TW200536946A - Method for producing Al-Mg-Si alloy excellent in bake-hardenability and hemmability - Google Patents

Abstract

This invention is to provide a method for producing an aluminum alloy plate excellent in bake-hardenability and hemmability at a low cost by using a very short production process. A method for producing an aluminum alloy plate, having a chemical composition, in wt%, of Mg: 0.30 to 1.00%, Si: 0.30 to 1.20%, Fe: 0.05 to 0.50%, Mn: 0.05 to 0.50%, Ti: 0.005 to 0.10%, optionally Cu: 0.05 to 0.70% and Zr: 0.05 to 0.40%, and the balance Al and inevitable impurities, comprises casting the alloy melt into a slab having a thickness of 5 to 15 mm by the twin belt casting method with a cooling rate of 40 to 150 DEG C/s at 1/4 of the thickness of the slab, winding up the coil, subjecting the coil to a homogenizing treatment, cooling the resultant coil to a temperature of 250 DEG C or lower with a cooling rate of 500 DEG C/hr or more, followed by cold rolling, and solution treatment of the resulting product.

Description

200536946 (1) IX. Description of the invention [Technical field to which the invention belongs] The present invention relates to: continuous casting of aluminum-magnesium-silicon alloys to cast thin blanks, homogenizing treatments, cold rolling, and corresponding measures It is necessary to use a continuous annealing furnace to perform solution heat treatment to obtain a method for manufacturing an aluminum alloy plate having excellent edge workability and high age hardening. According to this method, compared with the conventional technology, it is possible to manufacture the rolls of Ming-Mg-Sand-based alloys that are suitable for forming processes such as bending, stamping, and the like of automobile parts and home appliances at a lower cost. sheet. [Prior art] The aluminum-magnesium-silicon alloy has the characteristic that the strength will increase when heated when it is subjected to coating or the like after forming. Therefore, it is very suitable for applications such as automobile panels. In addition, in order to reduce costs due to improvement in productivity, it has been proposed to manufacture the alloy plate by a continuous casting roll method. For example, as disclosed in Japanese Patent Application Laid-Open No. 62-207 8 51, it will contain sand: 0 · 4 ~ 2 · 5%, magnesium: 0 · 1 ~ 1.2%, and contain copper: 1 · 5. % Or less, zinc: 2.5% or less, chromium: 0.3% or less, manganese 0.6% or less, chromium: 0.3% or less, one or two or more of the four elements are melted The aluminum alloy is 'continuously cast into a blank plate with a thickness of 3 to 15 mm' and then 'cold-rolled', and then subjected to melt heat treatment and quenching treatment to obtain: The maximum amount of intermetallic compounds in the matrix structure An aluminum alloy plate for forming processing having a size of 5 μm or less is a feature and a manufacturing method thereof. -5- 200536946 (2) Japanese Unexamined Patent Publication No. 1 0- 1 1 02 3 2 discloses that "containing silicon: 0.2 to 3.0 ° / 〇, magnesium: 0.2 to 3.0% as essential elements" and Contains four elements of manganese: 0 · 〇1 ~ 0 · 5%, chromium: 〇1 ~ 0.5%, wrong: 0.0 1 ~ 0 · 5%, titanium: 0.0 0 1 ~ 0 · 5%, four elements One or two or more of them, and one or two or more of the three elements consisting of copper: 0 to 2.5%, tin ·· 〇 ~ 〇 · 2%, zinc: 〇 ~ 2.0%, and The iron content is limited to less than 1.0%, and the rest is a direct-cast roll sheet of aluminum alloy composed of aluminum and unavoidable impurities. The aluminum-magnesium-silicon alloy sheet after cold rolling is characterized by: The maximum crystal grain size of the metal structure of the alloy plate is 100 μm or less, and the maximum length of the continuous Mg2Si compound in the surface layer portion is 50 μm or less. In addition, as disclosed in Japanese Patent Application Laid-Open No. 2 0 1-2 6 2 2 6 4, it will contain Shi Xi: 0 · 1 to 2.0%, magnesium: 0 · 1 to 2.0%, and iron: 0 · 1 to 1 · 5% or more containing copper: 2.0% or less, chromium: 0.3% or less, manganese: hafnium · 0% or less, zirconium: 0.3% or less, vanadium: 0.3% or less, titanium: 0.3% or less, Zinc: 1.5% or less, silver: 0.2% or less, one or more of eight elements, an aluminum-magnesium-silicon alloy sheet having excellent toughness and flexibility, which is characterized by: The maximum size of the intermetallic compound of the aluminum alloy plate is 5 μm or less, the maximum aspect ratio is 5 or less, and the average crystal grain size is 30 μm or less. [Patent Document 1] Here, Patent Document 1 refers to: Japanese special Kaizhao 6 2-2 0 7 8 5 1. [Patent Document 2] -6- 200536946 (3) Here, Patent Document 2 refers to Japanese Patent Publication No. 10-1 10232. [Patent Document 3] Here, Patent Document 3 refers to Japanese Patent Publication No. 200 1 -2 62264. [Summary of the Invention] [Problems to be Solved by the Invention] An alloy plate used as an outer panel of a body plate for an automobile is required to have excellent edge workability and baking hardenability. Therefore, an aluminum-magnesium-silicon alloy sheet that has excellent flexibility and age-hardens when heated, meets this requirement. However, the aluminum plate produced by continuous casting and rolling has the disadvantages of poor edge workability and insufficient baking hardenability after painting. Therefore, the technical problem of the present invention is: how to do it can be produced at low cost: it can suppress the G · P band (z 〇ne) crystallized out during natural aging hardening at room temperature, and apply It can quickly crystallize the reinforced phase during packaging, heating, and baking to obtain high baking hardening characteristics, and at the same time, it is rich in flexibility for forming-sand-sand alloy plates. [Means for Solving the Problems] In order to achieve the above object, the present invention proposes the following solutions. A double-belt casting machine is used to continuously cast the aluminum-magnesium-silicon alloy thin blank sheet. Then the cast thin blank sheet is directly wound into a strip roll. For this strip roll, 200536946 (4) under proper conditions Homogenization treatment is performed, and after cold rolling, if necessary, the melt heat treatment performed by a continuous annealing furnace is added to separate the compounds, thereby improving edge processability and greatly reducing Process. In addition, microsegregation is reduced by the homogenization treatment, and the cooling rate after the homogenization treatment is accelerated to suppress the precipitation of M g2 Si during cooling, so that the bake hardenability and edge processing after the final annealing can be obtained. Aluminum sheet for automotive body with excellent properties. In order to solve the above-mentioned problems, the method for manufacturing an aluminum alloy sheet of the present invention is characterized in that after the thin blank sheet is coiled, homogenization treatment is performed, cold rolling is performed, and then melt heat treatment is performed. Specifically, it is a method for manufacturing an A1-Mg-Si alloy plate having excellent baking hardenability and edge workability as described in claim 1, characterized in that it will contain magnesium: 0.30 ~ 1.OOwt%, silicon: 0.30 to 1.20wt%, iron: 0.05 to 0.50wt%, ferrite: 0.05 to 0.50wt%, and titanium ... 0.0 0 5 to 0.10wt ° / 〇, or copper: 0.05 ~ 0.70wt ° / 〇 or zirconium · 0.50 ~ 0.40wt% of one or more of them, the rest is a molten alloy composed of aluminum and unavoidable impurities, using a double-belt casting method to 1/4 of the thickness of the blank The cooling rate is 40 ~ 150 t: / s. The blank with a thickness of 5 ~ 15 mm is casted, and then rolled into an aluminum alloy strip, and then homogenized. The cooling rate should be at least 25 ° C or lower, followed by cold rolling and then melt heat treatment (the invention described in claim 1). In the manufacturing method described above, the homogenization treatment is performed by using a stepwise annealing furnace at a temperature rising rate of 30 t / hour or higher to 5 2 0 to 5 8 (TC, and maintained at the temperature of 2 to 24). An hour is appropriate (please refer to the invention described in claim 2 in 200536946 (5).) The above-mentioned melt heat treatment is performed by using a continuous annealing furnace at a heating rate of 10 ° C / sec or higher to 5 3 0 to 5 60 ° C, and it is preferable to maintain the temperature within 30 seconds (the invention described in claim 3). In addition, in the invention described in claim 3 above, it may be performed after the melt heat treatment. It is cooled to room temperature at a rate of 10 t: / s or more. 'Then, a continuous annealing furnace is used to perform a recovery process maintained at a temperature of 260 to 300 ° C for 30 seconds or less, at 10 ° C / Cooling rate of more than seconds to room temperature (the invention described in claim 4). Alternatively, in the invention described in claim 3 above, after the melt heat treatment, the temperature may be reduced to 10 ° C / Cooling speed above 2 seconds to water cooling below 250 ° C, and then using air to It is cooled to 60 to 100 ° C at a cooling rate of 1 to 20 ° C / second, and then rolled up, and then subjected to preliminary aging treatment (the invention described in claim 5) until it is cooled to room temperature. Or, In the invention described in claim 3, after the above-mentioned melt heat treatment, the temperature may be cooled to room temperature at a rate of 10 ° C / sec or more. Then, the continuous annealing furnace is used to perform the cooling at 2 6 0 to 3 0. 0 t: The temperature is maintained within 30 seconds of recovery under the state of temperature, and it is cooled to 60 to 100 ° C at a cooling rate of 1 ° C / second or more, and then rolled up and then cooled to room temperature. The preliminary aging treatment (invention according to claim 6). [Effects of the Invention] According to the method for producing an aluminum alloy plate of the present invention, an aluminum alloy plate having excellent baking hardenability and edge workability can be obtained. In addition, the manufacturing method-9-200536946 (6) has an extremely short manufacturing process, and an aluminum alloy plate can be obtained at a low cost. [Embodiment] [Embodiment of the Invention] The present invention relates to an aluminum-magnesium-silicon alloy A method for manufacturing a rolled plate, which is characterized by using a double-belt casting After casting into a thin blank, it is directly rolled into a strip, and the strip is subjected to a homogenization treatment, followed by cold rolling, and then a melt heat treatment. The present invention utilizes a molten alloy composed of the above components. Double-belt casting method, with a cooling rate of 1/4 of the thickness of the slab, 40 ~ 150 ° C / s, casting a slab of 5 ~ 15 mm in thickness, and then winding it into a bark After the alloy strip is rolled, it is subjected to a homogenization treatment, cooled at a cooling rate of 500 ° C./hour or higher to at least 250,000 t, and then cold-rolled, followed by melt heat treatment. The so-called "dual-belt casting method" is a method in which molten alloy is injected between rotating belts that face each other and are being water-cooled, and the molten alloy is solidified by cooling from the belt surface to be cast into a thin blank. In the present invention, a green sheet with a thickness of 5 to 15 mm is cast using a dual-belt casting method. If the thickness of the slab is more than 5 mm, it is difficult to roll the thin slab into a roll. If the thickness of the slab is less than 5 mm, the productivity will be reduced, and the casting of the thin slab will be difficult. Become difficult. This method of using a dual-belt casting method to cast a slab with a thickness of 5 to 15 mm m can control the cooling rate at a thickness of 1/4 of the slab to 40 to 150 ° C / sec. The cooling rate was calculated by observing the microstructure 200536946 at a thickness of 1/4 of the embryonic plate, and measuring the D A S (dendritic crystal spacing; Dendrite Arm Spacing) using the intersection method. If the cooling rate is less than 40 ° C / sec, the cast structure generated during solidification at the center of the blank will become coarse and the workability of the edge will be reduced. If the cooling rate exceeds 150 ° C / sec The aluminum-iron-silicon crystals and aluminum- (iron-manganese) -silicon crystals will have a size of 1 μm or less, and the size of the recrystallized grains will become coarse and become 30 μm or more. After winding the thin blank, the metal strip is rolled under appropriate conditions and subjected to homogenization treatment, so that aluminum-iron-silicon crystals, aluminum- (iron • Manganese) -silicon crystals are separated, and the edge processability can be improved. In addition, it is possible to obtain a thin slab in a state where the finer Mg2 Si crystals remaining in the cast structure are completely solidified in the matrix structure, and the effect of the melt treatment after the cold rolling process can be improved. . The reason why the cooling after the homogenization treatment is set to be: at a cooling rate of 500 ° C / hour or more to at least 250 ° C or less, is to suppress the coarse Mg 2 as much as possible. S i crystallizes out, to make the consideration that some mongolian and sand are supersaturated and solidified in matri X organization. After winding the thin blank, the metal strip coil is inserted into a split annealing furnace at a temperature increasing rate of 30 ° C / hour or higher, and the temperature is increased to 5 2 0 to 5 8 0 ° C. After homogenization for 2 to 24 hours, the metal strip coil can be taken out of the fractional annealing furnace and forcedly cooled to room temperature with air at a cooling rate of 500 ° C / hour or more. Its -11-200536946 (8) Cooling method ’For example, on the one hand, the metal strip roll can be loosened and straightened, and on the other hand, it can be cooled by a fan. The reason why the heating rate in the homogenization process after the coiling of the thin slab is heated up to the temperature of the homogenization process is set to a temperature increase rate of 30 ° C / hour or more. If it is less than 30 ° C / hour, it will take more than 16 hours to reach the predetermined homogenization temperature. In this case, the manufacturing cost will be increased. The reason why the homogenization temperature should be set in the range of 5 2 0 to 5 80 ° C is because the temperature is less than 52 (TC, aluminum-iron-silicon precipitates, aluminum- (iron-manganese ) -The separation of silicon crystals is not enough to make the Mg 2 S i crystallized during casting fully solidified in the altar structure, but if the temperature exceeds 5 80 ° C, the low melting point metal will It will melt and cause a meltdown phenomenon. The reason why the homogenization treatment time should be set in the range of 2 to 24 hours is because if the time is less than 2 hours, aluminum-iron-silicon crystals and aluminum- (Iron • Manganese)-The separation of silicon crystals is not sufficient, and Mg2Si crystallized during casting cannot be fully solidified in the altar structure. If the time exceeds 24 hours, M g 2 S i is fully solidified in Al Qaeda, and manganese and silicon tend to be saturated, which will lead to increased costs. This metal strip coil is further cold-rolled and then melt-processed, which is one of its characteristics. This type of melt treatment is usually carried out in a continuous annealing furnace (CAL) as The so-called continuous annealing furnace (CAL) is a facility that continuously melts metal strips in 200536946 (9). It is characterized by: an induction heating device for heat treatment and a water tank for water cooling And air-cooled air nozzles, etc. As for the melt treatment, the continuous annealing furnace is heated to 5 3 0 ~ 56 (TC) at a temperature increase rate of 10 ° c / sec or more, and maintained for 30 seconds. In the melt treatment, the reason why the heating rate during the homogenization process to the temperature of the homogenization process is set to be: a reason why the temperature increase rate is 10 ° c / hour or more. If the heating rate does not exceed 10 ° C / hour or more, the feeding speed of the metal strip coil will become extremely slow, and as a result, the processing time will be longer, which will increase the manufacturing cost. The reason why the temperature of the chemical treatment is set in the range of 5 3 0 to 5 60 ° C is that if the temperature does not reach 5 3 (TC, M g2 S crystallized during casting or cooling after the homogenization treatment cannot be achieved). i fully It melts in Al Qaeda, but if the temperature exceeds 5 60 ° C, the low melting point metal will melt and cause the phenomenon of melting. The reason why the melt treatment time is set to within 30 seconds is because : If the processing time exceeds 30 seconds, the Mg2Si crystallized during casting or cooling after the homogenization process will be fully solid-dissolved in the base structure, not only manganese and silicon will tend to be saturated, but the metal strip will be rolled. The feeding speed will also become too slow, and as a result, the processing time will be longer, which will increase the manufacturing cost. After melt processing, it will be cooled to room temperature at a cooling rate of 10 ° C / sec or more. Is one of its characteristics. The reason for setting the cooling rate of the melt-treated • 13- (10) (10) 200536946 to 10 ° c / sec or more is because if the cooling rate does not reach 10 ° c / sec, during the cooling process , Silicon will crystallize on the grain boundary, which will lead to the deterioration of edge processability. After performing the homogenization treatment on the thin blank sheet, cold rolling may be further performed, and after the melt treatment is performed, it is cooled to room temperature at a rate of 10 ° c / sec or more, and the metal strip coil is placed in the chamber. The temperature is then maintained in a continuous annealing furnace at a temperature of 260 to 300 ° C for 30 seconds, and then cooled to room temperature at a rate of 10 ° C / second. Such a melt treatment process and a recovery process are usually preferably performed in a continuous annealing furnace (CAL). The so-called continuous annealing furnace (CAL) is a device for continuously melting a metal strip coil, and is characterized by including an induction heating device for performing heat treatment, a water tank for water cooling, and Air-cooled air nozzles, etc. Through this restoration process, during the process of being left at room temperature after the melt treatment, the GP zone that is naturally aged and crystallized can be re-solidified. It can be applied after coating, baking and heating. Get full strength. In addition, in order to obtain sufficient strength after coating, baking and heating, after the process of being melt-treated and left at room temperature, the restoration is performed at a temperature of 2 60 to 3 00 ° C. deal with. If the temperature of the recovery process is lower than 26 ° C, sufficient baking hardenability cannot be obtained. However, if it exceeds 300 ° C, the edge processability will be deteriorated. As to why the retention time of the recovery process should be The reason for limiting it to less than 30 seconds is that if the processing time exceeds 30 seconds, 'not only in the process of being placed at room temperature after melt treatment', the natural aging can be performed -14- 200536946 (11) crystallization The GP zone that comes out is fully re-solidified, and the feeding speed of the metal strip coil becomes too slow. As a result, the processing time will be longer, and the manufacturing cost will be increased. After the homogenization treatment, cold rolling may be further performed, and then the continuous annealing furnace (CAL) is used for melt treatment, and then water-cooled to 2 5 at a cooling rate (first cooling rate) of 10 ° C / sec or more. Below 0 ° C, then use air to cool it to 60 ~ 100 at a cooling rate of 1 ~ 2 (TC / sec) (second cooling rate), then roll the thin blank into a metal strip, and then cool it. Until room temperature This melt treatment and subsequent cooling are usually carried out using a continuous annealing furnace (CAL). This melt treatment and subsequent cooling can be performed to uniformly generate supply in the base structure. Heat treatment (preliminary aging treatment) of the crystal nuclei that are "cooled out" to obtain sufficient strength after coating, baking, and heating. After homogenizing the thin green sheet, cold rolling can be performed and then implemented. After heating to 5 3 0 to 560 t at a speed of 10 ° c / second or more, and maintaining the state in a melt treatment within 30 seconds, cool to room temperature at a speed of 10 ° C / second or more, and then, After carrying out a recovery process within 260 to 300 ° (: within a range of 30 seconds, and then cooling to 60 to 100 ° C at a cooling rate of 1 ° C / second or more, the thin blank sheet is rolled into a metal strip roll. Preliminarily aging treatment to cool down to room temperature. This melt treatment, and subsequent cooling, recovery treatment, and subsequent cooling are usually carried out using a continuous annealing furnace (CAL). According to this manufacturing Method 'Melting Place it at room temperature after the treatment. 'No -15- (12) (12) 200536946 Only the G · P bands that have been crystallized by natural aging can be sufficiently re-solidified', and it can be cooled after the restoration treatment. The heat treatment (preliminary aging treatment) of the crystal nuclei for the precipitation of / 3, is uniformly generated in the altar structure, so that the endurance after coating and baking heating can be further improved. Next, the alloy of the present invention will be described. The meaning of the ingredients and the reasons for limiting its content. Magnesium, one of the necessary elements, will be solidified in the almond after the melt treatment, and will be crystallized together with silicon during coating and baking heating as Strengthening phase to increase strength. The reason why the amount of magnesium is limited to 0.30 to 1.00% by weight is because if the amount is less than 0.30% by weight, the effect is small, and if it exceeds 1.000% by weight, the melt treatment will be reduced. Back edge workability. A more preferable range of the magnesium content is limited to 0.30 to 0.70 wt%. Silicon, which is one of the essential elements, will be treated with magnesium as a mesophase of Mg2Si, which is called Θ, during coating and baking heating, or A strengthened phase similar to this mesophase is crystallized, thereby improving the strength. The reason for limiting the content of silicon to 0.30 to 1.20 wt% is because if it is less than 0.30 wt%, the effect is small, and if it exceeds 1.2, 〇wt%, will reduce the edge edge processability after melt processing. The better range of the content of silicon is limited to: 0.60 ~ 1.20wt%. Iron, one of the essential elements, is made by iron and silicon, If manganese is present at the same time, a large amount of aluminum-iron-silicon crystals and aluminum- (iron-manganese) -silicon crystals with a size of 5 μm or less can be generated during casting to increase the recrystallized core, thereby Refinement of the recrystallized grains can be achieved to obtain a plate with excellent moldability. -16- (13) (13) 200536946 material. If the iron content is less than 0.5% by weight, 'the effect is not significant' if it exceeds 〇.50wt%, coarse aluminum-iron-silicon crystals and aluminum- (iron-manganese) will be produced during casting _ Silicon crystals will not only reduce the edge processability, but also reduce the solid solution amount of silicon in the thin blank, thereby reducing the baking hardenability of the final sheet. Therefore, the iron content is between 0 · 0 A range of 5 to 0 · 50 wt% is preferable. A more preferable range of iron content is: 0 · 0 5 to 0.3 0 wt ° / °. Manganese, one of the necessary elements, is added to make the recrystallized grains more Refined element. By suppressing the size of the recrystallized particles to a small extent of 10 to 25, it can become a sheet with excellent moldability. If the content of manganese is less than 0.05 wt%, its effect is insufficient. If it exceeds 0.50wt%, coarse aluminum-iron-silicon precipitates and aluminum- (iron-manganese) -silicon precipitates will be produced during casting, which will not only reduce edge workability, but also reduce thin blanks. The solid-melting amount of silicon in the lead reduces the baking hardenability of the final sheet. Therefore, the content of manganese is preferably in the range of 0.05 to 0.5 wt%. A more preferable range of the content of manganese is : 0.05 to 0.3 Owt%. Titanium, one of the necessary elements, if the content is not more than 0.10wt%, even Titanium having such a degree does not hinder the effect of the present invention, and can act as a micronizer for crystal grains of a thin slab, which can reliably prevent casting defects such as cracks on the slab. If the content of titanium is When the content is less than 0.05% by weight, the effect is insufficient. If the content of titanium exceeds 0.1% by weight, coarse intermetallic compounds such as TiAl3 will be generated during casting, so the edge workability will be significantly reduced. Therefore, the content of titanium is preferably in a range of 0.00 5 to 0.10 wt%. A more preferable range of the content of titanium is: 0.005 to 0.05 wt%. Copper, which is not an absolutely necessary element, can promote aging hardening ', and further improve the hardening property of the tube baking -17- (14) (14) 200536946. If the content of copper is less than 0.05% by weight, the fit effect is small. If the content of copper exceeds 0.70% by weight, the endurance of the aluminum plate after preliminary aging treatment is increased. And the corrosion resistance is also significantly reduced. Therefore, the content of copper is preferably in the range of 0.05 to 0.7 wt%. A more preferable range of the copper content is: 0.10 to 0.60 wt%. Plutonium, which is not an absolutely necessary element, is added as an element that promotes miniaturization of recrystallized grains. If the content is less than 0. 0 5 wt%, the effect is not sufficient. If the content of pin exceeds 0.4 0 wt%, coarse tin-chromium precipitates will be produced during casting of the blank and the edges will be reduced. Processability. Therefore, the content of the pin is preferably in the range of 0.5 to 0.40 wt%. A more preferable range of the content is: 0.05 to 0.30 wt%. As described above, according to the present invention, an aluminum-magnesium-silicon-based alloy plate for an automobile body panel having excellent baking hardenability and edge workability after final annealing can be manufactured at low cost. Although it is necessary to carry out restoration treatment or high-temperature coiling to suppress natural aging hardening in the same manner as the conventional method, the process of removing the surface layer and hot rolling up to the previous stage can be greatly simplified, so it can be greatly reduced. Overall manufacturing costs. Examples are given to explain the best mode of the present invention. [Embodiment 1] In the following embodiments, the samples after the cold rolling process are not metal strip coils, but all are cutting plates. Therefore, in order to simulate the continuous annealing process of metal strip coils performed by a continuous annealing furnace (CAL), the sample is melted in a quenching furnace using a neutral salt and cold water quenched or -18- (15 ) (15) 200536946 8 Warm water quenching at 5 ° C. The molten metal having the composition shown in Table 1 was degassed and then statically casted into a green sheet having a thickness of 7 mm by a two-belt casting method. By observing the microstructure at a thickness of 1/4 of the slab, the DAS (Dendrite Arm Spacing) was measured by the intersection method to calculate the cooling rate of 75 ° C / sec. This blank was subjected to a predetermined homogenization treatment, and then cooled to room temperature at a predetermined cooling rate, and then cold-rolled to produce a sheet having a thickness of 1 mm. Next, for this cold-rolled sheet, melt treatment was performed in a quenching furnace using a neutral salt, and then (5) 8 5 t of warm water was used for quenching, and then immediately inserted into the annealing furnace at a predetermined ambient temperature Heat treatment is performed under predetermined conditions; or (2) After quenching with cold water, leaving it to stand at room temperature for twenty-four hours, heat treatment is performed under predetermined conditions. In addition, in order to simulate the car coating process, it was maintained at room temperature for one week after heat treatment, and its endurance was measured at 0.2%. In addition, the baking treatment was performed at 180 ° CX for 30 minutes. After the test, the endurance of 0.2% was also measured. 11¾ • The difference in endurance after fr has been subjected to baking treatment is regarded as "baking hardening property", and those exceeding 80 MPa are judged to have excellent baking hardening property. In addition, in order to simulate the edge processing, the plate before baking treatment is given a 5% pre-deformation, and then it is bent into a U shape with a jig of r = 0.5 mm, and then put into 1 mm. The thickness of the spacer is then adjusted to 80. Bend. The symbol of 0 is noted for those without cracks, and the symbol of χ is noted for those with cracks. The detailed board-making process and evaluation results are shown in Tables 2 to 6. 200536946 (16) Table 1 Synthetic composition (wt%) Alloy number Mg Si Fe Mn Cu Zr Ti A 0.5 0.7 0.2 0.2 _ _ 0.02 B 0.5 0.8 0.2 0.2 _ _ 0.02 C 0.6 0.8 0.2 0.2 _ _ 0.02 D 0.5 1 0.2 0.2 0.5-0.02 E 0.5 0.8 0.2 0.2-0.15 0.02 F 0.4 1.2 .2 0.2 0.2 0.1-0.02

Table 2 shows the results of changing the conditions of the homogenization treatment and the cooling rate after the homogenization treatment. The homogenized cold-rolled slab was cold-rolled to a thickness of 1 mm, and this cold-rolled slab was melt-treated at a predetermined temperature for 15 seconds using a neutral salt quenching furnace, and then subjected to 8 5 ° After being quenched with warm water, it was immediately inserted into an annealing furnace at an ambient temperature of 85 ° C for 8 hours of preliminary aging treatment. Those meeting the condition range of the present invention (1 to 7) all have excellent baking hardenability and edge workability. Without homogenization, baking hardenability and edge workability are not good (8, 10). In addition, if the cooling rate after the homogenization process is too slow, the baking hardenability is deteriorated (9). -20- (17) 200536946 Marginal workability 〇〇〇〇〇〇〇〇〇 丨 Bake I hardenability (MPa) (N or—H s 1 < ON ON O On 5: 00 before and after baking Endurance (MPa) 100/192 1 110/210 Delete 107/209 1 122/221 115/213 117/208 1 1 110/158 90/145 92/160 Preliminary aging 85 ° Cx8h 85 ° Cx8h 85 ° C > < 8h 85 ° C > < 8h 85 ° Cx8h 85 ° C > < 8h 85 ° Cx8h 85 ° C × 8h 85 ° C > < 8h 85 ° C > < 8h I Melt treatment temperature 550 ° C 550 ° C 530 ° C 540 ° C 550 ° C 550 ° C 550 ° C 550 ° C 550 ° C Cold rolled platei Thickness 1mm 1mm 1mm 1mm 1 1mm 1mm 1mm 1mm 1mm linm rrn 1 Persuade m μ Cooling speed (° C / h) 1500 1700 〇 ^ T) 1000 1000 1000 1000 Destruction 250 Destruction retention time VO 〇o 〇〇〇δ Holding temperature § § 550 i 丨 530 530 om ^ T) 550 560 Heating rate (° C / h) o O j Casting method / Blank thickness (mm) Dual band / 7 Dual band / 7 Dual band / 7 Dual band / 7 1 Dual band / 7 Dual band / 7 Dual band / 7 Dual band / 7 Dual band / 7 Double-belt / 7 Alloy number < PQ PQ UQ ω < PQ PQ q Η-ί (N m inch in 〇〇 ON o invention comparison

-21-(18) 200536946 Table 3 shows the results when the temperature / time of the homogenization process was changed. The homogenized cold-rolled blank was cold-rolled to a thickness of 1 mm. This cold-rolled blank was quenched with a neutral salt, and melt-treated at a predetermined temperature for 15 seconds, and then subjected to 8 5 ° c After the warm water quenching treatment, it was immediately inserted into an annealing furnace at an ambient temperature of 85 ° C for 8 hours of preliminary aging treatment. Those meeting the condition range of the present invention (1 1 to 4) all have excellent baking hardenability and edge workability. If the temperature of the homogenization process is too low (1 5) or the holding time is too short (〗 6), the baking hardenability and edge workability will deteriorate.

-22- 200536946 I edge i ... workability 〇〇〇〇XX baking hardening (MPa) o T—H ssr—H sr 1 i ο JO endurance before and after baking YS (MPa) 110/210 111 / 213 i- 1 107/209 i- 112/215!-95/165 100/175 Preliminary aging 85 ° C > < 8h 85 ° C > < 8h 85 ° Cx8h 85 ° 〇8h 85 ° 8h 85 ° C > < 8h Melt treatment temperature O in 530 540 550 ^ T) Thickness of cold car L plate 1mm 1mm 1mm 1mm 1mm 1mm mi 1 Cooling speed (° C / h) 1500 1500 1500 1500 1500 1500 Holding time IT ) O 1-Ή η Holding temperature § IT) 560 550 om un 500 560 Heating rate (° C / h) Casting method / Blank thickness I | (mm) Double-belt type / 7 Double-belt type / 7 Double-belt type / 7 double-belt type / 7 double-belt type / 7 double-belt type / 7 I alloy ί i number I PQ m υ U PQ CQ Q h— (：: (N inchΌ invention comparison

200536946 (20) Table 4 shows the results after changing the homogenization treatment conditions and the restoration treatment conditions. The homogenized cold-rolled blank was rolled to a thickness of 1 mm. This cold-rolled blank was melt-treated at a predetermined temperature for 15 seconds in a neutral salt quenching furnace, and then subjected to cold-water quenching. After that, it was left at room temperature for 24 hours, and then kept at a predetermined temperature for 5 seconds to perform a recovery process. Those meeting the conditions (17 to 20) of the present invention have excellent baking hardenability and edge workability. If the recovery processing temperature (reheating temperature) is too low (2 1), the baking hardenability will deteriorate. If the restoration temperature (reheating temperature) is too high (22), the edge workability will deteriorate. In addition, even if the restoration processing conditions are within the scope of the present invention, the edge workability is deteriorated in the case where the homogenization treatment temperature is too low (2 3) or the holding time is too short (2 4). If the cooling rate after homogenization is too slow (25), the baking hardenability will be deteriorated.

-24- 200536946

iH, Haii `` # · $ Λ5 > Number of sMlfsl more mouth ΐΜ / ^ 4ς_ίΜ ^ Μ & Inch edge edge i... Workability 〇〇〇〇〇XXX 〇 Baking hardening! (MPa) oris 1— ^ s rH s S ov ^ o Before and after baking: Endurance YS (MPa) 110/210 111/213 107/209 112/215 95/170 127/229 97/197 90/160 95/145 Reheat temperature 270 O ( N 290 290 240 310 290 280 290 Melt temperature / s P 〇m un 540 550 in 550 550 Cold milk plate thickness 1mm 1mm 1 1mm 1mm 1mm ί 1mm 1 1mm 1mm 1mm rm 1 Sri m Cooling speed 1 ί (° c / h) 1500 2000 1000 2500 1500 1500 〇1000 200 1 Holding time o VO δ 1 Holding temperature / ^ \ § 550 530 560 560 500 560 Heating rate (° C / h) Casting method / I blank thickness (mm ) Double-Band / 7 Double-Band / 7 Double-Band / 7 Double-Band / 7 I Double-Band / 7! Double-Band / 7 Double-Band / 7 1 Double-Band / 7 ί Double-Band / 7 Alloy number PQ 0Q UU m PP PQ PQ PQ q 1—Η Bu 00 (N CN rn (N (N invention 1 comparison-25- 200536946 (22) Table 5 shows the changes in homogenization treatment conditions and melt treatment The result of the situation after the cooling method. The cooling rate after the melt treatment is divided into two stages, and the cooling rate from the melt treatment temperature to the intermediate temperature is defined as the first cooling rate, from the intermediate temperature to the winding The cooling rate up to the temperature of the metal strip is defined as the second cooling rate. The slab after the homogenization process is cold-rolled to a thickness of 1 mm, and this cold-rolled sheet is subjected to a neutral salt quenching furnace at a predetermined temperature. After the melt treatment for 15 seconds, it is cooled to the intermediate temperature at the first cooling rate, and then cooled to the temperature of the wound metal strip at the second cooling rate, and then cooled at a rate of 5 ° C / hour. Up to room temperature. Those who meet the conditions of the present invention (2 6 to 2 8) have excellent baking hardenability and edge processability. If the first cooling rate after melt processing is too slow (29) If the second cooling rate is too slow (3 1); or if the intermediate temperature is too high (3 0), the edge processability will be deteriorated. If the temperature when winding the metal strip is too low (3 2), the baking hardenability will be deteriorated. Conversely, if the temperature when winding the metal strip is too high (3 3), the edge processability will deteriorate. In addition, when the homogenization treatment temperature is too low (3 4) or when the holding time is too short (3 5), the edge processability is deteriorated. If the cooling rate after homogenization is too slow (3 6), the baking hardenability will deteriorate. -26- (23) 200536946 (23)

ώΗαίίΙί # · $ Λ5 > Awake line EMsis plate _ sun collar ii · 坭 柁 一 ί®Λ3 > Μ% ί s edge edge processability 1_ 〇〇〇XXX 〇XXX 〇 baking hardening (MPa) O s 〇 ON ON cn oo § Endurance before and after baking YS (MPa) 1_ 110/210 105/207 101/211 106/201 101/197 102/198 112/165 130/240 97/197 -J 104/194 89/134 Temperature when winding the metal strip (° C) 00 ο § § go 00 m 00 o 〇〇 2nd cooling rate rc / s) Intermediate temperature 丨 oc) i 1_ 200 200 200 200 300 250 200 200 200 200 200 1 Cooling speed cam O ο r— 'o 〇r— ^ ot—1 ο oooo Melt treatment temperature rc) 550 om κη 〇wo 550 550 〇un uo yr) Cold rolled plate 1 thickness_ 1mm 1 mm lmm lmm lmm lmm lmm lmm lmm lmm \ lmm lmm mi 1 eti m Μ Cooling speed (° C / h) 1500 Nooo 1000 Ί 1500 1500 1500 1500 2000 1000 1000 200 Hold time IT) VO ^ sO VsO — δ Hold i temperature P! 500 560 550 o § 560 560 560 o ID sm 560 Heating rate I (° C / h) Casting method / Blank thickness (mm) Double belt type / 7 Double belt type / 7 Belt / 7 Double-Band / 7 Double-Band / 7 Double-Band / 7 Double-Band / 7 Double-Band / 7 Double-Band / 7 Double-Band / 7 Double-Band / 7 Number DQ PQ CO 0Q CQ CQ DQ CQ CQ cn Q (N (N 00 (N ON (N 04 m cn m Invention 1! | Comparison -27- (24) (24) 200536946 Table 6 shows the recovery temperature after the melt treatment has been changed ( Reheating temperature) and the temperature at the time of winding the metal strip. The slab after homogenization was cold-rolled to a thickness of 1 mm. This cold-rolled sheet was subjected to a neutral salt quenching furnace at a predetermined temperature. After the melt treatment with the temperature maintained for 15 seconds, it was quenched with cold water, left at room temperature for 24 hours, and then maintained at a predetermined temperature (reheating temperature) for 15 seconds, and then at 10 t / sec. The cooling rate was cooled to the temperature of the coiled metal strip, and then cooled to room temperature at a cooling rate of 10 ° C / hour. Those meeting the condition range of the present invention (37 to 40) have excellent baking hardenability and edge workability. If the recovery temperature (reheating temperature) is too high (41), the edge workability will deteriorate. If the recovery temperature (reheating temperature) is too low (42), the baking hardenability will decrease. If the temperature at the time of winding the metal strip is too low, (4 3) 'bake hardenability will deteriorate. Conversely, if the temperature at which the metal strip is wound is too high (4 4), the edge workability deteriorates.

-28- 200536946

-iilssll— -si edge edge workability 〇〇〇〇 × 〇〇X baking hardening (MPa) 〇Γ1 'ir-Η inch T-Η T-H t-H (N 1- ^ ot-H r- H JO OO rH i1 mi Endurance before and after baking i YS (MPa) 121/231 125/237 117/228 119/231 124/234 111/198 110/185 131/249 Temperature when winding metal strip (° C ) o 00 § o rH Reheating temperature (° c) 270 270 290 290 290 320 250 250 260 290 Melt temperature (° c) 550 530 O in 550 550 550 Alloy number ί PQ CQ PQ CQ P3 PQ PQ PQ 1 ID Pi 00 On cn o Qin < 9 rn Invention -1 Comparison ^-00000- 5X 000 ^ -29- (26) (26) 200536946 [Industrial availability] According to the method provided by the present invention, it can be compared with Conventional technology produces a sheet of aluminum-magnesium-silicon alloy that can be used for forming parts such as flexure forming and press forming of automobile parts and home appliances at a lower cost.

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Claims (1)

200536946 (1) X. Application for patent scope 1 · A method for manufacturing an Al-Mg-Si alloy plate with excellent baking hardenability and edge workability, which is characterized in that it will contain magnesium ·· 0.3 0 ~ 1 · 0 0 wt%, 5 y ·· 0 · 3 0 ~ 1 · 2 0 wt%, iron: 0.05 to 0.50 wt%, fierce: 0.05 to 0.50 wt ° / 〇, and i too: 0.005 to 0.1 wt%, or It also contains one of copper: 0.05 to 0.70 wt% or zirconium: 0.50 to 0.40 wt%, and the remainder is a molten alloy composed of aluminum and unavoidable impurities. The cooling rate at the thickness of 1/4 of the plate is 40 ~ 150 ° C / sec. The blank plate with a thickness of 5 ~ 15 mm is casted, and then rolled into an aluminum alloy strip, and then homogenized. , At a cooling rate of more than 500 ° C / hour, at least to less than 25 0 ° C, then cold rolling, and then melt heat treatment. 2 · The method of manufacturing an Al-Mg-Si alloy plate with excellent baking hardenability and edge workability as described in item 1 of the scope of patent application, wherein the above-mentioned homogenization treatment is performed by using a graded annealing furnace in 3 A temperature increase rate of 0 ° C / hour or more, the temperature is raised to 5 2 0 to 5 8 0 ° C, and the temperature is maintained at the temperature for 2 to 24 hours. 3. If a method for manufacturing an Al-Mg-Si alloy plate with excellent baking hardenability and edge workability is applied in item 1 or 2 of the scope of patent application, wherein the above-mentioned melt heat treatment is performed using a continuous annealing furnace, Take 10. (: The heating rate is higher than 5/0 to 5 3 0 ~ 5 60 ° C, and the temperature is maintained within 30 seconds at this temperature. 4 · As shown in item 3 of the patent application, it has excellent baking hardenability and A method for manufacturing edge-processable Al-Mg_Si alloy plate, after the melt heat treatment described in 200536946 (2) above, cooling to room temperature at a rate of 10 ° c / sec or more, and then continuously using The furnace is subjected to a recovery process that is maintained at a temperature of 260 to 300 ° C for less than 30 seconds, and cooled to room temperature at a cooling rate of 10 ° C / second or more. 5. If the scope of patent application is the third According to the method for producing an Al-Mg-Si alloy plate having excellent baking hardenability and edge workability, after the above-mentioned melt heat treatment, water cooling is performed at a cooling rate of 10 ° C / sec or more. Below 25 0 ° C, then use air to cool to 60 to 100 ° C at a cooling rate of 1 to 20 ° C / second, then roll it up and apply preliminary aging treatment to cool to room temperature. 6 · 如Excellent baking hardening and edge workability in the scope of patent application No. 3 A method for manufacturing an Al_Mg-Si alloy plate, wherein after the above-mentioned melt heat treatment, cooling to room temperature at a rate of 10 ° C / sec or more, and then using a continuous annealing furnace at a temperature of 2 0 to 30 The recovery process is maintained within 30 seconds at a temperature of 0 ° C, and it is cooled to 60 to 10 (TC) at a cooling rate of It / sec or more, and then rolled up, and then pre-aging treatment is performed until it is cooled to room temperature. -32- 200536946 Seven Wuming Saying Lists without Jane iLIu: No. is the symbol map of the Yuan Dynasty: the table design represents the current generation of one or two fingers. If there is no case for tense learning: