Plate material, joined body, plate material joining method, and plate material manufacturing method

Abstract

To provide a plate which can be joined smoothly by performing laser welding while preventing occurrences of defects, such as blow holes and burn-through, sufficiently, and to provide a joint body in which the plate is joined to a joined side plate, a joining method of the plate, and a production method of the plate.SOLUTION: A plate 11 formed of copper or copper alloy to be laser welded is overlapped with a joined side plate 13 formed of copper or copper alloy. Multiple groove parts 21 intersecting with a scanning direction A of a laser beam L are provided spaced apart from each other along the scanning direction A of the laser beam L on a surface of the plate 11 to which the laser beam L is radiated.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a plate material, a joined body, a method for joining plate materials, and a method for manufacturing plate materials. [Background technology]

[0002] For example, when joining copper alloy sheets together to produce heat dissipation members such as vapor chambers or electronic components, the copper alloy sheets are joined together by brazing or caulking. However, these joining methods have low productivity and require high equipment costs. In contrast, a joining method of laser welding copper alloy sheets together can achieve high productivity while reducing costs.

[0003] Patent Document 1 discloses a vapor chamber constructed by welding one plate-shaped member to another plate-shaped member, in which the thickness of the fusion zone of one plate-shaped member is thinner than the thickness of the fusion zone of the other plate-shaped member.

[0004] Furthermore, Patent Document 2 discloses that a surface layer made of a metal material that has a high absorption rate of laser light and a higher breaking strength than the metal material is formed on one surface of metal components that are stacked on top of each other, and that laser light is irradiated from above the surface layer to form a re-solidified portion from the surface of the surface layer to the inside of the metal component, thereby joining the two metal components. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2018 / 147283 [Patent Document 2] International Publication No. 2012 / 124255 Summary of the Invention [Problem to be solved by the invention]

[0006] Laser welding is highly productive because it can be done at high speeds, and is gaining attention as a joining method for sealing gaps between plates. To reduce the size and weight of copper or copper alloy sheets used in heat dissipation components, for example, thinner sheets with a total thickness of 0.3 mm or less are required. Copper has a low laser absorption rate in the solid state, but its absorption rate increases dramatically when it is molten. Therefore, when joining copper or copper alloy sheets by laser welding, the molten pool is unstable, and defects such as blowholes are likely to occur. In particular, defects such as burn-through may occur in extremely thin sheets.

[0007] When laser welding thin copper or copper alloy sheets together, as in Patent Document 1, simply increasing the thickness of a portion of the sheet or forming a surface layer on the surface irradiated with laser light, as in Patent Document 2, does not sufficiently prevent defects such as blowholes and burn-through. Moreover, the technique of Patent Document 1 increases the thickness of the fused portion of one of the plate-like members, which increases its weight. Furthermore, the technique of Patent Document 2 has difficulty joining members whose surface cannot be plated.

[0008] Therefore, an object of the present invention is to provide a plate material that can be smoothly laser welded and joined while sufficiently suppressing the occurrence of defects such as blowholes and burn-through, a joined body in which this plate material is joined to a plate material to be joined, a method for joining plate materials, and a method for manufacturing plate materials. [Means for solving the problem]

[0009] The present invention comprises the following configurations. (1) A plate material made of copper or a copper alloy that is overlapped with a joined side plate material made of copper or a copper alloy and laser welded, a surface to be irradiated with the laser beam has a plurality of grooves intersecting the scanning direction of the laser beam and spaced apart along the scanning direction of the laser beam; Board material. (2) The plate material according to (1) is joined to the plate material to be joined by a bead formed in a direction intersecting the groove portion. zygote. (3) The plate material described in (1) is placed on the plate material to be joined, a laser beam is irradiated along a direction intersecting the plurality of grooves formed in the plate material, thereby laser welding the plate material to the joined side plate material; How to join boards. (4) A method for manufacturing a plate material made of copper or a copper alloy that is overlapped with a side plate material to be joined that is made of copper or a copper alloy and laser welded, comprising the steps of: a plurality of grooves intersecting the scanning direction of the laser light are provided at intervals along the scanning direction of the laser light on an irradiated portion to be irradiated with the laser light during laser welding by laser processing, rolling processing, or press processing; Manufacturing method of boards. [Effects of the Invention]

[0010] According to the present invention, plate materials can be smoothly joined by laser welding while sufficiently suppressing the occurrence of defects such as blowholes and burn-through. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a perspective view schematically showing a state in which a plate material and a plate material to be joined are laser-welded together. [Figure 2] FIG. 2 is a plan view showing a groove formed in a plate material. [Figure 3] FIG. 3 is an enlarged plan view of a portion of the plate showing grooves formed in the plate. [Figure 4] FIG. 10 is a plan view showing a state in which a plate material and a plate material to be joined are laser-welded together. [Figure 5] FIG. 2 is a plan view of a joined body obtained by laser welding a plate material and a plate material to be joined. [Figure 6] FIG. 10 is a plan view of a portion of a joined body in which grooves of other shapes are formed and laser welded. [Figure 7] 10 is an image of a plate material with grooves formed therein. [Figure 8A] 10 is an image of the laser light irradiated side of a bonded body in which a plate material and a plate material to be bonded are bonded together. [Figure 8B]10 is an image of the side opposite to the laser light irradiation side in a joined body in which a plate material and a plate material to be joined are joined. [Figure 8C] 10 is an image of a cross section of a joint portion in a joined body in which a plate material and a plate material to be joined are joined. [Figure 9A] This is an image of the rear side of a plate material in a state where the plate material has not been sufficiently melted by the laser light and has not been penetrated. [Figure 9B] 10 is an image of the rear side of a plate material in a state where melt-through has occurred due to laser light. [Figure 10] 1 is a graph showing appropriate output ranges of laser light in an example and a comparative example. [Figure 11A] 10 is an image of the irradiated side of a plate material irradiated with laser light at the lower limit output in an example. [Figure 11B] 10 is an image of the side opposite to the irradiated side of a plate material irradiated with laser light at the lower limit output in an example. [Figure 12A] 10 is an image of the irradiated side of a plate material irradiated with laser light at the lower limit output in a comparative example. [Figure 12B] 10 is an image of the side opposite to the irradiated side of a plate material irradiated with laser light at the lower limit output in a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view that schematically shows how a plate material 11 and a plate material 13 to be joined are laser-welded together.

[0013] The plate material 11 according to this embodiment is joined to another plate material, that is, a plate material on the joining side (joined-side plate material) 13, by laser welding. The plate materials 11 and 13 are partially overlapped with each other, and this overlapping portion becomes an irradiated portion 15. Then, the irradiated portion 15 is irradiated with laser light L by a laser irradiation device 100, thereby laser welding the plate material 11 and the plate material 13 on the joining side. The laser light L is irradiated onto at least a partial range of the irradiated portion 15, and does not extend beyond the irradiated portion 15.

[0014] The plate materials 11 and 13 are plate materials made of copper or a copper alloy. In the case of a copper alloy, components contained in copper (Cu) include tin (Sn), nickel (Ni), zinc (Zn), magnesium (Mg), phosphorus (P), etc. Thin plates with a thickness of 0.10 mm to 1.0 mm are used as the plate materials 11 and 13. The plate thicknesses of the plate materials 11 and 13 may be the same, or one may be thicker than the other.

[0015] Fig. 2 is a plan view showing grooves 21 formed in the plate material 11. Fig. 3 is an enlarged plan view of a portion of the plate material 11 showing the grooves 21 formed in the plate material 11. As shown in FIGS. 2 and 3, a plurality of grooves 21 are arranged at intervals along the scanning direction A of the laser light L on the surface of the irradiated portion 15 of the plate material 11 that is irradiated with the laser light L.

[0016] Each groove 21 has a width W that is 1 to 2 times the thickness of the plate material 11, a depth D that is 1 / 3 or less the thickness of the plate material 11, and a pitch P that is 2 to 4 times the thickness of the plate material 11.

[0017] An example of a laser irradiation device 100 that irradiates the irradiated portion 15 with laser light L for laser welding is one equipped with a galvanometer scanner unit. In the laser irradiation device 100 equipped with a galvanometer scanner unit, a laser from a fiber laser oscillator is reflected by a galvanometer mirror, and then focused by a lens to irradiate the irradiated portion 15. With this laser irradiation device 100, the laser light L can be scanned at high speed and with high precision by controlling the angle of the galvanometer mirror attached to the rotation axis. However, the laser irradiation device 100 is not limited to this, and other types of irradiation devices may also be used.

[0018] Next, a joining method for laser welding the plate material 11 and the plate material 13 to be joined according to this embodiment will be described. (groove formation) A plurality of grooves 21 are formed in the plate material 11. The grooves 21 are formed by laser processing. Specifically, the laser beam L is wobbled while the laser irradiation device 100 is moved along the scanning direction A in the irradiated portion 15. As a result, the laser beam L is intermittently irradiated onto the irradiated portion 15 while periodically rotating, and a plurality of grooves 21 are formed that are spaced apart along the scanning direction A. By forming the grooves 21 in the plate material 11 by laser processing in this way, laser welding to the plate material 13 on the joining side, which is performed after processing the grooves 21, can be performed all at once, simplifying the manufacturing process.

[0019] The grooves 21 may be formed by rolling or pressing, not limited to laser processing using the laser irradiation device 100. When the grooves 21 are formed by rolling or pressing, a general manufacturing line can be used, and an increase in manufacturing costs can be suppressed.

[0020] (Laser welding) Next, the plate material 11 with the grooves 21 formed therein is placed on the plate material 13 to be joined. Then, the laser beam L from the laser irradiation device 100 is scanned onto the irradiated portion 15 of the plate material 11 placed on the plate material 13, from one end 15a to the other end 15b of the irradiated portion 15. As a result, as shown in FIG. 4 , the laser beam L is irradiated along the scanning direction A that intersects with the plurality of grooves 21 of the plate material 11, and a bead 23 is formed by laser welding the plate material 11 and the plate material 13 together.

[0021] When laser welding is performed using the laser light L from the laser irradiation device 100, the irradiated portion of the joint (irradiated portion 15) between the plate material 11 and the plate material 13 to be joined is melted at the irradiated portion of the laser light L, and the irradiated portion melts from the irradiated surface to the back surface of the plate material 13 to be joined, which is opposite to the side irradiated with the laser light L. This melted portion cools and solidifies and hardens, thereby forming a bead 23 continuously in a direction intersecting with the groove portion 21, as shown in FIG. 5. This results in a joined body 25 in which the plate material 11 and the plate material 13 to be joined are well joined.

[0022] As described above, with the plate material 11 of this configuration, by irradiating the laser light L so as to intersect with the multiple grooves 21, heat input is promoted from the thinner portions of the plate where the grooves 21 are located. This allows a molten pool to be formed with low power, and allows smooth laser welding to the plate material 13 to be joined while sufficiently suppressing the occurrence of defects such as blowholes and burn-through. Furthermore, when laser welding to the plate material 13 to be joined, the output range of the laser light L that can be welded is expanded, allowing the plate material 11 and the plate material 13 to be joined to be joined easily and with high quality.

[0023] In particular, the laser beam absorption rate of copper or copper alloys in the solid state is low (5% or less), but rapidly increases to several tens of percent or more once molten. Therefore, once melted, the molten pool becomes unstable, prone to defects such as spatter and blowholes, and burn-through occurs easily in thin plates. However, by forming multiple grooves 21 in the plate material 11 in advance and irradiating the plate material with laser beams intersecting the grooves 21 as described above, rapid melting is suppressed. That is, in this configuration, moderately thin portions are interspersed along the scanning direction A of the laser beam L. As a result, melting begins from the thin portions of the grooves 21 due to thermal conduction, and heat is conducted toward the periphery of the formed molten pool, resulting in heating of a wider area than the laser irradiation area. Although the energy absorption of the laser beam is increased in the molten portion, this, combined with thermal diffusion to the surrounding area, suppresses rapid melting. Therefore, melting begins even at low laser beam power, and even at high power, excessive heat input is suppressed due to thermal diffusion from the portion that began to melt earlier. This expands the range of laser beam power that can be used for welding.

[0024] The above effects are prominently achieved by optimizing the width of the grooves 21 to be 1 to 2 times the plate thickness, the depth D of the grooves 21 to be 1 / 3 or less of the plate thickness, and the pitch of the grooves 21 to be 2 to 4 times the plate thickness.

[0025] By laser welding the plate material 11 and the plate material 13 to be joined in this manner, a joint 25 is obtained in which the plate material 11 and the plate material 13 to be joined are joined with high quality by the bead 23 formed in a direction intersecting the groove portion 21.

[0026] Furthermore, according to the method for joining plate materials of this configuration, the plate material 11 is overlapped on the plate material 13 to be joined, and laser light L is irradiated along a direction intersecting the multiple groove portions 21, thereby enabling the plate material 11 and the plate material 13 to be joined to be joined well while suppressing melt-through.

[0027] Furthermore, when manufacturing the plate material 11 having the plurality of grooves 21, the formation of the grooves 21 by laser processing and the laser welding to the plate material 13 to be joined can be performed simultaneously, thereby simplifying the manufacturing process. When the grooves 21 are formed by rolling or pressing, a general rolling or pressing production line can be used, thereby making it possible to manufacture the plate material 11 made of copper or a copper alloy having the grooves 21 at low manufacturing costs.

[0028] In the above configuration example, the laser beam L is wobbled while moving the laser irradiation device 100 along the scanning direction A to form the curved grooves 21. However, the scanning pattern of the laser beam L is arbitrary. For example, as shown in FIG. 6 , the grooves 21 may be linear. When joining the plate material 11 to the plate material 13 to be joined, the plate material 11 and the plate material 13 to be joined may be laser-welded by irradiating the laser beam L along the scanning direction A that intersects with the linear grooves 21. In this case, too, laser welding between the plate material 11 and the plate material 13 to be joined can be performed smoothly while sufficiently suppressing the occurrence of defects such as blowholes and burn-through. Furthermore, when laser welding to the plate material 13 to be joined, the output range of the laser beam L that can be welded is expanded, making it easier to weld both materials. [Example]

[0029] The plate material 11 having the grooves 21 formed by laser processing was placed on the plate material 13 to be joined and laser-welded to produce a joined body 25, and the front, back and cross section of the welded portion of the produced joined body 25 were observed and evaluated. The plate material 11 and the plate material 13 to be joined were copper alloy plates with a thickness of 0.15 mm.

[0030] (groove formation) FIG. 7 is an image of the plate material 11 in which the grooves 21 are formed. As shown in Fig. 7, a plurality of grooves 21 were formed in the plate material 11. The laser processing of the grooves 21 was performed under the conditions of a laser beam scanning pattern of circular wobbling with a diameter of 1.6 mm and a frequency of 100 Hz, an output of 3 kW, and a welding speed of 7 m / min.

[0031] (laser welding) The plate material 11 provided with the grooves 21 was placed on the plate material 13 to be welded, and laser welding was carried out under the conditions of an output of 3 kW and a welding speed of 10 m / min.

[0032] (Evaluation results) Figures 8A to 8C are images of a bonded body 25 in which plate material 11 and plate material 13 are bonded together, where Figure 8A is an image of the side irradiated with laser light, Figure 8B is an image of the side opposite to the side irradiated with laser light, and Figure 8C is an image of a cross section at the bonded location.

[0033] As shown in Fig. 8A, a linear bead 23 was formed by laser welding on the surface of the plate material 11 on the side irradiated with the laser beam L, in a direction intersecting with the groove portion 21. Furthermore, as shown in Fig. 8B, a linear bead 23 was also formed on the surface of the plate material 13 on the side to be joined, opposite the side irradiated with the laser beam L, and the bead width was substantially uniform with little variation in the longitudinal direction, and there was no evidence of burn-through. Furthermore, as shown in Fig. 8C, a bead 23 was formed at the joint between the plate material 11 and the plate material 13 on the side to be joined, penetrating evenly throughout the thickness direction. Thus, a joined body 25 was obtained, having a welded portion that was stable in both appearance and cross section. [Example]

[0034] Laser light was linearly irradiated onto copper alloy plate materials P1 and P2, and the front and back surfaces of the laser light irradiated areas were observed to investigate the output range of the laser light that can be welded.

[0035] Figures 9A and 9B are images of the back side of a plate material Pb made of bare material that has been irradiated with laser light. Figure 9A is an image of the plate material Pb in a non-penetrating state where the laser light has not sufficiently melted it, and Figure 9B is an image of the plate material Pb in a state where it has been burned through.

[0036] To investigate the appropriate output range of the laser beam, the presence or absence of non-penetration (see Figure 9A) and burn-through (see Figure 9B) on the back surface of the irradiated area of ​​the laser beam was investigated, and the output that did not cause non-penetration or burn-through was determined to be the output range that can be welded.

[0037] <Plate material> (Example) Plate material P1: A copper alloy plate having a thickness of 0.2 mm and having multiple linear grooves N with a groove width of 190 μm and a pitch of 420 μm. (Comparative Example) Plate material P2: A copper alloy plate with a thickness of 0.2 mm made of bare material without grooves

[0038] <Laser light irradiation conditions> (Example) The laser beam was irradiated linearly along the scanning direction intersecting the plurality of grooves N at a scanning speed of 10 m / min. (Comparative Example) The laser beam was irradiated linearly at a scanning speed of 10 m / min.

[0039] <Evaluation results>

[0040] FIG. 10 is a graph showing the output range of the laser beam in the example and the comparative example.

[0041] (Example) As shown in FIG. 10, in the example, when laser light was irradiated at an output in the range of 2.0 kW to 2.6 kW, non-penetration and burn-through did not occur.

[0042] 11A and 11B are images of the appearance of the irradiated area when laser light is irradiated at the lower limit output in the example, where FIG. 11A is an image of the side irradiated with the laser light, and FIG. 11B is an image of the side opposite to the side irradiated with the laser light.

[0043] In the example, at a laser output of 2.0 kW, a linear bead B intersecting multiple grooves N was formed on the side irradiated with the laser light, as shown in Figure 11A, and a linear bead B without defects such as blowholes or burn-through was formed on the side opposite to the side irradiated with the laser light, as shown in Figure 11B.

[0044] (Comparative Example) As shown in FIG. 10, in the comparative example, when laser light was irradiated at an output in the range of 2.2 kW to 2.6 kW, non-penetration and burn-through did not occur.

[0045] 12A and 12B are images of the appearance of the irradiated area when laser light is irradiated at the lower limit output in the comparative example, where FIG. 12A is an image of the side irradiated with the laser light, and FIG. 12B is an image of the side opposite to the side irradiated with the laser light.

[0046] In the comparative example, at a laser output of 2.2 kW, a linear bead B was formed on the side irradiated with the laser light as shown in Fig. 12A. Also, a linear bead B without defects such as blowholes or burn-through was formed on the side opposite to the side irradiated with the laser light as shown in Fig. 12B.

[0047] In this way, by forming multiple grooves on the surface of the plate material to be irradiated with laser light and irradiating the laser light so that it intersects with these grooves, it was found that the weldable output range of the laser light during laser welding is expanded compared to when no grooves are provided, making it easier to join.

[0048] As such, the present invention is not limited to the above-described embodiments, and the present invention also contemplates the mutual combination of the various components of the embodiments, as well as modifications and applications by those skilled in the art based on the description in the specification and well-known techniques, and these modifications and applications are included in the scope of protection sought.

[0049] As described above, the present specification discloses the following: (1) A plate material made of copper or a copper alloy that is overlapped with a joined side plate material made of copper or a copper alloy and laser welded, A plate material having a surface to be irradiated with laser light, on which a plurality of grooves intersecting the scanning direction of the laser light are provided at intervals along the scanning direction of the laser light. With this plate material, by irradiating the laser beam so that it intersects with the multiple grooves, heat input is promoted from the thinner portions of the plate where the grooves are located. This allows for the formation of a molten pool at low power, and allows smooth laser welding to the plate material to be joined while sufficiently suppressing the occurrence of defects such as blowholes and burn-through. In addition, the weldable output range of the laser beam when laser welding to the plate material to be joined can be expanded, making joining easier.

[0050] (2) The plate material according to (1), wherein the grooves have a width dimension of 1 to 2 times the plate thickness, a depth dimension of 1 / 3 or less the plate thickness, and a pitch of 2 to 4 times the plate thickness. With this plate material, by optimizing the width, depth, and pitch of the grooves, portions with a moderate thickness are arranged along the scanning direction of the laser light, which prevents excessive heat input to the thin-walled portions having the grooves due to thermal conduction and suppresses burn-through when welding the plate material to the plate material to be joined.

[0051] (3) A joined body in which the plate material according to (1) or (2) is joined to the plate material to be joined by a bead formed in a direction intersecting the groove portion. According to this bonded body, the plate material and the plate material to be bonded are bonded well by the beads formed in a direction intersecting the grooves.

[0052] (4) The plate material described in (1) or (2) is placed on the plate material to be joined, A method for joining plate materials, comprising: irradiating the plate material with laser light in a direction intersecting with a plurality of grooves formed in the plate material, thereby laser welding the plate material to the plate material to be joined. According to this method for joining plate materials, the plate material is overlapped on the plate material to be joined, and laser light is irradiated along a direction that intersects with the multiple grooves, thereby enabling the plate material and the plate material to be joined to be joined well while suppressing burn-through.

[0053] (5) A method for manufacturing a plate material made of copper or a copper alloy that is overlapped with a side plate material to be joined that is made of copper or a copper alloy and laser welded, comprising the steps of: A method for manufacturing a plate material, comprising providing a plurality of grooves intersecting a scanning direction of the laser light at intervals along the scanning direction of the laser light in an irradiated portion that is irradiated with the laser light during laser welding by laser processing, rolling processing, or press processing. According to this method for manufacturing a plate material, when the grooves are formed by laser processing, processing of the grooves and laser welding to the plate material to be joined can be performed in one step, simplifying the manufacturing process. Furthermore, when the grooves are formed by rolling or pressing, a general manufacturing line can be used, so that a plate material made of copper or a copper alloy and having grooves can be manufactured at low manufacturing costs. [Explanation of symbols]

[0054] 11 Board material 13 Plate material (side plate material to be joined) 21 Groove 23 Bead 25 Zygote A Scanning direction L laser light Pitch W width dimension

Claims

1. A plate material made of copper or a copper alloy that is overlapped with a joined side plate material made of copper or a copper alloy and laser welded, a plurality of grooves intersecting a scanning direction of the laser light are provided at intervals along the scanning direction of the laser light on a surface to be irradiated with the laser light; The grooves have a width dimension that is 1 to 2 times the plate thickness, a depth dimension that is 1 / 3 or less of the plate thickness, and a pitch that is 2 to 4 times the plate thickness. Board material.

2. A welding method comprising the plate material according to claim 1 and the side plate material to be joined, The plate material has a joining portion overlapping the joined side plate material, and a bead formed along the joining portion in a direction intersecting the groove portion. zygote.

3. The plate material according to claim 1 is placed on the plate material to be joined, a laser beam is irradiated along a direction intersecting the plurality of grooves formed in the plate material, thereby laser welding the plate material to the joined side plate material; How to join boards.

4. A method for manufacturing a plate material made of copper or a copper alloy that is overlapped with a joined side plate material made of copper or a copper alloy and laser welded, comprising: a plurality of grooves intersecting a scanning direction of the laser light are provided at intervals along the scanning direction of the laser light by laser processing, rolling processing, or press processing in an irradiated portion to be irradiated with the laser light during laser welding; The grooves have a width dimension that is 1 to 2 times the plate thickness, a depth dimension that is 1 / 3 or less of the plate thickness, and a pitch that is 2 to 4 times the plate thickness. Manufacturing method of boards.

Images