KR101771337B1 - Steel sheet with excellent corrosion resistance at cut end surface and method for manufacturing the same - Google Patents
Steel sheet with excellent corrosion resistance at cut end surface and method for manufacturing the same Download PDFInfo
- Publication number
- KR101771337B1 KR101771337B1 KR1020157033582A KR20157033582A KR101771337B1 KR 101771337 B1 KR101771337 B1 KR 101771337B1 KR 1020157033582 A KR1020157033582 A KR 1020157033582A KR 20157033582 A KR20157033582 A KR 20157033582A KR 101771337 B1 KR101771337 B1 KR 101771337B1
- Authority
- KR
- South Korea
- Prior art keywords
- less
- steel sheet
- layer
- coating layer
- steel
- Prior art date
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 175
- 239000010959 steel Substances 0.000 title claims abstract description 175
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 17
- 238000000034 method Methods 0.000 title claims description 26
- 230000007797 corrosion Effects 0.000 title abstract description 59
- 238000005260 corrosion Methods 0.000 title abstract description 59
- 239000002244 precipitate Substances 0.000 claims abstract description 57
- 239000012535 impurity Substances 0.000 claims abstract description 16
- 239000011247 coating layer Substances 0.000 claims description 57
- 238000007747 plating Methods 0.000 claims description 40
- 238000000137 annealing Methods 0.000 claims description 38
- 239000011701 zinc Substances 0.000 claims description 34
- 229910001208 Crucible steel Inorganic materials 0.000 claims description 33
- 239000011248 coating agent Substances 0.000 claims description 33
- 238000000576 coating method Methods 0.000 claims description 33
- 238000005096 rolling process Methods 0.000 claims description 31
- 229910052725 zinc Inorganic materials 0.000 claims description 31
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 30
- 239000010410 layer Substances 0.000 claims description 27
- 239000000049 pigment Substances 0.000 claims description 25
- 239000002335 surface treatment layer Substances 0.000 claims description 19
- 238000004381 surface treatment Methods 0.000 claims description 17
- 239000002131 composite material Substances 0.000 claims description 13
- 238000005097 cold rolling Methods 0.000 claims description 11
- 239000003973 paint Substances 0.000 claims description 11
- 239000000203 mixture Substances 0.000 claims description 10
- 230000009466 transformation Effects 0.000 claims description 8
- 229910052698 phosphorus Inorganic materials 0.000 claims description 6
- 238000000151 deposition Methods 0.000 claims description 3
- 230000008021 deposition Effects 0.000 claims description 3
- 238000005554 pickling Methods 0.000 claims description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 27
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 17
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 15
- 238000003303 reheating Methods 0.000 description 15
- 238000005520 cutting process Methods 0.000 description 14
- 239000000047 product Substances 0.000 description 12
- 238000005098 hot rolling Methods 0.000 description 9
- 230000009471 action Effects 0.000 description 6
- 238000009749 continuous casting Methods 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 238000001556 precipitation Methods 0.000 description 5
- 238000010008 shearing Methods 0.000 description 5
- 230000006866 deterioration Effects 0.000 description 4
- 239000006104 solid solution Substances 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 229910019142 PO4 Inorganic materials 0.000 description 3
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 3
- 238000005266 casting Methods 0.000 description 3
- ZCDOYSPFYFSLEW-UHFFFAOYSA-N chromate(2-) Chemical compound [O-][Cr]([O-])(=O)=O ZCDOYSPFYFSLEW-UHFFFAOYSA-N 0.000 description 3
- 239000010960 cold rolled steel Substances 0.000 description 3
- 238000005336 cracking Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- 239000010452 phosphate Substances 0.000 description 3
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 3
- 238000004080 punching Methods 0.000 description 3
- 230000003252 repetitive effect Effects 0.000 description 3
- 229910000077 silane Inorganic materials 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 238000004804 winding Methods 0.000 description 3
- 229910018134 Al-Mg Inorganic materials 0.000 description 2
- 229910018467 Al—Mg Inorganic materials 0.000 description 2
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 2
- 229910004298 SiO 2 Inorganic materials 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- 229910007570 Zn-Al Inorganic materials 0.000 description 2
- 229910007567 Zn-Ni Inorganic materials 0.000 description 2
- 229910007614 Zn—Ni Inorganic materials 0.000 description 2
- YRKCREAYFQTBPV-UHFFFAOYSA-N acetylacetone Chemical compound CC(=O)CC(C)=O YRKCREAYFQTBPV-UHFFFAOYSA-N 0.000 description 2
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 2
- 230000002411 adverse Effects 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 238000009713 electroplating Methods 0.000 description 2
- 230000000670 limiting effect Effects 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 238000001953 recrystallisation Methods 0.000 description 2
- 230000002829 reductive effect Effects 0.000 description 2
- 238000005728 strengthening Methods 0.000 description 2
- 238000009864 tensile test Methods 0.000 description 2
- 150000003568 thioethers Chemical class 0.000 description 2
- 229910052718 tin Inorganic materials 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- 238000009966 trimming Methods 0.000 description 2
- 238000007740 vapor deposition Methods 0.000 description 2
- 229910052726 zirconium Inorganic materials 0.000 description 2
- 239000004925 Acrylic resin Substances 0.000 description 1
- 229920000178 Acrylic resin Polymers 0.000 description 1
- 239000004593 Epoxy Substances 0.000 description 1
- 229910001335 Galvanized steel Inorganic materials 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 229910052787 antimony Inorganic materials 0.000 description 1
- 229910021538 borax Inorganic materials 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 229920006026 co-polymeric resin Polymers 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- UQGFMSUEHSUPRD-UHFFFAOYSA-N disodium;3,7-dioxido-2,4,6,8,9-pentaoxa-1,3,5,7-tetraborabicyclo[3.3.1]nonane Chemical compound [Na+].[Na+].O1B([O-])OB2OB([O-])OB1O2 UQGFMSUEHSUPRD-UHFFFAOYSA-N 0.000 description 1
- 238000004070 electrodeposition Methods 0.000 description 1
- 238000005868 electrolysis reaction Methods 0.000 description 1
- 239000008151 electrolyte solution Substances 0.000 description 1
- 229920006334 epoxy coating Polymers 0.000 description 1
- 239000003822 epoxy resin Substances 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 239000008397 galvanized steel Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 238000010422 painting Methods 0.000 description 1
- 238000007591 painting process Methods 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- 229920001225 polyester resin Polymers 0.000 description 1
- 239000004645 polyester resin Substances 0.000 description 1
- 229920005672 polyolefin resin Polymers 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 230000003405 preventing effect Effects 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000001226 reprecipitation Methods 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 235000010339 sodium tetraborate Nutrition 0.000 description 1
- 239000004328 sodium tetraborate Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
Classifications
-
- 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
- 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
- C23C2/34—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the shape of the material to be treated
- C23C2/36—Elongated material
- C23C2/40—Plates; Strips
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
- B21B1/22—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length
- B21B1/24—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length in a continuous or semi-continuous process
- B21B1/26—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length in a continuous or semi-continuous process by hot-rolling, e.g. Steckel hot mill
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B3/00—Rolling materials of special alloys so far as the composition of the alloy requires or permits special rolling methods or sequences ; Rolling of aluminium, copper, zinc or other non-ferrous metals
-
- 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
- B32B15/012—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 aluminium or an aluminium alloy
-
- 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
-
- 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
- C21D8/0236—Cold 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
- 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
- C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
- C21D9/54—Furnaces for treating strips or wire
- C21D9/56—Continuous furnaces for strip or wire
-
- 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
-
- 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
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
-
- 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
- C22C38/004—Very low carbon steels, i.e. having a carbon content of less than 0,01%
-
- 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
- C22C38/04—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
- C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
-
- 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
- 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
- C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
- C23C2/06—Zinc or cadmium or alloys based thereon
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Heat Treatment Of Sheet Steel (AREA)
- Coating With Molten Metal (AREA)
Abstract
A steel sheet excellent in corrosion resistance of a cut section and a method of manufacturing the same are provided. The steel sheet contains 0.001 to 0.1% of C, 4.0% or less of Si, 0.16 to 1.0% of Mn, 0.03% or less of P, 0.02% or less of S and 0.003 to 0.06% By weight and the balance of Fe and inevitable impurities, and the amount of Mn contained in the precipitate having a diameter of more than 0.5 μm is set to 100 mass ppm or less.
Description
TECHNICAL FIELD The present invention relates to a steel sheet which is mainly used for forming a surface treatment layer such as a zinc-based plated layer on a surface thereof and is suitable as a material for an electric appliance, office equipment, etc. in the room. The present invention relates to a steel sheet excellent in corrosion resistance of a cut section that does not have a sacrificial corrosion preventing action such as zinc, such as a shear section of a steel sheet, a tread surface, and a manufacturing method thereof.
The surface-treated steel sheet subjected to zinc plating, etc. is widely used as a product member of household appliances, office equipment and the like because of its excellent corrosion resistance. These product members are subjected to shearing, punching, punching, trimming or the like on a surface-treated steel sheet obtained by coating a surface treatment layer such as zinc-based plating or the like on one surface or both surfaces of the steel sheet in the production process Any mechanical cutting process can be molded into a desired shape.
Conventionally, the surface treated steel sheets used as these product members were generally closed with the product. However, by the Household Appliance Recycling Law, which was introduced in 2001, these members were reused (reused). However, in order to recover the product and use the member as a member of the same product again, the cutting surface (front surface, ridge surface, trimming surface, etc.) of the surface-treated steel sheet formed by mechanical cutting at the time of manufacturing the member, Red rust was generated on the surface to which no light was applied and thus it was not suitable for reuse. There is a risk of electric circuit damage due to peeling and rust of rust.
Galvanized steel sheet and the like, most of the area excluding the cutting section is sufficiently protected. Therefore, it has been considered that when the zinc-plated steel sheet or the like is used in the field of household electric appliances, the effect of the sacrificial method of zinc is likely to be applied to the cross section, and the corrosion resistance of the cross section has not been sufficiently examined.
It is considered that it is necessary to improve the corrosion resistance of the steel sheet to be the base material in order to fundamentally solve the problem of the lack of corrosion resistance which appears at the cross section of the zinc plated steel sheet or the like. Patent Document 1 discloses a steel sheet to be a base material in an amount of from 0.001 to 0.1% of C, not more than 0.1% of Si, not more than 0.1% of Si, 0.05 to 0.15%, P: not more than 0.02%, S: 0.001 to 0.010%, Al: 0.003 to 0.03%, Ti: 0.03 to 0.2%, Zr: 0.001 to 0.1% A steel plate is proposed. Patent Document 1 discloses that the corrosion resistance of a good cross section is obtained by limiting the amount of impurities contained in the steel and decreasing the Mn-based precipitates and the S-based precipitates.
On the other hand, a steel sheet used as a product member of household appliances, office equipment, etc., is also required to have a desired strength. BACKGROUND ART Conventionally, a steel sheet having a tensile strength (TS) of 270 MPa is frequently used for product members such as household appliances and business equipment. However, in recent years, for the purpose of reducing the weight of the product and the transportation cost, it is required to reduce the thickness of the steel sheet. For these reasons, there is a growing demand for high-tensile steel sheets having a tensile strength (TS) exceeding 440 MPa, which can maintain the strength even when the sheet thickness is thin as a material for home appliances and office equipment.
Patent Document 2 discloses a steel sheet as a base material in which the content of C is 0.0010 to 0.0080%, Si is 0.4% or less, Mn is 0.1% or less, , Al: not more than 0.05%, N: 0.0060 to 0.0200%, and further containing N and Al in a ratio of N content to Al content, N / Al 0.2 or more, further containing 0.0040% or more of solids (N), and the balance being Fe and inevitable impurities.
However, in the technique proposed in Patent Document 1, for the purpose of reducing Mn precipitates and S precipitates (MnS), the Mn content of the steel sheet is limited to 0.15% or less by mass%. As described above, when the content of Mn contributing to the improvement of steel strength is limited to 0.15% or less, a high tensile strength steel sheet having a tensile strength (TS) exceeding 440 MPa can not be obtained.
On the other hand, as proposed in Patent Document 2, in a high tensile strength steel sheet, the Mn content is set to 0.1% or more by mass% to increase the strength of the steel sheet. However, as the Mn content increases, the MnS precipitation amount in the steel sheet increases. The precipitate mainly composed of MnS is chemically active and easily soluble in water, so that when the precipitation amount of MnS increases, generation of rust from the precipitate becomes a problem. Therefore, for example, when the Mn content exceeds 0.15% by mass%, the generation of rust in the cut section of the steel sheet in particular can not be suppressed.
As described above, in the past, it has been very difficult to achieve both high strength and corrosion resistance of a steel sheet. Under such circumstances, a steel sheet excellent in corrosion resistance at the cutting section is strongly demanded also for a steel sheet containing Mn at a high concentration.
The present invention has been made in view of such circumstances, and an object of the present invention is to propose a steel sheet having a Mn content of more than 0.15% by mass and excellent in the corrosion resistance of a cutting section and its manufacturing method. The term "cut section" as used herein means a section of a steel sheet generated by subjecting a steel sheet to mechanical cutting such as shearing or punching.
In order to solve the above-mentioned problems, the inventors of the present invention have made extensive studies on various factors affecting the corrosion resistance of a steel sheet containing Mn in an amount exceeding 0.15% by mass, specifically, a steel sheet containing Mn in an amount of 0.16% Respectively.
As described above, the precipitate in the steel sheet, particularly the precipitate containing Mn, is a starting point of generation of rust and adversely affects the corrosion resistance of the steel sheet. Therefore, in order to improve the corrosion resistance of the steel sheet, it is preferable to minimize the precipitation amount of the precipitate containing Mn. However, in the case of a steel sheet containing 0.16% by mass or more of Mn by mass%, it is very difficult to suppress precipitation of precipitates containing Mn, for example, Mn-based sulfides including MnS.
Therefore, the inventors of the present invention have studied corrosion of a steel sheet in the atmosphere, particularly in a indoor use environment, and attempted to improve the corrosion resistance of the steel sheet by optimizing the form of the precipitate containing Mn. As a result, precipitates having a diameter larger than 0.5 占 퐉 among the precipitates containing Mn present in the steel sheet were liable to be a starting point of rust occurrence particularly, and adversely affected the corrosion resistance of the steel sheet.
Moreover, even when a precipitate having a diameter of more than 0.5 占 퐉 is present in the steel sheet among the precipitates containing Mn, if the amount of Mn contained in the precipitate having a diameter exceeding 0.5 占 퐉 is suppressed to 100 mass ppm or less, corrosion resistance of the steel sheet can be remarkably improved I got the knowledge that I can. Concretely, when the mass of the steel sheet is Wt and the total mass of Mn contained in the precipitate having a diameter exceeding 0.5 占 퐉 is Wp, if Wp / Wt 占 100? 0.01 is satisfied, the corrosion resistance of the steel sheet is greatly improved , A steel sheet excellent in the corrosion resistance of the cutting section was obtained. The corrosion resistance can be dramatically improved while the steel sheet is made high in strength by suppressing the amount of Mn contained in the precipitate having a diameter of more than 0.5 mu m to not more than 100 mass ppm by setting the Mn content to 0.16% It was found that the generation of rust in the cut section under the indoor environment can be greatly suppressed.
The present inventors have also studied a means for suppressing the amount of Mn contained in a precipitate having a diameter exceeding 0.5 mu m to 100 mass ppm or less for a steel sheet containing 0.16% by mass or more of Mn by mass%.
A steel sheet to be used as a product member of household appliances or office equipment is generally manufactured by reheating a hot rolled sheet and subjecting the hot rolled sheet to a hot rolled sheet to pick up the hot rolled sheet, A cold-rolled steel sheet is produced by subjecting a cold-rolled steel sheet to a continuous annealing treatment and, if necessary, temper rolling. Here, usually, a Mn-based sulfide is precipitated in the cast steel. When the reheating temperature of the cast steel is low, the Mn-based sulfide can not be dissolved at the reheating time, and the Mn-based sulfide precipitated in the cast steel remains on the steel sheet after the continuous annealing. On the other hand, when the reheating temperature of the cast steel is sufficiently high, the Mn-based sulfide dissolves during the reheating, but the Mn-based sulfide re-precipitates during the subsequent annealing.
The inventors of the present invention compared the amount of Mn contained in the precipitate having a diameter exceeding 0.5 mu m with respect to the steel sheet in which the Mn-based sulfide precipitated in the slab remained and the steel sheet in which the Mn-based sulfide was re-precipitated at the time of continuous annealing. As a result, it was found that the amount of Mn contained in the precipitate having a diameter exceeding 0.5 mu m tended to be lower in the steel sheet in which the Mn-based sulfide precipitated in the slab remained than in the steel sheet in which the Mn-based sulfide was precipitated at the time of continuous annealing .
As a result of further investigation by the present inventors, it has been found that the content of the casting component including the impurity component is limited and the reheating temperature of the cast steel is set to be lower than usual at 1000 ° C or higher and 1100 ° C or lower, It is possible to obtain a steel sheet in which the amount of Mn contained in the precipitate having a diameter exceeding 0.5 mu m is suppressed to 100 mass ppm or less by optimizing the coiling temperature of the hot-rolled sheet and the annealing temperature of the cold-rolled sheet.
Further, it is not clear why the corrosion resistance of the steel sheet is remarkably improved by retaining Mn-based sulfide on the cast steel. However, the present inventors presume that the reason is as follows.
A considerable number of the Mn-based sulfides present in the cast steel contains FeS in a small amount and has a composition of (Mn · Fe) S. On the other hand, when (Mn · Fe) S is dissolved in the reheating of the cast steel, MnS is precipitated again by continuous annealing in a subsequent step. That is, the Mn-based sulfide to be re-precipitated at the time of continuous annealing has a composition of FeS-free and mainly MnS.
Here, since MnS increases an anode defect, it can become a starting point of rust. In addition, MnS is estimated that well melted, MnS 2 O → 2H + Mn (OH) 2 + H 2 S The reaction H 2 S that is generated by lowering the anode portion of the pH, promotes the dissolution of iron in the water. On the other hand, Mn (Mn · Fe) S in which MnS is solved with Fe is chemically inert and insoluble in water as much as Fe is solubilized, compared with MnS. From the above reasons, it is presumed that Mn-based sulfide (MnS) which is re-precipitated at the time of continuous annealing tends to become a starting point of rust generation, as compared with the Mn-based sulfide ((Mn · Fe) S) existing in the cast steel.
Further, the amount of Mn required to fix S in the steel is smaller as S in the steel precipitates in the form of (Mn 占)) S rather than precipitated in the form of MnS. Therefore, the steel sheet in which the Mn-based sulfide ((Mn · Fe) S) precipitated in the slab remained in the steel sheet after the re-precipitation of the Mn-based sulfide (MnS) during the continuous annealing, It is presumed that the amount of Mn contained is lowered.
Further, when the Mn-based sulfide ((Mn · Fe) S) is left to remain at the time of reheating of the cast steel, the amount of solid solution S and the amount of solid solution Mn in the cold rolled steel sheet obtained by cold rolling in the subsequent step can be reduced. It is therefore presumed that the Mn-based sulfide (MnS) precipitated at the time of continuous annealing of the cold-rolled sheet is suppressed, and the corrosion resistance of the steel sheet is improved. It has also been found that when the amount of Mn contained in the precipitate having a diameter exceeding 0.5 占 퐉 is suppressed to the above range, a remarkable decrease in the corrosion resistance of the steel sheet is not observed even if the Si content is increased to 4.0%.
The present invention has been completed on the basis of these findings after further examination. That is, the structure of the present invention is as follows.
P: 0.03% or less; S: 0.02% or less; Al: 0.003% or more and 0.06% or less; By weight and the balance of Fe and inevitable impurities and having a Mn content of not more than 100 ppm by mass contained in the precipitate having a diameter of more than 0.5 占 퐉.
[2] A steel sheet comprising as a surface treatment layer a zinc-based plated layer on one surface or both surfaces of a steel sheet, wherein the steel sheet contains, by mass%, C: 0.001 to 0.1%, Si: 0.5% By mass or less, 1.0% or less of P, 0.03% or less of P, 0.02% or less of S, 0.003% or more and 0.06% or less of Al and a balance of Fe and inevitable impurities. A steel sheet excellent in corrosion resistance at a cut section having an Mn content of 100 mass ppm or less.
[3] The steel sheet according to item [2], wherein the zinc-plated layer is a zinc-plated layer having a plating amount of 5 g / m 2 or more per one surface.
[4] The steel sheet according to the above-mentioned [3], wherein at least one coating layer of an inorganic coating layer, an organic coating layer, and an inorganic or organic composite coating layer is further provided on the surface of the zinc-
[5] A steel sheet having a coating film containing a sacrificial pigment as a surface treatment layer on one side or both sides of a steel sheet, wherein the steel sheet contains C: 0.001 to 0.1%, Si: 0.5 to 4.0% , Mn: not less than 0.16% and not more than 1.0%, P: not more than 0.03%, S: not more than 0.02%, Al: not less than 0.003% and not more than 0.06%, the balance being Fe and inevitable impurities, And the amount of Mn contained in the precipitate of more than 100 mass ppm is excellent.
[6] The steel sheet according to the above [5], wherein the coating film containing the sacrificial pigment is excellent in corrosion resistance at the cut section, which is a coating film having a coating amount of 10 g / m 2 or more per one side.
[7] The steel sheet according to the above [5] or [6], wherein the sacrificial pigment contains Zn and / or Al and is excellent in corrosion resistance at the cut section.
[8] The coating film according to any one of the above-mentioned [5] to [7], further comprising at least one coating layer selected from the inorganic coating layer, the organic coating layer and the inorganic / organic composite coating layer, Steel plate.
P: 0.03% or less, S: 0.02% or less, Al: 0.003% or more, 0.06% or less, Or less and the balance of Fe and inevitable impurities is reheated and retained in a temperature range of 1000 占 폚 or more and 1,100 占 폚 or less in a temperature range and then subjected to hot rolling in which the finishing rolling end temperature is not lower than the Ar 3 transformation point Rolled at a coiling temperature of 680 DEG C or lower to obtain a hot rolled sheet, pickling the hot rolled sheet, cold rolling at a rolling ratio of 60% or more and 90% or less to obtain a cold rolled sheet, Wherein continuous annealing is performed at an annealing temperature of 700 DEG C or more and 850 DEG C or less.
[10] The method for producing a surface treatment layer as set forth in [9] above, wherein the surface treatment is performed after the continuous annealing to form a surface treatment layer on one side or both sides of the steel sheet, , The surface treatment is performed by a zinc-based plating treatment, and the surface treatment layer is made to be a zinc-based plating layer. When the Si content of the cast steel exceeds 0.5% by mass, Wherein the surface treatment layer is a coating film containing a sacrificial pigment.
[11] The plating method according to the above [10], wherein the zinc-based plating treatment is a plating treatment in which the plating amount per one surface is 5 g / m 2 or more, and the coating treatment with the paint containing the sacrificial- Is 10 g / m < 2 > or more.
[12] A method for producing a coating film according to the above [10] or [11], wherein a coating layer of at least one of an inorganic coating layer, an organic coating layer and an inorganic / organic composite coating layer is formed on the surface of the surface treatment layer, ≪ / RTI >
Industrial Applicability According to the present invention, even when a high-strength steel sheet is subjected to surface treatment such as zinc plating and then subjected to mechanical cutting, the surface of the steel sheet is subjected to surface treatment such as shearing, It is possible to sufficiently secure the corrosion resistance of the substrate. Therefore, according to the present invention, it is possible to suppress the generation of rust on the cutting edge, which has been a problem in reusing the high-strength steel sheet. Therefore, by applying the present invention mainly to electric appliances and office equipment used indoors, it is possible to easily reuse (reuse) the product member in addition to intensifying the strength of the product member.
Hereinafter, the present invention will be described in detail.
First, the composition of the inventive steel sheet and the reason for limiting the precipitates will be described. The element of the steel component specified in the present invention may be a factor of deterioration of the corrosion resistance at the cut section of the steel sheet. The percentages representing the following compositional proportions are by mass unless otherwise specified.
C: not less than 0.001% and not more than 0.1%
If the C content exceeds 0.1%, the hardness and deterioration of the ductility of the steel sheet become a problem. On the other hand, if the C content is less than 0.001%, the steel sheet becomes excessively soft and troubles such as burrs tend to occur at the time of cutting. Therefore, the C content is set to 0.001% or more and 0.1% or less. It is preferably not less than 0.001% and not more than 0.05%.
Si: 4.0% or less
Si is a solid solution strengthening element and contributes to the enhancement of the strength of the steel sheet. However, in the case of a content exceeding 4.0%, precipitates typified by SiO 2 , which is a starting point of corrosion, increase and the corrosion resistance is remarkably lowered. Therefore, the Si content is 4.0% or less. It is preferable that the lower limit is an inevitable impurity level (about 0.01%). From the viewpoint of plating ability, it is preferable to be limited to 0.5% or less, more preferably 0.1% or less, further preferably 0.05% or less from the viewpoint of corrosion resistance.
Mn: 0.16% or more and 1.0% or less
Mn is an element effective for suppressing the brittleness due to S during hot rolling of cast steel. Mn is an element for solid solution strengthening and is effective for increasing the strength of the steel sheet. In order to obtain a steel sheet strength exceeding a tensile strength (TS) of 440 MPa, it is necessary to set the Mn content to 0.16% or more. On the other hand, when the Mn content exceeds 1.0%, MnS precipitates during continuous casting of the steel to accelerate hot brittleness, resulting in slab cracking. When the Mn content exceeds 1.0%, the corrosion resistance of the steel sheet deteriorates. Therefore, the Mn content should be 0.16% or more and 1.0% or less. And preferably 0.16% or more and 0.5% or less.
P: not more than 0.03%
P is an element which is inevitably contained, and corrosion resistance of the steel sheet deteriorates as the content thereof increases. Therefore, the content of P is 0.03% or less.
S: not more than 0.02%
S is an element which is inevitably contained, and is a harmful element which causes red hot brittleness during hot rolling of cast steel. Further, S precipitates as MnS during the continuous casting of the steel to accelerate hot brittleness and cause slab cracking. Therefore, the S content is preferably reduced as much as possible, and it is set to 0.02% or less. It is preferably not more than 0.01%.
Al: not less than 0.003% and not more than 0.06%
Al is an element necessary for deoxidation of steelmaking, and the content thereof is 0.003% or more. On the other hand, if the Al content is excessively high, inclusions increase and surface defects of the steel sheet are liable to occur. Therefore, the Al content should be 0.06% or less.
The above is the basic component of the steel sheet of the present invention. Further, the steel sheet of the present invention may contain Nb, Ti, B, V, or the like as a selective element, for example, for the purpose of improving workability and the like.
In the present invention, the components other than the above (the remainder) are Fe and inevitable impurities. As the inevitable impurities, Sn, Sb, Ca, Zr and the like can be exemplified, and if the content is 2% or less in total, it is acceptable.
The steel sheet of the present invention is a steel sheet having the above composition and further containing Mn in an amount of 100 mass ppm or less contained in a precipitate having a diameter of more than 0.5 mu m among the precipitates present in the steel sheet.
Mn content in a precipitate having a diameter of more than 0.5 占 퐉: not more than 100 mass ppm
As described above, when the amount of Mn contained in the precipitate having a diameter of more than 0.5 mu m among the precipitates present in the steel sheet exceeds 100 mass ppm, the corrosion resistance of the steel sheet is remarkably deteriorated. Therefore, the amount of Mn contained in the precipitate having a diameter of more than 0.5 mu m is set to 100 mass ppm or less. Preferably 90 mass ppm or less. Among the precipitates present in the steel sheet of the present invention, the precipitates containing Mn mainly have a composition of (Mn · Fe) S, but MnS may be mixed to some extent.
The amount of Mn contained in the precipitate having a diameter of more than 0.5 mu m can be measured and calculated by, for example, the method of the later-described example.
By specifying the composition and the form of the precipitate as described above, a steel sheet having high strength and excellent corrosion resistance can be obtained. Therefore, according to the present invention, even when a high-strength steel sheet is subjected to surface treatment such as zinc plating and then mechanical cutting, the surface treatment layer, such as a shear section or a tread surface, The corrosion resistance of the cut surface can be sufficiently secured.
In order to improve the corrosion resistance, it is preferable to apply a surface treatment having a sacrificial mode action to one side or both sides of the inventive steel sheet. When the Si content of the steel sheet is 0.5% or less, the zinc-based plating layer is subjected to a zinc-based plating treatment, and when the Si content of the steel sheet exceeds 0.5%, the surface treatment having a sacrificial corrosion- It is preferable to form a coating film having a sacrificial mode action by applying a paint containing a pigment (sacrificial pigment), but needless to say, it is not limited thereto.
When the zinc plated layer is formed on one surface or both surfaces of the steel sheet of the present invention, it is preferable that the adhesion amount of the zinc plated layer is 5 g / m < 2 > or more per one surface from the viewpoint of sufficiently securing the sacrificial corrosion resistance of zinc. More preferably 10 g / m < 2 > or more. In addition, the upper limit of the deposition amount need not be specially determined, but may be suitably set from a manufacturing constraint. The kind of plating is not particularly limited, and it is applicable to all of hot-dip plating, electroplating, vapor deposition plating, and the like. The plating metal may be a multi-element system or an alloy plating system such as a Zn-Al system, a Zn-Ni system, a Zn-Cr system, a Zn-Fe system, or a Zn-Al-Mg system.
Further, for example, a chromate treatment layer, a phosphate treatment layer, a silane treatment layer, or the like may be formed on the surface of the above-mentioned plating layer. These layers are used for improving the adhesion to the coating in the case of using the steel sheet as a non-coated steel sheet for countermeasures against red rust (improvement in corrosion resistance) and for coating the steel sheet with coating or the like, It is effective to improve the corrosion resistance in the case of the present invention. These layers are also effective in improving characteristics other than corrosion resistance, for example, weatherability and the like.
When a coating film containing a sacrificial type pigment is formed on one side or both sides of the steel sheet of the present invention in place of the zinc-based plated layer, the adhesion amount of the coating film containing the sacrificial type pigment is preferably , And 10 g / m < 2 > or more per one side. More preferably 20 g / m < 2 > or more. In addition, the upper limit of the deposition amount need not be specially determined, but may be suitably set from a manufacturing constraint. The term " coating film containing a sacrificial pigment " as used herein means a coating film containing at least one of Zn, Al having a sacrificial action on iron, for example, an epoxy coating, an acrylic coating or a phenol coating, Refers to a coating film formed by a painting process using a paint to which a pigment (sacrificial type pigment) containing more than one species is added. Examples of the sacrificial pigment include Zn powder and Al powder. The addition amount of the sacrificial type pigment is preferably 10 to 80% by mass with respect to the total amount of the coating film. If the addition amount is 10% or more, the effect of the sacrificial method is recognized. On the other hand, if it is 80% or less, the sacrificial type pigment tends to be dispersed in the paint and does not settled well, so that coating does not become difficult.
One or more coating layers of an inorganic coating layer, an organic coating layer, and an inorganic or organic composite coating layer may be formed on one surface or both surfaces of the steel sheet according to the present invention after the surface treatment layer is formed. An inorganic coating layers are, for example, there may be mentioned SiO 2, TiN or the like. The organic coating layer includes, for example, an organic coating layer containing an acrylic resin, an epoxy resin, a polyester resin, a polyolefin resin, a fluororesin, and a copolymer resin thereof. The inorganic-organic composite coating layer is a coating layer containing a combination of a resin component constituting the organic coating layer and an inorganic component constituting the inorganic coating layer. An inorganic coating layer, an organic coating layer, and an inorganic or organic composite coating layer may be formed. For example, the inorganic coating layer and the organic coating layer may be formed in this order. By forming these coating layers, the cross-sectional corrosion resistance of the steel sheet and the corrosion resistance of the steel sheet flat plate portion are further improved. Further, when these coating layers are formed, the effects other than the corrosion resistance, for example, the improvement in the weatherability can be obtained.
Further, even if any one coating layer of the inorganic coating layer, the organic coating layer, and the inorganic or organic composite coating layer is formed on the surface of the zinc-based plated layer after the treatment layer (chromate treatment layer, phosphate treatment layer, silane treatment layer or the like) do.
Next, a method of manufacturing the steel sheet of the present invention will be described.
In the method for producing a steel sheet of the present invention, the cast steel having the above composition is preferably cooled once to a temperature in the range of 300 ° C or lower, then reheated to maintain a crack in a temperature range of 1000 ° C or higher and 1100 ° C or lower, subjected to hot rolling to an exit temperature above the Ar 3 transformation point and the hot rolled sheet by winding on the winding temperature below 680 ℃, and then pickling the hot-rolled sheet, cold to rolling rate of 60% or more than 90% Rolling is performed to form a cold-rolled sheet, and the cold-rolled sheet is subjected to continuous annealing at an annealing temperature of 700 ° C or more and 850 ° C or less.
There is no particular limitation on the production method of the cast steel, and for example, any of the conventional casting methods such as continuous casting and the like can be applied to a molten steel having the above composition by a converter or the like. It is also possible to use a bar-breaking method or a thin slab continuous casting method.
In the present invention, the cast steel is once cooled and reheated. At this time, it is preferable to cool to a temperature range of 300 DEG C or less. Once the cast steel is cooled, a precipitate containing Mn precipitates on the cast steel. This precipitate is mainly a precipitate having a composition of (Mn · Fe) S.
Reheating temperature of cast steel: 1000 캜 to 1100 캜
In the present invention, the reheating temperature is set to a temperature range in which the precipitate (mainly (Mn · Fe) S) present in the slab is not dissolved. If the reheating temperature of the cast steel exceeds 1100 DEG C, the precipitates in the cast steel will be dissolved. As a result, MnS is precipitated at the time of continuous annealing in the subsequent step, and the corrosion resistance of the steel sheet is deteriorated. On the other hand, if the reheating temperature of the cast steel is less than 1000 캜, the rolling property is remarkably lowered, and the hot rolling is hindered. Therefore, the reheating temperature of the cast steel is set to 1000 ° C or more and 1100 ° C or less.
Following reheating and cracking of the cast steel, the cast steel is hot-rolled. Hot rolling generally consists of rough rolling and finish rolling, but the condition of rough rolling is not particularly limited. Further, for example, in the case of casting a slab (steel material) by a thin slab continuous casting method, rough rolling may be omitted. Finishing rolling is carried out under the following conditions.
Finish rolling finish temperature: Ar 3 transformation point or more
When the finish rolling finish temperature is less than the Ar 3 transformation point, the crystal grain diameter after rolling tends to become uneven. When the crystal grain diameters of the steel sheet become uneven, problems such as non-uniform deformation and roughness of the press surface occur when the steel sheet is press-formed by a member having a predetermined shape. Therefore, the finishing rolling finishing temperature should be at least the Ar 3 transformation point. Preferably, the Ar 3 transformation point + 5 ° C or higher. However, if the finishing rolling finish temperature is excessively high, it is preferable that the Ar 3 transformation point is +50 占 폚 or less because there is a risk of deterioration of the surface property due to the scale and lowering of the production efficiency.
Coiling temperature: 680 ℃ or less
If the coiling temperature exceeds 680 占 폚, the dissolution of the precipitate (mainly (Mn 占 Fe) S) present in the cast steel is promoted. As a result, MnS is precipitated at the time of continuous annealing in the subsequent step, and the corrosion resistance of the steel sheet is deteriorated. Therefore, the coiling temperature is set to 680 占 폚 or less. However, if the coiling temperature is too low, productivity may be lowered. Therefore, the coiling temperature is preferably 650 DEG C or higher.
Then, the hot rolled sheet obtained by winding at the above coiling temperature is pickled and then subjected to cold rolling to obtain a cold rolled sheet.
Rolling rate of cold rolling: 60% or more and 90% or less
If the rolling rate of the cold rolling is less than 60%, the grain diameter becomes large due to continuous annealing in the subsequent step, and the surface appearance of the steel sheet is deteriorated during press forming. On the other hand, if the rolling rate of the cold rolling exceeds 90%, the rolling load becomes large, so that rolling becomes difficult. Therefore, the rolling rate of the cold rolling is set to 60% or more and 90% or less. , Preferably not less than 70% and not more than 90%.
Subsequently, the cold-rolled sheet obtained by the above-mentioned cold rolling is passed through a continuous annealing line and is subjected to continuous annealing.
Annealing temperature of continuous annealing: 700 ° C or more and 850 ° C or less
In the present invention, continuous annealing is performed at a temperature range higher than the recrystallization temperature of the steel to recrystallize the processed structure to improve the workability of the steel sheet. When the annealing temperature is less than 700 캜, recrystallization of steel can not be promoted. As a result, the hard work structure remains on the steel sheet, and the press formability is deteriorated. On the other hand, if the annealing temperature exceeds 850 DEG C, the energy load becomes large and the production cost rises. Therefore, the annealing temperature of the continuous annealing is set to 700 ° C or more and 850 ° C or less. And preferably 720 DEG C or more and 830 DEG C or less.
When continuous annealing is carried out, it is preferable that the time for which the cold-rolled sheet stays at a temperature range of 700 DEG C or higher and 850 DEG C or lower is 300 s or higher and 2000 s or lower. If the residence time at the above-mentioned temperature range is 300 s or more, the unrecrystallized portion remains in the steel sheet structure, and the workability of the steel sheet does not become inferior. On the other hand, if the residence time at the above-mentioned temperature range is 2000 s or less, productivity will not be low.
After continuous annealing, temper rolling may be performed for the purpose of adjusting the shape and surface roughness of the steel sheet. The elongation percentage of the temper rolling is not specifically defined, but is usually preferably in the range of 0.3% or more and 2.0% or less.
The thickness of the steel sheet is not particularly limited, but may be appropriately selected depending on the purpose of the steel sheet in the range of 0.2 to 2 mm, for example.
As a result, even when a high-tensile steel sheet having a Mn content of 100 mass ppm or less contained in a precipitate having a diameter of more than 0.5 μm is subjected to mechanical cutting after surface treatment such as zinc plating, , A high tensile strength steel sheet can be obtained which can sufficiently secure the corrosion resistance of a cut section that does not have a sacrificial mode action such as zinc plating.
The method of applying the plating treatment to the steel sheet is not particularly limited, and it is applicable to all of the hot-dip plating treatment, the electroplating treatment, the vapor deposition plating treatment and the like. In addition, plating may be performed on only one side of the steel sheet, or both sides of the steel sheet may be subjected to a plating treatment. When zinc plating is applied to the steel sheet, it is preferable that the adhesion amount per side of the zinc-based plated layer is 5 g / m 2 or more. The plating metal may be a multi-element system or an alloy plating system such as a Zn-Al system, a Zn-Ni system, a Zn-Cr system, a Zn-Fe system, or a Zn-Al-Mg system.
In addition, as a method of applying a paint containing a sacrificial pigment to the steel sheet as a surface treatment instead of a plating treatment, a method of applying a paint containing a sacrificial pigment is applied It is possible. For example, pigments (sacrificial pigments) containing at least one of Zn and Al having sacrificial action against iron are added to epoxy-based paints, acrylic-based paints and phenol-based paints, A method of coating the steel sheet on one side or both sides of the steel sheet using a coating means can be exemplified. It is preferable to adjust the adhesion amount per side to be not less than 10 g / m < 2 > so that the sacrificial mode action can be sufficiently exhibited.
After the surface treatment such as plating treatment is performed as described above to form a surface treatment layer such as a plating layer on the surface of the steel sheet or after further performing a chromate treatment, a phosphate treatment, a silane treatment or the like, the surface treatment layer At least one of an inorganic coating layer, an organic coating layer, and an inorganic or organic composite coating layer may be formed on the surface. For example, any one of an inorganic coating layer, an organic coating layer and an inorganic or organic composite coating layer may be formed, or an inorganic coating layer and an organic coating layer may be formed in this order. As a method of forming the inorganic coating layer, for example, electrodeposition coating, reduction precipitation and the like can be used. As a method of forming the organic coating layer and the inorganic-organic composite coating layer, for example, painting, laminating (film sticking) or the like can be used.
Example
The molten steel was melted in a converter, and the molten steel was cast by a continuous casting method. The cast steel contained the chemical components shown in Table 1, and the balance was composed of Fe and inevitable impurities. The cast steel which had been cooled to room temperature was reheated and subjected to hot rolling. After completion of the hot rolling, the cast steel was cooled and cooled to obtain a hot-rolled steel sheet. Then, the hot rolled sheet was pickled, cold rolled to form a cold rolled sheet, the cold rolled sheet was subjected to continuous annealing, and further subjected to temper rolling to form a steel sheet. The reheating temperature of the cast steel, the finish rolling finish temperature of the hot rolling, the coiling temperature, the rolling rate of the cold rolling, the annealing temperature of the continuous annealing, the annealing time (the holding time of the cold rolling plate at the annealing temperature) The sheet thickness of the steel sheet is shown in Table 2.
A specimen having a length of 50 mm and a width of 30 mm was sampled from the plate width central portion of each steel sheet obtained above and immersed in a 10% acetylacetone electrolyte solution of a non-aqueous system and subjected to constant current electrolysis at a current value of 20 mA / . The obtained solution was passed through a filter having a pore diameter of 0.5 mu m, and a precipitate having a diameter exceeding 0.5 mu m remained on the filter was collected. The collected precipitate was ashed and mixed with sodium carbonate: sodium tetraborate = 2: 1 (mass ratio), heated and melted in the form of glass. After melting, the resultant was again dissolved in a solution of HCl: water = 1: 1 (by mass ratio) to form a solution, and Mn was quantitatively analyzed by an ICP emission spectrometer to determine the mass of Mn contained in the precipitate having a diameter of more than 0.5 μm Wp). The amount of Mn (Wp / Wt 占106 , unit: mass ppm) contained in the precipitate having a diameter exceeding 0.5 占 퐉 was calculated from the mass Wp of the thus obtained Mn and the mass Wt of the dissolved sample. These results are shown in Table 2.
JIS No. 5 tensile test specimen (JIS Z 2201 (2009)) was taken from each steel sheet obtained in the above manner in a direction perpendicular to the rolling direction, and subjected to a tensile test according to JIS Z 2241 (2011) , And tensile strength (TS) were measured. These results are shown in Table 2.
Further, surface treatment (both surfaces) of each steel sheet obtained by the above was subjected to surface treatment. Table 3 shows the surface treatment method. The surface treatment was changed according to the Si content of the steel sheet. When the Si content of the steel sheet was 0.5% or less, plating treatment was performed, and when the Si content of the steel sheet was more than 0.5%, the coating treatment was performed. Steel No. 9 had a Si content of more than 0.5% but was plated. Although not plated, corrosion test of the cut section was carried out.
The obtained surface-treated steel sheet was sheared by a shearing machine and samples having a length of 50 mm and a width of 50 mm were collected from the center of the plate width. The dry and wet repetitive test was carried out using a sample having a cut end face (shear end face) collected by shearing. The test conditions of the dry and wet repetitive test are as follows: a sample is kept at 32 ° C and 60% relative humidity for 5 minutes by a wet tester, and then the sample is kept at a temperature of 20 ° C and a relative humidity of 35% for 30 minutes Was repeated for 10 cycles.
After the dry and wet repetitive test, the appearance of the cut end face (shear end face) of the sample was visually observed, and the corrosion resistance of the cut end face was evaluated by a three-step evaluation method. The case where the rust occurrence area ratio of the cut surface was 10% or less was evaluated as " corrosion resistance of the cut surface: very good (?) &Quot;. The rust occurrence area ratio of the cut section exceeding 10% and not more than 40% was evaluated as " good (?) &Quot; On the other hand, the case where the rust occurrence area ratio of the cut section exceeded 40% was evaluated as " corrosion resistance of the cut section: poor (x) ". These results are shown in Table 2.
As shown in Table 2, all of the steel sheets of the comparative examples did not have sufficient cross-sectional corrosion resistance. On the other hand, all of the steel sheets of the inventive example exhibit good tensile strength (TS) of more than 440 MPa and excellent cross-sectional corrosion resistance even though they contain 0.16% or more Mn which causes deterioration of corrosion resistance.
INDUSTRIAL APPLICABILITY As described above, according to the present invention, even when the Mn content is set to 0.16% or more for the purpose of increasing the strength, a steel sheet excellent in the corrosion resistance of the cut section can be obtained. Therefore, when a steel sheet (surface-treated steel sheet) subjected to a surface treatment such as a plating treatment on the steel sheet of the present invention is actually applied to strength members such as household appliances and office equipment, excellent cross-sectional corrosion resistance is exhibited and members can be reused.
Claims (12)
C: not less than 0.001% and not more than 0.1%, Si: not less than 0.01% and not more than 4.0%
Mn: 0.16% to 1.0%, P: 0.03% or less,
S: not more than 0.02%, Al: not less than 0.003% and not more than 0.06%
And a balance of Fe and inevitable impurities, and having a Mn content of not more than 100 mass ppm in a precipitate having a diameter of more than 0.5 mu m, and having a strength of more than 440 MPa, This excellent steel plate.
C: not less than 0.001% and not more than 0.1%, Si: not less than 0.01% and not more than 0.5%
Mn: 0.16% to 1.0%, P: 0.03% or less,
S: not more than 0.02%, Al: not less than 0.003% and not more than 0.06%
And a balance of Fe and inevitable impurities, and having a Mn content of not more than 100 mass ppm in a precipitate having a diameter of more than 0.5 mu m, and having a strength of more than 440 MPa, This excellent steel plate.
Wherein the zinc-based plated layer is a zinc-based plated layer having a plating amount of 5 g / m < 2 > or more per one side.
Wherein at least one coating layer of an inorganic coating layer, an organic coating layer, and an inorganic-organic composite coating layer is further provided on the surface of the zinc-based plated layer.
C: not less than 0.001% and not more than 0.1%, Si: not less than 0.5% and not more than 4.0%
Mn: 0.16% to 1.0%, P: 0.03% or less,
S: not more than 0.02%, Al: not less than 0.003% and not more than 0.06%
And a balance of Fe and inevitable impurities, and having a Mn content of not more than 100 mass ppm in a precipitate having a diameter of more than 0.5 mu m, and having a strength of more than 440 MPa, This excellent steel plate.
Wherein the coating film containing the sacrificial pigment is a coating film having an adhesion amount per one side of not less than 10 g / m < 2 >.
Wherein the sacrificial type pigment contains Zn and / or Al.
Wherein at least one coating layer of an inorganic coating layer, an organic coating layer and an inorganic or organic composite coating layer is further provided on the surface of the coating film containing the sacrificial pigment.
C: not less than 0.001% and not more than 0.1%, Si: not less than 0.01% and not more than 4.0%
Mn: 0.16% to 1.0%, P: 0.03% or less,
S: not more than 0.02%, Al: not less than 0.003% and not more than 0.06%
The contained, and the balance being Fe and inevitable by impurities cast steel having a composition consisting of, re-heated to maintain cracks in a temperature range of less than 1000 ℃ 1100 ℃ then hot to a finish rolling temperature above the Ar 3 transformation point rolling conducted And rolled at a coiling temperature of 650 ° C or higher and 680 ° C or lower to obtain a hot rolled sheet, pickling the hot rolled sheet, and then cold rolling at a rolling ratio of 60% or more and 90% or less to obtain a cold rolled sheet, A method for producing a steel sheet having a strength exceeding 440 MPa as defined in claim 1, characterized in that the cold-rolled sheet is subjected to continuous annealing at an annealing temperature of 700 ° C or more and 850 ° C or less.
In the case where the Si content of the cast steel is 0.5% by mass or less in the case of performing the surface treatment after the continuous annealing and forming the surface treatment layer on one side or both sides of the steel sheet, The surface treatment layer is formed into a zinc-based plated layer by plating,
Characterized in that when the Si content of the cast steel is more than 0.5% by mass, the surface treatment is performed by a paint containing a sacrificial pigment, and the surface treatment layer is a coating film containing a sacrificial pigment Of the steel sheet.
Wherein the zinc-based plating treatment is a plating treatment in which an amount of deposition of plating per one surface is not less than 5 g /
Wherein the coating treatment with the paint containing the sacrificial pigment is a coating treatment in which the adhesion amount per one side is not less than 10 g / m < 2 >.
Wherein at least one coating layer of an inorganic coating layer, an organic coating layer, and an inorganic or organic composite coating layer is formed on the surface of the surface treatment layer.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JPJP-P-2013-158468 | 2013-07-31 | ||
| JP2013158468 | 2013-07-31 | ||
| PCT/JP2014/003776 WO2015015740A1 (en) | 2013-07-31 | 2014-07-16 | Steel sheet with excellent cut edge corrosion resistance and manufacturing method therefor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| KR20160003098A KR20160003098A (en) | 2016-01-08 |
| KR101771337B1 true KR101771337B1 (en) | 2017-08-24 |
Family
ID=52431303
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| KR1020157033582A KR101771337B1 (en) | 2013-07-31 | 2014-07-16 | Steel sheet with excellent corrosion resistance at cut end surface and method for manufacturing the same |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JP6065884B2 (en) |
| KR (1) | KR101771337B1 (en) |
| CN (1) | CN105452508B (en) |
| WO (1) | WO2015015740A1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6972722B2 (en) * | 2017-07-18 | 2021-11-24 | 日本製鉄株式会社 | Low alloy steel |
| CN109425319B (en) * | 2017-08-25 | 2020-06-23 | 宝山钢铁股份有限公司 | Method for detecting influence degree of pickling process on transverse section |
| CN111684095B (en) * | 2018-02-01 | 2021-12-10 | 住友电气工业株式会社 | Copper-clad steel wire and canted coil spring |
| KR102490927B1 (en) * | 2020-12-21 | 2023-01-26 | 주식회사 포스코 | Plated steel sheet for exterior panel, and method for manufacturing the same |
| CN115445892A (en) * | 2022-10-21 | 2022-12-09 | 乔冠应用材料(淮安)有限公司 | Anticorrosion treatment process for copper material strip coil cutting surface |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010126764A (en) * | 2008-11-27 | 2010-06-10 | Kobe Steel Ltd | Chromate-free chemically converted galvanized steel sheet having excellent corrosion resistance at cut edge face |
| JP2011144414A (en) * | 2010-01-13 | 2011-07-28 | Sumitomo Metal Ind Ltd | Cold rolled steel sheet and method for producing the same |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10330883A (en) * | 1997-04-03 | 1998-12-15 | Kawasaki Steel Corp | Surface treated steel sheet excellent in end-face rusting resistance |
| JP3319385B2 (en) * | 1998-04-20 | 2002-08-26 | 日本鋼管株式会社 | Painted galvanized steel sheet excellent in workability, scratch resistance and corrosion resistance and method for producing the same |
| JP4311019B2 (en) | 2003-01-10 | 2009-08-12 | Ｊｆｅスチール株式会社 | Surface-treated steel sheet with excellent corrosion resistance on the cut end face |
| JP4119832B2 (en) * | 2003-12-24 | 2008-07-16 | 新日本製鐵株式会社 | High strength steel plate for automobile fuel tank with excellent press formability, corrosion resistance and secondary workability, and method for producing the same |
| JP5549307B2 (en) * | 2009-04-13 | 2014-07-16 | Ｊｆｅスチール株式会社 | Cold-rolled steel sheet excellent in aging and bake hardenability and method for producing the same |
| JP5521520B2 (en) * | 2009-12-03 | 2014-06-18 | 新日鐵住金株式会社 | Alloyed hot-dip galvanized steel sheet and method for producing the same |
| JP5397263B2 (en) | 2010-02-23 | 2014-01-22 | Ｊｆｅスチール株式会社 | High tensile cold-rolled steel sheet and method for producing the same |
| EP2578719B1 (en) * | 2010-05-31 | 2019-05-01 | Nippon Steel & Sumitomo Metal Corporation | Hot-dip aluminum alloy plated steel having excellent shear cut edge corrosion resistance and processed part corrosion resistance, and method of manufacturing the same |
| CN103074546B (en) * | 2011-10-25 | 2014-12-10 | 上海梅山钢铁股份有限公司 | Cold-rolled strip steel for condenser tube of refrigerator and manufacturing method thereof |
-
2014
- 2014-07-15 JP JP2014144714A patent/JP6065884B2/en active Active
- 2014-07-16 KR KR1020157033582A patent/KR101771337B1/en active IP Right Grant
- 2014-07-16 WO PCT/JP2014/003776 patent/WO2015015740A1/en active Application Filing
- 2014-07-16 CN CN201480043485.0A patent/CN105452508B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010126764A (en) * | 2008-11-27 | 2010-06-10 | Kobe Steel Ltd | Chromate-free chemically converted galvanized steel sheet having excellent corrosion resistance at cut edge face |
| JP2011144414A (en) * | 2010-01-13 | 2011-07-28 | Sumitomo Metal Ind Ltd | Cold rolled steel sheet and method for producing the same |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2015015740A1 (en) | 2015-02-05 |
| CN105452508A (en) | 2016-03-30 |
| KR20160003098A (en) | 2016-01-08 |
| JP6065884B2 (en) | 2017-01-25 |
| JP2015045086A (en) | 2015-03-12 |
| CN105452508B (en) | 2018-10-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR101445813B1 (en) | HIGH-STRENGTH STEEL SHEET HAVING EXCELLENT HYDROGEN EMBRITTLEMENT RESISTANCE AND MAXIMUM TENSILE STRENGTH OF 900 MPa OR MORE, AND PROCESS FOR PRODUCTION THEREOF | |
| JP5650222B2 (en) | Method of manufacturing a steel member with a metal coating that provides protection against corrosion, and steel member | |
| KR101604965B1 (en) | High-strength steel plate and manufacturing method thereof | |
| WO2013047820A1 (en) | Hot-dip galvanized steel sheet and process for producing same | |
| EP2762590A1 (en) | Galvanized steel sheet and method of manufacturing same | |
| KR101668638B1 (en) | Hot-dip galvannealed steel sheet | |
| KR101771337B1 (en) | Steel sheet with excellent corrosion resistance at cut end surface and method for manufacturing the same | |
| CN111386358A (en) | High-strength galvanized steel sheet and method for producing same | |
| KR101657866B1 (en) | High strength galvanized steel sheet and method for manufacturing the same | |
| CN112930411B (en) | High yield ratio and high strength galvanized steel sheet and method for producing same | |
| KR20180095698A (en) | High Yield High Strength Galvanized Steel Sheet and Method for Manufacturing the Same | |
| JP6402830B2 (en) | Alloyed hot-dip galvanized steel sheet and method for producing the same | |
| CN108603262B (en) | High yield ratio type high strength galvanized steel sheet and method for producing same | |
| KR101688285B1 (en) | Galvannealed steel sheet | |
| US20210324504A1 (en) | High-ductility, high-strength electrolytic zinc-based coated steel sheet and method for producing the same | |
| KR101358567B1 (en) | High-strength hot-dip zinc-coated steel sheet having excellent surface appearance and process for production of same | |
| JP4940813B2 (en) | Method for producing hot-dip galvanized steel sheet having a value of TS × El of 21000 MPa ·% or more | |
| KR101657843B1 (en) | Zn ALLOY PLATED STEEL SHEET HAVING EXCELLENT WELDABILITY AND PROCESSED PART CORROSION RESISTANCE AND METHOD FOR MANUFACTURING THE SAME | |
| US20170349978A1 (en) | Aluminum alloy sheet | |
| KR101736640B1 (en) | Hot dip zinc alloy coated steel sheet having excellent coatability and spot weldability and method for manufacturing same | |
| JP5625442B2 (en) | High-strength steel sheet with a tensile strength of 1180 MPa or more with excellent delayed fracture resistance | |
| EP3778980A1 (en) | High-strength alloyed hot-dip galvanized steel sheet and manufacturing method therefor | |
| TWI546390B (en) | Steel sheet, hot dip galvanizing steel sheet, galvannealed steel sheet, and method for manufacturing thereof | |
| CN110945160A (en) | High-strength cold-rolled steel sheet and method for producing same | |
| JP7302756B1 (en) | Steel plate for hot press, manufacturing method thereof, hot press member and manufacturing method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A201 | Request for examination | ||
| E902 | Notification of reason for refusal | ||
| E701 | Decision to grant or registration of patent right | ||
| GRNT | Written decision to grant |