US20190270127A1 - Method for manufacturing hot-rolled coil, and method for shape-correction of hot-rolled coil - Google Patents
Method for manufacturing hot-rolled coil, and method for shape-correction of hot-rolled coil Download PDFInfo
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- US20190270127A1 US20190270127A1 US16/319,254 US201716319254A US2019270127A1 US 20190270127 A1 US20190270127 A1 US 20190270127A1 US 201716319254 A US201716319254 A US 201716319254A US 2019270127 A1 US2019270127 A1 US 2019270127A1
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- hot
- rolled coil
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- 238000000034 method Methods 0.000 title claims abstract description 58
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 28
- 238000012937 correction Methods 0.000 title description 22
- 239000011572 manganese Substances 0.000 claims abstract description 64
- 239000010936 titanium Substances 0.000 claims abstract description 60
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 58
- 239000010959 steel Substances 0.000 claims abstract description 58
- 239000011651 chromium Substances 0.000 claims abstract description 57
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 36
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 34
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims abstract description 33
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims abstract description 31
- 229910052719 titanium Inorganic materials 0.000 claims abstract description 31
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 30
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims abstract description 30
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 30
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 30
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 30
- 239000010703 silicon Substances 0.000 claims abstract description 30
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims abstract description 29
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims abstract description 29
- 229910052796 boron Inorganic materials 0.000 claims abstract description 29
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 29
- 239000011574 phosphorus Substances 0.000 claims abstract description 29
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims abstract description 28
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 28
- 239000011593 sulfur Substances 0.000 claims abstract description 28
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 27
- 238000001816 cooling Methods 0.000 claims abstract description 27
- 239000012535 impurity Substances 0.000 claims abstract description 26
- 238000005098 hot rolling Methods 0.000 claims abstract description 13
- 238000003303 reheating Methods 0.000 claims abstract description 13
- 230000007547 defect Effects 0.000 description 23
- 230000000052 comparative effect Effects 0.000 description 20
- 230000009466 transformation Effects 0.000 description 17
- 230000000694 effects Effects 0.000 description 13
- 239000000463 material Substances 0.000 description 12
- 229910000859 α-Fe Inorganic materials 0.000 description 7
- 230000001965 increasing effect Effects 0.000 description 6
- 238000005275 alloying Methods 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 230000000704 physical effect Effects 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 3
- 229910001566 austenite Inorganic materials 0.000 description 3
- 230000006866 deterioration Effects 0.000 description 3
- 230000005484 gravity Effects 0.000 description 3
- 239000006104 solid solution Substances 0.000 description 3
- 238000005728 strengthening Methods 0.000 description 3
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 2
- 230000002411 adverse Effects 0.000 description 2
- 230000004075 alteration Effects 0.000 description 2
- 229910001563 bainite Inorganic materials 0.000 description 2
- 239000003575 carbonaceous material Substances 0.000 description 2
- 230000001747 exhibiting effect Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 229910052750 molybdenum Inorganic materials 0.000 description 2
- 239000011733 molybdenum Substances 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 238000005204 segregation Methods 0.000 description 2
- 238000010583 slow cooling Methods 0.000 description 2
- 241000219307 Atriplex rosea Species 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 229910001567 cementite Inorganic materials 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000005097 cold rolling Methods 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- KSOKAHYVTMZFBJ-UHFFFAOYSA-N iron;methane Chemical compound C.[Fe].[Fe].[Fe] KSOKAHYVTMZFBJ-UHFFFAOYSA-N 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910001562 pearlite Inorganic materials 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 239000011573 trace mineral Substances 0.000 description 1
- 235000013619 trace mineral Nutrition 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Images
Classifications
-
- 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
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
-
- 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
-
- 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
- B21B3/02—Rolling special iron alloys, e.g. stainless steel
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0226—Hot rolling
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0247—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
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
-
- 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
- C22C38/02—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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium 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
- C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/32—Ferrous alloys, e.g. steel alloys containing chromium with boron
-
- 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
- B21B2001/225—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 by hot-rolling
Definitions
- the present invention relates to a method for manufacturing a hot-rolled coil and a method for correcting the shape of a hot-rolled coil. More specifically, the present invention relates to a method for manufacturing a hot-rolled coil for preventing shape defects, which may prevent shape defects from being caused by self-weight during manufacturing of the hot-rolled coil, and to a method for correcting the shape of a hot-rolled coil.
- One embodiment of the present invention is intended to provide a method for manufacturing a hot-rolled coil, which has an excellent effect of preventing the deformation of the hot-rolled coil.
- Another embodiment of the present invention is intended to provide a method for correcting the shape of a hot-rolled coil, which may prevent deterioration in the material and physical properties of the hot-rolled coil.
- Still another embodiment of the present invention is intended to provide a method for correcting the shape of a hot-rolled coil, which may prevent surface defects of the hot-rolled coil from occurring when correcting the shape by application of an external force.
- Yet another embodiment of the present invention is intended to provide a method for correcting the shape of a hot-rolled coil, which has excellent economic efficiency.
- the method for manufacturing the hot-rolled coil includes the steps of: reheating a steel slab including 0.18 to 0.56 wt % carbon (C), 0.1 to 0.5 wt % silicon (Si), 0.7 to 6.5 wt % manganese (Mn), more than 0 but not more than 0.02 wt % phosphorus (P), more than 0 wt % but not more than 0.02 wt % sulfur (S), more than 0 wt % but not more than 0.3 wt % chromium (Cr), more than 0 wt % but not more than 0.004 wt % boron (B), 0.01 to 0.04 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities; hot-rolling the steel slab at a finishing mill delivery temperature of 850° C. to 950° C., thereby forming
- the steel slab may include 0.21 to 0.37 wt % carbon (C), 0.1 to 0.4 wt % silicon (Si), 1.1 to 1.5 wt % manganese (Mn), more than 0 wt % but not more than 0.02 wt % phosphorus (P), more than 0 wt % but not more than 0.02 wt % sulfur (S), 0.1 to 0.3 wt % chromium (Cr), 0.001 to 0.004 wt % boron (B), 0.01 to 0.04 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities.
- C carbon
- Si silicon
- Mn manganese
- P more than 0 wt % but not more than 0.02 wt % phosphorus
- S 0.1 to 0.3 wt % chromium (Cr)
- Cr 0.001 to 0.004 wt % boron
- Ti 0.01 to 0.
- the steel slab may include 0.18 to 0.25 wt % carbon, 0.3 to 0.5 wt % silicon (Si), 2 to 6.5 wt % manganese (Mn), more than 0 wt % but not more than 0.02 wt % phosphorus (P), more than 0 wt % but not more than 0.01 wt % sulfur (S), more than 0 wt % but not more than 0.1 wt % chromium (Cr), more than 0 wt % but not more than 0.001 wt % boron (B), 0.01 to 0.04 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities.
- the steel slab may include 0.5 to 0.56 wt % carbon (C), 0.1 to 0.3 wt % silicon (Si), 0.7 to 1 wt % manganese (Mn), more than 0 wt % but not more than 0.02 wt % phosphorus (P), more than 0 wt % but not more than 0.01 wt % sulfur (S), 0.1 to 0.3 wt % chromium (Cr), more than 0 wt % but not more than 0.001 wt % boron (B), 0.01 to 0.02 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities.
- C carbon
- Si silicon
- Mn manganese
- P manganese
- P manganese
- P more than 0 wt % but not more than 0.01 wt % sulfur
- Cr 0.1 to 0.3 wt % chromium
- B 0.01 to 0.02 w
- the method for correcting the shape of the hot-rolled coil includes the steps of: mounting the hot-rolled coil on a hanger forming the lower part of a C-hook; measuring the longest diameter of the hot-rolled coil using an outer diameter measuring means provided in the upper part of the C-hook; adjusting the longest diameter of the hot-rolled coil to be perpendicular to the C-hook by means of a driving roll provided on the hanger; and placing the C-hook, which has the hot-rolled coil mounted thereon, on a stand, followed by lifting, thereby correcting the shape of the hot-rolled coil by self-weight.
- Still another aspect of the present invention is directed to a method for correcting the shape of a hot-rolled coil.
- the method for correcting the shape of the hot-rolled coil includes the steps of: mounting the hot-rolled coil on a hanger forming the lower part of a C-hook; measuring the longest diameter of the hot-rolled coil using an outer diameter measuring means provided in the upper part of the C-hook; adjusting the longest diameter of the hot-rolled coil to be perpendicular to the C-hook by means of a driving roll provided on the lower hanger; and placing the C-hook, which has the hot-rolled coil mounted thereon, on a stand, followed by lifting, thereby correcting the shape of the hot-rolled coil by self-weight, wherein the hot-rolled coil is manufactured by a method including the steps of: reheating a steel slab including 0.18 to 0.56 wt % carbon (C), 0.1 to 0.5 wt % silicon (Si), 0.7 to 6.5 wt % manganese (Mn), more than 0
- the hot-rolled coil may include 0.21 to 0.37 wt % carbon (C), 0.1 to 0.4 wt % silicon (Si), 1.1 to 1.5 wt % manganese (Mn), more than 0 wt % but not more than 0.02 wt % phosphorus (P), more than 0 wt % but not more than 0.02 wt % sulfur (S), 0.1 to 0.3 wt % chromium (Cr), 0.001 to 0.004 wt % boron (B), 0.01 to 0.04 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities.
- C carbon
- Si silicon
- Mn manganese
- P more than 0 wt % but not more than 0.02 wt % phosphorus
- S 0.1 to 0.3 wt % chromium (Cr)
- Cr 0.001 to 0.004 wt % boron
- Ti 0.01
- the hot-rolled sheet may be cooled and coiled at a coiling temperature of 700° C. to 900° C.
- shape correction When shape correction is performed for a hot-rolled coil manufactured by the method for manufacturing the hot-rolled coil according to the present invention, it may delay the phase transformation of the steel during cooling after hot rolling, thereby preventing deterioration in the material and physical properties of the hot-rolled coil while exhibiting an excellent effect of preventing deformation of the hot-rolled coil.
- the use of correction by self-weight and gravity makes it possible to prevent surface defects (such as scratches) of the hot-rolled coil, which occur when correction by an external force is used.
- it may reduce the correction cost and provide excellent economic efficiency.
- FIG. 1 shows a method for manufacturing a hot-rolled coil according to one embodiment of the present invention.
- FIG. 2 shows a method for correcting the shape of a hot-rolled coil according to one embodiment of the present invention.
- FIG. 3 schematically shows a method for correcting the shape of a hot-rolled coil according to one embodiment of the present invention.
- FIG. 4( a ) is a photograph showing a hot-rolled coil according to one example of the present invention immediately after coiling
- FIG. 4( b ) is a photograph showing the hot-rolled coil after air cooling.
- FIG. 5( a ) is a photograph showing a hot-rolled coil according to another example of the present invention immediately after coiling
- FIG. 5( b ) is a photograph showing the hot-rolled coil after air cooling.
- FIG. 6( a ) is a photograph showing a hot-rolled coil of a comparative example for the present invention immediately after coiling
- FIG. 6( b ) is a photograph showing the hot-rolled coil after air cooling.
- FIG. 7 is a graph comparing the phase transformation curves of hot-rolled coils with the passage of hot-rolled coil manufacturing time and shape correction time in an example of the present invention and a comparative example for the present invention.
- FIG. 1 shows a method for manufacturing a hot-rolled coil according to one embodiment of the present invention.
- the method for manufacturing the hot-rolled coil includes the steps of: (S 10 ) reheating a steel slab; (S 20 ) hot rolling; and (S 30 ) coiling.
- the method for manufacturing the hot-rolled coil includes the steps of: (S 10 ) reheating a steel slab including 0.18 to 0.56 wt % carbon (C), 0.1 to 0.5 wt % silicon (Si), 0.7 to 6.5 wt % manganese (Mn), more than 0 wt % but not more than 0.02 wt % phosphorus (P), more than 0 wt % but not more than 0.02 wt % sulfur (S), more than 0 wt % but not more than 0.3 wt % chromium (Cr), more than 0 wt % but not more than 0.004 wt % boron (B), 0.01 to 0.04 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities; (S 20 ) hot-rolling the steel slab at a finishing mill delivery temperature of 850° C. to 950° C., thereby forming a hot-rolled sheet;
- This step is a step of reheating a steel slab including 0.18 to 0.56 wt % carbon (C), 0.1 to 0.5 wt % silicon (Si), 0.7 to 6.5 wt % manganese (Mn), more than 0 wt % but not more than 0.02 wt % phosphorus (P), more than 0 wt % but not more than 0.02 wt % sulfur (S), more than 0 wt % but not more than 0.3 wt % chromium (Cr), more than 0 wt % but not more than 0.004 wt % boron (B), 0.01 to 0.04 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities.
- C 0.18 to 0.56 wt % carbon
- Si 0.1 to 0.5 wt % silicon
- Mn manganese
- P more than 0 wt % but not more than 0.02 wt
- Carbon (C) is added to ensure strength. Carbon is contained in an amount of 0.18 to 0.56 wt % based on the total weight of the steel slab. If the content of carbon is less than 0.18 wt %, it may be difficult to ensure sufficient strength. On the other hand, if the content of carbon is more than 0.56 wt %, toughness may be reduced.
- Silicon (Si) functions as a deoxidizer for removing oxygen from the steel and is added for solid solution strengthening.
- silicon is contained in an amount of 0.1 to 0.5 wt % based on the total weight of the steel slab. If the content of silicon is less than 0.1 wt %, the effect of adding the same will be insufficient, and if the content of silicon is more than 0.5 wt %, it may reduce weldability and produce red scale during reheating and hot rolling, thus adversely affecting the surface quality. In addition, it may adversely affect the coating property after welding.
- Manganese (Mn) is a solid solution strengthening element which is effective in ensuring strength by increasing the hardenability of the steel.
- manganese is an austenite stabilizing element which contributes to ferrite grain refinement by delaying ferrite and pearlite transformation.
- manganese is contained in 0.7 to 6.5 wt % based on the total weight of the steel slab. If the content of manganese is less than 0.7 wt %, the solid solution strengthening effect may be insufficient. On the other hand, the content of manganese is more than 6.5 wt %, weldability may be greatly reduced. In addition, a problem may arise in that the ductility of the steel sheet is greatly reduced due to the formation of an MnS inclusion and the occurrence of central segregation.
- Phosphorus (P) is added to inhibit cementite formation and increase strength.
- phosphorus deteriorates weldability and causes a difference in final properties by slab center segregation.
- the content of phosphorus (P) is limited to more than 0 wt % but not more than 0.02 wt % based on the total weight of the steel slab.
- S is an element that reduces the toughness and weldability of the steel and binds to manganese to form a non-metallic inclusion (MnS) that causes cracks during processing of the steel. For this reason, the content of sulfur (S) is limited to more than 0 wt % but not more than 0.02 wt % based on the total weight of the steel slab.
- Chromium is added for the purpose of increasing the hardenability and strength of the steel.
- chromium is contained in an amount of more than 0 wt % but not more than 0.3 wt % based on the total weight of the steel slab. If the content of chromium is more than 0.3 wt %, the toughness of the hot-rolled coil may be reduced.
- Boron (B) is added for the purpose of compensating for hardenability by replacing the expensive hardening element molybdenum, and has the effect of refining grains by increasing the austenite grain growth temperature.
- boron is contained in an amount of more than 0 wt % but not more than 0.004 wt % based on the total weight of the steel slab. If boron is contained in an amount of more than 0.004 wt %, the risk of reducing elongation may increase.
- Titanium (Ti) is added for the purpose of enhancing hardenability and improving properties by precipitate formation. In addition, it effectively contributes to austenite grain refinement by forming precipitate phases such as Ti(C,N) at high temperature.
- titanium is contained in an amount of 0.01 to 0.04 wt % based on the total weight of the steel slab. If titanium is contained in an amount of less than 0.01 wt %, the effect of adding the same may be insufficient, and if titanium is contained in an amount of more than 0.04 wt %, continuous casting defects may occur, it may be difficult to ensure the physical properties of the hot-rolled coil, and cracks on the surface of the hot-rolled coil may occur.
- the remainder other than the above-described components is substantially composed of iron (Fe).
- the expression “remainder is substantially composed of iron (Fe)” means that one containing other trace elements, including inevitable impurities, may be included in the present invention, as long as it does not impair the effect of the present invention.
- the steel slab may be applied to a medium-carbon hot-rolled coil.
- the steel slab may include 0.21 to 0.37 wt % carbon (C), 0.1 to 0.4 wt % silicon (Si), 1.1 to 1.5 wt % manganese (Mn), more than 0 wt % but not more than 0.02 wt % phosphorus (P), more than 0 wt % but not more than 0.02 wt % sulfur (S), 0.1 to 0.3 wt % chromium (Cr), 0.001 to 0.004 wt % boron (B), 0.01 to 0.04 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities.
- the steel slab may be applied to a high-manganese hot-rolled coil.
- the steel slab may include 0.18 to 0.25 wt % carbon, 0.3 to 0.5 wt % silicon (Si), 2 to 6.5 wt % manganese (Mn), more than 0 wt % but not more than 0.02 wt % phosphorus (P), more than 0 wt % but not more than 0.01 wt % sulfur (S), more than 0 wt % but not more than 0.1 wt % chromium (Cr), more than 0 wt % but not more than 0.001 wt % boron (B), 0.01 to 0.04 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities.
- the steel slab may be applied to a high-carbon hot-rolled coil.
- the steel slab may include 0.5 to 0.56 wt % carbon (C), 0.1 to 0.3 wt % silicon (Si), 0.7 to 1 wt % manganese (Mn), more than 0 wt % but not more than 0.02 wt % phosphorus (P), more than 0 wt % but not more than 0.01 wt % sulfur (S), 0.1 to 0.3 wt % chromium (Cr), more than 0 wt % but not more than 0.001 wt % boron (B), 0.01 to 0.02 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities.
- the steel slab may be heated at a slab reheating temperature (SRT) of 1,150° C. to 1,250° C. At this slab reheating temperature, the effect of homogenizing the alloying elements may be excellent.
- SRT slab reheating temperature
- This step is a step of hot-rolling the steel slab at a finishing mill delivery temperature of 850° C. to 950° C., thereby forming a hot-rolled sheet.
- the hot-rolled coil may have both excellent rigidity and excellent moldability and is excellent in terms of coiling workability, and the effect of preventing deformation of the hot-rolled coil may be excellent.
- This step is a step of cooling the hot-rolled sheet, followed by coiling at a coiling temperature of 700° C. or higher.
- the hot-rolled sheet may be cooled to the coiling temperature and coiled at that temperature.
- the cooling may be performed by air cooling without using cooling water.
- the “bulging defects” may refer to shape distortion defects of the hot-rolled coil.
- the “bulging defects” may refer to shape distortion defects caused by the change of the inner and outer diameters of the hot-rolled coil to an ellipse rather than a circle, due to the distortion of the hot-rolled coil in the direction of gravity, among shape defects that occur on the hot-rolled coil.
- the control of cooling may be performed such that the coiling is completed at a temperature equal to or higher than a temperature at which phase transformation begins.
- ferrite phase transformation begins after a certain time after the coiling, and for this reason, the time taken for phase transformation to be completed may increase rapidly due to slow cooling (air cooling) of the coil after the coiling, thereby advantageously preventing shape deformation.
- one embodiment of the present invention may provide process conditions that delay the time point of occurrence of phase transformation after coiling as much as possible.
- phase transformation of the hot-rolled sheet may proceed in the cooling process, and additional phase transformation may occur after formation of the hot-rolled coil, resulting in an increase in the coil volume, and then the hot-rolled coil may shrink with lowering temperature and the shape thereof is deformed to an elliptical shape by self-weight, thus causing bulging defects.
- the hot-rolled sheet may be cooled and coiled at a coiling temperature of 700° C. to 900° C.
- the coiling may be performed at a coiling temperature of 730° C. to 820° C.
- the manufactured hot-rolled coil may include ferrite and bainite microstructures.
- FIG. 2 shows a method for correcting the shape of a hot-rolled coil according to one embodiment of the present invention.
- the method for correcting the shape of the hot-rolled coil includes the steps of: (S 101 ) mounting the hot-rolled coil; (S 102 ) measuring the longest diameter of the hot-rolled coil; (S 103 ) adjusting the position of the hot-rolled coil; and (S 104 ) lifting.
- FIG. 3 schematically shows a method for correcting the shape of a hot-rolled coil according to one embodiment of the present invention.
- the method for correcting the shape of the hot-rolled coil includes the steps of: (S 101 ) mounting the hot-rolled coil on a hanger forming the lower part of a C-hook; (S 102 ) measuring the longest diameter of the hot-rolled coil using an outer diameter measuring means provided in the upper part of the C-hook; (S 103 ) adjusting the longest diameter of the hot-rolled coil to be perpendicular to the C-hook by means of a driving roll provided on the lower hanger; and (S 104 ) placing the C-hook, which has the hot-rolled coil mounted thereon, on a stand, followed by lifting, thereby correcting the shape of the hot-rolled coil by self-weight.
- a hot-rolled coil 100 is mounted on a hanger 201 forming the lower part of a C-hook 200 .
- the longest diameter of the hot-rolled coil 100 is measured using an outer diameter measuring means 210 provided in the upper part 202 of the C-hook.
- the longest diameter of the hot-rolled coil 100 is adjusted perpendicular to the C-hook. As shown in FIG. 3( a ) , the longest diameter of the hot-rolled coil 100 is adjusted perpendicular to the C-hook.
- the C-hook 200 having the hot-rolled coil mounted thereon is placed on a stand 300 and lifted, and thus as shown in FIG. 3( f ) , the hot-rolled coil shape distorted into an elliptical shape may be corrected into a circular shape by self-weight.
- the hot-rolled coil is manufactured by a method including the steps of: reheating a steel slab including 0.18 to 0.56 wt % carbon (C), 0.1 to 0.5 wt % silicon (Si), 0.7 to 6.5 wt % manganese (Mn), more than 0 wt % but not more than 0.02 wt % phosphorus (P), more than 0 wt % but not more than 0.02 wt % sulfur (S), more than 0 wt % but not more than 0.3 wt % chromium (Cr), more than 0 wt % but not more than 0.004 wt % boron (B), 0.01 to 0.04 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities; hot-rolling the steel slab at a finishing mill delivery temperature of 850° C.
- C 0.18 to 0.56 wt % carbon
- Si 0.1 to 0.5 wt % silicon
- the hot-rolled coil may be manufactured by cooling the hot-rolled sheet, followed by coiling at a coiling temperature of 700° C. to 900° C.
- the manufactured hot-rolled coil may include ferrite and bainite microstructures.
- the method for manufacturing the hot-rolled coil may be performed using the same steel slab as used in the above-described method for manufacturing the hot-rolled coil, and thus the detailed description thereof is omitted.
- the hot-rolled coil may be a medium-carbon hot-rolled material. It may include 0.21 to 0.37 wt % carbon (C), 0.1 to 0.4 wt % silicon (Si), 1.1 to 1.5 wt % manganese (Mn), more than 0 wt % but not more than 0.02 wt % phosphorus (P), more than 0 wt % but not more than 0.02 wt % sulfur (S), 0.1 to 0.3 wt % chromium (Cr), 0.001 to 0.004 wt % boron (B), 0.01 to 0.04 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities.
- C carbon
- Si silicon
- Mn manganese
- P more than 0 wt % but not more than 0.02 wt % phosphorus
- S 0.1 to 0.3 wt % chromium (Cr)
- Cr 0.001 to 0.004
- the hot-rolled coil may be a high-manganese hot-rolled material. It may include 0.18 to 0.25 wt % carbon, 0.3 to 0.5 wt % silicon (Si), 2 to 6.5 wt % manganese (Mn), more than 0 wt % but not more than 0.02 wt % phosphorus (P), more than 0 wt % but not more than 0.01 wt % sulfur (S), more than 0 wt % but not more than 0.1 wt % chromium (Cr), more than 0 wt % but not more than 0.001 wt % boron (B), 0.01 to 0.04 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities.
- the hot-rolled coil may be a high-carbon hot-rolled material. It may include 0.5 to 0.56 wt % carbon (C), 0.1 to 0.3 wt % silicon (Si), 0.7 to 1 wt % manganese (Mn), more than 0 wt % but not more than 0.02 wt % phosphorus (P), more than 0 wt % but not more than 0.01 wt % sulfur (S), 0.1 to 0.3 wt % chromium (Cr), more than 0 wt % but not more than 0.001 wt % boron (B), 0.01 to 0.02 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities.
- C carbon
- Si silicon
- Mn manganese
- P manganese
- P more than 0 wt % but not more than 0.02 wt % phosphorus
- S sulfur
- Cr 0.1 to 0.3 wt
- shape correction When shape correction is performed for a hot-rolled coil manufactured by the method for manufacturing the hot-rolled coil according to the present invention, it may prevent the phase transformation of the steel during cooling after hot rolling, thereby preventing deterioration in the material and physical properties of the hot-rolled coil while exhibiting an excellent effect of preventing deformation of the hot-rolled coil.
- the use of correction by self-weight and gravity makes it possible to prevent surface defects (such as scratches) of the hot-rolled coil, which occur when correction by an external force is used.
- it may exclude an existing correction apparatus employing an external force, thus reducing the correction cost and providing excellent economic efficiency.
- a hot-rolled coil was manufactured in the same manner as described in Example 1, except that the hot-rolled sheet was coiled at a coiling temperature of 560° C.
- a hot-rolled coil was manufactured in the same manner as described in Example 1, except that the hot-rolled sheet was coiled at a coiling temperature of 600° C.
- a hot-rolled coil was manufactured in the same manner as described in Example 1, except that the hot-rolled sheet was coiled at a coiling temperature of 620° C.
- a hot-rolled coil was manufactured in the same manner as described in Example 1, except that the hot-rolled sheet was coiled at a coiling temperature of 650° C.
- FIG. 4( a ) is a photograph showing the hot-rolled coil of Example 1 according to the present invention immediately after coiling
- FIG. 4( b ) is a photograph showing the hot-rolled coil after air cooling
- FIG. 5( a ) is a photograph showing the hot-rolled coil of Example 1 according to the present invention immediately after coiling
- FIG. 5( b ) is a photograph showing the hot-rolled coil after air cooling
- FIG. 6( a ) is a photograph showing a hot-rolled coil of a comparative example for the present invention immediately after coiling
- FIG. 6( b ) is a photograph showing the hot-rolled coil after air cooling. Referring to FIGS.
- Example 4( a ) and 4( b ) in Example 1, bulging defects were not observed immediately after coiling of the hot-rolled coil, but bulging defects were observed after air cooling. However, it could be seen that the degree of bulging defects was smaller than that in the Comparative Example.
- FIGS. 5( a ) and 5( b ) in Example 2, bulging defects were not observed immediately after coiling of the hot-rolled coil and after air cooling.
- FIGS. 6( a ) and 6( b ) in the Comparative Example, bulging defects were observed immediately after coiling of the hot-rolled coil, and it could be seen that the degree of the bulging defects become more severe as air cooling proceeded.
- FIG. 7 is a graph comparing the phase transformation curves of hot-rolled coils with the passage of hot-rolled coil manufacturing time and shape correction time in Example 1 and Comparative Example 1.
- Example 1 of the present invention in which a specific alloying element system was applied and coiling was performed at a temperature (700° C.) equal to or higher than the phase transformation temperature, and thus phase transformation to ferrite proceeded after a certain time after manufacturing of the hot-rolled coil, it could be seen that the time taken for phase transformation to be completed increased rapidly due to slow cooling (air cooling) of the coil after coiling, indicating that Example 1 was advantageous for shape correction.
- the occurrence of bulging of the hot-rolled coil could be reduced, thereby reducing additional operations caused by breakage of the inner coil part, delayed operation time, facility breakage, etc., which would occur due to the bulging coil in a subsequent correction process, thereby providing effects, including increased work efficiency, increased material quality, reduced rate of occurrence of defective products disposed of as scrap, etc.
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Abstract
Description
- This application is the national phase under 35 U.S.C. § 371 of PCT International Application No. PCT/KR2017/007870, filed Jul. 21, 2017, which claims the benefit of and priority to Korean Patent Application No. 10-2016-0093096 filed on Jul. 22, 2016, the entire content of each being incorporated by reference herein.
- The present invention relates to a method for manufacturing a hot-rolled coil and a method for correcting the shape of a hot-rolled coil. More specifically, the present invention relates to a method for manufacturing a hot-rolled coil for preventing shape defects, which may prevent shape defects from being caused by self-weight during manufacturing of the hot-rolled coil, and to a method for correcting the shape of a hot-rolled coil.
- In recent years, ensuring light weight has been considered to be an important factor in the development of automobile materials. This is intended to replace existing parts with high-strength materials, thereby ultimately improving fuel efficiency. To this end, materials that are structural materials for automobiles have been developed so as to improve performance by adding alloying elements, including manganese (Mn), nickel (Ni), chromium (Cr), molybdenum (Mo), titanium (Ti) and the like, and cold rolling and heat-treatment processes have been applied to ensure the strength of steel.
- Background art related to the present invention is disclosed in Korean Patent Application Publication No. 1995-0016913 (published on Jul. 20, 1995; entitled “Telescopic correction apparatus for hot-rolled coil”).
- One embodiment of the present invention is intended to provide a method for manufacturing a hot-rolled coil, which has an excellent effect of preventing the deformation of the hot-rolled coil.
- Another embodiment of the present invention is intended to provide a method for correcting the shape of a hot-rolled coil, which may prevent deterioration in the material and physical properties of the hot-rolled coil.
- Still another embodiment of the present invention is intended to provide a method for correcting the shape of a hot-rolled coil, which may prevent surface defects of the hot-rolled coil from occurring when correcting the shape by application of an external force.
- Yet another embodiment of the present invention is intended to provide a method for correcting the shape of a hot-rolled coil, which has excellent economic efficiency.
- One aspect of the present invention is directed to a method for manufacturing a hot-rolled coil. In one embodiment, the method for manufacturing the hot-rolled coil includes the steps of: reheating a steel slab including 0.18 to 0.56 wt % carbon (C), 0.1 to 0.5 wt % silicon (Si), 0.7 to 6.5 wt % manganese (Mn), more than 0 but not more than 0.02 wt % phosphorus (P), more than 0 wt % but not more than 0.02 wt % sulfur (S), more than 0 wt % but not more than 0.3 wt % chromium (Cr), more than 0 wt % but not more than 0.004 wt % boron (B), 0.01 to 0.04 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities; hot-rolling the steel slab at a finishing mill delivery temperature of 850° C. to 950° C., thereby forming a hot-rolled sheet; and cooling the hot-rolled sheet, followed by coiling at a coiling temperature of 700° C. or higher.
- In one embodiment, the steel slab may include 0.21 to 0.37 wt % carbon (C), 0.1 to 0.4 wt % silicon (Si), 1.1 to 1.5 wt % manganese (Mn), more than 0 wt % but not more than 0.02 wt % phosphorus (P), more than 0 wt % but not more than 0.02 wt % sulfur (S), 0.1 to 0.3 wt % chromium (Cr), 0.001 to 0.004 wt % boron (B), 0.01 to 0.04 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities.
- In one embodiment, the steel slab may include 0.18 to 0.25 wt % carbon, 0.3 to 0.5 wt % silicon (Si), 2 to 6.5 wt % manganese (Mn), more than 0 wt % but not more than 0.02 wt % phosphorus (P), more than 0 wt % but not more than 0.01 wt % sulfur (S), more than 0 wt % but not more than 0.1 wt % chromium (Cr), more than 0 wt % but not more than 0.001 wt % boron (B), 0.01 to 0.04 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities.
- In one embodiment, the steel slab may include 0.5 to 0.56 wt % carbon (C), 0.1 to 0.3 wt % silicon (Si), 0.7 to 1 wt % manganese (Mn), more than 0 wt % but not more than 0.02 wt % phosphorus (P), more than 0 wt % but not more than 0.01 wt % sulfur (S), 0.1 to 0.3 wt % chromium (Cr), more than 0 wt % but not more than 0.001 wt % boron (B), 0.01 to 0.02 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities.
- Another aspect of the present invention is directed to a method for correcting the shape of a hot-rolled coil. In one embodiment, the method for correcting the shape of the hot-rolled coil includes the steps of: mounting the hot-rolled coil on a hanger forming the lower part of a C-hook; measuring the longest diameter of the hot-rolled coil using an outer diameter measuring means provided in the upper part of the C-hook; adjusting the longest diameter of the hot-rolled coil to be perpendicular to the C-hook by means of a driving roll provided on the hanger; and placing the C-hook, which has the hot-rolled coil mounted thereon, on a stand, followed by lifting, thereby correcting the shape of the hot-rolled coil by self-weight.
- Still another aspect of the present invention is directed to a method for correcting the shape of a hot-rolled coil. In one embodiment, the method for correcting the shape of the hot-rolled coil includes the steps of: mounting the hot-rolled coil on a hanger forming the lower part of a C-hook; measuring the longest diameter of the hot-rolled coil using an outer diameter measuring means provided in the upper part of the C-hook; adjusting the longest diameter of the hot-rolled coil to be perpendicular to the C-hook by means of a driving roll provided on the lower hanger; and placing the C-hook, which has the hot-rolled coil mounted thereon, on a stand, followed by lifting, thereby correcting the shape of the hot-rolled coil by self-weight, wherein the hot-rolled coil is manufactured by a method including the steps of: reheating a steel slab including 0.18 to 0.56 wt % carbon (C), 0.1 to 0.5 wt % silicon (Si), 0.7 to 6.5 wt % manganese (Mn), more than 0 wt % but not more than 0.02 wt % phosphorus (P), more than 0 wt % but not more than 0.02 wt % sulfur (S), more than 0 wt % but not more than 0.3 wt % chromium (Cr), more than 0 wt % but not more than 0.004 wt % boron (B), 0.01 to 0.04 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities; hot-rolling the steel slab at a finishing mill delivery temperature of 850° C. to 950° C., thereby forming a hot-rolled sheet; and cooling the hot-rolled sheet, followed by coiling at a coiling temperature of 700° C. or higher.
- In one embodiment, the hot-rolled coil may include 0.21 to 0.37 wt % carbon (C), 0.1 to 0.4 wt % silicon (Si), 1.1 to 1.5 wt % manganese (Mn), more than 0 wt % but not more than 0.02 wt % phosphorus (P), more than 0 wt % but not more than 0.02 wt % sulfur (S), 0.1 to 0.3 wt % chromium (Cr), 0.001 to 0.004 wt % boron (B), 0.01 to 0.04 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities.
- In one embodiment, the hot-rolled sheet may be cooled and coiled at a coiling temperature of 700° C. to 900° C.
- When shape correction is performed for a hot-rolled coil manufactured by the method for manufacturing the hot-rolled coil according to the present invention, it may delay the phase transformation of the steel during cooling after hot rolling, thereby preventing deterioration in the material and physical properties of the hot-rolled coil while exhibiting an excellent effect of preventing deformation of the hot-rolled coil. In addition, the use of correction by self-weight and gravity makes it possible to prevent surface defects (such as scratches) of the hot-rolled coil, which occur when correction by an external force is used. In addition, it may reduce the correction cost and provide excellent economic efficiency.
-
FIG. 1 shows a method for manufacturing a hot-rolled coil according to one embodiment of the present invention. -
FIG. 2 shows a method for correcting the shape of a hot-rolled coil according to one embodiment of the present invention. -
FIG. 3 schematically shows a method for correcting the shape of a hot-rolled coil according to one embodiment of the present invention. -
FIG. 4(a) is a photograph showing a hot-rolled coil according to one example of the present invention immediately after coiling, andFIG. 4(b) is a photograph showing the hot-rolled coil after air cooling. -
FIG. 5(a) is a photograph showing a hot-rolled coil according to another example of the present invention immediately after coiling, andFIG. 5(b) is a photograph showing the hot-rolled coil after air cooling. -
FIG. 6(a) is a photograph showing a hot-rolled coil of a comparative example for the present invention immediately after coiling, andFIG. 6(b) is a photograph showing the hot-rolled coil after air cooling. -
FIG. 7 is a graph comparing the phase transformation curves of hot-rolled coils with the passage of hot-rolled coil manufacturing time and shape correction time in an example of the present invention and a comparative example for the present invention. - Hereinafter, the present invention will be described in detail. In the following description of the present invention, the detailed description of related known technologies or configurations will be omitted when it may unnecessarily obscure the subject matter of the present invention.
- In addition, the terms used in the following description are defined in consideration of their functions in the present invention and may vary depending on a user's or operator's intension or usual practice. Accordingly, the definition should be made based on the contents through the specification that describes the present invention.
- Method for Manufacturing Hot-Rolled Coil
- One aspect of the present invention is directed to a method for manufacturing a hot-rolled coil.
FIG. 1 shows a method for manufacturing a hot-rolled coil according to one embodiment of the present invention. In one embodiment, the method for manufacturing the hot-rolled coil includes the steps of: (S10) reheating a steel slab; (S20) hot rolling; and (S30) coiling. More specifically, the method for manufacturing the hot-rolled coil includes the steps of: (S10) reheating a steel slab including 0.18 to 0.56 wt % carbon (C), 0.1 to 0.5 wt % silicon (Si), 0.7 to 6.5 wt % manganese (Mn), more than 0 wt % but not more than 0.02 wt % phosphorus (P), more than 0 wt % but not more than 0.02 wt % sulfur (S), more than 0 wt % but not more than 0.3 wt % chromium (Cr), more than 0 wt % but not more than 0.004 wt % boron (B), 0.01 to 0.04 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities; (S20) hot-rolling the steel slab at a finishing mill delivery temperature of 850° C. to 950° C., thereby forming a hot-rolled sheet; and (S30) cooling the hot-rolled sheet, followed by coiling at a coiling temperature of 700° C. or higher. - Hereinafter, each step of the method for manufacturing the hot-rolled coil according to the present invention will be described in detail.
- (S10) Steel Slab Reheating Step
- This step is a step of reheating a steel slab including 0.18 to 0.56 wt % carbon (C), 0.1 to 0.5 wt % silicon (Si), 0.7 to 6.5 wt % manganese (Mn), more than 0 wt % but not more than 0.02 wt % phosphorus (P), more than 0 wt % but not more than 0.02 wt % sulfur (S), more than 0 wt % but not more than 0.3 wt % chromium (Cr), more than 0 wt % but not more than 0.004 wt % boron (B), 0.01 to 0.04 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities.
- Hereinafter, the components included in the steel slab will be described in detail.
- Carbon (C)
- Carbon (C) is added to ensure strength. Carbon is contained in an amount of 0.18 to 0.56 wt % based on the total weight of the steel slab. If the content of carbon is less than 0.18 wt %, it may be difficult to ensure sufficient strength. On the other hand, if the content of carbon is more than 0.56 wt %, toughness may be reduced.
- Silicon (Si)
- Silicon (Si) functions as a deoxidizer for removing oxygen from the steel and is added for solid solution strengthening. In one embodiment, silicon is contained in an amount of 0.1 to 0.5 wt % based on the total weight of the steel slab. If the content of silicon is less than 0.1 wt %, the effect of adding the same will be insufficient, and if the content of silicon is more than 0.5 wt %, it may reduce weldability and produce red scale during reheating and hot rolling, thus adversely affecting the surface quality. In addition, it may adversely affect the coating property after welding.
- Manganese (Mn)
- Manganese (Mn) is a solid solution strengthening element which is effective in ensuring strength by increasing the hardenability of the steel. In addition, manganese is an austenite stabilizing element which contributes to ferrite grain refinement by delaying ferrite and pearlite transformation.
- In one embodiment, manganese is contained in 0.7 to 6.5 wt % based on the total weight of the steel slab. If the content of manganese is less than 0.7 wt %, the solid solution strengthening effect may be insufficient. On the other hand, the content of manganese is more than 6.5 wt %, weldability may be greatly reduced. In addition, a problem may arise in that the ductility of the steel sheet is greatly reduced due to the formation of an MnS inclusion and the occurrence of central segregation.
- Phosphorus (P)
- Phosphorus (P) is added to inhibit cementite formation and increase strength. However, phosphorus deteriorates weldability and causes a difference in final properties by slab center segregation. For this reason, in the present invention, the content of phosphorus (P) is limited to more than 0 wt % but not more than 0.02 wt % based on the total weight of the steel slab.
- Sulfur
- Sulfur (S) is an element that reduces the toughness and weldability of the steel and binds to manganese to form a non-metallic inclusion (MnS) that causes cracks during processing of the steel. For this reason, the content of sulfur (S) is limited to more than 0 wt % but not more than 0.02 wt % based on the total weight of the steel slab.
- Chromium (Cr)
- Chromium is added for the purpose of increasing the hardenability and strength of the steel. In one embodiment, chromium is contained in an amount of more than 0 wt % but not more than 0.3 wt % based on the total weight of the steel slab. If the content of chromium is more than 0.3 wt %, the toughness of the hot-rolled coil may be reduced.
- Boron (B)
- Boron (B) is added for the purpose of compensating for hardenability by replacing the expensive hardening element molybdenum, and has the effect of refining grains by increasing the austenite grain growth temperature.
- In one embodiment, boron is contained in an amount of more than 0 wt % but not more than 0.004 wt % based on the total weight of the steel slab. If boron is contained in an amount of more than 0.004 wt %, the risk of reducing elongation may increase.
- Titanium (Ti)
- Titanium (Ti) is added for the purpose of enhancing hardenability and improving properties by precipitate formation. In addition, it effectively contributes to austenite grain refinement by forming precipitate phases such as Ti(C,N) at high temperature.
- In one embodiment, titanium is contained in an amount of 0.01 to 0.04 wt % based on the total weight of the steel slab. If titanium is contained in an amount of less than 0.01 wt %, the effect of adding the same may be insufficient, and if titanium is contained in an amount of more than 0.04 wt %, continuous casting defects may occur, it may be difficult to ensure the physical properties of the hot-rolled coil, and cracks on the surface of the hot-rolled coil may occur.
- The remainder other than the above-described components is substantially composed of iron (Fe). As used herein, the expression “remainder is substantially composed of iron (Fe)” means that one containing other trace elements, including inevitable impurities, may be included in the present invention, as long as it does not impair the effect of the present invention.
- In one embodiment, the steel slab may be applied to a medium-carbon hot-rolled coil. For example, the steel slab may include 0.21 to 0.37 wt % carbon (C), 0.1 to 0.4 wt % silicon (Si), 1.1 to 1.5 wt % manganese (Mn), more than 0 wt % but not more than 0.02 wt % phosphorus (P), more than 0 wt % but not more than 0.02 wt % sulfur (S), 0.1 to 0.3 wt % chromium (Cr), 0.001 to 0.004 wt % boron (B), 0.01 to 0.04 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities.
- In another embodiment, the steel slab may be applied to a high-manganese hot-rolled coil. For example, the steel slab may include 0.18 to 0.25 wt % carbon, 0.3 to 0.5 wt % silicon (Si), 2 to 6.5 wt % manganese (Mn), more than 0 wt % but not more than 0.02 wt % phosphorus (P), more than 0 wt % but not more than 0.01 wt % sulfur (S), more than 0 wt % but not more than 0.1 wt % chromium (Cr), more than 0 wt % but not more than 0.001 wt % boron (B), 0.01 to 0.04 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities.
- In still another embodiment, the steel slab may be applied to a high-carbon hot-rolled coil. For example, the steel slab may include 0.5 to 0.56 wt % carbon (C), 0.1 to 0.3 wt % silicon (Si), 0.7 to 1 wt % manganese (Mn), more than 0 wt % but not more than 0.02 wt % phosphorus (P), more than 0 wt % but not more than 0.01 wt % sulfur (S), 0.1 to 0.3 wt % chromium (Cr), more than 0 wt % but not more than 0.001 wt % boron (B), 0.01 to 0.02 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities.
- In one embodiment, the steel slab may be heated at a slab reheating temperature (SRT) of 1,150° C. to 1,250° C. At this slab reheating temperature, the effect of homogenizing the alloying elements may be excellent.
- (S20) Hot-Rolling Step
- This step is a step of hot-rolling the steel slab at a finishing mill delivery temperature of 850° C. to 950° C., thereby forming a hot-rolled sheet. When hot rolling is performed at this finishing mill delivery temperature, the hot-rolled coil may have both excellent rigidity and excellent moldability and is excellent in terms of coiling workability, and the effect of preventing deformation of the hot-rolled coil may be excellent.
- (S30) Coiling Step
- This step is a step of cooling the hot-rolled sheet, followed by coiling at a coiling temperature of 700° C. or higher. In one embodiment, the hot-rolled sheet may be cooled to the coiling temperature and coiled at that temperature. In one embodiment, the cooling may be performed by air cooling without using cooling water. When the cooling is performed under the above-described conditions, the occurrence of bulging defects on the hot-rolled coil may be effectively reduced. As used herein, the “bulging defects” may refer to shape distortion defects of the hot-rolled coil. Specifically, the “bulging defects” may refer to shape distortion defects caused by the change of the inner and outer diameters of the hot-rolled coil to an ellipse rather than a circle, due to the distortion of the hot-rolled coil in the direction of gravity, among shape defects that occur on the hot-rolled coil.
- After the sheet including the alloying components of the present invention is hot-rolled, the control of cooling may be performed such that the coiling is completed at a temperature equal to or higher than a temperature at which phase transformation begins. When coiling is performed at the above-described coiling temperature, ferrite phase transformation begins after a certain time after the coiling, and for this reason, the time taken for phase transformation to be completed may increase rapidly due to slow cooling (air cooling) of the coil after the coiling, thereby advantageously preventing shape deformation. Namely, one embodiment of the present invention may provide process conditions that delay the time point of occurrence of phase transformation after coiling as much as possible.
- If the hot-rolled sheet is coiled at a coiling temperature lower than 700° C., phase transformation of the hot-rolled sheet may proceed in the cooling process, and additional phase transformation may occur after formation of the hot-rolled coil, resulting in an increase in the coil volume, and then the hot-rolled coil may shrink with lowering temperature and the shape thereof is deformed to an elliptical shape by self-weight, thus causing bulging defects. In one embodiment, the hot-rolled sheet may be cooled and coiled at a coiling temperature of 700° C. to 900° C. For example, the coiling may be performed at a coiling temperature of 730° C. to 820° C. The manufactured hot-rolled coil may include ferrite and bainite microstructures.
- Method for Correcting Shape of Hot-Rolled Coil
- Another aspect of the present invention is directed to a method for correcting the shape of a hot-rolled coil.
FIG. 2 shows a method for correcting the shape of a hot-rolled coil according to one embodiment of the present invention. Referring toFIG. 2 , the method for correcting the shape of the hot-rolled coil includes the steps of: (S101) mounting the hot-rolled coil; (S102) measuring the longest diameter of the hot-rolled coil; (S103) adjusting the position of the hot-rolled coil; and (S104) lifting. -
FIG. 3 schematically shows a method for correcting the shape of a hot-rolled coil according to one embodiment of the present invention. Referring toFIG. 3 , the method for correcting the shape of the hot-rolled coil includes the steps of: (S101) mounting the hot-rolled coil on a hanger forming the lower part of a C-hook; (S102) measuring the longest diameter of the hot-rolled coil using an outer diameter measuring means provided in the upper part of the C-hook; (S103) adjusting the longest diameter of the hot-rolled coil to be perpendicular to the C-hook by means of a driving roll provided on the lower hanger; and (S104) placing the C-hook, which has the hot-rolled coil mounted thereon, on a stand, followed by lifting, thereby correcting the shape of the hot-rolled coil by self-weight. - For example, as shown in
FIG. 3(a) , a hot-rolledcoil 100 is mounted on ahanger 201 forming the lower part of a C-hook 200. As shown inFIG. 3(b) , the longest diameter of the hot-rolledcoil 100 is measured using an outer diameter measuring means 210 provided in theupper part 202 of the C-hook. Next, as shown inFIG. 3(c) , using a drivingroll 220 provided on thehanger 201 forming the lower part, the longest diameter of the hot-rolledcoil 100 is adjusted perpendicular to the C-hook. As shown inFIG. 3(e) , the C-hook 200 having the hot-rolled coil mounted thereon is placed on astand 300 and lifted, and thus as shown inFIG. 3(f) , the hot-rolled coil shape distorted into an elliptical shape may be corrected into a circular shape by self-weight. - The hot-rolled coil is manufactured by a method including the steps of: reheating a steel slab including 0.18 to 0.56 wt % carbon (C), 0.1 to 0.5 wt % silicon (Si), 0.7 to 6.5 wt % manganese (Mn), more than 0 wt % but not more than 0.02 wt % phosphorus (P), more than 0 wt % but not more than 0.02 wt % sulfur (S), more than 0 wt % but not more than 0.3 wt % chromium (Cr), more than 0 wt % but not more than 0.004 wt % boron (B), 0.01 to 0.04 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities; hot-rolling the steel slab at a finishing mill delivery temperature of 850° C. to 950° C., thereby forming a hot-rolled sheet; and cooling the hot-rolled sheet, followed by coiling at a coiling temperature of 700° C. or higher. In one embodiment, the hot-rolled coil may be manufactured by cooling the hot-rolled sheet, followed by coiling at a coiling temperature of 700° C. to 900° C. The manufactured hot-rolled coil may include ferrite and bainite microstructures.
- The method for manufacturing the hot-rolled coil may be performed using the same steel slab as used in the above-described method for manufacturing the hot-rolled coil, and thus the detailed description thereof is omitted.
- In one embodiment, the hot-rolled coil may be a medium-carbon hot-rolled material. It may include 0.21 to 0.37 wt % carbon (C), 0.1 to 0.4 wt % silicon (Si), 1.1 to 1.5 wt % manganese (Mn), more than 0 wt % but not more than 0.02 wt % phosphorus (P), more than 0 wt % but not more than 0.02 wt % sulfur (S), 0.1 to 0.3 wt % chromium (Cr), 0.001 to 0.004 wt % boron (B), 0.01 to 0.04 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities.
- In another embodiment, the hot-rolled coil may be a high-manganese hot-rolled material. It may include 0.18 to 0.25 wt % carbon, 0.3 to 0.5 wt % silicon (Si), 2 to 6.5 wt % manganese (Mn), more than 0 wt % but not more than 0.02 wt % phosphorus (P), more than 0 wt % but not more than 0.01 wt % sulfur (S), more than 0 wt % but not more than 0.1 wt % chromium (Cr), more than 0 wt % but not more than 0.001 wt % boron (B), 0.01 to 0.04 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities.
- In still another embodiment, the hot-rolled coil may be a high-carbon hot-rolled material. It may include 0.5 to 0.56 wt % carbon (C), 0.1 to 0.3 wt % silicon (Si), 0.7 to 1 wt % manganese (Mn), more than 0 wt % but not more than 0.02 wt % phosphorus (P), more than 0 wt % but not more than 0.01 wt % sulfur (S), 0.1 to 0.3 wt % chromium (Cr), more than 0 wt % but not more than 0.001 wt % boron (B), 0.01 to 0.02 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities.
- When shape correction is performed for a hot-rolled coil manufactured by the method for manufacturing the hot-rolled coil according to the present invention, it may prevent the phase transformation of the steel during cooling after hot rolling, thereby preventing deterioration in the material and physical properties of the hot-rolled coil while exhibiting an excellent effect of preventing deformation of the hot-rolled coil. In addition, the use of correction by self-weight and gravity makes it possible to prevent surface defects (such as scratches) of the hot-rolled coil, which occur when correction by an external force is used. In addition, it may exclude an existing correction apparatus employing an external force, thus reducing the correction cost and providing excellent economic efficiency.
- Hereinafter, the constitution and effects of the present invention will be described in more detail with reference to preferred examples. However, these examples are given merely as illustrative of the present invention and are not to be construed as limiting the scope of the present invention in any way.
- As a medium-carbon material, a steel slab including 0.23 wt % carbon (C), 0.2 wt % silicon (Si), 1.2 wt % manganese (Mn), 0.015 wt % phosphorus (P), 0.01 wt % sulfur (S), 0.2 wt % chromium (Cr), 0.003 wt % boron (B), 0.02 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities, was reheated at 1200° C., and the steel slab was hot-rolled at a finishing mill delivery temperature of 880° C., thereby forming a hot-rolled sheet. Then, the hot-rolled sheet was cooled and coiled at a coiling temperature of 700° C., thereby manufacturing a hot-rolled coil.
- As a high-manganese material, a steel slab including 0.2 wt % carbon (C), 0.4 wt % silicon (Si), 6 wt % manganese (Mn), 0.015 wt % phosphorus (P), 0.01 wt % sulfur (S), 0.05 wt % chromium (Cr), 0.001 wt % boron (B), 0.02 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities, was reheated at 1200° C., and the steel slab was hot-rolled at a finishing mill delivery temperature of 940° C., thereby forming a hot-rolled sheet. Then, the hot-rolled sheet was cooled and coiled at a coiling temperature of 700° C., thereby manufacturing a hot-rolled coil.
- As a high-carbon material, a steel slab including 0.55 wt % carbon (C), 0.2 wt % silicon (Si), 0.8 wt % manganese (Mn), 0.015 wt % phosphorus (P), 0.01 wt % sulfur (S), 0.2 wt % chromium (Cr), 0.001 wt % boron (B), 0.01 wt % titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities, was reheated at 1200° C., and the steel slab was hot-rolled at a finishing mill delivery temperature of 890° C., thereby forming a hot-rolled sheet. Then, the hot-rolled sheet was cooled and coiled at a coiling temperature of 730° C., thereby manufacturing a hot-rolled coil.
- A hot-rolled coil was manufactured in the same manner as described in Example 1, except that the hot-rolled sheet was coiled at a coiling temperature of 560° C.
- A hot-rolled coil was manufactured in the same manner as described in Example 1, except that the hot-rolled sheet was coiled at a coiling temperature of 600° C.
- A hot-rolled coil was manufactured in the same manner as described in Example 1, except that the hot-rolled sheet was coiled at a coiling temperature of 620° C.
- A hot-rolled coil was manufactured in the same manner as described in Example 1, except that the hot-rolled sheet was coiled at a coiling temperature of 650° C.
-
FIG. 4(a) is a photograph showing the hot-rolled coil of Example 1 according to the present invention immediately after coiling, andFIG. 4(b) is a photograph showing the hot-rolled coil after air cooling.FIG. 5(a) is a photograph showing the hot-rolled coil of Example 1 according to the present invention immediately after coiling, andFIG. 5(b) is a photograph showing the hot-rolled coil after air cooling.FIG. 6(a) is a photograph showing a hot-rolled coil of a comparative example for the present invention immediately after coiling, andFIG. 6(b) is a photograph showing the hot-rolled coil after air cooling. Referring toFIGS. 4(a) and 4(b) , in Example 1, bulging defects were not observed immediately after coiling of the hot-rolled coil, but bulging defects were observed after air cooling. However, it could be seen that the degree of bulging defects was smaller than that in the Comparative Example. Referring toFIGS. 5(a) and 5(b) , in Example 2, bulging defects were not observed immediately after coiling of the hot-rolled coil and after air cooling. Referring toFIGS. 6(a) and 6(b) , in the Comparative Example, bulging defects were observed immediately after coiling of the hot-rolled coil, and it could be seen that the degree of the bulging defects become more severe as air cooling proceeded. - Correction of Shape of Hot-Rolled Coil
- For the hot-rolled coils of Examples 1 to 3 and Comparative Examples 1 to 4, shape correction was performed. Each of the hot-rolled coil was mounted on a hanger forming the lower part of a C-hook, and the longest diameter of the hot-rolled coil was measured using an outer diameter measuring means provided on the upper part of the C-hook. Thereafter, using a driving roll provided on the hanger, the longest diameter of the hot-rolled coil was adjusted to be perpendicular to the C-hook. The C-hook having the hot-rolled coil mounted thereon was placed on a stand and lifted, thereby correcting the shape of the hot-rolled coil by self-weight.
- For Examples 1 to 3 and Comparative Examples 1 to 4, the inner diameter of the coils and whether bulging defects would be corrected after shape correction were observed, and the results of the observation are shown in Table 1 below.
-
TABLE 1 Whether bulging Coiling Coil inner defects would be temperature diameter corrected by shape (° C.) (mm) correction Example 1 700 740 Corrected Example 2 730 760 Corrected Example 3 730 740 Corrected Comparative 560 700 Not corrected Example 1 Comparative 600 710 Not corrected Example 2 Comparative 620 680 Not corrected Example 3 Comparative 650 720 Not corrected Example 4 - Referring to Table 1 above, it could be seen that, in the case of Examples 1 to 3, bulging defects did not appear after correction, but in the case of Comparative Examples 1 to 4 which were out of the coiling temperature of the present invention, bulging defects were not properly corrected even after correction.
-
FIG. 7 is a graph comparing the phase transformation curves of hot-rolled coils with the passage of hot-rolled coil manufacturing time and shape correction time in Example 1 and Comparative Example 1. Referring toFIG. 7 , in the case of Example 1 of the present invention, in which a specific alloying element system was applied and coiling was performed at a temperature (700° C.) equal to or higher than the phase transformation temperature, and thus phase transformation to ferrite proceeded after a certain time after manufacturing of the hot-rolled coil, it could be seen that the time taken for phase transformation to be completed increased rapidly due to slow cooling (air cooling) of the coil after coiling, indicating that Example 1 was advantageous for shape correction. However, in the case of Comparative Example 1 in which coiling was performed at a temperature lower than the phase transformation temperature of the hot-rolled sheet, it could be seen that phase transformation to ferrite occurred earlier than in Example 1, making it difficult to ensure the time of start of the phase transformation of the present invention, indicating that Comparative Example 1 was disadvantageous for shape correction. - In addition, in accordance with the methods for manufacturing the hot-rolled coil and correcting the shape of the hot-rolled coil according to the present invention, the occurrence of bulging of the hot-rolled coil could be reduced, thereby reducing additional operations caused by breakage of the inner coil part, delayed operation time, facility breakage, etc., which would occur due to the bulging coil in a subsequent correction process, thereby providing effects, including increased work efficiency, increased material quality, reduced rate of occurrence of defective products disposed of as scrap, etc.
- Simple modifications or alterations of the present invention may be easily made by those skilled in the art, and such modifications or alterations may be considered to be all included within the scope of the present invention.
Claims (9)
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KR1020160093096A KR101787275B1 (en) | 2016-07-22 | 2016-07-22 | Manufacturing method for hot rolled coil and method for correcting shape of hot rolled coil |
PCT/KR2017/007870 WO2018016908A1 (en) | 2016-07-22 | 2017-07-21 | Method for manufacturing hot-rolled coil, and method for shape-correction of hot-rolled coil |
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US4026495A (en) * | 1976-02-02 | 1977-05-31 | Aluminum Company Of America | Rotating tubing payoff system |
KR950010215B1 (en) | 1993-12-27 | 1995-09-12 | 포항종합제철주식회사 | Proofreading device for telescope of rolling coil |
JP3295693B2 (en) * | 1995-07-13 | 2002-06-24 | 日鐵建材工業株式会社 | Coil moving trolley in uncoiler equipment |
JP4345542B2 (en) * | 2004-03-30 | 2009-10-14 | Jfeスチール株式会社 | Coil outer diameter measuring method and apparatus |
KR100782754B1 (en) * | 2006-07-11 | 2007-12-05 | 주식회사 포스코 | An apparatus for changing c-hook direction of wire-rod coil |
JP5056876B2 (en) * | 2010-03-19 | 2012-10-24 | Jfeスチール株式会社 | Hot-rolled steel sheet with excellent cold workability and hardenability and method for producing the same |
JP5594578B2 (en) * | 2010-05-17 | 2014-09-24 | 新日鐵住金株式会社 | Manufacturing method of hot rolled coil |
CN202667319U (en) * | 2012-06-15 | 2013-01-16 | 鞍钢股份有限公司 | Flattening-and-rolling prevention carrier roller device |
JP6265108B2 (en) * | 2014-11-07 | 2018-01-24 | Jfeスチール株式会社 | Hot-rolled steel sheet for cold-rolled steel sheet or hot-dip galvanized steel sheet and method for producing the same |
CN105728496B (en) * | 2016-03-11 | 2017-12-29 | 攀钢集团西昌钢钒有限公司 | A kind of redemption restorative procedure for the flat volume defect of Thin Specs |
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DE112017003683T5 (en) | 2019-04-04 |
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