METHOD FOR PRODUCEING A WELDED LINK

Abstract

A method for manufacturing a welded link (100) comprising a metal link (1) and a nut (2) welded together is disclosed. The manufacturing method includes placing the nut (2) against a weld surface (11) of a plate-shaped section of the metal link (1) and pressing at least one part of the plate-shaped section or the nut (2) to bring the nut (2) into close contact with the weld surface (11). The manufacturing method further comprises irradiating a section of the nut (2) in close contact with the weld surface (11) with a beam (L) from a side opposite the weld surface (11) of the plate-shaped section to weld the metal link (1) and the nut (2) together by laser welding.

Description

BACKGROUNDThe present disclosure relates to a method for manufacturing a welded member.Japanese Unexamined Patent Application, Publication No. 2003-053567 discloses a method of laser welding a nut having protrusions and a steel plate together. In the welding method, the protrusions are brought into abutment with the steel plate, and then a beam is irradiated from the steel plate side to a gap formed by each of the protrusions between the nut and the steel plate.SUMMARYHowever, in the above-described welding method, the steel plate and the nut are separated at a position to be irradiated with the beam. Therefore, in some cases, the steel material melted by the jet flows to the nut but does not reach it, and the gap may remain. Moreover, in the above-described welding method, the nut may be inclined during welding due to thermal expansion or contraction in a portion irradiated with the beam, resulting in a welding failure between the nut and the steel plate. This has led to a problem of reduced joining strength between the nut and the steel plate.According to an aspect of the present disclosure, it is preferable to provide a method for improving a joining strength between a nut and a metal member.An aspect of the present disclosure is a method of manufacturing a welded member including a metal member and a nut welded together. The method for manufacturing the welded member includes bringing the nut into abutment with a welding surface of a plate-shaped portion of the metal member, and pressing at least one of the plate-shaped portion or the nut to bring the nut into close contact with the welding surface. The method for manufacturing the welded member further includes irradiating a portion of the nut that is in close contact with the welding surface with a beam from a side opposite to the welding surface of the plate-shaped portion to weld the metal member and the nut to each other by laser welding.With this configuration, in a state where the nut is in close contact with the welding surface, the metal member and the nut are welded together by the laser by pressing at least one of the plate-shaped portion or the nut. This reduces generation of a gap between the nut and the welding surface and a welding defect between the nut and the metal member caused by thermal expansion or contraction of a portion irradiated with the beam. Accordingly, it is possible to improve the joining strength between the nut and the metal member.According to an aspect of the present disclosure, pressing the nut against the weld surface may bring the nut into close contact with the weld surface.This configuration enables the nut to be fully pressed, so that a large pressing force can be easily applied.According to an aspect of the present disclosure, the nut may include protrusions. The projections can protrude to the welding surface and come into contact with the welding surface. The beam may be irradiated to each of the protrusions.In this configuration, the beam is irradiated to each of the protrusions, which are portions of the nut for abutting on the metal member. Even if a gap is formed by each of the protrusions between the nut and the welding surface, it is possible to improve the joining strength between the nut and the metal member.According to an aspect of the present disclosure, a beam diameter of the beam at a minimum intersection where a sectional plane included in an intersection zone formed by the intersection of the plate-shaped portion and a hypothetical irradiation zone of the beam has a minimum area may be 0.9 times or more as large as the longest width of each of the protrusions. The longest width may be a maximum length of each of the protrusions along a moving direction of a zone irradiated with the beam during laser welding.This configuration prevents the creation of deep holes in welded portions formed of the melted protrusions, which may be created due to a small size of the jet diameter, and enables appropriate melting of the protrusions.According to an aspect of the present disclosure, the metal member may be formed of a super high strength material.This configuration facilitates stabilization of the bonding strength between the super high strength material and the nut.BRIEF DESCRIPTION OF THE DRAWINGSEmbodiments of the present disclosure will be described below with reference to the accompanying drawings, in which: FIG. 1 is a schematic diagram showing a welded member; FIG. 2 is a schematic bottom view showing a nut; FIG. 3 is a schematic diagram showing a method of manufacturing the welded member; FIG. 4 is a schematic plan view showing a state in which the nut is held by nut holders; FIG. 5 is a diagram showing the minimum intersection of a beam when the beam is irradiated to an irradiation target in a focused or non-focused manner; and FIG. 6 is a diagram showing a beam diameter.DETAILED DESCRIPTION OF EMBODIMENTS[1. Configuration]<Geschweißt Member>The welded member 100 in FIG. 1 is a member including a metal member 1 and a nut 2 welded together by laser.The metal member 1 is, for example, a thin plate-shaped member having a plate thickness of 3.0 mm or less. Alternatively, it is preferable that a plate thickness of the metal member is 1.6 mm or less, and is preferably 1.0 mm. The metal member 1 is formed of a super high strength steel having a tensile strength of 1180 MPa or more, i.e., a super high strength material. Alternatively, it is preferable that a tensile strength of the metal member is 1470 MPa or more. The metal member 1 has a welding surface 11 to which a nut 2 is welded, and a non-welding surface 12 located on an opposite side of the welding surface 11. The metal member 1 further has at least one hole 13 penetrating the metal member 1 in its thickness directions, which are directions in which the welding surface 11 and the non-welding surface 12 are aligned.The nut 2 is, for example, a quadrilateral weld nut formed of iron or other metals for use in projection welding. Alternatively, an outer shape of the nut in a plan view may be a circle or a polygon that is not quadrilateral, and the nut may have a flange. In addition, the nut may have a shape configured for laser welding. As shown in FIGS. 1 and 2, the nut 2 has a screw hole 21, a first end surface 22, a second end surface 23, four protrusions 24, and side surfaces 25.The screw hole 21 is disposed so as to penetrate the nut 2. A screw or the like is inserted into the screw hole 21 for fastening.The first end surface 22 surrounds an opening at one end of the screw hole 21, and the second end surface 23 surrounds an opening at the other end of the screw hole 21, and the side surfaces 25 connect the first end surface 22 and the second end surface 23 to each other. In the present invention,In one embodiment, the side surfaces 25 are formed of four surfaces, two of which, which are adjacent to each other, are orthogonal to each other.The protrusions 24 are portions that are melted by laser welding and protrude with respect to the first end surface 22. The projections 24 protrude to the welding surface 11 side of the metal member 1 to abut on the welding surface 11. In the present embodiment, each of the protrusions 24 extends from the side surfaces 25 and the first end surface 22 so as to cover a corner located at a position where the side surfaces 25 and the first end surface 22 intersect. Alternatively, the protrusions may extend only from the side surfaces or may protrude only from the first end surface. In the present embodiment, the four protrusions 24 are provided so as to surround the opening 21A at approximately equal intervals. Specifically, each of the protrusions 24 is positioned at a corresponding corner of the nut 2. Alternatively, the number of the protrusions may be, for example, three or five or more.Each of the projections 24 has a front end face 241 for bearing against the welding surface 11. As shown in FIG. 2, the front end surface 241 has a semi-circular outer shape, and a straight part of a contour of the front end surface 241 faces a central axis A passing through a center of the screw hole 21 of the nut 2. Alternatively, the protrusions may have various shapes. In the following description, portions in which the metal member 1 and the nut 2 are welded to each other and which are formed by melting the metal member 1 and the protrusions 24 by laser welding are referred to as welded portions 24A< Device>Next, referring to FIGS. 3 and 4, a laser welding apparatus 200 will be explained in detail. FIG. 3 shows a state in which the laser welding apparatus 200 laser-welds the metal member 1 and the nut 2. FIG. 4 shows a state in which the nut 2 is held by a nut holder 6 described later. The laser welding apparatus 200 includes a link fixing clamp 3, a clamp bracket 4, a clamping device 5, the nut holder 6, a pressing cylinder 7, and a laser beam device 8.The link fixing terminal 3 and the terminal holder 4 are devices arranged to face each other in the upward and downward direction and allow the metal link 1 to be placed and held therebetween. The terminal support 4 is positioned below the link fixing terminal 3. In the present embodiment, the terminal support 4 is configured to provide an internal space for placing the nut 2 to be welded to the metal member 1. The member fixing clamp 3 is configured to provide a space above the above-described internal space to irradiate the metal member 1 with a beam L from the laser beam device 8 described later. For example, as shown in FIG. 3, the member fixing terminal 3 and the terminal support 4 hold a first end portion 14 and a second end portion 15 of the metal member 1 therebetween.The clamping device 5 is a device for fixing the link fixing clamp 3 and the clamp carrier 4. The clamp device 5 is disposed so as not to interfere with the beam emitted from the laser beam device 8 described later. Alternatively, the clamping device may also have a function of pressing down the member fixing clamp to press the metal member 1 against the nut 2.The nut holder 6 is a device for holding the nut 2, and the nut holder 6 holds the nut 2 such that the protrusions 24 of the nut 2 face upward. The nut holder 6 has a base 61 and four retaining detents 62.The base 61 is a plate-shaped member having a quadrangular outer shape in a plan view on which the nut 2 is to be placed. The base 61 has a contact surface 611 for abutting against the second end surface 23 of the nut 2.The retaining detents 62 are portions that protrude with respect to the contact surface 611 of the base 61 and are to abut against the side surfaces 25 of the nut 2. In the present embodiment, as shown in FIG. 3, each of the retaining detents 62 extends from a corresponding end surface of the base 61. alternatively, the retaining detents may protrude from a part of the contact surface of the base that is not to abut on the nut 2. In the present embodiment, as shown in FIG. 4, the four holding detents 62 are provided so as to surround the base 61 at approximately equal intervals. Specifically, each of the retaining detents 62 is positioned at a corresponding substantial center of four surfaces that form the end surfaces of the base 61. Alternatively, the number of holding detents may be, for example, two or three. As mentioned above, the four protrusions 24 of the nut 2 are respectively positioned at four corners of the nut 2. Thus, in a state where the nut 2 is placed on the base 61, each of the protrusions 24 of the nut 2 is located between two of the holding detents 62 adjacent to each other.Thereby, it is easy to position the nut 2 with respect to the nut holder 6 in the laser welder 200. Moreover, the four retaining detents 62 can prevent the nut 2 from rotating about the central axis A of the nut 2.The impression cylinder 7 is a device for pressing the nut 2 against the welding surface 11 of the metal member 1. the impression cylinder 7 is disposed within the above-described internal space formed by the clamp bracket 4 and positioned under the nut holder 6. The pressing cylinder 7 presses the nut holder 6 upward to press the nut 2 against the welding surface 11.The laser beam device 8 is a device positioned above the clamping device 5 and configured to radiate the beam L in a downward direction. The laser irradiation device 8 is configured such that a size of a beam diameter of the beam L is changeable by defocusing. In the present embodiment, the beam L is irradiated focused on an irradiation target. As illustrated in the irradiation target M 1 in FIG. 5, focused means that a focal point H of the beam L is focused behind the irradiation target M 1. Meanwhile, the beam L may not be irradiated in focus on the irradiation target. As illustrated in the irradiation target M 2 in FIG. 5, out of focus means that the focal point H of the beam L is focused in front of the irradiation target M 2. However, in the case of focusing, a diameter of an irradiation zone of the beam L along a direction in which the beam L is irradiated is reduced, so that it is easier to concentrate heat of the beam L to the irradiation target M 1 than in the case of non-focusing. As shown in FIGS. 5 and 6, a beam diameter d refers to the diameter of the irradiation zone of the beam L at a minimum intersection L 1 at which an intersection plane included in either an intersection zone R 1 or an intersection zone R 2 formed by the intersection of either the irradiation target M 1 or the irradiation target M 2 and a hypothetical irradiation zone of the beam L has a minimum area. The hypothetical irradiation zone of the beam L is the irradiation zone of the beam L when the irradiation target M 1, M 2 is not present. The sectional plane is a plane located at any part in thickness directions of the irradiation target M 1, M 2 and extending substantially perpendicular to thickness directions thereof. Alternatively, the laser beam apparatus may include a variable member that changes a light path, such as a diffractive optical element (DOE), to make a size of the beam diameter variable.<Method of Manufacturing Welded Member Using Laser Welding Apparatus>A method of manufacturing the welded member 100 using the laser welding apparatus 200 will be described with reference to FIGS. 2 and 3.First, the nut 2 is brought into abutment with the welding surface 11 of the metal member 1. More specifically, the nut 2 is placed with the upward projections 24 on the nut holder 6 to be placed on the impression cylinder 7. Then, the metal member 1 is placed on the nut 2 such that the screw hole 21 of the nut 2 and the hole 13 of the metal member 1 are aligned with each other and the protrusions 24 and the metal member 1 abut each other. Subsequently, the metal member 1 disposed on the nut 2 is fixed by the member fixing clamp 3, the clamp bracket 4, and the clamping device 5.Next, the nut 2 is pressed against the metal member 1 by the pressing cylinder 7, in particular upward. Thereby, the front end surfaces 241 of the protrusions 24 of the nut 2 are brought into close contact with the welding surface 11 of the metal member 1. As mentioned above, the metal member 1 is fixed by the member fixing clamp 3, the clamp bracket 4, and the clamping device 5, thereby preventing the metal member 1 from being raised even when a force F applied from the pressing cylinder 7 to press the nut 2 is applied to the metal member 1.Next, the laser beam device 8 irradiates a portion of the nut 2 that is in close contact with the welding surface 11 with the beam L from the non-welding surface 12 side of the metal member 1, and welds the metal member 1 and the nut 2 to each other by laser. In the present embodiment, the beam L is irradiated onto the protrusions 24 of the nut 2 from the non-welding surface 12 side. Specifically, the beam L impinges on the non-welding surface 12 of the metal member 1, and then the heat of the beam L first melts the metal member 1, after which further melting is performed by the heat of the beam L, thereby melting the protrusions 24. Subsequently, four welded portions 24A are formed by cooling molten portions of the metal member 1 and the protrusions 24.In the present embodiment, one protrusion 24 is selected from the four protrusions 24, and the beam L is irradiated on the one selected protrusion 24 first. Thereafter, other protrusions 24 are sequentially selected in the clockwise direction, and the beam L is sequentially irradiated to each of the other protrusions 24. As a result, in the present embodiment, four welded portions 24A are formed.The irradiation zone of the beam L moves in straight lines along the welding directions shown by arrows in FIG. 2, so that the beam L forms the welded portions 24A. In an example shown in FIG. 2, the welding directions are along the first end face 22 of the nut 2 and parallel to the straight parts of the contours of the front end faces 241 of the protrusions 24. In an example shown in FIG. 2, the longest width W is a diameter of a semicircle formed by the contour of the front end face 241 of each of the protrusions 24. For example, the longest width W of each of the protrusions 24 is about 2 mm.In the present embodiment, the beam L is irradiated focused on the metal member 1 that is the irradiation target of the beam L. As shown in FIG. 3, the minimum intersection L 1 of the beam L is a location on the welding surface 11 of the metal member 1 where the protrusions 24 are in close contact. Alternatively, the minimum intersection of the beam is not limited to the location on the welding surface 11 where the protrusions 24 are in close contact, and may be located at any location in the metal member 1 along the thickness directions thereof. For example, if the beam is not focused on the metal member 1, the minimum intersection of the beam may be on the non-welding surface 12 of the metal member 1. The beam diameter d of the beam L is set to 0.3 mm or more. In the present embodiment, the beam diameter d is 0.9 times or more as large as the longest width W of each of the protrusions 24. Specifically, when the longest width W of each of the protrusions 24 is about 2 mm, the beam diameter d is set to about 1.8 mm, with the longest width W and the beam diameter d substantially coincident with each other.[2. Effects]According to the embodiment described above in detail, the following effects can be obtained.(2a) In the present embodiment, the nut 2 has the four protrusions 24, and the beam L is irradiated on each of the protrusions 24, which is a portion of the nut 2 abutting on the welding surface 11 of the metal member 1. Therefore, in the configuration of the present embodiment, welding defects are less likely to occur than in a case where the beam L is irradiated to a gap between the nut 2 and the welding surface 11. Thereby, the joining strength between the nut 2 and the metal member 1 can be improved.(2b) In the present embodiment, the nut 2 is pressed against the metal member 1 by the pressing cylinder 7. As a result, in a state where the protrusions 24 of the nut 2 are in close contact with the welding surface 11 of the metal member 1, the beam L is irradiated to each of the protrusions 24 to form the welded portions 24A. Therefore, a gap is less likely to be formed between each of the welded portions 24A and the welding surface 11. Even if the thermal expansion or contraction of a portion irradiated with the beam L generates a force acting in a direction that causes the nut 2 to tilt during laser welding, the above-described pressure prevents such a tilt, so that welding defects between the nut 2 and the metal member 1 are less likely. Accordingly, it is possible to further improve the joining strength between the nut 2 and the metal member 1.(2c) In the present embodiment, the beam L is irradiated onto the nut 2 from the non-welding surface 12 side of the metal member 1. Here, for example, when the metal member 1 is pressed to press the nut 2 against the welding surface 11, it is necessary to press a portion of the metal member 1 in which the nut 2 is not located, such as the first end portion 14 and the second end portion 15 of the metal member 1, so as not to interfere with the beam L. In this case, when a pressing force applied to the metal member 1 is increased, a failure such as bending may occur in the metal member 1. On the other hand, as in the present embodiment, when pressing the nut 2 with the pressing cylinder 7 to press the nut 2 against the welding surface 11, it is possible to completely press the nut 2 without hindering the jet L. This facilitates application of a large pressing force to the nut 2. as a result, it is easier to improve a degree of close contact between the protrusions 24 of the nut 2 and the welding surface 11.(2d) In the present embodiment, the beam diameter d is substantially equal to the longest width W of each of the protrusions 24. preventing the creation of a hole that may be created in laser welding due to a small size of the beam diameter, such as a deep hole in each of the welded portions 24A or a through hole penetrating each of the welded portions 24A. When the hole is formed in the welded portions, the welding strength tends to be lowered. Thus, in the present embodiment, it is possible to melt the protrusions 24 adequately while preventing the decrease in joining strength caused by each of the welded portions 24A.(2e), for example, when projection welding is used to weld the nut to the metal member formed of the super high strength material having a thin plate thickness, a distance between the projections and an electrode used for projection welding becomes smaller. As a result, heat supplied to the protrusions easily escapes, and stress caused by thermal contraction or the like tends to concentrate in the welded portions, so that the joining strength between the nut and the metal member tends to become unstable. On the other hand, as in the present embodiment, when laser welding is used to weld the nut 2 to the metal member 1 formed of the super high tensile material having the thin plate thickness, the heat supplied to the protrusions 24 is less likely to escape, and the stress caused by thermal contraction or the like tends not to be concentrated in the welded portions 24A. Thus, the joining strength between the nut 2 and the metal member 1 can be easily stabilized. Moreover, an average crush peel strength of the nut 2 with respect to the metal member 1 tends to be higher. As a result, it is possible to improve the quality of the welding member 100.[3. Other Embodiments]Heretofore, the embodiment of the present disclosure has been described. However, it goes without saying that the present disclosure is not limited to the above-described embodiment and may take various forms.(3a) In the above-described embodiment, the metal member 1 is a plate-shaped member. However, the shape of the metal member is not limited thereto. For example, the metal member may have various shapes, and a plate-shaped portion has a thin plate thickness. In a configuration in which the metal member has the plate-shaped portion, the nut 2 is welded to the welding surface of the plate-shaped portion.(3b) In the above-described embodiment, pressing the nut 2 against the metal member 1 brings the protrusions 24 of the nut 2 into close contact with the welding surface 11 of the metal member 1. For example, the laser welding apparatus may include a device that presses the metal member 1 against the nut 2, and both the nut 2 and the metal member 1 may be pressed in such directions that the nut 2 and the metal member 1 come into close contact with each other. Moreover, for example, when the nut 2 is fixed, only the metal member 1 may be pressed against the nut 2.(3c) In the above-described embodiment, the nut 2 has protrusions 24. However, the nut does not have to have any protrusions. In a configuration in which the nut does not have a protrusion, the beam L is irradiated to a specific location to be welded between portions of the nut that are in close contact with the welding surface.(3d) In the above-described embodiment, the jet diameter d is substantially equal to the longest width W of each of the protrusions 24. For example, the beam diameter may be shorter than the longest width W. In particular, when the longest width W is about 2 mm, the beam diameter may be shorter than the longest width W and may be, for example, 0.3 mm or more. The beam diameter may be longer than the longest width W, for example.(3e) The above-described embodiment shows a configuration in which the metal member 1 is formed of super high strength material. However, a metal type of the metal member is not limited thereto. The metal member may be formed of another metal.(3f) In the above-described embodiment, the four projections 24 are welded clockwise one after another. However, the projections may be welded counterclockwise one after another. Moreover, for example, after welding a selected protrusion, another protrusion may be selected and welded diagonally opposite to the selected protrusion. Moreover, for example, protrusions may be simultaneously welded by splitting a beam into beams or using multiple beam sources that emit beams.(3g) In the above-described embodiment, the nut holder 6 has retaining detents 62. However, for example, when the laser welding apparatus includes a camera, a sensor, or the like and is configured to recognize a position of each of the protrusions 24 with the camera, the sensor, or the like, the nut holder may not have any holding locks. When the nut 2 is placed on the nut holder without retaining detents, the protrusions 24 can be easily slid. However, when the laser welding apparatus has the above-described configuration, it is possible to change a position at which the beam is irradiated and irradiate the beam to each of the protrusions 24, even if the protrusions 24 are displaced.(3h) In the above-described embodiment, the irradiation zone of the beam L moves in straight lines. However, the irradiation zone of the beam L may move to draw a curved line or a circle, for example.(3i) In laser welding, a bolt or the like may be inserted into the screw hole 21 of the nut 2 to prevent spatter from adhering to the non-welding surface 12 of the nut 2. Moreover, the laser welding apparatus may be provided with an air transmitter so that the air prevents spatter from adhering to the non-welding surface 12 of the nut 2.(3j) A function performed by a single element in the above-described embodiments may be achieved by a plurality of elements, or functions performed by a plurality of elements may be achieved by a single element. Further, in the above-described embodiments, a part of a configuration may be omitted. Moreover, at least a part of a configuration in the above-described embodiments may be added to or replaced with another configuration in the above-described embodiments.[4. Technical Idea Published Herein][Item 1]A method of manufacturing a welded member having a metal member and a nut welded together, the method comprising:contacting the nut with a welding surface of a plate-shaped portion of the metal member, and pressing at least one of the plate-shaped portion or the nut to bring the nut into close contact with the welding surface, andirradiating a portion of the nut that is in close contact with the welding surface with a beam from a side opposite to the welding surface of the plate-shaped portion to weld the metal member and the nut to each other by laser welding.[Item 2]The method for manufacturing a welded member according to Item 1, wherein pressing the nut against the welding surface brings the nut into close contact with the welding surface.[Item 3]The method for manufacturing a welded member according to Item 1 or 2, wherein the nut has protrusions protruding toward the welding surface to abut on the welding surface, and wherein the beam is irradiated on each of the protrusions.[Item 4]The method for manufacturing a welded member according to Item 3, wherein a beam diameter of the beam at a minimum intersection at which a sectional plane included in an intersection zone formed by the intersection of the plate-shaped portion and a hypothetical irradiation zone of the beam has a minimum area is 0.9 times or more as large as the longest width of each of the protrusions, and wherein the longest width is a maximum length of each of the protrusions along a moving direction of a zone irradiated with the beam during laser welding.[Item 5]The method for manufacturing a welded member according to any one of Items 1 to 4, wherein the metal member is formed of a super high strength material.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedJP 2003-053567

[0002]

Claims

A method for manufacturing a welded member (100) having a metal member (1) and a nut (2) welded together, the method comprising: abutting the nut (2) against a welding surface (11) of a plate-shaped portion of the metal member (1) and pressing at least one of the plate-shaped portion or the nut (2) to bring the nut (2) into close contact with the welding surface (11), and irradiating a portion of the nut (2) that is in close contact with the welding surface (11) with a beam (L) from a side opposite to the welding surface (11) of the plate-shaped portion to weld the metal member (1) and the nut (2) to each other by laser welding.The method for manufacturing a welded member (100) according to claim 1, wherein pressing the nut (2) against the welding surface (11) brings the nut (2) into close contact with the welding surface (11).The method for manufacturing a welded member (100) according to claim 1 or 2, wherein the nut (2) has protrusions (24) protruding toward the welding surface (11) to abut against the welding surface (11), and wherein the beam (L) is irradiated to each of the protrusions (24).The method for manufacturing a welded member (100) according to claim 3, wherein a beam diameter (d) of the beam (L) at a minimum intersection (L1) at which a sectional plane included in an intersection zone (R1, R2) formed by the intersection of the plate-shaped portion and a hypothetical irradiation zone of the beam (L) has a minimum area may be 0.9 times or more as large as the longest width (W) of each of the protrusions (24), and wherein the longest width (W) is a maximum length of each of the protrusions (24) along a moving direction of a zone irradiated with the beam (L) during laser welding.The method for manufacturing a welded member (100) according to claim 1 or 2, wherein the metal member (1) is formed of a super high strength material.

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