JP2017213589A - Mandrel, ring roll molding machine using the same, and manufacturing method of ring roll product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mandrel capable of improving wear resistance more inexpensively; and to provide a ring roll molding machine using the same, and a manufacturing method of a ring roll product.SOLUTION: A part of an annular workpiece is clamped between a mandrel 11 arranged on the inner peripheral side of the annular workpiece and a molding roll arranged on the outer peripheral side of the annular workpiece, to thereby thin and enlarge the annular workpiece. The mandrel 11 includes a core member 11A, and an outer ring member 11B disposed in a region to be contacted with the annular workpiece on the outer periphery of the core member 11A, and comprising a die steel or a heat-resistant steel.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a mandrel used in a ring roll method, a ring roll molding machine, and a method of manufacturing a ring roll product manufactured by the ring roll method.

  The ring roll method is to rotate a work piece while pressing a part of the work ring with a mandrel located on the inner circumference side and a forming roll located on the outer circumference side against an annular work piece. It is formed into a thin and large-diameter product (see, for example, Patent Document 1). According to this ring roll method, the material yield at the time of manufacture can be improved, a grooved product can be easily manufactured, and the thickness variation can be extremely reduced.

  Conventionally, the mandrel used in the ring roll method is composed entirely of die steel (JIS SKD61 and its improved steel type), or on the surface of chromium molybdenum steel (SCM material) or nickel chromium molybdenum steel (SNCM material). A material formed with a surface treatment film for improving wear resistance or a material obtained by overlay welding a high hardness material is used. In some cases, die steel may be subjected to a surface treatment such as a surface treatment film or build-up. However, die steel is more expensive than chrome molybdenum steel (SCM) and nickel chrome molybdenum steel (SNCM), and the surface treatment film is very thin. In addition to a significant decrease in performance, the surface treatment costs are high. Therefore, it has been desired to develop a mandrel for use in a ring roll method that is cheaper and has high wear resistance.

Japanese Patent Laying-Open No. 2015-24420

  The present invention has been made based on such a problem, and provides a mandrel that can improve wear resistance at a lower cost, a ring roll molding machine using the mandrel, and a method of manufacturing a ring roll product. For the purpose.

  The mandrel of the present invention is disposed on the inner peripheral side of the annular workpiece, and a part of the annular workpiece is sandwiched between the forming rolls disposed on the outer peripheral side of the annular workpiece, thereby thinning the annular workpiece. The center core member and the outer ring member made of die steel or heat-resistant steel disposed in a region where the annular work abuts on the outer periphery of the core member. is there.

  The ring roll molding machine of the present invention clamps a part of the annular workpiece between a mandrel arranged on the inner circumferential side of the annular workpiece and a molding roll arranged on the outer circumferential side of the annular workpiece. Thus, the diameter of the annular workpiece is increased while being thinned, and the mandrel has the configuration of the present invention.

  The manufacturing method of the ring roll product of this invention manufactures a ring roll product by expanding the diameter while thinning an annular workpiece using the ring roll molding machine of this invention.

  According to the present invention, since the outer ring member made of die steel or heat-resistant steel is disposed on the outer periphery of the core member for the mandrel, the portion where the annular work abuts is made harder by the outer ring member. The core member can be formed of a material that is less expensive than die steel or heat resistant steel. Therefore, it can be made cheap as a whole. Moreover, since the thickness of the outer ring member is thinner than the case where the whole is formed of die steel or heat-resisting steel, the inner ring is easily baked by the mass effect and can be hardened to the inside. Therefore, formation of a surface treatment film or the like can be omitted, and wear resistance can be improved at a low cost. Furthermore, since the inside of the outer ring member can be hardened, when the surface is worn by use, it can be repaired by scraping the surface. Therefore, it can be used for a long time.

It is a figure showing the structure of the principal part of the ring roll molding machine which concerns on one embodiment of this invention. It is a figure showing the structure of the mandrel of the ring roll molding machine shown in FIG.

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

  FIG. 1 shows a configuration of a main part of a ring roll forming machine 10 according to an embodiment of the present invention. 2 shows the configuration of the mandrel 11 of the ring roll molding machine 10 shown in FIG. 1, (A) shows the external configuration, and (B) shows the cross-sectional configuration. This ring roll molding machine 10 includes a part of the annular workpiece W between a mandrel 11 disposed on the inner circumferential side of the annular workpiece W and a molding roll 12 disposed on the outer circumferential side of the annular workpiece W. A ring roll product is manufactured by a ring roll construction method for sandwiching and pressing.

  The mandrel 11 and the forming roll 12 are arranged so that the mandrel 11 and the annular workpiece W rotate along with the rotation of the forming roll 12, and the forming roll 12 has a larger diameter than the mandrel 11. In the ring roll molding machine 10, for example, the outer peripheral surface of the annular workpiece W is pressed against the outer peripheral surface of the molding roll 12, and the outer peripheral surface of the mandrel 11 is pressed against the inner peripheral surface of the annular workpiece W to rotate them. The molding roll 12 and the mandrel 11 are configured to move in a relatively approaching manner. Thereby, the annular work W sandwiched between the forming roll 12 and the mandrel 11 is expanded in diameter while being thinned. The outer peripheral surface shape of the mandrel 11 is formed corresponding to the inner peripheral surface shape of the ring roll product to be manufactured, and the outer peripheral surface shape of the forming roll 12 corresponds to the outer peripheral surface and the width surface shape of the ring roll product to be manufactured. Is formed.

  The mandrel 11 includes a core member 11A and an outer ring member 11B made of die steel or heat-resistant steel disposed in a region where the annular workpiece W abuts on the outer periphery of the core member 11A. If the outer ring member 11B made of die steel or heat-resistant steel is disposed on the outer periphery of the core member 11A, the hardness of the portion with which the annular workpiece W abuts is increased by the outer ring member 11B, and the core member 11A This is because it can be made of a material cheaper than that of die steel, and thus can be made inexpensive as a whole. Moreover, since the thickness of the outer ring member 11B is thinner than the case where the entire mandrel 11 is formed of die steel or heat-resistant steel, the inner ring member 11B is easily baked by the mass effect and can be hardened to the inside. Formation of a treatment film or the like can be omitted. A surface treatment film or the like may be formed on the surface of the outer ring member 11B, and the hardness can be further improved by combining the surface treatment film or the like.

  Furthermore, since the outer ring member 11B can be hardened to the inside, when the surface is worn by use, the surface can be scraped and used again. The die steel is, for example, JIS SKD61 and its improved steel type, and the heat-resistant steel is, for example, JIS SUH and its improved steel type.

  The core member 11A is preferably composed of, for example, a chromium molybdenum steel material (SCM material), a nickel chromium molybdenum steel material (SNCM material), or a general structural rolled steel material (SS material). In addition, when the outer ring member 11B is worn by use, the outer ring member 11B is directly cut off, or depending on the case, the worn outer ring member 11B is removed and the surface of the core member 11A is cut. By changing the inner diameter of the new outer ring member 11B to be small, the core member 11A can be used continuously.

  The minimum thickness of the portion of the outer ring member 11B that contacts the annular workpiece W is preferably, for example, not less than 5 mm and not more than 10 mm. If it is too thick, it cannot be hardened to the inside of the outer ring member 11B, and it is not preferable because it increases the price. If it is too thin, the surface of the outer ring member 11B is scraped and repaired when worn. Because it becomes difficult to do.

  It is preferable that an outer ring inclined portion 11C that is inclined so that the inner diameter gradually increases is provided at one end portion in the length direction on the inner periphery of the outer ring member 11B. Further, on the outer periphery of the core member 11A, a core inclined portion 11D that is inclined so that the outer diameter gradually increases corresponding to the outer ring inclined portion 11C at the position where the outer ring member 11B is disposed is provided. It is preferable. These are used to position the outer ring member 11B when the outer ring member 11B is disposed on the outer periphery of the core member 11A by fitting the outer ring member 11B from one end of the core member 11A. Is. Specifically, the core member 11A is inserted into the outer ring member 11B from the outer ring inclined portion 11C side with the smaller outer diameter as a head, and the outer ring inclined portion 11C and the core inclined portion 11D Positioning is performed by moving it until it comes into contact.

  The reason why the positioning portions of the outer ring member 11B and the core member 11A are inclined rather than stepped is that stress is concentrated at the corners and cracks may occur if the steps are made stepped. The core inclined portion 11D and the adjacent side core inclined portion 11D having a smaller outer diameter are partially hardened by, for example, frame hardening or induction hardening to increase the hardness. A hardness region may be formed. It is because generation | occurrence | production of a crack can be suppressed more.

  The outer ring member 11B is preferably disposed on the core member 11A, for example, in a heated and expanded state, and fixed to the core member 11A by contraction due to cooling. For example, the inner diameter of the outer ring member 11B and the outer diameter of the middle core member 11A before the outer ring member 11B is disposed on the middle core member 11A are within the range of 0.04 mm to 0.06 mm. Is preferably larger than the inner diameter of the outer ring member 11B. Further, when there is a looseness between the outer ring member 11B and the core member 11A and the outer ring member 11B rotates with respect to the core member 11A, a fixing member such as a fixing pin (not shown) is used. It may be fixed.

  For example, the ring roll forming machine 10 manufactures a ring roll product as follows. First, for example, the outer peripheral surface of the mandrel 11 is disposed in contact with the inner peripheral surface of the annular workpiece W, and the outer peripheral surface of the forming roll 12 is disposed in contact with the outer peripheral surface of the annular workpiece W. . Next, while rotating these, the mandrel 11 and the forming roll 12 are moved so as to be relatively close to each other. Thereby, while the thickness of the annular work W becomes thin, the diameter of the annular work W is expanded correspondingly, and a ring roll product is obtained. If the outer ring member 11B of the mandrel 11 is worn as the production of the ring roll product is repeated, the surface is scraped and repaired as described above.

  Thus, according to this embodiment, since the outer ring member 11B made of die steel or heat-resistant steel is disposed on the outer periphery of the core member 11A for the mandrel 11, the annular workpiece W abuts. The portion is made harder by the outer ring member 11B, and the core member 11A can be formed of a material cheaper than die steel or heat-resistant steel. Therefore, it can be made cheap as a whole. Moreover, since the thickness of the outer ring member 11B is thin as compared with the case where the whole is formed of die steel or heat-resistant steel, the inner ring is easily baked by the mass effect and can be hardened to the inside. Therefore, formation of a surface treatment film or the like can be omitted, and wear resistance can be improved at a low cost. Furthermore, since the inside of the outer ring member 11B can be hardened, if the surface is worn by use, it can be repaired by scraping the surface. Therefore, it can be used for a long time.

  The present invention has been described with reference to the embodiment. However, the present invention is not limited to the above embodiment, and various modifications can be made. For example, in the above embodiment, each component has been specifically described. However, not all the components may be provided, and other components may be provided.

  It can be used for the ring roll method.

  DESCRIPTION OF SYMBOLS 10 ... Ring roll molding machine, 11 ... Mandrel, 11A ... Core member, 11B ... Outer ring member, 11C ... Outer ring inclined part, 11D ... Middle core inclined part, 12 ... Forming roll, W ... Toroidal work

Claims (5)

A part of the annular workpiece is sandwiched between the forming rolls arranged on the inner circumferential side of the annular workpiece and arranged on the outer circumferential side of the annular workpiece, so that the annular workpiece is thinned and expanded. A mandrel that diameters,
A core member;
A mandrel comprising: an outer ring member made of die steel or heat-resistant steel disposed in a region where the annular workpiece abuts on an outer periphery of the core member.   2. The mandrel according to claim 1, wherein a thickness of a minimum thickness at a portion of the outer ring member in contact with the annular workpiece is 5 mm or more and 10 mm or less.   The mandrel according to claim 1, wherein the core member is made of a chromium molybdenum steel material, a nickel chromium molybdenum steel material, or a general structural rolled steel material. By sandwiching a part of the annular workpiece between a mandrel arranged on the inner circumferential side of the annular workpiece and a forming roll arranged on the outer circumferential side of the annular workpiece, the annular workpiece is A ring roll forming machine that expands the diameter while thinning,
The said mandrel has the structure of any one of Claims 1-3, The ring rule molding machine characterized by the above-mentioned.   A method for producing a ring roll product, wherein the ring roll product is produced by expanding the diameter while reducing the thickness of the annular workpiece using the ring roll molding machine according to claim 4.

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