JPH0433554B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for removing slag generated by welding using laser light.

Prior Art As is well known, when arc welding is performed using, for example, a coated arc welding rod, slag is formed on the surface of the welded metal in order to protect the welded metal from the atmosphere. Conventionally, the slag has been removed by shot blasting or by hitting the weld with a hammer. However, since the shape of the welded part is uneven as shown in FIG.
It was difficult to completely remove this by the above-mentioned shot blasting (not shown) or the like.

For example, when overlay welding is applied to a press die for the purpose of correction, multi-layer overlay welding is performed, so the surface of the slag 3 that could not be removed by shot blasting etc. as described above is shown in Fig. 2. By applying multi-layer welding, slag 3
There were times when I got involved. As a result, defects occur in the welded portion, resulting in a disadvantage that the strength of the welded portion is reduced. On the other hand, when applying anti-rust coating to the welded parts, as mentioned above, the remaining slag 3 peels off from the bead 2 after coating, resulting in the inconvenience that rust occurs in the areas where the slag 3 was attached and remained. It was hot too.

Therefore, in order to prevent the occurrence of defects or rust in the welded part due to the entrainment of slag 3, conventionally,
The bead 2 and the slag 3 were further ground down using a grinder (not shown) or the like to remove the slag 3.

However, in the method of removing the slag 3 by scraping off the weld, the scraped weld must be further welded in order to scrape off the expensive build-up material. There was a problem in that a large amount of overlay material was required to form the part, and the welding operation time was increased, resulting in an increase in welding costs.

Purpose of the Invention The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method for removing slag from a welded part, which can easily remove slag adhering to or remaining in the welded part without scraping the welded part. This is the purpose.

Structure of the Invention The present invention is characterized in that the slag adhering to and remaining in the welding part is irradiated with a laser beam to decompose the slag, and at the same time, compressed gas is sprayed onto the slag to scatter it.

Embodiment An embodiment of the present invention will be described below with reference to FIG. Note that the same parts as in the conventional example are given the same reference numerals, and the description thereof will be omitted. FIG. 3 is a diagram for explaining a method for removing slag 3 that has adhered to and remained in the welded portion. First, the slag 3 is irradiated with a laser beam 4 guided from a laser oscillator (not shown), focused by a lens 5. Then, the slag 3 will melt due to the energy of the laser beam 4, or cracks will occur in the slag 3 due to thermal stress. And at the same time as irradiating laser light 4,
Compressed gas, such as compressed air, is blown onto the slag 3 from the nozzle 6. By doing so, the slag 3 that has been melted or cracked by the laser beam 4 is blown away from the valley between the beads 2, 2 together with compressed air.

At that time, when a laser beam is irradiated into the valley between the beads 2 and 2, the laser beam 4 is reflected from the surroundings.
Since the slag 3 is also concentrated in the slag 3, the slag 3 can be easily decomposed in a short time. Therefore, when performing multi-layer build-up welding, the slag 3 can be removed in a short time after welding without scraping off the weld, thereby avoiding a significant temperature drop in the weld. This eliminates the need for heating the welded part with a heating furnace or the like during the welding process to prevent cracks and the like that would otherwise occur. Therefore, welding work time can be shortened. Further, even if the area around the welded part has a complicated shape, the slag 3 can be easily removed by following the above-described procedure as long as the welded part is in a place where the laser beam 4 can reach. Accordingly, when painting the welded parts, the paint can be applied even to the parts where the slag 3 has adhered or remains, so that rust prevention measures can be taken more effectively.

Note that the laser beam 4 is not limited to a condensed beam, but may be a parallel beam. Further, the compressed gas to be blown onto the slag 3 is not limited to air, and may be, for example, nitrogen gas or the like.

Effects of the Invention As is clear from the above explanation, according to the method of the present invention, the slag adhered to and remaining in the welded area is irradiated with a laser beam, and the slag decomposed by simultaneously spraying compressed gas. Since the slag is blown away, the slag attached to and remaining on the weld can be easily removed without scraping the weld. Therefore, when performing multi-layer build-up welding, a multi-layer build-up welded part without defects due to slag entrainment can be obtained in a short time, and waste of build-up material caused by scraping off the weld part can be avoided. . As a result, welding costs can be reduced. Furthermore, slag can be removed in a short time,
A significant temperature drop in the welded area can be prevented. Therefore, it is no longer necessary to heat the welded part in order to avoid a significant temperature difference between the layers of the multilayered welded part, and the welding operation time can be further shortened.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a bottom bead, FIG. 2 is a sectional view of a multilayer welded part, and FIG. 3 is a sectional view for explaining an embodiment of the method of the present invention. 2...bead, 3...slag, 4...laser light, 6...nozzle.

Claims (1)

[Claims] 1. A method for removing slag from a welded part, which is characterized by irradiating the slag attached or remaining on the welded part with a laser beam to decompose the slag, and at the same time blowing compressed gas onto the slag to scatter it.