CN115156681A

CN115156681A - Resistance spot welding method for multilayer board

Info

Publication number: CN115156681A
Application number: CN202210831278.8A
Authority: CN
Inventors: 张永强; 朱国森; 王松涛; 李学涛; 付参; 王鹏博; 鞠建斌; 余洋; 陈炜煊; 伊日贵
Original assignee: Shougang Group Co Ltd
Current assignee: Shougang Group Co Ltd
Priority date: 2022-07-14
Filing date: 2022-07-14
Publication date: 2022-10-11

Abstract

The application relates to the technical field of resistance spot welding and discloses a resistance spot welding method of a multilayer board. The multilayer board comprises a first test board, a middle test board and a second test board, and the resistance spot welding method comprises the following steps: preparing supporting feet around the position to be welded on the second test plate; stacking the first test plate, the middle test plate and the second test plate in sequence; the supporting legs are arranged between the second test plate and the middle test plate and used for forming a prefabricated gap between the second test plate and the middle test plate; and controlling an upper electrode of the spot welding machine to press the upper welding position of the second test plate, and controlling a lower electrode of the spot welding machine to press the lower welding position of the first test plate for welding. The method promotes the nucleation of the outer side thin plate and the low-resistivity material in the welding combination, and avoids the welding defects such as desoldering, splashing and the like.

Description

Resistance spot welding method for multilayer board

Technical Field

The application relates to the technical field of resistance spot welding, in particular to a resistance spot welding method of a multilayer board.

Background

Resistance spot welding is a pressure welding method. In general, a fusion welding method is a method in which an electric current is passed through a weld plate group under the pressure of an electrode, the joint portion of the weld plate group is melted by joule heat, and the joint is formed by a nugget after cooling.

Resistance spot welding is widely applied to industries such as automobiles, household appliances, machinery and the like. In practical engineering applications, there is a need for resistance spot welding of multilayer boards. When the thickness of the test plate at the outermost layer is thin and the resistivity is relatively low, the interface between the test plate and the adjacent test plate in the welded plate group is difficult to nucleate. When the welding current is small, cold welding is easy to occur; when the welding current is larger, other interfaces in the welding plate group are easy to generate serious splashing due to overlarge growth of a weld nugget, so that the welding quality is influenced.

Disclosure of Invention

The application aims to provide a resistance spot welding method of a multilayer board, which promotes nucleation of an outer thin board and a low-resistivity material in a welding combination and avoids welding defects such as desoldering and splashing.

Other features and advantages of the present application will be apparent from the following detailed description, or may be learned by practice of the application.

According to an aspect of an embodiment of the present application, there is provided a resistance spot welding method of a multi-layer board including a first test panel, a middle test panel, and a second test panel, the resistance spot welding method including: preparing supporting legs around the upper welding position of the second test plate; stacking the first test plate, the middle test plate and the second test plate in sequence, wherein the supporting legs are arranged between the second test plate and the middle test plate to form a prefabricated gap between the second test plate and the middle test plate; and controlling an upper electrode of the spot welding machine to press the upper welding position of the second test plate, and controlling a lower electrode of the spot welding machine to press the lower welding position of the first test plate for welding.

In some embodiments, controlling the upper electrode of the spot welder to press against the upper welding position of the second test plate and controlling the lower electrode of the spot welder to press against the lower welding position of the first test plate to weld includes: the upper electrode and the lower electrode tightly press the multilayer board, so that the prefabricated gap between the upper welding position and the middle test board is reduced to 0; controlling the upper electrode and the lower electrode to be electrified to enable the upper welding position and the lower welding position to generate heat; and maintaining the pressure of the upper electrode and the lower electrode until the welding is completed.

In some embodiments, said controlling the upper and lower electrodes to be energized to cause the upper and lower weld locations to generate heat comprises: preheating the upper welding position and the lower welding position by introducing preheating current I1; and welding between the upper welding position and the lower welding position by applying a welding current I2.

In some embodiments, the preheating current I1 is related to the welding current I2 by: i2 is more than 1.5I1.

In some embodiments, the preheating current I1 and the welding current I2 have a preparation time C therebetween, the preparation time C satisfying: c is more than or equal to 20ms.

In some embodiments, the first test board has a thickness h1 and a resistivity ρ 1, and the second test board has a thickness h2 and a resistivity ρ 2, wherein h2 > h1 and ρ 2 > ρ 1.

In some embodiments, the intermediate panel comprises at least one intermediate panel.

In some embodiments, the support foot is at a distance L from the upper weld location, where L satisfies: l is more than or equal to 10 mm and less than or equal to 30mm.

In some embodiments, the support foot has a height H, which satisfies: h is more than or equal to 0.1mm and less than 1mm.

In some embodiments, the shape of the support feet includes cylindrical, prismatic, conical, and pyramidal.

By the technical scheme of this application more than, compare with prior art, its beneficial effect that is showing lies in: through set up the supporting legs at the second test panel, realize the reposition of redundant personnel between second test panel and middle test panel in welding process to avoid taking place to splash between second test panel and the middle test panel, and promote the nucleation between first test panel and the middle test panel. The shape, the number and the distance between the support legs and the welding position obviously influence the size of the shunt current. On the one hand, the smaller the distance between the supporting leg and the welding position is, the larger the welding shunt is, and the more obvious the effect is. On the other hand, through tests, the distance between the supporting leg and the welding position satisfies that L is more than or equal to 10 mm and less than or equal to 30mm, and the welding effect is best.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.

Drawings

The above and other features and advantages of the present application will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings.

FIG. 1 shows a flow diagram according to an embodiment of the present application;

FIG. 2 shows a schematic diagram of a multi-layer board structure according to one embodiment of the present application;

FIG. 3 shows a schematic view of a completed structure for multi-layer board welding according to one embodiment of the present application;

fig. 4 shows a schematic diagram of a prior art multi-layer board soldering completion.

The reference numerals are explained below: 1. a first test panel; 2. intermediate test plates; 3. a second test panel; 4. supporting legs; 5. prefabricating a gap; 6. an upper electrode; 7. an upper welding position; 8. a lower electrode; 9. a lower welding position; 10. and (5) welding a core.

Detailed Description

Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments may, however, be embodied in many different forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art.

Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the application. One skilled in the relevant art will recognize, however, that the subject matter of the present application can be practiced without one or more of the specific details, or with other methods, components, devices, steps, and so forth. In other instances, well-known methods, devices, implementations, or operations have not been shown or described in detail to avoid obscuring aspects of the application.

The block diagrams shown in the figures are functional entities only and do not necessarily correspond to physically separate entities. I.e. these functional entities may be implemented in the form of software, or in one or more hardware modules or integrated circuits, or in different networks and/or processor means and/or microcontroller means.

The flow charts shown in the drawings are merely illustrative and do not necessarily include all of the contents and operations/steps, nor do they necessarily have to be performed in the order described. For example, some operations/steps may be decomposed, and some operations/steps may be combined or partially combined, so that the actual execution sequence may be changed according to the actual situation.

According to some embodiments, as shown in fig. 1 to 2, the present application provides a resistance spot welding method of a multi-layer board including a first test board 1, an intermediate test board 2, and a second test board 3, the resistance spot welding method including: 101, preparing supporting legs 4 around an upper welding position 7 of the second test plate 3; 102, stacking the first test plate 1, the middle test plate 2 and the second test plate 3 in sequence, wherein the supporting legs 4 are arranged between the second test plate 3 and the middle test plate 2 to form a prefabricated gap 5 between the second test plate 3 and the middle test plate 2; and 103, controlling an upper electrode 6 of the spot welding machine to press an upper welding position 7 of the second test plate 3, and controlling a lower electrode 8 of the spot welding machine to press a lower welding position 9 of the first test plate 1 for welding.

Based on the above embodiments, in step 101, the number of the supporting legs 4 may be one or more than two, and in some embodiments, the supporting legs 4 are disposed around the upper welding position of the second test board 3, one on one side, and the number is two in total. The height of the supporting legs 4 is H, and the H needs to meet the following requirements: h < 1mm is 0.1mm ≦ H, and in some embodiments, the height H of support foot 4 is set to 0.2mm. The distance of welding position 7 is L on the supporting legs 4 distance, and L needs to satisfy: l is 10 ≦ L ≦ 30mm, in some embodiments, the support leg 4 is at a distance L =20mm from the upper welding position 7, the support leg 4 may have a cylindrical, prismatic, conical, pyramidal shape, and the like shape, and in some embodiments, the support leg 4 is configured in a cylindrical shape.

In step 102, the first test plate 1, the intermediate test plate 2 and the second test plate 3 are sequentially stacked together, and the supporting legs 4 are disposed between the second test plate 3 and the intermediate test plate 2, so as to form a prefabricated gap 5 between the second test plate 3 and the intermediate test plate 2, thereby facilitating spot welding. Wherein, the middle test board 2 comprises at least one middle board which is overlapped. For more convenient understanding, the test panel formed by stacking a plurality of intermediate panels is represented by one intermediate panel 2, but the intermediate panel 2 may represent more than one intermediate panel stacked.

In step 103, the upper electrode 6 of the spot welder is controlled to press against the upper welding position 7 of the second test plate 3, and the lower electrode 8 of the spot welder is controlled to press against the lower welding position 9 of the first test plate 1 for welding. Wherein, the upper electrode 6 and the lower electrode 8 are aligned up and down on the same vertical line.

According to some embodiments, controlling the upper electrode 6 of the spot welder to press against the upper welding position 7 of the second test plate 3 and controlling the lower electrode 8 of the spot welder to press against the lower welding position 9 of the first test plate 1 for welding comprises: the upper electrode 6 and the lower electrode 8 tightly press the multilayer board, so that the prefabricated gap 5 between the upper welding position 7 and the middle test board 2 is reduced to 0; controlling the upper electrode 6 and the lower electrode 8 to be electrified so as to enable the upper welding position 7 and the lower welding position 9 to generate heat; the pressure of the upper electrode 6 and the lower electrode 8 is maintained until the welding is completed.

Based on the above embodiment, the medium frequency resistance spot welder DB220 by OBARA was used. The pressure F =4kN of the upper electrode 6 and the lower electrode 8 is reduced by the pressure from 0.2mm to 0mm in the upper welding position 7 between the upper electrode 6 and the lower electrode 8 and the pre-gap 5 at the middle test panel 2, and the upper welding position 7 and the middle test panel 2 are contacted. At this time, a prepared gap 5 remains around the support foot 4 due to the support of the support foot 4.

Further, the welding stage includes preheating and welding. The preheating current I1=3kA and the preheating time T1=40ms. Welding current I2=7kA, welding time T2=300ms, I2 > 1.5i1 needs to be satisfied. The preparation time C =40ms is set between the preheating current and the welding current, and C is required to be more than or equal to 20ms. In the welding phase, a welding current flows between the upper electrode 6 and the lower electrode 8. Part of the current flows from the upper electrode 6 to the lower electrode 8 through the upper welding position 7, the middle test plate 2 and the lower welding position 9 at the upper welding position 7 and the middle test plate 2; the other part of the current flows from the upper electrode 6 to the lower electrode 8 through the second test plate 3, the supporting legs 4, the intermediate test plate 2 and the first test plate 1.

Further, as shown in fig. 3, the welding current is stopped, and the pressure of the upper electrode 6 and the lower electrode 8 is maintained until the welding is completed, and the molten material is solidified to form a nugget 10. At this stage, the welding current is reduced to 0, the pressure of the upper electrode 6 and the lower electrode 8 is kept for 100ms until the welding is completed, and the molten material is solidified to form a weld nugget 10. The diameter of the nugget 10 at the interface between the first test plate 1 and the middle test plate 2 which are finally formed is 4.8mm; the nugget 10 between the second test panel 3 and the intermediate test panel 2 was 6.1mm in diameter.

According to some embodiments, the first test plate 1 has a thickness h1 and a resistivity ρ 1, and the second test plate 3 has a thickness h2 and a resistivity ρ 2, wherein h2 > h1 and ρ 2 > ρ 1.

Based on the above examples, in some examples, the first test panel 1 is DX54D with a thickness of 0.65mm, i.e., h1=0.65mm, resistivity ρ 1 at 20 =0.106, and the surface has GI plating, melting point of the plating is 419 ℃, and thickness is 7 μm. The second test piece 3 was 1.2mm thick hot formed steel 22MnB5, i.e. h2=1.2mm, resistivity at 20 ℃ρ2=0.360, with no plating on the surface. The intermediate test plate 2 was 2.2mm thick hot formed steel 22MnB5. H2 > h1 and rho 2 > rho 1 are satisfied.

In contrast, resistance spot welding was performed on the multilayer board by a conventional welding method, and the comparative example was identical to the welding apparatus, the upper electrode 6 and the lower electrode 8 in the present application. As shown in fig. 4, the multilayer sheet of the comparative example was constructed such that the first test sheet 1 was DX54D with a thickness of 0.65mm, i.e., h1=0.65, and had a GI plating layer on the surface, the plating layer had a melting point of 419 ℃, and a thickness of 7 μm. The second test panel 3 was 1.2mm thick hot formed steel 22MnB5, i.e. h2=1.2mm, with no plating on the surface. The intermediate test plate 2 was 2.2mm thick hot formed steel 22MnB5. The first test plate 1, the middle test plate 2 and the second test plate 3 are overlapped, and the upper welding position 7 and the lower welding position 9 are mutually corresponding. In the comparative example, the support leg 4 was not provided in the multilayer sheet. The comparative example used a medium frequency resistance spot welder DB220 from OBARA. The comparative example used similar welding parameters as the inventive examples: upper electrode 6 and lower electrode 8 pressure F =4kN; the welding stage comprises preheating and welding, wherein the preheating current I1=3kA, the preheating time T1=40ms, the welding current I2=7kA, and the welding time T2=300ms; cooling time between preheating and welding current C =40ms; the pressure of the upper electrode 6 and the lower electrode 8 is maintained for 100ms until the welding is completed, and the molten material solidifies to form a nugget 10. The diameter of the finally formed weld nugget 10 at the interface between the first test plate 1 and the middle test plate 2 is 2.0mm; the nugget 10 between the second test panel 3 and the intermediate test panel 2 was 6.1mm in diameter 3. The diameter of the nugget 10 at the interface between the first test plate 1 and the intermediate test plate 2 which are finally formed in the application is 4.8mm; the diameter of the nugget 10 between the second test plate 3 and the middle test plate 2 is 6.1mm, which is firmer than the traditional welding mode.

Other embodiments of the present application will be apparent to those skilled in the art from consideration of the specification and practice of the embodiments disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the application and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains.

It will be understood that the present application is not limited to the precise arrangements that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the application is limited only by the appended claims.

Claims

1. A resistance spot welding method of a multilayer board, wherein the multilayer board comprises a first test board, a middle test board and a second test board, the resistance spot welding method comprising:

preparing supporting legs around the upper welding position of the second test plate;

stacking the first test plate, the middle test plate and the second test plate in sequence, wherein the supporting legs are arranged between the second test plate and the middle test plate to form a prefabricated gap between the second test plate and the middle test plate;

and controlling an upper electrode of the spot welding machine to press the upper welding position of the second test plate, and controlling a lower electrode of the spot welding machine to press the lower welding position of the first test plate for welding.

2. The method of claim 1, wherein controlling an upper electrode of the spot welder to press against an upper weld location of the second test panel and controlling a lower electrode of the spot welder to press against a lower weld location of the first test panel to weld comprises:

the upper electrode and the lower electrode tightly press the multilayer board, so that the prefabricated gap between the upper welding position and the middle test board is reduced to 0;

controlling the upper electrode and the lower electrode to be electrified so as to enable the upper welding position and the lower welding position to generate heat;

and maintaining the pressure of the upper electrode and the lower electrode until the welding is completed.

3. The method of claim 2, wherein said controlling the upper and lower electrodes to be energized to generate heat at the upper and lower weld locations comprises:

preheating the upper welding position and the lower welding position by introducing preheating current I1;

and welding between the upper welding position and the lower welding position by applying a welding current I2.

4. Method according to claim 3, characterized in that the preheating current I1 is related to the welding current I2 by: i2 is more than 1.5I1.

5. Method according to claim 3, characterized in that there is a preparation time C between the preheating current I1 and the welding current I2, which preparation time C satisfies: c is more than or equal to 20ms.

6. The method of claim 1, wherein the first panel has a thickness h1 and a resistivity ρ 1, and the second panel has a thickness h2 and a resistivity ρ 2, wherein h2 > h1 and ρ 2 > ρ 1.

7. The method of claim 1, wherein the intermediate panel comprises at least one intermediate panel.

8. The method of claim 1, wherein the support foot is at a distance L from the upper weld location, wherein L satisfies: l is more than or equal to 10 and less than or equal to 30mm.

9. The method of claim 1, wherein the support feet have a height H, wherein H satisfies: h is more than or equal to 0.1mm and less than 1mm.

10. The method of claim 1 wherein the shape of the support feet comprises cylindrical, prismatic, conical and pyramidal.