JP2009248104A - Weld bead shaping method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a weld bead shaping method having a wide application area and excellent workability. <P>SOLUTION: In the weld bead shaping method, a weld bead is flattened by irradiating it with a laser beam for fusing. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a weld bead shaping method.

As is well known, in welding joining such as arc welding or laser welding, a weld bead (a weld mark formed by solidification of molten metal) is formed along the weld line. The shape (surface shape) of this weld bead is generally known as indicating welding quality. In Patent Document 1, the uneven concentration of the weld bead formed by fillet welding is flattened to obtain stress concentration. It is disclosed that the reduction of the fatigue strength of fillet beads due to the above is suppressed. Further, in Patent Document 1, as a specific method of shaping the weld bead flat, frictional heat is generated by pressing and moving the fillet material against the surface of the fillet bead. It is disclosed that the surface of the fillet bead is planarized by melting a portion of the braid and fillet bead.
JP 2002-263836 A

  However, in the above conventional shaping method, a member (base material) on which a fillet bead is formed is fixed on a slide base, and this slide base is pressed against a cylindrical meat filling material using a pressure cylinder. Since the member (base material) is moved while rotating the meat material, the applicable members are considerably limited. In other words, it can be applied to a member that can be placed and fixed on a slide table such as a welded part of a component, but a fixed structure such as a building must be mounted and fixed on a slide table. Therefore, the conventional shaping method cannot be substantially applied to the welded portion of the fixed structure.

  Further, since the conventional shaping method is to melt part of the fillet material and fillet bead by frictional heat, it is necessary to press the fillet material on the member on which the fillet bead is formed with a relatively large load. Therefore, there is also a problem that it can be applied only to a member having mechanical strength that can withstand such a relatively large load.

  Furthermore, since the conventional shaping method moves the member on which the fillet bead is formed in a state where the meat filling material is pressed, it is necessary to sufficiently adjust the positional relationship between the meat filling material and the member, Therefore, there is a problem that the workability of shaping is poor.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a weld bead shaping method having a wide application range and good workability.

In order to achieve the above object, in the present invention, as a first solving means, means for flattening is performed by irradiating a welding bead with a laser beam and melting it.
As a second solving means, a means is adopted in which the spot diameter of the laser beam is set to the width of the weld bead in the first means.
As a third solving means, a means is adopted in which the first or second means is applied to a weld bead of a T-joint that is laser-welded.

According to the present invention, since the laser beam is irradiated to the weld bead and melted, the surface is flattened, so that there is no need for a special mechanism for fixing and moving the member on which the weld bead is formed as in the prior art. It can be applied to a wide range of welds.
In particular, in the case of a welded part of a building, it is practically impossible to place and fix it on a slide base as in the prior art, but according to the present invention, the welded part is placed on a slide base. Since it is not necessary to mount and fix, it can be applied to welded parts of buildings.
Moreover, when shaping the welding bead extending linearly, the work position is extremely good because the irradiation position of the laser beam may be moved along the welding bead.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing a weld bead shaping method according to the present embodiment. This figure shows a case where a welding bead (filled bead B2) of a T-shaped joint W in which a rib is fillet welded to a flat base material by a laser welding apparatus is used as a shaping control. This T-shaped joint W is welded and joined by irradiating a laser beam R from the fillet bead B1 side of the rib to the butted portion of the rib and the base material.

  In the T-shaped joint W formed in this way, the fillet bead B2 on the side opposite to the side irradiated with the laser light R has a shape in which the vicinity of the center is raised as shown in the figure. Such a raised portion in the fillet bead B2 is not preferable because the fatigue strength of the T-shaped joint W is lowered, and it is necessary to flatten it by shaping as shown by a one-dot chain line.

  In the present weld bead shaping method, high-energy laser light R emitted from the laser oscillator 1 is supplied to the laser irradiation device 2 via the appropriate optical transmission path for the fillet bead B2, and the laser A laser beam R for shaping is irradiated from the irradiation device 2. The laser oscillator 1 is a carbon dioxide gas laser or a YAG (yttrium, aluminum, garnet) laser used in the laser welding apparatus. In addition, the laser irradiation device 2 irradiates the fillet bead B2 with the laser beam R incident from the laser oscillator 1 through the optical transmission path being narrowed to a predetermined spot diameter.

  FIG. 2 is a schematic view of the T-shaped joint W as viewed from the upper side in FIG. 1. The laser irradiation device 2 is configured to be movable in a direction parallel to the fillet bead B2 extending linearly. Yes. Such a laser irradiation apparatus 2 irradiates the fillet bead B2 with the laser beam R while moving at a constant moving speed from one end (the lower end in FIG. 2) to the other end (the upper end) of the T-shaped joint W.

  The spot diameter is set in accordance with the width of the fillet bead B2, that is, the dimension T. Thereby, in this embodiment, substantially the entire surface of fillet bead B2 can be melted in a cross section orthogonal to the extending direction of fillet bead B2.

Next, a specific procedure of the present weld bead shaping method will be described in detail with reference to FIGS.
Initially, shaping preparation is performed. In the shaping preparation step, the laser irradiation device 2 is initially set at one end (the lower end in FIG. 2) of the T-shaped joint W, and in this state, the optical axis and the spot diameter of the laser light R are finished. Set the direction and dimension T of the meat bead B2. Such a shaping preparation step is performed manually by an operator in consideration of the positional relationship between the T-shaped joint W and the laser irradiation device 2. In this shaping preparation step, the fillet bead B2 is irradiated with the laser beam R because it is necessary to adjust the optical axis and the spot diameter, but the laser beam R at this time is a low energy for preparation that cannot melt the fillet bead B2. Light.

  When the shaping preparation process is completed, the operator inputs a shaping start command to the laser irradiation device 2 so that the main irradiation of the laser beam R to the fillet bead B2 and the extending direction of the fillet bead B2 are performed. The movement at a constant movement speed along the line is started.

  Here, since the energy of the laser beam R in the main irradiation is constant, the moving speed defines the amount of heat input to the fillet bead B2, that is, the melting depth of the fillet bead B2. Since the melt depth of the fillet bead B2 differs depending on the material of the T-type joint W, the operator designates a different moving speed depending on the material of the T-type joint W when inputting the shaping start command. By doing so, the melting depth of the meat bead B2 is adjusted to a desired depth.

According to the present weld bead shaping method, the fillet bead B2 is melted by the laser beam R, so that the rising portion of the fillet bead B2 can be surely flattened, and the laser irradiation device 2 can be used. Since the fillet bead B2 is irradiated with the laser beam R while being moved along the extending direction of the fillet bead B2, the shaping application range is wider and the workability is better than the conventional shaping method described above.
Further, since the laser beam R is irradiated over the width of the fillet bead B2, the laser irradiation device 2 is moved in the extending direction of the fillet bead B2 only by moving once along the extending direction of the bead B2. It is possible to complete the shaping of all the parts along, and the workability is very good also in this aspect.

As mentioned above, although embodiment of this invention was described, this invention is not limited to this, For example, the following modifications can be considered.
(1) In the above embodiment, the case where the welding bead (filled bead B2) of the T-shaped joint W that has been fillet welded by the laser welding apparatus is used as the shaping control has been described. It is not limited to the T-shaped joint W. The present invention can be applied to a joint other than a fillet welded T-type joint, and can also be applied to a joint welded and joined by a welding apparatus (for example, an arc welding apparatus) other than a laser welding apparatus.

(2) In the above embodiment, the shaping of the fillet bead B2 extending linearly has been described, but the present invention is not limited to this. Even if the extension shape of the weld bead is other than a straight line, the laser irradiation device may be moved according to the extension shape.
When the bead length is extremely long, the fillet bead B2 may be divided into a plurality of regions, and each region may be shaped by a plurality of laser irradiation apparatuses 2.

(3) In the above embodiment, shaping of all parts along the extending direction of the meat bead B2 can be completed only by moving the laser irradiation device 2 once along the extending direction of the meat bead B2. As described above, the spot diameter of the laser beam R is set to the width (dimension T) of the fillet bead B2, but the present invention is not limited to this. By further narrowing down the spot diameter, the laser beam R may be irradiated only on the region near the center raised in the fillet bead B2.

(4) Furthermore, in the said embodiment, although the moving speed of the laser irradiation apparatus 2 was made constant, this invention is not limited to this. Since the shape of the fillet bead B2 may be locally changed depending on the portion of the fillet bead B2 in the extending direction, the laser irradiation apparatus according to such a local shape change of the fillet bead B2. 2 may be changed.
Instead of changing the moving speed of the laser irradiation device 2 in accordance with such a local shape change of the fillet bead B2, the irradiation energy of the laser beam R may be changed.

It is a schematic diagram which shows the weld bead shaping method concerning one Embodiment of this invention. FIG. 2 is a schematic view showing a weld bead shaping method according to an embodiment of the present invention, and is a schematic view of a T-shaped joint W as viewed from the upper side in FIG.

Explanation of symbols

  W: T type joint, B1, B2: Fillet bead, 1 ... Laser oscillator, 2 ... Laser irradiation device

Claims (3)

  A welding bead shaping method, wherein the welding bead is flattened by being irradiated and melted.   2. The welding bead shaping method according to claim 1, wherein the spot diameter of the laser beam is set to the width of the weld bead. 3. The weld bead shaping method according to claim 1, wherein the weld bead shaping method is applied to a weld bead of a laser welded T-type joint.

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