Differential thick plate stitch welding method and system

Abstract

The present application relates to the technical field of welding, and provides a combined spot welding method and system for differential-thickness plates, which comprises the following steps: selecting at least two plate materials with thickness difference, forming a conductive silver-based layer on one side of the plate material with the thinnest thickness, and sequentially attaching the remaining plate materials to the other side of the plate material with the thinnest thickness. A backing plate is attached to the outer surface of the conductive silver-based layer. First and second electrode rods with different diameters are selected, and the first and second electrode rods are respectively placed on the outer side of the backing plate and the outer side of the remaining plate materials, and the at least two plate materials are welded through the first and second electrode rods. The penetration rate of the thin plate side is increased from 20% to 50%, greatly improving the penetration rate, making the welding between the plate materials more stable, and improving the product quality.

Description

Technical Field

[0001] This invention relates to the field of welding technology, and in particular to a method and system for spot welding of plates with varying thicknesses. Background Technology

[0002] Resistance spot welding is a connection method with stable welding quality, high production efficiency, and easy mechanization and automation, and it is widely used in various manufacturing fields. When welding two plates with different thicknesses, the penetration rate at the thinner plate is generally low during the spot welding process, and may even fail to meet the standard requirements, seriously affecting product quality. Summary of the Invention

[0003] This invention provides a spot welding method for plates with different thicknesses, which solves the problems of low penetration rate on the thinner plate side when welding plates with different thicknesses in the prior art, affecting product quality, so as to improve the penetration rate on the thinner plate side and improve product quality.

[0004] The present invention also provides a spot welding system for differential thickness plates.

[0005] This invention provides a method for spot welding composite plates of varying thicknesses, comprising the following steps:

[0006] Select at least two plates with a thickness difference, form a conductive silver base layer on one side of the thinnest plate, and then attach the remaining plates to the other side of the thinnest plate in sequence.

[0007] A pad is attached to the outer surface of the conductive silver base layer;

[0008] Select a first electrode rod and a second electrode rod with different diameters, place the first electrode rod and the second electrode rod on the outside of the pad and the outside of the remaining plates respectively, and weld at least two plates through the first electrode rod and the second electrode rod;

[0009] The diameter of the first electrode rod is smaller than the diameter of the second electrode rod.

[0010] According to a method for spot welding differential thickness plates provided by the present invention, the steps of selecting at least two plates with a thickness difference, forming a conductive silver base layer on one side of the thinnest plate, and sequentially bonding the remaining plates to the other side of the thinnest plate specifically include:

[0011] Two plates with a thickness difference are selected, namely a thin plate and a thick plate. A conductive silver-based material is coated on the outer surface of the thin plate to form a conductive silver base layer with a thickness of 10-20μm. The thick plate is then attached to the side of the thin plate away from the conductive silver base layer.

[0012] According to the present invention, a method for spot welding of differential thickness plates is provided, wherein the thickness of the thin plate is t1 and the thickness of the thick plate is t2;

[0013] Wherein, 2t1 > t2 > t1, and the thickness of the pad is 0.3 mm;

[0014] Alternatively, t2 > 3t1, and the thickness of the pad is 0.5mm.

[0015] According to a method for spot welding differential thickness plates provided by the present invention, the steps of selecting at least two plates with a thickness difference, forming a conductive silver base layer on one side of the thinnest plate, and sequentially bonding the remaining plates to the other side of the thinnest plate specifically include:

[0016] Three plates with different thicknesses are selected, namely a thin plate, a relatively thick plate, and a thick plate. A conductive silver-based material is coated on the outer surface of the thin plate to form a conductive silver base layer with a thickness of 10-20 μm. The thick plate and the relatively thick plate are attached to the side of the thin plate away from the conductive silver base layer.

[0017] According to the present invention, a method for spot welding of plates with different thicknesses is provided, wherein the thickness of the thin plate is t3, the thickness of the thicker plate is t4, and the thickness of the thicker plate is t5.

[0018] Wherein, t5 > t4 > t3, and t5 > 3t3, and the thickness of the pad is 0.8 mm.

[0019] According to the present invention, a method for spot welding differential thickness plates is provided, wherein the step of attaching a backing plate to the outer surface of the conductive silver substrate specifically includes:

[0020] The pad is attached and fixed to the outer surface of the conductive silver base layer by at least one of the following methods: bonding, tooling, and fastener fixing.

[0021] According to the present invention, a method for spot welding differential thickness plates is provided, wherein the thickness of the backing plate is 0.3-0.8 mm.

[0022] According to a method for spot welding differential thickness plates provided by the present invention, the steps of selecting a first electrode rod and a second electrode rod with different diameters, placing the first electrode rod and the second electrode rod on the outer side of the pad plate and the outer side of the remaining plates respectively, and welding at least two plates using the first electrode rod and the second electrode rod specifically include:

[0023] Select an electrode with a diameter of 8mm and an end spherical radius of 200mm as the first electrode rod, and select an electrode with a diameter of 16mm and an end spherical radius of 200mm as the second electrode rod. Place the first electrode rod and the second electrode rod on the outside of the pad and the outside of the remaining plates, respectively. Weld at least two plates using the first electrode rod and the second electrode rod with a preset current intensity, preset welding time, and preset cooling time.

[0024] According to the present invention, the ratio between the preset current intensity, the preset welding time, and the preset cooling time is 1:28:4.

[0025] The present invention also provides a differential thickness plate combined spot welding system, comprising:

[0026] Central control unit;

[0027] The coating unit, electrically connected to the central control unit, is used to form a conductive silver base layer on one side of the thinnest sheet material.

[0028] The mounting unit is electrically connected to the central control unit and is used to attach a pad to the outer surface of the conductive silver base layer.

[0029] The first electrode rod and the second electrode rod are electrically connected to the central control unit, respectively, and are used to weld at least two plates on the outside of the pad and the outside of the remaining plates.

[0030] The differential thickness plate spot welding method provided in this invention improves the resistivity of the thinnest plate side by forming a conductive silver base layer on the outer side of the thinnest plate, thereby enhancing the nucleation ability and improving the penetration rate of the thinnest plate side. Adding a backing plate reduces the heat dissipation rate of the thinnest plate side during spot welding, further improving its penetration rate. Simultaneously, spot welding is performed using first and second electrode rods of different diameters, with the smaller diameter first electrode rod positioned on the thinnest plate side. This further reduces the heat dissipation rate on the thinnest plate side, causing the weld nugget to shift towards it, thus improving the penetration rate. Through the synergistic effect of these three methods, the penetration rate of the thinnest plate side is increased from 20% to 50%, significantly improving the penetration rate, resulting in more stable welding between plates and improved product quality.

[0031] The differential thickness plate combined spot welding system provided in this invention controls the coating unit, mounting unit, first electrode rod, and second electrode rod via a central control unit. A conductive silver base layer is formed on the outer side of the thinnest plate, increasing the resistivity of the thin plate side to enhance nucleation ability and thus improving the penetration rate. Adding a backing plate reduces heat dissipation on the thin plate side during spot welding, further improving its penetration rate. Simultaneously, spot welding is performed using first and second electrode rods of different diameters, with the smaller diameter first electrode rod positioned on the thin plate side. This further reduces heat dissipation on the thin plate side, causing the weld nugget to shift towards it, thus improving the penetration rate. Through the synergistic effect of these three methods, the penetration rate on the thin plate side is increased from 20% to 50%, significantly improving the penetration rate, resulting in more stable welding between plates and enhanced product quality. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0033] Figure 1 This is a schematic flowchart of the differential thickness plate combination spot welding method provided by the present invention;

[0034] Figure 2 This is a structural block diagram of the differential thickness plate combined spot welding system provided by the present invention;

[0035] Figure 3 This is a schematic diagram showing the state of the first and second electrode rods welding two plates.

[0036] Figure 4 This is a schematic diagram of the melt penetration rate of a thin plate with the diameters of the first electrode rods being 12mm, 10mm, and 8mm, and the second electrode rod being kept at 16mm. Detailed Implementation

[0037] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0038] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0039] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0040] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0041] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0042] The following is combined with Figures 1-4 The method for spot welding differential thickness plates according to the present invention includes the following steps:

[0043] S100. Select at least two plates with a thickness difference, form a conductive silver base layer on one side of the thinnest plate, and then attach the remaining plates to the other side of the thinnest plate in sequence.

[0044] S200, A pad is attached to the outer surface of the conductive silver base layer;

[0045] S300. Select a first electrode rod and a second electrode rod with different diameters, place the first electrode rod and the second electrode rod on the outside of the pad and the outside of the remaining plates respectively, and weld at least two plates through the first electrode rod and the second electrode rod.

[0046] The diameter of the first electrode rod is smaller than the diameter of the second electrode rod.

[0047] In this embodiment, by forming a conductive silver substrate on the outer side of the thinnest sheet, the resistivity of the thin sheet side can be increased to enhance nucleation capability, thereby improving the penetration rate of the thin sheet side. Adding a backing plate reduces the heat dissipation rate of the thin sheet side during spot welding, further improving its penetration rate. Simultaneously, spot welding is performed using first and second electrode rods of different diameters, with the smaller diameter first electrode rod positioned on the thin sheet side. This further reduces the heat dissipation rate on the thin sheet side, causing the weld nugget to shift towards it, thus improving the penetration rate. Through the synergistic effect of these three methods, the penetration rate of the thin sheet side is increased from 20% to 50%, significantly improving the penetration rate, resulting in more stable welding between sheets and enhanced product quality.

[0048] This method of spot welding for plates with different thicknesses is particularly suitable for spot welding between two plates with a thickness difference greater than 3 mm. It is also particularly suitable for spot welding and fixing between two or three plates.

[0049] like Figure 3 As shown, this is a welding process between two plates. The upper plate is thin, and the lower plate is thick. The electrode rod at the top of the thin plate is a first electrode rod with a smaller diameter, and the electrode rod at the bottom of the thick plate is a second electrode rod with a larger diameter. After coating the upper surface of the thin plate with a conductive silver base layer and attaching a backing plate, the weld nugget is shifted towards the thin plate, improving the penetration rate of the thin plate and enhancing the connection quality between the two plates after welding.

[0050] The main component of the conductive silver substrate is silver tin oxide (AgSnO2). Silver tin oxide can increase the contact resistance of the material surface, thereby increasing the resistivity of the thinnest plate side. Under the same spot welding parameters, the greater the contact resistance, the stronger the nucleation ability, thus improving the nucleation ability of the thin plate side and increasing the penetration rate of the thin plate side.

[0051] This embodiment takes two plates as an example. It selects at least two plates with a thickness difference, forms a conductive silver base layer on one side of the thinnest plate, and then sequentially attaches the remaining plates to the other side of the thinnest plate. Specifically, this includes:

[0052] Select two plates with a thickness difference, namely a thin plate and a thick plate. Coat the outer surface of the thin plate with a conductive silver base material to form a conductive silver base layer with a thickness of 10-20 μm. Then attach the thick plate to the side of the thin plate away from the conductive silver base.

[0053] When welding two plates, the thinner plate can be placed on top of the thicker plate, and a conductive silver-based material can be coated on the upper surface of the thinner plate to form a conductive silver base layer. During the welding process, the conductive silver base layer can increase the contact resistance on the thinner plate side, improve the nucleation ability on the thinner plate side, so that the weld nugget is located at the junction of the thinner and thicker plates, thereby improving the penetration rate on the thinner plate side and improving the welding quality.

[0054] At this point, with the pad on the outer surface of the conductive silver base layer and the asymmetrically arranged first and second electrode rods, the melting penetration rate can be increased from the original 20% to 50%.

[0055] The thickness of the thin plate is t1, and the thickness of the thick plate is t2. When 2t1 > t2 > t1, the thickness of the backing plate is 0.3 mm. When t2 > 3t1, the thickness of the backing plate is 0.5 mm. The thickness of the backing plate varies based on the thickness of the thin and thick plates. When the thickness of the thick plate is slightly greater than that of the thin plate (it should be noted that "slightly greater" here also requires that the thickness of the thick plate is at least 3 mm greater than that of the thin plate), the thickness of the backing plate can be set to 0.3 mm. In this case, the backing plate has the best effect on reducing the heat dissipation rate on the thin plate side and meets the welding requirements. When the thickness of the thick plate is much greater than that of the thin plate, the thickness of the backing plate can be set to 0.5 mm. In this case, the backing plate has the best effect on reducing the heat dissipation rate on the thin plate side and meets the welding requirements.

[0056] This embodiment takes three plates as an example. It selects at least two plates with a thickness difference, forms a conductive silver base layer on one side of the thinnest plate, and then sequentially attaches the remaining plates to the other side of the thinnest plate. The specific steps include:

[0057] Select three plates with different thicknesses: a thin plate, a relatively thick plate, and a thick plate. Coat the outer surface of the thin plate with a conductive silver-based material to form a conductive silver base layer with a thickness of 10-20μm. Then attach the thick plate and the relatively thick plate to the side of the thin plate away from the conductive silver base layer.

[0058] When welding three plates, the thinner plate can be placed on top of the thicker plate, and the thicker plate below it, sandwiching the thicker plate between the thinner and thicker plates. A conductive silver-based material is then coated onto the upper surface of the thinner plate, forming a conductive silver base layer. During welding, the conductive silver base layer increases the contact resistance on the thinner plate side, enhancing its nucleation ability. This allows the thicker plate to be melted through during nucleation, and also ensures that the thinner and thicker plates can be melted towards the thicker plate, thus improving the penetration rate on the thinner plate side and enhancing the weld quality.

[0059] At this point, with the pad on the outer surface of the conductive silver base layer and the asymmetrically arranged first and second electrode rods, the melting penetration rate can be increased from the original 20% to 50%.

[0060] The thickness of the thin plate is t3, the thickness of the thicker plate is t4, and the thickness of the thickest plate is t5. When t5 > t4 > t3, and t5 > 3t3, the thickness of the backing plate is 0.8 mm. At this thickness, the backing plate best reduces the heat dissipation rate on the thin plate side while still meeting welding requirements.

[0061] The steps of attaching a pad to the outer surface of the conductive silver substrate specifically include:

[0062] A pad is attached and fixed to the outer surface of the conductive silver substrate using at least one of the following methods: adhesive bonding, tooling fixation, and fastener fixation. When bonding, the pad can be attached and fixed to the outer surface of the conductive silver substrate by edge bonding, thus facilitating removal of the pad after welding. Removable fixing methods such as tooling fixation and fastener fixation also facilitate removal of the pad after welding. Tooling fixation can employ clamping fixtures that clamp the pad and the substrate at their edges to fix the pad's position. Fasteners can employ clamping locking devices that clamp the pad and the substrate at their edges to fix the pad's position.

[0063] The thickness of the backing plate is 0.3-0.8mm. The specific thickness can be selected according to the aforementioned plate thickness parameters. Furthermore, the shape of the backing plate can be selected based on the shape characteristics of the spot welding area, such as a strip-shaped backing plate or a circular backing plate. The backing plate can be made of stainless steel or copper, and the material can be adjusted to suit the material of the sheet metal.

[0064] The steps of selecting a first electrode rod and a second electrode rod of different diameters, placing the first electrode rod and the second electrode rod on the outer side of the pad and the outer side of the remaining plates respectively, and welding at least two plates using the first electrode rod and the second electrode rod specifically include:

[0065] Select an electrode with a diameter of 8 mm and an end spherical radius of 200 mm as the first electrode rod, and select an electrode with a diameter of 16 mm and an end spherical radius of 200 mm as the second electrode rod. Place the first electrode rod and the second electrode rod on the outside of the pad and the outside of the remaining plates, respectively. Weld at least two plates using the first electrode rod and the second electrode rod with a preset current intensity, preset welding time, and preset cooling time.

[0066] Spot welding is performed using an 8mm first electrode rod and a 16mm second electrode rod, with the first electrode rod located on the thin plate side and the second electrode rod located on the thick plate side or a relatively thick plate side. This reduces the heat dissipation rate on the thin plate side, shifts the weld nugget towards the thin plate side, and improves the penetration rate on the thin plate side.

[0067] like Figure 4 As shown in the figure, the diameters of the first electrode rods are 12mm, 10mm and 8mm respectively, and the second electrode rod is always kept at 16mm. The figure shows the melting penetration rate of the thin plate side. As can be seen from the figure, when the diameter of the first electrode rod is changed alone, the melting penetration rate (P in the figure) of the first electrode rod with a diameter of 10mm is the highest and the diameter of the fusion area (D in the figure) is the largest.

[0068] The ratio between the preset current intensity, preset welding time, and preset cooling time is 1:28:4. At this ratio, the penetration rate on the thinner plate side is optimal, and the weld formation is the best.

[0069] On the other hand, such as Figure 2 As shown, the present invention also provides a differential thickness plate combined spot welding system, including a central control unit, a coating unit, a mounting unit, a first electrode rod, and a second electrode rod. The coating unit is electrically connected to the central control unit and is used to form a conductive silver base layer on one side of the thinnest plate. The mounting unit is electrically connected to the central control unit and is used to attach a pad to the outer surface of the conductive silver base layer. The first electrode rod and the second electrode rod are respectively electrically connected to the central control unit and are used to weld at least two plates on the outer side of the pad and the outer side of the remaining plates.

[0070] In this embodiment, the central control unit controls the coating unit, mounting unit, first electrode rod, and second electrode rod respectively. A conductive silver base layer is formed on the outer side of the thinnest sheet, which increases the resistivity of the thin sheet side, improving nucleation capability and thus enhancing the penetration rate. Adding a backing plate reduces the heat dissipation rate on the thin sheet side during spot welding, further improving its penetration rate. Simultaneously, spot welding is performed using first and second electrode rods of different diameters, with the smaller diameter first electrode rod positioned on the thin sheet side. This further reduces heat dissipation on the thin sheet side, causing the weld nugget to shift towards it, thus improving the penetration rate. Through the synergistic effect of these three methods, the penetration rate on the thin sheet side is increased from 20% to 50%, significantly improving the penetration rate, resulting in more stable welding between sheets and enhanced product quality.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for spot welding composite plates of varying thicknesses, characterized in that, Includes the following steps: Three plates with different thicknesses are selected: a thin plate, a relatively thick plate, and a thick plate. A conductive silver-based material is coated on one side of the thin plate to form a conductive silver base layer. The thin plate is placed on top of the thick plate, and the relatively thick plate is placed below the thick plate, so that the thick plate is sandwiched between the thin plate and the relatively thick plate. The conductive silver base layer is located on the upper surface of the thin plate. The main component of the conductive silver substrate is silver tin oxide, and the thickness of the conductive silver substrate is 10-20 μm; A pad is attached to the outer surface of the conductive silver base layer; The thickness of the pad is 0.3-0.8 mm; Select a first electrode rod and a second electrode rod with different diameters, and place the first electrode rod and the second electrode rod on the outside of the pad and the outside of the thicker plate, respectively; weld the three plates with the first electrode rod and the second electrode rod at a preset current intensity, a preset welding time and a preset cooling time; the ratio between the preset current intensity, the preset welding time and the preset cooling time is 1:28:4; The diameter of the first electrode rod is smaller than the diameter of the second electrode rod.

2. The method for spot welding differential thickness plates according to claim 1, characterized in that, The thickness of the thin plate is t3, the thickness of the thicker plate is t4, and the thickness of the thickest plate is t5. Wherein, t5 > t4 > t3, and t5 > 3t3, and the thickness of the pad is 0.8 mm.

3. The method for spot welding differential thickness plates according to any one of claims 1-2, characterized in that, The step of attaching the pad to the outer surface of the conductive silver substrate specifically includes: The pad is attached and fixed to the outer surface of the conductive silver base layer by at least one of the following methods: bonding and tooling.

4. The method for spot welding differential thickness plates according to any one of claims 1-2, characterized in that, An electrode with a diameter of 8 mm and an end spherical radius of 200 mm was selected as the first electrode rod, and an electrode with a diameter of 16 mm and an end spherical radius of 200 mm was selected as the second electrode rod.

5. A spot welding system for plates with varying thicknesses, characterized in that, Used to perform the differential thickness plate combination spot welding method as described in any one of claims 1-4; The differential thickness plate combination spot welding system includes: Central control unit; The coating unit, electrically connected to the central control unit, is used to form a conductive silver base layer on one side of the thin plate; The mounting unit is electrically connected to the central control unit and is used to attach a pad to the outer surface of the conductive silver base layer. The first electrode rod and the second electrode rod are electrically connected to the central control unit, respectively, and are used to weld the three plates on the outer side of the pad and the outer side of the thicker plate.

Images