CN111254349A - Steel for single-track turnout with extremely low yield ratio and production method thereof - Google Patents

Steel for single-track turnout with extremely low yield ratio and production method thereof Download PDF

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Publication number
CN111254349A
CN111254349A CN201911205856.1A CN201911205856A CN111254349A CN 111254349 A CN111254349 A CN 111254349A CN 201911205856 A CN201911205856 A CN 201911205856A CN 111254349 A CN111254349 A CN 111254349A
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China
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steel
yield ratio
low yield
turnout
extremely low
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CN201911205856.1A
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Chinese (zh)
Inventor
唐春霞
邓伟
楚觉非
崔强
王军
孟令明
尹雨群
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Nanjing Iron and Steel Co Ltd
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Nanjing Iron and Steel Co Ltd
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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
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226—Hot rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
    • 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
    • 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
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
    • 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
    • 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
    • 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
    • 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
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/005—Ferrite
    • 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
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/009—Pearlite

Abstract

The invention discloses a steel with extremely low yield ratio for a single-track turnout, which comprises the following chemical element components in percentage by weight: c: 0.02 to 0.16%, Si: 0.15 to 0.50%, Mn: 0.80-1.80%, P: 0.004-0.015%, S: less than or equal to 0.005 percent, Nb: 0.010-0.050%, Ti: 0.008-0.020%, Ni: 0.25-0.45%, Cr: 0.40-0.60%, Cu: 0.25-0.45%, Al: 0.015-0.050%, and the balance of Fe and impurities; the invention obtains the structure consisting of soft phase ferrite and hard phase pearlite with moderate grain size by utilizing the tempering process, thereby obtaining the steel plate for the monorail turnout with extremely low yield ratio.

Description

Steel for single-track turnout with extremely low yield ratio and production method thereof
Technical Field
The invention relates to a steel with extremely low yield ratio for a single-track turnout and a production method thereof.
Background
The straddle type monorail transit has the characteristics of small occupied area, low noise, less shielded light, strong terrain adaptability and the like. The new light rail line in Chongqing city is the first straddle type single rail technology adopted in China. The structure and operation control mode of the turnout in the straddle type monorail system are completely different from those of a conventional wheel-rail traffic system, and the turnout is complex in structure and various in form.
The basic structure of the single-track switch is to ensure the safety and stability of the train in the course of changing the track, the straddle type single-track switch adopts a beam structure similar to a track beam, consists of a group of mutually connected steel box beams with rotatable joints, and is mainly divided into 3 parts of a switch structure, a switch driving system and a signal control system. The single-rail turnout consists of a turnout beam, a finger-shaped joint group, a cross hinge, a tail shaft device and the like.
The turnout beam is a box beam formed by welding steel plates, the top surface of the turnout beam is a running surface for running of a bearing wheel of a vehicle, and the side surface of the turnout beam is provided with a guide surface and a stabilizing surface for running of a horizontal wheel of the vehicle.
The single-rail turnout is important equipment for realizing train turnout operation, and the single-rail turnout needs to have enough rigidity and fatigue strength to bear the repeated action of vehicle operation loads such as twisting force, impact force and the like; and the single-rail turnout is of a steel box girder structure, is used in an open air switching way, and has the high-efficiency dustproof, moistureproof, acid and rain erosion resistant capability and anticorrosion, insulation and power-off safety protection measures.
The single-track turnout steel sheet has strict requirements on the uniformity of the structure and the components. On one hand, high standard and high requirement is provided for smelting, on the other hand, alloy elements such as chromium, nickel, copper and the like are added to improve the atmospheric corrosion resistance of the steel plate, a proper amount of micro-alloying elements are added to improve the low-temperature impact toughness, and low-carbon design is matched to facilitate weldability. On the basis of component design, a proper rolling and heat treatment process is matched, so that the steel plate is ensured to have stable and good comprehensive use performance and welding processing performance.
CN102839268A discloses a heat treatment method of bainite switch rail to make switch rail have good straightness. However, the turnout steel in the patent is a steel grade designed by high-strength high-carbon components with the strength of more than 1000MPa, and has high carbon equivalent and poor welding performance; the-40 ℃ low-temperature impact toughness of the turnout steel in the patent is between 55 and 99J, and does not reach the level that the-40 ℃ low-temperature impact toughness is more than or equal to 200J; the turnout steel yield ratio in the patent is between 0.79 and 0.83, and the yield ratio is not more than 0.75 while maintaining high low-temperature impact toughness.
CN104894484A discloses a method for manufacturing steel for railway switch. However, the turnout steel in the patent is a high-strength high-carbon high-silicon high-chromium composition design, and although a heat treatment method is adopted to improve the phenomenon of performance nonuniformity caused by nonuniform grain size due to composition segregation, the process method needs to carry out multiple times of heating and heat preservation treatment, is not simple and easy to implement, and is not beneficial to high-efficiency organization and mass production.
Disclosure of Invention
The invention aims to solve the technical problem that aiming at the defects in the prior art, the invention provides the steel for the monorail turnout with the extremely low yield ratio and the production method thereof.
The technical scheme for solving the technical problems is as follows: the steel for the single-track turnout with the extremely low yield ratio comprises the following chemical element components in percentage by weight: c: 0.02 to 0.16%, Si: 0.15 to 0.50%, Mn: 0.80-1.80%, P: 0.004-0.015%, S: less than or equal to 0.005 percent, Nb: 0.010-0.050%, Ti: 0.008-0.020%, Ni: 0.25-0.45%, Cr: 0.40-0.60%, Cu: 0.25-0.45%, Al: 0.015-0.050%, and the balance of Fe and impurities.
The invention further defines the scheme:
the chemical element components comprise the following components in percentage by weight: c: 0.10-0.15%, Si: 0.30-0.40%, Mn: 0.80-1.20%, P: 0.004-0.009%, S: less than or equal to 0.004%, Nb: 0.016-0.019%, Ti: 0.008-0.010%, Ni: 0.38-0.42%, Cr: 0.40-0.46%, Cu: 0.25-0.27%, Al: 0.015-0.021%, and Fe and impurities for the rest.
The chemical element components comprise the following components in percentage by weight: c: 0.08-0.13%, Si: 0.15-0.20%, Mn: 1.10-1.22%, P: 0.009-0.012%, S: less than or equal to 0.003 percent, Nb: 0.010-0.013%, Ti: 0.013-0.018%, Ni: 0.25-0.27%, Cr: 0.45-0.55%, Cu: 0.28-0.35%, Al: 0.018-0.036%, and the balance of Fe and impurities.
The chemical element components comprise the following components in percentage by weight: c: 0.02 to 0.06%, Si: 0.15-0.19%, Mn: 1.20-1.30%, P: 0.007-0.009%, S: less than or equal to 0.002%, Nb: 0.02 to 0.025%, Ti: 0.015-0.018%, Ni: 0.30-0.35%, Cr: 0.42-0.46%, Cu: 0.30-0.38%, Al: 0.021-0.038%, and Fe and impurities for the rest.
The invention also provides a production method for the single-track turnout steel with the extremely low yield ratio, which comprises the following steps:
(1) heating a casting blank: putting the casting blank into a furnace to heat, wherein the austenitizing temperature is 1150-1250 ℃;
(2) rolling of
The rolling is completed in two stages:
rolling in the first stage: the rough rolling temperature is 1000-;
rolling in the second stage: the finish rolling temperature is 950-;
(3) the heat treatment process comprises the following steps: tempering treatment is carried out, the tempering temperature is 450-600 ℃, the tempering heat preservation time is 20-50min, and then the tempering treatment is carried out along with air cooling.
The invention has the beneficial effects that:
the invention can eliminate the problem that TMCP can not eliminate banded structures formed by component segregation in the casting blank by a simple heat treatment method, and the formed structures are refined and tend to be uniform;
after tempering treatment, a structure consisting of soft phase ferrite and hard phase pearlite is obtained, wherein part of ferrite obviously has a drawing trend along a rolling direction, and the deformed Bo-pie structure enables effective grain size to be refined and is beneficial to improving strength; meanwhile, the size of the crystal grains is moderate, the size is 10-13.5 mu m, the grain size is 9.5-10.0 grade, the proper size of the crystal grains is beneficial to obtaining proper obdurability matching, the yield strength lifting amplitude is lower than the tensile strength, so that a low yield ratio steel plate is beneficial to obtaining, an extremely low yield ratio is obtained, the yield ratio is less than or equal to 0.75, and a certain margin is provided, so that the strength reserve of the steel plate is large, and the structure is safer.
Drawings
FIG. 1 shows the typical structure morphology of the steel plate for the single-track switch obtained after the tempering treatment in example 1 under a metallographic microscope.
Detailed Description
The chemical element compositions in percentage by weight of the steel for the monorail turnout with the extremely low yield ratio are shown in the table 1.
The production method for the steel with the extremely low yield ratio for the single-track turnout comprises the following steps:
(1) heating a casting blank: putting the casting blank into a furnace to heat, wherein the austenitizing temperature is 1150-1250 ℃;
(2) rolling of
The rolling is completed in two stages:
rolling in the first stage: the rough rolling temperature is 1000-;
rolling in the second stage: the finish rolling temperature is 950-;
(3) the heat treatment process comprises the following steps: tempering treatment is carried out, the tempering temperature is 450-600 ℃, the tempering heat preservation time is 20-50min, and then the tempering treatment is carried out along with air cooling.
Fig. 1 shows a typical structure morphology of a steel plate for a single-track switch obtained after tempering treatment in example 1 under a metallographic microscope, and it can be found that the structure is uniform, the grain size is moderate, and the yield ratio of the steel plate can be reduced while the toughness matching is favorably satisfied.
Table 2 shows the process parameters for a single track turnout very low yield ratio steel production process.
The mechanical tensile properties after tempering are shown in table 3.
TABLE 1 chemical composition in wt% of inventive examples
Examples C Si Mn P S Nb Ti Cr Ni Cu Alt
1 0.15 0.38 0.80 0.009 0.002 0.019 0.008 0.46 0.38 0.27 0.021
2 0.09 0.15 1.20 0.012 0.003 0.010 0.018 0.55 0.27 0.35 0.036
3 0.06 0.22 1.20 0.009 0.002 0.025 0.018 0.46 0.35 0.38 0.038
4 0.13 0.45 0.90 0.009 0.003 0.019 0.008 0.46 0.35 0.27 0.045
5 0.07 0.20 1.20 0.012 0.002 0.028 0.018 0.55 0.27 0.35 0.036
Table 2 process parameters of the examples of the invention
Figure BDA0002296928020000041
Table 3 table of performance of the embodiment of the present invention
Examples ReL/MPa Rm/MPa A/％ Yield ratio Impact test (-40 deg.C.)/J
1 378 525 26 0.72 256 254 213
2 466 675 22 0.69 247 249 255
3 386 529 22.5 0.73 256 260 287
4 443 624 22.5 0.71 243 259 287
5 390 534 22 0.73 336 327 315
It can be seen that the mechanical properties of examples 1-5 all meet the requirements of users, the yield ratio is less than or equal to 0.75, the elongation is greater than or equal to 21%, the average value of the impact properties at minus 40 ℃ is greater than 200J, and especially example 5 has excellent low-temperature impact toughness and lower yield ratio. The heat treatment method is simple and easy to implement, and the comprehensive performance of the material is improved.
In addition to the above embodiments, the present invention may have other embodiments. All technical solutions formed by adopting equivalent substitutions or equivalent transformations fall within the protection scope of the claims of the present invention.

Claims (8)

1. A steel with extremely low yield ratio for a monorail turnout is characterized in that: the chemical element components of the material comprise the following components in percentage by weight: c: 0.02 to 0.16%, Si: 0.15 to 0.50%, Mn: 0.80-1.80%, P: 0.004-0.015%, S: less than or equal to 0.005 percent, Nb: 0.010-0.050%, Ti: 0.008-0.020%, Ni: 0.25-0.45%, Cr: 0.40-0.60%, Cu: 0.25-0.45%, Al: 0.015-0.050%, and the balance of Fe and impurities.
2. The steel for a single-track turnout with an extremely low yield ratio according to claim 1, wherein: the chemical element components of the material comprise the following components in percentage by weight: c: 0.10-0.15%, Si: 0.30-0.40%, Mn: 0.80-1.20%, P: 0.004-0.009%, S: less than or equal to 0.004%, Nb: 0.016-0.019%, Ti: 0.008-0.010%, Ni: 0.38-0.42%, Cr: 0.40-0.46%, Cu: 0.25-0.27%, Al: 0.015-0.021%, and Fe and impurities for the rest.
3. The steel for a single-track turnout with an extremely low yield ratio according to claim 1, wherein: the chemical element components of the material comprise the following components in percentage by weight: c: 0.08-0.13%, Si: 0.15-0.20%, Mn: 1.10-1.22%, P: 0.009-0.012%, S: less than or equal to 0.003 percent, Nb: 0.010-0.013%, Ti: 0.013-0.018%, Ni: 0.25-0.27%, Cr: 0.45-0.55%, Cu: 0.28-0.35%, Al: 0.018-0.036%, and the balance of Fe and impurities.
4. The steel for a single-track turnout with an extremely low yield ratio according to claim 1, wherein: the chemical element components of the material comprise the following components in percentage by weight: c: 0.02 to 0.06%, Si: 0.15-0.19%, Mn: 1.20-1.30%, P: 0.007-0.009%, S: less than or equal to 0.002%, Nb: 0.02 to 0.025%, Ti: 0.015-0.018%, Ni: 0.30-0.35%, Cr: 0.42-0.46%, Cu: 0.30-0.38%, Al: 0.021-0.038%, and Fe and impurities for the rest.
5. A method for producing a very low yield ratio steel for a single track switch according to any one of claims 1 to 4, characterized in that: the method specifically comprises the processes of heating, rolling and heat treatment of a casting blank.
6. A method for producing a single track turnout steel with a very low yield ratio according to claim 5, wherein: the austenitizing temperature of the casting blank is 1150-1250 ℃ after the casting blank is heated.
7. A method for producing a single track turnout steel with a very low yield ratio according to claim 5, wherein: the rolling is completed in two stages: rolling in the first stage: the rough rolling temperature is 1000-; rolling in the second stage: the finish rolling temperature is 950-.
8. A method for producing a single track turnout steel with a very low yield ratio according to claim 5, wherein: the heat treatment process is tempering treatment, the tempering temperature is 450-600 ℃, the tempering heat preservation time is 20-50min, and then the tempering heat preservation process is carried out along with air cooling.
CN201911205856.1A 2019-11-29 2019-11-29 Steel for single-track turnout with extremely low yield ratio and production method thereof Withdrawn CN111254349A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112301205A (en) * 2020-10-19 2021-02-02 攀钢集团攀枝花钢铁研究院有限公司 Pearlite steel rail with high yield ratio and preparation method thereof

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112301205A (en) * 2020-10-19 2021-02-02 攀钢集团攀枝花钢铁研究院有限公司 Pearlite steel rail with high yield ratio and preparation method thereof

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