JP2917885B2 - Method and apparatus for partial cutting of steel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a partial cutting method for partially removing a defective portion of a surface of a cast or rolled steel material with a fuel gas and an oxygen gas and a cutting apparatus used in the method. It is about.

[0002]

2. Description of the Related Art As a cutting apparatus for a hot slab or the like, FIG.
The structure shown in FIG. 1 (i) is generally used. This cutting apparatus is arranged around a hot slab S, and a fuel gas (LPG) and an oxygen gas (O gas) are directed toward a surface layer of the hot slab S. ₂ ) or a crater unit 50 for blowing a mixed gas (LPG + O ₂ ), and a manifold (manifold) 51 for supplying each gas to each crater unit 50 in the upper and lower crater unit rows. By moving each piston 52 provided reciprocally in the manifold, the supply range of the fuel gas and oxygen or the mixed gas is determined, and the unit is sized for various steel dimensions.

However, with such a structure, it is impossible to supply gas only to a specific erosion crater unit, for example, only a central erosion crater unit, and to perform ablation only with the specific erosion crater unit. There is a problem that a large amount of metal loss (yield loss) occurs because the entire slab width is ablated and the surface layer other than the defective portion is also ablated.

As a means for solving such a problem, Japanese Patent Application Laid-Open No. 55-122673 proposes a fusing apparatus for fusing and removing only a portion where a defect exists to prevent an increase in yield loss. . As shown in FIG. 5 (ii), this fusing apparatus has a piston 5 provided reciprocally by a motor and a rack and pinion in each manifold 51 for supplying gas.
A fuel gas and oxygen are supplied between the partition plate 53 and the piston 52 through the pipes 54 so as to be locally melted only in a portion where a hot slab defect exists. I can cut it.

Further, in Japanese Patent Publication No. 62-39068, for example, as shown in FIG. 6, a gas supply pipe 61 and an O ₂ supply pipe 62 are provided to each of a large number of cutting crater units 60 held in a cutting apparatus. A hot partial cutting method has been proposed in which a gas / O ₂ is selectively supplied only to a corresponding cutting crater unit and only a defective portion of the slab is removed.

[0006]

However, in the conventional cutting apparatus described above, a partition plate and a pipe are provided in each chamber of the manifold, or a gas supply pipe and an O ₂ supply pipe are connected to each cutting crater unit. Because of this structure, the cutting equipment becomes complicated, furthermore, it is necessary to remodel or newly install the equipment, and there is a problem that a large investment is required. For this reason, it is very difficult to perform partial cutting using such a conventional cutting apparatus.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to perform a partial cutting by using a conventional general cutting equipment without modification. It is an object of the present invention to provide a method and a device for partial cutting of a steel material, which can easily and reliably perform partial cutting with a simple configuration.

[0008]

SUMMARY OF THE INVENTION The present invention makes it possible to partially cut a defect in a slab surface layer in an arbitrary cutting crater unit without modifying a conventional general cutting apparatus. It is.

Surface defects (cracks, etc.) occurring on the slab surface do not exist on the entire surface of the slab, but only on a specific portion, and most of the defects are constant in the slab width direction. Exists in position. Conventional general cutting equipment is composed of a plurality of cutting crater units, each of which is arranged in a direction (slab width direction) orthogonal to the direction of travel of the slab. The position of the defect occurring in the slab corresponds to the position of the defect.

[0010] From the above, in the partial cutting method of the present invention, when a gas is blown from a plurality of cutting crater units arranged in a direction perpendicular to the direction in which the steel material travels, the defective portion of the steel material is cut. An orifice is provided in the gas supply passage of the cutting crater unit at a position corresponding to the normal steel material portion of the crater unit to control the gas flow rate so that the cutting material crater unit with this orifice does not cut the steel surface. Then, only the defective steel part is partially cut by another cutting tip unit.

Further, the present invention provides a fusing apparatus for fusing a defective portion of a steel material by blowing gas from a plurality of fusing crater units arranged in a direction orthogonal to the direction of progress of the steel material. An orifice for controlling the flow rate is provided in a gas supply passage in a specific crater unit of the crater unit so that the surface of the steel material is not cut by the crater unit with the orifice. In the case where the cutting apparatus is a conventional general cutting apparatus in which a gas supply range is set by a piston in a manifold, a cutting crater unit within the gas supply range is selected and an orifice is provided.

With the above configuration, in the erosion crater unit at a position corresponding to the normal portion of the steel material such as a slab, the gas flow rate is suppressed by the loss head of the orifice attached to the gas supply passage, and the normal portion of the steel material is reduced. Only the defective portion is cut by the other normal cutting crater unit at a position corresponding to the defective portion of the steel material over the entire length in the longitudinal direction of the steel material. With conventional conventional cutting methods, only the defect on the slab surface cannot be cut, so the entire width of the slab including the defect and the normal surface is cut over the entire length of the slab in the longitudinal direction, increasing the yield loss. However, according to the present invention, only the defect generating portion can be partially cut away, so that the yield loss can be significantly reduced.

Further, since it is only necessary to attach an orifice to an ordinary erosion crater unit, partial erosion can be performed only by replacing the erosion crater unit without modifying a conventional general erosion equipment. In addition, since the structure only requires attaching the orifice to the specific crater unit, the framing equipment can have a simple structure, and the maintenance becomes easy. In addition, by using an orifice, partial abrasion can be performed easily and reliably, and gas is also discharged from the abrasion crater unit that does not perform abrasion. Can be prevented from being blocked by the molten metal, and the flame at the time of the start of cutting can be transmitted in order, the seed flame of the next cutting crater unit can be secured, and the flame from the cutting crater unit that does not cut There is an advantage that it is possible to prevent gas in the manifold from exploding due to backflow.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to an embodiment shown in the drawings. This is an example applied to partial cutting of a surface defect in a continuous casting slab. FIG. 1 shows a cutting apparatus according to the present invention, and FIG. 2 shows a cutting tip unit and an orifice / plug of the cutting apparatus. .

In FIG. 1, a large number of fusing apparatuses 1 are arranged in a direction orthogonal to the traveling direction of a slab S, similar to a conventional fusing apparatus, and include a fuel gas (eg, LPG) and oxygen (O
₂ ) Or a crater unit 2 for spraying mixed gas
And a manifold 3 for supplying each of the gases to each of the cutting crater units 2. By moving a piston 4 reciprocally provided in each chamber in the manifold 3, a fuel gas and an oxygen or mixed gas are provided. Supply range A is determined.
The piston rod 5 of the piston 4 is driven by a motor and a rack and pinion method or a pinch roller method,
Unit sizing is performed for various slab dimensions.

As shown in FIG. 2, the erosion crater unit 2 includes a head 6 detachably attached to the lower surface of the manifold 3, a heat block 7 having an erosion crater 9 at the tip, and a surface of the slab S. The head 6 and the heat block 7 are formed with a sliding riding skid 8, and a gas supply passage 10 is formed in the head 6 and the heat block 7 to communicate each chamber in the manifold 3 with the erosion crater 9.

The gas supply passages 10 are vertically arranged in four stages in FIG. 2 (i), and the lower fuel gas a, the scarfing oxygen b, the upper fuel gas c, and the upper oxygen d are arranged in the manifold 3 in order from the bottom. Introduced from each room. Further, regarding the unit arrangement direction, each gas supply passage 10a, 10b, 10c
・ A large number of 10d are provided.

In such a configuration, the gas supply port 11 located on the upper surface of the head 6 of each gas supply passage 10 is provided to an arbitrary cutting crater unit 2 ′ within the gas supply range defined by the piston 4. A metal perforated disk having a small hole 13 at the center to reduce the flow rate, that is, a special diaphragm orifice 12 is attached, and a rubber seal ring 14 for preventing gas leakage is attached around the disk. The gas flow supplied to the erosion crater 9 by the head is suppressed so that the erosion crater unit 2 'does not perform the abrasion.

Here, in order to prevent fusing, for example, a few mm is supplied to the scarfing oxygen supply port 11b, the upper fuel gas supply port 11c, and the upper oxygen supply port 11d.
The orifices 12 each having a small hole 13 having an inner diameter of 1 are attached to suppress the gas flow rate, and the lower fuel gas supply port 11a is provided with a stopper 1 which can prevent gas from leaking to the unit side.
2 ', for example, a metal disk 16 on which rubber 15 is baked may be mounted, and the supply of the lower fuel gas a may be stopped to prevent the scarfing oxygen b from burning. The orifice 1 attached to each of the supply ports 11b, 11c, 11d
As the inner diameter of the small holes 13 becomes smaller, the loss coefficient (loss head) of the orifice becomes larger and the gas flow rate can be further suppressed. However, depending on the size of the cutting device and the flow rates of the fuel gas and oxygen used. What is necessary is just to determine the optimal value.

As described above, the reason why the gas flow rate is controlled and the gas is discharged without completely stopping the gas in the erosion crater unit 2 'which does not perform the erosion is that the partial erosion is performed. The molten metal that has been cut by another cutting crater scatters and adheres to the cutting crater of the cutting crater unit that does not cut.
In order to prevent the clogging crater clogging caused by the metal, to prevent this, the flame of the crater crater unit at the start of the abrasion is transmitted from the end of the unit row in order. This is because it is possible to secure a pilot gas when the fire crater unit is ignited. Further, it is possible to prevent the gas in the manifold from exploding due to the backflow of the flame from the crater unit that does not perform the erosion.

In this embodiment, the lower fuel gas supply port 11a is provided with a plug 12 'so as to prevent the lower fuel gas a from being discharged to the slab surface. However, the present invention is not limited to this. Another scarfing oxygen b / upper fuel gas c / upper oxygen d is connected to the lower fuel gas supply port 11a.
The orifice 12 may be provided in the same manner as described above. In this case, the inside diameter of the small hole 13 of the orifice 12 is the same as that of the other, and slight erosion of the slab surface is allowed, or the inside diameter is made smaller than the other so that the slab surface is not eroded to reduce the adhesion of the metal. It may be prevented.

In the above configuration, after the piston 4 is moved according to the width of the slab to set the gas supply range, the partial cutting is performed as follows. FIG. 3 (i) shows the state of occurrence of defects on the slab surface in the continuously cast slab S. The defect K on the slab surface exists continuously at a specific position in the width direction of the continuously cast slab in the length direction. As shown in FIG. 3 (ii), with respect to such a continuously cast slab S, a normal erosion crater unit 2 is mounted at a position corresponding to a defect position on the slab surface to generate a defect. Not in the position
Attaching the crater unit 2 ′ with the orifice 12 attached to it and performing normal erosion, and the normal erosion crater unit 2 partially melts only the defect over the entire length in the slab advancing direction (slab longitudinal direction). Shave.

FIG. 4 shows a slab cross section size: 23.
3m depth for 00mm (width) x 300mm (thickness)
This is an example in which the conventional general method in the case of performing the ablation of m and the method of the present invention are compared, and it is understood that the yield loss can be significantly reduced in the present invention as compared with the conventional general method in which the entire slab is ablated.
Further, in the present invention, since it is only necessary to replace a specific portion of the fusing crater unit and mount the orifice, it is not necessary to modify the fusing apparatus, a large investment is required, and only the orifice 12 is mounted. It was extremely practical, with a simple structure and easy maintenance.

Although the above description has been made on the partial cutting of a slab, it goes without saying that the present invention can be applied to the partial cutting of other steel materials.

[0025]

As described above, according to the present invention, an orifice is provided in a gas supply passage in a cutting crater unit at a position corresponding to a normal steel material portion in a plurality of arranging crater units to control a gas flow rate. , Because only the defective part of the steel material was partially cut by another cutting crater unit,
The following effects are obtained.

(1) By merely replacing a specific portion of the erosion crater unit and attaching an orifice, it is possible to perform partial erosion capable of greatly reducing the yield loss, and there is no need to modify the erosion apparatus. Unlike the conventional partial cutting apparatus, a large investment is not required, and the cost of the cutting equipment and the cutting operation can be significantly reduced.

(2) Since it is only necessary to mount the orifice, the fusing equipment can have a simple structure, can be an inexpensive fusing equipment, and can be easily maintained.

(3) By using an orifice, partial cutting can be easily and reliably performed, and a cutting crater that does not cut is prevented from being blocked by a molten metal by another cutting crater. In addition, there is an advantage that the seed flame of the adjacent crater unit can be secured, and furthermore, it is possible to prevent the gas in the manifold from exploding due to the backflow of the flame from the crater unit that does not perform the abrasion.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a fusing apparatus according to the present invention.

FIGS. 2 (i), (ii), and (iii) are cross-sectional views, perspective views, and partial cross-sectional views showing a cutting crater unit according to the present invention, and (vi) shows a special orifice to be attached to the gas supply passage. FIG. 3 is a plan view and a side view, and FIG. 4 (v) is a plan view and a sectional view showing a plug used in place of a special orifice.

FIG. 3 (i) is a perspective view showing a state of occurrence of a slab surface defect, and FIG. 3 (ii) is a perspective view showing a partial cutting method of the present invention for the slab.

FIG. 4 is a graph comparing yield loss between the partial cutting method of the present invention and the conventional full cutting method.

FIG. 5 (i) is a cross-sectional view showing a conventional piston type fusing apparatus, and FIG. 5 (ii) is a partial cross-sectional view of the fusing apparatus for performing partial fusing using a conventional partition plate.

FIG. 6 is a cross-sectional view showing a conventional individual piping type fusing apparatus.

[Explanation of symbols]

 S: Slab (steel material) a: Fuel gas b: Scarfing oxygen c: Upper fuel gas d: Upper oxygen 1 ... Cutting device 2 ... Normal cutting crater unit for cutting 2 '... Melting without cutting Burner unit 3 ... Manifold 4 ... Piston 5 ... Piston rod 6 ... Head 7 ... Heat block 8 ... Riding skid 9 ... Ablation crater 10 ... Gas supply passage 11 ... Gas supply port 12 ... Orifice 12 '... Fluid 13 ... Small hole 14. Seal ring 15 ... Rubber 16 ... Disc

Continuation of front page (72) Inventor Hiroshi Sagi 3 Kashima, Kashima-shi, Ibaraki Prefecture Kashima Works, Sumitomo Metal Industries, Ltd. (56) References JP-A-55-153672 (JP, A) JP-A-64-3408 (JP, A) Hikaru Hei 1-159964 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) B23K 7/06

Claims (2)

(57) [Claims] When a gas is blown from a plurality of cutting crater units arranged in a direction orthogonal to a steel material advancing direction to melt a defective portion of a steel material, the gas blast unit corresponds to a normal steel material portion in the cutting crater unit. A method for partial steel cutting of a steel material, wherein an orifice is provided in a gas supply passage in a position of a blasting crater unit to control a gas flow rate, and only a defect portion of a steel material is partially eroded by another blasting crater unit. . 2. A fusing apparatus for blowing a gas from a plurality of fusing crater units arranged in a direction orthogonal to a steel material advancing direction to flaw a defective portion of a steel material. An apparatus for cutting steel material, characterized in that an orifice for controlling a flow rate is provided in a gas supply passage of a crater unit.