CN106795609B - Drawing steel plate for tanks and its manufacturing method - Google Patents
Drawing steel plate for tanks and its manufacturing method Download PDFInfo
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- CN106795609B CN106795609B CN201580055679.7A CN201580055679A CN106795609B CN 106795609 B CN106795609 B CN 106795609B CN 201580055679 A CN201580055679 A CN 201580055679A CN 106795609 B CN106795609 B CN 106795609B
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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
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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
- C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
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Abstract
A kind of drawing steel plate for tanks includes C, Sol.Al, B as chemical component, includes the ferrite and nodular cementite that average grain diameter is 2.7~4.0 μm as microstructure.Tension test is carried out after implementing 1 hour ageing treatment to the steel plate at 100 DEG C, at this point, yield strength is 360~430MPa, percentage of total elongation is 25~32%, and elongation at yield point 0%, yield ratio is 80~87%.
Description
Technical field
The present invention relates to drawing steel plate for tanks and its manufacturing methods, more specifically, are related to the high intensity cold of ironed can
Rolled steel plate and its manufacturing method.
The application is claimed priority based on October 17th, 2014 in Japanese patent application 2014-213239 proposed,
Here cite its content.
Background technique
D type battery~N-type cell (battery of international standard size 20~1), button cell, large-scale hybrid-power battery etc.
Battery can, various containers be by cold-rolled steel sheet or as needed implement plating processing plated steel sheet it is (hereinafter also referred to cold
Rolled steel plate) drawing process (stamping) and manufacture.
In the drawing process, it is desirable that dimensional accuracy is high, inhibit the abrasion of stamping die and productivity is high.Therefore, as confession
The excellent soft cold rolling of press formability as drawing process and deep drawability is utilized in the cold-rolled steel sheet of drawing process
Steel plate.
On the other hand, in recent years, also constantly sought for the cold-rolled steel sheet of drawing process in order to realize being thinning for ironed can
Ask further increasing for intensity.For example, in recent years, with the development of electronic equipment, it is desirable that further increase the capacity of battery.
But size has been determined in the shape of battery in specification.Thus, in order to increase battery active material loading,
Need to increase the volume (internal volume of ironed can) of inside battery.Moreover, needing to increase the internal volume of ironed can by drawing
The cold-rolled steel sheet of tank is thinning ((gauge down) is thinned in thickness).But in the case where cold-rolled steel sheet thickness is thinned, have
When ironed can intensity it is inadequate.The especially tank bottom of ironed can, processing dependent variable when due to drawing process is few, can not
Expect processing hardening.Therefore, it in order to improve the intensity of ironed can, particularly the resistance to interior external pressure strength of tank bottom, needs to improve cold rolling
The intensity of steel plate.
The cold-rolled steel sheet of ironed can, as described above, it is desirable that press formability is excellent, and is high intensity.But it improves
Press formability and raising intensity can be described as the technical task runed counter to each other.It is incited somebody to action even if can be improved the intensity of cold-rolled steel sheet
Cold-rolled steel sheet is thinning, and is also envisioned that the decline of the percentage of total elongation EL of the cold-rolled steel sheet, the i.e. decline of press formability.Example
Such as, even if improving the intensity of cold-rolled steel sheet, in the case where carrying out multistage processing as drawing process, also due to
The trunk top processing dependent variable of ironed can becomes greatly, therefore cold-rolled steel sheet presence cannot preferably carry out punch process
Possibility.In this way, about ironed can cold-rolled steel sheet, it is not easy to accomplish to make high-intensitive and excellent press formability and deposit.
Than that described above, in ironed can cold-rolled steel sheet, it is necessary to inhibit that elongation strain (striped occurs in drawing process
The surface defect of style).In case of elongation strain, then the thicker part of plate thickness can be formed in tank circumferential surface and tank bottom and (do not sent out
The part of raw elongation strain) and relatively thin part (part that elongation strain has occurred).That is, in tank circumferential surface and tank bottom shape
At bumps.If battery can (ironed can) has such concaveconvex shape, the contact resistance of battery can and cell active materials
Become larger, therefore not preferably.In addition, if ironed can has such concaveconvex shape, it is likely that under the extensional rigidity of ironed can
Drop, the resistance to interior external pressure strength of ironed can also decline.Thus, for ironed can cold-rolled steel sheet, in addition to requiring high-intensitive and punching press
Other than having excellent formability, also require that elongation strain does not occur after drawing process.Furthermore it in the following description, will be in drawing
There is a situation where elongation strains to be known as " non-St-St is excellent " after processing.
Furthermore yield point elongation when elongation strain is due to steel plate deformed is (just in the change smaller than yield point after surrender
The stead deformation carried out under form drag) and occur.The elongation strain can be by roll steel plate with slighter compress rate
Skin-pass (skin pass rolling) inhibits.But the steel of strain-age hardening is generated implementing skin-pass to steel plate
Plate, with time going by, elongation strain inhibitory effect reduce.
In the past, in order to inhibit elongation strain, as ironed can cold-rolled steel sheet, the Ultra-low carbon added with niobium (Nb) has been used
Steel, the mild steel for being added with boron (B).For example, being added with IF representated by ultra-low-carbon steel (Nb-SULC) of Nb etc.
(Interstitial Free) steel can prevent the generation of elongation strain due to being difficult to generate age-hardening.But add
Added with the ultra-low-carbon steel of Nb, since its composition of steel is limited, therefore, it is difficult to improve the intensity of steel.On the other hand, added with the low of B
Carbon steel, since the B in steel and nitrogen (N) are combined, the age-hardening due to N is suppressed.But it should be added with the low-carbon of B
Steel, it is also desirable to inhibit the age-hardening as caused by the solid solution carbon (C) in steel.Thus, the mild steel added with B, by by steel
After plate continuous annealing, implements Wetted constructures using box annealing, the solid solution C in steel is reduced, to prevent the hair of elongation strain
It is raw.For example, needing the low temperature by steel plate at 400 DEG C or so in the above-mentioned Wetted constructures realized by box annealing
After lower carry out soaking, by steel plate slow cooling.Furthermore in the following description, " CAL will be known as using the annealing of continuous annealing line
(Continuous Annealing Line)".In addition, the Wetted constructures realized by box annealing are known as " BAF-
OA (Box Annealing Furnace-Over Aging) ".
In the BAF-OA, in order to carry out above-mentioned soaking and slow cooling, the processing time in or so week is needed.Cause
And when carrying out BAF-OA, the productivity of ironed can cold-rolled steel sheet declines significantly.If it is possible to not implement
BAF-OA and manufacture that high-intensitive, press formability is excellent, non-St-St also excellent ironed can cold-rolled steel sheet, then producing
It is very useful in industry.
For example, patent document 1 discloses a kind of drawing steel plate for tanks.Drawing steel plate for tanks disclosed in patent document 1 is
The aluminum killed steel of low-carbon containing B, C content are 0.045~0.100%.It is described in the patent document 1: in order to inhibit steel
The ceiling restriction of C content is 0.100% by the case where plate hardening declines to drawing process.
Citation
Patent document
Patent document 1: No. 4374126 bulletin of Japan's patent
Summary of the invention
Although patent document 1 discloses a kind of drawing steel plate for tanks, drawing steel plate for tanks disclosed in patent document 1 is
Soft cold-rolled steel sheet.Thus, by the steel plate carried out thickness be thinned in the case where, with ironed can resistance to interior external pressure strength
A possibility that decline.In addition, drawing steel plate for tanks disclosed in patent document 1, in the case where BAF-OA is omitted, it is difficult to
Inhibit elongation strain.In this way, patent document 1 do not disclose also there is no suggestion that in order to realize thickness be thinned and cold-rolled steel sheet is high-strength
Degreeization and the content for also making press formability and non-St-St other than the high intensity while improving.That is, existing
In technology, by ensuring intensity with being more than 0.15% higher C content, and without box annealing, in ironed can
With elongation strain cannot be inhibited in steel plate after ageing treatment.Furthermore the taggers tin of defined in JIS G3303
(blik) C content in ingredient is 0.13% or less.
The present invention has been made in view of the above-described circumstances, and project is to can provide high-intensitive, punching press without implementing BAF-OA
It has excellent formability, non-St-St also excellent ironed can cold-rolled steel sheet.
The gist of the invention is as follows.
(1) the drawing steel plate for tanks that a kind of technical solution of the invention is related to,
As chemical component, contained in terms of quality %
C: more than 0.150% and for 0.260% or less,
Sol.Al:0.005~0.100%,
B:0.0005~0.02%,
Si:0.50% or less,
Mn:0.70% or less,
P:0.070% or less,
S:0.05% or less,
N:0.0080% or less,
Nb:0.003% or less,
Ti:0.003% hereinafter,
Surplus includes Fe and impurity,
Boron content and nitrogen content in the chemical component satisfaction 0.4≤B/N≤2.5 in terms of quality %,
As the microscopic structure of the steel plate, the ferrite and nodular cementite that are 2.7~4.0 μm comprising average grain diameter,
The plate thickness of the steel plate is 0.15~0.50mm,
Progress draw direction is parallel with rolling direction after the steel plate to be implemented to 1 hour ageing treatment at 100 DEG C
Tension test, by the yield strength obtained by the tension test by units MPa be denoted as YP, percentage of total elongation by unit % be denoted as EL,
When elongation at yield point is denoted as YP-EL by unit %, yield ratio is denoted as YR by unit %,
The YP is 360~430MPa,
The EL is 25~32%,
The YP-EL is 0%,
The YR is 80~87%.
(2) in the drawing steel plate for tanks described in above-mentioned (1), when the plate thickness is more than 0.20mm and is 0.50mm or less
The EL can be 27~32%.
It (3), can be configured with plating on the surface of the steel plate in the drawing steel plate for tanks described in above-mentioned (1) or (2)
Ni layers, Ni diffusion coating, plating Sn layers and TFS coating at least one of coating.
(4) manufacturing method of drawing steel plate for tanks described in a kind of above-mentioned (1) or (2), has:
Obtain the steel process processed of the slab with the chemical component；
The slab is heated to 1000 DEG C or more by hot-rolled process, the process, finish rolling is carried out at 840~950 DEG C, in essence
Roller repairing batch at 500~720 DEG C obtaining hot rolled steel plate；
Once cold rolling process, the process implement the once cold rolling that accumulative reduction ratio is more than 80% to the hot rolled steel plate, from
And obtain once cold rolling steel plate；
Annealing operation, the process implement continuous annealing to obtain annealed sheet steel, and the continuous annealing is will be described primary
Cold-rolled steel sheet is heated up with 10~40 DEG C/sec of average heating speed, carries out soaking within the temperature range of 650~715 DEG C, thereafter,
With 5~80 DEG C/sec of cooling annealing of average cooling rate in 500~400 DEG C of section；With
Skin-pass process, the process will not have to implement the annealed sheet steel of Wetted constructures after the annealing operation
Skin-pass is carried out with 0.5~5.0% accumulative reduction ratio, to obtain skin-pass steel plate.
(5) in the manufacturing method of the drawing steel plate for tanks described in above-mentioned (4), it can also be also equipped with plating process, the work
Sequence after the skin-pass process to the skin-pass steel plate implement plating Ni processing, Ni diffusion plating, plating Sn processing and
TFS plating at least one of processing.
Above-mentioned technical proposal according to the present invention, can provide without implementing BAF-OA high-intensitive, press formability is excellent,
Non- St-St also excellent drawing steel plate for tanks.The press formability of the steel plate is excellent, is able to suppress the generation of elongation strain,
It can be realized thickness to be thinned.
Detailed description of the invention
Fig. 1 is accelerated ag(e)ing treated the stretch test result of previous drawing steel plate for tanks, and being will be near yield point
The load-deformation curve enlargedly shown.
Fig. 2 be the ironed can cold-rolled steel sheet that one embodiment of the present invention is related to accelerated ag(e)ing treated stretch examination
It tests as a result, being the load-deformation curve for nearby enlargedly showing yield point.
Fig. 3 is the optical microscope photograph for indicating the microscopic structure of previous ironed can cold-rolled steel sheet.
Fig. 4 is the optical microscope photograph for indicating the microscopic structure of ironed can cold-rolled steel sheet of the present embodiment.
Fig. 5 is the curve graph of the C content (%) for indicating cold-rolled steel sheet and the relationship of elongation at yield point YP-EL (%).
Fig. 6 is the curve graph of the C content (%) for indicating cold-rolled steel sheet and the relationship of percentage of total elongation EL (%).
Specific embodiment
Hereinafter, being described in detail to the preferred embodiments of the present invention.But the present invention is not only limited in this reality
Composition disclosed in mode is applied, can be made various changes without departing from the spirit and scope of the invention.In addition, for following
Numerical definiteness range, lower limit value and upper limit value include in this range.It is expressed as the numerical value of " being more than " or " being lower than ", the value is not
In numberical range." % " that the content of each element is related to means " quality % ".
The present inventor investigates and studies to the characteristic of the steel plate (hereinafter referred to as cold-rolled steel sheet) of ironed can, obtains
Opinion (i) below~(iv).Firstly, being illustrated to opinion (i) and (ii).
(i) in cold-rolled steel sheet of the present embodiment, if being set as C content more than 0.150, steel passes through in steel
Solid solution C and solution strengthening, the yield strength YP of cold-rolled steel sheet are improved.The surrender of rolling direction (direction L) after natrual ageing
Intensity YP reaches the 360MPa or more higher than the yield strength of previous ironed can cold-rolled steel sheet.Therefore, if it is cold using this
Rolled steel plate can also obtain the excellent ironed can of resistance to interior external pressure strength even if then thickness is thinned.
(ii) in cold-rolled steel sheet of the present embodiment, even if C content is increased to exceed 0.150, if by CAL
The average heating speed of (continuous annealing) is set as 10~40 DEG C/sec, and annealing temperature (soaking temperature), which is set as recrystallization, terminates temperature
Du or more and ferrite single-phase region temperature (such as 650~715 DEG C), by the average cooling in 500~400 DEG C of section thereafter
Speed is set as 5~80 DEG C/sec, then can also obtain even if there is solid solution C, non-St-St also excellent cold-rolled steel sheet in steel.
Stress-strain line chart near the yield point of previous ironed can cold-rolled steel sheet is shown in Fig. 1.It is shown in Fig. 2
Yield point (0.2% endurance (the offset yield strength σ of ironed can cold-rolled steel sheet of the present embodiment0.2)) answering nearby
Power-strain line chart.The C content of the cold-rolled steel sheet for tension test of Fig. 1 is 0.056 mass %, Fig. 2 for tension test
The C content of cold-rolled steel sheet is 0.153 mass %.The cold-rolled steel sheet of Fig. 1 and Fig. 2 be meet it is aftermentioned of the present embodiment
It is produced under conditions of the manufacturing method of cold-rolled steel sheet.Specifically, not implementing BAF- after implementing CAL under the above conditions
OA and the cold-rolled steel sheet for producing Fig. 1 and Fig. 2.It has been made to have by the cold-rolled steel sheet produced and put down with the direction L (rolling direction)
No. 5 tensile samples of JIS of capable parallel portion.Accelerated ag(e)ing processing is implemented to the tensile sample produced.Specifically, making
For accelerated ag(e)ing processing, 1 hour ageing treatment is implemented at 100 DEG C to each tensile sample.Accelerated ag(e)ing processing is suitable
In the substantially saturated timeliness of natrual ageing.It is real in room temperature (25 DEG C) and atmosphere using accelerated ag(e)ing treated tensile sample
Tension test is applied, the stress-strain line chart of Fig. 1 and Fig. 2 has been obtained.
In the low previous cold-rolled steel sheet (Fig. 1) of C content, yield point decline occurs, produces yield point elongation YP-
EL.This is due to as follows: even if applying stress from outside, also due to solid solution C bring Ke Shi (Cottrell) effect, until bending
Dislocation is not moved and (is fixed) until clothes point, and is moved quickly from solid solution C liberation in surrender point dislocation.Moreover, with
Toward cold-rolled steel sheet (Fig. 1) in, be also repeated the fixation and liberation of the dislocation caused by Ke Shi effect after surrender, therefore produce
Raw yield point elongation YP-EL.
In contrast, in the high cold-rolled steel sheet of the present embodiment (Fig. 2) of C content, yield point is not confirmed
Decline, does not generate yield point elongation YP-EL.The stress-strain line chart for observing Fig. 2, not with the stress-strain line chart of Fig. 1
Together, interval is marked and drawed before reaching yield point significantly shorten (stress variation and strain variation per unit time becomes smaller).That is, at this
In the cold-rolled steel sheet (Fig. 2) that embodiment is related to, when applying stress from outside, even before yield point, also locally starting
Plastic deformation, produces the specific phenomenon for not observing yield point elongation YP-EL as shown in Figure 1.
Then, for the cold-rolled steel sheet of Fig. 1 and Fig. 2, it is (parallel with rolling direction that the section L is observed using optical microscopy
Section) in microscopic structure.Fig. 3 is the microstructure image for the section L of the cold-rolled steel sheet of the tension test of Fig. 1, and Fig. 4 is
For the microstructure image in the section L of the cold-rolled steel sheet of the tension test of Fig. 2.
In figs. 3 and 4, white tissue is ferrite 10, and the tissue of black is nodular cementite 20.From Fig. 3 and Fig. 4
Observable goes out, and the microscopic structure of the cold-rolled steel sheet of Fig. 3 and Fig. 4 is the main tissue comprising ferrite and nodular cementite.But
The ferrite average grain diameter of the cold-rolled steel sheet of the high Fig. 4 of C content is smaller than the ferrite average grain diameter of the cold-rolled steel sheet of Fig. 3
4.0 μm or less.It is comprising thick compared with the cold-rolled steel sheet of Fig. 3 in addition, can see that the ferritic structure of the cold-rolled steel sheet of Fig. 4
The mangcorn of big grain and microfine.
Tension test and structure observation more than considering as a result, cold-rolled steel sheet of the present embodiment (C content is high
Cold-rolled steel sheet) specific phenomenon near yield point that shows can be presumed as follows.In cold rolling of the present embodiment
In steel plate (the high cold-rolled steel sheet of C content), with C content compared with low cold-rolled steel sheet, the average grain diameter of ferrite grain becomes smaller, iron element
Body grain easily becomes mangcorn.That is, the feelings to deform in the cold-rolled steel sheet with microscopic structure specific to present embodiment
Under condition, since the coarse ferrite grain among the ferrite grain of mangcorn, proactively start to deform before yield point, be later than thick
Big ferrite grain and the deformation for starting fine ferrite grain.In this way, cold-rolled steel sheet of the present embodiment, from outside
When by stress, since the big ferrite of partial size successively deform, it can be considered that even if in steel exist solid solution C,
Do not occur yield point elongation YP-EL in stress-strain line chart yet.As a result, it is considered that the generation of elongation strain can be inhibited.
Based on above opinion, relationship further progress of the present inventor to C content and elongation at yield point YP-EL
Investigation.The C content (quality %) of cold-rolled steel sheet and the relationship of elongation at yield point YP-EL (%) are shown in Fig. 5.Furthermore the figure
5 be that investigation is controlled so as to obtained from the cold-rolled steel sheet of the microscopic structure mainly comprising ferrite and nodular cementite.
As shown in figure 5, elongation at yield point YP-EL is hastily reduced with the increase of C content.Specifically, when C contains
When amount is more than 0.150, elongation at yield point YP-EL becomes 0%.In addition, as described above, when C content is more than 0.150, accelerating
The yield strength YP in the direction L after ageing treatment reaches 360MPa or more.That is, if being gone back other than control microscopic structure etc.
C content is set as the intensity more than 0.150, being then able to satisfy among the characteristic being required as ironed can cold-rolled steel sheet and non-
St-St.
Specifically, being 10~40 DEG C/sec in the average heating speed that C content is more than 0.150, CAL, annealing temperature is again
Crystallization terminates temperature or more and ferrite single-phase region temperature (such as 650~715 DEG C), and being averaged for 500~400 DEG C of section is cold
But in the case that speed is 5~80 DEG C/sec, such the distinctive ferritic structure of present embodiment can be formed according to above-mentioned.Therefore,
If C content is more than 0.150, and implements the CAL of above-mentioned condition, then microscopic structure mainly includes ferrite and nodular cementite,
The average grain diameter of ferrite grain becomes 4.0 μm hereinafter, yield strength YP becomes 360MPa or more, and elongation at yield point YP-EL
Become 0%.
Furthermore as described above, the generation of elongation strain in order to prevent, previous steel plate implement BAF-OA etc..But
It is that previous steel plate is low as technical characteristic by C content.The steel plate of higher C content as being more than 0.150 in C content
In the case of, even if implementing BAF-OA etc., it is also difficult to fully reduce the solid solution C in steel, therefore substantially be difficult to YP-EL
Control is 0%.Steel plate of the present embodiment, even if C content is set as more than 0.150, by control manufacturing condition come shape
At above-mentioned ferritic structure, can also control YP-EL is 0%.
On the other hand, if C content is excessively high, cold-rolled steel sheet is exceedingly hardened, percentage of total elongation EL (%) decline, knot
Fruit, press formability decline.The present inventor investigates C content and the relationship of percentage of total elongation EL.Also, opinion is obtained
(iii)。
(iii) in cold-rolled steel sheet of the present embodiment, if C content is set as 0.260% hereinafter, and carrying out group
Control is knitted, then the percentage of total elongation EL in the direction L (rolling direction) after natrual ageing reaches 25% or more, is and previous ironed can
With the identical degree of the percentage of total elongation of cold-rolled steel sheet or more than it.Therefore, the excellent cold-rolled steel sheet of press formability can be obtained.
The C content (quality %) of cold-rolled steel sheet and the relationship of percentage of total elongation EL (%) are shown in Fig. 6.Furthermore the Fig. 6 is to adjust
It looks into obtained from the cold-rolled steel sheet for being controlled so as to the microscopic structure mainly comprising ferrite and nodular cementite.
As shown in fig. 6, relative to the increase of C content, always being stretched when C content is more than 0.150% and is 0.260% or less
Long rate EL constant.But when C content is more than 0.260%, percentage of total elongation EL hastily declines.Therefore, if C content
For 0.260% hereinafter, can then maintain excellent percentage of total elongation EL.Specifically, if C content be 0.260% hereinafter, if always stretch
Long rate EL reaches 25% or more.In addition, as described above, the lower limit of C content is set as super in order to meet intensity and non-St-St
Cross 0.150.That is, C content is set as more than 0.150% and is in ironed can cold-rolled steel sheet of the present embodiment
0.260% or less.
In turn, the present inventor is other than investigating the inhibition of the elongation strain as caused by above-mentioned C, also for
The inhibition of the elongation strain as caused by N is investigated.Moreover, having obtained opinion (iv).
(iv) if being set as C content more than 0.150% and for 0.260% hereinafter, and controlling B content and N content
For 0.4≤B/N≤2.5, then be able to suppress the generation of the elongation strain as caused by C and the elongation strain as caused by N generation this
The two.
It is more than the cold-rolled steel of 0.150% and the aluminum killed steel for 0.260% or less and B/N satisfaction 0.4~2.5 to C content
Plate implements CAL (continuous annealing).At this point, annealing temperature is set as described above, average heating speed is set as 10~40 DEG C/sec
Terminate temperature or more and ferrite single-phase region temperature (such as 650~715 DEG C) for recrystallization, by 500~400 DEG C thereafter
The average cooling rate in section is set as 5~80 DEG C/sec.In this case, in addition to the intensity of cold-rolled steel sheet, press formability and
Other than the non-St-St raising of C, B forms nitride in conjunction with N, therefore due to the age-hardening quilt of solid solution N
Inhibit, as a result, also inhibiting the generation of the elongation strain due to N.
Hereinafter, being described in detail to ironed can of the present embodiment with cold-rolled steel sheet.
[chemical composition]
Ironed can cold-rolled steel sheet of the present embodiment, as its chemical component, comprising basic element C, Sol.Al,
And B, surplus include Fe and impurity.
Furthermore " impurity ", which refers to, to be mixed into when industrially manufacturing steel from the ore, waste material or manufacturing environment etc. as raw material
Ingredient.Among these impurity, in order to fully play the effect of present embodiment, Si, Mn, P, S and N preferably such as with
It limits down.Additionally, it is preferred that the content of impurity is few, therefore does not need limitation lower limit value, the lower limit value of impurity may be
0%.
C: more than 0.150% and being 0.260% or less
Carbon (C) is dissolved to improve the intensity of steel.If the intensity of steel improves, cold-rolled steel sheet thickness can be subtracted
It is thin.If C content is more than 0.150, can make accelerated ag(e)ing treated the yield strength YP in the direction L reach 360MPa with
On.In turn, by implementing the CAL of aftermentioned condition, the average grain diameter of ferritic structure becomes 4.0 μm hereinafter, ferrite grain holds
Easily become the mangcorn comprising coarse grain and microfine.Treated as a result, it is possible to making accelerated ag(e)ing elongation at yield point
YP-EL becomes 0%.If C content be 0.15 hereinafter, if cannot obtain said effect.On the other hand, if C content is more than
0.260%, then the hardness of cold-rolled steel sheet becomes excessively high, as shown in fig. 6, total (after accelerated ag(e)ing processing) after natrual ageing saturation
Elongation EL decline.In this case, the press formability of cold-rolled steel sheet is lower.Therefore, C content is made to be more than 0.150% and be
0.260% or less.Furthermore C is austenite former.It is micro- in order to control in cold-rolled steel sheet of the present embodiment
Tissue, the preferably lower limit of C content are 0.153%, 0.155% or 0.160%.The preferred upper limit of C content is lower than 0.260%,
Further preferably 0.250%.Ferrite grain easily becomes mangcorn.
Si:0.50% or less
Silicon (Si) is the impurity inevitably contained.The coating adherence and the cold-rolled steel after tank processed that Si makes cold-rolled steel sheet
The coating adherence of plate declines.Therefore, Si content is limited to 0.50% or less.The preferred upper limit of Si content is lower than 0.50%.
Si content is preferably alap value.However, it is very difficult to industrially steadily make Si content 0%, therefore Si can be contained
The lower limit of amount is set as 0.0001%.
Mn:0.70% or less
Manganese (Mn) is the impurity inevitably contained.Mn makes cold-rolled steel sheet hardening, makes the percentage of total elongation of cold-rolled steel sheet
EL decline.Thus, press formability (drawing process) decline.In addition, Mn is austenite former, related in present embodiment
And cold-rolled steel sheet in, in order to control microscopic structure, do not added in steel.It is difficult in the case where Mn content is more than 0.70%
To obtain mechanical property specific to steel plate of the present embodiment.Therefore, Mn content is limited to 0.70% or less.Mn content
The preferred upper limit be lower than 0.70%.Mn content is preferably alap value.However, it is very difficult to industrially steadily contain Mn
Amount is 0%, therefore the lower limit of Mn content can be set as 0.0001%.
P:0.070% or less
Phosphorus (P) is the impurity inevitably contained.In general P improves the intensity of cold-rolled steel sheet.But if P contains
Measure excessively high, then press formability decline.Specifically, being configured to the decline of the resistance to secondary processing brittleness after ironed can.For deep-draw
For the ironed can that deep processing goes out, for example, brittleness is broken and impact in a low temperature of as -10 DEG C when falling sometimes
It splits, in addition, being strained sometimes through bending machining, the brittle fracture of pot sidewall end.Such fracture is known as secondary processing brittleness
Cracking.In the excessive situation of P content, it is easy to happen secondary processing brittleness cracking.Therefore, P content be limited to 0.070% with
Under.However, it is very difficult to industrially steadily make P content 0%, therefore the lower limit of P content can be set as 0.0001%.
S:0.05% or less
Sulphur (S) is the impurity inevitably contained.S makes steel plate surface layer when hot rolling that brittle cracking occur, and makes hot-rolled steel
Band generates side and splits.Therefore, S content is limited to 0.05% or less.S content is preferably alap value.However, it is very difficult in industry
On steadily make S content 0%, therefore the lower limit of S content can be set as 0.0001%.
Sol.Al:0.005~0.100%
Aluminium (Al) makes steel-deoxidizing.Al also improves the surface quality of slab in continuous casting.If Al content is too low, cannot obtain
To these effects.On the other hand, if Al content is excessively high, said effect saturation, manufacturing cost is got higher.Therefore, Al content is
0.005~0.100%.Al content in ironed can cold-rolled steel sheet of the present embodiment means Sol.Al's (dissolved aluminum)
Content.
N:0.0080% or less
Nitrogen (N) is the impurity inevitably contained.N is the element for making steel age-hardening, thus makes rushing for cold-rolled steel sheet
Pressing formation decline, makes elongation strain.In cold-rolled steel sheet of the present embodiment, by making in steel containing aftermentioned
B, and make N in conjunction with B and form nitride, to inhibit the age-hardening as caused by solid solution N.But if N content is excessively high,
Then it is easy to happen the age-hardening as caused by solid solution N.Therefore, N content is limited to 0.0080% or less.N content preferably to the greatest extent may be used
The low value of energy.However, it is very difficult to industrially steadily make N content 0%, therefore the lower limit of N content can be set as
0.0005%.
B:0.0005~0.02%
Boron (B) forms BN (boron nitride) in conjunction with N, to reduce solid solution N.When can inhibit as caused by solid solution N as a result,
Effect hardening.B also makes the texture disordering of cold-rolled steel sheet, makes r value (Lankford value) as plastic strain ratio close to 1.By
This, lug characteristic (the non-uniform degree of the tank height in tank circumferential direction occurred after drawing can shaping) improves.In addition, B is iron
Ferritic formation element is added in cold-rolled steel sheet of the present embodiment in order to control microscopic structure.If B content is low
In 0.0005%, then these effects cannot be obtained.On the other hand, if B content is more than 0.02%, above-mentioned effect saturation.
Therefore, B content is 0.0005~0.02%.The lower limit of B content is preferably 0.0010% or 0.0015%.
In turn, in cold-rolled steel sheet of the present embodiment, the content of B and N is dependently of each other provided.As it is above-mentioned that
Sample, when being dissolved N excess in steel, age-hardening can occur for steel.Thus, make to form BN containing B in steel.On the other hand, when
When being dissolved B excess in steel, cold-rolled steel sheet hardening, lug decline.It is then desired to dependently of each other provide the content of B and N.
Specifically, the B content and N content in chemical component need to meet 0.4≤B/N≤2.5 in terms of quality %.In the content of B and N
When meeting above-mentioned condition, it can inhibit highly desirablely while inhibiting the decline of the above-mentioned characteristic as caused by solid solution B by being dissolved
The generation of elongation strain caused by N.The lower limit of the value of B/N is preferably 0.8.
In cold-rolled steel sheet of the present embodiment, preferably other than limiting above-mentioned impurity, also limitation niobium (Nb),
Titanium (Ti), copper (Cu), nickel (Ni), chromium (Cr) and tin (Sn).Specifically, in order to fully play the effect of present embodiment
Fruit is preferably limited to Nb:0.003% or less, Ti:0.003% or less, Cu:0.5% or less, Ni:0.5% or less, Cr:0.3%
Below and Sn:0.05% or less.Especially Ti impacts the formation of microscopic structure due to forming TiN, preferably
It is limited as described above.The content of these impurity is preferably alap value.However, it is very difficult to industrially steadily make
The content of these impurity is 0%, therefore the lower limit of the content of these impurity can be set to 0.0001%.
Above-mentioned chemical component is measured using the general analysis method of steel.For example, above-mentioned chemical component makes
It is measured i.e. with ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry)
It can.Specifically, producing granular sample by the position in the center from steel plate, and based on pre-made calibration curve (school
Directrix) under conditions of carry out chemical analysis just can determine.But C and S is measured i.e. using burning-infrared absorption
Can, N is measured using inert gas fusion-thermal conductivity method.
[microscopic structure]
Cold-rolled steel sheet of the present embodiment mainly includes that average grain diameter (average diameter) is as its microscopic structure
2.7~4.0 μm of ferrite and nodular cementite.In addition, above-mentioned BN is nano-precipitation, therefore the low range the case where
Under can not observe, but as microscopic structure, may include the BN.In cold-rolled steel sheet of the present embodiment, pass through
Other than controlling into above-mentioned chemical component, also control can obtain high-intensitive, press formability at above-mentioned microscopic structure
Excellent, non-St-St also excellent cold-rolled steel sheet.
Above-mentioned ferrite, nodular cementite and BN preferably adds up to 95~100 area % in microscopic structure.
That is, pearlite, martensite, retained austenite etc. as the tissue other than ferrite, nodular cementite and BN, are preferably limited
It is lower than 5 area % to be total.Alternatively, it is preferred that not containing.Total area of tissue other than ferrite, nodular cementite and BN
Divide rate, preferably alap value.Therefore, cold-rolled steel sheet of the present embodiment, it is further excellent as its microscopic structure
Choosing is only made of ferrite, nodular cementite and BN.
In addition, as described above, in cold-rolled steel sheet of the present embodiment, there are ferrite grains to become comprising coarse
The tendency of grain and the mangcorn of microfine.Although being difficult to quantitatively provide the mangcorn, it is considered that the microscopic structure is to this
Mechanical property specific to the steel plate that embodiment is related to brings influence.
Furthermore in cold-rolled steel sheet of the present embodiment, define as described below each contained in microscopic structure
Constitute phase.Ferrite and ferrite grain are defined as taking with the body-centered cubic structure (bcc) and crystal due to diffusion transformation
It is 0 ° of region more than or lower than 15 ° to differential seat angle.Martensite and martensite grain are defined as having due to diffusionless transformation
Body-centered cubic structure (bcc) or B.C.T. structure (bct) and crystal orientation differential seat angle be 0 ° of area more than or lower than 15 °
Domain.Cementite is defined as the compound (Fe of the Fe with orthorhombic structure and C3C).Pearlite and pearlite block (pearlite
Block it) is defined as with the ferritic crystal orientation in the lamellar tissue and the pearlite being made of ferrite and cementite
Differential seat angle is 0 ° of region more than or lower than 9 °.Nodular cementite is defined as the cementite being not included in pearlite block.BN is fixed
Justice is the compound of B and N with structure of hexagonal crystal or cubic structure.
Above-mentioned microscopic structure, using the section L (section parallel with rolling direction of optical microphotograph sem observation cold-rolled steel sheet
Face).In addition, ferritic average grain diameter is found out based on the patterning method of JIS G0551 (2013).In addition, each structure
Line Integral rate at phase etc. is found out by carrying out image analysis to microstructure picture.
[mechanical property]
The plate thickness of cold-rolled steel sheet of the present embodiment is 0.15~0.50mm, and cold-rolled steel sheet is implemented at 100 DEG C
1 hour ageing treatment (accelerated ag(e)ing processing) carries out tension test afterwards, by the yield strength obtained by the tension test by
Units MPa is denoted as YP, and percentage of total elongation is denoted as EL by unit %, and elongation at yield point is denoted as YP-EL by unit %, and yield ratio is pressed
When unit % is denoted as YR, YP is 360~430MPa, and EL is 25~32%, YP-EL 0%, and YR is 80~87%.
Here, tension test, using the parallel portion tensile sample parallel with the direction L (rolling direction), room temperature (25 DEG C),
Implemented in atmosphere according to JIS Z2241 (2011).
YP:360~430MPa
If yield strength YP is 360MPa or more, even if cold-rolled steel sheet is thinning (thickness is thinned), can also obtain
The ironed can excellent to resistance to interior external pressure strength.On the other hand, the upper limit of yield strength YP is not specially limited.But work as surrender
When intensity YP is excessively high, it is difficult to it is stamping, therefore yield strength YP can be set as 430MPa or less.Furthermore in this embodiment party
The cold-rolled steel sheet that formula is related to, as described above using do not show specific yield point as technical characteristic, therefore yield strength YP
Mean 0.2% endurance.
EL:25~32%
If percentage of total elongation EL is 25% or more, the press formability as ironed can cold-rolled steel sheet can be satisfied
(drawing process).On the other hand, the upper limit about percentage of total elongation EL, value are the bigger the better, therefore are not specially limited.But
It is difficult to that percentage of total elongation EL is industrially steadily made to be more than 32%, therefore the upper limit of percentage of total elongation EL can be set as 32%, more
It is preferably set to 30%.Furthermore percentage of total elongation EL refers to the sum of elastic extension and permanent elongation.
Furthermore as described above, preferably cold-rolled steel sheet is thinning.Thus, for cold-rolled steel sheet of the present embodiment
For, plate thickness is set as 0.15~0.50mm.But in the range of the plate thickness, plate thickness is thicker, the value of percentage of total elongation EL is got over
Greatly.Therefore, in the case where the raising of press formability to be made (drawing process) is preferential, plate thickness can be set as be more than
0.20mm and for 0.50mm or less, percentage of total elongation EL is set as 27~32%.
YP-EL:0%
If elongation at yield point YP-EL is 0%, it is able to suppress and is hindered after rigid surrender in the deformation smaller than yield point
The stead deformation carried out under power, therefore it is able to suppress the generation of elongation strain.Furthermore in cold-rolled steel sheet of the present embodiment
In, elongation at yield point YP-EL means for 0%: without carrying out in the change smaller than yield point (0.2% endurance) after rigid surrender
Deformation (strain) under form drag (stress).That is, in cold-rolled steel sheet of the present embodiment, elongation at yield point YP-EL
Mean for 0%: there is no yield point declines, and just load-deformation curve is just shown (after just having reached 0.2% endurance) after surrender
Processing hardening out.
YR:80~87%
If yield ratio YR is 80% or more, mean that relative to tensile strength TS, yield strength YP be sufficiently high
Value.Thus, it is possible to which cold-rolled steel sheet is thinning (thickness is thinned), the excellent ironed can of resistance to interior external pressure strength can be obtained.That is,
The big trunk top of processing dependent variable when the small tank bottom and drawing process of processing dependent variable when to drawing process is compared
When, in ironed can after forming, tank bottom and the intensity difference on trunk top become smaller, and can obtain the uniform drawing of mechanical quality
Tank.On the other hand, the upper limit of yield ratio YR is not specially limited.But when yield ratio YR is excessively high, it is difficult to it is stamping, because
Yield ratio YR can be set as 87% or less by this.Furthermore the yield strength YP that yield ratio YR means that unit is MPa is divided by unit
The tensile strength TS of MPa and the percentage being worth.
[coating]
Cold-rolled steel sheet of the present embodiment, can on the surface of cold-rolled steel sheet (in plate face) configured with plating Ni layers,
Ni diffusion coating, Sn layers of plating and sheet iron of wuxi (TFS:tin free steel) coating are (by Cr layers of metal and Cr aqua oxidation
The coating of this two layers of nitride layer composition) among at least one party.By configuring above-mentioned coating, surface in the plate face of cold-rolled steel sheet
The raisings such as appearance improves, and corrosion resistance, chemical resistance, proof stress are anti-thread breakage.
Hereinafter, being described in detail to the manufacturing method of ironed can of the present embodiment cold-rolled steel sheet.
An example of the manufacturing method of ironed can of the present embodiment cold-rolled steel sheet is illustrated.Present embodiment
The manufacturing method for the ironed can cold-rolled steel sheet being related to, has: obtaining the process (steel process processed) of slab, obtains hot rolled steel plate
Process (hot-rolled process), obtains the process (lehr attendant of annealed sheet steel at the process (once cold rolling process) for obtaining once cold rolling steel plate
Sequence) and obtain the process (skin-pass process) of skin-pass steel plate.
[steel process processed]
Following molten steel is manufactured in steel process processed, contains C: more than 0.150% and being 0.260% or less, Sol.Al:
0.005~0.100%, B:0.0005~0.02%, Si:0.50% or less, Mn:0.70% or less, P:0.070% or less, S:
0.05% or less, N:0.0080% or less, Nb:0.003% or less, Ti:0.003% are hereinafter, surplus includes Fe and impurity, chemistry
Boron content and nitrogen content in ingredient satisfaction 0.4≤B/N≤2.5 in terms of quality %.Slab (plate is manufactured by the molten steel produced
Base).For example, carrying out block using casting methods such as common continuous metal cast process, ingot casting method, sheet billet castings.Furthermore
In the case where continuous casting, steel can be once cooled to low temperature (such as room temperature), after being reheated, which is subjected to hot rolling,
It can be by steel (block) continuously hot rolling after rigid casting.
[hot-rolled process]
In hot-rolled process, the slab after steel process processed is heated to 1000 DEG C or more (such as 1000~1280 DEG C),
Finish rolling is carried out at 840~950 DEG C, in smart roller repairing, is batched at 500~720 DEG C, to manufacture hot rolled steel plate.
Cementite (Fe when coiling temperature CT is more than 720 DEG C, in hot rolled steel plate3C) in blocky ground coarsening.In the feelings
Under condition, the percentage of total elongation EL of cold-rolled steel sheet can be reduced.If coiling temperature CT is lower than 500 DEG C, the cementite in hot rolled steel plate
Become the tissue of hard.Thus, the percentage of total elongation EL of cold-rolled steel sheet can be reduced.Accordingly, it is preferred that coiling temperature CT be 500~
720℃.Furthermore in order to ideally control microscopic structure, the lower limit of coiling temperature CT is more preferably 600 DEG C.
[once cold rolling process]
In once cold rolling process, to the hot rolled steel plate after hot-rolled process implement accumulative reduction ratio be more than 80% it is primary cold
It rolls, to manufacture the once cold rolling steel plate that plate thickness is 0.15~0.50mm.
In once cold rolling, makes cold rolling rate variation to study the optimal cold rolling rate of ironed can cold-rolled steel sheet, set cold
Roll rate so that steel plate intra-face anisotropy Δ r substantially 0 (specifically, Δ r be+0.15~-0.08 range).Separately
Outside, setting cold rolling rate is adapted to provide for make it once cold rolling steel plate to the microscopic structure (worked structure) in rear process.?
In once cold rolling, accumulative reduction ratio is set as more than 80%.The lower limit of accumulative reduction ratio is preferably 84%.On the other hand, add up
The upper limit of reduction ratio is not specially limited.But due to being difficult to that accumulative reduction ratio is industrially steadily made to be more than 90%,
The upper limit of accumulative reduction ratio can be set as 90%.Furthermore accumulative reduction ratio is according to before the first passage in once cold rolling
The calculated reduction ratio of difference of outlet plate thickness after entrance plate thickness and final passage.
The plate thickness of once cold rolling steel plate is preferably 0.151~0.526mm.If plate thickness is more than 0.526mm, it is difficult to obtain
Excellent lug.If plate thickness is lower than 0.151mm, the plate thickness of hot rolled steel plate must be made relatively thin, it in this case cannot be true
Protect finishing temperature when above-mentioned hot rolling.Therefore, the plate thickness of once cold rolling steel plate is preferably 0.151~0.526mm.
[annealing operation (CAL process)]
In annealing operation, implement following continuous annealings to manufacture annealed sheet steel: will be primary cold after once cold rolling process
Rolled steel plate is heated up with 10~40 DEG C/sec of average heating speed, terminates temperature or more and ferrite single-phase region temperature in recrystallization
Soaking is carried out under (such as 650~715 DEG C), thereafter, the average cooling rate in 500~400 DEG C of sections is 5~80 DEG C/sec
Under conditions of cooled down.
If in the temperature-rise period of annealing operation, by once cold rolling steel plate with average heating speed HR:10~40 DEG C/sec
Heating, then can ideally control microscopic structure.In the temperature-rise period of annealing operation, the worked structure of once cold rolling steel plate is carried out
It replys, recrystallization nucleus is generated in worked structure.By the way that once cold rolling steel plate heats up under the above conditions, can ideally control
The recrystallization process of worked structure, therefore microscopic structure specific to present embodiment can be desirably resulted in.Furthermore further
It is preferred that in the temperature-rise period, make 10~20 DEG C/sec of the average heating speed in 500~700 DEG C of section and by once cold rolling
Steel plate heating.
Annealing temperature (soaking temperature) ST, which is set as recrystallization, to be terminated temperature or more and is ferrite single-phase region temperature.?
In the case where the above-mentioned chemical component of drawing steel plate for tanks of the present embodiment, 650~715 DEG C of temperature range is equivalent to
Recrystallization terminates temperature or more and ferrite single-phase region temperature.By carrying out soaking within this temperature range, can ideally control
Microscopic structure processed.Furthermore the upper limit of annealing temperature ST is preferably 710 DEG C or 705 DEG C.
When annealing temperature ST is more than ferrite single-phase region temperature (such as more than 715 DEG C), just become in ferrite and
Annealing at a temperature of the dual phase region of austenite, therefore will form pearlite when cooling after soaking.Thus, it cannot obtain
The microscopic structure stated.In the case where the microscopic structure comprising pearlite, yield ratio YR decline.Moreover, ferritic average grain
Diameter becomes larger than 4.0 μm.If annealing temperature ST is 650~715 DEG C, microscopic structure can be ideally controlled.In addition, annealing
Retention time under temperature ST is set as 15~30 seconds.
It is after carrying out soaking at above-mentioned annealing temperature ST, steel plate is cooling.At this point, making being averaged for 500~400 DEG C of section
Cooling velocity CR is 5~80 DEG C/sec.If average cooling rate CR is more than 80 DEG C/sec, being dissolved C amount becomes excessively high.In the feelings
Under condition, treated that elongation at yield point YP-EL becomes larger than 0% for accelerated ag(e)ing.On the other hand, if average cooling rate
CR is lower than 5 DEG C/sec, then being dissolved C amount becomes too low.In this case, yield strength YP gets lower than 360MPa.If 500~
The average cooling rate CR in 400 DEG C of section is 5~80 DEG C/sec, then can ensure that solid solution C amount is 5~50ppm or so.Thus, add
Yield strength YP after fast ageing treatment reaches 360MPa or more, and elongation at yield point YP-EL becomes 0%.Moreover, can obtain
To excellent percentage of total elongation EL and high yield ratio YR.In addition, if the average cooling rate CR in 500~400 DEG C of section is 5
~80 DEG C/sec, then it can ideally control microscopic structure.
[the Wetted constructures process (BAF-OA process) realized by box annealing]
In the manufacturing method of cold-rolled steel sheet of the present embodiment, do not implement BAF-OA.As described above, even if not
Implement BAF-OA, the cold-rolled steel sheet of present embodiment also has high intensity, and press formability is excellent, and non-St-St is also excellent.
If implementing BAF-OA in the manufacturing method of cold-rolled steel sheet of the present embodiment, the solid solution C in steel is reduced, surrender
Intensity YP gets lower than 360MPa.Therefore, in the manufacturing method of cold-rolled steel sheet of the present embodiment, do not implement BAF-
OA.In the present embodiment, due to not implementing BAF-OA, the productivity of ironed can cold-rolled steel sheet is significantly improved.
[skin-pass process]
In skin-pass process, will not have after annealing operation the annealed sheet steel for implementing Wetted constructures with 0.5~
5.0% accumulative reduction ratio carries out skin-pass (skin pass rolling), to manufacture skin-pass steel plate.If reduction ratio is lower than
0.5%, then in accelerated ag(e)ing treated steel plate, elongation at yield point YP-EL becomes more than 0% sometimes.If reduction ratio
More than 5.0%, then percentage of total elongation EL gets lower than 25%, press formability decline.If reduction ratio is 0.5~5.0%, directly
Excellent non-St-St and press formability can be also obtained after the age-hardening occurred until the processing such as drawing.It is quenched to roll
The plate thickness of skin-pass steel plate after process processed becomes 0.15~0.50mm.
[plating process]
In the manufacturing method of cold-rolled steel sheet of the present embodiment, it can also be rolled after skin-pass process quenched
Implement (in plate face) among plating Ni processing, Ni diffusion plating, plating Sn processing and TFS plating on the surface of steel plate processed at least
A kind of processing.In this case, Sn layers and TFS Ni layers of plating, Ni diffusion coating, plating platings are formed in the plate face of skin-pass steel plate
At least one party among layer (by Cr layers of metal and this two layers coating constituted of Cr aqua oxidation nitride layer).Furthermore Ni diffusion coating
It is to be formed and implementing diffusion heat treatments to the steel plate for implementing plating Ni processing.
By controlling each manufacturing condition in above-mentioned each process fine and closely and compound, present embodiment can be obtained and be related to
Cold-rolled steel sheet specific to microscopic structure.Specifically, only by by the hot rolled steel plate after each process control hot-rolled process
Micro- group of annealed sheet steel after the microstructure annealing operation of once cold rolling steel plate after microstructure once cold rolling process
Knit and skin-pass process after skin-pass steel plate microscopic structure, can obtain micro- specific to present embodiment
Tissue.As a result, it is possible to obtain, high-intensitive, press formability is excellent, non-St-St also excellent ironed can cold-rolled steel sheet.
Embodiment 1
Then, effect more specific by embodiment, explaining a kind of technical solution of the invention in detail, but in embodiment
Condition be the condition example used to confirm exploitativeness and effect of the invention, the present invention is not by a condition
Example limits.As long as the present invention can use various conditions not departing from the gist of the invention, being able to achieve the purpose of the present invention.
As steel process processed, the slab of steel grade A~M has been manufactured.
As hot-rolled process, by these heating of plate blank to 1200 DEG C, implement hot rolling, manufactures the hot rolling that plate thickness is 2.1mm
Steel plate.The finishing temperature of hot rolling is 925 DEG C.The coiling temperature CT of hot rolled steel plate is as shown in table 1.
Once cold rolling is implemented after hot rolled steel plate pickling as once cold rolling process.Test number 1~19, manufacture
The once cold rolling steel plate of plate thickness 0.25mm.Number 20 is tested, the once cold rolling steel plate of plate thickness 0.45mm has been manufactured.Once cold rolling
Accumulative reduction ratio is as shown in table 1.
As annealing operation, CAL (continuous annealing) is implemented to the steel plate after once cold rolling process.Average heating speed
HR, annealing temperature ST, the average cooling rate CR in 500~400 DEG C of section are as shown in table 1.At annealing temperature ST, by steel plate
It carries out soaking 25 seconds.After carrying out soaking, gas cooling is implemented using nitrogen.At this point, and the cooling without 2 stages
(not keeping steel plate at intermediate temperatures), but steel plate is cooled to 50 DEG C from annealing temperature ST.Under gas cooling, from
500 DEG C of average cooling rate CR until 400 DEG C are as shown in table 1, from 400 DEG C of average cooling rates until 50 DEG C be 25
DEG C/sec.
The steel plate for testing number 1 further implements the BAF-OA (overaging carried out by box annealing after CAL
Processing).In BAF-OA, after steel plate is carried out soaking 5 hours at 450 DEG C, spend carried out slow cooling within 72 hours.Furthermore it tries
The steel plate tested other than number 1 does not implement BAF-OA.
As skin-pass process, skin-pass is implemented to the steel plate after annealing operation.Reduction ratio in skin-pass
It is 1.8%.
As plating process, plating Ni processing is implemented to the steel plate for testing number 8 shown in table 1.Specifically, quenched
After rolling process, Ni layers of plating is formd on the surface of steel plate and the back side using galvanoplastic.The film thickness of Ni layers of the plating on surface and the back side
It is 2 μm.The steel plate of the test number 8 becomes the cold-rolled steel sheet that two sides has Ni layers of plating.
About the cold-rolled steel sheet produced as described above, the measurement result of chemical component is shown in Table 2, microscopic structure
The measurement result of observation result and mechanical property is shown in Table 3.
It is observed on the section L of the cold-rolled steel sheet produced using optical microscopy about microscopic structure.Group
The sample for knitting observation is produced from the central portion of the width direction of the cold-rolled steel sheet produced.About microstructure picture,
Have taken the position ground and between 1/4 thickness of the thickness direction in the section L of sample that corroded through nital.
Using microstructure picture, ferritic average grain diameter is found out using the patterning method of JIS G0551 (2013).
In table 2, " F+C " indicates that microscopic structure master includes ferrite and nodular cementite." F+P " indicates microscopic structure master
It to include ferrite and pearlite.Non-recrystallization tissue is observed in " ×× " expression.The case where observing non-recrystallization tissue
Under, do not measure ferrite average grain diameter (because can not measure).
Mechanical property carries out tension test using the cold-rolled steel sheet produced to measure.By the cold-rolled steel of each test number
Plate has made JIS5 tensile sample.The parallel portion of tensile sample is parallel with the direction L (rolling direction) of cold-rolled steel sheet.To production
Tensile sample out implements accelerated ag(e)ing processing.Specifically, each tensile sample is implemented at 100 DEG C 1 hour when
Effect processing.
According to JIS Z2241 (2011), accelerated ag(e)ing treated tensile sample is implemented in room temperature (25 DEG C), atmosphere
Tension test has found out yield strength YP, tensile strength TS, percentage of total elongation EL, elongation at yield point YP-EL, yield ratio YR.
As example of the present invention test number 5,7,8,11,13 and 15 cold-rolled steel sheet, manufacturing condition, chemical component,
Microstructure mechanical property all meets the scope of the present invention.As a result, these cold-rolled steel sheets have high intensity, press formability
Excellent, non-St-St is also excellent.
On the other hand, as 1~4,6,9,10,12,14,16~20 cold-rolled steel sheet of comparative example, manufacturing condition, chemistry
A certain in ingredient, microstructure mechanical property is unsatisfactory for the scope of the present invention.As a result, these cold-rolled steel sheets cannot be simultaneously
Realize intensity, press formability and non-St-St.
Testing number 1 is the previous example that BAF-OA is implemented after CAL, and C content is too low.Moreover, coiling temperature CT mistake
It is high.Moreover, the annealing temperature ST of CAL is excessively high, it is 2 alpha region temperature.Thus, microscopic structure is made of ferrite and pearlite,
Ferritic average grain diameter is more than 4.0 μm, and yield strength YP is lower than 360MPa.Moreover, yield ratio YR is lower than 80%.
Test number 2~4 and 18, although manufacturing condition be it is appropriate, C content is too low.Thus, it is ferritic flat
Equal partial size is more than 4.0 μm, and yield strength YP is lower than 360MPa.Moreover, elongation at yield point YP-EL is higher than 0%, drawn
Stretching strain.
Test number 6 and 14, although chemical composition be it is appropriate, the annealing temperature ST in CAL is excessively high, be 2 phases
Regional temperature.Thus, microscopic structure is made of ferrite and pearlite, and ferritic average grain diameter is more than 4.0 μm.Thus, always
Elongation EL and/or yield ratio YR are low, and press formability is low.Moreover, the yield strength YP of test number 6 is lower than 360MPa.
Number 9 is tested, although chemical composition is appropriate, the average cooling in 500~400 DEG C of section in CAL
Speed CR is excessively slow.Thus, yield strength YP is lower than 360MPa, and yield ratio YR is lower than 80%.May be considered cooling velocity it is excessively slow,
It is dissolved the too low reason of C amount.
Number 10 is tested, although chemical composition is appropriate, the average cooling in 500~400 DEG C of section in CAL
Speed CR is too fast.Thus, elongation at yield point YP-EL is higher than 0%.Moreover, percentage of total elongation EL is lower than 25%.
Test number 12, although chemical composition be it is appropriate, the annealing temperature ST in CAL is too low.Thus, aobvious
Non-recrystallization tissue has been remained in a part of micro-assembly robot.As a result, percentage of total elongation EL is lower, it is lower than 25%, press formability
It is low.
The C content for testing number 16,17 and 19 is excessively high.Thus, percentage of total elongation EL is too low, stamping lower than 25%
Property is low.
Test number 20, although chemical composition be it is appropriate, the accumulative reduction ratio in once cold rolling is too low.Cause
And ferritic average grain diameter is more than 4.0 μm, yield strength YP is lower than 360MPa.Moreover, elongation at yield point YP-EL is higher than
0%, elongation strain has occurred.
Industrial availability
Above-mentioned technical proposal according to the present invention, can provide without implementing BAF-OA high-intensitive, press formability is excellent,
Non- St-St also excellent drawing steel plate for tanks.The press formability of the cold-rolled steel sheet is excellent, is able to suppress elongation strain
Occur, can be realized thickness and be thinned.Thus, industrial availability is very high.
Description of symbols
10: ferrite
20: nodular cementite
Claims (5)
1. a kind of drawing steel plate for tanks, which is characterized in that
The steel plate is cold-rolled steel sheet, as the chemical component of the steel plate, is contained in terms of quality %
C: more than 0.150% and for 0.260% or less,
Sol.Al:0.005~0.100%,
B:0.0005~0.02%,
Si:0.50% or less,
Mn:0.70% or less,
P:0.070% or less,
S:0.05% or less,
N:0.0080% or less,
Nb:0.003% or less,
Ti:0.003% hereinafter,
Surplus includes Fe and impurity,
Boron content and nitrogen content in the chemical component satisfaction 0.4≤B/N≤2.5 in terms of quality %,
As the microscopic structure of the steel plate, the ferrite and nodular cementite that are 2.7~4.0 μm comprising average grain diameter,
The draw direction stretching parallel with rolling direction is carried out after the steel plate to be implemented to 1 hour ageing treatment at 100 DEG C
The yield strength obtained by the tension test is denoted as YP, percentage of total elongation by units MPa and is denoted as EL, surrender by unit % by test
When point elongation is denoted as YP-EL by unit %, yield ratio is denoted as YR by unit %,
The YP is 360~430MPa,
The EL is 25~32%,
The YP-EL is 0%,
The YR is 80~87%.
2. drawing steel plate for tanks according to claim 1, which is characterized in that
The EL is 27~32%.
3. drawing steel plate for tanks according to claim 1 or 2, which is characterized in that
On the surface of the steel plate configured with plating Ni layer, Ni diffusion coating, plating Sn layers and TFS coating at least one of plate
Layer.
4. a kind of manufacturing method of drawing steel plate for tanks, is the method for drawing steel plate for tanks described in manufacturing claims 1 or 2,
It is characterized in that, having:
Obtain the steel process processed of the slab with the chemical component；
The slab is heated to 1000 DEG C or more by hot-rolled process, the process, finish rolling is carried out at 840~950 DEG C, after finish rolling
It is cooling, batch at 500~720 DEG C obtaining hot rolled steel plate；
Once cold rolling process, the process implement the once cold rolling that accumulative reduction ratio is more than 80% to the hot rolled steel plate, thus
To once cold rolling steel plate；
Annealing operation, the process implement continuous annealing to obtain annealed sheet steel, and the continuous annealing is by the once cold rolling
Steel plate is heated up with 10~40 DEG C/sec of average heating speed, soaking is carried out within the temperature range of 650~715 DEG C, thereafter, 500
With 5~80 DEG C/sec of cooling annealing of average cooling rate in~400 DEG C of temperature range；With
Skin-pass process, the process will do not have after the annealing operation implement Wetted constructures the annealed sheet steel with
0.5~5.0% accumulative reduction ratio carries out skin-pass, to obtain skin-pass steel plate.
5. the manufacturing method of drawing steel plate for tanks according to claim 4, which is characterized in that
Be also equipped with plating process, the process after the skin-pass process to the skin-pass steel plate implement plating Ni processing,
Ni spread plating, plating Sn processing and TFS plating at least one of processing.
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| Application Number | Priority Date | Filing Date | Title |
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| JP2014-213239 | 2014-10-17 | ||
| JP2014213239 | 2014-10-17 | ||
| PCT/JP2015/079313 WO2016060248A1 (en) | 2014-10-17 | 2015-10-16 | Steel sheet for drawn can, and method for manufacturing same |
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| CN106795609A CN106795609A (en) | 2017-05-31 |
| CN106795609B true CN106795609B (en) | 2018-12-04 |
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| JP (1) | JP5930144B1 (en) |
| CN (1) | CN106795609B (en) |
| TW (1) | TWI560280B (en) |
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| CN109423577B (en) * | 2017-08-30 | 2021-01-12 | 宝山钢铁股份有限公司 | High-strength multi-phase steel tinning raw plate and manufacturing method thereof |
| MX2021005983A (en) * | 2018-11-21 | 2021-07-06 | Jfe Steel Corp | Steel sheet for cans and method for manufacturing same. |
| EP3901300A4 (en) * | 2018-12-20 | 2022-04-27 | JFE Steel Corporation | Steel plate for can and method for producing same |
| JP7368692B2 (en) * | 2019-03-29 | 2023-10-25 | 日本製鉄株式会社 | Manufacturing method of medium carbon steel plate |
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| CN1429924A (en) * | 1998-05-29 | 2003-07-16 | 东洋钢钣股份有限公司 | Resin cladded steel plate for thin wall-type tensile can and its used steel plate |
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| JP3931455B2 (en) * | 1998-11-25 | 2007-06-13 | Ｊｆｅスチール株式会社 | Steel plate for can and manufacturing method thereof |
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| JP5355905B2 (en) * | 2007-04-10 | 2013-11-27 | 新日鐵住金ステンレス株式会社 | Structural member for automobile, two-wheeled vehicle or railway vehicle having excellent shock absorption characteristics, shape freezing property and flange section cutting ability, and method for producing the same |
| JP4235247B1 (en) * | 2007-09-10 | 2009-03-11 | 新日本製鐵株式会社 | High-strength steel sheet for can manufacturing and its manufacturing method |
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2015
- 2015-10-16 CN CN201580055679.7A patent/CN106795609B/en active Active
- 2015-10-16 TW TW104134061A patent/TWI560280B/en not_active IP Right Cessation
- 2015-10-16 JP JP2016507711A patent/JP5930144B1/en active Active
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| CN1429924A (en) * | 1998-05-29 | 2003-07-16 | 东洋钢钣股份有限公司 | Resin cladded steel plate for thin wall-type tensile can and its used steel plate |
| JP2004225132A (en) * | 2003-01-24 | 2004-08-12 | Nippon Steel Corp | High strength cold rolled steel sheet and plated steel sheet having excellent deep drawability, steel tube having excellent workability, and production method therefor |
| CN1667151A (en) * | 2004-03-10 | 2005-09-14 | 杰富意钢铁株式会社 | High carbon hot-rolled steel sheet and method for manufacturing the same |
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| JP2014043631A (en) * | 2012-08-28 | 2014-03-13 | Nippon Steel & Sumitomo Metal | Method of manufacturing fine grain steel sheet |
| CN107148488A (en) * | 2015-01-07 | 2017-09-08 | Posco公司 | Superhigh intensity coated steel sheet and its manufacture method that tensile strength is more than 1300Mpa |
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| JP5930144B1 (en) | 2016-06-08 |
| WO2016060248A1 (en) | 2016-04-21 |
| TW201623653A (en) | 2016-07-01 |
| CN106795609A (en) | 2017-05-31 |
| TWI560280B (en) | 2016-12-01 |
| JPWO2016060248A1 (en) | 2017-04-27 |
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