CN111270151A - Q345E steel plate and production method thereof - Google Patents

Q345E steel plate and production method thereof Download PDF

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Publication number
CN111270151A
CN111270151A CN202010237899.4A CN202010237899A CN111270151A CN 111270151 A CN111270151 A CN 111270151A CN 202010237899 A CN202010237899 A CN 202010237899A CN 111270151 A CN111270151 A CN 111270151A
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rolling
steel plate
stage
thickness
continuous casting
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温利军
薛越
李�浩
王国海
张满全
赵超
高军
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Baotou Iron and Steel Group Co Ltd
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    • 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
    • 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
    • C21D8/00Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226Hot rolling
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/002Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • 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
    • C22C38/06Ferrous alloys, e.g. steel alloys containing aluminium
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/14Ferrous alloys, e.g. steel alloys containing titanium or zirconium
    • 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
    • C21D2211/005Ferrite
    • 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
    • C21D2211/009Pearlite

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  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Heat Treatment Of Steel (AREA)

Abstract

The invention discloses a Q345E steel plate and a production method thereof, belonging to the field of structural steel. The Q345E steel plate comprises the following chemical components in percentage by mass: c: 0.16-0.18%; si: 0.25 to 0.35 percent; mn: 0.3-0.4%; 0.061-0.065% of Ti; p is less than or equal to 0.014%; s is less than or equal to 0.003 percent; ca: 0.0010-0.0025%; and Als: 0.017-0.033%; the balance of iron and unavoidable impurities. The invention produces the Q345E steel plate with good comprehensive performance through proper smelting, continuous casting, heating, rolling and controlled cooling processes, the yield strength is 396 MPa-445 MPa, the tensile strength is 512-553 MPa, the elongation is 31% -34%, and the impact energy at minus 40 ℃ is 146J-215J.

Description

Q345E steel plate and production method thereof
Technical Field
The invention belongs to the field of structural steel, and particularly relates to a Q345E steel plate and a production method thereof.
Background
The Q345E low-alloy high-strength structural steel plate is widely applied to the fields of engineering machinery, wind power tower poles, bridge construction, equipment structural member manufacturing and the like. The national standard of Q345E steel plate requires that the impact energy at-40 ℃ is not less than 34J, and the steel plate has high strength and good low-temperature toughness. The final structure of the Q345E steel plate is generally ferrite plus pearlite, the component design of the Q345E steel plate is generally that a certain amount of microalloy such as Nb, V, Ti and the like is added on the basis of the C-Mn component design, and ferrite grains are fully refined through controlled rolling, controlled cooling process or heat treatment to ensure that the strength and the toughness of the steel plate meet the requirements.
CN 101871083B discloses an ultra-thick low-alloy high-strength Q345 series steel plate and a production method thereof, and provides a production method of a Q345E thick steel plate. The method has the advantages of meeting the production strength requirement and good toughness. However, the method needs to add micro-alloys such as Nb and Ni, and the cost of the alloy is high.
CN 102041437B discloses a Q345E-Z35 steel plate for a high-rise building with the thickness of 160mm, and provides a production method of the Q345E steel plate. The method has the advantages of meeting the production strength requirement and good toughness. However, the method needs to add more Nb, Ni, V and the like, the alloy cost of the steel plate is higher, and the method is mainly used for producing thick steel plates.
CN 102899556B discloses a production method of a low-alloy medium-thickness steel plate, and provides a production method of a Q345D/E steel plate. The method has the advantages of meeting the production strength requirement and good toughness. However, the method needs to add microalloy Nb, and the alloy cost is higher.
Disclosure of Invention
In view of one or more of the problems in the prior art, an aspect of the present invention provides a Q345E steel sheet, which comprises the following chemical components by mass percent: c: 0.16-0.18%; si: 0.25 to 0.35 percent; mn: 0.3-0.4%; 0.061-0.065% of Ti; p is less than or equal to 0.014%; s is less than or equal to 0.003 percent; ca: 0.0010-0.0025%; and Als: 0.017-0.033%; the balance of iron and unavoidable impurities.
The mechanical properties of the Q345E steel plate meet the following requirements: the yield strength is 396MPa to 445MPa, the tensile strength is 512 MPa to 553MPa, the elongation is 31 percent to 34 percent, and the impact energy at minus 40 ℃ is 146J to 215J.
The thickness of the Q345E steel plate is 14-40 mm.
The invention also provides a production method of the Q345E steel plate, which comprises the processes of smelting, continuous casting, heating, rolling and cooling, wherein:
1) smelting: carrying out RH furnace treatment on the molten steel, wherein the treatment time is not less than 18 minutes under the condition that the vacuum degree is not more than 122 Pa;
2) continuous casting: during continuous casting, electromagnetic stirring and soft reduction are adopted, the electromagnetic stirring frequency is 6.5Hz, the current is 290A, the reduction positions are 6, 7 and 8 sections, the reduction amount is 2.3mm, 2.3mm and 2.3mm, and the thickness of a continuous casting billet is 250 mm;
3) a heating process: a step-type heating furnace is adopted, the discharging temperature of the continuous casting billet is 1220-1240 ℃, the heating time is 200-270 minutes, and the moving speed of the movable beam for supporting the continuous casting billet during heating in the heating furnace is 1.18 m/min;
4) the rolling forming process of the steel plate with the thickness of 14 mm-21 mm comprises the following steps: after the continuous casting billet is heated, controlled rolling is carried out, the initial rolling thickness of the first stage is the thickness of the continuous casting billet, the initial rolling temperature of the first stage is 1210-1230 ℃, the final rolling temperature of the first stage is more than or equal to 970 ℃, the single-pass reduction rate during high-temperature extension rolling of the first stage is more than or equal to 11%, and the rolling speed of the first stage is 1.8-3.0 m/s; the initial rolling thickness of the second-stage steel plate is 4 times of the thickness of the finished steel plate, the initial rolling temperature of the second-stage steel plate is 880-910 ℃, and the final rolling temperature of the second stage is 800-820 ℃; the rolling speed of the second stage is 2.8-4.2 m/s, laminar cooling is carried out after rolling is finished, the cooling speed is 25-30 ℃/s, and the final cooling temperature is 660-690 ℃;
5) the rolling forming process of the steel plate with the thickness of more than 21 mm-40 mm comprises the following steps: after the continuous casting billet is heated, controlled rolling is carried out, the initial rolling thickness of the first stage is the thickness of the continuous casting billet, the initial rolling temperature of the first stage is 1210-1230 ℃, the final rolling temperature of the first stage is more than or equal to 1000 ℃, the single pass reduction rate during high-temperature extension rolling of the first stage is more than or equal to 11.5%, and the rolling speed of the first stage is 1.5-2.5 m/s; the initial rolling thickness of the second-stage steel plate is 3.2-4 times of the thickness of the finished steel plate, the initial rolling temperature of the second-stage steel plate is 870-890 ℃, and the final rolling temperature of the second stage is 800-820 ℃; the rolling speed of the second stage is 2.1-3.2 m/s, laminar cooling is carried out after rolling is finished, the cooling speed is 12-22 ℃/s, and the final cooling temperature is 660-690 ℃.
The Q345E steel plate production method based on the technical scheme adopts low-cost component design, only adopts cheap Si, Mn, Ti and other alloys, and obtains the Q345E steel plate with good comprehensive performance through proper heating, controlled rolling and controlled cooling processes, and data show that the Q345E steel plate has yield strength of 396-445 MPa, tensile strength of 512-553 MPa, elongation of 31-34% and impact work at-40 ℃ of 146-215J. The steel plate has good strength, plasticity and toughness, and the structure is fine ferrite plus pearlite. In conclusion, the invention provides the Q345E steel plate with good surface quality and good matching of strength and toughness and the production method thereof, and the method has the advantages of simple process and low cost, and is suitable for large-scale popularization and use.
Drawings
FIG. 1 is a metallographic structure diagram of a steel sheet according to example 1;
FIG. 2 is a metallographic structure diagram of a steel sheet according to example 2;
FIG. 3 is a metallographic structure diagram of a steel sheet according to example 3;
FIG. 4 is a metallographic structure diagram of a steel sheet according to example 4;
FIG. 5 is a metallographic structure diagram of a steel sheet according to example 5;
FIG. 6 is a metallographic structure chart of a steel sheet according to example 6.
Detailed Description
The invention provides a Q345E steel plate and a production method thereof, wherein the Q345E steel plate comprises the following chemical components in percentage by mass: c: 0.16-0.18%; si: 0.25 to 0.35 percent; mn: 0.3-0.4%; 0.061-0.065% of Ti; p is less than or equal to 0.014%; s is less than or equal to 0.003 percent; ca: 0.0010-0.0025%; and Als: 0.017-0.033%; the balance of iron and unavoidable impurities.
The invention adopts higher heating temperature, so that Ti in the steel can be fully dissolved in the steel during heating, so that carbon and nitride of the Ti can be fully precipitated during cooling after rolling and rolling, and the structure of the steel plate is improved. And (3) performing controlled rolling on the heated continuous casting billet in an austenite recrystallization zone and a non-recrystallization zone. The steel grade adopts two-stage controlled rolling, the first stage controlled rolling belongs to austenite recrystallization controlled rolling in a high temperature region, and the first stage adopts a low-speed and high-reduction rolling strategy. The large single-pass reduction rate can enable rolling deformation to fully penetrate to the center of the steel plate, fully refine austenite grains and homogenize austenite structure, and simultaneously the high-temperature welding effect generated by rolling can eliminate the defects of looseness, microcracks and the like in the casting blank to a great extent, so that the density of the steel plate is improved, and the comprehensive performance of the material is improved; in the first stage of rolling, because the billets are thick and the temperature is reduced slowly, the steel plate is subjected to large temperature reduction after each pass of rolling by adopting low-speed rolling, so that grains can be refined to different degrees after each pass of rolling, and finally, the aim of fully refining austenite grains is fulfilled; and the rolling speed is low during rolling, the deformation resistance is small, and the large single-pass reduction rate is easy to realize. The lower rolling speed can also obtain lower finishing temperature, and fine austenite grains are obtained.
After the first-stage rolling is finished, the intermediate blank swings on the roller way to cool, and starts to roll when the temperature is reduced to the second-stage rolling temperature, wherein the second-stage rolling belongs to low-temperature non-recrystallization controlled rolling. Through the precipitation of Ti carbonitride, the dislocation is pinned, the strain is generated in the crystal grains under the rolling deformation, and through the multi-pass rolling and the larger accumulated reduction, a large amount of deformation energy and phase transformation nucleation positions are accumulated in the crystal grains. And rapidly cooling to a lower temperature after rolling to finish the transformation from austenite to ferrite and pearlite, refining ferrite grains, and precipitating Ti carbonitride in the ferrite in subsequent air cooling to obtain a structure with good obdurability and matching.
The finally obtained steel plate has good strength, plasticity and toughness, and the structure is fine ferrite plus pearlite. The yield strength of the steel plate is 396MPa to 445MPa, the tensile strength is 512 MPa to 553MPa, the elongation is 31 percent to 34 percent, and the impact energy at minus 40 ℃ is 146J to 215J.
The present invention will be described in detail below with reference to specific examples, which are provided only for the purpose of illustrating the present invention for easy understanding and are not intended to limit the present invention.
Example 1
RH treatment is carried out on the molten steel, the time of vacuum degree below 122Pa is 18 minutes, the frequency of electromagnetic stirring is 6.5Hz, the current is 290A, the reduction positions are 6, 7 and 8 sections, the reduction amount is 2.3mm, 2.3mm and 2.3mm, and the thickness of the continuous casting billet is 250 mm. When the continuous casting billet is heated, a stepping heating furnace is adopted, the moving speed of the movable beam for supporting the continuous casting billet when the continuous casting billet is heated in the heating furnace is 1.18m/min, the tapping temperature is 1240 ℃, and the heating time is 270 minutes. The slab comprises the following chemical components in percentage by weight: 0.16% of C, 0.25% of Si, 0.4% of Mn, 0.061% of Ti, 0.014% of P, 0.003% of S, 0.017% of Als, 0.0010% of Ca0, and the balance of Fe and inevitable impurities. The steel plate with the thickness of 14mm is rolled, the detailed rolling and cooling process is shown in table 1, the mechanical property is shown in table 2, and the metallographic structure of the steel plate is shown in fig. 1.
TABLE 1 Rolling and Cooling Process
Figure BDA0002431615390000041
TABLE 2 mechanical Properties of the Steel sheets
Figure BDA0002431615390000042
Example 2
RH treatment is carried out on the molten steel, the time of vacuum degree below 120Pa is 18.5 minutes, the frequency of electromagnetic stirring is 6.5Hz, the current is 290A, the reduction positions are 6, 7 and 8 sections, the reduction amount is 2.3mm, 2.3mm and 2.3mm, and the thickness of the continuous casting billet is 250 mm. When the continuous casting billet is heated, a stepping heating furnace is adopted, the moving speed of the movable beam for supporting the continuous casting billet when the continuous casting billet is heated in the heating furnace is 1.18m/min, the tapping temperature is 1220 ℃, and the heating time is 200 minutes. The slab comprises the following chemical components in percentage by weight: 0.18% of C, 0.35% of Si, 0.3% of Mn, 0.065% of Ti, 0.013% of P, 0.002% of S, 0.033% of Als, 0.0025% of Ca and the balance of Fe and inevitable impurities. The steel plate is rolled into a steel plate with the thickness of 21mm, the detailed rolling and cooling process is shown in Table 3, the mechanical property is shown in Table 4, and the metallographic structure of the steel plate is shown in FIG. 2.
TABLE 3 Rolling and Cooling Process
Figure BDA0002431615390000043
TABLE 4 mechanical Properties of the Steel sheets
Figure BDA0002431615390000044
Example 3
The molten steel is subjected to RH treatment, the time of vacuum degree below 120Pa is 19.5 minutes, the frequency of electromagnetic stirring during slab continuous casting is 6.5Hz, the current is 285A, the reduction positions are 6, 7 and 8 sections, the reduction amount is 2.2mm, 2.2mm and 2.2mm, and the thickness of the continuous casting slab is 250 mm. When the continuous casting billet is heated, a stepping heating furnace is adopted, the moving speed of the movable beam for supporting the continuous casting billet when the continuous casting billet is heated in the heating furnace is 1.18m/min, the tapping temperature is 1231 ℃, and the heating time is 246 minutes. The slab comprises the following chemical components in percentage by weight: 0.17% of C, 0.33% of Si, 0.34% of Mn, 0.062% of Ti, 0.014% of P, 0.002% of S, 0.028% of Als, 0.0021% of Ca and the balance of Fe and inevitable impurities. The steel plate with the thickness of 18mm is rolled, the detailed rolling and cooling process is shown in Table 5, the mechanical properties are shown in Table 6, and the metallographic structure of the steel plate is shown in FIG. 3.
TABLE 5 Rolling and Cooling Process
Figure BDA0002431615390000051
TABLE 6 mechanical Properties of the Steel sheets
Figure BDA0002431615390000052
Example 4
The molten steel is subjected to RH treatment, the time of the vacuum degree below 122Pa is 18.5 minutes, the frequency of electromagnetic stirring during slab continuous casting is 6.5Hz, the current is 290A, the reduction positions are 6, 7 and 8 sections, the reduction amount is 2.3mm, 2.3mm and 2.3mm, and the thickness of the continuous casting slab is 250 mm. When the continuous casting billet is heated, a stepping heating furnace is adopted, the moving speed of the movable beam for supporting the continuous casting billet when the continuous casting billet is heated in the heating furnace is 1.18m/min, the tapping temperature is 1232 ℃, and the heating time is 252 minutes. The slab comprises the following chemical components in percentage by weight: 0.17% of C, 0.28% of Si, 0.36% of Mn, 0.062% of Ti, 0.011% of P, 0.002% of S, 0.029% of Als, 0.0023% of Ca and the balance of Fe and inevitable impurities. The steel plate with the thickness of 40mm is rolled, the detailed rolling and cooling process is shown in Table 7, the mechanical property is shown in Table 8, and the metallographic structure of the steel plate is shown in FIG. 4.
TABLE 7 Rolling and Cooling Process
Figure BDA0002431615390000053
TABLE 8 mechanical Properties of the Steel sheets
Figure BDA0002431615390000061
Example 5
The molten steel is subjected to RH treatment, the time of the vacuum degree below 122Pa is 19.5 minutes, the frequency of electromagnetic stirring during slab continuous casting is 6.5Hz, the current is 290A, the reduction positions are 6, 7 and 8 sections, the reduction amount is 2.3mm, 2.3mm and 2.3mm, and the thickness of the continuous casting slab is 250 mm. When the continuous casting billet is heated, a stepping heating furnace is adopted, the moving speed of the movable beam for supporting the continuous casting billet when the continuous casting billet is heated in the heating furnace is 1.18m/min, the tapping temperature is 1235 ℃, and the heating time is 253 minutes. The slab comprises the following chemical components in percentage by weight: 0.16% of C, 0.33% of Si, 0.36% of Mn, 0.064% of Ti, 0.014% of P, 0.003% of S, 0.017% of Als, 0.0021% of Ca and the balance of Fe and inevitable impurities. The steel plate is rolled into a thickness of 22mm, the detailed rolling and cooling process is shown in Table 9, the mechanical properties are shown in Table 10, and the metallographic structure of the steel plate is shown in FIG. 5.
TABLE 9 Rolling and Cooling Process
Figure BDA0002431615390000062
TABLE 10 mechanical Properties of the Steel sheets
Figure BDA0002431615390000063
Example 6
RH processing is carried out on the molten steel, the time of vacuum degree below 120Pa is 20 minutes, the frequency of electromagnetic stirring is 6.5Hz, the current is 290A, the reduction positions are 6, 7 and 8 sections, the reduction amount is 2.3mm, 2.3mm and 2.3mm, and the thickness of the continuous casting billet is 250 mm. When the continuous casting billet is heated, a stepping heating furnace is adopted, the moving speed of the movable beam for supporting the continuous casting billet when the continuous casting billet is heated in the heating furnace is 1.18m/min, the tapping temperature is 1229 ℃, and the heating time is 238 minutes. The slab comprises the following chemical components in percentage by weight: 0.18% of C, 0.31% of Si, 0.36% of Mn, 0.062% of Ti, 0.013% of P, 0.001% of S, 0.017% of Als, 0.0016% of Ca0, and the balance of Fe and inevitable impurities. The steel plate was rolled to a thickness of 28mm, the detailed rolling and cooling process is shown in Table 11, the mechanical properties are shown in Table 12, and the metallographic structure of the steel plate is shown in FIG. 6.
TABLE 11 Rolling and Cooling Process
Figure BDA0002431615390000071
TABLE 12 mechanical Properties of the Steel sheets
Figure BDA0002431615390000072
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (4)

1. A Q345E steel plate is characterized in that the steel plate comprises the following chemical components in percentage by mass: c: 0.16-0.18%; si: 0.25 to 0.35 percent; mn: 0.3-0.4%; 0.061-0.065% of Ti; p is less than or equal to 0.014%; s is less than or equal to 0.003 percent; ca: 0.0010-0.0025%; and Als: 0.017-0.033%; the balance of iron and unavoidable impurities.
2. The Q345E steel plate of claim 1, wherein the Q345E steel plate has mechanical properties satisfying: the yield strength is 396MPa to 445MPa, the tensile strength is 512 MPa to 553MPa, the elongation is 31 percent to 34 percent, and the impact energy at minus 40 ℃ is 146J to 215J.
3. The Q345E steel plate according to claim 1 or 2, wherein the thickness of the Q345E steel plate is 14-40 mm.
4. The method for producing the Q345E steel plate as claimed in any one of claims 1-3, which comprises smelting, continuous casting, heating, rolling and cooling processes, and is characterized in that:
1) smelting: carrying out RH furnace treatment on the molten steel, wherein the treatment time is not less than 18 minutes under the condition that the vacuum degree is not more than 122 Pa;
2) continuous casting: during continuous casting, electromagnetic stirring and soft reduction are adopted, the electromagnetic stirring frequency is 6.5Hz, the current is 290A, the reduction positions are 6, 7 and 8 sections, the reduction amount is 2.3mm, 2.3mm and 2.3mm, and the thickness of a continuous casting billet is 250 mm;
3) a heating process: a step-type heating furnace is adopted, the discharging temperature of the continuous casting billet is 1220-1240 ℃, the heating time is 200-270 minutes, and the moving speed of the movable beam for supporting the continuous casting billet during heating in the heating furnace is 1.18 m/min;
4) the rolling forming process of the steel plate with the thickness of 14 mm-21 mm comprises the following steps: after the continuous casting billet is heated, controlled rolling is carried out, the initial rolling thickness of the first stage is the thickness of the continuous casting billet, the initial rolling temperature of the first stage is 1210-1230 ℃, the final rolling temperature of the first stage is more than or equal to 970 ℃, the single-pass reduction rate during high-temperature extension rolling of the first stage is more than or equal to 11%, and the rolling speed of the first stage is 1.8-3.0 m/s; the initial rolling thickness of the second-stage steel plate is 4 times of the thickness of the finished steel plate, the initial rolling temperature of the second-stage steel plate is 880-910 ℃, and the final rolling temperature of the second stage is 800-820 ℃; the rolling speed of the second stage is 2.8-4.2 m/s, laminar cooling is carried out after rolling is finished, the cooling speed is 25-30 ℃/s, and the final cooling temperature is 660-690 ℃;
5) the rolling forming process of the steel plate with the thickness of more than 21 mm-40 mm comprises the following steps: after the continuous casting billet is heated, controlled rolling is carried out, the initial rolling thickness of the first stage is the thickness of the continuous casting billet, the initial rolling temperature of the first stage is 1210-1230 ℃, the final rolling temperature of the first stage is more than or equal to 1000 ℃, the single pass reduction rate during high-temperature extension rolling of the first stage is more than or equal to 11.5%, and the rolling speed of the first stage is 1.5-2.5 m/s; the initial rolling thickness of the second-stage steel plate is 3.2-4 times of the thickness of the finished steel plate, the initial rolling temperature of the second-stage steel plate is 870-890 ℃, and the final rolling temperature of the second stage is 800-820 ℃; the rolling speed of the second stage is 2.1-3.2 m/s, laminar cooling is carried out after rolling is finished, the cooling speed is 12-22 ℃/s, and the final cooling temperature is 660-690 ℃.
CN202010237899.4A 2020-03-30 2020-03-30 Q345E steel plate and production method thereof Pending CN111270151A (en)

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Cited By (2)

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Publication number Priority date Publication date Assignee Title
CN112048679A (en) * 2020-08-18 2020-12-08 包头钢铁(集团)有限责任公司 Production method of low-cost 490MPa bridge steel plate with yield strength
CN112176159A (en) * 2020-10-09 2021-01-05 新疆八一钢铁股份有限公司 Production method for normalizing heat treatment of wind power steel

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