JPH0999345A - Mold for casting beam blank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold for casting a beam blank which can economically and arbitrarily set a cooling groove of a mold block at the long wall side. SOLUTION: In the long wall side mold block in the mold for casting the beam blank, a thin copper plate 1 composed of copper or copper alloy is bent along the shape of molten steel pouring surface of the long wall side mold block. Many boss-studs 4 applying inner screwing work are welded on the molten steel pouring surface and the reverse side surface of the copper plate 1. A backup plate 2 for forming the arbitrary cooling water passage 3 between the backup plate and the copper plate 1 is arranged so as to face the boss-studs 4 with the inner screw, and bolts 5 inserted through this backup plate 2 are fastened with the boss-studs 4 with the inner screw.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel mold used for continuous casting of iron and steel, and more particularly to a fillet and a web for a beam blank mold for casting H-shaped steel used for building materials. The present invention relates to a novel structure of a long side mold block having parts.

[0002]

2. Description of the Related Art FIG. 4 shows a schematic sectional structure of a conventional beam blank casting mold in the horizontal direction. First, the long side mold block 10 has a projecting portion in the central portion along the longitudinal direction. In order to perform continuous casting of H-shaped steel, a pair of long side mold blocks 10 are arranged such that the central projecting portions are opposed to each other with a predetermined distance therebetween, and a pair of short strips each having a substantially flat surface on both sides thereof. By arranging the side mold blocks 20, a space 30 surrounded by the two pairs of mold blocks and having a substantially H-shaped cross section is formed, and molten steel is injected into the space 30 from above. The poured molten steel is heated by a mold to be solidified and then drawn out as H-shaped steel from the lower side. In addition, each mold block 10, 20
Are provided with cooling grooves 11 and 21, respectively, for circulating cooling water.

Conventionally, in order to manufacture the long side mold block 10 of a beam blank casting mold, thick oxygen-free copper, silver-containing copper, chrome copper, and chrome zirconium copper are prepared and machined out. However, most of the copper materials used (8/9 to 9/10) were wastefully discarded, which was extremely uneconomical. Moreover, due to the structure of the mold, the cooling groove 11
The structure is severely restricted, and at present, it is dealt with by providing holes on the upper and lower side surfaces of the mold material itself, which are also close to the inner wall of the mold as much as possible. Therefore, there is a problem that it is not always possible to form a water passage that can supply the necessary amount of water to the necessary place for its function.
It takes a lot of time and labor to process holes for water passages and to process the ends of the holes.

That is, the conventional long side mold block 10
In order to obtain a uniform cooling effect including the projecting portion provided in the central portion when the cooling groove 11 is formed in FIG.
As shown in FIG. 5, the cooling groove 11 must be formed along the longitudinal direction of the mold block 10 using the long-axis tool T1. In order to pass water through the cooling box 11 from the water box arranged on the back surface of the mold block 10 (on the side opposite to the molten steel injection surface), as shown in FIG.
It is necessary to form a large number of holes 13 reaching the cooling groove 11 from the back surface of the. Moreover, since the cooling grooves 11 must not be independent of each other and need to be laterally connected to each other internally, machining thereof is extremely difficult. In addition, after machining, both ends of the cooling groove 11 must be closed to prevent water leakage. In the figure, T2 is a drilling tool, T3 is a tapping tool, 14 is a tap for mounting on a water box, and J is a jig. Even with such complicated processing, it is very difficult to obtain a uniform cooling effect, and in reality,
A member called a flow path adjusting rod having a substantially half-moon cross section is inserted into the cooling groove 11 to perform delicate flow path adjustment, but even then it is often impossible to achieve uniform cooling, so that It is a cause of quality deterioration.

The mold block manufactured in this way is
Normally, while protecting the copper surface and avoiding the mixture of copper in the slab, it is coated with chromium, nickel, nickel-iron alloy, nickel-phosphorus alloy, nickel-boron alloy, nickel-cobalt alloy, etc. Then, every time the copper surface is exposed, the surface coating film is completely removed by cutting to be regenerated. Therefore, the thickness of the copper plate is reduced to some extent each time it is regenerated, and the copper plate is eventually discarded. The number of times that reproduction is possible is usually limited to 3 times and at most 5 times.

[0006]

As described above, in the long side mold block of the beam blank casting mold, in order to obtain the desired shape, the copper material more than necessary is prepared, and it takes a lot of time and time. It is made with effort. In addition, the life of the product is only a few times, and the product is discarded. Further, it is impossible to freely provide the structure of the cooling groove necessary for casting a good quality slab due to the structural limitation of the mold. Furthermore, the conventional molds have been extremely inadequate both economically and in terms of cooling function.

An object of the present invention is to solve all the problems of the conventional molds and to provide a beam blank casting mold which is economical and which can arbitrarily set the cooling groove of the long side mold block. It is what

[0008]

Means for Solving the Problems As a result of earnest studies on means for solving the above problems, the present inventors have found that a copper plate which is sometimes used in a short side mold block of a beam blank mold or a bloom mold. S for fixing to the anti-molten steel contact surface of
It was found that if a mold having a so-called stud bolt welding structure formed by stud welding US stud bolts can be manufactured, the above problems can be solved at once.

First, as shown in FIG. 6, a thin copper plate 1 is bent by press working, and a machined product having a certain size is prepared. The weldability and structure of the SUS304 stud bolt 12 to the copper plate 1 are measured. The included problems were examined. As a result, it was found that welding of the stud bolt in the portion corresponding to the slope area a shown in FIG. 6 was a problem. That is, as shown in FIG. 6, when the stud bolt is welded in the direction of the arrow b, the joint area with the copper plate increases, which causes a problem in the cooling performance of the copper plate in a part.
Since the mounting direction and mounting angle of the stud bolt when welding the stud bolt to the copper plate cannot be carried out accurately, even if the stud bolt is acceptable, the welded stud bolt will always pull the copper plate itself in an oblique direction. It was found that it is extremely difficult to put the copper plate and the backup plate supporting and reinforcing the copper plate into practical use due to a problem in joining property. In order to solve these problems, an attempt was made to weld the stud bolt in the direction of arrow c in FIG. 6, but the welded stud bolt interfered with the installation of the backup plate 2 provided with the cooling groove 3. It turns out that there is a new problem that it cannot.

As a result of various studies, the inventors of the present invention did not stud-weld a stud bolt directly to a copper plate, but used a boss / stud (hereinafter referred to as an internally-threaded boss / stud) which is internally threaded. After stud welding to the copper plate, attach the backup plate to the copper plate, and then
It was discovered that the problems could be solved at once by fixing the backup plate and the copper plate with a set bolt, and the present invention was completed.

The mold of the present invention thus manufactured is
Since the backup plate can be used repeatedly, the only part to be discarded after being regenerated several times is the copper plate with the internally threaded boss studs stud welded, which is very economical. The material of the backup plate may be SUS material or iron material, but when it is made of iron material, it may be plated with electric nickel or electroless nickel for rust prevention. Furthermore, in the conventional structure, the structure of the cooling groove is almost limited, whereas in the mold of the present invention, the surface of the backup plate has an arbitrary depth and width,
Since grooving can be performed in any direction, uniform cooling, which is restricted by the conventional structure, can be achieved, and it is extremely effective in improving the quality of cast slabs.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the essential structure of a mold according to the present invention. In the figure, reference numeral 1 denotes a thin copper plate made of copper or a copper alloy, which is bent along the shape of a long side mold block having a protruding portion in the central portion along the longitudinal direction. Nickel plating (or nickel-iron alloy plating) is preferably formed on the surface of the molten steel injection surface of the copper plate 1. This nickel plating prevents copper from mixing into molten steel and contributes to the quality improvement of the slab, and also prevents the copper material from being scraped by the solidified shell of molten steel and improving the life of the mold. It also contributes to. It is also preferable to form nickel plating on the surface of the copper plate 1 opposite to the molten steel injection surface. As a result, stainless steel bosses with internal threads
When welding the stud 4, the joining strength is dramatically improved. This is a finding by the present inventors, and it is considered that the formation of a nickel-copper alloy in the welded portion is the cause of the improvement in bonding strength. Further, by applying this nickel plating, it is possible to prevent the cooling water from directly contacting the copper plate 1 and to suppress rusting. However, it goes without saying that the applied nickel plating thickness does not impair the heat removal effect and is a thickness necessary for the rust prevention effect and the improvement of the welding strength. The internally threaded boss stud 4 to be welded is preferably SUS30
It is made of four materials, and is internally threaded for fastening the set bolt 5. A backup plate 2 made of stainless steel is arranged on the surface of the copper plate 1 opposite to the molten steel injection surface. A large number of slit-shaped grooves 3 are formed on the surface of the backup plate 2, and a cooling water channel is formed between the backup plate 2 and the copper plate 1 by bringing them into close contact with each other. In order to bring the backup plate 2 and the copper plate 1 into close contact with each other, the tip of the set bolt 5 fitted into the backup plate 2 is fastened to the inner thread portion of the internally threaded boss / stud 4. As shown in FIG. 2, for example, a nylon washer 5 is attached to the tightening portion of the set bolt 5.
1, a SUS plain washer 52, a seal washer 53 are provided, and a seal packing or a water leakage prevention packing (not shown) is provided in the peripheral portion between the backup plate 2 and the copper plate 1.
It goes without saying that water leakage prevention treatment is performed with the interposition of.

In the mold of the present invention, unlike the case of the conventional long side mold block, as shown in FIG. 3, the surface of the backup plate 2 that is in direct contact with the surface of the copper plate 1 opposite to the molten steel injection surface. Since the cooling groove 3 can be directly processed in the mold, the width and depth of the cooling groove 3 and even the direction thereof can be arbitrarily designed and manufactured, and there is no restriction on the uniform cooling generated in the current long side mold, and the slab It is possible to provide the cooling groove 3 taking only the quality of the above into consideration. Therefore, it is extremely effective in improving the quality of cast slabs.

Next, for the short side mold block, a flat thin copper plate 20 made of copper or a copper alloy is used, and a mold block in which a slit-shaped cooling groove 21 is formed immediately below the molten steel injection surface is used. . Such a mold block is
For example, a slit can be formed on the surface of a copper plate, the slit can be filled with wax, the surface can be electrically conductive, and copper can be built up by electroforming, and then the wax can be melted to produce it. Therefore, detailed description thereof will be omitted. Alternatively, as another structure example of the short side mold block, a flat thin copper plate 20 is prepared, and a large number of stud bolts are welded to the surface opposite to the molten steel injection surface, and the stud bolts are made of stainless steel. The backup plate 22 by inserting it into the backup plate 22
You may fasten with a nut from the back side of. In the latter case, a large number of slit-shaped grooves 21 are formed on the surface of the backup plate 22 and are brought into close contact with the copper plate,
A cooling water passage is formed between the copper plate and the copper plate. The present invention does not limit the structure of the short side mold block, and other structures may be used.

The long-side mold block and the short-side mold block configured as described above are arranged in pairs so as to face each other, and are assembled so as to surround a substantially H-shaped space as shown in FIG. , Used as a mold for beam blank casting. When the surface coating layer on the molten steel injection surface is worn away by the operation,
The thin copper plate 1 made of copper or copper alloy is separated from the backup plate 2 for repair, and is discarded as many times as the conventional mold, but the backup plate 2 can be used any number of times, and the thick copper material can be used. Material cost and processing cost can be dramatically reduced as compared with the conventional structure in which the cutting process is performed.

The thickness of the copper plate 1 used in the long side mold block of the present invention is preferably 5 to 50 mm, and preferably 1 in consideration of thermal conductivity as seen from the heat removal effect.
The range is 0 to 20 mm.

[0017]

EXAMPLE As shown in FIG. 7, the present inventors have a width of about 4 mm.
A trapezoidal copper plate 1 made of chrome-zirconium copper having a length of 50 mm, a length of about 600 mm and a thickness of about 30 mm is manufactured by forging,
The molten steel contact surface was machined to form a machining reference surface, which was then attached to the machining jig J1 to machine the opposite surface (anti-molten steel side) and the four side surfaces. Then, a SUS304 inner threaded boss / stud 4 was welded to the copper plate 1 by a stud welding method. The dimension of the long side mold completed by the above procedure was 410 mm width × 560 mm length × 20 mm thickness.

On the other hand, as shown in FIG. 8, a separately prepared backup plate 2 made of SUS304 was also machined by the same procedure, but the reference surface was made the anti-copper plate contact surface and the copper plate 1
A large number of water flow grooves 3 were provided in advance on the contact surface with. Further, the backup plate 2 was attached to the processing jig J2, and the holes 6 through which the set bolts 5 passed and the holes 13 through which cooling water was passed through the water passages 3 were processed to complete the backup plate.

The tapped bossed copper plate 1 and the SUS304 backup plate 2 prepared in advance in the above two separate steps were integrated and the molten steel contact surface was coated with 0.8 mm of nickel-iron alloy. Then, as shown in FIG. 9, it was attached to the water box 8 with the fixing bolt 7. In the figure, 9 is a reinforcing plate of the backup plate. Furthermore, as shown in FIG. 10, when the conventional short side copper plate 20 coated with a slit type nickel-iron alloy was incorporated at the same time as a beam blank mold and subjected to actual casting, the conventional long side was obtained. Not only was the cooling efficiency superior to that of the mold, but also good quality H-section steel could be cast.

[0020]

According to the present invention, the manufacturing cost of the beam blank mold can be remarkably reduced, and the degree of freedom in the design of the cooling groove can be obtained. Therefore, the cooling uniformity of the slab can be measured, and the slab can be cooled. A significant improvement in quality is possible.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration of a main part of an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG.

FIG. 4 is a sectional view of a conventional example.

FIG. 5 is a perspective view showing a process of processing a long side mold block in a conventional example.

FIG. 6 is a cross-sectional view of a comparative example with respect to the present invention.

FIG. 7 is a perspective view showing a long side copper plate processing step in the present invention.

FIG. 8 is a perspective view showing a processing step of the backup plate according to the present invention.

FIG. 9 is a perspective view showing a step of mounting the long side mold block of the present invention in a water box.

FIG. 10 is a sectional view showing the overall configuration of a beam blank mold of the present invention.

[Explanation of symbols]

 1 Thin copper plate 2 Backup plate 3 Cooling groove 4 Boss / stud with internal thread 5 Set bolt

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masayuki Mizuto 2398 Hisaidai, Yanagitsu-cho, Fukuyama-shi, Hiroshima 2398 Nomura Plating Fukuyama Factory, Ltd. Hiraoki 2398 Nomura Plating Co., Ltd.Fukuyama Factory (72) Inventor Ryoichi Ikeo 474 Obata, Gokaso-cho, Kanzaki-gun, Shiga Japan Japan Stud Welding Co., Ltd.Shiga Works

Claims (2)

[Claims] 1. A pair of long side mold blocks having a projecting portion along the longitudinal direction in the central part are arranged such that the central projecting parts are opposed to each other with a predetermined distance therebetween, and are perpendicular to this. Beam blank casting in which a pair of short side mold blocks whose surfaces are substantially flat in the direction are arranged to face each other to form a substantially H-shaped space surrounded by each mold block, and molten steel is injected into this space. In the casting mold, a thin copper plate made of copper or copper alloy is bent along the shape of the molten steel injection surface of the long side mold block, and the surface opposite to the molten steel injection surface of this copper plate is internally threaded. A large number of bosses and studs that were welded were stud-welded, and a backup plate for forming an arbitrary cooling water channel with the copper plate was arranged so as to face the internally-threaded boss and stud, and was inserted into this backup plate. Bolt A mold for beam blank casting, which is fastened to the internally threaded boss / stud. 2. A welded portion formed by forming a nickel plating on a surface of a thin copper plate made of copper or a copper alloy on the side opposite to the molten steel injection surface and welding a stainless steel internally threaded boss / stud to the nickel plated surface. The mold for beam blank casting according to claim 1, wherein a nickel-copper alloy portion is formed on the mold.