WO2017201729A1 - 复合铸造异型轧辊及其制备方法 - Google Patents

复合铸造异型轧辊及其制备方法 Download PDF

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Publication number
WO2017201729A1
WO2017201729A1 PCT/CN2016/083643 CN2016083643W WO2017201729A1 WO 2017201729 A1 WO2017201729 A1 WO 2017201729A1 CN 2016083643 W CN2016083643 W CN 2016083643W WO 2017201729 A1 WO2017201729 A1 WO 2017201729A1
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casting
roll
cast
shape
blank
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PCT/CN2016/083643
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English (en)
French (fr)
Inventor
袁厚之
张凝
刘行一
王平
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山东省四方技术开发有限公司
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Priority to PCT/CN2016/083643 priority Critical patent/WO2017201729A1/zh
Priority to CN201680003083.7A priority patent/CN107073570B/zh
Priority to US15/723,742 priority patent/US10814382B2/en
Publication of WO2017201729A1 publication Critical patent/WO2017201729A1/zh

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D19/00—Casting in, on, or around objects which form part of the product
    • B22D19/16—Casting in, on, or around objects which form part of the product for making compound objects cast of two or more different metals, e.g. for making rolls for rolling mills
    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/22—Moulds for peculiarly-shaped castings
    • B22C9/24—Moulds for peculiarly-shaped castings for hollow articles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D25/00—Special casting characterised by the nature of the product
    • B22D25/02—Special casting characterised by the nature of the product by its peculiarity of shape; of works of art
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/18—Hardening; Quenching with or without subsequent tempering
    • C21D1/19—Hardening; Quenching with or without subsequent tempering by interrupted quenching
    • C21D1/20—Isothermal quenching, e.g. bainitic hardening
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/38—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for roll bodies
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C37/00—Cast-iron alloys
    • C22C37/04—Cast-iron alloys containing spheroidal graphite
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C37/00—Cast-iron alloys
    • C22C37/06—Cast-iron alloys containing chromium
    • C22C37/08—Cast-iron alloys containing chromium with nickel
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C37/00—Cast-iron alloys
    • C22C37/10—Cast-iron alloys containing aluminium or 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
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • 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
    • C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
    • 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
    • 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
    • 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
    • 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/56—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.7% by weight of carbon
    • 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
    • B21B27/035—Rolls for bars, rods, rounds, tubes, wire or the like
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/004—Heat treatment of ferrous alloys containing Cr and Ni

Definitions

  • the invention relates to a roll casting technology, in particular to a preparation method for a profiled roll by using a composite structure casting method.
  • the preparation method adopts a two-liquid double external casting method to prepare a profiled roll for the production of a steel pipe and a cold-formed steel.
  • the sizing rolls are the sizing rolls
  • the tension reducing machines are the rolls
  • the steel tubes and the round steel inclined roll straightening rolls are the straightening rolls.
  • most of the rolls in the welded steel pipe unit and some of the rolls in the cold-formed steel unit are curved surface-shaped rolls with large diameters at both ends and small intermediate diameters.
  • the structure of this type of profiled roller belongs to the roller and shaft separation type, that is, it has a middle hole, and is mounted on the frame after the shaft is installed in the middle hole.
  • profiled rolls are the most consumed workpieces in the production of seamless steel pipes, welded steel pipes and cold-formed steels. They are subjected to rolling and sliding friction under large compressive stress, and are subjected to repeated impacts on the head and tail of the rolled material. It is subjected to the chilling heat of high temperature rolled materials and cooling water, and the working environment is very bad.
  • profiled rolls can be divided into two categories according to the use temperature: one type is used at low temperature, such as straightening rolls, welded steel pipes and cold-formed steel rolls, etc., and is basically used at normal temperature. Only when the heat treatment line is straightened, the straightening rolls are subjected to the temperature of 400 ° C ⁇ 500 ° C, and the welded extrusion rolls of welded steel tubes and cold-formed steels are also subjected to the high temperature generated during the welding of the rolled materials. At the same time, both of them are subject to the chilling effect of the cooling water.
  • the other type is used at high temperatures, such as sizing rolls and reduction rolls, and the temperature of the rolled material is generally 800 ° C to 1100 ° C.
  • the above-mentioned profiled rolls have to be repaired by multiple vehicles and grinding in use. Therefore, the profiled roll is required to have a sufficiently thick working layer of abrasion resistance, impact resistance, and chilling heat resistance, and should be combined with a core of high strength and high toughness.
  • the profiled roll in this ideal state should be a bimetallic composite structure that satisfies two different requirements.
  • the above-mentioned rolls are all made of single metal, and it is difficult to balance the requirements of two different performances for one type of roll.
  • the above-mentioned straightening rolls, welded steel pipes and cold-formed steel rolls also have a wide variety of specifications, and the same specifications and varieties are small in number, and most of the drawings are only one to two pieces.
  • the finished product roll can reach a maximum of ten pieces per piece. A few tons, the small single weight is less than 1 kg each.
  • forged rolls of D2 (X155CrVMo12-1, SKD11) cold work die steel and forged H13 (X40CrMoV5-1, SKD61) hot work die steel are generally used.
  • the forging process is free forging into a cylinder, and the hole type and the inner hole are obtained by machining, and the material utilization rate is as low as 50% or less.
  • the forging and heat treatment are difficult, the process requirements are strict, the bimetal structure cannot be realized, and the material and energy consumption are large, and the production cost is high.
  • the above-mentioned sizing roller and tension reducing roller are usually made of high alloy ductile iron (generally Ni3Mo1), and alloy elements such as Ni, Mo, Cr, etc. are added to the ductile iron to improve the wear resistance of the ductile iron roll. .
  • alloy elements such as Ni, Mo, Cr, etc.
  • Cr and Mo anti-spheroidizing elements
  • the sizing roller and the tension reducing roller belong to the thick spheroidal graphite iron with uneven wall thickness, the austempering is difficult, so the normalizing process is conventionally used, and the obtained bainite structure is dependent on the alloys of Ni, Cr, Mo and the like having a relatively high content. The element is obtained.
  • the strength and toughness of the same workpiece with normalizing are much lower than that of the isothermal quenching part. It is easy to crack and break when the remaining wall thickness is thin after multiple processing.
  • the centrifugal casting has the following limitations: if a metal mold is required. When manufacturing a single sizing roller and a sizing roller that are smaller in weight, it is necessary to make a plurality of sets of dies, and multiple centrifuges are required to work at the same time, which greatly increases the production cost. Since the wall thickness of the sizing roller and the sizing roller is large, that is, the difference between the outer diameter of the roller and the diameter of the inner hole is large, centrifugal casting is difficult.
  • the curved surface having a large diameter at both ends and a small intermediate diameter cannot be realized by centrifugal casting, that is, the cast curved surface cannot be removed from the centrifugal metal mold. Therefore, only the cylinder can be centrifugally cast and processed. The processing and material consumption of the rolls is greatly increased.
  • the above-mentioned profiled roll adopts a full-profile blank and a conventional casting method, it is easy to solidify a portion having a small intermediate diameter, so that the lower portion is insufficiently filled to cause defects and cause waste.
  • the invention provides a composite casting profiled roll for the manufacture of profiled rolls used in steel pipes and cold-formed steel rolling mills, and a casting method for providing a simple and practical two-liquid double-shaped profiled roll capable of ensuring quality, and A method for preparing a profiled roll and a cast profiled roll.
  • the technical scheme of the composite casting profiled roll of the invention is as follows:
  • the roll body of the composite casting profiled roll of the present invention has a large diameter at both ends, a small intermediate diameter, and a roll body having a curved shape; the curved shape is composed of a composite combination of an inner layer and an outer layer, and a composite of an inner layer and an outer layer.
  • the bonding layer is gradually reduced from bottom to top to a curved shape inwardly, along the central axis of the roll It has a center hole for use when mounting the shaft.
  • the composite casting profiled roll of the invention adopts two composite materials, and adopts a two-liquid double-external casting method, and the steps are as follows:
  • Blank design According to the curved shape of the roller body with large diameter at both ends and small intermediate diameter, the outer curved surface and the upper and lower end faces of the blank are designed according to the outer curved surface and the upper and lower end faces of the finished product.
  • the middle hole is in accordance with the outer curved surface of the blank. Designed to taper from bottom to top to an inwardly curved inner surface.
  • the blank is designed as an inner layer and an outer layer.
  • the composite layer of the inner layer and the outer layer is gradually reduced from the bottom to the inner curved shape, and the cross-sectional area of the inner layer and the outer layer is from the bottom to the bottom.
  • the diameter of the inner and outer design boundary surface gradually decreases from the bottom to the top and is excessively smooth.
  • the mold design is two parts: casting inner shape and casting outer shape; the casting inner design is gradually from bottom to top. The inner surface and the lower end surface of the inner curved surface which are curved inward are reduced, and the cast outer shape is designed as a cast outer shape of the inner layer and a cast outer shape of the outer layer; the cast outer shape of the inner layer is a design boundary surface and upper The end face and the outer shape of the outer layer are the outer curved surface and the upper end surface of the blank.
  • Smelting Simultaneously smelting the inner and outer layers of the desired metal melt.
  • Casting firstly assemble the casting inner shape and the inner casting shape, and insert the inner casting shape from the top to the bottom to form the inner cavity of the blank and seal it, and the inner layer will be smelted.
  • the molten metal is poured into the inner cavity of the blank.
  • the casting appearance of the inner layer is removed when the solidification temperature of the metal is maintained at 850 ° C to 950 ° C, and the casting of the outer layer is quickly performed.
  • the outer shape forms the outer cavity of the blank and is sealed, and the molten metal of the outer layer is poured into the outer cavity of the blank.
  • the outer shape of the outer layer is removed, and the composite is completed.
  • the casting process of the cast profiled roll forms a composite bond layer of the two layers of the outer layer and the inner layer.
  • the composite casting profiled roll of the invention uses two kinds of composite materials to respectively cast different materials, one is a high chromium cast iron outer layer and a cast steel inner layer composite material, and the composition thereof is based on mass percentage: high chromium cast iron outer layer: C : 2.0% to 2.6%, Si: 0.2% to 0.5%, Mn: 0.6% to 1.0%, Cr: 11.0% to 18.0%, Ni: 0.5% to 1.5%, Mo: 0.5% to 1.5%, W: 0.5 % ⁇ 1.5%, Zr: 0.1% ⁇ 0.3%, Nb: 0.05% ⁇ 0.15%, Ti: 0.05% ⁇ 0.15%, RE: 0.05% ⁇ 0.15%, P: ⁇ 0.030%, S: ⁇ 0.025%, the rest It is Fe and inevitable impurities.
  • the content of Mo+W+Zr is 1.2% or more and 2.2% or less by mass percentage, and Nb+Ti+RE The content is 0.10% or more and 0.40% or less by mass percentage;
  • the inner layer of the cast steel is cast carbon steel or low alloy cast steel.
  • the other is an alloy ductile iron outer layer and a ductile iron inner layer composite material, and the composition of the alloy ductile iron outer layer is expressed by mass percentage: C: 3.0% to 3.8%, Si: 1.4% to 1.8%, Mn: ⁇ 0.35 %, Ni: ⁇ 2.5%, Cu: 0.4% to 1.0%, Mo: 0.3% to 1.0%, Cr: 0.1% to 0.3%, B: ⁇ 0.08%, Mg: 0.04% to 0.10%, Bi: 0.0004% ⁇ 0.0005%, Sb: 0.0002% to 0.0003%, P: ⁇ 0.04%, S: ⁇ 0.02%, and the rest are Fe and unavoidable impurities.
  • the content of Ni+Cu is 0.4% or more and 2.5% or less by mass percentage
  • the content of Cr+B is 0.05% or more and 0.25% or less by mass percentage.
  • the composition of the inner layer of ductile iron is: C: 3.0% to 3.8%, Si: 2.2% to 2.7%, Mn: ⁇ 0.35%, Cu: 0.4% to 0.6%, Mg: 0.04% to 0.10%, P: ⁇ 0.04%, S: ⁇ 0.02%, and the balance is Fe and unavoidable impurities. Austempering heat treatment is performed when alloyed ductile iron is used.
  • the technical solution of the cast profiled roll of the present invention and the preparation method thereof is a profiled roll cast using a metal material.
  • the utility model is characterized in that the roller body of the profiled roll has a curved shape with a large diameter at both ends and a small intermediate diameter, and has a middle hole along the central axis of the roll.
  • the preparation method of the cast profiled roll is as follows:
  • Blank design According to the curved shape of the roller body with large diameter at both ends and small intermediate diameter, the outer curved surface and the upper and lower end faces of the blank are gradually reduced from the bottom to the upward curved surface according to the outer curved surface of the finished product, and the upper and lower end faces are added. Machining allowance; the middle hole is designed to be gradually reduced from the bottom to the inner curved surface in accordance with the outer curved surface of the blank.
  • the cross-sectional areas of the above two designs gradually increase or remain consistent from bottom to top.
  • the mold design According to the outer curved surface and the shape of the mesial surface of the roll blank design and the required machining allowance, the mold design is two parts: casting inner shape and casting outer shape; the casting inner design is gradually from bottom to top. The inner surface and the lower end surface of the inner curved surface which are curved inwardly are reduced, and the outer shape of the casting is designed to gradually reduce the outer curved surface of the blank from the bottom to the inner curved surface shape and the upper end surface which are curved inward;
  • Smelting a single metal melt required for smelting
  • the inner part of the casting is assembled with the outer shape of the casting, the casting shape is formed on the casting inner shape from the top to the bottom, and the blank cavity is formed and sealed, and the smelted single metal molten metal is poured into the blank cavity. After the solidification of the molten metal, the casting appearance is removed, and the casting process of the casting profiled roll is completed;
  • the invention can be applied to a welded steel tube rolling mill, a cold-formed steel rolling mill, a steel pipe straightening machine, and a hot rolling seamless Steel pipe sizing machine and reducer and other equipment.
  • the composite casting profiled roll prepared by the two-liquid double-external casting method of the invention and the cast profiled roll prepared by using the single-metal material of the invention obtain the roller body with wear resistance, impact resistance and chilling heat resistance.
  • the working layer is obtained, and a core of high strength and high toughness is obtained. It satisfies the requirements of the service conditions of the rolls used in welded steel pipes and cold-formed steel rolling mills, and at the same time makes the rolls have a long service life, reduces the manufacturing cost of the rolls, and improves the economic benefits of the production of welded steel pipes and cold-formed steels. .
  • FIG. 1 is a schematic structural view of a steel pipe straightening machine roll; a schematic view of a profiled roll having a large diameter at both ends, a small intermediate diameter, and a center hole;
  • Figure 2 is a schematic view showing the structure of a profiled roll of a steel pipe and a cold-formed steel mill roll having a large diameter at both ends, a small intermediate diameter, and a center hole;
  • Figure 3 is a schematic cross-sectional view of a roll blank design; in the figure, 3-1 is the inner layer, 3-2 is the outer layer, 3-3 is the actual required finished product indicated by the broken line, and 3-4 is the inner and outer boundary dividing surface;
  • Figure 4 is a schematic cross-sectional view showing the assembly of the cast inner mold and the inner cast cast shape in the roll mold; in the figure, 4-1 is the cast outer shape of the inner layer, 4-2 is the cast inner type, and 4-3 is The inner cavity, 4-4 is the sealing device, and 4-5 is the casting positioning device.
  • Figure 5 is a schematic cross-sectional view showing the assembly of the inner and outer layers of the roll mold; in the figure, 5-1 is the outer shape of the casting, 5-2 is the inner and outer boundary surface, and 5-3 is the outer The layer cavity, 5-4 is the sealing device, 5-5 is the mold positioning device, 3-1 is the cast inner layer, and 4-2 is the casting inner type.
  • 6 is a schematic cross-sectional view showing the assembly of a cast inner mold and a cast outer mold in a single metal roll mold; in the figure, 6-1 is a cast outer shape, 6-2 is a cast inner type, and 6-3 is a blank cavity, 6-4 is a sealing device, and 6-5 is a mold positioning device.
  • the profiled rolls according to the present invention are all curved-shaped rolls having a large diameter at both ends and a small intermediate diameter.
  • the structure of this type of profiled roller is a roller-shaft separation type, that is, it has a middle hole, and the shaft is mounted in the middle hole and then mounted on the frame. Because the profiled rolls need to be supported in steel pipe production equipment such as steel pipes and cold-formed steel The working environment is very harsh due to the friction and impact under the large compressive stress and the chilling heat of the high temperature rolled material and the cooling water. At the same time, it has to be repaired several times during the use of the car. Therefore, the rolls are required to have a sufficiently thick working layer to meet the special requirements of harsh conditions.
  • a casting method is designed which meets the quality requirements of curved surface shaped rolls having large diameters at both ends and small intermediate diameters.
  • Such profiled rolls also require a combination of a sufficiently thick working layer and a high strength, high toughness core.
  • the profiled rolls in the ideal state should be made of a bimetallic composite structure that satisfies two different requirements.
  • the present invention provides a simple and practical two-liquid double-external casting method for the preparation of the profiled roll composite structure.
  • a special-shaped roll casting method for ensuring quality is also provided for the casting of a profiled roll of a single metal material.
  • the casting molding method of the present invention is more similar to the finished product than the forging type method, and can add more alloying elements than the forging type method, thereby improving the technical performance of the rolls. Since the casting method can save a large amount of material and energy, and the service life of the steel pipe for production is improved, the casting molding method can more and more meet the demand of the steel pipe industry, thereby further promoting the technological progress of the foundry industry.
  • the roll body of the roll is a curved shape with a large diameter at both ends and a small intermediate diameter.
  • the curved shape is formed by combining the inner layer and the outer layer.
  • the composite bonding layer of the inner layer and the outer layer is gradually reduced from the bottom to the top to be curved inward; and has a center hole along the central axis of the roll for use in mounting the shaft.
  • the composite structure casting profiled roll of the present invention is realized by a two-liquid double-external casting method and step.
  • the outer curved surface and the upper and lower end faces of the roll are added with machining allowance according to the outer curved surface and the upper and lower end faces of the finished product of the profiled roll.
  • the middle hole is designed as an inner curved surface which is curved inward according to the outer curved surface of the blank, that is, the middle hole is gradually reduced from the bottom to the top, so that the cross-sectional area of the whole blank is gradually increased from the bottom to the top or substantially consistent. It forms a sequential solidification at the time of casting without causing casting defects, and solves the problem that the conventional casting method easily forms casting defects.
  • the design also requires the thickness of the working layer of the roll according to the specific working conditions.
  • the blank is designed into two parts: the outer working layer and the inner layer, so that the composite layer of the inner layer 3-1 and the outer layer 3-2 are Gradually shrinks upwards to the inwardly curved inner curved state; inner and outer design divides the curved surface 3-4 diameter from bottom to top Gradually reduce and smooth out to ensure smooth release.
  • the thickness of the outer working layer of the blank can be further increased by 5mm to 20mm on the basis of the reserved machining allowance, so as to fully guarantee the repair amount when the heavy vehicle is used.
  • the weight ratio of the outer working layer to the inner layer of the blank is designed to be ⁇ 1.2:1.
  • the inner and outer boundary surfaces 3-4 in the rough design disappear after casting and melting, forming a composite bonding layer of two layers of two layers of outer and inner layers.
  • the broken line 3-3 in Fig. 3 shows the actual required roll product, and the center hole of the finished roll product is a cylindrical hole.
  • the mold design is carried out according to the shape of the outer curved surface and the mesa surface of the roll blank design and the required machining allowance, and the mold design is two parts of casting inner shape and casting outer shape; casting inner type 4-2
  • the design is to gradually reduce from the bottom to the inner curved and the lower end of the inner curved surface.
  • the cast shape is designed as the inner shape of the cast outer shape and the outer shape of the cast outer shape, and the inner cast shape 4-1 is to design the boundary surface and the upper end surface.
  • the outer shape of the outer casting is 5-1, which is the outer curved surface and the upper end surface of the blank.
  • the outer shape of the casting When assembled, the outer shape of the casting is placed on the casting inner shape from the top to the bottom, and the casting shape of the inner layer is formed.
  • 4-1 is assembled with the cast inner type 4-2 to form the inner layer cavity 4-3 of the blank, and the cast outer shape 5-1 of the outer layer is assembled with the inner layer 3-1 and the cast inner type 4-2 which have been cast and solidified.
  • the outer layer cavity 5-3 is formed, and the boundary curved surface of the solidified inner layer 3-1 forms the inner and outer boundary surface 5-2, thereby forming the entire blank mold.
  • the composite materials used in the smelting are designed in two ways, each casting a product of different materials.
  • One is a high chromium cast iron outer layer and a cast steel inner layer composite material; the other is an alloy ductile iron outer layer and a ductile iron inner layer composite material.
  • the two composite materials can make the casting shrinkage of the inner layer and the outer layer the same or similar, so that the solidification bonding ratio of the inner layer and the outer layer is uniform.
  • the cast inner type 4-2 is first assembled with the inner cast outer shape 4-1, and the inner cast outer shape 4-1 is placed on the cast inner type 4-2 from the top to the bottom to form a blank.
  • the layer cavity 4-3 is sealed by the sealing device of 4-4 and the mold positioning device of 4-5, and the smelted inner metal molten metal is poured into the inner cavity 4-3 of the blank, and waits After the inner metal melt is solidified, the cast outer shape 4-1 of the inner layer is removed when the metal solidification temperature is maintained at 850 ° C to 950 ° C, and the outer cast shape 5-1 is quickly or quickly loaded.
  • a temperature detector is arranged in the foundry sand type, and the solidification temperature of the inner layer metal can be obtained by the temperature detector Therefore, a casting having a weight of less than 500 kg can also be judged by detecting the temperature of the molten metal in the riser. Since the cross-sectional area of the inner and outer layers of the design is gradually increased or substantially uniform from the bottom to the top, the molten metal is sequentially solidified, thereby obtaining an ideal bimetal composite casting roll blank.
  • the roll having a small residual ratio after the roller is repeatedly re-carried to produce a single metal roll blank.
  • the casting of the inner and outer castings is about to be smelted and cast into the outer metal melt, which can also be sequentially solidified to obtain the desired roll blank.
  • another embodiment of the present invention provides a single metal material casting profile roll.
  • the cast profiled roll is also a curved shape with a large diameter at both ends and a small intermediate diameter, and has a middle hole along the central axis of the roll, which is realized by the following preparation method:
  • Blank design According to the curved shape of the single-metal material roll body with large diameter at both ends and small intermediate diameter, the outer curved surface and the upper and lower end faces of the blank are gradually reduced from the bottom to the inner curved surface according to the outer curved surface of the finished product.
  • the end face is added with a machining allowance, and the middle hole is designed to be gradually reduced from the bottom to the inner curved surface in accordance with the outer curved surface of the blank.
  • the cross-sectional areas of the above two designs gradually increase or remain consistent from bottom to top.
  • Casting and casting of single metal materials casting design according to the shape of the outer curved surface and the mesoporous surface of the roll blank design and the required machining allowance.
  • the casting design is cast inner type 6-2 and cast outer type 6-1.
  • Two parts; the cast inner type 6-2 is designed to be gradually reduced from the bottom to the inner curved inner and lower end faces, and the cast outer shape 6-1 is designed such that the outer curved surface of the blank is gradually reduced from the bottom to the bottom.
  • the smelted single metal melt is poured into the blank cavity 6 formed by casting the outer shape 6-1 and the cast inner type 6-2, and positioning and sealing by the mold positioning device 6-5 and the sealing device 6-4.
  • the casting process of the single metal casting profile roll is completed after the molten metal solidifies.
  • the single-metal material casting profile roll of the invention gradually increases or maintains the cross-sectional area of the blank and the mesopores from bottom to top, and forms a solidification well during casting, thereby increasing the diameter of both ends of the roll body,
  • the casting quality of a curved surface with a small intermediate diameter reduces casting defects.
  • the conventional blanking process is performed on the cast blank of the composite casting profiled roll and the cast profiled roll, that is, annealing, roughing, suitable heat treatment and finishing, to obtain a finished roll.
  • Austempering treatment was carried out when an alloy ductile iron material was used.
  • a plurality of convexities may be arranged on the inner wall of the cast iron sand box. Iron parts are added to increase the connection strength between the sand box and the sand mold. It is also possible to provide a steel skeleton in the outer sand mold to increase the strength of the sand mold. In order to increase the solidification speed, graphite powder or silica sand may be incorporated into the sand mold, or a small amount of tantalum powder may be added to the paint.
  • the composite of the high chromium cast iron outer layer and the cast steel inner layer composite material used in the composite casting profiled roll of the invention has the advantages that the high chromium cast iron has good wear resistance, impact resistance, chilling heat resistance and good hardening. Sex, cast steel has high strength and high toughness, and the casting shrinkage of the two is the same or similar, which can make the inner and outer layers of the composite casting well combined.
  • the specific composition of the composite material is designed as follows:
  • High chromium cast iron outer layer C: 2.0% to 2.6%, Si: 0.2% to 0.5%, Mn: 0.6% to 1.0%, Cr: 11.0% to 18.0%, Ni: 0.5% to 1.5%, Mo: 0.5% ⁇ 1.5%, W: 0.5% to 1.5%, Zr: 0.1% to 0.3%, Nb: 0.05% to 0.15%, Ti: 0.05% to 0.15%, RE: 0.05% to 0.15%, P: ⁇ 0.030%, S: ⁇ 0.025%, the balance being Fe and unavoidable impurities.
  • the content of Mo+W+Zr is 1.2% or more and 2.2% or less by mass percentage
  • the content of Nb+Ti+RE is 0.10% or more and 0.40% or less by mass percentage
  • the inner layer of cast steel For casting carbon steel or low alloy cast steel.
  • C and Cr are the most basic and important alloying elements in high chromium materials.
  • the amount of the carbide determines the amount of carbide, the relative amount of M 7 C 3 carbide and total carbide, hardness and toughness, and the hardenability of the material.
  • About 50% of the Mo element enters Mo 2 C in each phase of the high chromium material, and about 25% enters the M 7 C 3 type carbide, which can effectively improve the hardness and wear resistance of the material.
  • about 23% of the matrix is dissolved into the matrix, which significantly improves the hardenability of the material.
  • the bonding force between the W atom and the C atom is large, and the stability of the martensite pyrolysis is improved, thereby improving the red hardness.
  • Part of the W carbide is dissolved into the matrix during high temperature quenching to improve the hardenability of the material.
  • the Ni element strengthens the matrix and improves the overall properties of the material, improving the hardenability.
  • the addition of Zr can effectively improve the strength, hardness and red hardness of the material.
  • Ti can refine its eutectic structure to form a stable fine TiC nucleus.
  • Nb a hard phase Nb(CN) particle with high hardness (2000 HV), high melting point, small regular particle size and uniform dispersion can be precipitated in the matrix, which can effectively control the solidification segregation of the alloy and improve its comprehensive performance.
  • Ni or Cr To save the role of Ni or Cr.
  • the inner layer composition of the cast steel is designed according to the specific high chromium cast iron composition, and the conventional engineering cast carbon steel or low alloy cast steel can be selected.
  • the profiled rolls prepared by the high chromium cast iron outer layer and the cast steel inner layer composite material are mainly used for the equipment such as a welded pipe rolling mill, a cold-formed steel rolling mill, a steel pipe straightening machine and the like.
  • Another composite material employed in the present invention is an alloy ductile iron outer layer and a ductile iron inner layer. Austempered The alloyed iron of fire has good wear resistance, impact resistance, chilling resistance and good hardenability. Ductile iron has high strength and high toughness, and both have the same or similar casting shrinkage.
  • the specific composition design is as follows:
  • the composition of the outer layer of the alloy ductile iron is: C: 3.0% to 3.8%, Si: 1.4% to 1.8%, Mn: ⁇ 0.35%, Ni: ⁇ 2.5%, Cu: 0.4% to 1.0%, and Mo: 0.3%. 1.0%, Cr: 0.1% to 0.3%, B: ⁇ 0.08%, Mg: 0.04% to 0.10%, Bi: 0.0004% to 0.0005%, Sb: 0.0002% to 0.0003%, P: ⁇ 0.04%, S: ⁇ 0.02%, the rest is Fe and unavoidable impurities.
  • the content of Ni+Cu is 0.4% or more and 2.5% or less by mass percentage, and the content of Cr+B is 0.05% or more and 0.25% or less by mass percentage;
  • the composition of the inner layer of ductile iron is: C: 3.0% to 3.8%, Si: 2.2 to 2.7%, Mn: ⁇ 0.35%, Cu: 0.4% to 0.6%, Mg: 0.04% to 0.10%, P: ⁇ 0.04%, S: ⁇ 0.02%, and the rest It is Fe and inevitable impurities. among them,
  • C is a graphitization forming element.
  • the C content is increased, on the one hand, the precipitation of cementite is hindered, and on the other hand, the number of graphite cores is increased, the graphite can be refined, and the roundness of the graphite ball can be improved.
  • the C content be selected from 3.0% to 3.8%.
  • Si not only increases the eutectoid transformation temperature, but also widens the temperature range of eutectoid transformation and shortens the incubation period of pearlite and bainite.
  • the performance of bainite ductile iron increases with the increase of silicon content.
  • the increase of silicon content can make the graphite sphere diameter smaller, and silicon can promote bainite transformation and form fine needle-shaped bainite, thus improving needle shape.
  • the overall performance of the organization when the silicon content is too high, ferrite is formed, so Si is selected between 1.4% and 1.8% depending on the specific working conditions of the roll.
  • Mn is a reverse graphitization element, which combines with sulfur and oxygen to form MnS and MnO in the alloy ductile iron. Therefore, the main function of Mn is to eliminate the harmful effects of sulfur and oxygen in molten iron.
  • Mn is an element which is easily segregated.
  • S is a counter-graphitization element, S high will inevitably consume more spheroidizing agent, because the spheroidizing elements are strong desulfurizing agents, first desulfurization after addition, and then spheroidizing. Practice has proved that even when magnesium, calcium, zirconium and rare earth elements are added when the amount of S is high, it is impossible to obtain Good spheroidization effect, which leads to performance degradation.
  • the S content in the ductile iron should be as low as possible, so the setting S is ⁇ 0.02%.
  • Cr is one of the most intense carbide forming elements, and the amount of carbide increases with the increase of Cr content, so that the hardness is increased and the depth of the hard layer is deepened, so that the wear resistance is correspondingly increased. When it is multi-alloyed with elements such as molybdenum, it is particularly prominent. However, Cr is also a counter-graphitization element. The excessive Cr content affects the overall performance of spheroidization, and it is suitable to set Cr between 0.1% and 0.3%.
  • B forms a high hardness of boron carbide, which can significantly improve the wear resistance of the alloy ductile iron, but B is also a counter-graphitization element, and is set to ⁇ 0.08% according to the experimental result B.
  • the content of Cr+B is set to be greater than or equal to 0.05% and less than or equal to 0.25% by mass percentage.
  • Ni is the main alloying element for expanding the ⁇ phase region, forming and stabilizing austenite.
  • Ni does not form carbides with carbon, but is solid-solubilized in iron to stabilize and refine the pearlite structure. It has been proved that Ni is effective in increasing the content of pearlite in the large-section ductile iron and increasing the tensile strength of the core.
  • Ni is a rare metal, and the excessive Ni content makes the cost increase greatly, which makes the market difficult to accept. It should be determined according to the specific service conditions of different rolls, so Ni is set to ⁇ 2.5.
  • Cu promotes graphitization in eutectic transformation, and its graphitization ability is about 30% of silicon, which can lower the critical temperature of austenite transformation and promote the formation of pearlite, which is beneficial to reduce or eliminate the formation of free cementite, greatly reducing
  • the tendency of white mouth at the thin wall of the casting improves the toughness of the ductile iron, and at the same time strengthens and refines the ferrite in the pearlite and the pearlite, thereby improving the hardness and strength of the casting.
  • Mo and Mn the effect of improving hardenability is better.
  • an excessively high Cu content tends to increase the brittle fracture of the material when it is in a hot state. Therefore, Cu is set between 0.4% and 1.0%.
  • the content of Ni+Cu is set to be 0.4% or more and 2.5% or less by mass percentage.
  • Mo is a powerful pearlite forming agent and has a significant influence on the basic structure of the alloy ductile iron. When the Mo content in the cast iron reaches 0.5% or more, the matrix structure is completely converted into pearlite. When the Mo content is increased, the austenite decomposition of the alloy ductile iron is suppressed to form a needle-shaped bainite structure. Mo is also a rare metal. The excessive Mo content makes the cost increase greatly, which makes the market difficult to accept. It should be determined according to the specific service conditions of different rolls, so the Mo is set to 0.3% to 1.0%. The micro-addition of Bi and Sb can effectively improve the spheroidization quality, especially for the single-weight roll, which can significantly improve the spheroidization rate of graphite and improve the roundness of the graphite ball.
  • the profiled rolls produced by the alloy ductile iron outer layer and the ductile iron inner layer composite are mainly used for hot rolling seamlessly. Steel pipe sizing machine and reducer and other equipment.
  • the steel tube prepared by the invention and the profiled roll for cold-formed steel production adopt a simple and practical double metal double-external casting method, and the roll blank is changed into a structure suitable for casting sequential solidification by using the middle hole of the roll, and the double external casting is realized.
  • Bimetallic composite casting The method has the advantages of simple and easy operation, and the profiled roll has a sufficiently thick working layer and a high-strength and high-toughness core which are wear-resistant, impact-resistant, and resistant to chilling heat, which fully satisfies the use requirements. Due to the low alloying of the core, not only alloying elements such as Cr, Ni, Mo, and W are saved, but also the mechanical properties of the core are increased.
  • the working layer of the profiled roll uses a series of high-chromium cast iron and alloy ductile iron, which meets the requirements for various service conditions in the production of steel pipes and cold-formed steel mills.
  • the single-metal material casting profiled roll of the invention has a good design, and forms a good sequential solidification during casting, reduces casting defects, improves the casting quality, and satisfies the performance requirements of the rolling mill production on the roll.
  • the working layer material designed and prepared by the invention is a steel straightening roller, a welded pipe and a cold-formed steel roll of high chromium cast iron, and the use performance reaches the forging D2 (X155CrVMo12-1, SKD11) cold work die steel and forged H13 (X40CrMoV5-1, SKD61). ) Performance index of similar rolls for hot work die steel.
  • the material utilization rate is more than 30% higher than forging, which has achieved good results in energy saving and material saving.
  • the following embodiments uniformly provide 3 to 4 metal skeletons in the cast shape of the roll working layer to increase the joint strength between the sand box and the sand mold; 5% to 10 are added to the mold. % of graphite powder, adding some common knowledge of the powder to the coating to increase the solidification speed of the mold blank.
  • the machining allowance of the outer thickness of the profiled roll blank is increased by 5 mm to 20 mm, and the weight ratio of the outer working layer of the blank to the inner layer is ⁇ 1.2:1.
  • a conventional austempering heat treatment was carried out when an alloy ductile iron material was used.
  • the present embodiment is a ⁇ 720 seamless steel tube unit heat treatment line straightening machine roll, each set of 6 pieces, using a high chromium cast iron outer layer and cast steel inner layer composite material.
  • the existing forged 9Cr2MoV roll blank of one of the comparative examples is a free-forged cylinder having a weight of about 8948 kg and a service life of one year.
  • the full-profile machining allowance design has a blank weight of about 4681 kg.
  • the size of the finished product (Fig. 3) of this embodiment is: the maximum diameter of the upper and lower ends is ⁇ 994mm, the minimum diameter of the middle is ⁇ 880mm, the inner hole is ⁇ 480mm, the height of the roller is 1100mm, and the weight is 4060kg/piece.
  • the size of the blank design (Fig. 3) of this embodiment is: the outer surface of the outer curved surface is ⁇ 1034mm, the middle minimum is ⁇ 910mm, the lower end is ⁇ 1013mm, and the lower end is the lower end. ⁇ 471mm, gradually narrowed upward to ⁇ 344mm at the upper end, ⁇ 774mm at the lower end of the design boundary surface, and the curved surface that gradually reduces the smooth transition from bottom to top gradually narrows to the upper end of ⁇ 665mm, the outer layer weight is 2880kg, and the inner layer weight is 2235kg.
  • a double outer mold was prepared according to the above dimensions, that is, a cast inner type 4-2, an inner cast type 4-1 (Fig. 4) and an outer cast type 5-1 (Fig. 5) were prepared. Referring to Figure 4, the cast inner shape 4-2 and the inner cast outer shape 4-1 are first assembled and sealed, so that the inner cast type 4-1 and the cast inner type 4-2 are assembled.
  • the inner cavity of the blank is 4-3; the outer layer material of the high chromium cast iron and the inner layer material of the cast steel are simultaneously smelted by using two electric furnaces, and the molten inner layer of the cast steel is poured into the inner cavity 4-3 of the blank,
  • the temperature detector to be placed in the mold is displayed at 850 ° C, the cast outer shape 4-1 of the inner layer is removed, and the cast outer shape 5-1 of the upper outer layer is quickly installed. Referring to FIG. 5, the smelting is good.
  • the outer layer of high chromium cast iron melt is poured into the outer cavity 5-3 of the blank, and after solidification, the entire casting process of the profiled roll is completed.
  • the cross-sectional area design of the inner and outer layers is gradually increased from the bottom to the top, sequential solidification is achieved, thereby obtaining a 100% qualified bimetal composite casting straightener roll blank.
  • the weight of the composite roll obtained was 5115 kg/piece, which was 57.1% of the forged billet, and the material utilization rate was increased by 42.8%; 109% of the weight of the blank was designed for the full profiling allowance. Not only guaranteed 100% pass rate.
  • the inner layer of cast steel saves a lot of metals such as Cr, Ni, Mo, Zr, and reduces the production cost.
  • the finished profiled roll blank is subjected to conventional annealing, roughing, heat treatment and finishing to obtain a finished roll.
  • the chemical composition of the outer layer is: C: 2.12%, Si: 0.40%, Mn: 0.78%, Cr: 16.10%, Ni: 1.15%, Mo: 1.30%, W: 0.5, Zr: 0.30%, Nb: 0.10%, Ti: 0.08%, RE: 0.05%, P: 0.023%, S: 0.017%, the balance being Fe and unavoidable impurities.
  • the hardness of the working face of the roll is 56.5HRC ⁇ 57.6HRC, and the service life can be increased to more than 2 years. See Table 1 for comparison of the effect of rolling the same steel pipe and 9Cr2MoV forging steel roll in this embodiment.
  • the cast profiled rolls of the present invention are rolled in the same manner as the existing forged 9Cr2MoV rolls of one of the comparative examples, in the same case of the straightening amount of 1 mm in the radial direction of the rolls.
  • the amount is more than twice. Life expectancy has also doubled.
  • the embodiment of this embodiment The weight of the product roll was 4060 kg/piece, and the weight of the roll of one of the comparative examples was about 8948 kg, which was more than double that of the present invention.
  • the weight of the roll of Comparative Example 2 was 4681 kg, which was also 621 kg more than the present example. Therefore, the invention not only has a long service life but also saves a lot of materials.
  • the present embodiment is for manufacturing a ⁇ 250 seamless steel tube unit heat treatment line straightening machine roll, each set of 6 pieces, using a high chromium cast iron outer layer and a cast steel inner layer composite material.
  • the existing forged X155CrVMo12-1 roll blank of one of the comparative examples is a free forged cylinder having a weight of about 1530 kg.
  • the full profile plus machining allowance design of the second comparative example has a blank weight of about 990 kg.
  • the dimensions of the finished product of this embodiment are: the maximum diameter of the upper and lower ends is ⁇ 572mm, the minimum diameter of the middle is ⁇ 480mm, the inner hole is ⁇ 240mm, the height of the roller is 660mm, and the weight is 806kg/piece.
  • the size of the blank (refer to FIG. 3) of this embodiment is designed as follows: the outer surface of the outer curved surface is ⁇ 612mm, the middle minimum is ⁇ 510mm, the lower end is ⁇ 592mm, the lower end of the middle hole is ⁇ 235mm, the upper end is gradually narrowed to the upper end of ⁇ 148mm, and the design boundary is The lower end of the curved surface is ⁇ 436mm, and the curved surface which strictly follows the diameter from bottom to top and gradually reduces the smooth transition gradually narrows to the upper end of ⁇ 378mm, the designed outer layer weight is 614kg, and the inner layer weight is 486kg.
  • the cast inner type 4-2, the cast outer form 4-1 of the inner layer (Fig. 4) and the cast outer form 5-1 of the outer layer (Fig. 5) were prepared.
  • the cast inner shape 4-2 and the inner cast outer shape 4-1 are first assembled and sealed, so that the inner cast type 4-1 and the cast inner type 4-2 are assembled.
  • the inner cavity 4-3 of the blank (Fig. 4); the high-chromium cast iron outer layer material and the cast steel inner layer material are simultaneously smelted by two electric furnaces.
  • the smelted molten steel inner layer melt is poured into the inner layer cavity 4-3 (Fig. 4), and the inner shape of the inner layer is to be set when the temperature detector in the mold is displayed at 950 °C. -1 (Fig.
  • a conventional processing process is performed on the profiled roll blank to obtain a finished roll.
  • the chemical composition of the outer layer of the roll is: C: 2.20%, Si: 0.38%, Mn: 0.68%, Cr: 17.10%, Ni: 1.25%, Mo: 1.00%, W: 1.00%, Zr: 0.20 %, Nb: 0.15%, Ti: 0.10%, RE: 0.10%, P: 0.023%, S: 0.017%, the balance being Fe and unavoidable impurities.
  • the working face hardness of the roll is 56.8HRC ⁇ 57.4HRC.
  • the same steel pipe in this embodiment is better than the X155CrVMo12-1 forged steel roll, and the effect is better than that of the forged steel roll.
  • the performance comparison is shown in Table 2.
  • Roll material, molding method 1mm rolled steel pipe tonnage in the radial direction of the roll X155CrVMo12-1 forged steel roll 1.0 million tons Casting shaped roll of the invention 12,000 tons
  • the cast profiled rolls of the present invention are compared with the existing forged X155CrVMo12-1 rolls of one of the comparative examples, in the same case of the straightening amount of 1 mm in the radial direction of the rolls.
  • the rolling capacity has increased by 0.2 million tons.
  • the weight of the finished roll of the present embodiment was 806 kg/piece, and the weight of the roll of one of the comparative examples was about 1530 kg, which was almost double that of the present invention; and the weight of the roll of the second comparative example was 990 kg, which was also the same as the present example. More than 200kg.
  • the invention saves materials and has high production efficiency.
  • the present embodiment is a ⁇ 406 welded steel pipe precision forming roll, each set of 2 pieces, which is made of a high chromium cast iron outer layer and a cast steel inner layer composite material.
  • the prior art is forging X155CrVMo12-1 rolls, which are free-forged cylinders and weigh about 3180 kg.
  • the dimensions of the finished product of this embodiment are: the maximum diameter of the upper and lower ends is ⁇ 926mm, the minimum diameter of the middle is ⁇ 720mm, the inner hole is ⁇ 340mm, the height of the roller is 530mm, and the weight is 1657kg/piece.
  • the upper limit of the surface of the implementation is ⁇ 966mm
  • the middle minimum is ⁇ 750mm
  • the lower end is ⁇ 946mm
  • the lower end of the middle hole is ⁇ 334mm
  • the upper end is gradually reduced to the upper end is ⁇ 255mm
  • the lower end of the design boundary surface is ⁇ 644mm, strictly follow the diameter from bottom to
  • the surface on which the smooth transition is gradually reduced is gradually reduced upward to ⁇ 598 mm
  • the outer layer weight is 1262 kg
  • the inner layer weight is 909 kg.
  • This embodiment produces a cast inner type 4-2 (Fig. 4), a cast outer form 4-1 (Fig. 4) of the inner layer, and a cast outer form 5-1 (Fig. 5) of the outer layer in accordance with the above dimensions.
  • the cast inner shape 4-2 and the inner cast outer shape 4-1 are assembled and positioned and sealed, and the blank inner layer cavity 4-3 is formed after assembly (Fig. 4). Simultaneously smelting high chromium cast iron and cast steel materials.
  • the smelted molten steel molten metal is poured into the inner cavity 4-3 of the blank, and when the temperature detector disposed in the mold is displayed at 900 ° C, the cast outer shape of the inner layer is removed 4-1, rapidly The casting outer shape 5-1 of the upper outer layer is installed, and the smelted outer high chromium cast iron melt is poured into the outer layer cavity 5-3 (Fig. 5) to complete the casting process of the profiled roll.
  • the sequential solidification is fully achieved and a qualified roll blank is obtained.
  • the weight of the roll blank is 2171kg/piece, which is 68.3% of the forged roll blank, and the material utilization rate is increased by 31.7%; the blank weight is designed to be 108% of the total copying allowance, but the 100% pass rate is guaranteed. Since the inner cast steel saves a large amount of alloy material, the production cost is greatly reduced.
  • the composite casting profile roll blank is processed and heat treated to obtain a finished roll.
  • the chemical composition of the outer layer of the roll was measured by mass percentage: C: 2.59%, Si: 0.21%, Mn: 0.63%, Cr: 17.90%, Ni: 1.45%, Mo: 1.40%, W: 0.50%, Zr: 0.15%, Nb: 0.15%, Ti: 0.05%, RE: 0.10%, P: 0.024%, S: 0.013%, the balance being Fe and unavoidable impurities.
  • the hardness of the working face of the roll is 59.8HRC ⁇ 60.4HRC, and the rolling pipe is 150,000 tons when the roll wears 1mm in the radial direction, reaching the level of forged X155CrVMo12-1 roll.
  • the present embodiment is a ⁇ 147 welded steel pipe precision forming roll, each set of 2 pieces, using a high chromium cast iron outer layer and a cast steel inner layer composite material.
  • the existing original forged X155CrVMo12-1 roll blank is a free forged cylinder and weighs about 510 kg.
  • the dimensions of the finished product of this embodiment are: the maximum diameter of the upper and lower ends is ⁇ 576mm, the minimum diameter of the middle is ⁇ 520mm, the inner hole is ⁇ 280mm, the height of the roller is 210mm, and the weight is 261kg/piece.
  • the blank size of the embodiment is: the outer surface of the outer curved surface is ⁇ 595mm, the middle minimum is ⁇ 540mm, the lower end is ⁇ 595mm, the lower end of the middle hole is ⁇ 278mm, the upward direction is gradually reduced to the upper end is ⁇ 211mm, and the lower end of the design boundary surface is ⁇ 436mm, diameter
  • the surface of the smooth transition from the bottom to the top is gradually reduced upward to ⁇ 379 mm
  • the outer layer weight of the roll is 231 kg
  • the inner layer weight is 139 kg.
  • This embodiment produces a cast inner type 4-2 (Fig. 4), an inner cast type 4-1 (Fig. 4), and an outer cast type 5-1 (Fig. 5) according to the above dimensions.
  • the cast inner type 4-2 and the inner cast type 4-1 are assembled and sealed, and the inner cast type 4-1 and the cast inner type 4-2 are assembled to form a blank.
  • Layer cavity 4-3 (Fig. 4
  • the weight of the roll blank is 370kg/piece, which is 72.5% of the forged roll blank, and the material utilization rate is increased by 27.5%; the blank weight is designed to be 104% of the total copying allowance, but the quality is much better than the full profile. Design blanks.
  • the inner cast steel saves a lot of alloy materials, which greatly reduces the production cost.
  • the roll blank is subjected to annealing, roughing, heat treatment and finishing to obtain a finished roll.
  • the chemical composition of the outer layer of the roll is: C: 2.60%, Si: 0.49%, Mn: 0.93%, Cr: 11.20%, Ni: 0.51%, Mo: 1.0%, W: 0.8%, Zr: 0.30 %, Nb: 0.05%, Ti: 0.15%, RE: 0.05%, P: 0.020%, S: 0.014%, and the balance being Fe and unavoidable impurities.
  • the hardness of the working face of the roll is 58.2HRC ⁇ 61.1HRC, and the wear of the roll in the radial direction of 1mm can be 100,000 tons of welded pipe, which is equivalent to the level of forged X155CrVMo12-1 roll.
  • the present embodiment is a ⁇ 340 hot-rolled seamless steel pipe sizing machine roll, which uses an alloy ductile iron outer layer and a ductile iron inner layer composite material.
  • the existing rolls are cast Ni3Mo1 ductile iron rolls, the heat treatment process is normalized, and the impact toughness of physical anatomy is 30KJ/m 2 .
  • the dimensions of the finished product of this embodiment are: the maximum diameter of the upper and lower ends is ⁇ 641 mm, the minimum diameter of the middle is ⁇ 534 mm, the inner hole is ⁇ 190 mm, the height of the roller is 420 mm, and the weight is 660 kg/piece.
  • the outer curved surface of the blank is ⁇ 661mm, the middle minimum is ⁇ 554mm, the lower end is ⁇ 661mm, the lower end of the middle hole is ⁇ 193mm, the upper end is gradually reduced to ⁇ 134mm, and the lower end of the design boundary surface is ⁇ 417mm, strictly following the diameter. From bottom to top, the principle of smooth transition is gradually reduced, and the curved surface is gradually narrowed upward to ⁇ 358mm at the upper end, 540kg of the outer layer of the roll, and 313kg of the inner layer.
  • the cast inner shape 4-2 (Fig. 4), the cast outer shape 4-1 (Fig. 4) of the inner layer, and the cast outer shape 5-1 (Fig. 5) of the outer layer were produced according to the above dimensions.
  • the cast inner mold 4-2 and the inner cast outer shape 4-1 are assembled and sealed to form a blank inner layer cavity 4-3 (Fig. 4); and the alloy ductile iron and ductile iron are simultaneously smelted. .
  • the smelted ductile iron melt is poured into the inner cavity 4-3 of the blank, and when the temperature detector disposed in the mold is displayed at 920 ° C, the cast outer shape of the inner layer is removed 4-1, rapidly The upper outer casting shape 5-1 is installed, and the smelted outer alloy ductile iron melt is poured into the outer layer cavity 5-3 (Fig. 5) to complete the hot rolling seamless steel pipe sizing machine roll.
  • the casting process of the blank In this embodiment, since the sequential solidification is achieved, a qualified roll blank is obtained.
  • the weight of the roll blank is 853kg/piece, which is 108% of the weight of the blank for the full profiling allowance, but the quality is much better than the full-profile design blank.
  • each casting of inner cast iron can save 9kg of Ni and 3kg of Mo, which reduces the material cost.
  • the chemical composition of the outer working layer of the roll is: C: 3.65%, Si: 1.72%, Mn: 0.30%, Ni: 2.0%, Cu: 0.4%, Mo: 0.70%, Cr: 0.10%, B. : 0.05%, Mg: 0.06%, Bi: 0.0004%, Sb: 0.0002%, P: 0.03%, S: 0.015%, and the balance being Fe and unavoidable impurities.
  • the chemical composition of the inner layer is: C: 3.2%, Si: 2.55%, Mn: 0.34%, Cu: 0.4%, Mg: 0.06%, P: 0.023%, S: 0.017%, and the rest is Fe and Inevitable impurities.
  • the hardness of the working face of the roll is 66HS ⁇ 68HS, and the impact toughness of the physical anatomy is 100KJ/m 2 .
  • the roll wears 1mm in the radial direction and 8000 rolled steel pipes.
  • the existing cast Ni3Mo1 ductile iron roll wears 1mm in the radial direction and can roll 7000 identical steel pipes.
  • the rolling amount of 1000 steel pipes was increased under the same conditions as compared with the conventional cast Ni3Mo1 ductile iron roll.
  • this embodiment is a ⁇ 250 hot-rolled seamless steel pipe sizing machine roll, which adopts a high chromium cast iron outer layer and a cast steel inner layer composite material.
  • the existing Ni3Mo1 ductile iron roll is used.
  • the size of the finished roll of this embodiment is: the maximum diameter of the upper and lower ends is ⁇ 484 mm, the minimum diameter of the middle is ⁇ 420 mm, the inner hole is ⁇ 160 mm, the height of the roll is 265 mm, and the weight is 241 kg/piece.
  • the outer curved surface of the blank of the present embodiment is approximated to the finished curved surface, and the upper end of the design is ⁇ 498mm, the middle minimum is ⁇ 436mm, the lower end is ⁇ 498mm, the lower end of the middle hole is ⁇ 168mm, the upward direction is gradually reduced to the upper end ⁇ 111mm, and the lower end of the design boundary surface is ⁇ 322mm, the diameter is from below.
  • the smooth transition is gradually reduced, and the curved surface is gradually reduced upward to ⁇ 284mm at the upper end; the outer layer weight of the design blank is 204kg, and the inner layer weight is 109kg.
  • the cast inner shape 4-2 (Fig. 4), the cast outer shape 4-1 (Fig. 4) of the inner layer, and the cast outer shape 5-1 (Fig. 5) of the outer layer were produced according to the above dimensions.
  • the cast inner mold 4-2 and the inner cast outer shape 4-1 are assembled and sealed to form a blank inner layer cavity 4-3 (Fig. 4); at the same time, high chromium cast iron and cast are smelted. steel.
  • the smelted molten steel molten metal is poured into the inner cavity 4-3 of the blank, and when the temperature detector disposed in the mold is displayed at 910 ° C, the cast outer shape of the inner layer is removed 4-1, rapidly The upper outer casting shape 5-1 is installed, and the smelted outer high chromium cast iron melt is poured into the outer layer cavity 5-3 (Fig. 5) to complete the hot rolled seamless steel pipe sizing machine roll.
  • the casting process of the blank In this embodiment, the weight of the roll blank is 313 kg/piece, and the weight of the blank is designed to be 109% of the total copying allowance, but the 100% pass rate is guaranteed, and the quality is superior to the full-profile design blank.
  • the chemical composition of the outer layer of the roll is: C: 2.10%, Si: 0.21%, Mn: 0.65%, Cr: 18.00%, Ni: 1.50%, Mo: 0.50%. , W: 1.10%, Zr: 0.30%, Nb: 0.05%, Ti: 0.05%, RE: 0.10%, P: 0.020%, S: 0.014%, and the balance being Fe and unavoidable impurities.
  • the hardness of the working face of the roll is 73HS ⁇ 77HS.
  • the production effect of the composite casting profiled roll of this embodiment in the table is more than doubled and more than twice that of the first two rolls.
  • this embodiment is a ⁇ 720 hot-rolled seamless steel pipe four-roller sizing machine roll, which is a new unit and is the world's largest hot-rolled seamless.
  • Steel pipe sizing machine rolls It is an ultra-thick spheroidal graphite iron casting that is quite difficult to cast and heat treat.
  • An alloy ductile iron outer layer and a ductile iron inner layer composite material are used.
  • the dimensions of the finished product of this embodiment are: the maximum diameter of the upper and lower ends is ⁇ 1160mm, the minimum diameter of the middle is ⁇ 1108mm, the inner hole is ⁇ 330mm, the height of the roller is 400mm, and the weight is 2495kg/piece.
  • the design blank size of this embodiment is: the outer surface of the outer curved surface is ⁇ 1194mm according to the approximate finished curved surface, the middle minimum is ⁇ 1141mm, the lower end is ⁇ 1194mm, the lower end of the middle hole is ⁇ 366mm, the upward direction is gradually reduced to the upper end is ⁇ 277mm, and the lower end of the design boundary surface is ⁇ 730mm
  • the diameter of the smooth transition from bottom to top gradually decreases upward to ⁇ 676mm at the upper end; the outer layer weight is 2060kg, and the inner layer weight is 1090kg.
  • the cast inner shape 4-2 (Fig. 4), the cast outer shape 4-1 (Fig. 4) of the inner layer, and the cast outer shape 5-1 (Fig. 5) of the outer layer were produced according to the above dimensions.
  • the cast inner mold 4-2 and the inner cast outer shape 4-1 are assembled and sealed to form a blank inner cavity 4-3 (Fig. 4); two electric furnaces simultaneously smelt alloy ductile iron And ball iron.
  • the smelted ductile iron melt is poured into the inner cavity 4-3 of the blank, and when the temperature detector disposed in the mold is displayed at 880 ° C, the cast outer shape of the inner layer is removed 4-1, rapidly The cast outer shape 5-1 of the outer layer is loaded, and the smelted outer alloy ductile iron melt is poured into the outer layer cavity 5-3 (Fig. 5) to complete the casting process of the sizing machine roll blank.
  • the obtained composite roll blank weight is 3150kg/piece, which is basically equal to the design weight of the full-profile machining allowance casting blank, and the 100% pass rate is guaranteed.
  • each casting of the inner ductile iron can save 33kg of Ni and 11kg of Mo, saving raw materials and reducing production costs.
  • the finished sizing machine roll blank is subjected to conventional annealing, roughing, isothermal quenching and finishing to obtain a finished roll.
  • the chemical composition of the outer layer of the roll is: C: 3.80%, Si: 1.41%, Mn: 0.25%, Ni: 2.05%, Cu: 0.4%, Mo: 1.00%, Cr: 0.20%, B: 0.03% , Mg: 0.06%, Bi: 0.0004%, Sb: 0.0002%, P: 0.03%, S: 0.015%, and the balance being Fe and unavoidable impurities.
  • the chemical composition of the inner layer is: C: 3.75%, Si: 2.20%, Mn: 0.30%, Cu: 0.50%, Mg: 0.06%, P: 0.023%, S: 0.017%, and the rest are Fe and Inevitable impurities.
  • the hardness of the working face of the roll after isothermal quenching is 65HS ⁇ 69HS. After the installation test, the roll radial direction wears 1mm rolled steel pipe 7000 pieces, which meets the design requirements.
  • this embodiment is a ⁇ 89 seamless steel pipe single metal straightener roll, each set of 6 pieces, using high chromium cast iron material.
  • the existing forged X155CrVMo12-1 roll blank is a free forged cylinder and weighs approximately 427 kg. Since the roller needs to be repaired more than 6 times in use, the amount of repair is about 5 mm each time, and the roller itself is small in size and weight, so it is made of a single metal material.
  • the dimensions of the finished product of this embodiment are: the maximum diameter of the upper and lower ends is ⁇ 342 mm, the minimum diameter of the middle is ⁇ 297 mm, the inner hole is ⁇ 165 mm, the height of the roller is 440 mm, and the weight is 172 kg / piece.
  • the blank size of the embodiment is as follows: the outer surface of the outer surface is ⁇ 361mm, the middle minimum is ⁇ 317mm, the lower end is ⁇ 361mm, the lower end of the middle hole is ⁇ 157mm, and the diameter is gradually reduced from bottom to top to a smooth transition surface. Reduce to the upper end of ⁇ 119mm.
  • This embodiment produces a cast inner type 6-2 (Fig. 6) and a cast outer type 6-1 (Fig. 6) in accordance with the above dimensions.
  • the casting profile 6-1 is assembled with the casting profile 6-2 and the two molds are positioned and sealed using the mold positioning device 6-5 and the sealing device 6-4, and the mold is formed.
  • Blank cavity 6-3 Figure 6
  • the smelted high-chromium cast iron melt is poured into the blank cavity 6-3.
  • the cast shape 6-1 is removed to complete the casting process of the profiled roll.
  • the roll blank is subjected to annealing, roughing, heat treatment and finishing to obtain a finished roll.
  • the chemical composition of the roll body is expressed by mass percentage: C: 2.38%, Si: 0.35%, Mn: 0.91%, Cr: 17.90%, Ni: 1.2%, Mo: 0.89%, W: 1.1%, Zr: 0.1%, Nb: 0.015%, Ti: 0.10%, RE: 0.08%, P: 0.030%, S: 0.018%,
  • the rest are Fe and unavoidable impurities.
  • the hardness of the finished product roll surface is 58.2HRC ⁇ 59.9HRC.
  • the radial direction of the roll is 1mm, and the seamless steel pipe is 28,000 tons, which is 1.15 times that of the forged X155CrVMo12-1 roll.
  • the above embodiments of the present invention have all been put to practical use.
  • the effect of the actual application and the comparison of the data show that the composite casting profiled rolls and the cast profiled rolls prepared by the two casting methods of the present invention have much higher performance than the existing rolls.
  • the invention has high strength, high toughness and high wear resistance, as well as good impact resistance.
  • the service life of the rolls is greatly improved, which reduces production and maintenance costs and increases production efficiency.
  • the invention saves a large amount of metal materials from the blank and the mold design to the casting process, and also reduces the processing cost, and produces good economic benefits as well as energy saving and material saving effects.

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Abstract

一种铸造异型轧辊及其制备方法以及一种复合铸造异型轧辊及其制备方法，该复合铸造异型轧辊的结构是由内层（3-1）和外层（3-2）两部分复合而成，轧辊的辊身为曲面形状，轧辊中轴线上设置有用以装轴的中孔。该制备方法通过轧辊辊身的曲面设计和铸型设计，将铸型设计为铸造内型（4-2）和铸造外型（4-1,5-1）两部分，通过分别浇铸，制备出具有耐磨、耐冲击、耐激冷激热的辊身工作层和高强度高韧性芯部的复合铸造异型轧辊，满足了钢管以及冷弯型钢轧机等设备所用轧辊的服役条件要求，提高了轧辊的使用寿命，节约了合金材料，降低了制造成本。

Description

复合铸造异型轧辊及其制备方法 技术领域
本发明涉及轧辊铸造技术，尤其涉及一种异型轧辊采用复合结构铸造的制备方法，该制备方法采用双液双外型铸造方法制备钢管及冷弯型钢等轧机生产用异型轧辊。
背景技术
钢管及冷弯型钢生产用异型轧辊中的无缝钢管生产用定径机轧辊即定径辊、张力减径机轧辊即张减辊，钢管及圆钢斜辊式矫直机轧辊即矫直辊，以及焊接钢管机组中的大部分轧辊和冷弯型钢机组中的部分轧辊，均属于两端直径大、中间直径小的曲面类异型轧辊。这类异型轧辊的结构属于辊和轴分离型，即都有中孔，在中孔内装轴后安装到机架上使用。
上述异型轧辊是无缝钢管、焊接钢管及冷弯型钢生产中消耗量最大的工件，在大的压应力下承受滚动和滑动摩擦，并且承受轧材头部和尾部的反复冲击，有的还要承受高温轧材和冷却水的激冷激热作用，工作环境很恶劣。
这些异型轧辊按照使用温度可以分为两类：一类为低温使用，如矫直辊、焊接钢管及冷弯型钢轧辊等，基本都在常温下使用。只有热处理线温矫直时矫直辊要承受400℃～500℃轧材温度的作用，焊接钢管及冷弯型钢的焊接挤压轧辊还要承受轧材焊接时产生的高温作用。同时，上述二者均要受到冷却水的激冷作用。另一类为高温使用，如定径辊和张减辊，所作用的轧材温度一般为800℃～1100℃。
上述异型轧辊在使用中还要经过多次车、磨的修复。因此要求异型轧辊具有耐磨、耐冲击、耐激冷激热的足够厚的工作层，并且应和高强度、高韧性的芯部相结合。而这种理想状态下的异型轧辊应是由满足两种不同要求的双金属复合结构。但目前上述轧辊均为单金属制造，较难兼顾一种异型轧辊需要两种不同性能的要求。
上述矫直辊、焊接钢管及冷弯型钢轧辊还有规格品种繁多，同规格品种批量少，多数一张图纸只制作1～2件的特点。成品轧辊单重大的可达每件十 几吨，小的单重每件不足1公斤。国际上本技术领域目前通常使用锻造D2(X155CrVMo12-1、SKD11)冷作模具钢和锻造H13(X40CrMoV5-1、SKD61)热作模具钢制造异型轧辊。而锻造工艺均为自由锻成圆柱体，孔型和内孔都由机加工获得，材料利用率低至50％以下。同时由于上述模具钢的合金含量高，锻造和热处理难度大，工艺要求严格，无法实现双金属结构，而且材料和能耗大，生产成本高。
上述定径辊和张减辊，通常使用高合金球墨铸铁(一般为Ni3Mo1)制造，在球墨铸铁中添加了含量较高的Ni、Mo、Cr等合金元素，提高了球墨铸铁轧辊的耐磨性。但是由于加入了Cr、Mo等反球化元素，容易降低整体球化水平。又由于定径辊和张减辊属于壁厚不均匀的厚大球墨铸铁件，等温淬火难度大，因此常规使用正火工艺，所得贝氏体组织依赖含量较高的Ni、Cr、Mo等合金元素获得。但正火同样的工件，其强度、韧性均大大低于等温淬火件，在使用过程中经多次加工后所剩壁厚较薄时容易裂、碎。
虽然通过离心铸造也可以获得双金属结构的定径辊和张减辊，但离心铸造存在着如下局限：如需要制作金属模具。当制造单重较小的定径辊和张减辊时，需要制作多套模具，并且需要多台离心机同时工作，大大增加了生产成本。由于定径辊和张减辊的壁厚大，即轧辊的外径与内孔的直径差大，离心铸造的难度大。其所具有的两端直径大、中间直径小的曲面是离心铸造无法实现的，即铸造出的曲面无法从离心金属模中脱出。所以只能离心铸造出圆柱体，再进行加工。使轧辊的加工和材料消耗大大增加。
上述异型轧辊若采用全仿形毛坯和常规铸造方法，则容易因为中间直径小的部位先凝固，从而使下部补缩不足而产生缺陷造成废品。
发明内容
本发明为钢管及冷弯型钢轧机等设备所使用的异型轧辊制造提供一种复合铸造的异型结构轧辊，以及提供一种简单实用又能够保证质量的双液双外型异型轧辊的铸造方法，和一种铸造异型轧辊以及铸造异型轧辊的制备方法。本发明的复合铸造异型结构轧辊的技术方案如下：
本发明的复合铸造异型轧辊的辊身为两端直径大，中间直径小，辊身为曲面形状；所述曲面形状是由内层和外层两部分复合结合组成，内层和外层的复合结合层呈从下向上逐渐缩小为向内弯曲的曲面形状，沿轧辊的中轴线 具有一中孔，以在装轴时使用。
本发明的复合铸造异型轧辊采用两种复合材料,并且采用双液双外型铸造方法，其步骤如下：
毛坯设计：根据轧辊辊身两端直径大，中间直径小的曲面形状，将毛坯的外曲面和上下端面按照成品的外曲面和上下端面加上加工余量进行设计，中孔按照毛坯的外曲面设计为从下向上逐渐缩小为向内弯曲的内曲面。
将毛坯设计为内层和外层两部分，内层和外层两部分的复合结合层呈从下向上逐渐缩小为向内弯曲的内曲面形状，内层和外层的横截面面积从下往上逐渐增加或保持一致，内外层设计分界曲面的直径从下到上逐渐减小且圆滑过度。
铸型设计：根据轧辊毛坯设计的外曲面和中孔曲面形状以及所需加工余量进行铸型设计,铸型设计为铸造内型和铸造外型两部分；铸造内型设计为从下向上逐渐缩小为向内弯曲的内曲面中孔和下端面，铸造外型设计为内层的铸造外型和外层的铸造外型两个外型部分；内层的铸造外型为设计分界曲面和上端面，外层的铸造外型为毛坯外曲面和上端面。
冶炼：同时分别冶炼内层和外层两种所需金属熔液。
浇铸：先将铸造内型与内层的铸造外型进行组装，将内层的铸造外型从上而下套在铸造内型上形成毛坯内层型腔并密封好，将冶炼好的内层金属熔液浇入毛坯内层型腔中，待内层金属熔液凝固后，在金属凝固温度保持在850℃～950℃时将内层的铸造外型移开，快速装上外层的铸造外型形成毛坯外层型腔并密封好，将冶炼好的外层金属熔液浇入毛坯外层型腔中，待外层金属熔液凝固后，移开外层的铸造外型，完成复合铸造异型轧辊的浇铸过程，形成外层和内层两部分两种金属互熔的复合结合层。
加工:对铸造完成的异形轧辊毛坯进行常规的加工和热处理工艺。
本发明的复合铸造异形轧辊采用两种复合材料分别铸造不同材料的产品，一种为高铬铸铁外层和铸钢内层复合材料，其组成按质量百分比计为：高铬铸铁外层：C：2.0％～2.6％，Si：0.2％～0.5％，Mn：0.6％～1.0％，Cr：11.0％～18.0％，Ni：0.5％～1.5％，Mo：0.5％～1.5％，W：0.5％～1.5％，Zr：0.1％～0.3％，Nb：0.05％～0.15％，Ti：0.05％～0.15％，RE：0.05％～0.15％，P：≤0.030％，S：≤0.025％，其余为Fe和不可避免的杂质。其中：Mo+W+Zr的含量按质量百分比计为大于等于1.2％且小于等于2.2％，Nb+Ti+RE 含量按质量百分比计为大于等于0.10％且小于等于0.40％；铸钢内层为铸造碳钢或低合金铸钢。
另一种为合金球铁外层和球铁内层复合材料，合金球铁外层的组成按质量百分比计为：C：3.0％～3.8％，Si：1.4％～1.8％，Mn：≤0.35％，Ni：≤2.5％，Cu：0.4％～1.0％，Mo：0.3％～1.0％，Cr：0.1％～0.3％，B：≤0.08％，Mg：0.04％～0.10％，Bi：0.0004％～0.0005％，Sb：0.0002％～0.0003％，P：≤0.04％，S：≤0.02％，其余为Fe和不可避免的杂质。其中：Ni+Cu的含量按质量百分比计为大于等于0.4％且小于等于2.5％，Cr+B的含量按质量百分比计为大于等于0.05％且小于等于0.25％。球铁内层的组成按质量百分比计为：C：3.0％～3.8％，Si：2.2％～2.7％，Mn：≤0.35％，Cu：0.4％～0.6％，Mg：0.04％～0.10％，P：≤0.04％，S：≤0.02％，其余为Fe和不可避免的杂质。采用合金球铁时进行等温淬火热处理。
本发明的铸造异型轧辊及其制备方法的技术方案为采用一种金属材料铸造的异型轧辊。其特点在于异型轧辊的辊身为两端直径大，中间直径小的曲面形状,沿轧辊的中轴线具有一中孔。该铸造异型轧辊的制备方法在于如下步骤：
毛坯设计：根据轧辊辊身两端直径大，中间直径小的曲面形状，将毛坯的外曲面和上下端面按照成品的外曲面从下向上逐渐缩小为向内弯曲的内曲面状态，上下端面加上加工余量；中孔按照毛坯的外曲面设计为从下向上逐渐缩小为向内弯曲的内曲面。上述两项设计的横截面面积从下往上逐渐增加或保持一致。
铸型设计：根据轧辊毛坯设计的外曲面和中孔曲面形状以及所需加工余量进行铸型设计，铸型设计为铸造内型和铸造外型两部分；铸造内型设计为从下向上逐渐缩小为向内弯曲的内曲面中孔和下端面,铸造外型设计为毛坯外曲面从下向上逐渐缩小为向内弯曲的内曲面形状和上端面；
冶炼：冶炼所需单金属熔液；
浇铸：将铸造内型与铸造外型进行组装，将铸造外型从上而下套在铸造内型上形成毛坯型腔并且定位密封好，将冶炼好的单金属熔液浇入毛坯型腔中，待金属熔液凝固后，移开铸造外型，完成铸造异型轧辊的浇铸过程；
加工:对铸造完成的异形轧辊毛坯进行常规的加工及热处理工艺。
本发明可应用于焊接钢管轧机，冷弯型钢轧机，钢管矫直机，热轧无缝 钢管的定径机以及减径机等设备上。
采用本发明的双液双外型铸造方法所制备的复合铸造异型轧辊，以及采用本发明的单金属材料制备的铸造异型轧辊，获得了具有耐磨、耐冲击、耐激冷激热的辊身工作层，并且获得高强度高韧性的芯部。满足了焊接钢管以及冷弯型钢轧机等设备所用轧辊的服役条件要求，同时又使轧辊具有较长的使用寿命，降低了轧辊的制造成本，提高了焊接钢管以及冷弯型钢等产品生产的经济效益。
附图说明
图1是钢管矫直机轧辊的结构示意图；两端直径大、中间直径小并有中孔的异型轧辊结构示意图；
图2是钢管及冷弯型钢轧机轧辊，两端直径大、中间直径小并有中孔的异型轧辊结构示意图；
图3是轧辊铸型毛坯设计剖面示意图；图中，3-1为内层，3-2为外层，3-3为虚线示意的实际需要成品，3-4为内外层分界曲面；
图4是轧辊铸型中的铸造内型与内层的铸造外型进行组装的剖面示意图；图中，4-1为内层的铸造外型，4-2为铸造内型，4-3为内层型腔，4-4为密封装置，4-5为铸型定位装置。
图5是轧辊铸型中的内层与外层的铸造外型的组装剖面示意图；图中，5-1为外层的铸造外型，5-2为内外层分界曲面，5-3为外层型腔，5-4为密封装置，5-5为铸型定位装置，3-1为已浇铸的内层，4-2为铸造内型。
图6是单金属轧辊铸型中的铸造内型与铸造外型进行组装的剖面示意图；图中，6-1为铸造外型，6-2为铸造内型，6-3为毛坯型腔，6-4为密封装置，6-5为铸型定位装置。
具体实施方式
以下参照本发明的设计思想，示例性实施例并结合附图对本发明作如下详细说明。
本发明所涉及的异型轧辊均属于两端直径大、中间直径小的曲面类异型轧辊。这类异型轧辊的结构属辊与轴分离型，即都有中孔，在中孔内装上轴后安装到机架上。由于异型轧辊在钢管及冷弯型钢等钢管生产设备中需要承 受巨大压应力下的摩擦和冲击，以及高温轧材和冷却水的激冷激热作用，工作环境非常恶劣。同时在使用中还要经过多次的车磨修复。因此，要求轧辊具有足够厚的工作层来满足恶劣工况的特殊要求。即在节约材料和加工成本的情况下，设计出符合两端直径大、中间直径小的曲面类异型轧辊质量要求的铸造方法。此类异型轧辊还要求具有足够厚的工作层和高强度、高韧性的芯部相结合。理想状态下的异形轧辊应是由满足两种不同要求的双金属复合结构。由此，本发明为异型轧辊复合结构的制备提供了一种简单实用又能够保证质量的双液双外型铸造方法。同时，也为单金属材料铸造异型轧辊提供了保证质量的异型轧辊铸造方法。
本发明的铸造成型方法比锻造成型方法更能近似于成品，而且比锻造成型方法能添加更多的合金元素，提高了轧辊的各项技术性能。由于采用铸造方法能够大量的节材节能，并且提高了钢管生产用轧辊的使用寿命，使铸造成型方法越来越能满足钢管行业生产的需求，从而进一步推动了铸造行业的技术进步。
参照图1到图6，本发明的设计思想通过以下几种技术方案的具体实施得以体现。
本发明的一种技术方案为复合铸造异型轧辊，该轧辊的辊身是为两端直径大，中间直径小的曲面形状，该曲面形状由内层和外层两部分复合铸造结合而成，所述内层和外层的复合结合层是从下向上逐渐缩小为向内弯曲的曲面形状；沿轧辊的中轴线上具有一中孔，以在装轴时使用。
本发明的复合结构铸造异型轧辊采用双液双外型铸造方法及步骤来实现。
参照图3，在设计时，根据异型轧辊辊身两端直径大，中间直径小的曲面形状，将轧辊的毛坯外曲面及上下端面均按照异型轧辊成品的外曲面和上下端面加上加工余量进行设计，中孔按照毛坯的外曲面设计成向内弯曲的内曲面,即中孔从下向上逐渐缩小，从而使整个毛坯的横截面面积从下往上基本呈逐渐增加或基本保持一致的形态，使其在铸造时形成顺序凝固而不会造成铸造缺陷，解决了常规铸造方法容易形成铸造缺陷的问题。
设计时还依据具体工况对轧辊工作层厚度的要求，将毛坯设计成外层工作层和内层两部分，使内层3-1和外层3-2两部分的复合结合层呈从下向上逐渐缩小为向内弯曲的内曲面状态；内外层设计分界曲面3-4直径从下到上 逐渐减小、圆滑过度，以保证脱模顺畅。毛坯外层工作层的厚度在预留加工余量的基础上可以再加5mm～20mm，以充分保证重车时的修复量。为保证内外层冶金结合的质量，设计时使毛坯外层工作层与内层的重量比≥1.2：1。毛坯设计中的内外层分界曲面3-4在铸造熔融为一体后消失，形成外层和内层两部分两种金属互熔的复合结合层。图3中虚线3-3示意的是实际需要的轧辊成品，轧辊成品的中孔加工后为圆柱中孔。
参照图4和图5，根据轧辊毛坯设计的外曲面和中孔曲面形状以及所需加工余量进行铸型设计,铸型设计为铸造内型和铸造外型两部分；铸造内型4-2设计为从下向上逐渐缩小为向内弯曲的内曲面中孔和下端面，铸造外型设计为内层的铸造外型和外层的铸造外型两个外型部分，内层的铸造外型4-1为设计分界曲面和上端面，外层的铸造外型5-1为毛坯外曲面和上端面；组装时铸造外型从上而下套在铸造内型上，内层的铸造外型4-1与铸造内型4-2组装后形成毛坯内层型腔4-3，外层的铸造外型5-1与已经浇铸凝固的内层3-1及铸造内型4-2组装后形成毛坯外层型腔5-3，已凝固的内层3-1的边界曲面形成了内外层分界曲面5-2，从而形成了整个毛坯铸型。
在冶炼复合铸造异型轧辊时，同时分别冶炼内层和外层所需的金属熔液。冶炼所采用的复合材料组合设计为两种，分别铸造不同材料的产品。一种为高铬铸铁外层和铸钢内层复合材料；另一种为合金球铁外层和球铁内层复合材料。这两种复合材料可使内层和外层的铸造收缩率相同或相近，使内层和外层的凝固结合率一致。
浇铸时，先将铸造内型4-2与内层的铸造外型4-1进行组装，将内层的铸造外型4-1从上而下套在铸造内型4-2上形成毛坯内层型腔4-3，通过4-4的密封装置和4-5的铸型定位装置将其密封好，将冶炼好的内层金属熔液浇入毛坯内层型腔4-3中,待内层金属熔液凝固后，在金属凝固温度保持在850℃～950℃时将内层的铸造外型4-1移开，迅速或快速装上外层的铸造外型5-1，使其与已经浇铸凝固的内层3-1及铸造内型4-2形成毛坯外层型腔5-3，并通过5-4和5-5将其定位密封好，将冶炼好的外层金属熔液浇入毛坯外层型腔5-3中，待外层金属熔液凝固后，将外层的铸造外型5-1移开，即完成异型轧辊的浇铸过程。由于是在内层金属熔液凝固后仍处于850℃～950℃状态时浇入的外层金属熔液，因此形成外层和内层两部分两种金属互熔的复合结合层。铸造砂型内设置有测温器，内层金属凝固温度可由测温器获 得，单重小于500kg的铸件也可以通过检测冒口内金属液的温度进行判断。由于设计的内外层横截面面积从下往上基本呈逐渐增加或基本保持一致的形态，因此，金属熔液实现了顺序凝固，从而获得了理想的双金属复合铸造轧辊毛坯。
本发明还可以将轧辊多次重车后剩余比例很小的轧辊改为生产单金属轧辊毛坯。即将铸造内型与外层的铸造外型组装，只需冶炼和浇铸外层金属熔液，同样可实现顺序凝固，获得所需理想的轧辊毛坯。同理，还可以将轧辊单重较小，或工作层厚度要求大的轧辊改为生产单金属轧辊毛坯。从而简化了生产工艺，保证了铸坯质量。
参照图6，本发明的另一种技术方案就提供了一种单金属材料铸造异型轧辊。铸造异型轧辊同样为两端直径大，中间直径小的曲面形状,沿轧辊的中轴线具有一中孔，其采用以下制备方法来实现：
毛坯设计：根据单金属材料轧辊辊身两端直径大，中间直径小的曲面形状，将毛坯的外曲面和上下端面按照成品的外曲面从下向上逐渐缩小为向内弯曲的内曲面状态，上下端面加上加工余量，中孔按照毛坯的外曲面设计为从下向上逐渐缩小为向内弯曲的内曲面。上述两项设计的横截面面积从下往上逐渐增加或保持一致。
单金属材料的铸型设计和浇铸：根据轧辊毛坯设计的外曲面和中孔曲面形状以及所需加工余量进行铸型设计，铸型设计为铸造内型6-2和铸造外型6-1两部分；铸造内型6-2设计为从下向上逐渐缩小为向内弯曲的内曲面中孔和下端面,铸造外型6-1设计为毛坯外曲面从下向上逐渐缩小为向内弯曲的内曲面形状和上端面。将冶炼好的单金属熔液浇入由铸造外型6-1和铸造内型6-2组装，并且采用铸型定位装置6-5和密封装置6-4定位密封所形成的毛坯型腔6-3中，金属熔液凝固后即完成单金属铸造异型轧辊的浇铸过程。本发明的单金属材料铸造异型轧辊由于毛坯和中孔的横截面面积从下往上逐渐增加或保持一致，在铸造时很好的形成了顺序凝固，从而提高了轧辊辊身两端直径大，中间直径小的曲面形状的铸造质量，减少了铸造缺陷。
在铸造完成后，对复合铸造异形轧辊及铸造异型轧辊的铸造毛坯进行常规的加工工艺，即退火，粗加工，相适应的热处理和精加工，获得成品轧辊。在采用合金球铁材料时进行了等温淬火处理。
为增加铸型外型的强度，在铸型外型的铁制砂箱内壁上可以设置多个凸 出铁件，以增加砂箱与砂型的连接强度。还可以在外砂型内设置钢骨架以增加砂型的强度。为提高凝固速度，可以在砂型内掺入石墨粉粒或掺入镁砂，或在涂料中加入少量碲粉。
本发明的复合铸造异形轧辊采用的一种高铬铸铁外层和铸钢内层复合材料的优点在于，高铬铸铁具有良好的耐磨，耐冲击，耐激冷激热性能和良好的淬透性,铸钢具有高强度和高韧性,且二者的铸造收缩率相同或相近，可以使复合铸造的内外层很好的结合。其复合材料的具体组成设计按质量百分比计如下：
高铬铸铁外层：C：2.0％～2.6％，Si：0.2％～0.5％，Mn：0.6％～1.0％，Cr：11.0％～18.0％，Ni：0.5％～1.5％，Mo：0.5％～1.5％，W：0.5％～1.5％，Zr：0.1％～0.3％，Nb：0.05％～0.15％，Ti：0.05％～0.15％，RE：0.05％～0.15％，P：≤0.030％，S：≤0.025％，其余为Fe和不可避免的杂质。其中：Mo+W+Zr的含量按质量百分比计为大于等于1.2％且小于等于2.2％，Nb+Ti+RE的含量按质量百分比计为大于等于0.10％且小于等于0.40％，铸钢内层为铸造碳钢或低合金铸钢。
其中，C和Cr是高铬材料中最基本且最重要的合金元素。其含量的多少决定碳化物的数量，M7C3型碳化物与总碳化物的相对数量、硬度和韧性，以及材料的淬透性等。Mo元素在高铬材料各相中约50％进入Mo2C中，约25％进入M7C3型碳化物中，它可有效的提高材料的硬度和耐磨性。另外约有23％左右溶入基体，明显的提高了材料的淬透性。W原子和C原子的结合力大，提高了马氏体高温分解的稳定性，从而提高其红硬性。高温淬火时部分W碳化物溶入基体中，提高材料的淬透性。Ni元素强化了基体并改善了材料的综合性能，可提高淬透性。Zr的加入可以有效的提高材料的强度、硬度及红硬性。Ti能细化其共晶组织，形成稳定细小的TiC晶核。加入Nb可在基体中析出高硬度(2000HV)、高熔点、形状规则粒度小、均匀弥散分布的硬质相Nb(CN)质点，可有效地控制合金的凝固偏析，提高其综合性能，并起到节约Ni或Cr的作用。
铸钢内层成分根据具体的高铬铸铁成分，设计选用常规工程用铸造碳钢或低合金铸钢即可。高铬铸铁外层和铸钢内层复合材料所制备的异型轧辊主要用于焊管轧机，冷弯型钢轧机，钢管矫直机等设备上。
本发明采用的另一种复合材料为合金球铁外层和球铁内层。经过等温淬 火的合金球铁具有良好的耐磨，耐冲击，耐激冷激热性能和良好的淬透性。球铁具有高强度和高韧性，且二者的铸造收缩率相同或相近。其具体成分设计按质量百分比计如下：
合金球铁外层的组成为：C：3.0％～3.8％，Si：1.4％～1.8％，Mn：≤0.35％，Ni：≤2.5％，Cu：0.4％～1.0％，Mo：0.3％～1.0％，Cr：0.1％～0.3％，B：≤0.08％，Mg：0.04％～0.10％，Bi：0.0004％～0.0005％，Sb：0.0002％～0.0003％，P：≤0.04％，S：≤0.02％，其余为Fe和不可避免的杂质。其中：Ni+Cu的含量按质量百分比计为大于等于0.4％且小于等于2.5％，Cr+B的含量按质量百分比计为大于等于0.05％且小于等于0.25％；球铁内层的组成为：C：3.0％～3.8％，Si：2.2～2.7％，Mn：≤0.35％，Cu：0.4％～0.6％，Mg：0.04％～0.10％，P：≤0.04％，S：≤0.02％，其余为Fe和不可避免的杂质。其中，
在合金球墨铸铁中C是石墨化形成元素，C含量增高时，一方面阻碍渗碳体的析出，另一方面由于形成石墨核心的数目增多，可以细化石墨，提高石墨球的圆整度。但含C量过高容易形成石墨漂浮，C含量过低收缩倾向加大。因此，C含量选择为3.0％～3.8％较适宜。Si不仅能提高共析的转变温度，而且加宽了共析转变的温度范围，缩短了珠光体和贝氏体的孕育期。贝氏体球铁的性能随含硅量的增加而提高，含硅量增加可使石墨球径更为细小，而且硅能促进贝氏体转变，形成细针状贝氏体，从而提高针状组织的综合性能。但含硅量过高时，将促使形成铁素体，因此根据轧辊具体工况Si在1.4％～1.8％之间选取。而Mn是反石墨化元素，在合金球铁中与硫、氧化合形成MnS、MnO，因此Mn的主要作用是消除铁水中的硫和氧的有害作用。另一方面Mn是很容易偏析的元素，在不完全等温淬火的状态下，在共晶团晶界上将出现马氏体与残余奥氏体的混合组织，这种组织大大恶化了球铁的塑性。实践证明，少量的Mn有利于稳定和细化球光体，因此设定Mn为≤0.35％。P形成区域偏析的倾向很大，特别是厚大球墨铸铁件尤为显著。生产实践证实，一般P含量达到0.1％时，就会出现2％～3％的磷共晶，由于它的熔点低，凝固时被生长着的共晶团推移至周界最后凝固，所以磷共晶最终出现在共晶团晶界上，呈多角形硬脆磷共晶容易造成应力集中，从而降低材料的强度、塑性和韧性。因此设定P为≤0.04％。S是反石墨化元素，S高必然消耗较多的球化剂，因为球化元素都是强脱硫剂，加入后首先脱硫，然后才起球化作用。实践证明当含S量较高时即使加入镁、钙、锆和稀土元素，也不可能获得较 好的球化效果，从而导致性能下降。球铁中S含量应尽可能低，因此设定S为≤0.02％。Cr是最强烈的碳化物形成元素之一，碳化物的数量随Cr含量的提高而增加，从而使硬度上升，硬层深度加深，从而使耐磨性相应提高，这一现象，在同时加入镍和钼等元素进行多元合金化时，显的尤为突出。但Cr也是反石墨化元素，过高的Cr含量影响球化的整体性能，设定Cr在0.1％～0.3％之间较适宜。B形成高硬度的硼碳化物，可以显著提高合金球铁的耐磨性，但B也是反石墨化元素，根据实验结果B设定为≤0.08％。综合考虑Cr、B的作用及实验结果，设定Cr+B的含量按质量百分比计为大于等于0.05％且小于等于0.25％。Ni是扩大γ相区、形成和稳定奥氏体的主要合金元素。Ni不与碳形成碳化物，而是固溶于铁中，起稳定和细化珠光体组织的作用。实践证明Ni在增加大断面球铁中珠光体的含量、提高芯部抗拉强度方面都很有效果。在实际应用中，Ni与其它合金元素联合加入可获得比单独加Ni时的更佳效果。当Ni含量较高时，能稳定获得贝氏体，同时可使贝氏体细化，显著提高针状球铁组织的塑性和韧性。但Ni属稀贵金属，过高的含Ni量使成本大幅度增加，而使得市场难以接受，应根据不同轧辊的具体服役条件进行具体确定，故设定Ni为≤2.5。Cu在共晶转变中促进石墨化，其石墨化能力约为硅的30％，可降低奥氏体转变的临界温度，促进珠光体形成，对减少或消除游离渗碳体的形成有利，大大降低铸件薄壁处的白口化倾向，使球墨铸铁的韧性提高，同时可强化和细化珠光体和珠光体中的铁素体，从而提高铸件的硬度和强度。Cu与Mo和Mn联合应用时，对提高淬透性的效果更好。但过高的Cu含量会增加材料在热状态工作时产生脆裂的倾向，因此，Cu设定在0.4％～1.0％之间。综合考虑Ni、Cu的作用及实验结果，设定Ni+Cu的含量按质量百分比计为大于等于0.4％且小于等于2.5％。Mo是强有力的珠光体形成剂，对合金球铁的基本组织有很重要的影响。当铸铁中的Mo含量达到0.5％以上时，基体组织则全部转变为珠光体。加大Mo含量后，合金球铁的奥氏体分解受到抑制，形成针状贝氏体组织。Mo也属稀贵金属，过高的Mo含量使成本大幅度增加，而使得市场难以接受，应根据不同轧辊的具体服役条件进行具体确定，故设定Mo为0.3％～1.0％。Bi和Sb的微量加入可有效提高球化质量，尤其对单重较大的轧辊更为重要，可明显提高石墨球化率，改善石墨球的圆整度。
合金球铁外层和球铁内层复合材料所生产的异型轧辊主要用于热轧无缝 钢管的定径机以及减径机等设备上。
本发明制备的钢管及冷弯型钢生产用异型轧辊，采用了简单实用的双金属双外型铸造方法，利用轧辊的中孔将轧辊毛坯改变为利于铸造顺序凝固的结构，采用双外型铸造实现了双金属复合铸造。该方法简便易行效果良好，使异型轧辊同时具备耐磨，耐冲击，耐激冷激热的足够厚的工作层和高强度、高韧性的芯部，充分满足了使用需求。由于芯部的低合金化，不但节约了Cr、Ni、Mo、W等合金元素，而且增加了芯部的机械加工性能。异型轧辊的工作层选用了系列的高铬铸铁及合金球铁，满足了钢管及冷弯型钢轧机生产中对于各种不同服役条件的要求。同理，本发明的单金属材料铸造异型轧辊由于设计合理，在铸造时形成了很好的顺序凝固，减少了铸造缺陷，提高了铸造质量，满足了轧机生产对轧辊的各项性能要求。
本发明设计制备的工作层材料为高铬铸铁的钢管矫直辊、焊管及冷弯型钢轧辊，使用性能达到锻造D2(X155CrVMo12-1、SKD11)冷作模具钢和锻造H13(X40CrMoV5-1、SKD61)热作模具钢同类轧辊的性能指标。而材料利用率比锻造提高30％以上，达到了节能节材的良好效果。
以下结合实施例对本发明作进一步的详细说明。
参照附图1-6，以下各实施例在轧辊工作层的铸造外型中均匀设置有3至4个金属骨架，以增加砂箱与砂型的连接强度；在铸型中加入了5％～10％的石墨粉粒，在涂料中加入了常识的些许碲粉，以用来提高铸型毛坯的凝固速度。在异形轧辊毛坯外层厚度的加工余量上又增加了5mm～20mm，毛坯外层工作层的重量与内层的重量比≥1.2：1。在采用合金球铁材质时进行了常规的等温淬火热处理。
实施例1
参照附图1、3、4和5，本实施例为制造Φ720无缝钢管机组热处理线矫直机轧辊，每套6件，采用高铬铸铁外层和铸钢内层复合材料。比较例之一的现有锻造9Cr2MoV辊坯为自由锻的圆柱体，重量约为8948kg，使用寿命为1年。比较例之二的全仿形加工余量设计毛坯重量约为4681kg。
本实施例成品(图3)尺寸为：上、下端最大直径为Φ994mm、中间最小直径为Φ880mm、内孔为Φ480mm辊身高为1100mm，重量为4060kg/件。
本实施例毛坯设计(图3)的尺寸为：外园曲面按近似成品曲面设计上端为Φ1034mm、中间最小为Φ910mm、下端为Φ1013mm，中孔下端为 Φ471mm、向上逐渐缩小至上端为Φ344mm，设计分界曲面下端为Φ774mm、严格遵循直径从下到上逐渐减小圆滑过渡的曲面向上逐渐缩小至上端为Φ665mm，设计外层重量为2880kg、内层重量为2235kg。
根据上述尺寸制备出双外型铸型，即制备出铸造内型4-2，内层的铸造外型4-1(图4)和外层的铸造外型5-1(图5)。参照附图4，先将铸造内型4-2与内层的铸造外型4-1进行组装并定位密封好，使内层的铸造外型4-1与铸造内型4-2组装后形成毛坯内层型腔4-3；采用2台电炉同时冶炼高铬铸铁外层材料和铸钢内层材料，将冶炼好的铸钢内层熔液浇入毛坯内层型腔4-3中，待设置在铸型内的测温器显示为850℃时，将内层的铸造外型4-1移开，迅速安装上外层的铸造外型5-1，参照图5，再将冶炼好的外层高铬铸铁熔液浇入毛坯外层型腔5-3中，凝固后完成异型轧辊的整个浇铸过程。由于内外层横截面面积设计从下往上是逐渐增加的，因此，实现了顺序凝固，从而获得了100％合格的双金属复合铸造矫直机轧辊毛坯。获得的复合轧辊毛坯重为5115kg/件，为锻坯的57.1％，材料利用率提高42.8％；为全仿形加工余量设计毛坯重量的109％。不但保证了100％合格率。同时铸钢内层节约了大量的Cr、Ni、Mo、Zr等金属，降低了生产成本。
对铸造完成的异型轧辊毛坯进行常规的退火、粗加工、热处理和精加工，获得成品轧辊。经检测，外层的化学成分按质量百分比计为：C：2.12％，Si：0.40％，Mn：0.78％，Cr：16.10％，Ni：1.15％，Mo：1.30％，W：0.5，Zr：0.30％，Nb：0.10％，Ti：0.08％，RE：0.05％，P：0.023％，S：0.017％,其余为Fe和不可避免的杂质。
经检测和装机试用，轧辊工作面硬度为56.5HRC～57.6HRC，使用寿命可提高至2年以上。本实施例轧制相同钢管与9Cr2MoV锻钢轧辊使用效果对比见表1。
表1矫直辊耐磨性能对比
轧辊材质、成型方法 轧辊半径方向磨损1mm轧制钢管支数
9Cr2MoV锻钢辊 0.48万支
本发明铸造异型轧辊 1.07万支
从表1的矫直辊耐磨性能对比可看出，本发明的铸造异型轧辊与比较例之一的现有锻造9Cr2MoV轧辊对比，在轧辊半径方向磨损1mm矫直量的相同情况下，轧制量是其两倍以上。寿命也提高了一倍。同时，本实施例的成 品轧辊重量为4060kg/件，而比较例之一的轧辊重量约为8948kg，是本发明的一倍多；而比较例之二的轧辊重量为4681kg，也比本实施例重621kg。从而说明本发明不但使用寿命长，而且节省大量材料。
实施例2
参照附图1、3、4、5，本实施例为制造Φ250无缝钢管机组热处理线矫直机轧辊，每套6件，采用高铬铸铁外层和铸钢内层复合材料。比较例之一的现有锻造X155CrVMo12-1轧辊辊坯为自由锻圆柱体，重量约为1530kg。比较例之二的全仿形加加工余量设计毛坯重量约为990kg。
本实施例成品尺寸为：上、下端最大直径为Φ572mm、中间最小直径为Φ480mm、内孔为Φ240mm辊身高为660mm，重量为806kg/件。
本实施例毛坯(参照图3)尺寸设计为：外园曲面按近似成品曲面设计上端为Φ612mm、中间最小为Φ510mm、下端为Φ592mm，中孔下端为Φ235mm、向上逐渐缩小至上端为Φ148mm，设计分界曲面下端为Φ436mm、严格遵循直径从下到上逐渐减小圆滑过渡的曲面向上逐渐缩小至上端为Φ378mm，设计外层重量为614kg、内层重量为486kg。
根据上述尺寸制备出铸造内型4-2，内层的铸造外型4-1(图4)与外层的铸造外型5-1(图5)。参照附图4，先将铸造内型4-2与内层的铸造外型4-1进行组装并定位密封好，使内层的铸造外型4-1与铸造内型4-2组装后形成毛坯内层型腔4-3(图4)；采用2台电炉同时冶炼高铬铸铁外层材料和铸钢内层材料。将冶炼好的铸钢内层熔液浇入毛坯内层型腔4-3(图4)中，待设置在铸型内的测温器显示为950℃时，将内层的铸造外型4-1(图4)移开，迅速安装上外层的铸造外型5-1(图5)，再将冶炼好的外层高铬铸铁熔液浇入毛坯外层型腔5-3(图5)中，完成矫直机异型轧辊的浇铸过程。本实施例的内外层横截面设计合理，因此，实现了顺序凝固，获得了合格的复合铸造矫直机轧辊毛坯。该轧辊毛坯重量为1100kg/件，为锻坯的71.9％，材料利用率提高28.1％；为全仿形加工余量设计毛坯重量的111％，但保证了100％合格率。内层铸钢节约了大量的合金材料，降低了生产成本。
对异型轧辊毛坯进行常规的加工工艺，获得成品轧辊。轧辊外层的化学成分按质量百分比计为：C：2.20％，Si：0.38％，Mn：0.68％，Cr：17.10％，Ni：1.25％，Mo：1.00％，W：1.00％，Zr：0.20％，Nb：0.15％，Ti：0.10％，RE：0.10％，P：0.023％，S：0.017％，其余为Fe和不可避免的杂质。
轧辊工作面硬度56.8HRC～57.4HRC。经装机试用，本实施例轧制相同钢管与X155CrVMo12-1锻钢轧辊相比，使用效果好于锻钢轧辊。性能对比见表2。
表2矫直辊耐磨性能对比
轧辊材质、成型方法 轧辊半径方向磨损1mm轧制钢管吨数
X155CrVMo12-1锻钢辊 1.0万吨
本发明铸造异型轧辊 1.2万吨
从表2的矫直辊耐磨性能对比可看出，本发明的铸造异型轧辊与比较例之一的现有锻造X155CrVMo12-1轧辊对比，在轧辊半径方向磨损1mm矫直量的相同情况下，轧制量提高了0.2万吨。同时，本实施例的成品轧辊重量为806kg/件，而比较例之一的轧辊重量约为1530kg，几乎是本发明的一倍；而比较例之二的轧辊重量为990kg，也比本实施例多出近200kg。说明本发明节省了材料，生产效率高。
实施例3
参照附图2、3、4、5，本实施例为Φ406焊接钢管精成型轧辊，每套2件，采用高铬铸铁外层和铸钢内层复合材料。现有技术为锻造X155CrVMo12-1轧辊，锻造辊坯为自由锻的圆柱体，重量约为3180kg。
本实施例成品尺寸为：上、下端最大直径为Φ926mm、中间最小直径为Φ720mm、内孔为Φ340mm辊身高为530mm，重量为1657kg/件。
本实施例外园曲面按近似成品曲面设计上端为Φ966mm、中间最小为Φ750mm、下端为Φ946mm，中孔下端为Φ334mm、向上逐渐缩小至上端为Φ255mm，设计分界曲面下端为Φ644mm、严格遵循直径从下到上逐渐减小圆滑过渡的曲面向上逐渐缩小至上端为Φ598mm，设计外层重量1262kg、内层重量909kg。
本实施例根据上述尺寸制造铸造内型4-2(图4)，内层的铸造外型4-1(图4)和外层的铸造外型5-1(图5)。参照图4，将铸造内型4-2与内层的铸造外型4-1进行组装并定位密封好，组装后形成毛坯内层型腔4-3(图4)。同时冶炼高铬铸铁和铸钢材料。将冶炼好的铸钢熔液浇入毛坯内层型腔4-3中，待设置在铸型内的测温器显示为900℃时，将内层的铸造外型4-1移开，迅速安装上外层的铸造外型5-1，再将冶炼好的外层高铬铸铁熔液浇入毛坯外层型腔5-3(图5)中，完成异型轧辊的浇铸过程。本实施例在浇铸过程中， 完全实现了顺序凝固，获得了合格的轧辊毛坯。该轧辊毛坯重量为2171kg/件，为锻造辊坯的68.3％，材料利用率提高31.7％；为全仿形加工余量设计毛坯重量的108％，但保证了100％合格率。由于内层铸钢节约了大量的合金材料，使生产成本大为降低。
对复合铸造异型轧辊毛坯进行加工，热处理，获得成品轧辊。轧辊外层的化学成分检测按质量百分比计为：C：2.59％，Si：0.21％，Mn：0.63％，Cr：17.90％，Ni：1.45％，Mo：1.40％，W：0.50％，Zr：0.15％，Nb：0.15％，Ti：0.05％，RE：0.10％，P：0.024％，S：0.013％，其余为Fe和不可避免的杂质。
经装机试用，轧辊工作面硬度为59.8HRC～60.4HRC，轧辊半径方向磨损1mm时轧制焊管15万吨，达到锻造X155CrVMo12-1轧辊水平。
实施例4
参照附图2、3、4、5，本实施例为Φ147焊接钢管精成型轧辊，每套2件，采用高铬铸铁外层和铸钢内层复合材料。现有原锻造X155CrVMo12-1辊坯为自由锻的圆柱体，重量约为510kg。
本实施例成品尺寸为：上、下端最大直径为Φ576mm、中间最小直径为Φ520mm、内孔为Φ280mm辊身高为210mm，重量为261kg/件。本实施例毛坯尺寸为：外园曲面按近似成品曲面设计上端为Φ595mm、中间最小为Φ540mm、下端为Φ595mm，中孔下端为Φ278mm、向上逐渐缩小至上端为Φ211mm，设计分界曲面下端为Φ436mm，直径从下到上逐渐减小圆滑过渡的曲面向上逐渐缩小至上端为Φ379mm，轧辊外层重量231kg、内层重量139kg。
本实施例根据上述尺寸制造铸造内型4-2(图4)，内层的铸造外型4-1(图4)，外层的铸造外型5-1(图5)。参照附图4，将铸造内型4-2与内层的铸造外型4-1进行组装并密封好，使内层的铸造外型4-1与铸造内型4-2组装后形成毛坯内层型腔4-3(图4)；同时冶炼高铬铸铁和铸钢材料,将冶炼好的铸钢熔液浇入毛坯内层型腔4-3中，待设置在铸型内的测温器显示为900℃时，将内层的铸造外型4-1移开，迅速安装上外层的铸造外型5-1，再将冶炼好的外层高铬铸铁熔液浇入毛坯外层型腔5-3(图5)中，完成异型轧辊的浇铸过程。本实施例在浇铸过程中，实现了顺序凝固，获得了合格的轧辊毛坯。该轧辊毛坯重量为370kg/件，为锻造辊坯的72.5％，材料利用率提高27.5％；为全仿形加工余量设计毛坯重量的104％，但质量大大优于全仿形 设计毛坯。内层铸钢则节约了大量的合金材料，使生产成本大为降低。
对轧辊毛坯进行退火、粗加工、热处理和精加工待工序，获得成品轧辊。轧辊外层的化学成分按质量百分比计为：C：2.60％，Si：0.49％，Mn：0.93％，Cr：11.20％，Ni：0.51％，Mo：1.0％，W：0.8％，Zr：0.30％，Nb：0.05％，Ti：0.15％，RE：0.05％，P：0.020％，S：0.014％，其余为Fe和不可避免的杂质。
经装机实际生产过程中，轧辊工作面硬度58.2HRC～61.1HRC，轧辊半径方向磨损1mm可轧制焊管10万吨，与锻造X155CrVMo12-1轧辊水平相当。
实施例5
参照附图2、3、4、5，本实施例为Φ340热轧无缝钢管定径机轧辊，采用合金球铁外层和球铁内层复合材料。现有轧辊为铸造Ni3Mo1球铁轧辊，热处理工艺为正火，实物解剖检测冲击韧性为30KJ/m2。
本实施例的成品尺寸为：上、下端最大直径为Φ641mm、中间最小直径为Φ534mm、内孔为Φ190mm辊身高为420mm，重量为660kg/件。本实施例毛坯外园曲面按近似成品曲面设计上端为Φ661mm、中间最小为Φ554mm、下端为Φ661mm，中孔下端为Φ193mm、向上逐渐缩小至上端为Φ134mm，设计分界曲面下端为Φ417mm、严格遵循直径从下到上逐渐减小圆滑过渡的原则，曲面向上逐渐缩小至上端为Φ358mm，轧辊外层重量540kg、内层重量313kg。
根据上述尺寸制造铸造内型4-2(图4)，内层的铸造外型4-1(图4)，外层的铸造外型5-1(图5)。参照附图4，将铸造内型4-2与内层的铸造外型4-1进行组装并密封好，形成毛坯内层型腔4-3(图4)；同时冶炼合金球铁和球铁。将冶炼好的球铁熔液浇入毛坯内层型腔4-3中，待设置在铸型内的测温器显示为920℃时，将内层的铸造外型4-1移开，迅速安装上外层的铸造外型5-1，再将冶炼好的外层合金球铁熔液浇入毛坯外层型腔5-3(图5)中，完成热轧无缝钢管定径机轧辊毛坯的浇铸过程。本实施例由于实现了顺序凝固，得到了合格的轧辊毛坯。该轧辊毛坯重量为853kg/件，为全仿形加工余量设计毛坯重量的108％，但质量大大优于全仿形设计毛坯。同时内层铸铁每个铸件可节约9kg的Ni、3kg的Mo，降低了材料成本。
完成后的轧辊毛坯经过退火、粗加工、等温淬火热处理和精加工，成品 轧辊外层工作层的化学成分按质量百分比计为：C：3.65％，Si：1.72％，Mn：0.30％，Ni：2.0％，Cu：0.4％，Mo：0.70％，Cr：0.10％，B：0.05％，Mg：0.06％，Bi：0.0004％，Sb：0.0002％，P：0.03％，S：0.015％，其余为Fe和不可避免的杂质。内层的化学成分按质量百分比计为：C：3.2％，Si：2.55％，Mn：0.34％，Cu：0.4％，Mg：0.06％，P：0.023％，S：0.017％，其余为Fe和不可避免的杂质。
等温淬火后轧辊的工作面硬度为66HS～68HS，实物解剖检测冲击韧性为100KJ/m2。经装机试用，轧辊半径方向磨损1mm，轧制钢管8000支，现有铸造Ni3Mo1球铁辊半径方向磨损1mm，可轧制相同钢管7000支。本实施例在相同条件下比现有铸造Ni3Mo1球铁辊提高了1000支钢管的轧制量。
实施例6
参照附图2、3、4、5，本实施例为Φ250热轧无缝钢管定径机轧辊，采用高铬铸铁外层和铸钢内层复合材料。现有为铸造Ni3Mo1球铁轧辊。
本实施例成品轧辊尺寸为：上、下端最大直径为Φ484mm、中间最小直径为Φ420mm、内孔为Φ160mm，辊身高为265mm，重量为241kg/件。本实施例毛坯的外园曲面按近似成品曲面，设计上端为Φ498mm、中间最小为Φ436mm、下端为Φ498mm，中孔下端为Φ168mm、向上逐渐缩小至上端Φ111mm，设计分界曲面下端为Φ322mm，直径从下到上逐渐减小圆滑过渡，曲面向上逐渐缩小至上端为Φ284mm；设计毛坯外层重量204kg、内层重量109kg。
根据上述尺寸制造铸造内型4-2(图4)，内层的铸造外型4-1(图4)，外层的铸造外型5-1(图5)。参照附图4，将铸造内型4-2与内层的铸造外型4-1进行组装并密封定位好，形成毛坯内层型腔4-3(图4)；同时冶炼高铬铸铁和铸钢。将冶炼好的铸钢熔液浇入毛坯内层型腔4-3中，待设置在铸型内的测温器显示为910℃时，将内层的铸造外型4-1移开，迅速安装上外层的铸造外型5-1，再将冶炼好的外层高铬铸铁熔液浇入毛坯外层型腔5-3(图5)中，完成热轧无缝钢管定径机轧辊毛坯的浇铸过程。本实施例轧辊毛坯重量为313kg/件，为全仿形加工余量设计毛坯重量的109％，但保证了100％合格率，质量优于全仿形设计毛坯。
加工完成后的成品轧辊经检测，轧辊外层的化学成分按质量百分比计为：C：2.10％，Si：0.21％，Mn：0.65％，Cr：18.00％，Ni：1.50％，Mo：0.50％， W：1.10％，Zr：0.30％，Nb：0.05％，Ti：0.05％，RE：0.10％，P：0.020％，S：0.014％，其余为Fe和不可避免的杂质。经检测，轧辊工作面硬度73HS～77HS。经装机使用，本实施例的轧辊轧制相同钢管从使用到修复期间与现有球铁轧辊寿命对比如表3。
表3本发眀轧辊与球铁轧辊寿命对比
轧辊材质、成型方法 从使用到修复间轧制钢管支数
进口球铁轧辊 6000
国产球铁轧辊 4000
本发明复合铸造轧辊 12000
表中本实施例的复合铸造异型轧辊的生产效果比前两种轧辊提高了两倍及两倍以上。
实施例7
参照附图2、3、4、5，本实施例为Φ720热轧无缝钢管四辊式定径机轧辊，该四辊式定径机为新上机组，是世界上最大的热轧无缝钢管定径机轧辊。属超厚大球墨铸铁件，无论铸造和热处理均有相当难度。采用合金球铁外层和球铁内层复合材料。
本实施例的成品尺寸为：上、下端最大直径为Φ1160mm、中间最小直径为Φ1108mm、内孔为Φ330mm辊身高为400mm，重量为2495kg/件。
本实施例的设计毛坯尺寸为：外园曲面按近似成品曲面设计上端为Φ1194mm，中间最小为Φ1141mm，下端为Φ1194mm，中孔下端为Φ366mm，向上逐渐缩小至上端为Φ277mm，设计分界曲面下端为Φ730mm，直径从下到上逐渐减小圆滑过渡的曲面向上逐渐缩小至上端为Φ676mm；设计外层重量为2060kg，内层重量为1090kg。
根据上述尺寸制造铸造内型4-2(图4)，内层的铸造外型4-1(图4)，外层的铸造外型5-1(图5)。参照附图4，将铸造内型4-2与内层的铸造外型4-1进行组装并密封好，形成毛坯内层型腔4-3(图4)；2台电炉同时冶炼合金球铁和球铁。将冶炼好的球铁熔液浇入毛坯内层型腔4-3中，待设置在铸型内的测温器显示为880℃时，将内层的铸造外型4-1移开，迅速装上外层的铸造外型5-1，再将冶炼好的外层合金球铁熔液浇入毛坯外层型腔5-3(图5)中，完成定径机轧辊毛坯的浇铸过程。获得的复合轧辊毛坯重为3150kg/件，与全仿形加工余量铸造毛坯设计重量基本相等，保证了100％合格率， 同时内层球铁每个铸件可节约33kg的Ni和11kg的Mo，节省了原材料，降低了生产成本。
对完成的定径机轧辊毛坯进行常规的退火、粗加工、等温淬火和精加工，获得成品轧辊。轧辊外层化学成分按质量百分比计为：C：3.80％，Si：1.41％，Mn：0.25％，Ni：2.05％，Cu：0.4％，Mo：1.00％，Cr：0.20％，B：0.03％，Mg：0.06％，Bi：0.0004％，Sb：0.0002％，P：0.03％，S：0.015％，其余为Fe和不可避免的杂质。内层的化学成分按质量百分比计为：C：3.75％，Si：2.20％，Mn：0.30％，Cu：0.50％，Mg：0.06％，P：0.023％，S：0.017％，其余为Fe和不可避免的杂质。
等温淬火后轧辊工作面硬度65HS～69HS。经装机试用，轧辊半径方向磨损1mm轧制钢管7000支，达到了设计要求。
实施例8
参照附图1和6，本实施例为Φ89无缝钢管单一金属材料矫直机轧辊，每套6件，采用高铬铸铁材料。现有锻造X155CrVMo12-1辊坯为自由锻的圆柱体，重量约为427kg。由于该辊在使用中需修复6次以上，每次修复量约为5mm，同时辊本身尺寸、重量均较小，故采用单一金属材料制造。
本实施例成品尺寸为：上、下端最大直径为Φ342mm、中间最小直径为Φ297mm、内孔为Φ165mm，辊身高为440mm，重量为172kg/件。本实施例毛坯尺寸为：外园曲面按近似成品曲面设计上端为Φ361mm、中间最小为Φ317mm、下端为Φ361mm，中孔下端为Φ157mm、直径从下到上逐渐减小为圆滑过渡的曲面，向上逐渐缩小至上端为Φ119mm。
本实施例根据上述尺寸制造铸造内型6-2(图6)，铸造外型6-1(图6)。参照附图6，将铸造外型6-1与铸造内型6-2进行组装并采用铸型定位装置6-5和密封装置6-4将两个铸型定位和密封好后，铸型形成毛坯型腔6-3(图6)。将冶炼好的高铬铸铁熔液浇入毛坯型腔6-3中，待毛坯型腔6-3中的金属溶液凝固后，将铸造外型6-1移开，完成异型轧辊的浇铸过程。
本实施例在浇铸过程中完整实现了顺序凝固，获得了质量合格的轧辊毛坯。该轧辊毛坯重量为256kg/件，为锻造辊坯的60％，材料利用率提高40％；节约了合金材料，降低了生产成本。
对轧辊毛坯进行退火、粗加工、热处理和精加工等工序，获得成品轧辊。轧辊辊身的化学成分按质量百分比计为：C：2.38％，Si：0.35％，Mn：0.91％， Cr：17.90％，Ni：1.2％，Mo：0.89％，W：1.1％，Zr：0.1％，Nb：0.015％，Ti：0.10％，RE：0.08％，P：0.030％，S：0.018％，其余为Fe和不可避免的杂质。
加工好的成品轧辊工作面硬度为58.2HRC～59.9HRC。经装机实际生产过程中，轧辊半径方向磨损1mm，轧制无缝钢管2.8万吨，为锻造X155CrVMo12-1轧辊的1.15倍。
本发明的上述实施例均已经过实际使用。其实际应用的效果和数据对比说明，采用本发明的两种铸造方法所制备的复合铸造异型轧辊和铸造异型轧辊，其使用性能均比现有轧辊有了很大提高。本发明具有高强度，高韧性和高耐磨性，以及良好的耐冲击性能。轧辊的使用寿命有很大的提高，进而降低了生产和维修成本，提高了生产效率。同时，本发明从毛坯和铸型设计到浇铸工艺均节约了大量的金属材料，也减少了加工成本，产生了良好的经济效益以及节能和节材效果。
本发明不限于上述实施例，在不脱离本发明设计思想的范围内，可以进行各种变形和修改，这些变化和修改均属于本发明的保护范围。

Claims (17)

  1. 一种复合铸造异型轧辊，其特征在于，所述复合铸造异型轧辊的辊身呈曲面形状，所述曲面形状由内层和外层两部分复合结合组成，所述内层和外层的复合结合层为曲面形状，沿轧辊的中轴线具有一中孔。
  2. 根据权利要求1所述的复合铸造异型轧辊，其中，所述曲面形状为，轧辊辊身两端直径大，中间直径小；所述复合结合层呈从下向上逐渐缩小为向内弯曲的曲面形状。
  3. 根据权利要求1所述的复合铸造异型轧辊，其中，所述异形轧辊采用两种复合材料铸造而成，高铬铸铁外层和铸钢内层；或者合金球铁外层和球铁内层。
  4. 根据权利要求3所述的复合铸造异型轧辊，其中，所述高铬铸铁外层和铸钢内层的复合材料组成按质量百分比计为：
    高铬铸铁为：C：2.0％～2.6％，Si：0.2％～0.5％，Mn：0.6％～1.0％，Cr：11.0％～18.0％，Ni：0.5％～1.5％，Mo：0.5％～1.5％，W：0.5％～1.5％，Zr：0.1％～0.3％，Nb：0.05％～0.15％，Ti：0.05％～0.15％，RE：0.05％～0.15％，P：≤0.030％，S：≤0.025％，其余为Fe和不可避免的杂质；铸钢为铸造碳钢或低合金铸钢。
  5. 根据权利要求4所述的复合铸造异型轧辊，其中，高铬铸铁外层中Mo+W+Zr的含量按质量百分比计为大于等于1.2％且小于等于2.2％，Nb+Ti+RE的含量按质量百分比计为大于等于0.10％且小于等于0.40％。
  6. 根据权利要求3所述的复合铸造异型轧辊，其中，所述合金球铁外层和球铁内层的复合材料组成按质量百分比计为：
    合金球铁为：C：3.0％～3.8％，Si：1.4％～1.8％，Mn：≤0.35％，Ni：≤2.5％，Cu：0.4％～1.0％，Mo：0.3％～1.0％，Cr：0.1％～0.3％，B：≤0.08％，Mg：0.04％～0.10％，Bi：0.0004％～0.0005％，Sb：0.0002％～0.0003％，P：≤0.04％，S：≤0.02％，其余为Fe和不可避免的杂质；
    球铁为：C：3.0％～3.8％，Si：2.2％～2.7％，Mn：≤0.35％，Cu：0.4％～0.6％，Mg：0.04％～0.10％，P：≤0.04％，S：≤0.02％，其余为Fe和不可避免的杂质。
  7. 根据权利要求6所述的复合铸造异型轧辊，其中，合金球铁中Ni+Cu的含量按质量百分比计为大于等于0.4％且小于等于2.5％，Cr+B的含量 按质量百分比计为大于等于0.05％且小于等于0.25％。
  8. 一种复合铸造异型轧辊的制备方法，其特征在于，所述复合铸造异形轧辊采用两种复合材料，所述制备方法采用双液双外型铸造方法，其步骤如下：
    毛坯设计：根据轧辊辊身两端直径大，中间直径小的曲面形状，将毛坯的外曲面和上下端面按照成品的外曲面和上下端面加上加工余量进行设计，中孔按照毛坯的外曲面设计为从下向上逐渐缩小为向内弯曲的内曲面；
    将毛坯设计为内层和外层两部分，内层和外层两部分的复合结合层呈从下向上逐渐缩小为向内弯曲的内曲面状态，内层和外层的横截面面积从下往上逐渐增加或保持一致，内外层设计分界曲面的直径从下到上逐渐减小且圆滑过度；
    铸型设计：根据轧辊毛坯设计的外曲面和中孔曲面形状以及所需加工余量进行铸型设计，铸型设计为铸造内型和铸造外型两部分，铸造内型设计为从下向上逐渐缩小为向内弯曲的内曲面中孔和下端面，铸造外型设计为内层的铸造外型和外层的铸造外型两个外型部分，内层的铸造外型为设计分界曲面和上端面，外层的铸造外型为毛坯外曲面和上端面；
    冶炼：同时分别冶炼内层和外层两种所需金属熔液；
    浇铸：先将铸造内型与内层的铸造外型进行组装，将内层的铸造外型从上而下套在铸造内型上形成毛坯内层型腔并密封好，将冶炼好的内层金属熔液浇入毛坯内层型腔中，待内层金属熔液凝固后，将内层的铸造外型移开，快速装上外层的铸造外型形成毛坯外层型腔并密封好，将冶炼好的外层金属熔液浇入毛坯外层型腔中，待外层金属熔液凝固后，移开外层的铸造外型，完成复合铸造异型轧辊的浇铸过程；
    加工：对铸造完成的异形轧辊毛坯进行常规的加工及热处理工艺。
  9. 根据权利要求6所述的复合铸造异型轧辊的制备方法，其中，所述异形轧辊毛坯外层厚度加上加工余量再加5mm～20mm；毛坯外层的重量与内层的重量比≥1.2：1。
  10. 根据权利要求8所述的复合铸造异型轧辊的制备方法，其中，在将内层的铸造外型移开时的金属凝固温度保持在850℃～950℃。
  11. 根据权利要求8所述的复合铸造异型轧辊的制备方法，其中，所述两种复合材料为：高铬铸铁外层和铸钢内层；或者合金球铁外层和球铁内层；在采用合金球铁时进行等温淬火热处理。
  12. 根据权利要求8所述的复合铸造异型轧辊的制备方法，其中，在外层的铸造外型中设有多个金属骨架，以增加砂箱与砂型的连接强度。
  13. 根据权利要求8所述的复合铸造异型轧辊的制备方法，其中，在铸型中加入适量的石墨粉粒或镁砂，以及在涂料中加入些许碲粉，以提高铸型的凝固速度。
  14. 一种铸造异型轧辊，其特征在于，所述铸造异型轧辊的辊身呈曲面形状，所述曲面形状为轧辊辊身的两端直径大，中间直径小，沿轧辊的中轴线具有一中孔。
  15. 一种铸造异型轧辊的制备方法，其特征在于，所述铸造异形轧辊采用单金属材料铸造，步骤如下：
    毛坯设计：根据轧辊辊身两端直径大，中间直径小的曲面形状，将毛坯的外曲面和上下端面按照成品的外曲面从下向上逐渐缩小为向内弯曲的内曲面状态，上下端面加上加工余量；中孔按照毛坯的外曲面设计为从下向上逐渐缩小为向内弯曲的内曲面；上述两项设计的横截面面积从下往上逐渐增加或保持一致；
    铸型设计：根据轧辊毛坯设计的外曲面和中孔曲面形状以及所需加工余量进行铸型设计，铸型设计为铸造内型和铸造外型两部分，铸造内型设计为从下向上逐渐缩小为向内弯曲的内曲面中孔和下端面，铸造外型设计为毛坯外曲面从下向上逐渐缩小为向内弯曲的内曲面形状和上端面；
    冶炼：冶炼所需单金属熔液；
    浇铸：将铸造内型与铸造外型进行组装，将铸造外型从上而下套在铸造内型上形成毛坯型腔并密封好，将冶炼好的单金属熔液浇入毛坯型腔中，待金属熔液凝固后，移开铸造外型，完成铸造异型轧辊的浇铸过程；
    加工：对铸造完成的异形轧辊毛坯进行常规的加工及热处理工艺。
  16. 根据权利要求11所述的铸造异型轧辊的制备方法，其中，在铸造外型中设有多个金属骨架，以增加砂箱与砂型的连接强度。
  17. 根据权利要求11所述的铸造异型轧辊的制备方法，其中，在铸型中加入适量的石墨粉粒或镁砂，以及在涂料中加入些许碲粉，以提高铸型的凝固速度。
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