CN116855831A - Quenched and tempered steel plate with low yield ratio, high strength and low temperature toughness for hydropower and production method thereof - Google Patents

Quenched and tempered steel plate with low yield ratio, high strength and low temperature toughness for hydropower and production method thereof Download PDF

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CN116855831A
CN116855831A CN202310870643.0A CN202310870643A CN116855831A CN 116855831 A CN116855831 A CN 116855831A CN 202310870643 A CN202310870643 A CN 202310870643A CN 116855831 A CN116855831 A CN 116855831A
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steel plate
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胡战
陈建恩
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Baosteel Zhanjiang Iron and Steel Co Ltd
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Baosteel Zhanjiang 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
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/18—Hardening; Quenching with or without subsequent tempering
    • 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
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/004—Heat treatment of ferrous alloys containing Cr and Ni
    • 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
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/005—Heat treatment of ferrous alloys containing Mn
    • 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
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/008—Heat treatment of ferrous alloys containing Si
    • 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
    • C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
    • 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
    • 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
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • 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
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
    • 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
    • C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
    • 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
    • C22C38/54—Ferrous alloys, e.g. steel alloys containing chromium with nickel with boron

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  • Metallurgy (AREA)
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  • Physics & Mathematics (AREA)
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  • Crystallography & Structural Chemistry (AREA)
  • Heat Treatment Of Steel (AREA)

Abstract

The invention discloses a quenched and tempered steel plate with low yield ratio, high strength and low temperature toughness, which is prepared by smelting the following components in percentage by mass: c:0.05 to 0.08 percent, si:0.15 to 0.25 percent, mn:1.43 to 1.53 percent, P is less than or equal to 0.012 percent, S is less than or equal to 0.002 percent, cu: 0.06-0.10%, ni:0.15 to 0.27 percent, cr:0.12 to 0.20 percent, mo:0.10 to 0.20 percent, V:0.02 to 0.04 percent, ti:0.007 to 0.015 percent, B:0.0008 to 0.0014 percent, al:0.04 to 0.06 percent, ca:0.0005 to 0.0025 percent, the balance being Fe and unavoidable impurities, and the impurity elements should be as low as possible, and satisfy the following conditions: ceq (%) = C+Si/24+Mn/6+Ni/40+Cr/5+Mo/4+V/14 0.39.ltoreq.Ceq (%). The invention also discloses a method for producing the steel plate through smelting, casting, heating, heat preservation, rolling, air cooling, shot blasting, quenching and tempering, and the produced steel plate has better comprehensive performance and can meet the requirements of hydropower steel with higher requirements.

Description

Quenched and tempered steel plate with low yield ratio, high strength and low temperature toughness for hydropower and production method thereof
Technical Field
The invention relates to the technical field of metallurgy, in particular to a quenched and tempered low-temperature ductile steel plate for hydropower and a manufacturing method thereof.
Background
In recent years, with the intensive development of clean energy, a large number of pumped storage power stations with peak clipping and valley filling capabilities need to be built. Hydropower station pressure steel pipes, steel branch pipes and spiral cases used at key parts of a pumped storage power station are required to have high comprehensive mechanical properties and good uniformity of cross sections along thickness, a large amount of hydropower station 07MnMoVR with strength grade reaching 600MPa is required to be used, and the steel is required to be delivered in a tempering heat treatment state of off-line quenching and tempering according to the specification in national standard GB 19189-2011. In order to meet the requirements of safe use of materials, the steel plate needs to have high strength and low yield ratio. The yield ratio refers to the ratio of the yield point (yield strength) to the tensile strength of a material, when the yield ratio is small, the steel firstly reaches the yield strength and the strength is continuously developed when the steel is subjected to deformation force, the deformation is visible to naked eyes, the deformation is a precursor of structural damage, the deformation can be found and prevented in advance, and the safety coefficient is high in the service process.
At present, the yield ratio of the domestically produced quenched and tempered high-strength steel plate is generally higher, and the steel plate has defects in chemical components, production process and mechanical properties.
Chinese patent CN102643960a discloses a heat treatment method for improving mechanical properties of low-carbon quenched and tempered steel, wherein the yield ratio of the steel plate is less than 0.90, but the ni=0.3-1.2%, cu=0.3-1.2%, cr=0.3-0.8%, mo=0.3-0.8% of the steel plate is high alloy steel, and the manufacturing cost is uneconomical. Chinese patent CN103540842a discloses a method for producing Cr-free high strength quenched and tempered steel plate for spherical tank, the yield ratio of the steel plate is less than 0.95, the yield ratio is higher and Mo: the content of 0.3 to 0.40 percent is higher, and the manufacturing cost is uneconomical. Chinese patent CN103276314A discloses a low yield ratio high toughness X80 pipeline steel plate and a manufacturing method thereof, wherein the yield ratio (Rt 0.5/Rm) is less than or equal to 0.82, but the tempering temperature is 350-550 ℃, the production process requirements of the tempering high strength steel plate for the pressure vessel in the national standard GB19189-2011 cannot be met, the steel plate is delivered in a quenching and tempering heat treatment state, and the tempering temperature is not lower than 600 ℃. Chinese patent CN108728729A discloses a high-strength quenched and tempered container steel with low yield ratio and a production method thereof, wherein the yield ratio of a produced steel plate is less than or equal to 0.85, but the low-temperature toughness only reaches the single value of impact energy of minus 20 ℃ and is more than or equal to 100J, the lower temperature requirement cannot be met, the steel does not contain Mo alloy elements and the V content is 0.01-0.08%, and the requirement of the national standard GB19189-2011 on 07MnMoVR components cannot be met. Chinese patent CN107604248A discloses a high-strength Q500GJD quenched and tempered steel plate for building structure and a manufacturing method thereof, wherein the yield ratio is less than or equal to 0.82, but the steel plate can only meet the V-shaped impact energy at-20 ℃ of more than or equal to 100J and cannot meet the lower temperature requirement.
Disclosure of Invention
The invention aims to provide a quenched and tempered steel plate with low yield ratio, high strength and low temperature toughness for water and electricity and a manufacturing method thereof, wherein the yield strength of the steel plate is more than or equal to 570MPa, the tensile strength is more than or equal to 640MPa, the elongation is more than or equal to 20%, the yield ratio is less than or equal to 0.92, the Charpy notch impact power Kv2 at-40 ℃ is more than or equal to 200J, and the Charpy notch impact power Kv2 at-40 ℃ is more than or equal to 150J after the steel plate is subjected to 5% strain and aging at 250 ℃ for 1 hour.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
in a first aspect, the invention provides a quenched and tempered steel plate with low yield ratio, high strength and low temperature toughness, which is prepared by smelting the following components in percentage by mass: c:0.05 to 0.08 percent, si:0.15 to 0.25 percent, mn:1.43 to 1.53 percent, P is less than or equal to 0.012 percent, S is less than or equal to 0.002 percent, cu: 0.06-0.10%, ni:0.15 to 0.27 percent, cr:0.12 to 0.20 percent, mo:0.10 to 0.20 percent, V:0.02 to 0.04 percent, ti:0.007 to 0.015 percent, B:0.0008 to 0.0014 percent, al:0.04 to 0.06 percent, ca:0.0005 to 0.0025 percent, and the balance of Fe and unavoidable impurities, and satisfies the following conditions: ceq (%) = C+Si/24+Mn/6+Ni/40+Cr/5+Mo/4+V/14 0.39.ltoreq.Ceq (%).
Preferably, the quenched and tempered steel plate with low yield ratio, high strength and low temperature toughness is prepared by smelting the following components in percentage by mass: c:0.05 to 0.071 percent, si:0.15 to 0.233 percent, mn:1.43 to 1.503 percent, P is less than or equal to 0.012 percent, S is less than or equal to 0.002 percent, cu: 0.06-0.07%, ni:0.15 to 0.243 percent, cr:0.12 to 0.171 percent, mo:0.10 to 0.172 percent, V:0.02 to 0.039 percent, ti:0.007 to 0.013 percent, B:0.0008 to 0.0013 percent, al:0.04 to 0.054 percent, ca:0.0005 to 0.0016 percent, and the balance of Fe and unavoidable impurities, and satisfies the following conditions: ceq (%) = C+Si/24+Mn/6+Ni/40+Cr/5+Mo/4+V/14 0.39.ltoreq.Ceq (%).
Further preferably, the quenched and tempered steel plate with low yield ratio, high strength and low temperature toughness is prepared by smelting the following components in percentage by mass: c:0.059 to 0.071 percent, si: 0.195-0.233%, mn:1.445 to 1.503 percent, P is less than or equal to 0.008 percent, S is less than or equal to 0.0007 percent, cu: 0.06-0.07%, ni:0.221 to 0.243 percent, cr:0.149 to 0.171 percent, mo:0.164 to 0.172 percent, V: 0.031-0.039%, ti: 0.011-0.013%, B:0.0010 to 0.0013 percent, al:0.04 to 0.054 percent, ca:0.0013 to 0.0016 percent, and the balance of Fe and unavoidable impurities, and satisfies the following conditions: ceq (%) is more than or equal to 0.394 and is less than or equal to C+Si/24+Mn/6+Ni/40+Cr/5+Mo/4+V/14 and is less than or equal to 0.412.
Further preferably, the quenched and tempered steel plate with low yield ratio, high strength and low temperature toughness is prepared by smelting the following components in percentage by mass: c:0.059 to 0.066 percent, si: 0.195-0.208%, mn:1.445 to 1.480 percent, P is less than or equal to 0.01 percent, S is less than or equal to 0.0016 percent, cu:0.06 to 0.067 percent, ni:0.221 to 0.232 percent, cr:0.149 to 0.167 percent, mo:0.164 to 0.166 percent, V: 0.031-0.037%, ti: 0.011-0.012%, B:0.0010 to 0.0011 percent, al:0.04 to 0.053 percent, ca:0.0013 to 0.0015 percent, and the balance of Fe and unavoidable impurities, and satisfies the following conditions: ceq (%) is more than or equal to 0.396 and C+Si/24+Mn/6+Ni/40+Cr/5+Mo/4+V/14 is more than or equal to 0.412.
Further preferably, the quenched and tempered steel plate with low yield ratio, high strength and low temperature toughness is prepared by smelting the following components in percentage by mass: c:0.060 to 0.066 percent, si:0.199 to 0.208 percent, mn:1.451 to 1.480 percent, P is less than or equal to 0.009 percent, S is less than or equal to 0.00106 percent, cu: 0.066-0.067%, ni: 0.225-0.232%, cr:0.154 to 0.167 percent, mo: 0.165-0.166%, V:0.034 to 0.037 percent, ti:0.012%, B:0.0011%, al:0.049 to 0.053 percent, ca:0.0014 to 0.0015 percent, and the balance of Fe and unavoidable impurities, and satisfies the following conditions: ceq (%) is more than or equal to 0.396 and C+Si/24+Mn/6+Ni/40+Cr/5+Mo/4+V/14 is more than or equal to 0.400.
C: the content of C is not too low or too high for the hardenability, strength and low-temperature toughness of the steel. With the increase of the C content in the steel, the hardenability of the steel and the tensile strength and the yield strength of the steel after quenching are increased, but the elongation and the notch impact toughness are reduced, and the C content is controlled to be 0.05-0.08% in order to have good low-temperature toughness.
Si: is the main deoxidizer and can improve the strength of the steel plate, but Si seriously impairs the low-temperature toughness and elongation of the steel plate, so the Si content in the steel should be controlled as low as possible, and the Si content is about 0.20 percent, namely 0.15 to 0.25 percent in consideration of the economy and operability of the steelmaking process.
Mn: the alloy element not only improves the strength of the steel plate, but also has the function of improving the low-temperature toughness of the steel plate; however, mn is easy to segregate in the solidification process of molten steel, and particularly when the Mn content is high, casting operation is difficult, and conjugated segregation phenomenon is easy to occur with C, P, S and other elements; therefore, the Mn content is suitably 1.43% to 1.53%.
P: as harmful inclusions in steel have great damaging effect on the mechanical properties of steel, especially low-temperature impact toughness and elongation, the lower the theoretical requirement is, the better; however, in view of steel-making operability and steel-making cost, the P content needs to be controlled to 0.012% or less.
S: harmful elements in the steel have a great damaging effect on the low-temperature toughness of the steel, and meanwhile S is also a main element generating hot brittleness in the hot rolling process, and theoretically, the lower the requirement is, the better the lower the requirement is; however, in consideration of steel-making operability, steel-making cost and a smooth material flow principle, the S content needs to be controlled to be less than or equal to 0.002%.
Cu: the method has little influence on the strength and toughness performance of the steel plate, but has strong composite strengthening and toughening effects by matching with other alloy elements and micro-alloy elements, and the Cu content is controlled to be 0.06-0.10% from the viewpoint of production economy.
Ni: the alloy is an austenite stabilizing element, has the tendency of inhibiting ferrite covalent bonds under the low-temperature condition, reduces the P-N force of dislocation movement, promotes dislocation slip, improves the low-temperature toughness of the steel plate, is an effective hardenability element, and can reduce the C content by adding Ni, wherein the Ni is a very noble element, and the Ni content is controlled to be 0.15-0.27% from the aspect of cost performance.
Cr: the steel plate strength and the hardenability of the steel plate can be improved, the C content can be reduced by adding Cr, but the low-temperature impact toughness of the steel plate is deteriorated by the Cr, and the Cr content is controlled to be 0.12-0.20% by comprehensively considering.
Mo: the addition of Mo can greatly improve the hardenability of the steel plate and promote the formation of martensite/bainite, and the addition of Ni can reduce the C content, but Mo deteriorates the low-temperature impact toughness of the quenched and tempered steel plate; meanwhile, mo is a heat-strengthening element, so that the high-temperature strength, high-temperature lasting strength and creep strength of the steel plate can be effectively improved, SR embrittlement is effectively resisted, the low-temperature toughness of the steel plate is ensured after the steel plate is strained and at high temperature, the Mo of the hydroelectric steel 07MnMoVR in the national standard GB19189-2011 is required to be 0.10-0.30%, and the content of Mo is comprehensively considered to be controlled to be 0.10-0.20%.
V: is an tempering softening resistant element, and V (C, N) particles are separated out in the tempering process, so that the width of a tempering platform is widened, and the toughness matching of the quenched and tempered steel plate is ensured; v (C, N) and ferrite have low-energy orientation relation, so that austenite crystal nucleation is promoted, a steel plate microstructure is refined, the impact toughness of the steel plate is improved, and the V of the hydroelectric steel 07MnMoVR in the national standard GB19189-2011 is required to be 0.02-0.05%, so that the V component is designed to be 0.02-0.04%.
Ti: the austenite grain growth in the heating, rolling and welding thermal cycle process is inhibited, the impact toughness of the steel plate is improved, ti and C are combined and finely dispersed and separated out, and the strength of the steel plate is improved, so that the optimal control range of the Ti content is 0.007-0.015%.
B: is a strong hardenability element, can obviously improve the hardenability of steel, ensures the hardenability of a thick steel plate, and ensures that the quenched steel plate obtains a martensitic structure with coarse grains and flat grain boundaries, but the structure is unfavorable for low-temperature toughness, so the optimal control range of the B content is 0.0008-0.0014 percent.
Al: is the main deoxidizing element in steel, is favorable for refining grains, and is generally contained in certain amount. The Al content is controlled to be 0.04-0.06%.
Ca: on one hand, the molten steel can be further purified, and on the other hand, the sulfide in the steel is denatured; the Ca content of the steel grade is suitably in the range of 0.0005 to 0.0025 percent.
Further, the steel plate is formed by rolling a 227mm continuous casting billet, and the thickness range of the steel plate is 30-58 mm.
The second aspect of the invention provides a production method of a quenched and tempered steel plate with low yield ratio, high strength and low temperature toughness, comprising the following steps: smelting, casting, heating, heat preservation, rolling, air cooling, shot blasting, quenching and tempering.
Further, in the heating procedure, the heating temperature of the plate blank is 1080-1150 ℃, and the average temperature of the plate blank reaches 1100 ℃ and is kept for more than or equal to 30 minutes.
Further, in the rolling procedure, the first stage rolling is a rough rolling stage, and the slab is directly rolled after being discharged from the furnace; the second stage is a finish rolling stage, the temperature of the initial rolling core part is less than or equal to 900 ℃, and the initial rolling core part is air cooled to room temperature after rolling.
Further, the steel plate is subjected to shot blasting and then enters quenching, the quenching heating temperature of the steel plate is 910+/-10 ℃, and the holding time of the core part of the steel plate after the core part of the steel plate reaches the temperature is more than or equal to 10min.
Further, in the tempering process, the tempering temperature of the steel plate is 600-685 ℃, the retention time of the core part of the steel plate after reaching the set temperature is more than or equal to 10min, and the steel plate is cooled after being discharged from the furnace.
The invention has the beneficial effects that:
the invention overcomes the defects of the technology adopted in the current domestic production of the quenched and tempered steel plate with low yield ratio, high strength and low temperature toughness in terms of chemical components, production process and mechanical properties of the steel plate, produces the steel for water and electricity which can meet higher requirements, and meets the requirements of high-quality development; the yield strength of the steel plate is more than or equal to 570MPa, the tensile strength is more than or equal to 640MPa, the elongation is more than or equal to 20%, the yield ratio is less than or equal to 0.92, the Charpy notch impact power Kv2 at-40 ℃ is more than or equal to 200J, and the Charpy notch impact power Kv2 at-40 ℃ is more than or equal to 150J after the steel plate is subjected to 5% strain and aging at 250 ℃ for 1 h.
Drawings
FIG. 1 is a microstructure of a 44mm steel plate according to the present invention.
Detailed Description
The following describes the embodiments of the present disclosure further by way of specific examples, which are intended to describe the disclosure in detail, but not to limit the disclosure. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are intended to be within the scope of the present disclosure.
Examples 1 to 5 and comparative examples 1 to 5
First steel plate sample and preparation
1. Steel plate sample
The quenched and tempered steel plate with low yield ratio, high strength and low temperature toughness provided by the embodiment is prepared by smelting the components with the mass percentages shown in the table 1.
TABLE 1 chemical composition (%)
The structure of the steel plate is shown in fig. 1, and the steel plate prepared in the embodiment is tempered sorbite.
2. Steel plate production process
The production method of the steel sheets of examples 1 to 5 and comparative examples 1 to 5 comprises the steps of: smelting, casting, heating, heat preservation, rolling, air cooling, shot blasting, quenching and tempering, wherein specific process parameters are shown in table 2:
TABLE 2 production Process of examples 1-5 and comparative examples 1-5
(II) Steel plate Performance test
The steel sheets of examples 1 to 5 and comparative examples 1 to 5 were subjected to performance test, and the results are shown in Table 3.
Table 3 example steel sheet properties
As can be seen from Table 3, the thickness of the steel sheets of examples 1-5 ranged from 32 to 58mm; the yield strength of the steel plate is more than or equal to 570MPa, the tensile strength is more than or equal to 640MPa, the elongation is more than or equal to 20%, the yield ratio is less than or equal to 0.92, the Charpy notch impact power Kv2 at-40 ℃ is more than or equal to 200J, the Charpy notch impact power Kv2 at-40 ℃ after the steel plate is subjected to 5% strain and aging at 250 ℃ for 1h is more than or equal to 150J, and the comprehensive performance is obviously better than that of comparative examples 1-5. The method can produce the steel for water and electricity, which can meet higher requirements and meets the requirement of high-quality development.
Although embodiments of the present disclosure have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations may be made therein without departing from the principles and spirit of the disclosure, the scope of which is defined in the appended claims and their equivalents.

Claims (10)

1. The quenched and tempered steel plate with low yield ratio, high strength and low temperature toughness is characterized by being prepared by smelting the following components in percentage by mass: c:0.05 to 0.08 percent, si:0.15 to 0.25 percent, mn:1.43 to 1.53 percent, P is less than or equal to 0.012 percent, S is less than or equal to 0.002 percent, cu: 0.06-0.10%, ni:0.15 to 0.27 percent, cr:0.12 to 0.20 percent, mo:0.10 to 0.20 percent, V:0.02 to 0.04 percent, ti:0.007 to 0.015 percent, B:0.0008 to 0.0014 percent, al:0.04 to 0.06 percent, ca:0.0005 to 0.0025 percent, and the balance of Fe and unavoidable impurities, and satisfies the following conditions: ceq (%) = C+Si/24+Mn/6+Ni/40+Cr/5+Mo/4+V/14 0.39.ltoreq.Ceq (%).
2. The quenched and tempered steel plate with low yield ratio, high strength and low temperature toughness according to claim 1, which is characterized by being prepared by smelting the following components in percentage by mass: c:0.05 to 0.071 percent, si:0.15 to 0.233 percent, mn:1.43 to 1.503 percent, P is less than or equal to 0.012 percent, S is less than or equal to 0.002 percent, cu: 0.06-0.07%, ni:0.15 to 0.243 percent, cr:0.12 to 0.171 percent, mo:0.10 to 0.172 percent, V:0.02 to 0.039 percent, ti:0.007 to 0.013 percent, B:0.0008 to 0.0013 percent, al:0.04 to 0.054 percent, ca:0.0005 to 0.0016 percent, and the balance of Fe and unavoidable impurities, and satisfies the following conditions: ceq (%) = C+Si/24+Mn/6+Ni/40+Cr/5+Mo/4+V/14 0.39.ltoreq.Ceq (%).
3. The quenched and tempered steel plate with low yield ratio, high strength and low temperature toughness according to claim 2, which is characterized by being prepared by smelting the following components in percentage by mass: c:0.059 to 0.071 percent, si: 0.195-0.233%, mn:1.445 to 1.503 percent, P is less than or equal to 0.008 percent, S is less than or equal to 0.0007 percent, cu: 0.06-0.07%, ni:0.221 to 0.243 percent, cr:0.149 to 0.171 percent, mo:0.164 to 0.172 percent, V: 0.031-0.039%, ti: 0.011-0.013%, B:0.0010 to 0.0013 percent, al:0.04 to 0.054 percent, ca:0.0013 to 0.0016 percent, and the balance of Fe and unavoidable impurities, and satisfies the following conditions: ceq (%) is more than or equal to 0.394 and is less than or equal to C+Si/24+Mn/6+Ni/40+Cr/5+Mo/4+V/14 and is less than or equal to 0.412.
4. The quenched and tempered steel plate with low yield ratio, high strength and low temperature toughness according to claim 3, which is characterized by being prepared by smelting the following components in percentage by mass: c:0.059 to 0.066 percent, si: 0.195-0.208%, mn:1.445 to 1.480 percent, P is less than or equal to 0.01 percent, S is less than or equal to 0.0016 percent, cu:0.06 to 0.067 percent, ni:0.221 to 0.232 percent, cr:0.149 to 0.167 percent, mo:0.164 to 0.166 percent, V: 0.031-0.037%, ti: 0.011-0.012%, B:0.0010 to 0.0011 percent, al:0.04 to 0.053 percent, ca:0.0013 to 0.0015 percent, and the balance of Fe and unavoidable impurities, and satisfies the following conditions: ceq (%) is more than or equal to 0.396 and C+Si/24+Mn/6+Ni/40+Cr/5+Mo/4+V/14 is more than or equal to 0.412.
5. The quenched and tempered steel plate with low yield ratio, high strength and low temperature toughness according to claim 4, which is characterized by being prepared by smelting the following components in percentage by mass: c:0.060 to 0.066 percent, si:0.199 to 0.208 percent, mn:1.451 to 1.480 percent, P is less than or equal to 0.009 percent, S is less than or equal to 0.00106 percent, cu: 0.066-0.067%, ni: 0.225-0.232%, cr:0.154 to 0.167 percent, mo: 0.165-0.166%, V:0.034 to 0.037 percent, ti:0.012%, B:0.0011%, al:0.049 to 0.053 percent, ca:0.0014 to 0.0015 percent, and the balance of Fe and unavoidable impurities, and satisfies the following conditions: ceq (%) is more than or equal to 0.396 and C+Si/24+Mn/6+Ni/40+Cr/5+Mo/4+V/14 is more than or equal to 0.400.
6. The method for producing a quenched and tempered high strength, low temperature ductile steel plate according to any one of claims 1 to 4, comprising the steps of: smelting, casting, heating, heat preservation, rolling, air cooling, shot blasting, quenching and tempering.
7. The production method according to claim 6, wherein in the heating step, the heating temperature of the slab is 1080-1150 ℃, and the average temperature of the slab reaches 1100 ℃ and is kept for more than or equal to 30 minutes.
8. The method according to claim 6, wherein in the rolling step, the first stage rolling is a rough rolling stage, and the slab is directly rolled after being discharged from the furnace; the second stage is a finish rolling stage, the temperature of the initial rolling core part is less than or equal to 900 ℃, and the initial rolling core part is air cooled to room temperature after rolling.
9. The production method according to claim 6, wherein the steel plate is quenched after shot blasting, the quenching heating temperature of the steel plate is 910+/-10 ℃, and the holding time of the core part of the steel plate after reaching the temperature is more than or equal to 10min.
10. The method according to claim 6, wherein in the tempering step, the tempering temperature of the steel plate is 600-685 ℃, the holding time of the steel plate core after reaching the set temperature is not less than 10min, and the steel plate is cooled by air after being discharged from the furnace.
CN202310870643.0A 2023-07-17 2023-07-17 Quenched and tempered steel plate with low yield ratio, high strength and low temperature toughness for hydropower and production method thereof Pending CN116855831A (en)

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