EP4036267A1 - Komplexer phasenstahl mit hoher lochausdehnbarkeit und verfahren zur herstellung davon - Google Patents

Komplexer phasenstahl mit hoher lochausdehnbarkeit und verfahren zur herstellung davon Download PDF

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Publication number
EP4036267A1
EP4036267A1 EP20869076.8A EP20869076A EP4036267A1 EP 4036267 A1 EP4036267 A1 EP 4036267A1 EP 20869076 A EP20869076 A EP 20869076A EP 4036267 A1 EP4036267 A1 EP 4036267A1
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Prior art keywords
complex
high hole
hole expansibility
phase steel
controlled
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English (en)
French (fr)
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EP4036267A4 (de
Inventor
Chunsu Liu
Yulong Zhang
Siliang Zhang
Feng Yang
Yaping NI
Jintao Wang
Hanlong ZHANG
Ming Wang
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Baoshan Iron and Steel Co Ltd
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Baoshan Iron and Steel Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C47/00—Winding-up, coiling or winding-off metal wire, metal band or other flexible metal material characterised by features relevant to metal processing only
    • B21C47/02—Winding-up or coiling
    • C—CHEMISTRY; METALLURGY
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    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/02—Hardening articles or materials formed by forging or rolling, with no further heating beyond that required for the formation
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    • C21D6/00—Heat treatment of ferrous alloys
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    • 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
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    • 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
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    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
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    • 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
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    • 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
    • C21D8/0242—Flattening; Dressing; Flexing
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    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
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    • 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
    • C21D8/0278—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips involving a particular surface treatment
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    • 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
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
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    • 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
    • C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium 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
    • C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
    • C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
    • C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
    • C23G1/08—Iron or steel
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
    • C23G3/00—Apparatus for cleaning or pickling metallic material
    • C23G3/02—Apparatus for cleaning or pickling metallic material for cleaning wires, strips, filaments continuously
    • 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
    • C21D2211/004—Dispersions; Precipitations
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/005—Ferrite
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
    • C23G3/00—Apparatus for cleaning or pickling metallic material
    • C23G3/02—Apparatus for cleaning or pickling metallic material for cleaning wires, strips, filaments continuously
    • C23G3/027—Associated apparatus, e.g. for pretreating or after-treating

Definitions

  • the present disclosure relates to a steel and a manufacturing method thereof, and particularly relates to a complex-phase steel and a manufacturing method thereof.
  • CN103602895A with the publication date of February 26, 2014 , entitled "high-hole-expansion-ratio steel plate with tensile strength of 780 MPa and manufacturing process thereof', discloses a high-hole-expansion-ratio steel plate with tensile strength of 780 MPa and manufacturing process thereof.
  • the steel plate has a Si content of 0.5-1.5%, which is high, and it is easy to form fayalite (2FeO-SiO 2 ) iron oxide scale which is difficult to remove. It is difficult to obtain strip steel with high-grade surface in this patent application. Meanwhile, because the red iron scale on the surface of the steel plate is difficult to control, it is difficult to measure accurately in the process of hot rolling temperature measurement, resulting in the instability of product performance.
  • CN108570604A with the publication date of September 25, 2018 , entitled "780MPa-level hot-rolled acid-pickled high hole expansion steel tape and production method thereof', discloses a 780MPa-level hot-rolled acid-pickled high hole expansion steel tape and production method thereof.
  • the steel tape has a Al content of 0.2-0.6%, which is high, and easy to be oxidized in the continuous casting process. Meanwhile, a three-stage cooling mode is adopted in this patent application, which has low production stability.
  • CN105483545A with the publication date of April 13, 2016 , entitled "800MPa level hot-rolling high hole expansion steel plate and manufacturing method thereof', discloses an 800MPa level hot-rolling high hole expansion steel plate and manufacturing method thereof.
  • the steel plate has a Si content of 0.2-1.0%, which is relatively high, and it is easy to form red scale on the surface, which is not conducive to the control of surface and coiling temperature. Meanwhile, the steel plate has an Nb content of 0.03-0.08%, which is also relatively high, the cost is high, and sectional cooling is required after rolling, and the cooling process is complex.
  • An object of the present disclosure is to provide a complex-phase steel having high hole expansibility.
  • the complex-phase steel having high hole expansibility can simultaneously satisfy the requirements for good hole expansibility and plasticity, and compared with traditional material like low-alloy high-strength steel and ferrite-martensite dual-phase steel, the two phases of the complex-phase steel having high hole expansibility are ferrite and bainite, so the hardness difference is small, making the steel good hole expansibility and cold formability.
  • the present disclosure provides a complex-phase steel having high hole expansibility, wherein the microstructure of the complex-phase steel is ferrite + bainite, and the mass percentage of chemical elements of the complex-phase steel having high hole expansibility is: C: 0.06-0.09%, Si: 0.05-0.5%, Al: 0.02-0.1%, Mn: 1.5-1.8%, Cr: 0.3-0.6%, Nb ⁇ 0.03%, Ti: 0.05-0.12%, and a balance of Fe and inevitable impurities.
  • the design principle of each chemical element is as follows:
  • C In the complex-phase steel having high hole expansibility of the present disclosure, considering that the carbon content largely determines the tensile strength level of the steel plate, carbon is used for solid solution strengthening and forming sufficient precipitation strengthening phase to ensure the strength of the steel, but the high mass percentage of carbon will make the carbide particles coarse, which is not conducive to the hole expansibility; if the mass percentage of carbon is too low, the strength of the steel plate will be reduced. In order to ensure that the steel can not only have high hole expansibility with strength, but also have good forming and welding performance, in the technical solution of the present disclosure, the mass percentage of C is controlled to be 0.06-0.09%.
  • Si In the complex-phase steel having high hole expansibility of the present disclosure, silicon has a solid solution strengthening effect to improve the strength of the steel sheet. At the same time, the addition of silicon can increase the work hardening rate and the uniform elongation rate and total elongation rate under a given strength, which is helpful to improve the elongation of steel plate sheet. In addition, silicon can also prevent the precipitation of carbide and reduce the appearance of pearlite phase. However, silicon in the steel is easy to form the surface defect of fayalite (2FeO-SiO 2 ) iron oxide scale on the surface of the steel plate, which has a bad impact on the surface quality.
  • fayalite 2FeO-SiO 2
  • the mass percentage of silicon is controlled to be 0.05-0.5%.
  • Al is a deoxidizing element of steel, reduces oxide inclusions in steel and purifies steel quality, and is conducive to improving the formability of steel plate.
  • the high mass percentage of aluminum will produce oxidation and further affect the continuous casting production. Based on this, in the complex-phase steel having high hole expansibility of the present disclosure, the mass percentage of aluminum is controlled to be 0.02-0.1%.
  • Mn In the complex-phase steel having high hole expansibility of the present disclosure, manganese is a solid solution strengthening element. The low mass percentage of manganese will lead to insufficient strength, but the high mass percentage of manganese will reduce the plasticity of steel plate. At the same time, manganese delays pearlite transformation, improves the hardenability of steel, reduces bainite transformation temperature, refines the substructure of steel, ensures the acquisition of lath substructure and renders good formability on the premise of ensuring the tensile strength of products. Based on this, in the complex-phase steel having high hole expansibility of the present disclosure, the mass percentage of manganese is controlled to be 1.5-1.8%.
  • chromium increases the incubation period of pearlite and ferrite in the CCT curve, inhibits the formation of pearlite and ferrite, is conducive to the formation of bainite structure, and finally is conducive to the improvement of strength and hole expansion rate.
  • the mass percentage of chromium is less than 0.15%, it has no significant impact on the CCT curve, but when the mass percentage of Cr is relatively high, it will lead to higher cost. Based on this, in the complex-phase steel having high hole expansibility of the present disclosure, the mass percentage of chromium is controlled to be 0.3-0.6%.
  • Nb In the complex-phase steel having high hole expansibility of the present disclosure, niobium is one of the important precipitation strengthening and fine grain strengthening elements. It exists in the form of fine precipitation after coiling or in the cooling after rolling, and uses precipitation strengthening to improve the strength. At the same time, the existence of niobium is conducive to refining grains, improving strength and toughness, and reducing the strength difference between ferrite and bainite matrix, which is conducive to the improvement of hole expansion rate. However, when the mass percentage of Nb is higher than 0.03%, the strengthening effect of Nb is close to saturation and the cost is high.
  • the mass percentage of Nb is controlled to be Nb ⁇ 0.03%.
  • the mass percentage of Nb can be preferably set to 0.015-0.03%.
  • titanium is one of the important precipitation strengthening and fine grain strengthening elements. Titanium plays two roles in the present disclosure. One is to combine with the impurity element nitrogen in the steel to form TiN. This is because the free nitrogen atom in the steel is unfavorable to the impact toughness of the steel. Adding a small amount of titanium can fix the free nitrogen, which is conducive to the hole expansion rate and the improvement of the impact toughness. The second is to cooperate with niobium to play the best role in refining austenite grains and precipitation strengthening.
  • the mass percentage of Ti should not be too much, which is easy to form TiN with large size, which is unfavorable to the impact toughness of steel. Therefore, in the complex-phase steel having high hole expansibility of the present disclosure, the mass percentage of Ti is controlled to be Ti: 0.05-0.12%.
  • the Nb content is 0.015-0.03%.
  • the inevitable impurity elements should be controlled as low as possible, but considering the cost control and process constraints, the mass percentages can be controlled at P ⁇ 0.03%, S ⁇ 0.02%, and N ⁇ 0.005%.
  • the reason why the mass percentage of N is controlled at N ⁇ 0.005% is that nitrogen reacts with titanium at high temperature to form TiN particle precipitates, and oversized TiN particles will become local deformation microcracks of the steel plate, which will eventually affect the hole expansion rate. Therefore, the nitrogen content in the steel must be controlled.
  • the reason why the mass percentage of P is controlled at P ⁇ 0.03% is that phosphorus in steel is generally solid dissolved in ferrite, which reduces the toughness of steel, but high phosphorus is unfavorable to weldability. At the same time, phosphorus segregation at grain boundary is not conducive to the hole expansion performance of strip steel, so the phosphorus content should be reduced as much as possible.
  • the mass percentage of S is controlled at S ⁇ 0.02% because the sulfur content and the morphology of sulfide are the main factors affecting the formability. The more the number and size of sulfide are, the more unfavorable it is to the hole expansion performance.
  • the mass percentage contents of chemical elements meet at least one of the following formulae: 0.2 % ⁇ Cr ⁇ 0.5 Si + Al ⁇ 0.42 % ; 0.08 % ⁇ 3.3 Nb + Ti ⁇ 0.20 % .
  • 0.2% ⁇ Cr-0.5(Si+Al) ⁇ 0.42% is controlled, so as to move the transformation zone of pearlite and ferrite to the right, delay the transformation of pearlite and ferrite, and be conducive to the formation of bainite phase, so as to achieve the purpose of high strength and high hole expansion.
  • the mass percentages of Nb and Ti are limited to meet 0.08% ⁇ 3.3Nb+Ti ⁇ 0.20%, so as to control the precipitation strengthening of about 100-200MPa, and when a design of high titanium composition is adopted, niobium does not need to be added, and the purpose of high hole expansion and plasticity requirement in the present disclosure can be achieved at the same time, and the purpose of reducing cost can also be achieved.
  • the microstructure has microalloy precipitates, which include (Ti, Nb)C and NbN.
  • the tensile strength Rm is generally 790 ⁇ 850MPa.
  • the transverse tensile strength is ⁇ 780MPa
  • the yield strength is ⁇ 700MPa
  • the punching hole expansion rate is ⁇ 50%.
  • the punching hole expansion rate is ⁇ 70%.
  • the yield strength is ⁇ 730MPa.
  • the transverse tensile strength is ⁇ 8000MPa.
  • the transverse tensile strength is ⁇ 800MPa
  • the yield strength is ⁇ 730MPa
  • the punching hole expansion rate is ⁇ 70%.
  • another object of the present disclosure is to provide a manufacturing method of the above complex-phase steel having high hole expansibility, through which a complex-phase steel having high hole expansibility with good hole expansion performance and cold forming performance can be obtained.
  • the present disclosure provides a method for manufacturing the above complex-phase steel having high hole expansibility, comprising the following steps:
  • the total reduction rate of hot rolling is controlled to be ⁇ 80%; at the same time, the rough rolling is ensured to be rolled in the recrystallization zone and microalloying precipitation in the austenite zone is avoided; the outlet temperature of rough rolling is controlled at 1020-1100 °C; quasi constant speed rolling process is adopted in the finish rolling process, the steel rolling acceleration is ⁇ 0.005m/s 2 , and the speed of finish rolling is controlled at 6-12m/s; the finish rolling temperature is controlled between 840-900°C and the rolling is performed in the non-recrystallization zone to refine the grain and facilitate deformation induced precipitation; on the premise of ensuring the target temperature, constant speed rolling ensures the stability of air cooling time, which is conducive to the control of delay cooling time.
  • the use of front cooling and delay control cooling mode is conducive to grain recovery and microalloy precipitation.
  • the relaxation time is controlled at 0-8s and the laminar cooling rate is controlled at 40-70°C/s mainly by controlling the speed of finish rolling strip and the position of starting valve.
  • a continuous casting process can be adopted, and a superheat, a secondary cooling water and an appropriate soft reduction can be controlled to control the central segregation of the continuous casting slab.
  • a heating temperature is 1200-1260°C.
  • the heating temperature in order to make Ti and Nb fully solid solution, can be set at 1200-1260°C and kept for 1 ⁇ 3h to much better obtain favorable results.
  • the temperature exceeds 1260°C, there will be a trend of grain coarsening, which is not conducive to the toughness of the steel plate; at the same time, the iron oxide scale is thick, which is not conducive to the phosphorus removal of the iron oxide scale. Therefore, the heating temperature is preferably set to 1200-1260°C.
  • a phosphorus removal pressure is controlled to be 15-35MPa.
  • a coiling temperature is 480-560°C.
  • the coiling temperature is controlled at 480-560°C to control bainite transformation and microalloy precipitation.
  • High coiling temperature will lead to more ferrite and pearlite content, which is not conducive to the improvement of hole expansion rate.
  • the coiling temperature is low, the ferrite content is less, the precipitation is less, and martensite structure may appear, and the elongation is low. Therefore, controlling the coiling temperature between 480-560°C can solve the matching problem between elongation and hole expansion rate.
  • a flattening rolling force is controlled to be 100-800 tons, and a flattening elongation meets ⁇ 1.5%.
  • a pickling speed is controlled at 60-100m/min, and a temperature of the last pickling tank in the pickling process is controlled at 80-90°C and an iron ion concentration is controlled at 30-40g/L.
  • the complex-phase steel having high hole expansibility of the present disclosure has the following advantages and beneficial effects:
  • the complex-phase steel having high hole expansibility of the present disclosure can simultaneously satisfy the requirements for good hole expansibility and plasticity, and compared with traditional material like low-alloy high-strength steel and ferrite-martensite dual-phase steel, the two phases of the complex-phase steel having high hole expansibility of the present disclosure are ferrite and bainite, so the hardness difference is small, making the steel have good hole expansibility and cold formability.
  • the manufacturing method of the present disclosure also has the above advantages and beneficial effects.
  • Table 1 shows the mass percentage of each chemical element of the complex-phase steels having high hole expansibility of Examples 1-7 and its manufacturing method and the steel plates of Comparative Examples 1-6.
  • Table 1 (unit: weight %, and a balance of Fe and inevitable impurities other than P, S and N) No C Si Mn Cr Nb Ti Al Cr-0.5 (Si+Al) 3.3Nb+Ti Predicted Rm/MPa
  • Example 1 0.07 0.25 1.65 0.45 0.015 0.08 0.03 0.31 0.13 820
  • Example 2 0.07 0.2 1.77 0.45 0 0.1 0.03 0.34 0.10 832
  • Example 3 0.09 0.12 1.65 0.42 0.03 0.05 0.02 0.35 0.15 797
  • Example 4 0.06 0.5 1.53 0.6 0 0.08 0.08 0.31 0.08 845
  • Example 5 0.07 0.12 1.79 0.3 0.02 0.12 0.04 0.22 0.19 823
  • Example 6 0.06 0.05 1.79 0.45 0.015 0.075 0.02 0.42 0.12 795
  • Table 2 shows the specific process parameters of the complex-phase steels having high hole expansibility of Examples 1-7 and its manufacturing method and the steel plates of Comparative Examples 1-6.
  • Table 2 No. Heating Temperat ure/°C Rough Rolling Outlet Temperat ure/°C Finish rolling speed/m/ s Steel Rolling Accelerat ion/m/s 2 Reductio n Rate/% Finish Rolling Temperat ure/°C Phosphor us Removal Pressure/ MPa Relaxatio n time/s Cooling Rate of Laminar Cooling °C/s Coiling Temperat ure/°C Flattenin g Rolling Force/ton Flattenin g Elongati on Rate/%
  • Example 2 1250 1070 11 0.003 99.0 890 20 3 60 520 223 0.3
  • Table 3 shows the mechanical property test results of the complex-phase steels having high hole expansibility of Examples 1-7 and its manufacturing method and the steel plates of Comparative Examples 1-6.
  • Table 3 Thickness/m m Predicted Rm/MPa Rp0.2/MPa Rm/MPa A50/% ⁇ /% 180° Cold Bending Example 1 3.5 820 742 824 17.5 88 1.5a Example 2 2.2 832 743 833 16.2 87 1.5a
  • Example 3 6.0 797 718 793 18.5 82 1.5a
  • Example 4 5.5 845 706 789 20.1 58 1.5a
  • Example 5 1.8 823 771 859 15.6 78 1.5a
  • Example 6 4.0 795 732 812 15.1 76 1.5a
  • the transverse tensile strength of the complex-phase steel having high hole expansibility of each example of the disclosure is ⁇ 780MPa
  • the yield strength is ⁇ 700MPa
  • the punching hole expansion rate is ⁇ 50%.
  • Comparative Example 4 the heating temperature is relatively low, which is not conducive to the solid solution of Ti and Nb, the precipitation of fine carbides of Nb and Ti in the subsequent cooling and coiling process, and the improvement of strength .
  • a Low coiling temperature is adopted in Comparative Example 5, and there will be a certain amount of martensite in the undercooled structure, which is not conducive to the improvement of elongation and hole expansion rate.
  • a large amount of flatness is adopted in Comparative Example 6, and the elongation loss is 3.4% compared with Example 1.
  • Example 4 Comparing the effects of different surface states of hot rolling on the uniformity of mechanical properties, the composition and process of Example 4 were adopted, and steel strips with different surface states were obtained by setting different phosphorus removal pressure. The worse the surface treatment effect, the greater the surface roughness, the higher the corresponding strength and the lower the elongation.
  • Table 4 lists the effects of different surface states on mechanical properties.
  • Figures 3 and 4 show the morphology of different surface states respectively.
  • Fig. 3 shows the surface morphology of the surface oxide scale of the strip steel with good surface
  • Fig. 4 shows the surface morphology of the surface oxide scale of the strip steel with surface "NG1".
  • Table 4 Thickness/m m Phosphorus Removal Pressure/MPa Surface Roughness/ ⁇ m Rp0.2/MPa Rm/MPa A50/% Good Surface 3.5 20 1.33 706 789 20.1 Surface NG1 3.5 8 4.78 835 897 13.5 Surface NG2 3.5 5 5.34 864 937 11.8 Surface NG3 3.5 9 3.15 760 856 14.5
  • Fig. 1 is the metallographic microstructure photo of the complex-phase steel having high hole expansibility of Example 1.
  • Fig. 2 is the SEM microstructure photo of the complex-phase steel having high hole expansibility of Example 1.
  • microstructure of the complex-phase steel having high hole expansibility of the present disclosure is ferrite + bainite, and the microstructure has microalloy precipitates, which include (Ti, Nb)C and NbN.
  • Fig. 5 illustrates the change of mechanical properties of the complex-phase steel having high hole expansibility of Example 3 under different flattening deformation.
  • the complex-phase steel having high hole expansibility of the present disclosure can simultaneously satisfy the requirements for good hole expansibility and plasticity, and compared with traditional material like low-alloy high-strength steel and ferrite-martensite dual-phase steel, the two phases of the complex-phase steel having high hole expansibility of the present disclosure are ferrite and bainite, so the hardness difference is small, making the steel have good hole expansibility and cold formability.
  • the manufacturing method of the present disclosure also has the above advantages and beneficial effects.
  • combination mode of the technical features in the present disclosure is not limited to the combination mode recorded in the claims or the combination mode recorded in the specific embodiment of the present disclosure. All the technical features recorded in present disclosure can be combined or integrated in any way, unless there is a contradiction between them.

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EP20869076.8A 2019-09-27 2020-09-25 Komplexer phasenstahl mit hoher lochausdehnbarkeit und verfahren zur herstellung davon Pending EP4036267A4 (de)

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ES2906276T3 (es) * 2017-01-20 2022-04-18 thyssenkrupp Hohenlimburg GmbH Producto plano de acero laminado en caliente que está constituido por un acero de fase compleja con estructura predominantemente bainítica y procedimiento para la fabricación de un producto plano de acero de este tipo
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