CN107849654A - Cold-rolled steel sheet and its manufacture method - Google Patents
Cold-rolled steel sheet and its manufacture method Download PDFInfo
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- CN107849654A CN107849654A CN201680034903.9A CN201680034903A CN107849654A CN 107849654 A CN107849654 A CN 107849654A CN 201680034903 A CN201680034903 A CN 201680034903A CN 107849654 A CN107849654 A CN 107849654A
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- 239000010960 cold rolled steel Substances 0.000 title claims abstract description 65
- 238000000034 method Methods 0.000 title claims abstract description 40
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 24
- 239000000203 mixture Substances 0.000 claims abstract description 36
- 229910000859 α-Fe Inorganic materials 0.000 claims abstract description 35
- 239000012535 impurity Substances 0.000 claims abstract description 8
- 229910000831 Steel Inorganic materials 0.000 claims description 69
- 239000010959 steel Substances 0.000 claims description 69
- 238000005096 rolling process Methods 0.000 claims description 42
- 238000001816 cooling Methods 0.000 claims description 36
- 238000000137 annealing Methods 0.000 claims description 27
- 238000010438 heat treatment Methods 0.000 claims description 25
- 238000005098 hot rolling Methods 0.000 claims description 23
- 239000002994 raw material Substances 0.000 claims description 21
- 210000000981 epithelium Anatomy 0.000 claims description 19
- 238000007747 plating Methods 0.000 claims description 18
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 18
- 238000005097 cold rolling Methods 0.000 claims description 14
- 230000009467 reduction Effects 0.000 claims description 14
- 239000002184 metal Substances 0.000 claims description 5
- 229910052751 metal Inorganic materials 0.000 claims description 5
- 210000001519 tissue Anatomy 0.000 claims description 5
- 229910052785 arsenic Inorganic materials 0.000 claims description 4
- 229910052792 caesium Inorganic materials 0.000 claims description 4
- 229910052804 chromium Inorganic materials 0.000 claims description 4
- 229910052802 copper Inorganic materials 0.000 claims description 4
- 229910052735 hafnium Inorganic materials 0.000 claims description 4
- 229910052745 lead Inorganic materials 0.000 claims description 4
- 229910052749 magnesium Inorganic materials 0.000 claims description 4
- 229910052758 niobium Inorganic materials 0.000 claims description 4
- 229910052718 tin Inorganic materials 0.000 claims description 4
- 229910052719 titanium Inorganic materials 0.000 claims description 4
- 229910052721 tungsten Inorganic materials 0.000 claims description 4
- 229910052720 vanadium Inorganic materials 0.000 claims description 4
- 229910052726 zirconium Inorganic materials 0.000 claims description 4
- 229910052787 antimony Inorganic materials 0.000 claims 1
- 229910052750 molybdenum Inorganic materials 0.000 claims 1
- 229910052782 aluminium Inorganic materials 0.000 abstract description 4
- 229910052748 manganese Inorganic materials 0.000 abstract description 4
- 229910052796 boron Inorganic materials 0.000 abstract description 3
- 229910052757 nitrogen Inorganic materials 0.000 abstract description 3
- 229910052698 phosphorus Inorganic materials 0.000 abstract description 2
- 229910052710 silicon Inorganic materials 0.000 abstract description 2
- 229910052717 sulfur Inorganic materials 0.000 abstract description 2
- 238000005452 bending Methods 0.000 description 17
- 238000012360 testing method Methods 0.000 description 17
- 239000013078 crystal Substances 0.000 description 16
- 229910001567 cementite Inorganic materials 0.000 description 12
- KSOKAHYVTMZFBJ-UHFFFAOYSA-N iron;methane Chemical compound C.[Fe].[Fe].[Fe] KSOKAHYVTMZFBJ-UHFFFAOYSA-N 0.000 description 12
- 230000000694 effects Effects 0.000 description 10
- 238000001556 precipitation Methods 0.000 description 10
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 8
- 238000003754 machining Methods 0.000 description 8
- 230000008569 process Effects 0.000 description 8
- 229910052799 carbon Inorganic materials 0.000 description 5
- 238000007598 dipping method Methods 0.000 description 5
- 238000005246 galvanizing Methods 0.000 description 5
- 238000005554 pickling Methods 0.000 description 5
- 229910045601 alloy Inorganic materials 0.000 description 4
- 239000000956 alloy Substances 0.000 description 4
- 230000007797 corrosion Effects 0.000 description 4
- 238000005260 corrosion Methods 0.000 description 4
- 238000009826 distribution Methods 0.000 description 4
- 230000006698 induction Effects 0.000 description 4
- 239000002244 precipitate Substances 0.000 description 4
- 238000001953 recrystallisation Methods 0.000 description 4
- 230000000630 rising effect Effects 0.000 description 4
- 239000011701 zinc Substances 0.000 description 4
- 238000002441 X-ray diffraction Methods 0.000 description 3
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 3
- 229910007567 Zn-Ni Inorganic materials 0.000 description 3
- 229910007614 Zn—Ni Inorganic materials 0.000 description 3
- 238000005266 casting Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 239000010813 municipal solid waste Substances 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 238000005498 polishing Methods 0.000 description 3
- 238000007670 refining Methods 0.000 description 3
- 239000006104 solid solution Substances 0.000 description 3
- 229910052725 zinc Inorganic materials 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 230000032683 aging Effects 0.000 description 2
- 238000005336 cracking Methods 0.000 description 2
- 238000005315 distribution function Methods 0.000 description 2
- 238000009713 electroplating Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 150000004767 nitrides Chemical class 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 238000007493 shaping process Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- POAOYUHQDCAZBD-UHFFFAOYSA-N 2-butoxyethanol Chemical compound CCCCOCCO POAOYUHQDCAZBD-UHFFFAOYSA-N 0.000 description 1
- 208000037656 Respiratory Sounds Diseases 0.000 description 1
- 230000018199 S phase Effects 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 229910001566 austenite Inorganic materials 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000004566 building material Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- KFSUNTUMPUWCMW-UHFFFAOYSA-N ethanol;perchloric acid Chemical compound CCO.OCl(=O)(=O)=O KFSUNTUMPUWCMW-UHFFFAOYSA-N 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 230000008707 rearrangement Effects 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000005482 strain hardening Methods 0.000 description 1
- 230000035882 stress Effects 0.000 description 1
- 230000008719 thickening Effects 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0226—Hot rolling
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0236—Cold rolling
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
- C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/004—Dispersions; Precipitations
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Sheet Steel (AREA)
Abstract
It is an object of the present invention to provide the cold-rolled steel sheet with excellent bendability and its manufacture method.There are cold-rolled steel sheet following compositions to form and organize, and the composition composition contains C in terms of quality %：Less than more than 0.010% 0.035%, Si：Less than 0.1%, Mn：Less than 0.35%, P：Less than 0.035%, S：Less than 0.02%, N：Less than 0.010%, Al：Less than more than 0.005 0.03% and B：Less than more than 0.0001% 0.005%, remaining part is made up of Fe and inevitable impurity, the ferrite average grain diameter of the tissue is less than 20 μm, and to meet that the condition of following formula (1) separates out, the n values of range of strain 5~10% are more than 0.15 by BN and AlN.0 ＜ [BN]/[AlN]≤0.5 (1).Here, [BN] and [AlN] is respectively the BN and AlN represented with same units individual number density.
Description
Technical field
The present invention relates to cold-rolled steel sheet, in particular to being suitable as the structural members such as automotive part, house, family
Raw material, excellent in workability the cold-rolled steel sheet of the tectosome of tool, desk, family's electrical article etc..It is moreover, it relates to described cold
The manufacture method of rolled steel plate.
Background technology
For cold-rolled steel sheet, due to its good mouldability, the raw material of diversified tectosome is accordingly acted as.When
When manufacturing the tectosome of complicated shape using cold-rolled steel sheet, generally, pressurizeed using to flat cold-rolled steel sheet so as to process
Method as further being engaged each other into complicated 3D shape, by obtained processed goods.Therefore, for as tectosome
For the cold-rolled steel sheet of raw material, it is desirable to its excellent in workability.
Therefore, based on various viewpoints, the exploitation to the cold-rolled steel sheet of excellent in workability is carried out.For example, in patent document 1
Disclose by continuous annealing and subsequent skin pass rolling, to manufacture the method for the good Non-ageing cold-rolled steel sheet of processability.
In the above method described in patent document 1, C, Mn, Al, N amount of steel are reduced, and by with more than 50% pressure
After rate cold rolling, annealed with defined condition after cooling, Wetted constructures and skin pass rolling, which thereby enhance cold-rolled steel
The ageing resistance of plate.
In addition, Patent Document 2 discloses by that will contain C, Mn, S, O and B with defined amount under the conditions of defined
Steel continuously casting after, carry out hot rolling, cold rolling, continuous annealing, so as to manufacture the method for the cold-rolled steel sheet of excellent in workability.Patent
Disclosed in document 3 by continuous after steel progress hot rolling of the defined amount containing C, Si, Mn, P, Al, N, cold rolling
During annealing, quickly heating, quick cooling are carried out, so as to manufacture the method for the cold-rolled steel sheet of ageing resistance and excellent in workability.Specially
Disclosed in sharp document 4 by the way that the ratio between the Si in steel and Mn amount are set into defined scope, so as to control ferrite grain
Footpath and the precipitation state of cementite, the method for manufacturing the cold-rolled steel sheet of excellent in bending workability.
Prior art literature
Patent document
Patent document 1：Japanese Unexamined Patent Application 61-124533 publications
Patent document 2：Japanese Unexamined Patent Publication 02-267227 publications
Patent document 3：Japanese Unexamined Patent Publication 07-216459 publications
Patent document 4：Japanese Unexamined Patent Publication 2013-209725 publications
The content of the invention
The invention problem to be solved
However, in the method described in patent document 1, although resistance to timeliness can be manufactured by adjusting skin pass rolling condition
The good steel plate of property, but it is adjusted merely by skin pass rolling condition, it is impossible to reach the level of the processability currently required.
In addition, in the method described in patent document 2, due to controlling MnS's by forming oxide system field trash
Size, it is therefore desirable to the oxygen containing more than 60ppm in steel.As a result, the field trash of oxide system largely produces, thus exist with
The problem of above-mentioned field trash cracks for starting point in punch forming.
In the method described in patent document 3, due to carrying out quick heating and quick cooling, accordingly, it is difficult to make hot place
Manage bar part steel plate, especially become uniform in the overall scope in thickness of slab direction.And, as a result, the tissue that steel plate be present becomes
Obtain the problem of bendability uneven, that steel plate can not be made overall improves.
In the method described in patent document 4, due to separating out cementite, therefore, yield strength in ferrite crystal grain
Rise, n values reduce.As a result, because the Strain Distribution in bending machining portion is easy to become uneven, therefore not only cannot be sufficient
Bendability, but also the problem of the deviation that bendability be present is big.
Like this, in the prior art, it is difficult to industrially stably provide bendability good cold-rolled steel sheet.This
Invention is made in view of the above problems, its object is to, there is provided have excellent bendability cold-rolled steel sheet and its
Manufacture method.
For the means to solve the above problems
That is, purport of the invention forms as described below.
1. cold-rolled steel sheet, there are following compositions to form and organize for it,
The composition composition is contained in terms of quality %：
C：Less than more than 0.010% 0.035%,
Si：Less than 0.10%,
Mn：Less than 0.35%,
P：Less than 0.035%,
S：Less than 0.020%,
N：Less than 0.010%,
Al：Less than more than 0.005% 0.030%, and
B：Less than more than 0.0001% 0.005%,
Remaining part is made up of Fe and inevitable impurity；
The ferrite average grain diameter of the tissue is less than 20 μm,
Wherein, BN and AlN is in a manner of meeting the condition of following formula (1) to separate out,
The n values of range of strain (strain range) 5~10% are more than 0.15,
Note
0 ＜ [BN]/[AlN]≤0.5 (1)
(in the formula (1), [BN] and [AlN] is respectively the BN and AlN represented with same units individual number density)
2. the cold-rolled steel sheet described in above-mentioned 1,
End on plate width, the position of 1/4 and central portion, the depth away from surface of steel plate is 10 μm
Opening position plate face { 111 } X ray random orientation intensity ratio be less than 5.0.
3. the cold-rolled steel sheet described in above-mentioned 1 or 2, the composition composition is further containing the choosing added up to below 1 mass %
1 from the group of Cu, Sn, Ni, Ca, Mg, Co, As, Cr, Mo, Sb, W, Ti, Nb, Pb, Ta, REM, V, Cs, Zr and Hf composition
More than kind.
4. the cold-rolled steel sheet any one of above-mentioned 1~3, further with the surface for being formed at the cold-rolled steel sheet
Plating epithelium.
5. the manufacture method of cold-rolled steel sheet, including：
Prepare the steel raw material with the composition composition described in above-mentioned 1 or 3,
To the steel raw material, implement the hot rolling for including finish rolling, so as to obtain hot rolled steel plate, the finish rolling is that finish rolling terminates temperature
Spend for the finish rolling under conditions of less than more than 800 DEG C 950 DEG C,
It is 30 DEG C/more than s, 110 DEG C/below s by the hot-rolled steel sheet water-cooling using average cooling rate,
The hot rolled steel plate after the water cooling is batched using coiling temperature as less than more than 600 DEG C 780 DEG C,
The oxide skin of the hot rolled sheet metal surface is removed,
Hot rolled steel plate cold rolling after the oxide skin is removed with more than 50% reduction ratio, so as to obtain cold-rolled steel sheet,
The cold-rolled steel sheet is annealed under conditions of being more than 650 DEG C in annealing temperature,
Wherein, the water cooling is within since the end of the hot rolling 3.0 seconds more than 0.5 second.
6. the manufacture method of above-mentioned 5 cold-rolled steel sheets recorded, before the finish rolling, with thin plate blanket heating (sheet
Bar heater) the heating steel raw material.
Invention effect
By means of the invention it is possible to obtain the cold-rolled steel sheet with excellent bendability.
Embodiment
[composition composition]
Next, illustrate the method for implementing the present invention.
In this invention it is important that cold-rolled steel sheet has mentioned component composition.Therefore, first, in the present invention with
The reasons why composition that aforesaid way limits steel forms illustrates.It should be noted that " % " table relevant with composition composition
State unless stated otherwise, otherwise refer to " quality % ".
C：0.010~0.035%
If C amounts are few, C precipitation driving force step-down is dissolved, therefore is dissolved C increases.If being dissolved C increases, it is easy to
Produce strain-aging, as a result, bendability reduces.Therefore, in the present invention, C amounts are set to more than 0.010%.C contains
The amount of having more preferably is set to more than 0.015%.On the other hand, if C amounts are more than 0.035%, cementite is in ferrite crystal grain
It is interior to generate superfluously, therefore yield strength rises, n values reduce, moreover, the hole production of the interface of ferrite and cementite
Raw site is increased, therefore bendability significantly deteriorates.Therefore, C amounts are set to less than 0.035%.C amounts are more preferably set
For less than 0.030%, less than 0.025% is further preferably set to.
Si：Less than 0.10%
Si is the element for the generation for suppressing cementite, and suppresses solid solution C cementite.Thus, by adding Si, and make
It is dissolved the increase of C amounts, as a result, the X ray random orientation intensity ratio of the plate face { 111 } of the ferrite texture in steel plate top layer can be made
Reduce.On the other hand, if Si amounts are more than 0.10%, it can exceedingly suppress the generation of cementite, solid solution C amount increases, prolong
Malleability reduces, and flexible (bendability) is deteriorated.Therefore, Si amounts are set to less than 0.10%.Si amounts are excellent
Choosing is set to less than 0.05%, is further preferably set to less than 0.03%.It should be noted that the lower limit of Si amounts is without special limit
It is fixed, but Si amounts are preferably set to more than 0.001%, more preferably it is set to more than 0.005%.
Mn：Less than 0.35%
Mn is the element for the effect for being dissolved in cementite, having the generation for suppressing thick cementite.It is foregoing in order to obtain
Effect, Mn amounts are preferably set to more than 0.01%, are more preferably set to more than 0.10%.On the other hand, if Mn amounts are more than
0.35%, then as Mn segregation, MnS are segregated, as a result, bendability is deteriorated.Therefore, Mn amounts are set to 0.35%
Below.Mn amounts are preferably set to less than 0.30%, are more preferably set to less than 0.25%.
P：Less than 0.035%
Because P is segregated in ferrite grain boundaries, so as to when bending machining, the production of the hole at ferrite grain boundaries can be promoted
Raw, amount is preferably lower.Therefore, P amounts are set to less than 0.035%.P amounts are preferably set to less than 0.025%.
On the other hand, the lower limit of P amounts is not particularly limited, and can be more than 0%, industrially, can be set to be more than 0%.But if P
Amount excessively reduces, then can cause increase, the rising of cost of refining time, thus P amounts be preferably set to 0.001% with
On.
S：Less than 0.020%
S is to be bonded in the present invention with Mn and form MnS element.If S amounts are high, MnS is largely generated, so as to work as
Promote the destruction at ferrite grain boundaries during bending machining.Therefore, in the present invention, S amounts are set to less than 0.020%.S contains
The amount of having is preferably set to less than 0.015%.On the other hand, the lower limit of S amounts is not particularly limited, and can be more than 0%, in industry
On, it can be set to be more than 0%.But if S amounts excessively reduce, increase, the rising of cost of refining time can be caused, because
This S amount is preferably set to more than 0.0005%.
N：Less than 0.010%
N is bonded with Al, B and forms AlN, BN.If N amounts are high, fine AlN is separated out superfluously, therefore n values drop
It is low.In addition, fine AlN turns into dislocation generating source, during cold rolling, can make the multiple slip of crystal grain become easy, being capable of shape
Organized before into fine and uniform annealing.As a result, during the annealing recrystallization carried out after cold rolling, the X ray of plate face { 111 } is random
Intensity is orientated to be deteriorated than increase, bendability.Therefore, N amounts can be lower, and in the present invention, N amounts are set to
Less than 0.010%.N amounts are preferably set to less than 0.004%.On the other hand, the lower limit of N amounts is not particularly limited, can be with
For more than 0%, industrially, can be set to be more than 0%.But if N amounts excessively reduce, refining time can be caused
Increase, the rising of cost, N amounts are preferably set to more than 0.0005%, are more preferably set to more than 0.0010%.
Al：Less than more than 0.005% 0.03%
Al promotes the discharge solid solution C out of ferrite crystal grain, and cementite is formed in crystal boundary.As a result, yield strength reduces, n values
Increase.In order to fully obtain the effect above, Al amounts are set to more than 0.005%.On the other hand, if Al amounts are excessive
Uprise, then can separate out fine AlN, Al and the oxide for being bonded and generating as the O of inevitable impurity, bending machining
Property reduce.Therefore, Al amounts are set to less than 0.030%.Al amounts are preferably set to less than 0.020%.
B：Less than more than 0.0001% 0.005%
B is bonded with N and forms BN, suppresses fine AlN precipitation.In addition, BN separates out by core of MnS, therefore, it is possible to
Reduce fine MnS amount.These precipitates are caught into ferrite crystal grain, as a result, as hole during bending machining
The nitride number of the ferrite grain boundaries of generating source is reduced, therefore bendability improves.In order to obtain the effect above, B is contained
Amount is set to more than 0.0001%.On the other hand, if B amounts are more than 0.005%, fine Fe23(CB)6Produced in crystal boundary,
Bendability reduces.Therefore, B amounts are set to less than 0.005%.B amounts are preferably set to less than 0.001%, more preferably
It is set to less than 0.0007%.
The cold-rolled steel sheet of the present invention includes the composition of the above, remaining part is made up of Fe and inevitable impurity.Need to illustrate
, so-called " remaining part is made up of Fe and inevitable impurity " refers to the situation in the action effect for not damaging the present invention
Under, including inevitable impurity, containing other micro- situations it is also included within the scope of the present invention.
Except above-mentioned element, cold-rolled steel sheet of the invention can also arbitrarily contain element as described below.
Formed selected from Cu, Sn, Ni, Ca, Mg, Co, As, Cr, Mo, Sb, W, Ti, Nb, Pb, Ta, REM, V, Cs, Zr and Hf
Group in more than a kind：Add up to less than 1%
Cu, Sn, Ni, Ca, Mg, Co, As, Cr, Mo, Sb, W, Ti, Nb, Pb, Ta, REM, V, Cs, Zr and Hf are to carrying
Useful element for highly corrosion resistant.Therefore, by the way that these element combinations are one kind or two or more and add, it is possible to increase steel
The corrosion resistance of plate.On the other hand, if the total amount of these elements be more than 1%, these elements grain boundaries be segregated from
And when bending machining, promote the hole generation from crystal boundary.Therefore, when adding these elements, amount will be amounted to and be set to 1%
Below.It should be noted that the total amount is preferably set to less than 0.5%.On the other hand, above-mentioned element is due to being any
Addition, therefore, the lower limit for amounting to amount is not particularly limited or 0%.But when the above-mentioned element of addition
When, from the viewpoint of the effect of corrosion resistance is improved, the total amount is preferably set to more than 0.05%, it is more excellent
Choosing is set to more than 0.1%.
More than, the composition composition of steel plate is illustrated, but in order to obtain the effect of institute's institute's phase by the present invention, only will
Composition composition be adjusted to above range be it is insufficient, it is necessary to by ferrite particle diameter, BN and AlN precipitation form and strain
The n values of scope 5~10% are set to above range.Thereby, it is possible to significantly improve the bendability of cold-rolled steel sheet.Hereinafter, to institute
The restriction reason for stating projects illustrates.
[ferrite average grain diameter]
Ferrite average grain diameter：Less than 20 μm
If ferrite average grain diameter is more than 20 μm, the strain in bending machining concentrates on ferrite grain boundaries, is easy to from iron
Ferritic crystal boundary ftractures, therefore bendability reduces.Therefore, in the present invention, ferrite average grain diameter is set to 20 μm
Below.Ferrite average grain diameter is preferably set to less than 15 μm.On the other hand, the lower limit of the ferrite average grain diameter is without special limit
It is fixed, if but ferrite average grain diameter it is too small, intensity be present and excessively rise, the Potential feasibility of ductility reduction.Therefore, iron element
Body average grain diameter is preferably set to more than 4 μm, is more preferably set to more than 8 μm.The ferrite average grain diameter can be by embodiment
The method measure of record.
It should be noted that in the present invention, it is preferred to that the metal structure of cold-rolled steel sheet is set into ferrite is single-phase.Here institute
" ferrite is single-phase " stated refers not only to count ferritic phase as 100% situation, in addition to area percent using area percent
For more than 95%, situation that to be essentially ferrite single-phase.
[precipitate]
0 ＜ [BN]/[AlN]≤0.5
In the cold-rolled steel sheet of the present invention, it is important that BN and AlN in a manner of meeting the condition of following formula (1) to analyse
Go out.
0 ＜ [BN]/[AlN]≤0.5 (1)
(in formula (1), [BN] and [AlN] is respectively the BN and AlN represented with same units individual number density)
If BN and AlN free energy of formation are compared, then it is assumed that AlN situation is more easily generated, in the heat of reality
Roll in process, using granular MnS as core, BN is preferentially generated.Moreover, at this moment, by forming thick BN, it can suppress and bend
Process the progress of associated cracking.In addition, carrying out N fixation by using B, AlN is separated out around the BN generated, therefore,
The rising of the yield strength as caused by AlN precipitation strength can be suppressed.In the present invention, in order to obtain these effects, with full
The mode of the condition of sufficient formula (1) controls BN dispersing morphology.
Formula (1) is the formula that the relation of the individual number density of the BN and AlN to being separated out in steel is defined.If for example, make
BN amount of precipitation is certain, then BN individual number density [BN] is smaller, and each BN separated out becomes thicker.Moreover, by expire
The mode of the condition of sufficient formula (1) controls BN and AlN individual number density, can promote precipitations of the AlN using BN as starting point, can reduce
Yield strength.In addition, by separating out BN in the above described manner, cementite is using BN preferentially to be analysed around the AlN that core separates out
Go out, therefore transgranular cementite can be reduced, further reduce yield strength.When [BN] and [AlN] value meet above-mentioned formula (1)
Relation when, be not particularly limited, can be set to arbitrarily be worth, for example, [BN] can be set to 0.0005~0.01/μm2.Need to illustrate
, here, plate width center for steel plate of above-mentioned [BN] and [AlN] value, the value of thickness of slab 1/4t opening positions, specifically
For can be determined by method described in embodiment.
[n values]
The n values of range of strain 5~10%：More than 0.15
Different from the small shaping of the dependent variables such as drawing and forming, in flexural deformation, due to assigning big strain to top layer, because
This is in higher range of strain, it is necessary to process hardening capacity height.Therefore, in the present invention, by the range of strain 5 of cold-rolled steel sheet~
10% n values (work hardening index) are set to more than 0.15.On the other hand, the upper limit of the n values is not particularly limited, and can be set to
Arbitrary value, but usually less than 0.4.It should be noted that n values described here are set to the center on the plate width of steel plate
Value.
[texture]
The X ray random orientation intensity ratio of plate face { 111 }：It is 5.0 following
In addition, in the cold-rolled steel sheet of the present invention, end on plate width, all positions of 1/4 and central portion
Place is put, the depth away from surface of steel plate is that the X ray random orientation intensity ratio of the plate face { 111 } of 10 μm of opening position is preferably set to
It is 5.0 following.
Texture (texture) on steel plate, it is known that by being orientated { 111 } //ND in plate face, so as to improve r values
The recrystallization texture control technology of (Lankford values).In deep drawing shaping, to being required on the direction parallel to plate face
High deformability, on the other hand, thickness of slab direction is needed to be unlikely to deform, therefore the steel plate with high r values is favourable.With this
Relatively, in brake forming, deformation constraint on the direction parallel to bending crest line be present.Therefore, in order that steel plate is relative
Deformed for crest line is bent on vertical direction (bending direction), if thinking constant volume, desirably the steel plate is in plate
There is high deformability on thick direction.Therefore, by by the X ray of { 111 } of the plate face of the ferrite texture in steel plate top layer
Random orientation intensity is less than 5.0 than control, can more fully be obtained for required cunning for thickness of slab side is upwardly-deformed
Move system.It should be noted that as described later, in hot-rolled process, the steel raw material by using the heating of thin plate blanket heating for finish rolling
Skin section and width end, the texture of the condition can be met in the overall scope of width.It is another
Aspect, the X ray random orientation intensity than lower limit be not particularly limited, can be set to arbitrarily be worth, but theoretic lower limit is
1, from the viewpoint of manufacture is upper, the X ray random orientation intensity ratio can be more than 1.2.
It should be noted that above-mentioned X ray random orientation intensity ratio can utilize three-dimensional crystal orientation distribution function (ODF：
Orientation distribution function) obtain.The residual stress of surface of steel plate is removed using chemical polishing
Afterwards, 3 pole figures measured are utilized with 5 ° of measuring space pole figures (pole figure) using X-ray diffraction (Schultz methods)
({ 110 }, { 200 }, { 211 }) can obtain ODF.It should be noted that random orientation intensity is than the X for measure object sample
Ray diffraction intensity is relative to the ratio between X-ray diffraction intensity of standard specimen (its crystal orientation is random).
[plating epithelium]
For the cold-rolled steel sheet of the present invention, can further have plating epithelium on its surface.By in surface of steel plate
Form plating epithelium, it is possible to increase the corrosion resistance of cold-rolled steel sheet.It should be noted that as the plating epithelium, can make
With the epithelium formed using arbitrary coating method, plating epithelium, hot dip alloyed plating skin are melted for example, can use
Film, plating epithelium etc..In addition, the material of the plating epithelium can be set to the various materials such as zinc, Zn based alloy.As can be adapted to make
The example of plating epithelium, galvanizing by dipping epithelium, alloyed hot-dip zinc-coated epithelium, electrogalvanizing epithelium, Zn-Ni alloy can be enumerated
Electroplate (Zn-Ni alloy electroplating) epithelium etc..
[manufacture method]
Next, the method for the cold-rolled steel sheet of the manufacture present invention is illustrated.The present invention cold-rolled steel sheet can according to
Under step manufacture.
(1) the steel raw material with mentioned component composition is prepared,
(2) to the steel raw material, the hot rolling for including finish rolling is implemented, so as to obtain hot rolled steel plate, the finish rolling is finish rolling temperature
Spend for the finish rolling under conditions of less than more than 800 DEG C 950 DEG C,
(3) it is 30 DEG C/more than s, 110 DEG C/below s by the hot-rolled steel sheet water-cooling using average cooling rate,
(4) hot rolled steel plate after the water cooling is batched using coiling temperature as less than more than 600 DEG C 780 DEG C,
(5) oxide skin of the hot rolled sheet metal surface is removed,
(6) the hot rolled steel plate cold rolling after the oxide skin is removed with more than 50% reduction ratio, so as to obtain cold-rolled steel
Plate,
(7) cold-rolled steel sheet is annealed under conditions of being more than 650 DEG C in annealing temperature.
Hereinafter, above-mentioned each operation is specifically illustrated.
[steel raw material]
In the present invention, above-mentioned steel raw material (plate slab) can be manufactured steel melting, casting using conventional method.It is described
Melting can be carried out using the arbitrary method such as converter, electric furnace, induction furnace.In addition, from the viewpoint of productivity ratio, the casting is excellent
Choosing is set to continuous casting process.In order to obtain the cold-rolled steel sheet that there is mentioned component to form, the composition composition of the steel raw material is set to
It is identical with the composition composition of above-mentioned cold-rolled steel sheet.
[hot rolling]
Next, by above-mentioned steel raw material hot rolling.The hot rolling is carried out after slab can also be reheated using heating furnace, separately
Outside, the purpose of temperature-compensating can also be in and is carried out after short time heating is carried out using heating furnace.The hot rolling can be
Hot rolling including roughing and finish rolling, or can also only carry out the hot rolling of finish rolling without roughing.
Final rolling temperature：Less than more than 800 DEG C 950 DEG C
If final rolling temperature is more than 950 DEG C, ferritic coarse grain is produced in a part, ferrite particle diameter produces deviation.
Therefore, final rolling temperature is set to less than 950 DEG C.On the other hand, if in ferrite area (Ar3Below transition point) rolled, then
Produce thick ferrite crystal grain.Therefore, in the present invention, final rolling temperature is set to more than 800 DEG C.It should be noted that this
Final rolling temperature described in text refers to finish rolling outlet side temperature.
Utilize the heating of thin plate blanket heating
, preferably will be for thin plate blanket heating before the finish rolling in above-mentioned hot rolling it should be noted that in the present invention
The steel raw material heating of finish rolling.Thereby, it is possible to the Temperature Distribution on plate width is become uniform, as a result, can obtain time
And the scope of plate width entirety is interior, the X ray random orientation intensity of plate face { 111 } is than the texture for less than 5.0.Need
Bright, when carrying out roughing before finish rolling, above-mentioned heating can enter to sheet billet (thick rod (rough bar)) after roughing etc.
OK.
As above-mentioned thin plate blanket heating, when above-mentioned heating can be carried out, arbitrary heater can be used.Above-mentioned sheet billet
Heater can be the heater integrally heated to the width of steel raw material (or thick rod), or or only right
(edge heater) of width end heat.But become uniform viewpoint from the Temperature Distribution made on plate width
Consider, preferably use can heat the heater of the width entirety of steel raw material.As the width side that can heat steel raw material
To the heater of entirety, preferably using for example (coil of heating is rolled into tubular, steel raw material to solenoid type induction heating apparatus
It is inductively heated by wherein).When using solenoid type induction heating apparatus, the skin section of steel plate and width end
Any one be heated.
[water cooling]
Hot rolling terminates the time started to water cooling：Within 3.0 seconds more than 0.5 second
After above-mentioned hot rolling, start the water cooling of gained hot rolled steel plate.If the hot rolling terminates the time started to the water cooling
Less than 0.5 second, then an adequate amount of BN will not be separated out, as a result, fine AlN is largely generated so as to which yield strength increases.Therefore, exist
In the present invention, hot rolling is terminated to the time that water cooling starts to be set to more than 0.5 second.The time that hot rolling terminates to water cooling to start is more excellent
Choosing is set to more than 0.8 second.On the other hand, if the time started to the water cooling is more than 3.0 seconds, the BN generated quantity increases
Greatly, it is easy to produce cracking, the hole using BN as starting point.Therefore, by hot rolling terminate to the time that water cooling starts be set to 3.0 seconds with
It is interior.Hot rolling terminates to the time that water cooling starts more preferably to be set within 2.5 seconds.
Average cooling rate：30 DEG C/more than s, 110 DEG C/below s
Precipitation form of the cooling velocity to BN in the water cooling has considerable influence.Therefore, in the present invention, it is important
It is to control the average cooling rate in the water cooling.If average cooling rate is less than 30 DEG C/s, BN growing amount is excessive, curved
Bent processability is deteriorated.Therefore, average cooling rate is set to 30 DEG C/more than s.The average cooling rate is preferably set to 50 DEG C/s
More than, more preferably it is set to 70 DEG C/s.On the other hand, if average cooling rate is more than 110 DEG C/s, existing stably to ensure
The Potential feasibility of desired coiling temperature.Therefore, the average cooling rate is set to 110 DEG C/below s.
[batching]
Coiling temperature：Less than more than 600 DEG C 780 DEG C
After the end of above-mentioned water cooling, hot rolled steel plate is rolled into coil of strip.In this invention it is important that by batching now
Temperature is set to less than more than 600 DEG C 780 DEG C.If coiling temperature is less than 600 DEG C, nitride can not be fully set to become thick,
It cannot get the precipitation form of BN, AlN specified in the present invention.Therefore, coiling temperature is set to more than 600 DEG C.The coiling temperature
It is preferably set to more than 630 DEG C.On the other hand, if coiling temperature is more than 780 DEG C, generation becomes thick AlN, works as bending machining
When, promote the progress to ftracture.Therefore, coiling temperature is set to less than 780 DEG C.The coiling temperature is preferably set to less than 750 DEG C,
More preferably it is set to less than 720 DEG C.
[oxide skin removing]
Next, the oxide skin formed on the surface of above-mentioned hot rolled steel plate is removed.The method that oxide skin removes is without special
Limit, carried out using arbitrary method, generally carried out using pickling.The pickling is preferably entered using continuous acid-washing production line
OK.When carrying out oxide skin removing using continuous acid-washing production line, pickling can be carried out continuously while by coil of strip unwinding.
[cold rolling]
Reduction ratio：More than 50%
Next, the hot rolled steel plate cold rolling after the oxide skin is removed is so as to obtaining cold-rolled steel sheet.If the cold rolling
The reduction ratio is less than 50%, then the degree of finish deficiency on steel plate top layer, by roll it is introduced should tail off, therefore inhibit
The rearrangement recrystallization of dislocation in subsequent annealing.And, as a result, ferrite particle diameter becomes thick.Therefore, in the present invention
In, the reduction ratio in the cold rolling is set to more than 50%.The reduction ratio is preferably set to more than 55%.On the other hand, it is described
The upper limit of reduction ratio is not particularly limited, if but reduction ratio it is too high, plate shape deteriorates sometimes, it is therefore preferable that be set to less than 98%,
More preferably it is set to less than 95%.
[annealing]
Annealing temperature：More than 650 DEG C
Next, cold-rolled steel sheet obtained from carrying out above-mentioned cold rolling is annealed.In this invention it is important that by described in
Temperature during annealing is set to more than 650 DEG C.If annealing temperature is less than 650 DEG C, recrystallization does not complete, therefore by annealing temperature
It is set to more than 650 DEG C.The annealing temperature is preferably set to more than 680 DEG C, is more preferably set to more than 700 DEG C.On the other hand, if moving back
Fiery temperature is more than 900 DEG C, then produces austenite so as to turn into mixed crystal, therefore annealing temperature is preferably set to less than 900 DEG C, more preferably
Less than 850 DEG C are set to, is further preferably set to less than 800 DEG C.It should be noted that the annealing can also utilize continuous annealing
Carried out with any means in box annealing (batch annealing (batch annealing)).Described in being carried out using continuous annealing
During annealing, Wetted constructures can also be carried out in continuous annealing production line.
[skin pass rolling]
Although not influenceed on the effect of the present invention, after above-mentioned annealing, skin pass rolling can be arbitrarily carried out.It is if described
The reduction ratio of skin pass rolling be less than 0.5%, then elongation at yield point will not disappear, if in addition, reduction ratio be more than 1.5%, steel
Generation hardening, therefore the reduction ratio of the skin pass rolling is preferably set to less than more than 0.5% 1.5%.
[thickness of slab]
The thickness of slab of the cold-rolled steel sheet of the present invention is not particularly limited, and can be set to arbitrary thickness.But make from building materials
From the viewpoint of, if being exceedingly thinned, the Potential feasibility rigidly reduced be present, it is therefore preferable that thickness of slab is set into 0.1mm
More than.On the other hand, if exceedingly thickening, the Potential feasibility of bendability variation be present, therefore preferably set thickness of slab
For below 4.0mm, below 3.0mm is more preferably set to.
In addition, in the present invention, plating can also be implemented by the cold-rolled steel sheet manufactured to operation more than carrying out,
Plating epithelium is formed in surface of steel plate.For example, as plating, it is possible to implement galvanizing by dipping is handled and formed in surface of steel plate
Galvanizing by dipping epithelium, can also be after galvanizing by dipping processing, implementation Alloying Treatment, so as to form alloyed hot-dip zinc-coated skin
Film.At this time it is also possible to galvanizing by dipping and annealing are carried out in a production line.In addition it is also possible to utilize Zn-Ni alloy electroplating
Deng plating, plating epithelium is formed.When implementing plating, the skin pass rolling can also be carried out after the generation of plating epithelium.
Embodiment
Next, the present invention is further elaborated with based on embodiment.Following embodiment is to show that the present invention's is preferred
An example, the present invention not by any restriction of the embodiment.
Firm A~X the vacuum meltings of sample that the composition recorded with table 1 is formed, obtain slab.By the slab hot rolling
Afterwards, water cooling is carried out, implements the processing that simulation is batched.Obtained hot rolled steel plate is subjected to pickling processes so as to which surface scale be removed
After going, cold rolling is carried out in a manner of final thickness of slab turns into 1.0mm.Next, implementing continuous annealing, pickling is carried out.It is described everywhere
Reason is implemented under the conditions of shown in table 2.It should be noted that in a part of example, before the finish rolling of hot-rolled process, thin plate is used
Blanket heating heats thick rod.As the thin plate blanket heating, solenoid type induction heating apparatus is used.
The respective middle collection test film of cold-rolled steel sheet obtained by aforesaid operations are carried out, implement metal using following methods
Observation, tension test and the bend test of tissue.
[ferrite average grain diameter]
Pair thickness of slab Cross section polishing parallel with the rolling direction of the cold-rolled steel sheet of gained uses nital into minute surface
After exposing tissue, light microscope macrograph is shot with 100 times of multiplying power.In gained photo, in thickness of slab side
On to, rolling direction, more than 50 μm of interval is calculated as with real-time length and draws 15 lines respectively, to the intersection point of crystal boundary and line
Number is counted.Line segment length using the number of whole piece line length divided by intersection point as each ferrite crystal grain, is multiplied by
1.13 so that obtain ASTM (American Society for Testing and Materials) ferrite average grain diameter.
[BN and AlN individual number density]
The number for determining plate width central, thickness of slab 1/4t opening positions the BN and AlN of steel plate as steps described below is close
Degree.First, the rolling direction with gained cold-rolled steel sheet is put down using a small amount of perchloric acid ethanol solution added with butyl cellosolve
Capable thickness of slab section carries out electrobrightening.Next, by carbon extract complex method by precipitate extract on carbon film so as to making
Sample, the sample is observed with transmission electron microscope (TEM).Determine every 400 μm2BN and AlN number, will be regarded at 5
The average individual number density as each precipitate of the value of Yezhong measure.
[texture]
From the end on the cold-rolled steel sheet of gained, plate width, each position of 1/4 and central portion, collection observation
Use sample.After the plate face of each sample is removed into 10 μm with chemical polishing, surveyed using X-ray diffraction (Schultz methods) with 5 ° of intervals
Determine pole figure (pole figure).Three-dimensional crystal distribution of orientations is obtained using 3 pole figures ({ 110 }, { 200 }, { 211 }) measured
Function (ODF), obtain by { 111 } cumulant (amount of accumulation) of random orientation intensity than expression.
[n values]
From the plate width center of obtained cold-rolled steel sheet, gather to be used as drawing as parallel direction relative to rolling direction
No. 5 tension test sheets of JIS (JIS Z 2201) in direction are stretched, tension test is carried out according to JISZ2241 regulation, calculate 5~
The n values of 10% range of strain.
[critical bend radius]
From the end on the plate width of obtained cold-rolled steel sheet, the position of 1/4 and central portion, chi is gathered
The very little banded test film for 100mm × 35mm.By the crest line of bending rolling Vertical Square be bent upwards in a manner of to described
The length direction center of test film carries out bend test, so as to evaluate the bendability of cold-rolled steel sheet.In the bend test
In, use 90 ° of bend test fixture of drift angle.Change the radius of curvature of the drift angle of bend test fixture, obtain in test film table
Face does not find the minimum test fixture front-end radius (R) of crackle, and obtained radius (R) divided by thickness of slab (t) face so as to calculate
Boundary's bending radius (R/t).The value is smaller, then has more excellent bendability.In addition, for by 90 ° bending without
For the test film cracked, the test film of 90 ° of bendings is clamped with bench vice, 180 ° is further carried out and completely attaches to bending,
Will be in the contact bending, the critical bend radius for the test film also not cracked is set to 0.
Each measured value obtained using above method is shown in table 3.Result as shown in Table 3 is understood, for meeting this hair
For the cold-rolled steel sheet of bright condition, critical bend radius (R/t) is less than 0.5, and brake forming is excellent.Need what is illustrated
It is, for the value of critical bend radius, it was observed that the trend being deteriorated than width end for width midway portion, but this is
Due to being easy in temperature at the width end of reduction, BN amount of precipitation reduces.
Table 1
* remaining part is Fe and inevitable impurity
Table 2
* 1 heating being carried out before finish rolling, using thin plate blanket heating
* 2 hot rollings terminate the time started to cooling
Table 3
* 1 range of strain 5-10% n values.
Claims (6)
1. cold-rolled steel sheet, there are following compositions to form and organize for it,
The composition composition is contained in terms of quality %：
C：Less than more than 0.010% 0.035%,
Si：Less than 0.10%,
Mn：Less than 0.35%,
P：Less than 0.035%,
S：Less than 0.020%,
N：Less than 0.010%,
Al：Less than more than 0.005% 0.030%, and
B：Less than more than 0.0001% 0.005%,
Remaining part is made up of Fe and inevitable impurity；
The ferrite average grain diameter of the tissue is less than 20 μm,
Wherein, BN and AlN is in a manner of meeting the condition of following formula (1) to separate out,
The n values of range of strain 5~10% are more than 0.15,
0 ＜ [BN]/[AlN]≤0.5 (1)
In the formula (1), [BN] and [AlN] is respectively the BN and AlN represented with same units individual number density.
2. cold-rolled steel sheet according to claim 1, end on plate width, each position of 1/4 and central portion
Place, the depth away from surface of steel plate is that the X ray random orientation intensity ratio of the plate face { 111 } of 10 μm of opening position is less than 5.0.
3. cold-rolled steel sheet according to claim 1 or 2,
Composition composition further containing add up to below 1 mass % selected from Cu, Sn, Ni, Ca, Mg, Co, As, Cr, Mo,
More than a kind in the group of Sb, W, Ti, Nb, Pb, Ta, REM, V, Cs, Zr and Hf composition.
4. according to cold-rolled steel sheet according to any one of claims 1 to 3, further there is the table for being formed at the cold-rolled steel sheet
The plating epithelium in face.
5. the manufacture method of cold-rolled steel sheet, including：
Prepare the steel raw material with the composition composition described in claim 1 or 3,
To the steel raw material, implement the hot rolling for including finish rolling, so as to obtain hot rolled steel plate, the finish rolling is that finish rolling end temp is
Finish rolling under conditions of less than more than 800 DEG C 950 DEG C,
It is 30 DEG C/more than s, 110 DEG C/below s by the hot-rolled steel sheet water-cooling using average cooling rate,
The hot rolled steel plate after the water cooling is batched using coiling temperature as less than more than 600 DEG C 780 DEG C,
The oxide skin of the hot rolled sheet metal surface is removed,
Hot rolled steel plate cold rolling after the oxide skin is removed with more than 50% reduction ratio, so as to obtain cold-rolled steel sheet,
The cold-rolled steel sheet is annealed under conditions of being more than 650 DEG C in annealing temperature,
Wherein, the water cooling is within since the end of the hot rolling 3.0 seconds more than 0.5 second.
6. the manufacture method of cold-rolled steel sheet according to claim 5, before the finish rolling, heated with thin plate blanket heating
The steel raw material.
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| JP2015-139054 | 2015-07-10 | ||
| JP2015139054 | 2015-07-10 | ||
| PCT/JP2016/003221 WO2017010064A1 (en) | 2015-07-10 | 2016-07-06 | Cold rolled steel sheet and method for producing same |
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| US20230002846A1 (en) * | 2019-12-19 | 2023-01-05 | Nippon Steel Corporation | Steel sheet and manufacturing method thereof |
| CN112458361A (en) * | 2020-10-28 | 2021-03-09 | 邯郸钢铁集团有限责任公司 | Cold-rolled low-carbon steel capable of reducing surface orange peel defects and production method thereof |
| KR20230092609A (en) * | 2021-12-17 | 2023-06-26 | 주식회사 포스코 | Cold-rolled steel sheet with excellent weldability and method of manufacturing thereof |
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- 2016-07-06 JP JP2016562612A patent/JP6119928B1/en active Active
- 2016-07-06 KR KR1020187001667A patent/KR20180018804A/en not_active Ceased
- 2016-07-07 TW TW105121652A patent/TWI596217B/en not_active IP Right Cessation
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114641586A (en) * | 2019-11-13 | 2022-06-17 | 日本制铁株式会社 | Hot rolled steel |
| CN114641586B (en) * | 2019-11-13 | 2023-11-07 | 日本制铁株式会社 | hot rolled steel |
Also Published As
| Publication number | Publication date |
|---|---|
| JP6119928B1 (en) | 2017-04-26 |
| JPWO2017010064A1 (en) | 2017-07-13 |
| TW201708559A (en) | 2017-03-01 |
| KR20180018804A (en) | 2018-02-21 |
| CN107849654B (en) | 2019-08-20 |
| WO2017010064A1 (en) | 2017-01-19 |
| TWI596217B (en) | 2017-08-21 |
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