JP2006107873A - Steel sheet for bottom plate of battery, surface-treated steel sheet for bottom plate of battery, and battery using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-treated steel sheet for a bottom plate excelling in strength, and to provide a bottom plate of a battery and a battery using it. <P>SOLUTION: This steel sheet comprising 0.0-0.60 wt.% of C, 0.80-3.0 wt.% of Si, 0.3-3.0 wt.% of Mn, 0.0-0.06 wt.% of P, 0.0-0.06 wt.% of S, 0.0-0.1 wt.% of Al, 0.0010-0.0150 wt.% of N, the remainder of Fe and inevitable impurities is characterized by including either an iron-nickel alloy layer or a nickel layer as the foremost layer and either an iron-nickel alloy layer or a nickel layer and an iron-nickel alloy layer as its lower layer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a steel plate for a bottom plate of a battery, a surface-treated steel plate for a bottom plate of a battery, and a battery using the same, particularly a steel plate for a bottom plate such as an alkaline manganese battery or a nickel-cadmium battery, a surface-treated steel plate for a bottom plate, and the like. Related to the battery.

  Steel plates for outer cylinders of alkaline manganese batteries and nickel-cadmium batteries are required to have corrosion resistance and workability. Conventionally, plated steel sheets with Ni plating layers or Fe-Ni alloy plating layers are generally used to satisfy them. (For example, see Patent Documents 1 and 2). Battery tubes made of these plated steel sheets are formed by drawing and are made thinner. However, in the case of a bottom plate (sealing plate), an austenitic stainless steel plate or a thick nickel-plated steel plate is used because high strength that can withstand the sealing pressure is required (see, for example, Patent Document 3). The stainless steel plate is excellent in terms of high strength, but has the disadvantages of high contact resistance due to the formation of a strong oxide on the surface and high cost, and the nickel-plated steel plate is usually 0 in order to maintain high strength. It is as thick as 4-0.8mm. For this reason, conventionally, bottom plates such as alkaline manganese batteries and nickel-cadmium batteries have a high strength that can withstand sealing pressure with a small amount of material by reducing the thickness of the plate from the viewpoint of economy, and for batteries. Therefore, a material having corrosion resistance and spot weldability is required.

Patent No. 3292033 publication JP 2004-218043 A JP 2003-263975 A

In order to reduce the thickness of the plate so that it can withstand the sealing pressure with a small amount of material, there is a method of increasing the rolling rate and increasing the strength, and it is used while being plated. However, this method is hard as it is plated, resulting in poor corrosion resistance after processing to the bottom plate or the like. Moreover, since it is still plating, there existed a problem that the range of spot welding was narrow. In order to improve the corrosion resistance and spot weldability, it is effective to perform heat treatment after nickel plating, but there is a problem that the strength of the base material is insufficient when heated.
The present invention has been made in view of these points, and has a strength, corrosion resistance, and spot weldability. The surface-treated steel sheet for a battery bottom plate, the battery-treated bottom plate coated with an ultraviolet curable resin on the surface-treated steel sheet, and It is a technical problem to provide a battery using a bottom plate.

In order to solve the above-mentioned problem, the steel plate for the bottom plate of the battery according to the present invention according to claim 1 is, by weight percent, C: 0.04 to 0.60%, Si: 0.80 to 3.0%, Mn: 0.3 to 3.0%, P: ≦ 0.06%, S ≦ 0.06%, Al: ≦ 0.1%, N: 0.0010 to 0.0150%, balance Fe and inevitable It consists of various impurities. The steel plate for a bottom plate of the present invention can provide a high-strength steel plate that is inexpensive and has a high tempering degree and is optimal for a battery bottom plate by employing the above components.
The surface-treated steel sheet for the bottom plate of the battery according to claim 2 is C: 0.04 to 0.60%, Si: 0.80 to 3.0%, Mn: 0.3 to 3.0% by weight. , P: ≦ 0.06%, S ≦ 0.06%, Al: ≦ 0.1%, N: 0.0010 to 0.0150%, and the outermost layer in the steel sheet composed of the balance Fe and inevitable impurities It has an iron-nickel alloy layer.
The surface-treated steel sheet for the bottom plate of the battery according to claim 3 is, by weight, C: 0.04 to 0.60%, Si: 0.80 to 3.0%, Mn: 0.3 to 3.0%. , P: ≦ 0.06%, S ≦ 0.06%, Al: ≦ 0.1%, N: 0.0010 to 0.0150%, and the outermost layer in the steel sheet composed of the balance Fe and inevitable impurities It has a nickel layer in the outermost layer having an iron-nickel alloy layer and a nickel layer, and an iron-nickel alloy layer in the lower layer.
The surface-treated steel sheet for the bottom plate of the battery according to claim 4 is, by weight, C: 0.04 to 0.60%, Si: 0.80 to 3.0%, Mn: 0.3 to 3.0%. , P: ≦ 0.06%, S ≦ 0.06%, Al: ≦ 0.1%, N: 0.0010 to 0.0150%, and the outermost layer in the steel sheet composed of the balance Fe and inevitable impurities It has a nickel layer and an iron-nickel alloy layer.

  Each surface-treated steel sheet for a bottom plate according to claims 2 to 4 can be obtained by subjecting the steel sheet according to claim 1 to Ni plating and then performing a diffusion treatment by heat treatment. By appropriately controlling the heat treatment temperature and heat treatment time after nickel plating, the surface-treated steel sheet for the bottom plate according to claims 2 to 4 can be obtained, and the diffusion treatment proceeds as the heat treatment temperature is higher and the heat treatment time is longer. A Ni alloy layer is formed. Therefore, the surface-treated steel sheet for bottom plate can be obtained in the order of claim 3, claim 4, and claim 2 by increasing the heat treatment temperature and lengthening the heat treatment time.

  The surface-treated steel sheet for the bottom plate of the battery of the present invention can have a high strength with a tensile strength of 450 MPa or more and an elongation of 15% or more by having the steel components and the surface layer as described above. Surface-treated steel for the bottom plate of the battery thinned to 2 to 0.6 mm can be obtained. And the battery of this invention employ | adopts the above steel plates for baseplates as a baseplate of a battery, and can obtain the battery excellent in corrosion resistance more cheaply.

According to the present invention thus formed, it is possible to obtain a high-quality battery bottom plate that is thin, high-strength, good in corrosion resistance, and has spot weldability, and the bottom plate is thinned to further reduce the material. Can be
Furthermore, since the battery of the present invention has the bottom plate of the battery, it is possible to obtain a battery having a bottom plate of high quality, thin, high strength and low cost.

  Embodiments of the present invention will be described below. As a steel plate used as the base material of the surface-treated steel sheet for the bottom plate of the battery according to the present invention, the weight percentage is C: 0.04 to 0.60%, Si: 0.80 to 3.0%, Mn: 0.3. ~ 3.0%, P: ≤ 0.06%, S ≤ 0.06%, Al: ≤ 0.1%, N: 0.0010 to 0.0150%, balance Fe and unavoidable impurities Are preferably used. The significance of the chemical component is as follows.

Since C has a high tempering degree on the original plate, C is preferably 0.04% or more. On the other hand, if the C component exceeds 0.60%, the amount of precipitated carbide increases and the workability of the original sheet decreases, and at the same time, the load of cold rolling increases, the shape deteriorates, and the plateability in the continuous annealing process is inhibited Etc., causing a decrease in productivity. Therefore, in the present invention, the upper limit value of the C component is set to 0.60%.
Si has a large solid solution strengthening ability in steel and is an effective element for obtaining high strength. Therefore, 0.8% or more is necessary. Further, the higher the material strengthening surface, the better. However, the upper limit is set to 3.0% in order to increase the cold rolling load and deteriorate the shape.

  Mn is a component necessary for preventing red heat embrittlement during hot rolling due to the impurity S, and at the same time, in the same way as C, in order to give a high tempering degree to the original plate, the Mn component is 0.3% or more And However, as is the case with C here, too much load of cold rolling, crack generation during slab rolling, deterioration of shape, threadability hindrance in continuous annealing process, etc., cause productivity reduction, The upper limit is set to 3.0%.

  P is a crystal grain refining component and is added at a certain ratio because it increases the strength of the original plate, but it inhibits corrosion resistance. In the present invention, when P exceeds 0.06%, the corrosion resistance, particularly the hole resistance, is remarkably lowered, so the upper limit is made 0.06%.

  S is an impurity component that causes red hot brittleness during hot rolling, and it is desirable that it be as small as possible. However, it cannot completely prevent contamination from steel stones, and it is difficult to desulfurize during the process. Unavoidable. Since red heat brittleness due to a small amount of residual S can be reduced by Mn, the upper limit value of the S component is set to 0.06%.

  Al is added to the steel bath as a deoxidizer during steelmaking. However, when it becomes 0.10% or more, it is an oxidation inhibitor at the time of continuous casting and a mold powder used as an anti-seizure agent for the mold in continuous casting. Oxygen and excess Al react to inhibit the original powder effect. Therefore, the Al content is 0.10% or less.

  N, like C and Mn, gives a high degree of tempering to the original plate. Although it is a necessary component for strengthening the yield strength, if it is less than 0.001%, it causes difficulty in steelmaking, while addition over 0.0150% reduces the yield of ferronitride added during steelmaking. And is not stable, and at the same time, the anisotropy during press molding is significantly deteriorated. Further, since cracks are generated on the surface of the continuous cast piece, resulting in casting defects, the N component range is set to 0.001 to 0.0160% in the present invention.

The steel sheet (slab serving as a base material) having the above chemical components is subjected to hot rolling, winding, primary cold rolling, nickel plating, annealing (diffusion treatment after plating), and the intended battery A surface-treated steel sheet for bottom plate is obtained. Or you may make it heat-process (diffusion process) through secondary cold rolling and temper rolling, without annealing immediately after nickel plating. Each of these steps is performed as follows.
Hot rolling Although the slab heating temperature in a hot rolling process is not specified in this invention, it is desirable to set it as 1100 degreeC or more from the viewpoint of ensuring stable hot finishing rolling temperature. If the hot rolling finish temperature is ₃ points or less, the crystal structure of the hot steel strip is mixed and coarsened, and the desired strength cannot be obtained. Therefore, the hot rolling finish temperature is ₃ points or more. Is desirable.

  The coiling temperature is not specified in the present invention, but the coiling temperature is preferably 700 ° C. or lower in order to suppress the coarsening of crystal grains.

Primary cold rolling The steel sheet hot-rolled in the above component system is subjected to primary cold rolling, and this cold rolling rate is an important strength factor of the present invention together with the components, in order to obtain the desired strength. 50-90%.

Nickel plating The material subjected to 50 to 90% primary cold rolling as described above is subjected to nickel plating before the next annealing. Further, it may be carried out after annealing or secondary cold rolling, which is a subsequent process, but in this case, in order to form an iron-nickel alloy layer after nickel plating, it is necessary to further carry out a diffusion treatment by heat treatment. If the nickel layer remains on the outermost layer by the diffusion treatment after the Ni plating, the nickel becomes soft and is in a desirable state when subjected to subsequent processing. Nickel plating was performed by matte nickel plating, bright nickel plating, or iron-nickel alloy plating after the above steel plate was subjected to alkaline electrolytic degreasing, water washing, sulfuric acid immersion, and pretreatment after water washing by a conventional method. When performing iron-nickel plating, it is more preferable to perform nickel or nickel-based alloy plating as the lower layer. When performing nickel plating, as a method for obtaining an iron-nickel alloy layer, the well-known Watt bath or sulfamic acid bath is used, and the bright nickel plating produced by adding a brightening agent to the plating bath. And may be obtained by heat treatment. The thickness of the nickel plating layer is preferably in the range of 0.5 to 7 μm. More preferably, the range of 1 to 4 μm is good.
Moreover, you may obtain from the iron-nickel alloy plating produced by adding iron to a nickel plating bath. In this case, the thickness of the iron-nickel plating layer may be at least 0.1 μm or more. Even if it is thick, there is no problem in the characteristics, but if it is too thick, it is uneconomical. Economically, it may be 7 μm or less.

Annealing 50 to 90% cold-rolled material as described above, after degreasing in the cleaning process or after nickel plating, continuous annealing at 680 ° C or higher, or batch annealing at 500 ° C or higher Annealing. The annealing after the nickel plating also serves as a diffusion treatment of Ni. By annealing, Ni diffuses into Fe and an iron-nickel alloy layer is formed. In particular, by adjusting the annealing temperature, alloying of the surface layer after nickel plating can be controlled, and by annealing the annealing temperature at a relatively low temperature, for example, by continuous annealing, the nickel layer on the surface and the lower layer on the surface An Fe-Ni alloy layer can be formed, and by annealing at a temperature higher than that, a nickel layer and an Fe-Ni alloy layer are formed on the outermost layer, and by further raising the annealing temperature, the entire outermost layer iron-nickel alloy A layer is formed. Therefore, when heat treatment is not performed in the subsequent process, the annealing temperature is controlled as described above so that the entire surface is formed on the outermost layer, the iron-nickel alloy layer is formed, or the nickel layer is partially or entirely left on the outermost layer. To do.

Secondary cold rolling When the secondary cold rolling rate after annealing increases, the strength increases and is desirable. However, the elongation decreases and the corrosion resistance deteriorates. Therefore, when secondary cold rolling is performed, the strength is 7% or less. . Then, if necessary, surface roughness is imparted by temper rolling.

Heat treatment When heat treatment (annealing) after nickel plating is not performed, heat treatment is performed after secondary cold rolling. As the heat treatment, either the box annealing method or the continuous annealing method can be applied. In this case, it is preferable in terms of corrosion resistance to have a soft nickel layer as the outermost layer, but it is not economically preferable if it is too thick. An entire surface, an iron-nickel alloy layer or a nickel layer may be formed on the outermost layer, or an iron-nickel alloy layer and a nickel layer may be mixed.
By passing through the above processes, it is possible to obtain a surface-treated steel sheet for a bottom plate of a battery excellent in high strength and workability having a tensile strength of 450 MPa or more and an elongation of 15% or more. The surface-treated steel sheet for the bottom plate is not particularly limited, but has a high strength, so that it can be made thinner than the conventional battery bottom plate, and a range of 0.2 to 0.6 mm can be suitably selected.

  The present invention will be further specifically described with reference to the following examples.

Using the hot rolled steel having the chemical components shown in Table 1, primary cold rolling, nickel plating, annealing, and some of them were subjected to secondary cold rolling, temper rolling, and the like. Table 1 shows the steel components of Examples and Comparative Examples and the conditions in each step.
Nickel plating was performed by ordinary methods such as alkaline electrolytic degreasing, water washing, sulfuric acid immersion, and pretreatment after water washing, followed by normal matte nickel plating or semi-bright nickel plating. In addition, two-layer plating was performed, with matte nickel plating or semi-gloss plating as the lower layer and bright nickel plating as the upper layer.

1) Matte nickel plating Matte nickel plating was performed using the following nickel sulfate bath.
Bath composition nickel sulfate _{(NiSO 4 · 6H 2 O)} 300g / L
Nickel chloride _{(NiCl 2 · 6H 2 O)} 45g / L
Boric acid (H ₃ BO ₃ ) 30 g / L
Bath pH: 4 (adjusted with sulfuric acid)
Stirring: Air stirring Bath temperature: 60 ° C
The anode uses S pellets (trade name, manufactured by INCO, spherical) loaded in a titanium basket and covered with a polypropylene bag.

2) Semi-bright nickel plating Semi-bright nickel plating was performed using the following nickel sulfate bath.
Bath composition nickel sulfate _{(NiSO 4 · 6H 2 O)} 300g / L
Nickel chloride _{(NiCl 2 · 6H 2 O)} 45g / L
Boric acid (H ₃ BO ₃ ) 30 g / L
Polyoxyethylene adduct of unsaturated alcohol 3.0g / L
Unsaturated carboxylic acid formaldehyde 3.0g / L
Bath pH: 4 (adjusted with sulfuric acid)
Stirring: Air stirring Bath temperature: 60 ° C
3) Bright nickel plating Bright nickel plating was performed by appropriately adding saccharin as a brightening agent to a nickel sulfate bath.
Bath composition nickel sulfate _{(NiSO 4 · 6H 2 O)} 300g / L
Nickel chloride _{(NiCl 2 · 6H 2 O)} 45g / L
Boric acid (H ₃ BO ₃ ) 30 g / L
Saccharin 3.0 g / L
Bath pH: 4 (adjusted with sulfuric acid)
Stirring: Air stirring Bath temperature: 60 ° C
The anode uses S pellets (trade name, manufactured by INCO, spherical) loaded in a titanium basket and covered with a polypropylene bag.

  In Examples 1 to 8, matte nickel plating and semi-gloss plating were performed at 1.0 to 5.0 μm. In Comparative Examples 1 to 6 and 8, matte plating or semi-gloss plating was performed by 2.0 μm, and in Comparative Example 7 semi-gloss 1.0 μm, followed by gloss plating by 1.0 μm to form a two-layer plating. In Comparative Examples 9 and 10, matte plating was performed at 1.0 μm on the base, followed by 1.0 μm gloss plating. In Examples 1-2 and Comparative Example 6, hot-rolled steel sheets were processed in the order of primary cold rolling, nickel plating, annealing, and secondary cold rolling. About Examples 3-4, Examples 6-9, and Comparative Examples 1-3, the hot-rolled steel plate was processed in order of primary cold rolling, nickel plating, annealing, and temper rolling. In Comparative Examples 4, 7, and 10, the hot-rolled steel sheet was processed in the order of primary cold rolling, annealing, secondary cold rolling, nickel plating, and temper rolling. Example 5 and Comparative Examples 5 and 8 were processed in the order of primary cold rolling, annealing, temper rolling, nickel plating, annealing, and temper rolling. In Comparative Example 9, temper rolling was performed instead of secondary cold rolling in Comparative Example 10.

The characteristics of the test materials are evaluated by the following test methods, and the evaluation results are shown in Table 2.
(Mechanical properties)
The mechanical properties were evaluated by measuring the tensile strength (indicated by TS and MPa) and elongation (indicated by T.EL and%) by cutting the specimen into a JIS No. 5 specimen size. A TS of 450 MPa or more (indicated by a circle in the table) is considered good. El was 15% or more (indicated by a circle in the table) as good. The case where the above numerical values were not satisfied was represented as x (failure). The acceptable range (indicated by “表” in the table). In the comprehensive evaluation, TS is 450 MPa or more and T.I. El is 15% or more of the acceptable range (indicated by “◎” in the table).
(Corrosion resistance)
A right-angle bending process was performed, and the test was performed for 30 days by a constant temperature and humidity test method (60 ° C. × 90% RH). The case where rust was generated was determined to be rejected (indicated by x in the table).
If the mechanical properties and corrosion resistance are excellent, it can be used practically as a high-strength application, so it was accepted as a comprehensive evaluation.

In addition, this invention is not limited to the said embodiment and Example, It can change as needed. Although the conventional plate thickness is as thick as 0.4 to 0.8 mm, in the embodiment, the plate thickness can be as thin as 0.2 to 0.6 mm.
In Comparative Examples 1 and 7-9, the amount of C is outside the proper range, in Comparative Examples 2, 8-10, the amount of Si is outside the proper range, and in Comparative Examples 3, 8, 10 the Mn amount is in the proper range. Since it was outside, the overall evaluation was bad. Comparative Example 4 was poor in overall evaluation because there was no diffusion treatment after nickel plating and the secondary rolling rate was high. In Comparative Example 5, the annealing temperature was low and the overall evaluation was bad. Since Comparative Example 6 had a high secondary rolling rate, the overall evaluation was poor.

  The surface-treated steel sheet for the bottom plate of the battery of the present invention is excellent in mechanical properties such as high strength and workability, can be thinned, and has excellent corrosion resistance, thereby reducing the manufacturing cost of the bottom plate of the battery and the battery. It is possible to provide a high-quality battery, and the industrial applicability is high as a battery bottom plate of an alkaline manganese battery, a nickel-cadmium battery or the like.

Claims (7)

  % By weight, C: 0.04 to 0.60%, Si: 0.80 to 3.0%, Mn: 0.3 to 3.0%, P: ≤ 0.06%, S ≤ 0.06 %, Al: ≦ 0.1%, N: 0.0010 to 0.0150%, the balance Fe and unavoidable impurities.   % By weight, C: 0.04 to 0.60%, Si: 0.80 to 3.0%, Mn: 0.3 to 3.0%, P: ≤ 0.06%, S ≤ 0.06 %, Al: ≦ 0.1%, N: 0.0010 to 0.0150%, a steel sheet comprising the balance Fe and inevitable impurities, and having an iron-nickel alloy layer as the outermost layer Surface-treated steel sheet for bottom plate.   % By weight, C: 0.04 to 0.60%, Si: 0.80 to 3.0%, Mn: 0.3 to 3.0%, P: ≤ 0.06%, S ≤ 0.06 %, Al: ≦ 0.1%, N: 0.0010 to 0.0150%, balance Fe and inevitable impurities, steel layer having nickel layer as the outermost layer and iron-nickel alloy layer below it A surface-treated steel sheet for a battery bottom plate.   % By weight, C: 0.04 to 0.60%, Si: 0.80 to 3.0%, Mn: 0.3 to 3.0%, P: ≤ 0.06%, S ≤ 0.06 %, Al: ≦ 0.1%, N: 0.0010 to 0.0150%, balance Fe and unavoidable impurities, steel sheet having nickel layer and iron-nickel alloy layer as outermost layer Surface-treated steel sheet for battery bottom plate.   The surface-treated steel sheet for a battery bottom plate according to any one of claims 1 to 4, having a tensile strength of 450 MPa or more and an elongation of 15% or more.   The surface-treated steel sheet for a battery bottom plate according to claim 5, wherein the plate thickness is 0.2 to 0.6 mm.   A battery comprising the bottom plate of the battery according to claim 1.