TW202100759A - Steel sheet for can, and method for manufacturing same - Google Patents

Abstract

Provided are a steel sheet for a can, suitable as a can container material used in a food or beverage can, and a method for manufacturing the steel sheet for a can. This steel sheet for a can has a component composition containing, in terms of mass%, 0.010-0.080% C, no more than 0.05% Si, 0.10-0.70% Mn, no more than 0.03% P, no more than 0.020% S, 0.005-0.020% Al, and 0.0120-0.0180% N, the remainder being Fe and unavoidable impurities, and the steel sheet for a can has a [Delta]r of -0.3-0.3.

Description

Steel plate for tank and manufacturing method thereof

The present invention relates to a can steel plate suitable for can container materials used for food or beverage cans and a manufacturing method thereof. The present invention particularly relates to a steel plate for cans that is better for lug caps and screw caps for deep drawing (Draw and Redraw, DRD) cans and bottle caps, and Production method.

Among the steel plates used in beverage cans and food cans, steel plates called Double Reduced (DR) materials are sometimes used for can lids, can bottoms, and three-piece can bodies. The DR material refers to a steel sheet manufactured by performing annealing after primary cold rolling, and then performing secondary cold rolling at a rolling rate of more than a certain level. Compared with single-reduced (SR) material that only performs temper rolling (temper rolling) with a small rolling rate, it can be hardened and thinned easily. From the viewpoints of reducing environmental load and cost reduction in recent years, it is required to reduce the amount of steel plates used in beverage cans or food cans, and there is an increasing demand for DR materials that can easily achieve thinning of steel plates.

DR materials are hardened mainly by work hardening, and therefore generally have low drawing formability. Therefore, there is a problem that defects such as cracks occur in the rivet portion of the Easy-Open End (EOE) and the flange processing of the three-piece can body portion that requires high drawing formability. In this regard, a steel sheet with improved drawing formability has been proposed.

For example, Patent Document 1 discloses a steel sheet for high-strength containers containing C: 0.01% to 0.05%, Si: 0.04% or less, Mn: 0.1% to 1.2%, S: 0.10% or less, and Al ：0.001%～0.100%, N: 0.10% or less, P: 0.0020%～0.100%, the remainder contains Fe and inevitable impurities, the tensile strength TS is 500 MPa or more, and the endurance in the width direction and the rolling direction The difference is 20 MPa or less.

In addition, for example, Patent Document 2 discloses a high-strength steel sheet characterized by containing C: 0.010% or more and 0.080% or less, Si: 0.05% or less, and Mn: 0.10% or more and 0.70% or less in mass%. P: 0.03% or less, S: 0.020% or less, Al: 0.005% or more and 0.070% or less, N: 0.0120% or more and 0.0180% or less, and the remainder contains Fe and unavoidable impurities. In the above-mentioned N, the N content as solid solution N is 0.0100% or more, the average particle size of ferrite is 7.0 μm or less, and the dislocation density at 1/4 depth of the plate thickness from the surface is 4.0×10 ¹⁴ m ^-2 or more and 2.0×10 ¹⁵ m ^-2 or less, the tensile strength in the rolling direction perpendicular to the aging treatment is 530 MPa or more, and the elongation is 7% or more. [Prior Art Document] [Patent Document]

Patent Document 1: WO2009/125876 Patent Document 2: WO2015/166646

[The problem to be solved by the invention] In the technique described in Patent Document 1, good flange workability and necking workability are obtained, but the drawing formability required for processing into DRD cans, screw caps, etc., is insufficient. For example, when drawing a steel plate into a can body, it is desirable that the protrusion amount (flange width) of the flange portion after forming is uniform in the circumferential direction of the can body. There is a demand for a steel sheet for cans that has small circumferential fluctuations in the flange width and is excellent in deep drawing formability. In addition, the technique described in Patent Document 1 has a tensile strength of about 640 MPa, and the strength of the steel sheet is insufficient for a thin-walled product to have sufficient compressive strength.

Similarly, in the technique described in Patent Document 2, the drawing formability is also insufficient.

The present invention has been made in view of the foregoing circumstances, and its object is to provide a high-strength steel sheet for cans having excellent draw formability and a method of manufacturing the same. Here, high strength means that the tensile strength in the rolling direction after aging treatment is 650 MPa or more.

The inventors of the present invention made diligent studies to solve the above-mentioned problems. As a result, the inventors of the present invention focused on the influence of the in-plane anisotropy Δr of the r-value of the steel sheet on the drawing formability of the steel sheet for cans and obtained new findings, that is, if the Δr of the steel sheet is -0.3 Above and 0.3 or less, excellent drawing formability can be obtained. In addition, the inventors of the present invention found that by setting the steel composition, slab heating, hot rolling, coiling, primary cold rolling, annealing, and secondary cold rolling conditions within a predetermined range, it is possible to provide a Δr of -0.3 Steel plate for cans of above and below 0.3. And based on this knowledge, this invention was completed. In addition, in this specification, the "r value" refers to a Lankford value that represents a plastic strain ratio. In addition, in this specification, "Δr" can be calculated in accordance with the equation described later. [Means to solve the problem]

The present invention is based on the above findings, and its gist is as follows. (1) A steel plate for cans, with mass%, containing C: 0.010% or more and 0.080% or less, Si: 0.05% or less, Mn: 0.10% or more and 0.70% or less, P: 0.03% or less, S: 0.020% or less, Al: 0.005% or more and 0.020% or less, And N: 0.0120% or more and 0.0180% or less, and The remainder is the composition of Fe and inevitable impurities, The in-plane anisotropy Δr of the r value is -0.3 or more and 0.3 or less.

(2) The steel sheet for cans as described in (1) above, in which in addition to the component composition, it also contains in mass %, Ti: 0.005% or more and 0.020% or less, Nb: 0.005% or more and 0.020% or less, Mo: 0.01% or more and 0.05% or less, Cr: 0.04% or more and 0.10% or less, B: 0.0005% or more and 0.0060% or less, Ca: 0.0010% or more and 0.01% or less, Ni: 0.05% or more and 0.15% or less, and Cu: 0.05% or more and 0.20% or less More than one of them.

(3) A method for manufacturing a steel plate for cans, including the steps of heating a slab having the composition described in (1) or (2) above to 1180°C; and finishing the heated slab The step of performing hot rolling at a temperature above 820°C; the step of winding the hot-rolled hot-rolled sheet at a temperature exceeding 640°C and below 700°C; and performing a primary cooling on the coiled hot-rolled sheet at a rolling rate of over 85% The step of rolling; the step of annealing the cold-rolled cold-rolled sheet at a temperature above 620°C and below 690°C; and the step of cold-rolling the annealed sheet at a rolling rate of more than 20% and less than 40% step. [Effects of the invention]

According to the present invention, it is possible to provide a high-strength steel sheet for cans that has an r-value in-plane anisotropy Δr of -0.3 or more and 0.3 or less, and excellent deep drawability. By using the steel plate for cans of the present invention, a thin DR steel plate can be used to make cans or lids, which can achieve resource saving and cost reduction, and exhibit significant industrial effects.

Hereinafter, the present invention will be described in detail. The steel sheet for cans of the present invention is characterized in that: With mass%, containing C: 0.010% or more and 0.080% or less, Si: 0.05% or less, Mn: 0.10% or more and 0.70% or less, P: 0.03% or less, S: 0.020% or less, Al: 0.005% or more and 0.020% or less, And N: 0.0120% or more and 0.0180% or less, and The remainder is the composition of Fe and inevitable impurities, The in-plane anisotropy Δr of the r value is -0.3 or more and 0.3 or less. Furthermore, the steel sheet for cans of the present invention can be manufactured by heating a slab having the above-mentioned composition to 1180°C or higher, and then hot rolling at a finishing temperature of 820°C or higher, and then at a temperature exceeding 640°C and 700°C. Hereinafter, winding is performed, primary cold rolling is performed at a rolling rate of 85% or more, annealing is performed at 620° C. or higher and 690° C. or less, and secondary cold rolling is performed at a rolling rate of more than 20% and 40% or less.

First, the component composition of the steel sheet for cans of the present invention will be described. C: 0.010% or more and 0.080% or less C is an important element for improving the strength, and by making it 0.010% or more, it contributes to achieving high strength. Specifically, the tensile strength in the rolling direction after the aging treatment is 650 MPa or more. The preferred amount of C is 0.020% or more. On the other hand, if the C content exceeds 0.080%, the in-plane anisotropy Δr of the r value is less than -0.3, and the drawing formability is reduced. Therefore, the upper limit of the C content needs to be 0.080% or less. The preferable amount of C is 0.040% or less.

Si: 0.05% or less If Si is added in a large amount, the surface of Si will be concentrated, the surface treatment properties will be deteriorated, and the corrosion resistance will be reduced. Therefore, the amount of Si needs to be 0.05% or less, preferably 0.03% or less. On the other hand, Si contributes to the improvement of tensile strength, so the lower limit of Si is preferably set to 0.01%.

Mn: 0.10% or more and 0.70% or less Mn has the effect of improving the tensile strength of the steel sheet by solid solution strengthening, and the effect of preventing the decrease in hot ductility due to S contained in the steel by forming MnS. In order to obtain this effect, it is necessary to add 0.10% or more of Mn. In particular, from the viewpoint of increasing the strength of the steel sheet, it is preferable to add 0.20% or more of Mn, and more preferably 0.50% or more. On the other hand, if Mn exceeds 0.70%, the in-plane anisotropy deteriorates. Therefore, the amount of Mn is set to 0.70% or less. Preferably, the amount of Mn is 0.65% or less.

P: Below 0.03% If P is added in a large amount, it becomes excessively hardened and P segregates in the center of the steel sheet, thereby reducing the drawing formability and also reducing the corrosion resistance. Therefore, the upper limit of the amount of P is set to 0.03%. Preferably, the amount of P is 0.02% or less. Furthermore, reducing the amount of P to less than 0.01% will be accompanied by an increase in costs such as smelting costs. Therefore, from the viewpoint of economy, it is preferable to set the amount of P to 0.01% or more.

S: 0.020% or less S forms sulfides in steel, reduces hot ductility, and reduces workability in hot rolling. Therefore, the upper limit of the amount of S is made 0.020% or less. Preferably, the amount of S is 0.015% or less. Furthermore, if the S content is 0.008% or more, pitting corrosion can be prevented regardless of the contents of the tank, so the S content is preferably 0.008% or more.

Al: 0.005% or more and 0.020% or less Al is an element added as a deoxidizer. In order to obtain this effect, it is necessary to add 0.005% or more of Al. When Al is present in excess in the steel, it combines with N to form AlN, which reduces the solid solution N in the steel, and as a result, the tensile strength of the steel sheet decreases. Therefore, the amount of Al needs to be 0.020% or less. The amount of Al is preferably 0.008% to 0.019%, more preferably 0.011% to 0.016%. The amount of Al is preferably 0.008% or more, more preferably 0.011% or more, and preferably 0.019% or less, and more preferably 0.016% or less.

N: 0.0120% or more and 0.0180% or less As a solid solution strengthening element, N contributes to increasing the strength of the steel sheet. For this effect, it is necessary to add 0.0120% or more as the amount of N. On the other hand, if a large amount of N is added, the in-plane anisotropy Δr of the r value is significantly reduced, and the drawing formability is reduced, so the upper limit of the amount of N is made 0.0180%. Preferably, the amount of N is 0.0135% to 0.0165%. The amount of N is preferably 0.0135% or more, and more preferably 0.0165% or less. The steel sheet for a can of the present invention contains the above-mentioned components, and the remainder is Fe and unavoidable impurities as its basic components.

If necessary, in addition to the basic components, the steel plate for cans of the present invention may also contain Ti: 0.005% or more and 0.020% or less, Nb: 0.005% or more and 0.020% or less, Mo: 0.01% or more and 0.05% or less, Cr: 0.04% or more and 0.10% or less, B: 0.0005% or more and 0.0060% or less, Ca: 0.0010% or more and 0.01% or less, Ni: 0.05% or more and 0.15% or less, and Cu: 0.05% or more and 0.20% or less More than one of them.

Ti: 0.005% or more and 0.020% or less As a precipitation strengthening element, Ti contributes to the increase in strength of the steel sheet. For this effect, it is preferable to add 0.005% or more of Ti. On the other hand, if Ti is added in a large amount, the anisotropy of the steel sheet becomes too large, so the amount of Ti is preferably set to 0.020% or less.

Nb: 0.005% or more and 0.020% or less Nb, as a precipitation strengthening element, contributes to the increase in strength of the steel sheet. For this effect, it is preferable to add 0.005% or more of Nb. On the other hand, if Nb is added in a large amount, the anisotropy of the steel sheet becomes too large, so it is preferably 0.02% or less.

Mo: 0.01% or more and 0.05% or less Mo functions as a precipitation strengthening element, and by making the structure finer, it contributes to high strength of the steel sheet. For this effect, it is preferable to add 0.01% or more of Mo. However, even if Mo is added in a large amount, the effect is saturated, so the amount of Mo is preferably set to 0.05% or less.

Cr: 0.04% or more and 0.10% or less As a precipitation strengthening element, Cr contributes to the increase in strength of the steel sheet. For this effect, it is preferable to add 0.04% or more of Cr. When Cr is added in a large amount, it becomes a coarse precipitate and the effect of increasing the strength is saturated. Therefore, the amount of Cr is preferably set to 0.10% or less.

B: 0.0005% or more and 0.0060% or less B contributes to the increase in strength of the steel plate by refining it. For this effect, it is preferable to add 0.0005% or more of B. Even if B is added in a large amount, the effect is saturated, and the absolute value of the in-plane anisotropy Δr of the r value of the steel sheet becomes larger, so the amount of B is preferably set to 0.0060% or less.

Ca: 0.0010% or more and 0.01% or less Ca has the effect of making sulfides finer and improving hot ductility. In addition, Ca has the effect of reducing the amount of Mn forming the compound MnS due to the combination of Ca and S, and increasing the ratio of the amount of Mn that contributes to solid solution strengthening, thereby contributing to the increase in strength of the steel sheet. Therefore, it is preferable to add 0.0010% or more of Ca. Even if Ca is added in a large amount, the effect is saturated, and it may become a coarse inclusion and deteriorate the drawing formability. Therefore, the amount of Ca is preferably set to 0.01% or less.

Ni: 0.05% or more and 0.15% or less Ni contributes to the enhancement of the strength of the steel sheet by solid solution strengthening and fine graining. For this effect, it is preferable to add 0.05% or more of Ni. When a large amount of Ni is added, the deterioration of the surface properties becomes remarkable, so the amount of Ni is preferably set to 0.15% or less.

Cu: 0.05% or more and 0.20% or less Cu contributes to the enhancement of the strength of the steel sheet by solid solution strengthening and granulation. For this effect, it is preferable to add 0.05% or more of Cu. In the case of adding a large amount, the deterioration of the surface properties becomes significant, so the amount of Cu is preferably set to 0.20% or less, more preferably set to 0.15% or less.

Next, the material properties of the steel sheet for cans of the present invention will be described. In-plane anisotropy of r value Δr: -0.3 or more and less than 0.3 In order to form DRD cans or caps on the basis of good drawing formability, Δr, which is an index of in-plane anisotropy of r value, needs to be -0.3 or more and 0.3 or less. Here, Δr is expressed by the formula of Δr=(r ₀ +r ₉₀ -2·r ₄₅ )/2. The more Δr deviates from the above range, the greater the anisotropy of the r value, and the larger the so-called "ears" of the flange portion at the time of deep drawing, so that a good shape cannot be obtained. That is, if Δr deviates from the above range, the variation in the width of the flange portion after deep drawing becomes large, and therefore, normal deep drawing with a uniform flange width shape cannot be achieved in the steel plate for cans. Δr is preferably -0.25 or more and 0.25 or less.

Tensile strength in rolling direction after aging treatment: 650 MPa or more In order to ensure the compressive strength of the DRD can body or bottle cap, it is preferable that the tensile strength of the steel sheet in the rolling direction be 650 MPa or more. By setting the tensile strength to 650 MPa or more, sufficient compressive strength can be ensured even if the steel plate is thinned. In the case of the DR material, the tensile strength in the rolling direction is generally lower than that in the rolling direction. Therefore, the tensile strength in the rolling direction is evaluated in this specification. In addition, many steel sheets for cans are used after burn-in coating. Therefore, in this specification, the evaluation is based on the characteristics after aging treatment at 210°C for 10 min, which is equivalent to burn-in coating. When making the sheet thickness particularly thin, it is preferable to make the tensile strength of the steel sheet in the rolling direction of 680 MPa or more. On the other hand, in the case of excessively increasing the strength, the occurrence of forming defects such as wrinkles during forming becomes significant, so it is preferable to make the tensile strength 800 MPa or less.

Next, the manufacturing method of the steel plate for cans of this invention is demonstrated. The steel sheet for cans of the present invention can be manufactured through the following steps: a step of heating a slab with the composition to 1180°C or higher; a step of hot rolling the heated slab at a finishing temperature of 820°C or higher; The hot-rolled hot-rolled sheet is coiled at a temperature exceeding 640°C and 700°C or less; the coiled hot-rolled sheet is subjected to a cold rolling step with a rolling rate of 85% or more; The step of annealing the rolled sheet at 620° C. or higher and 690° C. or lower; and the step of performing secondary cold rolling on the annealed sheet with a rolling rate exceeding 20% and 40% or less.

Heating temperature: above 1180℃ If the heating temperature of the slab before hot rolling is too low, part of AlN is not melted, the amount of solid solution N decreases, and the tensile strength decreases. Therefore, in the step of heating the slab, a heating temperature of 1180°C or higher is required. The preferred heating temperature is 1200°C or higher. The upper limit of the heating temperature is not particularly specified, but if it is 1300°C or lower, surface defects caused by scale are easily avoided, so the upper limit is preferably set to 1300°C.

Finishing temperature: above 820℃ If the finishing temperature in the hot rolling step is less than 820°C, the Δr becomes a value outside the predetermined range, and the drawing formability deteriorates. Therefore, the finishing temperature needs to be 820°C or higher. The preferred finishing temperature is 860°C or higher. The upper limit of the finishing temperature is not particularly limited, but if it is 930°C or less, a steel sheet with a finer grain size can be obtained, which is preferable.

Winding temperature: over 640℃ and below 700℃ When the winding temperature in the winding step is 640°C or lower, the formation of cementite in the steel is insufficient, and the first cold rolling of the next step is performed in a state where solid solution C is excessive, so the Δr If the value is outside the specified range, the drawing formability deteriorates. Therefore, the winding temperature needs to exceed 640°C. The preferred winding temperature is 650°C or higher. On the other hand, if the winding temperature exceeds 700°C, the grain size of the hot-rolled sheet becomes coarse, so the grain size of the final steel sheet also becomes coarse, and the tensile strength decreases. Therefore, the winding temperature needs to be 700°C or lower. The preferred winding temperature is 680°C or less.

Here, before cold rolling, pickling may be performed as needed. Furthermore, the pickling conditions are not specifically defined, as long as the surface rust of the hot-rolled sheet can be removed. Therefore, as long as the pickling is carried out according to the conventional method.

One-time cold rolling rate: over 85% In order to refine the grain size of the ferrous iron after annealing and increase the tensile strength, the rolling rate in the primary cold rolling step needs to be 85% or more. The rolling rate is preferably 86% or more. On the other hand, if the rolling ratio is 91.4% or less, the Δr can be easily controlled to be small, which is preferable. It is more preferable to set the total cold rolling ratio obtained by the total rolling ratio of the primary cold rolling and the secondary cold rolling described later to 90.5% or less, and more preferably to 90.0% or less.

Annealing temperature: above 620℃ and below 690℃ In order to ensure the drawing formability, sufficient recrystallization is required during annealing. For this reason, in the step of annealing the cold rolled plate obtained in the primary cold rolling step, the annealing temperature needs to be 620°C or higher. On the other hand, if the annealing temperature is too high, the grain iron particle size will be coarsened and the tensile strength will decrease. Therefore, the annealing temperature needs to be 690°C or lower. The annealing temperature is preferably 640°C or higher, preferably 680°C or lower, and more preferably 640°C to 680°C. Furthermore, the annealing time is preferably set to 10 s or more. In addition, the annealing method is not limited, and it is preferable to use the continuous annealing method from the viewpoint of the uniformity of the material. Furthermore, the cooling conditions after annealing are not particularly limited. From the viewpoint of increasing the strength due to the action of solid solution C, it is more preferable to set 50°C/s in the temperature range of 500°C to 300°C after annealing. The above cooling rate performs cooling.

Secondary cold rolling rate: more than 20% and less than 40% The annealed sheet obtained after the annealing is increased in strength by secondary cold rolling, and is finished into a thin steel sheet. In order to make the tensile strength of the steel sheet after the aging treatment in the rolling direction of 650 MPa or more, the rolling rate in the secondary cold rolling step needs to be more than 20%. The preferable rolling rate is 22% or more. On the other hand, if the secondary cold rolling rate is too high, the drawing formability deteriorates. Therefore, the rolling rate needs to be 40% or less. In particular, when high drawing formability is required, it is preferable to set the rolling ratio to 35% or less.

Through the above, the steel sheet for cans of the present invention is obtained. Even if the steel sheet obtained here is subjected to surface treatment such as plating or chemical conversion treatment, the effect of the invention will not be lost. [Example]

The steel containing the components of the steel symbols A to V shown in Table 1 and the remainder containing inevitable impurities and Fe was smelted to obtain a steel slab. The obtained steel slabs were heated under the conditions shown in Table 2, followed by hot rolling, coiling, pickling to remove the scale, cold rolling once, and annealing at each annealing temperature in a continuous annealing furnace. The obtained annealed sheets were subjected to secondary cold rolling at each secondary cold rolling rate to obtain steel sheets with a thickness of 0.12 mm to 0.22 mm (steel plates 1 to 29).

[Table 1] Steel symbol C Si Mn P S Al N other Remarks A 0.032 0.01 0.25 0.011 0.011 0.016 0.0151 - Invention Examples B 0.020 0.02 0.30 0.014 0.012 0.016 0.0139 - Invention Examples C 0.039 0.01 0.14 0.009 0.013 0.010 0.0163 - Invention Examples D 0.040 0.01 0.50 0.013 0.010 0.018 0.0121 - Invention Examples E 0.026 0.01 0.70 0.009 0.008 0.008 0.0175 - Invention Examples F 0.080 0.01 0.38 0.010 0.009 0.019 0.0136 - Invention Examples G 0.012 0.01 0.23 0.013 0.010 0.014 0.0152 - Invention Examples H 0.046 0.01 0.24 0.014 0.011 0.016 0.0136 - Invention Examples I 0.023 0.01 0.63 0.014 0.009 0.018 0.0157 - Invention Examples J 0.033 0.01 0.52 0.011 0.010 0.016 0.0158 - Invention Examples K 0.084 0.01 0.36 0.013 0.012 0.014 0.0142 - Comparative example L 0.005 0.01 0.23 0.014 0.011 0.015 0.0147 - Comparative example M 0.033 0.01 0.23 0.008 0.012 0.013 0.0191 - Comparative example N 0.035 0.01 0.36 0.010 0.008 0.080 0.0032 - Comparative example O 0.032 0.01 0.23 0.012 0.011 0.018 0.0156 Ti: 0.009 Invention Examples P 0.035 0.01 0.23 0.016 0.011 0.014 0.0150 Nb: 0.014 Invention Examples Q 0.029 0.01 0.25 0.016 0.013 0.016 0.0147 Mo: 0.03 Invention Examples R 0.030 0.01 0.25 0.012 0.012 0.019 0.0153 Cr: 0.08 Invention Examples S 0.033 0.01 0.25 0.013 0.010 0.009 0.0142 B: 0.0024 Invention Examples T 0.030 0.01 0.33 0.015 0.012 0.015 0.0161 Ca: 0.0034 Invention Examples U 0.028 0.01 0.31 0.019 0.010 0.016 0.0155 Ni: 0.09 Invention Examples V 0.034 0.01 0.30 0.011 0.011 0.017 0.0141 Cu: 0.11 Invention Examples (quality%)

[Table 2] Steel plate symbol Steel symbol Heating temperature (℃) Finishing temperature (℃) Winding temperature (℃) Hot rolled thickness (mm) One-time cold rolling rate (%) Annealing temperature (℃) Cooling rate (℃/s) Secondary cold rolling rate (%) Board thickness (mm) Total cold rolling rate (%) Remarks 1 A 1230 870 650 1.9 87.9 650 110 twenty two 0.18 90.5 Invention Examples 2 B 1230 920 680 2.0 86.7 620 100 25 0.20 90.0 Invention Examples 3 C 1200 900 670 1.9 85.4 670 110 35 0.18 90.5 Invention Examples 4 D 1180 820 660 2.0 85.0 650 90 30 0.21 89.5 Invention Examples 5 E 1260 860 660 1.6 86.1 640 120 28 0.16 90.0 Invention Examples 6 F 1250 900 650 2.0 92.2 690 150 twenty three 0.12 94.0 Invention Examples 7 A 1230 870 650 1.9 87.9 650 40 twenty two 0.18 90.5 Invention Examples 8 A 1220 790 650 1.6 86.7 650 110 25 0.16 90.0 Comparative example 9 B 1220 860 670 1.8 86.7 530 90 25 0.18 90.0 Comparative example 10 B 1210 900 650 1.9 81.1 630 100 50 0.18 90.5 Comparative example 11 G 1190 880 660 1.6 86.0 680 120 twenty four 0.17 89.4 Invention Examples 12 H 1200 900 650 1.6 85.7 650 120 30 0.16 90.0 Invention Examples 13 I 1230 910 650 1.8 85.7 660 120 30 0.18 90.0 Invention Examples 14 J 1220 880 650 1.5 86.3 650 115 27 0.15 90.0 Invention Examples 15 K 1250 860 670 1.8 86.8 680 90 twenty four 0.18 90.0 Comparative example 16 L 1200 870 670 1.5 86.8 650 120 twenty four 0.15 90.0 Comparative example 17 M 1230 850 680 2.0 83.8 660 100 35 0.21 89.5 Comparative example 18 N 1260 860 680 1.5 88.0 650 130 twenty two 0.14 90.7 Comparative example 19 O 1240 880 660 1.8 85.4 650 110 twenty four 0.20 88.9 Invention Examples 20 P 1240 880 660 1.8 85.4 650 110 twenty four 0.20 88.9 Invention Examples twenty one Q 1240 880 660 1.8 85.4 650 110 twenty four 0.20 88.9 Invention Examples twenty two R 1240 880 660 1.8 85.4 650 110 twenty four 0.20 88.9 Invention Examples twenty three S 1240 880 660 1.8 85.4 650 110 twenty four 0.20 88.9 Invention Examples twenty four T 1240 880 660 1.8 85.4 650 110 twenty four 0.20 88.9 Invention Examples 25 U 1240 880 660 1.8 85.4 650 110 twenty four 0.20 88.9 Invention Examples 26 V 1240 880 660 1.8 85.4 650 110 twenty four 0.20 88.9 Invention Examples 27 A 1230 870 630 1.9 87.9 650 110 twenty two 0.18 90.5 Comparative example 28 G 1230 930 690 1.6 85.0 670 110 25 0.18 88.8 Invention Examples 29 L 1240 920 680 1.7 85.3 700 110 28 0.18 89.4 Comparative example

Tensile strength in rolling direction after aging treatment After an aging treatment equivalent to burn-in coating at 210°C for 10 minutes, a tensile test No. 5 specified by the Japanese Industrial Standards (JIS) Z 2241 was taken with the tensile direction as the rolling direction. According to JIS Z2241, the tensile strength was evaluated.

In-plane anisotropy of r value Δr The in-plane anisotropy Δr of the r value was measured and evaluated by the natural vibration method (module r) described in the American Society for Testing Material (ASTM) A623M.

Drawing formability From the obtained steel plate, a blank was punched with a diameter of 160 mm, and then formed by drawing and then drawing to form a can body with a diameter of 82.8 mm and a height of 45.5 mm. Furthermore, the bottom of the tank is processed with bead diameters of 70 mm and 40 mm (depth 0.5 mm, curvature radius 1 mm). With respect to the obtained can body, the flange width was measured at an interval of 15 degrees over the entire circumference. If the difference between the maximum value and the minimum value of the flange width is 1.5 mm or less, the drawing formability is considered to be good and evaluated as ◎, if it exceeds 1.5 mm and less than 2 mm, the drawing formability is considered acceptable and evaluated It is ○, and if it exceeds 2 mm, it is regarded as poor in deep drawing formability and evaluated as ×. The detailed conditions of this test are described below. Lubrication conditions: apply lubricant on both sides of the steel plate The drawing ratio of the first drawing: 1.52 The drawing ratio of the second drawing: 1.26 Wrinkle suppression pressure in each drawing: 0.3 MPa The shoulder radius of the mold during the first drawing: 2.5 mm The shoulder radius of the mold during the second drawing: 2.5 mm

Compressive strength Tighten the lid of the can body, open a hole from the lid side and send air under the seal, and measure the buckling pressure at the bottom of the can. If it is 0.18 MPa or more, it is evaluated as ○, and if it is less than 0.18 MPa, it is evaluated as × .

The test results are shown in Table 3. In all the examples of the present invention, the in-plane anisotropy Δr of the r value is -0.3 or more and 0.3 or less, and the drawing formability and compressive strength are excellent. On the other hand, in the comparative example, any one of the above-mentioned characteristics is inferior.

[table 3] Steel plate symbol Steel symbol Tensile strength (MPa) Δr Deep drawing formability※1 Compressive strength※2 Remarks 1 A 710 -0.18 ◎ ○ Invention Examples 2 B 725 -0.06 ◎ ○ Invention Examples 3 C 800 -0.21 ◎ ○ Invention Examples 4 D 780 -0.12 ◎ ○ Invention Examples 5 E 770 -0.10 ◎ ○ Invention Examples 6 F 760 -0.30 ○ ○ Invention Examples 7 A 660 -0.23 ◎ ○ Invention Examples 8 A 720 -0.42 × ○ Comparative example 9 B 730 -0.53 × ○ Comparative example 10 B 840 -0.56 × ○ Comparative example 11 G 700 0.16 ◎ ○ Invention Examples 12 H 750 -0.22 ◎ ○ Invention Examples 13 I 760 -0.26 ○ ○ Invention Examples 14 J 720 -0.24 ◎ ○ Invention Examples 15 K 750 -0.59 × ○ Comparative example 16 L 590 0.41 × × Comparative example 17 M 810 -0.44 × ○ Comparative example 18 N 640 -0.25 ◎ × Comparative example 19 O 740 -0.16 ◎ ○ Invention Examples 20 P 746 -0.17 ◎ ○ Invention Examples twenty one Q 737 -0.11 ◎ ○ Invention Examples twenty two R 735 -0.12 ◎ ○ Invention Examples twenty three S 731 -0.24 ◎ ○ Invention Examples twenty four T 730 -0.09 ◎ ○ Invention Examples 25 U 734 -0.14 ◎ ○ Invention Examples 26 V 738 -0.18 ◎ ○ Invention Examples 27 A 732 -0.31 × ○ Comparative example 28 G 695 0.30 ○ ○ Invention Examples 29 L 592 0.32 × × Comparative example ※1 Drawing formability ◎: 1.5 mm or less ○: More than 1.5 mm and 2.0 mm or less ×: more than 2.0 mm ※2 Compressive strength ○: 0.18 MPa or more ×: less than 0.18 MPa

no

no

Claims (3)

A steel plate for cans, with mass%, containing C: 0.010% or more and 0.080% or less, Si: 0.05% or less, Mn: 0.10% or more and 0.70% or less, P: 0.03% or less, S: 0.020% or less, Al: 0.005% or more and 0.020% or less, And N: 0.0120% or more and 0.0180% or less, and The remainder is the composition of Fe and inevitable impurities, The in-plane anisotropy Δr of the r value is -0.3 or more and 0.3 or less. The steel plate for cans according to claim 1, which, in addition to the composition, also contains in mass%, Ti: 0.005% or more and 0.020% or less, Nb: 0.005% or more and 0.020% or less, Mo: 0.01% or more and 0.05% or less, Cr: 0.04% or more and 0.10% or less, B: 0.0005% or more and 0.0060% or less, Ca: 0.0010% or more and 0.01% or less, Ni: 0.05% or more and 0.15% or less, and Cu: 0.05% or more and 0.20% or less More than one of them. A manufacturing method of steel plate for tanks, including: The step of heating the slab with the composition described in claim 1 or claim 2 to 1180°C or higher; The step of performing hot rolling on the heated slab at a finishing temperature of 820°C or higher; The step of winding the hot-rolled hot-rolled sheet at a temperature exceeding 640°C and below 700°C; Performing a cold rolling step on the coiled hot-rolled sheet at a rolling rate of over 85%; The step of annealing the cold-rolled sheet once cold-rolled at a temperature above 620°C and below 690°C; and The annealed annealed sheet is subjected to a secondary cold rolling step with a rolling rate exceeding 20% and 40% or less.