CN110904382A - Novel YM5 series cold roll steel and preparation method thereof - Google Patents
Novel YM5 series cold roll steel and preparation method thereof Download PDFInfo
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- CN110904382A CN110904382A CN201811078882.8A CN201811078882A CN110904382A CN 110904382 A CN110904382 A CN 110904382A CN 201811078882 A CN201811078882 A CN 201811078882A CN 110904382 A CN110904382 A CN 110904382A
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/005—Modifying the physical properties by deformation combined with, or followed by, heat treatment of ferrous alloys
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/38—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for roll bodies
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- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
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- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
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- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
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Abstract
The invention provides novel YM5 series cold roll steel and a preparation method thereof, and relates to the technical field of cold rolls. The invention is prepared from the following raw materials in percentage by weight: c is 0.60-0.75%; si is 0.10-0.80%; mn is 0.20-0.90%; 4.5 to 5.5 percent of Cr; ni: less than or equal to 1.0 percent; mo is 1.00-2.0%; v is 0.10-1.00%; s is less than or equal to 0.015 percent; p is less than or equal to 0.015 percent; the balance being Fe. The method adopts measures of reducing the content of C, improving the content of Cr, Mo and V and the like, and effectively solves the problems of insufficient hardness uniformity of the roller body of the roller, insufficient depth of an effective hardening layer, reduced wear resistance and the like.
Description
Technical Field
The invention relates to the technical field of cold rolls, in particular to novel YM5 series cold roll steel and a preparation method thereof.
Background
The cold roll commonly used in China is made of alloy steel such as 9Cr2Mo, 9Cr3Mo and MC3 and the like through processes of quenching tempering, surface quenching and the like, the manufactured roll body is insufficient in hardness uniformity, the depth of an effective hardening layer is insufficient, the wear resistance is reduced, in addition, the carbon content is high, primary carbide is easy to generate, namely liquation, and further the phenomena of surface stripping, roll sticking, short service life of the roll and the like are generated in the rolling process of the roll, so that the surface quality of a plate is influenced.
Disclosure of Invention
Aiming at the defects existing in the problems, the invention provides the novel YM5 series cold roll steel and the preparation method thereof, which adopt the measures of reducing the content of C, improving the content of Cr, Mo and V and the like, and effectively solve the problems of insufficient uniformity of the hardness of the roll body of the roll, insufficient depth of an effective hardening layer, reduced wear resistance and the like.
In order to solve the problems, the invention provides novel YM5 series cold roll steel, which is prepared from the following raw materials in percentage by weight: c is 0.60-0.75%; si is 0.10-0.80%; mn is 0.20-0.90%; 4.5 to 5.5 percent of Cr; ni: less than or equal to 1.0 percent; mo is 1.00-2.0%; v is 0.10-1.00%; s is less than or equal to 0.015 percent; p is less than or equal to 0.015 percent; the balance being Fe.
Preferably, it is prepared by the following steps: electric furnace smelting or converter smelting, refining and vacuum treatment; electroslag remelting; high-temperature heat diffusion, multidirectional forging processing and cooling after forging; refining secondary carbides and carrying out isothermal spheroidizing annealing; rough machining and quenching and tempering heat treatment; performing semi-finishing and finish grinding on the roller body and performing ultrasonic flaw detection; carrying out high-temperature induction quenching on the roller body; carrying out subzero treatment at-80 to-100 ℃ immediately after quenching; tempering and heat preservation treatment at the temperature of 150-; fine processing; and (5) finishing the roller.
A preparation method of novel YM5 series cold roll steel comprises the following steps:
s10, smelting: carrying out batching electric furnace smelting or converter smelting, refining (LF) and vacuum treatment (VD) according to the chemical components and mass percentage of the novel cold rolling roller material, and then carrying out electroslag remelting;
s20, high-temperature diffusion heat treatment: heating at 1180-1300 deg.c for 10-25 hr;
s30, cooling the steel ingot subjected to high-temperature diffusion heat treatment to the temperature of 1000-1210 ℃ for multidirectional forging processing, wherein a three-upsetting and three-drawing forging mode is adopted, the total forging compression ratio is more than or equal to 8, and the final forging temperature is more than or equal to 950 ℃;
s40, cooling after forging: after forging, water cooling or mist cooling is adopted to ensure that the forging is rapidly cooled at a cooling speed of more than or equal to 0.1 ℃/s and then loaded into a heat treatment furnace;
s50, secondary carbide refining treatment: heating at 940-970 ℃, keeping the temperature for 5-15 hours, then cooling with water, and then loading into an annealing furnace for keeping the temperature at 300 ℃ for 5-15 hours;
s60, isothermal spheroidizing annealing: the first-stage isothermal annealing temperature is 820-850 ℃, and the heat preservation time is 10-25 hours; the isothermal annealing temperature of the second stage is 710-740 ℃, and the heat preservation time is 10-25 hours;
s70, hardening and tempering heat treatment: the quenching temperature is 950-970 ℃, the heat preservation time is 5-15 hours, and quenching liquid or oil is adopted to cool to below 200 ℃; then tempering at 580-680 ℃, and keeping the temperature for 10-20 hours;
s80, surface induction hardening: the surface is cooled by water after being heated to 960-980 ℃ by induction heating, then the subzero treatment of-50 to-100 ℃ is carried out, and finally the tempering is carried out at 150-.
Compared with the prior art, the invention has the following advantages:
1. the invention fully considers the working environment of the cold roll and the performance required by the cold roll, and effectively avoids the harm caused by the defects of alloy elements through the interaction between alloys on the basis of exerting the advantages of the alloy elements;
2. compared with 9Cr2Mo and 9Cr3Mo, the cold roll steel disclosed by the invention has the advantages that the carbon content is reduced, the content of primary carbides (namely liquation) is reduced, the peeling tendency of a roll body is reduced, the contents of Cr, Mo and V are improved, the hardenability and the deformation resistance of the material are improved, grains are refined, the tempering stability is improved, and the hardness and the wear resistance of the material are improved;
3. compared with MC5, the cold roll steel of the invention reduces the carbon content, the Cr content has no great difference, but the Mo content is improved, the same function as the above is achieved, simultaneously the C content is reduced, the heat treatment stress is reduced, the toughness is improved, the surface hardness of the prepared cold roll is 80-90HSD, and the cold roll steel has good crack extension resistance and higher substrate strength;
4. in the preparation method, harmful elements of steel are fully removed through electric furnace smelting or converter smelting, refining (LF), vacuum treatment (VD) and electroslag remelting; the primary carbide is eliminated by high-temperature diffusion heat treatment, so that the harm caused by the primary carbide is avoided; cooling after forging and refining the secondary carbide to ensure that the carbide is fine and dispersed, and the hardness is uniform after the finished product is prepared; the material obtains the best performance through the comprehensive action of the induction quenching, the cold treatment and the tempering process.
Drawings
FIG. 1 is a graph showing comparative tempering stability curves of example 1, example 2 and example 3 of the present invention and a comparative example;
FIG. 2 is a graphical representation of the hardenability comparison curves for examples 1, 2, 3 of the present invention and comparative examples;
FIG. 3 is a graph showing the abrasion resistance comparison curves of example 1, example 2, example 3 and a comparative example of the present invention;
FIG. 4 is a schematic view of the isothermal spheroidized annealed structure of the novel cold roll material of example 1 of the present invention;
FIG. 5 is a schematic view of the microstructure of the novel cold roll material of example 1 of the present invention;
FIG. 6 is a schematic view of the isothermal spheroidized annealed structure of the novel cold roll material of example 2 of the present invention;
FIG. 7 is a schematic view of the microstructure of the novel cold roll material of example 2 of the present invention;
FIG. 8 is a schematic view of the isothermal spheroidized annealed structure of the novel cold roll material of example 3 of the present invention;
FIG. 9 is a schematic view of the quenched and tempered microstructure of the novel cold-rolled material of example 3 of the present invention;
FIG. 10 is a schematic view of the 9Cr3Mo isothermal spheroidized annealed structure prepared by the comparative example conventional method of the present invention;
FIG. 11 is a schematic view of a quenched and tempered structure of 9Cr3Mo prepared by a conventional method according to a comparative example of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the accompanying drawings and examples, which are not intended to limit the present invention.
In the embodiment of the invention, the functions of each component are as follows:
1) the carbon can expand a gamma phase region, and the hardness and the strength of the steel are improved along with the increase of the content; the hardenability of the steel is improved. But because the carbon can not be infinitely dissolved, a primary cementite and a reticular secondary cementite are easily formed due to excessively high carbon content; the plasticity and the toughness are reduced and the Ms point is reduced with the increase of the content. Therefore, the amount of C in the present invention is 0.60 to 0.75%.
2) Silicon can improve the strength of solid solution in steel. Si is an effective element for improving the tempering resistance, and reduces the diffusion speed of carbon in ferrite, so that carbides precipitated by tempering are not easy to aggregate, and the tempering stability is improved; the high-temperature oxidation resistance of the steel is improved; too high a silicon content tends to cause the steel to exhibit a band-like structure, which deteriorates the transverse properties of the steel. Increasing the degree of carbon segregation and cold work hardening in the steel decreases the toughness and plasticity of the steel. Therefore, the Si content of the invention is 0.10-0.80%
3) Manganese can improve the hardenability of steel. Manganese and iron form a solid solution to improve the hardness and strength of ferrite and austenite in the steel, and Mn can form carbides to improve the strength, hardness and wear resistance of the steel. Manganese improves the high-temperature instantaneous strength of the steel. But when the manganese content is higher, the tempering brittleness phenomenon is more obvious; manganese has the function of promoting the growth of crystal grains, so that the manganese steel is sensitive to overheating and needs to be overcome by adding refined crystal grain elements such as molybdenum, vanadium, titanium and the like. Therefore, the Mn content of the invention is 0.20-0.90%, and a certain amount of V is added.
4) Chromium can improve the strength, hardness and hardenability of steel; the high-temperature mechanical property of the steel is improved. The steel has good corrosion resistance and oxidation resistance to prevent graphitization. Form carbide, raise wear resistance and raise tempering stability. Therefore, the amount of Cr in the present invention is 4.5 to 5.5%.
5) Nickel can improve the strength and hardenability of steel, improve the toughness of the steel and improve the fatigue resistance. The low-temperature toughness of the steel can be improved by reducing the brittle transition temperature of the steel. The nickel can improve the corrosion resistance of the steel, and can resist acid, alkali and atmosphere corrosion. Increases dendrite, improves transverse performance (8) and accelerates the diffusion of carbon in austenite, Ni is a non-carbide forming element, improves the diffusion coefficient of carbon in austenite, reduces primary carbide and ensures that secondary carbide is not easy to grow up. However, too high a nickel content increases the amount of retained austenite in the quenched steel, increasing the amount of deformation. Therefore, the invention has the following characteristics: less than or equal to 1.0 percent.
6) Molybdenum has a solid solution strengthening effect on ferrite. The hot strength of the steel is improved, the high-temperature strength is improved, and the sufficient strength and the creep resistance are kept at high temperature. The crystal grains are refined, and the high toughness and hardenability of the steel are improved. Form carbide, raise the antiwear performance, raise the tempering stability and inhibit the tempering brittleness of steel. The content of Mo in the invention is 1.00-2.0%.
7) Vanadium can improve the heat strength of steel, refine crystal grains, form carbide and improve the abrasion resistance. However, too high a vanadium content may form a large amount of poorly soluble primary carbides, thereby reducing toughness. Therefore, the V content of the present invention is 0.10 to 1.00%.
Example 1
The novel cold-rolling roller material in the embodiment comprises the following components in percentage by mass:
c is 0.60%; si is 0.10%; mn is 0.20%; 4.5 percent of Cr; ni is 0.1%; mo is 1.00 percent; v is 0.10%; s is 0.003%; p is 0.010%; the balance being Fe.
The novel cold roll produced by the components according to the proportion comprises the following technical processes:
(1) electric furnace smelting: according to the components and the mass percentage thereof in the embodiment, the electric furnace smelting temperature is more than 1500 ℃, the refining (LF) and the vacuum treatment (VD) are carried out, and the electrode blank with phi 330 to phi 380 is cast and annealed in parallel.
(2) Electroslag remelting: carrying out electroslag remelting on the electrode blank, wherein the slagging time is as follows: 20min current 3500A, refining 30min current 7000A. Remelting voltage: current of 73V: 8000A-13000A. Feeding voltage: and (3) carrying out mold cooling for 50 minutes at the current time of 61V for 40min, and annealing electroslag steel ingots.
(3) High-temperature diffusion heat treatment: heating the electroslag ingot subjected to electroslag remelting to 1180-1300 ℃ in multiple stages, preserving heat for 10-25 hours, homogenizing the structure, improving alloy composition segregation and eliminating liquated carbide.
(4) Forging and processing: the steel ingot after high-temperature diffusion heat treatment is cooled to 1000-1210 ℃ for multidirectional forging processing, a three-upsetting and three-drawing forging mode is adopted, the total forging compression ratio is more than or equal to 8, and the final forging temperature is more than or equal to 930 ℃.
(5) Cooling after forging: after forging, water cooling or mist cooling is adopted to ensure that the forging is rapidly cooled at a cooling speed of more than or equal to 0.1 ℃/s and then is loaded in a heat treatment furnace.
(6) Refining secondary carbides: the heating temperature is 940-970 ℃, the heat preservation time is 5-15 hours, and the post-annealing furnace is cooled with water and the heat preservation time is 5-15 hours at 300 ℃.
(7) Isothermal spheroidizing annealing treatment: the first-stage isothermal annealing temperature is 820-850 ℃, and the heat preservation time is 10-25 hours; the isothermal annealing temperature of the second stage is 710-740 ℃, and the heat preservation time is 10-25 hours.
(8) Quenching and tempering heat treatment: the quenching temperature is 950-970 ℃, the heat preservation time is 5-15 hours, and quenching liquid or oil is adopted to cool to below 200 ℃; then tempering at 580-680 ℃ for 10-20 hours
(9) Surface induction quenching: the surface is cooled by water after being heated to 960-980 ℃ by induction heating, then the subzero treatment of-50 to-100 ℃ is carried out, and finally the tempering is carried out at 150-.
After the novel cold-rolled roll material of the embodiment is subjected to the production process, the specification of the final finished roll body is phi 105 x 900, and a sample is taken for testing, and the result is as follows:
phase transformation point:
the Ac1, Ac3 and Ms points were measured at 830 deg.C, 950 deg.C and 220 deg.C.
Tempering property:
the characteristic curve of the temper hardness after quenching at 960 ℃ as a function of the tempering temperature is shown in FIG. 1, and it can be seen from FIG. 1 that the tempering stability of the steel for cold rolls of the present invention is superior to 9Cr3 Mo.
The hardness test in the range of 45mm from the surface to the surface is as follows, and the curve is as shown in figure 2:
as can be seen from FIG. 2, the hardenability of the steel for cold rolls of the present invention is superior to that of 9Cr3 Mo.
Abrasion test:
the loss of wear mass at each time condition measured under a load of 250N using an MM-200 type abrasion tester according to the GB12444.2.90 metal abrasion test method is shown in the following table, and the curve is shown in fig. 3:
wear time (hours) | 1 | 2 | 4 | 6 | 8 | 10 |
Loss of wear mass (mg) | 2 | 4 | 10 | 20 | 32 | 44 |
As can be seen from FIG. 3, the steel for cold rolls according to the present invention is superior in wear resistance to 9Cr3 Mo.
Microstructure:
the isothermal spheroidizing annealing structure of the novel cold-rolling roller material is shown in figure 4; the tone layer organization is shown in figure 5. The novel cold roll produced by the process has fine and uniform carbide distribution and does not contain primary carbide. The internal structure is obviously superior to that of a 9Cr3Mo roller prepared by a conventional method.
The hardness is 36-38 HRc:
yield strength: 1120N/mm2(ii) a Tensile strength: 1210N/mm2: room temperature (20 ℃) impact toughness AKV: 35J. Compared with 9Cr3Mo prepared by a conventional method, the yield strength and the tensile strength are not obviously different in the same hardness range, but the impact toughness is better than that of 9Cr3 Mo.
Comparative example
The 9Cr3Mo comprises the following components in percentage by mass:
c is 0.9%; si is 0.4%; mn is 0.30%; 3.0 percent of Cr; ni is 0.1%; mo is 0.3%; s is 0.010%; p is 0.010%; the balance being Fe.
The roll body of the final finished roll is prepared by a conventional method, the specification of the roll body of the final finished roll is phi 105 x 900, and a sample is taken for testing, and the result is as follows:
phase transformation point:
the Ac1, Ac3, and Ms points were measured as 790 ℃, 910 ℃, and 160 ℃.
Tempering property:
the characteristic curve of the temper hardness after quenching at 930 ℃ as a function of the tempering temperature is shown in FIG. 1.
The hardness test in the range of 45mm from the surface to the surface is as follows, and the curve is as shown in figure 2:
distance from surface (mm) | 0 | 1.5 | 3 | 6 | 9 | 12 | 15 | 20 | 25 | 30 | 35 | 40 | 45 |
Hardness (HRc) | 65 | 63 | 61 | 60 | 55 | 53 | 47 | 44 | 40 | 38 | 37 | 35 | 32 |
Abrasion test:
the loss of wear mass at each time condition measured under a load of 250N using an MM-200 type abrasion tester according to the GB12444.2.90 metal abrasion test method is shown in the following table, and the curve is shown in fig. 3:
wear time (hours) | 1 | 2 | 4 | 6 | 8 | 10 |
Loss of wear mass (mg) | 3 | 8 | 18 | 30 | 44 | 65 |
Microstructure:
the isothermal spheroidizing annealing structure of the novel cold-rolling roller material is shown in figure 10; the tone layer organization is shown in FIG. 11. It can be seen from fig. 10 and 11 that the 9Cr3Mo roll carbide prepared by the conventional method is coarse, unevenly distributed, and has significant primary carbides present.
The hardness is 36-38 HRc:
yield strength: 1100N/mm2(ii) a Tensile strength: 1230N/mm2(ii) a Room temperature (20 ℃) impact toughness AKV: 18J. Compared with the invention, within the same hardness range, the yield strength and the tensile strength are not obviously different, but the impact toughness is poorer.
Example 2
The novel cold-rolling roller material in the embodiment comprises the following components in percentage by mass:
c is 0.70%; si is 0.30%; mn is 0.40%; 5.0 percent of Cr; ni: 0.50 percent; mo is 1.50%; v is 0.50%; 0.002% of S and 0.009% of P; the balance being Fe.
The novel cold roll produced by the components according to the proportion comprises the following technical processes:
(1) electric furnace smelting: according to the components and the mass percentage thereof in the embodiment, the electric furnace smelting temperature is more than 1500 ℃, the refining (LF) and the vacuum treatment (VD) are carried out, and the electrode blank with phi 330 to phi 380 is cast and annealed in parallel.
(2) Electroslag remelting: carrying out electroslag remelting on the electrode blank, wherein the slagging time is as follows: 20min current 3500A, refining 30min current 7000A. Remelting voltage: current of 73V: 8000A-13000A. Feeding voltage: and (3) carrying out mold cooling for 50 minutes at the current time of 61V for 40min, and annealing electroslag steel ingots.
(3) High-temperature diffusion heat treatment: heating the electroslag ingot subjected to electroslag remelting to 1180-1300 ℃ in multiple stages, preserving heat for 10-25 hours, homogenizing the structure, improving alloy composition segregation and eliminating liquated carbide.
(4) Forging and processing: the steel ingot after high-temperature diffusion heat treatment is cooled to 1000-1210 ℃ for multidirectional forging processing, a three-upsetting and three-drawing forging mode is adopted, the total forging compression ratio is more than or equal to 8, and the final forging temperature is more than or equal to 930 ℃.
(5) Cooling after forging: after forging, water cooling or mist cooling is adopted to ensure that the forging is rapidly cooled at a cooling speed of more than or equal to 0.1 ℃/s and then is loaded in a heat treatment furnace.
(6) Refining secondary carbides: the heating temperature is 940-970 ℃, the heat preservation time is 5-15 hours, and the post-annealing furnace is cooled with water and the heat preservation time is 5-15 hours at 300 ℃.
(7) Isothermal spheroidizing annealing treatment: the first-stage isothermal annealing temperature is 820-850 ℃, and the heat preservation time is 10-25 hours; the isothermal annealing temperature of the second stage is 710-740 ℃, and the heat preservation time is 10-25 hours.
(8) Quenching and tempering heat treatment: the quenching temperature is 950-970 ℃, the heat preservation time is 5-15 hours, and quenching liquid or oil is adopted to cool to below 200 ℃; and then tempering at 580-680 ℃ for 10-20 hours.
(9) Surface induction quenching: the surface is cooled by water after being heated to 960-980 ℃ by induction heating, then the subzero treatment of-50 to-100 ℃ is carried out, and finally the tempering is carried out at 150-.
After the novel cold-rolled roll material of the embodiment is subjected to the production process, the specification of the final finished roll body is phi 105 x 900, and a sample is taken for testing, and the result is as follows:
phase transformation point:
the results of the tests for Ac1, Ac3, and Ms point were 835 deg.C, 955 deg.C, and 215 deg.C.
Tempering property:
the graph of the change of the temper hardness after 960 quenching according to the tempering temperature is shown in FIG. 1, and it can be seen from FIG. 1 that the temper stability of the steel for cold rolls of the present invention is superior to 9Cr3 Mo.
The hardness test in the range of 45mm from the surface to the surface is as follows, and the curve is as shown in figure 2:
as can be seen from FIG. 2, the hardenability of the steel for cold rolls of the present invention is superior to that of 9Cr3 Mo.
Abrasion test:
the loss of wear mass at each time condition measured under a load of 250N using an MM-200 type abrasion tester according to the GB12444.2.90 metal abrasion test method is shown in the following table, and the curve is shown in fig. 3:
wear time (hours) | 1 | 2 | 4 | 6 | 8 | 10 |
Loss of wear mass (mg) | 2 | 3 | 8 | 19 | 32 | 43 |
As can be seen from FIG. 3, the steel for cold rolls according to the present invention is superior in wear resistance to 9Cr3 Mo.
Microstructure:
the isothermal spheroidizing annealing structure of the novel cold-rolling roller material is shown in figure 6; the tone layer organization is shown in figure 7. The novel cold roll produced by the process has fine and uniform carbide distribution and does not contain primary carbide. The internal structure is obviously superior to that of a 9Cr3Mo roller prepared by a conventional method.
The hardness is 36-38 HRc:
yield strength: 1140N/mm2(ii) a Tensile strength: 1220N/mm2(ii) a Room temperature (20 ℃) impact toughness AKV: 32J. Compared with 9Cr3Mo prepared by a conventional method, the yield strength and the tensile strength are not obviously different in the same hardness range, but the impact toughness is better than that of 9Cr3 Mo.
Comparative example
The 9Cr3Mo comprises the following components in percentage by mass:
c is 0.9%; si is 0.4%; mn is 0.30%; 3.0 percent of Cr; ni is 0.1%; mo is 0.3%; s is 0.010%; p is 0.010%; the balance being Fe.
The roll body of the final finished roll is prepared by a conventional method, the specification of the roll body of the final finished roll is phi 105 x 900, and a sample is taken for testing, and the result is as follows:
phase transformation point:
the Ac1, Ac3, and Ms points were measured as 790 ℃, 910 ℃, and 160 ℃.
Tempering property:
the characteristic curve of the temper hardness after quenching at 930 ℃ as a function of the tempering temperature is shown in FIG. 1.
The hardness test in the range of 45mm from the surface to the surface is as follows, and the curve is as shown in figure 2:
distance from surface (mm) | 0 | 1.5 | 3 | 6 | 9 | 12 | 15 | 20 | 25 | 30 | 35 | 40 | 45 |
Hardness (HRc) | 65 | 63 | 61 | 60 | 55 | 53 | 47 | 44 | 40 | 38 | 37 | 35 | 32 |
Abrasion test:
the loss of wear mass at each time condition measured under a load of 250N using an MM-200 type abrasion tester according to the GB12444.2.90 metal abrasion test method is shown in the following table, and the curve is shown in fig. 3:
wear time (hours) | 1 | 2 | 4 | 6 | 8 | 10 |
Loss of wear mass (mg) | 3 | 8 | 18 | 30 | 44 | 65 |
Microstructure:
the isothermal spheroidizing annealing structure of the novel cold-rolling roller material is shown in figure 10; the tone layer organization is shown in FIG. 11. It can be seen from fig. 10 and 11 that the 9Cr3Mo roll carbide prepared by the conventional method is coarse, unevenly distributed, and has significant primary carbides present.
The hardness is 36-38 HRc:
yield strength: 1100N/mm2(ii) a Tensile strength: 1230N/mm2(ii) a Room temperature (20 ℃) impact toughness AKV: 18J. Compared with the invention, within the same hardness range, the yield strength and the tensile strength are not obviously different, but the impact toughness is poorer.
Example 3
The novel cold-rolling roller material in the embodiment comprises the following components in percentage by mass:
c is 0.75%; si is 0.80%; mn is 0.90%; 5.5 percent of Cr; ni is 1.0%; mo is 2.0%; v is 1.00%; s is 0.002%; p is 0.010%; the balance being Fe.
The novel cold roll produced by the components according to the proportion comprises the following technical processes:
(1) electric furnace smelting: according to the components and the mass percentage thereof in the embodiment, the electric furnace smelting temperature is more than 1500 ℃, the refining (LF) and the vacuum treatment (VD) are carried out, and the electrode blank with phi 330 to phi 380 is cast and annealed in parallel.
(2) Electroslag remelting: carrying out electroslag remelting on the electrode blank, wherein the slagging time is as follows: 20min current 3500A, refining 30min current 7000A. Remelting voltage: current of 73V: 8000A-13000A. Feeding voltage: and (3) carrying out mold cooling for 50 minutes at the current time of 61V for 40min, and annealing electroslag steel ingots.
(3) High-temperature diffusion heat treatment: heating the electroslag ingot subjected to electroslag remelting to 1180-1300 ℃ in multiple stages, preserving heat for 10-25 hours, homogenizing the structure, improving alloy composition segregation and eliminating liquated carbide.
(4) Forging and processing: the steel ingot after high-temperature diffusion heat treatment is cooled to 1000-1210 ℃ for multidirectional forging processing, a three-upsetting and three-drawing forging mode is adopted, the total forging compression ratio is more than or equal to 8, and the final forging temperature is more than or equal to 930 ℃.
(5) Cooling after forging: after forging, water cooling or mist cooling is adopted to ensure that the forging is rapidly cooled at a cooling speed of more than or equal to 0.1 ℃/s and then is loaded in a heat treatment furnace.
(6) Refining secondary carbides: the heating temperature is 940-970 ℃, the heat preservation time is 5-15 hours, and the post-annealing furnace is cooled with water and the heat preservation time is 5-15 hours at 300 ℃.
(7) Isothermal spheroidizing annealing treatment: the first-stage isothermal annealing temperature is 820-850 ℃, and the heat preservation time is 10-25 hours; the isothermal annealing temperature of the second stage is 710-740 ℃, and the heat preservation time is 10-25 hours.
(8) Quenching and tempering heat treatment: the quenching temperature is 950-970 ℃, the heat preservation time is 5-15 hours, and quenching liquid or oil is adopted to cool to below 200 ℃; and then tempering at 580-680 ℃ for 10-20 hours.
(9) Surface induction quenching: the surface is cooled by water after being heated to 960-980 ℃ by induction heating, then the subzero treatment of-50 to-100 ℃ is carried out, and finally the tempering is carried out at 150-.
After the novel cold-rolled roll material of the embodiment is subjected to the production process, the specification of the final finished roll body is phi 105 x 900, and a sample is taken for testing, and the result is as follows:
phase transformation point:
the Ac1, Ac3 and Ms points were measured at 842 deg.C, 960 deg.C and 208 deg.C.
Tempering property:
the characteristic curve of the temper hardness after quenching at 960 ℃ as a function of the tempering temperature is shown in FIG. 1, and it can be seen from FIG. 1 that the tempering stability of the steel for cold rolls of the present invention is superior to 9Cr3 Mo.
The hardness test in the range of 45mm from the surface to the surface is as follows, and the curve is as shown in figure 2:
as can be seen from FIG. 2, the hardenability of the steel for cold rolls of the present invention is superior to that of 9Cr3 Mo.
Abrasion test:
the loss of wear mass at each time condition measured under a load of 250N using an MM-200 type abrasion tester according to the GB12444.2.90 metal abrasion test method is shown in the following table, and the curve is shown in fig. 3:
wear time (hours) | 1 | 2 | 4 | 6 | 8 | 10 |
Loss of wear mass (mg) | 1 | 2 | 7 | 16 | 26 | 40 |
As can be seen from FIG. 3, the steel for cold rolls according to the present invention is superior in wear resistance to 9Cr3 Mo.
Microstructure:
the isothermal spheroidizing annealing structure of the novel cold-rolling roller material is shown in figure 8; the tone layer organization is shown in figure 9. The novel cold roll produced by the process has fine and uniform carbide distribution and does not contain primary carbide. The internal structure is obviously superior to that of a 9Cr3Mo roller prepared by a conventional method.
The hardness is 36-38 HRc:
yield strength: 1140N/mm2(ii) a Tensile strength: 1230N/mm2(ii) a Room temperature (20 ℃) impact toughness AKV: 30J. Compared with 9Cr3Mo prepared by a conventional method, the yield strength and the tensile strength are not obviously different in the same hardness range, but the impact toughness is better than that of 9Cr3 Mo.
Comparative example
The 9Cr3Mo comprises the following components in percentage by mass:
c is 0.9%; si is 0.4%; mn is 0.30%; 3.0 percent of Cr; ni is 0.1%; mo is 0.3%; s is 0.010%; p is 0.010%; the balance being Fe.
The roll body of the final finished roll is prepared by a conventional method, the specification of the roll body of the final finished roll is phi 105 x 900, and a sample is taken for testing, and the result is as follows:
phase transformation point:
the Ac1, Ac3, and Ms points were measured as 790 ℃, 910 ℃, and 160 ℃.
Tempering property:
the characteristic curve of the temper hardness after quenching at 930 ℃ as a function of the tempering temperature is shown in FIG. 1.
The hardness test in the range of 45mm from the surface to the surface is as follows, and the curve is as shown in figure 2:
distance from surface (mm) | 0 | 1.5 | 3 | 6 | 9 | 12 | 15 | 20 | 25 | 30 | 35 | 40 | 45 |
Hardness (HRc) | 65 | 63 | 61 | 60 | 55 | 53 | 47 | 44 | 40 | 38 | 37 | 35 | 32 |
Abrasion test:
the loss of wear mass at each time condition measured under a load of 250N using an MM-200 type abrasion tester according to the GB12444.2.90 metal abrasion test method is shown in the following table, and the curve is shown in fig. 3:
wear time (hours) | 1 | 2 | 4 | 6 | 8 | 10 |
Loss of wear mass (mg) | 3 | 8 | 18 | 30 | 44 | 65 |
Microstructure:
the isothermal spheroidizing annealing structure of the novel cold-rolling roller material is shown in figure 10; the tone layer organization is shown in FIG. 11. It can be seen from fig. 10 and 11 that the 9Cr3Mo roll carbide prepared by the conventional method is coarse, unevenly distributed, and has significant primary carbides present.
The hardness is 36-38 HRc:
yield strength: 1100N/mm2(ii) a Tensile strength: 1230N/mm2(ii) a Room temperature (20 ℃) impact toughness AKV: 18J. Compared with the invention, within the same hardness range, the yield strength and the tensile strength are not obviously different, but the impact toughness is poorer.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (3)
1. The novel YM5 series cold roll steel is characterized by being prepared from the following raw materials in percentage by weight: c is 0.60-0.75%; si is 0.10-0.80%; mn is 0.20-0.90%; 4.5 to 5.5 percent of Cr; ni: less than or equal to 1.0 percent; mo is 1.00-2.0%; v is 0.10-1.00%; s is less than or equal to 0.015 percent; p is less than or equal to 0.015 percent; the balance being Fe.
2. The novel YM5 series cold roll steel according to claim 1, prepared by: electric furnace smelting or converter smelting, refining and vacuum treatment; electroslag remelting; high-temperature heat diffusion, multidirectional forging processing and cooling after forging; refining secondary carbides and carrying out isothermal spheroidizing annealing; rough machining and quenching and tempering heat treatment; performing semi-finishing and finish grinding on the roller body and performing ultrasonic flaw detection; carrying out high-temperature induction quenching on the roller body; carrying out subzero treatment at-80 to-100 ℃ immediately after quenching; and (4) tempering and heat preservation treatment at the temperature of 150-200 ℃ is carried out on the roller after the cold treatment. Fine processing; and (5) finishing the roller.
3. A method for manufacturing a novel YM5 series cold roll steel according to claim 1, comprising the steps of:
s10, smelting: carrying out batching electric furnace smelting or converter smelting, refining (LF) and vacuum treatment (VD) according to the chemical components and mass percentage of the novel cold rolling roller material, and then carrying out electroslag remelting;
s20, high-temperature diffusion heat treatment: heating at 1180-1300 deg.c for 10-25 hr;
s30, cooling the steel ingot subjected to high-temperature diffusion heat treatment to the temperature of 1000-1210 ℃ for multidirectional forging processing, wherein a three-upsetting and three-drawing forging mode is adopted, the total forging compression ratio is more than or equal to 8, and the final forging temperature is more than or equal to 950 ℃;
s40, cooling after forging: after forging, water cooling or mist cooling is adopted to ensure that the forging is rapidly cooled at a cooling speed of more than or equal to 0.1 ℃/s and then loaded into a heat treatment furnace;
s50, secondary carbide refining treatment: heating at 940-970 ℃, keeping the temperature for 5-15 hours, then cooling with water, and then loading into an annealing furnace for keeping the temperature at 300 ℃ for 5-15 hours;
s60, isothermal spheroidizing annealing: the first-stage isothermal annealing temperature is 820-850 ℃, and the heat preservation time is 10-25 hours; the isothermal annealing temperature of the second stage is 710-740 ℃, and the heat preservation time is 10-25 hours;
s70, hardening and tempering heat treatment: the quenching temperature is 950-970 ℃, the heat preservation time is 5-15 hours, and quenching liquid or oil is adopted to cool to below 200 ℃; then tempering at 580-680 ℃, and keeping the temperature for 10-20 hours;
s80, surface induction hardening: the surface is cooled by water after being heated to 960-980 ℃ by induction heating, then the subzero treatment of-50 to-100 ℃ is carried out, and finally the tempering is carried out at 150-.
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CN109554612A (en) * | 2018-12-10 | 2019-04-02 | 宜兴市永昌轧辊有限公司 | A kind of novel cold rolling working roll and preparation method thereof |
CN114635089A (en) * | 2022-03-22 | 2022-06-17 | 河北恒韧增材制造有限公司 | Easily-processed high-strength high-toughness high-wear-resistance nitride alloy roller |
EP4365119A4 (en) * | 2022-09-22 | 2024-08-21 | Jiangsu Contemporary Amperex Tech Ltd | Back roller, preparation method therefor, and coating machine |
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