WO2019161760A1 - 一种超低碳贝氏体钢、钢轨及其制备方法 - Google Patents

一种超低碳贝氏体钢、钢轨及其制备方法 Download PDF

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WO2019161760A1
WO2019161760A1 PCT/CN2019/075365 CN2019075365W WO2019161760A1 WO 2019161760 A1 WO2019161760 A1 WO 2019161760A1 CN 2019075365 W CN2019075365 W CN 2019075365W WO 2019161760 A1 WO2019161760 A1 WO 2019161760A1
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ultra
low carbon
rail
steel
bainite
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PCT/CN2019/075365
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English (en)
French (fr)
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高古辉
白秉哲
张绵胜
张志强
桂晓露
翁宇庆
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北京交通大学
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    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING 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
    • C21D9/00Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/04Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for rails
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/02Ferrous alloys, e.g. steel alloys containing silicon
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/04Ferrous alloys, e.g. steel alloys containing manganese
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/08Ferrous alloys, e.g. steel alloys containing nickel
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/10Ferrous alloys, e.g. steel alloys containing cobalt
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/12Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/18Ferrous alloys, e.g. steel alloys containing chromium
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/18Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/18Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/46Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/18Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/58Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
    • EFIXED CONSTRUCTIONS
    • E01CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01BPERMANENT WAY; PERMANENT-WAY TOOLS; MACHINES FOR MAKING RAILWAYS OF ALL KINDS
    • E01B5/00Rails; Guard rails; Distance-keeping means for them
    • E01B5/02Rails
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING 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
    • C21D2211/00Microstructure comprising significant phases
    • C21D2211/002Bainite

Definitions

  • the invention relates to the field of railway steel technology. More specifically, it relates to an ultra-low carbon bainitic steel, a rail, and a method of preparing the same.
  • high-speed rail China's high-speed railway
  • the Belt and Road Initiative provides a foundation for construction. Rails and ballasts for high-speed rail are the key components affecting the safety of high-speed rail operations.
  • the switch has been subjected to strong high-speed impact and is one of the weakest links in the high-speed rail track.
  • the materials used in high-speed rail and ballast are U75MnG and U75VG pearlite rails.
  • the carbon content of these materials is 0.65-0.75wt% and 0.71-0.80wt%, respectively, and the microstructure is pearlite.
  • the higher carbon content brings two major safety hazards.
  • the impact toughness of U75MnG and U75VG pearlite rails is generally only 20-30J.
  • the fracture phenomenon occurs during operation, which seriously affects the operation safety of high-speed rail ( Journal of the Chinese Society of railways, 27(6), 2005);
  • the carbon content is too high, the welding performance is not good, the tendency of cold cracks in the welding process is large, and the hardness distribution at the joint is not uniform, which causes great safety hazards. It also affects the comfort of high-speed rail operations (railway construction, 8, 2016).
  • bainitic rails have attracted the attention of scholars at home and abroad due to their excellent toughness, wear resistance and fatigue resistance.
  • the disclosed bainitic rails have a carbon content of 0.22-0.27 wt%, only for The application of heavy-duty railways does not apply to high-speed railways.
  • Beijing Teye Industry and Trade Co., Ltd. applied for “bainitic and bainitic rails for curved and heavy-duty rails and its production method” (CN 101921971A).
  • the disclosed bainitic rail carbon content is 0.16-0.25wt%. For curved and heavy-duty rails, not for high-speed rail.
  • a second object of the present invention is to provide an ultra-low carbon bainitic steel rail which has high strength, high low temperature toughness, good welding performance and excellent overall performance.
  • a third object of the present invention is to provide an application of an ultra-low carbon bainitic rail as described above in a high speed railway having a speed of more than 250 kilometers per hour, which can effectively improve the safety and comfort of a high speed railway.
  • a fourth object of the present invention is to provide a method for preparing an ultra-low carbon bainitic steel rail, which can obtain an ultra-low carbon having an ultra-low carbon lath bainite structure by controlling a cooling process and a tempering process. Bainitic rail.
  • the present invention provides an ultra-low carbon bainitic steel, the composition comprising:
  • the ultra low carbon bainitic steel has a composition comprising:
  • Carbon C It has a strong solid solution strengthening effect, which is beneficial to the improvement of steel strength and can significantly improve the hardenability of steel grades. However, when the carbon content is too high, it is not conducive to the welding of steel rails. When the carbon content is extremely low, steel Most of the microstructures are ferrite, and the strength is low, which cannot meet the requirements of the rail for strength.
  • Manganese element Mn is an element that shifts the CCT curve of the steel species to the right and significantly increases the hardenability. Relatively speaking, manganese can significantly delay the transformation of ferrite and pearlite in the high temperature region, but has little effect on the bainite transformation in the middle and low temperature regions. When a certain content is reached ( ⁇ 1.5wt%), the CCT curve of the steel can be made. The typical high-temperature transition zone and the medium-temperature bainite transformation zone which are completely separated from the upper and lower directions are greatly increased, and the hardenability of the steel is greatly improved, which is advantageous for obtaining a high-quality air-cooled product from austenitizing high-temperature air cooling. The bainite structure makes it easy to simplify the production process and reduce costs.
  • manganese has a solid solution strengthening effect, which is beneficial to the improvement of strength, and the increase of manganese content is beneficial to improve the pitting resistance of steel and the corrosion resistance to the marine atmosphere.
  • the content of manganese is too high, segregation of components may occur, which may affect the stability of tissue properties.
  • Silicon Si It can suppress the precipitation of brittle carbides, which is favorable for the formation of a good austenitic film with good toughness and plasticity. Silicon can prevent the formation of acid in the rust layer, make the inner rust layer dense, hinder the intrusion of chloride ions, and improve the corrosion resistance. Used in combination with other elements such as Cr, the weather resistance of steel is better. However, if the content of silicon is too high, it will affect the casting of the continuous casting billet and affect the quality of the billet.
  • Chromium Cr It has a solid solution strengthening effect and is advantageous for strength improvement. At the same time, the chromium element can improve the hardenability of the steel grade, which is beneficial to the uniformity of the inner and outer performance of the rail head portion. However, if the chromium content is high, excessive martensite is formed in the steel, which affects the toughness of the rail.
  • Molybdenum element Mo strongly improve the hardenability of steel grades, which is beneficial to the uniformity of bainite structure and properties under the condition of rail air cooling.
  • molybdenum makes the steel rust layer dense, which can improve the corrosion resistance of steel in the marine atmosphere.
  • the Mo in the rust layer inhibits the intrusion of chloride ions, so that the chloride ions concentrate outside the rust layer.
  • molybdenum can increase the tempering resistance of steel. However, if the content of molybdenum is too high, on the one hand, it will increase the cost of steel, on the other hand, it will cause segregation of components and affect the stability of tissue performance.
  • Nickel Ni It is beneficial to improve the toughness of steel, especially the improvement of low temperature impact toughness. If the nickel content is too high, it will increase the alloy cost of the steel.
  • Vanadium V It can improve the comprehensive mechanical properties such as strength, toughness, ductility and thermal fatigue resistance of steel, and make steel have good weldability. However, if the content of vanadium is too high, large VN particles are likely to appear, which affects the toughness of the steel.
  • the present invention provides an ultra-low carbon bainitic rail made of ultra-low carbon bainitic steel as described above.
  • the present invention provides the use of an ultra-low carbon bainitic rail as described above in a high speed railway having a speed of more than 250 kilometers per hour.
  • the present invention provides a method for preparing an ultra-low carbon bainitic steel rail, comprising the steps of:
  • the rail prototyping surface is continuously cooled at a constant cooling rate to below the bainite transformation starting temperature, and then naturally cooled to room temperature for heat treatment to obtain an ultra-low carbon bainite rail.
  • the constant cooling rate is 2-50 ° C / s; further preferably, first, the rail prototype tread is cooled at a cooling rate of 2-50 ° C / s to a temperature of 20-200 ° C below the bainite transformation starting temperature, It is then naturally cooled to room temperature.
  • the microstructure of the rail can be ensured to be mainly bainite; cooling to the temperature below the bainite transformation start temperature is 20-200 ° C, which can effectively avoid the return temperature The result is a large amount of pro-eutectoid ferrite in the microstructure, thereby improving the strength and toughness of the rail; then the rail is naturally cooled to room temperature to avoid a large amount of martensite and effectively improve the toughness of the rail.
  • the bainite transformation starting temperature is that the ultra-low carbon bainitic steel is made into a slab, and the bainite transformation starting temperature of the slab under continuous cooling is measured.
  • the measurement method refer to YB/T5128- 1993 "Method for determination of continuous cooling transition curve of steel (expansion method)".
  • heating in step (2) means heating to 1150-1250 ° C for 2-3 hours.
  • the method of cooling is one or a combination of air cooling, mist cooling or air cooling, and those skilled in the art can select according to actual conditions, and can achieve a predetermined cooling effect.
  • the heat treatment is tempering treatment
  • the temperature of the tempering treatment is 200-500 ° C
  • the heat preservation time of the tempering treatment is 20-60 hours to promote partial merging of bainite slabs and stabilize ultra-low carbon slats Bainite structure, reducing the ductile-brittle transition temperature.
  • the ultra-low carbon bainitic steel and the ultra-low carbon bainitic steel rail of the invention effectively improve the bainite steel and the bainite rail by controlling the ultra-low carbon content while controlling the reasonable proportion of each alloying element. Solderability and low temperature toughness.
  • the invention obtains ultra-low ultra-low carbon slat bainite structure by adopting ultra-low carbon content and reasonable alloying element ratio, combined with precise preparation process, especially controlling cooling process and tempering process.
  • Carbon bainite rails improve the weldability and low temperature toughness of bainitic rails.
  • the comprehensive performance of the ultra-low carbon bainitic steel rail obtained by the invention is obviously improved, specifically, the tensile strength is ⁇ 800 MPa, the yield strength is ⁇ 700 MPa, the elongation is ⁇ 15%, the impact toughness is ⁇ 200 J/cm 2 , and the ductile-brittle transition
  • the temperature is lower than -20 ° C; the strength of the weld heat affected zone is ⁇ 700 MPa, and the toughness of the heat affected zone is ⁇ 100 J/cm 2 .
  • the ultra-low carbon bainitic steel rail of the invention is suitable for high-speed railway with a speed of more than 250 km per hour, which is of great significance for improving the safety and comfort of high-speed railway operation.
  • Figure 1 shows a photomicrograph of the ultra-low carbon bainite rail obtained in Example 1.
  • Figure 2 shows a photomicrograph of the ultra-low carbon bainite rail obtained in Example 3.
  • Figure 3 shows a photomicrograph of the ultra-low carbon bainite rail obtained in Example 4.
  • Table 1 shows the component contents (mass percentage) of the bainitic steel in the following respective examples and comparative examples, in which impurities refer to unavoidable impurities.
  • Table 1 Composition content (mass percentage) of bainitic steel in each of the examples and comparative examples
  • the bainite transformation starting temperature of the cast slab produced in this example was determined to be 550 °C.
  • Method for Measuring Continuous Cooling Transformation Curve of Steel Expansion Method
  • the steel rail prototype tread is cooled to 350 ° C at a cooling rate of 50 ° C / s by air cooling, then naturally cooled to room temperature, and then tempered between 400 ° C for 20 hours to obtain an ultra-low carbon bainitic rail.
  • the microstructure is mainly composed of ultra-low carbon slab bainite.
  • the mechanical properties of the ultra-low carbon bainite rail measured by the method of Test Example 1 were: tensile strength 800-850 MPa, yield strength 700-775 MPa, elongation 15-18%, impact toughness 300 J/cm 2 , ductile and brittle
  • the transition temperature is -50 ° C. After flash butt welding, the tensile strength of the heat-affected zone is 700-900 MPa, and the impact toughness is 200 J/cm 2 .
  • the bainite transformation starting temperature of the cast slab produced in this example was determined to be 530 °C.
  • the mechanical properties of the ultra-low carbon bainite rail are as follows: tensile strength 900-950 MPa, yield strength 750-800 MPa, elongation 15-20%, impact toughness 300 J/cm 2 , ductile-brittle transition temperature -40 ° C, After flash butt welding, the tensile strength of the heat-affected zone is 850-980 MPa, and the impact toughness is 160 J/cm 2 .
  • the bainite transformation starting temperature of the cast slab produced in this example was determined to be 510 °C.
  • the microstructure of the rail is dominated by ultra-low carbon slab bainite.
  • the mechanical properties of the ultra-low carbon bainite rail are as follows: tensile strength 875-925MPa, yield strength 775-800MPa, elongation 16-20%, impact toughness 280J/cm 2 , ductile-brittle transition temperature -40 °C, After flash butt welding, the tensile strength of the heat-affected zone is 750-875 MPa, and the impact toughness is 180 J/cm 2 .
  • the bainite transformation starting temperature of the cast slab produced in this example was determined to be 540 °C.
  • the steel rail prototype tread is cooled to 520 ° C at a cooling rate of 10 ° C / s by air cooling, and then naturally cooled to room temperature; and then tempered between 200 ° C for 60 hours to obtain an ultra-low carbon bainitic rail.
  • the microstructure of the rail is dominated by ultra-low carbon slab bainite.
  • the mechanical properties of the ultra-low carbon bainite rail are as follows: tensile strength 850-900 MPa, yield strength 700-750 MPa, elongation 16-18%, impact toughness 280 J/cm 2 , ductile-brittle transition temperature -30 ° C, After flash butt welding, the tensile strength of the heat-affected zone is 850-950 MPa, and the impact toughness is 120 J/cm 2 .
  • the bainite transformation starting temperature of the cast slab produced in this example was measured to be 480 °C.
  • the mechanical properties of the ultra-low carbon bainite rail are as follows: tensile strength 975-1050 MPa, yield strength 900-950 MPa, elongation 15-17%, impact toughness 200 J/cm 2 , ductile-brittle transition temperature -20 ° C, After flash butt welding, the tensile strength of the heat-affected zone is 950-1100 MPa, and the impact toughness is 100 J/cm 2 .
  • Example 1 was repeated except that the heated rail prototype in step (3) was naturally cooled to room temperature.
  • the resulting rail has a tensile strength of 400-500 MPa.
  • Example 2 was repeated except that the rail was not tempered at 460 ° C for 30 hours in step (3).
  • the obtained rail has a ductile-brittle transition temperature of -15 ° C;
  • Example 5 was repeated except that the carbon content was 0.18 wt.%.
  • the obtained rail had an impact toughness of 80 J and a ductile-brittle transition temperature of 25 °C.
  • the obtained rail has an impact toughness of 50 J and a ductile-brittle transition temperature of 10 ° C. After flash butt welding, the tensile strength of the heat-affected zone is 1300-1400 MPa, the impact toughness is 20 J/cm 2 , and horizontal cracks occur.
  • the mechanical properties of the rail samples prepared in each of the examples and the comparative examples were measured by a universal tensile tester using standard tensile specimens according to the relevant national standards. It can be seen from the test results that the mechanical properties of the ultra-low carbon bainitic steel rail obtained by the invention are obviously improved, specifically, the tensile strength is ⁇ 800 MPa, the yield strength is ⁇ 700 MPa, the elongation is ⁇ 15%, and the impact toughness is ⁇ 200J.
  • the ductile-brittle transition temperature is lower than -20 °C; the strength of the weld heat affected zone is ⁇ 700 MPa, and the toughness of the heat affected zone is ⁇ 100 J/cm 2 , which has good performance of high strength and high toughness.

Abstract

一种超低碳贝氏体钢,包含:C:0.01-0.10wt%,Mn:1.8-2.3wt%,Si:0.3-1.5wt%,Cr:0.1-0.6wt%,Ni:0.5-2.0wt%,Mo:0.1-0.5wt%,V:0.01-0.25wt%;其余为Fe和不可避免的杂质元素,各元素的含量满足C+(Mn+Si)/6+Ni/15+(Cr+Mo+V)/50≤0.8。采用所述超低碳贝氏体钢制备钢轨以及该钢轨的制备方法。该贝氏体钢轨强度大,低温韧性高,焊接性能佳,综合性能优良,适用于时速大于250公里的高速铁路。

Description

一种超低碳贝氏体钢、钢轨及其制备方法 技术领域
本发明涉及铁路用钢技术领域。更具体地,涉及一种超低碳贝氏体钢、钢轨及其制备方法。
背景技术
我国高速铁路(以下简称高铁)迅速发展,至2016年底,我国高铁运营总里程超过2.2万公里,占世界高铁运营总里程的60%以上,成为我国一张闪亮的新名片,也为布局“一带一路”战略提供建设基础。而高铁用钢轨、道岔是影响高铁运营安全的关键部件,特别是道岔一直受到强烈的高速冲击,是高铁轨道最薄弱的环节之一。
目前高铁钢轨、道岔采用的材料均是采用U75MnG和U75VG珠光体钢轨,该类材料中碳含量分别为0.65-0.75wt%和0.71-0.80wt%,显微组织为珠光体。较高的碳含量带来两个主要的安全隐患,一是韧性差,U75MnG和U75VG珠光体钢轨的冲击韧性一般只有20-30J,在运营过程中出现断裂现象,严重影响了高铁的运营安全(铁道学报,27(6),2005);二是含碳量过高,焊接性能不佳,焊接过程中冷裂纹产生的倾向较大,同时接头处硬度分布不均匀,造成了很大的安全隐患,也影响了高铁运营的舒适性(铁道建筑,8,2016)。
近年来,贝氏体钢轨由于其优异的韧性、耐磨性和抗疲劳性能而得到国内外学者的关注。例如,钢铁研究总院申请了“一种合金体系及其贝氏体钢轨的热处理方法以及贝氏体钢轨”(CN 105385938A),公开的贝氏体钢轨碳含量为0.22-0.27wt%,只是针对重载铁路的应用,不适用于高速铁路。北京特冶工贸有限责任公司申请了“曲线和重载钢轨用贝氏体钢和贝氏体钢轨及其生产方法”(CN 101921971A),公开的贝氏体钢轨碳含量为0.16-0.25wt%,针对的是曲线和重载钢轨,不适用于高速铁路。
综上所述,目前高铁用珠光体钢轨由于其碳含量过高导致其韧性差,焊接性能不佳。而目前公开的贝氏体钢轨只是针对重载铁路,且其碳含量仍然较高,焊接性能不能得到突破,低温韧性改善有限,不适用于高速铁路。因此,有必要开发一种新型的高速铁路用钢轨材料。
发明内容
本发明的一个目的在于提供一种超低碳贝氏体钢,其包括超低的碳含量和合理的合金元素配比,具有高强度、高韧性,且焊接性能佳。
本发明的第二个目的在于提供一种超低碳贝氏体钢轨,该贝氏体钢轨强度大,低温韧性高,焊接性能佳,综合性能优良。
本发明的第三个目的在于提供一种如上所述的超低碳贝氏体钢轨在时速大于250公里 的高速铁路中的应用,该钢轨可有效提高高速铁路的安全性和舒适性。
本发明的第四个目的在于提供一种超低碳贝氏体钢轨的制备方法,该制备方法通过控制冷却工艺和回火工艺,可获得具有超低碳板条贝氏体组织的超低碳贝氏体钢轨。
根据本发明的第一个目的,本发明提供一种超低碳贝氏体钢,其组成包含:
C:0.01-0.10wt%,Mn:1.8-2.3wt%,Si:0.3-1.5wt%,Cr:0.1-0.6wt%,Ni:0.5-2.0wt%,Mo:0.1-0.5wt%,V:0.01-0.25wt%;其余为Fe和不可避免的杂质元素,显微组织主要为超低碳板条贝氏体组织;
且各元素的含量满足以下关系式:C+(Mn+Si)/6+Ni/15+(Cr+Mo+V)/50≤0.8,该关系式是碳当量的关系式,满足该关系式的超低碳贝氏体钢具有优异的焊接性能。
优选地,所述超低碳贝氏体钢其组成包含:
C:0.01-0.08wt%,Mn:2.0-2.1wt%,Si:0.8-1.2wt%,Cr:0.2-0.5wt%,Ni:1.0-1.2wt%,Mo:0.3-0.4wt%,V:0.04-0.08wt%;其余为Fe和不可避免的杂质元素,显微组织主要为超低碳板条贝氏体组织;
且各元素的含量满足以下关系式:C+(Mn+Si)/6+Ni/15+(Cr+Mo+V)/50≤0.8。
在本发明中,各元素的性能如下:
碳元素C:具有强烈的固溶强化作用,有利于钢种强度的提高,能显著提高钢种的淬透性,但碳含量过高时不利于钢轨的焊接,碳含量超低时,钢的显微组织多为铁素体,强度偏低,不能满足钢轨对强度的要求。
锰元素Mn:是使钢种CCT曲线右移,显著增加淬透性的元素。相对而言,锰元素能显著延缓高温区铁素体和珠光体转变,而对中低温区贝氏体转变的影响较小,达到一定含量时(≥1.5wt%),能使钢种CCT曲线上出现上下与左右方向完全分开的典型的高温转变区和中温贝氏体转变区,大大增加了钢种淬透性,有利于尺寸较厚的产品从奥氏体化高温空冷即可获得性能优良的贝氏体组织,便于简化生产工艺和降低成本。此外,锰元素有固溶强化的作用,有利于强度的提高,且锰元素含量增加,有利于提高钢的耐点蚀能力和对海洋大气的耐蚀性。但是如果锰元素含量过高容易造成成分的偏析,影响组织性能稳定性。
硅元素Si:可抑制脆性的碳化物析出,利于韧塑性配合良好的残余奥氏体膜的形成。硅可阻止锈层中酸的形成,使内锈层致密,阻碍氯离子侵入,提高抗腐蚀能力。与其他元素如Cr等的配合使用可使钢耐候性效果更好。但是如果硅元素含量过高,会影响连铸坯的浇铸,影响钢坯的质量。
铬元素Cr:具有固溶强化的作用,有利于强度的提高。同时,铬元素能提高钢种的淬透性,有利于钢轨轨头部分内外性能的均匀一致。但是如果铬元素含量偏高,会在钢中形成过量的马氏体,影响钢轨的韧性改善。
钼元素Mo:强烈提高钢种的淬透性,有利于钢轨空冷条件下即可获得贝氏体组织和性能的均匀一致性。此外,钼使得钢的锈层致密,可提高钢在海洋大气环境中的抗腐蚀能力。锈层中的Mo可抑制氯离子的侵入,使得氯离子集中于锈层外部。此外,钼元素可提高钢的回火抗力。但是如果钼元素含量过高,一方面会增加钢的成本,另一方面也会造成成分的偏析,影响组织性能稳定性。
镍元素Ni:有利于提高钢的韧性,尤其是低温冲击韧性的提高。如果镍元素含量过高, 会增加钢的合金成本。
钒元素V:可提高钢的强度、韧性、延展性及抗热疲劳性等综合机械性能,并使钢具有良好的可焊性。但是如果钒元素含量过高,易出现大的VN颗粒出现,影响钢的韧性。
根据本发明的第二个目的,本发明提供一种超低碳贝氏体钢轨,该钢轨由如上所述的超低碳贝氏体钢制成。
根据本发明的第三个目的,本发明提供一种如上所述的超低碳贝氏体钢轨在时速大于250公里的高速铁路中的应用。
根据本发明的第四个目的,本发明提供一种超低碳贝氏体钢轨的制备方法,包括以下步骤:
(1)将具有上述组成的超低碳贝氏体钢的原料采用炼钢工艺进行冶炼、铸造,得铸坯;
(2)将铸坯加热,开坯,粗轧,精轧,得钢轨原型;
(3)将钢轨原型踏面处以恒定冷速连续冷却至贝氏体转变开始温度以下,然后自然冷却至室温,进行热处理,得超低碳贝氏体钢轨。优选地,所述恒定冷速为2-50℃/s;进一步优选地,首先钢轨原型踏面处以2-50℃/s的冷却速度冷却至贝氏体转变开始温度以下20-200℃的温度,然后自然冷却至室温。当钢轨踏面的冷却速度为2-50℃/s时,可以保证钢轨的显微组织以板条贝氏体为主;冷却到贝氏体转变开始温度以下20-200℃,可有效避免返温导致显微组织出现大量的先共析铁素体,从而提高钢轨的强度和韧性;之后将钢轨自然冷却至室温,可避免出现大量的马氏体,有效提高钢轨韧性。需要说明的是,所述贝氏体转变开始温度是将上述超低碳贝氏体钢制成铸坯,测定连续冷却下铸坯的贝氏体转变开始温度,测定方法可参考YB/T5128-1993《钢的连续冷却转变曲线图的测定方法(膨胀法)》。
优选地,步骤(2)中加热是指加热至1150-1250℃,保温2-3小时。
优选地,所述冷却的方法为空冷、雾冷或风冷中的一种或几种的组合,本领域技术人员可根据实际情况进行选择,能够达到预定的冷却效果即可。
优选地,所述热处理为回火处理,回火处理的温度为200-500℃,回火处理的保温时间为20-60小时,以促进部分贝氏体板条合并,稳定超低碳板条贝氏体组织,降低韧脆转变温度。
本发明的有益效果如下:
1、本发明的超低碳贝氏体钢和超低碳贝氏体钢轨通过控制超低的碳含量同时控制各合金元素的合理配比,有效地改善了贝氏体钢和贝氏体钢轨的焊接性能和低温韧性。
2、本发明通过采用超低的碳含量和合理的合金元素配比,结合精确的制备工艺,尤其是控制冷却工艺和回火工艺,获得了具有超低碳板条贝氏体组织的超低碳贝氏体钢轨,改善了贝氏体钢轨的焊接性能和低温韧性。本发明得到的超低碳贝氏体钢轨的综合性能得到明显提升,具体地,其抗拉强度≥800MPa,屈服强度≥700MPa,延伸率≥15%,冲击韧性≥200J/cm 2,韧脆转变温度低于-20℃;焊接热影响区的强度≥700MPa,热影响区的韧性≥100J/cm 2
3、本发明的超低碳贝氏体钢轨适用于时速大于250公里的高速铁路,对提高高速铁路的运营安全和舒适性具有重要的意义。
附图说明
下面结合附图对本发明的具体实施方式作进一步详细的说明。
图1示出实施例1所得超低碳贝氏体钢轨的显微组织照片。
图2示出实施例3所得超低碳贝氏体钢轨的显微组织照片。
图3示出实施例4所得超低碳贝氏体钢轨的显微组织照片。
具体实施方式
为了更清楚地说明本发明,下面结合优选实施例和附图对本发明做进一步的说明。本领域技术人员应当理解,下面所具体描述的内容是说明性的而非限制性的,不应以此限制本发明的保护范围。
表1示出了以下各实施例及对比例中贝氏体钢的组分含量(质量百分数),其中杂质是指不可避免的杂质。
表1各实施例及对比例中贝氏体钢的组分含量(质量百分数)
Figure PCTCN2019075365-appb-000001
实施例1
通过测定得该实施例制成的铸坯的贝氏体转变开始温度为550℃。测定方法参考YB/T5128-1993《钢的连续冷却转变曲线图的测定方法(膨胀法)》。
(1)按照表1中本实施例的配方,采用常规的炼钢工艺,由转炉或电炉进行冶炼和精炼,再采用连铸的方式进行铸造,得铸坯;
(2)将铸坯加热至1250℃,保温2小时,开坯,粗轧,精轧,得钢轨原型;
(3)通过空冷将钢轨原型踏面处以50℃/s的冷却速度冷却至350℃,然后自然冷却至室温,再在400℃之间回火20小时,得超低碳贝氏体钢轨。
如图1所示,其显微组织以超低碳板条贝氏体组织为主。
利用试验例1的方法测得该超低碳贝氏体钢轨的力学性能为:抗拉强度800-850MPa, 屈服强度700-775MPa,延伸率15-18%,冲击韧性300J/cm 2,韧脆转变温度-50℃,采用闪光对焊后,热影响区的抗拉强度为700-900MPa,冲击韧性为200J/cm 2
实施例2
通过测定得该实施例制成的铸坯的贝氏体转变开始温度为530℃。
(1)按照表1中本实施例的配方,采用常规的炼钢工艺,由转炉或电炉进行冶炼和精炼,再采用连铸的方式进行铸造,得铸坯;
(2)将铸坯加热至1200℃,保温2小时,开坯,粗轧,精轧,得钢轨原型;
(3)通过空冷将钢轨原型踏面处以30℃/s的冷却速度冷却至400℃,然后自然冷却至室温,再在460℃之间回火30小时,得超低碳贝氏体钢轨,该钢轨的显微组织以超低碳板条贝氏体组织为主。
测得该超低碳贝氏体钢轨的力学性能为:抗拉强度900-950MPa,屈服强度750-800MPa,延伸率15-20%,冲击韧性300J/cm 2,韧脆转变温度-40℃,采用闪光对焊后,热影响区的抗拉强度为850-980MPa,冲击韧性为160J/cm 2
实施例3
通过测定得该实施例制成的铸坯的贝氏体转变开始温度为510℃。
(1)按照表1中本实施例的配方,采用常规的炼钢工艺,由转炉或电炉进行冶炼和精炼,再采用连铸的方式进行铸造,得铸坯;
(2)将铸坯加热至1200℃,保温3小时,开坯,粗轧,精轧,得钢轨原型;
(3)通过雾冷将钢轨原型踏面处以25℃/s的冷却速度冷却至450℃,然后自然冷却至室温,再在400℃之间回火60小时,得超低碳贝氏体钢轨。
如图2所示,该钢轨的显微组织以超低碳板条贝氏体组织为主。
测得该超低碳贝氏体钢轨的力学性能为:抗拉强度875-925MPa,屈服强度775-800MPa,延伸率16-20%,冲击韧性280J/cm 2,韧脆转变温度-40℃,采用闪光对焊后,热影响区的抗拉强度为750-875MPa,冲击韧性为180J/cm 2
实施例4
通过测定得该实施例制成的铸坯的贝氏体转变开始温度为540℃。
(1)按照表1中本实施例的配方,采用常规的炼钢工艺,由转炉或电炉进行冶炼和精炼,再采用连铸的方式进行铸造,得铸坯;
(2)将铸坯加热至1150℃,保温3小时,开坯,粗轧,精轧,得钢轨原型;
(3)通过风冷将钢轨原型踏面处以10℃/s的冷却速度冷却至520℃,然后自然冷却至室温;再在200℃之间回火60小时,得超低碳贝氏体钢轨。
如图3所示,该钢轨的显微组织以超低碳板条贝氏体组织为主。
测得该超低碳贝氏体钢轨的力学性能为:抗拉强度850-900MPa,屈服强度700-750MPa,延伸率16-18%,冲击韧性280J/cm 2,韧脆转变温度-30℃,采用闪光对焊后,热影响区的抗拉强度为850-950MPa,冲击韧性为120J/cm 2
实施例5
通过测定得该实施例制成的铸坯的贝氏体转变开始温度为480℃。
(1)按照表1中本实施例的配方,采用常规的炼钢工艺,由转炉或电炉进行冶炼和 精炼,再采用连铸的方式进行铸造,得铸坯;
(2)将铸坯加热至1200℃,保温2小时,开坯,粗轧,精轧,得钢轨原型;
(3)通过雾冷将钢轨原型踏面处以2℃/s的冷却速度冷却至300℃,然后自然冷却至室温;再在500℃之间回火40小时,得超低碳贝氏体钢轨,该钢轨的显微组织以超低碳板条贝氏体组织为主。
测得该超低碳贝氏体钢轨的力学性能为:抗拉强度975-1050MPa,屈服强度900-950MPa,延伸率15-17%,冲击韧性200J/cm 2,韧脆转变温度-20℃,采用闪光对焊后,热影响区的抗拉强度为950-1100MPa,冲击韧性为100J/cm 2
对比例1
重复实施例1,区别在于,步骤(3)中加热后的钢轨原型直接自然冷却至室温。所得钢轨抗拉强度为400-500MPa。
对比例2
重复实施例2,区别在于,步骤(3)中没有将钢轨在460℃之间回火30小时。所得钢轨韧脆转变温度为-15℃;
对比例3
重复实施例5,区别在于,碳含量为0.18wt.%。所得钢轨冲击韧性为80J,韧脆转变温度为25℃。
对比例4
按照表1中本对比例的配方重复实施例2,区别在于碳含量不同,C+(Mn+Si)/6+Ni/15+(Cr+Mo+V)/50=0.86>0.8。所得钢轨冲击韧性为50J,韧脆转变温度为10℃,采用闪光对焊后,热影响区的抗拉强度为1300-1400MPa,冲击韧性为20J/cm 2,并出现焊接水平裂纹。
试验例1
力学性能测试试验
通过万能拉伸试验机,采用标准拉伸试样,根据相关国家标准的规定,分别测定了各实施例及对比例制备的钢轨试样的力学性能。通过测试结果可以看出,本发明得到的超低碳贝氏体钢轨的力学性能得到明显提升,具体地,其抗拉强度≥800MPa,屈服强度≥700MPa,延伸率≥15%,冲击韧性≥200J/cm 2,韧脆转变温度低于-20℃;焊接热影响区的强度≥700MPa,热影响区的韧性≥100J/cm 2,具有高强度、高韧性的良好性能。
显然,本发明的上述实施例仅仅是为清楚地说明本发明所作的举例,而并非是对本发明的实施方式的限定,对于所属领域的普通技术人员来说,在上述说明的基础上还可以做出其它不同形式的变化或变动,这里无法对所有的实施方式予以穷举,凡是属于本发明的技术方案所引伸出的显而易见的变化或变动仍处于本发明的保护范围之列。

Claims (10)

  1. 一种超低碳贝氏体钢,其特征在于,其组成包含:
    C:0.01-0.10wt%,Mn:1.8-2.3wt%,Si:0.3-1.5wt%,Cr:0.1-0.6wt%,Ni:0.5-2.0wt%,Mo:0.1-0.5wt%,V:0.01-0.25wt%;其余为Fe和不可避免的杂质元素,显微组织主要为超低碳板条贝氏体组织;
    且各元素的含量满足以下关系式:C+(Mn+Si)/6+Ni/15+(Cr+Mo+V)/50≤0.8。
  2. 根据权利要求1所述的一种超低碳贝氏体钢,其特征在于,其组成包含:
    C:0.01-0.08wt%,Mn:2.0-2.1wt%,Si:0.8-1.2wt%,Cr:0.2-0.5wt%,Ni:1.0-1.2wt%,Mo:0.3-0.4wt%,V:0.04-0.08wt%;其余为Fe和不可避免的杂质元素,显微组织主要为超低碳板条贝氏体组织;
    且各元素的含量满足以下关系式:C+(Mn+Si)/6+Ni/15+(Cr+Mo+V)/50≤0.8
  3. 一种超低碳贝氏体钢轨,其特征在于,由权利要求1所述的超低碳贝氏体钢制成。
  4. 一种如权利要求2所述的超低碳贝氏体钢轨在时速大于250公里的高速铁路中的应用。
  5. 一种超低碳贝氏体钢轨的制备方法,其特征在于,包括以下步骤:
    (1)将具有权利要求1组成的超低碳贝氏体钢的原料采用炼钢工艺进行冶炼、铸造,得铸坯;
    (2)将铸坯加热,开坯,粗轧,精轧,得钢轨原型;
    (3)将钢轨原型踏面处以恒定冷速连续冷却至贝氏体转变开始温度以下,然后自然冷却至室温,进行热处理,得超低碳贝氏体钢轨。
  6. 根据权利要求4所述的超低碳贝氏体钢轨的制备方法,其特征在于,步骤(3)中所述恒定冷速为2-50℃/s。
  7. 根据权利要求4所述的超低碳贝氏体钢轨的制备方法,其特征在于,步骤(3)将钢轨原型踏面处以恒定冷速连续冷却至贝氏体转变开始温度以下20-200℃,然后自然冷却至室温,得超低碳贝氏体钢轨。
  8. 根据权利要求4所述的超低碳贝氏体钢轨的制备方法,其特征在于,步骤(2)中加热是指加热至1150-1250℃,保温2-3小时。
  9. 根据权利要求4所述的超低碳贝氏体钢轨的制备方法,其特征在于,所述冷却的方法为空冷、雾冷或风冷中的一种或几种。
  10. 根据权利要求4所述的超低碳贝氏体钢轨的制备方法,其特征在于,步骤(3)中所述热处理为回火处理,回火处理的温度为200-500℃,回火处理的保温时间为20-60小时。
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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3522613B2 (ja) * 1999-11-26 2004-04-26 新日本製鐵株式会社 耐ころがり疲労損傷性、耐内部疲労損傷性、溶接継ぎ手特性に優れたベイナイト系レールおよびその製造法
CN102534387A (zh) * 2011-12-12 2012-07-04 中国铁道科学研究院金属及化学研究所 1500MPa级高强韧性贝氏体/马氏体钢轨及其制造方法
CN103160736A (zh) * 2011-12-14 2013-06-19 鞍钢股份有限公司 一种高强度贝氏体钢轨及其热处理工艺
CN103409694A (zh) * 2013-08-09 2013-11-27 内蒙古包钢钢联股份有限公司 一种低碳微合金化贝氏体钢轨用钢及制造方法
CN103789699A (zh) * 2012-11-03 2014-05-14 无锡市森信精密机械厂 一种辙叉心轨用贝氏体钢的制备工艺
CN103805903A (zh) * 2012-11-03 2014-05-21 无锡市森信精密机械厂 一种辙叉心轨用贝氏体钢

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1166804C (zh) * 1998-12-07 2004-09-15 清华大学 铁道辙叉专用超强高韧可焊接空冷鸿康贝氏体钢及制造方法
JP2000199041A (ja) * 1999-01-07 2000-07-18 Nippon Steel Corp 耐ころがり疲労損傷性、耐内部疲労損傷性に優れたベイナイト系レ―ル
CN1721565A (zh) * 2004-07-13 2006-01-18 铁道科学研究院 含有稳定残余奥氏体的全贝氏体钢辙叉及其制造工艺
CN100408712C (zh) * 2005-04-18 2008-08-06 河南省强力机械有限公司 准贝氏体钢
CN101921971B (zh) * 2010-09-08 2013-03-13 北京特冶工贸有限责任公司 曲线和重载钢轨用贝氏体钢和贝氏体钢轨及其生产方法
CN105316596B (zh) * 2014-06-13 2017-06-16 北京交通大学 一种超低磷贝氏体钢及其贝氏体钢轨
CN105063511B (zh) * 2015-08-14 2017-03-22 武汉钢铁(集团)公司 中厚板轧机轧制超低碳贝氏体类薄规格钢板及其生产方法
CN106893832B (zh) * 2015-12-18 2018-08-10 北京交通大学 一种无碳化物贝/马复相钢的bq&p热处理工艺
CN107326302B (zh) * 2017-05-26 2018-10-19 北京交通大学 一种耐蚀贝氏体钢、钢轨及制备方法
CN107130171B (zh) * 2017-05-26 2018-12-25 北京交通大学 一种中低碳高强高韧耐蚀贝氏体钢、钢轨及制备方法

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3522613B2 (ja) * 1999-11-26 2004-04-26 新日本製鐵株式会社 耐ころがり疲労損傷性、耐内部疲労損傷性、溶接継ぎ手特性に優れたベイナイト系レールおよびその製造法
CN102534387A (zh) * 2011-12-12 2012-07-04 中国铁道科学研究院金属及化学研究所 1500MPa级高强韧性贝氏体/马氏体钢轨及其制造方法
CN103160736A (zh) * 2011-12-14 2013-06-19 鞍钢股份有限公司 一种高强度贝氏体钢轨及其热处理工艺
CN103789699A (zh) * 2012-11-03 2014-05-14 无锡市森信精密机械厂 一种辙叉心轨用贝氏体钢的制备工艺
CN103805903A (zh) * 2012-11-03 2014-05-21 无锡市森信精密机械厂 一种辙叉心轨用贝氏体钢
CN103409694A (zh) * 2013-08-09 2013-11-27 内蒙古包钢钢联股份有限公司 一种低碳微合金化贝氏体钢轨用钢及制造方法

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