JP2007050430A - Roll for continuous casting and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make the service life of a roll for continuous casting longer than that of conventional ones by minimizing the unevenness on the surface of a roll body even if the roll is repeatedly used. <P>SOLUTION: The roll body 3 of the roll for continuous casting has a three-layered constitution, in which a 2nd layer 5 is formed on a 1st layer 4, and a 3rd layer 6 is formed on the 2nd layer 5. The 3rd layer 6 is formed of a thin-walled layer having no unevenness on its surface. On the surfaces of the 1st layer 4 and the 2nd layer 5, which are in contact with the inside of the 3rd layer 6 as a thin-walled layer, a plurality of annular hollow parts 7 are formed so as to cross the axial direction of a roll 1 for continuous casting at equal intervals. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a continuous casting roll used for conveying a continuously cast slab in a continuous casting facility, and a method for manufacturing the roll.

  Conventionally, there are many continuous casting roll technologies used to transport slabs continuously cast from molten steel in continuous casting equipment. For example, Patent Document 1 discloses a continuous casting roll in which a plurality of annular slit grooves are provided in the circumferential direction on the outer peripheral surface of a roll body. The surface of the roll body of a continuous casting roll is cracked by thermal stress due to repeated expansion and contraction when it is in contact with the heated slab. By providing the slit groove, the strain due to expansion at the time of slab contact is absorbed, and the life of the continuous casting roll is extended.

  When the roll for continuous casting described in Patent Document 1 is used, cracks on the surface of the roll body are prevented, but this time, stress is concentrated at the groove bottom of the slit groove when absorbing thermal expansion by the slit groove. As a result, the problem of cracking occurs. Therefore, in the continuous casting roll of Patent Document 2, the shape of the slit groove provided on the outer peripheral surface of the roll body portion is a curved cavity having a high aspect ratio (depth / width) and a radius of curvature larger than the slit width at the tip. The shape has. This prevents stress concentration on the tip of the slit groove and prevents cracks not only on the surface of the roll body but also on the bottom of the slit groove, thereby further extending the life of the continuous casting roll. It is possible.

Japanese Patent Laid-Open No. 4-71762 JP 2004-195517 A

  However, in the continuous casting rolls described in Patent Documents 1 and 2, since the slit groove is provided on the outer peripheral surface of the roll body, there are irregularities on the surface of the roll body, and various problems resulting from it. Will occur. For example, the uneven shape on the surface of the roll body may be transferred to the slab during conveyance. In addition, since the uneven shape is easy to bite foreign matter, flaws are likely to occur on the surface of the slab. Furthermore, since the uneven shape directly contacts the slab, the groove width for each slit groove is caused by repeated use, and the uneven shape itself may be deformed. Furthermore, since only the concavo-convex convex portion contacts the slab, it wears out quickly.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems. The continuous casting roll has a continuous casting roll that has a longer life than conventional ones by minimizing the uneven shape on the surface of the roll body even after repeated use. It is an object of the present invention to provide a casting roll and a manufacturing method thereof.

  In order to solve the above-described problems, according to the present invention, a continuous casting roll comprising a plurality of layers is provided, wherein a thin layer having no irregularities is formed on the outermost periphery of the roll body, A continuous casting roll is provided in which a plurality of annular cavities are provided in the axial direction of the roll on the surface side of the inner layer in contact with the thin layer.

  As described above, in the present invention, since the outermost periphery of the roll is a thin layer having no unevenness on the surface, the unevenness is not first transferred to the slab during conveyance. The thermal stress due to repeated thermal expansion and contraction can be absorbed in the cavity. In addition, even if stress is concentrated from the outermost periphery of the cavity part after repeated use, the outermost periphery is a thin layer, so that micro cracks can occur in this part and absorb the stress. It is.

  In the continuous casting roll, an annular notch may be formed on the surface of the outermost thin layer corresponding to the hollow portion.

  In the continuous casting roll, a spiral cavity may be provided instead of the plurality of annular cavities.

  According to the present invention, as the above-described method for producing a continuous casting roll, there is provided a first method for producing a continuous casting roll, wherein a plurality of annular grooves or spiral grooves are formed on the outer peripheral surface of the roll body. A continuous casting roll, comprising: a step; a second step of forming a thin layer on the outer peripheral surface; and a third step of polishing the outer peripheral surface of the thin layer thereafter. A method is provided.

  The second step includes a step of forming a thin layer of a material along the axial direction of the roll with respect to the outer peripheral surface of the roll body, and then rotating the roll body at a predetermined angle. And the process may be repeated.

  In the second step, the material to be a thin layer is formed in an annular shape along the circumferential direction of the roll or in a spiral shape with the axial direction of the roll as an axis on the outer peripheral surface of the roll body. Also good.

  According to the present invention, an annular cavity corresponding to a conventional slit groove is provided under the outermost thin layer of the roll body, so that the uneven shape on the surface of the roll body is minimized and continuous casting is performed. It is possible to extend the service life of the roll for use.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the present specification and drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a front view of a continuous casting roll 1 according to an embodiment of the present invention. FIG. 2 is a partial cross-sectional view of the continuous casting roll 1. As shown in FIGS. 1 and 2, the continuous casting roll 1 has a configuration in which a cylindrical roll body 3 is formed around a shaft 2. In this embodiment, the roll body 3 has a diameter of about 400 mm and an axial length of about 2500 mm. The roll body 3 has a three-layer structure in which the second layer 5 is formed on the first layer 4 disposed on the innermost side, and the third layer 6 is further formed thereon. The outermost third layer 6 is a very thin layer with no irregularities on the surface, and in this embodiment, the thickness is, for example, about 4.5 mm. In this embodiment, for example, SNCM 21 is used as the material of the first layer 4. As a material of the second layer 5, for example, Cr—Ni—low alloy or the like is used. As the material of the third layer 6, for example, 0.1C-13Cr-Ni-Mo is used.

  As shown in FIGS. 2 and 3, the first layer 4 and the second layer 5 are regarded as one layer as an inner layer in contact with the third layer 6 of the roll body 3, and an annular surface is formed on the surface side thereof. A plurality of hollow portions 7 are provided in the axial direction of the roll. In this embodiment, about 80 annular cavities 7 are provided in the roll body 3 with a pitch P of 20 mm, for example, at equal intervals. The depth L of the cavity 7 is set to about 15.5 mm from the third layer 6, for example. The width D of the cavity 7 is about 4 mm. FIG. 3 is an enlarged cross-sectional view of the vicinity of the cavity 7. As shown in FIG. 3, in this embodiment, the annular cavity 7 penetrates the second layer 5 and is the innermost first. It is formed so as to reach the layer 4. However, the annular cavity 7 may be formed only in the second layer 5. The bottom surface of the cavity portion 7 is formed into a curved surface in order to prevent stress concentration.

  The continuous casting roll 1 according to the present embodiment has the above-described configuration, and since there is no uneven shape on the surface of the roll body 3, when transporting a slab continuously cast from molten steel, , Unevenness is not transferred to the slab surface. Moreover, since it does not have an uneven shape, there is little possibility of biting in foreign matter, and the shape of the surface of the roll body 3 is unlikely to change even after repeated use. Moreover, since the surface of the roll body 3 does not have an uneven shape and the entire outer peripheral surface contacts the slab, the wear rate is slower than in the prior art. Further, since the hollow portion 7 is not exposed, there is no accumulation of residues and particles, and therefore there is no risk of corrosion than in the past.

  Furthermore, by providing the annular cavity 7, thermal stress due to repeated thermal expansion and contraction caused by contact with the slab can be absorbed by the cavity 7. This has the effect of extending the life of the continuous casting roll 1. Further, when the stress is concentrated from the outermost periphery of the cavity portion 7 after repeated use, the third layer on the outermost periphery formed on the annular cavity portion 7 as shown in FIG. 6, a minute crack 8 reaching the cavity 7 is generated. This is because the outermost third layer 6 is formed as a very thin layer, and a crack is generated in this portion, so that stress can be absorbed.

  Since the crack 8 generated in this way is very small, the uneven shape formed on the surface of the continuous casting roll 1 is minimized, and compared with the conventional case when transporting a slab continuously cast from molten steel. Then, there is little transfer of unevenness to the slab. In addition, since the uneven shape is minimal, there is less risk of biting in foreign matter. In addition, since the uneven shape is minimal, the shape of the surface of the roll body 3 hardly changes even after repeated use. Further, since the uneven shape on the surface of the roll body 3 is minimal, almost the entire outer peripheral surface is in contact with the slab, so that the wear rate is slow. Further, since the crack 8 is very small, the cavity 7 is hardly exposed and there is no possibility of corrosion.

  As a modified embodiment, as shown in FIG. 5, a minute notch 9 may be formed on the surface of the third layer 6 corresponding to the annular cavity 7. As a result, as shown in FIG. 6, when stress is concentrated from the outermost periphery of the cavity 7, it is possible to generate a crack 8 that reaches the cavity 7 from the position where the notch 9 is formed. That is, since the crack 8 can be generated at a predetermined position, the crack 8 reaching the cavity 7 can be realized corresponding to all the cavities 7 without being biased.

  Further, in this embodiment, the case where a plurality of annular cavities 7 are provided in the axial direction of the continuous casting roll 1 has been described. However, the cavity 7 has a spiral axis as the axis of the continuous casting roll 1. It may be formed as a continuous or discontinuous spiral cavity.

  In this embodiment, the roll body 3 is configured such that the second layer 5 is formed on the innermost first layer 4 and further the third layer 6 is formed thereon. However, as another embodiment, as shown in FIG. 7, the configuration of the roll body portion 3 is arranged on the first layer 4 arranged on the innermost side. Alternatively, a two-layer structure in which the thin layer 6 is formed may be used. Also in the case of such a two-layer roll body 3, the same effect as in the case of the three-layer roll body 3 can be obtained.

  The continuous casting roll 1 having the above-described configuration can be manufactured, for example, by the following method.

  First, a plurality of annular grooves 7 or spiral grooves are formed on the outer peripheral surface of the roll body 3 where the first layer 4 and the second layer 5 are formed. This groove may be formed by known machining or by ionizing the first layer 4 and the second layer 5 formed in the roll body 3 as described in Patent Document 2 above. It may be formed by dissolving.

  As shown in FIG. 8, a thin layer material is formed along the axial direction of the continuous casting roll 1 with respect to the outer peripheral surface of the second layer 5 in which a plurality of annular grooves 7 or spiral grooves are formed. For example, the third layer 6a is formed in a strip shape by submerged arc welding using the welding electrode 11 while supplying chromium-molybdenum steel as a flux from the flux supply unit 10.

  Next, as shown in FIG. 9, after the first strip-like third layer 6a is formed from one end to the other end in the axial direction of the continuous casting roll 1 by submerged arc welding, the roll body portion is formed. 3 is rotated at a predetermined angle. This predetermined angle is an angle determined by multiplying the ratio of the circumferential length of the roll body 3 and the length of the arc portion of the belt-like third layer 6a by 360 degrees. Thereafter, as shown in FIG. 10, the flux supply unit 10 is applied along the axial direction of the continuous casting roll 1 to the outer peripheral surface of the second layer 5 of the rotated roll body 3 as shown in FIG. The third layer 6b is formed in a band shape by submerged arc welding using the welding electrode 11 while supplying the flux from.

  As a result, the second strip-shaped third layer 6b is formed adjacent to the first strip-shaped third layer 6a. In this way, the step of forming the material of the thin layer 6 in a strip shape until the entire outer peripheral surface of the second layer 5 of the roll barrel portion 3 is covered with the plurality of strip-like third layers 6; The step of rotating the part 3 at a predetermined angle is repeated.

  When the thin third layer 6 is formed on the outermost peripheral surface so as to cover the entire outer peripheral surface of the second layer 5 of the roll body 3, the outer surface of the outermost peripheral surface is polished so that the surface has no uneven shape. Finish.

  In the manufacturing method according to this embodiment, when the third layer 6 is formed on the outer peripheral surface of the roll body 3 on which the first layer 4 and the second layer 5 are formed, the continuous casting roll 1 is used. Although the case where the third layer 6a is formed in a strip shape along the axial direction is described, as shown in FIG. 11, the third layer 6c, 6d,... It may be formed in an annular shape along the circumferential direction of the roll 1 as described above. In the manufacturing method according to another embodiment, when the third layer 6 is formed, the flux supply unit 10 is moved in the axial direction of the roll 1 while rotating the roll body 3 as shown in FIG. The third layer 6e may be formed in a spiral shape with the axial direction of the roll 1 as an axis.

  According to the above embodiment, the continuous casting roll 1 having the above-described configuration can be easily manufactured by using only simple machining, and can be manufactured at low cost.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, this invention is not limited to the example which concerns. It is obvious for those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs to.

  The present invention is useful for a continuous casting roll for conveying a continuously cast slab in a continuous casting facility.

It is a front view of the roll for continuous casting which concerns on embodiment of this invention. It is a fragmentary sectional view along the axial direction of the roll for continuous casting which concerns on embodiment of this invention. It is the figure which expanded sectional drawing along the axial direction of the roll for continuous casting which concerns on embodiment of this invention in the cavity part vicinity. It is the figure which expanded sectional drawing along the axial direction of the roll for continuous casting which concerns on embodiment of this invention in the cavity part vicinity. It is the figure which expanded sectional drawing along the axial direction of the roll for continuous casting which concerns on embodiment of this invention in the cavity part vicinity. It is the figure which expanded sectional drawing along the axial direction of the roll for continuous casting which concerns on embodiment of this invention in the cavity part vicinity. It is a fragmentary sectional view along the axial direction of the roll for continuous casting which concerns on another embodiment of this invention. It is a figure explaining the manufacturing method of the roll for continuous casting which concerns on embodiment of this invention. It is a figure explaining the manufacturing method of the roll for continuous casting which concerns on embodiment of this invention. It is a figure explaining the manufacturing method of the roll for continuous casting which concerns on embodiment of this invention. It is a figure explaining the manufacturing method of the roll for continuous casting which concerns on another embodiment of this invention. It is a figure explaining the manufacturing method of the roll for continuous casting which concerns on another embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Roll for continuous casting 2 Shaft part 3 Roll body part 4 1st layer 5 2nd layer 6, 6a, 6b, 6c, 6d, 6e 3rd layer 7 Groove 8 Crack 9 Notch 10 Flux supply part 11 Welding electrode

Claims (6)

A roll for continuous casting composed of a plurality of layers,
On the outermost periphery of the roll body, a thin layer with no irregularities is formed
Further, a continuous casting roll characterized in that a plurality of annular cavities are provided in the axial direction of the roll on the surface side of the inner layer in contact with the thin layer. 2. The continuous casting roll according to claim 1, wherein an annular notch is formed on a surface of the outermost thin layer corresponding to the hollow portion. The continuous casting roll according to claim 1 or 2, wherein a spiral cavity is provided instead of the plurality of annular cavities. A method for producing a continuous casting roll comprising:
A first step of forming a plurality of annular grooves or spiral grooves on the outer peripheral surface of the roll body,
A second step of forming a thin layer on the outer peripheral surface;
Thereafter, a third step of polishing the outer peripheral surface of the thin layer, a method for producing a continuous casting roll. The second step includes
Forming a thin layer of a material in a strip shape along the axial direction of the roll with respect to the outer peripheral surface of the roll body portion;
5. The method of manufacturing a continuous casting roll according to claim 4, wherein the step of rotating the roll body at a predetermined angle is repeated. The second step includes
Forming a thin layer material in a ring shape along the circumferential direction of the roll or in a spiral shape with the axial direction of the roll as an axis with respect to the outer peripheral surface of the roll body portion, The manufacturing method of the roll for continuous casting of Claim 4.

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