WO2015053137A1 - Rouleau composite en alliage extra-dur et son procédé de production - Google Patents

Rouleau composite en alliage extra-dur et son procédé de production Download PDF

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Publication number
WO2015053137A1
WO2015053137A1 PCT/JP2014/076214 JP2014076214W WO2015053137A1 WO 2015053137 A1 WO2015053137 A1 WO 2015053137A1 JP 2014076214 W JP2014076214 W JP 2014076214W WO 2015053137 A1 WO2015053137 A1 WO 2015053137A1
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Prior art keywords
cemented carbide
outer layer
composite roll
inner layer
layer
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PCT/JP2014/076214
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English (en)
Japanese (ja)
Inventor
大島　昌彦
拓己 大畑
俊二 松本
裕允 小湊
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日立金属株式会社
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Priority to JP2015541534A priority Critical patent/JP6421758B2/ja
Publication of WO2015053137A1 publication Critical patent/WO2015053137A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B27/00—Rolls, roll alloys or roll fabrication; Lubricating, cooling or heating rolls while in use
    • B21B27/02—Shape or construction of rolls
    • B21B27/03—Sleeved rolls
    • B21B27/032—Rolls for sheets or strips
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F7/00—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression
    • B22F7/06—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite workpieces or articles from parts, e.g. to form tipped tools
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C29/00—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides
    • C22C29/02—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides based on carbides or carbonitrides
    • C22C29/06—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides based on carbides or carbonitrides based on carbides, but not containing other metal compounds
    • C22C29/08—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides based on carbides or carbonitrides based on carbides, but not containing other metal compounds based on tungsten carbide
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten

Definitions

  • the present invention comprises an outer layer excellent in wear resistance, rough skin resistance, etc. and an inner layer excellent in toughness, and is a highly durable cemented carbide composite roll suitable for rolling steel materials such as plate materials, wire materials, bar materials, And a manufacturing method thereof.
  • tungsten carbide (WC) cemented carbide with excellent wear resistance, rough skin resistance, etc., to meet the demands for higher quality of rolled materials, such as improved dimensional accuracy, and improved productivity by reducing the number of roll change man-hours.
  • Rolls for rolling are used, and cemented carbide rolling rolls having various structures have been proposed.
  • Japanese Patent Laid-Open No. 3-281007 discloses a roll body 105 having a fastening flange portion 103 fixed at both ends and a detachable fastening flange portion 104, and a thermal expansion coefficient of 15 ⁇ .
  • a cemented carbide rolling roll having a body 110 is proposed.
  • the tightening force of the tightening flange portions 103 and 104 is improved by utilizing the thermal expansion of the ring spacers 111 and 111.
  • the adhesion between the cemented carbide cylinder 110 and the roll body 105 is not sufficient with the tightening force by the tightening flange portions 103 and 104.
  • the cemented carbide cylindrical body 110 may slip with respect to the roll body 105 during rolling.
  • JP 2001-47111 A discloses a cemented carbide composite roll in which an outer layer member made of a WC-based cemented carbide is metal-bonded to the outer periphery of an inner layer member made of a material having excellent toughness.
  • a cemented carbide composite roll is proposed in which a WC-based cemented carbide intermediate layer having a lower content than the outer layer is provided, and the inner layer member and the intermediate layer are joined via a metal layer.
  • the WC has a gradient concentration from the outer layer member to the inner layer member and the physical properties such as the coefficient of thermal expansion and the elastic coefficient are continuously applied from the outer layer member to the inner layer member. It is described that the strength of the boundary joint is improved.
  • JP 2004-167501 is a cemented carbide composite roll in which a cemented carbide outer layer member is joined to the outer periphery of a steel or iron alloy inner layer member, and has a Young's modulus between the inner layer member and the outer layer member.
  • a composite roll for rolling made of cemented carbide characterized by providing an intermediate layer of 190 GPa or less is proposed.
  • Japanese Patent Laid-Open No. 2004-167501 absorbs strain between the outer layer and the inner layer by setting the Young's modulus of the intermediate layer to 190 GPa or less, and even if the thermal expansion coefficient difference between the outer layer and the inner layer is large, it is excessive in the roll.
  • Japanese Patent Application Laid-Open No. 2004-167501 exemplifies Invar alloy and SUS304 as the material of the intermediate layer.
  • JP 2003-275809 has proposed a composite roll for rolling in which a WC cemented carbide outer layer is directly metal-bonded to the outer periphery of an iron alloy inner layer containing 0.5 mass% or more of C.
  • Japanese Unexamined Patent Publication No. 2003-275809 describes that the obtained cemented carbide composite roll does not have a fragile ⁇ phase at the boundary joining portion and has high joining reliability.
  • cemented carbide composite rolls described in JP-A-2001-47111, JP-A-2004-167501, and JP-A-2003-275809 in which a cemented carbide outer layer having excellent wear resistance and an iron-based alloy inner layer are joined. It has been found that there is a possibility that the bonding reliability between the outer layer and the inner layer may not be sufficient to increase the size of the roll as in a hot sheet rolling roll having an outer diameter of 300 mm or more and a roll length of 500 mm or more. Further, when used in more severe rolling conditions, higher bonding strength between the outer layer and the inner layer is required.
  • an object of the present invention is a cemented carbide composite roll comprising a cemented carbide outer layer excellent in wear resistance, rough skin resistance, and the like and an iron-based alloy inner layer excellent in toughness, both of which have extremely high joint strength. And an efficient manufacturing method thereof.
  • the cemented carbide composite roll of the present invention is a cemented carbide outer layer and an iron-based alloy inner layer that are diffusion-bonded, and the inner layer body in the surface layer region of the inner layer adjacent to the bonding boundary with the outer layer. It has a C-enriched layer made of an iron-based alloy having a higher C concentration.
  • the thickness of the C concentrated layer is preferably 0.5 to 6 mm.
  • the C concentration at the junction boundary of the C concentrated layer is preferably 0.7 to 1.2% by mass. It is preferable that the C concentration in the C-concentrated layer gradually decreases from the joining boundary toward the inner layer main body.
  • the reduction rate of the C concentration in the depth direction in the C enriched layer is preferably 0.01% / mm or more.
  • the tensile strength at the boundary between the outer layer and the inner layer is preferably 600 MPa or more.
  • the cemented carbide outer layer preferably contains 70 to 88% by mass of WC particles.
  • the C concentration of the iron-based alloy inner layer body is preferably 0.2 to 0.5% by mass.
  • the iron-based alloy inner layer preferably contains 1.0% by mass or more in total of at least one selected from the group consisting of Cr, Ni, Mo, V, W, Ti and Nb.
  • the method of the present invention for producing a cemented carbide composite roll in which a cylindrical outer layer member made of a cemented carbide and an inner layer member made of an iron-based alloy are joined is obtained by carburizing the outer surface of the inner layer member.
  • the member and the inner layer member are diffusion bonded.
  • the thickness of the carburized layer formed by the carburizing process is preferably 0.5 to 10 mm.
  • the inner layer member is disposed inside the outer layer member, and a hollow cylindrical restraining member having a smaller coefficient of thermal expansion than the outer layer member is disposed outside the outer layer member in a temperature range from room temperature to a bonding temperature.
  • the outer layer member, the inner layer member, and the outer layer member so that the outer surface of the inner layer member that is most thermally expanded presses the inner surface of the outer layer member, and the inner surface of the restraining member that is not thermally expanded presses the outer surface of the outer layer member. It is preferable that a gap with the restraining member is set, and the inner surface of the outer layer member and the outer surface of the inner layer member are brought into close contact with each other by heating, so that the outer layer member and the inner layer member are diffusion bonded.
  • both end portions in the axial direction of the restraining member protrude from both end surfaces in the axial direction of the outer layer member.
  • the restraining member is thicker than the outer layer member.
  • the restraining member is preferably made of graphite or ceramics.
  • the restraining member is formed by coaxially stacking a plurality of ring members.
  • reaction preventing material is interposed between the restraining member and the outer layer member.
  • the cemented carbide outer layer and the iron-based alloy inner layer are joined via the C-concentrated layer, so the joining strength between the outer layer and the inner layer is high. Therefore, even a large rolling roll having an outer diameter of 300 mm or more and a roll length of 500 mm or more can be used for long-term rolling.
  • a large rolling roll having an outer diameter of 300 mm or more and a roll length of 500 mm or more can be used for long-term rolling.
  • the inner layer member made of an iron-based alloy and the outer layer made of a cemented carbide alloy that have been carburized in advance in the surface layer region are joined by the diffusion joining method or the HIP method, a joining boundary without a fragile ⁇ phase can be formed.
  • a cemented carbide composite roll in which an alloy outer layer and an iron-based alloy inner layer are firmly bonded can be obtained.
  • FIG. 4 (a) is an enlarged view of a portion A in the bag. It is sectional drawing which shows the diffusion bonding method using the constraining member comprised by the some ring member piled up coaxially. It is sectional drawing which shows the example which manufactures the cemented carbide composite roll of this invention by HIP method.
  • FIG. 2 is a cross-sectional view showing a joining experiment of Example 1.
  • FIG. It is a front view which shows a tension test piece.
  • 2 is a graph showing a C concentration distribution from the surface to the inside in the carburized layer of Example 1.
  • FIG. 4 is a graph showing the C concentration distribution from the joining boundary to the inside of the inner layer for joining test pieces 4 and 5 of Example 1.
  • FIG. 3 is a partial cross-sectional view showing a cemented carbide rolling roll disclosed in Japanese Patent Laid-Open No. 3-281007.
  • Cemented carbide composite roll 10 of the present invention that can be used for rolling a rolled material such as steel is composed of a cemented carbide outer layer 1 and a ferrous alloy as shown in FIG.
  • the inner layer 2 is made of an alloy, and a C concentrated layer 3 is provided at the boundary between the outer layer 1 and the inner layer 2.
  • the C-enriched layer is an iron-based alloy having a C concentration of 0.6% by mass or more and has a higher C concentration than the inner layer 2.
  • the outer layer 1 whose surface is in contact with the material to be rolled is required to have excellent wear resistance, rough skin resistance and mechanical strength, and the inner layer 2 constituting the roll shaft whose both ends are supported by bearings (not shown) is a high machine. Strength and toughness are required.
  • the cemented carbide outer layer 1 of the cemented carbide composite roll of the present invention is a sintered alloy in which hard WC particles are bonded with a metal such as Co, Ni, Cr, Fe, etc. Carbides such as Ta and Nb may be contained. Since the outer layer 1 has high wear resistance and mechanical strength, the average particle size of the WC particles is preferably 3 to 10 ⁇ m, the content of the WC particles is preferably 70 to 88% by mass, and more preferably 72 to 85% by mass. preferable. The thickness of the outer layer 1 is preferably set in the range of 5 to 50 mm in consideration of gradual wear due to rolling.
  • the iron-based alloy of the inner layer 2 is preferably steel.
  • inner layer 2 In order for inner layer 2 to have sufficient toughness, 0.2 to 0.5 mass% of C and 1.0 mass% or more in total of at least one selected from the group consisting of Cr, Ni, Mo, V, W, Ti and Nb Steel is preferred.
  • C is less than 0.2% by mass, the inner layer 2 does not have sufficient strength.
  • C exceeds 0.5% by mass, the toughness of the inner layer 2 is insufficient.
  • the content of other elements may be within the general composition range of steel materials.
  • the inner layer 2 Since the inner layer 2 has a larger thermal expansion coefficient than the outer layer 1 made of a cemented carbide having a small thermal expansion coefficient, it needs a transformation expansion characteristic to relieve strain generated by the thermal expansion. If this transformation is a pearlite transformation, due to plastic deformation at a high temperature, a large strain is generated due to a difference in thermal expansion coefficient in the process of cooling to room temperature, which causes roll breakage. For this reason, this transformation must be a bainite transformation or a martensitic transformation that occurs at low temperatures. For this reason, it is preferable that the inner layer contains 1.0% by mass or more in total of at least one selected from the group consisting of Cr, Ni, Mo, V, W, Ti, and Nb. In particular, the Cr content is preferably 0.5 to 1.5 mass%, the Mo content is preferably 0.1 to 0.5 mass%, and the Ni content is preferably 1.5 to 2.5 mass%.
  • a C concentrated layer 3 having a C concentration of 0.6% by mass or more was formed near the surface of the inner layer 1 to be joined with the outer layer 1 made of cemented carbide. It has been found that if formed, the diffusion of C from the cemented carbide outer layer 1 to the inner layer 2 can be substantially suppressed, thereby preventing the generation of ⁇ phase. Furthermore, since the C enriched layer 3 may be formed very close to the inner layer 2, the toughness of the iron-based alloy inner layer 2 is not impaired.
  • the outer diameter of the outer layer 1 is 300 mm or more and the roll length is 500 mm or more. It is possible to obtain a cemented carbide composite roll 10 having an excellent bonding strength.
  • FIG. 2 shows the C concentration distribution in the region including the C concentrated layer of the cemented carbide composite roll 10 of the present invention.
  • the horizontal axis represents the distance from the boundary with the outer layer 1 (the origin is the junction boundary with the outer layer 1), and the vertical axis represents the C concentration.
  • a layer having a C concentration of 0.6% by mass or more from the boundary with the outer layer 1 toward the inner layer 2 is referred to as a C concentrated layer 3.
  • the thickness of the C concentrated layer 3 is preferably 0.5 to 10 mm.
  • the thickness of the C concentrated layer 3 is less than 0.5 mm, C diffuses to the inner layer 2 side when bonded to the outer layer 1 and the C concentration of the C concentrated layer 3 becomes too low, and the cemented carbide of the outer layer 1 Since the ⁇ phase may occur in the inside, it is not preferable.
  • the thickness of the C enriched layer 3 exceeds 10 mm, the time for carburizing treatment for forming the C enriched layer 3 becomes longer, which is not preferable because the manufacturing cost increases.
  • the C concentration in the adjacent region of the outer layer is 0.7 to 1.2. It is preferable that it is mass%. If the C concentration in the adjacent region of the outer layer is 0.7% by mass or more, there is almost no diffusion of C from the outer layer 1 made of cemented carbide to the inner layer 2, and the generation of ⁇ phase in the outer layer 1 made of cemented carbide can be reliably prevented. , The strength reduction can be prevented. On the other hand, if the C concentration in the adjacent region of the outer layer exceeds 1.2% by mass, graphite is generated at the joining boundary, and the strength is lowered, which is not preferable.
  • the C concentration gradually decreases from the boundary with the outer layer 1 toward the inner layer 2.
  • the physical properties such as Young's modulus, thermal expansion coefficient, and hardness continuously change from the joining boundary toward the inner layer 2, the joining reliability increases.
  • the tensile strength at the boundary between the outer layer 1 and the inner layer 2 is preferably 600 MPa or more, more preferably 700 MPa or more so that the outer layer 1 and the inner layer 2 do not peel even when used for a long time in rolling.
  • the tensile strength at the boundary between the outer layer 1 and the inner layer 2 can be measured by a tensile test of a test piece including the boundary between the outer layer 1 and the inner layer 2.
  • FIG. 3 shows a manufacturing process of the cemented carbide composite roll 10 of the present invention.
  • carburizing treatment is performed on the outer peripheral surface of a columnar or cylindrical inner layer member 12 made of an iron-based alloy.
  • a solid carburizing method, a liquid carburizing method, or a gas carburizing method can be used for the carburizing treatment, but a gas carburizing method is preferable in order to form a uniform carburized layer.
  • the carburized layer 13 becomes the C concentrated layer 3 after being joined to the outer layer 1, and the C concentration is preferably 0.7 to 1.2% by mass on the outermost surface (outer layer adjacent region).
  • the C concentration on the surface of the carburized layer 13 is less than 0.7 mass%, the bonding strength with the outer layer 1 is insufficient, and the C concentrated layer 3 may not be formed.
  • the C concentration on the surface of the carburized layer 13 exceeds 1.2% by mass, graphite may be generated at the bonding boundary with the outer layer, resulting in a decrease in bonding strength.
  • the C concentration gradually decreases from the surface toward the inside of the inner layer 2.
  • the thickness of the carburized layer 13 is preferably 0.5 to 10 mm.
  • the thickness of the carburized layer 13 is less than 0.5 mm, not only the bonding strength with the outer layer is insufficient, but also the C concentrated layer 3 may not be formed at the bonding boundary. On the other hand, it takes an excessive amount of time to form the carburized layer 13 having a thickness of more than 10 mm, which increases the manufacturing cost.
  • a preferable thickness of the carburized layer 13 is 2 to 5 mm.
  • the outer layer member 11 made of cemented carbide is joined to the inner layer member 12 on which the carburized layer 13 is formed.
  • the joining method is not limited as long as the inner layer member 12 and the outer layer member 11 are joined without a gap, but a diffusion joining method and a hot isostatic pressure (HIP) method are preferably used.
  • FIG. 4 shows a method for producing the cemented carbide composite roll of the present invention by the diffusion bonding method.
  • an inner layer member (corresponding to a roll shaft) 12 whose surface is carburized is placed on a base 8.
  • the cylindrical outer layer member 11 is placed on the cylindrical cradle 9.
  • the cradle 9 is preferably made of a material that is inactive with respect to the outer layer member 11, similarly to the restraining member described later.
  • the cradle 9 is preferably made of graphite or ceramics.
  • the cylindrical restraining member 16 having a smaller coefficient of thermal expansion than the outer layer member 11 is placed on the base 8 so as to surround the outer layer member 11.
  • the inner layer member 12, the outer layer member 11, and the restraining member 16 arranged in this way are heated in an inert atmosphere to perform diffusion bonding between the outer layer member 11 and the inner layer member 12.
  • the diffusion bonding temperature is preferably 1000 to 1280 ° C. If the diffusion bonding temperature is less than 1000 ° C, sufficient bonding strength may not be obtained. If the diffusion bonding temperature exceeds 1280 ° C, a ⁇ phase is generated in the cemented carbide near the bonding interface, and the bonding strength is reduced. descend.
  • the diffusion bonding temperature is more preferably 1100 to 1280 ° C, and most preferably 1200 to 1260 ° C.
  • the time for maintaining the diffusion bonding temperature may be about 1 to 120 minutes, preferably 30 to 90 minutes.
  • an inert gas such as N 2 or Ar, a reducing gas such as H 2 , or a vacuum can be used.
  • the thermal expansion coefficients of the inner layer member 12, the outer layer member 11, and the restraining member 16 must satisfy the relationship of inner layer member 12> outer layer member 11> restraining member 16. Don't be.
  • the thermal expansion coefficient of the iron alloy inner layer member 12 in the range from room temperature to 1000 to 1280 ° C. is about 11 to 15 ⁇ 10 ⁇ 6 / ° C.
  • the thermal expansion coefficient of the cemented carbide outer layer member 11 is 6 About 10 ⁇ 10 -6 / ° C. Therefore, the thermal expansion coefficient of the restraining member 16 must be sufficiently smaller than these in the temperature range from room temperature to the diffusion bonding temperature.
  • the restraining member 16 is preferably made of graphite or ceramics having a thermal expansion coefficient of about 4 to 9 ⁇ 10 ⁇ 6 / ° C. Further, the restraining member 16 must sufficiently withstand the diffusion bonding temperature and the diffusion bonding stress, and therefore must have high strength and high rigidity at the diffusion bonding temperature. Furthermore, the restraining member 16 is preferably made of a material that is not bonded to the cemented carbide at the diffusion bonding temperature. Graphite or ceramics also satisfy these conditions. Among them, isotropic graphite having a thermal expansion coefficient of 6 ⁇ 10 ⁇ 6 / ° C. or less and a bending strength at 1000 ° C. of 30 MPa or more is particularly preferable.
  • the outer surface of the inner layer member 12 that is most thermally expanded by heating sufficiently presses the inner surface of the outer layer member 11, and the inner surface of the restraining member 16 that is least thermally expanded is the outer layer member 11. It is necessary to set a gap G 1 between the inner layer member 12 and the outer layer member 11 and a gap G 2 between the outer layer member 11 and the restraining member 16 so as to sufficiently press the outer surface of the member [see FIG. 4 (b)]. .
  • the diameter of the steel inner layer member 12 (thermal expansion coefficient: 13 ⁇ 10 ⁇ 6 / ° C.) is 275 mm and the outer layer member 11 made of cemented carbide (thermal expansion coefficient: 8 ⁇ 10 ⁇ 6 / ° C.)
  • the gap G 1 between the outer layer member 11 and the inner layer member 12 is preferably 0.3 to 1.5 mm
  • the gap G 2 between the outer layer member 11 and the restraining member 16 is 1 to 2 mm.
  • the restraint member 16 having a smaller coefficient of thermal expansion than the outer layer member 11 is disposed outside the outer layer member 11, and the thermal expansion of the outer layer member 11 and the inner layer member 12 is restrained by the restraint member 16, so that the inner layer that is most thermally expanded.
  • the outer surface of the member 12 is in close contact with the inner surface of the outer layer member 11 with a surface pressure (bonding surface pressure) necessary for diffusion bonding. This makes it possible to obtain a cemented carbide composite roll with good bonding reliability even when the outer diameter is 300 mm or more and the roll length is 500 mm or more.
  • the outer layer member 11 of the restraining member 16 long the preferably than the total length L 1 of the total length L 3 is the outer layer member 11 of the restraining member 16, also the axial end faces 6a of the restraining member 16, 6b are axial outer member 11 It is preferable that the length D projects from both end faces 1a and 1b. Accordingly, since the outer member 11 can be uniformly constrained between axially opposite ends, uniformly diffusion bonding to the inner layer member 12 over the entire length L 1 of the outer member 11. For example, when the total length L 2 of the inner layer member 12 is 800 mm and the total length L 1 of the outer layer member 11 is 700 mm, D is preferably 10 to 100 mm.
  • the restraining member 16 Since the restraining member 16 must sufficiently restrain the outer layer member 11 without being deformed or damaged at the diffusion bonding temperature, it is preferable that the restraining member 16 is sufficiently thicker than the outer layer member 11 in the radial direction.
  • the thickness T 3 of the restraining member 16 is preferably 100 to 150 mm.
  • the constraining member 16 can be configured by stacking a plurality (six in the illustrated example) of relatively short ring members 61 to 66 coaxially in the axial direction. Since the thermal expansion restraining force of the restraining member 16 acts in the radial direction, even if the ring members 61 to 66 separated in the axial direction are used, the thermal expansion restraining effect is the same.
  • each of the ring members 61 to 66 is preferably made of graphite or ceramics.
  • reaction preventing material between the restraining member 16 and the outer layer member 11 so that the reaction does not occur even when contacting the outer layer member 11 at the diffusion bonding temperature.
  • the reaction preventing material ceramics such as alumina having low reactivity with the outer layer member 11 is preferable.
  • the reaction inhibitor may be in the form of powder or woven fabric. In the case of powder, the slurry may be applied to the outer surface of the outer layer member 11 or the inner surface of the restraining member 16. In the case of a woven fabric shape, the outer layer member 11 may be wound around the outer periphery.
  • the outer layer member 11 and the inner layer member 12 are diffusion bonded, the outer layer member 11 becomes the outer layer 1 and the inner layer member 12 becomes the inner layer 2. Further, the carburized layer 13 of the inner layer member 12 becomes the C concentrated layer 3. Thereafter, the restraining member 16 is removed to obtain a cemented carbide composite roll 10 in which the outer layer 1 and the inner layer 2 are integrated. If necessary, a desired portion of the cemented carbide composite roll 10 is machined to obtain a dimension and shape suitable for hot sheet rolling.
  • Hot isostatic pressure (HIP) method As shown in FIG. 6, an iron-based alloy obtained by putting a cylindrical outer layer member 11 into a cylindrical HIP can body 20 a and then carburizing inside the cylindrical outer layer member 11.
  • the inner layer member 12 is disposed, the donut plates 20b, 20b covering the end surface of the outer layer member 11 are welded to the cylindrical HIP can body 20a, and the cup portions 20c, 20c covering the inner layer member 12 are further attached to the donut plates 20b, 20b. Weld and depressurize the resulting HIP can. Then, the HIP can is put into the HIP device and the HIP process is performed.
  • the HIP temperature is preferably 1100 to 1300 ° C.
  • the HIP pressure is preferably 100 to 140 MPa.
  • the outer layer member 11 and the inner layer member 12 are firmly joined by HIP, the outer layer member 11 becomes the outer layer 1, and the inner layer member 12 becomes the inner layer 2. Further, the carburized layer 13 of the inner layer member 12 becomes the C concentrated layer 3.
  • the HIP can 20 is removed by machining to obtain a cemented carbide composite roll 10 in which the outer layer 1 and the inner layer 2 are integrated. Also in this case, a desired portion of the cemented carbide composite roll 10 may be machined as necessary.
  • the gap between the outer layer member 11 and the inner layer member 12 may be filled with a powder having a high C concentration. Examples of such high C concentration powder include WC 50 -Co 50 cemented carbide.
  • Example 1 Using a cemented carbide having the composition shown in Table 1, a cylindrical outer layer test piece 31 having an outer diameter of 20 mm and a thickness of 20 mm shown in FIG. 7 was produced. Further, a disk-shaped inner layer test piece 32 having an outer diameter of 30 mm and a thickness of 10 mm shown in FIG. 7 was prepared using an iron-based alloy having the composition shown in Table 2. The inner layer test piece 32 was subjected to gas carburizing treatment to form a carburized layer 13 having a target depth of 4 mm and a target C concentration of 0.75 to 0.9% by mass on the surface. FIG. 9 shows the C concentration distribution from the surface to the inside of the carburized layer 13.
  • the C concentration was measured by cutting out a small sample from the test piece 32 and using a carbon analyzer. As a result of the measurement, the thickness of the carburized layer was about 4 mm, and the maximum value of C concentration (concentration on the surface) was 0.92% by mass. The surface layer portion of the carburized layer 13 was removed by machining to a depth of 0.2 mm.
  • the average particle size of the WC particles was 5 ⁇ m.
  • the outer layer test piece 31 and the inner layer test piece 32 are stacked as shown in FIG. 7, and after being placed in a graphite jig 34, they are pressurized from above in a vacuum, diffusion bonded under the conditions shown in Table 3, and bonded test pieces 1 ⁇ 5 was obtained. Each bonding test piece 1 to 5 was cut and the bonding interface was observed. For the bonding specimens 4 and 5, the C concentration distribution from the bonding boundary to the inner layer was examined. The results are shown in FIG. In Table 3, the C-concentrated layer means that the C concentration is in the range of 0.6% by mass or more.
  • the ⁇ phase at the bonding interface between the inner layer test piece 32 and the outer layer test piece 31 was not observed in the bonding test pieces 1 to 4, but was confirmed in the bonding test piece 5.
  • Example 2 An outer layer test piece 31 ′ having a composition shown in Table 1 having a diameter of 25 mm ⁇ a length of 75 mm and an inner layer test piece 32 ′ made of an iron-based alloy having a composition shown in Table 2 having a diameter of 25 mm ⁇ a length of 75 mm (implemented) A carburized layer 13 was formed under the same conditions as in Example 1.). After placing the outer layer test piece 31 ′ and the inner layer test piece 32 ′ in the graphite jig 34 as shown in FIG. 7, the jig 34 is pressed from above in vacuum, and diffusion bonding is performed under the conditions shown in Table 4. The test specimens 1 ′ to 5 ′ were prepared.
  • a tensile test piece 40 having a shape shown in FIG. 8 (consisting of an outer layer test piece part 41 and an inner layer test piece part 42 having a boundary in the center between the gauge points) was prepared from each of the joining test pieces 1 ′ to 5 ′. .
  • the outer layer test piece portion 41 was formed from the outer layer test piece 31 ', and the inner layer test piece portion 42 was formed from the inner layer test piece 32'.
  • the diameter of the tensile test piece 40 was 6.3 mm, and the gauge distance was 19 mm.
  • the tensile strength at the joining boundary was measured by a tensile test.
  • the results are shown in Table 4.
  • the tensile strength at the boundary between the outer layer test piece portion 41 and the inner layer test piece portion 42 was 600 MPa or more for the tensile test pieces 1 to 4, but 530 MPa for the tensile test piece 5 It was low. This is considered to be because the ⁇ phase was formed at the bonding interface in the bonding test piece 5 '.
  • Example 3 Using a ferrous alloy having the composition shown in Table 2, a roll shaft-shaped inner layer member 12 having an outer diameter of 276 mm and a total length of 1930 mm was produced. A carburized layer 13 having a target thickness of 4 mm and a target C concentration of 0.75 to 0.9% by mass was formed on the surface of the inner layer member 12 by a gas carburizing method. A test piece was collected from the end of the inner layer member 12, and the C concentration was measured in the depth direction of the carburized layer 13. As a result, it was found that the C concentration distribution was the same as in FIG. Thereafter, the carburized layer 13 was removed by machining by a depth of 0.5 mm.
  • a hollow cylindrical outer layer member 11 having an outer diameter of 364 mm, an inner diameter of 276 mm, and a total length of 680 mm was manufactured using a cemented carbide having the composition shown in Table 1. Further, a graphite hollow cylindrical restraining member 16 having an outer diameter of 600 mm, an inner diameter of 365.5 mm, and a total length of 800 mm was produced.
  • the end portions of the outer layer 1 and the inner layer 2 in the cemented carbide composite roll 10 were visually inspected, and the entire bonding surface was inspected. As a result, no boundary defect was observed over the entire bonding surface. Further, no peeling between the outer layer 1 and the inner layer 2 was observed.
  • Outer layer 2 Inner layer 3: C thickened layer 8: Base 9: cradle 10: Cemented carbide composite roll 11: Outer layer member 12: Inner layer member 13: Carburized layer 16: Restraint member 20: HIP can 31: Outer layer specimen 32: Inner layer specimen 34: Graphite jig 61-66: Ring member for restraint member L 1 : Length of outer layer member L 2 : Length of inner layer member L 3 : Length of restraint member D: Length of the restraining member extending from each end of the outer layer member T 1 : Thickness of outer layer member T 2 : Diameter of inner layer member T 3 : Thickness of restraining member G 1 : Gap between the outer layer member and the inner layer member G 2 : Gap between the outer layer member and the restraining member

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Abstract

La présente invention concerne un rouleau composite en alliage extra-dur ayant : une couche externe d'alliage extra-dur et une couche interne d'alliage à base de fer fixée par diffusion dans celle-ci ; une couche concentrée de carbone comprenant un alliage à base de fer ayant une concentration de carbone plus élevée qu'un corps principal de couche interne, dans une zone de surface de la couche interne adjacente à la limite de fixation avec la couche externe ; une concentration de carbone de 0,7 % à 1,2 % en masse dans ladite limite de fixation de la couche concentrée de carbone ; et une épaisseur de 0,5 à 6 mm.
PCT/JP2014/076214 2013-10-09 2014-09-30 Rouleau composite en alliage extra-dur et son procédé de production WO2015053137A1 (fr)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5838683A (ja) * 1982-07-05 1983-03-07 Sumitomo Electric Ind Ltd 複合耐摩部材の製造法
JPH105825A (ja) * 1996-06-19 1998-01-13 Hitachi Metals Ltd 超硬合金製複合ロール
JP2002224715A (ja) * 2001-02-05 2002-08-13 Kawasaki Steel Corp 厚鋼板の圧延方法
JP2003275809A (ja) * 2002-03-18 2003-09-30 Hitachi Metals Ltd 圧延用複合ロール

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006181628A (ja) * 2004-12-28 2006-07-13 Jfe Steel Kk 厚鋼板の圧延方法および厚鋼板の製造方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5838683A (ja) * 1982-07-05 1983-03-07 Sumitomo Electric Ind Ltd 複合耐摩部材の製造法
JPH105825A (ja) * 1996-06-19 1998-01-13 Hitachi Metals Ltd 超硬合金製複合ロール
JP2002224715A (ja) * 2001-02-05 2002-08-13 Kawasaki Steel Corp 厚鋼板の圧延方法
JP2003275809A (ja) * 2002-03-18 2003-09-30 Hitachi Metals Ltd 圧延用複合ロール

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