KR100880161B1 - Roll manufactured by vertical or horizontal centrifugal casting and the method for manufactured the same - Google Patents

Abstract

A roll manufactured by centrifugal casting is provided to obtain articles having relatively excellent wear resistance by relatively maintaining a rapid cooling effect during the manufacture of the roll, thereby obtaining fine and compact casting structure in the roll, and a method for manufacturing the roll is provided. A roll manufactured by centrifugal casting comprises a first layer(2) and a second layer(4). The first layer is formed by centrifugal casting. The first layer is formed by injecting a composition under the liquid-phase state of 1300 to 1600 deg.C. The composition comprises 0.6 to 0.9 wt.% of C, 0.1 to 1.0 wt.% of Si, 0.1 to 1.0 wt.% of Mn, 5 to 10 wt.% of Cr, 2 to 8 wt.% of W, 1 to 5 wt.% of Mo, 0.1 to 5 wt.% of V, 0.1 to 3 wt.% of Ni, 0.1 to 5 wt.% of Co, 0.1 to 4 wt.% of Nb, and the balance of Fe and other inevitable impurities. The second layer is formed by joining the impact modifier with the first layer after injecting an impact modifier into a hollow part of the first layer in a temperature range lower than a characteristic liquidus line temperature. He impact modifier is one selected from SS400, SCM440, SNCM, and SKD61.

Description

Roll manufactured by Vertical or Horizontal Centrifugal Casting and the Method for manufactured the Same}

The present invention relates to a roll and roll manufacturing method by vertical or horizontal centrifugal casting, more specifically, having an outer layer and / or an inner layer by vertical or horizontal centrifugal casting, for example wire rod rolling, pinch roll, A roll, such as a guide roll, and its manufacturing method.

In general, steel is a steelmaking process, which is a basic process of producing iron by melting iron ore through blast furnaces, steelmaking process of removing impurities from steel to make steel, and a regeneration process in which liquid iron becomes a solid in a predetermined shape. It is produced by four processes of hot rolling process, from which steel is started to steel or wire.

In the steel manufacturing process, the playing process is a process of continuously solidifying molten steel into a cast of a constant shape through a continuous casting machine is shown in FIG.

The continuous casting machine forms a ladle (1) for accommodating the molten steel (2), a tundish (3, tundish) for temporarily storing the molten steel received from the ladle (1), and forms the molten steel (2) in a predetermined shape. The mold 4 and the performance guide roller 10a which guides the cast piece 2a drawn out from the mold 4 are included. Cast steel (2a) is divided into slab (bloom), bloom (billet), etc. according to the type of production, the wire rod is usually used to cut to a constant length.

Currently, products are produced by hot rolling in the case of rods or wires produced by special steel manufacturers, and in the case of intermediate rolling, the temperature is very high, around 1000 ° C. The rolling roll used in the rolling should have high abrasion resistance even at high temperatures, and should be used in processing, so that a material which requires proper workability at the same time should be used. In the case of the wire rod which is mainly used, the casting roll which W-Cr-Mo-V etc. contained large quantity (20 weight% or more) is used, and most are produced by sand casting.

In recent years, with the rapid increase in cost of alloyed iron and the like, in the case of such a hot rolled wire rod, the development of alternative materials for cost reduction is urgently required as the cost of material cost increases. Since the addition of a certain amount of alloy to prevent abrasion resistance deterioration is essential, it is not easy to develop alternative materials. Moreover, since the wire rod is produced by sand casting, the size of crystal grains and carbides is relatively coarse and the structure is not dense, so that the improvement of the metal structure is absolutely required.

Accordingly, it is an object of the present invention to provide a roll and roll manufacturing method by vertical or horizontal centrifugal casting, in which the manufacturing cost is not only lower than the conventional technology but also the life can be improved, and the structure is dense.

The above object is formed by centrifugal casting according to one embodiment of the present invention, wherein C: 0.6 to 0.9% by weight, Si: 0.1 to 1.0% by weight, Mn: 0.1 to 1.0% by weight, Cr: 5 to 10 wt%, W: 2-8 wt%, Mo: 1-5 wt%, V: 0.1-5 wt%, Ni: 0.1-3 wt%, Co: 0.1-5 wt%, Nb: 0.1-4 wt% A first layer formed by injecting a composition consisting of%, the balance Fe and other unavoidable impurities under a liquid state of 1300 ° C to 1600 ° C,

Impact cushioning material provided with any one of SS400, SCM440, SNCM, SKD61 is injected into the hollow portion of the first layer in a range lower than the intrinsic liquidus temperature, and then combined with the first layer to form a second layer It can be achieved by a roll produced by centrifugal casting.

The first layer and the second layer is characterized in that the forging process.

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According to the roll and roll manufacturing method by the vertical or horizontal centrifugal casting according to the present invention as described above, the manufacturing cost is reduced by 40% reduction compared to the conventional roll manufacturing cost, and the defect (bubble) in the manufactured roll The incidence can be significantly reduced, the tissue can be denser, the bonding rate of the first layer and the second layer can be increased, and the wear and impact resistance can be improved, thereby improving the lifespan.

As described above, since rolls such as wire rod rolls according to the present invention are manufactured in a circular shape, they are manufactured by centrifugal casting as compared with conventional sand casting, and thus have a relatively quenching effect, so that the casting structure is fine and dense. It is possible to obtain a product having excellent wear resistance. In addition, in the case of wire rod roll, since it is discarded after only using it from the 1st layer to a certain depth, the 1st layer (outer layer) is a heat resistant and abrasion resistant material at the time of centrifugal casting, and the 2nd layer (inner layer) In the case of using an inexpensive material, the manufacturing cost is low, and the impact resistance can be improved, thereby improving the impact resistance.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2a and 2b is a view showing a steel wire roll roll and a non-ferrous wire roll roll produced in accordance with the present invention, respectively.

2A and 2B, the first layer (2, outer layer) is in weight percent according to the present invention, C: 0.5-2.8, Si: 0.5-1.5, Mn: 0.5-1.5, Cr: 3-10, W : 3-15, Mo: 1-7, V: 0.5-7, Ni: 0.1-3, Ti: 0.1-2, Co: 0.1-10, remainder Fe, and other unavoidable impurities. The first layer having such a composition has a long life Ti being added to a conventional heat-based (W-Cr-Mo-V) material, so that the life of the roll produced is about 1.3 to 1.5 times that of the conventional heat-based material. Can be improved.

The first layer 2 is also in weight percent, C: 0.6 to 1.4, Si: 0.1 to 1.0, Mn: 0.1 to 1.0, Cr: 5 to 10, W: 2 to 8, Mo: 1 to 5, V: 0.1-5, Ni: 0.1-3, Co: 0.1-5, Nb: 0.1-4 remainder Fe, and other inevitable impurities.

The first layer 2 having the composition as described above is melted at a temperature of 1300 to 1600 ° C, injected under a liquid state, and cast as a hollow body having an outer diameter and an inner diameter of a predetermined size by centrifugal casting. At this time, the centrifugal casting method used may be a horizontal or vertical centrifugal casting method.

In the method for producing a roll as described above, first, the centrifugal mold is preheated at a predetermined temperature, and a coating agent for release purpose is spray applied to the inside of the centrifugal mold. As the coating agent for the release purpose, a release agent such as silica (SILICA), zirconia, and a surfactant may be selected or used in combination. While rotating the centrifugal mold at high speed, the liquid metal of the composition as described above for the liquid phase first layer 2 is injected into the centrifugal mold to form the first layer 2. While the material of the first layer 2 of the composition as described above is brought into close contact with the inner surface of the centrifugal mold by the centrifugal force with an even thickness and density, a tubular first layer 2 having a predetermined thickness is formed.

As such, the first layer 2 formed in a tubular shape may optionally be subjected to forging molding such as free forging, die forging, ring mill, or the like. By forging by this, the 1st layer 2 shape | molded as a roll becomes denser in structure, and can be used as a rolling roll, a pinch roll, a guide roller, a feed roll, etc.

On the other hand, according to the present invention, it may be formed as a double-structured roll in which the second layer 4 is provided in the first layer 2 before the forging molding process as shown in FIG. 2. Thus, in the case where the second layer 4 is provided in the first layer 2, after checking the temperature of the first layer 2 cast by the centrifugal casting method as described above, the shock-absorbing material, That is, the material of the second layer 4 of inexpensive material such as SS400, SCM440, SNCM, SKD61, DCI, etc. is melted at a temperature of 1300 to 1600 ° C and injected into the first layer 2 in the liquid phase, and further, by centrifugal casting. By shaping | molding, a hollow part is formed in a center part.

The material for the second layer 4 is melted into the first layer 2 at a suitable timing before the first layer 2, which is formed into a tubular body by centrifugal casting, completely cools down as described above. It is injected into the liquid phase. This is because different materials are exchanged and kneaded at the interface of the contact section between the inner surface of the first layer 2 and the outer surface of the second layer 4, so that the mutual interaction of the first layer 2 and the second layer 4 is achieved. It is for improving the bonding strength.

The time point at which the material for the second layer 4 is injected into the liquid phase in the molten state is different depending on the material of the first layer 2, but is lower than the inherent LIQUIDUS LINE temperature of each selected material. It is preferred to inject the material for the second layer 4 in.

The liquidus line represents the temperature at which the liquid metal begins to solidify, i.e., after completion of the outer layer forming process, the material selected as the first layer 2 slowly cools down and passes over the liquidus temperature to eventually complete solidification. It falls below the temperature at which the second layer 4 must be injected before the solid phase is achieved. If inert gas or nitrogen gas is injected during this process, the joint surface and bonding strength are increased.

3 is a graph showing the relationship between the boundary distance and the hardness of the two-layer structure made according to the present invention as described above. As can be seen from FIG. 3, the hardness of the inner layer, ie the second layer 4, is low, and the hardness rises in the boundary region with the first layer 2, so that in the outer layer, ie the first layer 1, It can be seen that the hardness gradually increases. Accordingly, the first layer 2 constituting the outer layer can be improved in abrasion resistance by having a higher hardness, and the inner layer having a lower hardness, that is, the second layer 4, can reduce the impact. Impact properties can be improved.

As mentioned above, the roll according to the invention in the dual structure of the first layer 2 and the second layer 4 is optionally provided to compact the structure of the first layer 2 and the second layer 4. Forging molding processing as described above may also be made.

Although the present invention has been described in connection with the above-mentioned preferred embodiments, it will be readily apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the invention, all such modifications and modifications being attached It is obvious that the claims belong to the claims.

1 is a diagram of a general playing process.

2a and 2b is a view showing a steel wire roll roll and a non-ferrous wire roll roll produced in accordance with the present invention, respectively.

3 is a graph showing the relationship between the boundary distance and the hardness of the two-layer structure made according to the present invention as described above.

<Description of Symbols for Main Parts of Drawings>

2: first layer 4: second layer

Claims (9)

delete It is formed by centrifugal casting, C: 0.6 to 0.9% by weight, Si: 0.1 to 1.0% by weight, Mn: 0.1 to 1.0% by weight, Cr: 5 to 10% by weight, W: 2 to 8% by weight, Mo: 1 A composition consisting of -5% by weight, V: 0.1-5% by weight, Ni: 0.1-3% by weight, Co: 0.1-5% by weight, Nb: 0.1-4% by weight, balance Fe and other unavoidable impurities is contained at 1300 ° C. A first layer formed by injection under a liquid state at 1600 ° C, Impact cushioning material provided with any one of SS400, SCM440, SNCM, SKD61 is injected into the hollow portion of the first layer in a range lower than the intrinsic liquidus temperature, and then combined with the first layer to form a second layer Rolls produced by centrifugal casting. delete delete The method of claim 2, The first layer and the second layer is a roll produced by centrifugal casting, characterized in that the forging process. delete delete delete delete

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