CN101772584B - High-strength steel sheet - Google Patents
High-strength steel sheet Download PDFInfo
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- CN101772584B CN101772584B CN2008801012051A CN200880101205A CN101772584B CN 101772584 B CN101772584 B CN 101772584B CN 2008801012051 A CN2008801012051 A CN 2008801012051A CN 200880101205 A CN200880101205 A CN 200880101205A CN 101772584 B CN101772584 B CN 101772584B
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- 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
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
- C21D8/0421—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the working steps
- C21D8/0426—Hot rolling
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- 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
- C21D9/48—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals deep-drawing sheets
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- 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
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- 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
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
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- 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
- C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
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- 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
- C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium with vanadium
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- 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
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/004—Dispersions; Precipitations
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/005—Ferrite
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- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
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Abstract
The invention provides a high-strength steel sheet excellent in stretch-flange characteristics after working and in corrosion resistance after coating. A steel sheet which has a composition containing by mass C: 0.02 to 0.20%, Si: 0.3% or below, Mn: 0.5 to 2.5%, P: 0.06% or below, S: 0.01% or below, Al: 0.1% or below, Ti: 0.05 to 0.25%, and V: 0.05 to 0.25% with the balance consisting of Fe and unavoidable impurities and a substantially ferrite single-phase structure wherein the contents of Ti, V, and solid-soluted V in precipitates of less than 20nm in size are 200 to 1750 mass ppm, 150 to 1750 mass ppm, and 200 to less than 1750 mass ppm respectively.
Description
Technical field
The stretch flange formability characteristic after the present invention relates to process and the high tensile steel plate of the excellent corrosion resistance after the application.
Background technology
The chassis of automobile (chassis), truck need possess plasticity (mainly being unit elongation and stretch flange formability characteristic) with parts such as vehicle frames, thereby use the steel of tensile strength as the 590MPa level in the past always.But, in recent years,, advancing the high strength of automotive sheet from the minimizing carrying capacity of environment of automobile and the viewpoint that improves impact characteristics, beginning tensile strength is that the use of the steel of 780MPa level is studied.
In general, the processibility of ferrous materials rises along with intensity and reduces.Therefore, begun research for steel plate with HS and high working property.As the technology that unit elongation and stretch flange formability characteristic are improved, can enumerate for example patent documentation 1～6.
Patent documentation 1 discloses and has related to the technology that tensile strength is the high-tensile steel of the above excellent processability of 590MPa, and said steel plate is characterised in that, is essentially the ferritic single phase structure, contains median size and disperses to separate out less than the Ti of 10nm and the carbide of Mo.
Patent documentation 2 discloses the technology that relates to the high tensile hot rolled steel sheet with the yield ratio more than the above intensity of 880MPa and 0.80; This steel plate in mass; Contain C:0.08～0.20%, Si:0.001% above and less than 0.2%, Mn: greater than 1.0% and below 3.0%, Al:0.001～0.5%, V: greater than 0.1% and below 0.5%, more than the Ti:0.05% and, and satisfy following 3 formulas less than 0.2% and Nb:0.005%～0.5%:
(formula 1) (Ti/48+Nb/93) * C/12≤4.5 * 10
-5,
(formula 2) 0.5≤(V/51+Ti/48+Nb/93)/(C/12)≤1.5,
(formula 3) V+Ti * 2+Nb * 1.4+C * 2+Mn * 0.1 >=0.80,
Surplus is made up of Fe and unavoidable impurities, and has the structure of steel that contains more than the ferritic 70 volume %, and said ferritic median size is below the 5 μ m and hardness is more than the 250Hv.
Patent documentation 3 discloses the technology that relates to hot-rolled steel sheet; Said steel plate is characterised in that; In mass, contain C:0.05～0.2%, Si:0.001%～3.0%, Mn:0.5～3.0%, P:0.001～0.2%, Al:0.001～3%, V: greater than 0.1% and below 1.5%, surplus is made up of Fe and impurity; Tissue is a principal phase with the ferritic of median size 1～5 μ m, and in ferrite crystal grain, to have median size be the carbonitride of the V below the 50nm.
Disclose in the patent documentation 4 and made carbide in structure of steel, separate out the high-strength steel sheet of the good heat stability that forms.This steel-sheet is characterised in that carbide has the NaCl type crystal structure of representing with MC when metallic element is designated as M, and metallic element M is made up of the metal more than 2 kinds, and these metals more than 2 kinds superstructure that formation rule is arranged in lattice.
Hot-rolled steel sheet below patent documentation 5 discloses.Composition consists of: in quality %; Contain C:0.0002～0.25%, Si:0.003～3.0%, Mn:0.003～3.0% and Al:0.002～2.0%, surplus is made up of Fe and unavoidable impurities, and the P in the impurity is below 0.15%; S is below 0.05%, and N is below 0.01%.And, in area ratio, metal structure be ferritic phase more than 70%, its average crystallite particle diameter is below the 20 μ m, length-to-diameter ratio is below 3.And, the constituting by high-angle boundary more than 70% of ferritic crystal boundary, in the ferritic phase that the high-angle boundary place forms, the area ratio that maximum diameter is below the 30 μ m, minimum diameter is the above precipitate of 5nm is below 2% of metal structure.And except that ferritic phase and precipitate, the average crystallite particle diameter of second phase that the middle mutually area ratio of residue is maximum is below the 20 μ m, and between the second nearest phase, has the high-angle boundary of ferritic phase.
But patent documentation 6 discloses deburring (burring) high-strength steel sheet of the good pull and stretch of shape freezing property; It is characterized in that; Coating has the compsn of lubricant effect on steel plate, and said steel plate contains C:0.01～0.1%, S≤0.03%, N≤0.005%, Ti:0.05～0.5% in quality %; And contain Ti in the scope that satisfies Ti-48/12C-48/14N-48/32S>=0%; Surplus is made up of Fe and unavoidable impurities, 1/2 place's plate face of thickness of slab at least 100}<011 >～MV of the X ray random strength ratio of 223}<110>orientation group is more than 3, and; { 554}<225 >, { 111}<112>and { MV of the X ray random strength ratio in<110>3 orientation of 111} is below 3.5, and the arithmetic average roughness Ra of the surface of steel plate of at least one side is 1～3.5.
Patent documentation 1: No. 3591502 communique of Japanese Patent
Patent documentation 2: TOHKEMY 2006-161112 communique
Patent documentation 3: TOHKEMY 2004-143518 communique
Patent documentation 4: TOHKEMY 2003-321740 communique
Patent documentation 5: TOHKEMY 2003-293083 communique
Patent documentation 6: TOHKEMY 2003-160836 communique
Summary of the invention
But, in above-mentioned prior art, have following problem.
In patent documentation 1 and 4, owing to contain Mo, therefore consider the skyrocketing of the prices of raw and semifnished materials of Mo in recent years, there is the problem that causes cost significantly to increase.
And along with the propelling of automobile industry globalization, the steel plate that is used for automobile begins under harsh corrosive environment, to use, erosion resistance after the application that therefore need be higher for steel plate.Relative therewith, the chemical conversion crystalline generates or growth because the interpolation of Mo can hinder, therefore make the application of steel plate after erosion resistance reduce, can not satisfy above-mentioned requirements.That is,, can not be met erosion resistance after the application that automobile industry in recent years requires through the steel of record in patent documentation 1 and the patent documentation 4.
On the other hand; Because the progress of stamping technology in recent years; Therefore begin employing and draw (pull and stretch and stretch forming) → perforation (punching) → flange shaping (reaming) such manufacturing procedure; At the stretch flange formability position of the steel plate that is shaped through such manufacturing procedure, need the stretch flange formability characteristic after pull and stretch/perforation afterwards, is promptly processed.But, in patent documentation 2,3,4,, then may not necessarily access the stretch flange formability characteristic after the sufficient processing if expect the TS that 780MPa is above.The Nb that adds in the patent documentation 3, the effect of the austenite recrystallization after the inhibition hot rolling is big.Therefore, making residually in the steel plate has non-recrystallization crystal grain, thereby has the problem that processibility is reduced.And, the problem that exists the rolling load when making hot rolling to increase.
Ferritic single-phase steel plate that tensile strength TS reaches 422MPa is disclosed in the patent documentation 5 (for example; Table 8, the test number 45 of the table 6 of embodiment, test number 1 to 5 and embodiment) with by tensile strength TS be the complex tissue steel plate (for example, embodiment table 6, test number 33 to 36 and embodiment table 8, test number 49) that the ferritic phase and second more than the 780MPa constitutes mutually.The steel plate of these patent documentations 5 mainly is the solution strengthening that effectively utilized Si or Mn to be strengthened with second mutually the phase-change organization that has utilized hard.Therefore, need steel plate be finished to be cooled to 600～800 ℃ TR with interior with the 30 ℃/average cooling rate more than the s in back 2 seconds in finish to gauge, then behind 3～15 seconds air cooling,, and batch further with the average cooling rate water-cooled more than 30 ℃/second.Thus, two during ferrite transformation is separated and obtains promoting, the tissue of steel plate becomes the ferritic phase and second mutually the complex tissue.And finishing temperature is set at (Ae3 point+100 ℃)～Ae3 point, be than think after the manufacturing the stated low TR of preferred temperature range when of the present invention.For example, be that finishing temperature is 871 ℃～800 ℃ in the complex tissue steel plate (table 6 of embodiment, test number 33 to 36) more than the 780MPa at tensile strength TS.When finishing temperature was hanged down, the solid solubility limit of the carbide forming elements such as Ti of austenite in mutually reduced, and through utilizing rolling processing to import nucleation site, therefore generated the above precipitate of 20nm.This phenomenon is called strain inducing and separates out.In the steel plate and method of manufacture of patent documentation 5, because taking place, strain inducing separates out, the growing amount that therefore is of a size of the above precipitate of 20nm increases.
And, disclose the C content of forming through a large amount of reduction steel in the patent documentation 5 and reduced the technology (reference: the table 2 of embodiment, steel numbering system AA to AE) that realizes the manufacturing of ferritic single phase structure as the content of the Mn of austenite stabilizer element.But at this moment, owing to the content of while as the Mn of solution strengthening element reduces, so the solution strengthening amount reduces.And because C content reduces, therefore the amount of separating out to the carbide of the effective Ti of precipitation strength, Nb etc. reduces, and the precipitation strength amount also reduces.Consequently, even merge solution strengthening amount and precipitation strength amount, under the situation that is ferritic single phase structure steel plate, can not obtain the above intensity (reference: table 8, the test number 45 of the table 6 of embodiment, test number 1 to 5 and embodiment) of 780MPa.
According to above reason, the technology of patent documentation 5, can not make have as the object of the invention, tissue is essentially that ferritic is single-phase, tensile strength is more than the 780MPa and the steel plate that also has other characteristic.
Though disclose tensile strength σ B in the patent documentation 6 is the above steel plate (for example, the steel mark A-4 in the embodiment table 2, A-8, A-10, C, E, H) of 780MPa since the YR of these steel plates (% of unit, YR is meant σ here
Y/ σ
B* 100) lower, be 69%～74%, infer that therefore these steel plates contain second phase that martensite equates hard.
Can think that thus the design philosophy of the steel plate that the 780MPa of patent documentation 6 is above is identical with patent documentation 5, mainly be the solution strengthening that effectively utilized Si or Mn and second mutually the phase-change organization's reinforcement that has utilized hard.Therefore, the same with patent documentation 5, need than think after under the manufacturing the stated finishing temperature that preferred temperature range is low when of the present invention (Ae3 point+100 ℃ below), carry out total rolling rate and be rolling more than 25%.For example, according to the embodiment of patent documentation 6, tensile strength σ
BFor the finishing temperature of the steel plate more than the 780MPa is 800 ℃～890 ℃.The steel plate of patent documentation 6 and method of manufacture; Same with patent documentation 5; The growing amount that takes place strain inducing to separate out and be of a size of the precipitate 20nm more than increases, consequently can not make have as the object of the invention, organize that to be essentially the single-phase and tensile strength of ferritic be more than the 780MPa and the steel plate of other characteristic.
The present invention In view of the foregoing, purpose is, the high tensile steel plate of excellent corrosion resistance after stretch flange formability characteristic good and the application after the processing is provided.
The inventor for stretch flange formability characteristic after obtaining processing and application after excellent corrosion resistance, tensile strength be that high tensile hot rolled steel sheet more than the 780MPa is studied, obtain following opinion:
I) in order to obtain the steel plate of excellent corrosion resistance after HS and the application, need make precipitate micro (size is less than 20nm), and improve the ratio of small precipitate (size is less than 20nm).And, keep small state in order to make precipitate, as precipitate, can enumerate material that contains Ti-Mo or the material that contains Ti-V, but from improving the viewpoint of erosion resistance after the application, compound the separating out of Ti and V is useful,
Ii) in order to improve the stretch flangeability after the processing, the solid solution of V is important, and at the solid solution capacity that has only V aspect the characteristic raising.
The present invention is based on above opinion and accomplish, its purport is following.
[1] a kind of high tensile steel plate is characterized in that, has following one-tenth and is grouped into and organizes:
Said composition consists of; In quality %; Contain more than the C:0.02% and below 0.20%, below the Si:0.3%, more than the Mn:0.5% and below 2.5%, below the P:0.06%, below the S:0.01%, below the Al:0.1%, more than the Ti:0.05% and below 0.25%, more than the V:0.05% and below 0.25%; Surplus is made up of Fe and unavoidable impurities
Said tissue is essentially the ferritic single phase structure; In the said ferritic single phase structure, size less than the Ti that precipitate contained of 20nm be more than the 200 quality ppm and below the 1750 quality ppm, V be more than the 150 quality ppm and below the 1750 quality ppm, solid solution V is more than the 200 quality ppm and less than 1750 quality ppm.
[2] like above-mentioned [1] described high tensile steel plate; It is characterized in that; In quality %, also contain and be selected from above and any more than a kind or 2 kinds below 0.5%, more than the W:0.005% and below 0.2%, more than the Zr:0.0005% and in below 0.05% of Cr:0.01%.
Like above-mentioned [1] or [2] described high tensile steel plate, it is characterized in that [3] tensile strength TS is more than the 780MPa.
Like above-mentioned [1] or [2] described high tensile steel plate, it is characterized in that [4] it is below the 3.0mm that the one-sided maximum behind the belt stripping test in the warm saline dip test is peeled off width.
Like above-mentioned [3] described high tensile steel plate, it is characterized in that [5] it is below the 3.0mm that the one-sided maximum behind the belt stripping test in the warm saline dip test is peeled off width.
[6] like above-mentioned [1] or [2] described high tensile steel plate, it is characterized in that the stretch flange formability characteristic λ behind rolling under 10% unit elongation
10Be more than 60%.
[7] like above-mentioned [3] described high tensile steel plate, it is characterized in that the stretch flange formability characteristic λ behind rolling under 10% unit elongation
10Be more than 60%.
In addition, in this manual, %, the ppm of the composition of expression steel are quality %, quality ppm.And high tensile steel plate of the present invention is meant that tensile strength (below, be sometimes referred to as TS) is the above steel plate of 780MPa, and also having implemented surface-treated surface treated steel plate such as for example coating processing with hot-rolled steel sheet and to these steel plates is object.
And, as the characteristic of target of the present invention, the stretch flange formability characteristic (λ under 10% unit elongation after rolling
10) be more than 60%, after one-sided maximum behind the belt stripping test in the warm saline dip test (SDT) stated to peel off width be below the 3.0mm.
The invention effect
According to the present invention, excellent corrosion resistance, TS are the above high tensile hot rolled steel sheet of 780MPa after stretch flange formability characteristic after can obtaining processing and the application.And, in the present invention, can not obtain above-mentioned effect owing to do not add Mo yet, can realize that therefore cost reduces.
And the expectation for example chassis through high tensile hot rolled steel sheet of the present invention being used for automobile, truck can realize the thickness of slab attenuate with vehicle frame etc., reduces the carrying capacity of environment of automobile, significantly improves impact characteristics.
Embodiment
Below, the present invention is at length explained.
(1) at first, the qualification reason to the chemical ingredients (one-tenth is grouped into) of steel of the present invention describes.
More than the C:0.02% and below 0.20%
C becomes carbide and in ferritic, separates out with Ti, V-arrangement, thereby is the element that plays a role aspect the intensity of steel plate.In order to make TS is more than the 780MPa, and need make the C amount is more than 0.02%.On the other hand, if C measures greater than 0.20%, then owing to thickization of precipitate, the formation of second phase constitution, therefore the stretch flange formability characteristic after the processing reduces.According to more than, making C amount is more than 0.02% and below 0.20%, preferably is more than 0.03% and below 0.15%.
Below the Si:0.3%
Though Si is the element that helps solution strengthening, surpass 0.3% if add, then generate cementite at crystal boundary, the stretch flange formability characteristic after the processing reduces.Therefore, making the Si amount is below 0.3%.Preferably be more than 0.001% and below 0.2%.
More than the Mn:0.5% and below 2.5%
Mn is the element that helps solution strengthening.But, if its amount less than 0.5%, then can not obtain the above TS of 780MPa.On the other hand, surpass 2.5%, weldableness is significantly reduced if the Mn amount is added.According to more than, Mn amount is more than 0.5% and below 2.5%, is preferably more than 0.6% and below 2.0%.
Below the P:0.06%
Because P in the original austenite crystal prevention segregation, therefore causes low-temperature flexibility variation and processibility to reduce.Therefore, preferably reduce the P amount as far as possible, be below 0.06%.Preferably be more than 0.001% and below 0.055%.
Below the S:0.01%
If S separates out in the original austenite crystal prevention segregation or with the form of MnS in a large number, low-temperature flexibility is reduced.And, whether process stretch flangeability significantly reduced.Therefore, preferably reduce the S amount as far as possible, be below 0.01%.Preferably be more than 0.0001%, below 0.005%.
Below the Al:0.1%
Al is an effective elements aspect the cleanliness factor raising that makes steel as the reductor of steel and add.In order to obtain this effect, preferably contain the Al more than 0.001%.But,, become the reason of steel plate flaw if produce in a large number greater than 0.1% inclusion.Therefore, making the Al amount is below 0.1%.Be preferably more than 0.01% and below 0.04%.
More than the Ti:0.05% and below 0.25%
Ti makes very important element aspect the ferritic precipitation strength, is obtaining becoming important factor aspect the effect of the present invention.If the Ti amount then is difficult to guarantee necessary strength less than 0.05%.If another fermentation saturated greater than 0.25% this effect, only can increase cost.Therefore, Ti amount is more than 0.05% and below 0.25%, preferably is more than 0.08% and below 0.20%.
More than the V:0.05% and below 0.25%
V is the element that helps to improve intensity with the form of precipitation strength or solution strengthening, and is same with above-mentioned Ti, obtaining becoming important factor aspect the effect of the present invention.Through with an amount of V with the compound interpolation of Ti, have the tendency of separating out less than the form of the small Ti-V carbide of 20nm with particle diameter (following be also referred to as sometimes " size "), and erosion resistance reduces after can as Mo, not making application.If the V amount is less than 0.05%, then above-mentioned additive effect is not enough.On the other hand, if V measures greater than 0.25%, then this effect is saturated, only can increase cost.Therefore, V amount is more than 0.05% and below 0.25%, preferably is more than 0.06% and below 0.20%.
Though must add element through above; Can obtain the target property of steel of the present invention; But must add the element except above-mentioned, can also further add more than the Cr:0.01% and any more than a kind or 2 kinds below 0.5%, more than the W:0.005% and below 0.2%, more than the Zr:0.0005% and in below 0.05% according to following reason.
More than the Cr:0.01% and below 0.5%, more than the W:0.005% and below 0.2%, more than the Zr:0.0005% and below 0.05%
Cr, W and Zr are the same with V, through forming the effect that precipitate or solid solution condition have reinforced ferrite.If Cr amount less than 0.01%, the W amount less than 0.005% or the Zr amount less than 0.0005%, then can help high strength hardly.On the other hand, if Cr amount greater than 0.5%, the W amount greater than 0.2% or the Zr amount greater than 0.05%, processibility variation then.Therefore, any in adding Cr, W, Zr be more than a kind or 2 kinds the time, and making its addition is that Cr:0.01% is above and below 0.5%, more than the W:0.005% and below 0.2%, more than the Zr:0.0005% and below 0.05%.Preferably more than the Cr:0.03% and below 0.3%, more than the W:0.01% and below 0.18%, more than the Zr:0.001% and below 0.04%.
In addition, above-mentioned surplus in addition is made up of Fe and unavoidable impurities.As unavoidable impurities, for example,, therefore preferably it is reduced to below 0.003% because O forms non-metallic inclusion and brings detrimentally affect to quality.And in the present invention, the trace element as hindering action effect of the present invention can contain Cu, Ni, Sn, Sb in the scope below 0.1%.
(2) below, the tissue of high tensile steel plate of the present invention is described.
Be essentially the ferritic single phase structure
TS is more than the 780MPa, and for the stretch flange formability characteristic after improving processing, the ferritic that dislocation desity is low is effectively, and it is effective making and being organized as single phase structure.Particularly, be organized as the ferritic single phase structure that is rich in ductility through making, the raising effect of the stretch flangeability after the processing becomes remarkable.But, be the ferritic single phase structure fully not necessarily also, just can obtain above-mentioned effect fully as long as be essentially the ferritic single phase structure.Here, be essentially the ferritic single phase structure and be meant, except that carbide of the present invention, allow other phase or precipitate of trace, preferred ferritic volume fraction is more than 95%.And,,, can not influence characteristic of the present invention even then contain the tissue of cementite, perlite, bainite if volume fraction is the scope below 5% yet.
In addition; Ferritic volume fraction is obtained through following method: the nital with 3% shows the microstructure in the thickness of slab cross section parallel with rolling direction; Use sem (SEM) under 1500 multiplying powers, to observe the position of thickness of slab 1/4, use for example image processing software " particle analysis II " the mensuration ferritic area occupation ratio of the テ of Sumitomo Metal Industries Network ノ ロ ジ one Co., Ltd.'s system.
In the ferritic single phase structure, size less than the Ti that precipitate contained of 20nm be more than the 200ppm and below the 1750ppm, V is more than the 150ppm and below 1750ppm
In high tensile steel plate of the present invention, the precipitate that contains Ti and/or V is mainly separated out in ferritic with the form of carbide.Think that this is because the cause that little, the oversaturated C of solid solubility limit of the C in the ferritic separates out with the form of carbide easily in ferritic.And, since above-mentioned precipitate, soft ferritic hardization (high firmnessization), and becoming to obtain the above TS of 780MPa.And YS raises, can obtain more than 83% YR (=YS/YR).
In order to obtain high tensile steel plate, the ratio that makes precipitate micro (size is less than 20nm) as described above and improve this small precipitate (size is less than 20nm) is important.If precipitate is of a size of more than the 20nm, the effect that then suppresses dislocation moving is little, can not make the ferritic hardization fully, the situation that therefore exists intensity to reduce.
And the result of research shows that about erosion resistance after the application, the precipitate size is small to be important.In existing Ti system (adding Ti separately) HSLA steel, the increase along with the addition of Ti exists precipitate to be prone to the tendency of thickization.Therefore, there is the tendency that also reduces along with erosion resistance after intensity reduction, the application in such steel plate.Though the reason that erosion resistance reduces along with thickization of precipitate after the application is also unclear, think that thick precipitate hinders the cause that the chemical conversion crystalline generates or grows.
According to more than, the size of preferred precipitate is less than 20nm.Should be less than the small precipitate of 20nm through adding Ti simultaneously and V realizes.Main and the Ti formation double carbide of V.Though reason is also unclear, can know that the high temperature of these precipitates in the coiling temperature of the scope of the invention down, stably exists with small state for a long time.
And size becomes important less than the Ti that precipitate the contained amount of 20nm and the control of V amount.If the Ti that precipitate the contained amount less than 20nm is measured less than 150ppm less than 200ppm and V, then the number density of precipitate diminishes, and the interval of each precipitate enlarges, and the effect that therefore suppresses dislocation moving diminishes.Therefore, owing to can not make ferritic hardization fully, therefore can not get TS is the above intensity of 780MPa.And for during less than 150ppm, existing precipitate to be prone to the tendency of thickization more than the 200ppm and less than the V that precipitate the contained amount of 20nm, therefore can not get TS sometimes is the above intensity of 780MPa less than the Ti that precipitate contained of 20nm amount.In addition, less than being 150ppm when above more than the 200ppm and less than the V that precipitate the contained amount of 20nm, therefore the precipitation efficiency variation of V exists the situation that TS is the above intensity of 780MPa that can not get less than the Ti that precipitate contained of 20nm amount.On the other hand, if separate out greater than 1750ppm greater than 1750ppm or V amount less than the Ti that precipitate the contained amount of 20nm, then erosion resistance reduces after the application, can not obtain target property.This thinks that the chemical conversion crystalline generates or the cause of growth because a large amount of small precipitates hinders at surface of steel plate.Therefore, need satisfy simultaneously size less than 20nm precipitate contained separates out the Ti amount and separate out the V amount.
And can know that size is less than the Ti that precipitate the contained amount of 20nm and the ratio of V amount, can access the above TS of 785MPa, reaches preferred state at 0.4≤(Ti/48)/(V/51)≤2.5 o'clock.Though reason and unclear is thought because through with the ratio of components optimization of Ti and V and the cause of thermostability raising.
According to more than, make size less than the Ti that precipitate contained of 20nm amount for more than the 200ppm and below the 1750ppm, the V amount is for more than the 150ppm and below 1750ppm.And preferred size is 0.4≤(Ti/48)/(V/51)≤2.5 less than the Ti that precipitate the contained amount of 20nm and the ratio of V amount.
In addition, sometimes precipitate and/or inclusion are referred to as precipitate etc.
In addition, can control above-mentioned Ti amount and V amount through coiling temperature.The coiling temperature of this moment is preferably more than 500 ℃ and below 700 ℃.If coiling temperature is higher than 700 ℃ of thickization that then cause precipitate, be respectively less than 200ppm, less than 150ppm less than the Ti that precipitate contained of 20nm and the amount of separating out of V, can not obtain the above TS of 780MPa.And, when coiling temperature is lower than 500 ℃, also be respectively less than 200ppm, less than 150ppm less than the Ti that precipitate contained of 20nm and the amount of separating out of V.This thinks because the low thereby inadequate cause of diffusion Ti and V of coiling temperature.
Size can be confirmed through following method less than the Ti that precipitate contained amount and the V amount of 20nm.
In electrolytic solution behind the sample of electrolysis predetermined amount, from electrolytic solution, take out coupons and be immersed in and have in the dispersed solution.Then, use the strainer of aperture 20nm to filter the precipitate that is contained in this solution.The size of the precipitate of the strainer that passes through this aperture 20nm with filtrating is less than 20nm.Then; From inductively coupled plasma (ICP) emission spectrometry method, ICP mass analysis and atomic absorption spectrometry etc., suitably select a kind of method; Filtrate filtered is analyzed, obtained Ti that precipitate contained amount and the V amount of size less than 20nm.
Solid solution V amount is above and less than the tissue of 1750ppm for 200ppm
In the present invention, solid solution V amount is most important factor.In order to improve the stretch flange formability characteristic after the processing, the solid solution of V is important.Then its effect is not enough if solid solution V is less than 20ppm, in order to obtain above-mentioned effect, need make solid solution V amount for more than the 200ppm.On the other hand, for more than the 1750ppm, then this effect is saturated as if solid solution V amount, therefore should be worth it as higher limit.
According to more than, make solid solution V amount above and less than 1750ppm for 200ppm.In addition; Though the processibility of steel of the present invention is along with the rising of intensity also has reduction slightly; But if size less than the Ti that precipitate contained of 20nm amount for below the 1750ppm, the V amount is in the scope below the 1750ppm; Then, can fully guarantee as the stretch flange formability characteristic after the processing of target through making solid solution V amount for more than the 200ppm.
In addition,, for example can confirm for more than the 200ppm and about solid solution V amount through following method less than 1750ppm.
In non-aqueous solvent class electrolytic solution, only behind the sample of electrolysis predetermined amount, electrolytic solution is carried out ultimate analysis as analytical solution.As analytical procedure, can enumerate inductively coupled plasma (ICP) emission spectrometry method, ICP mass analysis or atomic absorption spectrometry etc.
(3) below, the method for manufacture of high tensile steel plate of the present invention is described.
High tensile steel plate of the present invention for example obtains as follows: the steel billet that will be adjusted to above-mentioned chemical ingredients scope is heated to more than 1150 ℃ and after below 1350 ℃; Be made as more than 850 ℃ finishing temperature and below 1100 ℃ and carry out hot rolling; Then, batch under 700 ℃ at 500 ℃.At length explain in the face of these optimum conditions down.
Billet heating temperature: more than 1150 ℃ and below 1350 ℃
Carbide forming element such as Ti or V almost all exists with the form of precipitate in steel billet.For it is being separated out in ferritic structure according to target after hot rolling, need before hot rolling, temporarily dissolve the precipitate of separating out with the form of carbide.Therefore need heat more than 1150 ℃.
If be lower than 1150 ℃; Then because the carbide more than the size 20nm that erosion resistance after precipitation strength and the application is not had to help is residual; Therefore reduce less than the generation of the small precipitate of 20nm relevant Ti amount and V amount with the size that needs in order to obtain effect of the present invention; After state batch the time, can not obtain the amount of size according to target less than the precipitate of 20nm.And in the method for manufacture of steel plate of the present invention, most preferred mode is: when steel billet heats and during finish to gauge, making the carbide that contains Ti, V is the dissolved state, and the form with the small carbide that contains Ti, V is separated out during batching after finish to gauge.Therefore, as this carbide dissolved temperature almost completely, Heating temperature is more preferably more than 1170 ℃.
On the other hand, if be heated above 1350 ℃, then the crystallization particle diameter becomes too thick, and the stretch flange formability characteristic after the processing, tensile properties be variation all.And, if as long as the heat-treat condition that relates to after considering then below 1300 ℃, just almost can prevent thickization of crystallization particle diameter fully.
Therefore, billet heating temperature is preferably more than 1150 ℃ and below 1350 ℃.More preferably more than 1170 ℃ and below 1300 ℃.
Hot rolled finishing temperature: more than 850 ℃ and below 1100 ℃
In order to obtain Ti that precipitate contained amount and the V amount of size of the present invention less than 20nm, the control of finishing temperature becomes important.Preferably under as 850 ℃～1100 ℃ of the finishing temperatures of hot rolled end temp, the steel billet after the processing is carried out hot rolling.If finishing temperature is lower than 850 ℃, then be rolled in ferritic+austenitic zone, become the unfolded ferritic structure, therefore there are the stretch flange formability characteristic after processing, the situation of tensile properties variation.And, even temporarily dissolved the precipitate of before making billet heating temperature be carry out more than 1150 ℃ rolling, separating out, be lower than in finishing temperature under 850 ℃ the situation with the carbide form, because strain inducing is separated out, the carbide that contains Ti, V is also separated out.Therefore, and reach the needed size of effect of the present invention less than the relevant Ti of the generation of the small precipitate of 20nm amount and the minimizing of V amount, after state batch the time can not according to target obtain the amount of size less than the precipitate of 20nm.That is, the temporary transient lysed carbide that contains Ti, V when above-mentioned steel billet heating also is in the dissolved state as far as possible in this finish to gauge, and this is important as far as getting into following coiling process.Therefore, be the dissolved state in order to keep carbide, more preferably making finishing temperature is more than 935 ℃.
On the other hand, if finishing temperature is higher than 1100 ℃,, therefore there is the situation of the TS that can not obtain 780MPa then owing to thickization of ferrite crystal grain.In order to prevent thickization of ferrite crystal grain, more preferably making finishing temperature is below 990 ℃.
Therefore, finishing temperature is preferably more than 850 ℃ and below 1100 ℃.More preferably more than 935 ℃ and below 990 ℃.
Coiling temperature: more than 500 ℃ and below 700 ℃
In order to obtain Ti that precipitate contained amount and the V amount of size of the present invention less than 20nm, the control of coiling temperature becomes important.This be because, as previously mentioned, most preferred manufacture is: in this coiling process, form a large amount of nucleation sites, carbide is separated out by this nucleation site, and, suppress the grain growing of this carbide, its size is not reached more than the 20nm.Obtain characteristic of the present invention in order to make tissue be essentially the ferritic single phase structure, coiling temperature is preferably more than 500 ℃ and below 700 ℃.
In the present invention, if coiling temperature is lower than 500 ℃, the quantitative change of separating out that then contains the carbide of Ti and/or V gets insufficiently, has the situation that causes intensity to reduce.And, generating the bainite phase, existence can not obtain the situation of ferritic single phase structure.
In order to be formed into epipole in a large number and carbide to be generated by this nucleation site, preferably make temperature higher, become preferred condition more than 550 ℃.
On the other hand,, then cause thickization of the carbide of separating out, have the situation that causes intensity to reduce if coiling temperature is higher than 700 ℃.And pearlitic transformation gets easily and generates, the situation that exists the stretch flangeability after causing processing to reduce.Making coiling temperature is below 650 ℃ the time, thickization of the carbide that has prevented really to separate out, therefore more preferably.
Therefore, preferred coiling temperature is more than 500 ℃ and below 700 ℃, more preferably more than 550 ℃ and below 650 ℃.
Steel plate of the present invention comprises has implemented the steel plate that surface treatment, surface coating are handled to the surface.Particularly, can on steel plate of the present invention, form pot galvanize is plated film and be that steel plate is used preferably as pot galvanize.That is, be that plated film also can be kept good processibility, even therefore form pot galvanize because steel plate of the present invention has good processibility.Here, pot galvanize is that coating is meant that it is the main body hot-dip coating of (promptly contain and have an appointment more than 90%) that zinc reaches with zinc, can also contain alloying elements such as Al, Cr beyond dezincifying, and, even having implemented pot galvanize is plating, also can behind plating, carry out Alloying Treatment.
In addition, the melting method of steel does not have special qualification, and generally well-known melting method all can use.For example,, preferably carry out melting, carry out the purified method 2 times through the vacuum stripping stove through converter, electric furnace etc. as melting method.From the viewpoint of productivity, quality aspect, the preferred continuous metal cast process of castmethod.And hot rolled is directly rolling, or to have carried out implementing carrying out under the state after being the heating of purpose with the insulation hot rolled directly rolling even carry out carrying out immediately after the casting, to effect of the present invention also not influence.And, after roughing, before the finish to gauge, hot-finished material is heated, perhaps, after roughing, rolling stock is engaged and carry out continuously hot rolling, perhaps, carry out the heating and the continuous rolling of hot-finished material simultaneously, effect of the present invention all can not suffer damage.
Embodiment
Embodiment 1
With the steel of forming shown in the converter melting table 1, process steel billet through continuous casting.Then, under condition shown in the table 2, these steel billets are implemented heating, hot rolling, batched, process the hot-rolled steel sheet of thickness of slab 2.0mm.
Table 1
For the hot-rolled steel sheet of gained,, obtain less than the Ti that precipitate the contained amount of 20nm and the amount of V amount and solid solution V through the methods analyst microstructure shown in following.And, obtain tensile strength through the method shown in following: the stretch flange formability characteristic after TS, the processing: λ
10And the one-sided maximum of erosion resistance: SDT is peeled off width after the application, and estimate.
The analysis of microstructure
To be cut into suitable size through the above-mentioned hot-rolled steel sheet that obtains, in 10%AA electrolytic solution (10 volume % methyl ethyl diketone-1 quality % tetramethyl ammonium chloride-methyl alcohol), will about 0.2g with 20mA/cm
2Current density carry out constant-current electrolysis.
Size is less than the Ti that precipitate the contained amount of 20nm and the mensuration of V amount
With the surface attachment after the electrolysis coupons of precipitate from electrolytic solution, take out; Be immersed in the sodium hexametaphosphate solution (500ml/l) (below be called the SHMP aqueous solution); Apply ultrasonic vibration, precipitate is peeled off from coupons, be extracted in the SHMP aqueous solution.Then, contain the SHMP aqueous solution of precipitate, and use ICP emmission spectrometric analysis device that filtrate filtered is analyzed, Ti in the mensuration filtrating and the absolute magnitude of V with the strainer filtration of aperture 20nm.Then, divided by electrolysis weight, obtain Ti that precipitate contained amount and the V amount of size with the absolute magnitude of Ti and V less than 20nm.In addition, electrolyte weight is to obtain through the weight of the sample after measuring precipitate and peeling off and with deducting its sample weight before electrolysis.
The mensuration of the amount of solid solution V
As analytical solution, use the ICP mass analysis to measure V and the concentration of reference element Fe in solution with the electrolytic solution after the electrolysis.Based on resulting concentration, calculate the concentration ratio of V, and multiply by the containing ratio of Fe in the sample with respect to Fe, obtain the amount of the V of solid solution condition thus.The total amount of the value that in addition, the containing ratio of the Fe in the sample can be through deducting the composition except that Fe from 100% is obtained.
TS
Rolling direction is made as draw direction, uses the JIS5 test film, carry out tension test, obtain TS through method based on JIS Z2241.
Stretch flange formability characteristic after the processing: λ
10
With 10% unit elongation rolling after, carry out drifiting test based on the Japanese iron and steel standard JFST of federation 1001, obtain λ
10
The one-sided maximum of erosion resistance after the application: SDT is peeled off width
Use the grease-removing agent of Japanese ペ イ Application ト Co., Ltd. system: サ one Off Network リ one Na one ECO90, surface conditioner: サ one Off Off ア イ Application 5N-10, chemical conversion treating agent: サ one Off ダ イ Application SD2800, implement chemical conversion in each temperature and concentration conditions under than standard conditions harsh conditions and handle.1 example as standard conditions; Degreasing process is: concentration 16g/l, 42～44 ℃ of treatment temps, treatment time 120s, spray degreasing, surface adjustment operation is: total alkalinity 1.5～2.5 points, free acidity 0.7～0.9 point, promoter concentration 2.8～3.5 points, 44 ℃ of treatment temps, treatment time 120s.As mal-condition, make the treatment temp of chemical conversion treatment process be reduced to 38 ℃.Then, use the electrodeposition coating agent of Japanese ペ イ Application ト corporate system: V-50 carries out electrophoretic painting.The adhesion amount that overlay film is handled in chemical conversion is 2～2.5g/m
2, electrophoretic painting is a target with thickness 25 μ m.
The evaluation of erosion resistance is carried out through warm saline dip test (SDT) after the application.Give the sample cruciform flaw of having implemented chemical conversion processing, electrophoretic painting with cutting machine; Dipping is after 10 days in warm saline (5%NaCl:55 ℃); Washing, drying, portion carries out tape stripping to the cutting flaw, and the maximum of measuring about cutting flaw portion is peeled off width.If to peel off width be below the 3.0mm to one-sided maximum, then we can say application after erosion resistance good.
To be shown in table 2 with creating conditions through the result that above method obtains.
Can know that according to table 2 TS of the present invention's example is that 780MPa is above, λ
10Be more than 60%, the one-sided maximum of SDT peels off width and reaches below the 3.0mm, is the hot-rolled steel sheet of excellent corrosion resistance after stretch flange formability characteristic and the application after the processing.
On the other hand, the TS of comparative example (intensity), λ
10(the stretch flange formability characteristic after the processing), the one-sided maximum of SDT are peeled off any poor more than 1 in the width (erosion resistance after the application).
Embodiment 2
With the steel of forming shown in the converter melting table 3, process steel billet through continuous casting.Then, under condition shown in the table 4, these steel billets are implemented heating, hot rolling, batched, process the hot-rolled steel sheet of thickness of slab 2.0mm.
Table 3
For the hot-rolled steel sheet of gained,, obtain less than the Ti that precipitate the contained amount of 20nm and the amount of V amount and solid solution V through the methods analyst microstructure identical with embodiment 1.And, through obtaining tensile strength: the stretch flange formability characteristic after TS, the processing: λ with embodiment 1 identical method
10And the one-sided maximum of erosion resistance: SDT is peeled off width after the application, and estimate.
The above result who obtains is shown in table 4.
Can know that according to table 4 TS of the present invention's example is that 780MPa is above, λ
10Be more than 60%, the one-sided maximum of SDT peels off width and reaches below the 3.0mm, is the hot-rolled steel sheet of excellent corrosion resistance after stretch flange formability characteristic and the application after the processing.
And, compare with steel plate No.1 (table 2), added steel plate No25～28,35～37 of Cr, W or Zr, TS further improves.
Utilize possibility on the industry
Steel plate of the present invention is a HS, and has erosion resistance after stretch flange formability characteristic and the application after the good processing, therefore, is suitable as for example automobile, truck need unit elongation and stretch flange formability characteristic with vehicle frame etc. parts most.
Claims (7)
1. a high tensile steel plate is characterized in that, has following one-tenth and is grouped into and organizes:
Said composition consists of; In quality %; Contain more than the C:0.02% and below 0.20%, below the Si:0.3%, more than the Mn:0.5% and below 2.5%, below the P:0.06%, below the S:0.01%, below the Al:0.1%, more than the Ti:0.05% and below 0.25%, more than the V:0.05% and below 0.25%; Surplus is made up of Fe and unavoidable impurities
Said tissue is essentially the ferritic single phase structure; Wherein ferritic volume fraction is more than 95%; In said ferritic single phase structure; Solid solution V is that 200 quality ppm are above and less than 1750 quality ppm, size less than the Ti that precipitate contained of 20nm be more than the 200 quality ppm and below the 1750 quality ppm, V is more than the 150 quality ppm and below 1750 quality ppm.
2. high tensile steel plate as claimed in claim 1; It is characterized in that; In quality %, also contain and be selected from above and any more than a kind or 2 kinds below 0.5%, more than the W:0.005% and below 0.2%, more than the Zr:0.0005% and in below 0.05% of Cr:0.01%.
3. according to claim 1 or claim 2 high tensile steel plate is characterized in that tensile strength TS is more than the 780MPa.
4. according to claim 1 or claim 2 high tensile steel plate is characterized in that it is below the 3.0mm that the one-sided maximum behind the belt stripping test in the warm saline dip test is peeled off width.
5. high tensile steel plate as claimed in claim 3 is characterized in that, it is below the 3.0mm that the one-sided maximum behind the belt stripping test in the warm saline dip test is peeled off width.
6. according to claim 1 or claim 2 high tensile steel plate is characterized in that, the stretch flange formability characteristic λ behind rolling under 10% unit elongation
10Be more than 60%.
7. high tensile steel plate as claimed in claim 3 is characterized in that, the stretch flange formability characteristic λ behind rolling under 10% unit elongation
10Be more than 60%.
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| PCT/JP2008/064175 WO2009017256A1 (en) | 2007-07-31 | 2008-07-31 | High-strength steel sheet |
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| EP (1) | EP2177640B1 (en) |
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| JP2007070647A (en) * | 2005-09-02 | 2007-03-22 | Nippon Steel Corp | High strength steel sheet, and method for producing the same |
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| JPS591502B2 (en) | 1980-07-01 | 1984-01-12 | 三島光産株式会社 | thermal slab cutting equipment |
| CN1153841C (en) * | 2000-10-31 | 2004-06-16 | 杰富意钢铁株式会社 | High tensile hot rolled steel sheet and method for production thereof |
| JP3879440B2 (en) * | 2001-06-07 | 2007-02-14 | Ｊｆｅスチール株式会社 | Manufacturing method of high strength cold-rolled steel sheet |
| JP4028719B2 (en) | 2001-11-26 | 2007-12-26 | 新日本製鐵株式会社 | Squeezable burring high-strength thin steel sheet having excellent shape freezing property and manufacturing method thereof |
| KR100949694B1 (en) * | 2002-03-29 | 2010-03-29 | 제이에프이 스틸 가부시키가이샤 | Cold rolled steel sheet having ultrafine grain structure and method for producing the same |
| JP3821036B2 (en) | 2002-04-01 | 2006-09-13 | 住友金属工業株式会社 | Hot rolled steel sheet, hot rolled steel sheet and cold rolled steel sheet |
| JP4007051B2 (en) | 2002-04-30 | 2007-11-14 | Ｊｆｅスチール株式会社 | High strength thin steel plate with excellent thermal stability |
| JP4304421B2 (en) | 2002-10-23 | 2009-07-29 | 住友金属工業株式会社 | Hot rolled steel sheet |
| JP4214840B2 (en) * | 2003-06-06 | 2009-01-28 | 住友金属工業株式会社 | High-strength steel sheet and manufacturing method thereof |
| JP4232545B2 (en) * | 2003-06-11 | 2009-03-04 | 住友金属工業株式会社 | High-strength hot-rolled steel sheet and its manufacturing method |
| JP4581665B2 (en) | 2004-12-08 | 2010-11-17 | 住友金属工業株式会社 | High-strength hot-rolled steel sheet and its manufacturing method |
| JP4452191B2 (en) * | 2005-02-02 | 2010-04-21 | 新日本製鐵株式会社 | Manufacturing method of high-stretch flange-formable hot-rolled steel sheet with excellent material uniformity |
| US7955444B2 (en) * | 2005-08-05 | 2011-06-07 | Jfe Steel Corporation | High strength steel sheet and method for manufacturing the same |
| JP4736853B2 (en) * | 2006-02-28 | 2011-07-27 | Ｊｆｅスチール株式会社 | Precipitation strengthened high strength steel sheet and method for producing the same |
| JP4528275B2 (en) * | 2006-03-20 | 2010-08-18 | 新日本製鐵株式会社 | High-strength hot-rolled steel sheet with excellent stretch flangeability |
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2008
- 2008-07-29 JP JP2008194546A patent/JP5326403B2/en not_active Expired - Fee Related
- 2008-07-31 CN CN2008801012051A patent/CN101772584B/en active Active
- 2008-07-31 KR KR1020107001975A patent/KR20100029138A/en active Search and Examination
- 2008-07-31 MX MX2010001110A patent/MX2010001110A/en active IP Right Grant
- 2008-07-31 EP EP08792282.9A patent/EP2177640B1/en active Active
- 2008-07-31 TW TW097128967A patent/TWI390050B/en not_active IP Right Cessation
- 2008-07-31 CA CA2693489A patent/CA2693489C/en not_active Expired - Fee Related
- 2008-07-31 US US12/670,153 patent/US20100196189A1/en not_active Abandoned
- 2008-07-31 WO PCT/JP2008/064175 patent/WO2009017256A1/en active Application Filing
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| CN1139459A (en) * | 1994-11-04 | 1997-01-01 | 新日本制铁株式会社 | High-strength ferritic heat-resistant steel and process for producing the same |
| JP2002161340A (en) * | 2000-11-24 | 2002-06-04 | Nippon Steel Corp | Hot rolled steel sheet superior in burring workability and fatigue characteristics, and manufacturing method therefor |
| CN1462316A (en) * | 2001-05-09 | 2003-12-17 | 住友金属工业株式会社 | Ferritic heat-resistant steel |
| JP2005120430A (en) * | 2003-10-16 | 2005-05-12 | Jfe Steel Kk | Designing method for precipitation-strengthened high-strength steel sheet, manufacturing method therefor, and precipitation-strengthened high-strength steel sheet |
| JP2007070647A (en) * | 2005-09-02 | 2007-03-22 | Nippon Steel Corp | High strength steel sheet, and method for producing the same |
Also Published As
| Publication number | Publication date |
|---|---|
| CN101772584A (en) | 2010-07-07 |
| EP2177640A1 (en) | 2010-04-21 |
| JP5326403B2 (en) | 2013-10-30 |
| CA2693489C (en) | 2013-11-19 |
| JP2009052139A (en) | 2009-03-12 |
| EP2177640B1 (en) | 2017-11-01 |
| WO2009017256A1 (en) | 2009-02-05 |
| KR20100029138A (en) | 2010-03-15 |
| TW200912015A (en) | 2009-03-16 |
| US20100196189A1 (en) | 2010-08-05 |
| EP2177640A4 (en) | 2012-01-18 |
| MX2010001110A (en) | 2010-03-09 |
| CA2693489A1 (en) | 2009-02-05 |
| TWI390050B (en) | 2013-03-21 |
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