JP3425224B2 - High-rigidity super-formable surface-treated thin steel sheet for drawing or drawing and ironing cans - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION The present invention relates to a cold rolled steel sheet surface.
Tin plating film, tin plating film and further chrome
Coatings, phosphate coatings, chrome plating coatings and
Chromium hydrated oxide film or both surfaces
Apply a film, and apply resin coating on at least one surface.
Drawing or DI (drawing and ironing) processing with a film, etc.
Used for beverage cans such as beer, carbonated drinks and juices
The present invention relates to a surface-treated thin steel sheet for a container. [0002] 2. Description of the Related Art For containers for drawing or drawing and ironing.
The properties required for surface-treated steel sheets mainly include formability,
Can strength and corrosion resistance, but in recent years,
From the viewpoint of economical efficiency, thinner and harder steel sheets are being pursued.
You. In addition, from the viewpoint of resource recyclability,
Metal (Sn, Ni, Cr, etc.)
Is desired. [0003] Further, such as cola drinks and carbonated drinks
Because the contents use requires high corrosion resistance,
Although the inner surface coating (double coat) is required,
Double coat increases the number of processes and reduces productivity
The cost of cans rises and is not economical. Also prior to interior painting
Wastewater treatment of degreasing and chemical conversion liquids is complicated
Waste containing organic solvents generated during baking of interior paint
It is necessary to take measures against environmental issues such as the need for gas treatment.
You. From these facts, products that do not perform internal coating in the can manufacturing process
A drawn or drawn ironing can that can be manufactured by the can method is desired
I have. Conventional surface-treated steel sheets for containers are generally manufactured by
Pig-steelmaking-hot rolling-pickling-cold rolling-electrolytic cleaning-annealing-tempering pressure
It is manufactured by a process called roll-plating. In particular,
In order to make the steel sheet thinner and harder,
After that, secondary cold rolling is performed again, so-called double reduce
It is generally manufactured by (DR). [0005] However, the conventional double reduce
The material contains about 0.01% of C content in steel
As a result, the moldability during can manufacturing can be greatly degraded.
It is a problem. For example, if the hardness of the steel sheet (HR30T) is 75
When drawing and ironing to ~ 78, C in steel changes
Work hardening occurs due to the fixing action, and the yield point increases. So
When the hardness (HR30T) exceeds 80, the elongation at break is remarkable
descend. This phenomenon is particularly noticeable in the upper part of the can wall where the processing volume is large.
It is author. When the yield point rises, the bottom
Wrinkles during molding and low elongation at break
If it is lowered, flange cracks are likely to occur.
It has not been practically used for digging (DI) processing. [0006] In order to solve such problems,
An economical way to produce steel sheets with better formability
Japanese Patent Publication No. 41-18486 discloses the processing of cold rolled steel sheets.
In order to remove hardening, it is conventionally performed at 600 ° C or higher.
Anneal process, strain relief annealing that does not cause recrystallized structure
Has been proposed. When performing strain relief annealing
Work hardening is removed. [0007] Furthermore, Japanese Patent Publication No. 54-1244 discloses
"C: 0.005% to 0.03%, Mn: 0.10 to 0.10%
1.00%, Si: 0.05% or less, the balance being substantially iron
The steel is cold-rolled at a rolling reduction of 80% or more,
Cold-rolled as it is without annealing after cold-rolling
Steel sheet for cans with excellent workability "
Despite good shallow drawability such as
Thin steel plate that can withstand drawing and ironing has been commercialized
Not. Further, it has excellent corrosion resistance and drawability and ironing workability.
As a steel sheet, there is Japanese Patent Publication No. 50-10526. The
The official gazette states that `` Steel obtained by the normal steel plate manufacturing method
The composition of the plate is C <0.019% (in the examples, 0.005%).
5 to 0.006%), Si <0.3%, Mn: 0.09
% To 1.0%, S: 0.02 to 0.10%, O <0.0
2% and S (%) / P (%)> 1, with the balance being
Corrosion resistance and iron ani characterized by being substantially composed of iron
Steel sheet for carbonated beverage cans with excellent graining structure
Has excellent corrosion resistance to cola-based carbonated beverages
A steel plate is disclosed. However, the steel sheet is drawn and ironed
In order to ensure heat resistance, annealing and tempering after cold rolling
Rolling process is indispensable, and the steel in the annealing and temper rolling processes
No problem of plate surface flaws and economically advantageous cold
It was not possible to use it. [0009] SUMMARY OF THE INVENTION The present invention relates to a recent steelmaking process.
With the rapid development of technology, the content of impurity elements in steel
Taking advantage of the fact that it has become possible to control
Cold rolling as it was impossible with conventional technology
Excellent drawing or drawing and ironing processability
High strength that can secure the pressure resistance of the can when thinning
Temperature, the economics of being usable in the cold state, etc.
Surface treated steel sheet for containers that simultaneously satisfies the properties
Tin plating or further chromate treatment on the steel plate surface
Surface treated steel sheet, recycled to the surface treated steel sheet surface
Treated steel for containers with a phosphate coating that is also advantageous
Sheet or the surface-treated steel sheet surface is also environmentally friendly
Surface treatment of container-treated steel sheet for containers with various resin coatings
It is intended to provide a thin steel sheet. The present inventors have disclosed Japanese Patent Publication No. 54-1244.
According to the report, cold-rolled as-rolled steel with a C content of 0.005 to 0.03%
Regarding the material, it was explained that the lid made is good
However, the ironing workability of this material is far from practical, and
Japanese Patent Application Laid-Open No. 50-10526 discloses a C content of 0.005 to 0.5.
Ironing workability after annealing for 006% material
It was explained that the corrosion resistance is good,
Ironing workability as cold rolled is far from practical
It was state. High strength with excellent ironing processability
I have been conducting research for many years in search of steel sheets, but as a result,
The C content in steel is controlled to an extremely low level of 0.0040% or less.
Composition, such as C content, Ti content, Nb content, etc.
Balance the ratio of long to short diameter, that is, the grain axis ratio
Optimized for ironing and flange formation
In the area where the formability, that is, can-making property and can strength, can be satisfied simultaneously
I finally found something. [0011] Among the above can-making properties and can strength,
Fig. 1 shows the knowledge of can making (ironing workability).
You. Fig. 1 shows the C content and criticality in the ultra-low C region.
It shows the relationship between the earning (ironing) rates. This
The critical ironing rate of
The ratio of the can wall thickness to the original sheet thickness at the time of squeezing, that is, "(t_o−
t_w) / T_o, T_o: Original thickness, t_w: Can wall thickness ”.
From FIG. 1, in the ultra-low C steel, the C content is 0.0040.
% Or less, particularly 0.0020% or less, depends on the grain axis ratio.
Critical ironing rate rises dramatically to nearly 90%
It became clear that it reached. Normal beverage cans (contents
In order to manufacture DI cans with a volume of 350 ml), about 6
An ironing rate of 5% is used.
With a world ironing rate, stable can-making work is possible.
You. Thus, in the ultra-low C region, the grain axis ratio is critical.
Ironing process with little effect on earing rate
It was found that good results were obtained for [0012] The knowledge of can-making properties (flange formability)
Is shown in FIG. Fig. 2 shows the ultra-low C region.
And the critical flange forming thickness, ie, D,
Flange cracking occurs during flange forming after I processing
It shows the relationship with the limit flange thickness. This is
In the case of ultra-low C steel, the addition amount of Ti + Nb is 0.0
If it is at least 05%, the flange formability will be improved, and
It can be seen that the edge thickness is reduced. Also this effect is crystal
It hardly depends on the grain axis ratio. Therefore, Ti + Nb addition
Steel with an amount of 0.005% or more is a very stable flange
It is possible to change the shape of the DI can neck and reduce the neck diameter
It is clear that this can also be handled. ◎ On the other hand, Ti + N
b Withstands the production of cans even with less than 0.005% steel
Although it has flange formability, it has high flange processing stability and DI
Lack of flexibility in selection of can neck shape and diameter. Next, the present inventors will show their findings on can strength.
Table 1 shows the results. The present inventors have developed a thin DI can
For the purpose, low carbon steel with C content of 0.0040% or less
Check the range of the grain axis ratio required to secure the steel sheet strength.
As a result of discussion, the grain axis ratio, tensile strength,
And the relationship with hardness. As the can strength, tensile strength 7
0kg / mm^TwoAbove, hardness (HR-30T) 75 or more is required
You. [0014] [Table 1] As described above, the present inventors have shown in FIGS.
Like ironing and flange workability and high strength
Found a region that satisfies all requirements, and has excellent can-making properties and can strength
Developed a surface-treated steel plate compatible with [0016] [MEANS FOR SOLVING THE PROBLEMS]
The gist of the present invention is     C: 0.004% or less S: 0.02% or less     Al: 0.2% or less, N: 0.008% or less,     At least one of Ti and Nb: 0.005 ≦ Ti (%) + Nb (%)     ≤0.1% And the balance is composed of Fe and unavoidable impurities.
And the ratio of the major axis to the minor axis of the crystal grains is 4 on average.
Having the above grain structure,The average surface roughness is 0.05
It is up to 3.0 μRaSurface treatment of steel sheet as it is cold rolled
Squeezing or drawing ironing can height
It is a rigid super-formable surface-treated thin steel sheet. [0017] The reasons for limiting the numerical values of the present invention will be described below. C: The smaller the C content, the better. The upper limit of the amount of C is 0.00
The reason for 4% is that if it exceeds 0.004%, after DI processing
Wrinkles during neck-in processing and flange processing of can walls
As well as flange cracks
It is. In addition, neck-in processing with a thinner plate, franc
When performing machining, the C content should be 0.002% or less.
The effect is great. And the steel sheet has a C content of 0.004%
And at least one of Ti and Nb is Ti and N
b Crystals containing 0.005% or more in total and having an average of 4 or more
Good can-making properties and can strength by having a structure with a grain axis ratio
You can get the degree. S: S is not an element to be added. S
The reason that the upper limit of the amount is 0.02% is that it exceeds 0.02%.
This is because DI processability during can making deteriorates. Al: Al is added as a deoxidizing agent and remains.
What is the upper limit of 0.2%? Al 0.2%
If it exceeds, the ductility deteriorates and the crack occurrence rate during flange processing increases.
Because it has an adverse effect such as high
is there. The amount of Al should be less than the stability during processing
It is more preferable that the content is 0.08% or less. N: N is not an element to be added. The upper limit of N amount
The value of 0.008% means that N exceeds 0.008%.
If it is present, the rate of cracking during flange processing will increase
It is. Ti, Nb: At least one of Ti and Nb is Ti
(%) And Nb (%) in total of 0.005% or more
Then, the flange workability is improved as described with reference to FIG.
This is because Ti or Nb forms carbonitride, and solid solution C, N
And to reduce the grain size of the hot-rolled sheet
Conceivable. The upper limit is the sum of Ti (%) and Nb (%).
0.1% means that the effect is saturated even if it is added more than that.
Because it is not economical. Grain axis ratio: to the minor axis of the crystal grain of the steel sheet
The reason that the ratio of the major axis, that is, the crystal grain axis ratio was 4 or more on average was
If this is less than 4, the strength of the steel plate will be low, and the strength of the can will be secured.
In order to achieve this, it is necessary to increase the thickness of the steel sheet, which is not economical.
Because it is. If the thickness is smaller, the grain axis ratio
If the average is 30 or more, more stable can strength can be secured.
It is. The steel sheet of the present invention is usually hot-rolled and pickled.
Is manufactured by cold rolling
Finishing and winding temperatures at rolling and cold rolling reduction
By controlling the ratio, the grain axis ratio of the present invention is obtained.
Further, after hot rolling, the crystal grains of the hot rolled steel sheet are reduced by means such as rapid cooling.
Grain makes it more stable and increases the strength of the steel plate.
Good moldability can be maintained. There is also cold rolling
The hardening allowance after drawing or drawing and ironing
Machining while maintaining elongation characteristics due to low yield rise
It is characterized by good properties. And aperture or aperture
Neck-in workability,
This is to ensure runge workability, which is impossible in the past.
To achieve a drawn or drawn ironing can made of thin steel material
Things. In addition, due to these excellent characteristics, the cooling
Of the workability and strength required after cold rolling.
Workability and strength without annealing and temper rolling
Very easy and economical production of excellent materials.
And it is possible. However, the rolling oil is applied to the steel sheet surface as it is cold-rolled.
If iron powder or iron powder is attached,
It is important to note that deposits on the surface may be removed by electrolytic cleaning, etc.
Needless to say. The thickness and roughness of the cold-rolled steel sheet are particularly
Although not specified, the thickness should ensure the strength after making the can.
In addition, 0.06 mm or less is desirable from the viewpoint of weight reduction.
0.10 to 0.25 mm, surface roughness
Securing a delicate pool of lubricant and punching during can making
To prevent strip-out,
No stable friction and no generation of iron powder.
With an average roughness of 0.05 to 3.0 μRa
It is. In the surface treatment of the present invention, the steel sheet
Tin-plated film, tin-plated film and
Mate film, phosphate film, chrome plating film and on it
In addition, chromium hydrated oxide film or both surfaces
A resin coating on at least one surface.
A film such as a film is applied. Below is an example
You. First, the above cold-rolled steel as a base
When the plate is subjected to Sn plating or further chromate treatment
The case is described below. In this case, the surface
It is the same as that used for ordinary tin cans.
Is used. The amount of Sn adhesion is 0.5 to
5.5 g / m^TwoThe degree is used. Make sure the amount
It is not necessary that both sides be the same. For example, the place of DI can
In the case, the side used for the inner surface of the can has the required corrosion resistance and
Sn adhesion due to the lubricity required for internal ironing
The amount is determined and the side used for the outer surface is when ironing the outer surface
Required for lubrication and external appearance
The amount of Sn adhesion is determined. A chromate film is formed on the Sn plating film.
Otherwise, the surface has good wettability with water.
Water quality, e.g., SS, hardness in the can water washing process in the can process
Water pattern on the inside of the can, especially on the bottom of the can
Surface treatment,
Only Sn plating may be used. Also, due to the aging oxidation of Sn
Chromate skin on Sn plating to prevent yellowing
It is also effective to apply a film. Especially the type of chromate film
Although not limited, for example, a Sn-plated steel sheet
Immersion or immersion in sodium chromate or chromic acid aqueous solution
Is obtained by electrolytic treatment. Cr
0.1 to 50 mg / m^Twodegree
Is applied. The adhesion amount is not necessarily on both sides
It need not be the same. For ironing of DI cans
If it can be used, in the chromate film from the viewpoint of galling resistance
It is desirable that the lower the amount of metallic chromium, the better
New Aperture using thin hard tinplate as described above
Or cans obtained by drawing and ironing
It has superior corrosion resistance compared to cans manufactured using
The thinner thickness allows for a lighter can weight and less material usage
Not economical. Next, the cold-rolled steel as the base
The following is the case where the plate is subjected to a lubricating film treatment with phosphate.
Will be described. In this case, the plating applied to the surface is a normal D
Instead of Sn plating used for tin cans,
Phosphate treatment is used as a lubricating film treatment. Processing method is
Although not particularly specified, for example, iron phosphate,
Lead, calcium phosphate, zirconium phosphate, chromate phosphate
Are used. The amount of adhesion varies depending on the type of film.
However, for iron phosphate-based coatings, 0.05 to 0.5 g / m^TwoAbout
0.5 to 4 g / m2 for zinc phosphate coating^TwoAbout
You. Also, the adhesion amount does not necessarily have to be the same on both sides.
No. For example, in the case of DI cans, the side used for the inner surface of the can is
After that, degreasing, chemical conversion treatment and inner coating
The amount of adhesion is determined by the lubricity required for ironing the surface.
In other words, the side used for the outer surface is necessary when ironing the outer surface
The amount of adhesion is determined by the lubricity and external printability
Can be These surface-treated steel sheets lubricate and cool the surface
Water-soluble synthetic lubricating oil or mineral oil
After being coated, it is drawn and ironed.
It is. Using a thin hard lubricated steel sheet as described above,
The cans obtained by the ironing process
Better corrosion resistance than cans manufactured using
Light weight and light material use due to thinness
Is economical, and Sn adheres to the steel sheet surface.
Less restrictions on reuse and less recyclability
Is also excellent. Further, the cold-rolled steel sheet as a base
After surface treatment, further on one side or both sides
The case of applying a resin film will be described below. Surface treatment leather
Films and resin films are always the same type and quantity.
No need to be. Especially the surface treatment film applied to the surface
Not limited, tinplate, tin free steel, etc.
Film used on steel plates for containers, namely electrolytic chromic acid
Treated film, chromate film or phosphoric acid skin as required
Sn plating film with film, chromate skin if necessary
Ni plating film with film, chromate skin as required
Aluminum plating film with film, phosphate film etc. are used
You. Here, the electrolytic chromic acid-treated film refers to tin
It is used as a free steel coating,
The lower layer obtained by electrolytic treatment in chromic acid aqueous solution
The upper layer has a two-layer structure of chromium hydrated oxide.
You. A chromate film is an aqueous solution of chromic acid or heavy
Electrolytic treatment or immersion treatment in aqueous sodium chromate solution
It is a film obtained by the above method. As a phosphate film,
Although not specified in, iron phosphate, zinc phosphate, potassium phosphate
Use of Lucium, Zirconium Phosphate, Phosphate Chromate, etc.
Can be The amount of adhesion varies depending on the type of coating,
0.05-0.5g / m for iron-acid based coating^TwoDegree, phosphorous acid
0.5 to 4 g / m for lead coating^TwoIt is about. The side whose surface is covered with the resin film is a resin
It is desirable to have excellent adhesion to the film.
Has electrolytic chromic acid film on treated film or Sn film
With electrolytic chromic acid coating on Ni plating film
Are used. Electrolysis to ensure adhesion
As the chromic acid treated film, the upper layer of hydrated chromium oxide film
The amount is 5 to 50 mg / m as chromium^TwoChrome, lower layer
7-150mg / m as chromium^TwoIf you want more
New When ironing the side used for the outer surface of the DI can
From the viewpoint of ensuring lubricity of Sn plating film and Sn plating
Having a chromate film on the film, or
A phosphoric acid film or the like is desirable. In this case, on the Sn plating film
The chromate film is a chromate film from the viewpoint of galling resistance.
The lower the amount of metallic chromium in the inside, the better
desirable. The resin film on the surface treatment film is particularly limited.
Not epoxy, phenolic, polys
Dissolve thermosetting resin such as
After dissolving or dispersing, apply and heat to remove the solvent.
Type that cures the resin layer and forms a resin film.
And polyester, polyolefin, polyamide
Need to directly bond thermoplastic resin film such as
To form a resin film by bonding through an adhesive layer according to
Although there is a type, both types can omit painting at the time of can making
Yes, effective for improving can making efficiency. As an example of the former,
Poxyphenol-based curable resins are exemplified. The latter
As an example, the crystal melting temperature of the resin is 180 to 265 ° C.
Polyester thermoplastic resin is used in the canning process
Can withstand squeezing and ironing while drying and
It is said that it can withstand the heat of surface painting printing
You. Using the thin hard resin-coated steel sheet as described above
The cans obtained by drawing or drawing and ironing are
Superior corrosion resistance compared to cans manufactured using conventional tinplate
The material thickness is thin and the can weight is light,
It is economical due to the small dose, and the coating process and
Degreasing, chemical conversion, wastewater treatment, waste gas
Because part of the processing can be omitted, it is excellent in resource saving and environmental aspects
ing. Alternatively, the cold-rolled steel as a base
Chromium plating film on plate surface and further hydration of chromium on it
Surface coated with oxide film (Tin free steel)
Processing may be performed. The can-making process described here is generally applied to beverage cans and the like.
Processing used in 1-stage or multi-stage drawing of two or more stages
Processing, or one or more stages of drawing followed by one or more stages
After drawing, bottom forming, neck if necessary
In-mold, flange molding, overhang molding, etc.
To the inner and outer surfaces as necessary during those processes.
May be subjected to grease, chemical conversion treatment and painting / printing. [0036] 【Example】 [Embodiment 1] The cold-rolled steel sheet according to this embodiment is a steelmaking
The slab is continuously cast from steel whose composition has been adjusted
Cold rolling after removing surface scale in pickling process after cold rolling
And used. Table 2 shows the present invention and comparative examples
Composition of steel and crystal axis ratio (with respect to the minor axis of crystal grains)
(Average value of the ratio of the major axis). [0037] [Table 2] Table 3 shows the results obtained by using the steels shown in Table 2 under the following conditions.
The above cold-rolled steel sheet, which is the base of
About n plating and further chromate treatment
It is an evaluation result.       Can making conditions: First stage drawing Blank ratio 144mm                                   Aperture ratio 1.65                 Redrawing process Drawing ratio 1.26                 Ironing process Total ironing rate 65%                 Neck-in process Can wall diameter 211mmφ                                   Neck diameter 206mmφ Board pressure: 0.20mm Surface roughness: average roughness 1.3 μmRa Plating: Sn plating adhesion amount 2.8 g / m^Two Pressure resistance: 5 kg / cm internal pressure for the DI can^TwoLoad the can bottom
Investigated whether or not caused plastic deformation. Can making characteristic evaluation: Shown by the number of good cans among the number of cans evaluated
You. Example) 15/20: 15 out of 20 cans are good [0039] [Table 3] No. 3 in Table 3 1 to 6, 10 to 14 of the present invention
It is a steel plate. No. C exceeds 0.004% as in 7
For bottom wrinkles, neck in wrinkles, flange cracking
No. S exceeds 0.02% as in 8
In some cases, DI processability is deteriorated. No. Like 9
If N exceeds 0.008%, the flange cracking resistance deteriorates.
ing. No. No. 15 has a crystal grain axis ratio of less than 4 and inferior compressive strength
ing. Example 2 Table 4 uses the steel of Table 2 and
The above-mentioned cold pressure which is the basis of the present invention and the comparative example under the following conditions
When the as-rolled steel sheet is subjected to a lubricating coating treatment with phosphate
This is the result of evaluation. In addition, steel plate manufacturing conditions,
Conditions, thickness, surface roughness, pressure strength evaluation method, hot working cracking
Evaluation method and cola-based carbonated beverage corrosion resistance evaluation method
Is the same as “Example-1”. Surface treatment: Sn plating adhesion amount 2.8 g / m^Two Chromate coating amount (Cr equivalent) 1.2mg / m^Two [0042] [Table 4] In Table 4, No. 1 to 6, 10 to 14 of the present invention
It is a steel plate. No. C exceeds 0.004% as in 7
For bottom wrinkles, neck in wrinkles, flange cracking
No. S exceeds 0.02% as in 8
In some cases, DI processability is deteriorated. No. Like 9
If N exceeds 0.008%, the resistance to flange cracking is poor.
Is becoming No. 15 has a compressive strength with a grain axis ratio of less than 4
Is inferior. Example 3 Table 5 uses the steel of Table 2 and
The above-mentioned cold pressure which is the basis of the present invention and the comparative example under the following conditions
When as-rolled steel plate is subjected to a lubricating film treatment with phosphate
This is the result of evaluation. In addition, steel plate manufacturing conditions,
Conditions, thickness, surface roughness, pressure strength evaluation method, hot working cracking
Evaluation method and cola-based carbonated beverage corrosion resistance evaluation method
Is the same as “Example-1”. Surface treatment: Iron phosphate coating weight 0.2g / m^Two  Table 5
No. 2,4-15 2.0g / m zinc phosphate coating weight^Two  No. of Table 5 1,3 [0045] [Table 5]No. 5 in Table 5 1 to 6, 10 to 14 of the present invention
It is a steel plate. No. C exceeds 0.004% as in 7
What is bottom wrinkle, neck in wrinkle, flange cracking
No. S is 0.02% like 8
If it exceeds, DI processability is deteriorated. No. 9
If N exceeds 0.008%, the flange cracking resistance becomes poor.
Has deteriorated. No. 15 has a high withstand pressure with a grain axis ratio of less than 4
Inferior degree. Example 4 Table 6 uses the steel of Table 2 and
The above-mentioned cold pressure which is the basis of the present invention and the comparative example under the following conditions
After performing surface treatment on the steel sheet as it is,
Or the case where resin coating is applied to both sides
You. In addition, steel plate manufacturing conditions, can making conditions, plate thickness, surface roughness,
Compressive strength evaluation method, hot working crack evaluation method, cola-based coal
The same method as in Example 1 was used for the evaluation method of the corrosion resistance of acid beverages
It is. Surface coating Inner side of can: Electrolytic chromic acid treated film Table 6 No. 1,3 80mg / m metal chromium adhesion^Two Oxide chromium adhesion amount (Cr equivalent) 18mg / m^Two Polyethylene terephthalate resin film 30μm Sn plating Table 6 No. 2,4-16 Sn plating adhesion amount 2.8g / m^Two Chromate coating amount (Cr equivalent) 1.2mg / m^Two Polyethylene terephthalate resin film 30μm Outer side of can: Sn plating Sn plating adhesion amount 2.8g / m^Two Chromate coating amount (Cr equivalent) 1.2mg / m^Two [0048] [Table 6]No. of Table 6 1 to 6, 10 to 14 of the present invention
It is a steel plate. No. C exceeds 0.004% as in 7
For bottom wrinkles, neck in wrinkles, flange cracking
No. S exceeds 0.02% as in 8
In some cases, DI processability is deteriorated. No. Like 9
If N exceeds 0.008%, the resistance to flange cracking is poor.
Is becoming No. 15 has a compressive strength with a grain axis ratio of less than 4
Is inferior. [0050] According to the present invention, a steel sheet as cold rolled can be treated.
Surface treated to withstand severe drawing or drawing and ironing
Surface treatment with excellent rigidity and high rigidity
Because it can provide steel plates, the material for cans can be made thinner and lighter.
Various forms, resource recyclability, can manufacturing process
Economically and easily manufacture cans that are excellent for environmental issues
Can be

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a critical ironing rate and a crystal grain axis ratio in an ultra-low C region. FIG. 2 is a diagram showing a critical flange forming thickness and the addition amounts of Ti and Nb in an ultra-low C region.

──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Keishi Ichikawa 1-1, Hibata-cho, Tobata-ku, Kitakyushu-shi, Fukuoka Prefecture Inside Nippon Steel Corporation, Yawata Works (72) Inventor Shinsuke Hamaguchi Hibata, Tobata-ku, Kitakyushu-shi, Fukuoka No. 1-1, Nippon Steel Corporation Yawata Works (56) References: Japanese Patent Publication No. 54-1244 (JP, B1) Japanese Patent Publication No. 2-42885 (JP, B2) (58) Fields surveyed (Int) .Cl. ⁷ , DB name) C22C 38/00-38/60

Claims (1)

(57) [Claims 1] C: 0.004% or less, S: 0.02% or less, Al: 0.2% or less, N: 0.008% or less, Ti by weight% And at least one of Nb: 0.005 to 0.1
%, The balance having a component consisting of Fe and unavoidable impurities, and having a crystal structure in which the ratio of the major axis to the minor axis of the crystal grains is 4 or more on average, and the average roughness of the surface is
A high-rigidity super-formable surface-treated thin steel sheet for drawn or drawn and ironed cans, wherein the steel sheet is cold-rolled and has a surface treatment of 0.05 to 3.0 μRa .