Abstract: An aluminum alloy sheet for motor vehicles is produced by casting a melt, containing 3.0-3.5 mass % Mg, 0.05-0.3 mass % Fe, 0.05-0.15 mass % Si, and less than 0.1 mass % Mn, a balance substantially being inevitable impurities and Al, into a slab having a thickness of 5 to 15 mm in a twin-belt caster so that cooling rate at ¼ depth of thickness of the slab is 20 to 200° C./sec; winding the cast thin slab into a coiled thin slab subjected to cold rolling with a roll having a surface roughness of 0.2 to 0.7 ?m Ra at a cold rolling reduction of 50 to 98%; subjecting the cold rolled sheet to final annealing either continuously in a CAL at a holding temperature of 400 to 520° C. within 5 minutes or in a batch annealing furnace at a holding temperature of 300 to 400° C. for 1 to 8 hours; and subjecting the resulting sheet to straightening with a leveler.

Abstract: An aluminum alloy sheet for motor vehicles is produced by casting a melt, containing 3.0-3.5 mass % Mg, 0.05-0.3 mass % Fe, 0.05-0.15 mass % Si, and less than 0.1 mass % Mn, a balance substantially being inevitable impurities and Al, into a slab having a thickness of 5 to 15 mm in a twin-belt caster so that cooling rate at ¼ depth of thickness of the slab is 20 to 200° C./sec; winding the cast thin slab into a coiled thin slab subjected to cold rolling with a roll having a surface roughness of 0.2 to 0.7 ?m Ra at a cold rolling reduction of 50 to 98%; subjecting the cold rolled sheet to final annealing either continuously in a CAL at a holding temperature of 400 to 520° C. within 5 minutes or in a batch annealing furnace at a holding temperature of 300 to 400° C. for 1 to 8 hours; and subjecting the resulting sheet to straightening with a leveler.

Abstract: An aluminum alloy sheet is manufactured by preparing a slab having a thickness of 5 to 15 mm with a continuous casting machine by a continuous casting process using molten alloy containing 0.40% to 0.65% of Mg, 0.50% to 0.75% of Si, 0.05% to 0.20% of Cr, and 0.10% to 0.40% of Fe, a remainder being Al; winding the slab into a coil; cold-rolling the slab into a sheet; subjecting the sheet to solution heat treatment in such a manner that the sheet is heated to a temperature of 530° C. to 560° C. at a heating rate of 10° C./sec or more and then maintained at the temperature for five seconds or more; quenching the sheet with water; coiling up the sheet; maintaining the sheet at a temperature of 60° C. to 110° C. for 3 to 12 hours; and then cooling the sheet to room temperature.

Abstract: An aluminum alloy sheet having excellent press formability and stress corrosion cracking resistance, comprises 3.3 to 3.6 percent by weight of Mg and 0.1 to 0.2 percent by weight of Mn, furthermore, 0.05 to 0.3 percent by weight of Fe and 0.05 to 0.15 percent by weight of Si, and the remainder comprises Al and incidental impurities, wherein the sizes of intermetallic compounds is 5 ?m or less, the recrystallized grain size is 15 ?m or less in the region at a depth of 10 to 30 ?m below the sheet surface, and the surface roughness is Ra 0.2 to 0.7 ?m.

Abstract: An aluminum alloy sheet is manufactured by preparing a slab having a thickness of 5 to 15 mm with a continuous casting machine by a continuous casting process using molten alloy containing 0.40% to 0.65% of Mg, 0.50% to 0.75% of Si, 0.05% to 0.20% of Cr, and 0.10% to 0.40% of Fe, a remainder being Al; winding the slab into a coil; cold-rolling the slab into a sheet; subjecting the sheet to solution heat treatment in such a manner that the sheet is heated to a temperature of 530° C. to 560° C. at a heating rate of 10° C./sec or more and then maintained at the temperature for five seconds or more; quenching the sheet with water; coiling up the sheet; maintaining the sheet at a temperature of 60° C. to 110° C. for 3 to 12 hours; and then cooling the sheet to room temperature.

Abstract: An aluminum alloy sheet for motor vehicles is produced by casting a melt, containing 3.0-3.5 mass % Mg, 0.05-0.3 mass % Fe, 0.05-0.15 mass % Si, and less than 0.1 mass % Mn, a balance substantially being inevitable impurities and Al, into a slab having a thickness of 5 to 15 mm in a twin-belt caster so that cooling rate at ¼ depth of thickness of the slab is 20 to 200° C./sec; winding the cast thin slab into a coiled thin slab subjected to cold rolling with a roll having a surface roughness of 0.2 to 0.7 ?m Ra at a cold rolling reduction of 50 to 98%; subjecting the cold rolled sheet to final annealing either continuously in a CAL at a holding temperature of 400 to 520° C. or in a batch annealing furnace at a holding temperature of 300 to 400° C.; and subjecting the resulting sheet to straightening with a leveler.

Abstract: An aluminum alloy sheet is manufactured by preparing a slab having a thickness of 5 to 15 mm with a continuous casting machine by a continuous casting process using molten alloy containing following components: 0.40% to 0.65% of Mg, 0.50% to 0.75% of Si, 0.05% to 0.20% of Cr, and 0.10% to 0.40% of Fe, remainder being Al, the components being essential elements, and optionally up to 0.15% Cu, 0.10% Ti; winding the slab into a coil; hot-rolling or directly coiling up the slab; cold-rolling the slab into a sheet; subjecting the sheet to solution heat treatment with a continuous annealing furnace; and then pre-aging the sheet. The aluminum alloy sheet has the same composition as the molten alloy, has a grain size of 10 to 25 ?m, is superior in bake hardenability, bendability, and surface quality (orange peel), and can be manufactured with low cost.

Abstract: An aluminum alloy sheet having excellent press formability and stress corrosion cracking resistance, comprises 3.3 to 3.6 percent by weight of Mg and 0.1 to 0.2 percent by weight of Mn, furthermore, 0.05 to 0.3 percent by weight of Fe and 0.05 to 0.15 percent by weight of Si, and the remainder comprises Al and incidental impurities, wherein the sizes of intermetallic compounds is 5 ?m or less, the recrystallized grain size is 15 ?m or less in the region at a depth of 10 to 30 ?m below the sheet surface, and the surface roughness is Ra 0.2 to 0.7 ?m.

Abstract: An aluminum alloy plate to be subjected to a bake coating contains silicon (Si) and magnesium (Mg) with the balance being aluminum (Al) and inevitable impurities. In order to set the content of Mg2Si in a range of 0.50% by weight?Mg2Si?1.00% by weight, when the Si content by weight percent is taken on an x-axis of rectangular coordinates and the Mg content by weight percent is taken on a y-axis of the rectangular coordinates, the Si and Mg contents are set in a region in a diagram formed by sequentially connecting a point A (0.18, 0.31), a point B (1.3, 0.31), a point C (1.3, 0.64), a point D (0.37, 0.64), a point E (0.37, 1.0), a point F (0.18, 1.0) and the point A (0.18, 0.31). Thus, a bake-hard effect can be obtained, and the aluminum alloy plate can be produced at a relatively low manufacturing cost.

Abstract: An aluminum alloy sheet for high-speed high-temperature blow forming has an aluminum alloy containing 4 to 5% of Mg, 0.35 to 0.5% of Mn and 0.001 to 0.05% of Cr, 0.6% or less of Si+Fe, 0.15% or less of Cu, and the balance being substantially Al. The aluminum alloy sheet has an elongation of 150% or more in a high-temperature tensile test at 400 to 550° C. and at a strain rate of 10?2/second or more, has a cavitation area percentage of 2% or less at the time of 100% tensile deformation, and is free from any abnormally grown grains of 100 microns or more. A formed piece of the aluminum alloy sheet also has a cavitation area percentage of 2% or less when blow-formed at 400 to 550° C. and at a reduction in sheet thickness of 65% or less, and is free from any abnormally grown grains of 100 microns or more.

Abstract: An aluminum alloy plate to be subjected to a bake coating contains silicon (Si) and magnesium (Mg) with the balance being aluminum (Al) and inevitable impurities. In order to set the content of Mg2Si in a range of 0.50% by weight≦Mg2Si≦1.00% by weight, when the Si content by weight percent is taken on an x-axis of rectangular coordinates and the Mg content by weight percent is taken on a y-axis of the rectangular coordinates, the Si and Mg contents are set in a region in a diagram formed by sequentially connecting a point A (0.18, 0.31), a point B (1.3, 0.31), a point C (1.3, 0.64), a point D (0.37, 0.64), a point E (0.37, 1.0), a point F (0.18, 1.0) and the point A (0.18, 0.31). Thus, a bake-hard effect can be obtained, and the aluminum alloy plate can be produced at a relatively low manufacturing cost.

Abstract: In the production of an aluminum alloy plate for an automobile body, a molten alloy having an aluminum alloy composition of 3.00% by weight≦Mg≦3.50% by weight, 0.20% by weight≦Fe≦0.60% by weight, 0.10% by weight≦Si≦0.15% by weight, 0.01% by weight≦Ti≦0.05% by weight, Mn≦0.05% by weight and the balance of aluminum containing inevitable impurities is subjected to a liquid metal rolling to provide a plate material; the plate material is subjected to a cold rolling to provide a cold-rolled plate; and the cold-rolled plate is subjected to an annealing treatment at a temperature T set in a range of 340° C.≦T≦400° C. and for a period of time t set in a range of 9 hours≦t≦11 hours.

Abstract: An aluminum alloy sheet for automotive use is provided which comprises a starting aluminum alloy sheet which has an alloy composition containing from 2 to 6% by weight of Mg, 0.15 to 1.0% by weight of Fe and from 0.03 to 2.0% by weight Mn, and a surface layer disposed over one surface of the starting alloy sheet to be pressed against electrodes for use in welding, the surface layer containing a particulate intermetallic compound has a particle diameter of 0.5 &mgr;m or more and a density of 4,000 pieces of particles per one mm2 or more. The product alloy sheet ensure least deformation of an electrode and stable weldability by means of continuous resistance spot welding.

Abstract: A continuously cast and rolled sheet of an aluminum alloy having Mg in a content of 3 to 6% by weight is annealed, followed by strain correction, heat and hold treatment at a given temperature between 240° C. and 340° C. for one hour or more, and slowly cooling treatment, to thereby provide an aluminum alloy sheet having enhanced resistance to stress corrosion cracking and improved shape fixability. The slowly cooling treatment is carried out at a cooling rate chosen from a preset cooling zone corresponding to a present temperature zone S defined in obliquely lined surround form in the accompanying drawing.

Abstract: The invention provides an aluminum alloy sheet that has excellent formability, high coat-baking hardenability, excellent corrosion resistance, and is particularly suitable for external automobile body plates. The aluminum alloy sheet comprises: 0.9 to 1.3 wt. % of Si, 0.4 to 0.6 wt. % of Mg, 0.05 to 0.15 wt. % of Mn, 0.01 to 0.1 wt. % of Ti, with the remainder comprising Al and inevitable impurities, while limiting Fe as an impurity to 0.2 wt. % or less and Cu as an impurity to 0.1 wt. % or less. The aluminum homogenizing an aluminum ingot with the above-described composition; cooling the homogenized ingot to a temperature of 450.degree. C. or below to begin hot-rolling; finishing hot-rolling in a temperature range from 250 to 350.degree. C.; applying intermediate annealing to the hot-rolled plate; conducting cold-rolling at a draft of 70% or more; applying a solid solution treatment followed by quenching the alloy sheet and holding it at 530.degree. C. or above for 60 sec.

Abstract: The invention provides an aluminum alloy sheet that has excellent formability, high coat-baking hardenability, and ensures a proof stress of 200 MPa or more after the coat-baking stage, and that gives favorable product surface quality after the forming stage and excellent corrosion resistance, and that is particularly suitable for external automobile body plates. The aluminum alloy sheet comprises: 0.9 to 1.3 wt. % of Si, 0.4 to 0.6 wt. % of Mg, 0.05 to 0.15 wt. % of Mn, 0.01 to 0.1 wt. % of Ti, with the remainder comprising Al and inevitable impurities, while limiting Fe as an impurity to 0.2 wt. % or less and Cu as an impurity to 0.1 wt. % or less; a coating film of a lubricant composition containing a water-dispersible polyurethane resin and a natural wax on the aluminum alloy sheet.

Abstract: A method of bending extruded shapes of the present invention controls a bending radius and a bending angle in accordance with a moving distance of a movable bending die. In the bending process, hardness of an extruded shape to be processed is measured and converted into proof stress, and the bending condition for compensating the springback is determined. A correction coefficient C showing a ratio of a practical value of the moving distance and a theoretical value of the moving distance in a case of no spring-back occurring is defined by a function of Young's modulus E, geometrical coefficient Z, bending radius R and proof stress .sigma..sub.0.2 for the extruded shape to be processed.