WO2008078912A9 - Zn-coated steel sheet having excellent surface quality and the method for manufacturing the same - Google Patents
Zn-coated steel sheet having excellent surface quality and the method for manufacturing the sameInfo
- Publication number
- WO2008078912A9 WO2008078912A9 PCT/KR2007/006716 KR2007006716W WO2008078912A9 WO 2008078912 A9 WO2008078912 A9 WO 2008078912A9 KR 2007006716 W KR2007006716 W KR 2007006716W WO 2008078912 A9 WO2008078912 A9 WO 2008078912A9
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- steel sheet
- steel
- coated steel
- temperature
- amount
- Prior art date
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 116
- 239000010959 steel Substances 0.000 title claims abstract description 116
- 238000000034 method Methods 0.000 title claims description 25
- 238000004519 manufacturing process Methods 0.000 title claims description 16
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 24
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 21
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 16
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 7
- 239000012535 impurity Substances 0.000 claims abstract description 6
- 238000000137 annealing Methods 0.000 claims description 16
- 238000005098 hot rolling Methods 0.000 claims description 9
- 229910052684 Cerium Inorganic materials 0.000 claims description 8
- 229910052746 lanthanum Inorganic materials 0.000 claims description 8
- 229910052758 niobium Inorganic materials 0.000 claims description 8
- 229910052719 titanium Inorganic materials 0.000 claims description 8
- 238000005097 cold rolling Methods 0.000 claims description 7
- 229910052791 calcium Inorganic materials 0.000 claims description 4
- 238000005554 pickling Methods 0.000 claims description 4
- 229910052750 molybdenum Inorganic materials 0.000 claims description 3
- 238000003303 reheating Methods 0.000 claims description 3
- 229910052726 zirconium Inorganic materials 0.000 claims description 3
- 239000011248 coating agent Substances 0.000 abstract description 21
- 238000000576 coating method Methods 0.000 abstract description 21
- 229910052698 phosphorus Inorganic materials 0.000 abstract description 3
- 230000000694 effects Effects 0.000 description 35
- 239000010410 layer Substances 0.000 description 11
- 230000007547 defect Effects 0.000 description 10
- 229910052751 metal Inorganic materials 0.000 description 9
- 239000002184 metal Substances 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 7
- 239000011575 calcium Substances 0.000 description 6
- 230000003647 oxidation Effects 0.000 description 6
- 238000007254 oxidation reaction Methods 0.000 description 6
- 239000006104 solid solution Substances 0.000 description 6
- 238000005728 strengthening Methods 0.000 description 6
- 238000003466 welding Methods 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 230000009466 transformation Effects 0.000 description 5
- 229910001566 austenite Inorganic materials 0.000 description 4
- 230000003247 decreasing effect Effects 0.000 description 4
- 210000001787 dendrite Anatomy 0.000 description 4
- 230000001976 improved effect Effects 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 239000011247 coating layer Substances 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 238000005275 alloying Methods 0.000 description 2
- 238000005279 austempering Methods 0.000 description 2
- 239000010960 cold rolled steel Substances 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 229910052711 selenium Inorganic materials 0.000 description 2
- 229910052718 tin Inorganic materials 0.000 description 2
- 229910052727 yttrium Inorganic materials 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- 239000002390 adhesive tape Substances 0.000 description 1
- 229910052787 antimony Inorganic materials 0.000 description 1
- 229910001563 bainite Inorganic materials 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000003618 dip coating Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000005246 galvanizing Methods 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910000734 martensite Inorganic materials 0.000 description 1
- 150000001247 metal acetylides Chemical class 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Classifications
-
- 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
- C22C38/002—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
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
Definitions
- the present invention relates to a high strength thin steel sheet generally used for an inner panel or outer panel of an automobile, and more particularly, to a Zn-coated steel sheet with more excellent formability than that of a conventional high strength steel and an excellent surface quality in a process of manufacturing a high strength steel sheet and a method of manufacturing the same.
- a steel sheet is manufactured by adding Si, Mn, Ti, Nb, and Al, which are elements strengthening material quality. Most of elements are more easily oxidized than Fe, which cause a surface concentration of oxide in a cold annealing process.
- An aspect of the present invention provides a Zn-coated steel sheet having fine surface qualities by appropriately controlling alloy elements and a hot coiling temperature of steel in a high strength thin steel sheet with excellent workability and a method of manufacturing the Zn-coated steel sheet.
- a Zn-coated steel sheet with excellent surface quality including, by weight percent, C: 0.04 to 0.25%, Mn: 0.2 to 2.5%, Si: 0.01 to 1.7%, Al: 0.01 to 1.5%, R 0.01 to 0.1%, S: 0.02% or less, and Sb: 0.001 to 0.1%, residual Fe, and unavoidable impurities, wherein the Si and Al satisfy 0.5 ⁇ Si+Al ⁇ 2.0 and a thickness of an oxide layer on a surface thereof is 1 /M or less.
- a method of manufacturing a Zn-coated steel sheet with excellent surface quality including: reheating and hot rolling a steel slab at a temperature from 1100 to 125O 0 C, the steel slab including, by weight percent, C: 0.04 to 0.25%, Mn: 0.2 to 2.5%, Si: 0.01 to 1.7%, Al: 0.01 to 1.5%, R 0.01 to 0.1%, S: 0.02% or less, and Sb: 0.001 to 0.1%, residual Fe, and unavoidable impurities, in which the Si and Al satisfy 0.5 ⁇ Si+Al ⁇ 2.0; coiling the steel slab at a temperature from 450 to 75O 0 C; pickling and cold rolling the steel slab; and annealing the steel slab at a temperature within a range from 700 to 86O 0 C.
- FIG. 1 is a graph illustrating distribution of some metal elements of oxides on a surface for each type of steel according to whether Sb is added or not;
- FIG. 2 illustrates photographs illustrating a size of surface oxides for each type of steels according to whether Sb is added or not;
- FIG. 3 illustrates photographs illustrating a size of surface oxides for each type of steels according to a hot rolling and coiling temperature
- FIG. 4 illustrates photographs illustrating an external shape of Zn-coating for each type of steels according to whether Sb is added or not.
- the present invention is provided based on a result of research that coated surface may be improved by properly controlling alloy elements of steel and a hot coiling temperature while researching a method of improving the coated surface quality in a high strength steel sheet with excellent workability.
- An amount of C may be 0.04 to 0.25%
- C in steel is concentrated on austenite while two phase regions annealing and rapid cooling and austempering bainite reverse, thereby lowering a transformation temperature of martensite in austenite.
- the amount is less than 0.04%, since grains are grown and a solid solution strengthening effect and precipitation strengthening effect due to C are reduced, it may be difficult to provide enough tensile strength.
- the amount of C may be limited to be from 0.04 to 0.25%.
- An amount of Mn may be from 0.2 to 2.5%.
- Mn has an effect on solid solution strengthening. When the amount of Mn is less than 0.2%, the effect is insignificant. When more than 2.5%, strength of steel is greatly increased due to excessively high hardenability, workability may be decreased and welding characteristics of the steel may be deteriorated. Accordingly, the amount of Mn may be limited to be from 0.2 to 2.5%.
- An amount of Si may be from 0.01 to 1.7%.
- Si in steel is capable of increasing strength of the steel without decrease of malleability and may be added to 0.01% or more to provide strength.
- Si oxide is concentrated on a surface of a steel sheet in annealing at a high temperature in a continuous annealing process and this oxide reduces the wettability of Zn on the surface of the steel sheet during a continuous hot-dip galvanizing process. And also welding characteristics of the steel may be greatly deteriorated by the high amount of Si in the steel.
- An amount of Al may be from 0.01 to 1.5%.
- Al is added to improve malleability. Al is added to suppress a formation of carbides formed in an austempering process and to improve strength. When the amount is less than 0.01%, it is difficult to obtain the effect. When more than 1.5%, internal oxidation is increased in annealing a cold rolled steel sheet in such a way that an alloying process of GA coating is prevented and a high alloying temperature is required. Accordingly, the amount of Al may be limited to be from 0.01 to 1.5%.
- An amount of P may be from 0.01 to 0.1 % .
- P in steel is a representative solid solution element added to improve strength, together with Mn.
- the amount is less than 0.01%, it is difficult to obtain an effect.
- welding characteristics may be deteriorated and a material deviation for each portion of steel may be increased due to central segregation occurring in continuous casting.
- An amount of S may be from 0.02% or less.
- S in steel is an element unavoidably added to manufacture the steel.
- An upper limit of the amount may be limited to be 0.02% or less.
- An amount of Sb may be from 0.001 to 0.1 % .
- Sb is most important element in the present invention. Though Sb itself does not form an oxide layer at a high temperature, a diffusion of elements in steel is suppressed, thereby suppressing a formation of oxides. Also, Sb has a notable effect on suppressing selective oxidation growing along a grain boundary of a steel sheet. Adding Sb suppresses penetration of various oxides formed along the grain boundary of the surface of the steel sheet in a hot rolling process, which is caused by a large amount of Si, Mn, and Al.
- a depth of the oxides on the grain boundary of the hot rolled steel sheet is more than 1 ⁇ m, residual oxides in a metal after pickling causes various scale defects in a next cold rolling process. Accordingly, it is important to control the depth of the oxides on the grain boundary of the hot rolled steel sheet.
- the suppressing the selective oxidation of the boundary of the hot rolled steel sheet by adding Sb has a great effect on suppressing the scale defects.
- the adding Sb improves coating properties by suppressing the formation of the oxides in the annealing process due to the large amount of Si, Mn, and Al, and more particularly, effectively suppresses coarsening of the oxide layer on the surface when Mn and B are compositely added.
- the oxides When annealed oxides coarsely grow, the oxides are repeatedly stacked on a roll and cause dents on a surface of a cold rolled material or a coating material.
- the suppressing the oxides on the surface by adding Sb has a great effect on suppressing the dents.
- 2 2 3 oxides may be coarsened.
- Si and Al may satisfy 0.5 ⁇ Si+Al ⁇ 2.0.
- the sum of Si and Al may be limited to be from 0.5 to 2.0wt%.
- the steel sheet including the elements further includes one or more of Go: 0.01 to 1.0%, B: 0.0002 to 0.002%, Zr: 0.0005 to 0.1%, Ti: 0.001 to 0.1%, Nb: 0.001 to 0.1%, La: 0.0005 to 0.040%, Mo: 0.005 to 0.5%, Ce: 0.0005 to 0.040%, and Ca: 0.0005 to 0.030%.
- An amount of Oo may be from 0.01 to 1.0%.
- Go in steel is added to improve strength of the steel. Since suppressing a formation of oxides in annealing at a high temperature, wettability of a steel sheet in a continuous hot- dip coating process may be improved. To obtain the effect, the amount should be 0.01% or more. However, when Go is added more than a certain limit, an elongation rate of the steel is greatly reduced. Accordingly, an upper limit may be 1.0%.
- An amount of B may be from 0.0002 to 0.002% .
- [62] B in steel improves fatigue properties of a spot welding part and prevents brittleness of a P grain boundary. Also, in a process of manufacturing steel containing a large amount of Al and Si, there is an effect of improving high temperature malleability. To obtain the effect, the amount should be 0.0002% or more. However, when more than 0.002%, workability is rapidly decreased and surface properties are deteriorated. Accordingly, the amount may be limited to be from 0.0002 to 0.002%.
- An amount of Zr may be from 0.0005 to 0.1%.
- Zr in steel is in a solid solution with a grain boundary of columnar dendrites and increases a melting temperature of a low melting point compound in which Al is concentrated, thereby preventing a liquid film at a temperature of 1300 0 C or less and strengthening the grain boundary of the columnar dendrites.
- the amount is less than 0.0005%, it is difficult to provide the effect.
- the amount is more than 0.1%, it is difficult to provide more improved effect. Accordingly, the amount may be limited to be from 0.0005 to 0.1%.
- Amounts of Ti and Nb may be from 0.001 to 0.1%, respectively.
- Ti and Nb in steel have an effect on increasing strength of a steel sheet and grain size refinement.
- the amounts of the Ti and Nb are less than 0.001%, it is difficult to provide the effect.
- the amounts are more than 0.1%, due to an increase of manufacturing costs and an excessive amount of precipitates, malleability of ferrites may be decreased. Accordingly, the respective amounts may be United to be from 0.001 to 0.1%.
- Amounts of La and Ce may be from 0.0005 to 0.04%, respectively.
- La and Ce in steel reduce a size and amount of columnar dendrites causing brittleness of a grain boundary and increases an amount of equiaxed dendrites having excellent high temperature malleability in such a way that hot workability of a cast structure.
- La and Ce reduce a bad effect of P and S, which are segregated from the grain boundary and decrease fracture strength of the grain boundary, by forming a compound of P and S.
- the amounts of La and Ce are less than 0.0005%, respectively, there is no effect. When the amounts are more than 0.04%, there is no more than the effect. Accordingly, the respective amounts of La and Ce may be limited from 0.0005 to 0.04%.
- An amount of Mo may be from 0.005 to 0.5%.
- Mo in steel is added to improve work brittleness and coating properties.
- amount is less than 0.005%, a predetermined effect is not shown.
- amount is more than 0.05%, not only the effect is greatly decreased but also it is economically disadvantageous.
- the amount may be limited to be from 0.005 to 0.05%.
- An amount of Ca may be from 0.0005 to 0.03%.
- Calcium Ca forms a compound together with a non-metallic inclusion such as MnO, and MnS in a molten steel to spherodize the non-metallic inclusion. This accordingly increases rupture strength of the columnar grains, allows the steel sheet to be less prone to the flange crack and increases bore expandability. However, the Ca amount exceeding 0.03% yields no further effect. Thus Ca may be added in an amount of 0.0005 to 0.030%.
- a thickness of an oxide layer on a surface of a steel sheet is limited to be 1 ⁇ m or less.
- the oxide layer formed on a surface of a metal by an annealing process after cold rolling acts as an obstacle between a steel and a coating layer, which obstructs coating adhesion.
- the oxide layer grows to have a thickness more than 1 ⁇ m, dents and coating defects occur due to separation of oxides. Accordingly, it is advantageous for providing quality of the coating layer that the oxide layer is uniformly formed.
- 0.005 to 0.1% of Sb is added and concentrated on a surface of a metal instead of being oxidized in such a way that oxidation is suppressed, thereby forming the oxide layer uniformly and suppressing the thickness thereof to be 1 ⁇ m or less.
- a steel slab including the composition described above is reheated at a temperature of 1100 to 125O 0 C.
- the temperature is less than 1100 0 C, structure equalization and re-solid solution of Ti and Nb are not enough.
- the temperature is more than 125O 0 C, a large amount of oxides such as SiO , MnO, and Al O are formed at an
- the reheating temperature may be limited to be from 1100 to 125O 0 C.
- finish hot rolling is performed at a temperature from Ar transformation point to 95O 0 C.
- a temperature of the finish hot rolling is less than the Ar transformation point, hot transformation resistance may be rapidly increased and manufacturing defects may occur.
- the temperature is more than 95O 0 C, not only excessively thick oxide scales may occur but also the steel sheet may be coarsened. Accordingly, the finish hot rolling temperature may be limited to be from the Ar transformation point to 95O 0 C.
- the steel slab is coiled at a temperature from 450 to
- a limitation of the coiling temperature is very important to embody the effect of adding Sb in the present invention.
- Si, Mn, and Al in steel could react to oxide scales of FeO after the coiling and form oxides at an interface between scales and a metal. It has a great effect on concentration of elements in a top surface metal layer whether the oxides of Si, Mn, and Al.
- the hot coiling temperature may be limited to be from 450 to 75O 0 C.
- a hot rolled steel sheet formed by the described process is pickled, cold rolled at a target thickness, and annealed at a temperature from 700 to 86O 0 C to remove recys- tallization and nicrostructure defects.
- the annealing temperature is less than 700 0 C, since development of annealed oxides is small, the effect of adding Sb is not distinguishable.
- the temperature is more than 86O 0 C, since oxides are excessively grown, it is impossible to suppress surface oxides enough by adding Sb.
- a steel slab having a composition as shown in following Table 1 was extracted from heating furnace at a temperature of 1200 0 C, coiled at a temperature shown in Table 2, and cold rolled, thereby manufacturing a steel sheet.
- FIG. 1 illustrates distribution of surface oxides of inventive steels 7, 8, and 15 according to whether Sb is added or not. That is, it may be checked that relative amounts of Mn and Al concentrated on a surface by adding Sb are reduced.
- FIG. 2 illustrates shapes of oxides formed on a surface of cold rolling steel sheet of inventive steel 1 and comparative steel 7 according to whether Sb is added or not.
- FIG. 2 (a) illustrates the inventive steel 1 and (b) illustrates the comparative steel 7.
- FIG. 2 in the case of Sb-added steel, it may be known that a grain size of surface oxides is notably reduced.
- FIG. 4 photographs illustrating ungalvanized bare spots occurring in Sb- added steel (inventive steel 5) and non-Sb steel (comparative steel 6).
- the inventive steel 5 is shown in (a) of FIG. 4
- the comparative steel 6 is shown in (b) of FIG. 4.
- FIG. 4 in the case of the non-Sb steel, a probability of occurrence of ungalvanized bare spots is high.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Sheet Steel (AREA)
- Coating With Molten Metal (AREA)
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP07851682A EP2097546A1 (en) | 2006-12-27 | 2007-12-21 | Zn-coated steel sheet having excellent surface quality and the method for manufacturing the same |
JP2009528185A JP5648237B2 (en) | 2006-12-27 | 2007-12-21 | Galvanized steel sheet with excellent surface quality and manufacturing method thereof |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
KR10-2006-0135657 | 2006-12-27 | ||
KR1020060135657A KR20080060981A (en) | 2006-12-27 | 2006-12-27 | Zn-coated steel sheet having excellent surface quality and the method for manufacturing the same |
Publications (2)
Publication Number | Publication Date |
---|---|
WO2008078912A1 WO2008078912A1 (en) | 2008-07-03 |
WO2008078912A9 true WO2008078912A9 (en) | 2008-10-23 |
Family
ID=39562668
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/KR2007/006716 WO2008078912A1 (en) | 2006-12-27 | 2007-12-21 | Zn-coated steel sheet having excellent surface quality and the method for manufacturing the same |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP2097546A1 (en) |
JP (1) | JP5648237B2 (en) |
KR (1) | KR20080060981A (en) |
CN (1) | CN101460642A (en) |
WO (1) | WO2008078912A1 (en) |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP5862002B2 (en) * | 2010-09-30 | 2016-02-16 | Jfeスチール株式会社 | High-strength hot-dip galvanized steel sheet with excellent fatigue characteristics and method for producing the same |
US10082032B2 (en) | 2012-11-06 | 2018-09-25 | Howmet Corporation | Casting method, apparatus, and product |
CN103882202B (en) * | 2012-12-20 | 2016-03-30 | 上海梅山钢铁股份有限公司 | The manufacture method of the high-strength hot-galvanized steel of a kind of continuous annealing |
KR102140811B1 (en) | 2013-07-23 | 2020-08-03 | 삼성전자주식회사 | User Interface Providing Method for Device and Device Thereof |
JP6056745B2 (en) * | 2013-12-12 | 2017-01-11 | Jfeスチール株式会社 | High formability and high strength cold-rolled steel sheet excellent in chemical conversion treatment and production method thereof |
KR101630976B1 (en) * | 2014-12-08 | 2016-06-16 | 주식회사 포스코 | Ultra-high strenth galvanized steel sheet having excellent surface and coating adheision and method for manufacturing thereof |
KR101639914B1 (en) * | 2014-12-23 | 2016-07-15 | 주식회사 포스코 | High strength cold steel sheet with good phosphating property and method for manufacturing the same |
KR102046544B1 (en) | 2015-04-15 | 2019-11-19 | 닛폰세이테츠 가부시키가이샤 | Hot rolled steel sheet and manufacturing method |
KR101726094B1 (en) * | 2015-12-24 | 2017-04-12 | 주식회사 포스코 | Hot pressed part with reduced microcrack and method for manufacturing same |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3951282B2 (en) * | 2000-01-28 | 2007-08-01 | Jfeスチール株式会社 | Hot-dip galvanized steel sheet and manufacturing method thereof |
JP3809074B2 (en) * | 2001-03-30 | 2006-08-16 | 新日本製鐵株式会社 | High-strength hot-dip galvanized steel sheet with excellent plating adhesion and press formability and method for producing the same |
JP4718682B2 (en) * | 2000-12-29 | 2011-07-06 | 新日本製鐵株式会社 | High-strength galvannealed steel sheet and high-strength hot-dip galvanized steel sheet excellent in plating adhesion and press formability and manufacturing method thereof |
JP2002249846A (en) * | 2001-02-23 | 2002-09-06 | Kawasaki Steel Corp | Steel having excellent pitting resistance |
JP4288085B2 (en) * | 2003-02-13 | 2009-07-01 | 新日本製鐵株式会社 | Hot-dip galvanized high-strength steel sheet excellent in hole expansibility and method for producing the same |
JP4561200B2 (en) * | 2004-06-30 | 2010-10-13 | Jfeスチール株式会社 | High-strength cold-rolled steel sheet with excellent secondary work brittleness resistance and manufacturing method thereof |
JP2006274288A (en) * | 2005-03-28 | 2006-10-12 | Jfe Steel Kk | High strength hot dip galvanized steel sheet having excellent surface appearance |
-
2006
- 2006-12-27 KR KR1020060135657A patent/KR20080060981A/en not_active Application Discontinuation
-
2007
- 2007-12-21 WO PCT/KR2007/006716 patent/WO2008078912A1/en active Application Filing
- 2007-12-21 JP JP2009528185A patent/JP5648237B2/en not_active Expired - Fee Related
- 2007-12-21 EP EP07851682A patent/EP2097546A1/en not_active Withdrawn
- 2007-12-21 CN CNA2007800202270A patent/CN101460642A/en active Pending
Also Published As
Publication number | Publication date |
---|---|
CN101460642A (en) | 2009-06-17 |
JP5648237B2 (en) | 2015-01-07 |
KR20080060981A (en) | 2008-07-02 |
JP2010503769A (en) | 2010-02-04 |
EP2097546A1 (en) | 2009-09-09 |
WO2008078912A1 (en) | 2008-07-03 |
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