US20180363084A1 - Ultra high-strength steel sheet having excellent hole expandability and manufacturing method therefor - Google Patents

Ultra high-strength steel sheet having excellent hole expandability and manufacturing method therefor Download PDF

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Publication number
US20180363084A1
US20180363084A1 US16/060,242 US201616060242A US2018363084A1 US 20180363084 A1 US20180363084 A1 US 20180363084A1 US 201616060242 A US201616060242 A US 201616060242A US 2018363084 A1 US2018363084 A1 US 2018363084A1
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Prior art keywords
steel sheet
less
ultra high
temperature
strength
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US16/060,242
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Sea-Woong LEE
Kyoo-Young Lee
Joo-Hyun RYU
Won-Hwi LEE
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Posco Holdings Inc
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Posco Co Ltd
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Assigned to POSCO reassignment POSCO ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: LEE, KYOO-YOUNG, LEE, Won-Hwi, RYU, JOO-HYUN, LEE, Sea-Woong
Publication of US20180363084A1 publication Critical patent/US20180363084A1/en
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    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/01—Layered products comprising a layer of metal all layers being exclusively metallic
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/01—Layered products comprising a layer of metal all layers being exclusively metallic
    • B32B15/013—Layered products comprising a layer of metal all layers being exclusively metallic one layer being formed of an iron alloy or steel, another layer being formed of a metal other than iron or aluminium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B15/043—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of metal
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/18—Layered products comprising a layer of metal comprising iron or steel
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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
    • C—CHEMISTRY; METALLURGY
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    • 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
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    • C—CHEMISTRY; METALLURGY
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    • C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
    • C—CHEMISTRY; METALLURGY
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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    • 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
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
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    • C23C2/022—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by heating
    • C23C2/0224—Two or more thermal pretreatments
    • C—CHEMISTRY; METALLURGY
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    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
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    • C23C2/06—Zinc or cadmium or alloys based thereon
    • 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
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    • C23C2/36—Elongated material
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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    • Y10T428/12979—Containing more than 10% nonferrous elements [e.g., high alloy, stainless]

Definitions

  • the present invention relates to an ultra high-strength steel sheet having excellent hole expandability and a manufacturing method therefor.
  • a quenching & partitioning (Q & P) method capable of securing low temperature martensite by quenching hot austenite at a temperature between a martensitic transformation start temperature M s and a martensitic transformation finish temperature M f in a heat treatment process and at the same time, securing strength and elongation by diffusing austenite stabilizing elements such as C, Mn and the like into a remainder of austenite at an appropriate temperature.
  • a heat treatment process of heating steel to a temperature of A 3 or more and quenching the steel to a temperature below the temperature M s to thereby maintain the steel to a temperature between M s and M f is referred to as a 1 step Q & P
  • another treatment process of reheating the steel to a temperature of M s or more after the quenching to thereby perform heat treatment is referred to as a 2 step Q & P.
  • Patent Document 1 describes a method of retaining austenite using a Q & P heat treatment, but simply explains the concept the Q & P heat treatment, such that practical applications of the method are restrictive.
  • Patent Document 1 US Patent Publication No. 2006-0011274
  • An aspect of the present invention is to provide an ultra high-strength steel sheet capable of cold press forming and having excellent hole expandability, and a manufacturing method therefor.
  • an ultra high-strength steel sheet having excellent hole expandability comprising: 0.15 to 0.30% of C, 1.0 to 3.0% of Si, 3.0 to 5.0% of Mn, 0.020% or less of P, 0.010% or less of S, 0.01 to 3.0% of Al, and 0.020% or less of N (excluding 0%) by weight, with a remainder of Fe and other inevitable impurities, wherein a microstructure contains 5% to 20% by area fraction of retained austenite with a remainder including ferrite, bainite and fresh martensite.
  • a method of manufacturing an ultra high-strength steel sheet having excellent hole expandability comprising: heating a steel slab including: 0.15 to 0.30% of C, 1.0 to 3.0% of Si, 3.0 to 5.0% of Mn, 0.020% or less of P, 0.010% or less of S, 0.01 to 3.0% of Al, and 0.020% or less of N (excluding 0%) by weight, with a remainder of Fe and other inevitable impurities, to 1000 to 1250° C.; hot-rolling the heated steel slab such that a temperature at a finish-rolled outlet side thereof is 500 to 950° C. to obtain a hot-rolled steel sheet; winding the hot-rolled steel sheet at a temperature of 750° C.
  • an ultra high-strength steel sheet having excellent hole expandability, and a manufacturing method therefor may be provided. More specifically, it exhibits excellent yield strength and hole expandability and can be suitably applied to cold press forming, and it is possible to secure a high yield strength and tensile strength after molding, allowing for replacing of hot press formed parts. Accordingly, it is feasible to replace expensive hot press formed parts with low cost cold press formed parts and to suppress CO 2 generation caused by high temperature molding. Thus, as an eco-friendly material, it contributes to preservation of global environment.
  • FIG. 1 is a time-temperature graph for 1 step Q & P and 2 step Q & P.
  • FIG. 2 is a graph illustrating the value of ⁇ ln(1-f) according to the temperature of sample No. 9
  • the present inventors have intensively researched the development of steel sheets for cold press forming, capable of replacing conventional hot press-formed steel, thereby having mechanical properties equal to or greater than those of conventional hot press formed steel and allowing for a reduction in manufacturing cost of components.
  • the inventors have found that it is possible to provide a steel sheet having physical properties and a microstructure suitable for cold press forming, and have completed the present invention.
  • An ultra high-strength steel sheet having excellent hole expandability comprises: 0.15 to 0.30% of C, 1.0 to 3.0% of Si, 3.0 to 5.0% of Mn, 0.020% or less of P, 0.010% or less of S, 0.01 to 3.0% of Al, and 0.020% or less of N (excluding 0%) by weight, with a remainder of Fe and other inevitable impurities, wherein a microstructure contains 5% to 20% by area fraction of retained austenite with the remainder including ferrite, bainite and fresh martensite.
  • Carbon (C) is an element contributing to stabilization of the retained austenite.
  • the content of C is less than 0.15%, it is difficult to sufficiently secure stability of the austenite during a final heat treatment.
  • the content of C exceeds 0.30%, there are limitations that that not only the risk of occurrence of defects in a cast piece increases, but also weldability is greatly deteriorated. Therefore, the content of C is preferably, 0.15 to 0.30%.
  • Si is an element that inhibits carbide precipitation and contributes to stabilization of retained austenite. In order to obtain the above-mentioned effect, it is preferable to add Si by the amount of 0.1% or more. On the other hand, when the content of Si exceeds 3.0%, a ferrite phase exists even at a high temperature of 900° C. or more and accordingly, there are limitations that that an austenite single phase cannot be secured at a high temperature. Therefore, the content of Si is preferably, 0.1% to 3.0%.
  • Mn is an element contributing to formation and stabilization of retained austenite.
  • Mn is known to be an element widely used in transformation induced plasticity steels.
  • Mn is usually added in the amount of 3.0% for TRIP steels and in the amount of 18.0% or more for austenite single phase steels, TWIP steels. This is because that when the amount of Mn is contained in an intermediate range, a large amount of martensite is produced, thereby lowering elongation.
  • the content of Mn is less than 3.0%, it is difficult to secure retained austenite at room temperature after heat treatment, and a large amount of phases such as ferrite and bainite may be contained during quenching after annealing.
  • the content of Mn exceeds 5.0%, there are limitations in that production costs are increased and a rolling load is increased during hot-rolling, thereby leading to degradations in workability. Therefore, the content of Mn is preferably 3.0 to 5.0%.
  • the content of P is preferably 0.020% or less.
  • S is an impurity element, and when the content thereof exceeds 0.010%, ductility and weldability of a steel sheet are likely to be deteriorated. Therefore, the content of S is preferably 0.010% or less.
  • Al is an element combined with oxygen to perform deoxidizing, and it is preferable to maintain the content of Al to 0.010% or more in order to obtain stable deoxidizing effects.
  • Al is a representative ferrite region expansion element at high temperature, together with Si.
  • the content of Al exceeds 3.0%, a ferrite phase co-exists with an austenite phase even at a high temperature of 900° C. or more, so that an austenite single phase region which is important during a heat treatment process may be absent. Therefore, the content of Al is preferably 0.01 to 3.0%.
  • N 0.020% or less (excluding 0%)
  • N is an effective component for stabilizing austenite, but when it exceeds 0.020%, the risk of brittleness increases greatly, so the content is limited to 0.020% or less.
  • the lower limit thereof is not particularly limited, but may inevitably be included in a manufacturing process.
  • the remaining element of the present invention is iron (Fe).
  • impurities that are not intended may be inevitably incorporated from raw materials or the surrounding environment, so that they cannot be excluded. These impurities are not specifically mentioned in this specification, as they are known to any person skilled in the art of manufacturing.
  • the steel sheet may further include at least one of 1.5% or less of Cr (excluding 0%), 0.005 to 0.3% of Ti, 0.005 to 0.3% of Nb, and 0.005 to 0.3% of V and 0.05 to 0.3% of Mo, by weight.
  • Cr is known as an element capable of suppressing the growth of ferrite and enhancing hardenability of a material.
  • the content of Cr is preferably 1.5% or less (excluding 0%).
  • the Ti, Nb and V are effective elements for an increase in strength and grain size miniaturization of a steel sheet.
  • the content of each of Ti, Nb and V is less than 0.005%, it may be difficult to sufficiently secure such effects.
  • the content of each of Ti, Nb and V exceeds 0.30%, production costs can be increased and ductility can be greatly lowered due to excessive precipitates. Therefore, the content of each of Ti, Nb and V is preferably 0.005 to 0.30%.
  • the Mo is an element that enhances hardenability and suppresses ferrite formation, inhibits the formation of ferrite upon cooling after annealing. It is also an element contributing to an increase in strength through the formation of fine carbides.
  • the content of Mo is less than 0.05%, it is difficult to sufficiently secure such effects.
  • the content of Mo exceeds 0.3%, ferroalloy costs increase due to an excess amount of alloy. Therefore, the content of Mo is preferably 0.05 to 0.3%.
  • the microstructure of the steel sheet contains 5% to 20% by area fraction of retained austenite with the remainder including ferrite, bainite and fresh martensite.
  • the martensite phase In order to increase the strength of the steel sheet, it is important to have a martensite phase having a high dislocation density. However, due to the high dislocation density, the martensite phase exhibits limited elongation. Accordingly, by retaining austenite of 5% or more by area, it is possible to secure elongation by increasing work hardening through the formation of transformed martensite during transformation. However, when the retained austenite exceeds 20% by area, the stability of the austenite is reduced, and a yield ratio (YR) becomes 0.7 or less. Therefore, it is preferable that the area percentage is 20% or less.
  • the steel sheet may have transformed martensite of 15% or less by area in the tensile test.
  • the steel sheet according to an aspect of the present invention has a yield strength of 850 MPa or more, a tensile strength of 1200 MPa or more, a hole expandability of 15% or more, and a yield ratio of 0.7 or more.
  • the steel sheet may have a hot-dip galvanized layer formed on a surface of the steel sheet.
  • the method of manufacturing an ultra high-strength steel sheet having excellent hole expandability may include: heating a steel slab satisfying the alloy composition described above to 1000 to 1250° C.; hot-rolling the heated steel slab such that a temperature at a finish-rolled outlet side thereof is 500 to 950° C. to obtain a hot-rolled steel sheet; winding the hot-rolled steel sheet at a temperature of 750° C. or less; cold-rolling the wound hot-rolled steel sheet at a reduction ratio of 30% to 80% to obtain a cold-rolled steel sheet; annealing the cold-rolled steel sheet in a temperature range of 750° C.
  • the steel slab satisfying the above alloy composition is heated to 1000 to 1250° C.
  • the heating temperature of the steel slab is less than 1000° C., there is a defect in which a rolling load sharply increases.
  • the heating temperature exceeds 1250° C. energy costs increase and the amount of surface scaling increases greatly.
  • the heated steel slab is hot-rolled such that a temperature on a finish-rolled outlet side thereof is 500 to 950° C. to obtain a hot-rolled steel sheet, and the hot-rolled steel sheet is wound at a temperature of 750° C. or less.
  • the wound hot-rolled steel sheet is cooling-rolled at a reduction ratio of 30% to 80% to obtain a cold-rolled steel sheet, and then, the cold-rolled steel sheet is annealed in a temperature range of 750° C. to 950° C.
  • the cold-rolling reduction rate is less than 30%, accumulation energy for recrystallization during subsequent annealing may be insufficient, so that recrystallization may not occur.
  • the cold-rolling reduction rate exceeds 80%, rolling workability is significantly unstable and power costs greatly increase. Thus, it is preferable to perform cold-rolling at a reduction ratio of 30% to 80%.
  • the annealing temperature is preferably, 750° C. to 950° C.
  • the cooled cold-rolled steel sheet is heat-treated at Ms+100° C. or more for 350 seconds or more.
  • a heat treatment temperature needs to be Ms+100° C. or more is to ensure that the diffusion of austenite stabilizing elements such as C, Mn and the like is smoothly performed and the stability of retained austenite is secured, thereby allowing for the obtainment of elongation and hole expandability.
  • the upper limit of the heat treatment temperature is not particularly limited, when the temperature is higher than 500° C., carbides can be easily precipitated and the austenite stability cannot be ensured, such that the upper limit of the heat treatment temperature may be 500° C.
  • the temperature of Ms can be obtained by using the following relational expression (1).
  • each element symbol represents the content of each element as weight %, and the unit of Ms is ° C. In a case in which the corresponding element was not contained, the content was calculated as 0).
  • the temperature of Ms is a very important condition among manufacturing conditions of the present invention.
  • a conventional Temperature of Ms is applied as it is, there is a large error, so that the relational expression 1 according to the composition of the present invention is obtained.
  • a dilatometer test was performed using cold-rolled samples having the composition illustrated in Table 1, and the fraction of martensite formed during cooling was determined through this test method.
  • each sample was heated at 1000° C. and cooled and then, reheated to 1000° C., five times in total.
  • the Temperature of Ms could be obtained by plotting the fraction of martensite obtained through the dilatometer test using the following relational expression 2, and FIG. 2 is a graph illustrating a linear trend line applied to cold-rolled sample 9 .
  • f is a fraction (area %) of martensite generated during cooling and a is a constant related to the transformation driving force of martensite, and T is temperature (° C.).
  • the relational expression 1 can be conceived by optimizing constant values corresponding to respective elements.
  • the method further includes dipping the sample in a zinc plated bath after the heat treatment to form a hot-dip galvanized layer.
  • Steels having compositions illustrated in the following Table 2 were vacuum-melted with a 30 kg ingot, and then, maintained at a temperature of 1200° C. for 1 hour, followed by hot-rolling to complete finish-rolling at 900° C. and charging the finish-rolled steels into a preheated furnace at 600° C. to be maintained for 1 hour. Thereafter, the steels were furnace-cooled, and hot-rolled winding thereof was simulated. Next, the steels were cold-rolled at a reduction ratio of 50% and subsequently, annealed at 900 C, cooled to the cooling end temperature described in Table 3, and then subjected to a reheating treatment by keeping them at the heat treatment temperature described in Table 3 for 400 seconds.
  • the yield strength (YS), the tensile strength (TS), the elongation (TE), the retained austenite fraction and the yield ratio (YR) of the samples were measured and illustrated in Table 3 below.
  • Example 1 Further experiments were carried out by applying the same conditions as in Example 1 and the same heat treatment temperatures as in Table 4 below. Inventive Examples 1 to 3 and Comparative Example 2 are the same as those in Example 1 above.
  • the hole expandability is indicated by a ratio of the enlargement amount of a circular hole from at least one position thereof in a thickness direction of the hole at an edge of the hole when the circular hole is formed in a test piece and then expanded using a conical punch, to an initial hole size.
  • the hole expandability is known as an index for evaluating stretch flangeability and is expressed by the following relational expression 3.
  • ⁇ hole expandability (%)
  • Do is an initial hole diameter (10 mm in an embodiment of the present invention
  • Dh is a hole diameter after break (mm).
  • the definition of the clearance at the time of punching the initial hole is also necessary in order to evaluate the hole expandability, defined as a ratio of a distance between the die and the punch to a thickness of the test piece (defined according to Relational Expression 4). In the embodiment of the present invention, a clearance of 10% was used.
  • C clearance (%)
  • dd is an inner diameter of a punching die (mm)
  • t is a thickness of the test sample.

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11530459B2 (en) 2017-12-05 2022-12-20 Arcelormittal Cold rolled and annealed steel sheet and method of manufacturing the same
US11530461B2 (en) * 2017-12-05 2022-12-20 Arcelormittal Cold rolled and annealed steel sheet and method of manufacturing the same

Families Citing this family (4)

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Publication number Priority date Publication date Assignee Title
CA3093397C (fr) * 2018-03-30 2024-01-30 Ak Steel Properties, Inc. Acier a haute resistance de pointe de troisieme generation faiblement allie et procede pour la fabrication de celui-ci
CN112840055B (zh) * 2018-10-17 2022-07-22 杰富意钢铁株式会社 薄钢板及其制造方法
KR102231344B1 (ko) * 2019-05-17 2021-03-24 주식회사 포스코 구멍확장성 및 연성이 우수한 초고강도 강판 및 이의 제조방법
KR102321295B1 (ko) * 2019-12-18 2021-11-03 주식회사 포스코 가공성이 우수한 고강도 강판 및 그 제조방법

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014156140A1 (fr) * 2013-03-28 2014-10-02 Ｊｆｅスチール株式会社 Tôle d'acier à haute résistance galvanisée par immersion à chaud et son procédé de fabrication
US20140322559A1 (en) * 2011-05-18 2014-10-30 Thyssenkrupp Steel Europe Ag High-Strength Flat Steel Product and Method for Producing Same
US20190256940A1 (en) * 2016-11-07 2019-08-22 Posco Ultrahigh-strength steel sheet having excellent yield ratio, and manufacturing method therefor

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3307164B2 (ja) * 1995-06-09 2002-07-24 日本鋼管株式会社 耐水素遅れ割れ特性に優れた超高張力電縫鋼管の製造方法
JP3374659B2 (ja) * 1995-06-09 2003-02-10 日本鋼管株式会社 超高張力電縫鋼管およびその製造方法
JPH101740A (ja) * 1996-06-12 1998-01-06 Kobe Steel Ltd 耐遅れ破壊特性にすぐれる超高強度鋼板及びその製造方法
JP4608739B2 (ja) * 2000-06-14 2011-01-12 Ｊｆｅスチール株式会社 自動車ドア補強用鋼管の製造方法
AU2003270334A1 (en) 2002-09-04 2004-03-29 Colorado School Of Mines Method for producing steel with retained austenite
JP5412182B2 (ja) * 2009-05-29 2014-02-12 株式会社神戸製鋼所 耐水素脆化特性に優れた高強度鋼板
JP5825119B2 (ja) * 2011-04-25 2015-12-02 Ｊｆｅスチール株式会社 加工性と材質安定性に優れた高強度鋼板およびその製造方法
US9896751B2 (en) * 2011-07-29 2018-02-20 Nippon Steel & Sumitomo Metal Corporation High strength steel sheet and high strength galvanized steel sheet excellent in shapeability and methods of production of same
RU2581333C2 (ru) * 2012-01-13 2016-04-20 Ниппон Стил Энд Сумитомо Метал Корпорейшн Горячештампованная сталь и способ ее изготовления
TWI524953B (zh) * 2012-01-13 2016-03-11 新日鐵住金股份有限公司 冷軋鋼板及冷軋鋼板之製造方法
WO2014020640A1 (fr) * 2012-07-31 2014-02-06 Ｊｆｅスチール株式会社 Tôle d'acier galvanisée par immersion à chaud à résistance élevée qui présente une excellente aptitude au moulage et une excellente aptitude à la fixation de formes, ainsi que procédé de fabrication de cette dernière
WO2015115059A1 (fr) * 2014-01-29 2015-08-06 Ｊｆｅスチール株式会社 Tôle d'acier laminée à froid à haute résistance, et son procédé de fabrication
US10435762B2 (en) * 2014-03-31 2019-10-08 Jfe Steel Corporation High-yield-ratio high-strength cold-rolled steel sheet and method of producing the same

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140322559A1 (en) * 2011-05-18 2014-10-30 Thyssenkrupp Steel Europe Ag High-Strength Flat Steel Product and Method for Producing Same
WO2014156140A1 (fr) * 2013-03-28 2014-10-02 Ｊｆｅスチール株式会社 Tôle d'acier à haute résistance galvanisée par immersion à chaud et son procédé de fabrication
US20190256940A1 (en) * 2016-11-07 2019-08-22 Posco Ultrahigh-strength steel sheet having excellent yield ratio, and manufacturing method therefor

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11530459B2 (en) 2017-12-05 2022-12-20 Arcelormittal Cold rolled and annealed steel sheet and method of manufacturing the same
US11530461B2 (en) * 2017-12-05 2022-12-20 Arcelormittal Cold rolled and annealed steel sheet and method of manufacturing the same

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