Hot continuous rolling anti-oxidation high-speed steel roller and preparation method

Abstract

The invention discloses a hot continuous rolling anti-oxidation high-speed steel roller and a preparation method, and belongs to the technical field of rollers, the hot continuous rolling anti-oxidation high-speed steel roller comprises a high-speed steel roller outer layer and a high-speed steel roller core part, the high-speed steel roller outer layer comprises the following chemical components in percentage by weight: 1.2-2.1% of C, 0.3-1.0% of Si, 0.3-1.2% of Mn, less than or equal to 0.1% of P, less than or equal to 0.03% of S, 4.0-8.0% of Cr, 0.5-1.8% of Ni, 2.0-8.0% of Mo, 2.0-8.0% of V and 1.0-6.0% of W; the high-speed steel roller core comprises the following chemical components in percentage by weight: 3.1-3.5% of C, 1.5-2.5% of Si, 0.6-0.7% of Mn, less than or equal to 0.1% of P, less than or equal to 0.03% of S, less than or equal to 0.5% of Cr, less than or equal to 1.0% of Ni, less than or equal to 0.3% of Mo and 0.05-0.08% of Mg. The prepared hot continuous rolling anti-oxidation high-speed steel roller has high wear resistance and good oxidation resistance, and is suitable for various hot continuous rolling anti-oxidation high-speed steel rollers.

Description

Technical Field

[0001] The invention belongs to the technical field of rolling rollers, and in particular to the technical field of rolling roller manufacturing, and specifically relates to a hot rolling anti-oxidation high-speed steel rolling roller and a preparation method thereof. Background Art

[0002] Rollers are the main working parts and tools on the rolling mill that cause continuous plastic deformation of metal. Rollers are mainly composed of three parts: roll body, roll neck and shaft head. The roll body is the middle part of the roll that actually participates in rolling metal. It has a smooth cylindrical or grooved surface. The roll neck is installed in the bearing and transmits the rolling force to the frame through the bearing seat and the pressing device. The drive end shaft head is connected to the gear seat through the connecting shaft to transmit the rotational torque of the motor to the roll. The rolls can be arranged in the form of two rolls, three rolls, four rolls or multiple rolls in the rolling mill frame.

[0003] High-speed steel rolls contain a large amount of alloy elements such as V, W, Cr, Mo, Nb, etc., and have a high room temperature hardness of HS82-90. At the same time, they have good high-temperature red hardness characteristics. They can still guarantee HS78 or above at above 500°C. Therefore, they have excellent high-temperature wear resistance and are currently widely used in steel rolling production. Replacing semi-steel rolls, high-chromium cast iron rolls, high-nickel-chromium-molybdenum infinitely chilled rolls and needle-shaped bainite ductile iron rolls with high-speed steel rolls has achieved good results in production practice in terms of increasing rolling volume and extending roll replacement cycles.

[0004] Although many rolling lines have put high-speed steel rolls into use in batches, there are still more rolling lines that are restricted by the working conditions of the rolling lines. After the high-speed steel rolls were put into use, it was found that the oxide film on the roll surface fell off seriously, and the excellent performance of the high-speed steel rolls could not be brought into play. In some rolling lines, the use effect of high-speed steel rolls is not as good as that of high-chromium iron rolls. Many rolling lines have tried to use precision-rolled high-speed steel rolls, but were forced to stop due to serious oxide film shedding.

[0005] The reason for the oxide film falling off is related to the insufficient cooling capacity of the roll and the excessive growth of the oxide film. Therefore, it is necessary to study the preparation method of anti-oxidation high-speed steel rolls and develop hot rolling oxidation-resistant high-speed steel rolls for the front section of finishing rolling. Summary of the invention

[0006] In order to solve the problem of insufficient cooling capacity of the rollers and excessively thick oxide film growth in the prior art, the present invention provides a hot rolling anti-oxidation high-speed steel roller and a preparation method, which can prevent the oxide film of the high-speed steel roller from falling off, improve the roller surface quality of the high-speed steel roller, improve the roller quality, and reduce the roller consumption.

[0007] The technical solution adopted by the hot rolling anti-oxidation high-speed steel roll and the preparation method of the present invention is:

[0008] A hot rolling anti-oxidation high-speed steel roller, comprising a high-speed steel roller outer layer and a high-speed steel roller core, characterized in that: the weight percentages of different alloys in the chemical composition of the high-speed steel roller outer layer are: C: 1.2-2.1%, Si: 0.3-1.0%, Mn: 0.3-1.2%, P: ≤0.1%, S: ≤0.03%, Cr: 4.0-8.0%, Ni: 0.5-1.8%, Mo: 2.0-8.0%, V: 2.0-8.0%, W: 1.0-6.0%;

[0009] The weight percentages of different alloys in the chemical composition of the high-speed steel roll core are: C: 3.1-3.5%, Si: 1.5-2.5%, Mn: 0.6-0.7%, P: ≤0.1%, S: ≤0.03%, Cr: ≤0.5%, Ni: ≤1.0%, Mo: ≤0.3% and Mg: 0.05-0.08%.

[0010] A further improvement of the technical solution of the present invention is that the material of the outer layer of the high-speed steel roller is high-speed steel, and the weight percentages of Mo, V and W satisfy 0.8≤(Mo+0.5W) / V≤1.5, and the material of the core is ductile iron.

[0011] A method for preparing a hot rolling anti-oxidation high-speed steel roll, used for preparing the hot rolling anti-oxidation high-speed steel roll described above, comprises the following steps:

[0012] S1. Mixing and heating scrap steel, pig iron or carburizer, ferrochrome, ferrotungsten, ferromanganese, ferrosilicon, ferromolybdenum, ferrovanadium and nickel plate to form molten iron for the outer layer of the high-speed steel roll;

[0013] S2, drying the yttrium-based heavy rare earth at 200-220°C, placing it at the bottom of the ladle, and performing rare earth modification treatment on the molten iron of the outer layer of the high-speed steel roll by the ladle-injection method to obtain high-speed steel liquid, which is used to cast the outer layer of the high-speed steel roll after slagging;

[0014] S3, pouring high-speed steel liquid into the centrifuge, centrifugally pouring the outer layer, and sprinkling glass slag, after the outer layer solidifies, pouring the high-speed steel roll core, standing still and completely cooling, and then unpacking to obtain the blank roll;

[0015] S4, rough-processing the blank roll to obtain a rough-processed roll;

[0016] S5. The roughing rolls are gradually heated to 1000-1100℃ and maintained for 50-90min. After the insulation is completed, they are cooled by air jet. Then the roughing rolls are air-cooled. The roll body is air-cooled to 300-400℃ and then loaded into the furnace for tempering. After two temperings, they are unloaded from the furnace for subsequent processing until the finished product.

[0017] A further improvement of the above technical solution of the present invention is that: during the period of mixing, heating and melting the molten iron to form the outer layer of the high-speed steel roller in step S1, the molten iron is sampled, the composition is detected and adjusted, and after the composition is qualified, the temperature is controlled at 1400-1500°C for steel tapping and argon blowing is carried out in time, the argon pressure is 0.3-0.6MPa, and pouring is carried out when the temperature in the ladle is 1300-1400°C.

[0018] The further improvement of the above technical solution of the present invention is that the tapping temperature is controlled at 1400-1500°C, argon is blown to fully stir the molten steel to make the internal temperature of the molten steel uniform and remove slag, improve the cleanliness of the molten steel to prevent internal impurities from entering the cavity to form casting defects, and the pouring temperature is controlled at 1300-1400°C.

[0019] A further improvement of the above technical solution of the present invention is that in the step S4, a reserved amount of 5 to 10 mm is provided in the outer diameter direction of the rough-machined roller, and a reserved amount of 8 to 15 mm is provided in the length direction.

[0020] A further improvement of the above technical solution of the present invention is that when the air jet cooling is adopted after the heat preservation in step S5, the air pressure is maintained at 0.5-0.6MPa, and the air jet cooling is performed for 60-120 minutes and then air cooled to 300-400°C of the roller body and then loaded into the furnace for tempering.

[0021] A further improvement of the above technical solution of the present invention is that in step S5, the roller body is air-cooled to 300-400°C and then loaded into the furnace for tempering, and the tempering temperature is maintained at 500-600°C for 20-50 hours.

[0022] Due to the adoption of the above technical solution, the technical advances achieved by the present invention include:

[0023] The present invention utilizes the strong anti-oxidation effect of W element and combines with other elements to reduce the problem of coarse carbide aggregation caused by the addition of W element. A special heat treatment process is adopted to achieve dispersed distribution of carbides, thereby improving the anti-oxidation ability of high-speed steel rolls and ensuring the uniformity of roll surface quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a metallographic diagram of the hot rolling anti-oxidation high-speed steel roll of the present invention, which is magnified 500 times;

[0025] Figure 2 It is a comparison of the metallographic diagrams of the hot rolling anti-oxidation high-speed steel roll and the conventional high-speed steel in the first embodiment of the present invention;

[0026] Figure 3 The metallographic diagrams of the hot rolling anti-oxidation high-speed steel roll and conventional high-speed steel of the second embodiment of the present invention are compared;

[0027] Figure 4 The metallographic diagrams of the hot rolling anti-oxidation high-speed steel roll and conventional high-speed steel of the third embodiment of the present invention are compared;

[0028] Figure 5 The metallographic diagrams of the hot rolling anti-oxidation high-speed steel roll and conventional high-speed steel of the fourth embodiment of the present invention are compared;

[0029] Figure 6 It is a comparison of the metallographic diagrams of the hot rolling anti-oxidation high-speed steel roll and the conventional high-speed steel of the comparative example 1 of the present invention;

[0030] Figure 7 It is a comparison of the metallographic diagrams of the hot rolling anti-oxidation high-speed steel roll of comparative example 2 of the present invention and conventional high-speed steel. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present invention more clear, the present invention is further described in detail below in combination with specific implementation methods and with reference to the accompanying drawings. In the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0032] The invention provides a hot rolling anti-oxidation high-speed steel roll comprising a high-speed steel roll outer layer and a high-speed steel roll core; wherein the material of the high-speed steel roll outer layer is high-speed steel, and the weight percentages of different alloys in the chemical composition of the high-speed steel roll outer layer are: C: 1.2-2.1%, Si: 0.3-1.0%, Mn: 0.3-1.2%, P: ≤0.1%, S: ≤0.03%, Cr: 4.0-8.0%, Ni: 0.5-1.8%, Mo: 2.0-8.0%, V: 2.0-8.0%, W: 1.0-6.0%, and the weight percentages of Mo, V and W satisfy 0.8≤(Mo+0.5W) / V≤1.5.

[0033] The material of the high-speed steel roll core is ductile iron, and the weight percentages of different alloys in the chemical composition of the high-speed steel roll core are: C: 3.1-3.5%, Si: 1.5-2.5%, Mn: 0.6-0.7%, P: ≤0.1%, S: ≤0.03%, Cr: ≤0.5%, Ni: ≤1.0%, Mo: ≤0.3% and Mg: 0.05-0.08%.

[0034] The present invention also provides a method for preparing a hot rolling anti-oxidation high-speed steel roll, comprising the following steps:

[0035] S1. Mix scrap steel, pig iron or carburizer, ferrochrome, ferrotungsten, ferromanganese, ferrosilicon, ferromolybdenum, ferrovanadium and nickel plate, heat and melt to form molten iron for the outer layer of high-speed steel roll, sample the molten iron to detect the composition and make adjustments. After the composition is qualified, control the temperature at 1400-1500℃ for steel tapping and blow argon in time. The argon pressure is 0.3-0.6MPa. When the temperature in the ladle is 1300-1400℃, pouring is carried out.

[0036] S2. After drying the yttrium-based heavy rare earth at 200-220°C, place it at the bottom of the ladle, and use the ladle flushing method to perform rare earth modification on the molten iron of the outer layer of the high-speed steel roll to obtain high-speed steel liquid, which is used to cast the outer layer of the high-speed steel roll after slag removal.

[0037] S3, pouring high-speed steel liquid into the centrifuge, centrifugally pouring the outer layer, and sprinkling glass slag, after the outer layer solidifies, pouring the high-speed steel roll core, standing still and completely cooling, and then unpacking to obtain the blank roll;

[0038] S4, rough-processing the blank roll to obtain a rough-processed roll, wherein the rough-processed roll has a reserved amount of 5 to 10 mm in the outer diameter direction and a reserved amount of 8 to 15 mm in the length direction;

[0039] S5. The rough-processed rollers are gradually heated to 1000-1100℃ and maintained for 50-90min. After the insulation, they are cooled by air jet with the wind pressure maintained at 0.5-0.6MPa. After 60-120min of air jet cooling, the rollers are air-cooled to 300-400℃ and then loaded into the furnace for tempering. The tempering temperature is maintained at 500-600℃ and maintained for 20-50h. After two temperings, they are unloaded from the furnace for subsequent processing until the finished product.

[0040] Embodiment 1

[0041] The molten steel is melted in an electromagnetic induction furnace. The molten steel temperature reaches 1400℃ and is discharged from the furnace. Centrifugal pouring is performed when the molten steel temperature reaches 1350℃. The actual chemical composition of the outer layer: C: 2.05, Si: 0.72, Mn: 0.47, P: 0.037, S: 0.024, Cr: 4.51, Ni: 1.1, Mo: 5.92, V: 5.28, W: 2.55. Unpacking is performed 70 hours after pouring. According to the rough drawing, 8mm is retained in the diameter direction and 10mm is retained in the length direction. Enter the electric induction heating furnace and gradually heat to 1100℃ and keep warm for 60min. Then transfer to the spray quenching machine for cooling, the wind pressure is 0.6MPa, and the air supply is stopped after 67min. Air cooling is used to charge the furnace for tempering at 350℃, and tempering is performed twice, each time at 550℃ for 20 hours.

[0042] Example 2

[0043] The molten steel is melted in an electromagnetic induction furnace. The molten steel temperature reaches 1420℃ and is discharged from the furnace. Centrifugal pouring is performed when the molten steel temperature reaches 1360℃. The actual chemical composition of the outer layer: C: 2.00, Si: 0.75, Mn: 0.60, P: 0.030, S: 0.025, Cr: 4.11, Ni: 0.54, Mo: 6.94, V: 5.42, W: 2.14. Unpacking is performed 77 hours after pouring. Processing is performed according to the rough drawing, with 8mm in diameter and 10mm in length. Enter the electric induction heating furnace and gradually heat to 1080℃, and keep warm for 70min. Then transfer to the spray quenching machine for cooling, with a wind pressure of 0.6MPa. Stop the air supply after 93min, use air cooling to 360℃ for tempering, and temper twice, each time keeping warm at 560℃ for 28 hours.

[0044] Example 3

[0045] The molten steel is melted in an electromagnetic induction furnace. The molten steel temperature reaches 1430℃ and is discharged from the furnace. Centrifugal pouring is performed when the molten steel temperature reaches 1340℃. The actual chemical composition of the outer layer: C: 1.89, Si: 0.83, Mn: 0.40, P: 0.024, S: 0.017, Cr: 4.78, Ni: 0.56, Mo: 5.51, V: 5.55, W: 2.32. Unpacking is performed 67 hours after pouring. Processing is performed according to the rough drawing, with 8mm in diameter and 10mm in length. Enter the electric induction heating furnace and gradually heat to 1080℃, and keep warm for 90min. Then transfer to the spray quenching machine for cooling, with a wind pressure of 0.6MPa. Stop the air supply after 85min, use air cooling to 300℃ and charge the furnace for tempering. Tempering is performed twice, and each time is kept warm at 570℃ for 35 hours.

[0046] Example 4

[0047] The molten steel is melted in an electromagnetic induction furnace. The molten steel temperature reaches 1410℃ and is discharged from the furnace. Centrifugal pouring is performed when the molten steel temperature reaches 1380℃. The actual chemical composition of the outer layer: C: 1.85, Si: 0.80, Mn: 0.41, P: 0.035, S: 0.018, Cr: 4.01, Ni: 0.58, Mo: 4.21, V: 4.50, W: 2.11. Unpacking is performed 65 hours after pouring. Processing is performed according to the rough drawing, with 8mm in diameter and 10mm in length. Enter the electric induction heating furnace and gradually heat to 1100℃, and keep warm for 85min. Then transfer to the spray quenching machine for cooling, with a wind pressure of 0.6MPa. Stop the air supply after 100min, use air cooling to 310℃ and charge the furnace for tempering. Tempering is performed twice, and each time is kept warm at 540℃ for 50 hours.

[0048] Comparative Example 1

[0049] The molten steel is melted in an electromagnetic induction furnace. The molten steel temperature reaches 1480℃ and is discharged from the furnace. Centrifugal pouring is performed when the molten steel temperature reaches 1350℃. The actual chemical composition of the outer layer: C: 2.05, Si: 0.40, Mn: 0.45, P: 0.030, S: 0.017, Cr: 3.12, Ni: 0.35, Mo: 5.19, V: 4.17, W: 4.15. Unpacking is performed 60 hours after pouring. Processing is performed according to the rough drawing, with 8mm in diameter and 10mm in length. Enter the electric induction heating furnace and gradually heat to 1050℃, and keep warm for 80min. Then transfer to the spray quenching machine for cooling, with a wind pressure of 0.6MPa. Stop the air supply after 90min, use air cooling to 300℃ and charge the furnace for tempering. Tempering is performed twice, and each time is kept warm at 510℃ for 30 hours.

[0050] Comparative Example 2

[0051] The molten steel is melted in an electromagnetic induction furnace. The molten steel temperature reaches 1420℃ and is discharged from the furnace. Centrifugal pouring is performed when the molten steel temperature reaches 1350℃. The actual chemical composition of the outer layer: C: 1.98, Si: 0.43, Mn: 0.43, P: 0.030, S: 0.017, Cr: 3.18, Ni: 0.45, Mo: 5.21, V: 4.51, W: 5.43. Unpacking is performed 65 hours after pouring. Processing is performed according to the rough drawing, with 8mm in diameter and 10mm in length. Enter the electric induction heating furnace and gradually heat to 1030℃, and keep warm for 60min. Then transfer to the spray quenching machine for cooling, with a wind pressure of 0.6MPa. Stop the air supply after 87min, use air cooling to 340℃ for tempering, and temper twice, each time keeping warm at 550℃ for 30 hours.

[0052] refer to Figure 2-Figure 7 It can be seen that the carbides of the rollers produced in Examples 1 to 4 of the present invention are evenly distributed compared with those of the rollers produced in Comparative Examples 1 and 2, avoiding the problem of coarse carbide aggregation; the surfaces of the rollers produced in Examples 1 to 4 are smoother than those of the rollers produced in Comparative Examples 1 and 2.

[0053] In the above embodiment, the present invention provides a hot-rolled anti-oxidation high-speed steel roll and a preparation method, which utilizes the strong anti-oxidation effect of the W element and combines different other elements to reduce the problem of coarse carbide aggregation caused by the addition of the W element, and adopts a special heat treatment process to achieve dispersed distribution of carbides. While improving the anti-oxidation ability of the high-speed steel roll, it also ensures the uniformity of the roll surface quality.

[0054] The above-described embodiments are merely descriptions of preferred implementations of the present invention, and are not intended to limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made by ordinary persons in the art to the technical solution of the present invention should fall within the protection scope of the present invention, and the technical contents for which protection is sought in the present invention have been fully recorded in the claims.

Claims

1. A hot rolling anti-oxidation high-speed steel roll, comprising a high-speed steel roll outer layer and a high-speed steel roll core, characterized in that: The weight percentages of different alloys in the chemical composition of the outer layer of the high-speed steel roller are: C: 1.2-2.1%, Si: 0.3-1.0%, Mn: 0.3-1.2%, P: ≤ 0.1%, S: ≤ 0.03%, Cr: 4.0-8.0%, Ni: 0.5-1.8%, Mo: 2.0-8.0%, V: 2.0-8.0%, W: 1.0-6.0%; The weight percentages of different alloys in the chemical composition of the high-speed steel roll core are: C: 3.1-3.5%, Si: 1.5-2.5%, Mn: 0.6-0.7%, P: ≤0.1%, S: ≤0.03%, Cr: ≤0.5%, Ni: ≤1.0%, Mo: ≤0.3% and Mg: 0.05-0.08%.

2. The hot rolling anti-oxidation high-speed steel roll according to claim 1, characterized in that: The material of the outer layer of the high-speed steel roller is high-speed steel, and the weight percentage of Mo, V and W satisfies 0.8≤(Mo+0.5W) / V≤1.5; the material of the core of the high-speed steel roller is ductile iron.

3. A method for preparing a hot rolling anti-oxidation high-speed steel roll, characterized in that: The method for preparing the hot rolling anti-oxidation high-speed steel roll according to any one of claims 1 to 2 comprises the following steps: S1. Mixing and heating scrap steel, pig iron or carburizer, ferrochrome, ferrotungsten, ferromanganese, ferrosilicon, ferromolybdenum, ferrovanadium and nickel plate to form molten iron for the outer layer of the high-speed steel roll; S2, drying the yttrium-based heavy rare earth at 200-220°C, placing it at the bottom of the ladle, and performing rare earth modification treatment on the molten iron of the outer layer of the high-speed steel roll by the ladle-injection method to obtain high-speed steel liquid, which is used to cast the outer layer of the high-speed steel roll after slagging; S3, pouring high-speed steel liquid into the centrifuge, centrifugally pouring the outer layer, and sprinkling glass slag, after the outer layer solidifies, pouring the high-speed steel roll core, standing still and completely cooling, and then unpacking to obtain the blank roll; S4, rough-processing the blank roll to obtain a rough-processed roll; S5. The roughing rolls are gradually heated to 1000-1100℃ and maintained for 50-90min. After the insulation is completed, they are cooled by air jet. Then the roughing rolls are air-cooled. The roll body is air-cooled to 300-400℃ and then loaded into the furnace for tempering. After two temperings, they are unloaded from the furnace for subsequent processing until the finished product.

4. The method for preparing a hot rolling anti-oxidation high-speed steel roll according to claim 3, characterized in that: During the period of mixing, heating and melting the molten iron to form the outer layer of the high-speed steel roller in step S1, the molten iron is sampled to detect the composition and adjusted. After the composition is qualified, the temperature is controlled at 1400-1500°C for steel tapping and argon blowing is carried out in time. The argon pressure is 0.3-0.6MPa, and pouring is carried out when the temperature in the ladle is 1300-1400°C.

5. The method for preparing a hot rolling anti-oxidation high-speed steel roll according to claim 4, characterized in that: The tapping temperature is controlled at 1400-1500℃, argon is blown to fully stir the molten steel, so that the internal temperature of the molten steel is uniform and the slag is removed, the cleanliness of the molten steel is improved to prevent internal impurities from entering the cavity and forming casting defects, and the pouring temperature is controlled at 1300-1400℃.

6. The method for preparing a hot rolling anti-oxidation high-speed steel roll according to claim 3, characterized in that: In the step S4, the rough-processed roller has a reserved amount of 5 to 10 mm in the outer diameter direction and a reserved amount of 8 to 15 mm in the length direction.

7. The method for preparing a hot rolling anti-oxidation high-speed steel roll according to claim 3, characterized in that: When the heat preservation in step S5 is completed and air jet cooling is adopted, the air pressure is maintained at 0.5-0.6MPa, and air cooling is performed for 60-120min, followed by air cooling until the roller body reaches 300-400°C, and then the roller is loaded into the furnace for tempering.

8. The method for preparing a hot rolling anti-oxidation high-speed steel roll according to claim 3, characterized in that: In step S5, the roller body is air-cooled to 300-400° C. and then put into a furnace for tempering, and the tempering temperature is maintained at 500-600° C. for 20-50 hours.

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