CN109317520B - Composite roll sleeve for steel tube rolling mill and manufacturing method thereof - Google Patents

Abstract

A composite roll sleeve for a steel tube rolling mill and a manufacturing method thereof belong to the technical field of steel rolling. The outer layer material and the inner layer material of the composite roller sleeve are respectively smelted in a medium-frequency induction electric furnace, the chemical composition and the mass fraction of the outer layer material are 2.19-2.35% of C, 0.82-0.97% of B, 0.31-0.38% of Al, 8.87-9.16% of Cr, 3.57-3.76% of Mn, 0.52-0.58% of Te, 0.15-0.23% of Ce, 0.08-0.13% of Ti, 0.05-0.11% of N, 0.13-0.17% of Ca, 0.54-0.70% of Si, < 0.035% of P, < 0.032% of S and the balance of Fe, and the outer layer and the inner layer are compounded into a whole by a centrifugal casting method.

Description

Composite roll sleeve for steel tube rolling mill and manufacturing method thereof

Technical Field

The invention discloses a composite roller sleeve and a preparation method thereof, in particular relates to a composite roller sleeve for a steel tube rolling mill and a manufacturing method thereof, and belongs to the technical field of steel rolling.

Background

Since the 50 s of the 20 th century, continuous rolling pipe production technology has been developed greatly due to the breakthrough of transmission technology and electric control technology. The operation modes of the mandrel are from a floating mandrel mill to a retained mandrel mill and a semi-floating mandrel mill, the number of racks is reduced from 9-7 to 6-5, the rolling process is changed from 2 rollers to 3 rollers, the operation mode of the production process is from manual operation to regional automation to a full-automatic operation mode in which the whole line is controlled by a CPU and a PLC, a hydraulic small-bin control technology is adopted, a process control software technology is matched, and the whole equipment level of the continuous tube mill is greatly improved.

Compared with other machine types, the continuous pipe rolling mill has the characteristics of high quality, high yield, high efficiency, low consumption and the like, and becomes the preferred machine type of main production enterprises of the world seamless steel pipes. More than 20 sets of continuous rolling tube mills are newly built in the world in the last 10 years, so far, more than 80 sets of continuous rolling tube mills are available in the world, the capacity of the continuous rolling tube mills is far higher than that of other types, and the continuous rolling tube mills become the mainstream types of seamless steel tube production. The continuous tube rolling mill is introduced into Germany in the early 80 s of the 20 th century and the construction of Bao steelFloating mandrel mill for continuous rolling of tubes, more advanced from Italy introduced by Tianjin tubes Ltd in the early 90 sRetained mandrel mill for continuous rolling of tubes, and subsequently, Hengyang tube mills were introduced in GermanySemi-floating mandrel mill for continuous rolling of tubes. In the 21 st century, with the rapid increase of steel pipe demand, enterprises such as steel-clad, saddle steel, Tianjin steel pipe, Hengyang steel pipe, Chengdu seamless steel pipe and the like have introduced sets of tandem rolling mills in sequence. The high-performance roller sleeve is urgently needed for the production of a large number of steel tube rolling mills, and the requirements of the steel tube rolling mills are met. In order to improve the performance of the roller shell,

the Chinese invention patent CN1350890 discloses a sleeve-inlaid roller product, which is formed by combining a roller sleeve and a roller core, and is characterized in that: the roller sleeve is composed of an outer layer, a transition layer and an inner layer which are made of different materials, wherein the transition layer separates the outer layer from the inner layer so that the outer layer and the inner layer are not in direct contact with each other, and the transition layer and the inner layer are respectively fused together in a metallurgical sense to form a three-layer composite roller sleeve. The outer layer of the roller sleeve is made of a high-alloy metal material with excellent wear resistance and surface roughness resistance, and the roller sleeve comprises the following chemical components in percentage by weight: 1.0 to 3.4% of C, 0.5 to 3.2% of Si, 0.4 to 1.2% of Mn0, 2 to 19% of Cr, 0.4 to 8% of Mo0.4, and further contains one or more of V8% or less, Nb 4% or less, W4% or less, Ni 5% or less, Co 6% or less, and N0.2% or less, and the balance of Fe and unavoidable impurities. The roll sleeve transition layer comprises the following chemical components in percentage by weight: 0.6 to 2.8% of C, 0.4 to 2.9% of Si,0.3 to 1.2% of Mn0.3, less than or equal to Cr 10%, less than or equal to Mo 2%, less than or equal to V2%, less than or equal to Nb 2%, less than or equal to Ni1.6%, and the balance of Fe and inevitable impurities. The Chinese patent CN 106825516 also discloses a roller composite roller sleeve manufacturing process and equipment, wherein an induction heater is adopted to heat the whole thick-wall hollow steel pipe core rod arranged in a combined water-cooled crystallizer to 800-1000 ℃, the working layer melt of a roller shaft is poured in, the heating is continued for 10-50 minutes, a lifting device is started to lift the heater upwards at a certain speed, the heater is lifted to a heat-insulating ring for 5-15 minutes and is stopped, the heating is continued for 10-50 minutes, a riser is fed, and water is introduced for cooling for 30-24 minutes after the heating is stopped. The composite roll sleeve manufactured by the invention has the advantages of few controllable process parameters, easy control of the composite layer interface, simple process, high efficiency, low power consumption, no component segregation of the composite layer and long service life. Overcomes the defects that the centrifugal method is easy to generate tissue segregation, and the traditional insert casting method has poor performance and high cost. The chinese utility model patent 200920247114.0 also discloses a thick-wall bimetal roller sleeve combined roller, which comprises a bearing support ring, a compression ring, a roller sleeve and a mandrel. Heating the bearing support ring (1) and the roller sleeve (3) and then performing interference fit with the mandrel (4), processing the outer diameter of the joint of the bearing support ring (1) and the roller sleeve (3) to the same size, and simultaneously keeping interference connection with the compression ring (2); the thickness of the roller sleeve (3) is phi D which is the diameter of the roller body of the roller, and phi D which is the diameter of the roller neck of the roller. The utility model discloses a stable in structure has solved the roller shell roll and has used the easy cracked problem of roller shell, has expanded the application range of roller shell roll, compares with whole roll, and roll life can improve at double, can change greatly after finishing using and use for a long time, and the noble alloy of back of scrapping can all be retrieved, and the security in the use is ensured to high toughness materials such as inlayer adoption seamless steel pipe, and this combination roll energy saving and consumption reduction, cost reduction and efficiency increase effect are showing. The Chinese patent of invention CN1339342 also discloses a method for manufacturing a high-speed steel roller sleeve, which is characterized in that a high-speed steel electrode capillary is manufactured firstly, then the high-speed steel electrode capillary is placed in roller sleeve electroslag remelting equipment with a chilling crystallizer for electroslag remelting to be manufactured into a blank, and then heat treatment and machining are carried out. The invention has the advantages that: the roller sleeve has fine crystal grains, uniform structure, less inclusions, no defects of shrinkage cavity, looseness, element segregation and the like, can greatly improve the comprehensive properties of wear resistance, toughness and the like, prolongs the service life, and has reasonable and simple process, less investment, low manufacturing method and low cost. Can overcome the defects of manufacturing rollers or roller sleeves by the existing centrifugal casting method, CPC method and the like, and further improve the wear resistance and the toughness. Can be used for manufacturing roll sleeves and rolls of steel tube rolling mills, high-speed wire rod pre-finishing mills, narrow-band finishing mills, small rolling mills and the like. The Chinese patent CN108677083 also discloses a production method of the alloy roll collar for producing the hot-rolled seamless steel tube. The alloy roll collar is composed of an outer layer and an inner layer which are of a centrifugal composite structure, wherein the outer layer of the roll collar is made of high-manganese molybdenum cast iron, and the inner layer of the roll collar is made of graphite steel. The production method of the alloy roll collar adopts a centrifugal composite casting process, and the process scheme also comprises the following steps: spraying of centrifugal cold type coating, smelting and modification treatment of molten metal, centrifugal casting, pit heat preservation and heat treatment. The working layer is made of high-manganese molybdenum cast iron, and the characteristics of high-hardness and high-strength carbide elements of manganese and the high toughness and wear resistance of molybdenum are fully utilized, so that the high-strength, high-wear resistance and cold and hot fatigue resistance of the high-manganese molybdenum cast iron are realized, the production cost is reduced by 10-15% compared with that of a common pearlite and bainite roll collar, the service life of the high-manganese molybdenum cast iron can be prolonged by 2-3 times, and the high-manganese molybdenum cast iron can replace the traditional pearlite and bainite roll collar. The Chinese invention patent CN108660361 also discloses a high-speed steel roll collar for hot-rolled seamless steel pipes and a preparation method thereof, the high-speed steel molten steel is smelted in a medium-frequency induction furnace, and the chemical composition of the high-speed steel molten steel is adjusted: 3.22-3.45% of C, 1.07-1.22% of W, 2.39-2.61% of Mo, 1.55-1.86% of V, 12.44-12.67% of Cr, 0.37-0.54% of Mn, 0.63-0.87% of Si, 0.29-0.41% of Al, less than or equal to 0.035% of S, less than or equal to 0.035% of P and the balance of Fe, when the temperature of the molten steel reaches 1586-.

However, various roller sleeves which have been successfully developed at present generally have the defects of low hardness of the roller surface, poor wear resistance, high brittleness of the roller sleeve and easy cracking in use.

Disclosure of Invention

The invention aims to cast a wear-resistant outer layer of the composite roll sleeve on a centrifugal casting machine, then cast an inner layer of the roll sleeve with good toughness and excellent casting performance, the outer layer and the inner layer are cast and formed under the action of centrifugal force, the inner layer and the outer layer realize good metallurgical bonding, and the structure of the composite roll sleeve is compact. The composite roll sleeve can be realized by the following process steps:

firstly, smelting an outer layer material and an inner layer material of the composite roller sleeve in a medium-frequency induction electric furnace respectively, wherein the chemical composition and the mass fraction of the outer layer material are 2.19-2.35% of C, 0.82-0.97% of B, 0.31-0.38% of Al, 8.87-9.16% of Cr, 3.57-3.76% of Mn, 0.52-0.58% of Te, 0.15-0.23% of Ce, 0.08-0.13% of Ti, 0.05-0.11% of N, 0.13-0.17% of Ca, 0.54-0.70% of Si, < 0.035% of P, < 0.032% of S and the balance of Fe; when the temperature of the outer layer molten iron reaches 1462-; after the outer layer molten iron is poured for 2-3 minutes, measuring the temperature of the inner surface of the outer layer of the composite roller sleeve by using a non-contact temperature measuring instrument, and when the temperature is 1315-1345 ℃, continuously pouring the inner layer molten metal in a metal casting mould on a centrifuge, wherein the chemical composition and the mass fraction of the inner layer molten metal are 1.41-1.57% of C, 1.27-1.43% of Si, 0.25-0.38% of Mo, 0.77-0.94% of Cr, 1.69-1.85% of Mn, 0.008-0.013% of B, 0.07-0.11% of Y,0.035-0.052 of Nb, 0.035-0.052% of Ti, 0.075% of Ti and Nb, less than or equal to 0.095% of P, 0.032% of P, less than 0.030% of S and the balance of Fe; the pouring temperature of the inner layer molten metal is 1502-1519 ℃; adding a stream-following inoculant which accounts for 2.0-2.5% of the mass of the inner layer molten metal entering the metal mold along with the stream in the process of pouring the inner layer molten metal into the metal mold; the chemical composition and the mass fraction of the stream-following inoculant are 46.13-48.69% of Si, 1.08-1.44% of Ti, 2.50-2.76% of La, 3.51-3.75% of Ca, 4.18-4.43% of Ba and the balance of Fe; when the inner layer molten metal is completely solidified, stopping the centrifugal machine, and taking out the roller sleeve blank from the centrifugal machine;

secondly, rough machining is carried out on the roller sleeve blank after sand removal and polishing; heating the rough-machined roller sleeve to 1035 ℃ along with the furnace, preserving heat for 150-.

The composite roll sleeve for the steel tube rolling mill is produced by adopting a centrifugal casting method, and the obtained roll sleeve has compact structure. The outer layer material and the inner layer material of the composite roller sleeve are respectively smelted in a medium-frequency induction furnace, the process is simple and convenient, and the components and the temperature of molten metal are easy to control. The outer layer material has the chemical composition and mass fraction of 2.19-2.35% of C, 0.82-0.97% of B, 0.31-0.38% of Al, 8.87-9.16% of Cr, 3.57-3.76% of Mn, 0.52-0.58% of Te, 0.15-0.23% of Ce, 0.08-0.13% of Ti, 0.05-0.11% of N, 0.13-0.17% of Ca, 0.54-0.70% of Si,<0.035％P,<0.032％s, and the balance Fe. Wherein 0.82-0.97% B is added, mainly to obtain high hardness M₂And B, the quantity of the wear-resistant hard phases in the outer layer material of the composite roll sleeve is favorably improved, so that the wear resistance is favorably improved. In addition, 0.31-0.38% Al is added to promote M₂B is distributed in an isolated way, so that the outer layer of the roller sleeve has good obdurability. The aluminum is a non-carbide and boride forming element and is mainly dissolved in the metal matrix in a solid manner, so that the high-temperature hardness of the matrix can be obviously improved, and the obvious improvement of the high-temperature wear resistance of the outer layer of the composite roll sleeve is promoted.

8.87-9.16% of Cr, 3.57-3.76% of Mn and 0.52-0.58% of Te are added, so that the hardenability of the outer layer of the roller sleeve can be further improved, and the wear resistance of the roller sleeve is improved. 0.15-0.23% of Ce, 0.08-0.13% of Ti, 0.05-0.11% of N and 0.13-0.17% of Ca are added, so that the solidification structure can be further refined, the forms of hard phases and inclusions can be improved, and the hard phases and the inclusions can be uniformly distributed, thereby being beneficial to obviously improving the toughness of the outer layer of the composite roll sleeve. When the temperature of the outer layer molten iron reaches 1462-1479 ℃, the outer layer molten iron is poured into a high-speed rotating metal casting mold on a horizontal centrifuge, the rotating speed of the metal casting mold is 1020-1060rpm, the temperature of the metal casting mold is 213-239 ℃, and the inner surface of the metal casting mold is coated with zircon powder coating with the thickness of 1.5-2.2mm, so that the outer layer solidification structure is fine and compact, and the surface of the outer layer is smooth. And after the outer layer molten iron is poured for 2-3 minutes, measuring the inner surface temperature of the outer layer of the composite roller sleeve by using a non-contact type temperature measuring instrument, and continuously pouring the inner layer molten metal in a metal casting mould on the centrifuge when the temperature is 1315-1345 ℃, so that the inner layer and the outer layer can be ensured to realize good metallurgical bonding. The inner layer molten metal comprises, by mass, 1.41-1.57% of C, 1.27-1.43% of Si, 0.25-0.38% of Mo, 0.77-0.94% of Cr, 1.69-1.85% of Mn, 0.008-0.013% of B, 0.07-0.11% of Y, 0.035-0.052% of Nb, 0.035-0.052% of Ti, 0.075% or more and 0.095% or less of Ti + Nb, 0.032% of P, 0.030% of S and the balance of Fe. The inner layer molten metal contains 1.41-1.57% of C, 1.27-1.43% of Si, 0.25-0.38% of Mo, 0.77-0.94% of Cr and 1.69-1.85% of Mn, so that the inner layer material has high strength, the casting performance of the inner layer material is good, and the inner layer molten metal can be firmly metallurgically bonded with the outer layer material.

The inner layer molten metal also contains 0.008-0.013% of B, 0.07-0.11% of Y, 0.035-0.052% of Nb, 0.035-0.052% of Ti, and the sum of Ti and Nb is more than or equal to 0.075% and less than or equal to 0.095%, so that the solidification structure of the inner layer material can be refined, and the toughness of the inner layer material can be improved. In addition, the pouring temperature of the inner layer molten metal is 1502-1519 ℃, in the process of pouring the inner layer molten metal into the metal mold, a stream-following inoculant accounting for 2.0-2.5% of the mass of the inner layer molten metal entering the metal mold is added along with the stream, the chemical composition and the mass fraction of the stream-following inoculant are 46.13-48.69% of Si, 1.08-1.44% of Ti, 2.50-2.76% of La, 3.51-3.75% of Ca, 4.18-4.43% of Ba and the balance of Fe, so that after the inner layer material is solidified, brittle carbides are not generated, fine dotted graphite is generated, and the inner layer material is ensured to have excellent comprehensive mechanical properties.

And when the inner layer molten metal is completely solidified, stopping the centrifugal machine, taking out the roller sleeve blank from the centrifugal machine, and performing rough machining on the roller sleeve blank after sand removal and polishing. The roller sleeve after rough machining is heated to 1035 ℃ along with the furnace, heat preservation is carried out for 180 minutes, pearlite in the roller sleeve structure is completely austenitized, and the roller surface is air-cooled after the roller sleeve is taken out of the furnace, so that the low-hardness pearlite structure is prevented. When the temperature of the roller surface is reduced to 350-400 ℃, the roller sleeve is placed into the furnace to be reheated to 530-545 ℃ so as to prevent the roller sleeve from cracking. After the temperature is preserved for 480 and 550 minutes, the furnace is cooled to the temperature lower than 120 ℃, and the furnace is taken out and air-cooled to the room temperature, so that the internal stress of the roller sleeve can be eliminated, and the structure is stabilized. And finally, performing finish machining on the roller sleeve to the specified size and precision to obtain the composite roller sleeve for the steel pipe rolling mill, which has excellent comprehensive performance.

Compared with the prior art, the invention has the following advantages:

1. the composite roller sleeve does not contain expensive alloy elements such as vanadium, tungsten, nickel, cobalt and the like, so that the production cost of the roller sleeve is low;

2. the smelting, casting and heat treatment process of the composite roll sleeve is simple and convenient, and large-scale production is easy to realize;

3. the composite roll sleeve inner layer and the composite roll sleeve outer layer realize good metallurgical bonding, the hardness of the composite roll sleeve outer layer is high and is more than 86HSD, the hardness uniformity is good, the hardness difference of the roll surface is less than 1.8HSD, the tensile strength of the roll sleeve outer layer is more than 600MPa, and the interior of the roll sleeve is provided with a high-strength steel wireThe layer impact toughness is more than 25J/cm²；

4. The composite roll sleeve is used on a steel pipe rolling mill, is safe and reliable to use, has no cracking and stripping phenomena in use, has the service life prolonged by more than 3 times than that of a high-chromium cast iron roll sleeve, and has good economic and social benefits when being popularized and applied.

Drawings

FIG. 1 is a schematic view of a composite roll shell structure

1-an outer layer; 2-inner layer.

Detailed Description

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples.

Example 1

The composite roll sleeve for the steel tube rolling mill consists of an outer layer 1 and an inner layer 2, wherein the outer layer 1 and the inner layer 2 are compounded into a whole by a centrifugal casting method, and the composite roll sleeve can be realized by the following process steps:

firstly, smelting an outer layer 1 material and an inner layer 2 material of the composite roller sleeve in a 500 kg medium frequency induction electric furnace respectively, wherein the chemical composition and the mass fraction of the outer layer 1 material are 2.19% of C, 0.97% of B, 0.31% of Al, 9.16% of Cr, 3.57% of Mn, 0.58% of Te, 0.15% of Ce, 0.13% of Ti, 0.11% of N, 0.17% of Ca, 0.54% of Si, 0.033% of P, 0.027% of S and the balance of Fe; when the temperature of the molten iron of the outer layer 1 reaches 1479 ℃, firstly, pouring the molten iron of the outer layer 1 into a high-speed rotating metal casting mold on a horizontal centrifuge, wherein the rotating speed of the metal casting mold is 1020rpm, the temperature of the metal casting mold is 213 ℃, and the inner surface of the metal casting mold is coated with zircon powder coating with the thickness of 1.9-2.2 mm; after the outer layer 1 is poured with molten iron for 3 minutes, measuring the temperature of the inner surface of the outer layer 1 of the composite roll sleeve by using a non-contact temperature measuring instrument, and when the temperature is 1333-1345 ℃, continuously pouring the molten metal of the inner layer 2 in a metal casting mould on a centrifuge, wherein the molten metal of the inner layer 2 comprises 1.57% of C, 1.27% of Si, 0.38% of Mo, 0.77% of Cr, 1.85% of Mn, 0.008% of B, 0.11% of Y, 0.035% of Nb, 0.052% of Ti, 0.075% or more of Ti and Nb or less than 0.095%, 0.031% of P, 0.022% of S and the balance of Fe; the pouring temperature of the molten metal of the inner layer 2 is 1519 ℃; adding a stream-following inoculant which accounts for 2.5 percent of the mass of the inner layer molten metal entering the metal casting mold along with the stream in the process of pouring the inner layer 2 molten metal into the metal casting mold; the chemical composition and the mass fraction of the stream-following inoculant are 48.69% of Si, 1.08% of Ti, 2.76% of La, 3.51% of Ca, 4.43% of Ba and the balance of Fe; when the molten metal of the inner layer 2 is completely solidified, stopping the centrifugal machine, and taking out the roller sleeve blank from the centrifugal machine;

secondly, rough machining is carried out on the roller sleeve blank after sand removal and polishing; heating the rough-machined roller sleeve to 1020 ℃ along with the roller sleeve, preserving heat for 180 minutes, discharging the roller sleeve from the furnace, carrying out air cooling on the roller surface, when the temperature of the roller surface is reduced to 350-370 ℃, charging the roller sleeve into the furnace, reheating to 545 ℃, preserving heat for 480 minutes, cooling the roller sleeve to a temperature lower than 120 ℃, discharging the roller sleeve from the furnace, carrying out air cooling to room temperature, and finally carrying out finish machining to a specified size and precision to obtain the composite roller sleeve for the steel tube rolling mill, wherein the mechanical properties are shown in Table 1.

Example 2

The composite roll sleeve for the steel tube rolling mill consists of an outer layer 1 and an inner layer 2, wherein the outer layer 1 and the inner layer 2 are compounded into a whole by a centrifugal casting method, and the composite roll sleeve can be realized by the following process steps:

firstly, smelting an outer layer 1 material and an inner layer 2 material of the composite roller sleeve in a 750 kg medium frequency induction furnace respectively, wherein the outer layer 1 material comprises 2.35% of C, 0.82% of B, 0.38% of Al, 8.87% of Cr, 3.76% of Mn, 0.52% of Te, 0.23% of Ce, 0.08% of Ti, 0.05% of N, 0.13% of Ca, 0.70% of Si, 0.030% of P, 0.031% of S and the balance of Fe by mass; when the temperature of the molten iron on the outer layer 1 reaches 1462 ℃, firstly pouring the molten iron on the outer layer 1 into a high-speed rotating metal casting mold on a horizontal centrifuge, wherein the rotating speed of the metal casting mold is 1020rpm, the temperature of the metal casting mold is 239 ℃, and the inner surface of the metal casting mold is coated with zircon powder coating with the thickness of 1.5-1.7 mm; after the outer layer 1 is poured with molten iron for 2 minutes, measuring the temperature of the inner surface of the outer layer 1 of the composite roller sleeve by using a non-contact temperature measuring instrument, and when the temperature is 1315-1324 ℃, continuously pouring the molten metal of the inner layer 2 in a metal casting mould on a centrifuge, wherein the molten metal of the inner layer 2 comprises 1.41 percent of C,1.43 percent of Si,0.25 percent of Mo,0.94 percent of Cr,1.69 percent of Mn,0.013 percent of B,0.07 percent of Y,0.052 percent of Nb, 0.035 percent of Ti,0.075 percent of Ti and Nb, 0.095 percent of P,0.027 percent of S and the balance of Fe; the pouring temperature of the molten metal of the inner layer 2 is 1502 ℃; adding a stream-following inoculant which accounts for 2.0 percent of the mass of the inner layer molten metal entering the metal casting mold along with the stream in the process of pouring the inner layer 2 molten metal into the metal casting mold; the stream inoculant comprises 46.13% of Si, 1.44% of Ti, 2.50% of La, 3.75% of Ca, 4.18% of Ba and the balance of Fe by mass percent; when the molten metal of the inner layer 2 is completely solidified, stopping the centrifugal machine, and taking out the roller sleeve blank from the centrifugal machine;

secondly, rough machining is carried out on the roller sleeve blank after sand removal and polishing; heating the rough-machined roller sleeve to 1035 ℃ along with the furnace, preserving heat for 150 minutes, discharging the roller sleeve from the furnace, carrying out air cooling on the roller surface, when the temperature of the roller surface is reduced to 385-400 ℃, putting the roller sleeve into the furnace, reheating to 530 ℃, preserving heat for 480 minutes, cooling the furnace to the temperature lower than 120 ℃, discharging the roller sleeve from the furnace, carrying out air cooling to room temperature, and finally carrying out finish machining to the specified size and precision to obtain the composite roller sleeve for the steel tube rolling mill, wherein the mechanical properties are shown in Table 1.

Example 3

The composite roll sleeve for the steel tube rolling mill consists of an outer layer 1 and an inner layer 2, wherein the outer layer 1 and the inner layer 2 are compounded into a whole by a centrifugal casting method, and the composite roll sleeve can be realized by the following process steps:

firstly, smelting an outer layer 1 material and an inner layer 2 material of the composite roller sleeve in a 1000 kg medium frequency induction electric furnace respectively, wherein the outer layer 1 material comprises 2.27% of C, 0.88% of B, 0.36% of Al, 9.05% of Cr, 3.63% of Mn, 0.55% of Te, 0.19% of Ce, 0.11% of Ti, 0.08% of N, 0.14% of Ca, 0.63% of Si, 0.029% of P, 0.021% of S and the balance of Fe by mass; when the temperature of the molten iron on the outer layer 1 reaches 1470 ℃, firstly pouring the molten iron on the outer layer 1 into a high-speed rotating metal casting mold on a horizontal centrifuge, wherein the rotating speed of the metal casting mold is 1050rpm, the temperature of the metal casting mold is 224 ℃, and the inner surface of the metal casting mold is coated with zircon powder coating with the thickness of 1.7-1.9 mm; after the molten iron of the outer layer 1 is poured for 2.5 minutes, measuring the temperature of the inner surface of the outer layer 1 of the composite roller sleeve by using a non-contact type thermodetector, when the temperature is 1322-1331 ℃, continuously pouring the molten metal of the inner layer 2 in a metal casting mould on a centrifugal machine, wherein the molten metal of the inner layer 2 comprises 1.46 percent of C,1.30 percent of Si,0.29 percent of Mo,0.85 percent of Cr,1.77 percent of Mn,0.009 percent of B,0.08 percent of Y,0.046 percent of Nb, 0.040 percent of Ti, more than or equal to 0.075 percent of Ti and less than or equal to 0.095 percent of Nb, 0.026 percent of P,0.019 percent of S and the balance of Fe; the pouring temperature of the molten metal of the inner layer 2 is 1508 ℃; adding a stream-following inoculant which accounts for 2.2 percent of the mass of the inner layer molten metal entering the metal mold along with the stream in the process of pouring the inner layer 2 molten metal into the metal mold; the chemical composition and the mass fraction of the stream-following inoculant are 47.54 percent of Si,1.27 percent of Ti,2.59 percent of La,3.65 percent of Ca,4.27 percent of Ba and the balance of Fe; when the molten metal of the inner layer 2 is completely solidified, stopping the centrifugal machine, and taking out the roller sleeve blank from the centrifugal machine;

secondly, rough machining is carried out on the roller sleeve blank after sand removal and polishing; and heating the rough-machined roller sleeve to 1030 ℃ along with the roller sleeve, preserving heat for 160 minutes, discharging the roller sleeve from the furnace, carrying out air cooling on the roller surface, when the temperature of the roller surface is reduced to 370-plus-390 ℃, putting the roller sleeve into the furnace, reheating to 540 ℃, preserving heat for 520 minutes, cooling the roller sleeve to a temperature lower than 120 ℃, discharging the roller sleeve from the furnace, carrying out air cooling to room temperature, and finally carrying out finish machining to a specified size and precision to obtain the composite roller sleeve for the steel tube rolling mill, wherein the mechanical properties are shown in Table 1.

TABLE 1 mechanical Properties of composite roll covers

The composite roller sleeve does not contain expensive alloy elements such as vanadium, tungsten, nickel, cobalt and the like, and the production cost of the roller sleeve is low. The composite roll sleeve inner layer and the composite roll sleeve outer layer realize good metallurgical bonding, the hardness of the composite roll sleeve outer layer is high and is more than 86HSD, the hardness uniformity is good, the hardness difference of the roll surface is less than 1.8HSD, the tensile strength of the roll sleeve outer layer is more than 600MPa, and the impact toughness of the roll sleeve inner layer is more than 25J/cm². The composite roll sleeve is used on a steel tube rolling mill, is safe and reliable to use, has no cracking and stripping phenomena in use, and has the service life longer than that of a high-chromium cast iron roll sleeve by more than 3 times.

Claims (2)

1. A preparation method of a composite roll sleeve for a steel tube rolling mill is characterized by comprising the following steps:

firstly, smelting an outer layer material and an inner layer material of the composite roller sleeve in a medium-frequency induction electric furnace respectively, wherein the chemical composition and the mass fraction of the outer layer material are 2.19-2.35% of C, 0.82-0.97% of B, 0.31-0.38% of Al, 8.87-9.16% of Cr, 3.57-3.76% of Mn, 0.52-0.58% of Te, 0.15-0.23% of Ce, 0.08-0.13% of Ti, 0.05-0.11% of N, 0.13-0.17% of Ca, 0.54-0.70% of Si, < 0.035% of P, < 0.032% of S and the balance of Fe; when the temperature of the outer layer molten iron reaches 1462-; after the outer layer molten iron is poured for 2-3 minutes, measuring the temperature of the inner surface of the outer layer of the composite roller sleeve by using a non-contact temperature measuring instrument, and when the temperature is 1315-1345 ℃, continuously pouring the inner layer molten metal in a metal casting mould on a centrifuge, wherein the chemical composition and the mass fraction of the inner layer molten metal are 1.41-1.57% of C, 1.27-1.43% of Si, 0.25-0.38% of Mo, 0.77-0.94% of Cr, 1.69-1.85% of Mn, 0.008-0.013% of B, 0.07-0.11% of Y,0.035-0.052 of Nb, 0.035-0.052% of Ti, 0.075% of Ti and Nb, less than or equal to 0.095% of P, 0.032% of P, less than 0.030% of S and the balance of Fe; the pouring temperature of the inner layer molten metal is 1502-1519 ℃; adding a stream-following inoculant which accounts for 2.0-2.5% of the mass of the inner layer molten metal entering the metal mold along with the stream in the process of pouring the inner layer molten metal into the metal mold; the chemical composition and the mass fraction of the stream-following inoculant are 46.13-48.69% of Si, 1.08-1.44% of Ti, 2.50-2.76% of La, 3.51-3.75% of Ca, 4.18-4.43% of Ba and the balance of Fe; when the inner layer molten metal is completely solidified, stopping the centrifugal machine, and taking out the roller sleeve blank from the centrifugal machine;

secondly, rough machining is carried out on the roller sleeve blank after sand removal and polishing; heating the rough-machined roller sleeve to 1035 ℃ along with the furnace, preserving heat for 150-.

2. A composite sleeve for a steel pipe rolling mill produced by the production method according to claim 1.