JP5107039B2 - Aluminum automotive structural members - Google Patents

Abstract

Disclosed is a method for producing aluminum vehicular structural parts or members such as from molten aluminum alloy using a continuous caster to cast the alloy into a slab. The method comprises providing a molten aluminum alloy consisting essentially of 2.7 to 3.6 wt. % Mg, 0.1 to 0.4 wt. % Mn, 0.02 to 0.2 wt. % Si, 0.05 to 0.30 wt. % Fe, 0.1 wt. % max. Cu, 0.25 wt. % max. Cr, 0.2 wt. % max. Zn, 0.15 wt. % max. Ti, the remainder aluminum, incidental elements and impurities and providing a continuous caster such as a belt caster, block caster or roll caster for continuously casting the molten aluminum alloy. The molten aluminum alloy is cast into a slab which is rolled into a sheet product and then annealed. The sheet has an improved distribution of intermetallic particles (Al-Fe, Al-Fe-Mn or Mg<SUB>2</SUB>Si) and improved formability. Thereafter, the sheet product is formed into the vehicular structural part or member with sufficient strength and formability required by automotive industry.

Description

  The present invention relates to an aluminum alloy vehicle structural component or member, and more specifically, casts an aluminum alloy into a sheet having good molding characteristics, and the sheet is a dash panel, floor panel, door panel, window decoration, radio bracket, The present invention relates to a method for forming a structural component or member for a vehicle such as a reinforcing material for a panel.

  In many cases, continuous casting can result in substantial energy savings and overall processing cost savings compared to DC casting methods, so it can be melted using twin belts, twin rolls, or block casters. Continuous casting of aluminum into slums is preferred over DC casting. In a continuous casting process, molten metal is continuously introduced into an advancing mold and a slab is produced that can be collected or continuously formed into a sheet product that is wound into a coil. However, continuous casting is not without problems. For example, the alloy composition and processing steps must be carefully controlled in order to have formability to avoid cracking during forming and to have the required strength characteristics in the final product. That is, the alloy and its processing must be carefully controlled in order to provide a sheet with formability suitable for the processing steps necessary to form the final product or its structural components. If the alloy and processing steps are not controlled, cracks can occur in the forming step and the formed parts must be discarded. Thus, the choice of aluminum alloy, its continuous casting method, and holding fasteners during the manufacture of vehicle structural parts or parts, while at the same time bending, stamping, deep drawing, in order to avoid problems of crushing or cracking, for example. There is a great need for thermomechanical processing methods that provide sheet products having forming and strength properties that allow forming operations such as stretching, crimping, or crimping.

  Various patents disclose continuous casting of molten aluminum and rolling slabs produced therefrom into sheet products. For example, US Pat. No. 5,976,279 discloses a process for continuously casting an aluminum alloy and an improved aluminum alloy composition. The process includes the step of continuously annealing the cold-rolled strip using intermediate heating in intermediate annealing and / or the continuous annealing of the hot-rolled strip in an induction furnace. Including steps. The alloy composition has mechanical properties that can be selectively varied by changing the stabilization annealing time and temperature.

  U.S. Pat. No. 6,264,765 discloses a method and apparatus for casting, hot rolling and annealing non-heat treated aluminum alloys. The method and apparatus include continuous casting, hot rolling, and in-line induction heating of an aluminum sheet to obtain mechanical properties within the specification tolerances of the hot rolled product.

  US Pat. No. 5,985,058 discloses a process for continuously casting aluminum alloys and an improved aluminum alloy composition. The process includes heating the cast strip to a temperature above the extrusion temperature of the cast strip from the chill block, before, during, or after hot rolling. The alloy composition has a relatively low magnesium content but possesses excellent strength properties.

  U.S. Pat. No. 5,993,573 discloses a process for continuously casting an aluminum alloy and an improved aluminum alloy composition. The process includes (a) heating before, during, or after hot rolling to a temperature above the extrusion temperature of the cast strip from the chill block; and (b) the cold rolled strip produced from the cast strip. Stabilizing or post-annealing in an induction furnace.

U.S. Pat. No. 5,833,775 discloses an aluminum alloy sheet and a method for producing the aluminum alloy sheet. Aluminum alloy sheets are useful for forming stretched or iron-clad container bodies. The sheet preferably has an afterbake yield strength of at least about 255 MPa ( 37 ksi ) and an elongation of at least about 2 percent. Preferably, the sheet also has less than about 2 percent ears.

  U.S. Patent No. 6,086,690 discloses a process for producing high yield strength and ductile aluminum alloy articles that are particularly suitable for producing automotive panels. The process includes the steps of casting a non-heat treated aluminum alloy to form a cast slab and producing a final gauge sheet article, preferably afterwards, to anneal to cause recrystallization. Exposing to a series of rolling stages. The rolling step includes hot or warm rolling the slab to form an intermediate gauge intermediate sheet article, cooling the intermediate sheet article, and cooling the intermediate sheet article to form the sheet article. Warm or cold rolling the sheet to a final gauge at a temperature in the range of ambient temperature up to 340 ° C. The series of rolling steps is performed continuously without intermediate coiling or complete annealing of the intermediate sheet article. The invention also relates to an alloy sheet produced by the process.

U.S. Pat. No. 5,244,516 discloses an aluminum alloy plate for discs that is excellent in Ni-P plating and adhesion of the plating layer and has high surface smoothness with minimal hump products and micropits. The aluminum alloy plating has, as essential components, Mg in an amount of more than 3% and not more than 6%, Cu in an amount of not less than 0.03% and less than 0.3%, and 0.03% In the case of semi-continuous casting, it contains 0.07% or less of Fe and 0.06% or less of Si as impurities. In the case of strip casting, it contains less than 0.1% Fe and less than 0.1% Si, with a maximum size of less than 10 μm and less than 5 per 0.2 mm ^2. Al with a particle number greater than 5 μm Comprising a Fe phase intermetallic compound and Mg-Si phase intermetallic compound with large number of particles than 5μm is less than 5 the maximum size and 0.2 mm ² per below 8 [mu] m.

  U.S. Pat.No. 5,514,228 includes the steps of hot rolling an aluminum alloy sheet stock and annealing and consolidating it without substantial intercooling and rapid quenching. A method for producing aluminum sheet stock is disclosed.

  Despite these disclosures, the choice of aluminum alloys and continuous casters, optimized thermal machines to provide good strength and formability levels that allow ease of forming into complex parts without cracks There is a great need for a method of manufacturing vehicle parts or components using mechanical processing.

  The term “formability” as used herein is used to describe the ease with which a sheet of metal can be formed through plastic deformation.

  The term “aluminum”, as used herein, is intended to include aluminum and its alloys.

  The term “automotive” as used herein may include automotive and other vehicle parts or members as described herein, as well as other transport parts or members having a similar structure. Is intended.

  It is an object of the present invention to provide an improved low cost process that includes continuous casting and rolling to continuously produce aluminum sheet products having a certain level of formability.

  It is another object of the present invention to provide a process that includes continuously casting a slab and rolling the slab suitable for use in vehicle component manufacturing into a sheet product.

  Process of continuously casting molten aluminum into a slab and rolling the slab into a sheet product to satisfy forming requirements such as bending, stamping, stretching and deep drawing of vehicle structural parts or components It is still another object of the present invention.

  Of a threaded fastener that is attached to a slab by using a continuous casting machine, continuously rolling the slab to produce a sheet product, and crimping the sheet product around the fastener It is yet another object of the present invention to provide an improved process for producing an aluminum sheet product by annealing the sheet product to form a vehicle structural part or panel member having such fasteners. Is the purpose.

  Formed to continuously cast aluminum alloy into slab, roll slab into sheet product, anneal sheet product with good level of formability, eg mechanically fasten to support member Manufacturing a vehicle member, such as a shallow or deep molded panel member, comprising forming a sheet product into a panel having a threaded fastener attached thereto by crimping to provide the vehicle member. It is yet another object of the present invention to provide a process for achieving this.

  2.7 to 3.6 wt% Mg, 0.1 to 0.4 wt% Mn, 0.02 to 0.2 wt% Si, 0.05 to 0.30 wt% Fe, up to 0 .1% by weight Cu, up to 0.25% by weight Cr, up to 0.2% by weight Zn, and up to 0.15% by weight Ti with the balance being aluminum, indeterminates and impurities For casting an alloy into a slab that is hot-rolled and annealed to provide a sheet product suitable for molding into a vehicle structural part or frame member that requires good formability. It is yet another object of the present invention to provide a process.

In accordance with these objectives, a method is provided for manufacturing an aluminum vehicle structural part or member from a molten aluminum alloy using a continuous caster to cast the alloy into a slab. The method essentially consists of 2.7-3.6 wt% Mg, 0.1-0.4 wt% Mn, 0.02-0.2 wt% Si, 0.05-0. Contains 25 wt% Fe, up to 0.1 wt% Cu, up to 0.25 wt% Cr, up to 0.2 wt% Zn, and up to 0.15 wt% Ti with the balance being aluminum Providing a molten aluminum alloy consisting of unwanted components and impurities, and providing a continuous caster, such as a belt caster, for continuously casting the molten aluminum alloy. Molten aluminum alloy, Al-Fe, Al-Fe -Mn, or is cast into a slab having the intermetallic particles comprising the _Mg 2 Si. The slab is rolled into a sheet product and then the sheet product is annealed to provide a sheet product having a substantially uniform distribution of intermetallic particles or fewer striations for improved formability. It will be. Thereafter, the sheet product is formed into a vehicle structural component or member, such as a panel member for a door or hood having fasteners crimped thereon, for example.

  Alternatively, the hot rolled sheet can be cold rolled after hot rolling and then annealed before the forming step. In yet another embodiment, the hot rolled sheet can be annealed or homogenized and then cold rolled into a cold rolled sheet product. In order to provide a product suitable for various forming steps, the cold rolled product can be annealed.

  These and other objects will be apparent from reading the accompanying specification and claims.

For example, a vehicle structural component or member of the present invention is a controlled amount of magnesium, iron, silicon, and for the required strength and formability in sheet products produced by casting and thermomechanical processes. It consists of an aluminum-based alloy containing manganese. The total amount of alloy components is required to be controlled to meet strength requirements without causing casting difficulties in the process. In addition, the amount of alloy components, in particular, the amount of heat, manganese, and silicon, is also required to be controlled to meet the formability requirements. Al-Fe, Al-Fe- Mn, or, _Mg 2 Si intermetallic particles occurs during solidification. That is, after rolling a continuously cast slab, the distribution, size, and amount of such intermetallic particles can dramatically affect the formability of the sheet material.

Al-Fe, Al-Fe- Mn, or intermetallic particles containing _Mg 2 Si occurs during solidification. After rolling a continuous belt cast aluminum slab, the distribution of such intermetallic particles can be severely striped or lined, which can cause forming problems. In comparison, direct chill (DC) ingot casting materials have a more uniform distribution of intermetallic particles and provide good formability. The striations of the intermetallic grain structure cause stress concentrations during plastic deformation that degrades the formability of the sheet product. Thus, it is desirable for the rolled sheet of the present invention to have a substantially uniform distribution or fewer intermetallic grain lines to provide improved formability.

  Thus, the aluminum-based alloy is essentially 2.7-3.6 wt% Mg, 0.1-0.4 wt% Mn, 0.02-0.2 wt% Si, 0.05 ~ 0.30 wt% Fe, up to 0.15 wt% Cu, up to 0.25 wt% Cr, up to 0.25 wt% Zn, up to 0.15 wt% Ti with the balance being aluminum , Indefinite components and impurities. Preferably, magnesium is maintained in the range of 2.8-3.3 or 3.5% by weight and manganese is preferably maintained in the range of 0.25-0.35% by weight. Further preferably, the iron is maintained in the range of 0.05 or 0.10 to 0.25 wt%, typically 0.05 to 0.2 wt%, and the silicon is 0.05 to 0.2 wt%. It is maintained within the range of 0.15% by weight. The impurities are preferably each limited to a maximum of 0.05% by weight, and the total combination of impurities should not be greater than 0.15% by weight.

  Thus, the use of an alloy of the above composition in the process of the present invention to form an automotive member having the required characteristics is to avoid the formation of an intermetallic particle structure that is detrimental to the forming operation. Requires careful control of the alloy components inside. That is, the strength and procedure required to form a sheet product having the desired properties during the formation process, such as avoiding undesirable properties that lead to, for example, crushing or cracking, while forming into the final product in the process. Due to the steps, there is great difficulty in balancing all the components in the alloy.

  Not only is it important to have controlled amounts of alloy elements and impurities as described herein, but also slabs produced by continuous casting, sheets formed from slabs, automotive parts processed from sheets Also, it must be prepared according to specific method steps in order to produce a sheet having the desired properties and an automotive structural part or member therefrom. That is, the process must be controlled to produce a product having the near formability characteristics of the DC ingot processed material without the cost penalty of the DC ingot process.

  Thus, referring to FIG. 1, there is shown a schematic diagram of a belt casting machine 2 and a rolling mill for producing a sheet suitable for forming a vehicle structural part or member according to the present invention.

  In FIG. 1, molten aluminum 10 is provided in a furnace or reservoir 12. Molten aluminum from reservoir 12 is directed along line 14 to tundish 16, from which molten aluminum is created through nozzles 18 by revolving belts 20, 22 and side drum blocks (not shown). Metered into advance mold. The belts 20 and 22 are rotated using a roll 24. Molten metal, such as molten aluminum, is solidified to form a continuous slab 15 between belts 20 and 22 that are cooled using a cooling spray 26. Belt casting machine 2 is disclosed in U.S. Pat. Nos. 3,864,973, 3,921,697, 4,648,438, 4,940, which are hereby incorporated by reference as if specifically set forth. No. 076 and No. 4,972,900. An improved nozzle for a belt caster is described in US Pat. No. 5,452,827, incorporated herein by reference.

  Another casting apparatus that can be used in the present invention is a block caster where the blocks are connected to form a belt and are included herein as a belt caster. As described with respect to the belt caster 2, tundish and nozzles are provided to move the molten metal to the block belt of the block caster, where solidification occurs to provide a solidified slab 15 and the block Is cooled to help solidify the molten metal.

  Yet another apparatus that may be used to cast a continuous strip or slab 15 is a roll caster that includes two rolls that rotate to provide a continuously advancing mold. As in the belt caster, the tundish and nozzle are used to move the molten aluminum into a mold defined by two rolls. Again, the roll is usually cooled to help solidify the molten metal into the strip or slab. A different casting machine is described in US Pat. No. 5,452,827. The use of the term “continuous caster” is intended to include all casters.

The molten aluminum alloy of the present invention has a temperature range of about 660 ° C to 716 ° C ( 1220 ° F to 1320 ° F ) , typically 677 ° C to 696 ° C ( 1250 ° F to 1285 ° F ) . In the range of 399 ° C to 621 ° C ( 750 ° F to 1150 ° F ) , typically in the range of 460 ° C to 510 ° C ( 860 ° F to 950 ° F ) Exit from the casting machine at temperature. In addition, the continuous slab exiting the belt caster typically is 0.508 to 5.08 centimeters ( 0.2 to 2 inches ) , for example 0.508 to 2.54 centimeters ( 0.2 A thickness in the range of ˜1 inch ) . A typical slab thickness for a belt caster is about 1.524 to 2.223 centimeters ( 0.6 to 0.875 inches ) . The belt casting speed can range from 3.05 to 12.2 meters / minute ( 10-40 feet / minute ) depending on the thickness of the slab. For the purposes of formability and corrosion resistance, Al-Fe, in order to obtain a less comprising microstructures striations or lines of intermetallics such as Al-Fe-Mn or Mg 2 _Si, these casting conditions It is important to adhere to it. It should be noted that DC casting materials usually have a good or substantially uniform distribution of intermetallic particles. However, as previously noted, DC cast materials have a higher processing cost penalty than the subject continuous cast slabs. Thus, the present invention provides a continuous cast slab for forming into a sheet material with near DC casting properties in order to obtain cost savings and retain desired properties such as formability.

After exiting the caster, the slab 15 is directed to a rolling mill 30 where the slab is rolled there to form a rolled strip or flat product 34, preferably using a hot rolling mill. The hot rolling mill 30 reduces the controlled amount of slab thickness as the slab passes between each stand of rolls from one or more sets of oppositely opposed rolls 32. Become. Three sets of hot stands or rolls are illustrated in FIG. For example, slab 15 having a thickness of about .508 to 2.54 cm (0.2 to 1 inches) is about 0.0254 to 0.635 centimeters (.01 to .25 inches) Reduced to sheet product with thickness. Typically, for vehicle structural components or multiple panel members, the sheet product may be, for example, 0.0508-0.254 centimeters ( 0.02-0.1 ) or 0 , depending on the application. Have a thickness in the range of .508 centimeters ( 0.2 inches ) . The temperature of the slab entering the hot rolling mill 30 is typically about 371 ° C to 593 ° C ( 700 ° C to 1100 ° F ) if no heat is applied. Typically, the temperature of the sheet product exiting the rolling mill 30 is in the range of 177 ° to 371 ° C ( 350 ° F to 700 ° F ) . In another aspect of the invention, the slab from the casting machine 3 is 427 ° C. to 593 ° before hot rolling (not shown in FIG. 1) in order to increase the rolling temperature before hot rolling. It can be heated to a temperature of C ( 800 ° F. to 1100 ° F. ) . Thus, the slab entering the hot rolling mill may have a temperature of about 427 ° C to 593 ° C ( 800 ° F to 1100 ° F ) .

  The hot rolling mill 30 can reduce the thickness of the slab to about 60-95% of its original thickness, with a typical reduction rate of 75-95%. Depending on the end use of the sheet product, heat may be applied to the strip or slab between the hot stands in addition to or instead of heating prior to the hot rolling mill.

The temperature of the aluminum alloy sheet exiting the hot rolling mill is about 204 ° C to 427 ° C ( 400 ° F to 800 ° F ) depending on whether heat is input before or during hot rolling. Can be within the range.

After hot rolling, the hot rolled strip 34 may have a deformed structure and a deformed granular structure. The hot-rolled strip can have a partially or fully recrystallized grain structure with an optimal texture, depending on the prior heat input and rolling reduction. If the structure remains deformed and a recrystallized grain structure is required for the final product, annealing of the hot rolled strip 34 can be applied to facilitate recrystallization of the deformed structure. For example, it is important that an automotive application using the aluminum alloy of the present invention has a fine fully recrystallized particle structure with a random structure for the purpose of forming automotive parts according to the present invention. is there. Therefore, according to the present invention, it is preferable that the hot-rolled sheet is completely annealed for O-tempering in the annealing machine 40. The hot rolled sheet in the fully annealed state has a tensile strength in the range of 193 to 241 MPa ( 28 to 35 ksi ) , in the range of 82.7 or 89.6 to 120.7 MPa ( 12 or 13 to 17.5 ksi ) . It may have a yield strength and an elongation greater than 19%.

Referring to FIG. 1, it is illustrated that the hot rolled sheet product is directed to a continuous annealing machine 40 using a heater such as an infrared, solenoid, transverse flux induction heater. Found in the embodiment. Although any continuous heater can be used, an induction heater is preferred. If cold rolling of hot rolled strips (not shown in FIG. 1) is required, continuous annealing may also be required. Thus, in order to provide a fully recrystallized sheet with fine particles and highly desired forming properties, the hot or cold rolled strip is subjected to a 316 ° C to 593 ° C ( Within a temperature range of 600 ° F. to 1100 ° F. ) in the annealing machine 40. However, care must be taken that the sheet product is not over-annealed to the point where secondary recrystallization occurs. Secondary recrystallization is the growth of fine particles into undesirable coarse particles that are detrimental to formability.

As an alternative to continuous annealing, the hot rolled sheet can be batch annealed. That is, the hot rolled sheet 42 can be wound around the coil 48 or 49. These coils 48 or 49 are then placed in a furnace and 316 ° C. to 538 ° C. ( 600 ° F. over 2 to 10 hours to provide a rolled sheet in a fully annealed or O tempered state. -1000 ° F. ) . If the slab is hot rolled to a suitable gauge for forming, no further thermomechanical processing is required and the sheet is ready for the forming step. If the slab is hot rolled to an intermediate gauge, after annealing, the annealed material is subjected to cold rolling followed by further annealing to provide a sheet that is in O tempering for the forming operation. .

After hot rolling, the hot rolled sheet or flat product can be allowed to cool before other operations. For example, after hot rolling, the resulting strip 42 with or without annealing and cooling can be cold rolled into a sheet product having a final gauge (not shown in FIG. 1). Cold rolling may be accomplished by passing the strip 42 through several sets or stands including a cold rolling mill to provide the cold rolling required to produce the final gauge. Hot rolling can reduce the thickness of the strip 42 by 20% to 80% or 90%. The final gauge for automotive applications, 0.02-0.09, or even to 0.508 cm (0.1 inch), typically 0.0762 to 0.305 centimeters ( 0.03-0.12 inches ) . Cold rolling, rolling below 149 ° C. ( 300 ° F. ) , can be performed in a cold rolling line separate from the subject continuous casting and rolling line.

  After cold rolling to the final gauge, the sheet product is subjected to further annealing to ensure the required recrystallized structure and grain structure required to form the final automotive product.

  After hot rolling or annealing, the sheet 42 may be subjected to continuous rapid quenching such as a cold water quencher 50 prior to further operation. The quencher 50 can be placed at different locations in the process if used and shown after annealing.

Referring to FIG. 2, in an alternative process, the annealed hot rolled sheet may be cold rolled and followed by further annealing prior to forming. In a further embodiment or alternative process, after hot rolling, the sheet may be directly cold rolled and followed by annealing of the cold rolled sheet before being formed into a vehicle structural part or member. Cold rolled and annealed sheets along the rolling direction, a tensile strength in the range of 193~241MPa (28~35ksi), the range of 82.7~120.7MPa (12~17.5ksi) May have a yield strength within and an elongation greater than 19%. Further, the final gauge coil may go through one or a combination of steps, such as tension leveling, slitting, surface pretreatment, lubrication, or cutting to length, prior to the molding process.

Reference is made to FIGS. 3 and 4 as an example of a desired microstructure having good forming characteristics of a continuously cast (CC) aluminum sheet. FIG. 4 shows the microstructure of CC5754 alloy with controlled chemistry, while FIG. 3 shows that of a commercially used DC5754 alloy sheet. Both sheets are 0.153 centimeters ( 0.060 inches ) thick and are in an O tempered state. SEM examination of the formed particles during solidification, they Al-Fe, Al-Fe- Mn, and shows that it consists _Mg 2 Si. The grain structure of the CC sheet is substantially uniformly distributed with only minimal stripes or lines, whereas the intermetallic particles of the DC sheet are uniformly distributed. The intermetallic particle size of CC material ranges from about 0.1 to 7 μm, whereas that of DC material ranges from about 0.5 to 10 μm. The regional proportion of intermetallic particles is 0.43% for CC materials, while the regional proportion is 0.56% for DC materials. Also, using the optimum processing route, the CC sheet has a finer particle structure than the DC sheet. Particle size measurements show that CC material has an average particle size of 16.6 μm, whereas DC material has an average particle size of 17.8 μm. Thus, using chemical property control and process optimization, continuous casting techniques can produce microstructures similar to those produced by DC casting techniques, and are therefore required, for example, by the automotive industry. Provides molding properties.

  Referring now to FIG. 5, an automotive lift gate 100 provided as part of a sports multipurpose vehicle (SUV) is illustrated. The lift gate 100 consists of a bottom metal portion 102 and a window frame portion 104 covered with glass. The lift gate 100 is attached to the SUV roof 108 using a hinge 106 and is closed or secured to the vehicle using a handle 110. In general, the side 112, the bumper 114, and the roof 108 define an opening that is closed by a lift gate. In FIG. 6, the lift gate 100 is shown partially open and supported by a support member 116. Compared to steel, a lift gate fabricated from the aluminum alloy of the present invention can provide significant weight savings, which can be as much as 20 pounds, depending on the vehicle. In addition, lighter and cheaper struts can be used to open and support the lift gate, increasing weight savings. It should be noted that the strut 116 is fastened to the lift gate 100 at 118, which requires the aluminum alloy to have good forming characteristics to hold the threaded fastener.

  FIG. 7 shows an exploded view of an automobile lift gate structure consisting of an outer panel 120 and an inner panel 122 joined peripherally to provide a double panel lift gate structure. It will be appreciated that doors, hoods, fenders, and the like may take the same type of structure, i.e., inner and outer panels. Furthermore, it can be seen from FIGS. 7 and 8 that the outer panel 120 takes a generally curved and smooth shape. It can also be seen from FIG. 7 that the outer panel 120 structure shows the window frame 104 as an integral part of the bottom 102. Still referring to FIG. 7, the inner panel 122 includes a dish-shaped portion 124 and has a more complex design that may have raised channels and open portions (not shown), particularly when used as a door and hood. It will be noted that it is used. The inner panel with its dish-shaped and raised portions serves to increase the bending strength of the lift gate. Furthermore, the inner panel or outer panel can be molded from a single sheet using stamping between mating dies to provide the necessary structural features for the liftgate assembly. The outer panel is relatively smooth and curved, but as noted, the inner panel is typically shaped to form a channel 126 (FIG. 8) to provide increased strength to the window frame portion. Yes. The outer panel 120 may be constructed of steel or, for example, aluminum alloy AA6111 or AA5083. Its composition was provided in an aluminum association publication entitled "International Alloy Designs and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys" dated January 2001 and all of them. Is quoted here as a reference.

  FIG. 8 shows a cross-sectional view of a lift gate that utilizes an outer panel 120 that is edged or stitched to the inner panel 122. Thus, the outer panel 120 is relatively smooth and the inner panel 122 has a recessed area and uses channels around the window frame 104 for increased strength. The lift gate obtains its strength from two molded panels of double or multiple structure.

  The molded panel may include doors, hoods, trunk lids, wheels, and bumper backup bars, and may be formed from a flat aluminum alloy that is formed between mating dies to provide a three-dimensional structure. The double or multiple structures as depicted utilize a peripheral stitching or edging process to provide a vehicle structural member. However, other joining means may include welding, riveting, adhesive bonding. Thus, the inner panel and the outer panel can be joined by any of these methods, and such are envisioned. The stitching and edging process referred to is shown in FIG. 8 where the outer panel 120 is edged around the inner panel 122. Thus, the outer panel 120 must be able to be molded or bent 180 ° without cracking, in which case the radius of bending is about half the metal thickness.

  In some examples, the structural member may include a combination of steel and aluminum alloy, but such a structure does not provide the same weight savings.

  The alloys of the present invention are required to have good formability for yet another reason. That is, the hinge 106 and the support member 116 are preferably joined to, for example, a steel threaded fastener. Thus, it is preferable to use a metal fastener such as a steel fastener at 118 where the strut 116 is connected to the lift gate 100. Accordingly, the threaded fastener 130 is crimped to the sheet metal of the inner panel as shown in FIG. The crimping process must have the rigor of pulling the sheet metal around the shoulder 132 of the threaded fastener without forming a crack in the sheet metal. The locking of the threaded fasteners in the sheet metal must be sufficiently stiff to allow the bolts to be screwed into the fasteners through the struts. Crimping in this manner eliminates the need for welding and immediately allows aluminum to be joined to the steel threaded fastener for ease of processing. Crimping is alloy sensitive and if the iron is too high, the metal can crack during the crimping operation. Thus, for the purposes of crimping, it is preferred to keep iron below 0.25% by weight, preferably within the range of 0.05 or 0.1 to 0.2% by weight.

  Thus, an aluminum alloy vehicle part or member manufactured according to the above implementation provides a material with strength and formability for use as a vehicle or vehicle seat that can be formed into many different automotive structural members. .

  All ranges provided herein are intended to include all numbers within the range, as specifically shown, eg, 1-5 is 1.1, 1.2, 1 .3, or for example, 2, 3, 4 etc.

  The following examples further illustrate the examples of the present invention.

Example 3.267 wt% Mg, 0.201 wt% Mn, 0.080 wt% Si, 0.164 wt% Fe, 0.0020 wt% Cu, 0.004 wt% Cr, And an aluminum based alloy containing 0.024 wt% Zn is fed to a twin belt caster at a temperature of 682 ° C ( 1260 ° F ) and has a thickness of 2.223 centimeters ( 0.875 inch ) The slab was solidified to produce a slab and exited the caster at a temperature of 482 ° C ( 900 ° F ) . The slab was fed directly to three stand hot rolling mills and rolled to a final gauge of 0.254 centimeters ( 0.100 inch ) . The temperature at which the slab was introduced into the hot rolling mill was about 438 ° C. ( 820 ° F. ) , and the temperature exiting the rolling mill was about 271 ° C. ( 520 ° F. ) . The hot rolled sheet was wound around a coil. The coils were annealed at a temperature of 388 ° C. ( 730 ° F. ) for 4 hours in an annealing furnace. The annealed coil was strength leveled and separated to the required width, and the coil was then surface pretreated and lubricated. Material, in the rolling direction before forming into automotive parts, had ultimate tensile strength of 226MPa (32.8ksi), yield strength of 106.9MPa (15.5ksi), 21.4% of property of elongation. All of these characteristics met the requirements specified by the Aluminum for Automotive Body Sheet Panel published by the Aluminum Society. The material was formed into an internal structural panel and the threaded fastener was crimped into a sheet with satisfactory quality inspection. Therefore, the alloy can be cast into a twin belt casting machine, rolled into a sheet product, and stamped or formed into a structural part or member for an automobile having sufficient strength and formability.

  There is a continuous casting machine that can be used to envision a slab that can be thermomechanically processed to form a sheet product having properties for molding into a vehicle part or component.

  Although the presently preferred embodiments have been described, it is to be understood that the invention may be embodied in other ways within the scope of the appended claims.

It is the schematic which shows the continuous casting machine, the hot rolling mill, and the roll of sheet material. It is a flowchart which shows the step in this invention. It is an electron micrograph which shows the fine structure of a direct chill casting material. 2 is an electron micrograph showing the microstructure of a sheet material formed by continuous casting (CC) and rolling according to the present invention. It is the schematic which shows the rear hatch door or lift gate of a vehicle. It is a side view of the vehicle which opens and shows a rear door. It is a perspective view which shows the structural member of the separated rear hatch door. It is sectional drawing which shows the structural member by which both edge processing was carried out. FIG. 3 is a cross-sectional view showing a threaded fastener crimped to metal.

Claims (4)

A process for manufacturing the automotive member having an inner panel and an outer panel connected to form a multi-panel automotive member,
The inner panel has a threaded fastener that is securely crimped into the inner panel to bolt an accessory to the automotive member;
The inner panel is
(A) 2 . 7 to 3.6 wt% Mg, 0.1 to 0.4 wt% Mn, 0.02 to 0.2 wt% Si, 0.05 to 0.25 wt% Fe, up to 0.1 Providing a molten aluminum alloy containing wt% Cu, up to 0.25 wt% Cr, up to 0.2 wt% Zn, up to 0.15 wt% Ti, the balance being aluminum and inevitable impurities And steps to
(B) providing a continuous casting machine to continuously cast the molten aluminum alloy;
(C) casting the molten aluminum alloy into a slab having intermetallic particles of Al-Fe, Al-Fe-Mn, or Mg2Si;
(D) rolling the slab into a sheet product;
(E) so that the sheet product has a uniform distribution of the intermetallic particles, and Namasu step burn the sheet material in O temper condition,
(F) forming a portion of the sheet product in the O tempering into the inner panel by stamping to provide an inner panel having raised portions and recesses to provide rigidity to the inner panel;
(G) crimping at least one threaded fastener to the inner panel;
(H) providing an outer panel for coupling to the inner panel;
(I) formed by a process comprising the steps of: connecting the outer panel to the inner panel to provide the automotive member having a threaded fastener coupled to the automotive member.
process. A process for manufacturing the automotive member having an inner panel and an outer panel connected to form a multi-panel automotive member,
The inner panel has a threaded fastener that is securely crimped into the inner panel to bolt an accessory to the automotive member;
The inner panel is
(A) 2 . 7 to 3.6 wt% Mg, 0.1 to 0.4 wt% Mn, 0.02 to 0.2 wt% Si, 0.05 to 0.25 wt% Fe, up to 0.1 Providing a molten aluminum alloy containing wt% Cu, up to 0.25 wt% Cr, up to 0.2 wt% Zn, up to 0.15 wt% Ti, the balance being aluminum and inevitable impurities And steps to
(B) providing a continuous casting machine to continuously cast the molten aluminum alloy;
(C) the molten aluminum alloy has a thickness in the range of 0.51 centimeters to 5.08 centimeters ( 0.2 inches to 2 inches ) , and Al—Fe, Al—Fe—Mn, Or casting into a slab having Mg2Si intermetallic particles;
(D) a step of said slab to hot rolling hot rolled sheet product, heat rolling begins at a temperature range of 399 ° C~538 ° C (750 ° F ~1000 ° F), 204 Ending within a temperature range of ° C to 441 ° C ( 400 ° F to 825 ° F ) ;
(E) The hot rolled sheet product has a tensile strength in the range of 193 to 241 MPa (28 to 35 ksi), a yield strength in the range of 82.7 to 120.7 MPa (12 to 17.5 ksi), and 19%. It has a greater elongation than, and, to have a uniform distribution of the intermetallic particles, and Namasu step bake the hot rolled sheet product to an O temper condition,
(F) forming the sheet product in the O tempering into the inner panel by stamping to provide an inner panel having raised and recessed portions to provide rigidity to the inner panel;
(G) crimping at least one threaded fastener to the inner panel;
(H) providing an outer panel for coupling to the inner panel;
(I) formed by a process comprising the steps of: connecting the outer panel to the inner panel to provide the automotive member having a threaded fastener coupled to the automotive member.
process. A process for manufacturing the automotive member having an inner panel and an outer panel connected to form a multi-panel automotive member,
The inner panel has a threaded fastener that is securely crimped into the inner panel to bolt an accessory to the automotive member;
The inner panel is
(A) 2 . 7 to 3.6 wt% Mg, 0.1 to 0.4 wt% Mn, 0.02 to 0.2 wt% Si, 0.05 to 0.25 wt% Fe, up to 0.1 Providing a molten aluminum alloy containing wt% Cu, up to 0.25 wt% Cr, up to 0.2 wt% Zn, up to 0.15 wt% Ti, the balance being aluminum and inevitable impurities And steps to
(B) providing a continuous casting machine to continuously cast the molten aluminum alloy;
(C) the molten aluminum alloy has a thickness in the range of 0.51 centimeters to 5.08 centimeters ( 0.2 inches to 2 inches ) , and Al—Fe, Al—Fe—Mn, Or casting into a slab containing Mg2Si intermetallic particles;
(D) hot rolling the slab into a hot rolled sheet product;
(E) In order to provide a cold rolled sheet product, the hot rolled sheet product has a thickness in the range of 0.03 centimeters to 0.51 centimeters ( 0.01 inches to 0.2 inches ). Cold rolling,
(F) The cold rolled sheet product has a tensile strength in the range of 193 to 241 MPa (28 to 35 ksi), a yield strength in the range of 82.7 to 120.7 MPa (12 to 17.5 ksi), and 19%. Annealing the cold-rolled sheet product so as to have a greater elongation and a uniform distribution of the intermetallic particles, and providing an annealed sheet product ;
(G) forming the annealed sheet product into the inner panel;
( H ) crimping at least one threaded fastener to the inner panel;
( I ) providing an outer panel for coupling to the inner panel;
( J ) connecting the outer panel to the inner panel to provide the automotive member having a threaded fastener coupled to the automotive member.
process. A process for manufacturing the automotive member having an inner panel and an outer panel connected to form a multi-panel automotive member,
The inner panel has a threaded fastener that is securely crimped into the inner panel to bolt an accessory to the automotive member;
The inner panel is
(A) 2 . 7 to 3.6 wt% Mg, 0.1 to 0.4 wt% Mn, 0.02 to 0.2 wt% Si, 0.05 to 0.25 wt% Fe, up to 0.1 Providing a molten aluminum alloy containing wt% Cu, up to 0.25 wt% Cr, up to 0.2 wt% Zn, up to 0.15 wt% Ti, the balance being aluminum and inevitable impurities And steps to
(B) providing a continuous casting machine to continuously cast the molten aluminum alloy;
(C) the molten aluminum alloy has a thickness in the range of 0.51 centimeters to 5.08 centimeters ( 0.2 inches to 2 inches ) , and Al—Fe, Al—Fe—Mn, Or casting into a slab having Mg2Si intermetallic particles;
(D) hot rolling the slab into a hot rolled sheet product, the hot rolling starting within a temperature range of 399 ° C to 538 ° C ( 750 ° F to 1000 ° F ) ; Ending within a temperature range of 232 ° C to 441 ° C ( 450 ° F to 800 ° F ) ;
(E) annealing the hot rolled sheet product to provide an annealed sheet product;
(F) cold rolling the annealed sheet product to a thickness in the range of 0.03 centimeters to 0.51 centimeters ( 0.01 inches to 0.2 inches ) ;
(G) a tensile strength in the range of cold-rolled sheet product 193~241MPa (28~35ksi), yield strength in the range of 82.7~120.7MPa (12~17.5ksi), and 19% have a greater elongation than, and the Hiyakan圧Nobeshi over preparative product to have a uniform distribution of the intermetallic particles, to further annealed the cold rolled sheet product, between a further annealing cold Providing a rolled sheet product ;
(H) forming the further annealed cold rolled sheet into the inner panel;
(I) crimping at least one threaded fastener to the inner panel;
(J) providing an outer panel for coupling to the inner panel;
And (k) connecting the outer panel to the inner panel to provide the automotive member having a threaded fastener coupled to the automotive member.
process.

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