JP2023020367A - Upper preheating block extension and scarf unit, and assembly method for the same - Google Patents

Abstract

To provide an upper preheating block extension for a scarf unit from which an orifice plug is easily removable, the scarf unit, and an assembly method for the same.SOLUTION: An upper preheating block extension for a scarf unit which scarfs an object to scarf has: an oxygen gas jetting flow passage for shield for jetting an oxygen gas for shield; and an oxygen gas jetting flow passage for central pre-heating for jetting an oxygen gas for pre-heating. Inside the oxygen gas jetting flow passage for shield, an orifice plug for adjusting a flow rate of the oxygen gas for shield is inserted and freely removably fixed; the orifice plug is fixed via an elastic body for plug fixation.SELECTED DRAWING: Figure 1

Description

UPPER PREHEAT BLOCK EXTENSION AND SCARF UNIT AND METHOD OF ASSEMBLY THEREOF The present invention relates to an upper preheat block extension and scarf unit and a method of assembling them.

Scarfing is a process in which the decarburized layer and surface flaws (scratches) of a workpiece (for example, a steel billet) are usually removed by a thermochemical oxidation reaction of oxygen gas and fuel gas (Patent Reference 1). In steel mills, it is a surface treatment performed before rolling of billets. A device that performs this cutting is called a scarfing device (or scarfing device), and is installed in ironworks around the world.

A scarfing device is mainly composed of a roller table on which an object to be cut such as a steel piece is placed and conveyed, and a scarf unit for scarfing the object to be cut conveyed by the roller table. A flame for preheating (preheating flame) is applied from this scarf unit to the surface of the workpiece to preheat it, thereby generating molten slag. After that, the flame for cutting is switched to the flame for cutting (cutting flame), and a large amount of oxygen gas is blown to the molten slag, and at the same time, the work to be cut is advanced toward the scarf unit using a roller table, and oxidized. Cutting is performed while generating molten slag due to reaction.

JP-A-9-76060

By the way, the scarf unit consists of a head block, an upper block, a lower block and a shoe block. Among these, the role of the upper block is to burn a mixed gas of oxygen gas and fuel gas to form a preheating flame, which preheats the surface of the workpiece to be cut, and serves as a pool of molten metal ( It is for forming the molten slag).

The structure of the oxygen gas hole (ejection flow path) and the fuel gas hole for forming the preheating flame includes a tip type and an insert nozzle type. The tip type has a longer history, but since the insert nozzle type was developed about 30 years ago, the use of the insert nozzle type is gradually increasing in ironworks and the like.
However, compared to the chip type, the insert nozzle type has more parts to be incorporated, and it takes longer to assemble and disassemble.

Above all, when assembling and maintaining the upper block, it is necessary to insert and fix an orifice plug inside the oxygen gas hole to adjust the flow rate of oxygen gas in the upper preheat block extension, which is a part of it. be. As a fixing procedure, a liquid gasket (liquid packing) is applied to the upper surface of the orifice plug and inserted, and the orifice plug is fixed between the inner wall of the oxygen gas hole after the liquid gasket is dried. It started to take. This is because if the upper preheat block extension is moved before the liquid gasket dries, the orifice plug may be displaced.

Also, when disassembling and servicing the upper block, after removing the orifice plug from the upper preheat block extension, it is necessary to remove the dried liquid gasket that adheres to the inside of the upper preheat block extension and the orifice plug. It started to take time.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an upper preheat block extension for a scarf unit, a scarf unit, and a method of assembling them, in which the orifice plug can be easily attached and detached.

In order to achieve the above object, the present invention provides an upper preheat block extension for a scarf unit for scarfing an object, comprising:
The upper preheating block extension has a shielding oxygen gas ejection channel for ejecting shielding oxygen gas and a central preheating oxygen gas ejection channel for ejecting preheating oxygen gas,
an orifice plug for adjusting the flow rate of the shielding oxygen gas is inserted into the shielding oxygen gas ejection channel and fixed in a detachable manner,
The orifice plug is fixed via a plug fixing elastic body to provide an upper preheat block extension.

With such an upper preheat block extension of the present invention, the orifice plug can be firmly fixed to the inside of the shielding oxygen gas ejection passage by the elastic force of the plug fixing elastic body, and can be easily removed. In this way, the orifice plug can be easily attached and detached, and the work time required for assembly and disassembly of the upper preheat block extension can be greatly reduced compared to conventional products that use liquid gaskets.
In the conventional product, the orifice hole through which the oxygen gas passes in the orifice plug may be blocked due to the application of the liquid gasket by mistake, resulting in poor preheating and poor cutting, but in the present invention. Concerns about such orifice hole clogging can be eliminated.

Further, the orifice plug has a concave portion shallower than the thickness of the plug-fixing elastic body on the upper surface facing the inner wall of the shielding oxygen gas ejection channel,
The orifice plug may be inserted and fixed in a state in which the plug-fixing elastic body is fitted in the recess.

With such a structure, the orifice plug can be fixed by the plug fixing elastic body with a relatively simple mechanism.

Further, the plug fixing elastic body may be an O-ring.

The O-ring itself is often used as a component and is suitable because it is easily procured.

Further, the plug fixing elastic body may be made of nitrile rubber.

Such materials are preferable because they are inexpensive and have excellent wear resistance.

Further, the present invention includes a head block, an upper block having a first fuel gas ejection passage, a shielding oxygen gas ejection passage, and a central preheating oxygen gas ejection passage, and a second fuel gas ejection passage. A scarf unit for scarfing an object, comprising a lower block and a shoe block that contacts the object,
The upper block and the lower block are arranged on the front side of the head block so as to form an oxygen gas ejection slot for scarification, and the shoe block is arranged on the lower side of the head block. is arranged,
A scarf unit, wherein the upper block has an upper preheat block base provided on the head block and the upper preheat block extension of the present invention provided on the upper preheat block base. I will provide a.

As described above, compared to conventional products, the ease of assembling and disassembling the upper preheat block extension and the work time can be improved, so the scarf unit as a whole can be easily assembled and disassembled, and the necessary work time can be shortened. becomes.
In addition, the scarf unit is free from poor preheating and poor cutting caused by clogging of the orifice hole of the orifice plug by the liquid gasket.

The present invention also provides a method for assembling an upper preheat block extension for a scarf unit for scarfing an object, comprising:
An orifice plug for adjusting the flow rate of the shielding oxygen gas is inserted into the shielding oxygen gas ejection channel for ejecting the shielding oxygen gas in the upper preheat block extension and is detachably fixed. To provide a method for assembling an upper preheat block extension, characterized in that the upper preheat block extension is fixed via a plug fixing elastic body.

With this method of assembling the upper preheat block extension of the present invention, the orifice plug can be firmly fixed by the elastic force of the plug fixing elastic body. It can be assembled easily, and the work time for assembly can be greatly shortened compared with the conventional one. Moreover, when assembled in this manner, the orifice plug can be easily removed when disassembled. That is, it is possible to improve not only assembly but also disassembly and work time.
Also, it is possible to eliminate the concern that the orifice hole of the orifice plug will be blocked by the liquid gasket.

Also, when fixing the orifice plug,
In the orifice plug, a concave portion shallower than the thickness of the plug-fixing elastic body is formed on the upper surface facing the inner wall of the shielding oxygen gas ejection channel,
The orifice plug can be fixed by inserting the orifice plug into the shielding oxygen gas ejection passage in a state in which the plug fixing elastic body is fitted in the recess.

In this way, the orifice plug can be fixed by the plug fixing elastic body with a relatively simple mechanism.

Further, the plug fixing elastic body can be an O-ring.

In this manner, an easily procured O-ring can be used as the plug fixing elastic body, which is convenient.

Further, as the plug fixing elastic body, one made of nitrile rubber can be used.

The use of nitrile rubber is preferable because it is inexpensive and has excellent wear resistance.

Further, the present invention includes a head block, an upper block having a first fuel gas ejection passage, a shielding oxygen gas ejection passage, and a central preheating oxygen gas ejection passage, and a second fuel gas ejection passage. A method for assembling a scarf unit for scarfing an object, comprising a lower block and a shoe block that contacts the object, the method comprising:
The upper block and the lower block are arranged on the front surface side of the head block so as to form an oxygen gas ejection slot for cutting, and the shoe block is arranged on the lower surface side of the head block. and when,
A scarf unit characterized in that the upper block is arranged using an upper preheat block base arranged on the head block and an upper preheat block extension assembled by the method for assembling an upper preheat block extension of the present invention. to provide a method for assembling the

As described above, the ease of assembling the upper preheat block extension and the working time can be improved compared to the conventional one, so that the entire scarf unit can be easily assembled and the required working time can be shortened. In addition, when assembled by this method, disassembling can be done easily and in a short time.
Further, it is possible to assemble a scarf unit that does not cause poor preheating or poor cutting due to clogging of the orifice hole of the orifice plug by the liquid gasket.

With the upper preheat block extension and scarf unit of the present invention and the method of assembling them, the orifice plug can be easily attached and detached, the work time required for assembly and disassembly can be greatly reduced, and the orifice using a liquid gasket like the conventional one can be easily removed. It is possible to eliminate the clogging of the hole and the occurrence of poor preheating and poor cutting due to it.

It is an explanatory view showing an example of the scarf unit of the present invention. FIG. 2 is an exploded view showing an example when the scarf unit of the present invention is disassembled; FIG. 3 is a perspective view of the upper preheat block extension of the present invention; FIG. 4 is a rear view of the upper preheat block extension of the present invention; FIG. 4A is a side view and an internal structural diagram showing an example of an orifice plug dedicated to both ends; FIG. 10 is a side view and an internal structural diagram showing an example of an inner-only orifice plug; FIG. 5 is an explanatory diagram showing an example of a state in which the recess of the orifice plug and the plug-fixing elastic body are fitted; FIG. 5 is an explanatory diagram showing an example of the internal structure near the upper preheat block extension in a state where the orifice plug is inserted and fixed;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto.
First, the circumstances leading to the present invention will be briefly described.
As for the orifice plug to be arranged in the oxygen gas ejection channel for shielding of the upper preheat block extension, conventionally, the one that matches the size of the oxygen gas ejection channel for shielding was simply inserted as it is.
However, after assembling and cutting the steel pieces, etc., and disassembling and repeatedly cleaning the orifice plug, the orifice plug was worn and reduced in size, and was inserted into the oxygen gas ejection flow path for shielding. In some cases, a gap is generated between the inner wall and the stability is lost. Therefore, in order to firmly fix the orifice plug, a liquid gasket (for example, silicone-based) is used instead of an adhesive to fix the orifice plug to the inner wall of the shielding oxygen gas ejection channel.

The liquid gasket was adopted because it does not cause a chemical reaction even if it comes into contact with oxygen gas, it is resistant to heat, and it has a proven track record of being used for scarf unit maintenance. However, as described above, assembly and disassembly takes time and effort, and problems such as clogging of the orifice hole may occur due to application of the liquid gasket to the wrong place.
As a result of intensive research conducted by the present inventors, it was found that the use of an elastic body for fixing the orifice plug facilitates assembly and disassembly without requiring much labor or time. The inventors have found that the problem of pore clogging can be prevented, and have completed the present invention.

FIG. 1 shows an example of the scarf unit of the present invention. Also, FIG. 2 shows an exploded view of the scarf unit. The scarf unit 1 has a mechanism for supplying oxygen gas and fuel gas to a workpiece (for example, a steel billet) to remove decarburized layers and flaws present on the surface of the steel billet by thermochemical reaction. It is prepared.
First, the scarf unit 1 of the present invention is roughly divided into a head block 2, an upper block 3, a lower block 4 and a shoe block 5.
The head block 2 may be made of brass, for example. The upper block 3, lower block 4, and shoe block 5 may be made of copper, for example. If it is made of copper, it is preferable because it has excellent thermal conductivity and can exhibit a high cooling effect. However, these materials are not particularly limited.

The head block 2 has a structure (manifold structure) provided with collective pipes for sending oxygen gas and fuel gas to the injection flow passages of each block and the oxygen gas injection slots for cutting, which will be described later. In addition, water for water cooling of each block can also be sent.
An upper block 3 and a lower block 4 are arranged on the front side of the head block 2 . These two blocks are arranged with a gap between them. A space between these two blocks constitutes an oxygen gas ejection slot 6 for scarfing, and oxygen gas for scarfing can be ejected.

The upper block 3 includes an upper preheat block base (hereinafter also referred to as UPBB) 7 provided on the head block 2 and an upper preheat block extension (hereinafter referred to as UPBE) of the present invention provided on the upper preheat block base 7. ) and 8.
The upper block 3 (UPBB7 and UPBE8) is provided with a first fuel gas ejection passage 9, a shielding oxygen gas ejection passage 11, and a central preheating oxygen gas ejection passage 12. As shown in FIG. Further, the lower block 4 is provided with a fuel gas second ejection passage 10 . Oxygen gas or fuel gas can be ejected therethrough, respectively.
More specifically, the shielding oxygen gas ejection channel 11 is a path for the shielding oxygen gas, and the central preheating oxygen gas ejection channel 12 is a path for the preheating oxygen gas.
Examples of fuel gases include LPG, LNG and coke gas.

A shoe block 5 is arranged on the lower surface side of the head block 2 . A skid 13 is attached to the lower surface of the shoe block 5 . The skid 13 is a portion that comes into contact with a steel piece during cutting.

Here, the UPBE of the present invention will be described in detail.
FIG. 3 is a perspective view of UPBE8. It is drawing seen from the joint surface side with UPBB7. Although an orifice plug (hereinafter also referred to as a plug) 14 before being inserted into the shielding oxygen gas ejection channel 11 is also shown, the elastic body for fixing the plug is omitted.
4 is a rear view of the UPBE 8 with the plug 14 already inserted.
As shown in FIGS. 3 and 4, the UPBE 8 is formed with one or more (especially a plurality of) shielding oxygen gas ejection passages 11, each of which is provided for adjusting the flow rate of the shielding oxygen gas. A plug 14 is insertable.

Here, the two plugs for the two shielding oxygen gas ejection passages at both ends are slightly smaller than the seven plugs for the inner seven shielding oxygen gas ejection passages. FIG. 5 shows a plug dedicated to both ends (upper row is a side view, lower row is a diagram of the internal structure seen from the top side). In addition, FIG. 6 shows a plug dedicated to the inside (the upper row is a side view, and the lower row is a diagram of the internal structure seen from the upper surface side).
Each plug 14 has one mounting jig hole 15 in the center and two orifice holes 16 on either side. The mounting jig hole 15 is a screw hole into which the tip (screw shape) of a separately prepared T-shaped mounting jig can be inserted. is inserted into the shielding oxygen gas ejection channel 11 of the UPBE 8 at . It should be noted that the mounting jig hole 15 does not penetrate in the plug dedicated to both ends, and the mounting jig hole 15 is a through hole in the plug dedicated to the inner side (circled portion). However, it is not particularly limited, and may or may not be penetrated, and can be determined as appropriate.
Also, the number and formation positions of the orifice holes 16 are not particularly limited. At the time of preheating or cutting, the orifice 16 adjusts the flow rate of the oxygen gas and blows it out.

Further, the plug 14 may be detachably fixed in the shielding oxygen gas ejection channel 11 via the plug fixing elastic body, and the specific form is not particularly limited. An example will be described below.
FIG. 7 shows an example of a recess formed in the upper surface of the plug and a state in which the plug fixing elastic body is fitted into the recess (the upper row is a top view, the middle row is a top view of the fitted state of the plug fixing elastic body, The lower part is a side view of the mated state).
The plug 14 has, for example, a circular concave portion 17 formed in its upper surface (facing the inner wall when inserted into the shielding oxygen gas ejection channel 11). A plug fixing elastic body (hereinafter also referred to as an elastic body) 18 (for example, an O-ring) can be fitted into the recess 17 and has a depth smaller than the thickness of the elastic body 18 . Therefore, in the state of being fitted into the concave portion 17, a portion of the elastic body 18 protrudes upward. With such a configuration, the elastic body 18 fitted in the recessed portion 17 when inserted into the shielding oxygen gas ejection channel 11 is unlikely to come off from the recessed portion 17, and is fitted in the recessed portion 17 in the inserted state. The protruding portion of the elastic body 18 pressed against the inner wall of the shielding oxygen gas ejection channel 11 . That is, the elastic force of the elastic body 18 firmly fixes the plug 14 inside the shielding oxygen gas ejection channel 11 . It can be fixed by a relatively simple mechanism of fitting the concave portion 17 and the elastic body 18 therein, and since it is not adhered like a liquid gasket, it can be easily removed, which is very convenient.

The thickness of the plug 14, the depth of the recess 17, and the thickness of the elastic body 18 are not particularly limited. For example, it can be appropriately determined according to the size of the shielding oxygen gas ejection flow path 11 and the like.

Since it can be fixed through the elastic body 18 without using a liquid gasket, the liquid gasket is accidentally applied to the side surface of the plug 14, and the orifice hole 16 is blocked by the liquid gasket. can prevent problems. Therefore, it is possible to prevent the occurrence of poor preheating and poor cutting due to the clogging.

Although an example in which the circular recess 17 is provided on the upper surface of the plug 14 is shown here, the present invention is not limited to this. It is also possible to provide Also, the shape of the recess 17 is not particularly limited, such as circular, square, or triangular in plan view. However, it is preferable that all the plugs 14 have the same shape and location of the recesses in view of manufacturing and maintenance of such recesses.

Further, although an O-ring is used as an example of the elastic body 18 here, the elastic body 18 is not particularly limited, and can be appropriately determined depending on the shape of the concave portion 17 in plan view. An O-ring is suitable because it is easy to procure.
The material of the elastic body 18 may be, for example, nitrile rubber, which is relatively inexpensive and has excellent abrasion resistance, but is not particularly limited. Any material may be used as long as it is resistant to oxygen gas and heat and has enough elasticity to fix the plug 14 .
For this elastic body 18, it is also possible to divert and share a thing equivalent to what is used for sealing in other parts of the scarf unit 1 of the present invention (for example, a sealing O-ring 21 to be described later). can. Such a diversion product can prevent an unnecessary increase in the number of types of parts in the overall scarf unit 1, which is preferable in terms of management and maintenance.

FIG. 8 shows the internal structure around the UPBE 8 with the plug 14 inserted and fixed. Hereinafter, description will be made along each ejection channel.
In the upper block 3 , the oxygen gas ejection passage is branched from the UPBE 8 into two: a shielding oxygen gas ejection passage 11 and a central preheating oxygen gas ejection passage 12 .
The aforementioned plug 14 is inserted into the shielding oxygen gas ejection channel 11 and fixed via an elastic member 18, and basically, the shielding oxygen gas is ejected through the orifice hole 16 thereof.
The shielding oxygen gas ejection channel 11 is tapered and has a step 19 . The step 19 prevents the plug 14 from advancing any further, and also secures a simple sealing performance.
By the way, oxygen gas is injected not only from the orifice hole 16 but also from the gap between the inner wall of the shielding oxygen gas ejection channel 11 and the plug 14 due to the existence of the elastic body 18 and further from the gap between the step 19 and the plug 14 beyond that. There is no particular problem even if is leaking. It is sufficient to appropriately adjust the supply amount of the main oxygen gas so that an appropriate flow rate of the shielding oxygen gas can be jetted out.

In addition, an insert 20, which is a cylindrical member having a through hole formed along the central axis, is inserted into the UPBE8. It is designed to be ejected. A plurality of grooves along the axial direction are formed in the outer peripheral portion of the cylindrical insert 20 . A first fuel gas ejection passage 9 is formed so as to surround the insert 20, and the fuel gas is ejected through the gap between the inner wall of the first fuel gas ejection passage 9 and the groove on the outer periphery of the insert 20. It is possible. A sealing O-ring 21 is provided so that the oxygen gas and the fuel gas do not mix inside the UPBE 8 .
Due to the mechanism including such an insert 20, preheating oxygen gas is ejected from the center and fuel gas is ejected concentrically from the outer periphery, producing a powerful (high temperature) long-range preheating flame. It is possible to generate.

Further, as described above, the lower block 4 is provided with the second fuel gas ejection passage 10 so that the fuel gas can be ejected. A cutting oxygen gas ejection slot 6 is provided to allow the cutting oxygen gas to be ejected.

Next, a method for assembling the UPBE and scarf unit of the present invention will be described.
Although an O-ring is used as the elastic body 18 and the UPBE 8 in which the plug 14 having the concave portion 17 on the upper surface as shown in FIGS. Any method may be used as long as the orifice plug is detachably fixed in the shielding oxygen gas ejection channel via the plug fixing elastic body.

First, the elastic body 18, which is an O-ring, is fitted into the recess 17 of the plug 14. As shown in FIG. With the elastic body 18 fitted in the concave portion 17 as described above, the plug 14 is inserted up to the step 19 inside the shielding oxygen gas ejection channel 11 of the UPBE 8 using a mounting jig. The elastic force of the elastic body 18 presses against the inner wall of the shielding oxygen gas ejection channel 11, thereby firmly fixing the plug 14 inside. The UPBE8 is assembled in this manner.

Next, an upper block 3 and a lower block 4 are arranged on the front side of the head block 2 . At this time, the oxygen gas ejection slots 6 for cutting are formed by arranging them with a space between them.
When the upper blocks 3 are arranged, for example, the UPBB 7 of the upper blocks 3 can be arranged with respect to the head block 2 first, and then the UPBE 8 can be arranged with respect to the UPBB 7 . Alternatively, the UPBB 7 and the UPBE 8 may be joined to assemble the upper block 3 and then arranged on the head block 2 .
Also, a shoe block 5 is arranged on the lower surface side of the head block 2 .
Thus, the scarf unit 1 is assembled.

With the assembling method of the present invention as described above, it is possible to assemble simply and in a short period of time, and it is also very easy to disassemble.

A method of scarfing using the scarf unit 1 of the present invention will be described below. Here, for the sake of simplicity, the case where the scarf unit 1 is arranged only on the surface side (upper surface side) of the steel piece will be described as an example. However, the present invention is not limited to this, and it is of course possible to dispose on two or four sides of the steel slab and simultaneously melt cut the two or four sides of the steel slab.
First, a steel piece is placed on a roller table for feeding the steel piece, and conveyed toward the scarf unit 1 side. At this time, the scarf unit 1 is positioned sufficiently above the roller table and the steel piece.
After the end of the billet is conveyed under the scarf unit 1, the scarf unit 1 is moved (in this case lowered) toward the billet and the skid 13 is brought into contact with the surface (upper surface) of the billet. (closing process).

After contact, the scarf unit 1 is moved away from the surface of the billet. This separation may be approximately 1/2 inch (about 12.5 mm). Then, the billet is slightly pulled by the roller table (that is, transported away from the scarf unit 1) and positioned so that the preheating flame from the scarf unit 1 hits the edge of the surface of the billet in the next preheating step.

Next, while the skid 13 is in a non-contact state with the surface of the steel piece, the fuel gas is jetted at a low speed from the first fuel gas jetting passage 9, and the fuel gas is jetted from the second fuel gas jetting passage 10 at a high pressure. At the same time, low-pressure oxygen gas is ejected from the oxygen gas ejection channel 11 for shielding, oxygen gas is ejected at high speed from the oxygen gas ejection channel 12 for central preheating, and oxygen gas is ejected from the oxygen gas ejection slot 6 for cutting at low speed. While blowing out, it is ignited by an igniter, a preheating flame is generated, and molten slag is generated on the surface of the steel billet (preheating process). The preheating flame at this time becomes a linear concentrated flame in the width direction of the billet.
The preheating time may be, for example, about 5 seconds when the steel billet is a hot billet and about 60 seconds when it is a cold billet.

After the molten slag is generated, the flow rate of the gas is switched, and the preheating flame is switched to the cutting flame. That is, while oxygen gas is ejected at a large flow rate (for example, about 200 kPa) from the oxygen gas ejection slots 6 for cutting, the oxygen gas ejection passages 11 for shielding and the oxygen gas ejection passages 12 for central preheating are ejected. For protection only, a small flow rate of oxygen gas and a small flow rate of fuel gas are jetted from the first fuel gas jet passage 9 and the second fuel gas jet passage 10 . At the same time, the scarf unit 1 is moved (lowered) toward the steel piece, and while the skid 13 is in contact with the surface of the steel piece, the steel piece is conveyed to the scarf unit 1 side by the roller table. By blowing a large amount of oxygen onto the molten slag and advancing the steel slab toward the scarf unit 1 in this manner, the surfaces of the steel slabs can be cut one after another while generating the molten slag due to the oxidation reaction. (Smelting process).

Although the steel slab has warpage and bending, as described above, the skid 13 of the scarf unit 1 is brought into close contact with the surface of the steel slab, and the scarf unit 1 and the steel slab can be welded together. By performing cutting while keeping the distance of constant), the cutting margin can be made uniform over the entire cut surface of the billet. This cutting margin can be, for example, about 1.5 to 4 mm.
Further, during the shaving process, the high-pressure water from the high-pressure water nozzle blows away unnecessary molten slag toward the inner wall of the smoke hood surrounding the steel billet, enabling the shaving process.
A cut product can be obtained by the above-described cutting process.

EXAMPLES The present invention will be described in more detail below with reference to Examples and Comparative Examples of the present invention, but the present invention is not limited to these.
(Example)
Using the method for assembling the UPBE of the present invention, an orifice plug was inserted and fixed inside the shielding oxygen gas ejection channel of the UPBE for the scarf unit, and the UPBE was assembled. Also, after assembly, the UPBE was disassembled and the orifice plug was removed from its interior. The time required for this assembly and disassembly was measured.
As the orifice plug, one having a concave portion on the upper surface as shown in FIG. 7 was used. At the time of assembly, an O-ring made of nitrile rubber was inserted into the shielding oxygen gas ejection channel by means of a mounting jig in a state where the O-ring was fitted in the recess, and fixed by the elastic force of the O-ring.
Conversely, the assembly was disassembled by pulling out the orifice plug inside the shielding oxygen gas ejection channel using a mounting jig. The O-ring could be easily removed from the recess of the pulled-out orifice plug.

(Comparative example)
Using a conventional UPBE assembly method, an orifice plug was inserted into and fixed to the inside of the shielding oxygen gas ejection channel of the UPBE for the scarf unit, and the UPBE was assembled. Also, after assembly, the UPBE was disassembled and the orifice plug was removed from its interior. The time required for this assembly and disassembly was measured.
As the orifice plug, unlike the embodiment, the same one as the conventional one, which does not have a concave portion on the upper surface, was used. At the time of assembly, a liquid gasket (silicone type) was applied to the upper surface, inserted into the shielding oxygen gas ejection channel using a mounting jig, and left as it was to dry and fix the liquid gasket.
Conversely, the assembly was disassembled by pulling out the orifice plug inside the shielding oxygen gas ejection channel using a mounting jig. Since the dried liquid gasket adhered to both the upper surface of the pulled-out orifice plug and the inner wall of the shielding oxygen gas ejection channel, it was removed. Specifically, first, most of the deposits of the liquid gasket adhering to these were scraped off using a knife, and the parts that could not be scraped off were removed using a brass spiral brush. For the orifice plug, a pin vise was also used to remove clogging from the orifice hole.

A comparison of the time required for assembly and disassembly revealed that the comparative example required 180 minutes for assembly, while the example required only 5 minutes for assembly. This is because it took a particularly long time to dry the liquid gasket in the comparative example. On the other hand, in the example, such drying was not necessary, and as a result, 175 minutes could be shortened compared to the case of the comparative example.
Further, while the decomposition took 20 minutes in the comparative example, the decomposition could be completed in 5 minutes in the example. This is due to the fact that it took a long time to remove the liquid gasket in the comparative example. On the other hand, in the example, such a removal work was unnecessary, and as a result, the time could be shortened by 15 minutes compared to the case of the comparative example.

In the present invention as in the embodiment, the time required for assembling and disassembling the UPBE can be shortened, so that the time required for assembling and disassembling the scarf unit can also be greatly shortened as a whole.

When a plurality of UPBEs were assembled in the same procedure as in the comparative example, there was a case where the liquid gasket was erroneously applied not only to the upper surface but also to the orifice hole. Since the present invention as in the embodiment does not cause such a mistake, it is also excellent in terms of safety.

It should be noted that the present invention is not limited to the above embodiments. The above embodiment is an example, and any device that has substantially the same configuration as the technical idea described in the claims of the present invention and produces similar effects is the present invention. It is included in the technical scope of the invention.

1... scarf unit of the present invention, 2... head block, 3... upper block,
4... Lower block, 5... Shoe block, 6... Oxygen gas injection slot for cutting,
7 ... upper preheat block base,
8 ... the upper preheat block extension of the present invention,
9 First fuel gas ejection channel, 10 Second fuel gas ejection channel,
REFERENCE SIGNS LIST 11: Shield oxygen gas ejection channel, 12: Central preheating oxygen gas ejection channel,
13... skid, 14... orifice plug, 15... mounting jig hole,
16... Orifice hole 17... Concave portion 18... Elastic body for fixing plug,
19...Step, 20...Insert, 21...O-ring for sealing.

Claims (10)

An upper preheat block extension for a scarf unit for scarfing an object,
The upper preheating block extension has a shielding oxygen gas ejection channel for ejecting shielding oxygen gas and a central preheating oxygen gas ejection channel for ejecting preheating oxygen gas,
an orifice plug for adjusting the flow rate of the shielding oxygen gas is inserted into the shielding oxygen gas ejection channel and fixed in a detachable manner,
An upper preheat block extension, wherein the orifice plug is fixed via a plug fixing elastic body. The orifice plug has a concave portion shallower than the thickness of the plug-fixing elastic body on the upper surface facing the inner wall of the shielding oxygen gas ejection channel,
2. The upper preheat block extension according to claim 1, wherein the orifice plug is inserted and fixed while the plug fixing elastic body is fitted in the recess. 3. The upper preheat block extension according to claim 1, wherein said plug fixing elastic body is an O-ring. The upper preheat block extension according to any one of claims 1 to 3, wherein the plug fixing elastic body is made of nitrile rubber. A head block, an upper block having a first fuel gas ejection passage, a shielding oxygen gas ejection passage, and a central preheating oxygen gas ejection passage, a lower block having a second fuel gas ejection passage, and a subject. A scarf unit for abrading an object to be abraded, comprising a shoe block in contact with the abraded object,
The upper block and the lower block are arranged on the front side of the head block so as to form an oxygen gas ejection slot for scarification, and the shoe block is arranged on the lower side of the head block. is arranged,
The upper block comprises an upper preheat block base provided on the head block and an upper preheat block extension according to any one of claims 1 to 4 provided on the upper preheat block base. A scarf unit characterized by comprising: A method for assembling an upper preheat block extension for a scarf unit for scarfing an object, comprising:
An orifice plug for adjusting the flow rate of the shielding oxygen gas is inserted into the shielding oxygen gas ejection channel for ejecting the shielding oxygen gas in the upper preheat block extension and is detachably fixed. A method for assembling an upper preheat block extension, characterized in that the plug is fixed via an elastic body for fixing the plug. When fixing the orifice plug,
In the orifice plug, a concave portion shallower than the thickness of the plug-fixing elastic body is formed on the upper surface facing the inner wall of the shielding oxygen gas ejection channel,
7. The upper preheater according to claim 6, wherein said orifice plug is fixed by inserting said orifice plug into said shielding oxygen gas ejection channel in a state in which said plug fixing elastic body is fitted in said recess. How to assemble the block extension. The method for assembling an upper preheat block extension according to claim 6 or 7, wherein the plug fixing elastic body is an O-ring. The method for assembling an upper preheat block extension according to any one of claims 6 to 8, wherein the plug fixing elastic body is made of nitrile rubber. A head block, an upper block having a first fuel gas ejection passage, a shielding oxygen gas ejection passage, and a central preheating oxygen gas ejection passage, a lower block having a second fuel gas ejection passage, and a subject. A method for assembling a scarf unit for scarfing an object to be abraded, the method comprising:
The upper block and the lower block are arranged on the front surface side of the head block so as to form an oxygen gas ejection slot for cutting, and the shoe block is arranged on the lower surface side of the head block. and when,
An upper preheat block base in which the upper block is arranged on the head block, and an upper preheat block extension assembled by the method for assembling an upper preheat block extension according to any one of claims 6 to 9 are used. A method for assembling a scarf unit, characterized in that the scarf unit is arranged in a

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