WO2023274218A1 - Continuous hot-rolled high-strength pipeline steel coil having extremely high thickness specification and manufacturing method therefor - Google Patents

Continuous hot-rolled high-strength pipeline steel coil having extremely high thickness specification and manufacturing method therefor Download PDF

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WO2023274218A1
WO2023274218A1 PCT/CN2022/101850 CN2022101850W WO2023274218A1 WO 2023274218 A1 WO2023274218 A1 WO 2023274218A1 CN 2022101850 W CN2022101850 W CN 2022101850W WO 2023274218 A1 WO2023274218 A1 WO 2023274218A1
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rolling
temperature
pipeline steel
hot
thickness
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PCT/CN2022/101850
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French (fr)
Chinese (zh)
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岳江波
邹航
李利巍
徐进桥
梅荣利
黄群新
袁金
崔雷
聂顺
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武汉钢铁有限公司
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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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
    • B21B37/74—Temperature control, e.g. by cooling or heating the rolls or the product
    • 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
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C33/00—Making ferrous alloys
    • C22C33/04—Making ferrous alloys by melting
    • 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
    • C22C38/44—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
    • C22C38/48—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
    • C21D2211/002—Bainite
    • 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

Definitions

  • the invention relates to the field of hot-rolled pipeline steel, in particular to a continuous hot-rolled high-strength pipeline steel coil with limit thickness specification and a manufacturing method thereof.
  • Pipeline steel with a thickness above 23mm was mainly produced by rolling wide and thick plates in the past. Specifications of high-strength pipeline steel coils have become possible.
  • the current mainstream steel grades are generally below Q420 and low-strength grade coils.
  • high-strength thick gauge coils there are mainly four problems, rolling capacity, coiling capacity, Coil dimensions and mechanical properties are precisely controlled.
  • Chinese patent discloses an economical X70 pipeline steel plate used in an ultra-low temperature environment with extra thick specifications.
  • the chemical composition of the steel plate is C 0.02 ⁇ 0.08%, Si 0.2 ⁇ 0.4%, Mn 0.9 ⁇ 1.7%, Al 0.02 ⁇ 0.04%, Nb 0.02 ⁇ 0.08%, V ⁇ 0.05%, Cr ⁇ 0.2%, Ni ⁇ 0.2%, Mo ⁇ 0.1%, Cu ⁇ 0.2 %, Ti0.01 ⁇ 0.02%, B ⁇ 0.0005%, P ⁇ 0.006, S ⁇ 0.001%, N ⁇ 0.002%, O ⁇ 0.0012%, H ⁇ 0.0001%, P+S+[N]+[O]+[ H] ⁇ 100ppm, Pcm ⁇ 0.19 and the balance is Fe and unavoidable impurities.
  • the economical X70 pipeline steel plate used in ultra-thick ultra-low temperature environment is characterized by: the thickness of the steel plate is 33-40.5mm, the yield strength is 490-560MPa, the tensile strength is 580-630MPa, the elongation is ⁇ 40%, and the impact is ⁇ 60°C Work ⁇ 300J, ⁇ 30 °C drop hammer shear area ⁇ 75%.
  • Chinese patent discloses a production method of X70 hot-rolled plate for submarine pipelines, the chemical composition of which is: C: 0.035-0.07%, Si: 0.10 ⁇ 0.35%, Mn: 1.40 ⁇ 1.85%, P: ⁇ 0.010%, S: ⁇ 0.0035%, Alt: 0.01 ⁇ 0.06%, Nb: 0.035 ⁇ 0.07%, Ti: 0.008 ⁇ 0.020%, Mo: 0.10 ⁇ 0.30%, Ni: 0.10 ⁇ 0.25%, Cr: 0.10 ⁇ 0.25%, Cu: 0.10 ⁇ 0.25%, and the balance is Fe and unavoidable impurity elements.
  • the appropriate amount of Ni, Cr, and Cu alloy elements are used to match, and through optimized billet design, strict heating system and enhanced controlled rolling and controlled cooling process, the role of alloying elements is fully utilized and the controlled rolling and controlled cooling process is tapped.
  • the patent requires the production of steel plates with a compression ratio of ⁇ 10 and a 400mm thick billet.
  • Chinese patent discloses an acid-resistant submarine pipeline steel and its preparation method, and its chemical composition weight percentage is: C: 0.03 ⁇ 0.045%, Si: 0.15 ⁇ 0.23%, Mn: 1.2-1.35%, Ni: 0.2-0.4%, Cr: 0.2-0.3%, etc.; when preparing, first select the steel plate compression ratio ⁇ 11; Rough rolling, water cooling and stack cooling after rough rolling, the thickness of the prepared steel plate is 34-48mm.
  • the advantages are high strength, low temperature toughness and good crack arrest ability.
  • Chinese patent discloses a production process for high-grade pipeline steel with low compression ratio and thick specifications.
  • the production process includes the following steps: smelting, refining, slab continuous casting, slab heating, rough descaling, rough rolling, intermediate billet cooling, finish rolling, cooling, and thermal straightening; 250mm continuous casting slab is used to produce 25mm-33mm thick high-grade pipeline steel, so that the production line without the production capacity of extra-thick continuous casting slab can also produce thick high-grade pipeline steel, which improves the pipeline quality.
  • Steel production guarantee capacity is possible to guarantee capacity.
  • the thickness of the slab produced is 245-255mm, and the composition of the steel plate produced by this process is: C: 0.03-0.08%, Si: 0.15-0.35%, Mn: 1.50-2.00% , P ⁇ 0.012%, S ⁇ 0.003%, Nb: 0.05 ⁇ 0.09%, Ti: 0.015 ⁇ 0.025%, Mo ⁇ 0.25%, Cu ⁇ 0.35%, Ni ⁇ 0.30%, Cr ⁇ 0.030%, the rest is Fe and not Avoid impurities.
  • Chinese patent discloses a low compression ratio thick specification X70 grade gas pipeline steel, its components and wt% are: C: 0.03-0.075%, Si : 0.15 ⁇ 0.35%, Mn: 1.30 ⁇ 1.90%, P: ⁇ 0.015%, S: ⁇ 0.002%, N: ⁇ 0.006%, Nb: 0.035 ⁇ 0.065%, V: 0.025 ⁇ 0.05%, Ti: 0.015 ⁇ 0.025 %, Cr: 0.1-0.40%, Ni: 0.1-0.2%, Mo: 0.10-0.25%.
  • Production steps heating the slab with a thickness of 225-235 mm; rough rolling; descaling with high-pressure water; finishing rolling; cooling; straightening, and ready for use.
  • the continuous casting slab with a thickness of 230mm can produce X70 grade pipeline steel with a thickness of 30mm and above in the present invention, and the Rt0.5 of the product is 500-580MPa, the Rm is 600-650MPa, and Rt0.5/Rm ⁇ 0.90 , Elongation A50 ⁇ 24%,; ⁇ 20 °C impact energy KV2 ⁇ 250J, ⁇ 15 °C DWTT section shear rate SA ⁇ 95%; HV10 ⁇ 235.
  • Chinese patent discloses a method for producing pipeline steel plates using continuous casting slabs under the condition of small compression ratio.
  • the continuous casting slab is heated to 1150-1250°C and kept for more than 400 minutes; the heated continuous casting slab is rolled in the austenite recrystallization zone and the austenite non-recrystallization zone, and rolled in the austenite recrystallization zone.
  • the starting rolling temperature is 1150-1200 ° C
  • the width ratio is at least 1.6
  • the thickness to be warmed is 2 to 4 times the thickness of the finished product.
  • the starting rolling temperature is 830-900 ° C ;Cool the rolled steel plate, the starting cooling temperature is 700-800°C, the final cooling temperature is 550-600°C, the cooling rate is 5-20°C/s, and a pipeline with a thickness of 40-50mm ⁇ width of 3200-4000mm is obtained steel plate.
  • the present invention C0.05 ⁇ 0.1%.
  • a continuously cast slab with a thickness of 300mm ⁇ a width of 1800-2000mm is heated to 1150-1250°C and kept for more than 400 minutes.
  • the purpose of the present invention is to address the shortcomings of the above-mentioned technologies, to provide a hot-rolled limit-thickness high-strength pipeline steel coil and its manufacturing method, which can significantly improve the strength and toughness and producibility of thick-gauge pipeline steel, and have better strength and toughness matching and low yield ratio.
  • the present invention designs a hot-rolled limit-thickness high-strength pipeline steel coil, the mass percent of its chemical composition is: C: 0.030-0.055%, Si: 0.10-0.30%, Mn: 1.30-1.65 %, P: ⁇ 0.015%; S: ⁇ 0.0015%, Cr: ⁇ 0.20%, Ni ⁇ 0.10%, Mo: 0.08 ⁇ 0.20%, Nb: 0.04 ⁇ 0.07%, Ti: 0.01 ⁇ 0.025%, Al: 0.01 ⁇ 0.045%, the balance is Fe.
  • the metallographic structure is a structure of granular bainite/acicular ferrite and a small amount of small-sized quasi-polygonal ferrite.
  • a method for manufacturing the hot-rolled limit-thickness specification high-strength pipeline steel coil comprising the following steps:
  • the molten steel is treated with Ca and Mg, and the degree of superheat is controlled at 1530-1550°C during casting;
  • the heating temperature is 1160-1200°C
  • the time in the furnace is 130min-260min
  • the high temperature is 1160-1200°C
  • the holding time is 60-100min
  • the ultra-fast cooling is used to quickly water-cool the steel plate to ensure that the final cooling temperature reaches the final cooling design temperature of 350-470 ° C, and control the temperature fluctuation in the width direction of the entire plate to ⁇ 30 ° C, Prevent longitudinal and transverse mechanical property anisotropy.
  • the segregation of the continuous casting slab is improved by using electromagnetic stirring and dynamic light reduction, and the low power rating of the slab is controlled within the C1.0 grade.
  • the Mg in molten steel is controlled at 0.0004-0.0020%
  • the Ca in molten steel is controlled at 0.0018-0.005%.
  • the furnace charging temperature is controlled below 450°C.
  • the casting slab is fixed with a fixed width machine to ensure the dimensional accuracy and edge temperature uniformity of the slab, high-pressure water descaling to ensure the surface quality of the strip, a short-stroke vertical roller mill to improve the width accuracy of the strip, and hydraulic fine-tuning R2 rolling mill improves strip thickness accuracy, ensures operational stability and avoids camber;
  • the finishing mill is controlled by a hydraulic long-stroke roll gap setting system and an AGC system, and the high-precision control of the profile is realized through a roll shifting, roll bending system, thickness, crown and profile measurement closed-loop control system, wherein, through the roll gap
  • the setting system, bending system and AGC system obtain extremely small thickness error and the best precision value, improve the final rolling temperature, width precision and thickness precision through neural network control technology, and the rolling line surface quality detection system ensures that the hydraulic looper device Effectively control the tension between the racks to ensure the quality of the steel surface.
  • micro-alloyed Nb and Ti are precipitated and strengthened, adding 0.08-0.20% Mo element, expanding the ⁇ phase region, and delaying the ⁇ phase transition to precipitate ferrite first It can promote the formation of acicular ferrite, improve the hardenability of thick steel plates, and contribute to the refinement of austenite grains and the formation of fine bainite during rolling.
  • Ca or Mg treatment inclusion modification technology is also used to refine the inclusions in the steel and promote the denaturation of Al 2 O 3 formed in the steel to a smaller particle size , Al 2 O 3 ⁇ CaO or Al 2 O 3 ⁇ MgO with a more uniform distribution, the modification of inclusions can also promote the denaturation of the plastic MnS precipitated in the traditional solidification process to CaO or MgS in Al 2 O 3 ⁇ CaO or Al 2 O 3 ⁇ MgO precipitates on the surface. Compared with hot-rolled strip-like MnS, this inclusion has smaller size and more dispersed distribution, which can significantly improve the center segregation problem existing in the solidification process.
  • LF+RH (VD) vacuum treatment is adopted, the inclusions are denatured after vacuum treatment, and the continuous casting process is fully protected to achieve the content of harmful elements N, H, O, S and inclusions in the steel.
  • the present invention adopts low compression ratio technology, and adopts 200-250mm conventional continuous casting slab thickness in steelmaking and continuous casting production.
  • Production of thick-walled X65 and X70 pipeline steel coils with a thickness of 23mm to 26mm and a yield strength of 485MPa or above, and the use of low compression ratios to produce ultra-thick specification pipeline steel internal grains are less refined after conventional hot rolling, which also affects the follow-up process. Put forward higher technical requirements.
  • the charging temperature of the continuous casting slab is controlled, and the furnace charging temperature is lowered to promote the microstructure in the slab to undergo austenite to ferrite grain transformation, promote the refinement of the original structure, and reduce the mixed crystal structure and large-sized core structure.
  • controlled heating and heat preservation, controlled rolling in the complete recrystallization zone plus non-recrystallization zone, and ultra-fast cooling after rolling are adopted for rapid and uniform cooling.
  • the original austenite grain size is refined by large reduction, and the reduction rate in the finish rolling stage is greater than 55%, and a sufficient number of dislocations, deformation bands and grain flattening are obtained by large reduction in the non-recrystallized area , to promote subsequent rapid cooling, to obtain a granular bainite or acicular ferrite structure.
  • the comprehensive physical and chemical properties of the steel plate are Rt 0.5 (480 ⁇ 600MPa), tensile R m (545 ⁇ 760MPa), impact ⁇ 30°CKV2 ⁇ 200J, ⁇ 20°CDWTT SA ⁇ 85%, hardness HV10 ⁇ 250, with good strength Toughness matching and low yield strength ratio, size deviation thickness deviation ⁇ 0.2mm ⁇ +0.2mm, tower shape ⁇ 50mm, can meet the technical requirements of X65 and X70 grade pipeline steel coils and steel pipes in thickness specifications.
  • the present invention has the following advantages: due to the use of reasonable composition design and optimized rolling TMCP production process, the strength, toughness and producibility of thick gauge pipeline steel can be significantly improved, and the existing hot continuous rolling limit can be solved.
  • Fig. 1 is a metallographic structure diagram at 1/2 of the rolled centripetal part of a 25.4mm X70 grade pipeline steel according to an embodiment of the present invention
  • Fig. 2 is a metallographic structure diagram at 1/2 of the rolled centripetal part of 25.4mm X65 grade pipeline steel in Example 2 of the present invention.
  • a hot-rolled high-strength pipeline steel coil with extreme thickness specifications the mass percentage of its chemical composition is: C: 0.030-0.055%, Si: 0.10-0.30%, Mn: 1.30-1.65%, P: ⁇ 0.015%; S: ⁇ 0.0015%, Cr: ⁇ 0.20%, Ni ⁇ 0.10%, Mo: 0.08-0.20%, Nb: 0.04-0.07%, Ti: 0.01-0.025%, Al: 0.01-0.045%, and the balance is Fe.
  • the metallographic structure is: granular bainite/acicular ferrite and a small amount of small-sized quasi-polygonal ferrite.
  • the method for manufacturing the above-mentioned hot-rolled limit-thickness high-strength pipeline steel coil includes the following steps:
  • the molten steel is treated with Ca and Mg, and the degree of superheat is controlled at 1530-1550°C during casting;
  • the heating temperature is 1160-1200°C
  • the time in the furnace is 130min-260min
  • the high temperature is 1160-1200°C
  • the holding time is 60-100min
  • the ultra-fast cooling is used to quickly water-cool the steel plate to ensure that the final cooling temperature reaches the final cooling design temperature of 350-470 ° C, and control the temperature fluctuation in the width direction of the entire plate to ⁇ 30 ° C, Prevent longitudinal and transverse mechanical property anisotropy.
  • step A electromagnetic stirring and dynamic light reduction are used to improve the segregation of the continuous casting slab, and the low power rating of the casting slab is controlled to be within the C1.0 grade.
  • the Ca in molten steel is controlled at 0.0018-0.005%; in step B), the furnace charging temperature is controlled below 450°C.
  • the slab is fixed by a fixed width machine to ensure the dimensional accuracy and edge temperature uniformity of the slab.
  • High-pressure water descaling ensures the surface quality of the strip.
  • the short-stroke vertical roller mill improves the width accuracy of the strip.
  • the rolling mill improves the thickness accuracy of the strip, ensures the operation stability, and avoids camber;
  • the finishing mill adopts the hydraulic long-stroke roll gap setting system and the AGC system control, through the roll shifting, bending system, thickness, crown and plate shape
  • the measurement closed-loop control system realizes the high-precision control of the plate shape.
  • the minimum thickness error and the best precision value are obtained through the roll gap setting system, the bending system and the AGC system, and the final rolling temperature and width precision are improved through the neuron network control technology.
  • the rolling line surface quality inspection system ensures that the hydraulic looper device can effectively control the tension between the racks and ensure the steel surface quality.
  • the molten steel is treated with Ca and Mg.
  • the Mg in the molten steel is controlled by 0.0004-0.0020%.
  • the Ca in the molten steel is controlled by 0.0018-0.005%.
  • the superheat during casting Controlled at 1530 ⁇ 1550°C;
  • the heating temperature is 1160-1200°C
  • the time in the furnace is 130min-260min
  • the holding time at a high temperature of 1160-1200°C is 60-100min
  • Three-stage hot rolling In the first stage, two passes of large deformation rolling are carried out in the high-temperature austenite zone above 1050°C. The reduction rate of the first pass is 13%, and the reduction rate of the second pass is 23%. In the first stage, the reduction rate was 33% to fully break the austenite grains; in the second stage, in the temperature range of 1000-1050 °C close to the recrystallization stop temperature, two passes of large deformation rolling were adopted, and the third pass The reduction is 20%, the reduction in the fourth pass is 25%, and the cumulative reduction rate of rough rolling is 60%. Rolling in the non-recrystallization area, the cumulative four-pass reduction rate of finish rolling is 58%, and the final rolling temperature is 810-830°C;
  • the ultra-fast cooling is used to quickly water-cool the steel plate.
  • the water ratio selection needs to take into account that the surface hardness of the steel plate does not exceed the standard.
  • the core temperature is higher.
  • ultra-fast cooling it will turn red.
  • subsequent laminar cooling supplement ensure that the final cooling temperature reaches the final cooling design temperature of 350-470 ° C, and control the temperature fluctuation in the width direction of the entire board to ⁇ 30 ° C to prevent longitudinal and transverse mechanical properties from being different. opposite sex.
  • Embodiment 1 ⁇ Example 8 are set according to the mass percentage of chemical composition, and specific composition takes the following table:
  • composition value list (percentage by weight) of table 1 embodiment 1 ⁇ embodiment 8
  • Example 2 0.030 0.24 1.65 0.0090 0.0012 0.20 0.06 0.20 0.053 0.014 0.036 ⁇ 0.0050
  • Example 3 0.039 0.30 1.50 0.0108 0.0010 0.10 0.09 0.11 0.070 0.018 0.28 ⁇ 0.0018
  • Example 4 0.050 0.18 1.45 0.0150 0.0008 0.14 ⁇ 0.11 0.062 0.017 0.34 ⁇ 0.0019
  • Example 5 0.045 0.25 1.60 0.0086 0.0010 ⁇ ⁇ 0.10 0.060 0.016 0.01 ⁇ 0.0016
  • Example 6 0.044 0.19 1.50 0.0085 0.0015 ⁇ ⁇ 0.16 0.067 0.025 0.18 0.0004 0.0004
  • Example 7 0.050 0.20 1.30 0.0103 0.0008 ⁇ ⁇ 0.10 0.040 0.018 0.26 0.0007 0.0002
  • Example 8 0.054 0.10 1.42 0.0096 0.0007 ⁇ 0.5 0.08 0.058 0.016 0.41 0.0020 0.0003
  • the comprehensive performance of the 8 examples can fully meet the technical index requirements of X70 grade pipeline steel, and has good strength and toughness.
  • the H 2 S corrosion test shows that it has good resistance to H 2 S corrosion performance. See Figure 1 for a representative microscopic metallographic structure.
  • the molten steel is treated with Ca and Mg.
  • the Mg in the molten steel is controlled by 0.0004-0.0020%.
  • the Ca in the molten steel is controlled by 0.0018-0.005%.
  • the superheat during casting Controlled at 1530 ⁇ 1550°C;
  • the heating temperature is 1160-1200°C
  • the time in the furnace is 130min-260min
  • the holding time at a high temperature of 1160-1200°C is 60-100min
  • Three-stage hot rolling In the first stage, two passes of large deformation rolling are carried out in the high-temperature austenite zone above 1050°C. The reduction rate of the first pass is 13%, and the reduction rate of the second pass is 23%. In the first stage, the reduction rate was 33% to fully break the austenite grains; in the second stage, in the temperature range of 1000-1050 °C close to the recrystallization stop temperature, two passes of large deformation rolling were adopted, and the third pass The reduction is 20%, the reduction in the fourth pass is 25%, and the cumulative reduction rate of rough rolling is 60%. Rolling in the non-recrystallization area, the cumulative four-pass reduction rate of finish rolling is 58%, and the final rolling temperature is 810-830°C;
  • the ultra-fast cooling is used to quickly water-cool the steel plate.
  • the water ratio selection needs to take into account that the surface hardness of the steel plate does not exceed the standard.
  • the core temperature is higher.
  • ultra-fast cooling it will turn red.
  • subsequent laminar cooling supplement ensure that the final cooling temperature reaches the final cooling design temperature of 400-500 ° C, and control the temperature fluctuation in the width direction of the entire board to ⁇ 30 ° C to prevent longitudinal and transverse mechanical properties from being different. opposite sex.
  • Embodiment 9 to Embodiment 14 are set according to the mass percentage of the chemical composition, and the specific composition values are as follows in Table 4:
  • composition value list (percentage by weight) of table 4 embodiment 9 ⁇ embodiment 4
  • the invention can remarkably improve the strength, toughness and productivity of the thick specification pipeline steel due to the adoption of reasonable composition design and optimized rolling TMCP production process, and solve the problem of existing hot continuous rolling limit.
  • Thick-wall pipeline steel coil production technical issues comprehensive physical and chemical properties of coil Rt 0.5 (480 ⁇ 600MPa), tensile R m (545 ⁇ 760MPa), impact ⁇ 30 °C KV2 ⁇ 200J, ⁇ 20 °C DWTT SA ⁇ 85%, Hardness HV10 ⁇ 250, with good strength-toughness matching and low yield ratio, dimensional deviation thickness deviation ⁇ 0.2mm ⁇ +0.2mm, tower shape ⁇ 50mm, can meet the thickness specification X65 and X70 grade pipeline steel coil and steel pipe service technology Require.

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  • Heat Treatment Of Steel (AREA)

Abstract

The present invention relates to the field of hot rolled pipeline steel, and discloses a continuous hot-rolled high-strength pipeline steel coil having an extremely high thickness specification, the mass percentages of chemical components thereof being: C: 0.030-0.055％, Si: 0.10-0.30％, Mn: 1.30-1.65％, P: ≤0.015％; S: ≤0.0015％, Cr: ≤0.20％, Ni≤0.10％, Mo: 0.08-0.20％, Nb: 0.04-0.07％, Ti: 0.01-0.025％, Al: 0.01-0.045％, and the remainder being Fe. Also disclosed in the present invention is a manufacturing method for continuous hot-rolled high-strength pipeline steel coil having an extremely high thickness specification. The continuous hot-rolled high-strength pipeline steel coil having an extremely high thickness specification and the manufacturing method therefor of the present invention can significantly improve the strength, toughness, and manufacturability of high-thickness pipeline steel, thereby achieving good strength and toughness matching and a low yield ratio.

Description

一种热连轧极限厚度规格高强管线钢板卷及其制造方法A hot-rolled limit thickness specification high-strength pipeline steel plate coil and its manufacturing method 技术领域technical field
本发明涉及热轧管线钢领域，具体涉及一种热连轧极限厚度规格高强管线钢板卷及其制造方法。The invention relates to the field of hot-rolled pipeline steel, in particular to a continuous hot-rolled high-strength pipeline steel coil with limit thickness specification and a manufacturing method thereof.
背景技术Background technique
随着输送量、输送压力的增大，天然气等能源管网的用钢需求朝着大壁厚、高钢级及优异低温韧性方向发展。厚度23mm以上的管线钢以往主要是由宽厚板轧制生产，近年来随着管厂螺旋管线成型能力逐渐提升和钢铁厂热轧产线的升级也改造完成，热连轧产线开发螺旋管用厚规格的高强管线钢板卷已成为可能。With the increase of transmission volume and transmission pressure, the demand for steel for natural gas and other energy pipeline networks is developing in the direction of large wall thickness, high steel grade and excellent low temperature toughness. Pipeline steel with a thickness above 23mm was mainly produced by rolling wide and thick plates in the past. Specifications of high-strength pipeline steel coils have become possible.
厚度≥23mm以上热连轧板卷，目前主流生产的钢级普遍在Q420级以下低强度级别板卷，对于高强度厚规格板卷，主要存在四方面的问题，轧制能力、卷取能力、板卷外形尺寸和力学性能精确控制。For hot-rolled coils with thickness ≥ 23mm, the current mainstream steel grades are generally below Q420 and low-strength grade coils. For high-strength thick gauge coils, there are mainly four problems, rolling capacity, coiling capacity, Coil dimensions and mechanical properties are precisely controlled.
中国专利(公开日：2017年12月22日、公开号：CN107502821 A)公开了一种特厚规格超低温环境下使用的经济型X70管线钢板，该钢板的化学成分按质量百分比计为C 0.02～0.08％，Si 0.2～0.4％，Mn 0.9～1.7％，Al 0.02～0.04％，Nb 0.02～0.08％，V≤0.05％，Cr≤0.2％，Ni≤0.2％，Mo≤0.1％，Cu≤0.2％，Ti0.01～0.02％，B≤0.0005％，P≤0.006，S≤0.001％，N≤0.002％，O≤0.0012％，H≤0.0001％，P+S+[N]+[O]+[H]≤100ppm，Pcm≤0.19余量为Fe及不可避免的杂质。本申请利用大压缩比轧制技术，强化细化晶粒效果，弥补合金元素降低带来的强度和韧性损失，具有更强的经济性。特厚规格超低温环境下使用的经济型X70管线钢板，其特征在于：钢板的厚度 为33～40.5mm，屈服强度490～560MPa，抗拉强度580～630MPa，延伸率≥40％，～60℃冲击功≥300J，～30℃落锤剪切面积≥75％。Chinese patent (publication date: December 22, 2017, publication number: CN107502821 A) discloses an economical X70 pipeline steel plate used in an ultra-low temperature environment with extra thick specifications. The chemical composition of the steel plate is C 0.02～ 0.08%, Si 0.2～0.4%, Mn 0.9～1.7%, Al 0.02～0.04%, Nb 0.02～0.08%, V≤0.05%, Cr≤0.2%, Ni≤0.2%, Mo≤0.1%, Cu≤0.2 %, Ti0.01～0.02%, B≤0.0005%, P≤0.006, S≤0.001%, N≤0.002%, O≤0.0012%, H≤0.0001%, P+S+[N]+[O]+[ H]≤100ppm, Pcm≤0.19 and the balance is Fe and unavoidable impurities. This application utilizes the large compression ratio rolling technology to strengthen the grain refinement effect and make up for the loss of strength and toughness caused by the reduction of alloy elements, which has stronger economic efficiency. The economical X70 pipeline steel plate used in ultra-thick ultra-low temperature environment is characterized by: the thickness of the steel plate is 33-40.5mm, the yield strength is 490-560MPa, the tensile strength is 580-630MPa, the elongation is ≥40%, and the impact is ~60°C Work ≥ 300J, ~ 30 ℃ drop hammer shear area ≥ 75%.
中国专利(公开日：2011年09月14日、公开号：CN102181796A)公开了一种海底管线用X70热轧中厚板的生产方法，其化学成分按重量百分数为：C：0.035～0.07％，Si：0.10～0.35％，Mn：1.40～1.85％，P：≤0.010％，S：≤0.0035％，Alt：0.01～0.06％，Nb：0.035～0.07％，Ti：0.008～0.020％，Mo：0.10～0.30％，Ni：0.10～0.25％，Cr：0.10～0.25％，Cu：0.10～0.25％，余量为Fe和不可避免杂质元素。在钢板制造过程中，采用适量的Ni、Cr、Cu合金元素匹配，通过优化的坯型设计、严格的加热制度和强化的控轧控冷工艺，充分发挥合金元素作用和挖掘控轧控冷工艺的潜力，使钢板全壁厚上获得均匀细小的针状铁素体为主的组织形态，具有较高的横纵向拉伸强度和优良的低温韧性，完全满足深水海底管线用钢的高性能要求。专利要求生产钢板压缩比≥10，选用400mm厚钢坯。Chinese patent (publication date: September 14, 2011, publication number: CN102181796A) discloses a production method of X70 hot-rolled plate for submarine pipelines, the chemical composition of which is: C: 0.035-0.07%, Si: 0.10～0.35%, Mn: 1.40～1.85%, P: ≤0.010%, S: ≤0.0035%, Alt: 0.01～0.06%, Nb: 0.035～0.07%, Ti: 0.008～0.020%, Mo: 0.10 ～0.30%, Ni: 0.10～0.25%, Cr: 0.10～0.25%, Cu: 0.10～0.25%, and the balance is Fe and unavoidable impurity elements. In the steel plate manufacturing process, the appropriate amount of Ni, Cr, and Cu alloy elements are used to match, and through optimized billet design, strict heating system and enhanced controlled rolling and controlled cooling process, the role of alloying elements is fully utilized and the controlled rolling and controlled cooling process is tapped. The potential of the steel plate to obtain a uniform and fine acicular ferrite-based microstructure on the entire wall thickness, with high transverse and longitudinal tensile strength and excellent low-temperature toughness, fully meets the high-performance requirements of steel for deep-water submarine pipelines . The patent requires the production of steel plates with a compression ratio of ≥10 and a 400mm thick billet.
中国专利(公开日：2017年04月09日、公开号：CN106566991A)公开了一种抗酸性海底管线钢及其制备方法，其化学成份重量百分比为：C：0.03～0.045％，Si：0.15～0.23％，Mn：1.2～1.35％，Ni：0.2～0.4％，Cr：0.2～0.3％等；制备时，首先选择钢板压缩比≥11；然后钢坯热温，在炉时间380～460min；之后经粗轧、粗轧后水冷、堆冷，制备钢板的厚度34～48mm。优点在于，强度高、低温韧性和止裂能力好。Chinese patent (publication date: April 09, 2017, publication number: CN106566991A) discloses an acid-resistant submarine pipeline steel and its preparation method, and its chemical composition weight percentage is: C: 0.03～0.045%, Si: 0.15～ 0.23%, Mn: 1.2-1.35%, Ni: 0.2-0.4%, Cr: 0.2-0.3%, etc.; when preparing, first select the steel plate compression ratio ≥ 11; Rough rolling, water cooling and stack cooling after rough rolling, the thickness of the prepared steel plate is 34-48mm. The advantages are high strength, low temperature toughness and good crack arrest ability.
以上三个专利皆是采用压缩比≥11大压缩比技术生产厚规格管线钢。The above three patents all adopt the technology of large compression ratio ≥ 11 to produce thick gauge pipeline steel.
中国专利(公开日：2014年07月23日、公开号：CN103937950A)公开了一种低压缩比厚规格高级别管线钢的生产工艺。生产工艺包括下述的步骤：冶炼、精炼、板坯连铸、板坯加热，粗除鳞、粗轧、中间坯冷却、精轧、冷却、热矫直；本发明通过控制各个步骤 中的具体的参数及调整工艺步骤，采用250mm连铸坯生产出25mm～33mm的厚规格高等级管线钢，使得没有特厚连铸坯生产能力的生产线也可以生产厚规格高等级的管线钢，提高了管线钢的生产保证能力。在板坯连铸过程中，生产的板坯厚度245～255mm，采用该工艺所生产的钢板成分按质量百分比为：C：0.03～0.08％，Si：0.15～0.35％，Mn：1.50～2.00％，P≤0.012％，S≤0.003％，Nb：0.05～0.09％，Ti：0.015～0.025％，Mo≤0.25％，Cu≤0.35％，Ni≤0.30％，Cr≤0.030％，其余为Fe和不可避免的杂质。Chinese patent (publication date: July 23, 2014, publication number: CN103937950A) discloses a production process for high-grade pipeline steel with low compression ratio and thick specifications. The production process includes the following steps: smelting, refining, slab continuous casting, slab heating, rough descaling, rough rolling, intermediate billet cooling, finish rolling, cooling, and thermal straightening; 250mm continuous casting slab is used to produce 25mm-33mm thick high-grade pipeline steel, so that the production line without the production capacity of extra-thick continuous casting slab can also produce thick high-grade pipeline steel, which improves the pipeline quality. Steel production guarantee capacity. In the slab continuous casting process, the thickness of the slab produced is 245-255mm, and the composition of the steel plate produced by this process is: C: 0.03-0.08%, Si: 0.15-0.35%, Mn: 1.50-2.00% , P≤0.012%, S≤0.003%, Nb: 0.05～0.09%, Ti: 0.015～0.025%, Mo≤0.25%, Cu≤0.35%, Ni≤0.30%, Cr≤0.030%, the rest is Fe and not Avoid impurities.
中国专利(公开日：2016年08月24日、公开号：CN105886912A)公开了一种低压缩比厚规格X70级输气管线钢，其组分及wt％为：C：0.03～0.075％、Si:0.15～0.35％、Mn:1.30～1.90％、P：≤0.015％、S：≤0.002％、N：≤0.006％、Nb：0.035～0.065％、V：0.025～0.05％、Ti:0.015～0.025％、Cr：0.1～0.40％、Ni：0.1～0.2％、Mo：0.10～0.25％。生产步骤：对厚度为225～235mm的铸坯加热；粗轧；高压水除鳞；精轧；冷却；矫直，待用。本发明用连铸坯厚度为230mm的连铸坯能生产厚度为30mm及以上的X70级管线钢，且产品的Rt0.5在500～580MPa，Rm在600～650MPa，Rt0.5/Rm≤0.90，延伸率A50≥24％，；～20℃冲击功KV2≥250J，～15℃DWTT断面剪切率SA≥95％；HV10≤235。Chinese patent (publication date: August 24, 2016, publication number: CN105886912A) discloses a low compression ratio thick specification X70 grade gas pipeline steel, its components and wt% are: C: 0.03-0.075%, Si : 0.15～0.35%, Mn: 1.30～1.90%, P: ≤0.015%, S: ≤0.002%, N: ≤0.006%, Nb: 0.035～0.065%, V: 0.025～0.05%, Ti: 0.015～0.025 %, Cr: 0.1-0.40%, Ni: 0.1-0.2%, Mo: 0.10-0.25%. Production steps: heating the slab with a thickness of 225-235 mm; rough rolling; descaling with high-pressure water; finishing rolling; cooling; straightening, and ready for use. The continuous casting slab with a thickness of 230mm can produce X70 grade pipeline steel with a thickness of 30mm and above in the present invention, and the Rt0.5 of the product is 500-580MPa, the Rm is 600-650MPa, and Rt0.5/Rm≤0.90 , Elongation A50 ≥ 24%,; ~ 20 ℃ impact energy KV2 ≥ 250J, ~ 15 ℃ DWTT section shear rate SA ≥ 95%; HV10 ≤ 235.
中国专利(公开日：2014年03月19日、公开号：CN103639198A)公开了一种小压缩比条件下使用连铸坯生产管线钢板的方法，该方法包括：将厚度300mm×宽度1800～2000mm的连铸坯加热到1150～1250℃并保持400分钟以上；对加热后的连铸坯进行奥氏体再结晶区轧制和奥氏体未再结晶区轧制，在奥氏体再结晶区轧制中，开轧温度为1150～1200℃，展宽比至少为1.6，待温厚度为成品厚度的2～4倍，在奥氏体未再结晶区轧制中，开轧温度为830～900℃；对轧制后的钢板进行冷却，开冷温度为700～800℃，终冷温度为 550～600℃，冷却速度为5～20℃/s，得到厚度40～50mm×宽度3200～4000mm的管线钢板。本发明C0.05～0.1％。将厚度300mm×宽度1800～2000mm的连铸坯加热到1150～1250℃并保持400分钟以上。Chinese patent (publication date: March 19, 2014, publication number: CN103639198A) discloses a method for producing pipeline steel plates using continuous casting slabs under the condition of small compression ratio. The continuous casting slab is heated to 1150-1250°C and kept for more than 400 minutes; the heated continuous casting slab is rolled in the austenite recrystallization zone and the austenite non-recrystallization zone, and rolled in the austenite recrystallization zone. In the rolling process, the starting rolling temperature is 1150-1200 ° C, the width ratio is at least 1.6, and the thickness to be warmed is 2 to 4 times the thickness of the finished product. In rolling in the austenite non-recrystallized region, the starting rolling temperature is 830-900 ° C ;Cool the rolled steel plate, the starting cooling temperature is 700-800°C, the final cooling temperature is 550-600°C, the cooling rate is 5-20°C/s, and a pipeline with a thickness of 40-50mm×width of 3200-4000mm is obtained steel plate. The present invention C0.05～0.1%. A continuously cast slab with a thickness of 300mm×a width of 1800-2000mm is heated to 1150-1250°C and kept for more than 400 minutes.
以上专利都是采用宽厚板产线生产的厚规格钢板，与本专利申请的热连轧产线生产的钢卷生产工艺有本质差别。在热连轧产线生产的特厚23mm以上高强管线钢钢卷专利较少。The above-mentioned patents all use thick-gauge steel plates produced by wide-and-thick plate production lines, which are essentially different from the steel coil production process produced by the hot rolling production line of this patent application. There are few patents for high-strength pipeline steel coils with an extra thickness of 23mm or more produced in the hot rolling production line.
发明内容Contents of the invention
本发明的目的就是针对上述技术的不足，提供一种热连轧极限厚度规格高强管线钢板卷及其制造方法，可以显著提高厚规格管线钢的强韧性和可生产性，具有较好的强韧性匹配和低屈强比。The purpose of the present invention is to address the shortcomings of the above-mentioned technologies, to provide a hot-rolled limit-thickness high-strength pipeline steel coil and its manufacturing method, which can significantly improve the strength and toughness and producibility of thick-gauge pipeline steel, and have better strength and toughness matching and low yield ratio.
为实现上述目的，本发明所设计的一种热连轧极限厚度规格高强管线钢板卷，其化学成分的质量百分比为：C:0.030～0.055％，Si：0.10～0.30％，Mn：1.30～1.65％，P：≤0.015％；S：≤0.0015％，Cr：≤0.20％，Ni≤0.10％，Mo：0.08～0.20％，Nb：0.04～0.07％，Ti：0.01～0.025％，Al：0.01～0.045％，余量为Fe。In order to achieve the above purpose, the present invention designs a hot-rolled limit-thickness high-strength pipeline steel coil, the mass percent of its chemical composition is: C: 0.030-0.055%, Si: 0.10-0.30%, Mn: 1.30-1.65 %, P: ≤0.015%; S: ≤0.0015%, Cr: ≤0.20%, Ni≤0.10%, Mo: 0.08～0.20%, Nb: 0.04～0.07%, Ti: 0.01～0.025%, Al: 0.01～ 0.045%, the balance is Fe.
优选的，金相组织为粒状贝氏体/针状铁素体和少量小尺寸准多边形铁素体的组织结构。Preferably, the metallographic structure is a structure of granular bainite/acicular ferrite and a small amount of small-sized quasi-polygonal ferrite.
一种所述热连轧极限厚度规格高强管线钢板卷的制造方法，包括如下步骤：A method for manufacturing the hot-rolled limit-thickness specification high-strength pipeline steel coil, comprising the following steps:
A)钢水成分合格后，对钢液进行Ca和Mg处理，浇铸时过热度控制在1530～1550℃；A) After the composition of the molten steel is qualified, the molten steel is treated with Ca and Mg, and the degree of superheat is controlled at 1530-1550°C during casting;
B)浇铸成坯后，热装或缓冷后装加热炉加热保温，加热温度为1160～1200℃，在炉时间130min～260min，高温1160～1200℃，保温时间60～100min；B) After casting into a billet, install it in a heating furnace for heating and heat preservation after hot charging or slow cooling. The heating temperature is 1160-1200°C, the time in the furnace is 130min-260min, the high temperature is 1160-1200°C, and the holding time is 60-100min;
C)热轧三阶段轧制：第一阶段，在1050℃以上高温奥氏体区进行1～3道次大变形轧制，单道次压下率≥10％，第一阶段压下率≥30％， 使奥氏体晶粒充分破碎；第二阶段，在接近再结晶停止温度的1000～1050℃温度区间内，采用2～7道次大变形轧制，单道次压下率≥15％，第二阶段压下率≥30％，使原奥氏体晶粒在较低温度下发生动/静态再结晶，同时抑制再结晶后待温过程中的晶粒长大；第三阶段为精轧阶段，精轧开轧温度≤950℃，进行奥氏体未再结晶区轧制，精轧累计四道次压下率不小于58％，终轧温度810～830℃，使奥氏体晶粒充分压扁，在晶粒内部形成大量变形带、孪晶等晶格缺陷，增加其有效晶粒面积，以在轧后的连续冷却相变过程中提高新相的相变质点，细化成品组织；C) Three-stage rolling of hot rolling: in the first stage, 1 to 3 passes of large deformation rolling are carried out in the high-temperature austenite zone above 1050°C, the reduction rate of a single pass is ≥10%, and the reduction rate of the first stage is ≥ 30%, so that the austenite grains are fully broken; in the second stage, in the temperature range of 1000-1050 ℃ close to the recrystallization stop temperature, 2-7 passes of large deformation rolling are adopted, and the reduction ratio of a single pass is ≥15 %, the reduction rate in the second stage is ≥ 30%, so that the dynamic/static recrystallization of the original austenite grains occurs at a lower temperature, and at the same time inhibits the grain growth during the warming process after recrystallization; the third stage is In the finishing rolling stage, the starting temperature of finishing rolling is ≤950°C, rolling in the non-recrystallized area of austenite is carried out, the cumulative reduction ratio of the four passes of finishing rolling is not less than 58%, and the finishing rolling temperature is 810-830°C, so that the austenite The grains are fully flattened, and a large number of deformation bands, twins and other lattice defects are formed inside the grains to increase the effective grain area, so as to increase the phase transition mass point of the new phase during the continuous cooling phase transition process after rolling, and refine Finished tissue;
D)精轧结束后，通过超快冷+层流冷却，超快冷对钢板快速水冷，确保终冷温度达到终冷设计温度350～470℃，并控制全板宽方向温度波动≤30℃，防止纵横向力学性能各向异性。D) After finishing rolling, through ultra-fast cooling + laminar cooling, the ultra-fast cooling is used to quickly water-cool the steel plate to ensure that the final cooling temperature reaches the final cooling design temperature of 350-470 ° C, and control the temperature fluctuation in the width direction of the entire plate to ≤ 30 ° C, Prevent longitudinal and transverse mechanical property anisotropy.
优选的，所述步骤A)中，采用电磁搅拌和动态轻压下改善连铸坯偏析，控制铸坯低倍评级在C1.0级以内。Preferably, in the step A), the segregation of the continuous casting slab is improved by using electromagnetic stirring and dynamic light reduction, and the low power rating of the slab is controlled within the C1.0 grade.
优选的，所述步骤A)中，Mg处理工艺中，钢水中Mg按0.0004～0.0020％控制，Ca处理工艺中，钢水中Ca按0.0018～0.005％控制。Preferably, in the step A), in the Mg treatment process, the Mg in molten steel is controlled at 0.0004-0.0020%, and in the Ca treatment process, the Ca in molten steel is controlled at 0.0018-0.005%.
优选的，所述步骤B)中，装炉温度控制在450℃以下。Preferably, in the step B), the furnace charging temperature is controlled below 450°C.
优选的，粗轧前对铸坯采用定宽机定宽确保铸坯尺寸精度和边部温度均匀性，高压水除鳞确保带钢表面质量，短行程立辊轧机提高带钢宽度精度，液压微调R2轧机，提高带坯厚度精度，确保了操作稳定性，避免产生镰刀弯；Preferably, before the rough rolling, the casting slab is fixed with a fixed width machine to ensure the dimensional accuracy and edge temperature uniformity of the slab, high-pressure water descaling to ensure the surface quality of the strip, a short-stroke vertical roller mill to improve the width accuracy of the strip, and hydraulic fine-tuning R2 rolling mill improves strip thickness accuracy, ensures operational stability and avoids camber;
优选的，精轧机采用液压长行程辊缝设定系统及AGC系统控制，通过窜辊、弯辊系统、厚度、凸度及板型测量闭环控制系统实现板型高精度控制，其中，通过辊缝设定系统、窜弯系统和AGC系统获得极小厚度误差和最好精度值，通过神经元网络控制技术提高终轧温度、宽度精度和厚度精度，轧制线表面质量检测系统确保液压活套装置有效控制机架间张力，确保钢表面质量。Preferably, the finishing mill is controlled by a hydraulic long-stroke roll gap setting system and an AGC system, and the high-precision control of the profile is realized through a roll shifting, roll bending system, thickness, crown and profile measurement closed-loop control system, wherein, through the roll gap The setting system, bending system and AGC system obtain extremely small thickness error and the best precision value, improve the final rolling temperature, width precision and thickness precision through neural network control technology, and the rolling line surface quality detection system ensures that the hydraulic looper device Effectively control the tension between the racks to ensure the quality of the steel surface.
本发明的化学成分设计中：以低碳中锰成分体系为基础，微合 金Nb、Ti析出强化，添加0.08～0.20％Mo元素，扩大γ相区，推迟γ→α相变时先析出铁素体形成，促进针状铁素体形成，且能够提高厚钢板的淬透性，有助于轧制时奥氏体晶粒细化和和微细贝氏体的生成。工艺上冶炼环节对易偏析元素Mn、S、C严格控制外，还采用Ca或Mg处理夹杂物改性技术，细化钢中夹杂，促使钢中形成的Al 2O 3变性成粒径更小、分布更均匀的Al 2O 3～CaO或Al 2O 3～MgO，夹杂物改性处理同时可以促使传统凝固过程中析出的塑性MnS变性为CaO或MgS在Al 2O 3～CaO或Al 2O 3～MgO表面析出，这种夹杂物较热轧态带状MnS具有尺寸小、分散分布特点，可以显著改善凝固过程中存在的中心偏析问题。 In the chemical composition design of the present invention: based on the low-carbon medium manganese composition system, micro-alloyed Nb and Ti are precipitated and strengthened, adding 0.08-0.20% Mo element, expanding the γ phase region, and delaying the γ→α phase transition to precipitate ferrite first It can promote the formation of acicular ferrite, improve the hardenability of thick steel plates, and contribute to the refinement of austenite grains and the formation of fine bainite during rolling. In addition to strict control of segregation-prone elements Mn, S, and C in the smelting process, Ca or Mg treatment inclusion modification technology is also used to refine the inclusions in the steel and promote the denaturation of Al 2 O 3 formed in the steel to a smaller particle size , Al 2 O 3 ～CaO or Al 2 O 3 ～MgO with a more uniform distribution, the modification of inclusions can also promote the denaturation of the plastic MnS precipitated in the traditional solidification process to CaO or MgS in Al 2 O 3 ～CaO or Al 2 O 3 ～MgO precipitates on the surface. Compared with hot-rolled strip-like MnS, this inclusion has smaller size and more dispersed distribution, which can significantly improve the center segregation problem existing in the solidification process.
具体在炼钢过程工艺质量控制上，采用LF+RH(VD)真空处理，真空后夹杂物变性处理，连铸过程全保护浇铸，实现钢中危害元素N、H、O、S和夹杂物含量控制到较低水平，同时在连铸浇铸环节通过控制低过热度浇注和连铸凝固过程电磁搅拌和轻压下减少铸坯的成分和组织宏观偏析。Specifically, in the quality control of the steelmaking process, LF+RH (VD) vacuum treatment is adopted, the inclusions are denatured after vacuum treatment, and the continuous casting process is fully protected to achieve the content of harmful elements N, H, O, S and inclusions in the steel. Control to a lower level, and at the same time reduce the macro-segregation of the composition and structure of the slab by controlling the low superheat pouring and continuous casting solidification process electromagnetic stirring and light pressure in the continuous casting process.
在炼钢铸坯选择上，区别于以往采用厚规格连铸坯大压下生产厚规格管线，本发明采用低压缩比工艺，在炼钢连铸生产中采用200～250mm常规连铸坯厚度，生产厚度23mm～26mm屈服强度485MPa级以上厚壁X65和X70级管线钢板卷，采用低压缩比生产特厚规格管线钢内部晶粒在常规热轧后细化程度较小，这也给对后续工艺提出了更高的技术要求。In the selection of steelmaking slabs, it is different from the thick gauge continuous casting slabs used in the past to produce thick gauge pipelines under high pressure. The present invention adopts low compression ratio technology, and adopts 200-250mm conventional continuous casting slab thickness in steelmaking and continuous casting production. Production of thick-walled X65 and X70 pipeline steel coils with a thickness of 23mm to 26mm and a yield strength of 485MPa or above, and the use of low compression ratios to produce ultra-thick specification pipeline steel internal grains are less refined after conventional hot rolling, which also affects the follow-up process. Put forward higher technical requirements.
首先对连铸坯装炉温度进行控制，降低装炉温度促进铸坯内组织经历奥氏体到铁素体晶粒转变促进原始组织细化，减少混晶组织和大尺寸心部组织。在轧制工艺上采用控制加热保温、完全再结晶区加未再结晶区控制轧制、轧后超快冷快速均匀冷却工艺。在粗轧阶段通过大压下细化原始奥氏体晶粒尺寸，精轧阶段压下率大于55％，通过未再结晶区大压下获得足够数量的位错、变形带和晶粒扁平化，促进后续快速冷却时，获得一种以粒状贝氏体或针状铁素体的组织结构。钢板综合理化性能的Rt 0.5(480～600MPa)，抗拉 R m(545～760MPa)，冲击～30℃KV2≥200J，～20℃DWTT SA≥85％，硬度HV10≤250，具有较好的强韧性匹配和低屈强比，尺寸偏差厚度偏差～0.2mm～+0.2mm，塔形≤50mm，能够满足厚度规格X65和X70级管线钢板卷和钢管服役技术要求。 Firstly, the charging temperature of the continuous casting slab is controlled, and the furnace charging temperature is lowered to promote the microstructure in the slab to undergo austenite to ferrite grain transformation, promote the refinement of the original structure, and reduce the mixed crystal structure and large-sized core structure. In the rolling process, controlled heating and heat preservation, controlled rolling in the complete recrystallization zone plus non-recrystallization zone, and ultra-fast cooling after rolling are adopted for rapid and uniform cooling. In the rough rolling stage, the original austenite grain size is refined by large reduction, and the reduction rate in the finish rolling stage is greater than 55%, and a sufficient number of dislocations, deformation bands and grain flattening are obtained by large reduction in the non-recrystallized area , to promote subsequent rapid cooling, to obtain a granular bainite or acicular ferrite structure. The comprehensive physical and chemical properties of the steel plate are Rt 0.5 (480~600MPa), tensile R m (545~760MPa), impact ~30℃KV2≥200J, ~20℃DWTT SA≥85%, hardness HV10≤250, with good strength Toughness matching and low yield strength ratio, size deviation thickness deviation ~ 0.2mm ~ +0.2mm, tower shape ≤ 50mm, can meet the technical requirements of X65 and X70 grade pipeline steel coils and steel pipes in thickness specifications.
本发明与现有技术相比，具有以下优点：由于采用合理的成分设计和优化的轧制TMCP生产工艺，可以显著提高厚规格管线钢的强韧性和可生产性，解决现有热连轧极限厚壁管线钢板卷生产技术问题，板卷综合理化性能的Rt 0.5(480～600MPa)，抗拉R m(545～760MPa)，冲击～30℃KV2≥200J，～20℃DWTT SA≥85％，硬度HV10≤250，具有较好的强韧性匹配和低屈强比，尺寸偏差厚度偏差～0.2mm～+0.2mm，塔形≤50mm，能够满足厚度规格X65和X70级管线钢板卷和钢管服役技术要求。 Compared with the prior art, the present invention has the following advantages: due to the use of reasonable composition design and optimized rolling TMCP production process, the strength, toughness and producibility of thick gauge pipeline steel can be significantly improved, and the existing hot continuous rolling limit can be solved. Thick-wall pipeline steel coil production technical issues, comprehensive physical and chemical properties of coil Rt 0.5 (480 ~ 600MPa), tensile R m (545 ~ 760MPa), impact ~ 30 ℃ KV2 ≥ 200J, ~ 20 ℃ DWTT SA ≥ 85%, Hardness HV10≤250, with good strength-toughness matching and low yield ratio, dimensional deviation thickness deviation ~0.2mm～+0.2mm, tower shape≤50mm, can meet the thickness specification X65 and X70 grade pipeline steel coil and steel pipe service technology Require.
附图说明Description of drawings
图1为本发明实施例一25.4mm X70级管线钢的轧向心部1/2处金相组织图；Fig. 1 is a metallographic structure diagram at 1/2 of the rolled centripetal part of a 25.4mm X70 grade pipeline steel according to an embodiment of the present invention;
图2为本发明实施例二25.4mm X65级管线钢的轧向心部1/2处金相组织图。Fig. 2 is a metallographic structure diagram at 1/2 of the rolled centripetal part of 25.4mm X65 grade pipeline steel in Example 2 of the present invention.
具体实施方式detailed description
下面结合具体实施例对本发明作进一步的详细说明。The present invention will be further described in detail below in conjunction with specific embodiments.
一种热连轧极限厚度规格高强管线钢板卷，其化学成分的质量百分比为：C:0.030～0.055％，Si：0.10～0.30％，Mn：1.30～1.65％，P：≤0.015％；S：≤0.0015％，Cr：≤0.20％，Ni≤0.10％，Mo：0.08～0.20％，Nb：0.04～0.07％，Ti：0.01～0.025％，Al：0.01～0.045％，余量为Fe。金相组织为：粒状贝氏体/针状铁素体和少量小尺寸准多边形铁素体的组织结构。A hot-rolled high-strength pipeline steel coil with extreme thickness specifications, the mass percentage of its chemical composition is: C: 0.030-0.055%, Si: 0.10-0.30%, Mn: 1.30-1.65%, P: ≤0.015%; S: ≤0.0015%, Cr: ≤0.20%, Ni≤0.10%, Mo: 0.08-0.20%, Nb: 0.04-0.07%, Ti: 0.01-0.025%, Al: 0.01-0.045%, and the balance is Fe. The metallographic structure is: granular bainite/acicular ferrite and a small amount of small-sized quasi-polygonal ferrite.
上述热连轧极限厚度规格高强管线钢板卷的制造方法，包括如下步骤：The method for manufacturing the above-mentioned hot-rolled limit-thickness high-strength pipeline steel coil includes the following steps:
A)钢水成分合格后，对钢液进行Ca和Mg处理，浇铸时过热度控制在1530～1550℃；A) After the composition of the molten steel is qualified, the molten steel is treated with Ca and Mg, and the degree of superheat is controlled at 1530-1550°C during casting;
B)浇铸成坯后，热装或缓冷后装加热炉加热保温，加热温度为1160～1200℃，在炉时间130min～260min，高温1160～1200℃，保温时间60～100min；B) After casting into a billet, install it in a heating furnace for heating and heat preservation after hot charging or slow cooling. The heating temperature is 1160-1200°C, the time in the furnace is 130min-260min, the high temperature is 1160-1200°C, and the holding time is 60-100min;
C)热轧三阶段轧制：第一阶段，在1050℃以上高温奥氏体区进行1～3道次大变形轧制，单道次压下率≥10％，第一阶段压下率≥30％，使奥氏体晶粒充分破碎；第二阶段，在接近再结晶停止温度的1000～1050℃温度区间内，采用2～7道次大变形轧制，单道次压下率≥15％，第二阶段压下率≥30％，使原奥氏体晶粒在较低温度下发生动/静态再结晶，同时抑制再结晶后待温过程中的晶粒长大；第三阶段为精轧阶段，精轧开轧温度≤950℃，进行奥氏体未再结晶区轧制，精轧累计四道次压下率不小于58％，终轧温度810～830℃；C) Three-stage rolling of hot rolling: in the first stage, 1 to 3 passes of large deformation rolling are carried out in the high-temperature austenite zone above 1050°C, the reduction rate of a single pass is ≥10%, and the reduction rate of the first stage is ≥ 30%, so that the austenite grains are fully broken; in the second stage, in the temperature range of 1000-1050 ℃ close to the recrystallization stop temperature, 2-7 passes of large deformation rolling are adopted, and the reduction ratio of a single pass is ≥15 %, the reduction rate in the second stage is ≥ 30%, so that the dynamic/static recrystallization of the original austenite grains occurs at a lower temperature, and at the same time inhibits the grain growth during the warming process after recrystallization; the third stage is In the finishing rolling stage, the starting temperature of finishing rolling is ≤950°C, rolling is carried out in the non-recrystallized zone of austenite, the cumulative reduction ratio of the four passes of finishing rolling is not less than 58%, and the finishing rolling temperature is 810-830°C;
D)精轧结束后，通过超快冷+层流冷却，超快冷对钢板快速水冷，确保终冷温度达到终冷设计温度350～470℃，并控制全板宽方向温度波动≤30℃，防止纵横向力学性能各向异性。D) After finishing rolling, through ultra-fast cooling + laminar cooling, the ultra-fast cooling is used to quickly water-cool the steel plate to ensure that the final cooling temperature reaches the final cooling design temperature of 350-470 ° C, and control the temperature fluctuation in the width direction of the entire plate to ≤ 30 ° C, Prevent longitudinal and transverse mechanical property anisotropy.
其中，步骤A)中，采用电磁搅拌和动态轻压下改善连铸坯偏析，控制铸坯低倍评级在C1.0级以内，Mg处理工艺中，钢水中Mg按0.0004～0.0020％控制，Ca处理工艺中，钢水中Ca按0.0018～0.005％控制；步骤B)中，装炉温度控制在450℃以下。Among them, in step A), electromagnetic stirring and dynamic light reduction are used to improve the segregation of the continuous casting slab, and the low power rating of the casting slab is controlled to be within the C1.0 grade. In the treatment process, the Ca in molten steel is controlled at 0.0018-0.005%; in step B), the furnace charging temperature is controlled below 450°C.
另外，粗轧前对铸坯采用定宽机定宽确保铸坯尺寸精度和边部温度均匀性，高压水除鳞确保带钢表面质量，短行程立辊轧机提高带钢宽度精度，液压微调R2轧机，提高带坯厚度精度，确保了操作稳定性，避免产生镰刀弯；精轧机采用液压长行程辊缝设定系统及AGC系统控制，通过窜辊、弯辊系统、厚度、凸度及板型测量闭环控制系统实现板型高精度控制，其中，通过辊缝设定系统、窜弯系统和AGC系统获得极小厚度误差和最好精度值，通过神经元网络控制技术提高终轧温度、宽度精度和厚度精度，轧制线表面质量检测系统确保液压活套装置有效控制机架间张力，确保钢表面质量。In addition, before rough rolling, the slab is fixed by a fixed width machine to ensure the dimensional accuracy and edge temperature uniformity of the slab. High-pressure water descaling ensures the surface quality of the strip. The short-stroke vertical roller mill improves the width accuracy of the strip. The rolling mill improves the thickness accuracy of the strip, ensures the operation stability, and avoids camber; the finishing mill adopts the hydraulic long-stroke roll gap setting system and the AGC system control, through the roll shifting, bending system, thickness, crown and plate shape The measurement closed-loop control system realizes the high-precision control of the plate shape. Among them, the minimum thickness error and the best precision value are obtained through the roll gap setting system, the bending system and the AGC system, and the final rolling temperature and width precision are improved through the neuron network control technology. And thickness accuracy, the rolling line surface quality inspection system ensures that the hydraulic looper device can effectively control the tension between the racks and ensure the steel surface quality.
实施例一Embodiment one
以采用炼钢230mm铸坯轧制25.4mm X70级管线为例，具体实施步骤为：Taking the rolling of 25.4mm X70 grade pipeline by steelmaking 230mm billet as an example, the specific implementation steps are as follows:
A)钢水成分合格后，对钢液进行Ca和Mg处理，Mg处理工艺中，钢水中Mg按0.0004～0.0020％控制，Ca处理工艺中，钢水中Ca按0.0018～0.005％控制，浇铸时过热度控制在1530～1550℃；A) After the composition of the molten steel is qualified, the molten steel is treated with Ca and Mg. In the Mg treatment process, the Mg in the molten steel is controlled by 0.0004-0.0020%. In the Ca treatment process, the Ca in the molten steel is controlled by 0.0018-0.005%. The superheat during casting Controlled at 1530～1550℃;
B)浇铸成230mm铸坯后，热装或缓冷后装加热炉，加热温度为1160～1200℃，在炉时间130min～260min，高温1160～1200℃保温时间60～100min；B) After casting into a 230mm slab, install it into a heating furnace after hot charging or slow cooling. The heating temperature is 1160-1200°C, the time in the furnace is 130min-260min, and the holding time at a high temperature of 1160-1200°C is 60-100min;
C)热轧三阶段轧制：第一阶段，在1050℃以上高温奥氏体区进行2道次大变形轧制，第一道次压下率13％，第二道次压下率23％，第一阶段压下率33％使奥氏体晶粒充分破碎；第二阶段，在接近再结晶停止温度的1000～1050℃温度区间内，采用2道次大变形轧制，第三道次压下20％，第四道次压下25％，粗轧累计压下率60％；第三阶段为精轧阶段，控扎控冷设定精轧开轧温度≤950℃，进行奥氏体未再结晶区轧制，精轧累计四道次压下率58％，终轧温度810-830℃；C) Three-stage hot rolling: In the first stage, two passes of large deformation rolling are carried out in the high-temperature austenite zone above 1050°C. The reduction rate of the first pass is 13%, and the reduction rate of the second pass is 23%. In the first stage, the reduction rate was 33% to fully break the austenite grains; in the second stage, in the temperature range of 1000-1050 °C close to the recrystallization stop temperature, two passes of large deformation rolling were adopted, and the third pass The reduction is 20%, the reduction in the fourth pass is 25%, and the cumulative reduction rate of rough rolling is 60%. Rolling in the non-recrystallization area, the cumulative four-pass reduction rate of finish rolling is 58%, and the final rolling temperature is 810-830°C;
D)精轧结束后，通过超快冷+层流冷却，超快冷对钢板快速水冷，水比选择需要兼顾钢板表面硬度不超标，厚板在经过超快冷后因心部温度较高，超快冷后会有所返红，经过后续层流冷却补充，确保终冷温度达到终冷设计温度350～470℃，并控制全板宽方向温度波动≤30℃，防止纵横向力学性能各向异性。D) After finishing rolling, through ultra-fast cooling + laminar cooling, the ultra-fast cooling is used to quickly water-cool the steel plate. The water ratio selection needs to take into account that the surface hardness of the steel plate does not exceed the standard. After the thick plate undergoes ultra-fast cooling, the core temperature is higher. After ultra-fast cooling, it will turn red. After subsequent laminar cooling supplement, ensure that the final cooling temperature reaches the final cooling design temperature of 350-470 ° C, and control the temperature fluctuation in the width direction of the entire board to ≤ 30 ° C to prevent longitudinal and transverse mechanical properties from being different. opposite sex.
按照化学成分的质量百分比设置实施例1～实施例8，具体成分取值如下表：Embodiment 1～Example 8 are set according to the mass percentage of chemical composition, and specific composition takes the following table:
表1实施例1～实施例8的成分取值列表(重量百分比)The composition value list (percentage by weight) of table 1 embodiment 1～embodiment 8
元素组分Elemental composition CC SiSi Mnmn PP SS CrCr NiNi MoMo NbNb TiTi Alal MgMg CaCa
实施例1Example 1 0.0550.055 0.250.25 1.591.59 0.00850.0085 0.00100.0010 0.150.15 0.100.10 0.100.10 0.0560.056 0.0100.010 0.0420.042 ～~ 0.00150.0015
实施例2Example 2 0.0300.030 0.240.24 1.651.65 0.00900.0090 0.00120.0012 0.200.20 0.060.06 0.200.20 0.0530.053 0.0140.014 0.0360.036 ～~ 0.00500.0050
实施例3Example 3 0.0390.039 0.300.30 1.501.50 0.01080.0108 0.00100.0010 0.100.10 0.090.09 0.110.11 0.0700.070 0.0180.018 0.280.28 ～~ 0.00180.0018
实施例4Example 4 0.0500.050 0.180.18 1.451.45 0.01500.0150 0.00080.0008 0.140.14 ～~ 0.110.11 0.0620.062 0.0170.017 0.340.34 ～~ 0.00190.0019
实施例5Example 5 0.0450.045 0.250.25 1.601.60 0.00860.0086 0.00100.0010 ～~ ～~ 0.100.10 0.0600.060 0.0160.016 0.010.01 ～~ 0.00160.0016
实施例6Example 6 0.0440.044 0.190.19 1.501.50 0.00850.0085 0.00150.0015 ～~ ～~ 0.160.16 0.0670.067 0.0250.025 0.180.18 0.00040.0004 0.00040.0004
实施例7Example 7 0.0500.050 0.200.20 1.301.30 0.01030.0103 0.00080.0008 ～~ ～~ 0.100.10 0.0400.040 0.0180.018 0.260.26 0.00070.0007 0.00020.0002
实施例8Example 8 0.0540.054 0.100.10 1.421.42 0.00960.0096 0.00070.0007 ～~ 0.50.5 0.080.08 0.0580.058 0.0160.016 0.410.41 0.00200.0020 0.00030.0003
将上述实施例1～实施例8按照下表的工艺参数进行制造：Above-mentioned embodiment 1～embodiment 8 is manufactured according to the process parameter of following table:
表2实施例1～实施例8的主要工艺参数列表The main process parameter list of table 2 embodiment 1～embodiment 8
Figure PCTCN2022101850-appb-000001
Figure PCTCN2022101850-appb-000001
制得的实施例1～实施例8主要性能如下：The main performances of the obtained embodiment 1 to embodiment 8 are as follows:
表3实施例1～实施例8主要性能Table 3 embodiment 1～embodiment 8 main performance
Figure PCTCN2022101850-appb-000002
Figure PCTCN2022101850-appb-000002
Figure PCTCN2022101850-appb-000003
Figure PCTCN2022101850-appb-000003
通过对8个实施例理化综合性能数据可知，8组实施例综合性能完全能满足X70级管线钢的技术指标要求，具有较好的强韧性，通过H 2S腐蚀检验表明具有良好的抗H 2S腐蚀性能。具有代表性的微观金相组织见附图1。 According to the comprehensive physical and chemical performance data of the 8 examples, the comprehensive performance of the 8 examples can fully meet the technical index requirements of X70 grade pipeline steel, and has good strength and toughness. The H 2 S corrosion test shows that it has good resistance to H 2 S corrosion performance. See Figure 1 for a representative microscopic metallographic structure.
实施例二Embodiment two
以采用炼钢230mm铸坯轧制25.4mmX65级管线为例，具体实施步骤为：Taking the rolling of 25.4mmX65 grade pipelines with steelmaking 230mm cast slabs as an example, the specific implementation steps are as follows:
A)钢水成分合格后，对钢液进行Ca和Mg处理，Mg处理工艺中，钢水中Mg按0.0004～0.0020％控制，Ca处理工艺中，钢水中Ca按0.0018～0.005％控制，浇铸时过热度控制在1530～1550℃；A) After the composition of the molten steel is qualified, the molten steel is treated with Ca and Mg. In the Mg treatment process, the Mg in the molten steel is controlled by 0.0004-0.0020%. In the Ca treatment process, the Ca in the molten steel is controlled by 0.0018-0.005%. The superheat during casting Controlled at 1530～1550℃;
B)浇铸成230mm铸坯后，热装或缓冷后装加热炉，加热温度为1160～1200℃，在炉时间130min～260min，高温1160～1200℃保温时间60～100min；B) After casting into a 230mm slab, install it into a heating furnace after hot charging or slow cooling. The heating temperature is 1160-1200°C, the time in the furnace is 130min-260min, and the holding time at a high temperature of 1160-1200°C is 60-100min;
C)热轧三阶段轧制：第一阶段，在1050℃以上高温奥氏体区进行2道次大变形轧制，第一道次压下率13％，第二道次压下率23％，第一阶段压下率33％使奥氏体晶粒充分破碎；第二阶段，在接近再结晶停止温度的1000～1050℃温度区间内，采用2道次大变形轧制，第三道次压下20％，第四道次压下25％，粗轧累计压下率60％；第三阶段为精轧阶段，控扎控冷设定精轧开轧温度≤950℃，进行奥氏体未再结晶区轧制，精轧累计四道次压下率58％，终轧温度810-830℃；C) Three-stage hot rolling: In the first stage, two passes of large deformation rolling are carried out in the high-temperature austenite zone above 1050°C. The reduction rate of the first pass is 13%, and the reduction rate of the second pass is 23%. In the first stage, the reduction rate was 33% to fully break the austenite grains; in the second stage, in the temperature range of 1000-1050 °C close to the recrystallization stop temperature, two passes of large deformation rolling were adopted, and the third pass The reduction is 20%, the reduction in the fourth pass is 25%, and the cumulative reduction rate of rough rolling is 60%. Rolling in the non-recrystallization area, the cumulative four-pass reduction rate of finish rolling is 58%, and the final rolling temperature is 810-830°C;
D)精轧结束后，通过超快冷+层流冷却，超快冷对钢板快速水冷，水比选择需要兼顾钢板表面硬度不超标，厚板在经过超快冷后 因心部温度较高，超快冷后会有所返红，经过后续层流冷却补充，确保终冷温度达到终冷设计温度400～500℃，并控制全板宽方向温度波动≤30℃，防止纵横向力学性能各向异性。D) After finishing rolling, through ultra-fast cooling + laminar cooling, the ultra-fast cooling is used to quickly water-cool the steel plate. The water ratio selection needs to take into account that the surface hardness of the steel plate does not exceed the standard. After the thick plate undergoes ultra-fast cooling, the core temperature is higher. After ultra-fast cooling, it will turn red. After subsequent laminar cooling supplement, ensure that the final cooling temperature reaches the final cooling design temperature of 400-500 ° C, and control the temperature fluctuation in the width direction of the entire board to ≤ 30 ° C to prevent longitudinal and transverse mechanical properties from being different. opposite sex.
按照化学成分的质量百分比设置实施例9～实施例14，具体成分取值如下表4：Embodiment 9 to Embodiment 14 are set according to the mass percentage of the chemical composition, and the specific composition values are as follows in Table 4:
表4实施例9～实施例4的成分取值列表(重量百分比)The composition value list (percentage by weight) of table 4 embodiment 9～embodiment 4
元素组分Elemental composition CC SiSi Mnmn PP SS MoMo NbNb TiTi Alal MgMg CaCa
实施例9Example 9 0.0550.055 0.250.25 1.351.35 0.0120.012 0.00080.0008 0.080.08 0.0550.055 0.0170.017 0.0350.035 0.00200.0020 0.00360.0036
实施例10Example 10 0.0500.050 0.100.10 1.301.30 0.0130.013 0.00100.0010 0.200.20 0.0500.050 0.0250.025 0.0450.045 0.00040.0004 0.00240.0024
实施例11Example 11 0.0450.045 0.300.30 1.401.40 0.0120.012 0.00090.0009 0.150.15 0.0700.070 0.0180.018 0.0290.029 -- 0.00500.0050
实施例12Example 12 0.0300.030 0.150.15 1.651.65 0.0150.015 0.00150.0015 0.200.20 0.0470.047 0.0150.015 0.0340.034 -- 0.00180.0018
实施例13Example 13 0.0470.047 0.200.20 1.501.50 0.0120.012 0.00090.0009 0.150.15 0.0400.040 0.0100.010 0.0100.010 -- 0.00220.0022
实施例14Example 14 0.0530.053 0.250.25 1.421.42 0.0120.012 0.00090.0009 0.150.15 0.0500.050 0.0170.017 0.0310.031 -- 0.00200.0020
将上述实施例9～实施例14按照下表的工艺参数进行制造：Above-mentioned embodiment 9～embodiment 14 are manufactured according to the process parameter of following table:
表5实施例9～实施例14的主要工艺参数列表The main technological parameter list of table 5 embodiment 9～embodiment 14
Figure PCTCN2022101850-appb-000004
Figure PCTCN2022101850-appb-000004
制得的实施例9～实施例14主要性能如下：The main properties of the obtained embodiment 9 to embodiment 14 are as follows:
表6实施例9～实施例14主要性能Table 6 embodiment 9～embodiment 14 main performance
Figure PCTCN2022101850-appb-000005
Figure PCTCN2022101850-appb-000005
Figure PCTCN2022101850-appb-000006
Figure PCTCN2022101850-appb-000006
通过对实施例(9-14)6个实施例理化综合性能数据可知，6组实施例综合性能完全能满足X65级管线钢指标要求，具有较好的强韧性，且抗H 2S腐蚀性能良好。具有代表性的微观金相组织见附图2，组织类型为粒状贝氏体体+针状铁素体。 According to the physical and chemical comprehensive performance data of the 6 examples of Examples (9-14), it can be known that the comprehensive performance of the 6 examples can fully meet the requirements of the X65 grade pipeline steel index, has good strength and toughness, and has good H 2 S corrosion resistance . The representative microstructure is shown in Figure 2, and the structure type is granular bainite + acicular ferrite.
本发明热连轧极限厚度规格高强管线钢板卷，由于采用合理的成分设计和优化的轧制TMCP生产工艺，可以显著提高厚规格管线钢的强韧性和可生产性，解决现有热连轧极限厚壁管线钢板卷生产技术问题，板卷综合理化性能的Rt 0.5(480～600MPa)，抗拉R m(545～760MPa)，冲击～30℃KV2≥200J，～20℃DWTT SA≥85％，硬度HV10≤250，具有较好的强韧性匹配和低屈强比，尺寸偏差厚度偏差～0.2mm～+0.2mm，塔形≤50mm，能够满足厚度规格X65和X70级管线钢板卷和钢管服役技术要求。 The invention can remarkably improve the strength, toughness and productivity of the thick specification pipeline steel due to the adoption of reasonable composition design and optimized rolling TMCP production process, and solve the problem of existing hot continuous rolling limit. Thick-wall pipeline steel coil production technical issues, comprehensive physical and chemical properties of coil Rt 0.5 (480 ~ 600MPa), tensile R m (545 ~ 760MPa), impact ~ 30 ℃ KV2 ≥ 200J, ~ 20 ℃ DWTT SA ≥ 85%, Hardness HV10≤250, with good strength-toughness matching and low yield ratio, dimensional deviation thickness deviation ~0.2mm～+0.2mm, tower shape≤50mm, can meet the thickness specification X65 and X70 grade pipeline steel coil and steel pipe service technology Require.

Claims (8)

  1. 一种热连轧极限厚度规格高强管线钢板卷，其特征在于：其化学成分的质量百分比为：C:0.030～0.055％，Si：0.10～0.30％，Mn：1.30～1.65％，P：≤0.015％；S：≤0.0015％，Cr：≤0.20％，Ni≤0.10％，Mo：0.08～0.20％，Nb：0.04～0.07％，Ti：0.01～0.025％，Al：0.01～0.045％，余量为Fe。A hot-rolled high-strength pipeline steel coil with extreme thickness specifications, characterized in that: the mass percentage of its chemical composition is: C: 0.030-0.055%, Si: 0.10-0.30%, Mn: 1.30-1.65%, P: ≤0.015 %; S: ≤0.0015%, Cr: ≤0.20%, Ni≤0.10%, Mo: 0.08～0.20%, Nb: 0.04～0.07%, Ti: 0.01～0.025%, Al: 0.01～0.045%, the balance is Fe.
  2. 如权利要求1所述热连轧极限厚度规格高强管线钢板卷，其特征在于：金相组织为粒状贝氏体/针状铁素体和少量小尺寸准多边形铁素体的组织结构。As claimed in claim 1, the hot-rolled high-strength pipeline steel coil with limit thickness specifications is characterized in that the metallographic structure is a structure of granular bainite/acicular ferrite and a small amount of small-sized quasi-polygonal ferrite.
  3. 一种如权利要求1或2所述热连轧极限厚度规格高强管线钢板卷的制造方法，其特征在于：包括如下步骤：A method for manufacturing a hot continuous rolling limit thickness specification high-strength pipeline steel coil according to claim 1 or 2, characterized in that it includes the following steps:
    A)钢水成分合格后，对钢液进行Ca和Mg处理，浇铸时过热度控制在1530～1550℃；A) After the composition of the molten steel is qualified, the molten steel is treated with Ca and Mg, and the degree of superheat is controlled at 1530-1550°C during casting;
    B)浇铸成坯后，热装或缓冷后装加热炉加热保温，加热温度为1160～1200℃，在炉时间130min～260min，高温1160～1200℃，保温时间60～100min；B) After casting into a billet, install it in a heating furnace for heating and heat preservation after hot charging or slow cooling. The heating temperature is 1160-1200°C, the time in the furnace is 130min-260min, the high temperature is 1160-1200°C, and the holding time is 60-100min;
    C)热轧三阶段轧制：第一阶段，在1050℃以上高温奥氏体区进行1～3道次大变形轧制，单道次压下率≥10％，第一阶段压下率≥30％，使奥氏体晶粒充分破碎；第二阶段，在接近再结晶停止温度的1000～1050℃温度区间内，采用2～7道次大变形轧制，单道次压下率≥15％，第二阶段压下率≥30％，使原奥氏体晶粒在较低温度下发生动/静态再结晶，同时抑制再结晶后待温过程中的晶粒长大；第三阶段为精轧阶段，精轧开轧温度≤950℃，进行奥氏体未再结晶区轧制，精轧累计四道次压下率不小于58％，终轧温度810～830℃；C) Three-stage rolling of hot rolling: in the first stage, 1 to 3 passes of large deformation rolling are carried out in the high-temperature austenite zone above 1050°C, the reduction rate of a single pass is ≥10%, and the reduction rate of the first stage is ≥ 30%, so that the austenite grains are fully broken; in the second stage, in the temperature range of 1000-1050 ℃ close to the recrystallization stop temperature, 2-7 passes of large deformation rolling are adopted, and the reduction ratio of a single pass is ≥15 %, the reduction rate in the second stage is ≥ 30%, so that the dynamic/static recrystallization of the original austenite grains occurs at a lower temperature, and at the same time inhibits the grain growth during the warming process after recrystallization; the third stage is In the finishing rolling stage, the starting temperature of finishing rolling is ≤950°C, rolling is carried out in the non-recrystallized zone of austenite, the cumulative reduction ratio of the four passes of finishing rolling is not less than 58%, and the finishing rolling temperature is 810-830°C;
    D)精轧结束后，通过超快冷+层流冷却，超快冷对钢板快速水冷，确保终冷温度达到终冷设计温度350～470℃，并控制全板宽方向 温度波动≤30℃，防止纵横向力学性能各向异性。D) After finishing rolling, through ultra-fast cooling + laminar cooling, the ultra-fast cooling is used to quickly water-cool the steel plate to ensure that the final cooling temperature reaches the final cooling design temperature of 350-470 ° C, and control the temperature fluctuation in the width direction of the entire plate to ≤ 30 ° C, Prevent longitudinal and transverse mechanical property anisotropy.
  4. 如权利要求3所述热连轧极限厚度规格高强管线钢板卷的制造方法，其特征在于：所述步骤A)中，采用电磁搅拌和动态轻压下改善连铸坯偏析，控制铸坯低倍评级在C1.0级以内。As claimed in claim 3, the manufacturing method of hot continuous rolling limit thickness specification high-strength pipeline steel coil is characterized in that: in said step A), electromagnetic stirring and dynamic light reduction are used to improve the continuous casting slab segregation, and to control the low magnification of the casting slab The rating is within C1.0 level.
  5. 如权利要求3所述热连轧极限厚度规格高强管线钢板卷的制造方法，其特征在于：所述步骤A)中，Mg处理工艺中，钢水中Mg按0.0004～0.0020％控制，Ca处理工艺中，钢水中Ca按0.0018～0.005％控制。As claimed in claim 3, the manufacturing method of hot continuous rolling limit thickness specification high-strength pipeline steel coil is characterized in that: in the step A), in the Mg treatment process, the Mg in molten steel is controlled at 0.0004-0.0020%, and in the Ca treatment process , Ca in molten steel is controlled by 0.0018-0.005%.
  6. 如权利要求3所述热连轧极限厚度规格高强管线钢板卷的制造方法，其特征在于：所述步骤B)中，装炉温度控制在450℃以下。The method for manufacturing high-strength pipeline steel coils of hot continuous rolling with extreme thickness specifications according to claim 3, characterized in that: in the step B), the furnace charging temperature is controlled below 450°C.
  7. 如权利要求3所述热连轧极限厚度规格高强管线钢板卷的制造方法，其特征在于：粗轧前对铸坯采用定宽机定宽确保铸坯尺寸精度和边部温度均匀性，高压水除鳞确保带钢表面质量，短行程立辊轧机提高带钢宽度精度，液压微调R2轧机，提高带坯厚度精度，确保了操作稳定性，避免产生镰刀弯；As claimed in claim 3, the method for manufacturing high-strength pipeline steel coils with hot continuous rolling limit thickness specifications is characterized in that: before rough rolling, the cast slab is fixed by a width-setting machine to ensure the dimensional accuracy and edge temperature uniformity of the cast slab, and the high-pressure water Descaling ensures the surface quality of the strip, the short-stroke vertical roll mill improves the strip width accuracy, and the hydraulic fine-tuning of the R2 rolling mill improves the thickness accuracy of the strip, ensuring operational stability and avoiding camber;
  8. 如权利要求3所述热连轧极限厚度规格高强管线钢板卷的制造方法，其特征在于：精轧机采用液压长行程辊缝设定系统及AGC系统控制，通过窜辊、弯辊系统、厚度、凸度及板型测量闭环控制系统实现板型高精度控制，其中，通过辊缝设定系统、窜弯系统和AGC系统获得极小厚度误差和最好精度值，通过神经元网络控制技术提高终轧温度、宽度精度和厚度精度，轧制线表面质量检测系统确保液压活套装置有效控制机架间张力，确保钢表面质量。As claimed in claim 3, the manufacturing method of hot continuous rolling limit thickness specification high-strength pipeline steel coil is characterized in that: the finishing mill is controlled by a hydraulic long-stroke roll gap setting system and an AGC system, through roll shifting, bending system, thickness, The crown and shape measurement closed-loop control system realizes the high-precision control of the shape. Among them, the minimum thickness error and the best precision value are obtained through the roll gap setting system, the bending system and the AGC system, and the neuron network control technology is used to improve the final Rolling temperature, width accuracy and thickness accuracy, the rolling line surface quality inspection system ensures that the hydraulic looper device can effectively control the tension between the stands and ensure the steel surface quality.
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