US3659323A - A method of producing compound cast rolls - Google Patents

A method of producing compound cast rolls Download PDF

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Publication number
US3659323A
US3659323A US844038A US84403869A US3659323A US 3659323 A US3659323 A US 3659323A US 844038 A US844038 A US 844038A US 84403869 A US84403869 A US 84403869A US 3659323 A US3659323 A US 3659323A
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Prior art keywords
roll
partition member
shell
percent
weight
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US844038A
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English (en)
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Mikio Hachisu
Chikanori Saito
Osamu Sitamura
Yasuo Nambu
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Hitachi Ltd
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Hitachi Ltd
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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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49544—Roller making
    • Y10T29/4956—Fabricating and shaping roller work contacting surface element
    • Y10T29/49563—Fabricating and shaping roller work contacting surface element with coating or casting about a core
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/4998—Combined manufacture including applying or shaping of fluent material
    • Y10T29/49988—Metal casting
    • Y10T29/49989—Followed by cutting or removing material

Definitions

  • ABSTRACT A compound cast roll comprising a shell made of a steel having excellent rolling properties, an arbor having a body portion made of a steel or iron having high toughness and a cylindrical partition member interposed between said shell and said core, said three members being metallurgically connected together into an integral body and subjected to a heat treatment to impart desired properties to said shell and said core.
  • the present invention relates to compound cast rolls adapted for use inrolling milltacilities.
  • Rolling mill-rolls are mostlyproduced 'in the form or one bodyby pouring a moltenmetal. intoamold of a shape conforming to the shape of adesired roll. Further, the rolling mill rolls are required to have various properties which are variable depending upon the type of roll, but regardless of the type,
  • materials of which the rollingmill rolls aremade are desirably of such'a chemical composition which will afford these properties.
  • high alloycast steel maybe named.
  • cast steel because of poor castability of a 'highalloy steel material-,one body cast rolls tend to have inter- I As a materialwhich is satisfactory with respectto the 4
  • back up rolls which are particularly required to be resistive to wear and spalling, it is known to be essential to increase the hardness as high as possible but increasing the hardnessundergoes alimitation because if a high alloy steel is used to increase the hardness of a back up roll of one body'type, the casting and heat-treating operations are rendered difficult.
  • alloy steels consisting of 0.4 to 1.2 percent by weight of carbon, '1 .0 to 3.,0.percentby'weight of chromium, 0.3 vto'0.6 percent by weightof molybdenum, 2.0 percent-by weight or less; of nickel and the'remainder of iron, have been used for the production ofj back rolls. Because of such composition of the alloy; steels used. the product back up rolls had a hardness jot not higher than Rs 65 and were susceptible to wear and spalling.
  • slabbing mill. rolls and blooming mill rolls have commonly been produced by a method comprising casting a low alloy steel'consistinggenerally'of 0.6 to l.2 percent by weight of carbon, 0.4 to 2.0 percent by weight of chromium, 0.2 to 0.6
  • cast iron compound roll is usually produced by pouring a molten'metal into a casting mold ofashape conformingtofthe shellmade of a cast iron'containing a relatively large amount cast iron, and sleeve fitting rolls or sleeve rolls'which comprise a sleeve and an arbour mechanical I other, are presently available.
  • a shell-core type compound'roll has not been put in use in which the shall is made of a high alloyca'st steel and the core is made of plain-cast iron, plain cast steel m]; low alloy steel, however. This is because of the followingreason: Namely, a
  • the pouring temperature of the high alloy cast steel is so high that it is difficult to adjust the molten high alloy cast steel to a suitable pouringtemperature, and moreoverthe solidification speed of the high alloy cast steel is so high that it is ex-v tremely difficult to remove, the central steel to form a uniform shell.
  • a cast iron compound roll the shell of which is made of a cast iron containing a relativelylarge amount of alloy elements, is inferior to a compound roll whose shell is portion, of the molten made of high alloy cast steel in respect of toughness, and cannot be used in recent rolling mills which arerequired to be operable under severe rolling conditions.
  • the range of use of the cast iron compound roll is considerably limited.
  • high alloy steel as used in the description is general reference to those steels which'contain 0.2 to 2.6 percent by weight of carbon'and 3 percent by weight or more in total amount of alloy elements; the term "low alloy. steel to those steels in which the total amount of alloy elements is 3 percent by weight or smaller; theterrn plain steel to those I steels which contain alloy'elements in only such an amount as ,that of impurities; and the term plain cast iron to those cast irons which contain 3.010 3.6 percent by weight of carbon and no alloy element or 3 percent by weight or less alloy elements as required.
  • An object of the present invention is to provide a novel compound cast roll which comprises a shell and a body porly cornbined-with each tion of an arbor clearly separated from each other by a cylindrical partition member.
  • Another object of the invention is to provide a compound cast roll in which the shell is made of a high alloy cast steel.
  • Still another object of the invention is to provide a compound cast roll in which the shell and the body portion are rigidly combined with each other.
  • Still another object of the invention is to provide a compound cast roll in which the rolling characteristic of the roll is uniform substantially throughout the width of the shell.
  • a further object of the invention is to provide a compound cast roll in which the shell has properties suitable for rolling, such as resistances to fire crack, wear, spalling, surface roughening and breakage, while the arbor has high toughness.
  • An additional object of the invention is to provide a novel method of producing a compoundcast roll in which the shell is made of a high alloy cast steel.
  • the compound cast roll according to the present invention is composed of a steel shell having excellent rolling characteristics and a highly tough arbor.
  • the shell and the arbor are metallurgically bonded with each other through the intermediary of a cylindrical partition member, and said shell is formed such that the hardness thereof is not substantially reduced over a portion of its width from the surface of the shell at least to a portion adjacent the cylindrical partition member.
  • a preferable compound cast roll according to the present invention which comprises a shell of high alloy cast steel, is composed of a shell made of a high alloy cast steel which contains 0.2 to 2.6 percent by weight of carbon and 3 percent by weight or more in total amount of alloy elements, and a core made of a member selected from the group consisting of low alloy steel, plain cast iron and plain carbon steel, said shell and said core being metallurgically bonded-with each other through the intermediary of a cylindrical partition member andsaid shell being formed such that the hardness thereof is not substantially reduced over a portion of its width from the surface of the shell at least to a portion adjacent said cylindrical partition member.
  • the shell is made of high alloy cast steel and arbor of a member selected from the group consisting of low alloy steel, plain cast iron and plain carbon steel.
  • the partition member is preferably cylindrical in shape to uniformalize the thickness and rolling properties of the shell.
  • This cylindrical partition member serves to produce a metallurgical connection between the shell and the body portion of the arbor and to prevent migration of said shell and said arbor.
  • it In order for the partition member to serve such purposes, it must be capable of metallurgical connection with boththe shell and the body portion of the arbor.
  • the present inventors have found that the degree of metallurgical connection between the partition member and the shell and arbor depends upon the thickness, composition, properties and surface condition of the partition member.
  • the tensile strength of the partition member may be 30 kg./mm. or greater for said partition member to withstand a stress imposed thereon. Further, the tensile strength of the metallurgical connection must be 10 kg./mm. or greater in the radial direction of the roll.
  • the proportion of the cross sectional area of the partition member to that of the entire-roll is from 2 to 15 percent.
  • the melt-bonding property of the partition member is improved as the carbon content increases, but excessively high carbon content results in melting-away of the partition member, allowing inter-mixing of the shell and the core. Therefore, selection of the partition member must be made based on the pouring temperatures and the pouring times of both the shell and the arbor.
  • the surface condition carbon is coated or aluminum is applied to the surface of the partition member so as to prevent formation of an oxide film thereon. Occasionally, the surface of the partition member may be subjected to such a treatment as carbonization, nitrification or aluminization, which is effective to improve the bonding property of the partition member.
  • the hardness of the shell is not substantially reduced from the surface thereof to at least a portion adjacent the partitionmember.
  • Such feature is essential to obtain a stable rolling performance of the roll over an extended period.
  • the solidification of the shell can be attained adequately and the effect of heat treatment can be extended uniformly throughout the shell.
  • the thickness of the shell must be at least as large as the effective thickness of the roll, but in practice it is desirable that the thickness is 1.1 to 3 times the effective thickness of the roll, in consideration of the safety factor of the roll. Therefore, the partition wall is preferably located at a depth from the roll surface 1.1 to 3 times, particularly 1.2 to 2.5 times, the available thickness of the roll.
  • a high alloy cast steel of which said shell is formed must contain 0.2 to 2.6 percent by weight of carbon and 3 percent by weight or more in total of alloy elements. This is because, if the carbon content is smaller than 0.2 percent by weight, a desired strengthv cannot be obtained, whereas if the carbon content is larger than 2.6 percent by weight, the wear-resisting property of the shell is degraded to the level of the cast iron.
  • the alloy elements form carbides upon being compounded with carbon or are dissolved into the matrix to strengthen said matrix. They also improve the quenching effect and provide necessary properties to the shell.
  • Ni, Cr, Mo, V, Ti, W, Si, Mn, etc. are usually used and these elements are effectively combined with each other to afford desired properties to the shell. If the content of these elements is 3 percent or less in total, a satisfactory rolling properties of the roll cannot be obtained as has been experienced with the conventional one body roll, because the hardness of the shell cannot be made uniform throughout the thickness thereof, due to insufficient quenching effect. On the other hand, if the content of these elements is 2.5 percent or more, the castability of the steel is generally degraded unless the elements used are incorporated in the steel with particular care.
  • the present invention proposes to use, as a material of the shell, a cast steel based on C-Cr.
  • Cr is used in many tool steels as a carbide-forming element for promoting the quenching effect and, therefore, has sufficient properties as a roll material.
  • Cr By changing the amount of Cr in the range from 3 to 20 percent with respective to a carbon content of 0.2 to 2.6 percent, Cr can be applied to many rolls.
  • Cr is also one of economical elements. The more the contents of C and Cr are, the more the amount of carbide formed will be and thus a roll material of excellent wear-resistance can be obtained.
  • the toughness of the roll material is degraded on the other hand. For this reason, Ni, Mo, V, Ti, Mn, Si, W, etc. are incorporated in the steel as alloy elements, each in an amount of not more than 3 percent, whereby a roll material can be obtained which is tough and enables the quenching effect to be promoted and further has excellent rolling properties.
  • Ni and Mn serve to strengthen the matrix and promote the quenching effect
  • Mo, W and Si serve to improve the mechanical properties of the matrix at elevated temperatures and form carbides to improve the wear-resistance
  • V and Ti serve to produce a fine structure of the cast steel to increase the strength thereof.
  • the properties required for a roll are variable depending upon the type of the roll since the conditions in which the roll is used are variable. Accordingly, the chemical composition of a high alloy cast steel of which the shell is formed should be adjusted in accordance with the type of a desired roll, while refraining from making the material cost unduly high.
  • a high alloy cast steel is used for the formation of the shell which comprises 0.2 to 0.8 percent by weight of carbon, 3 to 6 percent by weight of chromium and substantially the same amounts of other elements as contained in the conventional roll.
  • a high alloy cast steel which comprises 0.8 to 2.0 percent by weight of carbon, 6 to 12 percent by weight of chromium and substantially the same amounts of other elements as contained in the conventional roll.
  • a high alloy cast steel which comprises 1.5 to 2.6 percent by weight of carbon, to 15 percent by weight of chromium and substantially the same amounts of other elements as contained in the conventional roll.
  • the partition member must be of such a material which is capable of producing a metallurgical connection between the shell and the arbor. Since the partition member is used essentially for the purpose of preventing the formation of internal shrinkages in the contacting surfaces of the shell and the body portion of the arbor, and simultaneously of preventing the excess migration of the shell-forming material and the arbor forming material, it may be required to be in a length equal to the length of the roll body.
  • the journals of a roll are usually made of the same material as the body portion but since they are rotatably supported by parts of a rolling mill in frictional engagement therewith, they are susceptible to wear.
  • the partition member may be made of a material more resistive to wear than the core material and the length of such partition member may be extended to a length equal to the overall length of the arbor, so that the journals of the roll may be covered with the partition member.
  • a portion of the partition member which is subjected to the heat of a shell-forming molten metal at first in the casting operation that is, a portion of the partition member located in the bottom of a casting mold, is not deformed or molten away during the casting operation.
  • the present inventors have found that it is advantageous from the standpoint of roll performance to reduce the wall thickness of the partition member from the bottom to top so as to produce a positive temperature gradience in the solidification of the shell-forming molten metal. In other words, it is necessary to change the wall thickness of the partition member progressively from one end to another.
  • the present inventors have found that when the partition member is disposed in the casting mold with the thicker wall end thereof located in the bottom of said mold, a portion of the partition member which is held in contact with the molten metal for the longest time during casting operation is thicker in wall thickness than the other portion, so that said portion of the partition member will not be molten and the solidification of the molten metal will take place with a positive temperature gradience.
  • a mechanical connection can be produced simultaneously with the metallurgical connection.
  • partition member sections may be arranged longitudinally and welded together.
  • assembly of such partition member sections may be facilitated by making either the outer or inner diameter thereof same.
  • the partition member must have a certain mechanical strength per se, to provide the connection between it, and the shell and the arbor, with a mechanical strength sufficient to withstand a stress applied thereto during rolling operation.
  • the material of which the partition member is fonned is preferably selected from the group consisting of plain carbon steel, low alloy steel and cast iron which have a tensile strength of about 30 kg./mm. or greater.
  • a high carbon steel excelling in wear resistance may be used for the formation of the partition member, and in this case, lowering of machinability becomes a problem. Such problem can be solved by employing the centrifugal casting method, however.
  • the compound cast roll according to the present invention is produced by setting a cylindrical partition member having a predetermined diameter in a casting mold, pouring a shell-forming molten metal of steel having excellent rolling properties into an annular space between the casting mold and the partition member and pouring a core-forming melt of steel or iron having high toughness into the hollow of the partition member.
  • FIG. 1 is a perspective view, partly in section, showing the appearance of a rolling mill roll according to the present invention
  • FIG. 2 is a photograph showing a cross-sectional view taken along the line 11-11 ofFIG. 1;
  • FIG. 3 is a microscopic photograph of the cross-section of FIG. 2, showing the structure at the border of the shell and the partition member;
  • FIG. 4 is a microscopic photograph, similar to FIG. 3, showing the structure at the border of the body portion and the partition member;
  • FIG. 5 is a perspective view showing in cross-section the construction of a mold used for practicing the present invention.
  • FIG. 6 is a transverse cross-sections view of a roll in which the partition member is extended over the journals thereof;
  • FIG. 7 is a diagram graphically showing the hardness distributions of a one body cast steel roll and a compound cast roll, relative to the distance from the roll surface;
  • FIG. 8 is a diagram graphically showing the forms of chromium carbides in relation to the amounts of chromium and carbon;
  • FIGS. 9 to 19 are cross-sectional views showing the partition members used in the present invention.
  • a compound cast roll for use as a back up roll having a diameter of 1,250 mm., a total length of 4,300 mm., a roll body length of 1,500 mm., a shell thickness of 200 mm. and a partition member thickness of 25 mm. was produced.
  • the shelland core-forming metals of the compositions shown in Table l were molten in an electric furnace, respectively.
  • the shell-forming high alloy cast steel molten at 1,5l5 C. was first poured into the body of the 5 mold through ,the down sprue 7 and the arbor-forming low alloy steel molten at l,505 C. was concurrently poured into the cylindrical member, corresponding to the arbor 2, through the down sprue 8.
  • the respective metals poured were left to stand in the mold for 7 days for cooling and then removed from the mold upon completion of cooling.
  • the temperature of the roll body portion at the time of removal was 1 10 C.
  • the casting was machined to the dimensions mentioned earlier and thereafter the machined roll was heated to l,050 C. at the rate of 25 C./hour, maintained at said temperature for 20 hours, cooled to 400 C., heated again to 830 C., maintained at that temperature for 20 hours, allowed to cool to 750 C. and maintained at that temperature for 20 hours.
  • the roll was heated to and maintained at 830 C. and
  • FIG. 1 shows the appearance of the finished roll and the body portion of the roll has a cross-sectional structure as shown in FIG. 2 which is a transverse sectional view taken along the line II-II of FIG. 1.
  • FIG. 3 is a microscopic photograph showing the structure at the border of the shell and the partition member
  • FIG. 4 is a microscopic photograph showing the structure at the border of the partition member and the core, the magnification being 400 for both photographs.
  • the roll was produced by the bottom casting method using the apparatus shown in FIG. 5.
  • the shell 1 and the arbor 2 are connected through theintermediary of the partition member 3.
  • the partition member 3 remains in its original shape even after completion of the casting and serves to prevent migration of the shell-forming molten metal and the core-forming molten metal.
  • the shell and the partition member, and the arbor and the partition member are metallurgically bonded with each other on their borders.
  • the body of a mold defining a cavity conforming to the shape of the roll, is provided with a riser gate 4 and the shell portion is composed of a metal mold 5, while the journal-forming portions are composed of sand molds 6.
  • a down sprue 7 is provided for pouring a shell-forming molten metal into the space between the mold and the partition member, while another down sprue 8 is provided for pouring an arbor-forming molten metal into the hollow of the partition member.
  • the hardness of the shell was to in Shore hardness.
  • the tensile strength of the shell was measured on a sample piece cut away from the shell, to find that the tensile strength was to kg./mm.
  • the tensile strength of the connec tion between the partition member, and the shell and the core was about 15 to 25 kg./mm. which is sufficient to withstand the rolling conditions. It was also noted that no internal shrinkage nor internal crack was formed at the boundary between the shell and the partition member and between the core and the partition member, and that the compound cast roll thus produced was less inferior to a solid roll.
  • EXAMPLE 2 A compound cast roll for use as a blooming roll having a diameter of 1,200 mm., a total length of 6,500 mm., a body length of 2,400 mm., a shell thickness of 200 mm. and a partition member thickness of 30 mm. was produced, said partition member extending over the journals of the roll.
  • the mold Upon completion of the pouring, the mold was left to stand for 7 days with the metals cast therein, to allow the cast roll to cool and then the cast roll was removed from the mold.
  • the cast roll was machined to the prescribed dimensions and the compound roll thus machined was heated to 1050 C. at the rate of 25 C./hour, maintained at that temperature for hours, 2
  • the mold Upon completion of the pouring, the mold was left to stand for 7 days, with the metals cast therein, and then the cast roll was removed from the mold. After cutting the gates, the cast roll was machined to the prescribed dimensions, and then heated to 1,050 C. at the rate of 25 C./hour, maintained at 0 thattemperature for 20 hours, cooled to 400 C., heated again to 850 C., maintained at that temperature for 25 hours, and cooled by furnace cooling, to effect annealing of the roll for homogenization of the casting structure, deformation of carbides into spherical shape and removal of the casting stress. Then, the roll was again heated to 980 C., cooled 620 C. in air, maintained at that temperature for hours and then cooled by furnace cooling, to effect quenching and tempering, whereby a necessary hardness and toughness were imparted to the shell.
  • reference numeral 8 designates the journal of the roll.
  • the thickness of the portion of the partition member constituting the surface layer of the journal differs from the thickness of the remaining portion of the same covering the roll body portion, because the portion of the partition member at the journal was ground after the roll had been cast.
  • the compound roll thus produced showed a Shore hardness of 5 7 to 62 on the surface of the shell, a Shore hardness of 40 to 45 at the journals and a Shore hardness of 26 to 29 at the core. It has been verified that the shell and the journals shown sufficiently stable performances as a roll. It was also revealed that the shell and the partition member, and the core and the partition member were connected completely metallurgically,
  • EXAMPLE 3 A compound cast roll adapted for use as a blooming roll and having a diameter of 1,200 mm., a total length of 6,000 mm., a roll body length of 2,000 mm., a shell thickness of 200 mm., and a partition member thickness and length of 25 mm. and 200 mm. respectively, was produced by the following process.
  • a partition member was set in a mold at a location 200 mm. spaced from the inner surface of the roll body-forming cavity of the mold and then a shell-forming high alloy cast steel, molten at l,5l0 C., was poured into a portion of the EXAMPLE 4
  • the mold After casting, the mold was left to stand for 9 days, with the cast metals therein, and then the cast roll was removed from the mold by breaking said mold. After cutting the gates, the cast roll was machined into the prescribed dimensions, and then heated to 1,050 C., maintained at that temperature for 30 hours, cooled to 400 C. in air, heated again to 830 C., maintained at that temperature for 30 hours and cooled by furnace cooling, whereby annealing of the roll was effected for homogenization of the casting structure, deformation of carbides into spherical shape and removal of the casting stress.
  • the roll was again heated to 950 C., cooled in air to 560 C., maintained at that temperature for hours and then cooled by furnace cooling.
  • the shell and the partition member, and the core and the partition member had been completely connected with each other metallurgically, and no internal shrinkages nor internal cracks were found at the boundaries between the shell and core, and the partition member.
  • the surface hardness of the shell was or higher in Shore hardness as desired.
  • the chemical compositions of the shell, the core and the partition member are shown in Table 4 below:
  • EXAMPLE 5 A compound cast roll adapted for use as a work roll and having a diameter of 800 mm., a total length of 4,500 mm., a roll body length of 2,060 mm. and a shell thickness of 80 mm. was produced by the same casting process and heat-treating process as in Example 1.
  • the compound cast roll thus produced was completely free 20
  • the properties required for the shell depend largely on of internal shrinkage or internal crack, and the boundaries between the shell and the partition member and between the core and the partition member showed a complete metallurgical connection.
  • the cast steel hitherto used for the production of a solid cast rollv contains not more than 3 percent by weight of chromium and its structure consists of a mixture of a and (Fe-Cr) In a region defined by a line connecting a point v representing 0.06 percent by weight of carbon and 2.0 percent .by weight of chromium with a point representing 2.6 percent by weight of carbon and 4.5 percent by weight of chromium, and a line connecting said first point with a point representing composition of the cast steel used is shown in Table 6 below:
  • FIG. 7 is a graph showing the hardness distributions of the compound cast roll obtained in Example 1 and the solid cast steel roll obtained in Control Example 1.
  • the hardness distribution was obtained by measuring the hardness at various spots and the distances of the respective spots from the roll surface. As seen, the hardness distribution of each roll has a certain width because since, even when the distance is the same, the hardness was not the same at different spots of measurement, the measurements were taken 8 times in average at a spot and the maximum and the minimum values of hardness at the respective spots were plotted. From the chart of FIG.
  • the surface hardness of the solid cast steel roll is about 60 in Shore hardness, which is slightly low for the roll to be used as a back up roll but is sufficiently high for the roll to be used as a blooming roll and a work roll.
  • This solid cast steel roll has a tendency that the hardness decreases rapidly with the radial distance and such tendency becomes particularly apparent from a distance of 70 mm. and onwards from the roll surface.
  • the structure of the cast steel consists of a mixture of a, (Fe-Cr) C and (Cr-Fe) C and the amount of carbide formed is more than in the case when the chromium content is not more than 3 percent by weight. This substantiates the fact that the hardness of the cast steel increases with the amount of chromium.
  • the structure of the cast steel consists of a mixture of a and (Cr-Fe) C and the amount of chromium carbide formed further increases.
  • the present inventors conducted a further study to determined a region wherein the amount of chromium carbide can be increased without jeopardizing the castability of the steel, and found that the one defined by a line connecting a point A representing 0.2 percent by weight of carbon and 3.0 percent by weight of chromium with a point B representing 0.2 percent by weight of carbon and 8.0 percent by weight of chromium, a line connecting said point B with a point C representing 1.6 percent by weight of carbon and 20.0 percent by weight of chromium, a line connecting said point C with a point D representing 2.6 percent by weight of carbon and 20.0 percent by weight of chromium, a line connecting said point D with a point E representing 2.6 percent by weight of carbon and 4.2 percent by weight of chromium, and a line connecting said point E with said point A, is most preferable.
  • the partition member used in the present invention may be provided in the shapes shown in FIGS. 9 to 16.
  • a partition member shown in FIG. 9 is in the shape of a jointless cylinder of uniform wall thickness and can be produced simply as by centrifugal casting method.
  • a partition member shown in FIG. 10 has a cylindrical inner surface of uniform diameter and a tapered outer surface, and can also be produced simply as by centrifugal casting method.
  • a partition member shown in FIG. 11 has a cylindrical inner and outer surfaces of uniform diameter and consists of a plurality of sections connected with each other by welding.
  • a partition member shown in FIG. 12 has welded joints, not in a longitudinal direction but in a circumferential direction thereof.
  • a partition member shown in FIG. 13 consists of a plurality of sections connected together into a unitary piece by welding, which sections are uniform in inner diameter but difierent in outer diameter.
  • a partition member shown in FIG. 14 consists of a plurality of sections connected together into a unitary piece by welding, which sections are substantially uniform in wall thickness but different in inner and outer diameters.
  • a partition member shown in FIG. 15 consists of a plurality of sections connected with each other by welding into a unitary piece, which sections have parallel inner and outer surfaces but are different in inner and outer diameters, the outer diameter becoming larger as the inner diameter becomes smaller.
  • a partition member shown in FIG. 16 consists of a plurality of sections connected together into a unitary piece by welding, which sections have a uniform outer diameter but different inner diameters.
  • FIG. 19 shows a partition member having a flared top end which is effective for preventing excessive migration of the shell-forming molten metal and the coreforrning molten metal into each other through a space between the partition member and the mold surface.
  • a method of producing a compound cast roll with an outer metal shell having excellent rolling properties and a metal core having excellent toughness comprising the steps of placing a cylindrical partition member having a predetermined diameter in a casting mold, the length of the partition member being approximately equal to that of said shell; pouring a shell-forming molten metal into an annular space between said partition member and said mold; pouring a coreforming molten metal into an interior space formed by said partition member; forming the resultant casting into a desired roll shape by machining and subjecting the formed roll to a heat-treatment operation for imparting the desired rolling properties to the shell and the desired toughness to the core, said partition member having a wall thickness that is reduced from the lower end adjacent the bottom of the mold toward the upper end adjacent the top of the mold whereby solidification of the molten shell-forming and core-forming metals takes place under a positive temperature gradient.
  • a method of producing a compound cast roll as defined in claim I in which said partition member prevents migration of the shell-forming molten metal into the core-forming molten metal and provides a metallurgical bond between said mol ten metals.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Reduction Rolling/Reduction Stand/Operation Of Reduction Machine (AREA)
  • Continuous Casting (AREA)
US844038A 1968-07-26 1969-07-23 A method of producing compound cast rolls Expired - Lifetime US3659323A (en)

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JP5244268A JPS5324371B1 (de) 1968-07-26 1968-07-26
JP343269 1969-01-20

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Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3894325A (en) * 1973-05-11 1975-07-15 Hitachi Metals Ltd Large-sized and thick compound sleeves of high hardness
USRE28868E (en) * 1972-10-05 1976-06-22 United States Steel Corporation Method of forming composite rolls
US4548653A (en) * 1980-10-31 1985-10-22 Union Siderurgique Du Nord Et De L'est De La France (Usinor) Cast cold rolling roll and its method of manufacture
US4610073A (en) * 1982-12-06 1986-09-09 Combustion Engineering, Inc. Trimetal pulverizer roll and a method of manufacture thereof
US5188023A (en) * 1991-10-30 1993-02-23 The Dupps Company Cast formed bi-metallic worm assembly and method
US5207776A (en) * 1991-10-04 1993-05-04 The Babcock & Wilcox Company Bi-metallic extrusion billet preforms and method and apparatus for producing same
US5248289A (en) * 1989-12-13 1993-09-28 Sandvik Ab Cast iron roll with one or more cemented carbide roll rings metallurgically bonded thereto
US5359772A (en) * 1989-12-13 1994-11-01 Sandvik Ab Method for manufacture of a roll ring comprising cemented carbide and cast iron
US5547521A (en) * 1992-11-16 1996-08-20 The Babcock & Wilcox Company Heat treatment method for lost foam cast materials
EP0881019A1 (de) * 1997-05-26 1998-12-02 Wärtsilä NSD Schweiz AG Verfahren zur Herstellung von metallischen Giesslingen, metallischer Giessling, sowie Hubkolbenbrennkraftmaschine
US6013141A (en) * 1995-06-06 2000-01-11 Akers International Ab Cast iron indefinite chill roll produced by the addition of niobium
US20030198827A1 (en) * 2002-04-19 2003-10-23 Hutte Klein-Reichenbach Gesellschaft M.B.H Lightweight part, as well as a process and device for its production
US20070057019A1 (en) * 2005-08-29 2007-03-15 Voith Paper Patent Gmbh Heatable roll and process for making a heatable roll
CN104220192A (zh) * 2012-04-02 2014-12-17 日立金属株式会社 离心铸造制复合辊及其制造方法
CN105579157A (zh) * 2013-09-25 2016-05-11 日立金属株式会社 离心铸造制复合辊及其制造方法
US9387534B2 (en) * 2014-08-29 2016-07-12 Zf Friedrichshafen Ag Control arm and a method for forming the same
CN112139471A (zh) * 2020-09-24 2020-12-29 邢台鸿科高速钢轧辊有限公司 一种棒线材及中宽带钢轧机用轧辊的浇铸箱及使用方法

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2469221A1 (fr) * 1979-11-13 1981-05-22 Usinor Cylindre de laminoir pour train a chaud
GB2435456A (en) * 2006-02-28 2007-08-29 James Richard Yates Machines for manoeuvring trailers

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US288176A (en) * 1883-11-06 Ingtos
US517747A (en) * 1894-04-03 Roll for metal-rolling
US1011430A (en) * 1911-11-10 1911-12-12 John B Henry Method of casting chilled rolls.

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US288176A (en) * 1883-11-06 Ingtos
US517747A (en) * 1894-04-03 Roll for metal-rolling
US1011430A (en) * 1911-11-10 1911-12-12 John B Henry Method of casting chilled rolls.

Cited By (30)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USRE28868E (en) * 1972-10-05 1976-06-22 United States Steel Corporation Method of forming composite rolls
US3894325A (en) * 1973-05-11 1975-07-15 Hitachi Metals Ltd Large-sized and thick compound sleeves of high hardness
US4548653A (en) * 1980-10-31 1985-10-22 Union Siderurgique Du Nord Et De L'est De La France (Usinor) Cast cold rolling roll and its method of manufacture
US4610073A (en) * 1982-12-06 1986-09-09 Combustion Engineering, Inc. Trimetal pulverizer roll and a method of manufacture thereof
US5248289A (en) * 1989-12-13 1993-09-28 Sandvik Ab Cast iron roll with one or more cemented carbide roll rings metallurgically bonded thereto
US5359772A (en) * 1989-12-13 1994-11-01 Sandvik Ab Method for manufacture of a roll ring comprising cemented carbide and cast iron
US5207776A (en) * 1991-10-04 1993-05-04 The Babcock & Wilcox Company Bi-metallic extrusion billet preforms and method and apparatus for producing same
US5188023A (en) * 1991-10-30 1993-02-23 The Dupps Company Cast formed bi-metallic worm assembly and method
US5547521A (en) * 1992-11-16 1996-08-20 The Babcock & Wilcox Company Heat treatment method for lost foam cast materials
WO1996033033A1 (en) * 1995-04-17 1996-10-24 The Babcock & Wilcox Company Heat treatment for lost foam cast materials
US6013141A (en) * 1995-06-06 2000-01-11 Akers International Ab Cast iron indefinite chill roll produced by the addition of niobium
EP0881019A1 (de) * 1997-05-26 1998-12-02 Wärtsilä NSD Schweiz AG Verfahren zur Herstellung von metallischen Giesslingen, metallischer Giessling, sowie Hubkolbenbrennkraftmaschine
US20060113056A1 (en) * 2002-04-19 2006-06-01 Huette Klein-Reichenbach Gesellschaft M.B.H. Lightweight part, as well as process and device for its production
US20060029826A1 (en) * 2002-04-19 2006-02-09 Huette Klein-Reichenbach Gesellschaft M.B.H. Lightweight part, as well as a process and device for its production
US20030198827A1 (en) * 2002-04-19 2003-10-23 Hutte Klein-Reichenbach Gesellschaft M.B.H Lightweight part, as well as a process and device for its production
US7135236B2 (en) 2002-04-19 2006-11-14 Huette Klein-Reichenbach Gesellschaft M.B.H Lightweight part, as well as a process and device for its production
US7134477B2 (en) 2002-04-19 2006-11-14 Huette Klein-Reichenbach Gesellschaft M.B.H Lightweight part, as well as process and device for its production
US7137433B2 (en) * 2002-04-19 2006-11-21 Huette Klein-Reichenbach Gesellschaft M.B.H. Lightweight part, as well as a process and device for its production
US20070057019A1 (en) * 2005-08-29 2007-03-15 Voith Paper Patent Gmbh Heatable roll and process for making a heatable roll
US9044807B2 (en) * 2012-04-02 2015-06-02 Hitachi Metals, Ltd. Centrifugally cast composite roll and its production method
US20140377587A1 (en) * 2012-04-02 2014-12-25 Hitachi Metals, Ltd. Centrifugally cast composite roll and its production method
CN104220192A (zh) * 2012-04-02 2014-12-17 日立金属株式会社 离心铸造制复合辊及其制造方法
CN104220192B (zh) * 2012-04-02 2016-05-11 日立金属株式会社 离心铸造制复合辊及其制造方法
CN105579157A (zh) * 2013-09-25 2016-05-11 日立金属株式会社 离心铸造制复合辊及其制造方法
KR20160060061A (ko) * 2013-09-25 2016-05-27 히타치 긴조쿠 가부시키가이샤 원심 주조제 복합 롤 및 그 제조 방법
US20160193637A1 (en) * 2013-09-25 2016-07-07 Hitachi Metals, Ltd. Centrifugally cast composite roll and its production method
US9724740B2 (en) * 2013-09-25 2017-08-08 Hitachi Metals, Ltd. Centrifugally cast composite roll and its production method
US9387534B2 (en) * 2014-08-29 2016-07-12 Zf Friedrichshafen Ag Control arm and a method for forming the same
CN112139471A (zh) * 2020-09-24 2020-12-29 邢台鸿科高速钢轧辊有限公司 一种棒线材及中宽带钢轧机用轧辊的浇铸箱及使用方法
CN112139471B (zh) * 2020-09-24 2022-04-08 邢台鸿科高速钢轧辊有限公司 一种棒线材及中宽带钢轧机用轧辊的浇铸箱及使用方法

Also Published As

Publication number Publication date
AU5852369A (en) 1971-01-28
DE1937974A1 (de) 1971-02-04
GB1271959A (en) 1972-04-26

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