JPH01184229A - Production of steel sheet for di can having excellent stretch flanging property - Google Patents

Abstract

PURPOSE:To produce a steel sheet for DI cans (Draw and Ironed cans) having excellent stretch-flanging property by working a low-carbon Al killed steel ingot having a specific compsn. to a sheet material by hot rolling and cold rolling including a heat treatment under specific conditions. CONSTITUTION:The low-carbon Al killed steel ingot having the compsn. which contains, by weight %, 0.0040-0.060% C, 0.05-0.50% Mn, <0.02% P, <0.015% S, 0.020-0.100% acid soluble Al, and <0.0070% N and satisfies formula I between the contents [Mn] and [P] of Mn and P is hot rolled or when said ingot is once cooled down to the temp. below the Ar3 transformation point of this steel, the ingot is heated to the temp. T deg.C satisfying formula II or below and is hot rolled. The hot rolled sheet is coiled at 600-710 deg.C and is hot rolled; in succession, the sheet is subjected to recrystallization annealing for 5sec-3min at the recrystallization temp.-850 deg.C by continuous annealing. This steel sheet is then cooled at 5-250 deg.C/sec cooling rate and is subjected to an over aging treatment for 30-180sec at 300-500 deg.C. The steel sheet for DI cans which has <42kgf/mm<2> tensile strength, 8.5-11.5 crystal grain size number, the structure dispersion-strengthened with MnS of 0.02-0.40um average size and AlN of 0.005-0.20um and the excellent stretch-flanging property is produced.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is applied to DI cans (Draw & Ironed Cans).
) This relates to a steel plate for DI cans that has excellent stretch flange formability after DI processing, is easy to perform DI processing, and has improved pressure resistance by hardening during paint baking after DI processing.

(Prior Art) Surface-treated steel sheets, such as tin-plated steel sheets or tin-free steel sheets treated with chromic acid, are often used for food cans, aerosol cans, and easy-open cans.

In recent years, these surface-treated steel sheets have been subjected to severe processing such as multi-stage drawing processing or DI processing (Draw & Ironing processing, that is, ironing processing is performed after deep drawing processing), and they have not only good corrosion resistance but also excellent workability. is now also required.

The manufacturing process for DI cans involves shallow drawing a steel plate using a punch and die to form a cup, and then using a punch and die with a clearance smaller than the thickness of the side wall of the cup to draw and stretch the side wall to achieve the thickness of the side wall. A container (cup) of a predetermined depth is formed by reducing the amount, and a flange process is performed to wrap a lid around the end of the cup.

The characteristics required of a steel sheet for DI cans include good workability during DI processing, no galling and low processing energy, and high pressure resistance as a can body.

Conventionally, such materials for DI cans include, for example, B-added A
l Killed steel box annealed (Japanese Patent Application Laid-Open No. 53-48913
), box-annealed Cu-added low carbon steel (Special Publication No. 527
16965), box annealed materials were mostly used. This is because box annealed materials have better elongation and deep drawability, and are generally considered suitable for DI processing applications.

In particular, good stretch flange formability is extremely important in the molding process of DI cans, and the defective rate is several tens of ppm.
It is necessary to keep it below. Therefore, it stretches as a steel plate, r
Box annealed materials with excellent values have traditionally been used.

(Problems to be solved by the invention) On the other hand, in recent years, the thickness of DI cans has become thinner and thinner.
The demand for increasing compressive strength is also becoming very strong.

The compressive strength of the can body is determined by (plate thickness) x (strength), and to make it thinner, it is necessary to increase the strength of the material, but box annealed materials are generally soft and it is difficult to make them thinner. In order to improve the strength, it is necessary to add reinforcing elements to make it a relatively high-alloy component, and in this case, there is a problem that DI workability deteriorates. In addition, increasing the strength of the steel plate causes galling to occur more easily during DI processing, and processing energy also increases.

Recently, it has been considered to manufacture steel sheets for DI cans by continuous annealing, but it has not been possible to prevent the occurrence of small cracks in flange forming during DI processing, and galling is also occasionally observed. .

An object of the present invention is to provide a container material for DI cans that has excellent stretch flange formability, does not cause galling, is easy to perform DI processing, and has high pressure resistance after DI processing.

(Means for Solving the Problems) As a result of various studies conducted by the present inventors regarding the various characteristics required for DI cans, the inventors found that, when considering DI formability and practical characteristics of DI cans, the following results are obtained for steel sheets for DI cans: than box-annealed material.
Rather, the present invention was completed based on the new finding that continuously annealed steel sheets with specified strength, grain size, and precipitate size are superior.

The present inventors first deeply studied the stretch flange formability after DII processing, and found that the stretch flange formability after DII processing, that is, after significant processing, is different from the stretch flange formability of the steel sheet itself, and is rather contrary to conventional knowledge. In addition, the tensile strength of the steel plate is 42 kgf/mm2 or less, and the grain size number is 8.
5-11.5. MnS with an average size of 0.02 μm or more and 0.40 μm or less and 0.005 μm or more and 0.20 μm
It has an AlN precipitate structure with an average size of m or less, and C:0
．． 0040-0.0600%, Mn: 0.05-0
．． 50%, P: 0.02% or less, S: 0.01
5% or less, acid-soluble Al: 0.020-0.100%
, N: 0.0070% or less, but [Mn weight%
] and CP weight%] is 10 [P weight%]-0,03≦[Mn weight%]≦20
It was newly discovered that a continuously annealed steel material having a relationship of CP weight %]+0.14 has better stretch flange formability after DII processing, despite having solid solution C.

Furthermore, the present inventors hot-rolled a low-carbon Al-killed steel piece having the above-mentioned components to produce a product sheet with the above-mentioned characteristics.
After winding and cold rolling at a temperature of 0 to 710°C, then recrystallization annealing for 5 seconds to 3 minutes at a temperature of not less than the recrystallization temperature and not more than 850°C by continuous annealing method, and then 5-b 300- It has also been newly discovered that it is possible to produce it industrially by performing an overaging treatment at a temperature of 30 to 500°C at a temperature of 500°C.

The present inventors have found that in the continuously annealed material, the strength of the can body is significantly increased by the paint baking that occurs after DI processing, and as a result, the pressure resistance strength is also increased (hereinafter this property is referred to as B11 property). Ta. In other words, it has been found that by using the continuously annealed material, which is softer than the box annealed material, it is soft during DI processing, and therefore has excellent DII workability, and has excellent characteristics such that the compressive strength after painting is baked is higher than that of the box annealed material. did. This means that if the strength of the material is the same, the pressure resistance of the can body can be higher with the continuously annealed material, and this has great industrial value.

The present invention will be explained in detail below.

First, the tensile strength of the product plate (steel plate) will be explained with reference to FIG. If the tensile strength is large, the forming load and forming energy during DI processing will become large, making it difficult to process and more likely to cause galling.
/mm2. The preferred range is tensile strength of 40 kgf/m
m2 or less.

Figure 1 shows C: 0.0040-0.080%, Mn:
0.15-0.60%, P: 0.006-0.0
30%, S: 0.005-0.015%, acid soluble A
l: 0.005-0.070%, N: 0.00
For steel plates for DI processing made by melting less than 70% steel in a vacuum melting furnace and manufactured on a laboratory pilot line, the tensile strength of the product plate and the total forming energy in the DII experimental forming machine,
The relationship between the pressure resistance strength and the annealing method of DI cans that have been subjected to paint baking treatment after molding is shown below.

As shown in Figure 1, the tensile strength is 42 kgf/mm.
When it exceeds 2, the total forming energy increases significantly and galling occurs frequently, making DI processing difficult. In order to keep the total forming energy stably low, the tensile strength should be 40 kg.
f/mm2 or less, the yield point is preferably 36 kgf/mm2 or less, more preferably the tensile strength is 37 kgf/mm2 or less, and the yield point is 30 kgf/mm2 or less.

Further, the compressive strength increases as the tensile strength increases, but the compressive strength of continuously annealed material is about 1 to 2 kgf/mm2 higher than that of box annealed material even if the tensile strength is the same. In order to ensure such properties, it is preferable that the amount of solid solute C in the product board is 5.0 ppm or more.

Next, crystal grain size will be explained.

Figure 2 shows C: 0.0044-0.076%, Mn:
0.16-0.57%, P: 0.008-0.0
30%, S: 0.005-0.015%, acid soluble A
l: 0.007~o, o8o%, N: 0.00
20~0.0070% or less steel is melted in a vacuum melting furnace,
The relationship between the JISI grain size number, the processing rate until fracture occurs during stretch flange forming after DII processing, and the pressure resistance strength is shown in relation to the annealing method for a steel plate for DI processing manufactured on a laboratory pilot line.

It has been found that a stretch flange processing rate of 9.0% or more is evaluated as acceptable by the customer using the measurement method conducted in the laboratory of the present inventors.

As can be seen from Fig. 2, the stretch flanging rate improves as the grain becomes finer (the larger the grain size number), and in order to secure a stretch flanging rate of 9.0% or more, in the case of continuously annealed material, A grain size number of 8.5 or more is required. Also, contrary to expectations, the stretch-flange formability of the continuously annealed material is better than that of the box-annealed material. On the other hand, the finer the grain, the better the stretch flange formability and pressure resistance strength, but the steel becomes harder, and if the grain size number exceeds 11.5, the total forming energy during DI processing increases significantly, and galling occurs, so DI
Processing becomes difficult. Therefore, the grain size number is 8.5~
11.5. Preferably range 9.0-11.0
It's my turn.

Next, the dimensions of the precipitates on the steel plate will be explained.

Figure 3 shows C: 0.021-0.045%, Mn:
0.16-0.30%, S: 0.005-0.04
%, P: 0.008-0.017%, acid-soluble Al
: 0.005-0.100%, N: 0.0010
~0.0070% steel was melted in a vacuum melting furnace and heat treated under various conditions before hot rolling and after hot rolling to change the size of MnS and AlN precipitates. The relationship between the average size of MnS and AlN precipitates determined from a huge number of electron micrographs and the processing rate until breakage occurs during stretch flange forming after DI processing is shown for steel sheets for DI processing manufactured in . The numbers in the figure represent the stretch flanging rate of a sample having a precipitate structure with the average size of MnS and AlN at that point, and the curves represent contour lines of the stretch flanging rate.

As can be seen from Figure 3, the average precipitate size of MnS is 0.
less than 602 μm or more than 0.40 μm, or the average precipitate size of AlN is less than 0.005 μm or 0.20 μm
If it exceeds m, the stretch flange processing rate will deteriorate. Therefore, the average precipitate size of MnS is 0.02 μm or more and 0.40 μm.
m or less, the average precipitate size of AlN(7) is 0.005 p
It is specified as not less than m and not more than 0.20 μm.

Next, the steel components will be explained.

Since C hardens steel, its upper limit is set at 0.0600%. Reducing the amount of C is effective for softening, but
If C is reduced to less than 0.0040%, solid solution C will decrease significantly and BH properties cannot be obtained, so the lower limit is set to 0.0040%. Preferably the range is 0.0040-0.0400%.

Mn needs to be contained in an amount of 0.05% or more in order to prevent hot etching caused by S, but if it exceeds 0.50%, it will harden the steel like C and lose the characteristics of the present invention. The preferred range is 0.10-0.30%.

Al is used as a deoxidizing agent to reduce oxide inclusions that are harmful to workability, and to suppress hardening due to strain aging during surface treatment by fixing N in the steel. It is necessary to contain 0.020%.

However, if it exceeds 0.100%, it will harden the steel and increase surface flaws. The preferred range is 0.030~o,og
o%.

Both P and N are elements that significantly harden steel, and by lowering both P and N, a more remarkable softening effect than previously thought can be obtained. DI specific to the present invention
In order to obtain a steel plate for cans, the upper limit of P is 0.020%, N
The upper limit of is set to 0.0070%.

The preferred range of N is 0.0030% or less.

Moreover, Mn and P have a special interaction regarding stretch flange formability, and even if the content of each is within the above range, the amount of Mn and P may be unbalanced compared to the other amount. It was found that when elongation f = 12- the lunge formability deteriorated. As a result of finding a regression equation through experiments, we found that in order to stably ensure good stretch flange formability, the content of Mn and P should be 10 [P weight %) - 0,03 ≦ [Mn weight %] ≦ 20
The following relationship needs to hold: [P weight %]+0.14.

Especially tensile strength 37kgf/mm” or less, yield point 30kgf
/ mm2 or less, when manufacturing a softer steel plate with excellent DI workability, C: 0.0040-0.0400%,
Mn: 0.10-0.25%, acid-soluble Al: 0
．． 030-0.080%, P: 0.015% or less,
N: Preferably 0.025% or less.

S becomes an inclusion in the steel, and causes surface defects on the steel plate, cracks during processing, stretch flange cracks, and excessive average precipitate size M.
Since it causes nS generation, the upper limit is set to 0.015%.

The steel components in the present invention are as described above, but if necessary, a carbonitride-forming element 0 is added to the steel components of the present invention.
, 0.050% or less of B, and 0.10% or less of Cr. By adding these elements, a steel plate with excellent DI workability can be stably produced.

The hot rolling conditions will be briefly explained. In hot rolling, by specifying the winding temperature and slab heating temperature, it is possible to manufacture a steel plate for DI cans by continuous annealing that is soft and has excellent DI workability, and has appropriate BH properties. If the winding temperature is low, the stretch flange formability will deteriorate and the tensile strength will also increase, so it is set at 600°C or higher. On the other hand, if the temperature is too high, the pickling properties will deteriorate, so the temperature is set at 710°C or lower.

Figure 4 shows C: 0.015-0.040%, Mn 20, 15-0.25%, P: 0.006-0.010.
%, S: 0.004-0.015%, Al: 0
．． 03 to 0.08%, N: 0.004% or less, the relationship between r hot rolling heating temperature - T*J (°C), tensile strength of tin plate, and DI workability is shown.

The manufacturing conditions shown in FIG. 4 are as follows.

Hot rolling finishing temperature: 870 to 910°C Hot rolling winding temperature = 550 to 710°C Cold rolling rate: 87 to 91% Annealing conditions: 7ooc x 30 seconds + 400°C x 60 seconds (-second cooling rate 10 to 40 Temperature rolling: 1.0% plating; electric tin plating In Figure 4, the tensile strength is measured by the tensile strength after electric tin plating, and DI processability is the electric tin plated product board using a laboratory DI forming machine. After performing DI processing, the stretch flange processing rate ((D - Do)/Do) x 100% at the time of pipe expansion was measured.

As shown in Figure 4, the winding temperature is 600 to 710℃.
By doing so, a steel plate having a tensile strength of 42 kgf/mm 2 or less and good stretch flange formability can be obtained regardless of the thermal history before hot rolling and the hot rolling heating temperature. Furthermore, the hot rolling heating temperature T (°C) is T≦6875/(3
,865-log [Al%+0.015) ) -25
0 and the winding temperature is within the range of 600 to 710°C, the tensile strength will be 40 kgf/mm” or less, and the DI
It is possible to produce surface-treated steel sheets with extremely excellent workability.

Figure 5 shows C: 0.01-0.06%, Mn: 0
．． 10-0.40%, P: 0.006-0.020
%, Al: 0.01-0.07%, N knee 15 = 0.001.5-0.0070%, hot rolling heating temperature T-(6875/(3,865-log [Al%
+0.0153) -250) The relationship between the tensile strength of the tin plate, the compressive strength of the DI processed product, and the stretch flange processing rate is shown.

The manufacturing conditions shown in FIG. 5 are as follows.

Hot rolling finishing temperature 2870-910°C Hot rolling winding temperature: 600-710°C Cold rolling rate = 87-91% Annealing conditions: (600-8008C)
500℃) +400℃×(30~500℃) (-cooling rate 10~40℃/sec) Temper rolling = 1.0% Plating: Electric tinting In Figure 5, the tensile strength is the tensile strength after electric tinting. The compressive strength and stretch flanging rate were measured in a laboratory after the DI cans were manufactured. In Figure 5, T - (6875
/(3,865-1og[Al%+0.015))-
250) is approximately 50, 100 and 150, the annealing conditions are varied over a wide range, of which the tensile strength is approximately 40
Only data showing values of kgf/mm2 or less are plotted in the figure. Figure 5 also shows, for comparison, a material manufactured by the conventional box annealing method with a tensile strength of 40 kgf/am.
Data of actual examples showing values of 2 or less are plotted with an X mark.

As can be seen from FIG. 5, the surface-treated steel sheet according to the present invention is softer than the conventional box-annealed material at the stage of being plated, and therefore can be easily subjected to DI processing. Also D
Since the BH effect in the paint baking process after I processing is large, the compressive strength after DI processing is equal to or higher than that of box annealed material. Also, stretch flange formability is superior to box annealed materials.

And the hot rolling heating temperature is T*=6875/(3,865
-log [Al%+0.015]) -250 or less, the highest grade steel plate for DI cans which is the softest and has excellent stretch flange formability can be obtained. Here, hot rolling heating temperature T≦T* However, T* = 6875/(3,865-log [Al
% + 0.0151 > -250 is a significant relationship between steel composition, hot rolling conditions, tinplate tensile strength, DI workability, compressive strength, and average size of MnS and AlN precipitates. This is an experimentally determined equation for the heating temperature. In this case, any heat history before hot rolling can be used, including direct rolling, but especially when manufacturing products with a tensile strength of 40 kgf/mm or less, it is necessary to It is preferable to cool down to this temperature and then heat it to below the above temperature.

Then, it is cold rolled after being descaled by a conventional method and subjected to continuous annealing.

Next, continuous annealing conditions will be explained. Annealing is performed not by the conventional box annealing method but by a continuous annealing method. In the annealing cycle, first, short-time recrystallization annealing is performed for 5 seconds to 3 minutes in a temperature range of recrystallization temperature to 850°C. If the annealing temperature is lower than the recrystallization temperature, the product plate will remain in a cold worked structure and DI processing cannot be performed, so the lower limit of the annealing temperature is set as the recrystallization temperature. In addition, if the annealing temperature exceeds 850°C, the strength of the copper strip during annealing will decrease, making threading operations difficult.
The temperature shall be 50°C. If the annealing time is less than 5 seconds, sufficient grain growth will not occur and the material will become hard, so the lower limit of the annealing time is set to 5 seconds. Furthermore, if the annealing time exceeds 3 minutes, a reduction in the sheet passing speed or a long continuous annealing facility will be required, reducing the industrial value, so the upper limit of the annealing time is set to 3 minutes. The preferred range of annealing temperature is 680 to 750°C. Next, cooling is performed, but if the cooling rate is high, the supersaturated solid solution C before overaging treatment
The amount becomes too large and the driving force for overaging progress becomes large, making it impossible to leave an appropriate amount of solid solution C after overaging treatment, and B
Since H properties cannot be obtained, the upper limit is set to 250°C/sec. If the cooling rate is low, the BH properties will increase for the opposite reason, but the tensile strength of the product sheet will also become hard, so the lower limit is set at 5° C./sec. Next, an overaging treatment is performed at a temperature of 300 to 500°C. If the overaging treatment temperature is lowered, the diffusion rate of C will slow down and the overaging treatment will take a long time, so the lower limit of the overaging treatment temperature should be set at 30°C.
The temperature shall be 0°C. Furthermore, if the overaging temperature is increased, the solid solubility limit of C increases and the steel sheet is hardened, so the upper limit of the overaging temperature is set at 500°C. If the overaging treatment time is short, the overaging treatment will be insufficient and the steel plate will become hard, so the lower limit of the overaging treatment time is set to 30 seconds. Further, if the overaging treatment time is long, the solid solution C after the overaging treatment decreases significantly and BH properties cannot be obtained, so the upper limit of the overaging treatment time is set at 500°C.

Preferred overaging treatment conditions are (350-450°C)
(60×120 seconds).

Then, it is temper rolled in a conventional manner and subjected to a conventional surface treatment.

(Example) Table 1 shows examples of the present invention.

Steel having the components listed in Table 1 was melted in a converter, and the continuously cast steel slab was hot rolled to a thickness of 3.0 mm, pickled, and then cold rolled to a thickness of 0.32 mm. The specimens were annealed under the annealing conditions listed in Table 1, followed by 1.0% temper rolling and electric tinting.

Table 2 shows the total forming energy when the electric tinned steel sheet manufactured in this manner was formed into a DI can using a DI processing machine in a laboratory. The smaller the total molding energy and the less occurrence of galling, the better the DI processability.

Furthermore, the pressure resistance and stretch flange processing rate of the DI cans were measured in a laboratory and the results are also shown in Table 2. It has been found that a stretch flange processing rate of 9.0% or more is evaluated as acceptable by the customer using the measurement method conducted in the laboratory of the present inventors.

As can be seen from Tables 1 and 2, the steel of the present invention has a small total forming energy, no galling, sufficiently high pressure resistance, extremely high stretch flanging rate, and particularly excellent stretch flanging formability. I know that there is.

In addition, the steel of the present invention has not only high pressure strength due to BH hardening, but also
It should be added that since the buckling strength in the vertical direction of the can also increases, the buckling strength is also superior to that of box annealed material if the material strength is the same. Furthermore, since the steel of the present invention has particularly excellent stretch-flange formability, it not only has a low defect rate in stretch-flange forming, but also has the ability to withstand even more severe stretch-flange forming.

-2. (Effects of the invention) The present invention can be manufactured by continuous annealing, so the manufacturing cost is low, the product material has excellent uniformity, and there is no galling.
The present invention provides a steel plate for DI cans that is easy to perform DI processing, has excellent stretch flange formability after DI processing, and has significantly improved pressure resistance by hardening during paint baking after DI processing, and its industrial effects. is enormous.

[Brief explanation of the drawing]

Figure 1 shows the DI produced on the laboratory pilot line.
Figure 2 shows the relationship between the tensile strength of the product plate, the total forming energy in the DI test forming machine, the compressive strength of DI cans that have been painted and baked after forming, and the annealing method for steel sheets for cans. DI manufactured on the pilot line
Figure 3 shows the relationship between the JIS grain size number, the compressive strength of the DI can, the processing rate until breakage occurs during stretch flange forming after DI processing, and the annealing method for steel sheets for cans. Figure 4 shows the relationship between the average size of precipitates, the average size of AlN precipitates, and the processing rate until breakage occurs in stretch flange forming after DI processing. For hot rolling heating temperature T - (6875/(3,865-l
og [Al% + 0.015) ) -250) Figure 5 shows the relationship between the tensile strength of tin plate and DI workability. Spreading heating temperature T-(6875/(3,86
5-log [Al% + 0.015]) -250) is a diagram showing the relationship between the tensile strength of a tin plate, the pressure resistance strength of a DI processed product, and the stretch flanging rate. Figure 1 Tensile strength (kgf/mm) Figure 2 JIS grain size number

Claims (2)

[Claims] (1) C: 0.0040-0.0600% Mn: 0.05-0.50% P: 0.02% or less S: 0.015% or less Acid-soluble Al: 0.020-0 .100% N: 0.0070% or less, provided that 10% is between [Mn weight%] and [P weight%].
A low carbon Al-killed steel piece having the following relationship: P weight %] -0.03 ≦ [Mn weight %] ≦ 20 [P weight %] + 0.14, with the balance consisting of Fe and unavoidable impurities. Rolled between
After winding and cold rolling at a temperature of 600 to 710°C, and then continuous annealing, recrystallization annealing is performed for 5 seconds to 3 hours at a temperature above the recrystallization temperature and below 850°C.
Cooled at a cooling rate of ℃/second, over-aged for 30 to 180 seconds at a temperature of 300 to 500℃, and cooled to 42kgf/mm.
Tensile strength of ^2 or less, grain size number of 8.5 to 11.5,
MnS with an average size of 0.02 μm or more and 0.40 μm or less
and a method for producing a steel sheet for DI cans having an AlN precipitate structure with an average size of 0.005 μm or more and 0.20 μm or less and having excellent stretch flange formability. (2) Weight % C: 0.0040-0.0600% Mn: 0.05-0.50% P: 0.02% or less S: 0.015% or less Acid-soluble Al: 0.020-0. 100% N: 0.0070% or less, however, 10% between [Mn weight%] and [P weight%]
A low carbon Al-killed steel piece having the following relationship: P weight %] - 0.03 ≦ [Mn weight %] ≦ 20 [P weight %] + 0.14, with the balance consisting of Fe and unavoidable impurities. Cool to a temperature below the transformation point, then T*=6875/(3.865-log [Al%+0.
015]) Heated to a temperature T* (°C) or lower that satisfies -250, hot rolled, coiled at a temperature of 600 to 710°C, cold rolled, and then continuously annealed to a temperature higher than the recrystallization temperature of 850°C. After performing recrystallization annealing for 5 seconds to 3 minutes at a temperature below ℃, cooling at a cooling rate of 5 to 250℃/second,
Over-aged for 30 to 180 seconds at a temperature of 0 to 500°C, with a tensile strength of 40 kgf/mm^2 or less, 8.5 to 11
．． Grain size number 5, MnS with an average size of 0.02 μm or more and 0.40 μm or less and 0.005 μm or more and 0.2
A method for producing a steel sheet for DI cans having an AlN precipitate structure with an average size of 0 μm or less and having excellent stretch flange formability.