JPH0119997B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for efficiently removing slag (burr) formed and attached to a melt-cut steel material.

[Prior Art] At steelworks, steel products made into slabs by continuous casting or hot rolling are cut into appropriate sizes using a blow-cutting device (torch) using a gas flame, and then subjected to heat treatment, rolling, etc. Sent to the next process.

In this fusing process, as shown in FIGS. 5 and 6, slag (burr) S, which is a mixture of iron oxide and molten metal iron, is generated and is blown away by the flame of the torch, forming the steel material 2. It is welded so as to have a root R at the corner of the welded surface 2a and the lower surface 2b, and is attached to the lower surface 2b.

If such steel material 2 is rolled as it is, flaws will occur on the surface of the product and the rolling rolls will be damaged, so it is necessary to remove the slag S sufficiently.

This slag removal work is carried out by cutting the surface of the steel material to which the slag has adhered by cutting with a small gas torch, or by cutting by automatic cutting machine B as shown in FIG. This automatically moves along the melting surface 2a of the steel material 2, relative to the steel material 2,
A crater 1a is provided for injecting flame into the slag S on the surface of the steel material 2 and melting the corresponding portion. In addition,
In this figure, the position of the steel material 2 is reversed and the slag is removed from the top, but a method of directly cutting from the bottom is also adopted.

[Problems to be Solved by the Invention] However, it is not easy to efficiently remove slag using such a device. In other words, as mentioned above, slag is a mixture of iron oxide and metal iron, but its adhesion is not continuous with a uniform thickness, and the degree of adhesion is thick and thin in some parts, and also intermittently. There were some areas where the slag was removed, and even if this slag was removed by continuous cutting operations, there was still a lot left behind. For this reason, the present invention burns metal iron to generate heat, creates high-temperature molten slag (slag), and flows this slag in the cutting direction to efficiently transfer heat and continuously cut the relevant part. It was designed to be melted and machined.

In addition, in the case of manual work, the position of the torch and the flow rate of gas are delicately controlled to generate slag continuously, but with automatic cutting machines such as the one mentioned above, this is not possible. It was difficult to control.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention removes slag that has roots and adhered to the corners where the melted surface and the lower surface of the melted steel material intersect. In the method of removing the steel material by cutting it using a nozzle that automatically moves relative to the steel material, the preceding first nozzle is used to cut the welded surface, and the second nozzle that follows is used to remove the lower surface of the steel material. It is designed to be melt-cut.

[Operation] In this slag removal method, the molten surface that is not covered with slag is melted to a thickness of about 2 to 3 mm by the preceding first crater, so the corner where the molten surface and the lower surface intersect is The roots of the slag in the corners are removed, and slag is generated and flows near the corners, and the high-temperature slag preheats the slag and steel at the corresponding locations. Then, the second crater that follows uses the slag generated and melted by the first crater to melt the lower surface and completely remove the slag from which the roots have been removed.

[Example] Hereinafter, an example of the method of the present invention will be described with reference to the drawings.

FIG. 1 shows an automatic cutting apparatus A for carrying out the present invention. In this figure, 1 is a first crater for cutting the melted surface (side surface) 2a of the steel material 2, and 3 is the lower surface 2b of the steel material 2. The second crater 4 to be melt-cut is a base to which the first crater 1 and the second crater 3 are attached.

The first crater 1 and the second crater 3 have the same structure,
A fuel gas supply pipe 6 and an oxygen supply pipe 7 are connected to a box-shaped manifold 5 fixed to the base 4, and a nozzle 8 having a rectangular cross section projects diagonally from the manifold 5. A shoe 9 that comes into contact with the steel surface is attached to the portion facing the steel surface. The first crater 1 faces the melting surface 2a, and the second crater 3 faces the lower surface 2b so as to inject flame obliquely forward.

The base plate 4 has an L-shaped vertical section, and the vertical portion 4a is longer than the horizontal portion 4b.
This base 4 is installed along the line of movement of the steel material 2, and its position can be adjusted in the vertical and horizontal directions with respect to the line.

The first crater 1 is fixed to a long hole 10 formed in the base 4 by a bolt 11, and by changing the mounting position, the distance l from the second crater 3 can be adjusted.

In this example, the steel material 2 is moved, but the base 4 may be moved by being placed on a cutting cart, for example.

Next, a method for removing slag from a steel material using the automatic cutting apparatus A as described above will be explained with reference to FIGS. 2 to 4.

First, the distance l between the craters 1 and 3 of the automatic melt cutting device A is set to an appropriate value. This value is determined by considering the type, thickness, and cutting speed of the steel material 2, but in the inventors' experience, it is 10 mm to 70 mm.
The range was appropriate. Further, the flow rates of each fuel gas and oxygen at the craters 1 and 3 are determined in consideration of the temperature of the steel material 2, the amount of slag attached, and the like. Next, the vertical and horizontal positions of the base 4 are adjusted, and as shown in FIG. to come. Then, the steel material 2 is moved at an appropriate speed along a movement line (parallel to the melting surface) and melt-cut.

In this way, the welded surface 2 of the steel material 2 is
When point a is melt-cut, the roots R of the slag at the corners of the melted surface 2a and the lower surface 2b are removed, and the high-temperature slag generated during the melt-cutting is removed from the corners, as shown in Fig. 3. Accumulates near the area. Subsequently, when the lower surface 2b of this part is melted by the flame from the second crater 3, the slag S is melted, blown away, and removed due to the influence of the high temperature slag flowing near the corner. (See Figure 4).

In such a cutting method, high-temperature slag is generated at the first crater 1, and the second crater 3 uses this slag to melt the lower surface 2b of the steel material 2 heated by the first crater 1. This auxiliary effect facilitates fusing. Further, since the root R of the slag S is removed by the first crater 1, the slag S is also reliably removed.

In addition, in order to finish the melted surface well and to suppress the occurrence of burrs (secondary fins) caused by melting, an air pipe or the like is installed on the front side of the second crater 3 to direct the molten slag to the outside. You can also blow it away.

Further, in the above example, the surface to which the slag S adhered (lower surface 2b) was directly facing downward during fusing, but it can also be performed by inverting the surface as in the case of FIG. 7.

[Effects of the Invention] As described in detail above, the present invention automatically removes the slag attached to the corner where the melted surface and the lower surface of a cut steel material intersect, relative to the steel material. In this method, the welded surface is cut by the preceding first crater, and the lower surface of the steel material is cut by the second crater, which follows. In addition to generating slag to assist lower surface cutting, the roots of slag are removed, the relevant part of the steel material is preheated, and then lower surface cutting is performed using the second crater. This provides an excellent effect in that slag can be easily and reliably removed automatically regardless of conditions such as unevenness.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing an apparatus for carrying out an embodiment of the method of the present invention, Figs. The figure is a perspective view showing a steel material cut by a torch, FIG. 6 is a sectional view, and FIG. 7 is a perspective view showing a conventional slag removal method. 1...First crater, 2...Steel material, 2a...Fused surface, 2b...Bottom surface, 3...Second crater, S...Slag.

Claims (1)

[Claims] 1. A method for removing slag attached to the lower corner of the melted surface of a melted steel material by cutting it with a nozzle that automatically moves relative to the steel material. A method for removing slag from a steel material, characterized in that the molten surface is melt-cut by a first crater, and then the lower surface of the steel material is melt-cut by a second crater following this.