CN111587298A - Hot-rolled hot-dip galvanized steel sheet having excellent surface appearance and method for manufacturing same - Google Patents
Hot-rolled hot-dip galvanized steel sheet having excellent surface appearance and method for manufacturing same Download PDFInfo
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- CN111587298A CN111587298A CN201880084538.1A CN201880084538A CN111587298A CN 111587298 A CN111587298 A CN 111587298A CN 201880084538 A CN201880084538 A CN 201880084538A CN 111587298 A CN111587298 A CN 111587298A
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- 229910001335 Galvanized steel Inorganic materials 0.000 title claims abstract description 46
- 239000008397 galvanized steel Substances 0.000 title claims abstract description 46
- 238000000034 method Methods 0.000 title claims description 34
- 238000004519 manufacturing process Methods 0.000 title claims description 29
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 137
- 239000010959 steel Substances 0.000 claims abstract description 137
- 238000007747 plating Methods 0.000 claims description 59
- 238000005554 pickling Methods 0.000 claims description 36
- 239000011701 zinc Substances 0.000 claims description 31
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 26
- 238000005246 galvanizing Methods 0.000 claims description 24
- 238000005096 rolling process Methods 0.000 claims description 21
- 229910052725 zinc Inorganic materials 0.000 claims description 18
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 16
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 16
- 230000008569 process Effects 0.000 claims description 13
- 239000000243 solution Substances 0.000 claims description 13
- 238000005422 blasting Methods 0.000 claims description 11
- 230000003746 surface roughness Effects 0.000 claims description 9
- 239000003929 acidic solution Substances 0.000 claims description 7
- 239000012535 impurity Substances 0.000 claims description 7
- 238000007598 dipping method Methods 0.000 claims description 6
- 235000021110 pickles Nutrition 0.000 claims description 4
- 239000010410 layer Substances 0.000 description 99
- 239000000126 substance Substances 0.000 description 28
- 230000007547 defect Effects 0.000 description 21
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 12
- 239000002344 surface layer Substances 0.000 description 11
- 230000015572 biosynthetic process Effects 0.000 description 8
- 230000000694 effects Effects 0.000 description 8
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 6
- 238000007654 immersion Methods 0.000 description 6
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 6
- 229910052760 oxygen Inorganic materials 0.000 description 6
- 239000011787 zinc oxide Substances 0.000 description 6
- 239000000463 material Substances 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 4
- 230000003749 cleanliness Effects 0.000 description 4
- 238000009826 distribution Methods 0.000 description 4
- 230000006872 improvement Effects 0.000 description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 230000003647 oxidation Effects 0.000 description 4
- 238000007254 oxidation reaction Methods 0.000 description 4
- 238000005480 shot peening Methods 0.000 description 4
- 239000002253 acid Substances 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- 239000012530 fluid Substances 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 239000011247 coating layer Substances 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 238000003618 dip coating Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229910000765 intermetallic Inorganic materials 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 230000035484 reaction time Effects 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 229920006395 saturated elastomer Polymers 0.000 description 2
- 238000007789 sealing Methods 0.000 description 2
- 238000009751 slip forming Methods 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000005238 degreasing Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 230000003628 erosive effect Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 238000010884 ion-beam technique Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- FBAFATDZDUQKNH-UHFFFAOYSA-M iron chloride Chemical compound [Cl-].[Fe] FBAFATDZDUQKNH-UHFFFAOYSA-M 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 239000010731 rolling oil Substances 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
Images
Classifications
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- 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
- C23C2/14—Removing excess of molten coatings; Controlling or regulating the coating thickness
- C23C2/16—Removing excess of molten coatings; Controlling or regulating the coating thickness using fluids under pressure, e.g. air knives
- C23C2/18—Removing excess of molten coatings from elongated material
- C23C2/20—Strips; Plates
-
- 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
-
- 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
- B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
- B21B45/04—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for de-scaling, e.g. by brushing
- B21B45/06—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for de-scaling, e.g. by brushing of strip material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
- B24C1/00—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods
- B24C1/08—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods for polishing surfaces, e.g. smoothing a surface by making use of liquid-borne abrasives
- B24C1/086—Descaling; Removing coating films
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C18/00—Alloys based on zinc
- C22C18/04—Alloys based on zinc with aluminium as the next major constituent
-
- 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
- C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
-
- 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
- C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
- C23C2/022—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by heating
-
- 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
- C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
- C23C2/024—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by cleaning or etching
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
- C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
- C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
- C23G1/08—Iron or steel
Abstract
The hot-rolled hot-dip galvanized steel sheet having excellent surface appearance according to an aspect of the present invention may include a base steel sheet and a galvanized layer, and the galvanized layer may include a continuous Al-concentrated layer formed within 100nm from the surface of the galvanized layer.
Description
Technical Field
The present invention relates to a hot-rolled hot-dip galvanized steel sheet and a method for manufacturing the same, and more particularly, to a hot-rolled hot-dip galvanized steel sheet having an excellent surface appearance by effectively suppressing surface defects of a plating layer, and a method for manufacturing the same.
Background
The hot-dip galvanized steel sheet is a steel sheet having a galvanized layer formed on the surface of a base steel sheet by hot dip coating, and the hot-rolled hot-dip galvanized steel sheet is a steel sheet having a galvanized layer formed on the surface of a hot-rolled steel sheet by hot dip coating. Generally, a hot-rolled hot-dip galvanized steel sheet may be manufactured through a series of processes such as scale breaking, pickling, heat treatment, plating bath dipping, and air wiping (airlifting) processes.
The pickling process is performed to remove scale (scale) formed during hot rolling, and mainly uses a chemical pickling process that removes scale on the surface of a hot-rolled steel sheet using an acidic solution. In the case of such chemical pickling, since a strong acidic solution such as sulfuric acid or hydrochloric acid is mainly used, it is harmful to the environment and also severely corrodes the base material as the reaction time increases. Therefore, there is a need for a scale removing technique capable of effectively removing scale on the surface of a hot-rolled steel sheet while minimizing the problem of environmental pollution.
In addition, the air wiping process is an essential process for adjusting the plating amount of the surface of the plated steel sheet by spraying a high-pressure fluid after immersion in a plating bath, but the high-pressure fluid is sprayed to the plating layer in a state where solidification of the plating layer is not completed, and thus surface defects such as flow mark defects may be caused. An oxide film having relatively low fluidity is formed on the surface layer portion of the plating layer, and hot dip galvanizing having relatively high fluidity exists inside the plating layer, so that a difference in fluidity occurs in the thickness direction of the plating layer. The high-pressure fluid sprayed from the air knife device reaches the surface layer portion of the plating layer, resulting in the formation of cracks in the oxide film, and the molten zinc inside the plating layer can be exposed to the outside through the cracks formed in the oxide film. Immediately after passing through the air knife device, the plating layer rapidly solidifies, and therefore, flow mark defects in the shape of valleys and peaks continuously appear in the surface layer portion of the plating layer.
In the related art, in order to prevent the flow mark defect, a technique of preventing the formation of the oxide film itself by introducing a sealing box (sealing box) for forming a non-oxidizing atmosphere has been proposed. However, although the formation of an oxide film on the surface portion of the plated layer can be suppressed to some extent by introducing the seal box, the equipment structure becomes excessively complicated, and when there is a gap between the plating bath and the seal box in order to easily discharge evaporated zinc, excessive dross is generated on the surface of the plating bath due to the reaction between the outside air and the plating bath, and the surface quality of the plated steel sheet is rather degraded.
Patent document 1 proposes a technique of mechanically removing a flow mark defect by temper rolling after the formation of a plating layer, instead of suppressing the generation of the flow mark defect itself. However, in order to remove the flow mark, the steel sheet needs to be pressed with as high a pressing force as possible, and thus the risk of damage to the normal plating and peeling of the plating is high. Therefore, it is urgently required to introduce a technique capable of effectively suppressing flow mark defects on the surface of a plated layer to prevent the surface quality of the plated steel sheet from being degraded.
(patent document 1) Korean laid-open patent publication No. 10-2001-0060423 (published 2001 07/07)
Disclosure of Invention
Technical problem to be solved
According to an aspect of the present invention, a hot-rolled hot-dip galvanized steel sheet having excellent surface appearance and a method of manufacturing the same may be provided.
The technical problem to be solved by the present invention is not limited to the above. Additional technical problems of the present invention will be readily apparent to those skilled in the art from the entire contents of the present specification.
(II) technical scheme
A hot-rolled hot-dip galvanized steel sheet according to an aspect of the present invention may include a base steel sheet and a galvanized layer, and the galvanized layer may include a continuous Al-concentrated layer formed at a depth within 100nm from a surface of the galvanized layer.
The Al-concentrated layer may be alumina (Al)2O3) And (3) a layer.
The thickness of the Al-concentrated layer may be 50nm or less (excluding 0 nm).
The surface roughness of the surface of the base steel sheet forming an interface with the zinc plating layer may be 0.7 to 2.5 μm, based on the center line average roughness (Ra).
The zinc plating layer may include 0.2 to 0.6% by weight of Al and the balance of Zn and other inevitable impurities.
A hot-rolled hot-dip galvanized steel sheet according to an aspect of the present invention may be manufactured by the following process: drawing a base steel sheet at a first elongation to generate cracks in a scale on a surface of the base steel sheet; applying physical impact to the surface of the base steel plate, and mechanically removing an oxide skin on the surface of the base steel plate; reacting the surface of the base steel plate with an acidic solution to chemically pickle the surface of the base steel plate; temper rolling the base steel plate at a second elongation to flatten the surface of the base steel plate; and dipping the base steel sheet in a hot dip galvanizing bath containing 0.2 to 0.4% by weight of Al and the balance of Zn and other unavoidable impurities to form a galvanized layer.
The first elongation may be 0.2 to 1.5%.
The surface of the base steel sheet may be subjected to shot blasting to mechanically remove scale on the surface of the base steel sheet.
The shot blasting may be performed by projecting shots having an average diameter of 0.18mm to 0.6mm at an average projection amount of 800kg/min to 1800kg/min and an average projection speed of 65m/s to 90 m/s.
The surface of the base steel sheet may be chemically pickled by immersing the base steel sheet in a hydrochloric acid solution having a temperature range of 70 to 85 ℃ and a concentration of 5 to 20% for 15 to 35 seconds.
The base steel sheet may be temper rolled by smooth rolls, and the surface roughness of the smooth rolls may be 0.1 to 0.8 μm, based on the center line average roughness (Ra).
The roughness of the surface of the temper-rolled base steel sheet may be 0.7 to 2.5 μm on the basis of the center line average roughness (Ra).
The second elongation may be 0.5% to 2.5%.
The sum of the first elongation and the second elongation may be 0.7% to 4.0%.
The second elongation may be greater than the first elongation.
The dipping temperature of the hot dip galvanizing bath of the base steel sheet may be 450 to 500 ℃.
(III) advantageous effects
According to an aspect of the present invention, it is possible to provide a hot-rolled hot-dip galvanized steel sheet having an aesthetic surface appearance by effectively suppressing the generation of flow mark defects on the surface of a galvanized layer, and a method for manufacturing the same.
According to an aspect of the present invention, it is possible to provide a method of manufacturing a hot-rolled hot-dip galvanized steel sheet, which sequentially performs mechanical descaling and chemical pickling on a base steel sheet, and thus can minimize the use of a chemical solution for chemical pickling while effectively removing residual scale on the surface of the base steel sheet.
Drawings
Fig. 1 to 3 are results of analyzing a surface layer portion of a hot-rolled hot-dip galvanized steel sheet according to an aspect of the present invention using a focused ion beam-transmission electron microscope (FIB-TEM).
Fig. 4 to 6 are results of FIB-TEM analysis of the surface layer portion of the hot-rolled hot-dip galvanized steel sheet having a discontinuous alumina layer.
Best mode for carrying out the invention
The present invention relates to a hot-rolled hot-dip galvanized steel sheet having excellent surface appearance and a method for manufacturing the same, and preferred embodiments of the present invention will be described below. The embodiments of the present invention may be modified into various forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. These examples are provided to describe the present invention in more detail to those of ordinary skill in the art.
A hot-rolled hot-dip galvanized steel sheet according to an aspect of the present invention may include a base steel sheet and a zinc coating layer formed on a surface of the base steel sheet. The base steel sheet of the present invention may be a hot rolled steel sheet, but is not limited thereto. It can be construed as including all steel sheets capable of being plated.
A hot-rolled hot-dip galvanized steel sheet according to an aspect of the present invention may include an Al-concentrated layer continuously distributed within a galvanized layer from the surface of the galvanized layer to a depth within 100 nm. That is, the Al-concentrated layer of the present invention may be continuously distributed in a direction parallel to the surface of the plated steel sheet from the surface of the plated steel sheet to a predetermined depth. In addition, the thickness of the Al-concentrated layer of the present invention may be 50nm or less (excluding 0 nm). That is, the Al-concentrated layer of the present invention is formed to a predetermined depth from the surface of the plated steel sheet and to a predetermined thickness, and may be continuously distributed in a direction parallel to the surface of the plated steel sheet.
The Al-concentrated layer of the present invention may be alumina (Al)2O3) And (3) a layer. Although the content of Al is relatively small compared to the content of Zn in the zinc plating layer of the present invention, alumina (Al) enriched can be continuously formed in the surface layer portion of the zinc plating layer2O3) Of (2) a layer of (a). This is because Al is an element having a higher oxygen affinity than Zn, and when a plating layer is formed, Al in the plating layer moves to a surface layer portion of the plating layer and combines with oxygen to form an oxide. That is, in the surface layer portion of the zinc plating layer of the present invention, the aluminum oxide layer can be formed before the formation of zinc oxide, and the formation of a continuous aluminum oxide layer can suppress the oxidation of zinc on the surface of the aluminum oxide layer.
According to the base steel sheet of the hot-dip galvanized steel sheet of one aspect of the present invention, the surface roughness of the surface forming the interface may be 0.7 μm to 2.5 μm, based on the center line average roughness (Ra). That is, since the base steel sheet of the present invention has a flat surface with a surface roughness of 0.7 to 2.5 μm based on the center line average roughness (Ra), it is possible to minimize the variation in the degree of oxidation of the surface of the base steel sheet, and to form an aluminum oxide layer distributed in a continuous form when forming a plating layer.
Fig. 1 to 3 are results of analyzing a surface layer portion of a hot-rolled hot-dip galvanized steel sheet according to an aspect of the present invention using FIB-TEM. Fig. 4 to 6 are results of FIB-TEM analysis of the surface layer portion of the hot-rolled hot-dip galvanized steel sheet having a discontinuous alumina layer.
Fig. 1 to 3 are results of analyzing the same cross section of a hot-rolled hot-dip galvanized steel sheet according to an aspect of the present invention using FIB-TEM, respectively, and show distributions of Zn, Al, and O, respectively. As shown in fig. 2 and 3, it was confirmed that Al and O were continuously distributed on the surface side of the galvanized layer and that the enriched layer in the form of alumina was continuously formed on the surface side of the galvanized layer. Further, as shown in fig. 1, it was confirmed that Zn is located at the lower portion of alumina, and thus Zn is hardly present on the surface of the alumina layer. That is, it was confirmed that zinc oxide was hardly present on the surface side of the zinc plating layer because the zinc-deficient layer was formed on the surface of the aluminum oxide layer.
On the other hand, as shown in fig. 4 to 6, in the case of the galvanized layer formed with the discontinuous alumina layer, it was confirmed that Al and O were intermittently distributed on the surface side of the plated layer and the alumina layer was intermittently formed. That is, it was confirmed that the reaction of Zn and O occurred at the intermittent positions of the alumina layer, and thus, uneven zinc oxide was exposed on the surface of the plating layer. Therefore, if the aluminum oxide layer is intermittently present on the surface side of the plating layer, the zinc oxide exposed to the outside of the plating layer is cracked in the air wiping operation after immersion in the plating bath, and the molten zinc inside the plating layer flows out to the outside of the plating layer, which may cause flow mark defects.
In addition, the zinc-plated layer of the present invention may include 0.2 to 0.6% by weight of Al and the balance of Zn and other unavoidable impurities. The composition of the galvanized layer of the present invention is affected by the composition of the hot dip galvanizing bath described later, and therefore, the description of the composition content of the galvanized layer of the present invention will be replaced by the description of the composition of the hot dip galvanizing bath described later. However, in general hot dip galvanizing, the content of Al contained in the plating layer is higher than that contained in the plating bath, and therefore, the content of Al contained in the galvanized layer of the present invention may be higher than that in the hot dip galvanizing bath. That is, the upper limit of 0.6% of the Al content contained in the galvanized layer of the present invention is a content range in consideration of the above.
A hot-rolled hot-dip galvanized steel sheet according to one aspect of the present invention has continuous alumina (Al) on a surface layer portion of a galvanized layer2O3) Accordingly, it is possible to effectively prevent the formation of non-uniform zinc oxide on the surface of the galvanized layer, and to effectively suppress the formation of flow mark defects on the surface of the hot-dip galvanized steel sheet.
Hereinafter, the manufacturing method of the present invention will be described in more detail.
A hot-rolled hot-dip galvanized steel sheet according to an aspect of the present invention may be manufactured by the following process: drawing a base steel sheet at a first elongation to generate cracks in a scale on a surface of the base steel sheet; applying physical impact to the surface of the base steel plate, and mechanically removing an oxide skin on the surface of the base steel plate; reacting the surface of the base steel plate with an acidic solution to chemically pickle the surface of the base steel plate; temper rolling the base steel plate at a second elongation to flatten the surface of the base steel plate; the base steel sheet is immersed in a hot dip galvanizing bath containing, in wt%, 0.2% to 0.4% of Al and the balance of Zn and other unavoidable impurities to form a galvanized layer.
According to the method of manufacturing a hot-rolled hot-dip galvanized steel sheet in one aspect of the present invention, it is possible to stretch a base steel sheet at a first elongation in a scale breaker (scale breaker) to remove scale on the surface of the base steel sheet, then mechanically remove scale remaining on the surface of the base steel sheet by shot blasting (shot blasting), and dip the base steel sheet subjected to shot blasting in an acidic solution to pickle the scale remaining on the surface of the base steel sheet. Therefore, the hot-rolled scale generated in the manufacturing process of the hot-rolled steel sheet can be effectively removed, and the cleanliness of the surface of the base steel sheet can be effectively ensured.
According to the method of manufacturing a hot-rolled hot-dip galvanized steel sheet in one aspect of the present invention, the descaled base steel sheet may be temper-rolled to impart roughness to flatten the surface of the steel sheet, and then the base steel sheet may be immersed in a hot-dip galvanizing bath to form a galvanized layer. That is, the flatness of the surface of the base steel sheet is ensured to be above a predetermined level by temper rolling, and thus the deviation of the degree of oxidation of the surface of the base steel sheet can be effectively reduced, so that a continuously distributed Al-concentrated layer can be formed.
Hereinafter, each process condition constituting the manufacturing method of the present invention will be described in more detail.
Oxide scale removing (scale breaking)
As a preliminary process for removing the hot-rolled oxide formed on the surface of the base steel sheet, scale removal may be performed. In descaling, the base steel sheet is drawn at the first elongation, and therefore, cracks may be generated in the hot-rolled oxide formed on the surface of the base steel sheet. Therefore, cracks are generated in the hot-rolled oxide on the surface of the base steel sheet by descaling, so that the descaling efficiency in the subsequent mechanical descaling and chemical pickling can be effectively improved.
In order to sufficiently obtain the effect of mechanically removing scale after scale removal and removing residual scale in chemical pickling, the elongation in scale removal should be a predetermined level or more. Even by mechanical descaling and chemical pickling, when a predetermined amount or more of residual scale is present, unplated or plating peeling may occur, and thus the first elongation of the present invention may be 0.2% or more. On the other hand, when the first elongation exceeds a predetermined level, the material of the base steel sheet is hardened, and the flattening effect cannot be sufficiently obtained even by temper rolling, so that the first elongation of the present invention can be limited to 1.5% or less.
Mechanical descaling
The base steel sheet from which the scale has been removed may be subjected to shot blasting. The shot peening process may be performed by projecting minute shot (shot ball) onto the surface of the base steel plate. The collision of the shot thus projected accelerates the growth of cracks formed in the scale on the surface of the base steel sheet, and the scale remaining on the surface of the base steel sheet may be detached from the surface of the base steel sheet.
The shot used for the shot peening treatment of the present invention may have a diameter of 0.18mm to 0.6 mm. This is because, when the diameter of the shot is less than 0.18mm, the amount of impact applied to the base steel sheet is insufficient, reducing the scale removal efficiency, and when the diameter of the shot exceeds 0.60mm, not only the amount of impact required for scale removal is exceeded, but also local unevenness of the impact portion of the steel sheet may be increased.
In the shot blasting of the present invention, the average shot size of the shots may be 800kg/min to 1800 kg/min. When the average shot size of the shot is too small, the collision probability with the steel sheet is reduced, and the effect of removing the residual scale cannot be expected, so that the average shot size of the shot may be 800kg/min or more. On the other hand, when the average shot size of the shot is too large, it may be too much cost compared to the improvement of the scale removal efficiency, and thus the average shot size of the shot may be 1800kg/min or less.
In the shot peening treatment of the present invention, the average projection velocity of the shot may be 65m/s to 90 m/s. When the average projection speed of the projectile is below a predetermined level, the average projection speed of the projectile may be 65m/s or more since the kinetic energy of the individual projectile is reduced and the amount of impact transmitted to the base steel plate does not reach the predetermined level. However, when the average projection velocity of the shot is too large, an impact amount more than necessary is transmitted to the base steel plate, and the surface unevenness may be increased, so the average projection velocity of the shot may be 90m/s or less.
Chemical pickling
The chemical pickling may be performed by reacting the surface of the base steel sheet, on which the shot peening has been completed, with an acidic solution. The pickling efficiency is mainly affected by factors such as the concentration of the pickling solution, temperature, and reaction time, and thus the chemical pickling efficiency can be optimally controlled by appropriately controlling these factors. Generally, hydrochloric acid or sulfuric acid may be used as the pickling solution, but hydrochloric acid has stronger corrosiveness than sulfuric acid, has an excellent surface scale removing ability, and has an advantage of a small generation degree of hydrogen embrittlement, and thus, in the chemical pickling of the present invention, a hydrochloric acid solution may be used.
The hydrochloric acid solution for chemical cleaning of the present invention may contain hydrochloric acid at a concentration of 5% or more in consideration of acid cleaning efficiency. On the other hand, when the hydrochloric acid concentration is too high, iron chloride (FeCl)2) The reaction is stopped when the concentration of (2) reaches a supersaturated state, and the pickling efficiency becomes constant or conversely decreases in the vicinity of the precipitation point, so that the hydrochloric acid solution used for the chemical pickling of the present invention may contain hydrochloric acid having a concentration of 20% or less.
In order to ensure the pickling ability, the chemical pickling of the present invention may be performed at a temperature of 70 ℃ or higher. On the other hand, when the temperature of the chemical pickling is excessively high, the degree of improvement of the pickling ability is insufficient, but excessive corrosion of the base steel sheet may be caused due to the excessive pickling, and the evaporation amount of the acid solution rapidly increases, which is not preferable in terms of economy, so that the chemical pickling of the present invention may be performed at a temperature of 85 ℃ or less.
The chemical pickling of the present invention may be performed for 15 seconds or more to provide sufficient time to remove scale remaining on the surface of the base steel sheet. However, when the chemical pickling is performed for an excessively long time, excessive corrosion of the base steel sheet may be caused due to the excessive pickling, and it takes a relatively long time to remove chloride ions in the subsequent process, which is not preferable in terms of efficiency, so the chemical pickling of the present invention may be performed for 35 seconds or less.
According to the method of manufacturing a hot-rolled hot-dip galvanized steel sheet of one aspect of the present invention, mechanical descaling by shot blasting and chemical pickling by a hydrochloric acid solution are performed in a mixed manner, so that the scale can be removed in a short time as compared with the chemical pickling alone, and the amount of the acid solution used can be effectively reduced. In addition, according to the method for manufacturing a hot-rolled hot-dip galvanized steel sheet having an excellent surface appearance according to one aspect of the present invention, mechanical descaling by shot blasting and chemical pickling by a hydrochloric acid solution are combined, so that the scale remaining on the surface of the base steel sheet can be effectively removed, and the cleanliness of the surface of the base steel sheet can be effectively ensured.
Temper rolling
After mechanical descaling and chemical pickling, temper rolling can be performed by pressing the surface of the base steel sheet with a smooth roll (BrightRoll). The base steel sheet may have an average roughness of 0.1 to 0.8 μm based on a surface center line average roughness (Ra) of the smooth roll, and may be drawn at the second elongation by pressurization of the smooth roll.
The lower limit of the second elongation for securing the flatness of the surface of the base steel sheet may be 0.4% or more. However, when the second elongation is excessively large, the effect of flattening the roughness of the surface of the base steel sheet is saturated, and there are problems in deformation of the shape of the base steel sheet and hardening of the material due to excessive stretching, so the upper limit of the second elongation may be limited to 2.5%.
In the descaling, the base steel sheet is drawn at the first elongation to generate cracks in the scale on the surface of the base steel sheet, and in the temper rolling, the base steel sheet is drawn at the second elongation to secure the surface flatness of the base steel sheet. Therefore, in order to achieve an effective roughness-flattening effect, the base steel sheet may be subjected to drawing at the temper rolling with a second elongation that is greater than the first elongation at which scale is removed. This is because, when the first elongation is larger than the second elongation, it is difficult to ensure sufficient surface roughness by temper rolling due to hardening of the material generated in the scale removal.
In addition, in order to achieve surface cleanliness and flatness of roughness of the base steel sheet, the sum of the first elongation and the second elongation may be 0.7% or more. However, when the sum of the first elongation and the second elongation exceeds a predetermined level, an excessive rolling load is caused in the temper rolling mill, the roll life is shortened, and material deformation may be caused due to excessive rolling reduction, so the sum of the first elongation and the second elongation may be 4% or less.
The roughness of the surface of the base steel sheet after temper rolling may be on the level of 0.7 to 2.5 μm, based on the center line average roughness (Ra). In the initial dipping stage of the hot dip galvanizing bath, Al having high reactivity first reacts with Fe of the base steel sheet to form an Fe-Al alloy phase, so that the growth of hard Fe-Zn intermetallic compounds can be suppressed. Therefore, when the effective reaction surface area of the base steel sheet is enlarged, the growth of Fe — Zn intermetallic compounds is suppressed, contributing to the improvement of the mechanical physical properties of the plating layer, so that the plating layer can be effectively prevented from peeling. Therefore, in order to achieve such an effect, temper rolling may be performed such that the surface roughness of the steel sheet satisfies 0.7 μm or more with respect to the center line average roughness (Ra). On the other hand, when the roughness deviation of the base steel sheet is excessively large, oxidation of Al is concentrated in a region where the roughness deviation is large, so that an alumina layer may be locally formed to form an intermittent alumina layer. Therefore, in order to secure the alumina layer continuously distributed on the surface side of the plating layer, temper rolling may be performed so that the surface roughness of the steel sheet satisfies 2.5 μm or less with respect to the center line average roughness (Ra).
Hot dip galvanizing bath dip
The base steel sheet having finished the temper rolling may be immersed in a zinc-based plating bath, so that a zinc coating layer may be formed. The hot dip galvanizing bath of the present invention may include 0.2 to 0.4% by weight of Al and the balance of Zn and other unavoidable impurities. Al is an element that imparts fluidity to the plating bath and contributes to improvement of the bonding force between the galvanized layer and the base steel sheet, and thus the hot dip galvanizing bath of the present invention may contain 0.2% or more of Al. However, when the content of Al added is too high, the effect of improving the fluidity of the plating bath is saturated, and the generation of dross is increased due to promotion of the erosion of Fe, so the Al content of the hot dip galvanizing bath of the present invention may be 0.4% or less. The Al content of the hot dip galvanizing bath may be preferably 0.2 to 0.24%.
The base steel sheet of the present invention may be immersed in a hot-dip galvanizing bath at an immersion temperature of 450 to 500 ℃. When the temperature of the base steel sheet is lower than that of the hot dip galvanizing bath, the possibility of generation of flow mark defects due to the reduction in fluidity of the hot dip galvanizing bath increases, and therefore, the base steel sheet is preferably heated to a temperature higher than that of the plating bath and held and then immersed in the plating bath. Therefore, the base steel sheet of the present invention can be immersed in a hot dip galvanizing bath at an immersion temperature of 450 ℃ or higher. In addition, when the immersion temperature of the base steel sheet is higher than that of the hot-dip galvanizing bath, Fe dissolution is accelerated to increase the generation of dross, and surface defects such as dross embossed on the surface of the plated layer may be caused. Therefore, the base steel sheet of the present invention can be immersed in a hot-dip galvanizing bath at an immersion temperature of 500 ℃ or less, so that a galvanized layer can be formed on the base steel sheet.
Therefore, the hot-rolled hot-dip galvanized steel sheet of the present invention manufactured by the above manufacturing method can effectively suppress the occurrence of flow mark defects on the surface of the galvanized layer, and thus can have a beautiful surface appearance.
In addition, the above manufacturing method sequentially applies mechanical descaling and chemical pickling to the base steel sheet, and thus can effectively remove residual scale on the surface of the base steel sheet while minimizing the use of a chemical solution for chemical pickling.
Detailed Description
Hereinafter, the present invention will be described in more detail by examples. The following examples are intended to describe preferred embodiments of the present invention in more detail, and it should be noted that the scope of the present invention is not necessarily limited to the following examples.
JS-SPHC with a thickness of 3.2mm (sample 1, tensile strength of 350MPa) and JS-SAPH400 with a thickness of 2.9mm (sample 2, tensile strength of 400MPa) were selected as test samples. Although the present invention is not necessarily applied to a hot rolled steel sheet of a thick plate, a severe environment is provided for improving flow mark defects by selecting a hot rolled steel sheet having a thickness of 3 mm. The first elongation, mechanical descaling and chemical pickling described in table 1 below were applied to remove scale on the surface of the test sample, and each test sample was temper-rolled using a smooth roll having a roughness (Ra) of 0.2 μm and subjected to drawing at the second elongation. After temper rolling, degreasing and drying of the rolling oil were performed, and galvanizing was performed on the surface of the test sample. Plating was performed using a multifunctional hot dip plating simulation (Iwatani corp., Multi Functional process simulator) by the valley industry co, and hot dip galvanized samples were manufactured by setting heat treatment and plating conditions as shown in table 2 below. In the production of the hot dip galvanized samples, the temperature conditions in each section (PHS, DFF, HRS, GJS, TDS) were the same, but only the dipping temperatures of the base steel sheets were set to be different.
[ Table 1]
[ Table 2]
After the plating, air wiping was performed under the same conditions, and the results of observing the surface and plating layer of each hot dip galvanized sample are shown in table 3 below. The surface quality and the distribution range of the Al-concentrated layer, whether or not the distribution is continuous, and the maximum thickness of each sample were measured, respectively. The surface quality was evaluated by observing each sample with the naked eye, specifically, o indicates excellent (no flow mark defect or no plating was generated), and x indicates insufficient (flow mark defect or no plating was generated). After FIB (ion beam accelerator) processing, the distribution range, whether or not the Al-concentrated layer is continuously distributed, and the maximum thickness are analyzed by TEM (transmission electron microscope). In addition, the residual scale of each base steel sheet was evaluated before plating on each sample, and the results are also shown in table 3. For evaluation of residual scale of the base steel sheet, the fraction of the scale region on the Image was calculated by an Image analyzer (Image analyzer) after confirming a Scanning Electron Microscope (SEM) Image at a magnification of 200 times in a Back-scattering mode (Back-scattering mode).
[ Table 3]
In the case of examples 1 to 15 satisfying the conditions of the present invention, it was confirmed that a continuous Al-concentrated layer was formed at a depth of 100nm or less from the surface of the galvanized layer, and the maximum thickness of the Al-concentrated layer was not more than 50 nm. In the cases of examples 1 to 15, it was confirmed that the residual scale of the base steel sheet before plating was 3% or less, and excellent surface cleanliness was ensured, thereby forming a continuous Al-concentrated layer. Therefore, in the case of examples 1 to 15, it was confirmed that no flow mark defect or unplated surface defect occurred, and thus had excellent surface appearance.
On the other hand, in the case of comparative examples 1 to 15 which did not satisfy the conditions of the present invention, it was confirmed that the Al-concentrated layer was intermittently formed and the maximum thickness of the Al-concentrated layer exceeded 50 nm. That is, since the Al-concentrated layer is formed unevenly and discontinuously, zinc oxide is formed unevenly on the surface of the plated layer, and flow mark defects or surface defects of the non-plated layer occur.
Although the present invention is described above in detail by way of embodiments, other forms of embodiments are also possible. Therefore, the technical spirit and scope of the appended claims should not be limited to the above-described embodiments.
Claims (16)
1. A hot-rolled hot-dip galvanized steel sheet having excellent surface appearance, comprising:
a base steel plate; and
a zinc-plating layer is arranged on the surface of the zinc-plating layer,
wherein the galvanized layer includes a continuous Al-concentrated layer formed at a depth within 100nm from a surface of the galvanized layer.
2. The hot-rolled hot-dip galvanized steel sheet having excellent surface appearance according to claim 1, wherein,
the Al-concentrated layer is alumina (Al)2O3) And (3) a layer.
3. The hot-rolled hot-dip galvanized steel sheet having excellent surface appearance according to claim 1, wherein,
the Al-concentrated layer has a thickness of 50nm or less (excluding 0 nm).
4. The hot-rolled hot-dip galvanized steel sheet having excellent surface appearance according to claim 1, wherein,
the surface roughness of the surface of the base steel sheet forming the interface with the zinc plating layer is 0.7 to 2.5 [ mu ] m based on the center line average roughness (Ra).
5. The hot-rolled hot-dip galvanized steel sheet having excellent surface appearance according to claim 1, wherein,
the zinc plating layer contains 0.2 to 0.6% by weight of Al and the balance of Zn and other unavoidable impurities.
6. A method of manufacturing a hot-rolled hot-dip galvanized steel sheet having excellent surface appearance, comprising:
drawing a base steel sheet at a first elongation to generate cracks in a scale on a surface of the base steel sheet;
applying physical impact to the surface of the base steel plate, and mechanically removing an oxide skin on the surface of the base steel plate;
reacting the surface of the base steel plate with an acidic solution to chemically pickle the surface of the base steel plate;
temper rolling the base steel plate at a second elongation to flatten the surface of the base steel plate; and
the base steel sheet is immersed in a hot dip galvanizing bath containing, in wt%, 0.2% to 0.4% of Al and the balance of Zn and other unavoidable impurities to form a galvanized layer.
7. The method for manufacturing a hot-rolled hot-dip galvanized steel sheet having excellent surface appearance according to claim 6, wherein,
the first elongation is 0.2-1.5%.
8. The method for manufacturing a hot-rolled hot-dip galvanized steel sheet having excellent surface appearance according to claim 6, wherein,
and performing shot blasting treatment on the surface of the base steel plate, and mechanically removing the oxide skin on the surface of the base steel plate.
9. The method for manufacturing a hot-rolled hot-dip galvanized steel sheet having excellent surface appearance according to claim 6, wherein,
the shot blasting process projects shots with an average diameter of 0.18mm to 0.6mm at an average projection amount of 800kg/min to 1800kg/min and an average projection speed of 65m/s to 90 m/s.
10. The method for manufacturing a hot-rolled hot-dip galvanized steel sheet having excellent surface appearance according to claim 6, wherein,
immersing the base steel plate in a hydrochloric acid solution with the temperature range of 70-85 ℃ and the concentration of 5-20% for 15-35 seconds, and chemically pickling the surface of the base steel plate.
11. The method for manufacturing a hot-rolled hot-dip galvanized steel sheet having excellent surface appearance according to claim 6, wherein,
the base steel plate is subjected to temper rolling by smooth rolls, and the surface roughness of the smooth rolls is 0.1-0.8 mu m on the basis of the center line average roughness (Ra).
12. The method for manufacturing a hot-rolled hot-dip galvanized steel sheet having excellent surface appearance according to claim 6, wherein,
the roughness of the surface of the base steel sheet after temper rolling is 0.7 to 2.5 μm on the basis of the center line average roughness (Ra).
13. The method for manufacturing a hot-rolled hot-dip galvanized steel sheet having excellent surface appearance according to claim 6, wherein,
the second elongation is 0.5% -2.5%.
14. The method for manufacturing a hot-rolled hot-dip galvanized steel sheet having excellent surface appearance according to claim 6, wherein,
the sum of the first elongation and the second elongation is 0.7-4.0%.
15. The method for manufacturing a hot-rolled hot-dip galvanized steel sheet having excellent surface appearance according to claim 6, wherein,
the second elongation is greater than the first elongation.
16. The method for manufacturing a hot-rolled hot-dip galvanized steel sheet having excellent surface appearance according to claim 6, wherein,
the dipping temperature of the hot dip galvanizing bath of the base steel plate is 450-500 ℃.
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| KR1020170180298A KR102031463B1 (en) | 2017-12-26 | 2017-12-26 | Hot-dip galvanized hot rolled steel sheet having excellent surface appearance and manufacturing method for the same |
| PCT/KR2018/015366 WO2019132293A1 (en) | 2017-12-26 | 2018-12-06 | Hot dip galvanized steel sheet having excellent surface appearance, and manufacturing method therefor |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| KR20140001557A (en) * | 2012-06-27 | 2014-01-07 | 주식회사 포스코 | Method for manufacturing alloy plated steel sheet having excellent surface appearance |
| KR20150051840A (en) * | 2013-11-05 | 2015-05-13 | 주식회사 포스코 | HOT DIP Zn-Al-Mg ALLOY PLATED STEEL SHEET HAVING EXCELLENT FORMABILITY AND ADHESION PROPERTY AND METHOD FOR MANUFACTURING THE SAME |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| KR20010060423A (en) | 1999-12-22 | 2001-07-07 | 이구택 | a method of manufacturing a hot dip galvanized steel sheets with excellent surface appearance |
| KR101289198B1 (en) * | 2011-06-28 | 2013-07-26 | 주식회사 포스코 | Plated steel sheet for hot press forming having superior stability of plating layer |
| KR101568509B1 (en) * | 2013-12-21 | 2015-11-20 | 주식회사 포스코 | HOT DIP Zn-Al-Mg ALLOY PLATED STEEL SHEET HAVING EXCELLENT CORROSION RESISTANCE AND METHOD FOR MANUFACTURING THE SAME |
| KR20160073493A (en) * | 2014-12-16 | 2016-06-27 | 주식회사 포스코 | Method for manufacturing of galvanized steel sheet to improve an elogation and galvanized steel sheet manufactured thereby |
| KR101647223B1 (en) * | 2014-12-23 | 2016-08-10 | 주식회사 포스코 | Method for manufacturing high strength galvanized steel sheet having excellent surface property and coating adhesion |
-
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20140001557A (en) * | 2012-06-27 | 2014-01-07 | 주식회사 포스코 | Method for manufacturing alloy plated steel sheet having excellent surface appearance |
| KR20150051840A (en) * | 2013-11-05 | 2015-05-13 | 주식회사 포스코 | HOT DIP Zn-Al-Mg ALLOY PLATED STEEL SHEET HAVING EXCELLENT FORMABILITY AND ADHESION PROPERTY AND METHOD FOR MANUFACTURING THE SAME |
Non-Patent Citations (2)
| Title |
|---|
| E. BIBER: "Scanning auger microprobe study of hot-dipped regular-spangle galvanized steel: Part I. surface composition of As-produced sheet", 《METALLURGICAL AND MATERIALS TRANSACTIONS. A》 * |
| 张启富主编: "《现代钢带连续热镀锌》", 31 January 2007, 冶金工业出版社 * |
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