JP4786401B2 - Method for manufacturing butt-welded metal sheet - Google Patents

Description

  The present invention relates to a method of manufacturing a butt weld metal plate (tailored blank material) by laser butt welding of a metal thin plate, and more specifically, by laser butt welding a weld metal thin plate used for plastic working such as a press. The present invention relates to a method of manufacturing a butt weld metal plate.

  In recent years, the application of a technology for joining a plurality of metal plates in advance by laser welding and forming the metal plates into a desired shape by secondary processing by plastic processing such as press molding is becoming common for automobiles. . If different types or different thickness metal plates are joined before press molding (see, for example, Patent Document 1) and pressed as a single metal plate, there is an effect of promoting partial reinforcement and weight reduction of the product.

  The problem that arises during laser butt welding is the high condensing ability of the laser beam, so it is necessary to position and weld the thin plates that are in contact with each other very precisely at the end face, and the thin plate has an extremely narrow gap between the thin plates. It is in the point which only allows it to have. In order to obtain good weld seam quality, in principle the gap is only allowed to have a width of 0.05 to 0.08 mm. This means that both the thin plates are allowed only a deviation of 0.04 mm from the same straight line.

  Manufacture of dissimilar or different thickness metal plates (referred to as tailored blanks) is a welding torch along the butt line by arranging metal plates (hereinafter sometimes referred to as blank plates) on a jig or pallet. In many cases, welding is performed. For example, as shown in FIG. 7, a laser beam 14 is irradiated to a welding zone 16 from a laser torch 12 to a gap portion between the butt steel plates 10 and 11, and the laser torch is moved in the welding progress direction 15 along the butt line. Alternatively, the weld bead 13 is formed while the steel plate is moved in the welding progress direction 15 with respect to the fixed laser torch to obtain a tailored blank material.

  Thus, when manufacturing a tailored blank material, the blank board has already sheared the outer shape with a punching press or the like. For example, when manufacturing a tailored blank material by laser welding along the weld line 5 and the weld line 6 by joining three metal plates (blank plates) 1, 2 and 3 as shown in FIG. It is necessary to precisely shear the angle (θ) 4. Although the butt angle is not precise, a laser that improves the end face accuracy and improves the weldability by grinding the end faces before butt welding the pair of welded members in the welding process. A welding system has been proposed (see, for example, Patent Document 2).

  In addition, a method is also proposed in which a plurality of thin steel plates are butted together and fixed by tack welding, and the butt portion of the thin steel plate is coined in the fixed state to narrow the bead width, and then the butt portion is laser welded. However, this method requires coining and has a problem in improving productivity.

  When manufacturing tailored blanks with a butt angle (θ), if this butt angle is inaccurate, the butt gap is enlarged to a larger butt gap 7 as shown in FIG. 6 and laser welding is performed. Cannot be performed, and the welding quality is affected. In order to make the butt gap required for laser butt welding 0.08 mm or less, it is required that the accuracy of the butt angle be a blank plate within an error range of 0.005 to 0.01 degrees of the design value. It is difficult to achieve this industrially with the current technology, no matter what precision mold is used.

When a butt gap is generated in butt laser welding, in the conventional technique, it is necessary to fill the gap using, for example, a filler wire (see, for example, Patent Document 4). However, in that case, there is a problem that a filler wire supply device is required and the capital investment increases. When the gap amount fluctuation is large, it is necessary to change the supply speed of the filler wire accordingly, and the control mechanism is complicated including an automatic gap measuring device.
The present invention intends to provide a technique capable of easily performing laser welding even in a method of manufacturing a butt-welded metal plate in which three or more metal plates that are likely to generate a butt gap are welded.

  The blank plate, which is the material for tailored blanks, has the residual strain and residual stress generated during rolling and heat treatment entrapped in the interior to a greater or lesser extent, and this is used as a blank plate of the desired shape using a die-cutting press. However, at that time, the shape collapses due to the release of residual strain and residual stress.

  Therefore, even if it has a blank metal mold | die of what precision, a blank board cannot be manufactured stably with such a high precision. For this reason, a tailored blank material formed by butt welding three metal plates as shown in FIG. 1 or a tailored blank material formed by butt welding four metal plates as shown in FIG. Currently, it is manufactured with increased costs due to falling yields.

JP-A-5-57467 JP 2004-243393 A JP-A-6-238472 JP-A-5-50274

Therefore, in view of the present situation as described above, the present invention relates to the need for precise punching of a metal plate to be welded in a butt weld metal plate (tailored blank material) formed by butt welding three or more metal plates. Eliminate and industrially stably weld 3 or more metal plates without dropping yield, and the angle where the weld line of the first butt weld and the weld line of the next butt weld intersect is an acute butt angle θ. it is possible to produce a butt weld metal plate having, there is provided a method for producing a butt welding metal sheets (tailored blank).

As a means for solving such a problem, the present inventor, when manufacturing a butt weld metal plate formed by butt welding three or more metal plates, first butt welds two metal plates, perform cutting in butt welding metal plate, possible to butt the cut edge of the butt weld the metal plate was cut into the end face was cut in different third sheet metal plate is prepared by following butt welding Thus, the need for precise punching is eliminated, and the butt-welded metal plate having an acute butt angle θ where the angle between the weld line of the first butt weld and the weld line of the next butt weld is an industrially stable ( The present invention was completed by finding that a tailored blank material could be produced.

  The gist of the present invention is as follows.

(1) formed by laser butt welding three metal plates (1,2,3), in the manufacturing method of butt welding metal plate, abutting the end face of the two metal plates (1, 2), the butt portion After laser welding to produce a butt-welded metal plate (a1) , the butt-welded metal plate (a1) is cut by a cutting line across the butt-welded weld line (6) of the butt-welded metal plate (a1) ( 9) and the cutting end face of the butt-welded metal plate (a1), which has been cut, is applied to the end face of another metal plate (3) and the weld line (6) of the butt-welded metal plate (a1) The welding line is characterized in that the butting angle (θ) with the end face of the metal plate (3) is abutted so as to be an acute angle, and laser butt welding (17) is performed to form a welding line (5) at the butting portion. manufacture of butt welding metal plate having an acute butt angle θ Law.

( 2 ) In a method for producing a butt-welded metal plate formed by laser butt welding four metal plates (1 , 2, 3, 8), two metal plates (1, 2, and 3, 8) Each end face is butted and laser welding is performed on the butted portion to produce two butt welded metal plates (a2, a3), and then each weld line (butting welded on each of the butt welded metal plates (a2, a3)) ( 6a, 6b) is cut along the respective butt-welded metal plates (17) along the cutting line, and the cut end faces of the respective butt-welded metal plates (a2, a3) are cut into the respective butt-welded metal plates (a2, a3) . Butt and butt sections so that the butt angle (θ) between each weld line (6a, 6b) of the butt weld metal plate (a2, a3) and the end face of each butt weld metal plate (a2, a3) is an acute angle Dissolved in Characterized by butt laser welding to form a line (5) The method of butt welding the metal plate weld line has an acute butt angle theta.

(3) the butt welding metal plate making by laser welding the butted portion (a1, a2 or a3) is butt in parallel three or more metal plates, are butt-welded metal plate was laser welded butt portion A method for producing a butt-welded metal sheet, wherein the weld line according to (1) or (2) has an acute butt angle θ .

According to the present invention, when producing a butt weld metal plate (tailored blank material) having a butt angle θ formed by laser butt welding three or more metal plates, the precision of the butt weld metal plate (blank plate) is obtained. This eliminates the need for a punching process, and has a remarkable effect that it can be manufactured industrially stably.

Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing a manufacturing example of a butt-welded metal plate (hereinafter sometimes referred to as a tailored blank material) formed by butt welding three metal plates (blank plates).

  When a tailored blank material is manufactured by welding three metal plates (blank plates) 1, 2 and 3 as shown in FIG. (Θ) 4 needs to be sheared precisely. For example, when butt welding thin steel plates with different plate thicknesses, laser welding has a large bead width, so the change in the thickness of the welded portion is large. Stress concentrates in the vicinity, and cracks are likely to occur near the weld. Further, if the bead width is wide by laser welding, it is difficult for the laser beam to penetrate the thin steel plate to form a good bead even if the laser output is increased or the welding speed is decreased. Therefore, in order to obtain a butt welded thin steel sheet with good press formability, it is required to have an appropriate and accurate bead width.

  Normally, even if a butt-welded metal plate (steel plate blank plate) is punched out with a mold having sufficient accuracy, an error of about 0.1 degree in the maximum angle accuracy of the product at the time of steel plate blank is expected. If the variation in the butt angle is assumed to be a normal distribution and the required butt angle is 0.005 degrees, the probability of satisfying it is expected to be 0.12. As a tailored blank material consisting of three blanks welded in a state where the welding lines as shown in FIG. 1 cross, the butt angle of the metal plate 1 and the metal plate 2 cannot be established unless they are within the required butt accuracy range at the same time. The probability of a butt angle is 0.014. Therefore, the process yield is expected to be 1.4% when the already blanked metal plate is butted on the pallet at the same time and welding is performed along the butt line as in the prior art. It does not hold.

  Therefore, the present invention is to manufacture a butt welded metal plate by butt welding a metal plate once, then cutting the butt welded metal plate, and butt welding the end surface of the other metal plate cut. This eliminates the need for precise punching of the metal plates to be butt-joined, and makes it possible to produce a butt-welded metal plate (tailored blank) that is industrially stable and has good press formability.

  3-5 is a figure which shows the manufacturing procedure of the tailored blank material by this invention.

First, as shown in FIG. 3, the two metal plates 1 and 2 are butt welded along the weld line 6 to obtain a butt weld metal plate . Next, as shown in FIG. 4, the next welding planned line of the butt weld metal plate a1 (which becomes a welding line intersecting with the first welding line) is sheared (cut) 9 by a shearing device. When the shearing process is performed, the first (first) welding line 6 is included (crossed) in the cutting line at the time of the cutting process to form a butt end face with another metal plate. Next, as shown in FIG. 5, laser butt welding 17 is performed by butting the next third metal plate 3 blank material to the shear line of the butt- welded metal plate a <b> 1 subjected to the shearing process.

This makes it possible to manufacture tailored blanks with a butt angle (θ) as shown in Fig. 1 in an industrially stable manner, eliminating the need for precise punching of metal plates before welding. It becomes. Even if the butt angle of the third metal plate (blank plate) to be butt welded is not within the error range of 0.005 to 0.01 degrees of the design value, it is sheared once before performing welding ( By performing the cutting process, the straightness of the butt planned line can be made into a problem-free state, and even if the shape is somewhat inaccurate, the weld line 6 and the weld line 5 have a sharp angle butt without any quality problem. It is possible to manufacture a butt weld metal plate (tailored blank material) having an angle (θ) 4 .

Further, four metal plates in which two welding lines (6a, 6b) and a welding line 5 as shown in FIG. 2 exist at two acute butt angles (θ) 4 of less than 90 degrees are butt welded. When producing butt-welded metal plates ( tailored blanks ) , first, two metal plates 1 and 2 and metal plates 3 and 8 are first butt-welded separately, and then two butt-welded metal plates. (A2, a3) are produced . Next, in the same manner as in the case of the butt weld metal plate shown in FIG. 4, the welding line of each butt weld metal plate (a2, a3) butt welded is measured with a shearing device . a3) is sheared (cut). A butt end face is formed by including the weld line 5 made in advance in the cutting line during the cutting process. Next, the two butt-welded metal plates (a2, a3) are butt-welded at the planned welding line to be laser butt-welded to become the weld line 5 . By welding in such a welding procedure, a tailored blank material having two butting angles θ can be manufactured without performing precise punching of a metal plate before welding. Although two metal plates were first butt welded to produce a butt-welded metal plate (tailored blank semi-finished product) , three or more metals were used as required, although not shown if necessary. It is good also as a butt-welded metal plate (tailored blank semi-finished product) by carrying out butt welding first with a parallel plate. Thereby, the tailored blank material which butt-welded the some metal plate is obtained. Moreover, it becomes possible to manufacture a tailored blank material having a plurality of butt angles θ by repeatedly combining the manufacturing procedures described above with reference to FIG. 1 or FIG.

  The at least one metal plate used for producing the tailored blank material of the present invention is preferably a thin steel plate having a thickness of 2 mm or less, particularly 1 mm or less. And the thin steel plate which butt-welds can use the thin steel plate from which one or both of board thickness and intensity | strength differs. Moreover, when butt welding such a thin steel plate, it is suitable to weld by laser butt welding. That is, in other welding methods such as arc welding, the welding input becomes excessive, and when a thin steel plate is welded, a burn-out defect occurs. In particular, although it is difficult to manufacture a tailored blank material having an acute butt angle, according to the present invention, it can be easily manufactured.

The present invention will be described based on examples.
As shown in FIG. 1, the welding test which manufactures the butt-welded metal plate ( tailored blank material ) from which the plate | board thickness which has an acute butt angle ((theta)) from which thickness differs was implemented. The metal plate 1 subjected to the test is a mild steel plate having a thickness of 1.4 mm, the metal plate 2 is a mild steel plate having a thickness of 1.2 mm, and the metal plate 3 is a mild steel plate having a thickness of 1.0 mm. Using. The finished size of the total tailored blank was about 1 m × 1 m.

(Comparative example)
First, as a conventional technique, three metal plates each sheared in a blank process were arranged and butted on a flat surface plate, and clamped and fixed from the upper surface of the metal plate with an air cylinder. The weld line (butt angle theta: 80 degrees) which butt of three metal plates along the weld while irradiating a carbon dioxide gas laser (output 1.5 kw, welding speed 2.0 m / min) line have tailored blanks to The material was manufactured . In this way, 100 tailored blanks were manufactured and pressed. As a result of welding failure due to the butt gap, cracks in the welded part occurred during the press processing on 98 sheets, and only 2 non-defective products were produced. It was not possible to collect.

(Invention example)
On the other hand, by applying the technology of the present invention, first, the two metal plates 1 and 2 made into a blank are butt-laid on a flat surface plate, and first butt-welded with a carbon dioxide laser as in the prior art, a semifinished product of tailored blanks made of the metal plate 1 and 2, and the butt welding planned line of the metal plate 3 to butt welding this, shearing by the shearing device, the tailored blank made of a metal plate 1 and 2 The semifinished product was butted with a metal plate 3 at an acute butt angle (θ) 4 and butt welded with a carbon dioxide laser to produce a butt weld metal plate (tailored blank material) . When 100 sheets were manufactured in this way and pressed, only one sheet caused cracks in the welded part due to poor welding due to the butt gap, and 99 good products could be collected. It was.

By carrying out the shearing process once before carrying out the welding as in the present invention, the straightness of the butt welding planned line can be made into a problem-free state, and even a somewhat inaccurate shear shape has no problem in quality. It was possible to manufacture. In addition, the same effect can be obtained in the case of a butt-welded metal plate (tailored blank material) composed of four metal plates as shown in FIG. 2 to which the present invention technology is applied, and even if the number of metal plates is increased. It can be seen from the above test that similar effects can be obtained.

  The present invention is used for tailored blank materials for automobiles and the like, and in particular, as a tubular member having partially different strength and thickness by bending the tailored blank material into a tubular shape and welding it. Can be used.

It is a figure which shows the example of the tailored blank material formed by butt-welding three metal plates. It is a figure which shows the example of the tailored blank material formed by butt-welding four metal plates. It is a figure which shows the manufacture procedure of the tailored blank material which butt-welds two metal plates first. It is a figure which shows the manufacturing procedure of the tailored blank material which performs the shearing process after welding two metal plates. It is a figure which shows the manufacture procedure of the tailored blank material which welds the 3rd metal plate after a shearing process. It is a figure which shows the manufacture example of the tailored blank material which the problem of the inaccurate butting angle by a prior art produces. It is a figure which shows the laser butt welding process of a tailored blank material.

1 Metal plate 2 Metal plate 3 Metal plate 4 Butt angle (θ)
5 Welding Line 6 Welding Line 7 Large Butt Gap 8 Metal Plate 9 Shearing 10 Steel Plate 11 Steel Plate 12 Laser Torch 13 Weld Bead 14 Laser Beam 15 Welding Direction 16 Weld Zone
17 Welding
a1, a2, a3 Butt weld metal plate
6a, 6b Welding line

Claims (3)

Comprising three metal plates (1, 2, 3) by laser butt welding, in the manufacturing method of the butt welding metal plate, abutting the end face of the two metal plates (1, 2), the butted portion by laser welding After producing the butt weld metal plate (a1), the cutting process (9) of the butt weld metal plate (a1) is performed with a cutting line crossing the weld line (6) butt welded of the butt weld metal plate (a1). The cut end face of the butt-welded metal plate (a1), which has been performed and subsequently cut , is connected to the end face of another metal plate (3) , and the weld line (6) of the butt-welded metal plate (a1) and the other metal plate (3) Butt angle (θ) with the end face is an acute angle, and laser butt welding (17) is performed to form a weld line (5) at the butt portion. A method for manufacturing a butt-welded metal plate having an angle θ . In the method of manufacturing a butt-welded metal plate formed by laser butt welding four metal plates (1 , 2, 3, 8), the end surfaces of the two metal plates (1, 2, and 3, 8) each The butt welds are laser welded to produce two butt weld metal plates (a2, a3), and then the respective weld lines (6a, 6b) butt welded to the respective butt weld metal plates (a2, a3). The cutting process (17) of the respective butt-welded metal plate is performed at a cutting line crossing the butt-welded metal plate, and then the cut end faces of the respective butt-welded metal plates (a2, a3) that have been cut are used as the respective butt-welded metal sheets. Butt so that the butt angle (θ) between each weld line (6a, 6b) of plate (a2, a3) and the end face of each butt weld metal plate (a2, a3) is an acute angle, and the weld line at the butt portion (5 Characterized by butt laser welding to form a method for butt welding sheet metal welding wire has an acute butt angle theta. Wherein the butt welding metal plate abutting portion making by laser welding (a1, a2 or a3) is butt in parallel three or more metal plates are butt-welded metal plate having a laser welded butt portion method for producing a butt welding metal plate weld line has an acute butt angle θ according to claim 1 or 2,.

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