CN112501512A - Controlled rolling and controlled cooling high-strength pearlitic steel rail and production method thereof - Google Patents
Controlled rolling and controlled cooling high-strength pearlitic steel rail and production method thereof Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
- B21B37/74—Temperature control, e.g. by cooling or heating the rolls or the product
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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
- C21D11/00—Process control or regulation for heat treatments
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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
- C21D9/04—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for rails
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium with vanadium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
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Abstract
The invention discloses a controlled rolling and cooling pearlite steel rail with high strength and a production method thereof, wherein the steel rail comprises the chemical components of 0.71-0.85% of C, 0.45-0.70% of Si, 0.35-0.70% of Mn, 0.2-1.0% of Cr, 0.05-0.1% of V, 0.005-0.08% of Nb, 0-0.025% of P, 0-0.015% of S and the balance of Fe and inevitable impurities according to mass fraction; the tensile strength of the steel rail is more than or equal to 1360MPa, the elongation is more than or equal to 12%, the tread hardness of the rail head is more than or equal to 390HB, the depth of a hardened layer is more than or equal to 30mm, the structure is fine lamellar pearlite, and the space between pearlite lamellae at the position which is 30mm away from the surface of the steel rail is less than or equal to 90 nm. The invention can improve the strength and hardness of the steel rail and keep good toughness and plasticity.
Description
Technical Field
The invention relates to a controlled rolling and cooling pearlite steel rail with good wear resistance and fatigue damage resistance and high strength and a production method thereof, belonging to the field of steel rail production and application.
Background
With the increase of the axle weight of the railway train, the running speed and the annual total passing mass of the railway are continuously increased, particularly in heavy-duty freight railways, the weight of vehicles borne by the steel rail is far greater than that of passenger railways, and the service environment of the steel rail also becomes more severe. Under such service conditions, the problems of abrasion and fatigue damage of the steel rail are becoming more serious, and thus the strength and hardness of the steel rail are required to be continuously improved to improve the wear resistance and fatigue damage resistance.
Steel rail manufacturers at home and abroad generally increase the contents of C, Si and Mn elements in steel rail steel, add alloy strengthening elements such as V, Cr and the like, and carry out an accelerated cooling process by using water mist mixed gas, compressed air and other media by utilizing the waste heat after steel rail rolling to ensure that the rail head part of the steel rail obtains a fine pearlite structure, so that the steel rail has high wear resistance and high hardness.
Patent 1 "pearlite rail with high internal hardness and excellent wear resistance and fatigue damage resistance and method for producing the same" (CN101646795A) provides a pearlite rail with high internal hardness and high hardness, which comprises, as chemical components, 0.73 to 0.85 mass% of C, 0.50 to 0.75 mass% of Si, 0.30 to 1.0 mass% of Mn, 0.035 mass% or less of P, 0.0005 to 0.012 mass% of S, 0.2 to 1.3 mass% of Cr, and the balance Fe and inevitable impurities. The steel rail finishing temperature is 850-950 ℃, then the steel rail is rapidly cooled from the temperature above the pearlite transformation starting temperature to 400-650 ℃ at the cooling speed of 1.2-5 ℃/s, and the Vickers hardness of the steel rail head surface layer to the depth range of at least 25mm is obtained to be HV380-HV 480.
Patent 2 "high-strength pearlitic rail excellent in delayed fracture resistance" (CN101405419A) provides a high-strength pearlitic rail having a tensile strength of 1200MPa or more and excellent in delayed fracture resistance. The steel rail comprises 0.6-1.0 mass% of C, 0.10-1.5 mass% of Si, 0.40-2.0 mass% of Mn, less than 0.035 mass% of P, 0.0005-0.012 mass% of S, and further comprises a component selected from V: 0.5% or less, Cr: 1.5% or less, Cu: 1% or less, Ni: 1% or less, Nb: 0.05% or less, Mo: 0.5% or less, W: 1% or less, or 1 or 2 or more, and the balance of Fe and inevitable impurities. Ca: more than 0.001%, less than 0.01%, O: 0.002% or less, H: 2ppm or less. The tensile strength of the rail is above 1200MPa, the long side dimension of the A-type inclusion on the section of the rail head part along the length direction is below 250 mu m, and each 1mm2The number of occurrences on the detected area is less than 25.
Patent 3 "method and apparatus for manufacturing heat-treated rail" (CN106661651B) provides a method and apparatus for manufacturing heat-treated rail having excellent hardness and toughness of the head surface layer by adding various alloy elements. The steel rail comprises 0.75-0.85 mass% of C, 0.5-1.0 mass% of Si, 0.5-1.0 mass% of Mn, 0.5-1.0 mass% of Cr, 0-0.01 mass% of V, and the balance of Fe and inevitable impurities. The steel rail head is cooled at a cooling rate of-5 ℃/s to 5 ℃/s before the completion of the phase change of the pearlite phase after the steel rail surface is forcibly cooled at a cooling rate of 10 ℃/s to 700 ℃ before the temperature of the steel rail surface is 500 ℃ to 700 ℃.
Patent 4 "heat treatment method and apparatus for producing high-strength steel rail by using rolling waste heat" (CN1083013C) provides a heat treatment method for producing high-strength steel rail by using rolling waste heat. The steel rail comprises 0.65-0.85 mass% of C, 0.21-1.2 mass% of Si, 0.50-1.5 mass% of Mn and at least one of V, Cr, Ti, Mo, Cu, Ni and rare earth elements. The rail kept in the high temperature state in the austenite region after hot rolling is continuously fed into a unit equipped with a heat treatment device, and a cooling medium is sprayed to the rail through a nozzle to uniformly accelerate cooling of the rail, thereby obtaining a fine pearlite structure with gradually reduced hardness.
Patent 5 "pearlite heat-treated steel rail and production method thereof" (CN 1793403 a) provides a pearlite heat-treated steel rail and production method thereof. The steel rail comprises 0.70-0.95 mass% of C, 0.20-1.10 mass% of Si, 0.5-1.50 mass% of Mn, 0.01-0.20 mass% of V, 0.15-1.20 mass% of Cr, less than 0.035 mass% of P, less than 0.035 mass% of S and less than 0.005 mass% of Al. The production method comprises smelting, rolling and heat treatment, the steel rail is cooled to 400-500 ℃ at the cooling speed of 1-10 ℃/s from 650-880 ℃, and then is naturally cooled to room temperature, the tensile strength of the produced steel rail head is more than 1310MPa, the hardness of the rail head is more than 370HB, the depth of a hardened layer reaches more than 20mm, and the steel rail has good wear resistance.
Patent 6 "high carbon high strength heat treated rail with excellent wear resistance and plasticity and manufacturing method thereof" (CN102220545A) provides a high carbon high strength heat treated rail with excellent wear resistance and plasticity and production method thereof. The steel rail comprises 0.80-1.20 mass% of C, 0.20-1.20 mass% of Si, 0.20-1.60 mass% of Mn, 0.01-0.20 mass% of V, 0.15-1.20 mass% of Cr, 0.002-0.050 mass% of Ti, less than 0.030 mass% of P, less than 0.030 mass% of S, less than 0.010 mass% of Al, less than 0.010 mass% of N, and the balance of iron and inevitable impurities. The production process comprises the steps of keeping the hot steel rail at the temperature of 680-900 ℃ after rolling, cooling the steel rail to 500 ℃ at the cooling speed of 1.5-10 ℃/s, and naturally cooling to room temperature, wherein the tensile strength of the steel rail is not less than 1330MPa, the elongation is not less than 9%, the hardness of a rail head is not less than 380HB, the depth of a hardened layer is more than 25mm, and the structure is fine pearlite.
The steel rail is used as a section steel product, and because a rolling pass system and a rolling schedule are basically fixed, the deformation rate is basically constant, the adjustable range of the rolling temperature is narrow, and the traditional process thought considers that the control rolling of the steel rail is difficult to realize. Therefore, the above patents only consider controlling the cooling process after rolling the steel rail, and the better hardness improvement effect cannot be obtained in the cooling speed range under the condition of increasing the addition amount of the alloy elements.
Therefore, a controlled rolling process for regulating and controlling recrystallization behavior in the rolling process is needed, and a high-strength pearlitic steel rail and a production method thereof are combined with a controlled cooling process after rolling, so that the strength and hardness of the steel rail are further improved, and good elongation after fracture is kept.
Disclosure of Invention
Based on the problem that the strength and hardness of the pearlitic steel rail are difficult to further improve due to insufficient regulation and control of rolling recrystallization behavior in the production of the high-strength heat-treated steel rail in the prior art, the invention provides the controlled-rolling controlled-cooling high-strength steel rail and the production method thereof.
In order to solve the technical problems, the invention provides a rolling-control cooling-control high-strength pearlitic steel rail, which comprises the following chemical components, by mass, 0.71-0.85% of C, 0.45-0.70% of Si, 0.35-0.70% of Mn, 0.2-1.0% of Cr, 0.05-0.1% of V, 0.005-0.08% of Nb, 0-0.025% of P, 0-0.015% of S, and the balance of Fe and inevitable impurities.
Preferably, the controlled rolling and cooling controlled high strength pearlitic steel rail provided by the invention further comprises part or all of the following technical characteristics:
as an improvement of the technical scheme, the tensile strength of the steel rail is more than or equal to 1360MPa, the elongation is more than or equal to 12%, the tread hardness of the rail head is more than or equal to 390HB, the depth of a hardened layer is more than or equal to 30mm, the structure is fine lamellar pearlite, and the space between pearlite lamellae at the position which is 30mm away from the surface of the steel rail is less than or equal to 90 nm.
A method for producing the controlled rolling and cooling high-strength pearlitic steel rail comprises the following steps: the heating temperature is controlled to be 1160-1200 ℃, and the heating time is controlled to be 140-200 min; the initial rolling temperature is 1050-; after the steel rail is rolled, carrying out online accelerated cooling treatment on the rail head and the rail bottom of the steel rail after hot rolling, wherein the starting cooling temperature is controlled to be 680 ℃ or above, the cooling speed of the rail head is 1.0-5.0 ℃/s, the cooling speed of the rail bottom is 0.5-2.0 ℃/s, and after the temperature of the rail head is reduced to 400-500 ℃; stopping accelerated cooling, and naturally cooling to room temperature;
the steel rail production method further comprises the following steps: converter smelting, LF refining, vacuum treatment and continuous casting, wherein the procedures are not particularly limited and can be carried out according to a conventional steel rail production process method.
Preferably, the method for producing the controlled rolling and cooling high-strength pearlitic steel rail further comprises the following technical characteristics in part or all:
as an improvement of the technical scheme, the chemical components of the steel rail comprise, by mass, 0.71-0.85% of C, 0.45-0.70% of Si, 0.35-0.70% of Mn, 0.2-1.0% of Cr, 0.05-0.1% of V, 0.005-0.08% of Nb, 0-0.025% of P, 0-0.015% of S, and the balance of Fe and inevitable impurities.
As an improvement of the technical scheme, the chemical components of the steel rail comprise, by mass, 0.73-0.83% of C, 0.50-0.65% of Si, 0.40-0.65% of Mn, 0.4-0.8% of Cr, 0.06-0.08% of V, 0.01-0.04% of Nb, 0-0.025% of P, 0-0.015% of S, and the balance of Fe and inevitable impurities.
As an improvement of the technical scheme, the heating temperature is controlled to 1170-1200 ℃, and the heating time is controlled to 160-180 min; the initial rolling temperature is 1080-.
After the steel rail is rolled, performing online accelerated cooling treatment on the hot-rolled steel rail, controlling the starting cooling temperature to be 680 ℃ or more, controlling the cooling speed of the rail head to be 2.0-4.0 ℃/s, controlling the cooling speed of the rail bottom to be 0.8-1.5 ℃/s, and cooling the rail head to be 420-480 ℃; stopping accelerated cooling, and naturally cooling to room temperature.
As an improvement of the technical scheme, the rail head temperature refers to the temperature in centigrade of the surface of the central part of the tread of the rail head.
As a modification of the above technical solution, the accelerated cooling medium is a cooling medium commonly used in the art, and includes, but is not limited to, water, polymer solution, oil, compressed air, water mist, or oil mist mixture.
The rail head, rail foot, tread, etc. of the rail of the present invention are the positions conventionally referred to in the art and are well known to those skilled in the art.
The reasons for selecting the technical parameters are as follows: 1) c is the most basic and cheapest reinforcing element for improving the strength and hardness of the rail, and is a main element forming pearlite and carbide, and generally, as the content of C in steel increases, the strength and hardness of the steel increase, and the plasticity and toughness decrease. When the components are actually designed, the content range of C is determined according to specific technical requirements, the content of C is too low, the density of lamellar cementite in a pearlite structure cannot be ensured, the basic strength and hardness of the steel rail are insufficient, and the using effect is influenced; since too high a content of C causes a decrease in toughness and plasticity and a decrease in weldability, the present invention controls the content of C to be in the range of 0.71 to 0.85 wt%. 2) Si can inhibit cementite in the steel from forming and promote ferrite transformation, and the Si plays a role in solid solution strengthening by being dissolved in ferrite, so that the hardness of a ferrite matrix is improved, the strength and the hardness of the steel are improved, the Si can improve the Acm temperature of the steel, the supercooling degree is improved, and the phase change driving force of pearlite in the accelerated cooling process is increased. When the Si content in the steel is more than 0.7%, local segregation is liable to occur and the weldability of the rail is deteriorated, so that the Si content is controlled within the range of 0.45 to 0.70% by weight. 3) Mn has a solid solution strengthening effect on ferrite, can improve the ferrite strength, is also a carbide forming element, can partially replace Fe atoms after entering cementite, improves the strength and the hardness of steel, and simultaneously can reduce the pearlite phase transition temperature of the steel and reduce the interlayer spacing of pearlite sheets; however, Mn can lower the Acm temperature of steel, and influences the driving force for accelerating the phase change process of the cooling process, and the content range of Mn needs to be controlled. Therefore, the Mn content is controlled to be in the range of 0.35 to 0.70 wt%. 4) Cr can form a replacement solid solution with alpha-Fe to play a role in solid solution strengthening, and meanwhile, Cr is a strong carbide forming element, so that the C curve of the steel is shifted to the right, the strength and the hardenability of the steel rail can be obviously improved, the hardness of the steel rail after heat treatment is obviously improved, but the increase of the Cr content can reduce the plasticity and the toughness of the steel, and the Cr content is controlled within the range of 0.2-1.0 weight percent. 5) V is a precipitation strengthening element, and is combined with C, N in the cooling process of the hot-rolled steel rail to form V (CN) x precipitate, so that the strength and the hardness of the steel rail are improved, and simultaneously, the growth of crystal grains is prevented and austenite crystal grains are refined in the welding and heating process of the steel rail. The solubility of V at room temperature is very low, and generally, when the content of V is about 0.1%, the precipitation strengthening effect is obvious, and when the content of V is increased, the strength and hardness of the steel rail are further increased, the toughness can be greatly reduced, and when the content of V is too low, the strengthening effect of a precipitated phase is not obvious. Therefore, the V content is controlled to be in the range of 0.05 to 0.1% by weight. 6) Nb can inhibit austenite grains from growing large, improve the critical austenitizing temperature, improve the upper limit of the temperature of a non-recrystallization zone, promote the accumulation of rolling deformation of an austenite zone, refine austenite grains, and simultaneously play a role in refining pearlite interlamellar spacing by matching with control cooling, but the high-temperature thermoplasticity of steel can be reduced by the over-high Nb content, and billet hot cracking is easily caused, so the Nb content is controlled within the range of 0.005-0.08 percent by weight. 7) For steel rails, P, S is generally regarded as a harmful residual element in steel, which can greatly increase the crack sensitivity of steel, increase the low-temperature brittle transition temperature of steel, and reduce the low-temperature impact property of steel, so that the lower the P, S content is, the better the steel rail performance is not affected. 8) The heating temperature of the steel rail is controlled to be 1160-1200 ℃, and the heating time is controlled to be 140-200 min. The austenitizing temperature is not suitable to be too high so as to avoid the excessive growth of austenite grains, but the heating temperature is too low so as to increase the load of the rolling mill, and meanwhile, in order to ensure that alloy elements are dissolved in austenite, the heating temperature is not too low, and reasonable heating temperature and time are selected according to specific conditions. 9) The initial rolling temperature of the steel rail is 1050-. Rolling at a relatively low temperature to inhibit dynamic recrystallization in the rolling process and promote the accumulation of rolling deformation of an austenite region, wherein high dislocation density and deformation subgrains still exist in austenite grains after the deformation is stopped, and static recovery and static recrystallization can continue to occur, so that refined austenite grains are finally obtained. 10) After the steel rail is rolled, carrying out online accelerated cooling treatment on the rail head and the rail bottom of the steel rail after hot rolling, controlling the starting cooling temperature to be more than 680 ℃, controlling the cooling speed of the rail head to be 1.0-5.0 ℃/s and the cooling speed of the rail bottom to be 0.5-2.0 ℃/s, and after the temperature of the rail head is reduced to 400-500 ℃; stopping accelerated cooling, and naturally cooling to room temperature. The steel rail after rolling is subjected to accelerated cooling, and the supercooling degree of austenite transformed to pearlite is increased, so that pearlite with finer lamella spacing is obtained, and the hardness and strength of the steel rail are improved. Simultaneously in railhead accelerated cooling, also exert relatively less cooling rate to the railhead bottom of a rail, this is because railhead cooling rate is very fast, if the railhead bottom of a rail natural cooling, railhead bottom of a rail temperature difference is too big can cause the rail to bend by a wide margin, in order to guarantee heat treatment in-process rail straightness, generally also exert certain cooling rate to the railhead bottom of a rail, and the railhead is less than to the railhead bottom metal volume, and the cooling rate generally also needs to be less than the railhead, keeps the temperature uniformity of railhead bottom of a rail as far as possible.
Compared with the prior art, the technical scheme of the invention has the following beneficial effects: the invention provides a rolling-controlled and cooling-controlled high-strength pearlite steel rail and a production method thereof. The tensile strength of the steel rail is more than or equal to 1360MPa, the elongation is more than or equal to 12%, the tread hardness of the rail head is more than or equal to 390HB, the depth of a hardened layer is more than or equal to 30mm, the structure is fine lamellar pearlite, the spacing between pearlite lamellae at the position which is 30mm away from the surface of the steel rail is less than or equal to 90nm, the steel rail has good wear resistance and fatigue damage resistance, and the production method is simple, strong in operability and easy to popularize and apply.
The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly understood, the present invention may be implemented in accordance with the contents of the description, and in order to make the above and other objects, features, and advantages of the present invention more clearly understood, the following detailed description is given in conjunction with the preferred embodiments.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments will be briefly described below.
FIG. 1 is a schematic view of a rolling contact wear test of a steel rail according to the present invention; wherein fig. 1(a) is a front view and fig. 1(b) is a side view;
FIG. 2 shows the interlayer spacing of pearlite plates for rolling-controlled cooling-controlled high-strength steel rail.
Detailed Description
Other aspects, features and advantages of the present invention will become apparent from the following detailed description, which, when taken in conjunction with the drawings, illustrate by way of example the principles of the invention.
The metallurgical chemical compositions of examples 1 to 4 of the present invention are shown in Table 1.
TABLE 1 chemical composition of the examples
Example 1:
the method is carried out according to the conventional steel rail smelting and casting method, and the working procedures comprise converter smelting, LF refining, vacuum treatment and continuous casting. Wherein, the alkalinity of the converter slag is controlled to be 2.5-3.8; when molten steel is discharged about 1/4, alloy such as silicon, manganese, vanadium and the like and carburant are added along with the steel flow, and when the molten steel is discharged to 3/4, the alloy and the carburant are all added; the treatment time of the LF furnace is more than 40 min; RH vacuum degree is less than or equal to 90Pa, pure vacuum treatment time is not less than 20min, casting process is carried out under protection of the whole process to prevent contact with air, and cast steel billet is slowly cooled. And (2) feeding the steel billet into a walking beam heating furnace for heating and heat preservation, wherein the heating temperature is 1170 ℃, the heat preservation time is 160min, rolling the steel billet into a steel rail by using a universal rolling mill, the initial rolling temperature is 1060 ℃, the final rolling temperature is 860 ℃, carrying out online accelerated cooling treatment on the rail head and the rail bottom of the steel rail after hot rolling, controlling the initial cooling temperature to be 720 ℃, the cooling speed of the rail head to be 2 ℃/s, the cooling speed of the rail bottom to be 1 ℃/s, stopping accelerated cooling after the temperature of the rail head is reduced to 420 ℃, naturally cooling to room temperature, and finally straightening the steel rail by adopting a vertical composite straightening process.
Examples 2 to 4:
the procedure is as in example 1, except that the heating, rolling and heat treatment process parameters are as shown in Table 2.
TABLE 2 accelerated Cooling Process parameters of examples and comparative examples
The comparative example selects the most mature U75V online heat treatment product with the widest application range in the current industry, and the performance indexes of the tensile strength, tread hardness, elongation after fracture, metallographic structure, cross section Rockwell hardness, fracture toughness and the like of the steel rail obtained in the example and the comparative example are tested according to the method specified by TB/T2344-.
TABLE 3 Performance of the examples and comparative examples
It can be seen that the strength and hardness of the steel rails obtained in examples 1-4 are superior to those of the steel rail subjected to on-line heat treatment of U75V, the steel rail has better toughness and plasticity, and the metallographic structure is fine pearlite.
In order to verify that the steel rail obtained by the invention has better wear resistance and contact fatigue resistance compared with the steel rail subjected to on-line heat treatment by U75V, an M-2000 type rolling contact wear tester is adopted to carry out a contact fatigue wear test on the steel rails of the examples and the comparative examples under the same test conditions. The test is carried out by rolling the cylindrical samples relatively, measuring the abrasion weight loss and observing the fatigue crack condition of the surfaces of the samples, and the test schematic diagram is shown in figure 1.
The upper samples were taken 10mm below the rail head tread of the example and comparative rail, respectively, and the lower samples were wheel steels with a brinell hardness of 350 HB.
The test conditions were as follows:
sample size: the thickness is 8mm, the inner diameter is 10mm, and the outer diameter is 20 mm;
test load: 300N;
and (3) test environment: room temperature environment;
rotating speed: the upper sample is 180r/min, and the lower sample is 200 r/min;
slip ratio: 10 percent;
total number of revolutions of the counter mill: 3X 105Next, the process is carried out.
The contact fatigue wear test results are shown in table 4.
TABLE 4 contact fatigue wear test results of examples and comparative examples
| Wear of the sample surface | Weight loss on abrasion/g | |
| Example 1 | Substantially free of cracks | 0.72 |
| Example 2 | Substantially free of cracks | 0.66 |
| Example 3 | Substantially free of cracks | 0.63 |
| Example 4 | Substantially free of cracks | 0.88 |
| Comparative example 1 | Peeling off and falling off | 1.55 |
In the contact fatigue wear test, the steel rails obtained in the examples 1 to 4 all perform well, no fatigue crack is basically observed on the surface, and the wear weight loss is controlled in a relatively stable and uniform range. The steel rail of comparative example 1 had a lower hardness, which resulted in a more severe wear loss and a surface peeling off. It can be seen that the steel rail obtained by the invention has better wear resistance and contact fatigue resistance.
The raw materials listed in the invention, the upper and lower limits and interval values of the raw materials of the invention, and the upper and lower limits and interval values of the process parameters (such as temperature, time and the like) can all realize the invention, and the examples are not listed.
While the foregoing is directed to the preferred embodiment of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.
Claims (9)
1. A rolling and cooling control high-strength pearlitic steel rail is characterized in that: the steel rail comprises the following chemical components, by mass, 0.71-0.85% of C, 0.45-0.70% of Si, 0.35-0.70% of Mn, 0.2-1.0% of Cr, 0.05-0.1% of V, 0.005-0.08% of Nb, 0-0.025% of P, 0-0.015% of S, and the balance Fe and inevitable impurities.
2. The controlled rolling and controlled cooling high strength pearlitic rail according to claim 1 wherein: the tensile strength of the steel rail is more than or equal to 1360MPa, the elongation is more than or equal to 12%, the tread hardness of the rail head is more than or equal to 390HB, the depth of a hardened layer is more than or equal to 30mm, the structure is fine lamellar pearlite, and the space between pearlite lamellae at the position which is 30mm away from the surface of the steel rail is less than or equal to 90 nm.
3. A method of producing a controlled rolling and cooling high strength pearlitic rail according to claim 1 comprising the steps of: the heating temperature is controlled to be 1160-1200 ℃, and the heating time is controlled to be 140-200 min; the initial rolling temperature is 1050-; after the steel rail is rolled, carrying out online accelerated cooling treatment on the rail head and the rail bottom of the steel rail after hot rolling, wherein the starting cooling temperature is controlled to be 680 ℃ or above, the cooling speed of the rail head is 1.0-5.0 ℃/s, the cooling speed of the rail bottom is 0.5-2.0 ℃/s, and after the temperature of the rail head is reduced to 400-500 ℃; stopping accelerated cooling, and naturally cooling to room temperature;
the steel rail production method further comprises the following steps: converter smelting, LF refining, vacuum treatment and continuous casting, wherein the procedures are not particularly limited and can be carried out according to a conventional steel rail production process method.
4. A method of producing a controlled rolling and cooling high strength pearlitic rail according to claim 3 wherein: the steel rail comprises the following chemical components, by mass, 0.71-0.85% of C, 0.45-0.70% of Si, 0.35-0.70% of Mn, 0.2-1.0% of Cr, 0.05-0.1% of V, 0.005-0.08% of Nb, 0-0.025% of P, 0-0.015% of S, and the balance Fe and inevitable impurities.
5. A method of producing a controlled rolling and cooling high strength pearlitic rail according to claim 3 wherein: the steel rail comprises the following chemical components, by mass, 0.73-0.83% of C, 0.50-0.65% of Si, 0.40-0.65% of Mn, 0.4-0.8% of Cr, 0.06-0.08% of V, 0.01-0.04% of Nb, 0-0.025% of P, 0-0.015% of S, and the balance Fe and inevitable impurities.
6. A method of producing a controlled rolling and cooling high strength pearlitic rail according to claim 3 wherein: the heating temperature is controlled to 1170-1200 ℃, and the heating time is controlled to 160-180 min; the initial rolling temperature is 1080-.
7. A method of producing a controlled rolling and cooling high strength pearlitic rail according to claim 3 wherein: after the steel rail is rolled, carrying out online accelerated cooling treatment on the hot-rolled steel rail, controlling the starting cooling temperature to be 680 ℃ and above, controlling the cooling speed of the rail head to be 2.0-4.0 ℃/s, controlling the cooling speed of the rail bottom to be 0.8-1.5 ℃/s, and after the temperature of the rail head is reduced to 420-; stopping accelerated cooling, and naturally cooling to room temperature.
8. A method of producing a controlled rolling and cooling high strength pearlitic rail according to claim 3 wherein: the rail head temperature refers to the temperature of the surface of the central part of the tread of the rail head.
9. A method of producing a controlled rolling and cooling high strength pearlitic rail according to claim 3 wherein: the accelerated cooling medium is a cooling medium commonly used in the art, including but not limited to water, polymer solution, oil, compressed air, water mist, or oil mist mixture.
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| CN202011370358.5A CN112501512A (en) | 2020-11-30 | 2020-11-30 | Controlled rolling and controlled cooling high-strength pearlitic steel rail and production method thereof |
| PCT/CN2021/104660 WO2022110812A1 (en) | 2020-11-30 | 2021-07-06 | Controlled-rolled and controlled-cooled high-strength pearlitic steel rail, and production method therefor |
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| CN113930667A (en) * | 2021-09-03 | 2022-01-14 | 武汉钢铁有限公司 | Rail with good coupling of abrasion and rolling contact fatigue and production method thereof |
| CN113981325A (en) * | 2021-11-03 | 2022-01-28 | 攀钢集团攀枝花钢铁研究院有限公司 | Medium-strength steel rail and production method thereof |
| WO2022110812A1 (en) * | 2020-11-30 | 2022-06-02 | 武汉钢铁有限公司 | Controlled-rolled and controlled-cooled high-strength pearlitic steel rail, and production method therefor |
| CN114908296A (en) * | 2022-05-31 | 2022-08-16 | 鞍钢股份有限公司 | High-hardness online heat treatment steel rail and manufacturing method thereof |
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000178690A (en) * | 1998-03-31 | 2000-06-27 | Nippon Steel Corp | Pearlitic rail excellent in resistance to wear and internal fatigue damage, and its manufacture |
| CN101880822A (en) * | 2010-07-21 | 2010-11-10 | 武汉钢铁(集团)公司 | Hot rolled high-ductility carbon steel for passenger traffic steel rails |
| CN102220545A (en) * | 2010-04-16 | 2011-10-19 | 攀钢集团有限公司 | High-carbon and high-strength heat-treated steel rail with high wear resistance and plasticity and manufacturing method thereof |
| CN105112786A (en) * | 2015-09-29 | 2015-12-02 | 燕山大学 | Super pearlite steel for steel rails and method for preparing super pearlite steel |
| WO2016171212A1 (en) * | 2015-04-22 | 2016-10-27 | 新日鐵住金株式会社 | Hot-rolled steel sheet, steel member, and method for manufacturing hot-rolled steel sheet |
| CN107723594A (en) * | 2017-10-10 | 2018-02-23 | 攀钢集团研究院有限公司 | Resistance to internal injury pearlite steel rail and its manufacture method |
| WO2020050737A1 (en) * | 2018-09-04 | 2020-03-12 | Акционерное Общество "Евраз Объединенный Западно-Сибирский Металлургический Комбинат" | Method for manufacturing railway rails with enhanced resistance to wear and contact fatigue |
| CN111607738A (en) * | 2020-06-30 | 2020-09-01 | 武汉钢铁有限公司 | Corrosion-resistant high-strength pearlitic steel rail and preparation method thereof |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112501512A (en) * | 2020-11-30 | 2021-03-16 | 武汉钢铁有限公司 | Controlled rolling and controlled cooling high-strength pearlitic steel rail and production method thereof |
-
2020
- 2020-11-30 CN CN202011370358.5A patent/CN112501512A/en active Pending
-
2021
- 2021-07-06 WO PCT/CN2021/104660 patent/WO2022110812A1/en active Application Filing
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000178690A (en) * | 1998-03-31 | 2000-06-27 | Nippon Steel Corp | Pearlitic rail excellent in resistance to wear and internal fatigue damage, and its manufacture |
| CN102220545A (en) * | 2010-04-16 | 2011-10-19 | 攀钢集团有限公司 | High-carbon and high-strength heat-treated steel rail with high wear resistance and plasticity and manufacturing method thereof |
| CN101880822A (en) * | 2010-07-21 | 2010-11-10 | 武汉钢铁(集团)公司 | Hot rolled high-ductility carbon steel for passenger traffic steel rails |
| WO2016171212A1 (en) * | 2015-04-22 | 2016-10-27 | 新日鐵住金株式会社 | Hot-rolled steel sheet, steel member, and method for manufacturing hot-rolled steel sheet |
| CN105112786A (en) * | 2015-09-29 | 2015-12-02 | 燕山大学 | Super pearlite steel for steel rails and method for preparing super pearlite steel |
| CN107723594A (en) * | 2017-10-10 | 2018-02-23 | 攀钢集团研究院有限公司 | Resistance to internal injury pearlite steel rail and its manufacture method |
| WO2020050737A1 (en) * | 2018-09-04 | 2020-03-12 | Акционерное Общество "Евраз Объединенный Западно-Сибирский Металлургический Комбинат" | Method for manufacturing railway rails with enhanced resistance to wear and contact fatigue |
| CN111607738A (en) * | 2020-06-30 | 2020-09-01 | 武汉钢铁有限公司 | Corrosion-resistant high-strength pearlitic steel rail and preparation method thereof |
Non-Patent Citations (2)
| Title |
|---|
| 刘永铨: "《钢的热处理 修订版》", 28 February 1981, 冶金工业出版社 * |
| 陈国强: "《城市轨道交通钢轨探伤工》", 31 December 2015, 中国铁道出版社 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022110812A1 (en) * | 2020-11-30 | 2022-06-02 | 武汉钢铁有限公司 | Controlled-rolled and controlled-cooled high-strength pearlitic steel rail, and production method therefor |
| CN113930667A (en) * | 2021-09-03 | 2022-01-14 | 武汉钢铁有限公司 | Rail with good coupling of abrasion and rolling contact fatigue and production method thereof |
| CN113981325A (en) * | 2021-11-03 | 2022-01-28 | 攀钢集团攀枝花钢铁研究院有限公司 | Medium-strength steel rail and production method thereof |
| CN114908296A (en) * | 2022-05-31 | 2022-08-16 | 鞍钢股份有限公司 | High-hardness online heat treatment steel rail and manufacturing method thereof |
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