KR100612491B1 - Guide roll of continuous casting manufactured by double centrifugal casting process of liquid plus liquid, and transportation trans roll using the same - Google Patents

Abstract

The present invention relates to a performance guide roll manufactured using double centrifugal casting and a transfer trans roll using the same. More specifically, the durability of the performance guide roller for guiding the slab in the continuous casting machine in the performance process during the steel production process Centrifugal mold preheating process, coating coating process inside the centrifugal mold, outer layer molding process for injecting predetermined molten metal during centrifugal mold rotation, outer layer temperature checking process, and predetermined molten metal The bearing is installed on the guide roll and the shaft hole manufactured using the double-centrifugal casting process in which the inner layer molding process, which is injected and placed on the inner surface of the outer layer, and the temperature checking process and the cooling / heating process of the inner layer are sequentially performed. The transfer transformer roll is started.

Description

GUIDE ROLL OF CONTINUOUS CASTING MANUFACTURED BY DOUBLE CENTRIFUGAL CASTING PROCESS OF LIQUID PLUS LIQUID, AND TRANSPORTATION TRANS ROLL USING THE SAME}

1 is a schematic view showing a playing process of the steel manufacturing process for the background of the present invention.

Figure 2a is a cross-sectional view of the conventional guided play rollers of the hard facing type.

Figure 2b is an enlarged photograph of the surface of the conventional playing guide roller.

Figure 3 is a block diagram showing a centrifugal casting process sequence for producing a play guide roll of the present invention.

Figure 4 is a schematic view showing a centrifugal casting state for producing the playing guide roll of the present invention.

Figure 5a is a perspective view of the playing guide roll according to the present invention.

Figure 5b is a photograph of the playing guide roll according to the present invention.
Figure 5c is a photograph of the microstructure of the junction interface of the playing guide roll according to the present invention.

6 is a cross-sectional view of the roller using a tube manufactured using the liquid plus liquid centrifugal dual casting process according to the present invention.

Figure 7 is a graph showing the positional hardness of the roll by the double centrifugal casting and the roll according to the prior art according to the present invention.

<Explanation of symbols for the main parts of the drawings>

1: Ladle 2: Molten Steel 2a: Cast

3: TUNDISH 4: MOLD

10: performance guide roll 10a: performance guide roller

11: OUTER LAYER 12: INNER LAYER

13: shaft 14: bearing

20 centrifugal mold 21 centrifugal mold preheating process

22: coating coating process 23: centrifugal mold rotation process

24: outer layer molding process 25: 1st temperature check process

26: inner layer molding process 27: secondary temperature check process

28: cooling / heat treatment process

The present invention relates to a play guide roll manufactured by using different liquid double centrifugal casting, and more particularly, to convert iron (molten steel) from a liquid state into a solid state (cast) during a process for manufacturing steel materials. The present invention relates to a playing guide roll mounted on a continuous casting machine of a playing process for guiding the cast continuously.

Steel is produced through four major processes: the steelmaking process, which is the basic process of melting iron ore through the blast furnace, to produce molten iron, the steelmaking process to remove impurities from the molten iron, and the casting process to make liquid iron into a solid of a certain shape. This is a rolling process for making such hardened iron into a steel sheet or wire rod.

In the steel manufacturing process, the reproducing process is a process of continuously solidifying molten steel into cast steel pieces having a constant shape through a continuous casting machine, and the process includes ladle (1) 1 for receiving molten steel 2 as shown in FIG. , A tundish (3) for temporarily storing molten steel received from the ladle (1), a mold (4) for shaping the molten steel (2) into a predetermined shape, and withdrawing from the mold (4) It consists of a play guide roller 10a for guiding the cast steel (2a), the cast steel (2a) is divided into slab (Slab), Bloom (Bloom), Billet (Billet), etc. according to the production type, such wire rod Is usually used by cutting the required length.

Herein, the present invention relates to a playing guide roll which is a material of the playing guide roller 10a.

Play guide roller 10a, the outside is required heat resistance and durability, the inside is required impact resistance, referring to Figure 2a showing a cross-sectional structure of the prior art, welding with a hard facing (HARD-FACING) -based material Rolls having an outer layer (6) and an inner layer (7), which are forged rods requiring impact resistance, are rotatably fixed to the shaft (8) via a bearing (9). As a structure, the manufacturing method is as follows.

First, a performance guide roll consisting of a tubular outer layer (6) and a tubular inner layer (7) in contact with the inner surface thereof is manufactured, and a bearing (9) is provided at both ends of the inner layer (7). ) Is installed in the shaft (8), and a plurality of such play guide roller (10a) is provided so that the cast (2a) is rotated while contacting the outer surface of the play guide roller (10a) as shown in FIG. The cast piece 2a is guided in a curved form.

By the way, the conventional performance guide roll shown in Figure 2a, first, forging the chrome-molybdenum steel (SCM) or nickel-chromium-molybdenum steel (SNCM) having heat resistance and rigidity in order to manufacture the inner layer (7) After making the forging bar of the, and then through the drilling operation so that the shaft penetrates into the center of the forging bar to obtain a tubular inner layer (7).

In addition, the outer surface of the inner layer 7 is welded evenly on the entire surface using a martensite-based welding material, and then the welded surface is circularly processed by using a machine tool such as a lathe. The performance guide roll was manufactured by the method which becomes an outer layer.

However, the manufacturing process requires not only a lot of labor and cost to process the inside when drilling the center of the forging bar to manufacture the inner layer 7, but also the outer layer 6 is formed by welding so that the surface Many cracks are formed in the.

That is, as shown in the photographs of FIGS. 2B and 2C showing an enlarged surface of the outer layer 6, atypical cracks are formed on the surface thereof, and a large number of cracks are formed inside the outer layer 6 as well as the entire surface. It is thought to have occurred.

However, as shown in FIG. 1, the play guide roller 10a installed in the continuous casting machine maintains continuous contact with high temperature cast steel, and thus scratch wear and tear occurs due to oxidation scale of the surface of the cast steel with high temperature corrosion wear and punishment due to the static steel static pressure. Considering the fact that the deformation stress on the slab weight in the horizontal portion and the reaction force for the force and the straightening force of the slab acts as a crack as described above has a problem of rapidly lowering the durability of the outer layer (6).

Moreover, the cracks on the surface of the outer layer 6 are formed not only on the surface of the outer layer 6 but also on the interface with the inner layer 7 as well, so that the bonding force with the inner layer 7 is very weak. There is a problem that frequently replaces (10a), which eventually extends to a problem that greatly reduces the productivity of steel.

Accordingly, the present invention is to solve the above problems, the present invention through the process of centrifugal casting of different liquids and liquids in a continuous casting machine in continuous contact with the hot slabs and a lot of stress The purpose of the present invention is to improve the heat resistance and durability of the performance guide roller, and to improve the strength of the joint between the outer layer and the inner layer.

In addition, an object of the present invention is to install a bearing inside the roll manufactured by double centrifugal casting to be applied to the transfer transformer roll.

In order to achieve the above object, the present invention excludes a manufacturing method of joining the surface of a solid inner layer to a surface of a solid inner layer, such as welding, in the manufacture of a performance guide roll. The outer layer and the material 2 of the inner layer of the liquid phase, as well as sequentially centrifugally cast, as well as characterized in that the material of the mutual exchange at the interface between the outer layer and the inner layer.

In another aspect, the present invention is characterized in that the bearing is installed in the shaft hole of the roll manufactured by the double centrifugal casting process and applied to the transfer transformer roll.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. 3 to 6.

Figure 3 is a block diagram showing a centrifugal casting process sequence for producing a playing guide roll of the present invention, Figure 4 is a block diagram showing a centrifugal casting state for producing a playing guide roll of the present invention.

Centrifugal casting is the casting of molten metal into a tubular shape by using the centrifugal force generated when rotating a mold having a circular internal cavity (CAVITY) at a high speed. That is, some pressure is applied to the molding by the centrifugal force. At the same time, it refers to a method of obtaining sound castings through separation of impurities by specific gravity.

The advantage of centrifugal casting is that it does not need a spout, pressure, core, etc. like a mold for general casting, and it has the advantage of precisely dimensioning by powerful centrifugal force and obtaining precise castings by rapid cooling.

It is noteworthy that according to the present invention, when using the general centrifugal casting, through the double centrifugal casting injecting and molding a predetermined molten metal constituting the outer layer and the inner layer at a time difference considering the temperature in one centrifugal mold Is to make a performance guide roll.

That is, the centrifugal mold 20 having a circular interior is provided in a state capable of rotating at a high speed as indicated by the arrow of FIG. 4 by a rotation driving means such as a motor, by using the centrifugal mold 20. The production guide roll 10 of Figure 5, as shown in Figure 3, centrifugal mold preheating process 21, coating coating process 22, centrifugal mold rotation process 23, outer layer molding process 24 , The first temperature check process 25, the inner layer forming process 26, the second temperature check process 27, and the cooling / heat treatment process 28.

Referring to FIG. 3, the centrifugal mold preheating process 21 preheats the centrifugal mold 20 to a predetermined temperature before injecting the molten metal to be molded in the centrifugal mold 20, which is a high temperature in a liquid state. When molten metal is injected into the centrifugal mold 20, it is a process for preventing or mitigating impact or acceleration of partial solidification due to a sudden temperature difference.

The coating coating process 22 is to facilitate the separation of the casting from the centrifugal mold 20 after the casting molding is completed. The coating coating is sprayed on the entire surface of the mold 20, and the coating agent for release purposes is silica. Release agents such as SILICA and zirconia and surfactants may be selected or used in combination.

After the coating coating process 22, a predetermined molten metal for forming the outer layer 11 is injected into the centrifugal mold 20 while performing the centrifugal mold rotation process 23 for rotating the centrifugal mold 20 at a high speed.

In this way, as shown in FIG. 4, the liquid outer layer 11 material is adhered to the inner surface of the centrifugal mold 20 at a uniform thickness and density by centrifugal force, and the tubular outer layer 11 having a predetermined thickness is formed thereafter. The inner layer forming step 26 is performed on the inner surface of the outer layer 11.

At this time, it is important to inject molten metal of another material to form the inner layer 12 at an appropriate timing in the state before the outer layer 11 is completely hardened, which is the inner layer and the inner surface of the outer layer 11. In order to improve mutual bonding between the outer layer 11 and the inner layer 12 by allowing different materials to be exchanged and kneaded at the interface of the outer surface contact section of the layer 12.

Although the timing of injecting the inner layer 12 material into the liquid phase varies depending on the material of the outer layer 11, the temperature from the inherent liquid line (LIQUIDUS LINE) of each selected material is as low as 10 ° C. and as high as 200 ° C. It is preferable to inject the inner layer material in the range up to the temperature.

The liquidus line represents the temperature at which the liquid metal starts to solidify, i.e., after the outer layer forming process 24 is completed, the material selected as the outer layer 11 gradually cools down and passes over the liquidus temperature to eventually complete. The temperature falls below the temperature at which the solidification occurs, and during this process, for example, when the material of the inner layer 12 whose intrinsic liquidus temperature of the selected material is 1000 ° C. is injected, the outer layer 11 in the first temperature check process 25 is performed. The liquid material is injected when the solidification temperature of the C) is within the range of 1010 ° C to 1200 ° C.

Injecting inert gas or nitrogen gas during this process increases the bonding surface and bonding strength.

If the temperature is lower than 1010 ℃, the rapid cooling in the complete liquid state not only affects the physical properties but also results in insufficient material exchange at the interface with the outer layer by non-metal oxides. More mixed layers between outer layers can be halved for the desired purpose of each part.

In this case, the materials may be exchanged and kneaded at the boundary between the inner surface of the outer layer 11 and the outer surface of the inner layer 12 formed by the centrifugal force.

When the molding of the inner layer 12 is completed by the above method, the secondary temperature check process 27 for measuring the temperature of the inner layer 12 is performed again, and the measured temperature in the secondary temperature check process 27 is When the temperature of the solidus temperature in the range of ± 50 degrees, the next step of cooling and heat treatment process 28 is carried out.

On the other hand, the cooling / heat treatment process 28 is satisfied according to the usual cooling and heat treatment process after casting production, so a detailed description thereof will be omitted.

Figure 5a is a perspective view of the playing guide roll according to the present invention, Figure 5b is a perspective photo of the playing guide roll according to the present invention, Figure 5c is a microstructure diagram of the interface of the joint portion of the playing guide roll according to the present invention, the cooling And after the heat treatment step 28, as shown in Figure 5a, the outer layer 11 is bonded to the outer layer 11 to the outer play layer of the tubular playing guide roll 10 is manufactured, the actual picture of the playing guide roll 10 Referring to FIGS. 5B and 5C, the materials of the outer layer 11 and the inner layer 12 may be interchanged with almost no distinction.

FIG. 6 is a cross-sectional view of a roller using a tube manufactured using a liquid + liquid centrifugal dual casting process according to the present invention, and is formed at both ends of inner surfaces of the inner layer 12 using the playing guide roll 10 shown in FIG. The bearing 14 is installed, and the playing guide roller 10a of the structure in which it is built up on the shaft 13 is shown.

The production guide rollers 10a manufactured as described above are provided in plural and installed in a continuous casting machine for manufacturing molten steel as cast steel, as shown in FIG. 1 to guide the continuous flow of the cast steel.

In the selection of the preferred material for the performance guide roll 10, the outer layer 11 is in continuous contact with the hot slab on the operation in the continuous casting machine, so the corrosion resistance to the fluorine-containing mold powder with excellent heat and abrasion resistance On the other hand, the inner layer 12 requires impact resistance and mechanical durability corresponding to the bulging force caused by the static steel static pressure generated in the continuous casting machine, the reaction force against the slab straightening force, and the deformation stress against the slab weight in the horizontal part. do.

Therefore, the outer layer 11 selects martensite-based stainless steel (STAINLESS), and the inner layer 12 selects from chromium-molybdenum steel (SCM) or nickel-chromium-molybdenum steel (SNCM). Preferably, the performance guide roll 10 manufactured as described above may be changed in physical properties or materials according to the purpose of use.

For example, at least one of neobium (Nb), tungsten (W), and vanadium (V) may be selected and incorporated into martensitic stainless steel selected as the material of the outer layer 11 for the purpose of improving hot strength and durability.

In addition, the roll 10 manufactured by the double centrifugal casting process may be used for other purposes in addition to the continuous casting machine according to the material selection.

For example, when the outer layer 11 is selected from high chromium (Hi-Cr) steel or tungsten (W) steel, and the inner layer 12 is taken as chromium-molybdenum steel (SCM), the CPC roll (solid-liquid phase bonding) ( Continuous Pouring Process for Cladding; The CPC method developed by Fujiko, Japan, draws the core material slowly while injecting the melt of the outer layer material between the vertical core material and the water-cooled mold and solidifying the core material and welding together. And cladding the outer layer).

The difference between the liquid plus liquid double centrifugal casting of the present invention described above and the conventional, hardfacing process and CPC process are shown in Table 1 and FIG. 7.

TABLE 1

Process division condition problem  Ⓐ  Hardfacing Process  Solid + Liquid (Welding) -Weld beads are divided. Non-metallic inclusions are present. -After use, the surface of the turtle is cracked. Ⓑ CPC process Solid + Liquid (Casting) -The interface is unstable due to the rapid change in hardness (see Fig. 7). Ⓒ Liquid + Liquid Double Centrifugal Casting (SAMCC Process) Liquid + Liquid (Double Centrifugal Casting) See the effects of the present invention below.

In the process ⓒ SAMCC means the liquid plus liquid double centrifugal casting process of the present invention, which is an abbreviation of Spacial Application Material Centrifugal Casting, is a coined word by the present inventors, and thus manufactured by double centrifugal casting as in the present invention. The roll may be called a SAMCC roll (ROLL).

And, ⓐ, ⓑ shows a hardfacing process and a CPC process according to the prior art.

Figure 7 shows the hardness of the roll by the double centrifugal casting of the Table 1 © process according to the present invention, the roll (ⓐ) by the conventional hard facing process and the roll (ⓑ) by the CPC process by position, that is, Figure 5a And as shown in Figure 5b picture is shown the hardness according to the position (distance) of the roll in the state that the inner layer 12 and the outer layer 11 are in contact with each other.

As shown in Table 1 and FIG. In the process ⓐ and ⓑ according to the prior art, the hardness of the inner layer region and the outer layer region changes drastically, and thus the bonding force between the inner layer and the outer layer is very weak, while the liquid plus liquid double centrifugal casting according to the present invention is performed. It can be seen that the boundary of the roll is relatively inclined, and the durability of the outer layer is improved due to the high surface hardness of the outer layer.

On the other hand, in addition to the thick welding hardfacing transfer transformer roll used in steelmaking in steelmaking, for example, the outer layer 11 of the liquid in consideration of the wear resistance and heat resistance of high-temperature wear resistant materials, such as high chrome or hot wear-resistant tool steel, etc. First centrifugal injection, and the inner layer 12, the secondary material, is a chromium molybdenum alloy, the impact resistant material, selected by SCM system or stainless steel type, and injected into the double centrifugal casting process of the present invention, and both sides of the shaft hole When the part is machined and the bearing is mounted and manufactured as a feed roll, it can be replaced by a transroll for general or hardfacing transfer.

As such, it will be understood that the dual centrifugal casting of the present invention can be modified in many ways by selective implementation of various materials depending on the purpose of application.

As can be seen from the above description, according to the performance guide roll manufactured using the double centrifugal casting of the present invention, when the production guide roller is installed in the continuous casting machine, the outer layer has excellent heat resistance and corrosion resistance to the cast steel, The inner layer has excellent impact resistance and mechanical strength due to pressure or stress, and the interlayer material between the outer layer and the inner layer is diffused and mixed so that the durability of the roller is increased. The productivity can be greatly improved.

In addition, by arbitrarily selecting different materials according to double centrifugal casting, there is an advantage that it can be used for various purposes as needed.

Claims (8)

In the performance guide roll comprising a tubular outer layer and the inner layer provided on the inner surface of the outer layer, The outer layer is formed by preheating the centrifugal mold, applying a coating agent to the inside of the centrifugal mold, and injecting a molten metal for the outer layer while rotating the centrifugal mold. The inner layer is formed on the inner surface of the outer layer by checking the temperature of the outer layer formed in the centrifugal mold and then injecting a molten metal for the inner layer, using a liquid plus liquid double centrifugal casting process. Manufactured guide rolls. The method according to claim 1, Check the temperature of the outer layer to inject the molten metal for the inner layer when the temperature of the outer layer is lower than 10 ℃ to 200 ℃ from the liquidus temperature inherent to the metal by injecting the outer layer and the inner A play guide roll manufactured using a liquid plus liquid double centrifugal casting process, wherein the molten metal diffuses from each other at a boundary of a layer. The method according to claim 1, After forming the inner layer, the temperature of the inner layer is checked and cooling / heating is performed in a range of ± 50 ° C. of the solidus temperature inherent to the metal, so that the outer layer and the inner layer are formed at the boundary between the outer layer and the inner layer. A performance guide roll manufactured by using a liquid plus liquid double centrifugal casting process, wherein molten metals are diffused from each other. The method according to claim 1, The outer layer is a martensite-based stainless steel, and the inner layer is a chromium-molybdenum steel (SCM) or nickel-chromium-molybdenum steel (SNCM) characterized in that the liquid plus liquid double centrifugal Performance guide rolls manufactured using the casting process. The method according to claim 1, The outer layer is a wear-resistant steel chromium steel or chromium-molybdenum steel (SCM) or nickel-chromium-molybdenum steel (SNCM), the inner layer is a liquid plus liquid double centrifugal casting, characterized in that using stainless steel Performance guide rolls manufactured using the process. delete The method according to claim 1, The coating agent may be selected from any one of a release agent and a surfactant, including a silica-based (SILICA), zirconia, or a release guide prepared using a liquid plus liquid double centrifugal casting process, characterized in that a release coating agent is used. role. A transfer transformer roll, comprising: bearings are mounted at both ends of a shaft hole of a play guide roll manufactured by the liquid plus liquid double centrifugal casting process according to any one of claims 1 to 5.

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