Method for cutting and welding a cutting element

Abstract

To provide a cutting and welding method of a cutting member capable of reducing time and work load by replacing cutting by gas cutting with cutting by a plasma cutting device.SOLUTION: The method for cutting and welding the cut member includes a cutting step of cutting the cut member 21 from the steel plate 20, and a welding step of welding the cut member 21 to a position where the cut member 21 of the steel plate 20 is present, and closing the provided hole. The cutting-out step includes a first cutting step in which a groove is provided on one side of the removal portion 22, such as the side where the plasma cutting device is present, and a second cutting step in which a groove is provided on the other side of the removal portion 22, such as the side where the plasma cutting device is present. In the welding process, the cutting member 21 is welded in a posture turned over in the thickness direction of the steel plate 20 from a posture in which the cutting member 21 exists with respect to the steel plate 20.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a cutting and welding method for a cutting member, and more particularly to a cutting and welding method for a cutting member, in which a hole, such as a construction hole, is opened by temporarily cutting out a cutting member, and then the hole is closed by welding the cutting member. [Background technology]

[0002] As described in Patent Document 1, holes called construction holes are sometimes made in facilities formed by joining steel plates, such as large ships. Before the facility is completed, these construction holes are used as passageways for workers or components, and after the facility is completed, they are closed by welding. To close construction holes, the cut-off members that were cut off when the construction holes were formed are used. This is because the cut-off members fit the size of the construction holes.

[0003] Conventionally, drilling holes for drilling holes has been performed before joining steel plates, i.e., in specialized processing plants where steel plates can be leveled, while the steel plates are placed horizontally. This drilling process is performed using a highly efficient plasma cutting device. Figure 5 illustrates a conventional drilling method for drilling holes 55. In each of Figures 5(A)-(D), a plan view of the drilled hole 55 and its surroundings is shown at the top of the page, and a cross-sectional view of the centerline from the front is shown at the bottom of the page. As shown in Figure 5(A), when drilling a drill hole 55, e.g., a long hole, in a steel plate 50 to cut out a cutting element 51, a worker uses a plasma cutting device equipped with an NC (Central Control) to cut the hole into a predetermined shape. In this case, as shown in Figure 5(A), plasma cutting is performed with a tapered hole that becomes smaller from top to bottom. This tapered shape allows a welding groove to be created on the underside of the cutting element 51, i.e., on the side opposite the plasma cutting device. In addition, by tapering the hole so that it becomes smaller from top to bottom, the cut-out member 51 to be cut out can be prevented from dropping from the surface plate immediately after cutting, and the cut-out member 51 can be lifted by a lifting magnet or the like.

[0004] Next, as shown in FIG. 5(B), the cutting element 51 is removed from the steel plate 50 and stored in a location separate from the drilled hole 55. Then, as shown in FIG. 5(C), the hatched cutout portion 52 on the steel plate 50 side is cut by gas cutting, and a groove for welding is created on the underside of the steel plate 50. Cutting a position close to the initial cut path using a plasma cutting device would result in cutting a position close to the cut edge created during the initial cut, which would be unstable based on the principles of the plasma cutting machine. For this reason, in the past, a plasma cutting device could not be used to create the groove on the steel plate 50 side, and the groove was created by gas cutting. Then, as shown in FIG. 5(D), the steel plate 50 and the cutting element 51 are joined by welding so that the grooves on the steel plate 50 and the cutting element 51 face each other on the underside. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 08-197249 Summary of the Invention [Problem to be solved by the invention]

[0006] However, compared to cutting with a plasma cutting device, gas cutting takes time and places a heavy burden on the worker because it is done manually. In particular, in large facilities, dozens to hundreds of drill holes must be drilled, and the time and labor required for this cutting process increase the overall cost.

[0007] In view of the above circumstances, the present invention aims to provide a cutting and welding method for cut-off members that can replace gas cutting with cutting using a plasma cutting device, thereby reducing time and work load. [Means for solving the problem]

[0008] The cutting and welding method for a cutting element of the first invention comprises a cutting process in which a cutting element is cut from a steel plate using a plasma cutting device, and a welding process in which the cutting element is welded to the steel plate at the position where the cutting element was located and the hole that was there was closed; the cutting process comprises a first cutting process in which the plasma cutting device creates a groove on either the steel plate side or the cutting element side of the removed portion between the cutting element and the steel plate, either on the side where the plasma cutting device is located or the opposite side; and a second cutting process in which the plasma cutting device creates a groove on the other of the steel plate side or the cutting element side of the removed portion, either on the side where the plasma cutting device is located or the opposite side; and the welding process is characterized in that the cutting element is welded to the steel plate in a position flipped over in the thickness direction of the steel plate from the position where the cutting element was located. The method for cutting and welding a cut-off member of the second invention is characterized in that, in the first invention, in the first cutting step, the plasma cutting device creates a groove on the steel plate side of the removal portion between the cut-off member and the steel plate, opposite the side where the plasma cutting device is located, and in the second cutting step, the plasma cutting device creates a groove on the cut-off member side of the removal portion, on the side where the plasma cutting device is located. The third invention is a method for cutting and welding a cutting member, which is characterized in that, in the first invention, a fixing step is provided after the cutting step and before the welding step, in which the cutting member is fixed in the steel plate near the hole where the cutting member was located. [Effects of the Invention]

[0009] According to the first invention, the cutting process comprises a first cutting process in which a groove is made on either side of the thickness direction of the steel plate, and a second cutting process in which a groove is made on the other side. By turning the cutting member upside down and welding it in the welding process, the grooves that need to be made in the steel plate and the cutting member can be made using a plasma cutting device, thereby eliminating the gas cutting work that was performed in the cutting process and reducing the time and load required for making the grooves. According to the second invention, in the first cutting process, a groove is made on the steel plate side of the removed portion, opposite the side where the plasma cutting device is located, and in the second cutting process, a groove is made on the cutting member side of the removed portion, on the side where the plasma cutting device is located, thereby suppressing errors in end face detection by the plasma cutting device and further reducing the processing time and load. According to the third invention, a process for fixing the cutting member is provided after the cutting process and before the welding process, thereby preventing the cutting member that fits the opened hole from being lost and improving work efficiency. [Brief explanation of the drawings]

[0010] [Figure 1]1A and 1B are explanatory diagrams of a cutting and welding method for a cutting member according to a first embodiment of the present invention, in which Fig. 1A is an explanatory diagram of a first cutting step, Fig. 1B is an explanatory diagram of a second cutting step, Fig. 1C is an explanatory diagram of a state in which the cutting member has been removed, and Fig. 1D is an explanatory diagram of a welding step. [Figure 2] 1 is an explanatory diagram of equipment to which a cutting member cutting and welding method according to a first embodiment of the present invention is applied. [Figure 3] 1(D) is an enlarged cross-sectional view of the steel plate and the groove portion of the cutting member as viewed from the front. FIG. [Figure 4] 4A and 4B are explanatory diagrams of a cutting and welding method for a cutting member according to a second embodiment of the present invention. Fig. 4A is an explanatory diagram of a first cutting step, Fig. 4B is an explanatory diagram of a second cutting step, Fig. 4C is an explanatory diagram of a state in which the cutting member has been removed, and Fig. 4D is an explanatory diagram of a welding step. [Figure 5] 5A and 5B are explanatory diagrams of a conventional cutting and welding method for a cutting member. Fig. 5A is an explanatory diagram of the plasma cutting process, Fig. 5B is an explanatory diagram of the state after the cutting member is removed, Fig. 5C is an explanatory diagram of the gas cutting process, and Fig. 5D is an explanatory diagram of the welding process. DETAILED DESCRIPTION OF THE INVENTION

[0011] Next, embodiments of the present invention will be described with reference to the drawings. However, the embodiments shown below are merely examples of methods for cutting and welding a cutting member to embody the technical concept of the present invention, and the present invention does not limit the cutting and welding methods for a cutting member to those described below. Note that the size or positional relationship of the components shown in each drawing may be exaggerated for clarity of explanation.

[0012] FIG. 2 is an explanatory diagram of equipment 10 to which a method for cutting and welding a cutting member according to a first embodiment of the present invention is applied. This equipment 10 constitutes part of a large facility such as a ship, and is assembled unit by unit before the entire facility is assembled. The equipment 10 is formed by welding together a plurality of steel plates 20 by a worker 11. Some of this equipment 10 has holes called construction holes 25. Before the large facility is completed, the construction holes 25 are used as passageways for the worker 11 or as passageways for assembly components, and after the large facility is completed, they are closed by welding using a cutting member 21.

[0013] The holes 25 are formed by cutting before the equipment 10 is completed, i.e., before the steel plates 20 are welded together. The holes 25 are formed with the steel plates 20 facing up and down, i.e., with the steel plates 20 positioned horizontally. The holes 25 are preferably formed using a plasma cutting device, as this has higher work efficiency than other cutting methods. The plasma cutting device is composed of a gate-shaped moving device that straddles the steel plates 20, and a plasma cutting torch that is attached to the gate-shaped beam and moves in the axial direction of the beam. This plasma cutting device is usually controlled by NC.

[0014] (First embodiment) FIG. 1 shows an explanatory diagram of a cutting and welding method for a cutting member according to a first embodiment of the present invention. FIG. 1(A) is an explanatory diagram of a first cutting step, FIG. 1(B) is an explanatory diagram of a second cutting step, FIG. 1(C) is an explanatory diagram of a state in which the cutting member 21 has been removed, and FIG. 1(D) is an explanatory diagram of a welding step. In each of FIGS. 1(A) to 1(D), a plan view of the area around the drilled hole 25 is shown at the top of the page, and a cross-sectional view of the centerline from the front is shown at the bottom of the page. In addition, in all of the figures, the plasma cutting device is located above the steel plate 20, i.e., at the top of the front view of each figure.

[0015] The cutting and welding method for the cutting member 21 in this embodiment includes a cutting process in which the cutting member 21 is cut from the steel plate 20 using a plasma cutting device, and a welding process in which the cutting member 21 is welded to the position of the steel plate 20 where the cutting member 21 was located, and the hole that was provided therein is closed. The cutting process includes a first cutting process (Figure 1(A)) in which a plasma cutting device creates a groove on either the steel plate 20 side or the cutting member 21 side of the removal portion 22 between the cutting member 21 and the steel plate 20, either on the side where the plasma cutting device is located or on the opposite side, and a second cutting process (Figure 1(B)) in which a plasma cutting device creates a groove on the other of the steel plate 20 side or the cutting member 21 side of the removal portion 22, either on the side where the plasma cutting device is located or on the opposite side. In the welding process, the cutting member 21 is welded to the steel plate 20 in a position where the cutting member 21 is turned over in the thickness direction of the steel plate 20 from the position where the cutting member 21 was present (FIG. 1(D)).

[0016] In particular, in this embodiment, in the first cutting step, a plasma cutting device creates a groove on the steel plate 20 side of the removal portion 22 between the cutting member 21 and the steel plate 20, opposite the side where the plasma device is located, and in the second cutting step, a plasma cutting device creates a groove on the cutting member 21 side of the removal portion 22, opposite the side where the plasma cutting device is located.

[0017] As shown in FIG. 1(A), a worker 11 performs a first cutting step. That is, the worker 11 uses a plasma cutting device to cut a horizontally positioned steel plate 20 to remove a cutting member 21. The cutting member 21 at this time includes a removal portion 22 that will be separated from the cutting member 21 in a second cutting step described later. In this embodiment, the shape of the cutting member 21 is an elongated hole, i.e., a shape formed by connecting two semicircles with a straight line. However, this shape is not particularly limited. For example, the cutting member 21 may be circular or elliptical. During cutting, the plasma cutting device cuts the steel plate 20 side of the removal portion 22 shown in FIG. 1(B). At this time, the plasma cutting device controls the direction of its torch to cut the steel plate 20 so as to form a tapered edge that widens from the top surface to the bottom surface. The tapered edge that widens from the top surface to the bottom surface becomes a welding groove on the bottom side of the steel plate 20, opposite the top side where the plasma cutting device is located. The cutting in the first cutting step is not a full-circumference cut, but rather a portion of the cutout remains, maintaining the joined state between the steel plate 20 and the cutting member 21. It is preferable that these remaining portions are provided, for example, one each at the top and bottom of the plane of the plan view of Fig. 1(A).

[0018] Next, the worker 11 performs the second cutting step as shown in FIG. 1(B). That is, the worker 11 cuts the steel plate 20, which is placed horizontally, using a plasma cutting device to separate the cutting member 21 and the portion to be removed 22. At this time, the cutting is performed so as to create a groove on the cutting member 21 side of the portion to be removed 22, on the side where the plasma cutting device is located, i.e., on the upper side of the cutting member 21. Note that the cutting in the second cutting step is not a full-circumference cut, but rather a portion remains, so that the portion to be removed 22 and the cutting member 21 remain connected. It is preferable that these remaining portions are provided, for example, one on each of the top and bottom of the plane of the plan view of FIG. 1(B).

[0019] Next, as shown in FIG. 1(C), worker 11 cuts out cutting element 21 from steel plate 20 and creates drilled hole 25. At this time, the remaining portion between steel plate 20 and removed portion 22, and the remaining portion between removed portion 22 and cutting element 21, are cut by gas cutting. Then, as shown in FIG. 2, after the cutting process and before the welding process described later, worker 11 preferably performs a fixing process in which the removed cutting element 21 is fixed by welding to the vicinity of the drilled hole 25 in steel plate 20 where cutting element 21 was located. Here, "vicinity" is not particularly limited as long as it is close to the hole where cutting element 21 was located, as shown in FIG. 2. However, it is preferable that the cutting element 21 be located close enough to be visible together with the hole where cutting element 21 was located, specifically within 3 m. The process shown in FIG. 1(C) is preferably performed when steel plate 20 is in the state where it is installed as equipment 10.

[0020] By providing a process for fixing the cutting member 21 after the cutting process and before the welding process, it is possible to prevent the cutting member 21 that fits the opened hole from being lost, and to improve work efficiency.

[0021] Finally, as shown in Fig. 1(D), after the large-scale equipment is completed, the worker 11 performs a welding process in which the cutting member 21 is welded to the position of the steel plate 20 where the cutting member 21 was located, thereby closing the hole that was provided. At this time, the cutting member 21 is welded in a position that is flipped over in the thickness direction of the steel plate 20 from the position where the cutting member 21 was located relative to the steel plate 20.

[0022] 3 shows an enlarged cross-sectional view of the groove portion of the steel plate 20 and the cutting member 21 as seen from the front in the welding process of FIG. 1(D). In this embodiment, the innermost distance d1 of the steel plate 20 is greater than the outermost distance d2 of the cutting member 21. This configuration allows the cutting member 21 to easily pass through the drilled hole 25 formed in the steel plate 20.

[0023] The cutting process comprises a first cutting process in which a groove is made on either side of the thickness direction of the steel plate 20, and a second cutting process in which a groove is made on either side. By turning the cutting member 21 upside down and welding it in the welding process, the grooves that need to be made in the steel plate 20 and the cutting member 21 can be made using a plasma cutting device, which eliminates the gas cutting work that was performed in the cutting process and reduces the time and load required for making the grooves.

[0024] In the first cutting process, a groove is made on the steel plate 20 side of the removed portion 22, opposite the side where the plasma cutting device is located, and in the second cutting process, a groove is made on the cutting member 21 side of the removed portion 22, on the side where the plasma cutting device is located, thereby suppressing errors in end face detection by the plasma cutting device and further reducing the processing time and load.

[0025] When the arc in a plasma cutting device is tilted so that a steel plate 20 or the like is tapered, the cross-section of the member on the opposite side to the tilted side becomes an acute angle, and the tip of the acute angle falls off, increasing the possibility of an error in edge detection. By performing the first cutting process and the second cutting process as described above, the edge of the cut-out member side 21 of the removed portion 22 in the second cutting process becomes an obtuse angle, thereby suppressing errors in edge detection in the plasma cutting device.

[0026] (Second embodiment) FIG. 4 illustrates an explanatory diagram of a cutting and welding method for a cutting element according to a second embodiment of the present invention. FIG. 4(A) illustrates the first cutting step, FIG. 4(B) illustrates the second cutting step, FIG. 4(C) illustrates the state after the cutting element 21 has been removed, and FIG. 4(D) illustrates the welding step. As with FIG. 1, in each of FIGS. 4(A)-(D), a plan view of the area around the drilled hole 25 is shown at the top of the page, and a cross-sectional view of the centerline from the front is shown at the bottom. In each of the drawings, the plasma cutting device is located above the steel plate 20, i.e., at the top of the front view of each drawing. Regarding the second embodiment, the same details as those in the first embodiment will be omitted, and only differences from the first embodiment will be described.

[0027] In this embodiment, in the first cutting step, a plasma cutting device creates a groove on the cutting member 21 side of the removal portion 22 between the cutting member 21 and the steel plate 20, opposite the side where the plasma cutting device is located, and in the second cutting step, a plasma cutting device creates a groove on the steel plate 20 side of the removal portion 22, on the side where the plasma cutting device is located.

[0028] As shown in FIG. 4(A), worker 11 performs the first cutting step. That is, worker 11 uses a plasma cutting device to cut steel plate 20, which is placed horizontally, so as to cut out cutting member 21. During cutting, the plasma cutting device cuts the cutting member 21 side of the portion 22 to be removed, as shown in FIG. 4(B). At this time, the plasma cutting device controls the direction of its torch to cut the steel plate 20 so as to form a taper that narrows from the top surface to the bottom surface. The taper that narrows from the top surface to the bottom surface becomes a welding groove on the cutting member 21 side on the side opposite to the side where the plasma cutting device is located, i.e., the bottom side.

[0029] Next, the worker 11 performs the second cutting step as shown in Fig. 4(B). That is, the worker 11 cuts the steel plate 20, which is placed horizontally, with a plasma cutting device so as to separate the steel plate 20 from the removed portion 22. At this time, the steel plate 20 side of the removed portion 22 is cut so as to create a groove on the side where the plasma cutting device is located, i.e., on the upper side of the steel plate 20.

[0030] Next, as shown in Figure 4(C), the worker 11 cuts out the cutting member 21 from the steel plate 20 and drills the hole 25. At this time, the remaining portion between the steel plate 20 and the removed portion 22, and the remaining portion between the removed portion 22 and the cutting member 21 are cut off by gas cutting.

[0031] Finally, as shown in Fig. 4(D), after the large-scale equipment is completed, the worker 11 performs a welding process in which the cutting member 21 is welded to the position of the steel plate 20 where the cutting member 21 was located, thereby closing the hole that was provided. At this time, the cutting member 21 is welded in a position flipped over in the thickness direction of the steel plate 20 from the position where the cutting member 21 was located relative to the steel plate 20. [Explanation of symbols]

[0032] 10 Equipment 11 Workers 20 steel plate 21 Cutting parts 22 Removal part 25 Construction Hole

Claims

1. a cutting step in which a cut-out member is cut out from the steel plate by a plasma cutting device; a welding step in which the cutting member is welded to the steel plate at the position where the cutting member was located, thereby closing the hole provided therein; The cutting step includes a first cutting step in which a groove is formed by the plasma cutting device on either the steel plate side or the cutting member side of the removed portion between the cutting member and the steel plate, on either the side where the plasma cutting device is present or the opposite side thereof; A second cutting process in which a groove is provided by the plasma cutting device on either the steel plate side or the cutting member side of the removed portion, on the side where the plasma cutting device is present or on the opposite side thereof, In the welding step, the cutting member is welded to the steel plate in a position where the cutting member is turned over in the thickness direction of the steel plate from the position where the cutting member was present relative to the steel plate. A method for cutting and welding a cutting member, comprising:

2. In the first cutting step, a groove is formed by the plasma cutting device on the steel plate side of the removed portion between the cutting member and the steel plate, on the side opposite to the side where the plasma cutting device is present; In the second cutting step, a groove is formed by the plasma cutting device on the cutting member side of the removed portion, on the side where the plasma cutting device is present.

2. The method for cutting and welding a cutting member according to claim 1.

3. After the cutting step and before the welding step, A fixing step is provided for fixing the cutting member to the steel plate in the vicinity of the hole where the cutting member was located.

2. The method for cutting and welding a cutting member according to claim 1.

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