partially for the vacuum chamber use, and a non-processed part becomes an apparatus exterior material. Therefore, the rolled front and back surfaces of the high precision aluminum alloy thick plate are distributed in the form of a product covered with a resin film for the purpose of preventing the occurrence of scratches during such cutting operations.

The rolled material of this aluminum alloy is normally manufactured by hot rolling an ingot to a predetermined thickness. However, such an aluminum alloy hot rolled sheet is difficult to obtain good sheet thickness precision and flatness (particularly flatness in the rolling direction) because the sheet thickness and flatness are controlled only by the rolling roll. Moreover, since the thick oxide film is formed in the rolling surface at the time of hot rolling, control of the same flatness is difficult. Then, the technique which improves the precision of plate | board thickness by carrying out cold rolling to the rolling reduction rate 5% or less of the grade which does not accumulate distortion after hot rolling is disclosed (for example, refer patent document 1).

Japanese Patent Laid-Open No. 2006-316332 (paragraphs 0027 to 0028)

However, the prior art of the said patent document 1 makes an aluminum alloy material the thin plate of sheet thickness of about 1 mm.

In addition, the above-mentioned surface scratches are not only a beautiful appearance of the product, but also a serious quality defect that impairs the function of the product, which lowers the yield of the product and at the same time, requires a large number of steps to remove the defect and impedes productivity. It is becoming. For example, a customer who uses a small size of a dice may process a purchased product and deliver the product, and then find scratches at the stage where the coated resin film is peeled off at the product delivery site, thereby missing an end customer's sales opportunity or vacuuming. In the chamber application, if the scratches are found in the foundry, they become functional defects, but if the scratches are minute, they cannot be distinguished from the damaged scratches, which takes time for determining the scratch factor, thereby providing an opportunity for sales to the end customers. There is a problem that you miss.

In addition, the level of scratches in question is a problem in recent years because the required level is high, and in the case of a scratch having a depth of about 8 µm or more and a diameter of about 0.1 mm in a circular equivalent diameter, it is a problem to the naked eye. In addition, in the conventional manufacturing method, it is difficult to atomize all the scratches of the above level. In addition, mainly in vacuum chamber use, it is hardly used as the surface of a raw material, and an anodizing process and a plating process are performed in order to improve corrosion resistance and weather resistance. In recent years, even though there is no defect in the original plate, after performing the surface treatment as described above, a black line surface defect of about 3 μm length in the rolling parallel direction is caused by the residual residue after melting of Ti-B which will be described later. This trouble occurs, and this improvement is also urgently needed. In order to meet the customer demands of these surface defects, a high precision aluminum alloy thick plate capable of reliably excluding surface defects caused by this level of surface defects or surface treatments before coating the resin film is desired.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and is an aluminum alloy thick plate capable of suppressing surface defects due to scratches or black lines, while having good sheet thickness precision and flatness that can be produced in semiconductor-related devices such as vacuum chambers. And it aims at providing the manufacturing method.

MEANS TO SOLVE THE PROBLEM In order to solve the said subject, the aluminum alloy thick plate which concerns on this invention is an aluminum alloy thick plate formed by smoothing the surface of an aluminum alloy hot rolled sheet, and the flatness of the surface is 0.2 mm or less per 1m of rolling direction length, The deviation is within ± 0.5% of the desired plate thickness.

In this way, by smoothing the surface (before the resin film coating), by limiting the variation in the flatness and the plate thickness of the surface to a predetermined range, a semiconductor-related device or the like is not performed without thinning such as cold rolling. It can be set as the aluminum alloy material for the product which requires high precision in the shape. It is also possible to control the surface defects due to scratches or black lines.

Preferably, the aluminum alloy thick plate contains 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 mass% or less, Zn: 0.4 mass% or less, Ti: 0.1 mass% or less, 1 or more types are contained, and remainder consists of Al and an unavoidable impurity.

By containing such an element in a concentration within a predetermined range, it is possible to obtain an Al-Mg alloy thick plate having excellent properties such as strength, in addition to plate thickness precision and flatness. In addition to the control of surface defects due to scratches, black lines, or the like, the occurrence of color irregularity on the surface can also be suppressed.

Preferably, the aluminum alloy thick plate contains Mn: 0.3 to 1.6 mass%, 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: 0.1 mass% or less, and remainder consists of an aluminum alloy which consists of Al and an unavoidable impurity.

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, in addition to plate thickness precision and flatness. Moreover, in addition to suppression of the surface defect by a scratch, a dark line, etc., generation | occurrence | production of the surface irregularity can also be suppressed.

Preferably, the aluminum alloy thick plate contains 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, One or more of Cr: 0.5 mass% or less, Zn: 0.4 mass% or less, Ti: 0.1 mass% or less, and the balance consists of aluminum alloy which consists of Al and an unavoidable impurity.

By containing such an element in a concentration within a predetermined range, it is possible to obtain an Al-Mg-Si alloy thick plate excellent in characteristics such as strength, in addition to plate thickness precision and flatness. Moreover, in addition to suppression of the surface defect by a scratch, a dark line, etc., generation | occurrence | production of the surface irregularity can also be suppressed.

Preferably, the aluminum alloy thick plate contains Zn: 3.0 to 9.0 mass%, Mg: 0.4 to 4.0 mass%, Si: 0.7 mass% or less, Fe: 0.8 mass% or less, Cu: 3.0 mass% or less, At least one of 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, and the balance is made of an aluminum alloy composed of Al and unavoidable impurities.

By containing such an element in a concentration within a predetermined range, it is possible to obtain an Al-Zn-Mg alloy thick plate having excellent properties such as strength, in addition to plate thickness precision and flatness. Moreover, in addition to suppression of the surface defect by a scratch, a dark line, etc., generation | occurrence | production of the surface irregularity can also be suppressed.

Moreover, the manufacturing method of the aluminum alloy thick plate which concerns on this invention is a manufacturing method of the aluminum alloy thick plate of Claim 1, The melting process of melt | dissolving an aluminum alloy to make an aluminum alloy molten metal, and removing hydrogen gas from the said aluminum alloy molten metal. A dehydrogenation step, a filtration step of removing inclusions from the aluminum alloy molten metal from which the hydrogen gas has been removed, a casting step of casting the aluminum alloy molten metal from which the inclusions have been removed, and a ingot manufacturing step, and hot rolling of the ingot to a predetermined thickness. Performing a hot rolling step of producing a hot rolled plate, a cutting step of cutting the hot rolled plate to a predetermined rolling direction length and width, and a smoothing process step of smoothing the surface of the cut hot rolled plate, In the said smoothing process process, the removal of the surface of the said hot rolling plate Is a 2㎜ to 5㎜ per one surface.

Thus, by performing the smoothing process on the surface of a hot rolled sheet by predetermined | prescribed removal thickness, plate | board thickness precision and flatness can be improved. In addition, surface defects due to scratches, black lines, or the like can be suppressed.

Preferably, the manufacturing method of the said aluminum alloy thick plate performs the cracking process by heat processing the said ingot for 1 hour or more at 400 degreeC or more below the melting point of the said aluminum alloy before the said hot rolling process.

Thus, by heat-treating an ingot before hot rolling, the structure of an ingot can be refined | homogenized and homogenized.

Preferably, the manufacturing method of the said aluminum alloy thick plate performs an annealing process of annealing the said cut hot rolled board before the said smoothing process process.

Thus, by performing annealing to a hot rolled sheet, the characteristic of a hot rolled sheet can be improved.

Preferably, in the manufacturing method of the said aluminum alloy thick plate, the said smoothing process process is performed by any one or more of a cutting method, the grinding method, and the grinding | polishing method.

By this method, the plate | board thickness precision and flatness of an aluminum alloy thick plate become favorable. In addition, surface defects due to scratches, black lines, or the like can be suppressed.

According to the aluminum alloy thick plate which concerns on this invention, since it becomes a desired plate thickness and a flat thick plate also in the thick plate with few plastic deformations, it becomes suitable for the case of manufacturing in a semiconductor related device etc. which require exact shape. In addition, since surface defects due to scratches, black lines and the like are suppressed, the surface properties of the thick plate are good. Moreover, by using a predetermined aluminum alloy, characteristics such as strength are improved, and occurrence of surface unevenness is suppressed, and the surface properties of the thick plate are further improved.

According to the manufacturing method of the aluminum alloy thick plate which concerns on this invention, the aluminum alloy thick plate which has the said effect can be manufactured efficiently.

1 is a flowchart showing a method for producing an aluminum alloy thick plate according to the present invention;
2 is a flow chart showing an example of a method for producing an aluminum alloy thick plate according to the prior art.

EMBODIMENT OF THE INVENTION Hereinafter, the best form for implementing the aluminum alloy thick plate which concerns on this invention is demonstrated.

[Configuration of Aluminum Alloy Plate]

An aluminum alloy thick plate according to the present invention is an aluminum alloy hot rolled sheet (aluminum alloy hot rolled sheet) having a smooth surface, and the flatness of the surface is 0.2 mm or less per 1 m of rolling direction length, and the variation in the plate thickness is the desired plate thickness. It is within ± 0.5%. In addition, although the aluminum alloy thick plate which concerns on this invention is a board | plate material of 15 mm-200 mm, it does not specifically limit, It can change suitably according to the use of an 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 1m of rolling direction length)

If a member having inferior flatness is used for a member of a semiconductor-related device, particularly an inner member of a chamber for a vacuum apparatus such as a plasma processing apparatus, the degree of vacuum decreases due to the release of adsorption gas from the surface of the member when the vacuum is reduced under high vacuum. . Therefore, time to reach the target vacuum degree is required, and production efficiency falls. Therefore, the flatness of the surface of the aluminum alloy thick plate which concerns on this invention shall be 0.2 mm / m or less. In addition, since the flatness of the surface of a hot rolled sheet is inferior in a rolling direction, let it be per rolling length 1m. Such flatness is adjusted by the smoothing process and correction process in the manufacturing method mentioned later.

(Deviation of plate thickness: within ± 0.5% of the desired plate thickness)

Since the aluminum alloy thick plate which concerns on this invention is manufactured from the product which requires high precision for a shape, such as a member of a semiconductor related device, high precision is also requested | required also for plate | board thickness. In order to respond to this demand, the variation in sheet thickness is within ± 0.5% of the desired sheet thickness. Such sheet thickness precision is adjusted by the smoothing process process in a later manufacturing method.

In addition, as for the aluminum alloy thick plate which concerns on this invention, it is preferable to make the amount of hydrogen gas contained per 100 g of this into 0.2 ml or less, and it is more preferable to set it as 0.1 ml or less. Hydrogen gas is generated from hydrogen in fuel, moisture attached to the earth, and other organic matters. If a lot of hydrogen gas is contained, it may cause pinholes or weaken the strength of the product. In addition, hydrogen accumulates and concentrates at grain boundaries near the surface of the ingot, peeling of the aluminum alloy thick plate caused by blisters and bubbles of the ingot occurs, and appears as a surface defect of the thick plate. Potential defects of the thick plate surface occur. In addition, if such a defect is present in the inner member of the chamber for a vacuum apparatus, the degree of vacuum decreases due to the release of gas atoms that are solid solution to the member when depressurized by high vacuum. Therefore, time to reach the target vacuum degree is required, and production efficiency falls. In order to reduce the amount of hydrogen gas contained in an aluminum alloy thick plate, hydrogen gas is removed from the aluminum alloy molten metal before casting by the dehydrogenation process in the manufacturing method mentioned later.

The concentration of hydrogen gas in the ingot is obtained by, for example, cutting out a sample from an ingot (before cracking treatment) and performing ultrasonic cleaning with alcohol and acetone. The inert gas airflow melting thermal conductivity method [LIS (Light-Metal Industrial Standard) AO6-1993] Can be obtained by The concentration of hydrogen gas in the aluminum alloy thick plate is vacuum heated, for example, by cutting a sample from an aluminum alloy thick plate, immersing in NaOH, removing the surface oxide film with acetic acid, and performing ultrasonic cleaning with alcohol and acetone. It can obtain | require by extraction capacity method (LIS AO6-1993).

The aluminum alloy thick plate according to the present invention may be made of any aluminum alloy, but may be any of Al-Mg alloy, Al-Mn alloy, Al-Mg-Si alloy, and Al-Zn-Mg alloy. From then, the material suitable for the application can be selected. Hereinafter, 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 Base Alloy]

Al-Mg-based alloys according to the present invention, that is, aluminum alloys based on 5000-based Al alloys contain Mg: 1.5 to 12.0 mass%, Si: 0.7 mass% or less, Fe: 0.8 mass% or less, Cu: One or more of 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, and the balance consists of Al and an unavoidable impurity.

(Mg: 1.5-12.0 mass%)

Mg has the effect of improving the strength of the Al-Mg-based alloy. If the Mg content is less than 1.5% by mass, this effect is small. On the other hand, if the Mg content is more than 12.0% by mass, castability is remarkably reduced, making the product impossible. Therefore, when using the Al-Mg type alloy of the said component composition, it is necessary to make Mg content into 12.0 mass%. Therefore, Mg content shall be 1.5-12.0 mass%.

(Si: 0.7 mass% or less)

Si is now an element inevitably contained in an aluminum alloy as an impurity. Si has an effect of improving the strength of the aluminum alloy, but on the other hand, Si is combined with Mn and Fe to produce Al- (Fe)-(Mn) -Si-based intermetallic compounds. When Si content exceeds 0.7 mass%, a coarse intermetallic compound will arise in a ingot, and a stain will be easy to appear in the surface appearance after an alumite process. Therefore, Si content is made into 0.7 mass% or less.

(Fe: 0.8% by mass or less)

Fe is now an element that is inevitably contained in an aluminum alloy as an impurity. Fe has an effect of miniaturizing and stabilizing crystal grains of an aluminum alloy and improving strength. On the other hand, it is associated with Mn and Si at the time of casting, and produces Al-Fe- (Mn)-(Si) type intermetallic compound. When Fe content exceeds 0.8 mass%, a coarse intermetallic compound will arise in an ingot, and it will become easy to produce a stain on the surface appearance after an alumite treatment. Therefore, Fe content shall be 0.8 mass% or less.

(Cu: 0.6 mass% or less)

Cu has an effect of improving the strength by solid solution in the aluminum alloy. The strength for use as the Al-Mg alloy thick plate is sufficiently secured with a Cu content of 0.6% by mass, and the effect is saturated even if it is added in excess of it. Therefore, Cu content is made into 0.6 mass% or less.

(Mn: 1.0 mass% or less)

Mn has an effect of improving the strength by solid solution in the aluminum alloy. On the other hand, when Mn content exceeds 1.0 mass%, a coarse intermetallic compound will arise in an ingot, and a stain will be easy to appear in the surface appearance after an alumite process. Therefore, Mn content is made into 1.0 mass% or less.

(Cr: 0.5 mass% or less)

Cr precipitates as a fine compound at the time of casting or heat treatment, and has an effect of suppressing grain growth. On the other hand, when Cr content exceeds 0.5 mass%, a coarse Al-Cr type intermetallic compound will arise as a primary tablet, and the surface appearance after an alumite process will become easy to produce a stain. Therefore, Cr content is made into 0.5 mass% or less.

(Zn: 0.4 mass% or less)

Zn has the effect of improving the strength of the aluminum alloy. The intensity | strength for using as an Al-Mg type alloy thick plate fully ensures that Zn content is 0.4 mass%, and even if it adds exceeding, an effect is saturated. Therefore, Zn content is made into 0.4 mass% or less.

(Ti: 0.1 mass% or less)

Ti has an effect which refine | miniaturizes the crystal grain of an aluminum alloy. Even if Ti content exceeds 0.1 mass%, the effect is saturated. Therefore, Ti content is made into 0.1 mass% or less.

[Composition of Al-Mn Base Alloy]

Next, each element of Al-Mn type alloy is demonstrated. The Al-Mn-based alloy according to the present invention, that is, the aluminum alloy based on the 3000-based Al alloy contains Mn: 0.3 to 1.6 mass%, 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, and Ti: 0.1 mass% or less are contained, and remainder consists of Al and an unavoidable impurity.

(Mn: 0.3 to 1.6 mass%)

Mn has an effect of improving the strength by solid solution in the aluminum alloy. If the Mn content is less than 0.3% by mass, this effect is small. On the other hand, if the Mn content is more than 1.6% by mass, coarse Al- (Fe) -Mn- (Si) -based intermetallic compounds are formed in the ingot, and the surface after anodizing It becomes easy to be stained in appearance. Therefore, Mn content is made into 0.3-1.6 mass%.

(Mg: 1.5 mass% or less)

Mg has the effect of improving the strength of the aluminum alloy. The strength for use as an Al-Mn-based alloy thick plate is sufficiently secured with a Mg content of 1.5% by mass, and the effect is saturated even if it is added in excess of it. Therefore, Mg content is made into 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 effects of Si, Fe, Cu, Cr, Zn, and Ti are the same as those in the Al-Mg-based alloy, they are omitted.

[Composition of Al-Mg-Si-Based Alloy]

Next, each element of Al-Mg-Si type alloy is demonstrated. The Al-Mg-Si-based alloy according to the present invention, that is, the aluminum alloy based on the 6000-based Al alloy contains Mg: 0.3 to 1.5 mass%, Si: 0.2 to 1.6 mass%, and Fe: 0.8 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 includes Al and unavoidable impurities Is made of.

(Mg: 0.3 to 1.5 mass%)

Mg has the effect of improving the strength of the aluminum alloy, and coexists with Si to form Mg ₂ Si to improve the strength of the aluminum alloy. If the Mg content is less than 0.3% by mass, this effect is small. On the other hand, when Mg content exceeds 1.5 mass%, it may become a characteristic of Al-Mg type (5000 type Al) alloy. Therefore, Mg content is made into 0.3-1.5 mass%.

(Si: 0.2 to 1.6 mass%)

Si has the effect of improving the strength of the aluminum alloy, and coexists with Mg to form Mg ₂ Si to improve the strength of the aluminum alloy. This effect is small when Si content is less than 0.2 mass%. On the other hand, when Si content exceeds 1.6 mass%, a coarse intermetallic compound will arise in an Al-Mg-Si type | system | group alloy, and a stain will be easy to appear in the surface appearance after an alumite process. Therefore, Si content is made into 0.2-1.6 mass%.

(Cu: 1.0 mass% or less)

Although Cu has the effect of improving the strength by solid solution in the aluminum alloy, on the other hand, when the Cu content exceeds 1.0% by mass, the corrosion resistance of the Al-Mg-Si alloy is lowered. Therefore, Cu content is made into 1.0 mass% or less.

(Zn: 0.4 mass% or less)

Although Zn has the effect of improving the strength of the aluminum alloy, on the other hand, when the Zn content exceeds 0.4% by mass, the corrosion resistance of the Al-Mg-Si alloy is lowered. Therefore, Zn content is made into 0.4 mass% or less.

(Fe: 0.8% by mass or less, Mn: 0.6% by mass or less, Cr: 0.5% by mass or less, Ti: 0.1% by mass or less)

The effects of Fe, Mn, Cr, and Ti are the same as those in the Al-Mg-based alloy and are therefore omitted.

[Composition of Al-Zn-Mg Base Alloy]

Next, each element of Al-Zn-Mg type alloy is demonstrated. The Al-Zn-Mg alloy according to the present invention, that is, the aluminum alloy based on the 7000 Al alloy contains Zn: 3.0 to 9.0% by mass, Mg: 0.4 to 4.0% by mass, and Si: 0.7% by mass or less. , Fe: 0.8% by mass or less, Cu: 3.0% 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 balance consists of Al and unavoidable impurities.

(Zn: 3.0 to 9.0 mass%)

Zn has the effect of improving the strength of the aluminum alloy. If the content of Zn is less than 3.0% by mass, this effect is small. On the other hand, if the content of Zn exceeds 9.0% by mass, coarse intermetallic compounds are formed, resulting in staining of the surface appearance after the alumite treatment, or the SCC (stress resistance). Corrosion cracking). Therefore, Zn content is made into 3.0 to 9.0 mass%.

(Mg: 0.4 to 4.0 mass%)

Mg has the effect of improving the strength of the aluminum alloy. If the Mg content is less than 0.4% by mass, this effect is small. On the other hand, if the Mg content is more than 4.0% by mass, coarse intermetallic compounds are formed, resulting in stains on the surface appearance after the alumite treatment, and the SCC (stress corrosion cracking resistance) is easy. This will fall or fall. Therefore, Mg content is made into 0.4-4.0 mass%.

(Cu: 3.0 mass% or less)

Cu has an 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-based alloy is lowered. Therefore, Cu content is made into 3.0 mass% or less.

(Zr: 0.25 mass% or less)

Zr has the effect of making the crystal grains of the aluminum alloy fine and at the same time. On the other hand, when Zr content exceeds 0.25 mass%, a coarse intermetallic compound will generate | occur | produce and a stain will be easy to appear in the surface appearance after an alumite process. Therefore, Zr content is made into 0.25 mass% or less.

(Si: 0.7% by mass or less, Fe: 0.8% 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)

The effects of Si, Fe, Mn, Cr, and Ti are the same as those in the Al-Mg-based alloy and are therefore omitted.

In addition, in any of Al-Mg-based alloys, Al-Mn-based alloys, Al-Mg-Si-based alloys, and Al-Zn-Mg-based alloys, the content of V and B as unavoidable impurities is 0.01% by mass or less, respectively. The back side does not affect the characteristic of the aluminum alloy thick plate of this invention. However, in order to prevent ingot cracking during slab casting, Ti may be added as a micronizing agent composed of B master alloy. However, as described later, when coarse Ti-B particles are dissolved, surface treatment such as anodizing or plating treatment may be performed. Later, black lines may occur. For this reason, although it is preferable not to add B, such as using the refiner of Al-Ti, even if black line | wire generate | occur | produced by addition of B, it removes black line | wire by performing an appropriate smoothing process as mentioned later. It is possible.

[Method for producing aluminum alloy thick plate]

Next, the manufacturing method of the aluminum alloy thick plate which concerns on this invention is demonstrated with reference to drawings. 1 is a flowchart showing a method for producing 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 of any of the above compositions is dissolved to form an aluminum alloy molten metal (dissolution step (S11)), and hydrogen gas and inclusions are removed from the aluminum alloy molten metal, respectively. [Dehydrogenation Step (S12), Filtration Step (S13)]. This aluminum alloy molten metal is cast to produce an ingot (casting step S14), and the ingot is hot rolled to a predetermined thickness to produce a hot rolled plate (hot rolling step S30). Then, the hot rolled sheet is cut (cutting step S50), and the surface is smoothed and finished (smoothing step S70). In addition, before hot rolling, the ingot may be homogenized by heat treatment (cracks treatment step (S20)). In addition, the distortion of the hot rolled sheet may be corrected (calibration step (S40)). Moreover, you may anneal a hot rolled sheet (annealing process (S60)). In addition, the aluminum alloy thick plate manufactured in this way becomes a product form in which the front and back surface was covered with the resin film through an inspection process (S80) and a resin film coating process (S90) after that. In addition, although FIG. 1 makes it finish through a resin film coating process (S90) for convenience, the aluminum alloy thick plate which concerns on this invention is a thing of the step which completed the smoothing process process (S70). Below, the detail of each process is demonstrated.

(Dissolution step)

The dissolution step (S11) is a step of dissolving an aluminum alloy of a predetermined composition to form an aluminum alloy molten metal, and is performed by a known equipment and method.

(Dehydrogenation process)

The dehydrogenation step (S12) is a step of removing hydrogen gas from the aluminum alloy molten metal, which can be suitably removed by performing fluxing, chlorine refining, or inline refining of the aluminum alloy molten metal. . In addition, as a dehydrogenation gas apparatus, it can remove more suitably if it implements using rotary dehydrogenation gas apparatuses, such as sniff (SNIFF), and a porous plug (see Unexamined-Japanese-Patent No. 2002-146447). .

(Filtration process)

Filtration process S13 is a process of removing an oxide and nonmetallic inclusion mainly from the aluminum alloy molten metal with a filtration apparatus. The filtration apparatus is provided with a ceramic tube using, for example, particles of alumina of about 1 mm, and the oxide and inclusions can be removed by passing the molten aluminum alloy therethrough.

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

(Casting process)

Casting process S14 is a casting apparatus comprised, for example, with a water cooling mold, and is a process for manufacturing aluminum alloy ingot by forming and solidifying aluminum alloy molten metal into a predetermined shape, such as a rectangular parallelepiped shape. As the casting method, a semi-continuous casting method can be used. In the semi-continuous casting method, a molten metal of metal is injected from above into a metal water-cooled mold having an open bottom, and solidified metal is continuously taken out from the bottom of the water-cooled mold to obtain an ingot having a predetermined thickness. This semi-continuous casting method may be performed in either the vertical direction or the horizontal direction.

(Cracking process-Treatment temperature: 400 ℃ or higher, less than melting point of aluminum alloy, treatment time: 1 hour or more)

In the crack treatment step (S20), by heat-treating the aluminum alloy ingot, the internal stress is removed, the solute element segregated at the time of casting is homogenized, and the intermetallic compound produced at the time of casting is diffused and dissolved to form a structure. It is a process for homogenization. Heat processing is performed by holding at 400 degreeC or more and the temperature below melting | fusing point of an aluminum alloy, for 1 hour or more in accordance with a conventional method. If the crack treatment temperature is less than 400 ° C, the above effect is insufficient. If the treatment time is less than 1 hour, the solid solution of the intermetallic compound is insufficient and is easy to precipitate. On the other hand, when the cracking 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 dissolved, is likely to cause surface defects of the aluminum alloy thick plate. Therefore, the cracking treatment temperature is 400 ° C or more and less than the melting point of the aluminum alloy, and is performed for 1 hour or more.

(Hot rolling process)

Hot rolling process (S30) is a process of carrying out a hot rolling of an aluminum alloy ingot into a board | plate material (aluminum alloy hot rolled sheet) of predetermined thickness. As a hot rolling method, a reverse type (reversible) hot rolling machine can be used. The aluminum alloy ingot is heated up to a predetermined temperature and pressed down by a reverse hot rolling mill to produce an aluminum alloy hot rolled sheet having a predetermined thickness. The plate thickness (plate thickness of an aluminum alloy hot rolled sheet) in this process is a plate thickness which added the reduction by the smoothing process process (S70) mentioned later with respect to the desired plate thickness of an aluminum alloy thick plate, and is 15 mm-200 mm Degree is preferred.

(Calibration process)

The calibration process S40 is a process of correcting and flattening the distortion caused by hot rolling of an aluminum alloy hot rolled sheet, and is performed by known equipment and methods such as a stretcher and a tension leveler.

(Cutting process)

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

(Annealing process)

Annealing process (S60) is a process of removing an internal stress or making internal structure homogeneous by heat-treating an aluminum alloy thick plate. Moreover, you may perform temper by a solution treatment and an aging treatment. In addition, you may perform this process after the smoothing process process (S70). In addition, as disclosed in, for example, Japanese Unexamined Patent Application Publication No. 1998-115617, the surface flatness can be improved by performing heat treatment.

(Smoothing treatment process)

Smoothing treatment step (S70) is a step of smoothing the surface (rolled surface) of the aluminum alloy hot rolled sheet and adjusting the plate thickness.

Here, the removal thickness of the surface of a hot rolled sheet shall be 2 mm-5 mm per single surface. By making the removal thickness 2 mm or more, the variation in flatness and plate thickness can be adjusted as desired, and surface defects due to scratches can be suppressed.

In addition, as described above, in recent years, even though there is no defect in the original plate, after performing surface treatment such as alumite treatment or plating treatment, a black line surface defect having a length of about 3 μm in the rolling parallel direction occurs. However, as a result of intensive investigation of this cause, the inventors have found that the Ti-B of the ingot cracking prevention and the casting ingot refiner (grain refining agent) is melted in the quench solidification part near the mold of the slab ingot. Followed up. Therefore, the removal thickness is 2 mm or more, so that even if Ti-B of the ingot refiner melts and remains, even if there is a residue, it can be removed. Nothing happens. In addition, the removal thickness is made 5 mm or less from a viewpoint of product ratio and cost performance.

As the smoothing treatment method, cutting methods such as end mill cutting and diamond bite cutting, grinding methods of cutting the surface with curb, etc., polishing methods such as buffing polishing and the like can be used. It is not limited to.

In addition, in the smoothing process S70, after suppressing surface defects caused by flatness, plate thickness variation, scratches, black lines, or the like, the hair line process may be further performed. By performing a hairline process, a rolling mark can be provided to a thick plate surface. As a method of hair line processing, although polishing methods, such as a belt type or a wheel type, are known, you may employ | adopt either method, and as a grinding | polishing nonwoven fabric used for hairline processing, such as a belt type or a wheel type, as an abrasive grain type, It is known to consist of a single substance such as alumina, silicon carbide, zirconia, or such a mixture, and an adhesive such as resin or nicawa. As the number of abrasive grains, relatively coarse # 120 to # 220 may be mentioned. In addition, when using the abrasive nonwoven fabric whose diameter of rotation of a belt or wheel is 400 mm in diameter, it contains lubricating oil of antiflammation, It is preferable to carry out hairline processing at the rotation speed of 1500 rpm or less, but it is limited to these conditions. no.

Moreover, regarding the defect of the surface by a flaw, the magnitude | size of the flaw which a human can visually recognize is 8 micrometers or more in depth, and the magnitude | size of the flaw which is difficult to determine at the time of inspection is also 20 micrometers, but it is 8 micrometers-20 The micrometer depth is indentation caused by foreign matter or roll scratches, and these defects are not inherently functional defects. For this reason, such press-fitting scratches can be made smooth by making the boundary between the smooth portion and the scratches on the surface of the thick plate surface smooth by performing hairline processing (2 μm to 3 μm in the processing zone). There is an effect of facilitating discrimination from normal defects. In addition, neglecting economic efficiency, the effect of the present invention can be obtained by shaving 2 mm or more per single side only by hairline processing.

And the aluminum alloy thick plate manufactured in this way is inspected about distortion, plate | board thickness, surface scratches, etc. by the inspection process (S80) after that, and a front and back surface is a resin film by a resin film coating process (S90). Covered with

Example

As mentioned above, although the best form for implementing this invention was described, the Example which confirmed the effect of this invention is demonstrated concretely in contrast with the comparative example which does not satisfy the requirements of this invention. In addition, this invention is not limited to this Example.

Example 1 Preparation of Test Material

(Al-Mg type alloy)

The aluminum alloy (5k: JIS5052 alloy, 5l: JIS5083 alloy, 5v is free of Ti and B without addition) of the aluminum alloy of the composition No.5a to 5v shown in Table 1 is melted, dehydrogenated, filtered, and then cast to form a plate thickness. 500 mm ingot was produced. The ingot was heated at 500 ° C. for 4 hours and subjected to cracking, followed by hot rolling to produce an aluminum alloy hot rolled sheet having a thickness of about 25 mm and a thickness of about 20 mm. After cutting this aluminum alloy hot-rolled sheet into rolling direction length 2000mm x width 1000mm, the smoothing process was performed to the rolling surface (both sides), and it was set as the aluminum alloy thick plate (cut plate) of thickness 20mm. In addition, about Ti containing, Ti-B master alloy is added in order to prevent ingot cracking. The smoothing process compared the effect by three types of methods, an end mill process, an end mill process + hairline process (by belt type abrasive nonwoven fabric), and a hairline process. In addition, performing an end mill process used the aluminum alloy hot rolled sheet of about 25 mm in thickness, and performing only hairline processing used the aluminum alloy hot rolled sheet of about 20 mm in thickness.

End mill processing was used by modifying the end mill machine (Price) made by WASSER GmbH (a German machine manufacturer, GmbH, Inc.). The rough tip was tungsten carbide, the finish tip was diamond, and the working table was adjusted to be a total of about 2.5 mm / single surface with the amount of the disk input from the zero point.

Specifically, thirty rough tips and two finishing tips were mounted in the vicinity of the circumference of the lower surface of the disk, and after cutting the disk to the workpiece, the disk was rotated and cut in the longitudinal direction of the plate. In addition, since the tip tip ejection amount is mounted so as to slightly project than the rough tip, the finish tip is chased away by cutting the cut surface of the rough tip.

Hair line processing was used by remodeling the aluminum plate buffing grinder made by Nomizu Machine Mfg. Co., Ltd. so that an abrasive nonwoven wheel could be attached to the buffing roll. The wheel is POLITEX (registered trademark) KF wheel MA (roughness 150), outer diameter φ400 mm, lubricating oil impregnation made by KOYO-SHA Co., Ltd., and brown melted alumina as an abrasive grain. And a resin bond used as an adhesive agent] were used.

And the grinding | polishing was performed on the conditions (with oscillate (two round trips)) that a processing stand will be about 3.0 micrometers / one side. In addition, the grinding | polishing stand measures the level | step difference of a test grinding | polishing part by "WYKO NT3300 (surface shape measuring system)" made by Vecoo Instruments Inc. (USA), and measures the depth of the unevenness The measurement was confirmed.

(Al-Mn based alloy)

After dissolving the aluminum alloy (3e is Ti and B no addition) of the composition of alloy No.3a-3e shown in Table 1, performing dehydrogenation and filtration, it casted and produced the ingot of 500 mm of plate | board thickness. The 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 cutting this aluminum alloy hot-rolled sheet in rolling direction length 2000mm x width 1000mm, the smoothing process was performed to the rolling surface (both sides), and it was set as the 20-meter-thick aluminum alloy thick plate (cutting plate). In addition, about Ti containing, Ti-B master alloy is added in order to prevent ingot cracking. The smoothing process compared the effect by three types of methods, an end mill process, an end mill process + hairline process (by belt type abrasive nonwoven fabric), and a hairline process. In addition, performing an end mill process used the aluminum alloy hot rolled sheet of about 25 mm in thickness, and performing only hairline processing used the aluminum alloy hot rolled sheet of about 20 mm in thickness. In addition, the method of end mill processing and hairline processing is the same as that of the said Al-Mg type alloy.

[Table 1]

Example 1: Evaluation

The following evaluation is performed with the obtained aluminum alloy thick plate, and a result is shown to Table 2 and Table 3. Moreover, the aluminum alloy hot rolled sheet (thickness 200mm) which does not perform the smoothing process was also produced and evaluated as the comparative example. In addition, since alloy No. 5n could not be manufactured with the aluminum alloy hot-rolled sheet as mentioned later, since the process and evaluation of subsequent were not performed, it shows in Table 2 and Table with "-".

(Flatness)

Flatness evaluation measured the amount of curvature (flatness) per rolling direction 1m of a test material. The acceptance criteria for flatness were flatness of 0.2 mm / m or less.

(Plate thickness precision)

The plate | board thickness in 6 points of the sum total of the site | part of the inside 200 mm in the width direction was measured using the micrometer from the half corner of the length of the four corners of a test material, and the side of a rolling direction. 6 points All plate | board thickness is the range of 20.0 ± 0.06mm (19.94mm-20.06mm), and since it is excellent in plate | board thickness precision, "◎", 20.0 ± 0.10mm (20.0mm ± 0.5%, 19.90mm-20.10mm) It evaluated as "(circle)" that it was favorable that it was a range of.

(burglar)

The tensile test piece by JIS5 was cut out from the test material. With this test piece, the tensile test by JISZ2241 was performed, and tensile strength and proof strength (0.2% yield strength) were measured. Acceptance criteria of strength alloy No.5a to 5u (Al-Mg based alloy) has a tensile strength of 180N / ㎜ ² or more, the alloy No.3a to 3d (Al-Mn-based alloy) has a tensile strength of 90N / ㎜ ² or more I did.

(Surface appearance)

In order to evaluate the influence on the surface property by the smoothing process, the alumite process was performed to the test material (40 sheets each), and the external appearance of the surface was observed.

An anodized film having a thickness of 10 μm was formed on the surface of the specimen by alumite sulfate treatment (15% sulfuric acid, 20 ° C., current density 2 A / dm ² ). And the surface property by the scratch of the surface and the surface property by the black line were investigated.

<Evaluation of surface properties due to scratches after alumite treatment>

The appearance of this anodized surface was observed, and since there was no one of the 40 cut plates where the scratches were visually determined, the evaluation of the surface properties due to the scratches was very good. One to four of the sheets were said to have a good surface property evaluation due to scratches, and "○" and 5 or more of the 40 cut sheets where the scratches were visually judged to have poor surface properties evaluation due to scratches were "x". Was evaluated.

<Evaluation of Surface Properties by Black Lines after Anodizing>

The black line (not a functional defect) of the above-mentioned anodized surface was observed, and the black line was found to be "○" and the naked eye because the evaluation of the surface properties by the black line was good. Was evaluated as &quot; × &quot; because the evaluation of surface properties by black lines was poor.

Moreover, the surface property by the surface unevenness was also investigated. In addition, since this surface property is only the preferable surface property as this invention to the last, even when this surface property is not satisfied, it is satisfy | filling the surface property by a flaw and a black line about this invention. The minimum purpose of the is to achieve.

<Evaluation of surface properties due to staining after alumite treatment>

The appearance of the alumite-treated surface was observed, and the appearance was uneven, and the surface appearance evaluation by the stain was good. .

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

[Table 2]

[Table 3]

Since the aluminum alloy thick plate which consists of alloy Nos. 5a-5l and 5v had content of an additional element in the appropriate range, and the smoothing process suitable for the surface was given, the strength, flatness, plate | board thickness precision, and surface property were favorable. Moreover, even compared with the aluminum alloy hot rolled sheet which has not performed the smoothing process, sufficient strength and favorable surface property were obtained. On the other hand, since the aluminum alloy thick plate which consists of alloy No. 5m lacks Mg content, intensity | strength was not fully acquired. On the other hand, in the aluminum alloy thick plate made of alloy No. 5n, since the Mg content was excessive, casting cracks occurred and production of test materials was impossible. In the aluminum alloy thick plate composed of alloy Nos. 5o, 5p, 5r, and 5s, since the Si, Fe, Mn, and Cr contents are respectively excessive, coarse intermetallic compounds are formed, and the appearance of the surface after the alumite treatment is stained. did. The aluminum alloy thick plate made of alloy Nos. 5q, 5t, and 5u has a Cu, Zn, and Ti content exceeding an appropriate range, respectively, but the strength and surface properties are compared with those of Alloy Nos. 5f, 5j, 5c, where these elements are within an appropriate range. No improvement in effect was seen.

In addition, about the difference of the method of the surface smoothing process, the surface property by a scratch improves only in the case of the end mill processing + hairline processing or the end mill processing with an appropriate removal amount compared with only the hairline processing with a small removal amount. It was confirmed. In addition, the scratches found by cutting plates of conventional hot-rolled sheets include small scratches that have no problem at all in size that can only be detected with the naked eye, but the scratches found by cutting plates subjected to hairline processing only. Was a scratch that can be clearly identified with the naked eye. Therefore, the effect which is easy to distinguish functional defects only by hairline process was confirmed.

In addition, black hairs cannot be prevented because only a small amount of hairline processing removes the black lines. However, in the case of only end mill processing or end milling + hairline processing, a black line is not generated. It was confirmed that it could prevent. In addition, since the aluminum alloy thick plate which consists of 5v does not use Ti-B of the ingot refiner at the time of slab ingot, it is not affected by the difference of the method of the surface smoothing process, and it is black in any method of the surface smoothing process. It was confirmed that line generation can be prevented.

Since the aluminum alloy thick plate which consists of alloy No.3a, 3b, 3e had content of an additional element in the appropriate range, and the smoothing process suitable for the surface was given, the strength, flatness, plate | board thickness precision, and surface property were favorable. Moreover, even compared with the aluminum alloy hot rolled sheet which did not perform the smoothing process, sufficient strength and favorable surface property were obtained. On the other hand, since the aluminum alloy thick plate which consists of alloy No. 3c lacks Mn content, strength was not fully acquired. On the other hand, in the aluminum alloy thick plate made of alloy No. 3d, a coarse intermetallic compound was formed because the Mn content was excessive, resulting in uneven appearance of the surface after the alumite treatment.

In addition, about the difference of the method of the surface smoothing process, it is the case that end surface processing + hairline processing, or end mill processing with only a moderate removal amount compared with only hairline processing with a small removal amount improves the surface property by a scratch. Confirmed. In addition, the scratches found in the cutting board of the conventional hot rolled sheet are determined to include small scratches that have no problem at all in size that can be found with the naked eye. Was a scratch that can be clearly identified with the naked eye. Therefore, the effect which is easy to distinguish functional defects only by hairline process was confirmed.

In addition, black hairs cannot be prevented because only a small amount of hairline processing removes the black lines. However, black hairs can be prevented because only a proper amount of removal is appropriate for end mill processing or end milling + hairline processing. It was confirmed that it could be done. In addition, since the aluminum alloy thick plate which consists of 3e does not use Ti-B of the ingot refiner at the time of slab ingot, it does not affect the difference of the method of the surface smoothing process, and it is black in any method of the surface smoothing process. It was confirmed that line generation can be prevented.

As for the aluminum alloy hot rolled sheet which did not perform the smoothing process, the process distortion accumulate | stored and the state bent in the rolling direction was large, and flatness was unsatisfactory. In addition, the sheet thickness precision was often slightly inferior to that of the aluminum alloy thick plate of the same composition. In addition, the surface properties due to scratches and black lines were poor. In addition, evaluation of the value of the flatness only of hairline processing and the plate thickness precision of a cut board was substantially the same as the evaluation of the value of the flatness of an aluminum hot rolled sheet (without the smoothing process), and the plate thickness precision of a cut plate (processing cost At 2 micrometers-3 micrometers, since the accumulated processing distortion is not reduced, the state bent in the rolling direction is large, and flatness is poor).

Example 2 Test Material Preparation

(Al-Mg-Si alloy)

The aluminum alloy of the composition of alloy No.6a shown to Table 4-6g was melt | dissolved, and after performing dehydrogenation process and filtration, it casted and produced the ingot of plate | board thickness 500mm. The 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 cutting this aluminum alloy hot-rolled sheet in rolling direction length 2000mm x width 1000mm, the rolling surface (both sides) was smoothed and it was set as the thickness 20mm aluminum alloy thick plate (cut plate). In addition, about Ti containing, Ti-B master alloy is added in order to prevent ingot cracking. The smoothing process compared the effect by three types of methods, an end mill process, an end mill process + hairline process (by belt type abrasive nonwoven fabric), and a hairline process. In addition, performing an end mill process used the aluminum alloy hot rolled sheet of about 25 mm in thickness, and performing only hairline processing used the aluminum alloy hot rolled sheet of about 20 mm in thickness. In addition, the method of end mill processing and hairline processing is the same as that of the said Al-Mg type alloy. Furthermore, the obtained aluminum alloy thick plate was solution-processed at 520 degreeC, and the aging process for 8 hours was performed at 175 degreeC.

(Al-Zn-Mg based alloy)

After dissolving the aluminum alloy of the composition of alloy Nos. 7a-7g shown in Table 4, performing dehydrogenation process, and filtration, it casted and produced the ingot of plate | board thickness 500mm. The 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 cutting this aluminum alloy hot-rolled sheet in rolling direction length 2000mm x width 1000mm, the smoothing process was performed to the rolling surface (both sides), and it was set as the thickness 20mm aluminum alloy thick plate (cutting plate). In addition, about Ti containing, Ti-B master alloy is added in order to prevent ingot cracking. The smoothing process compared the effect by three types of methods, an end mill process, an end mill process + hairline process (by belt type abrasive nonwoven fabric), and a hairline process. In addition, performing an end mill process used the aluminum alloy hot rolled sheet of about 25 mm in thickness, and performing only hairline processing used the aluminum alloy hot rolled sheet of about 20 mm in thickness. In addition, the method of end mill processing and hairline processing is the same as that of the said Al-Mg type alloy. Furthermore, the obtained aluminum alloy thick plate was solution-processed at 470 degreeC, and the aging process for 48 hours was performed at 120 degreeC.

[Table 4]

Example 2: Evaluation

In the obtained aluminum alloy thick plate, strength and surface properties were evaluated 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 200mm) which does not perform the smoothing process was also produced, the solution treatment and the aging treatment were performed on the same conditions, and it evaluated as the comparative example. The acceptance criteria for the strength is that alloy Nos. 6a to 6g (Al-Mg-Si-based alloy) have a tensile strength of 200N / mm ² or more, and alloys No. 7a to 7g (Al-Zn-Mg-based alloy) have a tensile strength of 250N. / Mm ² or more.

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

[Table 5]

TABLE 6

As for the aluminum alloy thick plate which consists of alloy No.6a, 6b, 6g, since content of the additional element exists in the appropriate range, and the smoothing process suitable for the surface was given, the strength and surface property were favorable. Moreover, even compared with the aluminum alloy hot rolled sheet which did not perform the smoothing process, sufficient strength and favorable surface property were obtained. On the other hand, since the aluminum alloy thick plate which consists of alloy No.6c and 6e lacks Si, Mg content, respectively, strength could not be fully acquired. On the other hand, in the aluminum alloy thick plate made of alloy No. 6d, since the Si content was excessive, coarse intermetallic compounds were formed, causing stains on the appearance of the surface after the alumite treatment. Moreover, since the aluminum alloy thick plate which consists of alloy No. 6f has excessive Mg content, and became the characteristic of Al-Mg type | system | group (5000 type | system | group Al) alloy, the strength improvement effect by a solution treatment and an aging treatment is not acquired. The strength decreased as compared with Alloy Nos. 6a and 6b in which the Mg content was in the proper range.

In addition, about the difference of the method of the surface smoothing process, it is the case that end surface processing + hairline processing, or end mill processing with only a moderate removal amount compared with only hairline processing with a small removal amount improves the surface property by a scratch. Confirmed. In addition, the scratches found by cutting plates of conventional hot-rolled sheets include small scratches that have no problem at all in size that can only be detected with the naked eye, but the scratches found by cutting plates subjected to hairline processing only. Was a scratch that can be clearly identified with the naked eye. Therefore, the effect which was easy to distinguish functional defects only by hairline process was confirmed.

In addition, black hairs cannot be prevented because only a small amount of hairline processing removes them.However, black hairs can be prevented because of a proper removal amount for end milling or end milling + hairline processing only. It was confirmed. In addition, since the aluminum alloy thick plate which consists of 6 g does not use Ti-B of the ingot refiner at the time of slab ingot, it does not affect the difference of the method of the surface smoothing process, and it is black in any method of the surface smoothing process. It was confirmed that line generation can be prevented.

Since the aluminum alloy thick plate which consists of alloy No.7a, 7b, and 7g had content of an additional element in the appropriate range, and the smoothing process suitable for the surface was given, the strength and surface property were favorable. Moreover, even compared with the aluminum alloy hot rolled sheet which did not perform the smoothing process, sufficient strength and favorable surface property were obtained. On the other hand, since the aluminum alloy thick plates which consist of alloy No.7c and 7e lack Mg and Zn content, respectively, strength was not fully acquired. On the other hand, in the aluminum alloy thick plate made of alloy Nos. 7d and 7f, the coarse intermetallic compound was formed because the Mg and Zn contents were respectively excessive, resulting in uneven appearance of the surface after the alumite treatment.

In addition, about the difference of the method of the surface smoothing process, compared with only hairline processing with a small removal amount, the surface property by a flaw improves only in the case of the end milling + hairline processing or the end milling processing with an appropriate removal amount. It was confirmed. In addition, the scratches found by cutting plates of conventional hot-rolled sheets include small scratches that have no problem at all in size that can only be detected with the naked eye, but the scratches found by cutting plates subjected to hairline processing only. Was a scratch that can be clearly identified with the naked eye. Therefore, the effect which was easy to distinguish functional defects only by hairline process was confirmed.

In addition, in the case of only hairline processing, since the removal amount is small, black line generation cannot be prevented, but only in the end mill processing or in the case of the end mill processing + hairline processing, since the removal amount is appropriate, black line generation is prevented. It was confirmed that it could prevent. In addition, since the aluminum alloy thick plate which consists of 7 g does not use Ti-B of the ingot refiner at the time of slab ingot, it does not affect the difference of the method of the surface smoothing process, and it is black in any method of the surface smoothing process. It was confirmed that line generation can be prevented.

 As described above, it is understood that the aluminum alloy thick plate according to the present invention has good flatness and plate thickness precision, and surface defects due to scratches and black lines are suppressed and have good surface properties. In addition, by appropriately constituting the component composition of various alloys, it can be seen that characteristics such as strength can be improved, and unevenness of the surface can be suppressed, resulting in better surface properties.

Claims (10)

In the aluminum alloy thick plate formed by smoothing the surface of the aluminum alloy hot rolled sheet,
The flatness of the surface is 0.2 mm or less per 1 m of rolling direction length,
Deviation of the plate thickness is within ± 0.5% of the desired plate thickness
Aluminum alloy plates. The method of claim 1,
Mg: 1.5-12.0 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 mass% or less, Zn: 0.4 It is characterized by containing at least one of mass% or less and Ti: 0.1 mass% or less, the remainder being made of an aluminum alloy composed of Al and inevitable impurities.
Aluminum alloy plates. The method of claim 1,
Mn: 0.3-1.6 mass%, 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 It is characterized by containing at least one of mass% or less and Ti: 0.1 mass% or less, the balance being made of an aluminum alloy composed of Al and unavoidable impurities.
Aluminum alloy plates. The method of claim 1,
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: It is characterized by containing at least one of 0.4% by mass or less and Ti: 0.1% by mass or less, the balance being made of an aluminum alloy composed of Al and unavoidable impurities.
Aluminum alloy plates. The method of claim 1,
Zn: 3.0-9.0 mass%, Mg: 0.4-4.0 mass%, 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: 0.25 mass% or less, and remainder consists of aluminum alloy which consists of Al and an unavoidable impurity, It is characterized by the above-mentioned.
Aluminum alloy plates. In the manufacturing method of the aluminum alloy thick plate of Claim 1,
A dissolution step of dissolving an aluminum alloy into an aluminum alloy melt, a dehydrogenation step of removing hydrogen gas from the aluminum alloy melt, a filtration step of removing inclusions from the aluminum alloy melt from which the hydrogen gas has been removed, and the inclusions are removed A casting process of casting the molten aluminum alloy molten metal to produce an ingot, a hot rolling process of hot rolling the ingot to a predetermined thickness to produce a hot rolled plate, and cutting the hot rolled plate to a predetermined length and width in a predetermined rolling direction. And a smoothing treatment step of smoothing the surface of the cut hot rolled sheet,
In the said smoothing process, the removal thickness of the surface of the said hot rolled sheet is 2 mm-5 mm per single surface, It is characterized by the above-mentioned.
Method for producing aluminum alloy thick plates. The method according to claim 6,
Before the hot rolling step, the ingot is subjected to a crack treatment step by heat treatment for at least one hour at 400 ° C. or more and less than the melting point of the aluminum alloy.
Method for producing aluminum alloy thick plates. The method according to claim 6,
An annealing step of annealing the cut hot rolled plate is performed before the smoothing treatment step.
Method for producing aluminum alloy thick plates. The method according to claim 6,
The smoothing treatment step is performed by any one or more of a cutting method, a grinding method and a polishing method, characterized in that
Method for producing aluminum alloy thick plates. The method according to claim 6,
The aluminum alloy is the aluminum alloy according to any one of claims 2 to 5
Method for producing aluminum alloy thick plates.

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