Magnesium alloy automobile front end upper cross beam and manufacturing method

Abstract

The invention relates to the technical field of vehicles, in particular to a magnesium alloy automobile front-end upper cross beam and a manufacturing method thereof.The magnesium alloy automobile front-end upper cross beam comprises a front-end upper cross beam body which is made of a magnesium alloy material and integrally formed through injection molding; a front bumper mounting plate, a left headlamp mounting hole, a right headlamp mounting hole, a decorative plate mounting groove, a wire harness fixing hole and an engine hood lock mounting hole are formed in the front end upper cross beam body, and through magnesium alloy materials, an integrated injection molding process and a hollow design, the product weight is reduced, and the performance is improved; compared with the front end upper cross beam made of all steel, the front end upper cross beam has the advantages that the investment quantity and cost of tool molds are reduced; the light weight of the product is realized, and the dimensional accuracy of the front-end upper cross beam is guaranteed; compared with a plastic upper cross beam, the magnesium alloy is better in yield strength and impact resistance, meets the performance requirements of the whole automobile, and solves the problems that an existing automobile front end upper cross beam is large in weight, low in product performance and not prone to meeting the performance requirements of the whole automobile.

Description

Technical Field

[0001] This invention belongs to the field of vehicle technology, and in particular relates to a magnesium alloy upper crossbeam for the front end of an automobile and its manufacturing method. Background Technology

[0002] The front upper crossbeam of a car is a crucial supporting and reinforcing structure in the front of the engine compartment, connecting important components such as the body, hood latches, bumper, and headlight brackets. Currently, front upper crossbeams are primarily manufactured using either all-steel sheet metal welding or plastic injection molding. Steel front upper crossbeams require stamping and welding of sheet metal, resulting in good mechanical properties but also significant drawbacks such as heavy weight, poor dimensional accuracy, and high tooling costs. Plastic front upper crossbeams are formed by injection molding of plastic particles, offering lighter weight and high dimensional accuracy in a single molding process. However, these products tend to have lower performance and may not easily meet the overall vehicle performance requirements. Summary of the Invention

[0003] In view of this, the present invention aims to provide a magnesium alloy automotive front-end upper crossbeam and its manufacturing method, so as to solve the problems of existing automotive front-end upper crossbeams being heavy, having low product performance, and being difficult to meet the overall vehicle performance requirements.

[0004] To achieve the above objectives, the technical solution created by this invention is implemented as follows: The first aspect of this invention provides a magnesium alloy automotive front upper crossbeam, comprising a front upper crossbeam body made of magnesium alloy and integrally injection molded; the front upper crossbeam body is provided with a front bumper mounting plate, a left headlight mounting hole, a right headlight mounting hole, a decorative panel mounting groove, a wiring harness fixing hole, and an engine hood lock mounting hole; the front bumper mounting plate is provided with multiple such holes spaced apart on the front surface of the front upper crossbeam body; the left headlight mounting hole and the right headlight mounting hole are respectively provided at opposite ends of the front upper crossbeam body along the extending direction of the front upper crossbeam body; the decorative panel mounting groove and the wiring harness fixing hole are provided on the upper surface of the front upper crossbeam body and are provided with multiple such holes spaced apart along the extending direction of the front upper crossbeam body; the engine hood lock mounting hole is provided on the same side as the front bumper mounting plate.

[0005] Furthermore, the front bumper mounting plate has through holes, and rivet nuts are respectively installed in the through holes, the left headlight mounting hole, and the right headlight mounting hole.

[0006] Furthermore, the bottom surfaces of the two ends of the front upper beam body are respectively provided with through holes, and bushings are coaxially arranged in the through holes.

[0007] Furthermore, the front upper crossbeam body is hollow, and the front upper crossbeam body is provided with reinforcing ribs. Both the front upper crossbeam body and the reinforcing ribs are made of magnesium alloy material and are integrally injection molded.

[0008] Another aspect of this invention provides a method for manufacturing a magnesium alloy automotive front-end upper crossbeam, applicable to the magnesium alloy automotive front-end upper crossbeam described in the first aspect above, comprising the following steps: S1. Mold preparation and parameter adjustment: Install the mold on the injection molding machine and adjust the injection molding parameters; S2. Semi-solid slurry preparation: Magnesium alloy AM60B particles are selected as raw materials. The magnesium alloy AM60B particles are fed into the semi-solid material preparation tube by negative pressure and gravity, and heated in the preparation tube in a closed manner. At the same time, the magnesium alloy particles are heated and melted by screw stirring to form a semi-solid slurry of solid and liquid two-phase mixture. Meanwhile, the mold in step S1 is preheated. After preheating, a release agent is sprayed into the mold cavity. S3. Injection Molding and Demolding: The semi-solid slurry prepared in step S2 is injected into the mold cavity in step S1. The injection is completed according to the set injection molding parameters. After injection molding, the mold slider is controlled to remove the core and then the mold is opened. S4. Product cooling and part removal: The front upper crossbeam body formed in the mold is taken out by the robot and placed on the conveyor belt. The cooling fan set above the conveyor belt is used to cool the formed front upper crossbeam body. After cooling, the front upper crossbeam body is transferred to the designated position. S5. Slag bag removal and edge trimming: Use hydraulic shears and air hammer to remove the slag bag on the front upper crossbeam body. Install the edge trimming mold on the hydraulic press, place the front upper crossbeam body after removing the slag bag in the edge trimming mold, and punch the product edge. S6. Rivet Nut Installation and Bushing Assembly: Use a rivet gun to install rivet nuts on the left headlight mounting hole, front bumper mounting plate, and right headlight mounting hole of the front upper crossbeam body. Then, manually install bushings in the through holes set on the bottom surface of both ends of the front upper crossbeam to complete the fabrication of the magnesium alloy automotive front upper crossbeam.

[0009] Furthermore, in step S1, the injection molding parameters include injection pressure, injection speed, and holding time, wherein the injection pressure is 50MPa~90MPa, the injection speed is 1~4m / s, and the holding time is 30s~50s.

[0010] Furthermore, in step S2, the mass percentage of the magnesium alloy AM60B particles includes magnesium, aluminum, zinc, manganese, silicon, copper, nickel, and iron, wherein the aluminum content is 5.5~6.5%, the zinc content is ≤0.20%, the manganese content is 0.24%~0.6%, the silicon content is ≤0.08%, the copper content is ≤0.008%, the nickel content is ≤0.001%, the iron content is ≤0.004%, and the balance is magnesium.

[0011] Furthermore, in step S2, the heating temperature is 570~630℃ and the heating time is 60~80s.

[0012] Furthermore, in step S2, the preheating temperature is 120℃~180℃.

[0013] Compared with the prior art, the present invention can achieve the following beneficial effects: By using magnesium alloy materials and a one-piece injection molding process, combined with a hollow design, the product weight is reduced while performance is improved. Compared to an all-steel front upper crossbeam, the number of tooling molds and costs are reduced. This achieves product lightweighting while ensuring the dimensional accuracy of the front upper crossbeam. Compared to a plastic upper crossbeam, magnesium alloy has better yield strength and impact resistance, meeting the performance requirements of the entire vehicle and solving the problem of existing automotive front upper crossbeams being heavy, having low performance, and not easily meeting the performance requirements of the entire vehicle. Attached Figure Description

[0014] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 A schematic diagram of the structure of the front upper crossbeam body provided for an embodiment of the present invention; Figure 2 A front structural schematic diagram of the front upper crossbeam body provided for an embodiment of the present invention; Figure 3 A flowchart illustrating the front-end upper crossbeam manufacturing method provided in an embodiment of the present invention.

[0015] Explanation of reference numerals in the attached figures: 1. Front upper crossbeam body; 2. Front bumper mounting plate; 21. Through hole; 3. Left headlight mounting hole; 4. Right headlight mounting hole; 5. Decorative panel mounting groove; 6. Wiring harness fixing hole; 7. Engine hood lock mounting hole; 8. Through hole; 9. Reinforcing rib. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and do not constitute a limitation thereof. Similar elements in different embodiments are referred to by associated similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of the invention. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, some operations related to the invention are not shown or described in the specification. This is to avoid obscuring the core parts of the invention with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0017] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined to form various implementations. Furthermore, the order of the steps or actions in the method description can be changed or adjusted in a manner readily apparent to those skilled in the art. Therefore, the various orders in the specification and drawings are merely for the clear description of a particular embodiment and do not imply a mandatory order, unless otherwise stated that a particular order must be followed.

[0018] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0019] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0020] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0021] like Figures 1 to 2As shown, the first aspect of this embodiment provides a magnesium alloy automotive front-end upper crossbeam, including a front-end upper crossbeam body 1. The front-end upper crossbeam body 1 is made of magnesium alloy AM60B particles and integrally injection molded using a semi-solid injection molding process. The front-end upper crossbeam body 1 is also provided with a front bumper mounting plate 2, a left headlight mounting hole 3, a right headlight mounting hole 4, a decorative panel mounting groove 5, a wiring harness fixing hole 6, and an engine hood lock mounting hole 7. The front bumper mounting plate 2 is disposed on the front end surface of the front-end upper crossbeam body 1 and is plate-shaped along the width direction of the front bumper mounting plate 2. The front bumper mounting plate 2 is used to connect with the front bumper to ensure the front bumper mounting position and to ensure the consistency of the front appearance of the vehicle and the collision protection effect. In this embodiment, six front bumper mounting plates 2 are spaced apart. The spaced distribution design can evenly distribute the impact force of the front bumper to the front-end upper crossbeam body 1, avoiding structural deformation caused by excessive force at a single point. The left headlight mounting hole 3 and the right headlight mounting hole 4 are respectively located on the upper surface of opposite ends of the front upper crossbeam body 1, extending along the front upper crossbeam body 1. Multiple left headlight mounting holes 3 and multiple right headlight mounting holes 4 are provided, and their positions fit tightly with the mounting interface of the headlight base, ensuring quick alignment of the headlights during assembly without additional adjustments, thus improving assembly efficiency. Simultaneously, the tight fit prevents headlight wobbling due to gaps during vehicle operation, preventing beam angle deviation. The decorative panel mounting groove 5 and the wiring harness fixing hole 6 are located on the upper surface of the front upper crossbeam body 1, and are spaced multiple times along the extension direction of the front upper crossbeam body 1. The decorative panel mounting groove 5 is designed along the width direction of the front upper crossbeam body 1 and connects to the mounting protrusion of the decorative panel through insertion, with rounded corners at the groove edge. The insertion and engagement of the decorative panel mounting groove 5 with the mounting protrusion achieves quick connection, ensuring the flatness and firmness of the assembled decorative panel and preventing abnormal noises during vehicle operation. The rounded corner structure eliminates the risk of sharp edges, preventing scratches to operators or damage to the decorative panel surface during assembly. Simultaneously, multiple spaced decorative panel mounting slots 5 provide segmented support according to the length of the decorative panel, ensuring more even stress distribution and effectively preventing warping and deformation after long-term use. The wiring harness fixing holes 6 engage with the hooks on the wiring harness cable ties, enabling quick positioning and fixing of the wiring harness without the need for additional connectors, simplifying the assembly process. This also ensures the wiring harness remains in a neat and orderly state, avoiding the risk of insulation damage caused by friction between the wiring harness and surrounding components. The hood lock mounting holes 7 are located on the same side as the front bumper mounting plate 2. This layout ensures that the force direction of the hood lock and the front bumper is consistent, improving the stability after the hood is closed.

[0022] In some embodiments, the front bumper mounting plate 2 has a through hole 21, and rivet nuts are respectively installed in the through hole 21, the left headlight mounting hole 3, and the right headlight mounting hole 4. The rivet nuts engage with the front bumper mounting plate 2, the left headlight mounting hole 3, and the right headlight mounting hole 4 to form a tight fixation. The rivet nuts improve the strength of the threaded connection in the holes and enhance the precision of the front assembly of the vehicle.

[0023] In some embodiments, the bottom surfaces of both ends of the front upper crossbeam body 1 are respectively provided with through holes 8 for connecting with the vehicle body connection parts, and bushings are coaxially arranged in the through holes 8. The bushings are placed in the through holes 8 and are interference-fitted with the through holes 8. The bushings effectively improve the wear resistance and impact resistance of the connection parts between the front upper crossbeam and the vehicle body, and further improve the reliability of the connection.

[0024] In some embodiments, the front upper crossbeam body 1 is hollow, and a reinforcing rib 9 is provided inside the front upper crossbeam body 1. Both the front upper crossbeam body 1 and the reinforcing rib 9 are made of magnesium alloy and are integrally injection molded. The hollow structure can further reduce weight while ensuring overall rigidity, and the reinforcing rib 9 can improve the bending stiffness of the front upper crossbeam body 1, effectively offsetting the strength loss caused by the hollow design. At the same time, the integral injection molding process makes the reinforcing rib 9 and the front upper crossbeam body 1 form a continuous load-bearing whole, improving the overall load-bearing capacity and fatigue resistance of the structure.

[0025] By using magnesium alloy materials and a one-piece injection molding process, combined with a hollow design, the product weight is reduced while performance is improved. Compared to an all-steel front upper crossbeam, this reduces the number and cost of tooling and molds, achieving product lightweighting while ensuring dimensional accuracy of the front upper crossbeam. Compared to a plastic upper crossbeam, the magnesium alloy automotive front upper crossbeam has superior yield strength and impact resistance, meeting the overall vehicle performance requirements and solving the problems of existing automotive front upper crossbeams being heavy, having low performance, and failing to meet overall vehicle performance requirements.

[0026] The second aspect of this invention provides a method for manufacturing a magnesium alloy upper crossbeam for the front end of an automobile, applicable to the magnesium alloy upper crossbeam for the front end of an automobile described in the first aspect above, such as... Figure 3 As shown, it includes the following steps: S1. Mold preparation and parameter adjustment: Install the mold on the injection molding machine and adjust the injection molding parameters; Specifically, after the mold is installed, the injection molding parameters are adjusted. These parameters include injection pressure, injection speed, and holding time. The injection pressure is 50MPa~90MPa, the injection speed is 1~4m / s, and the holding time is 30s~50s. An injection pressure of 50MPa~90MPa ensures that the semi-solid slurry fully fills the complex structure of the mold cavity, avoiding material shortage defects. An injection speed of 1~4m / s ensures the filling efficiency and stability of the semi-solid slurry, reducing air bubble entrapment and shortening the filling time. A holding time of 30s~50s compensates for the cooling shrinkage of the semi-solid slurry, achieving high-quality product molding.

[0027] S2. Semi-solid slurry preparation: Magnesium alloy AM60B particles are selected as raw materials. The magnesium alloy AM60B particles are fed into the semi-solid material preparation tube by negative pressure and gravity, and heated in the preparation tube in a closed manner. At the same time, the magnesium alloy particles are heated and melted by screw stirring to form a semi-solid slurry of solid and liquid two-phase mixture. Meanwhile, the mold in step S1 is preheated. After preheating, a release agent is sprayed into the mold cavity. Specifically, the mass percentage of the AM60B magnesium alloy particles includes magnesium, aluminum, zinc, manganese, silicon, copper, nickel, and iron. The aluminum content is 5.5-6.5%, zinc ≤0.20%, manganese 0.24%-0.6%, silicon ≤0.08%, copper ≤0.008%, nickel ≤0.001%, and iron ≤0.004%, with the balance being magnesium. These components give the AM60B magnesium alloy high specific strength and good corrosion resistance, maintaining stable performance in harsh environments such as humid and acidic / alkaline conditions. Its yield strength is greater than 110 MPa, enabling it to withstand large loads. The material elongation is greater than 10%, exhibiting good impact resistance. During the heating process, the heating temperature is 570-630℃, and the heating time is 60-80 seconds. Simultaneously, the oxide layer on the surface of the AM60B magnesium alloy particles is broken up through screw stirring and shearing, promoting uniform mixing of the solid and liquid phases, ultimately forming a semi-solid slurry. Semi-solid slurry has good fluidity and can maintain morphological stability, meaning that shrinkage defects will not occur after molding.

[0028] It should be noted that semi-solid refers to a solid-liquid mixture in which a certain proportion of solid components are uniformly suspended in a liquid metal mother liquor. The solid components in the melt are suspended in the liquid matrix in a near-spherical or cellular form and cannot form a dendritic structure. This semi-solid metal slurry has rheological properties, that is, it has good low-temperature fluidity and is easy to form into products by low-temperature molding.

[0029] The preheating process can be carried out by electric heating, with the preheating temperature set at 120℃~180℃. After preheating, a release agent is sprayed into the mold cavity. The release agent can be sprayed using an atomization spraying process. A high-temperature resistant silicone oil-based water-based release agent is selected and sprayed evenly in a full-coverage manner to ensure that a uniform film of 0.01~0.03mm thick is formed on the surface of the cavity, which not only prevents the product from sticking to the mold but also does not affect the surface quality of the product.

[0030] S3. Injection Molding and Demolding: The semi-solid slurry prepared in step S2 is injected into the mold cavity in step S1. The injection is completed according to the set injection molding parameters. After injection molding, the mold slider is controlled to move so that the core is pulled out and then the mold is opened.

[0031] Specifically, the semi-solid slurry is injected rapidly at an injection pressure of 50MPa~90MPa and an injection speed of 1~4m / s to prevent premature solidification within the mold cavity. After injection, the pressure is maintained for 30s~50s. After the pressure is maintained, the mold slide is first retracted to remove the core, and then the product is separated from the bottom of the cavity by the components built into the mold. Finally, the mold is opened.

[0032] S4. Product Cooling and Removal: The front upper crossbeam body 1 formed in the mold is removed by a robotic arm and placed on a conveyor belt. The cooling fan above the conveyor belt is used to cool the front upper crossbeam body 1. After cooling, the front upper crossbeam body 1 is transferred to the designated position.

[0033] Specifically, after mold opening, a robotic arm removes the formed front upper crossbeam body 1 using vacuum suction and mechanical clamping, and places it on a conveyor belt. The front upper crossbeam body 1 remains horizontal on the conveyor belt, and a cooling fan is installed above the conveyor belt to cool the front upper crossbeam body 1. After cooling, the front upper crossbeam body 1 is then picked up by the robotic arm and transferred to the unloading platform for storage.

[0034] S5. Slag removal and edge trimming: Use hydraulic shears and air hammer to remove the slag from the front upper crossbeam body 1. Install the edge trimming mold on the hydraulic press, place the front upper crossbeam body 1 after removing the slag into the edge trimming mold, and punch the product edge.

[0035] Specifically, before removing the slag bale, the front upper crossbeam body 1 is fixed. Then, the larger slag bales on the front upper crossbeam body 1 are cut using hydraulic shears. The remaining smaller slag pieces and flash are then removed using a pneumatic hammer with a rubber hammer head to gently tap and remove them, preventing deformation of the front upper crossbeam body 1 due to external impact. After removing the slag bale, the front upper crossbeam body 1 is placed into a trimming mold installed on a 200t hydraulic press and fixed. The hydraulic press uses a punching pressure of 100-130t to punch away the injection-molded flash from the edges of the front upper crossbeam body 1. After punching, the front upper crossbeam body 1 is removed and transferred to the next process.

[0036] S6. Rivet Nut Installation and Bushing Assembly: Use a rivet gun to install rivet nuts on the left headlight mounting hole 3, front bumper mounting plate 2 and right headlight mounting hole 4 of the front upper crossbeam body 1. Then, manually install bushings in the through holes 8 set on the bottom surface of both ends of the front upper crossbeam body 1 to complete the fabrication of the magnesium alloy automotive front upper crossbeam.

[0037] Specifically, before installing the rivet nuts, clean the left headlight mounting hole 3, the through hole 21 of the front bumper mounting plate 2, and the right headlight mounting hole 4 to ensure the hole walls are smooth and free of impurities. Select a suitable rivet nut according to the hole diameter, align the rivet gun head with the rivet nut, insert it into the hole, and start the rivet gun to deform the nut through axial tension, tightly engaging it with the front upper crossbeam body 1 to form a firm connection. When assembling the bushing, place the bushing into the through hole 8, ensuring its outer diameter is interference-fitted with the through hole 8. After the bushing is installed, the fabrication of the magnesium alloy automotive front upper crossbeam is complete.

[0038] In actual use, the mold is first mounted on the injection molding machine, and then the injection pressure is adjusted to 50MPa~90MPa, the injection speed to 1~4m / s, and the holding time to 30s~50s. Magnesium alloy AM60B particles are selected and then fed into the semi-solid material preparation tube under negative pressure and gravity. The tube is then heated in a sealed environment at 570~630℃ for 60~80s, and a semi-solid slurry is formed by stirring and shearing with a screw. Simultaneously, the mold is preheated to 120℃~180℃. After preheating, a high-temperature resistant silicone oil-based water-based release agent is sprayed, and then the semi-solid slurry is injected. After injection, the mold is held under pressure for 30s~50s. After the holding time, the mold slider is first retracted to remove the core, and then the front upper crossbeam body 1 is separated from the bottom surface of the cavity by components built into the mold. Finally, the mold is opened. A robotic arm then uses vacuum suction and mechanical clamping to remove the part, placing the front upper crossbeam body 1 onto a conveyor belt. After being cooled by a fan, it is transferred to the unloading platform. The front upper crossbeam body 1 is fixed, and the slag bag is removed using hydraulic shears and an air hammer. Then, the edges are punched with a 200t hydraulic press and a cutting die at a pressure of 100~130t. Finally, the left headlight mounting hole 3, the through hole 21 of the front bumper mounting plate 2, and the right headlight mounting hole 4 are cleaned. The matching rivet nuts are installed, and the bushings are manually pressed in to complete the fabrication of the magnesium alloy automotive front upper crossbeam.

[0039] Although embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

[0040] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A magnesium alloy upper crossbeam for the front end of an automobile, characterized in that, The device includes a front upper crossbeam body, which is made of magnesium alloy and integrally injection molded. The front upper crossbeam body has a front bumper mounting plate, a left headlight mounting hole, a right headlight mounting hole, a trim panel mounting groove, a wiring harness fixing hole, and an engine hood lock mounting hole. Multiple front bumper mounting plates are spaced apart on the front surface of the front upper crossbeam body. The left and right headlight mounting holes are located at opposite ends of the front upper crossbeam body along its extension direction. The trim panel mounting groove and the wiring harness fixing hole are located on the upper surface of the front upper crossbeam body and are spaced apart along its extension direction. The engine hood lock mounting hole is located on the same side as the front bumper mounting plate.

2. The magnesium alloy upper crossbeam for the front end of an automobile according to claim 1, characterized in that: The front bumper mounting plate has through holes, and rivet nuts are respectively installed in the through holes, the left headlight mounting hole and the right headlight mounting hole.

3. The magnesium alloy upper crossbeam for the front end of an automobile according to claim 1, characterized in that: The bottom surfaces of both ends of the front upper beam body are respectively provided with through holes, and bushings are coaxially arranged in the through holes.

4. The magnesium alloy upper crossbeam for the front end of an automobile according to claim 1, characterized in that: The front upper crossbeam body is hollow, and the front upper crossbeam body is provided with reinforcing ribs. Both the front upper crossbeam body and the reinforcing ribs are made of magnesium alloy material and are integrally injection molded.

5. A method for manufacturing a magnesium alloy upper crossbeam for the front end of an automobile, characterized in that, The method applied to a magnesium alloy automotive front end upper crossbeam according to any one of claims 1-4 includes the following steps: S1. Mold preparation and parameter adjustment: Install the mold on the injection molding machine and adjust the injection molding parameters; S2. Semi-solid slurry preparation: Magnesium alloy AM60B particles are selected as raw materials. The magnesium alloy AM60B particles are fed into the semi-solid material preparation tube by negative pressure and gravity, and heated in the preparation tube in a closed manner. At the same time, the magnesium alloy particles are heated and melted by screw stirring to form a semi-solid slurry of solid and liquid two-phase mixture. Meanwhile, the mold in step S1 is preheated. After preheating, a release agent is sprayed into the mold cavity. S3. Injection Molding and Demolding: The semi-solid slurry prepared in step S2 is injected into the mold cavity in step S1. The injection is completed according to the set injection molding parameters. After injection molding, the mold slider is controlled to remove the core and then the mold is opened. S4. Product cooling and part removal: The front upper crossbeam body formed in the mold is taken out by the robot and placed on the conveyor belt. The cooling fan set above the conveyor belt is used to cool the formed front upper crossbeam body. After cooling, the front upper crossbeam body is transferred to the designated position. S5. Slag bag removal and edge trimming: Use hydraulic shears and air hammer to remove the slag bag on the front upper crossbeam body. Install the edge trimming mold on the hydraulic press, place the front upper crossbeam body after removing the slag bag in the edge trimming mold, and punch the product edge. S6. Rivet Nut Installation and Bushing Assembly: Use a rivet gun to install rivet nuts on the left headlight mounting hole, front bumper mounting plate, and right headlight mounting hole of the front upper crossbeam body. Then, manually install bushings in the through holes set on the bottom surface of both ends of the front upper crossbeam to complete the fabrication of the magnesium alloy automotive front upper crossbeam.

6. The method for manufacturing a magnesium alloy automotive front-end upper crossbeam according to claim 5, characterized in that: In step S1, the injection molding parameters include injection pressure, injection speed and holding time, wherein the injection pressure is 50MPa~90MPa, the injection speed is 1~4m / s and the holding time is 30s~50s.

7. The method for manufacturing a magnesium alloy upper crossbeam for the front end of an automobile according to claim 5, characterized in that: In step S2, the mass percentage of the magnesium alloy AM60B particles includes magnesium, aluminum, zinc, manganese, silicon, copper, nickel, and iron, wherein the aluminum content is 5.5~6.5%, the zinc content is ≤0.20%, the manganese content is 0.24%~0.6%, the silicon content is ≤0.08%, the copper content is ≤0.008%, the nickel content is ≤0.001%, the iron content is ≤0.004%, and the balance is magnesium.

8. The method for manufacturing a magnesium alloy upper crossbeam for the front end of an automobile according to claim 5, characterized in that: In step S2, the heating temperature is 570~630℃ and the heating time is 60~80s.

9. The method for manufacturing a magnesium alloy upper crossbeam for the front end of an automobile according to claim 5, characterized in that: In step S2, the preheating temperature is 120℃~180℃.

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