EP4324954A2 - High-hardness steel sheet, and manufacturing method thereof - Google Patents
High-hardness steel sheet, and manufacturing method thereof Download PDFInfo
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- EP4324954A2 EP4324954A2 EP24150998.3A EP24150998A EP4324954A2 EP 4324954 A2 EP4324954 A2 EP 4324954A2 EP 24150998 A EP24150998 A EP 24150998A EP 4324954 A2 EP4324954 A2 EP 4324954A2
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- steel sheet
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 103
- 239000010959 steel Substances 0.000 title claims abstract description 103
- 238000004519 manufacturing process Methods 0.000 title abstract description 19
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 58
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 46
- 238000001816 cooling Methods 0.000 claims abstract description 41
- 229910000734 martensite Inorganic materials 0.000 claims abstract description 31
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 28
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 26
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 19
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 19
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 12
- 239000011572 manganese Substances 0.000 claims description 46
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 45
- 239000010936 titanium Substances 0.000 claims description 24
- 239000010955 niobium Substances 0.000 claims description 19
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims description 17
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 16
- 239000010703 silicon Substances 0.000 claims description 16
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 14
- 229910052719 titanium Inorganic materials 0.000 claims description 12
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 10
- 229910052758 niobium Inorganic materials 0.000 claims description 10
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims description 9
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims description 9
- 229910052796 boron Inorganic materials 0.000 claims description 9
- 239000011733 molybdenum Substances 0.000 claims description 9
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 8
- 229910052782 aluminium Inorganic materials 0.000 claims description 8
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 claims description 8
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 claims description 8
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 7
- 239000012535 impurity Substances 0.000 claims description 7
- 229910000859 α-Fe Inorganic materials 0.000 claims description 6
- 229910001563 bainite Inorganic materials 0.000 claims description 5
- 239000000203 mixture Substances 0.000 abstract description 8
- 238000000034 method Methods 0.000 abstract description 4
- 239000011651 chromium Substances 0.000 description 28
- 230000000052 comparative effect Effects 0.000 description 9
- 230000009466 transformation Effects 0.000 description 8
- 230000000694 effects Effects 0.000 description 6
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 229910001566 austenite Inorganic materials 0.000 description 4
- 238000005098 hot rolling Methods 0.000 description 4
- 238000003303 reheating Methods 0.000 description 3
- 238000005096 rolling process Methods 0.000 description 3
- 238000005275 alloying Methods 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 230000006911 nucleation Effects 0.000 description 2
- 238000010899 nucleation Methods 0.000 description 2
- 229910001562 pearlite Inorganic materials 0.000 description 2
- 238000004886 process control Methods 0.000 description 2
- QIVUCLWGARAQIO-OLIXTKCUSA-N (3s)-n-[(3s,5s,6r)-6-methyl-2-oxo-1-(2,2,2-trifluoroethyl)-5-(2,3,6-trifluorophenyl)piperidin-3-yl]-2-oxospiro[1h-pyrrolo[2,3-b]pyridine-3,6'-5,7-dihydrocyclopenta[b]pyridine]-3'-carboxamide Chemical compound C1([C@H]2[C@H](N(C(=O)[C@@H](NC(=O)C=3C=C4C[C@]5(CC4=NC=3)C3=CC=CN=C3NC5=O)C2)CC(F)(F)F)C)=C(F)C=CC(F)=C1F QIVUCLWGARAQIO-OLIXTKCUSA-N 0.000 description 1
- HFGHRUCCKVYFKL-UHFFFAOYSA-N 4-ethoxy-2-piperazin-1-yl-7-pyridin-4-yl-5h-pyrimido[5,4-b]indole Chemical compound C1=C2NC=3C(OCC)=NC(N4CCNCC4)=NC=3C2=CC=C1C1=CC=NC=C1 HFGHRUCCKVYFKL-UHFFFAOYSA-N 0.000 description 1
- 239000003216 Oxystearin Substances 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000000265 homogenisation Methods 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 150000001247 metal acetylides Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- AYOOGWWGECJQPI-NSHDSACASA-N n-[(1s)-1-(5-fluoropyrimidin-2-yl)ethyl]-3-(3-propan-2-yloxy-1h-pyrazol-5-yl)imidazo[4,5-b]pyridin-5-amine Chemical compound N1C(OC(C)C)=CC(N2C3=NC(N[C@@H](C)C=4N=CC(F)=CN=4)=CC=C3N=C2)=N1 AYOOGWWGECJQPI-NSHDSACASA-N 0.000 description 1
- VOVZXURTCKPRDQ-CQSZACIVSA-N n-[4-[chloro(difluoro)methoxy]phenyl]-6-[(3r)-3-hydroxypyrrolidin-1-yl]-5-(1h-pyrazol-5-yl)pyridine-3-carboxamide Chemical compound C1[C@H](O)CCN1C1=NC=C(C(=O)NC=2C=CC(OC(F)(F)Cl)=CC=2)C=C1C1=CC=NN1 VOVZXURTCKPRDQ-CQSZACIVSA-N 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 238000004881 precipitation hardening Methods 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
Classifications
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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
- C21D8/0221—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
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/18—Hardening; Quenching with or without subsequent tempering
-
- 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
-
- 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
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/54—Ferrous alloys, e.g. steel alloys containing chromium with nickel with boron
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/002—Bainite
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/005—Ferrite
-
- 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
- C21D2211/008—Martensite
Definitions
- the present disclosure relates to a high-hardness steel sheet used in various fields and a manufacturing method thereof .
- a steel sheet having high hardness is excellent in terms of wear resistance and load supporting ability, thus guaranteeing long service life as well as durability, and is used in various components.
- a steel grade is defined on the basis of Brinell hardness, and steel is manufactured to have various levels of hardness, from a Brinell hardness (HB) grade of 350 to a HB grade of 600, according to the related art.
- HB Brinell hardness
- a steel sheet having high hardness also has high strength, and thus may even be used in a field requiring a structure having high strength, such as a collision member or a reinforcing member.
- the steel sheet described above may have good economic value in terms of lightweightness and efficiency.
- a steel sheet is phase-transformed to a martensite or bainite structure in a cooling process from an austenite temperature range to room temperature, so high hardness and strength, which a low temperature transformation structure has, are generally provided.
- An aspect of the present disclosure may provide a high-hardness steel sheet having a Brinell hardness of 500 HB or more in which a steel composition is set using a minimum carbon content relation for obtaining a Brinell hardness of 500 HB or more.
- Another aspect of the present disclosure may provide a method of manufacturing a high-hardness steel sheet having a Brinell hardness of 500 HB or more by setting a steel composition according to a minimum carbon content relation for obtaining a Brinell hardness of 500 HB or more.
- a high-hardness steel sheet having a Brinell hardness of 500 HB or more the steel sheet manufactured by including cooling of a hot rolled steel sheet, includes carbon (C) : 0.05 wt% to 0.3 wt%, silicon (Si): 0.5 wt% or less (excluding 0%), manganese (Mn) : 2.5 wt% or less (excluding 0%), chrome (Cr): 1.5 wt% or less (excluding 0%), molybdenum (Mo) : 1.0wt% or less (excluding 0%), nickel (Ni) : 1.0 wt% or less (excluding 0%), niobium (Nb) : 0.1 wt% or less (excluding 0%), titanium (Ti): 0.1 wt% or less (excluding 0%), vanadium (V) : 0.1 wt% or less (excluding 0%), boron (B) : 0.01 wt% or less (excluding 0%), aluminum
- Mn, Si, Cr, Ni, and Mo are values representing the content of each element by wt%
- C.R. is a value representing a cooling rate during cooling of a hot-rolled steel sheet, and the unit thereof is °C/sec.
- a method of manufacturing a high-hardness steel sheet includes hot-rolling and cooling a steel slab including carbon (C): 0.05 wt% to 0.3 wt%, silicon (Si): 0.5 wt% or less (excluding 0%), manganese (Mn): 2.5 wt% or less (excluding 0%), chrome (Cr) : 1.5 wt% or less (excluding 0%), molybdenum (Mo): 1.0 wt% or less (excluding 0%), nickel (Ni) : 1.0 wt% or less (excluding 0%), niobium (Nb): 0.1 wt% or less (excluding 0%), titanium (Ti): 0.1 wt% or less (excluding 0%), vanadium (V) : 0.1 wt% or less
- Mn, Si, Cr, Ni, and Mo are values representing the content of each element by wt%
- C.R. is a value representing a cooling rate during cooling of a hot-rolled steel sheet, and the unit thereof is °C/sec.
- a component of a more economical and unified steel sheet may be designed.
- the prior art related to a high-hardness steel sheet has proposed various components and process control methods in order to obtain a level of hardness required, according to the components, but fails to provide a component criteria for unified hardness acquisition.
- the present inventors have conducted studies and experiments on the conditions of component design for securing a required level of hardness, when a microstructure of a steel sheet is formed to have 95 vol. % or more of a martensite structure in order to secure a high level of hardness and strength, and the present invention has been completed on the basis of the results thereof.
- one of the main technical features of the present invention is to provide the conditions of a component design for securing a required level of hardness when a microstructure of a steel sheet is formed as 95 vol.% or more of a martensite structure in order to secure high hardness and strength, and thus, more economically manufacturing a microstructure including 95 vol.% or more of a martensite phase and a steel sheet having a Brinell hardness of 500 HB or more, and obtaining unified hardness.
- the content of carbon (C) may be 0.05% to 0.3%.
- the content of carbon (C) may be 0.19 wt% to 0.3%.
- the content of silicon (Si) may be 0.5% or less (excluding 0%).
- Silicon is a preferred alloying element in applications in which hardness is used, because silicon increases the wear resistance of steel. However, when an amount of Si is excessive, surface properties and plating properties of the steel become poor, and a complete austenitization may not be performed during reheating.
- the content of silicon (Si) may be 0.21% to 0.5%.
- the content of silicon (Si) may be 0.253% to 0.34%.
- Manganese (Mn) and chrome (Cr) are elements significantly lowering martensite transformation temperatures, and manganese and chrome are elements, which may be used economically as low-cost elements, since manganese and chrome have an effect of reducing a transformation temperature less than that of carbon, among elements generally added to steel.
- An upper limit of the manganese content is preferably limited to 2.5%, and an upper limit of the chromium content is preferably limited to 1.5%.
- austenite may remain at room temperature, so 95 vol.% or more of a martensitic structure, a targeted amount, may not be obtained.
- the content of manganese may be 1.4% to 2.5%.
- the content of manganese may be 2.1% to 2.5%.
- Molybdenum (Mo) and nickel (Ni) are elements lowering a martensite transformation start temperature.
- a degree of lowering a martensite transformation start temperature is smaller than those of Mn and Cr. Due to being relatively expensive elements, an upper limit of an addition amount of each of these elements is preferably limited to 1.0%.
- Each of niobium (Nb) and titanium (Ti) may be added in an amount of 0.1% or less (excluding 0%), and may have an effect of improving the impact characteristics of a steel sheet through austenite grain refinement.
- the excessive addition of Nb and Ti may cause coarsening of Nb carbonitride, fixing grain boundaries, so a crystal grain refinement effect may be lost.
- an upper limit of each of Nb and Ti is preferably limited to 0.1%.
- Ti when B is added, Ti may be essentially added to protect B from N. Titanium (Ti) first reacts with carbon or nitrogen in steel, so TiC or TiN is formed. Thus, an addition effect of boron (B) may be increased. In this case, the content of titanium (Ti) may satisfy Relation 2 depending on stoichiometry, with respect to an amount of nitrogen in steel. Ti wt % > N wt % ⁇ 3.42
- V Vanadium (V): 0.1% or less (excluding 0%)
- Vanadium (V) may be added in an amount of 0.1% or less (excluding 0%), and may serve to prevent precipitation hardening through the formation of fine V carbides and the deterioration of physical properties of a welded portion.
- an addition amount of V is excessive, the effect described above may be reduced due to the coarsening of a carbide, so that an upper limit of the content of V is preferably limited to 0.1%.
- B Boron (B) may be added in an amount of 0.01% or less (excluding 0%), and B is an element significantly increasing hardenability of steel by inhibiting nucleation of ferrite and pearlite. Even when a thickness of steel is great, utilization thereof is significant.
- a final microstructure may be provided as 95 vol.% or more of martensite.
- a manufacturing method thereof is not particularly limited, so B may be added to secure hardenability as required. However, when the content of B is excessively added, B may rather act as a nucleation site on ferrite or pearlite to deteriorate hardenability, so an upper limit of the content of B is preferably limited to 0.01%.
- Aluminum (Al) is added for deoxidization and grain refinement, and the content of Al is preferably limited to 0.1% or less (excluding 0%).
- the remainder excluding elements described above include iron (Fe) and other unavoidable impurities.
- a minimum content of carbon (C) may satisfy Relation (1).
- C a minimum content of carbon C ⁇ 0.481 ⁇ 0.104 Mn ⁇ 0.035 Si ⁇ 0.088 Cr ⁇ 0.054 Ni ⁇ 0.035 Mo ⁇ 0.0003 C .R .
- Mn, Si, Cr, Ni, and Mo are values representing the content of each element by wt%
- C.R. is a value representing a cooling rate during cooling of a hot-rolled steel sheet, and the unit thereof is °C/sec.
- Relation (1) represents a minimum content of a carbon (C) for obtaining a Brinell hardness of 500 HB or more from a composition of silicon (Si), manganese (Mn), chrome (Cr), molybdenum (Mo), nickel (Ni), and chrome (Cr).
- Relation (1) may be designed using, for example, Relation (3) .
- HB Brinell hardness 100.4 + 830.5 * C + 86.5 * Mn + 28.8 * Si + 73.4 * Cr + 44.5 * Ni + 28.8 * Mo + 0.252 * C .R .
- C, Mn, Si, Cr, Ni, and Mo are values representing the content of each element by wt%
- C.R. is a value representing a cooling rate during cooling of a hot-rolled steel sheet, and the unit thereof is °C/sec.
- Relation (1) with respect to a minimum carbon content for HB ⁇ 500 may be derived from Relation (3).
- Relation (3) by using Relation (3) within a steel sheet component range of the present invention, proper alloying element design conditions to obtain any required level of hardness of 350 HB or more may be derived.
- a microstructure of a steel sheet according to the present invention may include 95 vol.% or more of a martensite phase.
- the microstructure of a steel sheet according to the present invention may include one or two of ferrite and bainite, in an amount of less than 5.0 vol.%, as a second phase structure, other than martensite.
- the steel sheet according to the present invention may have Brinell hardness of 500 HB or more.
- a steel slab including carbon (C): 0.05 wt% to 0.3 wt%, silicon (Si): 0.5 wt% or less (excluding 0%), manganese (Mn) : 2.5 wt% or less (excluding 0%), chrome (Cr): 1.5 wt% or less (excluding 0%), molybdenum (Mo): 1.0 wt% or less (excluding 0%), nickel (Ni) : 1.0 wt% or less (excluding 0%), niobium (Nb): 0.1 wt% or less (excluding 0%), titanium (Ti): 0.1 wt% or less (excluding 0%), vanadium (V): 0.1 wt% or less (excluding 0%), boron (B): 0.01 wt% or less (excluding 0%), aluminum (Al): 0.1 wt% or less (excluding 0%), a balance of iron (Fe): 1.0 wt% or less (excluding 0%), manganese (M
- a minimum content of carbon (C) in the steel slab satisfies Relation (1).
- C a minimum content of carbon C ⁇ 0.481 ⁇ 0.104 Mn ⁇ 0.035 Si ⁇ 0.088 Cr ⁇ 0.054 Ni ⁇ 0.035 Mo ⁇ 0.0003 C .R .
- Mn, Si, Cr, Ni, and Mo are values representing the content of each element by wt%
- C.R. is a value representing a cooling rate during cooling of a hot-rolled steel sheet, and the unit thereof is °C/sec.
- a steel slab Before the steel slab is hot-rolled as a hot-rolled steel sheet, a steel slab may be reheated.
- Conditions for reheating a slab are not particularly limited, and the conditions are sufficient as long as homogenization is allowed.
- a slab reheating temperature is preferably 1100°C to 1300°C.
- the hot-rolling conditions are preferably not limited, and a hot finish rolling temperature is sufficient as long as austenitization is allowed.
- the hot finish rolling temperature may be, for example, 870°C to 930°C, and whole hot-rolling may be performed within a temperature range of 1150°C to a hot finish rolling temperature, after extraction from a heating furnace.
- a cooling rate during cooling the hot-rolled steel sheet is not preferably limited while a cooling rate allows 95 vol.% or more of a martensite phase to be obtained.
- the cooling rate is 20°C/sec or more, and preferably, 20°C/sec to 150°C/sec.
- a cooling end temperature during cooling the hot-rolled steel sheet is the Ms point (a martensite transformation start temperature) or below, and is not particularly limited as long as a cooling end temperature allows 95 vol.% or more of a martensite phase to be obtained.
- compositions of steels of Table 1 satisfy a composition range of the present invention.
- a second phase structure of Table 2 indicates a second phase structure, other than martensite. Moreover, a structure other than a second phase structure is martensite, and 100% martensite is referred to as 100%M.
- F indicates ferrite
- B indicates bainite
- M indicates martensite
- a Brinell hardness (HB) value is 500 HB or more.
- a high-hardness steel sheet the steel sheet provided by cooling a hot rolled steel sheet, comprising:
- a method of manufacturing a high-hardness steel sheet comprising: hot-rolling and cooling a steel slab including carbon (C) : 0.05 wt% to 0.3 wt%, silicon (Si): 0.5 wt% or less (excluding 0%), manganese (Mn): 2.5 wt% or less (excluding 0%), chrome (Cr): 1.5 wt% or less (excluding 0%), molybdenum (Mo) : 1.0 wt% or less (excluding 0%), nickel (Ni): 1.0 wt% or less (excluding 0%), niobium (Nb): 0.1 wt% or less (excluding 0%), titanium (Ti): 0.1 wt% or less (excluding 0%), vanadium (V): 0.1 wt% or less (excluding 0%), boronitride, silicon (Si): 0.5 wt% or less (excluding 0%), manganese (Mn): 2.5 wt% or less (excluding 0%),
- a cooling end temperature during the cooling the hot-rolled steel sheet is the Ms point (a martensite transformation start temperature) or below.
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Abstract
Description
- The present disclosure relates to a high-hardness steel sheet used in various fields and a manufacturing method thereof .
- A steel sheet having high hardness is excellent in terms of wear resistance and load supporting ability, thus guaranteeing long service life as well as durability, and is used in various components.
- In detail, in the case of wear-resistant steel, a steel grade is defined on the basis of Brinell hardness, and steel is manufactured to have various levels of hardness, from a Brinell hardness (HB) grade of 350 to a HB grade of 600, according to the related art.
- Moreover, a steel sheet having high hardness also has high strength, and thus may even be used in a field requiring a structure having high strength, such as a collision member or a reinforcing member. In addition, the steel sheet described above may have good economic value in terms of lightweightness and efficiency.
- In the case of the high-hardness steel sheet described above, a steel sheet is phase-transformed to a martensite or bainite structure in a cooling process from an austenite temperature range to room temperature, so high hardness and strength, which a low temperature transformation structure has, are generally provided.
- However, in the prior art, various components and process control methods are used to obtain the required hardness according to a component, but a criteria for unified hardness acquisition is not provided.
- An aspect of the present disclosure may provide a high-hardness steel sheet having a Brinell hardness of 500 HB or more in which a steel composition is set using a minimum carbon content relation for obtaining a Brinell hardness of 500 HB or more.
- Another aspect of the present disclosure may provide a method of manufacturing a high-hardness steel sheet having a Brinell hardness of 500 HB or more by setting a steel composition according to a minimum carbon content relation for obtaining a Brinell hardness of 500 HB or more.
- According to an aspect of the present disclosure, a high-hardness steel sheet having a Brinell hardness of 500 HB or more, the steel sheet manufactured by including cooling of a hot rolled steel sheet, includes carbon (C) : 0.05 wt% to 0.3 wt%, silicon (Si): 0.5 wt% or less (excluding 0%), manganese (Mn) : 2.5 wt% or less (excluding 0%), chrome (Cr): 1.5 wt% or less (excluding 0%), molybdenum (Mo) : 1.0wt% or less (excluding 0%), nickel (Ni) : 1.0 wt% or less (excluding 0%), niobium (Nb) : 0.1 wt% or less (excluding 0%), titanium (Ti): 0.1 wt% or less (excluding 0%), vanadium (V) : 0.1 wt% or less (excluding 0%), boron (B) : 0.01 wt% or less (excluding 0%), aluminum (Al) : 0.1 wt% or less (excluding 0%), a balance of iron (Fe) and other unavoidable impurities; has a minimum content of carbon (C) satisfying Relation (1); and has a microstructure including 95 vol.% or more of a martensite phase.
- Here, Mn, Si, Cr, Ni, and Mo are values representing the content of each element by wt%, C.R. is a value representing a cooling rate during cooling of a hot-rolled steel sheet, and the unit thereof is °C/sec.
- According to another aspect of the present disclosure, a method of manufacturing a high-hardness steel sheet, the method of manufacturing a steel sheet, having a microstructure including 95 vol.% or more of a martensite phase and a Brinell hardness of 500 HB or more, includes hot-rolling and cooling a steel slab including carbon (C): 0.05 wt% to 0.3 wt%, silicon (Si): 0.5 wt% or less (excluding 0%), manganese (Mn): 2.5 wt% or less (excluding 0%), chrome (Cr) : 1.5 wt% or less (excluding 0%), molybdenum (Mo): 1.0 wt% or less (excluding 0%), nickel (Ni) : 1.0 wt% or less (excluding 0%), niobium (Nb): 0.1 wt% or less (excluding 0%), titanium (Ti): 0.1 wt% or less (excluding 0%), vanadium (V) : 0.1 wt% or less (excluding 0%), boron (B) : 0.01 wt% or less (excluding 0%), aluminum (Al): 0.1 wt% or less (excluding 0%), a balance of iron (Fe) and other unavoidable impurities, as a hot-rolled steel sheet, wherein a minimum content of carbon (C) satisfies Relation(1).
- Here, Mn, Si, Cr, Ni, and Mo are values representing the content of each element by wt%, C.R. is a value representing a cooling rate during cooling of a hot-rolled steel sheet, and the unit thereof is °C/sec.
- According to an exemplary embodiment in the present disclosure, in order to manufacture a steel sheet including a microstructure having 95 vol.% or more of a martensite phase and Brinell hardness of 500 HB or more, a component of a more economical and unified steel sheet may be designed.
- The prior art related to a high-hardness steel sheet has proposed various components and process control methods in order to obtain a level of hardness required, according to the components, but fails to provide a component criteria for unified hardness acquisition.
- Therefore, the present inventors have conducted studies and experiments on the conditions of component design for securing a required level of hardness, when a microstructure of a steel sheet is formed to have 95 vol. % or more of a martensite structure in order to secure a high level of hardness and strength, and the present invention has been completed on the basis of the results thereof.
- In other words, one of the main technical features of the present invention is to provide the conditions of a component design for securing a required level of hardness when a microstructure of a steel sheet is formed as 95 vol.% or more of a martensite structure in order to secure high hardness and strength, and thus, more economically manufacturing a microstructure including 95 vol.% or more of a martensite phase and a steel sheet having a Brinell hardness of 500 HB or more, and obtaining unified hardness.
- Hereinafter, a steel sheet according to a preferred aspect of the present invention will be described.
- The content of carbon (C) may be 0.05% to 0.3%.
- When the content of carbon is less than 0.05%, it may be difficult for martensitic transformation from an austenite region to occur during cooling. When the content of carbon exceeds 0.3%, it may be difficult to ensure stability of a component due to increased brittleness of steel.
- The content of carbon (C) may be 0.19 wt% to 0.3%.
- The content of silicon (Si) may be 0.5% or less (excluding 0%).
- Silicon is a preferred alloying element in applications in which hardness is used, because silicon increases the wear resistance of steel. However, when an amount of Si is excessive, surface properties and plating properties of the steel become poor, and a complete austenitization may not be performed during reheating.
- The content of silicon (Si) may be 0.21% to 0.5%. The content of silicon (Si) may be 0.253% to 0.34%.
- Manganese (Mn) and chrome (Cr) are elements significantly lowering martensite transformation temperatures, and manganese and chrome are elements, which may be used economically as low-cost elements, since manganese and chrome have an effect of reducing a transformation temperature less than that of carbon, among elements generally added to steel.
- An upper limit of the manganese content is preferably limited to 2.5%, and an upper limit of the chromium content is preferably limited to 1.5%.
- When the contents of manganese and chrome are excessively high, austenite may remain at room temperature, so 95 vol.% or more of a martensitic structure, a targeted amount, may not be obtained.
- The content of manganese may be 1.4% to 2.5%. The content of manganese may be 2.1% to 2.5%.
- Molybdenum (Mo) and nickel (Ni) are elements lowering a martensite transformation start temperature.
- However, a degree of lowering a martensite transformation start temperature is smaller than those of Mn and Cr. Due to being relatively expensive elements, an upper limit of an addition amount of each of these elements is preferably limited to 1.0%.
- Each of niobium (Nb) and titanium (Ti) may be added in an amount of 0.1% or less (excluding 0%), and may have an effect of improving the impact characteristics of a steel sheet through austenite grain refinement. However, the excessive addition of Nb and Ti may cause coarsening of Nb carbonitride, fixing grain boundaries, so a crystal grain refinement effect may be lost. Thus, an upper limit of each of Nb and Ti is preferably limited to 0.1%.
- On the other hand, when B is added, Ti may be essentially added to protect B from N. Titanium (Ti) first reacts with carbon or nitrogen in steel, so TiC or TiN is formed. Thus, an addition effect of boron (B) may be increased. In this case, the content of titanium (Ti) may satisfy Relation 2 depending on stoichiometry, with respect to an amount of nitrogen in steel.
- Vanadium (V) may be added in an amount of 0.1% or less (excluding 0%), and may serve to prevent precipitation hardening through the formation of fine V carbides and the deterioration of physical properties of a welded portion.
- When an addition amount of V is excessive, the effect described above may be reduced due to the coarsening of a carbide, so that an upper limit of the content of V is preferably limited to 0.1%.
- Boron (B) may be added in an amount of 0.01% or less (excluding 0%), and B is an element significantly increasing hardenability of steel by inhibiting nucleation of ferrite and pearlite. Even when a thickness of steel is great, utilization thereof is significant.
- In the present invention, a final microstructure may be provided as 95 vol.% or more of martensite. A manufacturing method thereof is not particularly limited, so B may be added to secure hardenability as required. However, when the content of B is excessively added, B may rather act as a nucleation site on ferrite or pearlite to deteriorate hardenability, so an upper limit of the content of B is preferably limited to 0.01%.
- Aluminum (Al) is added for deoxidization and grain refinement, and the content of Al is preferably limited to 0.1% or less (excluding 0%).
- The remainder excluding elements described above include iron (Fe) and other unavoidable impurities.
-
- Here, Mn, Si, Cr, Ni, and Mo are values representing the content of each element by wt%, C.R. is a value representing a cooling rate during cooling of a hot-rolled steel sheet, and the unit thereof is °C/sec.
- Relation (1) represents a minimum content of a carbon (C) for obtaining a Brinell hardness of 500 HB or more from a composition of silicon (Si), manganese (Mn), chrome (Cr), molybdenum (Mo), nickel (Ni), and chrome (Cr).
- Even when the content of carbon (C) satisfies 0.05 wt% to 0.3 wt%, in a case in which Relation (1) is not satisfied, a Brinell hardness of 500 HB or more may not be obtained.
-
- Here, C, Mn, Si, Cr, Ni, and Mo are values representing the content of each element by wt%, C.R. is a value representing a cooling rate during cooling of a hot-rolled steel sheet, and the unit thereof is °C/sec.
- Relation (1) with respect to a minimum carbon content for HB ≥500 may be derived from Relation (3).
- Moreover, by using Relation (3) within a steel sheet component range of the present invention, proper alloying element design conditions to obtain any required level of hardness of 350 HB or more may be derived.
- A microstructure of a steel sheet according to the present invention may include 95 vol.% or more of a martensite phase.
- When a fraction of the martensite phase is less than 95 vol.%, it may be difficult to secure targeted strength and hardness.
- The microstructure of a steel sheet according to the present invention may include one or two of ferrite and bainite, in an amount of less than 5.0 vol.%, as a second phase structure, other than martensite.
- The steel sheet according to the present invention may have Brinell hardness of 500 HB or more.
- Hereinafter, a method of manufacturing a steel sheet according to another preferred aspect of the present invention will be described.
- In a method of manufacturing a steel sheet according to another preferred aspect of the present invention, after a steel slab including carbon (C): 0.05 wt% to 0.3 wt%, silicon (Si): 0.5 wt% or less (excluding 0%), manganese (Mn) : 2.5 wt% or less (excluding 0%), chrome (Cr): 1.5 wt% or less (excluding 0%), molybdenum (Mo): 1.0 wt% or less (excluding 0%), nickel (Ni) : 1.0 wt% or less (excluding 0%), niobium (Nb): 0.1 wt% or less (excluding 0%), titanium (Ti): 0.1 wt% or less (excluding 0%), vanadium (V): 0.1 wt% or less (excluding 0%), boron (B): 0.01 wt% or less (excluding 0%), aluminum (Al): 0.1 wt% or less (excluding 0%), a balance of iron (Fe) and other unavoidable impurities is hot-rolled as a hot-rolled steel sheet, the hot-rolled steel sheet is cooled, so a steel sheet having a martensite phase including 95 vol.% or more of a microstructure and 500 HB or more of Brinell hardness is manufactured.
-
- Here, Mn, Si, Cr, Ni, and Mo are values representing the content of each element by wt%, C.R. is a value representing a cooling rate during cooling of a hot-rolled steel sheet, and the unit thereof is °C/sec.
- Before the steel slab is hot-rolled as a hot-rolled steel sheet, a steel slab may be reheated.
- Conditions for reheating a slab are not particularly limited, and the conditions are sufficient as long as homogenization is allowed.
- A slab reheating temperature is preferably 1100°C to 1300°C.
- The hot-rolling conditions are preferably not limited, and a hot finish rolling temperature is sufficient as long as austenitization is allowed.
- The hot finish rolling temperature may be, for example, 870°C to 930°C, and whole hot-rolling may be performed within a temperature range of 1150°C to a hot finish rolling temperature, after extraction from a heating furnace.
- A cooling rate during cooling the hot-rolled steel sheet is not preferably limited while a cooling rate allows 95 vol.% or more of a martensite phase to be obtained. For example, the cooling rate is 20°C/sec or more, and preferably, 20°C/sec to 150°C/sec.
- A cooling end temperature during cooling the hot-rolled steel sheet is the Ms point (a martensite transformation start temperature) or below, and is not particularly limited as long as a cooling end temperature allows 95 vol.% or more of a martensite phase to be obtained.
- Hereinafter, the present disclosure will be described in greater detail with reference to examples. The examples are only for illustrating the present invention, and the present invention is not limited thereto.
- An experiment was conducted using 17 types of steel A to Q having the compositions (unit: wt%) illustrated in Table 1.
- The compositions of steels of Table 1 satisfy a composition range of the present invention.
- After a steel sheet having the steel composition of Table 1 while having a thickness of 30 mm and a width of 200 mm was manufactured, the steel sheet was reheated for 180 minutes at 1200°C. Next, the steel sheet, having been reheated, was hot-rolled in a hot finish temperature range of 900°C, and a hot-rolled steel sheet having a thickness of 3.0 mm was manufactured. Thereafter, the steel sheet was cooled to 200°C at a cooling rate of Table 2.
- Brinell hardness (HB) and a microstructure of the hot-rolled steel sheet manufactured as described above were measured, and results thereof are illustrated in Table 2.
- A second phase structure of Table 2 indicates a second phase structure, other than martensite. Moreover, a structure other than a second phase structure is martensite, and 100% martensite is referred to as 100%M.
- In the second phase structure described above, F indicates ferrite, B indicates bainite, and M indicates martensite.
- Moreover, in Table 2, a required carbon content obtained by Relation (1), an actual carbon content, and a difference between the actual content and the required carbon content are illustrated.
[Table 1] Ste el C Si Mn Cr Mo Ni Al Ti Nb V B A 0.081 0.298 1.85 0.498 0.101 0.008 0.03 0.006 0.032 0.006 0.0002 B 0.121 0.351 2.11 0.313 0.798 0.012 0.032 0.025 0.023 0.005 0.0017 C 0.195 0.354 2.01 0.297 0.006 0.812 0.031 0.029 0.025 0.003 0.0016 D 0.152 0.248 1.49 0.296 0.008 0.011 0.033 0.03 0.056 0.005 0.003 E 0.242 0.432 1.72 0.411 0.312 0.013 0.036 0.03 0.003 0.006 0.0033 F 0.148 0.243 1.48 0.607 0.012 0.005 0.034 0.029 0.004 0.004 0.0032 G 0.148 0.24 1.48 0.3 0.007 0.007 0.035 0.098 0.005 0.005 0.0033 H 0.297 0.253 1.51 0.3 0.211 0.006 0.035 0.03 0.007 0.002 0.0016 I 0.212 0.25 1.49 1.1 0.203 0.008 0.035 0.03 0.022 0.098 0.0029 J 0.2 0.249 1.47 0.3 0.011 0.021 0.03 0.029 0.005 0.003 0.0029 K 0.252 0.254 2.31 0.125 0.012 0.015 0.033 0.03 0.032 0.005 0.0028 L 0.198 0.243 1.49 0.297 0.015 0.023 0.034 0.03 0.008 0.004 0.0031 M 0.199 0.254 1.47 1.12 0.012 0.015 0.033 0.03 0.032 0.005 0.0028 N 0.2 0.207 1.47 0.3 0.011 0.014 0.034 0.098 0.045 0.002 0.0025 O 0.26 0.297 2.11 0.02 0.101 0.005 0.027 0.007 0.022 0.011 0.0003 P 0.27 0.212 1.51 0.52 0.112 0.012 0.021 0.005 0.023 0.012 0.0020 Q 0.232 0.491 1.78 0.298 0.005 0.003 0.026 0.021 0.015 0.055 0.0018 [Table 2] Classifi cation Ste el Ms (°C) Cooling rate (°C/sec) Required carbon content (wt.%,Relation 1) (i) Actual carbon content (wt .%) ② ②-① Brinell hardnes s (HB) Second phase structur e Comparat ive Example 1 A 432 100 0.200 0.081 -0.119 395 F8%,B11% Comparat ive Example 2 B 401 50 0.178 0.121 -0.057 445 F2%, B3% Inventiv e Example 1 C 381 50 0.174 0.195 0.021 519 B3% Comparat ive Example 3 D 433 50 0.275 0.152 -0.123 404 F1$. B4% Inventiv e Example2 E 387 35 0.229 0.242 0.013 505 F1%, B3% Inventiv e Examples E 379 70 0.218 0.242 0.024 523 100%M Comparat ive Example 4 F 425 50 0.249 0.148 -0.101 405 B4% Comparatve Example 5 G 434 20 0.286 0.148 -0.138 364 F6%, B7% Inventiv e Example4 H 380 50 0.266 0.297 0.031 531 B3% Inventiv e Examples I 379 35 0.202 0.212 0.010 511 100$M Comparat ive Example 6 J 411 35 0.281 0.2 -0.081 437 F2%, B2% Inventiv e Example6 K 372 100 0.190 0.252 0.062 551 100$M Comparat ive Example 7 L 417 35 0.279 0.198 -0.081 440 F2%, B2% Comparat ive Example 8 M 394 20 0.213 0.199 -0.014 491 F1%, B3% Comparat ive Example 9 N 417 70 0.272 0.2 -0.072 448 B4% Inventiv e Example7 O 377 80 0.222 0.26 0.038 527 B3% Inventiv e Examples P 386 50 0.251 0.27 0.019 510 B2% Inventiv e Example9 Q 396 100 0.222 0.232 0.010 502 B3% - As illustrated in Table 2, according to the present invention, in the case of Inventive Examples 1 through 9, in which an actual carbon content is larger than a required carbon content, it is confirmed that a Brinell hardness (HB) value is 500 HB or more.
- On the other hand, in the case of Comparative Examples 1 through 9, in which an actual carbon content is smaller than a required carbon content, it is confirmed that a value of Brinell hardness is less than 500 HB.
- While exemplary embodiments have been shown and described above, it will be apparent to those skilled in the art that modifications and variations could be made without departing from the scope of the present invention as defined by the appended claims.
- A high-hardness steel sheet, the steel sheet provided by cooling a hot rolled steel sheet, comprising:
- carbon (C): 0.05 wt% to 0.3 wt%, silicon (Si): 0.5 wt% or less (excluding 0%), manganese (Mn): 2.5 wt% or less (excluding 0%), chrome (Cr): 1.5 wt% or less (excluding 0%), molybdenum (Mo): 1.0 wt% or less (excluding 0%), nickel (Ni) : 1.0 wt% or less (excluding 0%), niobium (Nb): 0.1 wt% or less (excluding 0%), titanium (Ti): 0.1 wt% or less (excluding 0%), vanadium (V): 0.1 wt% or less (excluding 0%), boron (B): 0.01 wt% or less (excluding 0%), aluminum (Al): 0.1 wt% or less (excluding 0%), a balance of iron (Fe) and other unavoidable impurities;
- having a minimum content of carbon (C) satisfying Relation (1) ;
- having a microstructure comprising 95 vol.% or more of a martensite phase; and
- having a Brinell hardness of 500 HB or more,
- where Mn, Si, Cr, Ni, and Mo are values representing the content of each element by wt%, C.R. is a value representing a cooling rate during the cooling a hot-rolled steel sheet, and the unit thereof is °C/sec.
- The high-hardness steel sheet of aspect 1, wherein the microstructure includes one or two of ferrite and bainite, in an amount of less than 5.0 vol.%, as a second phase structure, other than martensite.
- The high-hardness steel sheet of aspect 1, wherein Relation (1) is derived from Relation (3),
- The high-hardness steel sheet of any one of aspects 1 to 3, wherein the content of carbon (C) is 0.19 wt% to 0.3 wt%.
- The high-hardness steel sheet of any one of aspects 1 to 3, wherein the content of silicon (Si) is 0.21 wt% to 0.5 wt%.
- The high-hardness steel sheet of any one of aspects 1 to 3, wherein the content of manganese is 1.4 wt% to 2.5 wt%.
- A method of manufacturing a high-hardness steel sheet, the method of manufacturing a steel sheet, having a microstructure comprising 95 vol. % or more of a martensite phase and a Brinell hardness of 500 HB or more, comprising: hot-rolling and cooling a steel slab including carbon (C) : 0.05 wt% to 0.3 wt%, silicon (Si): 0.5 wt% or less (excluding 0%), manganese (Mn): 2.5 wt% or less (excluding 0%), chrome (Cr): 1.5 wt% or less (excluding 0%), molybdenum (Mo) : 1.0 wt% or less (excluding 0%), nickel (Ni): 1.0 wt% or less (excluding 0%), niobium (Nb): 0.1 wt% or less (excluding 0%), titanium (Ti): 0.1 wt% or less (excluding 0%), vanadium (V): 0.1 wt% or less (excluding 0%), boron (B): 0.01 wt% or less (excluding 0%), aluminum (Al) : 0.1 wt% or less (excluding 0%), a balance of iron (Fe) and other unavoidable impurities, as a hot-rolled steel sheet, wherein a minimum content of carbon (C) satisfies Relation (1),
- The method of manufacturing a high-hardness steel sheet of aspect 7, wherein a cooling rate during the cooling the hot-rolled steel sheet is 20°C/sec to 150°C/sec.
- The method of manufacturing a high-hardness steel sheet of aspect 7 or 8, wherein a cooling end temperature during the cooling the hot-rolled steel sheet is the Ms point (a martensite transformation start temperature) or below.
- The method of manufacturing a high-hardness steel sheet of aspect 7 or 8, wherein the content of carbon (C) is 0.19% to 0.3%.
- The method of manufacturing a high-hardness steel sheet of aspect 7 or 8, wherein the content of silicon (Si) is 0.21% to 0.5%.
- The method of manufacturing a high-hardness steel sheet of aspect 7 or 8, wherein the content of manganese is 1.4% to 2.5%.
Claims (4)
- A high-hardness steel sheet, the steel sheet provided by cooling a hot rolled steel sheet, consisting of:carbon (C): 0.05 wt% to 0.3 wt%, silicon (Si): more than 0 wt% to 0.5 wt% or less, manganese (Mn): 1.4 wt% to 2.5 wt%, chrome (Cr): more than 0 wt% to 1.5 wt% or less, molybdenum (Mo): more than 0 wt% to 1.0 wt% or less, nickel (Ni): more than 0 wt% to 1.0 wt% or less, niobium (Nb): more than 0 wt% to 0.1 wt% or less, titanium (Ti): more than 0 wt% to 0.1 wt% or less, vanadium (V): more than 0 wt% to 0.1 wt% or less, boron (B): more than 0 wt% to 0.01 wt% or less, aluminum (Al): more than 0 wt% to 0.1 wt% or less, a balance of iron (Fe) and other unavoidable impurities;having a content of carbon (C) satisfying Relation (1);having a microstructure comprising 95 vol.% or more of a martensite phase; andwhere Mn, Si, Cr, Ni, and Mo are values representing the content of each element by wt%, C.R. is a value representing a cooling rate during the cooling a hot-rolled steel sheet, and the unit thereof is °C/sec.
- The high-hardness steel sheet of claim 1, wherein the microstructure includes one or two of ferrite and bainite, in an amount of less than 5.0 vol.%, as a second phase structure, other than martensite.
- The high-hardness steel sheet of any one of claims 1 and 2, wherein the content of carbon (C) is 0.19 wt% to 0.3 wt%.
- The high-hardness steel sheet of any one of claims 1 and 2, wherein the content of silicon (Si) is 0.21 wt% to 0.5 wt%.
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KR102031446B1 (en) * | 2017-12-22 | 2019-11-08 | 주식회사 포스코 | Wear resistant steel having excellent hardness and impact toughness and method of manufacturing the same |
KR102045646B1 (en) * | 2017-12-26 | 2019-11-15 | 주식회사 포스코 | Abrasion resistance steel having excellent homogeneous material properties and method for manufacturing the same |
KR102175570B1 (en) * | 2018-09-27 | 2020-11-06 | 주식회사 포스코 | Wear resistant steel having excellent hardness and impact toughness and method of manufacturing the same |
JP7163887B2 (en) * | 2019-08-21 | 2022-11-01 | Jfeスチール株式会社 | Wear-resistant steel with excellent fatigue resistance |
JP7163889B2 (en) * | 2019-08-21 | 2022-11-01 | Jfeスチール株式会社 | Manufacturing method for wear-resistant steel with excellent fatigue resistance |
DE102019215055A1 (en) * | 2019-09-30 | 2021-04-01 | Thyssenkrupp Steel Europe Ag | Process for manufacturing a steel product and a corresponding steel product |
CN113215488B (en) * | 2021-05-07 | 2022-06-17 | 马鞍山钢铁股份有限公司 | Heat-treatment-free NM360 wear-resistant steel plate and manufacturing method thereof |
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JP3425837B2 (en) * | 1996-03-28 | 2003-07-14 | 株式会社神戸製鋼所 | High-strength hot-rolled steel sheet, high-strength galvanized steel sheet excellent in pitting corrosion resistance and crushing properties, and methods for producing them |
KR100536828B1 (en) * | 1997-09-22 | 2006-02-28 | 카가쿠기쥬쯔죠 킨조쿠자이료 기쥬쯔켄큐죠 | Grain steel based on fine-ferrite and method thereof |
JP3736320B2 (en) * | 2000-09-11 | 2006-01-18 | Jfeスチール株式会社 | Abrasion-resistant steel with excellent toughness and delayed fracture resistance and method for producing the same |
WO2005106059A1 (en) * | 2004-04-28 | 2005-11-10 | Jfe Steel Corporation | Parts for machine construction and method for production thereof |
JP4374350B2 (en) * | 2006-04-11 | 2009-12-02 | 新日本製鐵株式会社 | High-hardness hot-rolled steel sheet excellent in weldability, workability, and high-speed impact penetration performance and method for producing the same |
JP5423806B2 (en) * | 2009-11-17 | 2014-02-19 | 新日鐵住金株式会社 | High toughness wear resistant steel and method for producing the same |
KR101271888B1 (en) * | 2010-12-23 | 2013-06-05 | 주식회사 포스코 | Thick Plate Having Excellent Wear Resistant And Low-Temperature Toughness, And Method For Manufacturing The Same |
BR112013025002B1 (en) * | 2011-03-29 | 2023-09-26 | Jfe Steel Corporation | THICK ABRASION RESISTANT STEEL SHEET AND METHOD FOR PRODUCING THE SAME |
CN102517509A (en) * | 2012-01-06 | 2012-06-27 | 江苏省沙钢钢铁研究院有限公司 | HB500 (Brinell Hardness 500) wear-resistant steel plate and preparation method thereof |
JP5966730B2 (en) * | 2012-07-30 | 2016-08-10 | Jfeスチール株式会社 | Abrasion resistant steel plate with excellent impact wear resistance and method for producing the same |
KR20150038590A (en) * | 2012-09-19 | 2015-04-08 | 제이에프이 스틸 가부시키가이샤 | Wear-resistant steel plate having excellent low-temperature toughness and corrosion wear resistance |
CN103146997B (en) * | 2013-03-28 | 2015-08-26 | 宝山钢铁股份有限公司 | A kind of low-alloy high-flexibility wear-resistant steel plate and manufacture method thereof |
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2015
- 2015-08-21 KR KR1020150117985A patent/KR101696094B1/en active IP Right Grant
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2016
- 2016-08-18 EP EP16839505.1A patent/EP3339464B1/en active Active
- 2016-08-18 WO PCT/KR2016/009079 patent/WO2017034216A1/en active Application Filing
- 2016-08-18 EP EP24150998.3A patent/EP4324954A3/en active Pending
- 2016-08-18 US US15/751,591 patent/US20180237875A1/en not_active Abandoned
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JP6843119B2 (en) | 2021-03-17 |
EP4324954A3 (en) | 2024-05-22 |
CN107923023B (en) | 2020-04-24 |
EP3339464B1 (en) | 2024-07-03 |
EP3339464A1 (en) | 2018-06-27 |
US20180237875A1 (en) | 2018-08-23 |
EP3339464A4 (en) | 2018-08-08 |
JP2018528325A (en) | 2018-09-27 |
KR101696094B1 (en) | 2017-01-13 |
WO2017034216A1 (en) | 2017-03-02 |
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