CN110195192B - Ultra-low carbon bainite steel, steel rail and preparation method thereof - Google Patents
Ultra-low carbon bainite steel, steel rail and preparation method thereof Download PDFInfo
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- C—CHEMISTRY; METALLURGY
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- 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
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
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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
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
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- C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
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- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01B—PERMANENT WAY; PERMANENT-WAY TOOLS; MACHINES FOR MAKING RAILWAYS OF ALL KINDS
- E01B5/00—Rails; Guard rails; Distance-keeping means for them
- E01B5/02—Rails
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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
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Abstract
The invention discloses ultra-low carbon bainite steel, a steel rail and a preparation method thereof, and relates to the technical field of steel for railways. The bainite steel comprises the following components: c: 0.01 to 0.10 wt%, Mn: 1.8 to 2.3wt%, Si: 0.3-1.5wt%, Cr: 0.1-0.6wt%, Ni: 0.5 to 2.0wt%, Mo: 0.1-0.5wt%, V: 0.01-0.25 wt%; the balance of Fe and inevitable impurity elements, the content of each element satisfies C + (Mn + Si)/6+ Ni/15+ (Cr + Mo + V)/50 is less than or equal to 0.8, and the steel has high strength, high toughness and good welding performance. The invention also provides an ultra-low carbon bainite steel rail and a preparation method thereof, and the bainite steel rail has high strength, high low-temperature toughness, good welding performance and excellent comprehensive performance; the method is suitable for high-speed railways with the speed per hour being more than 250 kilometers.
Description
Technical Field
The invention relates to the technical field of steel for railways. More particularly, relates to ultra-low carbon bainite steel, a steel rail and a preparation method thereof.
Background
The high-speed railway (hereinafter referred to as high-speed railway) in China is rapidly developed, and the total mileage of high-speed railway operation in China exceeds 2.2 kilometers by 2016, and accounts for more than 60% of the total mileage of high-speed railway operation in the world, so that the high-speed railway becomes a flashing new business card in China. The steel rails and the turnouts for the high-speed rail are key parts influencing the operation safety of the high-speed rail, particularly the turnouts are always subjected to strong high-speed impact, and the turnouts are one of the weakest links of the high-speed rail.
At present, U75MnG and U75VG pearlite steel rails are adopted as materials for high-speed rail and turnout, the carbon content in the materials is 0.65-0.75 wt% and 0.71-0.80 wt% respectively, and the microstructure is pearlite. The high carbon content brings about two main potential safety hazards, firstly, the toughness is poor, the impact toughness of the U75MnG and U75VG pearlite steel rail is generally only 20-30J, and the fracture phenomenon occurs in the operation process, thus the operation safety of high-speed rail is seriously influenced (railway academy, 27(6), 2005); secondly, the carbon content is too high, the welding performance is not good, the cold crack generated tendency is large in the welding process, meanwhile, the hardness distribution at the joint is not uniform, so that great potential safety hazard is caused, and the comfort of high-speed rail operation is also influenced (railway construction, 8, 2016).
In recent years, bainite steel rails have gained attention from researchers at home and abroad due to their excellent toughness, wear resistance and fatigue resistance. For example, the institute of iron and steel filed "a heat treatment method for an alloy system and its bainite rail and" bainite rail "(CN 105385938A), disclosing that the carbon content of the bainite rail is 0.22-0.27 wt%, which is only for heavy haul railway applications and is not suitable for high speed railways. Beijing Temetallurgical industry and trade LLC responsibility company applies for "bainite steel and bainite steel rail for curve and heavy-duty steel rail and its production method" (CN 101921971A), and the disclosed bainite steel rail has carbon content of 0.16-0.25 wt%, and is suitable for curve and heavy-duty steel rail and high-speed railway.
In summary, the conventional pearlite steel rail for high-speed rail has poor toughness and poor welding performance due to excessively high carbon content. The bainite steel rail disclosed at present only aims at heavy haul railways, the carbon content of the bainite steel rail is still high, the welding performance cannot be burst, the improvement of low-temperature toughness is limited, and the bainite steel rail is not suitable for high speed railways. Therefore, it is necessary to develop a new rail material for high-speed railways.
Disclosure of Invention
The invention aims to provide ultra-low carbon bainite steel which comprises ultra-low carbon content and reasonable alloy element proportion, has high strength and high toughness and has good welding performance.
The second purpose of the invention is to provide an ultra-low carbon bainite steel rail which has high strength, high low-temperature toughness, good welding performance and excellent comprehensive performance.
The third purpose of the invention is to provide the application of the ultra-low carbon bainite steel rail in a high-speed railway with the speed per hour being more than 250 kilometers, and the steel rail can effectively improve the safety and the comfort of the high-speed railway.
The fourth purpose of the invention is to provide a preparation method of the ultra-low carbon bainite steel rail, and the ultra-low carbon bainite steel rail with the ultra-low carbon lath bainite structure can be obtained by the preparation method through a controlled cooling process and a tempering process.
According to a first object of the present invention, there is provided an ultra low carbon bainitic steel having a composition comprising:
c: 0.01 to 0.10 wt%, Mn: 1.8 to 2.3wt%, Si: 0.3-1.5wt%, Cr: 0.1-0.6wt%, Ni: 0.5 to 2.0wt%, Mo: 0.1-0.5wt%, V: 0.01-0.25 wt%; the balance of Fe and inevitable impurity elements, and the microstructure mainly comprises an ultra-low carbon lath bainite structure;
and the content of each element satisfies the following relational expression: c + (Mn + Si)/6+ Ni/15+ (Cr + Mo + V)/50 is less than or equal to 0.8, the relational expression is a relational expression of carbon equivalent, and the ultra-low carbon bainite steel meeting the relational expression has excellent welding performance.
Preferably, the ultra low carbon bainite steel has a composition comprising:
c: 0.01 to 0.08wt%, Mn: 2.0-2.1 wt%, Si: 0.8-1.2 wt%, Cr: 0.2-0.5 wt%, Ni: 1.0 to 1.2 wt%, Mo: 0.3-0.4 wt%, V: 0.04-0.08 wt%; the balance of Fe and inevitable impurity elements, and the microstructure mainly comprises an ultra-low carbon lath bainite structure;
and the content of each element satisfies the following relational expression: c + (Mn + Si)/6+ Ni/15+ (Cr + Mo + V)/50 is less than or equal to 0.8.
In the present invention, the properties of each element are as follows:
c, carbon element C: the steel has strong solid solution strengthening effect, is beneficial to improving the strength of steel grades, can obviously improve the quenching property of the steel grades, is not beneficial to welding steel rails when the carbon content is too high, and has ultra-low carbon content, most of the microstructure of the steel is ferrite, the strength is low, and the requirement of the steel rails on the strength cannot be met.
Manganese element Mn: is an element which can shift the CCT curve of the steel grade to the right and obviously increase the hardenability. In contrast, the manganese element can obviously delay the transformation of ferrite and pearlite in a high-temperature region, the influence on the transformation of bainite in a middle-low temperature region is small, and when the content reaches a certain value (more than or equal to 1.5 wt%), a typical high-temperature transformation region and a middle-temperature bainite transformation region which are completely separated from the left and right directions appear on a CCT curve of a steel grade, so that the hardenability of the steel grade is greatly increased, a product with a thicker size can be conveniently cooled by austenitizing high-temperature air to obtain a bainite structure with excellent performance, the production process is facilitated to be simplified, and the cost is reduced. In addition, the manganese element has the effect of solid solution strengthening, which is beneficial to improving the strength, and the content of the manganese element is increased, which is beneficial to improving the pitting corrosion resistance of the steel and the corrosion resistance of the steel to ocean atmosphere. However, if the content of manganese is too high, segregation of the components is likely to occur, which affects the stability of the structural properties.
Silicon element Si: can inhibit the precipitation of brittle carbides and is beneficial to the formation of a residual austenite film with good toughness and plasticity. The silicon can prevent the formation of acid in the rust layer, so that the inner rust layer is compact, the invasion of chloride ions is blocked, and the corrosion resistance is improved. The steel can be used with other elements such as Cr to improve the weather resistance of the steel. However, if the content of the silicon element is too high, the casting of the continuous casting billet can be influenced, and the quality of the billet can be influenced.
Chromium element Cr: has the function of solid solution strengthening, and is beneficial to improving the strength. Meanwhile, the chromium element can improve the hardenability of the steel grade and is beneficial to the uniformity of the internal and external performances of the rail head part of the steel rail. However, if the chromium content is too high, excessive martensite is formed in the steel, which affects the improvement of the toughness of the steel rail.
Molybdenum element Mo: the hardenability of the steel grade is strongly improved, and the uniform consistency of bainite structure and performance can be obtained under the air cooling condition of the steel rail. In addition, molybdenum makes the rust layer of the steel compact, and can improve the corrosion resistance of the steel in the marine atmospheric environment. Mo in the rust layer may inhibit the intrusion of chloride ions, such that the chloride ions are concentrated outside the rust layer. In addition, molybdenum increases the temper resistance of the steel. However, if the content of molybdenum is too high, on one hand, the cost of steel is increased, and on the other hand, composition segregation is caused, which affects the stability of structural properties.
Nickel element Ni: is beneficial to improving the toughness of the steel, in particular to improving the low-temperature impact toughness. If the content of nickel element is too high, the alloy cost of steel is increased.
Vanadium element V: can improve the comprehensive mechanical properties of the steel, such as strength, toughness, ductility, thermal fatigue resistance and the like, and ensure that the steel has good weldability. However, if the content of vanadium is too high, large VN particles are likely to appear, and the toughness of the steel is affected.
According to a second object of the present invention, there is provided an ultra low carbon bainite steel rail made from the ultra low carbon bainite steel described above.
According to a third object of the invention, the invention provides an application of the ultra-low carbon bainite steel rail in a high-speed railway with the speed per hour being more than 250 kilometers.
According to a fourth object of the invention, the invention provides a preparation method of an ultra-low carbon bainite steel rail, which comprises the following steps:
(1) smelting and casting the raw materials of the ultra-low carbon bainite steel with the composition by adopting a steelmaking process to obtain a casting blank;
(2) heating a casting blank, cogging, rough rolling and finish rolling to obtain a steel rail prototype;
(3) continuously cooling the steel rail prototype tread to a temperature below the bainite transformation starting temperature at a constant cooling speed, then naturally cooling to room temperature, and carrying out heat treatment to obtain the ultra-low carbon bainite steel rail. Preferably, the constant cooling rate is 2-50 ℃/s; further preferably, the steel rail prototype tread is cooled to a temperature 20-200 ℃ below the bainite transformation starting temperature at a cooling rate of 2-50 ℃/s, and then naturally cooled to room temperature. When the cooling speed of the tread of the steel rail is 2-50 ℃/s, the microscopic structure of the steel rail can be ensured to be mainly composed of lath bainite; cooling to 20-200 ℃ below the bainite transformation starting temperature, so that the phenomenon that a large amount of proeutectoid ferrite appears in a microstructure due to temperature return can be effectively avoided, and the strength and the toughness of the steel rail are improved; and then the steel rail is naturally cooled to room temperature, so that a large amount of martensite can be avoided, and the toughness of the steel rail is effectively improved. In addition, the bainite transformation start temperature is measured by forming the ultra-low carbon bainite steel into a cast slab, and measuring the bainite transformation start temperature of the cast slab under continuous cooling, and reference may be made to YB/T5128-1993 "measurement method of continuous cooling transformation curve of steel (expansion method)".
Preferably, the heating in step (2) refers to heating to 1150-1250 ℃, and keeping the temperature for 2-3 hours.
Preferably, the continuous cooling method is one or a combination of air cooling, mist cooling and air cooling, and a person skilled in the art can select the method according to actual conditions to achieve a predetermined cooling effect.
Preferably, the heat treatment is tempering treatment, the temperature of the tempering treatment is 200-.
The invention has the following beneficial effects:
1. the ultra-low carbon bainite steel and the ultra-low carbon bainite steel rail effectively improve the welding performance and the low-temperature toughness of the bainite steel and the bainite steel rail by controlling the ultra-low carbon content and controlling the reasonable proportion of each alloy element.
2. According to the invention, the ultra-low carbon bainite steel rail with the ultra-low carbon lath bainite structure is obtained by adopting the ultra-low carbon content and the reasonable alloy element proportion and combining an accurate preparation process, particularly a cooling process and a tempering process, and the welding performance and the low-temperature toughness of the bainite steel rail are improved. The comprehensive performance of the ultra-low carbon bainite steel rail obtained by the invention is obviously improved, and specifically, the tensile strength is more than or equal to 800MPa, the yield strength is more than or equal to 700MPa, the elongation is more than or equal to 15%, and the impact toughness is more than or equal to 200J/cm2The ductile-brittle transition temperature is lower than-20 ℃; the strength of the welding heat affected zone is more than or equal to 700MPa, and the toughness of the heat affected zone is more than or equal to 100J/cm2。
3. The ultra-low carbon bainite steel rail is suitable for high-speed railways with the speed per hour being more than 250 kilometers, and has important significance for improving the operation safety and comfort of the high-speed railways.
Drawings
The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.
FIG. 1 is a photograph showing the microstructure of the ultra low carbon bainite steel rail obtained in example 1.
FIG. 2 is a photograph showing the microstructure of the ultra low carbon bainite steel rail obtained in example 3.
FIG. 3 is a photograph showing the microstructure of the ultra low carbon bainite steel rail obtained in example 4.
Detailed Description
In order to more clearly illustrate the invention, the invention is further described below with reference to preferred embodiments and the accompanying drawings. It is to be understood by persons skilled in the art that the following detailed description is illustrative and not restrictive, and is not to be taken as limiting the scope of the invention.
Table 1 shows the contents (mass percentages) of the components of the bainite steel in each of the following examples and comparative examples, in which the impurities mean inevitable impurities.
TABLE 1 composition of Bainite Steel in examples and comparative examples (mass%)
Example 1
The casting slab produced in this example was measured to have a bainite transformation starting temperature of 550 ℃. The determination method refers to YB/T5128-1993 method for determining continuous cooling transformation curve diagram (expansion method) of steel.
(1) According to the formula of the embodiment in the table 1, a conventional steelmaking process is adopted, smelting and refining are carried out by a converter or an electric furnace, and then casting is carried out by adopting a continuous casting mode to obtain a casting blank;
(2) heating the casting blank to 1250 ℃, preserving heat for 2 hours, cogging, rough rolling and finish rolling to obtain a steel rail prototype;
(3) cooling the tread of the steel rail prototype to 350 ℃ at a cooling speed of 50 ℃/s by air cooling, then naturally cooling to room temperature, and tempering at 400 ℃ for 20 hours to obtain the ultra-low carbon bainite steel rail.
As shown in FIG. 1, the microstructure is mainly an ultra-low carbon lath bainite structure.
The mechanical properties of the ultra-low carbon bainite steel rail measured by the method of test example 1 are as follows: tensile strength of 800-2The ductile-brittle transition temperature is-50 ℃, after flash butt welding, the tensile strength of a heat affected zone is 700-900MPa, and the impact toughness is 200J/cm2。
Example 2
The bainite transformation starting temperature of the cast slab produced in this example was determined to be 530 ℃.
(1) According to the formula of the embodiment in the table 1, a conventional steelmaking process is adopted, smelting and refining are carried out by a converter or an electric furnace, and then casting is carried out by adopting a continuous casting mode to obtain a casting blank;
(2) heating the casting blank to 1200 ℃, preserving heat for 2 hours, cogging, rough rolling and finish rolling to obtain a steel rail prototype;
(3) cooling the tread of the steel rail prototype to 400 ℃ at the cooling speed of 30 ℃/s by air cooling, then naturally cooling to room temperature, and tempering for 30 hours at 460 ℃ to obtain the ultra-low carbon bainite steel rail, wherein the microstructure of the steel rail mainly comprises ultra-low carbon lath bainite structure.
The mechanical properties of the ultra-low carbon bainite steel rail are measured as follows: tensile strength of 900-950MPa, yield strength of 750-800MPa, elongation of 15-20%, and impact toughness of 300J/cm2The ductile-brittle transition temperature is-40 ℃, after flash butt welding is adopted, the tensile strength of a heat affected zone is 850-980MPa, and the impact toughness is 160J/cm2。
Example 3
The bainite transformation starting temperature of the cast slab produced in this example was measured to be 510 ℃.
(1) According to the formula of the embodiment in the table 1, a conventional steelmaking process is adopted, smelting and refining are carried out by a converter or an electric furnace, and then casting is carried out by adopting a continuous casting mode to obtain a casting blank;
(2) heating the casting blank to 1200 ℃, preserving heat for 3 hours, cogging, rough rolling and finish rolling to obtain a steel rail prototype;
(3) cooling the tread of the steel rail prototype to 450 ℃ at a cooling speed of 25 ℃/s by mist cooling, then naturally cooling to room temperature, and tempering at 400 ℃ for 60 hours to obtain the ultra-low carbon bainite steel rail.
As shown in FIG. 2, the steel rail has a microstructure mainly composed of an ultra-low carbon lath bainite structure.
The mechanical properties of the ultra-low carbon bainite steel rail are measured as follows: tensile strength 875-2The ductile-brittle transition temperature is-40 ℃, after flash butt welding is adopted, the tensile strength of a heat affected zone is 750-875MPa, and the impact toughness is 180J/cm2。
Example 4
The bainite transformation starting temperature of the cast slab produced in this example was 540 ℃.
(1) According to the formula of the embodiment in the table 1, a conventional steelmaking process is adopted, smelting and refining are carried out by a converter or an electric furnace, and then casting is carried out by adopting a continuous casting mode to obtain a casting blank;
(2) heating the casting blank to 1150 ℃, preserving heat for 3 hours, cogging, rough rolling and finish rolling to obtain a steel rail prototype;
(3) cooling the tread of the steel rail prototype to 520 ℃ at a cooling speed of 10 ℃/s by air cooling, and then naturally cooling to room temperature; and tempering at 200 deg.c for 60 hr to obtain ultra-low carbon bainite steel rail.
As shown in FIG. 3, the steel rail has a microstructure mainly composed of an ultra-low carbon lath bainite structure.
The mechanical properties of the ultra-low carbon bainite steel rail are measured as follows: tensile strength of 850-900MPa, yield strength of 700-750MPa, elongation of 16-18% and impact toughness of 280J/cm2The ductile-brittle transition temperature is-30 ℃, the tensile strength of a heat affected zone is 850-950MPa after flash butt welding is adopted,the impact toughness is 120J/cm2。
Example 5
The bainite transformation starting temperature of the cast slab produced in this example was 480 ℃ as measured.
(1) According to the formula of the embodiment in the table 1, a conventional steelmaking process is adopted, smelting and refining are carried out by a converter or an electric furnace, and then casting is carried out by adopting a continuous casting mode to obtain a casting blank;
(2) heating the casting blank to 1200 ℃, preserving heat for 2 hours, cogging, rough rolling and finish rolling to obtain a steel rail prototype;
(3) cooling the tread of the steel rail prototype to 300 ℃ at a cooling speed of 2 ℃/s by fog cooling, and then naturally cooling to room temperature; and tempering at 500 deg.c for 40 hr to obtain the ultra-low carbon bainite steel rail with the steel rail microstructure mainly including the bainite structure of the ultra-low carbon plate.
The mechanical properties of the ultra-low carbon bainite steel rail are measured as follows: tensile strength of 975-2The ductile-brittle transition temperature is-20 ℃, after flash butt welding is adopted, the tensile strength of a heat affected zone is 950-1100MPa, and the impact toughness is 100J/cm2。
Comparative example 1
Example 1 was repeated except that the heated rail prototype in step (3) was directly cooled naturally to room temperature. The tensile strength of the obtained steel rail is 400-500 MPa.
Comparative example 2
Example 2 was repeated with the difference that in step (3) the rail was not tempered between 460 ℃ for 30 hours. The ductile-brittle transition temperature of the obtained steel rail is-15 ℃;
comparative example 3
Example 5 was repeated with the difference that the carbon content was 0.18 wt.%. The impact toughness of the obtained steel rail is 80J, and the ductile-brittle transition temperature is 25 ℃.
Comparative example 4
Example 2 was repeated according to the formulation of this comparative example in table 1, with the difference that the carbon content was different, C + (Mn + Si)/6+ Ni/15+ (Cr + Mo + V)/50 ═ 0.86 > 0.8. The obtained steel rail has an impact toughness of 50J and a ductile-brittle transition temperatureAt 10 ℃, after flash butt welding, the tensile strength of a heat affected zone is 1300-1400MPa, and the impact toughness is 20J/cm2And weld level cracking occurred.
Test example 1
Mechanical property test
The mechanical properties of the steel rail samples prepared in the examples and comparative examples were measured by a universal tensile tester using standard tensile test specimens according to the regulations of the relevant national standards. The test result shows that the mechanical property of the ultra-low carbon bainite steel rail obtained by the invention is obviously improved, and specifically, the tensile strength is more than or equal to 800MPa, the yield strength is more than or equal to 700MPa, the elongation is more than or equal to 15%, and the impact toughness is more than or equal to 200J/cm2The ductile-brittle transition temperature is lower than-20 ℃; the strength of the welding heat affected zone is more than or equal to 700MPa, and the toughness of the heat affected zone is more than or equal to 100J/cm2Has high strength and high toughness.
It should be understood that the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention, and it will be obvious to those skilled in the art that other variations or modifications may be made on the basis of the above description, and all embodiments may not be exhaustive, and all obvious variations or modifications that are included in the technical solutions of the present invention are within the scope of the present invention.
Claims (5)
1. An ultra-low carbon bainite steel rail for a high-speed railway is characterized by comprising the following raw materials:
c: 0.01 to 0.08wt%, Mn: 1.8 to 2.3wt%, Si: 0.3-1.5wt%, Cr: 0.1-0.6wt%, Ni: 0.5 to 2.0wt%, Mo: 0.1-0.5wt%, V: 0.01-0.25 wt%; the balance of Fe and inevitable impurity elements, and the microstructure mainly comprises an ultra-low carbon lath bainite structure;
and the content of each element satisfies the following relational expression: c + (Mn + Si)/6+ Ni/15+ (Cr + Mo + V)/50 is more than or equal to 0.52 and less than or equal to 0.67;
the preparation method comprises the following steps:
(1) smelting and casting the raw materials of the ultra-low carbon bainite steel rail by adopting a steelmaking process to obtain a casting blank;
(2) heating a casting blank, cogging, rough rolling and finish rolling to obtain a steel rail prototype;
(3) continuously cooling the steel rail prototype tread to 20-200 ℃ below the bainite transformation starting temperature at a constant cooling rate, then naturally cooling to room temperature, and carrying out heat treatment to obtain the ultra-low carbon bainite steel rail;
wherein the constant cooling rate in the step (3) is 2-50 ℃/s; the heat treatment is tempering treatment, the temperature of the tempering treatment is 200-500 ℃, and the heat preservation time of the tempering treatment is 20-60 hours.
2. Use of the ultra low carbon bainitic steel rail according to claim 1 for high speed railways at speeds greater than 250 km/h.
3. The method for preparing an ultra-low carbon bainite steel rail for a high speed railway according to claim 1 includes the following steps:
(1) smelting and casting raw materials of the ultra-low carbon bainite steel rail by adopting a steelmaking process to obtain a casting blank;
(2) heating a casting blank, cogging, rough rolling and finish rolling to obtain a steel rail prototype;
(3) continuously cooling the steel rail prototype tread to 20-200 ℃ below the bainite transformation starting temperature at a constant cooling rate, then naturally cooling to room temperature, and carrying out heat treatment to obtain the ultra-low carbon bainite steel rail;
wherein the constant cooling rate in the step (3) is 2-50 ℃/s; the heat treatment is tempering treatment, the temperature of the tempering treatment is 200-500 ℃, and the heat preservation time of the tempering treatment is 20-60 hours.
4. The method for preparing an ultra-low carbon bainite steel rail for a high-speed railway according to claim 3, wherein the heating in the step (2) is heating to 1150-1250 ℃ and keeping the temperature for 2-3 hours.
5. The method for preparing the ultra-low carbon bainite steel rail for a high-speed railway according to claim 3, wherein the continuous cooling method is one or more of air cooling, mist cooling and air cooling.
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| CN201810156086.5A CN110195192B (en) | 2018-02-24 | 2018-02-24 | Ultra-low carbon bainite steel, steel rail and preparation method thereof |
| PCT/CN2019/075365 WO2019161760A1 (en) | 2018-02-24 | 2019-02-18 | Ultra-low carbon bainitic steel, steel rail, and preparation method therefor |
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| CN116083696A (en) * | 2022-12-15 | 2023-05-09 | 攀钢集团攀枝花钢铁研究院有限公司 | Production method of steel for stable incomplete austenite bainite frog |
Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1256323A (en) * | 1998-12-07 | 2000-06-14 | 清华大学 | High-strength and high-toughness weldable air-cooled Hongkang bainite steel specially for railway frog |
| JP2000199041A (en) * | 1999-01-07 | 2000-07-18 | Nippon Steel Corp | Bainitic rail excellent in rolling fatigue damaging resistance and inside fatigue damaging resistance |
| CN1693520A (en) * | 2005-04-18 | 2005-11-09 | 河南省强力机械有限公司 | Quasi bainitic steel |
| CN1721565A (en) * | 2004-07-13 | 2006-01-18 | 铁道科学研究院 | Full-bainite steel frog containing stable residual austenite and production process thereof |
| CN101921971A (en) * | 2010-09-08 | 2010-12-22 | 北京特冶工贸有限责任公司 | Bainite steel and bainite steel rail used for curve and heavy load steel rail, and production method thereof |
| CN102534387A (en) * | 2011-12-12 | 2012-07-04 | 中国铁道科学研究院金属及化学研究所 | Bainite/martensite steel rail with 1,500 Mpa level of high toughness and manufacturing method thereof |
| CN103160736A (en) * | 2011-12-14 | 2013-06-19 | 鞍钢股份有限公司 | High-strength bainite steel rail and heat treatment process thereof |
| CN105316596A (en) * | 2014-06-13 | 2016-02-10 | 北京交通大学 | Ultra-low-phosphorus bainite steel and bainite steel rail thereof |
| CN106893832A (en) * | 2015-12-18 | 2017-06-27 | 北京交通大学 | A kind of BQ ＆ P Technologies for Heating Processing of carbides-free shellfish/horse Multiphase Steel |
| CN107130171A (en) * | 2017-05-26 | 2017-09-05 | 北京交通大学 | A kind of middle low carbon high-strength high-ductility corrosion bainitic steel, rail and preparation method |
| CN107326302A (en) * | 2017-05-26 | 2017-11-07 | 北京交通大学 | A kind of anti-corrosion bainitic steel, rail and preparation method |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3522613B2 (en) * | 1999-11-26 | 2004-04-26 | 新日本製鐵株式会社 | Bainitic rails with excellent rolling fatigue damage resistance, internal fatigue damage resistance, and welded joint characteristics, and manufacturing methods thereof |
| CN103789699A (en) * | 2012-11-03 | 2014-05-14 | 无锡市森信精密机械厂 | Preparation process of bainitic steel for point rail of frog |
| CN103805903A (en) * | 2012-11-03 | 2014-05-21 | 无锡市森信精密机械厂 | Bainitic steel applied to frog |
| CN103409694A (en) * | 2013-08-09 | 2013-11-27 | 内蒙古包钢钢联股份有限公司 | Steel for low-carbon microalloying bainite steel rails and manufacturing method thereof |
| CN105063511B (en) * | 2015-08-14 | 2017-03-22 | 武汉钢铁(集团)公司 | Ultra-low carbon bainite thin gauge steel plate rolled through heavy and medium plate mill and production method of ultra-low carbon bainite thin gauge steel plate |
-
2018
- 2018-02-24 CN CN201810156086.5A patent/CN110195192B/en active Active
-
2019
- 2019-02-18 WO PCT/CN2019/075365 patent/WO2019161760A1/en active Application Filing
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1256323A (en) * | 1998-12-07 | 2000-06-14 | 清华大学 | High-strength and high-toughness weldable air-cooled Hongkang bainite steel specially for railway frog |
| JP2000199041A (en) * | 1999-01-07 | 2000-07-18 | Nippon Steel Corp | Bainitic rail excellent in rolling fatigue damaging resistance and inside fatigue damaging resistance |
| CN1721565A (en) * | 2004-07-13 | 2006-01-18 | 铁道科学研究院 | Full-bainite steel frog containing stable residual austenite and production process thereof |
| CN1693520A (en) * | 2005-04-18 | 2005-11-09 | 河南省强力机械有限公司 | Quasi bainitic steel |
| CN101921971A (en) * | 2010-09-08 | 2010-12-22 | 北京特冶工贸有限责任公司 | Bainite steel and bainite steel rail used for curve and heavy load steel rail, and production method thereof |
| CN102534387A (en) * | 2011-12-12 | 2012-07-04 | 中国铁道科学研究院金属及化学研究所 | Bainite/martensite steel rail with 1,500 Mpa level of high toughness and manufacturing method thereof |
| CN103160736A (en) * | 2011-12-14 | 2013-06-19 | 鞍钢股份有限公司 | High-strength bainite steel rail and heat treatment process thereof |
| CN105316596A (en) * | 2014-06-13 | 2016-02-10 | 北京交通大学 | Ultra-low-phosphorus bainite steel and bainite steel rail thereof |
| CN106893832A (en) * | 2015-12-18 | 2017-06-27 | 北京交通大学 | A kind of BQ ＆ P Technologies for Heating Processing of carbides-free shellfish/horse Multiphase Steel |
| CN107130171A (en) * | 2017-05-26 | 2017-09-05 | 北京交通大学 | A kind of middle low carbon high-strength high-ductility corrosion bainitic steel, rail and preparation method |
| CN107326302A (en) * | 2017-05-26 | 2017-11-07 | 北京交通大学 | A kind of anti-corrosion bainitic steel, rail and preparation method |
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| CN110195192A (en) | 2019-09-03 |
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