CN102712983B - Cold-rolled steel plate and method for producing same - Google Patents
Cold-rolled steel plate and method for producing same Download PDFInfo
- Publication number
- CN102712983B CN102712983B CN201180006238.XA CN201180006238A CN102712983B CN 102712983 B CN102712983 B CN 102712983B CN 201180006238 A CN201180006238 A CN 201180006238A CN 102712983 B CN102712983 B CN 102712983B
- Authority
- CN
- China
- Prior art keywords
- rolling
- value
- cold
- elongation
- average
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
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
- 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
-
- 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
- C21D8/0273—Final recrystallisation annealing
-
- 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
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Sheet Steel (AREA)
Abstract
Provided is a cold-rolled steel plate having excellent moldability and shape retention, and outstanding production stability using actual machinery. Also provided is a method for producing same. The composition contains 0.0010 to 0.0030% C, no more than 0.05% C, 0.1 to 0.3% Mn, no more than 0.05% P, no more than 0.02% S, 0.02 to 0.10% Al, no more than 0.005% N, 0.010 to 0.030% Nb, and 0.0010 =<B-11/14N=<0.0050% B, with the remainder made up of iron and inevitable impurities. The average total elongation (Elm) is at least 42%, and average r value (rm) is 1.2 to 1.6. By maintaining post cold-rolling annealing for 30 to 200 sec. at a holding temperature of (820+Nb/15+B-CR) to 860 DEG C according to compression rate CR(%), Nb content (mass ppm) and B content (mass ppm), it is possible to manufacture the cold-rolled steel plate using actual machinery in a stable manner, without pinpoint control of the holding temperature.
Description
Technical field
The present invention relates to most suitable as the backlight chassis of large-scale LCD TV etc. make large flat shape parts member, plasticity, shape freezing and real machine manufacture cold-rolled steel sheet and the manufacture method thereof of excellent in stability.
Background technology
In slim liquid crystal TV and OA equipment etc., the flat-shaped part that processes shape that use is main body by crooked, expansion forming mostly.For the member using (material), from viewpoints such as the designability of product and slimmings, component shape is being required to, on the basis of degree of finish, in most cases also require Flatness in these parts.Yet, when the platen surface of member (material) is carried out to bending, expansion forming, there is the deteriorated tendency of Flatness.This Flatness is deteriorated is that member (material) is carried out when stamping, because of the poor phenomenon producing of shape freezing of member (material), therefore, the steel plate as member (material) being required to processibility and shape freezing simultaneously.
In addition, as the major cause that makes Flatness variation, the crest line warpage producing while being well known that bending machining.It is said as one of them, the warpage that produces at crooked end can reduce by reducing the r value of material, established the technology of material being given to low r value, low yield strength at present.
For example, in patent documentation 1, disclosing exploitation, to have yield strength be that the r value of 150MPa, rolling direction is the technology of the cold-rolled steel sheet of 0.67 (the r value of rolling right angle orientation is 1.45).
Parallel with plate face { 100} face and { ratio of 111} face is the good automobile ferritic series steel sheet of more than 1.0 shape freezings is disclosed in patent documentation 2.
In patent documentation 3, in order to obtain the good ferritic series steel sheet of shape freezing, following scheme is disclosed: control { 100} < 011 > ~ { intensity of 223}<110> orientation group and { 112} < 110 >, { 554} < 225 >, { 111} < 112 >, { the intensity of each orientation of 111} < 110 >, make rolling direction r value and with the r value of the rectangular direction of rolling direction at least one be below 0.7.
Prior art document
Patent documentation
Patent documentation 1: No. 3532138 communique of Japanese Patent
Patent documentation 2: TOHKEMY 2008-255491 communique
Patent documentation 3: TOHKEMY 2003-55739 communique
Summary of the invention
Invent problem to be solved
But, in the technology of recording in patent documentation 1 and 3, by employing, there is { 100} < 011 > ~ { crystal grain of 223} < 110 > orientations, can reduce the r value of rolling direction and rolling right angle orientation, but can increase the r value of 45 ° of directions of rolling, therefore, there are a large amount of { 100} < 011 > ~ { steel of the crystal grain of 223} < 110 > orientations, after stamping, may damage Flatness.For example, in the situation that backlight chassis for slim LCD TV is implemented to make length direction is the expansion forming of the elongated stiffening web shape of 45 ° of directions of rolling, exist on stiffening web length direction, to produce crest line warpage and because near the material of flange portion bulging portion flows into the problem that produces backlight chassis warpage.
In addition, in patent documentation 1 ~ 3, disclose reduce cold-rolled steel sheet cold rolling rate, particularly make r value be low to moderate 40% situation, but while being rolled with approximately 40% extremely low cold rolling rate, there is plate shape variation and make deteriorated and so on the problem of the Flatness of final goods.In addition, although above-mentioned low cold rolling rate improves shape freezing, be difficult to manufacture the steel sheet below about 1.0mm.
Therefore, the inventor's be conceived to be easy to get high ductibility and be difficult for producing and cause being shaped when stamping the ultra-low carbon steel of tension strain of fracture and fold.Conventionally, Ti is that the ultra-low carbon steel plates such as IF steel easily make the favourable recrystallize grain of high r value carry out grain growing in annealing operation, therefore, need to carry out low r value.In order to carry out low r value, carrying out recrystallize but crystal grain is difficult for annealing under the low temperature of growth, therefore, need under only demonstrating the condition of variation of several degrees Celsius at most, soaking temperature control annealing conditions.But in real machine, the different material of soaking temperature of setting during annealing passes through continuous annealing apparatus successively, therefore, exists soaking temperature to change the approximately situation of tens of degrees Celsius, is difficult to soaking temperature to be controlled at several degrees Celsius with interior scope.Therefore, there are the following problems: at the temperature higher than target temperature, anneal, thereby can not realize low r value.In patent documentation 1 ~ 3, also there is same problem, for the condition of annealing temperature, although on the books, do not have consideration accurately to control the difficulty of annealing temperature.
In view of the foregoing, the object of the invention is to solve the problem of above-mentioned prior art, and provide can carry out that deep-draw processing, bending machining, bulging are processing, that can guarantee the desired shape of large component, plasticity and shape freezing is good and real machine is manufactured cold-rolled steel sheet and the manufacture method thereof of excellent in stability.
For the method for dealing with problems
In order to address the above problem, contriver conducts in-depth research investigation repeatedly.As a result, find following aspect.First, even carry out in order to take into account processibility and the high shape freezing that complicated processing also can not produce warpage, importantly make the annealed sheet after cold rolling control r value under the state that keeps high ductibility.That is,, by increasing average elongation, can guarantee that deep-draw processing, bulging add the processibility in man-hour, and can guarantee the desired shape of parts.And then, by reducing the r value of rolling direction, rolling right angle orientation and 45 ° of these three directions of direction of rolling and making average r value in specialized range, in the situation that implement to make length direction, be that the expansion forming of the elongated stiffening web shape of 45 ° of directions of rolling also can prevent warpage, rear generation resilience, warpage can be suppressed to process, thereby shape freezing can be guaranteed.
By measuring to arrange the soaking temperature scope in annealing operation according to rolling rate, Nb amount and B, can in the situation that need not accurately controlling soaking temperature, stably manufacture.
The present invention is based on above-mentioned opinion and complete, its purport is as follows.
(1) a kind of cold-rolled steel sheet, it is characterized in that, there is following composition: in quality %, C:0.0010 ~ 0.0030%, Si:0.05% are following, Mn:0.1 ~ 0.3%, P:0.05% is following, S:0.02% is following, Al:0.02 ~ 0.10%, N:0.005% are following, Nb:0.010 ~ 0.030%, B:0.0010≤B-11/14 * N≤0.0050%, surplus is iron and inevitable impurity
And, the average elongation (El being represented by following (a) formula
m) be more than 42%, the average r value (r being represented by following (b) formula
m) be 1.2 ~ 1.6,
Average elongation El
m=(El
l+ 2El
d+ El
c)/4 ... (a)
Average r value r
m=(r
l+ 2r
d+ r
c)/4 ... (b)
At this, El
l: the elongation of rolling direction, El
d: the elongation of 45 ° of directions of rolling, El
c: the elongation of rolling right angle orientation, r
l: the r value of rolling direction, r
d: the r value of 45 ° of directions of rolling, r
c: the r value of rolling right angle orientation.
(2) cold-rolled steel sheet as described in above-mentioned (1), it is characterized in that, in quality %, also contain Ti:0.005% ~ 0.020%, and replace above-mentioned B:0.0010≤B-11/14 * N≤0.0050% with B:0.0015 < B-11 * (| N/14-Ti/48|+ (N/14-Ti/48))/2≤0.0050%.
(3) a kind of manufacture method of cold-rolled steel sheet, it is characterized in that, the steel billet of above-mentioned (1) or above-mentioned (2) described composition is heated under more than 1150 ℃ Heating temperatures, then, carry out finishing the hot rolling of finish to gauge under more than 880 ℃ finishing temperatures, at 700 ℃, batch below, implement pickling, rolling rate with 55 ~ 80% is carried out cold rolling, then, according to this rolling rate CR (%), Nb amount, (quality ppm) and B measure (quality ppm), carry out under the soaking temperature of (820+Nb/15+B-CR) ~ 860 ℃, keeping the annealing of 30 ~ 200 seconds, then carry out cooling.
It should be noted that, in this manual, represent that %, the ppm of the composition of steel is quality %, quality ppm.In addition, the cold-rolled steel sheet as object of the present invention also comprises the steel plate of cold-rolled steel sheet being implemented to the surface treatments such as electro-galvanizing, pot galvanize and obtaining.And, also comprise the steel plate that has applied on this basis tunicle by chemical conversion processing etc.
In addition, the backlight chassis, panel of refrigerator, air-conditioner outdoor unit etc. that steel plate of the present invention can be widely used as large-scale TV have planar portions and have implemented the general member of the household electrical appliances purposes of bending, bulging, slight deep-draw processing etc.And then, if use the present invention, for example can utilize the steel plate that thickness of slab is 0.8mm to manufacture the above backlight chassis of about 650mm * about 500mm (32V type).
Invention effect
According to the present invention, can access plasticity and the good cold-rolled steel sheet of shape freezing that can carry out deep-draw processing, bending machining, bulging processing.And, can be in the situation that the soaking temperature that need not accurately control while annealing utilizes real machine stably to manufacture plasticity and the good cold-rolled steel sheet of shape freezing.Thus, the desired writing board shape of large component can be guaranteed, thereby the members such as backlight chassis of large-scale LCD TV can be manufactured.
Accompanying drawing explanation
Fig. 1 means the figure of the relation of cold rolling rate (rolling rate) CR and soaking temperature and performance.
Fig. 2 means the figure of the relation of Nb (quality ppm)/15+B (quality ppm) and soaking temperature and performance.
The figure of the impact that soaking temperature when Fig. 3 means annealing is brought to average r value.
The whether suitable AT-ATO of index and the figure of the relation of average r value of soaking temperature when Fig. 4 means as annealing.
Fig. 5 means as the whether suitable AT-ATO of index of the soaking temperature in when annealing and the figure of the relation of average elongation.
Embodiment
Below, the present invention is described in detail.First, the chemical composition of steel plate of the present invention is described.It should be noted that, in the following description, content %, the ppm of composition element all represent quality %, quality ppm.
C：0.0010~0.0030%
C has the effect that reduces r value, and therefore, from the viewpoint of low r value, preferably a large amount of interpolation, is more than 0.0010%.But excessive interpolation can bring becomes the tension strain that produces the reason of fold when stamping, and due to the caused dispersion-strengthened steel plate high strength that makes of formation of solution strengthening, carbide, elongation reduces.Therefore, making C is more than 0.0010% and below 0.0030%.
Below Si:0.05%
Si is the element that solution strengthening ability is high, improves yield strength and significantly reduces elongation.Therefore, making Si is below 0.05%.
Mn：0.1~0.3%
Mn forms sulfide and improves hot short element.In order to obtain this effect, need to add more than 0.1%.On the other hand, owing to being the element that solution strengthening ability is high, yield strength being improved and make ductility variation, therefore, making to be limited to 0.3%.
Below P:0.05%
P is solution strengthening element, yield strength is improved and makes ductility variation.Therefore, making P is below 0.05%.
Below S:0.02%
S forms sulfide in the stage of hot-rolled sheet, becomes the reason that makes ductility variation.Therefore, making S is below 0.02%.
Al：0.02~0.10%
The avidity of Al and N is strong, has the solid solution N amount reduction while making cold rolling process, the effect of inhibition age hardening.In addition, the fine tendency of separating out of AlN of separating out is higher, suppresses grain growing in annealing operation.In order to obtain these effects, need to add more than 0.02%.But excessive interpolation causes manufacturing cost to raise, during hot rolling, making from austenite phase transformation is that ferritic temperature raises, and therefore, is difficult to complete rolling in austenitic area.Therefore, need to make A1 is below 0.10%.
Below N:0.005%
N is in a large number containing sometimes, and solid solution in steel becomes the reason of tension strain.Therefore, making N is below 0.005%.
Nb：0.010~0.030%
Nb fixes solid solution C with the form of precipitate, suppress tension strain.And then, the tendency of the grain growing when also thering is precipitate and be fine the separating out of NbC and suppressing to anneal.In order to obtain these effects, need to add more than 0.010%.But, the in the situation that of excessive interpolation, recrystallization temperature is excessively raise.In addition, cause cost to increase, therefore, the upper limit is set as to 0.030%.
B:0.0010≤B-11/14 * N≤0.0050% (in the situation that adding Ti, 0.0015 < B-11 * (| N/14-Ti/48|+ (N/14-Ti/48))/2≤0.0050%)
B is in the present invention as the element of essential condition, by it is existed with the form of solid solution B in steel, can in the annealing process after cold rolling, suppress ferritic grain growing, even also can control r value under high soaking temperature.In order to obtain this effect, need to when hot rolling, at high temperature separate out BN and have more than 0.0010% solid solution B afterwards.But, during excessive interpolation, form precipitate with C, elongation is reduced.For the above-mentioned reasons, be set as 0.0010≤B-11/14 * N≤0.0050%.Be preferably 0.0015 < B-11/14 * N≤0.0050%.
And then in the situation that adding Ti, the TiC thicker than NbC separates out, grain growing during annealing improves, and therefore, need to make the solid solution B amount with the effect that suppresses grain growing surpass 0.0015%.But, during excessive interpolation, form precipitate with C, elongation is reduced.For the foregoing reasons, adopt 0.0015% < B-11 * (| N/14-Ti/48|+ (N/14-Ti/48))/2≤0.0050% to replace the relational expression of above-mentioned B:0.0010≤B-11/14 * N≤0.0050%.Be preferably 0.0020%≤B-11 * (| N/14-Ti/48|+ (N/14-Ti/48))/2≤0.0050%.
In the present invention, on the basis of above-mentioned element, can the scope 0.005% ~ 0.020% contain Ti with following object.
The avidity of Ti and N is strong, at high temperature forms precipitate, have suppress the solution strengthening of solid solution N, by the fine dispersion-strengthened effect causing of separating out of AlN.In addition, also can in the situation that will improving elongation especially, add.In order to bring into play these effects, preferably add more than 0.005%.But excessive interpolation can promote separating out of TiC, not only reduce the effect of the grain growing in inhibition when annealing being brought by NbC, and cause manufacturing cost to raise, therefore, be limited to 0.020% on while making to add.
Composition except above-mentioned consists of iron and inevitable impurity.As inevitable impurity, for example can enumerate: the Cu below 0.05%, the Cr that easily from waste material, sneak into, and the Sn below 0.01%, Mo in addition, W, V, Ni etc.
With regard to steel plate of the present invention, it is more than 42% making the average elongation of obtaining by following (a) formula.Elongation and plasticity have good dependency, and elongation is larger, for example can expansion forming to higher.Therefore, the elongation needing is the bigger the better, and by average elongation is increased to more than 42%, can carry out deep-draw processing, bulging processing, thereby can guarantee the desired shape of parts.
It should be noted that, average percentage of total elongation can be measured and be obtained by method below.From rolling direction, 45 ° of directions of rolling and rolling right angle orientation, cut respectively JIS5 tension test sheet, according to JIS Z 2241, carry out tension test.Then, by following (a) formula, obtain.
Average elongation El
m=(El
l+ 2El
d+ El
c)/4 ... (a)
At this, El
l: the elongation of rolling direction, El
d: the elongation of 45 ° of directions of rolling, El
c: the elongation of rolling right angle orientation.
For steel plate of the present invention, making the average r value of obtaining by following (b) formula is 1.2 ~ 1.6.The warpage producing after r value and bending forming, expansion forming has dependency.In bending forming, the r value of bending direction increases, and thus, along bending line, obviously produces saddle type warpage.In addition, in expansion forming, by using high r value material, from the material of bulging portion flange part around, flow into and become significantly, at flange part, produce unrelieved stress and distortion.Therefore,, in order to improve the shape freezing after stamping by low r value, in the present invention, making average r value is below 1.6.On the other hand, excessive low r value meeting extremely reduces elongation, therefore, make average r value under be limited to 1.2.
It should be noted that, average r value can be measured and be obtained by method below.From rolling direction, 45 ° of directions of rolling and rolling right angle orientation, cut respectively JIS5 tension test sheet, the prestrain with 15% is carried out plastic strain ratio test according to JIS Z 2254.Then, by following (b) formula, obtain.
Average r value r
m=(r
l+ 2r
d+ r
c)/4 ... (b)
At this, r
l: the r value of rolling direction, r
d: the r value of 45 ° of directions of rolling, r
c: the r value of rolling right angle orientation.
In addition, for example, in the situation that the backlight chassis enforcement for slim LCD TV is made to length direction, it is the expansion forming of the elongated stiffening web shape of 45 ° of directions of rolling, the crest line warpage producing on stiffening web length direction and because near the material of flange portion bulging portion flows into the warpage of the backlight chassis producing becomes large when the r value of 45 ° of directions of rolling is high.Therefore, importantly reduce the r value of rolling direction, rolling right angle orientation and 45 ° of these three directions of direction of rolling, on the basis that is preferably 1.2 ~ 1.6 in average r value, preferably the maximum r value in rolling direction, rolling right angle orientation and these three directions of 45 ° of directions of rolling is less than 2.0.
Below, the manufacture method of cold-rolled steel sheet of the present invention is described.
In the present invention, the steel billet with above-mentioned composition is heated under more than 1150 ℃ Heating temperatures, then, carry out finishing the hot rolling of finish to gauge under more than 880 ℃ finishing temperatures, at 700 ℃, batch below, implement pickling, then with 55 ~ 80% rolling rate, carry out cold rolling, then, according to this rolling rate CR (%), Nb amount, (quality ppm) and B measure (quality ppm), carry out under the soaking temperature of (820+Nb/15+B-CR) ~ 860 ℃, keeping the annealing of 30 ~ 200 seconds, then carry out cooling, thus, can access high elongation rate, low r value.
Heating temperature: more than 1150 ℃
The steel of having adjusted composition is heated to 1150 ℃ and makes above precipitate solid solution.Lower than 1150 ℃ add, hankering, N, C are residual under the state of not solid solution, are batching while processing or during annealing, and carbide, nitride be fine separating out and cannot give full play to the effect of the grain growing while suppressing annealing not.Therefore, Heating temperature is more high better, is more than 1150 ℃, is preferably more than 1200 ℃.But, while excessively heating, on steel surface, generate thick oxide skin, thereby increase the cost of cleanup acid treatment, therefore, be preferably below 1300 ℃.
Finishing temperature: more than 880 ℃
Then carry out hot rolling.In finish to gauge frame when finish to gauge, in the time of need to be single-phase in austenitic area, be rolled.In the situation that austenite and ferritic two-phase region are rolled, there is larger variation with phase transformation in rolling load, therefore, is difficult to the load of controlled rolling frame, likely causes plate fracture.In addition, in ferrite area, single-phase rolling meeting promotes the residual of non-recrystallization, thereby ensuing rolling load in cold rolling is excessively increased, and may cause thus manufacturing cost to raise.For the above-mentioned reasons, finishing temperature is set as more than 880 ℃, when single-phase in austenitic area, carries out finish to gauge.It should be noted that, when finishing temperature is too high, oxide skin thickening, the cost of cleanup acid treatment increases, and therefore, is preferably below 950 ℃.
Preferably after finish to gauge, carry out water cooling.Knownly before cold rolling, make C, N solid solution and reduce r value, in order to suppress separating out of C, N, and the grain growing while suppressing to anneal for the carbide that makes to separate out, nitride miniaturization, preferably carry out above-mentioned cooling.
Coiling temperature: below 700 ℃
As the final operation of hot rolling, below 700 ℃, coils of hot rolled is being batched.When coiling temperature surpasses 700 ℃, Al, Nb, Ti at high temperature form carbide, nitride, from guaranteeing that to bring the viewpoint of solid solution C, solid solution N impact cold rolling be not preferred to reducing r value.It should be noted that, when coiling temperature is too low, the winding form variation of coiled material, therefore, is preferably more than 400 ℃.
Rolling rate (CR) when cold rolling: 55 ~ 80%
Utilize usual method to carry out pickling to hot-rolled sheet.Then, be rolled rate (CR) and be cold rolling more than 55% and below 80%, be configured as the thickness of slab of expectation.When rolling rate (CR) is less than 55%, tissue forms mixing crystal grain and ductility is extremely reduced.On the other hand, rolling rate (CR) higher than 80% time, easily forms reducing the disadvantageous texture of r value after annealing.
Soaking temperature: (820+Nb/15+B-CR) ~ 860 ° of C, hold-time: 30 ~ 200 seconds
Then, as annealing operation, according to rolling rate CR (%), Nb amount, (quality ppm) and B measure (quality ppm), under the soaking temperature of the scope of (820+Nb/15+B-CR) ~ 860 ℃, keep 30 ~ 200 seconds.Then carry out cooling.
In annealing operation, by recrystallize, make to disappear because of the strain of cold rolling introducing, thereby make steel plate softening.(CR) is higher for rolling rate, and particularly the amount of Nb, B is fewer to add element, and the temperature that completes recrystallize is lower.Therefore,, in order to prevent reducing because of the residual elongation that makes of non-recrystallization tissue, need to make soaking temperature is more than (820+Nb/15+B-CR).The restriction reason of this soaking temperature describes in the back.On the other hand, during the recrystallization temperature that exceedingly raises, except manufacturing cost raises, ferritic phase becomes austenite, and then when cooling from austenite to ferrite transformation, makes thus excessive tissue miniaturization and high strength occurs, and elongation decreases.Therefore, need to make soaking temperature is below 860 ℃.
In addition, the soaking hold-time is when too short, non-recrystallization tissue residue, and when long, grain growing is excessively carried out and r value is increased.Therefore, need to make the hold-time is more than 30 seconds and below 200 seconds.In addition, the cooling r of the preventing value after soaking increases because of excessive grain growing, therefore, preferably with 3 ℃/sec of above speed, carries out cooling.
At this, to the soaking temperature in when annealing being set as to (820+Nb/15+B-CR) above reason, describe particularly.Conventionally, while improving rolling rate, the motivating force of recrystallize increases, and the temperature (being called recrystallization temperature below) that completes recrystallize during annealing moves to low temperature side.On the other hand, while increasing the amount of the Nb, the B that add, recrystallize is significantly suppressed, and recrystallization temperature moves to high temperature side.According to the inventor's experiment, recrystallization temperature and rolling rate (CR), the Nb amount, the B measurer that add have correlationship.Fig. 1 means the figure of the relation of rolling rate (CR) and soaking temperature and performance, and Fig. 2 means the figure of the relation of Nb (quality ppm)/15+B (quality ppm) and soaking temperature and performance.At this, the chemical constitution for examination material in Fig. 1 is Nb:150ppm, B:30ppm, and in Fig. 2, rolling rate (CR) is 70%.Soaking temperature during except annealing, be the characteristic value of the annealed sheet of making within the scope of the invention.In addition, in each figure, by average elongation be more than 42% and the situation that on average r value is 1.2 ~ 1.6 is denoted as zero, the situation that does not meet above-mentioned value is denoted as *.Straight line in each figure be soaking temperature=(820+Nb/15+B-CR) (℃) straight line, and be by zero and * the good boundary line that separates.According to Fig. 1 and Fig. 2, the soaking temperature in when annealing be (820+Nb/15+B-CR) (℃) when above, can manufacture average elongation is more than 42% and plasticity and the good cold-rolled steel sheet of shape freezing that on average r value is 1.2 ~ 1.6.More than soaking temperature during for the above-mentioned reasons, by annealing is set as (820+Nb/15+B-CR).
It should be noted that, when enforcement is of the present invention, melting method can suitably be used common converter process, electric furnace process etc.Steel after melting is cast as after steel billet, directly implement hot rolling or cooling after under above-mentioned Heating temperature, heat, then implement hot rolling.In hot rolling, under above-mentioned finishing temperature, carry out, after finish to gauge, under above-mentioned coiling temperature, batching.After finish to gauge, there is no special stipulation to the speed of cooling till batching, as long as there is speed of cooling more than air cooling enough.In addition, can carry out as required 100 ℃/sec of above chillings.Then, after common pickling, implement above-mentioned cold rolling.In annealing (heating-all thermal treatment-cooling), under above-mentioned condition, heat ~ cooling.In order to improve erosion resistance, can near 480 ℃, by pot galvanize, carry out plating as required.In addition, after plating, also can reheat to more than 500 ℃ and make coating alloying.Or, can adopt the thermal history keeping etc. cooling midway.And then, can with the elongation below 2%, carry out temper rolling or leveling as required.In addition, in the situation that annealing is not implemented plating midway, can carry out electro-galvanizing etc.And then, can also on cold-rolled steel sheet and coated steel sheet, by chemical conversion processing etc., give tunicle.As above manufacture cold-rolled steel sheet of the present invention.
(embodiment 1)
Embodiments of the invention are described.To having the steel of chemical constitution shown in table 1, carry out melting, under the creating conditions shown in table 2,3, making is for examination material.In table 1, solid solution B refers to the value of B-11/14 * N.But in the situation that adding Ti, refer to the value of B-11 * (| N/14-Ti/48|+ (N/14-Ti/48))/2.In addition, in the situation that the value of calculating is to be designated as 0 below 0.The details of creating conditions is as follows.First, in hot-rolled process, will melt steel and at 1250 ℃, heat 1 hour, carry out roughing, finish to gauge.FT shown in table 2,3, CT are respectively finishing temperature and coiling temperature.The thickness of slab of hot-rolled sheet is 2.0 ~ 3.5mm.Then, carry out pickling before cold rolling process, being at room temperature rolling to thickness of slab is 0.6 ~ 1.0mm.Then, as annealing operation, with the rate of heating of 20 ℃/sec, be heated to each soaking temperature, under soaking temperature, keep, after 30 ~ 200 seconds, with the speed of cooling of 20 ℃/sec, being cooled to room temperature.CR shown in table 2,3, AT, ATO represent respectively cold rolling rolling rate, soaking temperature, (820+Nb/15+B-CR).After annealing, carry out elongation and be 1.0% temper rolling, obtain for examination material.For the confession examination material obtaining, investigation average elongation (El
m) and average r value (r
m).It should be noted that, for average elongation (El
m) and average r value (r
m), from the rolling direction (L direction) for examination material, 45 ° of directions of rolling (D direction), rolling right angle orientation (C direction), cut respectively JIS5 tension test sheet, elongation is by measuring according to the tension test of JIS Z 2241, and r value is measured with 15% prestrain according to JIS Z2254 as mentioned above.Then, by above-mentioned (a) formula and (b) formula, obtain average elongation (El
m) and average r value (r
m).The obtained results are shown in Fig. 3, Fig. 4, Fig. 5, and result is shown in table 2, table 3 in the lump with creating conditions.
Table 2
In the inventive example, average elongation is more than 42%, and average r value is 1.2 ~ 1.6, and plasticity and shape freezing are good.In addition, 41 ~ 44 create conditions and mechanical characteristics from the label 32 ~ 35 of table 2 and table 3, in the inventive example, demonstrate r value and be 1.2 ~ 1.6 and elongation be that the soaking temperature scope of more than 42% value is 800 ℃ ~ 850 ℃, in contrast, in comparative example, when solid solution B measures few composition system, do not observe demonstrate r value be 1.2 ~ 1.6 and elongation be the soaking temperature of more than 42% value.Therefore confirmed, in the inventive example, even high temperature annealing also can obtain low r value and high elongation rate and have good real machine manufacturing stability.
The figure of the impact that soaking temperature when Fig. 3 means annealing is brought to average r value.In the many inventive examples of solid solution B amount, though soaking temperature during annealing in higher range, average r value also can reach 1.2 ~ 1.6.
The whether suitable AT-ATO of index and the figure of the relation of average r value of soaking temperature when Fig. 4 means as annealing.When AT-ATO is negative, soaking temperature is improper, and recrystallize can not fully carry out, result, and average r value is less than 1.2.
Fig. 5 means as the whether suitable AT-ATO of index of the soaking temperature in when annealing and the figure of the relation of average elongation.When AT-ATO is negative, soaking temperature is improper, and recrystallize can not fully carry out, result, and average elongation is less than 42%.
Claims (3)
1. a cold-rolled steel sheet, is characterized in that,
There is following composition: in quality %, C:0.0010～0.0030%, Si:0.05% are following, Mn:0.1～0.3%, P:0.05% is following, S:0.02% is following, Al:0.02～0.10%, N:0.005% are following, Nb:0.010～0.030%, B:0.0010%≤B-11/14 * N≤0.0050%, surplus is iron and inevitable impurity
And, the average elongation (El being represented by following (a) formula
m) be more than 42%, the average r value (r being represented by following (b) formula
m) be 1.2～1.6,
Average elongation El
m=(El
l+ 2El
d+ El
c)/4 ... (a)
Average r value r
m=(r
l+ 2r
d+ r
c)/4 ... (b)
At this, El
l: the elongation of rolling direction, El
d: the elongation of 45 ° of directions of rolling, El
c: the elongation of rolling right angle orientation, r
l: the r value of rolling direction, r
d: the r value of 45 ° of directions of rolling, r
c: the r value of rolling right angle orientation.
2. cold-rolled steel sheet as claimed in claim 1, it is characterized in that, in quality %, also contain Ti:0.005%～0.020%, and replace described B:0.0010%≤B-11/14 * N≤0.0050% with B:0.0015% < B-11 * (| N/14-Ti/48|+ (N/14-Ti/48))/2≤0.0050%.
3. the manufacture method of a cold-rolled steel sheet, it is characterized in that, the steel billet forming described in claim 1 or 2 is heated under more than 1150 ℃ Heating temperatures, then, carry out finishing the hot rolling of finish to gauge under more than 880 ℃ finishing temperatures, at 700 ℃, batch below, implement pickling, rolling rate with 55～80% is carried out cold rolling, then, according to this rolling rate CR, Nb amount and B amount, carry out keeping the annealing of 30～200 seconds under the soaking temperature of (820+Nb/15+B-CR)～860 ℃, then carry out cooling, wherein, the unit of rolling rate CR is %, the unit of Nb amount and B amount is quality ppm.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2010-006554 | 2010-01-15 | ||
| JP2010006554A JP5056863B2 (en) | 2010-01-15 | 2010-01-15 | Cold rolled steel sheet and method for producing the same |
| PCT/JP2011/050586 WO2011087107A1 (en) | 2010-01-15 | 2011-01-07 | Cold-rolled steel plate and method for producing same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102712983A CN102712983A (en) | 2012-10-03 |
| CN102712983B true CN102712983B (en) | 2014-03-12 |
Family
ID=44304376
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201180006238.XA Active CN102712983B (en) | 2010-01-15 | 2011-01-07 | Cold-rolled steel plate and method for producing same |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JP5056863B2 (en) |
| KR (1) | KR101463667B1 (en) |
| CN (1) | CN102712983B (en) |
| MX (1) | MX354951B (en) |
| MY (1) | MY155323A (en) |
| TW (1) | TWI429757B (en) |
| WO (1) | WO2011087107A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102011056847B4 (en) * | 2011-12-22 | 2014-04-10 | Thyssenkrupp Rasselstein Gmbh | Steel sheet for use as a packaging steel and process for the production of a packaging steel |
| WO2015129191A1 (en) * | 2014-02-25 | 2015-09-03 | Ｊｆｅスチール株式会社 | Steel plate for crown cap, method for manufacturing same, and crown cap |
| KR102322713B1 (en) * | 2019-12-19 | 2021-11-04 | 주식회사 포스코 | Cold-rolled steel sheet having excellent heat-resistance and formability and manufacturing method therof |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1996026300A1 (en) * | 1995-02-23 | 1996-08-29 | Nippon Steel Corporation | Cold-rolled steel sheet and hot-dipped galvanized steel sheet excellent in uniform workability, and process for producing the sheets |
| CN1135940A (en) * | 1995-03-10 | 1996-11-20 | 川崎制铁株式会社 | Steel plate for tanks and manufacture thereof |
| CN1261408A (en) * | 1998-04-27 | 2000-07-26 | 日本钢管株式会社 | Cold rolled steel plate of excellent moldability, panel shape characteristics and denting resistance, molten zinc plated steel plate, and manufacture thereof |
| CN101135025A (en) * | 2006-08-31 | 2008-03-05 | 宝山钢铁股份有限公司 | Production of cold rolling high-strength ultra-deep-drawing steel plate by bell-type furnace and method for manufacturing same |
| CN101563475A (en) * | 2006-12-20 | 2009-10-21 | 杰富意钢铁株式会社 | Cold-rolled steel sheet and process for producing the same |
| WO2010010964A1 (en) * | 2008-07-22 | 2010-01-28 | Ｊｆｅスチール株式会社 | Cold-rolled steel sheet, process for production of same, and backlight chassis |
| JP2010150580A (en) * | 2008-12-24 | 2010-07-08 | Jfe Steel Corp | Steel sheet and method of manufacturing the same |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02156023A (en) * | 1988-12-09 | 1990-06-15 | Sumitomo Metal Ind Ltd | Manufacture of cold rolled steel sheet having good formability |
-
2010
- 2010-01-15 JP JP2010006554A patent/JP5056863B2/en active Active
-
2011
- 2011-01-07 MX MX2012008181A patent/MX354951B/en active IP Right Grant
- 2011-01-07 CN CN201180006238.XA patent/CN102712983B/en active Active
- 2011-01-07 MY MYPI2012002967A patent/MY155323A/en unknown
- 2011-01-07 KR KR1020127019805A patent/KR101463667B1/en active IP Right Grant
- 2011-01-07 WO PCT/JP2011/050586 patent/WO2011087107A1/en active Application Filing
- 2011-01-13 TW TW100101212A patent/TWI429757B/en active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1996026300A1 (en) * | 1995-02-23 | 1996-08-29 | Nippon Steel Corporation | Cold-rolled steel sheet and hot-dipped galvanized steel sheet excellent in uniform workability, and process for producing the sheets |
| CN1135940A (en) * | 1995-03-10 | 1996-11-20 | 川崎制铁株式会社 | Steel plate for tanks and manufacture thereof |
| CN1261408A (en) * | 1998-04-27 | 2000-07-26 | 日本钢管株式会社 | Cold rolled steel plate of excellent moldability, panel shape characteristics and denting resistance, molten zinc plated steel plate, and manufacture thereof |
| CN101135025A (en) * | 2006-08-31 | 2008-03-05 | 宝山钢铁股份有限公司 | Production of cold rolling high-strength ultra-deep-drawing steel plate by bell-type furnace and method for manufacturing same |
| CN101563475A (en) * | 2006-12-20 | 2009-10-21 | 杰富意钢铁株式会社 | Cold-rolled steel sheet and process for producing the same |
| WO2010010964A1 (en) * | 2008-07-22 | 2010-01-28 | Ｊｆｅスチール株式会社 | Cold-rolled steel sheet, process for production of same, and backlight chassis |
| JP2010150580A (en) * | 2008-12-24 | 2010-07-08 | Jfe Steel Corp | Steel sheet and method of manufacturing the same |
Also Published As
| Publication number | Publication date |
|---|---|
| MX354951B (en) | 2018-03-27 |
| WO2011087107A1 (en) | 2011-07-21 |
| TWI429757B (en) | 2014-03-11 |
| CN102712983A (en) | 2012-10-03 |
| MX2012008181A (en) | 2012-08-03 |
| TW201139697A (en) | 2011-11-16 |
| JP5056863B2 (en) | 2012-10-24 |
| KR20120099144A (en) | 2012-09-06 |
| MY155323A (en) | 2015-09-30 |
| KR101463667B1 (en) | 2014-11-19 |
| JP2011144428A (en) | 2011-07-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103228808B (en) | High-strength bake-hardening cold-rolled steel sheet and method for manufacturing same | |
| CN103857817B (en) | The high strength cold rolled steel plate that in deep drawing quality and coiled material, uniform in material is excellent and manufacture method thereof | |
| KR100500791B1 (en) | FERRITIC Cr-CONTAINING STEEL SHEET HAVING EXCELLENT DUCTILITY, FORMABILITY, AND ANTI-RIDGING PROPERTIES, AND METHOD OF PRODUCING THE SAME | |
| CN104419865B (en) | A kind of easy-open end cold-rolled tin plate and production method thereof | |
| CN103930585A (en) | Thin steel sheet and process for producing same | |
| CN105189804A (en) | High-strength steel sheet and method for manufacturing same | |
| CN104685086A (en) | Ferritic stainless steel sheet | |
| CN105917016A (en) | Ferritic stainless steel and method for producing same | |
| CN105378134A (en) | Steel sheet for can, and method for manufacturing same | |
| CN102712983B (en) | Cold-rolled steel plate and method for producing same | |
| CN112501502B (en) | Hot-rolled pickled thin plate strip and transverse fold control method thereof | |
| CN107964632A (en) | The excellent ferrite series stainless steel plate of molding processibility | |
| CN102105614B (en) | Cold-rolled steel sheet, process for production of same, and backlight chassis | |
| TWI731672B (en) | Low carbon steel sheet and method of manufacturing the same | |
| JP4214671B2 (en) | Ferritic Cr-containing cold-rolled steel sheet excellent in ductility, workability and ridging resistance and method for producing the same | |
| JP4102284B2 (en) | {100} <011> Cold rolled steel sheet manufacturing method with excellent shape freezing property with developed orientation | |
| CN104233062A (en) | Extra-deep drawing hot-galvanized steel plate produced by annealing in short time and production method thereof | |
| CN107541663A (en) | A kind of beverage can ferrostan and its production method | |
| CN102712974B (en) | Cold-rolled steel plate having excellent post-aging moldability and shape retention | |
| JP3302118B2 (en) | Manufacturing method of cold rolled steel sheet with excellent deep drawability | |
| CN102414334B (en) | Cold-rolled steel sheet with excellent formability, shape retentivity, and surface appearance and process for producing same | |
| CN114381580B (en) | Cover annealing process and manufacturing method of high corrosion-resistant weather-resistant steel | |
| CN102712981B (en) | Cold-rolled steel plate and method for producing same | |
| KR20190022127A (en) | Ferritic stainless steel with improved impact toughness at low temperature and method of manufacturing the same | |
| EP4353862A1 (en) | Hot-dip galvanized steel plate and manufacturing method therefor |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |