JP2011058036A - Steel sheet for drawn can, and plated steel sheet for drawn can - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steel sheet for a drawn can which has satisfactory earring properties, secures sealing properties at the sealing part of a can lid and has extremely excellent surface quality after drawing, and to provide a plated steel sheet for a drawn can which has the above earring properties, has the above surface quality, and also has excellent soundness of a plating layer after drawing. <P>SOLUTION: The steel sheet for a drawn can extremely having excellent surface quality after drawing has a composition comprising, by mass, 0.0035 to 0.0080% C, ≤0.35% Si, ≤1.0% Mn, ≤0.030% P, ≤0.025% S, 0.003 to 0.100% solAl, ≤0.010% N and ≤0.040% Nb, and also satisfying (3 to 6)x C%, and the balance Fe with inevitable impurities, and is characterized in that Δr value satisfies +0.15 to -0.15, the average r value satisfies 1.00 to 1.35, the GS of recrystallized grains satisfies no: 11.0 to 13.0, and earring ratio satisfies ≤2.5%. The plated steel sheet for the can is also provided. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

 The present invention relates to a steel plate for drawn cans and a plated steel plate for drawn cans, and more specifically, not only good earring properties, but also sealability of the can lid sealing portion (surface roughness after drawing), which is a very important quality of battery cans and the like. Extremely excellent surface quality after drawing, which ensures the degree of roughness (abnormality of dents and abnormal dents and wrinkles) (abnormality caused by uneven shearing during drawing) Steel sheet for drawing cans with the surface quality without any dents and wrinkles) and the above-mentioned surface quality, and the corrosion resistance of the plating layer (the soundness such as the presence or absence of cracking of the plating layer is greatly affected) The present invention provides a plated steel sheet for drawn cans that is excellent in the soundness of the plating layer.

  The steel plate for drawn cans is a cold-rolled steel plate or a plated steel plate with various plating such as Sn plating, Ni plating, Ni diffusion plating, Cr plating, etc., severe multistage drawing, DI (Drawn & Ironed) processing Can be made into a can container such as a battery can (hereinafter simply referred to as a squeeze can), or a can container that has been subjected to various plating or coating such as Sn plating, Ni plating, Cr plating, etc. It becomes.

 As a conventional technique, a steel plate having better earring characteristics is required, as in the technique disclosed in the following Patent Document 1 or the technique introduced in the following Non-Patent Document 1, and a steel sheet that satisfies such a requirement. Has come to be supplied. However, in applications such as battery cans, the surface quality after drawing is extremely excellent to ensure the sealing performance of the sealing part of the top lid (surface roughness is small and abnormal due to uneven shearing during drawing. Steel plate for drawn cans having a surface texture without any dents and wrinkles) and a plate for drawn cans with excellent surface soundness, excellent corrosion resistance and good corrosion resistance after drawing. There has been a demand for providing steel sheets.

Japanese Patent Publication No. 7-59734 Japanese Patent No. 3996754

Sheet Metal Press Molding Subcommittee 29th SMF Seminar Materials "The Latest Trends in Can-making Technology and Can-making Materials (October 7, 1994 / at Nagoya University)"

  The problem to be solved by the present invention is that the surface quality after drawing is excellent (the surface roughness is small and the irregularity during drawing) has good earring properties and ensures the sealability of the can lid sealing part. A steel plate for drawn cans having an abnormal dent due to uniform shearing and a surface property without wrinkles) and a drawn can having the above-mentioned earring properties and the above-mentioned surface quality and excellent in the soundness of the plated layer after drawing. It is to provide a plated steel sheet.

The present inventors have intensively studied to provide a steel sheet that solves the above-mentioned problems, and have completed the present invention. The gist of the present invention is as follows.
(1) By mass%, C: 0.0035 to 0.0080%, Si: ≦ 0.35%, Mn: ≦ 1.0%, P: ≦ 0.030%, S: ≦ 0.025%, solAl: 0.003 to 0.100%, N: ≦ 0.0100%, Nb: ≦ 0.040% and (3-6) × C%, the balance being Fe and inevitable elements, Δr value: +0.15 to -0.15, average r value: 1.00 to 1.35, GS.no of recrystallized grains: 11.0 to 13.0, earring rate: 2.5% or less Steel sheet for drawn cans with excellent surface quality after drawing.
(2) Furthermore, it is characterized by excellent aging characteristics by adding B and Ti in the range of [N − {(14/11) B + (14/48) Ti} ≧ 0 ppm] by mass%. The steel plate for drawn cans according to (1).
(3) Since at least one surface of the steel plate for drawn cans according to (1) or (2) is plated with any one of Sn plating, Ni plating, Ni diffusion plating, and Cr plating, Plated steel sheet for drawn cans characterized by excellent plating layer integrity.

 The steel sheet of the present invention has a problem that the present invention intends to solve, “the surface quality after drawing, which has excellent earring properties and ensures the sealing performance of the can lid sealing portion (the surface roughness unevenness is small). Steel sheet for drawing cans having abnormal dents due to non-uniform shearing during drawing and surface characteristics without wrinkles) and the earring property and surface quality of the plated layer after drawing. In addition, it is possible to sufficiently provide a plated steel sheet for a drawing can that is excellent in industrial use, and has a remarkable industrially useful effect.

 The present invention is described in detail below.

 In the non-patent document 1, FIG. 4 also shows that the present inventors can obtain a good earring property by setting the Δr value to almost zero. Focusing on the fact that the earrings vary greatly even when the Δr value is zero, as indicated by the fact that the earrings cannot be reduced to 1% or less, as well as the large variation of ~ 3%. A method for making it even more excellent has been studied, and Patent No. 3996754 of the above-mentioned Patent Document 2 has been invented and put into practical use, where average r value = {r value (L) + r value (C) + 2r value (X) } / 4, Δr value = {r value (L) + r value (C)} / 2−r value (X), r value (L): r value in rolling direction (L direction), r value (C): R value in the direction perpendicular to the rolling direction (C direction), r value (X): rolling direction and 45 ° C. direction ( It is an r-value of direction).

  The inventors of the present invention have been well-received for their excellent earring characteristics in the practical use of the steel sheet of Patent No. 3996754, but as a steel sheet for battery cans, not only earring properties but also more important. It was found that new characteristics were necessary.

 In other words, an important evaluation item for battery can performance is “sealability of the sealing part (the degree of leakage of electrolyte, gas, etc. from the gap between the surface irregularity of the inner surface of the battery can sealing part and the sealing material (nylon, etc.) "When the irregularity on the inner surface of the can is large, the gap between the sealing material such as nylon is not large, the sealing performance is poor, and when the irregularity on the inner surface of the can is small, the sealing performance is good." The “corrosion resistance (namely, the soundness of the plating layer) of the plated layer of the battery can or the like” was determined not only to the press molding conditions but also to the fact that the steel plate characteristics had a great influence.

 One characteristic of the steel sheet is that the crystal grains of the steel sheet are extremely fine, and the fine grain level is finer than GS.no = 8.8 to 10.8 shown in Example Table 2 of Patent No. 3996754. GS.no = 11.0-13.0 and ultra-fine grains, and average r value of 1.0 to 1.35 and low r value are essential. I found out. In addition, GS.no was measured by the cutting method of JIS G 0552 (b).

 As a result of various investigations on the sealing performance of the sealing portion of the battery can manufactured by the multistage press, the present inventors are naturally expected to improve by reducing the crystal grain size, As a result of various investigation tests, in the case of a drawn can of about 1 to 2 stages, the range of GS.no = 8.8 to 10.8 shown in Table 2 of the embodiment of the above-mentioned Japanese Patent No. 3996754, particularly 10 to 10. Although the surface roughness can be remarkably improved in the range of 8 (the degree of unevenness of the surface roughness), it has reached a level that remarkably improves the sealability although it is improved by the 5 to 10 stage drawing normally performed in battery cans and the like. I found that there was no.

 Therefore, further refinement effect was examined, and it was found that the refinement effect becomes prominent even in multi-stage press when GS.no is 11.0 or more and 12.0 level. However, it has also been found that it does not reach a level that can ensure a better sealing performance as intended by the present inventors.

 The present inventors have further studied various causes of hindering the sealing performance, and have found the following results.

 The sealing performance of the multi-stage press can, that is, the surface roughness of the inner surface of the can body of the can sealing part, in addition to the factor that affects the size of the crystal grains, the average r value is high as in the above-mentioned Japanese Patent No. 3996754 And the shear strain enters at a pitch about 10 times larger than the unevenness (waviness) pitch of the surface roughness of the rough skin part, the part is greatly recessed more than the surface roughness (unevenness), and sometimes the recesses are wrinkled. As a result, it was found that the sealing performance was greatly hindered.

 Further, the Ni diffusion plating in which the Ni plating layer is annealed and softened and the ductility is good at the site where the shear strain enters at a pitch about 10 times larger than the unevenness (undulation) pitch of the rough surface portion It was also found out that even in a steel plate, the Ni plating layer was broken to impair the soundness of the Ni plating layer and greatly inhibit the corrosion resistance.

 And it is also found that the larger the average r value is, the larger the dent or crease and the Ni plating layer are broken, and the average r value of the method of the present invention is 1.0 to 1.35. I was able to find a way to do it.

 In normal molding, cracks occur when the average r value is low, and the higher the r value, the better (formability) workability can be obtained. As a result of considering whether local shear strain in the thickness direction enters and severe roughness occurs, a steel plate with a high average r value has a high (111) crystal orientation of the steel plate, and thus the steel plate has a high (111) crystal orientation. It has been found that a high average r-value is obtained because it is difficult for the twist to occur.

 However, in the latter stage of the press process in multi-stage drawing, even after severe work hardening has occurred at the die shoulder R and wrinkle holding shoulder R, further severe bending and bending at the die shoulder R and wrinkle holding shoulder R occurs. The high average r-value steel sheet that does not have the iron crystal twisting system in the thickness direction when subjected to reversing processing does not have the iron crystal twisting system in the normal sheet thickness direction. As a result of being forced to bend in the direction, local shearing in the thickness direction is caused, causing abnormal dents and wrinkles, greatly impairing the sealability and corrosion resistance of the Ni plating layer. I think that.

 In the following, detailed description of the configuration conditions of the present invention will be given.

  If C is less than 0.0035% by mass, GS.no: 11.0 or more cannot be refined, and if the C content exceeds 0.0080% by mass, the Nb content necessary for non-aging is not sufficient. It is necessary to exceed 0.040 mass%, and since the average r value exceeds 1.35 due to the increase in Nb and the characteristics of the present invention cannot be obtained, the C content needs to be 0.0035 to 0.0080 mass%. is there.

 If Si is increased, it adversely affects plating adhesion and coating adhesion when it is applied after canning, so it is necessary to regulate it to 0.35% by mass or less.

 If Mn is contained in a large amount, it becomes hard and cannot withstand severe deep drawing, so it is necessary to regulate it to 1.0% by mass or less.

  P increases the strength of the steel sheet and may be added as necessary. However, if it exceeds 0.030% by mass, the secondary workability of the drawn can (the deep drawn can is, for example, −10 ° C. At such a low temperature, the end of the can side wall may be brittlely ruptured due to impact during dropping or bending distortion, and an index indicating the ease of occurrence of such rupture is called secondary workability.) It is necessary to regulate to 0.030 mass% or less. Moreover, in order to improve secondary workability more, it is good to regulate P content to 0.010 mass% or less.

  S inhibits brittleness during hot rolling and causes rough ears in the hot-rolled steel strip, so it is necessary to regulate it to 0.025% by mass or less.

  solAl is an element necessary for obtaining good surface quality when making a slab, and it is necessary to contain 0.003% by mass or more, and if it exceeds 0.100% by mass, this effect is saturated. Not only will the cost be increased, but there will also be an adverse effect of excessive hardening due to solid solution strengthening, so it is necessary to regulate it to 0.100% by mass or less.

  N is combined with Nb and Al in the composition of the present invention, and can prevent harmful effects such as aging deterioration of the material due to N. However, since the harmful effects are caused when the amount is too much, 0.0100% by mass or less It is necessary to regulate.

  Nb contains a large amount of C as compared with the ultra-low carbon steel, and is substantially non-aged as NbC-based precipitates, and for ultrafine-graining of crystal grains due to these precipitates (3 × C mass%) It is necessary to add more than this, but if the amount of Nb added exceeds (6 × C mass%) or exceeds 0.040 mass%, the average r value will exceed 1.4 and good skin roughness resistance will not be obtained. Must be regulated to Nb: (3-6) × C mass% and 0.040 mass% or less.

 Since B and Ti are elements that inhibit the excellent earring characteristics of the steel of the present invention, it is preferable not to add them, but for applications that require excellent non-aging properties, B and Ti are preferably used in mass%. May be added in the range of [N − {(14/11) B + (14/48) Ti} ≧ 0 ppm]. If B is added excessively, the earring characteristics deteriorate, and if Ti is added excessively, the crystal grain size becomes large and it becomes difficult to obtain the desired fine particles of the present application, so it is necessary to regulate.

 And the balance must be the steel composition which consists of Fe and an unavoidable element. In addition, Cu, Ni, Cr, Sn, etc. mixed in scrap recycling, etc. are less than about 0.5, 0.5, 0.3, 0.05% by mass, respectively, so there is no significant effect on the characteristics. It doesn't matter.

 An example of manufacturing conditions for the steel sheet of the present invention will be described below.

 The steelmaking conditions for the steel plate for a drawing can of the present invention are not particularly limited as long as the steel having the above-described composition can be melted into a slab, and the slab may be formed by a normal method.

 The hot rolling condition is an important process for making the crystal grain of the steel plate for the drawn can a predetermined one, but no special regulation is required and normal manufacturing conditions may be used. Specifically, the cast slab may be heated to 1000 ° C. or higher, finish rolled at 850 ° C. to 950 ° C., cooled after finish rolling, and made into a wound hot rolled steel strip. Note that if the finish rolling temperature deviates from the normal hot rolling conditions and becomes less than 850 ° C., it becomes α zone rolling, and the hot rolled sheet texture differs from the normal one, and as a result, the aggregate after cold rolling and recrystallization annealing. The tissue also becomes abnormal, abnormal skin roughness called ridging occurs, and earring properties deteriorate.

 Further, the coiling temperature for hot rolling may be 350 to 670 ° C., which is a normal coiling temperature, without particular restriction.

 The rolling ratio of the cold rolling is as follows. Using the hot rolled sheet manufactured under the manufacturing conditions of the present invention, the cold rolling ratio is changed in advance to produce a cold rolled steel sheet or a plated steel sheet for a drawing can. It is necessary to determine the relationship with the value and to set the cold rolling rate so that the Δr value of the steel sheet becomes substantially zero (in the range of +0.15 to −0.15). The range of the cold rolling rate at which excellent earring properties can be obtained is 84 to 88%.

  The recrystallization annealing does not need to be regulated in particular and may be completed, but if it is too high, the crystal grain size and the average r value will exceed the range of the present invention, so it is necessary not to be too high. There is. As the annealing method, recrystallization annealing is preferably performed by a continuous annealing method in which fine grains are easily obtained.

  The temper rolling is usually performed by temper rolling of about 0.5 to 3.0%, and the shape is excellent, and if the tempering degree is selected, a steel plate for a drawn can having an appropriate yield point can be obtained. .

  The surface treatment of the steel sheet is not particularly limited as long as the surface of the produced cold-rolled steel sheet is subjected to Ni plating, Ni diffusion plating, Sn plating, Cr plating, or the like, if necessary. The Ni diffusion plated steel sheet described in (3) above can be manufactured by performing Ni plating heat treatment on the surface of the cold rolled steel sheet manufactured as described above and then performing Ni diffusion heat treatment. In addition, after cold rolling, pre-treatment such as degreasing is performed, and then Ni electroplating is performed. Then, continuous annealing is performed that combines recrystallization annealing, recrystallization softening annealing of Ni plating layer, and diffusion heat treatment. Can be manufactured efficiently. The Ni diffusion plated steel sheet according to (3) manufactured by this method is not only workability and adhesion of the plating layer but also severe due to a synergistic effect with the action and effect of the plating base plate according to (1). Even during multi-stage pressing, it is possible to prevent “cracking, folding wrinkles, scraping of the Ni plating layer on the rough surface of the Ni diffusion plating layer”, etc., and to improve the soundness of the Ni plating layer and to provide a battery drawn can with excellent corrosion resistance. it can. In addition, when Ni plating thickness is 5 micrometers or less, the soundness improvement effect of Ni plating layer is remarkable.

 The effects of the present invention will be described below with reference to examples.

  A slab of the components shown in Table 1 is made, and hot-rolled sheets are manufactured under the hot rolling conditions shown in Table 2 (heating temperature / SRT (° C.), finishing temperature / FT (° C.), winding temperature / CT (° C.)). And cold rolling at a cold rolling rate (CR (%)) at which the previously investigated Δr value is almost zero, and the conditions shown in Table 2 (Ni plating thickness (μm), annealing temperature / ST (° C.), Manufactures 0.25mm steel plate for drawn cans, specifically Ni diffusion plated steel plate for drawn cans and cold-rolled steel plate for drawn cans with soaking time / t (sec), temper rolling ratio / SP (%)) The average r value, GS.no, and earring rate {Earring rate of cylindrical drawn can = (mount height of can side wall Max−valley height Min) / average can height × 100} were evaluated. The evaluation results are shown in Table 2. The earring rate was evaluated by preparing a drawn cup with a blank diameter = φ41.0 mm and a punch diameter = φ20.65 mm, and measuring the earring rate according to the above definition. It should be noted that the absolute value of the earring rate changes depending on the cup drawing condition. In addition, the average value which measured 360 degree | times for the average can height = can wall height about 0.8 degree pitch is shown.

 In addition, the roughness of the skin, the sealing property, and the soundness of the Ni plating layer were evaluated by taking a photograph of the cross-sectional structure of the plate thickness at 90% of the height of the can from the bottom of the prototype can. did.

 The roughness of the skin is evaluated based on the degree of roughness of the surface roughness of the cross section, and is divided into three stages, where very large irregularities are generated / conventional level (XX), which is improved, but large irregularities are not present. The results are shown in Table 2 after being classified and evaluated as being satisfactory (×), greatly improved and having slight unevenness and good (◯).

 Sealability is evaluated based on the degree of abnormal dents and wrinkles caused by uneven shearing with a surface line length of 1000 μm, and is divided into three stages, resulting in very large abnormal dents and large wrinkles. / Conventional level (XX), improved but abnormal dents and folds are not enough (X), greatly improved and no abnormal dents and folds (○) The results are shown in Table 2.

 The soundness of the Ni plating layer is evaluated based on whether or not the Ni plating layer is cracked. Each evaluation is divided into three stages, where very large cracks are generated / conventional level (xx), and improved. The results are shown in Table 2 after being classified and evaluated as those with insufficient cracks (x) and those with significant improvements and no cracks (O).

 Test steels A, B, and C are steels of the composition of the conventional steel, steel A is B = 0.0003 mass%, C = 0.020 mass% Ti-added ultra-low carbon steel, steel B is B = 0.0003 wt% contained C = 0.0020 wt% Nb-Ti added ultra low carbon steel, Steel C is a low carbon steel whose C content exceeds the range of the present invention and Nb and Ti are not added .

 Test steels D, E, F, and G are steels within the range of the present invention. Steel D has a composition of C = 0.040 mass%, Nb = 0.015 mass%, Nb / C = 3.75, steel E is a composition of C = 0.050 mass%, Nb = 0.020 mass%, Nb / C = 4.00, Steel F is C = 0.0065 mass%, Nb = 0.032 mass%, Nb / C = Steel composition according to (1), steel G is C = 0.0048 mass%, Nb = 0.020 mass%, Nb / C = 4.17 composition, N = 0 .0035% by mass, Ti = 0.008% by mass, and B = 0.0005% by mass.

 Sample steels H, I, and J are comparative examples of the present invention. Steel H has a composition of C = 0.040 mass%, Nb = 0.010 mass%, Nb / C = 1.54, Steel I Is C = 0.0100 mass%, Nb = 0.050 mass%, composition of Nb / C = 5.00, Steel J is C = 0.0038 mass%, Nb = 0.050 mass%, Nb / C = 13.20 steel with a composition.

 Samples Nos. 1, 2, 4, 10, 11, and 12 are conventional examples or comparative examples in which the steel components are out of the scope of the present invention, and the average r value and GS.no are outside the scope of the present invention. The rough skin, the sealing property, and the soundness of the Ni plating layer are also poor and greatly deviated from the target of the present invention.

 Sample 3 is a conventional example in which Ni plating is not applied under the steel B component and the steel plate manufacturing conditions of sample 2, and the same material characteristics as sample 2, and the roughness of the can and the sealing performance greatly deviate from the targets of the present invention. Yes.

 Samples Nos. 5, 6, 8, and 9 were batteries that were cold-rolled, plated with 2 μm of Ni by electroplating on the steel sheet, then subjected to recrystallization annealing, softening recrystallization of Ni, and diffusion alloying treatment, and temper rolling. In the examples of the present invention of Ni diffusion plated steel sheets manufactured for cans, the average r value and GS.no are within the scope of the present invention, and the skin roughness of the cans, the sealing properties and the soundness of the Ni plating layer are also excellent. And achieve the goal of the present invention. Sample No. 9 is an example described in the above (2) having a steel composition in which Ti and B are added to prevent N aging, and has excellent aging characteristics that are more stable without impairing excellent battery can characteristics. Obtained.

 Sample No. 7 is an example of producing a container plate or cold-rolled steel sheet that was annealed without being subjected to Ni plating after cold rolling. Similarly, the average r value and GS.no are within the scope of the present invention. The can's rough skin and sealing properties are also excellent, achieving the object of the invention.

 As is clear from the results of the above examples, the steel plate of the present invention is a very excellent aperture that has a good earring property and ensures the sealing performance of the can lid sealing portion, which is a problem to be solved by the present invention. Steel plate for drawn cans with surface quality after processing (surface roughness is small, surface properties without abnormal dents and wrinkles due to non-uniform shearing during drawing), earrings, and surface quality And providing a plated steel sheet for drawn cans that is excellent in the soundness of the plated layer after drawing ”can be sufficiently achieved.

  In addition, the steel plate for drawing cans of the present invention as a plating plate for containers or a cold-rolled steel plate is subjected to severe multi-stage deep drawing after various plating such as Sn plating, Ni plating, Ni diffusion plating, Cr plating, etc. Processing, strict DI processing, can be made into deep-drawn cans, or after plating, various platings such as Sn plating, Ni plating, Cr plating, etc. are applied, and used for various can containers including battery cans The effect can be demonstrated.

Claims (3)

 In mass%, C: 0.0035 to 0.0080%, Si: ≦ 0.35%, Mn: ≦ 1.0%, P: ≦ 0.030%, S: ≦ 0.025%, solAl: 0 0.003 to 0.100%, N: ≦ 0.0100%, Nb: ≦ 0.040% and (3-6) × C%, the balance being Fe and inevitable elements, Δr value: +0.15 -0.15, average r value: 1.00-1.35, recrystallized grain GS.no: 11.0-13.0, earring rate: 2.5% or less Steel plate for drawn cans with excellent surface quality after processing.  Furthermore, the aging characteristics are excellent by adding B and Ti in the range of [N-{(14/11) B + (14/48) Ti} ≧ 0 ppm] by mass%. 1. A steel plate for a drawing can according to 1. The steel sheet for drawing cans according to claim 1 or claim 2, wherein any one of Sn plating, Ni plating, Ni diffusion plating, and Cr plating is applied to at least one surface of the drawn layer. Plated steel sheet for drawn cans characterized by excellent soundness.