JPH05123878A - Butt laser beam welding method - Google Patents

Abstract

PURPOSE:To set a butt gap with high accuracy by inserting shims having thickness corresponding to the butt gap quantity into the shear-cut surfaces of materials to be welded. CONSTITUTION:In butt laser beam welding where a couple of metallic sheets 1 and 2 to be welded are subjected to butt welding with the specified gap quantity S, the metallic sheets 1 and 2 to be welded are shear-cut, then, the shims 5 having thickness corresponding to the gap quantity S are inserted into the shear-cut surfaces of both sheets in the vicinity of both ends thereof, both metallic sheets are abutted on each other via the shims 5 and then, subjected to laser beam welding. After welding, the remaining sheet ends of the shims are then cut and removed. Consequently, the butt gap quantity can be obtained with high accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a butt laser welding method for thin metal sheet materials, and more particularly to a butt laser welding method suitable for continuously passing a metal strip in a process line.

[0002]

2. Description of the Related Art Butt laser welding is performed from a leading plate and a trailing plate as described in Japanese Patent Publication No. 61-1236, Japanese Patent Publication No. 2-1608 or Japanese Patent Publication No. 64-87090. Butt welding of a pair of materials to be welded, the butt precision is extremely important for obtaining a suitable bead shape and preventing cracks from occurring in the welded portion. As shown in FIG. If the butt gap S with the row plate 2 is too large, it becomes a concave bead 6, and if the butt gap S is too small, it becomes a convex bead 7, both of which reduce the welding strength.

Therefore, in order to improve the accuracy of the butt gap amount between the materials to be welded, the following method devices have been conventionally proposed. Japanese Examined Patent Publication No. 2-1608 includes a pair of upper blades and lower blades for shearing a pair of welded plates used for butt laser welding and a combination of a straight blade and a raked blade. For the guillotine cut type shearing machine, the rake angle tan α of the blade with the rake angle is set to tan α ≤ (35 + 2.5t) / 1000 t: the thickness of the welded plate (mm) to improve the cutting accuracy. A method for improving the cut end face shape has been proposed.

However, the accuracy of the butt gap amount does not depend only on the rake angle of the shearing machine blade,
The clearance of the upper and lower shear blades, the levelness of the clamping device on both the input and output sides, and the stop position accuracy of the moving clamper, as will be described later, greatly depend on this method to increase and maintain the accuracy of the butt gap amount. It is difficult. Also,
Japanese Patent Laid-Open No. 53-2362 discloses a method of welding a pair of members to be welded which are arranged with a necessary gap, in which the end face of one of the members to be welded is located inside the minimum penetration portion by welding. Crush a part or all, project a part or all of the end surface of the member to be welded as a protrusion by the width of the gap required for the butting, and abut the end face of the other member to be welded facing each other, A butt welding method is disclosed in which a pair of members to be welded facing each other with the projection of the member to be welded in between are butt-welded to each other.

However, in order to form the protrusion,
Changing the length and thickness of these protrusions according to the thickness of the thin steel plates to be welded to each other requires a press machine, etc. The structure and control become complicated, and the equipment cost must be expensive. Further, in Japanese Utility Model Laid-Open No. 57-106579, in a connecting device in which strip ends are respectively cut and then butt welded to each other, a forward end of a clamping device that is movable in the longitudinal direction of the strip line and abuts the strip ends with each other. Disclosed is a metal strip connecting device in which the reverse ends are regulated by stoppers fixed to the base.

However, in this device, the abutting gap amount is changed due to wear of the stopper, wear of the collision member of the movable clamp device that collides with the stopper, deterioration of the play of the clamp moving guide, and deterioration of left-right balance. Therefore, not only the gap amount needs to be adjusted frequently, but it is difficult to change the gap amount according to the thickness of the strip.

Further, Japanese Patent Laid-Open No. 61-176489 discloses a first clamper for fixing the rear end of a leading strip,
Has a first clamper arranged to face the other clamper for fixing and moving the leading end of the trailing strip, and the shringing for trimming the trailing end of the leading strip and the leading end of the trailing strip in both the clampers. The device is configured to give a predetermined rigidity to a stopper device that determines the stop position of the second clamper mechanism that moves and abuts the trailing strip with respect to the shear cutting line of the preceding strip so that the stopper device can be displaced reversibly. There is disclosed a strip connecting device having an indexing mechanism for arbitrarily setting the abutting amount and a device for laser beam welding after abutting the strips.

However, in this technique, the stopper device that determines the forward stop position of the moving clamper mechanism is given a predetermined rigidity so that the stopper device can be displaced so as to be restored, and the butt gap amount is arbitrarily set. 57-10657
It is superior to the device disclosed in No. 9 publication. However, the gap value after the butting is measured, and when this gap value is not set to the optimum value, the pressure is adjusted by the pressure regulating valve to change the output of the cylinder for moving the clamper, and the output of this cylinder and the predetermined rigidity are changed. The butt gap is corrected to an optimum value by utilizing the mutual relationship with the bending characteristics of the stopper having There is a problem in performing such gap measurement and adjustment of the pressure regulating valve manually, from the viewpoint of time loss and labor saving, and in the case of automatic setting, the gap automatic measurement point and measurement accuracy are laser This is a big problem in comparison with the small required butt gap value in the case of beam welding (in the case of laser beam welding of a thin plate, it needs to be a small value of, for example, 20 to 50 μm).

Further, in Japanese Patent Laid-Open No. 51-95950, a welding machine for a steel process line is provided with an eccentric mechanism (shaft) on a movable clamper which holds a strip cut by a shear. ) Is rotated to move the clamper to obtain a butt gap required for welding, and a strip butt gap adjusting device is disclosed.

However, in this device, the eccentric mechanism is used.
The stopping accuracy of the (axis) rotary drive actuator greatly affects the accuracy of the butt spacing, and there is a problem when the required gap amount is small and the required gap accuracy is strict as in laser beam welding of thin plates. If only one space adjustment device is provided in the plate width direction, the gap amount in the plate width direction may differ due to wear or looseness of the device, and if two gap adjustment devices are provided at both ends in the plate width direction, In addition to wear of the devices on both sides and unbalance of the backlash, it is necessary to accurately synchronize the rotary actuators, and there is a great possibility that the gap amount in the plate width direction also varies.

Further, Japanese Laid-Open Patent Publication No. 64-87090 discloses a method of butt welding thin plate members and irradiating a laser beam along the butt end faces to perform butt welding. A butt-welding method using a laser beam in which a gap is formed between the butt end faces, and the dent has a bay shape in which both ends project and the middle part recedes, and the both ends are pressure-welded between welding members. And further, the dent penetrates through the entire plate thickness, and such a dent appears repeatedly in the longitudinal direction of the butt end face, and further the dent appears in a part of the total plate thickness, Further, there is disclosed a butt-matching method using a laser beam, which is made to appear repeatedly in the longitudinal direction of the butt-end faces.

However, in this method, the shape of a cutting tool such as a shear or a punching press has to be complicatedly processed in order to form a recess on one side of the thin plate with a small number of butt end surfaces, and it is necessary to adjust and set with high precision. When it becomes necessary to change the depth and shape of the dent due to changes in the thickness of the plate material,
There is a problem that a cutting tool needs to be replaced, and a device for exchanging the cutting tool or time is required for replacement. Further, if the welding conditions are not properly selected because the depths of the recesses are different in the plate width direction or the recesses are discontinuous, the shape of the weld bead may be adversely affected.

[0013]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned drawbacks of the conventional butt laser welding method and apparatus,
An object of the present invention is to provide a butt laser welding method in which the butt gap amount can be easily and accurately set to a predetermined value, and therefore a good bead shape can be obtained and welding defects are less likely to occur.

[0014]

That is, according to the present invention, there is provided a butt laser welding method for butt-welding a pair of thin metal sheet materials to be welded with a predetermined gap amount S, in which a preceding plate
Two pieces of welded material are shear cut, and shims having a thickness corresponding to a predetermined gap amount S are inserted between the shear cut surfaces of the welded material and in the vicinity of both ends of the shim cut surfaces. Laser welding after abutting the material through the shim, a butt laser welding method characterized by cutting and removing the remaining plate end of the shim with a notcher, in particular, the present invention, hot rolled steel strip Suitable for continuous pickling in the process line and welding during continuous cold rolling.

[0015]

[Operation] According to the present invention, a shim having a thickness corresponding to a predetermined gap amount is inserted into both ends of a material to be welded having a narrow plate width, and a pair of ends of the material to be welded are abutted through the shims. Therefore, regardless of the rake angle of the shear blade, the clearance of the upper and lower shear blades, the forward and backward movements of the movable clamp device, the wear and backlash of the retraction mechanism, and the accuracy of the backward stop position, and without the need to measure the gap amount. It is possible to easily and surely obtain the predetermined amount of butt gap with high accuracy. Further, according to the present invention, the butt gap amount can be easily changed in accordance with the change in the plate thickness of the material to be welded, only by changing the thickness of the insertion shim.

Further, according to the present invention, after laser welding is completed,
Since the non-welded portion or the defective welding portion at both ends of the thin plate material where the shim remains is cut and removed by a notcher, there is no possibility of causing a weld portion rupture in the process line threading due to the both ends of the thin plate material.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the essential part of the implementation status of an embodiment of the method of the present invention. (a) is a plan view when the shim is inserted, (b) is a side view when the shim is inserted, and (c) is a plan view of a cutting state by notching of both ends of the thin plate where the shim remains after welding. In the drawing, 1 is a leading metal strip, 2 is a trailing metal strip, 3 is a fixed clamp device on the outgoing side, 4 is a movable clamp device on the incoming side, 5 is a shim having a thickness S, and a range indicated by a diagonal line 8 is cutting by notching. The removed part is shown.

A pair of preceding steel strips 1 (plate thickness 4.0 mm, plate width 1200 m
m) and trailing steel strip 2 (thickness 3.5 mm, width 1400 mm) after shear cutting SPCC (JIS G3141 pickled hot rolled steel strip for general low carbon cold rolled steel sheet) , At the end of the narrow plate (in this case, the preceding steel strip 1),
A preceding steel strip 1 in which a shim 5 having a width of 20 mm and a height of 20 mm with a predetermined butt gap amount S = 0.2 mm is inserted and clamped by the movable clamp 4 on the input side, and then the steel strip 2 is fixed by the fixed clamp on the output side. I pushed it towards. After this, laser welding of the area of the central portion W of the steel strip avoiding the 20 mm wide portion of the shim 5 is performed, and then both end portions including the unwelded portions of the shim 5 and the steel strips 1 and 2 are cut by a notcher (not shown). Was cut off.

The laser welding conditions at this time were as follows. Laser output: 9 kw Butt gap: 0.2 mm Filler wire diameter: φ1.2 mm Filler feed speed: 7 m / min Welding speed: 4 m / min Then, the above steel strip was rolled to 1.0 mm by a cold rolling mill. It was possible to roll stably without breaking at the weld. In a process line for processing a thin steel strip having a plate thickness of 1.0 mm or less or a metal strip softer than steel, buckling of the strip may occur due to the method of the present invention. Care must be taken when selecting the pressing force.
In that sense, it is desirable to apply the present invention to butt laser welding of a metal strip having a large plate thickness before pickling or cold rolling.

[0020]

EFFECTS OF THE INVENTION According to the present invention, the quality of the welded portion of butt laser welding is improved, and a great productivity improving effect is achieved by reducing plate breakage in a continuous processing process line such as cold rolling or pickling of metal strip. Was obtained. Further, the adjustment frequency of the device for coping with the variation of the butt gap due to wear of the movable clamp device of the butt laser welding device and the positioning stopper device for stopping the forward / backward end of the butt laser welding device has been drastically reduced.

[Brief description of drawings]

FIG. 1 is an explanatory view of essential parts of an embodiment of a butt laser welding method of the present invention.

FIG. 2 is a schematic diagram showing defective welding.

[Explanation of symbols]

 1 Leading metal strip 2 Trailing metal strip 3 Outlet side fixed clamp device 4 Inlet side movable clamp device 5 Shim 6 Recessed bead 7 Convex bead 8 Removal part by notching W Welding range S Butt gap amount

Claims (2)

[Claims] 1. In a butt laser welding method of butt-welding a pair of thin metal sheet materials to be welded with a predetermined gap amount S, shearing is performed on two to-be-welded materials of a preceding plate and a trailing plate, and then a predetermined amount. A shim having a thickness corresponding to the gap amount S is inserted between the shear cut surfaces of the material to be welded and in the vicinity of both ends thereof, two pieces of the material to be welded are abutted via the shim, and then laser welded, so that the shim A butt laser welding method characterized by cutting and removing the remaining plate edges with a notcher. 2. The butt laser welding method according to claim 1, wherein the pair of thin metal sheet materials to be welded are hot rolled steel strips.