Extrusion casting and tailor-welding integrated forming method and mold

Abstract

The invention relates to the technical field of casting, and provides an extrusion casting and tailor-welding integrated forming method and mold. The extrusion casting and tailor-welding integrated forming method comprises the steps that a tailor-welding joint area of a to-be-cast part is determined, and a transition part is manufactured; the transition parts are placed in the die, and a cavity of the die is divided into a plurality of sub-cavities through the transition parts; the multiple sub-cavities are filled with molten metal, sub-parts are formed through mold filling, and the outer surfaces of the sub-parts and the outer surfaces of the transition parts are melted and connected to form welding seams; and demolding the part, and reinforcing and welding along a welding seam. According to the extrusion casting and tailor-welding integrated forming method, the multiple sub-cavities are filled with liquid at the same time, so that the situation that the flow path of molten metal is too long can be avoided, regular welding seams can be formed between the sub-parts and the transition parts, then disordered joint before flowing of the molten metal is avoided, and meanwhile the joint strength and plasticity can be improved through welding of the welding seams.

Description

Technical Field

[0001] The present disclosure relates to the field of casting technology, and in particular to an extrusion casting and welding integrated molding method and a mold. Background Art

[0002] At present, the widespread application of aluminum alloy parts in car bodies has shown great potential and broad prospects. Especially in recent years, the casting technology of integrated large-scale thin-walled car body parts has been increasingly widely used in car bodies. Among them, high-pressure casting is prone to defects such as air entrapment and shrinkage holes, low yield rate, and inability to achieve heat treatment, resulting in low overall mechanical properties and low yield rate. The parts formed by extrusion casting have fine structure, can be heat-treated, and have better mechanical properties. They have been used to a certain extent in the production of miniaturized thick-walled parts. However, in the manufacturing field of large-scale integrated thin-walled parts, this process still faces challenges.

[0003] Such parts often have complex spatial modeling structures, which increases the flow resistance of the molten metal during the molding process and makes it difficult to achieve full mold filling. At the same time, due to the thin wall thickness of the parts, the heat exchange between the molten metal and the mold is extremely intense, which can easily lead to the problem of too fast solidification speed and cause cold shut. Even if there are some methods of opening multiple gates for pouring, the flow front of the molten metal is prone to disordered joints, making it difficult to reinforce the joints later. Summary of the invention

[0004] In order to solve the above technical problems or at least partially solve the above technical problems, the present disclosure provides an extrusion casting and welding integrated molding method and a mold.

[0005] A first aspect of the present disclosure provides an extrusion casting and welding integrated molding method, comprising the following steps:

[0006] S1, determining a welding joint area of ​​a part to be cast, and manufacturing a transition part according to the shape of the part to be cast corresponding to the welding joint area;

[0007] S2, placing the transition part in the mold, and dividing the mold cavity of the mold into a plurality of sub-cavities by the transition part;

[0008] S3, filling the plurality of sub-cavities with molten metal and forming a plurality of sub-parts, wherein the sub-parts are melted and joined with the outer surface of the transition part to form a welded seam;

[0009] S4, demoulding the sub-component and the transition part, and welding them along the weld seam.

[0010] Optionally, the following steps are further included between step S2 and step S3:

[0011] Preheating the mold as a whole;

[0012] The area of ​​the mold corresponding to the transition part is locally heated, and / or the transition part is energized to heat the transition part to a semi-solidified state and keep the state warm.

[0013] Optionally, the step S3 specifically includes:

[0014] S31, filling the molten metal at one end of the sub-mold cavity away from the transition part, until the molten metal fills the entire sub-mold cavity in a direction toward the transition part.

[0015] Optionally, the step S31 specifically includes:

[0016] The piston of the squeeze casting equipment is set to fill the molten metal into the plurality of sub-cavities at a preset speed, wherein the preset speed of the piston is between 0.05 m / s and 4.0 m / s.

[0017] Optionally, after step S31, the following steps are further included:

[0018] S32. Before the molten metal solidifies, the pressure of the piston of the extrusion casting equipment is increased to a preset pressure and pressure-maintaining and shrinkage-compensating is performed, wherein the preset pressure of the piston is between 80 MPa and 300 MPa.

[0019] Optionally, the step S3 specifically includes:

[0020] The sub-component is formed by filling the mold with aluminum alloy liquid.

[0021] Optionally, the step S1 specifically includes:

[0022] S11, determining the welding joint area;

[0023] S12, determining the shape of the transition part according to the welding joint area;

[0024] S13, filling the mold with molten metal whose strength after filling is higher than that of the sub-part according to the determined shape to form the transition part.

[0025] A second aspect of the present disclosure provides a mold, the mold is used to process the part to be cast according to any one of the above-mentioned methods of squeeze casting and tailor-welding integrated molding;

[0026] The mold includes an upper mold, a lower mold and multiple extrusion sliders, the multiple extrusion sliders are arranged on the lower mold and together form the cavity, and the upper mold is provided with multiple pouring systems, and the multiple pouring systems are connected to the multiple sub-cavities in a one-to-one correspondence.

[0027] Optionally, a heating device is provided on the upper die and the lower die in the area corresponding to the transition part.

[0028] Optionally, the pouring system is arranged at an end of the corresponding sub-cavity away from the transition part.

[0029] Compared with the prior art, the technical solution provided by the embodiments of the present disclosure has the following advantages:

[0030] The extrusion casting and welding integrated molding method provided by the present invention comprises the following steps: determining the welding joint area of ​​the casting part, and making a transition part according to the shape of the part to be cast corresponding to the welding joint area; placing the transition part in the mold, and dividing the mold cavity into a plurality of sub-cavities by the transition part; filling the plurality of sub-cavities with molten metal and filling them into a plurality of sub-parts, and the sub-parts and the outer surface of the transition part are melted and joined to form a welding seam; demolding the sub-parts and the transition part, and welding along the welding seam, by arranging the transition part in the mold, the mold cavity can be divided into a plurality of sub-cavities, and by simultaneously filling the plurality of sub-cavities with molten metal Filling the cavity with liquid can avoid the metal liquid flow being too long, avoid defects such as cold shut and insufficient pouring, improve the metal liquid filling capacity of complex thin-walled parts, improve casting performance, and help the extrusion casting of large-sized or ultra-large-sized integrated thin-walled parts; at the same time, a regular weld seam can be formed between the sub-parts and the transition parts to avoid the problem of disordered joints at the front of the metal liquid flow, which makes it difficult to reinforce the joints in the later stage. For the weld seams produced by casting, through reinforcement welding, the aluminum alloy grains can be further refined, the weld seam joint strength and plasticity can be increased, the reliability and consistency of the welding parts can be ensured, and the overall mechanical properties of the parts can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0033] Figure 1 A step diagram of an extrusion casting and welding integrated molding method according to an embodiment of the present invention;

[0034] Figure 2 A schematic structural diagram of a mold according to an embodiment of the present invention;

[0035] Figure 3 A schematic diagram of the flow of molten metal according to an embodiment of the present invention;

[0036] Figure 4 It is a schematic diagram of the installation of an extrusion slider according to an embodiment of the present invention;

[0037] Figure 5 An exploded view of a mold according to an embodiment of the present invention;

[0038] Figure 6 It is a schematic structural diagram of a demoulding sub-part and a transition part according to an embodiment of the present invention;

[0039] Figure 7 FIG. 1 is a schematic diagram of welding at a weld seam according to an embodiment of the present invention.

[0040] In the figure: 1. part to be cast; 11. transition part; 12. sub-part; 13. weld seam; 14. weld seam; 15. casting block; 2. mold; 21. sub-cavity; 22. upper mold; 23. lower mold; 24. extrusion slide; 25. casting system; 251. barrel; 252. casting channel. DETAILED DESCRIPTION

[0041] In order to more clearly understand the above-mentioned objectives, features and advantages of the present disclosure, the scheme of the present disclosure will be further described below. It should be noted that the embodiments of the present disclosure and the features in the embodiments can be combined with each other without conflict.

[0042] In the following description, many specific details are set forth to facilitate a full understanding of the present disclosure, but the present disclosure may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present disclosure, rather than all of the embodiments.

[0043] The following is a detailed description of the extrusion casting and welding integrated molding method and mold through specific embodiments:

[0044] Reference Figures 1 to 7 As shown, some embodiments of the present invention provide an extrusion casting and welding integrated molding method, comprising the following steps: S1, determining the welding joint area of ​​the part 1 to be cast, and making a transition part 11 according to the shape of the part 1 to be cast corresponding to the welding joint area; S2, placing the transition part 11 in the mold 2, and dividing the cavity of the mold 2 into a plurality of sub-cavities 21 through the transition part 11; S3, filling the plurality of sub-cavities 21 with molten metal through the pouring system 25 and filling them into a plurality of sub-parts 12, and the sub-parts 12 and the outer surfaces of the transition part 11 are melted and joined to form a weld seam 13; S4, demolding the sub-parts 12 and the transition part 11, and welding along the weld seam 13.

[0045] In specific implementation, by arranging a transition part 11 in the mold 2, the cavity of the mold 2 can be divided into multiple sub-cavities 21. By filling the multiple sub-cavities 21 with liquid at the same time, the molten metal flow can be prevented from being too long, and defects such as cold shut and insufficient pouring can be avoided, thereby improving the molten metal filling capacity of complex thin-walled parts and improving the casting performance, which is helpful for the extrusion casting of large-sized or ultra-large-sized integrated thin-walled parts. At the same time, a regular weld seam 13 can be formed between the sub-part 12 and the transition part 11 to avoid the problem of disordered joints at the front of the molten metal flow, which makes it difficult to reinforce the joints in the later stage. For the weld seam 13 produced by casting, by performing reinforcement welding, the aluminum alloy grains can be further refined, the joint strength and plasticity of the weld seam 13 can be increased, the reliability and consistency of the welding part can be ensured, and the overall mechanical properties of the part can be improved.

[0046] It is understandable that after the casting, the transition part 11 is directly formed as a part of the casting part. Since the transition part 11 is different from the casting molten metal in material, hardness or other aspects, when the molten metal flows to the surface of the transition part 11, a sub-part 12 whose surface is tightly connected to the transition part 11 can be formed. However, the strength of the welded position between the transition part 11 and the sub-part 12 may be lower than that of the integrally cast part. By welding and reinforcing with the adjacent sub-parts 12, an integrated large-scale body part can be obtained. The welding method can be stir friction welding to form a weld 14 with high connection strength at the weld seam 13 to ensure the structural strength.

[0047] That is to say, the present invention divides a large overall cavity into multiple sub-cavities 21 with smaller volumes, so that the aluminum alloy molten metal can easily fill the sub-cavities 21, eliminating the defect of the traditional method of using a single cavity to fill from one end, which causes a large flow and unsuccessful filling. The sub-cavities 21 have a small internal volume, so the molten metal is easy to flow, with low resistance, and are not easy to solidify and cold shut; and the molten metal has a short flow in each sub-cavity 21, and when pressurized to compensate for shrinkage, the pressure is easily transmitted to the inside of the sub-cavity 21, thereby eliminating shrinkage defects, making the structure more dense and the parts stronger. Secondly, by pre-setting the transition part 11, the molten metal will not generate turbulent flow and cause a complex joining trajectory, so that the shape of the weld seam 13 is very regular, so stir friction welding can be used to strengthen the weld seam 13.

[0048] Reference Figure 2 and Figure 3As shown, between step S2 and step S3, the following steps are further included: preheating the mold 2 as a whole, locally heating the area of ​​the mold 2 corresponding to the transition part 11, and / or applying power to the transition part 11 to heat the transition part 11 to a semi-solidified state and keep it warm, wherein the solid phase ratio of the transition part 11 in the semi-solidified state is greater than or equal to 40%. It can be understood that the semi-solid transition part 11 is conducive to melting and welding with the adjacent sub-parts 12, thereby improving the bonding strength and ensuring the integrated performance of the casting part.

[0049] Specifically, high voltage electricity is applied to the transition part 11 to heat it by utilizing its own resistance, or the transition part 11 is locally heated by a heating device on the mold 2 to facilitate subsequent welding and joining.

[0050] In some embodiments, step S3 specifically includes: S31 , filling the end of the sub-mold cavity 21 away from the transition part 11 with molten metal until the molten metal fills the entire sub-mold cavity 21 in a direction toward the transition part 11 .

[0051] Reference Figure 3 As shown in the figure, after the molten metal enters the sub-cavity 21 through the pouring system 25, it flows from the end away from the transition part 11 in the direction toward the transition part 11, that is, the molten metal flows along Figure 3 The filling is respectively carried out toward the transition part 11 in the direction indicated by the middle arrow until the entire sub-cavity 21 is filled. The filling process of the molten metal in each sub-cavity 21 is short, the filling capacity is high, and the molding effect is good.

[0052] Specifically, step S31 specifically includes: setting the piston of the squeeze casting device to fill the molten metal into the multiple sub-cavities 21 at a preset speed. It can be understood that the piston can squeeze the molten metal at a uniform speed to ensure that all the molten metal is pressed into the cavity of the mold 2. The preset speed of the piston is between 0.05m / s and 4.0m / s.

[0053] It can be understood that the extrusion casting and welding integrated molding method disclosed in the present invention is suitable for large thin-walled car body parts. According to relevant textbooks and technical manuals, the filling speed during direct extrusion casting (i.e., the speed at which the piston squeezes the molten metal) is generally selected between 0.05m / s and 0.1m / s, and the filling speed during indirect extrusion casting is generally selected between 0.5m / s and 1.5m / s. In other words, the preset speed of the piston should be at least greater than or equal to 0.05m / s to ensure smooth filling of the molten metal.

[0054] Of course, when the piston moves to squeeze the molten metal for filling, the thicker the wall, the slower the filling speed should be, the thinner the wall, the faster the filling speed should be, the smaller the part, the slower the filling speed should be, the larger the part, the faster the filling speed should be, and for large thin-walled parts, the preset speed of the piston in the present disclosure should be less than or equal to 4.0 m / s. With this setting, the movement speed of the piston will not be too high, and while ensuring the filling of the molten metal, the power driving the piston movement can be avoided from being wasted, thereby improving the filling efficiency and ensuring the filling effect.

[0055] Furthermore, after step S31, the following further includes: S32, before the molten metal solidifies, increasing the pressure of the piston of the squeeze casting equipment to a preset pressure and performing pressure-maintaining and shrinkage-feeding to perform solidification and shrinkage-feeding treatment, which can eliminate shrinkage defects and increase the density of the parts until the metal solidifies, and also help to form a tightly joined weld 13 between the molten metal and the transition part 11. The preset pressure of the piston is between 80 MPa and 300 MPa.

[0056] According to the type of alloy and the liquid forging coefficient, for the aluminum alloy extrusion casting process, the preset pressure of the piston is P=k1*k2, where k1=80~100MPa, the direct extrusion casting coefficient k2=1~1.5, and the corresponding preset pressure is between 80MPa and 150MPa; the indirect extrusion casting coefficient k2=1.5~2, and the corresponding preset pressure is between 150MPa and 200MPa. In other words, the preset pressure of the piston should be at least greater than or equal to 80MPa to ensure smooth filling of the molten metal.

[0057] Of course, for large thin-walled parts, the preset pressure of the piston disclosed in the present invention should be less than or equal to 300 MPa to complete the extrusion casting of large or extra-large parts, and be able to adapt to more advanced equipment to ensure the filling efficiency of the molten metal.

[0058] Of course, it should be noted that the transition part 11 will be able to divide the mold cavity into a plurality of sub-cavities 21, and the shrinkage compensation process in each sub-cavity 21 is shorter, which is conducive to pressure maintenance and shrinkage compensation, and can improve casting performance.

[0059] In some embodiments, between step S1 and step S2, the following step is further included: cleaning the surface of the transition part 11 to ensure that there are no impurities such as oxide scale and oil stains. This arrangement can ensure the bonding performance between the transition part 11 and the sub-part 12 after casting.

[0060] In some embodiments, the step S3 specifically includes: using aluminum alloy molten metal to fill the mold to form the sub-part 12, so that the aluminum alloy molten metal can fill the filling components to ensure the product effect after filling.

[0061] Further, step S1 specifically includes: S11, determining the welding joint area; S12, determining the shape of the transition part 11 according to the welding joint area; S13, filling the mold with molten metal whose strength after filling is higher than that of the sub-part 12 according to the determined shape to form the transition part 11.

[0062] That is to say, the present disclosure can obtain a transition part 11 with higher structural strength by changing the material of the transition part 11. Specifically, it can be a deformed aluminum alloy molten metal with higher strength than the cast aluminum alloy. By setting the transition part 11 at a specific position, the final cast part can have structural and strength differences in spatial distribution, and thus different mechanical properties can be given to different areas of the cast part to meet diverse design requirements. That is, the final cast part after forming has a certain strength gradient difference in spatial distribution, thereby meeting the strength customization requirements.

[0063] In specific implementation, the welding joint area can be determined through CAE simulation analysis or based on design requirements, and the transition part 11 can be designed according to the welding joint area.

[0064] Of course, the transition part 11 can also increase the structural strength in other ways, which is not limited in the present disclosure and can be specifically configured according to actual needs.

[0065] Specifically, the welding joint area in step S11 can be the flow convergence state and position of the multi-cavity metal liquid in the mold 2, or it can be a local area with different strength requirements based on the structural design space of the casting part. Further, the transition part 11 is fixedly arranged on the lower mold 23 to prevent displacement during the pouring process, thereby ensuring that the position of the transition part 11 can completely correspond to the welding joint area on the casting part, thereby ensuring the structural performance of the casting part.

[0066] Some other embodiments of the present disclosure provide a mold 2, which is used to process a part to be cast 1 according to an extrusion casting and welding integrated molding method as in any of the above embodiments.

[0067] Specifically, refer to Figure 4 and Figure 5 As shown, the mold 2 includes an upper mold 22, a lower mold 23 and a plurality of extrusion sliders 24. The plurality of extrusion sliders 24 are all arranged on the lower mold 23 and together form a cavity. The upper mold 22 is provided with a plurality of pouring systems 25. The plurality of pouring systems 25 are connected to the plurality of sub-cavities 21 in a one-to-one correspondence so that the sub-cavities 21 can be poured through the pouring systems 25.

[0068] In a specific implementation, a receiving groove for receiving the extrusion slider 24 is formed on the lower mold 23. The extrusion slider 24 can slide in the receiving groove to extrude and form a cavity for casting, thereby realizing extrusion casting of the part.

[0069] In some embodiments, a heating device, such as a resistance rod, a high-frequency magnetic induction device, etc., is provided in the area corresponding to the transition part 11 on the lower mold 23 to perform local heating treatment on the transition part 11 so that the transition part 11 can be in a semi-solidified state.

[0070] Reference Figure 2 and Figure 3 As shown, the pouring system 25 is arranged at one end of the corresponding sub-cavity 21 away from the transition part 11, and the pouring system 25 includes a barrel 251 and a pouring channel 252 connected to the barrel 251, the pouring channel 252 is connected to the cavity, the barrel 251 is used for feeding, and the pouring channel 252 is arranged on one side of the sub-cavity 21 away from the transition part 11 to complete the filling of the entire sub-cavity 21 through the flow of molten metal.

[0071] For example, refer to Figure 2 As shown, a transition part 11 is arranged inside the cavity of the mold 2, and the cavity can be divided into two sub-cavities 21. Two pouring systems 25 are arranged accordingly. The two pouring systems 25 are distributed on both sides of the transition part 11 and are arranged away from the transition part 11. In this way, multi-end feeding of molten metal can be realized to increase filling efficiency.

[0072] After pouring is completed, refer to Figure 6 and Figure 7 As shown, the molten metal in the pouring channel 252 and part of the barrel 251 forms a pouring residue 15. After the sub-part 12 and the transition part 11 are demolded, the pouring residue 15 is removed by a cutting device, and then the weld seam 13 is reinforced and welded to complete the overall welding to form a final pouring part.

[0073] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0074] The above are only specific embodiments of the present disclosure, so that those skilled in the art can understand or implement the present disclosure. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure will not be limited to these embodiments herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for integrated extrusion casting and welding, characterized in that: The steps include: S1, determining a welding joint area of ​​a part to be cast, and manufacturing a transition part according to the shape of the part to be cast corresponding to the welding joint area; S2, placing the transition part in the mold, and dividing the mold cavity of the mold into a plurality of sub-cavities by the transition part; S3, filling the plurality of sub-cavities with molten metal and forming a plurality of sub-parts, wherein the sub-parts are melted and joined with the outer surface of the transition part to form a welded seam; S4, demoulding the sub-component and the transition part, and welding them along the weld seam.

2. The method for integrated extrusion casting and welding according to claim 1, characterized in that: The step S2 and the step S3 also include: preheating the mold as a whole; The area of ​​the mold corresponding to the transition part is locally heated, and / or the transition part is energized to heat the transition part to a semi-solidified state and keep the temperature.

3. The method for integrated extrusion casting and welding according to claim 1, characterized in that: The step S3 specifically includes: S31, filling the molten metal at one end of the sub-mold cavity away from the transition part, until the molten metal fills the entire sub-mold cavity in a direction toward the transition part.

4. The method for integrated extrusion casting and tailor-welding according to claim 3, characterized in that: The step S31 specifically includes: The piston of the squeeze casting equipment is set to fill the molten metal into the plurality of sub-cavities at a preset speed, wherein the preset speed of the piston is between 0.05 m / s and 4.0 m / s.

5. The method for integrated extrusion casting and tailor-welding according to claim 3, characterized in that: After step S31, the following steps are also included: S32. Before the molten metal solidifies, the pressure of the piston of the extrusion casting equipment is increased to a preset pressure and pressure-maintaining and shrinkage-compensating is performed, wherein the preset pressure of the piston is between 80 MPa and 300 MPa.

6. The method for integrated extrusion casting and tailor-welding according to claim 1, characterized in that: The step S3 specifically includes: The sub-component is formed by filling the mold with aluminum alloy liquid.

7. The method for integrated extrusion casting and tailor-welding according to claim 6, characterized in that: The step S1 specifically includes: S11, determining the welding joint area; S12, determining the shape of the transition part according to the welding joint area; S13, filling the mold with molten metal whose strength after filling is higher than that of the sub-part according to the determined shape to form the transition part.

8. A mold, characterized in that: The mold (2) is used to process the part to be cast (1) according to the squeeze casting and welding integrated molding method according to any one of claims 1 to 7; The mold (2) comprises an upper mold (22), a lower mold (23) and a plurality of extrusion sliders (24); the plurality of extrusion sliders (24) are arranged on the lower mold (23) and together form the mold cavity; the upper mold (22) is provided with a plurality of pouring systems (25); the plurality of pouring systems (25) are connected to the plurality of sub-mold cavities (21) in a one-to-one correspondence.

9. The mold according to claim 8, characterized in that: Heating devices are provided in areas on the upper mold (22) and the lower mold (23) corresponding to the transition part (11).

10. The mold according to claim 8, characterized in that: The pouring system (25) is arranged at an end of the corresponding sub-mold cavity (21) away from the transition part (11).

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