JP3126791B2 - Butt joining method of plate material and jig used for the joining method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a butt-joining method of a plate material such as a steel strip, a thin plate or the like, which is joined by welding and joining by welding, and a jig used for the joining method.

[0002]

2. Description of the Related Art Conventionally, flash butt welding is generally used for joining butted end faces of hardened sheet materials such as steel strips and thin plates. In this flash butt welding, a large current is applied while the end faces of the sheet material are in contact with each other, and an electric spark (flash) is applied to the contact surface.
Is generated by heating and melting the end faces with the heat, and then suddenly applying a strong pressure to join the end faces.

[0003]

The object of the invention is to be Solved by the way, with a conventional flash-butt welding machine described above, the plate material W _a and W
_When welding is performed by butt-matching _b , as shown in FIG.
With abutting surface portion of the welding portion W _c, the heat affected zone W _D spreads to the outer peripheral portion of the welded portion W _c is formed. Since the heat-affected zone W _D is relatively large, there are various problems.

Further, for pressurizing at the time of flash butt welding of butt plate material W _a and W _b, requires a large jig rigidity, and as abutting surface is not displaced, perpendicular to the end face with respect to the longitudinal direction together it is necessary to cut, weld raised portion W _E is generated around the, there is a problem that the overlay may be an upper W _E becomes undercut to remove the like grinder.

[0005] Laser welding has been used to solve the problems caused by these flash butt welders. In this laser welding, the welded portion W _c
Of the heat affected zone W _D formed in the outer peripheral portion is extremely narrow Nari desirable, would be absolutely recess W _F occurs at the end of the laser welding as shown in FIG. 6, the recess W _F
Another problem is that the stress is concentrated on the surface and it is easy to break.

SUMMARY OF THE INVENTION An object of the present invention is to provide a butt-joining method of a plate material in which a concave portion is not formed at the end point of laser welding, which can perform good joining, and a jig used for the joining method. To provide.

[0007]

In order to achieve the above object, the first aspect of the present invention is to start laser welding from both ends of a butt line at a butt portion of an end face of a plate material and to reach a substantially center when laser welding is started. A butt joining method of a plate material, wherein the power of the laser beam is gradually reduced according to the laser welding speed.

According to a second aspect of the present invention, when performing laser welding from one end to the other end of the butting line in the butting portion of the end surface of the plate, the abutment plate to be brought into contact with the other end is fixed. A jig having a first notch groove for performing laser welding to a part of the backing plate, and a second notch capable of engaging with a backing plate having a thickness corresponding to a plate thickness of the plate material; A groove is formed above the first notch groove.

[0009]

According to the first aspect of the invention, when laser welding is started from both ends of the butting line at the butting portion of the end face of the plate material and almost reaches the center, the power of the laser beam is gradually increased in accordance with the laser welding speed. In this case, no recess is formed at the edge of the plate material, so that breakage from the welded portion is suppressed and good joining is performed.

According to the second aspect of the present invention, when performing laser welding from one end to the other end of the butting line at the butting portion of the end face of the plate material, the jig is provided with the abutment plate which is brought into contact with the other end. The laser welding is performed to a part of the backing plate. Next, since the concave portion is not formed at the edge of the plate material by removing the backing plate from the plate material, breakage from the welded portion is suppressed and good joining is performed.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

Referring to FIG. 4, the laser welding machine 1 has a work table 3. The work table 3 is formed in a gate shape and includes side frames 3R and 3L and an upper frame 3U. The upper frame 3U is formed with a groove 5 having a slight downward step at a substantially central portion in the X-axis direction. A notch 5G for the back shield gas is formed at the front of the groove 5.

A back shield gas introduction hole 7 is provided in the Y-axis direction, which is the front-rear direction of the groove 5 substantially at the center, and communicates with the notch 5G. On the front side of the upper frame 3U, a cutout 9 for positioning a plate material is formed extending in the left-right direction.

[0014] With the above structure, placed plate material W _a, such as strip or sheet, a W _b in the notch 9 formed on the upper frame 3U of the work table 3, the plate material W _a, W
_b with one end allowed to abut against the projecting portion 3T of, matching plate material W _a, the end faces of W _b in the notch 5G. Further, a plurality of plate members fixing arm 11 of a plate material W _a from above the left and right side of the upper frame 3U, by fixing the W _b, so that the plate material W _a, W _b is positioned and fixed on the work table 3 .

Above the work table 3, a main body frame 13 (only a part) of the laser welding machine 1 is provided. On the main body frame 13, a machining head 15 movable in the X-axis and Y-axis directions is provided. Is provided. The mechanism for moving the processing head 15 in the X-axis and Y-axis directions is performed by a well-known ball screw, rack, pinion, or the like, and detailed description is omitted.

A focusing lens (not shown) is provided in the processing head 15, and a laser nozzle 17 is provided at a tip (lower end) of the processing head 15.

[0017] With this configuration, a laser beam oscillated from a laser oscillator (not shown) is condensed by the condenser lens in the machining head 15, further, is irradiated from the laser nozzle 17 plate material W _a, the abutting faces of W _b This results in laser welding.

The plate material W _a, when performing laser welding on the butt surface of the W _b (welded portion), the laser nozzle 17 to the laser beam
Irradiates the seal gas from the welding part (upper surface)
To stabilize the atmosphere on the entry side, and the notch 5 also extends from the back shield gas introduction hole 7 to the penetration side (lower surface).
By supplying and filling the G with the shielding gas, the welding atmosphere is stabilized and the laser welding is performed.

[0019] As a result, the weld fusion zone (bead) and the heat affected small and almost without generating deformation of the weld, can join the abutting faces of the plate material W _a and W _a, simple post-treatment such as annealing By itself, the same shape as the base material and the same mechanical strength can be obtained. Furthermore, the plate material W _a at the time of welding,
W there is no need to provide an external force to _b, because hardly occurs even deformation after welding, it can be joined with the plate material W _a, jig with a simple plate fixing arm 11 enough to hold W _b.

The plate material W _a, when welding butt the end faces of W _b, as shown in Figure 1, the plate material W _a, W _b of the end faces W _G, after first butt W _H, for example, start Point A ₁
The laser welding is welded upward as indicated by an arrow in FIG. 1 from performing substantially to the central portion W _c. Then, Yotsute to be performed from the start point A ₂ of the laser welding to a substantially central portion W _c downward as indicated by an arrow in FIG. 1, since no recess is formed on the edge of the weld, rupture of the weld Is suppressed.

When laser welding is performed from the start A ₁ and A ₂ to reach the substantially central portion _Wc , the power of the laser beam is controlled in accordance with the laser welding speed, and for example, the power of the laser beam is gradually increased. By making it weaker, a concave portion is not formed in the central portion _Wc , and uniform laser welding is performed.

[0022] Therefore, when pulled in the longitudinal direction of the plate material W _a, W _b, it is possible to avoid breakage of the welded portion from the plate material W _a, a recess at the edge of the W _b is not formed,
The strength of the break depends on the strength of the base material, and good joining can be performed.

Further, in the embodiment in FIG. 1, the plate material W _a, it may be an end surface of W _b as performed allowed formed on the inclined surface, may be a surface which is bent further inclined surface.

The plate material W _a, when welding butt the end faces of W _b, as shown in FIG. 2, the plate material W _a, W _b of the end faces W _G,
For example, when laser welding is performed from the start point A1 at _one end after the butting of the _WH , the other end is contacted.
Is provided with a jig 21 so as to abut. Some caul plate 19 to the jig 21 first notched groove G ₁ for perform the laser welding is formed up (Fig. 2, A ₃ points past the point A ₂ in Fig. 3).

Further, on the upper part of the first notch groove G ₁ ,
Plate material W _a, groove G ₂ caul 19-out second notch can freely engage with a thickness corresponding to the thickness t of W _b a (t) is formed. Incidentally, while it in the second notched groove G ₂ is of course, it is larger than the groove G _1-out first notch.

[0026] With this configuration, the wear plate 19 and fixed brought engage the second notched groove G ₂ of the jig 21, so allowed to contact the backing plate 19 the plate material W _a, the other end of the W _b jig Set 21. In this state, to start the laser welding from the start point A _1, performs laser welding to the point A ₃ is part of a caul plate 19 past the point A _2. Then, the plate material W _a from the jig 21, remove the caul 19 with W _b.
Then, the plate material W _a, W _b point A ₂ moiety joined against plate 19 portion at the other end portion of the cutting or grinding or, or plate caul plate 19 and hit it with such a hammer W _a , by removing from the W _b, the plate material W _a and W
_b will be joined well.

[0027] Therefore, when pulled in the longitudinal direction of the plate W _a, W _b, the plate material W _a, since the recess to the edge of the W _b is not formed, it is possible to avoid breakage of the welds. Further, it is possible to readily allowed to contact the backing plate 19 by using a jig 21 of a simple mechanism plate W _a, the other end of the W _b.

[0028] FIG 2, even in the embodiment shown in FIG. 3, the plate material W _a, may be an end surface of W _b as performed allowed formed on the inclined surface, even further surface which is bent inclined surface I do not care.

The present invention is not limited to the above-described embodiment, but can be embodied in other forms by making appropriate changes.

[0030]

As will be understood from the above description of the embodiment, according to the first invention, laser welding is started from both ends of the butting line at the butting portion of the end face of the plate material and reaches almost the center. At this time, by gradually weakening the power of the laser beam in accordance with the laser welding speed, since no recess is formed at both ends of the plate, when the plate is pulled in the longitudinal direction, breakage from the welded portion is avoided. And good bonding can be achieved.

According to the second aspect of the present invention, it is possible to easily perform the laser welding by easily making the abutting plate, which is engaged with the notch groove of the jig having a simple structure, abut the other end of the plate material. Can,
Since no recess is formed at the edge of the plate, the same effect as that of the first invention can be obtained.

[Brief description of the drawings]

FIG. 1 is a plan view of a plate material of the first invention butted and welded.

FIG. 2 is a plan view of the plate material of the second invention butted and welded.

FIG. 3 is an enlarged perspective view of a jig viewed from the arrow III in FIG. 2;

FIG. 4 is a perspective view in which a part of a laser welding material according to an embodiment of the present invention is omitted.

FIG. 5 is a cross-sectional view showing a state in which plate materials are butted and welded by a conventional flash butt welding machine.

FIG. 6 is a plan view showing a state in which plate materials are butted and welded by a laser welding machine.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 laser welding machine 3 work table 5G notch 7 back shield gas introduction hole 9 notch 11 plate fixing arm 15 processing head 17 laser nozzle 19 backing plate 21 jig G ₁ first notch groove G ₂ second notched groove W _a, W _b plate material W _G, W _H end face W _c central portion

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B23K 26/00-26/20 B23K 37 / 04,37 / 06

Claims (2)

(57) [Claims] When the laser welding is started from both ends of a butt line at an abutting portion of an end face of a plate material and reaches a substantially central portion, the power of the laser beam is gradually reduced according to the laser welding speed. Characteristic butt joining method of plate material. 2. A jig for fixing an abutment plate to be brought into contact with the other end when performing laser welding from one end of the butting line to the other end of the butting portion of the end face of the plate material. A first notch groove for performing laser welding to a part of the backing plate, and a second notch groove engageable by a backing plate having a thickness corresponding to the plate thickness of the plate material, (1) A jig formed on an upper portion of a notch groove.