JP7375179B2 - High hole expandability multi-phase steel and its manufacturing method - Google Patents

High hole expandability multi-phase steel and its manufacturing method Download PDF

Info

Publication number
JP7375179B2
JP7375179B2 JP2022519055A JP2022519055A JP7375179B2 JP 7375179 B2 JP7375179 B2 JP 7375179B2 JP 2022519055 A JP2022519055 A JP 2022519055A JP 2022519055 A JP2022519055 A JP 2022519055A JP 7375179 B2 JP7375179 B2 JP 7375179B2
Authority
JP
Japan
Prior art keywords
hole expandability
rolling
control
dual
phase steel
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
JP2022519055A
Other languages
Japanese (ja)
Other versions
JP2022550329A (en
Inventor
春 粟 劉
玉 龍 張
思 良 張
峰 楊
亜 平 倪
金 涛 王
瀚 龍 張
明 王
Original Assignee
宝山鋼鉄股▲分▼有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 宝山鋼鉄股▲分▼有限公司 filed Critical 宝山鋼鉄股▲分▼有限公司
Publication of JP2022550329A publication Critical patent/JP2022550329A/en
Application granted granted Critical
Publication of JP7375179B2 publication Critical patent/JP7375179B2/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • 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
    • 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
    • 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
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/02—Hardening articles or materials formed by forging or rolling, with no further heating beyond that required for the formation
    • 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
    • C21D11/00—Process control or regulation for heat treatments
    • C21D11/005—Process control or regulation for heat treatments for cooling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/002—Heat treatment of ferrous alloys containing Cr
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/005—Heat treatment of ferrous alloys containing Mn
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/02—Hardening by precipitation
    • 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
    • C21D8/021—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips involving a particular fabrication or treatment of ingot or slab
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226—Hot rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—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
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
    • C—CHEMISTRY; METALLURGY
    • 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
    • C21D8/0278—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips involving a particular surface treatment
    • 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
    • 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
    • C22C38/04—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
    • 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

Description

本発明は鋼種及びその製造方法に関し、特に複相鋼及びその製造方法に関する。 TECHNICAL FIELD The present invention relates to a steel type and a method for manufacturing the same, and more particularly to a multiphase steel and a method for manufacturing the same.

自動車の高強度・軽量化に伴い、コントロールアーム、タイロッド、スプリングシートなどの自動車シャーシ部品に８０ｋｇレベルの熱延酸洗鋼板が使用されるモデルは、ますます増えている。例えば、コントロールアームなどの自動車シャーシ部品は、その成形過程にスタンピング、フランジング、穴拡げなどが含まれるため、強度や伸びだけでなく、穴拡げ性に対してもある程度の要求がある。 As automobiles become stronger and lighter, more and more models are using 80 kg hot-rolled pickled steel plates for automobile chassis parts such as control arms, tie rods, and spring seats. For example, the molding process for automobile chassis parts such as control arms includes stamping, flanging, hole expansion, etc., so there are certain requirements not only for strength and elongation, but also for hole expandability.

公開番号がＣＮ１０３６０２８９５Ａで、公開日が２０１４年２月２６日で、名称が「引張強度７８０ＭＰａレベルの高穴拡げ性鋼板及びその製造方法」の中国特許文献には、抗引張強度７８０ＭＰａレベルの高穴拡げ性鋼板及びその製造方法が開示されたが、そのＳｉ含有量が０．５～１．５％と高く、鉄橄欖石（２ＦｅＯ－ＳｉＯ２）酸化スケールが形成しやすく且つ除去しにくく、高レベルの表面を有する帯鋼を獲得することが困難であった。また、鋼板表面の赤スケールの制御が難しいので、熱間圧延温度測定過程において正確に測定することが難しくなり、製品の不安定な性能に繋がる。 A Chinese patent document with the publication number CN103602895A, the publication date February 26, 2014, and the title "High hole expandability steel plate with tensile strength 780 MPa level and method for manufacturing the same" describes a high hole expandability steel plate with tensile strength 780 MPa level. Expandable steel sheets and methods for manufacturing the same have been disclosed, but their Si content is as high as 0.5 to 1.5%, and ferroolivine (2FeO-SiO 2 ) oxide scales are easily formed and difficult to remove. It was difficult to obtain steel strips with a level surface. In addition, since it is difficult to control the red scale on the surface of the steel plate, it is difficult to accurately measure the hot rolling temperature during the measurement process, leading to unstable product performance.

公開番号がＣＮ１０８５７０６０４Ａで、公開日が２０１８年９月２５日で、名称が「７８０ＭＰａレベルの熱延酸洗高穴拡げ性鋼帯及びその生産方法」の中国特許文献には、７８０ＭＰａレベルの熱延酸洗高穴拡げ性鋼帯及びその生産方法が開示されたが、その成分Ａｌ含有量が０．２～０．６％と高く、連続鋳造の過程において酸化されやすいと共に、それに適用されるのは三段冷却の手段であり、生産の安定性が低い。 The Chinese patent document with the publication number CN108570604A and the publication date September 25, 2018, titled "780 MPa level hot-rolled pickled steel strip with high hole expandability and its production method," states that A pickled steel strip with high hole expandability and a method for producing the same have been disclosed, but the Al content of the steel strip is as high as 0.2 to 0.6%, and it is easily oxidized during the continuous casting process. is a three-stage cooling method and has low production stability.

公開号がＣＮ１０５４８３５４５Ａで、公開日が２０１６年４月１３日で、名称が「８００ＭＰａレベルの熱延高穴拡げ性鋼板及びその製造方法」の中国特許文献には、８００ＭＰａレベルの熱延高穴拡げ性鋼板及びその製造方法が開示されたが、その成分に０．２～１．０％のＳｉが含有され、Ｓｉ含有量が比較的に高く、表面で赤スケールが形成しやすく、表面及び巻取り温度の制御に不利である。また、０．０３～０．０８％のＮｂが含有され、Ｎｂ含有量も比較的に高く、コストが高く、且つ圧延後に段階的冷却が必要であり、冷却プロセスが複雑である。 The Chinese patent document with the publication number CN105483545A and the publication date April 13, 2016, titled "800 MPa level hot-rolled high hole expandability steel plate and method for manufacturing the same," states that However, the composition contains 0.2 to 1.0% Si, and the Si content is relatively high, easily forming red scale on the surface, and causing surface and winding problems. This is disadvantageous for controlling the temperature. In addition, it contains 0.03 to 0.08% Nb, which is relatively high, resulting in high cost and requiring stepwise cooling after rolling, making the cooling process complicated.

従来技術では、材料の強度が高いほど、材料の長さと幅の安定性を制御することが難しくなる。これにより、穴拡げ性と冷間成形性が共に良好で、且つ安定的に製造・生産できる高穴拡げ性複相鋼を得ることが望まれている。 In the prior art, the stronger the material, the more difficult it is to control the length and width stability of the material. Thereby, it is desired to obtain a high hole expandability dual-phase steel that has good hole expandability and cold formability and can be manufactured and produced stably.

本発明の一つの目的は、良好な穴拡げ性と良好な可塑性を両立させることができ、且つ該高穴拡げ性複相鋼の２相はフェライトとベイナイトであるので、従来の材料である低合金高強度鋼やフェライト・マルテンサイト二相鋼に比べて硬度差が小さいことにより、その穴拡げ性と冷間成形性が良好となる高穴拡げ性複相鋼を提供することである。 One object of the present invention is to be able to achieve both good hole expandability and good plasticity, and since the two phases of the high hole expandability dual-phase steel are ferrite and bainite, it is possible to achieve both good hole expandability and good plasticity. It is an object of the present invention to provide a high hole expandability dual phase steel which has a smaller difference in hardness than alloy high strength steels and ferritic/martensitic dual phase steels and has good hole expandability and cold formability.

上記目的を達成するために、本発明は、微細組織がフェライト＋ベイナイトであり、以下の化学元素質量百分率を有する高穴拡げ性複相鋼を提供する。 In order to achieve the above object, the present invention provides a high hole expandability dual-phase steel whose microstructure is ferrite + bainite and has the following chemical element mass percentages:

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％、残部はＦｅ及び他の不可避不純物である。 C: 0.06-0.09%, Si: 0.05-0.5%, Al: 0.02-0.1%, Mn: 1.5-1.8%, Cr: 0.3-0. 0.6%, Nb≦0.03%, Ti: 0.05 to 0.12%, the remainder being Fe and other unavoidable impurities.

本発明に係る高穴拡げ性複相鋼において、各化学元素の設計原理は以下のようである。
Ｃ：本発明にかかる高穴拡げ性複相鋼において、炭素含有量のレベルが鋼板の引張強度レベルを大きく左右し、炭素が固溶強化及び十分な析出強化相の形成に関与し、鋼の強度を確保するが、炭素の質量百分率が高くなると、炭化物粒子が粗大化して穴拡げ性に不利になり、逆に炭素が低すぎると、鋼板の強度の低下に繋がるということを考慮すると、鋼種の強度で高穴拡げ性を確保すると共に、良好な成形性と溶接性をもたらすために、本発明に係る技術方案において、Ｃの質量百分率は０．０６～０．０９％に制御される。 In the high hole expandability multiphase steel according to the present invention, the design principle of each chemical element is as follows.
C: In the high hole expandability dual-phase steel according to the present invention, the level of carbon content greatly influences the tensile strength level of the steel plate, and carbon participates in solid solution strengthening and the formation of sufficient precipitation strengthening phase, However, if the mass percentage of carbon increases, the carbide particles will become coarser, which is detrimental to hole expandability.Conversely, if the carbon content is too low, the strength of the steel sheet will decrease. In order to ensure high hole expandability with a strength of , and to provide good formability and weldability, in the technical solution of the present invention, the mass percentage of C is controlled to 0.06 to 0.09%.

Ｓｉ：本発明にかかる高穴拡げ性複相鋼において、ケイ素は固溶強化の作用を奏して鋼板の強度を向上させると共に、ケイ素の添加により、加工硬化速度及び所定の強度での均一伸びと全伸びを向上させることができ、鋼板の伸びの改善に寄与する。さらに、ケイ素は炭化物の析出を阻止し、パーライト相の出現を低減させることもできる。しかし、鋼にケイ素を含ませると、鋼板の表面は鉄橄欖石（２ＦｅＯ－ＳｉＯ２）酸化スケールの表面欠陥が形成する傾向にあり、表面品質に悪影響を与える。また、赤スケールの出現は、熱間圧延過程での温度制御に不利であるため、最終的に製品性能の安定性に不利な影響を与える。以上のことを踏まえ、本発明にかかる高穴拡げ性複相鋼において、ケイ素の質量百分率は０．０５～０．５％に制御される。 Si: In the high hole expandability multiphase steel according to the present invention, silicon has the effect of solid solution strengthening and improves the strength of the steel plate, and the addition of silicon improves the work hardening rate and uniform elongation at a predetermined strength. It can improve the total elongation and contributes to improving the elongation of the steel sheet. Furthermore, silicon can also prevent the precipitation of carbides and reduce the appearance of pearlite phases. However, when silicon is included in steel, surface defects of iron olivine (2FeO-SiO 2 ) oxide scale tend to form on the surface of the steel sheet, which adversely affects the surface quality. In addition, the appearance of red scale is disadvantageous to temperature control during the hot rolling process, which ultimately has an adverse effect on the stability of product performance. Based on the above, in the high hole expandability dual-phase steel according to the present invention, the mass percentage of silicon is controlled to 0.05 to 0.5%.

Ａｌ：本発明にかかる高穴拡げ性複相鋼において、Ａｌは鋼の脱酸元素であり、鋼における酸化物の介在を低減して鋼を清浄化し、鋼板の成形性の向上に有利であるが、アルミニウムの質量百分率が高くなると、酸化が発生し、さらに連続鋳造生産に影響を及ぼす。以上のことを踏まえ、本発明にかかる高穴拡げ性複相鋼において、Ａｌの質量百分率は０．０２～０．１％に制御される。 Al: In the high hole expandability dual-phase steel according to the present invention, Al is a deoxidizing element for steel, reduces the presence of oxides in the steel, cleans the steel, and is advantageous for improving the formability of the steel sheet. However, when the mass percentage of aluminum increases, oxidation occurs, which further affects continuous casting production. Based on the above, in the high hole expandability dual-phase steel according to the present invention, the mass percentage of Al is controlled to 0.02 to 0.1%.

Ｍｎ：本発明にかかる高穴拡げ性複相鋼において、マンガンは固溶強化元素であり、マンガンの質量百分率が低くなると、強度が不足するが、マンガンの質量百分率が高くなると、鋼板の可塑性が低下する。また、マンガンはパーライト変態を遅延させ、鋼の焼入れ性を向上させ、ベイナイト変態温度を下げ、鋼の下部組織の構造を微細化させ、且つラス下部組織の獲得を確保し、製品の引張強度を確保する前提で、良好な成形性をもたらす。以上のことを踏まえ、本発明にかかる高穴拡げ性複相鋼において、Ｍｎの質量百分率は１．５～１．８％に制御される。 Mn: In the highly expandable multi-phase steel according to the present invention, manganese is a solid solution strengthening element, and when the mass percentage of manganese is low, the strength is insufficient, but when the mass percentage of manganese is high, the plasticity of the steel sheet is reduced. descend. In addition, manganese delays the pearlite transformation, improves the hardenability of steel, lowers the bainite transformation temperature, refines the structure of the steel substructure, and ensures the acquisition of lath substructure, increasing the tensile strength of the product. Provided that this is ensured, good moldability is achieved. Based on the above, the mass percentage of Mn in the high hole expandability dual-phase steel according to the present invention is controlled to 1.5 to 1.8%.

Ｃｒ：本発明にかかる高穴拡げ性複相鋼において、クロムは、ＣＣＴ曲線におけるパーライトとフェライトの潜伏期を延ばし、パーライトとフェライトの形成を抑制し、ベイナイト組織の形成に有利し、最終的に強度と穴拡げ率の向上に有利であるが、クロムの質量百分率が０．１５％未満であると、ＣＣＴ曲線への影響は顕著ではないが、Ｃｒの質量百分率が高くなると、コスト高に繋がる。以上のことを踏まえ、本発明にかかる高穴拡げ性複相鋼において、Ｃｒの質量百分率は０．３～０．６％に制御される。 Cr: In the high hole expandability dual-phase steel according to the present invention, chromium extends the latent period of pearlite and ferrite in the CCT curve, suppresses the formation of pearlite and ferrite, is advantageous for the formation of bainite structure, and ultimately improves the strength. However, if the mass percentage of chromium is less than 0.15%, the influence on the CCT curve is not significant, but as the mass percentage of Cr increases, it leads to higher costs. Based on the above, in the high hole expandability dual-phase steel according to the present invention, the mass percentage of Cr is controlled to 0.3 to 0.6%.

Ｎｂ：本発明にかかる高穴拡げ性複相鋼において、ニオブは重要な析出強化元素と細粒強化元素の一つであり、圧延終了後の冷却中または巻取り後で微細な析出物の形で存在し、析出強化によって強度を向上させる。また、ニオブの存在は、結晶粒の微細化、強度や靭性の向上に有利であると共に、フェライトとベイナイトのマトリックス間の強度差を低減させることにより、穴拡げ率の向上にも有利であるが、Ｎｂの質量百分率が０．０３％を超えると、Ｎｂによる強化効果は飽和に近づき、且つコストが高くなる。よって、本発明にかかる高穴拡げ性複相鋼において、Ｎｂの質量百分率はＮｂ≦０．０３％に制御される。Ｎｂの質量百分率が０．０１５％未満であると、ＮｂＣの析出が不十分となり、析出強化の目的が達成しにくいことを考慮すると、いくつかの好ましい実施形態において、Ｎｂの質量百分率は０．０１５～０．０３％に好ましく設定しても良い。 Nb: In the high hole expandability dual-phase steel according to the present invention, niobium is one of the important precipitation strengthening elements and fine grain strengthening elements, and it forms fine precipitates during cooling after rolling or after coiling. It is present in the steel and improves strength through precipitation strengthening. In addition, the presence of niobium is advantageous in making crystal grains finer and improving strength and toughness, as well as in improving the hole expansion rate by reducing the strength difference between the ferrite and bainite matrices. , when the mass percentage of Nb exceeds 0.03%, the reinforcing effect by Nb approaches saturation and the cost increases. Therefore, in the highly expandable dual-phase steel according to the present invention, the mass percentage of Nb is controlled to be Nb≦0.03%. If the mass percentage of Nb is less than 0.015%, the precipitation of NbC will be insufficient and the purpose of precipitation strengthening will be difficult to achieve. It may be preferably set to 0.015% to 0.03%.

Ｔｉ：本発明にかかる高穴拡げ性複相鋼において、チタンは重要な析出強化元素と細粒強化元素の一つであり、本願におけるチタンは以下の２つの役割を果たす：１つ目は鋼中の不純物元素の窒素と結合してＴｉＮを形成することであり、これは、鋼におけるフリーな窒素原子が鋼の衝撃靭性に不利であるので、微量のチタンの添加によりフリーな窒素を固定化し、穴拡げ性の発揮及び衝撃靭性の向上に有利であるからである；２つ目はニオブと協力してオーステナイト結晶粒微細化及び析出強化に最適の役割を果たすことである。しかし、本願において、Ｔｉの質量百分率が多すぎると、サイズが大きなＴｉＮが形成しやすく、鋼の衝撃靭性に不利であるため、望ましくない。よって、本発明にかかる高穴拡げ性複相鋼において、Ｔｉの質量百分率はＴｉ：０．０５～０．１２％に制御される。 Ti: In the high hole expandability multiphase steel according to the present invention, titanium is one of the important precipitation strengthening elements and fine grain strengthening elements, and titanium in the present application plays the following two roles: the first is to strengthen the steel. This is because free nitrogen atoms in steel are disadvantageous to the impact toughness of steel, so the addition of a small amount of titanium fixes free nitrogen. This is because it is advantageous for exhibiting hole expandability and improving impact toughness; secondly, it plays an optimal role in austenite grain refinement and precipitation strengthening in cooperation with niobium. However, in the present application, if the mass percentage of Ti is too large, TiN with a large size tends to be formed, which is disadvantageous for the impact toughness of the steel, which is not desirable. Therefore, in the highly expandable dual-phase steel according to the present invention, the mass percentage of Ti is controlled to 0.05 to 0.12% Ti.

さらに、本発明にかかる高穴拡げ性複相鋼において、Ｎｂ元素の含有量は０．０１５～０．０３％である。 Further, in the high hole expandability dual-phase steel according to the present invention, the content of Nb element is 0.015 to 0.03%.

さらに、本発明にかかる高穴拡げ性複相鋼において、他の不可避不純物では、Ｐ≦０．０３％、Ｓ≦０．０２％、Ｎ≦０．００５％である。 Further, in the high hole expandability dual-phase steel according to the present invention, other unavoidable impurities satisfy the following conditions: P≦0.03%, S≦0.02%, and N≦0.005%.

上記形態において、不可避不純物元素は可能な限り低く制御するべきであるが、コスト管理やプロセスの制限などを考慮すると、Ｐ≦０．０３％、Ｓ≦０．０２％、Ｎ≦０．００５％と制御しても良い。ただし、Ｎの質量百分率がＮ≦０．００５％に制御されるのは、窒素が高温条件下でチタンと反応してＴｉＮ粒子として析出し、大きすぎるＴｉＮ粒子が鋼板の局所変形マイクロクラックになり、最終的に穴拡げ率に影響を及ぼすので、鋼における窒素含有量を制御しなければならないからである。 In the above form, unavoidable impurity elements should be controlled as low as possible, but considering cost management and process limitations, P≦0.03%, S≦0.02%, N≦0.005%. It may also be controlled. However, the reason why the mass percentage of N is controlled to N≦0.005% is because nitrogen reacts with titanium under high temperature conditions and precipitates as TiN particles, and excessively large TiN particles cause local deformation microcracks in the steel sheet. This is because the nitrogen content in the steel must be controlled as it ultimately affects the hole expansion rate.

Ｐについて、Ｐの質量百分率がＰ≦０．０３％に制御されるのは、鋼におけるリンは通常、フェライト中に固溶して鋼の靭性を低下させるが、高レベルのリンは溶接性に不利であると共に、リンは結晶粒界に偏在して帯鋼の穴拡げ性に不利であるので、リン含有量はできるだけ低減させるべきだからである。 Regarding P, the mass percentage of P is controlled to P≦0.03% because phosphorus in steel is usually dissolved in ferrite and reduces the toughness of steel, but high levels of phosphorus impair weldability. This is because, in addition to being disadvantageous, phosphorus is unevenly distributed at grain boundaries and is disadvantageous to the hole expandability of the steel strip, so the phosphorus content should be reduced as much as possible.

上記形態において、Ｓの質量百分率がＳ≦０．０２％に制御されるのは、硫の含有量及び硫化物の形態が成形性に影響する主要な要因であり、硫化物の量が多くてサイズが大きくなるほど、穴拡げ性に不利になるからである。 In the above form, the mass percentage of S is controlled to S≦0.02% because the sulfur content and the form of sulfide are the main factors that affect the formability. This is because the larger the size, the more disadvantageous the hole expandability becomes.

さらに、本発明にかかる高穴拡げ性複相鋼において、その化学元素質量百分率含有量は、下記の各式の少なくとも一つを満たす：
０．２％≦Ｃｒ－０．５（Ｓｉ＋Ａｌ）≦０．４２％；
０．０８％≦３．３Ｎｂ＋Ｔｉ≦０．２０％。 Furthermore, in the high hole expandability dual-phase steel according to the present invention, the chemical element mass percentage content satisfies at least one of the following formulas:
0.2%≦Cr-0.5(Si+Al)≦0.42%;
0.08%≦3.3Nb+Ti≦0.20%.

上記形態において、０．２％≦Ｃｒ－０．５（Ｓｉ＋Ａｌ）≦０．４２％と制御されることにより、パーライトとフェライトの変態領域が右にシフトし、パーライトとフェライトの変態が遅延され、ベイナイト相の形成に有利であることから、高強度と高穴拡げ性の目的を実現できる。 In the above embodiment, by controlling 0.2%≦Cr-0.5(Si+Al)≦0.42%, the transformation region of pearlite and ferrite shifts to the right, and the transformation of pearlite and ferrite is delayed. Since it is advantageous for the formation of a bainite phase, the objectives of high strength and high hole expandability can be achieved.

また、本技術方案において、Ｎｂ、Ｔｉの質量百分率が０．０８％≦３．３Ｎｂ＋Ｔｉ≦０．２０％を満たすように制御されることにより、析出強化が約１００～２００ＭＰａに制御されると共に、高レベルチタン成分の設計を採用する場合に、ニオブを添加せずに、本願に要求される高穴拡げ性と高可塑性の目的を実現できると同時に、コストダウンの目的も実現できる。 In addition, in this technical solution, by controlling the mass percentage of Nb and Ti to satisfy 0.08%≦3.3Nb+Ti≦0.20%, precipitation strengthening is controlled to about 100 to 200 MPa, and When adopting a design with a high level titanium component, the objectives of high hole expandability and high plasticity required in the present application can be achieved without adding niobium, and at the same time, the objective of cost reduction can also be achieved.

さらに、本発明にかかる高穴拡げ性複相鋼において、その微細組織には、（Ｔｉ，Ｎｂ）Ｃ及びＮｂＮを含む微量合金析出物がある。 Furthermore, in the highly expandable dual-phase steel according to the present invention, the microstructure includes trace alloy precipitates containing (Ti, Nb)C and NbN.

さらに、本発明にかかる高穴拡げ性複相鋼において、その引張強度及び化学元素質量百分率含有量は、以下の式を満たす：
引張強度Ｒｍ＝３４３＋７８９×Ｃ＋１７０×Ｓｉ＋１３２×Ｍｎ＋１９５×Ｃｒ＋８４３×（Ｎｂ＋Ｔｉ）－２０７×Ａｌ、引張強度Ｒｍの次元はＭＰａである。 Furthermore, in the high hole expandability dual-phase steel according to the present invention, its tensile strength and chemical element mass percentage content satisfy the following formula:
Tensile strength Rm=343+789×C+170×Si+132×Mn+195×Cr+843×(Nb+Ti)−207×Al, and the dimension of tensile strength Rm is MPa.

本技術方案において、上記の式と本願の化学元素成分配合により、引張強度Ｒｍは通常７９０～８５０ＭＰａである。 In this technical solution, according to the above formula and the chemical element composition of the present application, the tensile strength Rm is usually 790-850 MPa.

さらに、本発明にかかる高穴拡げ性複相鋼において、その幅方向引張強度が≧７８０ＭＰａで、降伏強度が≧７００ＭＰａで、伸びＡ５０が≧１５％で、抜き穴の穴拡げ率が≧５０％である。 Furthermore, in the high hole expandability multi-phase steel according to the present invention, the tensile strength in the width direction is ≧780 MPa, the yield strength is ≧700 MPa, the elongation A50 is ≧15%, and the hole expansion rate of punched holes is ≧50%. It is.

好ましくは、本発明にかかる高穴拡げ性複相鋼において、抜き穴の穴拡げ率が≧７０％である。 Preferably, in the high hole expandability dual-phase steel according to the present invention, the hole expansion rate of the punched holes is ≧70%.

好ましくは、本発明にかかる高穴拡げ性複相鋼において、降伏強度が≧７３０ＭＰａである。 Preferably, in the high hole expandability dual phase steel according to the present invention, the yield strength is ≧730 MPa.

好ましくは、本発明にかかる高穴拡げ性複相鋼において、幅方向引張強度が≧８０００ＭＰａである。 Preferably, in the high hole expandable dual-phase steel according to the present invention, the tensile strength in the width direction is ≧8000 MPa.

好ましくは、本発明にかかる高穴拡げ性複相鋼において、その幅方向引張強度が≧８００ＭＰａで、降伏強度が≧７３０ＭＰａで、伸びＡ５０が≧１５％で、抜き穴の穴拡げ率が≧７０％である。 Preferably, in the high hole expandability multiphase steel according to the present invention, the tensile strength in the width direction is ≧800 MPa, the yield strength is ≧730 MPa, the elongation A50 is ≧15%, and the hole expansion rate of punched holes is ≧70. %.

相応に、本発明のもう一つの目的は、穴拡げ性と冷間成形性が良好な高穴拡げ性複相鋼を獲得できる前記の高穴拡げ性複相鋼の製造方法を提供することである。 Correspondingly, another object of the present invention is to provide a method for producing the above-mentioned highly expandable dual-phase steel, which can obtain a highly expandable dual-phase steel with good hole expandability and cold formability. be.

上記発明目的を達成するために、本発明によって提供される前記の高穴拡げ性複相鋼の製造方法は、以下の工程を含む：
（１）製錬・鋳造；
（２）加熱；
（３）熱間圧延：総圧下率を≧８０％に制御し、粗圧延が再結晶領域で行われるように制御し、粗圧延出口温度を１０２０～１１００℃に制御する；仕上圧延過程に準定速圧延プロセスを適用し、仕上圧延速度を６～１２ｍ／ｓに制御し、鋼材圧延加速度を≦０．００５ｍ／ｓ２に制御する；仕上圧延温度を８４０～９００℃に制御する；
（４）脱リン；
（５）層流冷却：緩和時間を０～８ｓに制御し、層流冷却速度を４０～７０℃／ｓに制御する；
（６）巻取り；
（７）平坦化；
（８）酸洗。 In order to achieve the above objects of the invention, the method of manufacturing the high hole expandability dual-phase steel provided by the present invention includes the following steps:
(1) Smelting and casting;
(2) Heating;
(3) Hot rolling: Control the total rolling reduction to ≧80%, control the rough rolling to occur in the recrystallization region, and control the rough rolling outlet temperature to 1020-1100°C; similar to the finish rolling process. Apply a constant speed rolling process, control the finishing rolling speed to 6~12m/s, and control the steel rolling acceleration to ≦0.005m/ s2 ; control the finishing rolling temperature to 840~900°C;
(4) Dephosphorization;
(5) Laminar cooling: control the relaxation time to 0 to 8 s, and control the laminar cooling rate to 40 to 70°C/s;
(6) Winding;
(7) Flattening;
(8) Pickling.

本発明にかかる製造方法において、熱間圧延の総圧下率を≧８０％に制御する；粗圧延が再結晶領域で行われることを確保すると共に、オーステナイト領域での微量合金析出を回避する；粗圧延出口温度を１０２０～１１００℃に制御する；仕上圧延過程に準定速圧延プロセスを適用し、鋼材圧延加速度を≦０．００５ｍ／ｓ２に制御し、仕上圧延速度を６～１２ｍ／ｓに制御する；仕上圧延温度を８４０～９００℃の間に制御し、未再結晶領域で圧延を行うことで、結晶粒を微細化させると共に、変形誘起析出にも有利である；標的温度を確保する前提で、定速圧延時の安定した空冷時間を確保し、緩和冷却時間の制御に有利である。 In the manufacturing method according to the present invention, the total reduction rate of hot rolling is controlled to ≧80%; ensuring that rough rolling is performed in the recrystallization region and avoiding trace alloy precipitation in the austenite region; Control the rolling exit temperature at 1020-1100°C; Apply a quasi-constant speed rolling process to the finish rolling process, control the steel rolling acceleration to ≦0.005 m/s 2 , and set the finish rolling speed to 6-12 m/s. Control; By controlling the finish rolling temperature between 840 and 900°C and rolling in the non-recrystallized region, it is possible to refine the grains and also be advantageous for deformation-induced precipitation; ensure the target temperature As a prerequisite, it is advantageous to ensure a stable air cooling time during constant speed rolling and control the relaxation cooling time.

また、層流冷却において、前段冷却と緩和制御冷却モードの適用は、結晶粒の回復と微量合金の析出に有利であり、主に仕上圧延帯鋼の速度と開始バルブの位置を制御することで、緩和時間を０～８ｓに制御し、層流冷却速度を４０～７０℃／ｓに制御する。 In addition, in laminar flow cooling, the application of pre-cooling and relaxation control cooling mode is advantageous for the recovery of grains and precipitation of trace alloys, mainly by controlling the speed of finish rolling strip steel and the position of the starting valve. , the relaxation time is controlled to 0 to 8 s, and the laminar cooling rate is controlled to 40 to 70° C./s.

また、いくつかの好ましい実施形態において、連続鋳造プロセスを適用し、且つ過熱度と二次冷却水を制御し、並びに適切に軽圧下することにより、連続鋳造スラブの中心偏析を制御しても良い。 Also, in some preferred embodiments, center segregation of continuously cast slabs may be controlled by applying a continuous casting process and controlling the degree of superheating and secondary cooling water, as well as appropriate light reduction. .

さらに、本発明にかかる製造方法において、工程（２）では、加熱温度を１２００～１２６０℃にする。 Further, in the manufacturing method according to the present invention, in step (2), the heating temperature is set to 1200 to 1260°C.

上記形態において、ＴｉとＮｂを十分に固溶させる目的を考慮すると、より有利な効果を得るように、加熱温度を１２００～１２６０℃に設定し、且つ１～３時間保温しても良い。温度が１２６０℃を超えると、結晶粒が粗大化する傾向にあり、鋼板の靭性に不利であると共に、酸化スケールが厚くなり、酸化スケールからの脱リンに不利であることから、加熱温度を１２００～１２６０℃に設定することが好ましい。 In the above embodiment, considering the purpose of sufficiently dissolving Ti and Nb in solid solution, the heating temperature may be set at 1200 to 1260° C. and kept at a temperature of 1 to 3 hours in order to obtain a more advantageous effect. If the temperature exceeds 1260°C, the crystal grains tend to become coarser, which is disadvantageous to the toughness of the steel plate, and the oxide scale becomes thicker, which is disadvantageous to dephosphorization from the oxide scale. It is preferable to set the temperature to 1260°C.

さらに、本発明にかかる製造方法において、工程（４）では、脱リン圧力を１５～３５ＭＰａに制御する。 Furthermore, in the production method according to the present invention, in step (4), the dephosphorization pressure is controlled to 15 to 35 MPa.

上記形態において、鉄橄欖石（２ＦｅＯ－ＳｉＯ２）が鋼の緻密なスケール層に繋がり、熱間圧延された表面の酸化スケールからの脱リン効果がよくない場合、壊れた酸化スケールの表面の大きな粗さの原因で、層流冷却過程における水の流れが減り、水が局所に貯え、さらに帯鋼の局所性能に影響を与え、帯鋼の局所冷却が影響を受けて不均一となることを考慮すると、脱リン効果がよくないことにより、材料の表面にバラツキが出てくるだけでなく、特性にもバラツキが出てくることから、これに基づいて高圧脱リン水系を好ましく適用することができ、且つ脱リン圧力を１５～３５ＭＰａに制御することができる。 In the above form, ferruginous olivine (2FeO-SiO 2 ) leads to a dense scale layer of steel, and if the dephosphorization effect from the oxide scale on the hot-rolled surface is not good, the surface of the broken oxide scale is large. Due to the roughness, the water flow in the laminar cooling process is reduced, and the water is locally stored, which further affects the local performance of the steel strip, and the local cooling of the steel strip is affected and becomes non-uniform. Taking this into consideration, poor dephosphorization effects not only cause variations in the surface of the material, but also variations in properties, so based on this, it is recommended to apply a high-pressure dephosphorization water system. In addition, the dephosphorization pressure can be controlled to 15 to 35 MPa.

さらに、本発明にかかる製造方法において、工程（６）では、巻取り温度を４８０～５６０℃にする。 Further, in the manufacturing method according to the present invention, in step (6), the winding temperature is set at 480 to 560°C.

上記形態において、巻取り温度を４８０～５６０℃に制御することで、ベイナイト変態と微量合金析出を制御する。ただし、巻取り温度が高くなると、フェライトとパーライトの含有量が多くなり、穴拡げ率の向上に不利であるが、巻取り温度が低くなると、フェライトの含有量が少なくなると共に、析出量も少なくなり、且つマルテンサイト組織が現れる可能性があり、伸びも低くなる。よって、巻取り温度を４８０～５６０℃の間に制御することで、伸びと穴拡げ率のマッチングの問題を解決できる。 In the above embodiment, bainite transformation and trace alloy precipitation are controlled by controlling the winding temperature to 480 to 560°C. However, as the winding temperature increases, the content of ferrite and pearlite increases, which is disadvantageous to improving the hole expansion rate. However, as the winding temperature decreases, the ferrite content decreases and the amount of precipitation decreases. In addition, there is a possibility that a martensitic structure will appear, and the elongation will be low. Therefore, by controlling the winding temperature between 480 and 560° C., the problem of matching elongation and hole expansion rate can be solved.

さらに、本発明にかかる製造方法において、工程（７）では、平坦化圧延力を１００～８００トンに制御し、且つ平坦化伸びが≦１．５％を満たす。 Further, in the manufacturing method according to the present invention, in step (7), the flattening rolling force is controlled to 100 to 800 tons, and the flattening elongation satisfies ≦1.5%.

いくつかの好ましい実施形態において、工程（８）では、酸洗速度を６０～１００ｍ／ｍｉｎに制御し、酸洗過程における最終の酸洗槽の温度を８０～９０℃に制御し、鉄イオン濃度を３０～４０ｇ／Ｌに制御する。 In some preferred embodiments, in step (8), the pickling speed is controlled at 60 to 100 m/min, the temperature of the final pickling tank in the pickling process is controlled at 80 to 90°C, and the iron ion concentration is control at 30 to 40 g/L.

本発明に係る高穴拡げ性複相鋼は、以下のような利点及び有益な効果を有する：
本発明にかかる高穴拡げ性複相鋼は、良好な穴拡げ性と良好な可塑性を両立させることができ、且つ本願にかかる高穴拡げ性複相鋼の２相はフェライトとベイナイトであるので、従来の材料である低合金高強度鋼やフェライト・マルテンサイト二相鋼に比べて硬度差が小さいことにより、その穴拡げ性と冷間成形性が良好となる。 The high hole expandability dual-phase steel according to the present invention has the following advantages and beneficial effects:
The high hole expandability dual phase steel according to the present invention can have both good hole expandability and good plasticity, and the two phases of the high hole expandability dual phase steel according to the present invention are ferrite and bainite. Since the difference in hardness is smaller than that of conventional materials such as low-alloy high-strength steel and ferrite-martensitic dual-phase steel, its hole expandability and cold formability are good.

また、本発明にかかる製造方法も同じく、上記の利点及び有益な効果を有する。 Moreover, the manufacturing method according to the present invention also has the above-mentioned advantages and beneficial effects.

図１は、実施例１にかかる高穴拡げ性複相鋼の金属ミクロ組織図である。FIG. 1 is a metal microstructure diagram of the highly expandable multiphase steel according to Example 1. 図２は、実施例１にかかる高穴拡げ性複相鋼のＳＥＭミクロ組織図である。FIG. 2 is an SEM microstructure diagram of the high hole expandability dual-phase steel according to Example 1. 図３は、表面が良好な帯鋼の表面酸化スケールの表面プロファイルを示す。FIG. 3 shows the surface profile of the surface oxidation scale of a steel strip with a good surface. 図４は、表面がＮＧ１の帯鋼の表面酸化スケールの表面プロファイルを示す。FIG. 4 shows the surface profile of the surface oxidation scale of a steel strip with an NG1 surface. 図５は、実施例３にかかる高穴拡げ性複相鋼の、異なる平坦化変形量での力学的特性の変化を示す。FIG. 5 shows changes in mechanical properties of the high hole expandability multiphase steel according to Example 3 at different amounts of flattening deformation.

以下、図面及び具体的な実施例に基づいて、本発明にかかる高穴拡げ性複相鋼及びその製造方法をさらに解釈・説明するが、該解釈・説明は本発明の技術方案を不当に制限するものではない。 Hereinafter, the high hole expandability multiphase steel and the manufacturing method thereof according to the present invention will be further interpreted and explained based on the drawings and specific examples, but such interpretation and explanation will unduly limit the technical solution of the present invention. It's not something you do.

実施例１～７及び比較例１～６
上記実施例１～７にかかる高穴拡げ性複相鋼及びその製造方法、並びに比較例１～６にかかる比較鋼板は、以下の工程によって調製された：
（１）表１に示す化学成分に従って製錬・鋳造し、転炉で製錬し、溶鋼をＲＨで真空脱ガス処理し、ＬＦ炉で脱硫処理し、ただし、Ｐ≦０．０１５％、Ｓ≦０．００５％のように制御した。連続鋳造の際は、過熱度と二次冷却水を制御し、並びに適切に軽圧下することにより、連続鋳造スラブの中心偏析を制御した。 Examples 1 to 7 and Comparative Examples 1 to 6
The high hole expandability dual-phase steels and manufacturing methods thereof according to Examples 1 to 7, and the comparative steel plates according to Comparative Examples 1 to 6 were prepared by the following steps:
(1) Smelting and casting according to the chemical composition shown in Table 1, smelting in a converter, vacuum degassing treatment of molten steel in RH, and desulfurization treatment in LF furnace, provided that P≦0.015%, S It was controlled to be ≦0.005%. During continuous casting, the center segregation of the continuously cast slab was controlled by controlling the degree of superheating, secondary cooling water, and appropriate light reduction.

（２）加熱：加熱温度を１２００～１２６０℃にした。
（３）熱間圧延：総圧下率を≧８０％に制御し、粗圧延が再結晶領域で行われるように制御し、粗圧延出口温度を１０２０～１１００℃に制御した；仕上圧延過程に準定速圧延プロセスを適用し、仕上圧延速度を６～１２ｍ／ｓに制御し、鋼材圧延加速度を≦０．００５ｍ／ｓ２に制御した；仕上圧延温度を８４０～９００℃に制御した。 (2) Heating: The heating temperature was 1200 to 1260°C.
(3) Hot rolling: The total rolling reduction was controlled to ≧80%, the rough rolling was controlled to be performed in the recrystallization region, and the rough rolling exit temperature was controlled to 1020-1100°C; similar to the finish rolling process. A constant speed rolling process was applied, the finishing rolling speed was controlled at 6-12 m/s, the steel rolling acceleration was controlled at ≦0.005 m/ s2 ; the finishing rolling temperature was controlled at 840-900°C.

（４）脱リン：脱リン圧力を１５～３５ＭＰａに制御した。
（５）層流冷却：緩和時間を０～８ｓに制御し、層流冷却速度を４０～７０℃／ｓに制御した。 (4) Dephosphorization: The dephosphorization pressure was controlled at 15 to 35 MPa.
(5) Laminar cooling: The relaxation time was controlled to 0 to 8 s, and the laminar cooling rate was controlled to 40 to 70° C./s.

（６）巻取り：巻取り温度を４８０～５６０℃にした。
（７）平坦化：平坦化圧延力を１００～８００トンに制御し、且つ平坦化伸びが≦１．５％を満たした。 (6) Winding: The winding temperature was set at 480 to 560°C.
(7) Flattening: The flattening rolling force was controlled to 100 to 800 tons, and the flattening elongation satisfied ≦1.5%.

（８）酸洗：酸洗速度を６０～１００ｍ／ｍｉｎに制御し、酸洗過程における最終の酸洗槽の温度を８０～９０℃に制御し、鉄イオン濃度を３０～４０ｇ／Ｌに制御した。 (8) Pickling: Control the pickling speed to 60-100 m/min, control the temperature of the final pickling tank in the pickling process to 80-90°C, and control the iron ion concentration to 30-40 g/L. did.

実施例１～７にかかる高穴拡げ性複相鋼及びその製造方法、並びに比較例１～６における各化学元素の質量百分率配合は表１に示す。 Table 1 shows the high hole expandability dual-phase steels of Examples 1 to 7 and their manufacturing methods, as well as the mass percentage composition of each chemical element in Comparative Examples 1 to 6.

実施例１～７にかかる高穴拡げ性複相鋼及びその製造方法、並びに比較例１～６にかかる比較鋼板の具体的なプロセスパラメーターは表２に示す。 Table 2 shows the specific process parameters of the high-hole-expandable dual-phase steels of Examples 1 to 7 and their manufacturing methods, as well as the comparative steel plates of Comparative Examples 1 to 6.

ＩＳＯ／ＤＩＳ１６６３０規格に準拠した穴広げ率計測方法に従い、試験片サンプルのサイズを１５０×１５０ｍｍにし、抜き穴のサイズをΦ１０ｍｍにし、クリアランスを１２．５％にし、６０°の円錐パンチを用いてせん断面から穴を広げ、き裂が板厚を貫通した時点の内径ｄを求めた。穴拡げ前の内径をｄ０とすると、下式から限界穴拡げ値λ％を求めた。限界穴拡げ値λ％＝（ｄ－ｄ０）／ｄ０×１００％。引張規格は、幅方向のＪＩＳ ５＃引張試験片を採取し、力学的特性を測定した；１８０°曲げ特性は、ＧＢ／Ｔ２３２－２０１０規格に準拠して実施された。 According to the hole expansion rate measurement method based on the ISO/DIS16630 standard, the test piece sample size was 150 x 150 mm, the hole size was Φ10 mm, the clearance was 12.5%, and a 60° conical punch was used. The hole was enlarged from the cross section, and the inner diameter d at the time when the crack penetrated through the plate thickness was determined. Assuming that the inner diameter before hole expansion is d0 , the limit hole expansion value λ% was determined from the formula below. Limit hole expansion value λ% = (d-d 0 )/d 0 ×100%. For tensile specifications, JIS 5# tensile test pieces in the width direction were taken and mechanical properties were measured; 180° bending properties were conducted in accordance with the GB/T232-2010 standard.

実施例１～７にかかる高穴拡げ性複相鋼及びその製造方法、並びに比較例１～６にかかる比較鋼板の力学的特性の計測結果は表３に示す。 Table 3 shows the measurement results of the mechanical properties of the high hole expandability dual-phase steels according to Examples 1 to 7 and their manufacturing methods, and the comparative steel plates according to Comparative Examples 1 to 6.

表３から分かるように、本願の各実施例にかかる高穴拡げ性複相鋼において、その幅方向引張強度が≧７８０ＭＰａで、降伏強度が≧７００ＭＰａで、伸びＡ５０が≧１５％で、抜き穴の穴拡げ率が≧５０％であった。 As can be seen from Table 3, the high hole expandability multiphase steel according to each example of the present application has a tensile strength in the width direction of ≧780 MPa, a yield strength of ≧700 MPa, an elongation A50 of ≧15%, and a punched hole. The hole expansion rate was ≧50%.

表１も併せて見れば分かるように、比較例１において、Ｃｒ－０．５（Ｓｉ＋Ａｌ）が０．２％≦Ｃｒ－０．５（Ｓｉ＋Ａｌ）≦０．４２％の要件を満たしておらず、実施例１に比べると、両者は同じプロセスを適用したが、比較例１のほうは、Ｓｉ含有量が高く、鉄橄欖石（２ＦｅＯ－ＳｉＯ２）酸化スケールが形成しやすく且つ除去しにくく、高レベルの表面を有する帯鋼を獲得することが困難であったと共に、表面の赤スケールの制御が難しいので、熱間圧延温度測定過程において正確に測定することが難しくなり、製品の不安定な性能に繋がり、鉄橄欖石（２ＦｅＯ－ＳｉＯ２）が存在する箇所の強度が高すぎ、伸びが低かった。表１では、比較例２において、Ｃｒ－０．５（Ｓｉ＋Ａｌ）が０．２％≦Ｃｒ－０．５（Ｓｉ＋Ａｌ）≦０．４２％の要件を満たしておらず、実施例１に比べると、両者は同じプロセスを適用したが、比較例２のほうは、ベイナイト組織の変態に不利であり、組織中に多角形フェライトとパーライトが多量に存在し、強度の向上及び穴拡げ率の向上に不利であった。表１では、比較例３と実施例２を比較すると分かるように、比較例３のＴｉ含有量が低く、０．０８％≦３．３Ｎｂ＋Ｔｉ≦０．２０％を満たしておらず、両者は同じプロセスを適用したが、比較例３のほうは、結晶粒微細化作用が小さく、且つ析出強化作用も弱く、引張強度が７８０ＭＰａ以上に到達できなかった。 As can be seen from Table 1, in Comparative Example 1, Cr-0.5(Si+Al) does not satisfy the requirement of 0.2%≦Cr-0.5(Si+Al)≦0.42%. , compared to Example 1, the same process was applied to both, but Comparative Example 1 had a higher Si content, and ferro-olivine (2FeO-SiO 2 ) oxide scale was easily formed and difficult to remove. It is difficult to obtain steel strip with a high level of surface, and it is difficult to control the red scale on the surface, which makes it difficult to accurately measure the hot rolling temperature measurement process, and the instability of the product. The strength was too high and the elongation was low in the areas where iron olivine (2FeO-SiO 2 ) was present, which was related to performance. In Table 1, in Comparative Example 2, Cr-0.5(Si+Al) does not satisfy the requirement of 0.2%≦Cr-0.5(Si+Al)≦0.42%, and compared to Example 1, The same process was applied to both cases, but Comparative Example 2 was disadvantageous to the transformation of the bainite structure, and a large amount of polygonal ferrite and pearlite existed in the structure, resulting in an improvement in strength and hole expansion rate. It was a disadvantage. In Table 1, as can be seen by comparing Comparative Example 3 and Example 2, the Ti content of Comparative Example 3 is low and does not satisfy 0.08%≦3.3Nb+Ti≦0.20%, and both are the same. Although the process was applied, in Comparative Example 3, the grain refining effect was small, and the precipitation strengthening effect was also weak, and the tensile strength could not reach 780 MPa or more.

また、表２と併せて見れば分かるように、比較例４において、加熱温度が比較的に低く、ＴｉとＮｂの固溶に不利であり、後段の冷却と巻取り過程においてＮｂとＴｉの微細な炭化物の析出に不利であり、強度の向上に不利であった。比較例５において、低い巻取り温度が適用されたが、過冷却組織にある程度のマルテンサイトが存在するようになり、伸びと穴拡げ率の向上に不利であった。比較例６において、大きな平坦化量が適用されたが、実施例１に比べて、伸びが３．４％損失した。 In addition, as can be seen from Table 2, in Comparative Example 4, the heating temperature was relatively low, which was disadvantageous for solid solution of Ti and Nb, and fine particles of Nb and Ti were formed in the subsequent cooling and winding process. This was disadvantageous for the precipitation of carbides and was disadvantageous for improving strength. In Comparative Example 5, a low winding temperature was applied, but a certain amount of martensite came to exist in the supercooled structure, which was disadvantageous to improving elongation and hole expansion rate. In Comparative Example 6, a large amount of flattening was applied, but compared to Example 1, there was a 3.4% loss in elongation.

熱間圧延された表面状態の相違が力学的特性の均一性に及ぼす影響を比較するために、実施例４の組成とプロセスを用いて、異なる脱リン圧力を設定したことで異なる表面状態の帯鋼を獲得したが、表面処理効果が悪いほど、その表面粗さが大きくなり、強度も相応に高くなり、伸びが低くなった。 In order to compare the effects of different hot-rolled surface conditions on the uniformity of mechanical properties, the composition and process of Example 4 were used to create bands with different surface conditions by setting different dephosphorization pressures. Although the steel was obtained, the worse the surface treatment effect, the larger its surface roughness, the higher the strength, and the lower the elongation.

表面状態の相違が力学的特性に及ぼす影響は表４に示す。また、図３と図４はそれぞれ、異なる表面状態のプロファイルを示す。ただし、図３は、表面が良好な帯鋼の表面酸化スケールの表面プロファイルを示し、図４は、表面が「ＮＧ１」の帯鋼の表面酸化スケールの表面プロファイルを示す。 Table 4 shows the effects of different surface conditions on mechanical properties. Moreover, FIGS. 3 and 4 each show profiles of different surface states. However, FIG. 3 shows the surface profile of the surface oxidation scale of the steel strip with a good surface, and FIG. 4 shows the surface profile of the surface oxidation scale of the steel strip with the "NG1" surface.

図１は、実施例１にかかる高穴拡げ性複相鋼の金属ミクロ組織図である。
図２は、実施例１にかかる高穴拡げ性複相鋼のＳＥＭミクロ組織図である。 FIG. 1 is a metal microstructure diagram of the highly expandable multiphase steel according to Example 1.
FIG. 2 is an SEM microstructure diagram of the high hole expandability dual-phase steel according to Example 1.

図１と図２を併せて見れば分かるように、本願にかかる高穴拡げ性複相鋼の微細組織はフェライト＋ベイナイトであり、微細組織には、（Ｔｉ，Ｎｂ）Ｃ及びＮｂＮを含む微量合金析出物があった。 As can be seen from FIGS. 1 and 2 together, the microstructure of the high hole expandability dual-phase steel according to the present application is ferrite + bainite, and the microstructure contains trace amounts of (Ti, Nb)C and NbN. There were alloy precipitates.

図５は、実施例３にかかる高穴拡げ性複相鋼の、異なる平坦化変形量での力学的特性の変化を示す。 FIG. 5 shows changes in mechanical properties of the high hole expandability multiphase steel according to Example 3 at different amounts of flattening deformation.

図５に示すように、平坦化量の増加に従い、強度は向上する傾向にあった。
以上から分かるように、本発明にかかる高穴拡げ性複相鋼は、良好な穴拡げ性と良好な可塑性を両立させることができ、且つ本願にかかる高穴拡げ性複相鋼の２相はフェライトとベイナイトであるので、従来の材料である低合金高強度鋼やフェライト・マルテンサイト二相鋼に比べて硬度差が小さいことにより、その穴拡げ性と冷間成形性が良好となる。また、本発明にかかる製造方法も同じく、上記の利点及び有益な効果を有する。 As shown in FIG. 5, the strength tended to improve as the amount of flattening increased.
As can be seen from the above, the high hole expandability multiphase steel according to the present invention can achieve both good hole expandability and good plasticity, and the two phases of the high hole expandability multiphase steel according to the present invention are Since it is made of ferrite and bainite, the difference in hardness is smaller than that of conventional materials such as low-alloy high-strength steel and ferrite-martensitic dual-phase steel, resulting in good hole expandability and cold formability. Moreover, the manufacturing method according to the present invention also has the above-mentioned advantages and beneficial effects.

本発明の保護の範囲における従来技術部分は、本出願書類に記載の実施例に限定されるものではなく、本発明の方案と矛盾しない先行技術（先行の特許文献、先行の公開出版物、先行の公開使用などを含むが、それらに限定されない）は、全て本発明の保護の範囲に取り入れられることを説明すべきである。 The prior art within the scope of protection of the present invention is not limited to the embodiments described in the present application, but includes prior art that does not contradict the scheme of the present invention (earlier patent documents, earlier published publications, prior art). (including, but not limited to, public use, etc.) are all included within the scope of protection of the present invention.

また、本願における各技術特徴の組み合わせは、本願の特許請求の範囲に記載の組み合わせ、若しくは具体的な実施例に記載の組み合わせに限定されるものではなく、互いに矛盾していない限り、本願の記載の技術特徴は全て任意の形態で自由に組み合わせる若しくは結合することができる。 Furthermore, the combinations of technical features in this application are not limited to the combinations described in the claims of this application or the combinations described in specific examples, and unless they are inconsistent with each other, All technical features of can be freely combined or combined in any form.

本発明は上記の実施例に限定されるものではなく、当業者が本発明の開示内容から直接的に導き出すことができる、又は容易に想到することができる類似の変化若しくは変形はいずれも、本発明の保護範囲に含まれることは、明らかである。
The present invention is not limited to the embodiments described above, and any similar changes or modifications that can be directly derived or easily conceived by a person skilled in the art from the disclosure of the present invention are applicable to the present invention. It is clear that the invention falls within the scope of protection of the invention.

Claims (7)

微細組織がフェライト＋ベイナイトであり、以下の化学元素質量百分率を有することを特徴とする、高穴拡げ性複相鋼。
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％、残部はＦｅ及び他の不可避不純物であって、
前記複相鋼の幅方向引張強度が≧７８０ＭＰａで、降伏強度が≧７００ＭＰａで、伸びＡ５０が≧１５％で、抜き穴の穴拡げ率が≧５０％であり、
ＩＳＯ／ＤＩＳ１６６３０規格に準拠した穴広げ率計測方法に従い、試験片サンプルのサイズを１５０×１５０ｍｍにし、抜き穴のサイズをΦ１０ｍｍにし、クリアランスを１２．５％にし、６０°の円錐パンチを用いてせん断面から穴を広げ、き裂が板厚を貫通した時点の内径ｄを求め、穴拡げ前の内径をｄ ０ とすると、下式から限界穴拡げ値λ％を求めた。限界穴拡げ値λ％＝（ｄ－ｄ ０ ）／ｄ ０ ×１００％。 A multiphase steel with high hole expandability, which has a microstructure of ferrite + bainite and has the following chemical element mass percentages:
C: 0.06-0.09%, Si: 0.05-0.5%, Al: 0.02-0.1%, Mn: 1.5-1.8%, Cr: 0.3-0. 0.6%, Nb≦0.03%, Ti: 0.05-0.12%, the remainder is Fe and other unavoidable impurities ,
The multi-phase steel has a tensile strength in the width direction of ≧780 MPa, a yield strength of ≧700 MPa, an elongation A50 of ≧15%, and a hole expansion rate of the punched hole of ≧50%,
According to the hole expansion rate measurement method based on the ISO/DIS16630 standard, the test piece sample size was 150 x 150 mm, the hole size was Φ10 mm, the clearance was 12.5%, and a 60° conical punch was used. The hole was enlarged from the cross section, the inner diameter d at the time when the crack penetrated through the plate thickness was determined, and the inner diameter before the hole was enlarged was set as d0, and the critical hole enlargement value λ% was determined from the following formula. Limit hole expansion value λ% = (d-d 0 )/d 0 ×100%. Ｎｂ元素の含有量は０．０１５～０．０３％であることを特徴とする、請求項１に記載の高穴拡げ性複相鋼。 The high hole expandability dual-phase steel according to claim 1, characterized in that the content of Nb element is 0.015 to 0.03%. 他の不可避不純物では、Ｐ≦０．０３％、Ｓ≦０．０２％、Ｎ≦０．００５％であることを特徴とする、請求項１に記載の高穴拡げ性複相鋼。 The high hole expandability dual-phase steel according to claim 1, characterized in that other unavoidable impurities satisfy P≦0.03%, S≦0.02%, and N≦0.005%. その化学元素質量百分率含有量は、下記の各式の少なくとも一つを満たすことを特徴とする、請求項１に記載の高穴拡げ性複相鋼。
０．２％≦Ｃｒ－０．５（Ｓｉ＋Ａｌ）≦０．４２％；
０．０８％≦３．３Ｎｂ＋Ｔｉ≦０．２０％。 The high hole expandability dual-phase steel according to claim 1, wherein the chemical element mass percentage content satisfies at least one of the following formulas.
0.2%≦Cr-0.5(Si+Al)≦0.42%;
0.08%≦3.3Nb+Ti≦0.20%. その微細組織には、（Ｔｉ，Ｎｂ）Ｃ及びＮｂＮを含む微量合金析出物があることを特徴とする、請求項１に記載の高穴拡げ性複相鋼。 2. Highly expandable dual-phase steel according to claim 1, characterized in that its microstructure contains trace alloy precipitates containing (Ti, Nb)C and NbN. 前記幅方向引張強度が≧８００ＭＰａで、前記降伏強度が≧７３０ＭＰａで、前記伸びＡ５０が≧１５％で、前記抜き穴の穴拡げ率が≧７０％であることを特徴とする、請求項１に記載の高穴拡げ性複相鋼。 Claim 1, wherein the tensile strength in the width direction is ≧800 MPa, the yield strength is ≧730 MPa, the elongation A50 is ≧15%, and the hole expansion rate of the punched hole is ≧70%. A multi-phase steel with high hole expandability described in . 以下の工程を含むことを特徴とする、請求項１～６のいずれかに記載の高穴拡げ性複相鋼の製造方法。
（１）製錬・鋳造；
（２）加熱；加熱温度を１２００～１２６０℃にする；
（３）熱間圧延：総圧下率を≧８０％に制御し、粗圧延が再結晶領域で行われるように制御し、粗圧延出口温度を１０２０～１１００℃に制御する；仕上圧延過程に準定速圧延プロセスを適用し、仕上圧延速度を６～１２ｍ／ｓに制御し、鋼材圧延加速度を≦０．００５ｍ／ｓ２に制御する；仕上圧延温度を８４０～９００℃に制御する；
（４）脱リン；脱リン圧力を１５～３５ＭＰａに制御する；
（５）層流冷却：緩和時間を０～８ｓに制御し、層流冷却速度を４０～７０℃／ｓに制御する；
（６）巻取り；巻取り温度を４８０～５６０℃にする；
（７）平坦化；平坦化圧延力を１００～８００トンに制御し、且つ平坦化伸びが≦１．５％を満たす；
（８）酸洗。 The method for producing a high hole expandability dual-phase steel according to any one of claims 1 to 6 , which comprises the following steps.
(1) Smelting and casting;
(2) Heating; heating temperature to 1200-1260°C;
(3) Hot rolling: Control the total rolling reduction to ≧80%, control the rough rolling to occur in the recrystallization region, and control the rough rolling outlet temperature to 1020-1100°C; similar to the finish rolling process. Apply a constant speed rolling process, control the finishing rolling speed to 6~12m/s, and control the steel rolling acceleration to ≦0.005m/ s2 ; control the finishing rolling temperature to 840~900°C;
(4) Dephosphorization: Control the dephosphorization pressure to 15 to 35 MPa;
(5) Laminar cooling: control the relaxation time to 0 to 8 s, and control the laminar cooling rate to 40 to 70°C/s;
(6) Winding; set the winding temperature to 480-560°C;
(7) Flattening; flattening rolling force is controlled to 100 to 800 tons, and flattening elongation satisfies ≦1.5%;
(8) Pickling.
JP2022519055A 2019-09-27 2020-09-25 High hole expandability multi-phase steel and its manufacturing method Active JP7375179B2 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
CN201910920750.3A CN112575267A (en) 2019-09-27 2019-09-27 High-hole-expansion complex phase steel and manufacturing method thereof
CN201910920750.3 2019-09-27
PCT/CN2020/117724 WO2021057899A1 (en) 2019-09-27 2020-09-25 Complex-phase steel having high hole expansibility and manufacturing method therefor

Publications (2)

Publication Number Publication Date
JP2022550329A JP2022550329A (en) 2022-12-01
JP7375179B2 true JP7375179B2 (en) 2023-11-07

Family

ID=75109614

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2022519055A Active JP7375179B2 (en) 2019-09-27 2020-09-25 High hole expandability multi-phase steel and its manufacturing method

Country Status (6)

Country Link
US (1) US20220341010A1 (en)
EP (1) EP4036267A4 (en)
JP (1) JP7375179B2 (en)
KR (1) KR20220073762A (en)
CN (1) CN112575267A (en)
WO (1) WO2021057899A1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117344203A (en) * 2022-06-27 2024-01-05 宝山钢铁股份有限公司 800 Mpa-grade hot-rolled complex-phase steel with tensile strength and manufacturing method thereof
CN116083795A (en) * 2022-12-23 2023-05-09 本钢板材股份有限公司 Hot-rolled high-reaming steel with high R value and production method thereof

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009263685A (en) 2008-04-22 2009-11-12 Nippon Steel Corp High strength steel sheet having reduced deterioration in characteristic after cutting, and method for producing the same
CN103602895A (en) 2013-11-29 2014-02-26 宝山钢铁股份有限公司 High-hole-expansion-ratio steel plate with tensile strength of 780 MPa and manufacturing process thereof
JP2014514443A (en) 2011-03-24 2014-06-19 アルセロルミタル・インベステイガシオン・イ・デサロジヨ・エセ・エレ Hot rolled steel sheet and related manufacturing method
CN104513930A (en) 2014-12-19 2015-04-15 宝山钢铁股份有限公司 Ultrahigh-strength hot-rolled complex phase steel plate and steel strip with good bending and broaching performance and manufacturing method thereof
JP2015199987A (en) 2014-04-08 2015-11-12 新日鐵住金株式会社 HIGH STRENGTH HOT ROLLED STEEL SHEET EXCELLENT IN LOW TEMPERATURE TOUGHNESS AND UNIFORM ELONGATION AND HOLE EXPANSIBILITY AND HAVING TENSILE STRENGTH OF 780 MPa OR MORE AND PRODUCTION METHOD THEREFOR
CN105483545A (en) 2014-09-19 2016-04-13 鞍钢股份有限公司 800MPa level hot-rolling high broaching steel plate and manufacturing method thereof
CN108570604A (en) 2018-04-28 2018-09-25 唐山钢铁集团有限责任公司 A kind of high reaming steel band of 780MPa grades of hot rolling acid-cleaning and its production method

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101285156B (en) * 2008-06-05 2010-06-23 广州珠江钢铁有限责任公司 700MPa grade composite strengthening bainite steel and method for preparing same
EP2489748B1 (en) * 2011-02-18 2017-12-13 ThyssenKrupp Steel Europe AG Hot-rolled steel surface product produced from a complex phase steel and method for the manufacture
KR20130110638A (en) * 2012-03-29 2013-10-10 현대제철 주식회사 Steel sheet and method of manufacturing the same
JP6287623B2 (en) * 2013-06-25 2018-03-07 新日鐵住金株式会社 High-strength hot-rolled steel sheet and its manufacturing method
CN105849295B (en) * 2013-12-26 2019-02-19 Posco公司 Weldability and the excellent hot rolled steel plate and preparation method thereof of deburring
JP6515386B2 (en) * 2015-07-28 2019-05-22 日本製鉄株式会社 Hot rolled steel sheet and method of manufacturing the same
CN105821301A (en) * 2016-04-21 2016-08-03 河北钢铁股份有限公司邯郸分公司 800MPa-level hot-rolled high strength chambering steel and production method thereof
CN106521327B (en) * 2016-12-27 2018-08-21 首钢集团有限公司 A kind of hot rolling acid-cleaning strip and its production method with high reaming performance
CN110291215B (en) * 2017-01-20 2022-03-29 蒂森克虏伯钢铁欧洲股份公司 Hot-rolled flat steel product consisting of a complex phase steel with a predominantly bainitic structure and method for producing such a flat steel product
CN109594020B (en) * 2018-12-28 2020-07-24 首钢集团有限公司 Cold-rolled complex phase steel with tensile strength of 1000MPa and preparation method thereof

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009263685A (en) 2008-04-22 2009-11-12 Nippon Steel Corp High strength steel sheet having reduced deterioration in characteristic after cutting, and method for producing the same
JP2014514443A (en) 2011-03-24 2014-06-19 アルセロルミタル・インベステイガシオン・イ・デサロジヨ・エセ・エレ Hot rolled steel sheet and related manufacturing method
CN103602895A (en) 2013-11-29 2014-02-26 宝山钢铁股份有限公司 High-hole-expansion-ratio steel plate with tensile strength of 780 MPa and manufacturing process thereof
JP2015199987A (en) 2014-04-08 2015-11-12 新日鐵住金株式会社 HIGH STRENGTH HOT ROLLED STEEL SHEET EXCELLENT IN LOW TEMPERATURE TOUGHNESS AND UNIFORM ELONGATION AND HOLE EXPANSIBILITY AND HAVING TENSILE STRENGTH OF 780 MPa OR MORE AND PRODUCTION METHOD THEREFOR
CN105483545A (en) 2014-09-19 2016-04-13 鞍钢股份有限公司 800MPa level hot-rolling high broaching steel plate and manufacturing method thereof
CN104513930A (en) 2014-12-19 2015-04-15 宝山钢铁股份有限公司 Ultrahigh-strength hot-rolled complex phase steel plate and steel strip with good bending and broaching performance and manufacturing method thereof
CN108570604A (en) 2018-04-28 2018-09-25 唐山钢铁集团有限责任公司 A kind of high reaming steel band of 780MPa grades of hot rolling acid-cleaning and its production method

Also Published As

Publication number Publication date
EP4036267A1 (en) 2022-08-03
EP4036267A4 (en) 2023-06-07
US20220341010A1 (en) 2022-10-27
JP2022550329A (en) 2022-12-01
WO2021057899A1 (en) 2021-04-01
KR20220073762A (en) 2022-06-03
CN112575267A (en) 2021-03-30

Similar Documents

Publication Publication Date Title
CN101263239B (en) Method of producing high-strength steel plates with excellent ductility and plates thus produced
CN107119228B (en) A kind of 700~800MPa of tensile strength grades of hot rolling high-strength light dual phase steels and its manufacturing method
RU2627068C2 (en) HIGH-STRENGTH MULTI-PHASE STEEL AND METHOD FOR STRIP MANUFACTURE FROM THIS STEEL WITH MINIMUM TENSILE STRENGTH AT 580 MPa
WO2018122679A1 (en) Tempered and coated steel sheet having excellent formability and a method of manufacturing the same
US20140230970A1 (en) Hot-rolled steel sheet and associated production method
WO2018116099A1 (en) Tempered and coated steel sheet having excellent formability and a method of manufacturing the same
CN113388779B (en) 1.5 GPa-grade ultrahigh-strength high-plasticity high-hole-expansion DH steel plate and preparation method thereof
JP7244723B2 (en) High-strength steel material with excellent durability and its manufacturing method
JP4644075B2 (en) High-strength steel sheet with excellent hole expansibility and manufacturing method thereof
CN107326276B (en) A kind of 500~600MPa of tensile strength grades of hot rolling high-strength light dual phase steels and its manufacturing method
CN110551939A (en) Hot-dip galvanized steel plate with yield strength of 320MPa and production method thereof
JP7375179B2 (en) High hole expandability multi-phase steel and its manufacturing method
US20040118489A1 (en) Dual phase hot rolled steel sheet having excellent formability and stretch flangeability
JPH083679A (en) Hot rolled high strength steel plate excellent in formability and fatigue characteristic and having thermal softening resistance and its production
CN110621794B (en) High-strength steel sheet having excellent ductility and stretch flangeability
JP7439265B2 (en) Low silicon low carbon equivalent gigapascal grade multiphase steel plate/strip and manufacturing method thereof
JP2023507528A (en) LOW-CARBON LOW-COST ULTRA-HIGH-STRENGTH MULTI-PHASE STEEL STEEL/STRIP AND METHOD FOR MANUFACTURING SAME
CN111363901B (en) Ferrite-martensite hot-rolled dual-phase steel with high surface quality and manufacturing method thereof
JP2007119842A (en) Method for producing high-strength galvanized steel sheet excellent in stretch-flanging property
JP4452191B2 (en) Manufacturing method of high-stretch flange-formable hot-rolled steel sheet with excellent material uniformity
JP2002363685A (en) Low yield ratio high strength cold rolled steel sheet
JP3954411B2 (en) Manufacturing method of high-strength hot-rolled steel sheet with excellent material uniformity and hole expandability
CN107829025B (en) thin-gauge dual-phase steel with good hole expanding performance and processing method thereof
JP4428075B2 (en) High-strength hot-dip galvanized steel sheet excellent in stretch flangeability and method for producing the same
JPH04276024A (en) Manufacture of high strength hot rolled steel sheet excellent in stretch-flanging property

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20220324

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20230419

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20230509

A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20230807

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20230926

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20231025

R150 Certificate of patent or registration of utility model

Ref document number: 7375179

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R150