JPS629760A - Method for cutting continuously cast steel ingot - Google Patents

Abstract

PURPOSE:To reduce the time for cutting by measuring the surface temp. of an ingot in the intended position for cutting in the transverse direction of the ingot, setting the cutting speed distribution of a cutting torch corresponding to the temp. distribution in the transverse direction and automatically controlling the cutting speed of the cutting torch in accordance therewith. CONSTITUTION:An IR camera 2 is installed on an upper stream side of the cutting torch 1A apart at a distance L therefrom and the luminance on the ingot surface in the intended position for cutting is measured in the transverse direction of the ingot. An A/D converter converts the luminance to a temp. and inputs the same to a CPU3. The CPU3 outputs the same to a monitor TV4 and sets the cutting speed distribution corresponding to the temp. distribution of the ingot surface. The distance L and the cutting position are corrected in the CPU3 and thereafter the cutting speed of the torch 1A is automatically controlled.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method for cutting slabs produced by continuous casting in continuous casting equipment, and in particular to a method for cutting slabs produced by continuous casting in continuous casting equipment. This invention relates to a cutting method that can automatically cut pieces.

<Prior art and its problems> In a continuous casting facility, a slab is pulled out by pinch rolls and is cut into a desired length by a gas cutter that travels with the slab, and then supplied to the next process.

Here, part of the corner of the slab has a large heat dissipation area, so the temperature of the slab decreases.

For this reason, when cutting slabs with a cutting torch, the cutting speed is manually lowered during the initial stage of cutting the slab, and since the temperature of the slab is high in areas other than some corners, the cutting speed is manually increased to maintain a constant cutting speed. It was cut off.

In such conventional manual methods, the cutting speed is slow, and under high-speed casting, a casting speed Dow 2 or the like is required, resulting in poor productivity and poor workability.

Furthermore, Japanese Patent Application Laid-Open No. 58-13453 "Slab Cutting Device for Continuous Casting Equipment" proposes a device that measures the temperature of the slab before the cutting point and automatically cuts the slab at the optimum cutting speed corresponding to the temperature. has been done.

However, in the case of this device, the temperature measured is at one location, and the optimum cutting speed is also constant. Therefore, no consideration is given to temperature changes in the width direction as described above.

This invention was proposed in view of the above circumstances, and its purpose is to provide a cutting method that can automatically perform cutting with an optimal cutting speed distribution corresponding to the surface temperature distribution of the slab in the width direction. be.

<Means for solving the problem> The cutting method according to the present invention measures the surface temperature of the slab at the planned cutting position in the width direction of the slab using an infrared camera, a photoelectric element, etc., and measures the temperature distribution in the width direction. After setting the cutting speed distribution of the cutting torch and performing cooling correction as necessary, the cutting speed of the cutting torch is automatically controlled based on this cutting speed distribution, thereby shortening the cutting time.

<Example> The present invention will be described below based on an illustrated embodiment.

As shown in FIG. 1, the cutting machine 1 has a cutting torch on the front side, and when a desired cutting point is reached, it is attached to the slab S and the cutting torch 1A is moved to perform the cutting.

An infrared camera 2 is installed at a distance upstream of one of the cutting torches, and measures the temperature distribution on the slab surface at the position to be cut.

The infrared camera 2 detects the brightness, converts it to temperature, and inputs it to the CPU 3.

The optimal value of the cutting torch 1A for the slab surface temperature is input into the CPU 3 in advance as shown in FIG.

The slab surface temperature distribution is, for example, as shown in Figure 3, and is output to the monitor "rV4" as well as to the CPU S.
In this step, a cutting speed distribution corresponding to the slab surface temperature distribution (see FIG. 3(B)) is obtained, and the controller of the cutting torch 1A is automatically controlled based on this cutting speed distribution.

In addition, since the cutting torch 1A and the infrared camera 2 are separated, it is necessary to perform temperature correction by cooling and correction for each position, taking into account the cooling while the cutting progresses from the edge to the center.
After the distance and the temperature of the cutting position are corrected in U5, the cutting speed is set.

The thermometer is not limited to an infrared camera type, but may also include a number of photoelectric elements such as CCDs (charge-coupled devices) lined up in the width direction of the slab, and a type that uses a single detector to scan the entire width of the scanning mirror. But it's okay.

Furthermore, the temperature measurement device may be made movable with the cutting torch to measure the temperature just before the torch cutting point.In this case, temperature correction does not require correction by cooling, but only correction of the detection element characteristics. good.

<Specific Example> This uses two gas cutting torches and a pressure of 8Ky.
This is an example in which a slab of 10In2, width 1240ii x thickness 2701IK was cut into lengths of 10771, and the results shown in the following table were obtained.

As is clear from this table, in the present invention, the required cutting time is reduced by 0.23 m1n for this slab size.

This shortening of the cutting time increases the charging temperature of the hot rolling heating furnace during direct charging and reduces the fuel consumption rate.

Furthermore, as is clear from the table, the consumption consumption of O2 for cutting and propane gas is reduced.

<Effects of the Invention> As described above, according to the present invention, the surface temperature of the slab at the planned cutting position is measured in the width direction of the slab, the cutting torch cutting speed distribution corresponding to this temperature distribution in the width direction is set, and this cutting Since the cutting speed of the cutting torch is automatically controlled based on the speed distribution, the following effects are achieved.

(1) As shown in Figure 3 (B), the time required from the start of cutting to the completion of cutting can be shortened compared to the conventional method by the shaded area, and the casting speed is reduced due to the torch cutting rate during high-speed casting. The temperature of the slab is higher than before, and the fuel consumption rate is lower. Additionally, the unit consumption of propane gas is reduced, resulting in energy savings.

(11) Automatic control improves work efficiency.

(iii) The cutting width is made constant, yield is improved, and sagging (slag) accompanying cutting is reduced.

Ov) There is no need to reduce the casting speed due to uncut parts, cutting failures, backfires, etc. caused by torch cutting.

[Brief explanation of drawings]

Fig. 1 is a schematic perspective view showing an apparatus for carrying out the cutting method according to the present invention, Fig. 2 is a graph showing the relationship between slab temperature and cutting speed, and Figs. 6 (A) and (B) are slabs. It is a graph showing the relationship between slab temperature and cutting speed with respect to width. 1... Cutting machine, 1A... Cutting torch, 20 fist infrared camera, 3... CPU, 4... Monitor TV 0 rice & v 8 Slab temperature ℃ Procedure amendment document ■ November 25, 1985 wMJ 60th anniversary patent application No. 149697 2, Name of the invention: Continuous casting slab cutting method 3, Relationship with the case of the person making the amendment Patent applicant 4, Agent address ■107 Shadow Akasaka Telephone, 6-5-21 Akasaka, Minato-ku, Tokyo ( 586) 8741 October 9, 1985 (shipment date') 60. 10.
297, Subject of amendment: Brief description of the drawings in the specification and Drawing 1, "Figure 3 (A), (B)" from the second line from the bottom of page 7 of the specification to the first line of page 8 teeth·
...There is a graph. " is corrected to "Figure 3 is a graph showing the relationship between slab temperature and slab width in the upper part and cutting speed in relation to slab width in the lower part." 2. Distribute Kuchizonotora 3■ on separate sheet 0j and read 11 correct stories. ′ Slab temperature ℃

Claims (1)

[Claims] (1) In the method of cutting continuous cast slabs produced by continuous casting into predetermined lengths using a gas cutter, the surface temperature of the slab at the planned cutting position is measured in the width direction of the slab, and the temperature distribution in the width direction is A continuous casting slab cutting method characterized by setting a corresponding cutting torch cutting speed distribution and automatically controlling the cutting speed of the cutting torch based on this cutting speed distribution.