KR20100006732A - Apparatus and method for roll in twin roll strip casting machine - Google Patents

Abstract

PURPOSE: A casting roll of a twin roll type strip caster and a manufacturing method thereof are provided to prevent edge build-up phenomenon due to the difference of solidification ability in the casting. CONSTITUTION: A casting roll of a twin roll type strip caster comprises a base coating layer(8) and a hard coating layer(9). The base coating layer has an inclined part whose thickness is getting thinner when getting closer to the center part from a side edge(12). The hard coating layer is coated on the inclined surface of the basic coating layer. A tilt angle(θ) of the hard coating layer and the base coating layer is 1.0~30.0° range. The hardness of the hard coating layer is the Hv 300~600 range. The hard coating layer comprises the nickel boron and nickel chrome. The base coating layer comprises the material with a superior heat impact property.

Description

Casting roll of twin roll sheet casting machine and its manufacturing method {apparatus and method for roll in twin roll strip casting machine}

The present invention is a pair of casting roll (1), and the edge dam (2) which is installed on both left and right sides thereof and the molten steel pool (4) formed between the casting roll (1) and the edge dam (2) In the casting roll of a twin roll sheet casting machine which casts the cast steel by rotating the casting roll (1) in the interlocking direction with an immersion nozzle (3) for supplying molten steel to the molten steel, it prevents the occurrence of cracks and has a long life (1) and its manufacturing method.

The twin-roll thin plate casting process is a method of manufacturing a thin plate having a thin thickness of 10 mm or less by pouring molten steel into both casting rolls 1 engaged with each other to coagulate and applying a certain amount of hot deformation.

As shown in FIG. 1, a twin roll sheet casting machine employed in the sheet casting process as described above is turned between a pair of casting rolls 1 cooled by cooling water and an edge dam 2 attached to both sides thereof. In the dish 5, a molten steel pool 4 is formed by molten steel supplied through the immersion nozzle 3, and the casting rolls 1 are rotated in opposite directions to contact the rolls and into the casting roll 1. Rapidly solidify molten steel deprived of heat to produce cast steel.

Since the molten steel supplied between the rotating casting rolls 1 is sealed by the edge dam 2, close contact between the edge dam 2 and the side of the casting roll 1 is very important, and the edge dam 2 is a rotating casting. Since the roller 1 adheres to the side of the roll 1 and is frictionally worn, the casting roll 1 is coated to maintain the molten steel for a long time and provide stable wear. This side coating is very important in terms of productivity.

The cylindrical surface of the casting roll (1) directly contacting the molten steel is preferably a coating layer made of a material having excellent thermal shock, but the casting roll side portion (7) contacting the edge dam (2) requires a high hardness material because it requires abrasion resistance as well as thermal shock resistance. Prefer If the hardness is low, the shape changes due to the edge dam (2) and frictional wear, and the molten steel sealability is poor, resulting in poor cast edge shape resulting in poor error rate or low casting stability. And since peeling easily occurs, there is a problem that the life of the casting roll 1 is shortened.

However, since the thermal shock resistance and the high hardness have mutually opposite aspects, it is not easy to implement both of them materially. Increasing the hardness of the side coating in order to increase the wear resistance of the side of the casting roll (1), which is in contact with the edge dam (2), the thermal conductivity and elongation is lower than the basic coating layer having excellent thermal shock coating on the casting roll cylindrical portion (6). Accordingly, when the coating layer is in contact with the molten steel, cracks occur in the edge 13 coating layer due to the difference in thermal expansion and elongation, and when casting is continued, the cracks grow and the crack propagates to the surface coating layer and the inside of the sleeve 10 under the coating layer. do. In order to solve this problem, various methods have been proposed.

Representative methods include the method of securing the wear resistance and thermal shock resistance by limiting the hardness (Patent Publication No. 2000-0047516), and the material that is in contact with molten steel is selected from the material having excellent internal rigidity, and the material of the inner material is selected from high hardness. A double structure method (Japanese Patent Laid-Open Publication No. 6-126390) and a method of coating the entire edge 12 extending from the casting roll (1) barrel to the casting roll (1) side to prevent peeling and cracking (Japanese Patent Laid-Open Application No. 6-126390). 7-284883).

However, Patent Publication No. 2000-0047516 proposes to attach sus410, 440A 301 630 or high manganese cast steel, nickel-chromium-molybdenum steel, inconel, etc., which are materials of HV300 (250g), but the attachment process is difficult to implement. In addition, the cost is inferior due to high cost, and the double structure method such as Japanese Patent Laid-Open No. 6-126390 uses two materials as side materials, which is complicated and expensive. In the case of Japanese Patent Laid-Open No. 7-284883, which coats the entire edge 12, the edge part 13 of the casting roll 1 barrel is plated with a side plate plating material. There is a problem in that the solidification performance of 13) is lowered, the edge defect of the cast steel is reduced and the error rate is lowered.

The present invention is to improve the wear performance on the side of the casting roll (1) which is the above problem, and to solve the cracks caused by thermal shock, the high hardness coating layer 9 on the side edge portion 13 of the casting roll (1) By applying a difference in thickness so that the edge 12 is thin and gradually thickens toward the shaft 10, it prevents the occurrence of cracks from thermal shock and prevents the cracks from propagating to the inside of the casting roll (1). By prolonging the life of 1), the present invention provides a casting roll 1 of a twin roll sheet casting machine with excellent production efficiency and a method of manufacturing the same.

In the present invention, the shaft 10 and the outer portion of the shaft 10 in the center of the sleeve 10 and the two-roll type sheet casting machine of the base coating layer is formed on the surface and side edge portion 13 of the sleeve (10) In the casting roll,

The casting roll 1 has a base coating layer having an inclined surface that becomes thinner from the side edges 12 toward the center portion, and is coated on the inclined base coating layer surface and has a thickness toward the center portion from the side edges 12. The present invention provides a casting roll for a twin roll sheet caster and a method of manufacturing the same, wherein the cast roll is formed of an inclined high hardness coating layer having a thickened shape.

According to the present invention, the high hardness coating layer 9 formed on the side of the casting roll 1 is inclined to become thicker from the edge 12 toward the shaft 10, and thus the edge 12 of the casting roll 1 having a low thermal conductivity in contact with the molten steel. ) Is thinly coated to facilitate heat diffusion and the shaft 10 side of the casting roll 1 which mainly frictions with the edge dam 2 has a thick coating layer 9 so that the wear resistance is excellent even when used for a long time. As a result, it is possible to obtain an effect of improving operation stability and economic efficiency.

In addition, the high hardness coating layer (9) has a low thermal conductivity to suppress the temperature rise of the edge portion 13 of the casting roll (1), to prevent the edge build-up phenomenon caused by the difference in the solidification performance during casting to provide a cast of excellent quality There is an effect to manufacture.

In the present invention, the shaft 10 and the outer portion of the shaft 10 in the center of the sleeve 10 and the two-roll type sheet casting machine of the base coating layer is formed on the surface and side edge portion 13 of the sleeve (10) In the casting roll,

The casting roll (1) is inclined base coating layer (8) in the form of the thickness becomes thinner toward the center portion from the side edge (12), and is coated on the inclined surface of the base coating layer and the center portion at the side edge (12) The present invention relates to a casting roll for a twin roll sheet caster having a high hardness coating layer (9) having an inclined surface having a thickness that increases in thickness, and the high hardness formed on the side edge portion (13) of the casting roll (1). The hardness of the coating layer 9 is in the range of Hv 300 to 600, and is composed of nickel boron or nickel chromium, the coating layer thickness at the corners 12 is 0.01 to 0.4 mm, and the surface and base of the high hardness coating layer 9 The angle of inclination θ with the surface of the coating layer 8 is in the range of 1 to 30 °, and the basic coating layer is characterized by using a material excellent in thermal shock.

In addition, the present invention is a step of forming a base coating layer (8) on the surface and side edge portion 13 of the casting roll (1) sleeve 10, and the side edge portion 13, the base coating layer is formed at the corner ( 12) forming an inclined surface to narrow the thickness toward the center portion, and forming a high hardness coating layer (9) on the inclined surface of the basic coating layer formed on the side edge portion 13, and the high hardness coating layer To be parallel to the side edge portion 13 and to provide a manufacturing method of the cast roll for a double roll type sheet caster, characterized in that consisting of a high hardness coating layer processing step of processing so as to go from the side edge 12 to the center portion is widened. Done.

Hardness of the high hardness coating layer 9 is limited to within the Hv 300 ~ 600 range. If the Hv is less than 300, the wear resistance is not significantly different from that of nickel, and thus the effect of the present invention cannot be obtained. If the Hv is more than 600, the effect on the wear resistance does not increase any more, but cracking of the coating layer easily occurs. As a result, the durability of the coating layer is reduced.

In addition, the thickness of the edge 12 of the high hardness coating layer 9 is limited to within the range of 0.01 ~ 0.4 mm. If the thickness is 0.01 mm or less, sufficient wear resistance cannot be exhibited, and if the thickness is 0.4 mm or more, the wear resistance is good, but heat is not transferred smoothly, so that the maximum temperature of the edge portion 13 of the casting roll 1 becomes very high. Occurs.

Hereinafter, the present invention will be described in detail with reference to the drawings.

Figure 3 shows the step of forming a high hardness coating layer (9) of the side of the casting roll (1) of the present invention, first to prepare and manufacture a basic coating layer using a material such as nickel on the surface and side of the casting roll (1) One base coating layer is processed such that the coating layer is inclined so that the base coating layer becomes thinner from the edge 12 toward the center portion by using a mechanical process or the like.

Next, a high hardness coating layer 9 manufactured using a material such as nickel boron or nickel chromium having a high hardness on the inclined base coating layer surface is moved from the edge 12 to the center portion by mechanical processing. The hard coating layer 9 is vertically processed to be parallel to the side of the sleeve 10 so as to be thick.

Figure 4 shows the casting roll cross-sectional view when manufacturing the casting roll by the method as shown in Figure 3 above. A shaft is formed inside the casting roll, and a sleeve is formed on the outside, and a base coating layer is coated on the surface and side of the sleeve, and a base coating layer and a hard coating layer on the side form a double coating structure. The base coating layer of the side of the sleeve is characterized in that the thickness becomes thinner toward the center portion and the high hardness coating layer becomes wider toward the center portion.

5 is a model of the high hardness coating layer (9) of the side of the casting roll (1) of the present invention modeled by the conditions of the embodiment to obtain the surface temperature of the casting roll (1) by finite element analysis, X-axis is a casting roll ( 1) The rotation angle and Y axis is the temperature of the edge 12 of the casting roll (1). It can be seen that the high hardness coating layer 9 coated with nickel boron has a very high surface temperature of the edge 12 of the casting roll 1 as the thickness becomes thicker. Therefore, it can be seen that the thickness of the high hardness coating layer 9 of the side edge 12 of the casting roll 1 has a significant effect on the production efficiency.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Casting Roll (1) A steel sheet STS 304 was cast in a thickness of 3.0 mm using a large twin roll sheet casting machine having a diameter of 1250 mm and a width of 1340 mm. Copper 10 is used for the sleeve 10 of the casting roll 1, the base coating layer formed on the surface of the sleeve 10 is a nickel layer of 2 mm thickness, the high hardness coating layer formed on the base coating layer of nickel ( 9) is made of nickel boron and coated from the side edge 12 of the casting roll 1 to the center of the shaft 10 to 37 mm below.

Table 1 shows the results of the characteristics of the casting roll (1) according to the coating conditions.

In Comparative Example 1, the side coating of the casting roll 1 was performed by using a nickel material with a thickness of 2 mm. In Comparative Example 2, the base coating was made with a nickel material with a thickness of 2 mm without inclination and 2 mm by a nickel boron material. The coating was made of high hardness, and in Comparative Examples 3 and 1 to 3, the base coating was made of nickel, and the base coating was inclined through machining, and the base coating layer was made of high hardness coating of nickel boron. After machining vertically to produce a final coating layer. In Comparative Example 3, the thickness of the high hardness coating layer 9 is 0.5 mm at the side edges 12 of the casting roll 1 and 3.5 mm below 37 mm at the edges 12, and Example 1 is the high hardness coating layer 9. The thickness of the roll is 0.05 mm at the side edges 12 of the casting roll 1 and 3.95 mm below 37 mm at the edges 12, and Examples 2 and 3 show the side edges of the casting roll 1 of the high hardness coating layer 9. The thickness of (12) is the same as 0.05 mm, and the edge 12 is different from the casting angle of 37 mm to 1 mm and 2 mm, respectively.

Table 1

The amount of wear was measured by measuring the amount of wear of the coating layer after the casting of 1,000 tons in a micrometer. Cu crack measurement examined the depth of crack propagated into the sleeve 10.

As a result, the comparative example 1 of the prior art had a great amount of abrasion, so that the life of the casting roll 1 was very short, and the comparative example 2 had a very severe crack in the sleeve 10. In the case of Examples 1 to 3 of the present invention, good results were obtained at the wear amount, the cracks in the sleeve 10 and the maximum temperature at the edges 12 of the casting roll 1.

1 is a schematic view showing a typical twin roll sheet casting machine.

Figure 2 is a schematic diagram showing a casting roll of a general twin roll sheet casting machine.

Figure 3 is a schematic diagram showing a method of manufacturing a casting roll of the twin-roll sheet caster of the present invention.

Figure 4 is a vertical cross-sectional view of the casting roll of the twin-roll sheet caster of the present invention.

Figure 5 shows the temperature change of the edge of the casting roll according to the coating conditions of the side of the casting roll.

* Description of the symbols for the main parts of the drawings *

1. Casting Roll 2. Edge Dam

3. Immersion nozzle 4. Molten pool

5. Tundish 6. Casting roll cylinder

7. Casting roll side part 8. Existing coating layer

9. Hard coating layer 10. Sleeve

11.shaft 12.edge

13. Edge portion θ. Angle of inclination

100. Double Roll Sheet Casting Machine

Claims (11)

In the casting roll of the twin-roll type sheet casting machine having a shaft 10 and a sleeve 10 at an outer portion of the shaft 10 and a basic coating layer formed on the surface and side edge portions 13 of the shaft 10. In The casting roll 1 has a base coating layer 8 having an inclined surface that becomes thinner from the side edge 12 to the center portion, and is coated on the base coating layer inclined surface and is moved from the side edge 12 to the center portion. Casting roll for twin roll sheet caster, characterized in that consisting of a high hardness coating layer 19 having an inclined surface in the form of thicker thickness. The method of claim 1, The inclination angle θ formed between the surface of the basic coating layer formed on the side edge portion 13 of the casting roll 1 and the surface of the high hardness coating layer is in a range of 1.0 to 30.0 °. . The method of claim 1, The high hardness coating layer (9) formed on the casting roll (1) side edge portion 13 is a casting roll for a twin roll sheet caster, characterized in that the hardness is Hv 300 ~ 600 range. The method of claim 1, Casting roll (1) The high hardness coating layer (9) formed on the edge 12 of the side edge portion 13 has a thickness of 0.01 ~ 0.4 mm casting roll for a twin roll type cast machine. The method of claim 1, Casting roll (1) The high hardness coating layer (9) formed on the side edge portion 13 is a cast roll for a twin roll sheet caster, characterized in that consisting of nickel boron or nickel chromium. The method of claim 1, The casting roll (1) the base coating layer formed on the side edge portion 13 is a casting roll for a twin roll sheet caster, characterized in that using a material excellent in thermal shock. Forming a basic coating layer (8) on the surface and side edge portions (13) of the casting roll (1) sleeve (10); An inclined surface forming step of forming an inclined surface such that the thickness of the side edge portion 13 on which the basic coating layer is formed is narrowed from the edge 12 toward the center portion; Forming a high hardness coating layer (9) on the inclined surface of the base coating layer formed on the side edge portion (13); The high hardness coating layer surface is parallel to the casting roll side portion 7 and the high hardness coating layer processing step of processing to increase the thickness from the side edge 12 toward the center portion; casting for a double roll type cast machine, characterized in that consisting of Manufacturing method of a roll. The method of claim 7, wherein The inclined surface forming step and the high hardness coating layer processing step is a manufacturing method of a cast roll for a twin roll sheet caster, characterized in that carried out by machining. The method of claim 7, wherein Twin roll type, characterized in that the inclination angle (θ) formed by the surface of the base coating layer and the surface of the high hardness coating layer formed on the side edge portion 13 of the casting roll (1) in the high hardness coating layer processing range of 1.0 ~ 30.0 ° Manufacturing method of casting roll for sheet casting machine. The method of claim 7, wherein In the basic coating layer forming step, the basic coating layer is a manufacturing method of a casting roll for a twin roll sheet caster, characterized in that using a material having excellent thermal shock. The method of claim 7, wherein In the high hardness coating layer forming step, the high hardness coating layer (9) is a method for producing a cast roll for a twin roll sheet caster, characterized in that consisting of high hardness nickel boron or nickel chromium.

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