JP2002129377A - Method for manufacturing sn-ni alloy plated stainless steel-sheet with low contact resistance and superior surface luster - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a Sn-Ni alloy plated stainless steel-sheet which presents a preferable luster, and which shows a low contact resistance even after exposed in an atmosphere of high temperature and high humidity for a long time. SOLUTION: This method includes employing a ferritic stainless steel sheet or an austenitic stainless steel sheet with surface roughness of 0.050 μm or less by Ra (a unit of average surface roughness defined in JIS), as a base sheet to be plated, forming a Sn-Ni alloy plated layer with the film thickness of 0.1-0.5 μm including 60-90 mass% of Sn, on one side of the base sheet, and then bright finish rolling the surface with the elongation rate of 0.2-1%. The base sheet is preferably strike plated with Ni beforehand.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for a battery can, a spring material for a contact, etc., and has a low contact resistance and a high glossiness.
The present invention relates to a method for producing an i-alloy-plated stainless steel sheet.

[0002]

2. Description of the Related Art A stainless steel sheet has a high contact resistance due to the formation of a passivation film on its surface and is not suitable as it is for applications such as battery cans and contact spring materials which require a low contact resistance. For this reason, stainless steel whose contact resistance has been reduced by applying Ni plating is used for applications such as battery cans and contact spring materials, and Ni plated materials having a glossy surface are preferred in order to improve appearance.

[0003] Shin Ni with a glossy surface on a stainless steel plate
As a method of forming a plating layer, a method of applying bright Ni plating after strike plating is generally used. For strike plating, for example, a wood bath having a pH of 1 or less made of nickel chloride and sulfuric acid is used. For bright Ni plating, for example, a plating bath in which an organic compound such as ketone, aldehyde, and sulfonate is added as a brightener to a Watt bath having a pH of 3.5 to 5.0 containing nickel sulfate, nickel chloride, boric acid, or the like. used. The bright Ni plating layer is formed with a thickness of, for example, 2 to 4 μm.

[0004] In addition to bright Ni plating, buffing or the like can also be used to impart gloss to the Ni plating layer. In this case, a matte Ni plating layer of, for example, 3 to 5 μm is formed by electroplating using a Watt bath or a total chloride bath to which no brightener is added, and then the matte Ni plating layer is buff-polished. In Japanese Patent Application Laid-Open No. 63-145793, a thickness of 0.01 to 0.5 μm is applied to the surface of a stainless steel plate having a surface gloss.
It is introduced that a stainless steel Ni-plated material having excellent workability and surface gloss and maintaining low contact resistance for a long period of time can be manufactured by forming a thin matte Ni plating layer with a thin film.

[0005]

In bright Ni plating using a plating bath to which a brightener is added, it is generally necessary to make the Ni plating layer thick. Also, since brightener components in the plating bath are quickly consumed by the electrolytic reaction, when bright Ni plating is applied to continuous plating on an industrial scale with a wide coil, the brightener is continuously replenished in the plating bath. It is necessary to secure a certain amount of brightener. However, it is very difficult to control the concentration of the brightener in the plating bath, and the quality of the Ni plating layer becomes unstable because the gloss of the Ni plating layer easily changes in accordance with the concentration change of the brightener. In addition, since an expensive brightener is consumed and a thick Ni plating layer is required, the manufacturing cost tends to be high.

When buffing the matte Ni plating layer to impart gloss, the buffing removes the Ni plating layer, so that it is necessary to form the matte Ni plating layer with an excessive thickness. Moreover, a buffed linear pattern is formed on the surface of the buffed Ni plating layer, so that it is difficult to obtain a beautiful surface.

[0007] In the method of ensuring glossiness with a thin matte Ni plating layer, when a stainless steel plating material is formed into a shape such as a battery can, the matte Ni plating layer contacts the mold at the processing portion where the matte portion contacts the mold. The surface of the matte Ni plating layer becomes a high gloss surface due to friction. As a result, the matte Ni
Although the appearance of the plating layer is exhibited, the appearance becomes high gloss on the side wall portion of the battery can, the difference in gloss between the battery can head and the side wall portion of the battery can becomes remarkably large, and the appearance of the product deteriorates. Moreover, the stainless steel sheet on which the soft matte Ni plating layer is formed as compared to the bright Ni plating layer is liable to generate an infinite number of scratches in the punching, pressing, assembling steps, etc. in the battery can manufacturing process. It tends to be a battery can with a defective appearance with many scratches.

In applications such as battery cans and contact spring materials, in addition to high gloss, the contact resistance of the plating layer is an important factor in determining performance. The bright Ni plating layer obtained from the brightener-added plating bath has excellent surface gloss, but when exposed to a high-temperature and high-humidity atmosphere for a long time, the brightener (organic substance) contained in the plating layer is decomposed to produce Ni plating. Oxidation of the layer surface is accelerated. In this regard, the bright Ni plating layer has a very high contact resistance due to surface oxidation (specifically, 1
000 mΩ or more), which is not suitable for applications such as battery cans and contact spring materials. On the other hand, a matte Ni plating layer obtained from a plating bath without a brightener increases the contact resistance to about 70 mΩ when exposed to a high-temperature and high-humidity atmosphere for a long time, and is required as a lithium button battery incorporated in a watch or the like. It greatly exceeds the value of 20 mΩ or less. In addition, in the plating layer provided with gloss by buff polishing, a film of Ni oxide or the like is easily formed on the surface of the Ni plating layer by heating during the buff polishing, and the contact resistance is reduced when exposed to a high temperature and high humidity atmosphere for a long time. It increases to about 500 mΩ.

[0009]

DISCLOSURE OF THE INVENTION The present invention has been devised in order to solve such a problem. A stainless steel plate whose surface roughness has been adjusted is used as a plating base plate, on which a strike is performed under specific conditions. S obtained by plating and main plating
Bright temper rolling of an n-Ni alloy-plated stainless steel sheet eliminates the need for a brightener,
An object of the present invention is to produce a Sn—Ni-plated stainless steel sheet which is excellent in glossiness, has low contact resistance, and is suitable as a battery can, a contact spring agent and the like.

In order to achieve the object, the production method of the present invention uses a ferritic stainless steel plate or an austenitic stainless steel plate having a surface roughness of Ra 0.050 μm or less as a plating base plate, and Sn: 60 to 9 on one surface of the plating base plate.
A Sn—Ni alloy plating layer having a thickness of 0.1 to 0.5 μm containing 0% by mass is formed, and then subjected to bright temper rolling at an elongation of 0.2 to 1%. It is preferable that the stainless steel plate to be subjected to the Sn-Ni alloy plating is subjected to Ni strike plating in advance.

[0011]

The present inventors have replaced the Ni-plated stainless steel sheet used for applications such as battery cans and contact spring materials with S
The use of an n-Ni alloy plated stainless steel sheet was studied.
The Sn-Ni alloy plating layer has very little formation of oxide films and corrosion products on the plating layer surface even in a high-temperature and high-humidity environment, and has excellent corrosion resistance. Keep low over time. In addition, by using a stainless steel plate having a very small surface roughness as a plating base plate, a surface state suitable for forming fine electrodeposits is utilized, and a plated surface exhibiting good gloss can be obtained.

For a Sn—Ni alloy-plated stainless steel sheet, a material that affects low contact resistance and gloss required for a battery can, a contact spring material, etc., and a Sn—Ni alloy plating layer of Sn
The effects of content, bright temper rolling, etc. were investigated. As a result, the contact resistance value and the glossiness of the Sn—Ni alloy plating layer were determined based on the surface roughness of the stainless steel sheet used as the plating base sheet, the Sn content of the Sn—Ni alloy plating layer, and the elongation during bright pass rolling. It was found that the press formability and scratch resistance changed. When the surface roughness, Sn content and elongation are maintained within the ranges specified in the present invention, Sn—Ni alloy plated stainless steel that satisfies all of contact resistance, gloss, press formability and scratch resistance. It has been found that a steel sheet can be obtained.

[Surface Roughness of Original Plate for Plating] If the surface roughness of the stainless steel sheet used as the original plate for Sn—Ni alloy plating is large, even if Ni strike plating is applied, the surface is not sufficiently smoothed and the Ni strike plating layer The deposited particles of the Sn—Ni alloy plating layer formed thereon become large. Bright passivation with high elongation is required to impart gloss to the Sn-Ni alloy plating layer composed of large electrodeposits, and as a result, press formability is significantly deteriorated. The smoothing action by Ni strike plating becomes remarkable when the surface roughness of both the ferrite and austenite is set to Ra: 0.05 μm or less. The surface roughness is Ra: 0.
If the thickness exceeds 05 μm, thick Ni strike plating and Sn—Ni alloy plating are required to impart gloss to the plating layer surface by bright pass rolling.

[Sn-Ni alloy plating] When the surface roughness of the plating base plate is very small, the Sn-Ni alloy plating layer can be formed directly on the surface of the plating base plate. However, the plating base plate is usually formed by Ni strike plating. After smoothing the surface, a Sn—Ni alloy plating layer is formed. Sn
A plating bath made of tin chloride, nickel chloride, potassium pyrophosphate, glycine, or the like is used for the Ni alloy plating.

The Sn—Ni alloy plating layer contains 60% by mass or more of Sn in order to ensure good press formability. If the Sn content is less than 60% by mass, the plating layer becomes hard, and a marked crack occurs in the plating layer in a processed portion during press working or the like, and the appearance and corrosion resistance of the product are reduced. Conversely, a Sn—Ni alloy plating layer having a Sn content of more than 90% by mass maintains low contact resistance even when exposed to a high-temperature and high-humidity atmosphere for a long time, but is very soft and is punched in a battery manufacturing process. The surface of the plating layer is apt to be scratched in the press working, assembling process, etc., resulting in a product having poor appearance and lowering the product yield.

The Sn—Ni alloy plating layer is formed with a thickness of 0.1 μm or more in order to maintain a low contact resistance. 0.1
If the film thickness does not reach μm, the surface of the Ni strike plating will be exposed, and if used for a long time in an atmosphere exposed to a severe environment, the exposed portion of the Ni strike plating will be oxidized,
The contact resistance increases. However, thick plating exceeding 0.5 μm consumes a large amount of expensive Sn or Ni and is not economical.

[Bright temper rolling] Bright temper rolling of a stainless steel sheet on which an Sn-Ni alloy plating layer is formed at an elongation of 0.2 to 1% gives a bright Ni plating obtained in a plating bath containing an organic brightener. Sn-N with excellent glossiness of 1000 or more comparable to the surface glossiness of stainless steel sheet
An i-alloy plated stainless steel sheet is manufactured. If the elongation percentage of the bright skin pass rolling is less than 0.2%, the smoothening action by the bright skin pass rolling is insufficient and sufficient gloss cannot be obtained. Conversely, if the elongation exceeds 1%, glossiness higher than that of bright Ni plating can be obtained, but mechanical properties such as 0.2% proof stress and elongation are adversely affected, and the press formability of the Sn—Ni alloy-plated stainless steel sheet is increased. Decrease. In bright temper rolling,
It is preferable to use a surface finishing roll of 320 or more.

[0018]

Example 1 As a plating base plate, surface roughness Ra: 0.0
SUS43 with a thickness of 34 to 0.072 μm and a thickness of 0.20 mm
0 stainless steel plate was used. Sodium orthosilicate 50
The plating base plate was immersed in an alkaline electrolytic bath having a liquid temperature of 55 ° C. and a g / l solution, and subjected to cathodic electrolysis at a current density of 5 A / dm ² for 10 seconds to perform electrolytic degreasing. After the electrolytically degreased plating base plate is washed with water, 10 g / l of sulfuric acid is added to a sulfuric acid bath at a bath temperature of 25 ° C.
The plating plate was pickled by immersion for 2 seconds. The pickled plating base plate is immersed in a Ni strike plating bath,
A 0.25 μm-thick Ni strike plating layer was formed under the following conditions.

After the Ni strike-plated stainless steel plate was washed with water, a Sn—Ni alloy plating layer was formed under the following conditions. The thickness of the Sn—Ni alloy plating layer is in the range of 0.05 to 0.50 μm by changing the energization time.
The n content can be varied from 42 to 96 by changing the plating bath composition.
It was adjusted in the range of mass%.

The obtained Sn—Ni alloy plated stainless steel plate was subjected to bright temper rolling at various elongations using a 320th surface finishing roll. A test piece was cut out from a bright temper-rolled Sn—Ni alloy-plated stainless steel sheet, and the gloss was measured, and the test piece was subjected to a press forming test and an accelerated deterioration test. The gloss was measured using a portable surface gloss meter (Murakami Color Research Laboratory Co., Ltd.) at a measurement angle of 2
It was measured at 0 degrees and indicated by the numerical value.

In the press forming test, 100 test pieces were cup-drawn into a shape having an outer diameter of 40 mm and a forming height of 30 mm.
The surface shape of the molded product head was observed, and the presence or absence of defects was measured with a non-contact height meter. From the measurement results, out of 100 molded products, the press formability was evaluated as 形状 when the occurrence rate of shape defects was 0%, Δ when 1 to 10%, and X when more than 10%. Further, the side walls rubbed by the mold during press molding were observed to check for flaws. According to the survey results, the molded article 100
Of the pieces, those having a flaw occurrence rate of 0% were evaluated as ○, 1 to 10% as Δ, 1
Those exceeding 0% were evaluated as x, and the scratch resistance was evaluated. In the accelerated aging test, the test piece was left in a high-temperature and high-humidity chamber at a temperature of 60 ° C. and a relative humidity of 90% for 80 days, and then an applied current of 1 was measured using a contact resistance distribution measuring device (manufactured by Yamazaki Seiki Laboratory Co., Ltd.).
The contact resistance was measured under the conditions of 0 mA and a contact load of 100 gf.

As can be seen from the survey results in Table 1, in Test Nos. 1 to 10 (Examples of the present invention), the gloss was 1000 in all cases.
As described above, the press formability and the scratch resistance were good, and the contact resistance value after the accelerated deterioration test was as low as 20 mΩ or less. On the other hand, in Test Nos. 11 and 12 in which the surface roughness of the original plating plate was large and in Test No. 13 in which a thin Sn—Ni alloy plating layer was formed, the gloss of the plated surface was 100%.
In Test No. 13, the contact resistance after the accelerated deterioration test was increased to 20 mΩ or more. In test No. 14 in which the elongation percentage was higher than 1% by bright pass rolling, the press formability was inferior. In Test No. 15, in which the Sn—Ni alloy plating layer in which the Sn content did not reach 60% by mass was formed, the glossiness was less than 1000, and the contact resistance after the accelerated deterioration test exceeded 20 mΩ. Test No. 16 in which a Sn—Ni alloy plating layer containing Sn exceeding 90% by mass was formed.
Was markedly inferior in scratch resistance. Furthermore, matte N
In Test No. 17 in which the i-plated layer was formed, the glossiness of the surface of the plated layer was low, and the scratch resistance was poor. In Test No. 18 in which a bright Ni plating layer was formed, the press formability was poor, and a very high contact resistance of 1700 mΩ was shown after the accelerated deterioration test.

[0023]

[0024]

Embodiment 2 As a plating base plate, the surface roughness was Ra: 0.
Plate thickness 0.20mm adjusted to 037-0.069μm
SUS304 stainless steel plate was used. Pretreatment, Ni strike plating (film thickness 0.15 μm) as in Example 1.
m) and Sn-Ni alloy plating. For each of the obtained plated materials, the glossiness, press formability, scratch resistance, and contact resistance after the accelerated deterioration test were examined in the same manner as in Example 1. As can be seen from the survey results in Table 2, test numbers 19 to
No. 28 (Example of the present invention) showed good results in all the tests.

On the other hand, in Test Nos. 29 and 30 using a plating base plate having a large surface roughness and Test No. 31 in which a thin Sn—Ni alloy plating layer was formed, the contact resistance after the accelerated deterioration test was high. Indicated. Further, in Test No. 32 in which the bright skin pass rolling with an elongation of more than 1% was performed, press formability was inferior. Sn: less than 60% by mass of Sn-N
In Test No. 33 in which the i-alloy plating layer was formed, the glossiness and the contact resistance were inferior. Conversely, Sn exceeding 90% by mass
No. 34 in which a Sn—Ni alloy plating layer containing
Was inferior in scratch resistance. Further, in Test No. 35 in which a matte Ni plating layer was formed, the glossiness and scratch resistance were poor, and in Test No. 36 in which a bright Ni plating layer was formed, the press formability was poor and the contact resistance after the accelerated deterioration test was high. showed that.

[0026]

[0027]

As described above, the Sn—Ni alloy-plated stainless steel sheet manufactured according to the present invention exhibits low contact resistance even after prolonged exposure to a high-temperature and high-humidity atmosphere, and has a glossy plated surface. Is also excellent. Therefore, it is used in various fields such as battery can materials and contact spring materials which require high gloss and low contact resistance.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Eiji Watanabe, Inventor 5: Ishizu Nishimachi, Sakai City, Osaka Prefecture Nisshin Steel Co., Ltd. (72) Inventor Masaru Sato 5: Ishizu Nishimachi, Sakai City, Osaka Nissin Steel Co., Ltd. F-term in Technical Research Institute (reference) 4E002 AD06 BC05 CB03 4K024 AA03 AA23 AB01 BA04 BB09 BB10 BC01 CA02 CA03 CA04 CA06 DA02 DA03 DA04 DA09 GA02 GA07

Claims (2)

[Claims] 1. A ferrite stainless steel plate or an austenitic stainless steel plate having a surface roughness Ra of 0.050 μm or less is used as a plating base plate, and Sn:
0.1-0.5 μm thick Sn containing 60-90% by mass
-Forming a Ni alloy plating layer, and then elongating 0.2 to 1
%, Characterized in that it is subjected to bright temper rolling at a rate of 0.1%, and has a low contact resistance and is excellent in glossiness. 2. The manufacturing method according to claim 1, wherein the plating base plate is subjected to Ni strike plating before forming the Sn—Ni alloy plating layer.