CN120926167A - Dissimilar material connection structure and method - Google Patents

Abstract

This invention provides a dissimilar material joining structure and method, relating to the field of materials processing technology. The dissimilar material joining structure includes: a casting with multiple pre-cast holes; an insert, one of which is disposed within each pre-cast hole, the insert including a connecting segment, which has a pre-installed state within the pre-cast hole and a separated state away from the pre-cast hole; and a connector, which is fitted to one side of the casting; wherein, when the connecting segment is in the pre-installed state, a portion of the connecting segment and the connector are connected by welding. Applying this solution achieves a high-strength, high-reliability connection between the casting and the connector, eliminating the need for specialized equipment, reducing overall production costs, simplifying the production process, significantly improving the connection efficiency between the connector and the casting, and shortening the production cycle.

Description

Dissimilar material connection structure and method

Technical Field

The invention relates to the technical field of material processing, in particular to a dissimilar material connecting structure and a dissimilar material connecting method.

Background

Along with the increasingly urgent pursuit of the automobile industry for light weight, the magnesium alloy is continuously expanded in application in the field of automobile manufacturing by virtue of the characteristics of low density and high specific strength, and the application range of castings is gradually extended from automotive body interior trim parts to structural parts. However, since magnesium alloy has a close-packed hexagonal crystal structure, the amount of slip that can be initiated at ordinary temperature is small, resulting in a limited plastic deformation capability. The characteristic is particularly prominent in the process of connecting dissimilar materials of steel and magnesium, and the cracking problem of the connecting part is extremely easy to cause.

In the prior art, a mature and reliable steel-magnesium connection process has not been developed, and becomes a key bottleneck for restricting the large-scale application of magnesium alloy in automobile structural parts.

In view of the above technical problems, no effective solution has been proposed at present.

Disclosure of Invention

The invention mainly aims to provide a dissimilar material connecting structure and a dissimilar material connecting method, which are used for solving the problem of poor steel-magnesium connecting effect in the prior art.

In order to achieve the above purpose, according to one aspect of the invention, a dissimilar material connection structure is provided, which comprises a casting, a plurality of precast holes are formed in the casting, an insert is arranged in each precast hole, the insert comprises a connection section, the connection section is in a preassembled state in the precast hole, the connection section is in a separated state far away from the precast hole, the connection section is attached to one side of the casting, and when the connection section is in the preassembled state, part of the connection section is connected with the connection section through welding.

Further, the connector is disposed the same as the insert material and the casting is disposed different from the insert material.

Further, the casting is made of magnesium alloy.

Further, the material of the connecting piece is low carbon steel.

Further, the linkage segment is one side open-ended barrel structure, and the inserts still is including connecting the turn-ups, and the circumference of connecting the opening side of turning over the edge linkage segment outwards extends the setting, and wherein, the bottom and the linkage piece welded connection of linkage segment connect the turn-ups overlap joint in the surface of foundry goods.

Further, the outer side wall of the connecting section is connected with the hole wall of the precast hole, a hollow area enclosed between the inner side walls of the connecting section forms an operation space, and the operation space is used for connecting the connecting section and the connecting piece.

Further, the insert is connected with the pre-cast hole on the casting through interference fit.

Further, the connecting piece is connected with the bottom of the connecting section through spot welding.

According to another aspect of the invention, a method for connecting dissimilar materials is provided, and comprises the steps of forming a plurality of precast holes on a casting, wherein the casting is made of magnesium alloy, selecting an insert matched with the depth of the precast holes, aligning the insert to the precast holes, pressing the insert into each precast hole through a pressing head to enable the casting and the insert to form an integrated structure, and welding the insert and a connecting piece, wherein the connecting piece and the insert are made of low carbon steel.

The method comprises the steps of enabling the connecting piece to be in contact with the end of one electrode cap, enabling the insert to be in contact with the end of the other electrode cap, and carrying out spot welding on the connecting piece and the insert through the two electrode caps, wherein the welding current of spot welding is I, the welding time of spot welding is t, the welding pressure of spot welding is F, I is more than or equal to 6.5KA and less than or equal to 7.5KA, t is more than or equal to 240ms and less than or equal to 260ms, and F is more than or equal to 2400N and less than or equal to 2600N.

Optionally, the method further comprises the step of detecting welding parameter information of the joint of the insert and the connecting piece after the spot welding of the insert and the connecting piece is completed, wherein the welding parameter information at least comprises shearing force, stretching force and welding core diameter, and the completion of welding is confirmed under the condition that the shearing force is more than or equal to 7KN, the stretching force is more than or equal to 2.1KN and the welding core diameter is more than or equal to 4.3 mm.

By applying the technical scheme of the invention, the regular pre-cast holes are formed in the casting, the inserts are arranged to be of a structure matched with the pre-cast holes, the connecting sections of the inserts extend into the pre-cast holes until the connecting sections are in contact connection with the connecting pieces attached to the other ends of the casting, the connecting sections are in a preassembled state, the inserts and the casting form an integrated structure, and then the inserts and the connecting pieces are welded and connected, so that the high-strength and high-reliability connection of the casting and the connecting pieces can be realized, special equipment is not needed, the overall production cost can be reduced, the production flow is simplified, the connecting efficiency of the connecting pieces and the casting is greatly improved, and the production period is shortened.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings:

fig. 1 shows a schematic structural view of a first embodiment of a dissimilar material connection structure according to the present invention;

fig. 2 shows a schematic structural view of a second embodiment of a dissimilar material connection structure according to the present invention;

FIG. 3 shows an enlarged schematic view at A in FIG. 2;

Fig. 4 shows a schematic structural view of a third embodiment of a dissimilar material connection structure according to the present invention;

fig. 5 shows a schematic structural view of a fourth embodiment of a dissimilar material connection structure according to the present invention;

fig. 6 shows a flow chart of an embodiment of a dissimilar material connection method according to the present invention.

Wherein the above figures include the following reference numerals:

10. 101, casting, pre-casting holes;

20. insert 200, operation space 21, connection section 22, connection flange;

30. a connecting piece;

40. an electrode cap.

Detailed Description

It should be noted that, without conflict, the embodiments of the present application and features of the embodiments may be combined with each other. The application will be described in detail below with reference to the drawings in connection with embodiments.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the present application. As used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.

It should be noted that the terms "first," "second," and the like in the description and the claims of the present application and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

Exemplary embodiments according to the present application will now be described in more detail with reference to the accompanying drawings. These exemplary embodiments may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. It should be understood that these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of these exemplary embodiments to those skilled in the art, that in the drawings, it is possible to enlarge the thicknesses of layers and regions for clarity, and that identical reference numerals are used to designate identical devices, and thus descriptions thereof will be omitted.

Referring to fig. 1 to 5, a dissimilar material connection structure is provided according to an embodiment of the present application.

Specifically, as shown in fig. 1 to 3 and 5, the dissimilar material connection structure comprises a casting 10, an insert 20 and a connecting piece 30, wherein a plurality of precast holes 101 are formed in the casting 10, one insert 20 is arranged in each precast hole 101, the insert 20 comprises a connecting section 21, the connecting section 21 is in a preassembled state in the precast hole 101, the connecting section 21 is in a separated state far away from the precast hole 101, the connecting piece 30 is attached to one side of the casting 10, and when the connecting section 21 is in the preassembled state, part of the connecting section 21 is connected with the connecting piece 30 through welding.

By means of the technical scheme, the insert 20 is arranged to be of a structure matched with the precast hole 101 through the fact that the regular precast hole 101 is formed in the casting 10, the connecting section 21 of the insert 20 extends into the precast hole 101 until the connecting section 21 is in contact connection with the connecting piece 30 attached to the other end of the casting 10, the connecting section 21 is in a preassembled state, the insert 20 and the casting 10 form an integrated structure, then the insert 20 and the connecting piece 30 are welded and connected, high-strength and high-reliability connection of the casting 10 and the connecting piece 30 can be achieved, special equipment is not needed, overall production cost can be reduced, production flow is simplified, connecting efficiency of the connecting piece 30 and the casting 10 is greatly improved, and production period is shortened.

It should be noted that, the positions and the number of the pre-cast holes 101 may be specifically determined according to the installation environments of the castings 10 and the connectors 30, the pre-cast holes 101 are disposed along the thickness direction of the castings 10 so as to penetrate through the castings 10, and when the connecting sections 21 of the insert 20 extend into the pre-cast holes 101 and penetrate out of the pre-cast holes 101 to contact with the connectors 30, the connecting sections 21 are in a pre-assembled state, and at this time, the connecting sections 21 contact with the connectors 30, and the connecting sections 21 and the connectors 30 can be welded together to form an integral structure so as to tightly attach and connect the castings 10 and the connectors 30 together.

Specifically, the connector 30 is disposed the same as the insert 20 material and the casting 10 is disposed different from the insert 20 material. By setting the connecting piece 30 and the insert 20 to be the same material, the thermal expansion coefficient matching in the welding process can be ensured, the welding stress is reduced, the connection stability is improved, the thermal stress concentration at the connecting part is reduced, the service life of the connecting structure is prolonged, and the casting 10 and the insert 20 are set to be different materials, so that the high-strength connection of different materials can be realized, the advantages of specific strength, weight, hardness and the like of different materials can be further realized, and the reliability and the stability of the connection are improved.

It should be noted that, because the connection between the different materials of the connecting piece 30 and the casting 10 has a large difference in melting point, thermal expansion coefficient, conductivity and other factors, and the direct welding cannot be performed, by introducing the insert 20, by selecting the same material as the connecting piece 30 for the insert 20, adverse effects caused by these factors, such as cracks caused by thermal stress and welding problems caused by overlarge contact resistance, can be effectively avoided, and then the stable high-strength connection between the connecting piece 30 and the casting 10 is realized by the cooperation connection between the insert 20 and the casting 10.

In a preferred embodiment of the present application, the material of the casting 10 is magnesium alloy and the material of the connector 30 is mild steel. Magnesium alloy is widely used in the field of automobile manufacturing due to the characteristics of light weight and high specific strength, particularly in application scenes of pursuing light weight design, and low carbon steel is used as a common engineering material and has good weldability, plasticity and toughness. The low carbon steel can provide a stable connection base for the magnesium alloy castings, and the magnesium alloy and the low carbon steel can be firmly connected together through the connection structure in the above embodiment.

In the embodiment, the low-carbon steel is relatively low in cost and easy to process and obtain, and can be used as a connecting piece, so that the overall manufacturing cost can be reduced, more expensive materials which possibly affect the environment can be avoided, and the strength and reliability of the low-carbon steel can effectively compensate the potential weakness of the magnesium alloy at the connecting part, particularly in view of the limitation of the magnesium alloy in terms of plastic deformation. By embedding the mild steel connection 30 into the magnesium alloy casting 10, the mechanical properties of the connection region may be significantly enhanced, making it more robust when subjected to loads or stresses. Through the material combination of the magnesium alloy casting and the low-carbon steel connecting piece, the performance and the cost of the connecting part are ensured while the light weight requirement of the automobile is met.

The connecting structure in this embodiment may be mainly applied to vehicle structures, such as frames, bodywork panels, automobile chassis, door hinges, various structural members that need to be connected with steel materials, such as integrated rear floors, integrated front cabins, etc., the magnesium alloy may effectively reduce the dead weight of the vehicle, promote the dynamic performance and the operability of the vehicle, and the low carbon steel as the material of the connecting member 30 may ensure the safety and the reliability of the connection.

Further, as shown in fig. 3, the connecting section 21 is a barrel-shaped structure with an opening at one side, the insert 20 further comprises a connecting flange 22, the connecting flange 22 extends outwards along the circumference of the opening side of the connecting section 21, wherein the bottom of the connecting section 21 is welded with the connecting piece 30, and the connecting flange 22 is lapped on the surface of the casting 10. The connecting section 21 is designed into a barrel-shaped structure with one side open, a closed space is formed around the connecting piece 30, thereby providing additional support and protection for the connecting piece 30 in the welding process, increasing the contact area of the connecting point, enabling the welding operation to uniformly distribute heat in a larger range, helping to form a firmer welding core, simultaneously, the bottom of the connecting section 21 and the connecting piece 30 are directly welded, ensuring the tight combination between the two to form a firm connecting base, and the connecting flange 22 extends outwards along the peripheral direction from the opening side of the connecting section 21 along the opening edge of the connecting section 21, increasing the contact area between the insert 20 and the surface of the casting 10, providing better mechanical engagement effect between the connecting flange 22 and the surface of the casting 10, forming physical anchoring, keeping the connection stable even under the action of external force, and covering the uneven area possibly existing between the connecting section 21 and the casting 10, and improving the aesthetic property and the sealing property of the connecting position.

In this embodiment, by utilizing the lap joint effect of the connection flange 22 and the surface of the casting 10, a composite connection structure is formed together, the connection area is increased, the connection strength of the casting 10 and the insert 20 is improved, the shearing force and the tensile force of the connection point are obviously enhanced, the overall bearing capacity of the connection structure is improved, the stability of the connection point can be maintained even if the connection structure is subjected to complex working conditions such as vibration and impact in the running process of a vehicle, and the potential safety hazard caused by connection failure is effectively avoided.

Further, as shown in fig. 4, the outer side wall of the connecting section 21 is connected with the wall of the precast hole 101, and a hollow area enclosed between the inner side walls of the connecting section 21 forms an operation space 200, and the operation space 200 is used for connecting the connecting section 21 and the connecting piece 30. The operation space 200 provides enough space for the welding process, is convenient for the operation of welding equipment, and simultaneously provides a margin for the adjustment of welding parameters, so that the flexibility and controllability of the welding process are enhanced, and the welding quality and the production efficiency are improved.

In one embodiment of the present application, as shown in fig. 1, the welding apparatus at least includes an electrode cap 40, the electrode cap 40 is a pointed electrode cap, and the end of the electrode cap may extend into the operation space 200 to perform a welding operation on the bottom end of the connection section 21.

Preferably, the insert 20 is connected to the pre-cast hole 101 in the casting 10 by an interference fit. The size of the insert 20 is set to be slightly larger than the outer diameter of the precast hole 101, the insert 20 is provided with pressure by an external instrument or a pressure head, when the insert 20 is pressed into the precast hole 101, extrusion can be generated between the insert 20 and the hole wall of the precast hole 101, a mechanical locking effect is formed, and the insert 20 and the casting 10 are tightly attached by adopting the elastic deformation characteristic of an interference fit available material, so that the connecting effect with high strength and high stability is realized.

It should be noted that, the insert 20 and the pre-cast hole 101 are in interference fit, and the friction resistance of the connecting surface is increased through the physical locking effect, so that the bonding strength of the connecting section 21 and the casting 10 is remarkably improved; at the same time, the interference fit may reduce the time and cost required for assembly, while avoiding the use of additional fasteners and reducing material costs and overall weight, as compared to other methods of bolting, etc.

In one embodiment of the application, the connector 30 is connected to the bottom of the connecting section 21 by spot welding. The diameter of the precast hole 101 is phi 12-14mm, and the size of a round hole is smaller, so that the tip of the tip electrode cap can be extended into the operation space 200 to be welded, and the connecting piece 30 and the two ends of the connecting section 21 are bonded by adopting a pressurizing spot welding mode, and the metal of the connecting piece 30 and the connecting section 21 is melted at the instant high temperature to form a welding core, so that the solid connection between metals is realized, the connection speed is high, the welding strength is high, and the welding device is suitable for automatic batch production.

It should be noted that, compared with the conventional common mechanical connection modes such as screw connection and willow connection, the conventional mode of the screw connection or the willow connection requires material-to-material interlocking, and the use of the willow butyl or the screw cannot realize the light weight of the product, the scheme of spot welding by using the insert and the connecting piece in the embodiment can realize the connection mode of magnesium under steel or on magnesium under steel without additionally adding a connecting element, so that the quality of the link is ensured, and the cost is reduced.

According to another embodiment of the present application, there is also provided a dissimilar material connection method, as shown in fig. 6, comprising the steps of:

step S1, a plurality of pre-cast holes are formed in a casting, wherein the casting is made of magnesium alloy;

Specifically, the magnesium alloy casting is provided with the pre-cast hole, so that the subsequent installation of the insert is facilitated, the casting and the other part are firmly connected, an anchor point is provided for a connecting structure by the existence of the pre-cast hole, the accurate positioning of the connecting piece is ensured, and the connecting piece and the casting form high-strength connection through subsequent spot welding and other connecting processes.

It should be noted that, the number and the position of the pre-cast holes can be set or adjusted according to the connection requirement and the structural characteristics of the castings, and when the pre-cast holes are set, the sufficient safety distance between the holes is ensured according to the mechanical properties of the castings, so that crack expansion caused by stress concentration at the edge of the holes is prevented, and meanwhile, the overall structural strength and the rigidity of the castings are also required to be considered, so that the bearing capacity of the castings is prevented from being weakened due to excessive distribution of the holes.

S2, selecting an insert matched with the depth of the precast hole;

in particular, the depth of the insert should be matched to the depth of the pre-cast hole to ensure that the insert is fully pressed into the pre-cast hole so that the insert passes through the pre-cast hole to contact the connector at the other end of the casting. By pre-fabricating and selecting inserts that match the number of pre-cast hole sizes, the tuning and preparation effort is reduced, thereby improving the efficiency of the overall production process.

S3, aligning the inserts to the pre-cast holes, applying pressure to the inserts through a pressure head, and pressing the inserts into the pre-cast holes so as to form an integrated structure of the casting and the inserts;

Specifically, even pressure is applied to the insert by using a pressure head or other press-fitting tools, so that the deformation of the insert or the damage to the casting caused by uneven local stress is avoided, and the deformation of the insert is avoided.

It should be noted that, the size of the insert can be set to be slightly larger than the size of the precast hole, when the insert is pressed by using a pressing head or other pressing tools, the insert and the precast hole can be connected through interference fit, and the casting material can slightly deform around the insert, so that the insert and the casting are tightly combined to form an integrated structure, the integrated structure not only can remarkably improve the physical strength of connection, but also can enhance the tensile and shearing resistance of the connection part, can bear larger load, and avoid looseness between the insert and the casting in the later use process.

And S4, welding the insert and the connecting piece, wherein the connecting piece and the insert are made of low carbon steel.

Specifically, the materials of the connecting piece and the insert are selected to be the same material, namely low carbon steel, the connecting piece and the insert are connected by welding, the welding is fast in speed and low in cost, the automation is easy, a welding core formed by welding can provide a high-strength linking effect, and meanwhile, the thickness and linking requirements of different connecting pieces can be met by adjusting welding parameters, and good process adaptability and flexibility are shown.

The method comprises the steps of forming a plurality of precast holes on a casting, wherein the casting is made of magnesium alloy, selecting an insert matched with the depth of the precast holes, aligning the insert to the precast holes, applying pressure to the insert through a pressure head, pressing the insert into each precast hole so as to form an integral structure with the casting, and welding the insert and a connecting piece, wherein the connecting piece and the insert are made of low carbon steel. And by combining the pre-cast hole, interference fit and welding technology, the high-efficiency connection of the magnesium alloy casting and the low-carbon steel connecting piece is realized, the connection process is simple and quick, the connection strength and reliability are high, and the method is suitable for mass production.

Optionally, the insert is welded to the connector, the method comprising:

step S41, contacting the connecting piece with the end of one electrode cap, and contacting the insert with the end of the other electrode cap;

Specifically, the electrode caps can adopt pointed electrode caps, and simultaneously spot-welding two ends of the connecting piece, which are contacted with the insert, a closed loop is formed between the two electrode caps, the electric welding machine generates high temperature through current pulse and the contact point of the electric welding machine, so that a welding core is formed at the contact part of the connecting piece and the insert. The double-electrode contact mode accelerates the welding process, reduces the welding time, and the welding core formed in the welding process can obviously strengthen the binding force between the connecting piece and the insert, and improves the stability and the reliability of connection.

And S42, performing spot welding on the connecting piece and the insert through the two electrode caps, wherein the welding current of the spot welding is I, the welding time of the spot welding is t, the welding pressure of the spot welding is F, I is more than or equal to 6.5KA and less than or equal to 7.5KA, t is more than or equal to 240ms and less than or equal to 260ms, and F is more than or equal to 2400N.

Specifically, the higher current is favorable for quickly heating the material to a molten state, so that a weld core between the connecting piece and the insert is formed, the conductivity and the thickness of the material are required to be considered for the selection of the current to ensure that the weld core with enough strength is formed, the selection of the welding time is required to ensure that the current is applied to the material for reaching the molten state, the situation that the material is overheated due to overlong time to cause the change of the material property or the occurrence of welding defects such as cracks or uneven welding spots can be avoided, and the application of proper pressure is favorable for keeping the connecting piece and the insert stably contacted in the welding process, and also favorable for forming the weld core and forming in the cooling process after welding, so that the strength and the stability of the connecting part are ensured.

Preferably, welding current I is 7KA, welding time is 250ms, welding pressure is 2500N, heat and pressure generated in the welding process can be accurately controlled by setting welding current, time and pressure to the above parameters, the formation quality of welding cores is ensured, and meanwhile, the welding efficiency can be remarkably improved by rapid welding time and stable welding current, and production cost is reduced.

Through the steps S41-S42, the optimal welding conditions are found by adjusting the current, time and pressure, so that the high-quality welding effect is realized, the quality of the welding point is stable, and the connection strength meets the design requirement.

Optionally, the method further comprises:

S5, after the spot welding of the insert and the connecting piece is completed, detecting welding parameter information of the connecting part of the insert and the connecting piece, wherein the welding parameter information at least comprises shearing force, stretching force and welding core diameter;

Specifically, the weld is subjected to a shear test by standard shear test equipment, evaluating the performance of the weld when subjected to shear loads, the shear test being able to verify the ability of the weld to resist external forces parallel to the surface of the weld core, ensuring the reliability of the connection when subjected to transverse loads. And (3) using a tension tester to carry out a tensile force test on the welding points, evaluating the tensile force of the welding points along the axis direction of the welding cores, and the tensile force test can check the stability of the welding points when bearing longitudinal loads, so that the connecting piece is ensured not to be loosened or broken from the casting when bearing the tensile force. Measuring the nugget diameter is typically done by visual inspection or using a measuring tool, ensuring that the nugget diameter is within the expected range, too small a nugget diameter may mean incomplete welding and insufficient connection strength, while too large a nugget diameter may result in excessive melting or deformation of the material surrounding the weld spot, affecting the aesthetics and functionality of the connection.

It should be noted that, nondestructive detection methods such as ultrasonic detection, magnetic powder detection or eddy current detection can be adopted to perform preliminary inspection on the welded joint to evaluate the surface quality and internal defects, and for the critical parts or the case of needing to verify the welding strength, destructive detection methods such as drawing test, shearing test and the like can be selected to directly apply force to the welded joint, and data such as shearing force, stretching force and the like can be obtained through the test.

And S6, when the shearing force is more than or equal to 7KN, the tensile force is more than or equal to 2.1KN and the diameter of the welding core is more than or equal to 4.3mm, confirming that the welding is completed.

Specifically, the welding spot needs to be capable of bearing a transverse force of at least 7 kilonewtons without breaking and bearing a longitudinal tensile force of at least 2.1 kilonewtons, so that the connection strength and stability of the connecting piece when bearing an axial load are ensured, and a larger welding core diameter means that the welding spot has a larger contact area, and can provide a stronger connection force and better durability.

Through step S5-step S6, detection standards of shearing force, tensile force and nugget diameter are set and are strictly followed, high-quality welding is guaranteed between the connecting piece and the insert, the connecting strength reaches a preset standard, the performance of the connecting structure is verified, the reliability and the safety of connection are guaranteed, and further high requirements of the industrial fields such as automobile manufacturing and the like on the connecting strength and the stability are met.

The application also provides a preferred embodiment of the dissimilar material connection method, in the preferred embodiment, a 4.4mm thick high-pressure magnesium alloy casting and a 1.5mm ST280 steel plate are adopted for connection, casting hole precasting is firstly carried out to lay a foundation for subsequent connection, then an insert is designed and manufactured to ensure the matching connection requirement, then the insert is pressed into the precasted hole to realize preliminary fixation, and finally the magnesium alloy casting and steel are firmly connected through spot welding, wherein the specific steps are as follows:

Firstly, pre-opening pre-cast holes phi 12 in a casting, wherein the hole spacing is 40mm, and 24 holes are formed in total;

Embedding an insert with the designed inner diameter of phi 10, the wall thickness of 1mm, the outer diameter of the connecting section of phi 16 and the depth of 4.4mm on the pre-cast hole, wherein the insert is made of low-carbon steel;

Thirdly, welding the casting with the embedded insert with a 1.5mm S280 steel plate, selecting a pointed electrode cap with the diameter phi of phi 13 mm or 20mm and the end diameter phi of 6 as an electrode cap, and performing spot welding on the insert and the steel plate, wherein the welding pressure is 2500N, the welding time is 252ms, and the welding current is 7KA;

Step four, cutting and performance detection are carried out on the welded joint after welding is completed, and performance detection is carried out on the joint obtained in the embodiment, so that the shearing force of the joint is 7.97KN, the tensile force is 2.31KN, and the diameter of a welding core is 6.04mm;

and fifthly, repeating welding according to the welding parameters until the welding is completed.

Through the description, the dissimilar material connection method in the embodiment has the advantages that the method breaks through the limitation of the traditional connection technology, a special process is designed aiming at the characteristics of two materials, high-strength and high-reliability connection is achieved, an entire vehicle factory does not need to purchase expensive special equipment, the equipment input cost is effectively reduced, meanwhile, the production flow is simplified, the connection efficiency is greatly improved, the production period is shortened, the material waste and the energy consumption are reduced, the production cost is obviously reduced, and an economic and efficient solution is provided for the lightweight manufacturing of automobiles through optimizing the process parameters.

Spatially relative terms, such as "above," "upper" and "upper surface," "above" and the like, may be used herein for ease of description to describe one device or feature's spatial relationship to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "above" or "over" other devices or structures would then be oriented "below" or "beneath" the other devices or structures. Thus, the process is carried out, the exemplary term "above" may be included. Upper and lower. Two orientations below. The device may also be positioned in other different ways (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

In addition to the foregoing, references in the specification to "one embodiment," "another embodiment," "an embodiment," etc., indicate that the particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the application, as generally described. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is intended that such feature, structure, or characteristic be implemented within the scope of the application.

In the foregoing embodiments, the descriptions of the embodiments are emphasized, and for parts of one embodiment that are not described in detail, reference may be made to related descriptions of other embodiments.

The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (11)

1. A dissimilar material connection structure, characterized in that it comprises: A casting (10) having a plurality of pre-cast holes (101) provided thereon; Insert (20), each of the pre-cast holes (101) is provided with one insert (20), the insert (20) includes a connecting section (21), the connecting section (21) has a pre-installed state located in the pre-cast hole (101), and the connecting section (21) has a separated state away from the pre-cast hole (101); A connector (30) is fitted to one side of the casting (10); When the connecting segment (21) is in the pre-installed state, part of the connecting segment (21) is connected to the connector (30) by welding. 2. The dissimilar material connection structure according to claim 1, characterized in that the connector (30) and the insert (20) are made of the same material, and the casting (10) and the insert (20) are made of different materials. 3. The dissimilar material connection structure according to claim 2, wherein the material of the casting (10) is a magnesium alloy. 4. The dissimilar material connection structure according to claim 2, wherein the material of the connector (30) is low carbon steel. 5. The dissimilar material connection structure according to any one of claims 1-4, characterized in that the connecting segment (21) is a barrel-shaped structure with an opening on one side, the insert (20) further includes a connecting flange (22), the connecting flange (22) extends outward in the circumferential direction along the opening side of the connecting segment (21), wherein the bottom of the connecting segment (21) is welded to the connector (30), and the connecting flange (22) overlaps the surface of the casting (10). 6. The dissimilar material connection structure according to any one of claims 1-4, characterized in that the outer wall of the connecting segment (21) is connected to the hole wall of the pre-cast hole (101), and the hollow area enclosed between the inner walls of the connecting segment (21) forms an operating space (200), the operating space (200) being used for connecting the connecting segment (21) and the connector (30). 7. The dissimilar material connection structure according to claim 6, characterized in that the insert (20) and the pre-cast hole (101) on the casting (10) are connected by an interference fit. 8. The dissimilar material connection structure according to claim 6, characterized in that the connector (30) and the bottom of the connecting segment (21) are connected by spot welding. 9. A method for joining dissimilar materials, characterized in that the method comprises: Multiple pre-cast holes are opened on the casting, wherein the material of the casting is a magnesium alloy; Select an insert that matches the depth of the pre-cast hole; Align the insert with the pre-cast hole, apply pressure to the insert with a pressure head, and press the insert into each of the pre-cast holes so that the casting and the insert form an integral structure; The insert and the connector are welded together, wherein the materials of the connector and the insert are low-carbon steel. 10. The method for joining dissimilar materials according to claim 9, characterized in that the insert and the connector are welded together, the method comprising: The connector is brought into contact with the end of one electrode cap, and the insert is brought into contact with the end of the other electrode cap; The connector and the insert are spot welded using two electrode caps, wherein the welding current is I, the welding time is t, the welding pressure is F, 6.5KA≤I≤7.5KA, 240ms≤t≤260ms, and 2400N≤F≤2600N. 11. The method for joining dissimilar materials according to claim 9, characterized in that the method further comprises: After the insert and the connector are spot welded, the welding parameter information at the connection between the insert and the connector is detected. The welding parameter information includes at least shear force, tensile force, and weld nugget diameter. Welding is confirmed to be complete when the shear force is ≥7KN, the tensile force is ≥2.1KN, and the weld nugget diameter is ≥4.3mm.