KR20140053138A - Surface-treated steel plate, fuel pipe, cell can - Google Patents

Abstract

A surface-treated steel sheet having an iron-nickel alloy layer formed on an outermost surface thereof, characterized in that an Fe / Ni value by Auger electron spectroscopy on the surface of the iron-nickel alloy layer is in the range of 0.3 to 2.0 Treated steel sheet. According to the present invention, it is possible to provide a surface-treated steel sheet in which the occurrence of pitting corrosion is effectively suppressed when exposed to various fuels such as automotive fuel oil, and also has excellent corrosion resistance.

Description

[0001] SURFACE-TREATED STEEL PLATE, FUEL PIPE, CELL CAN [0002]

The present invention relates to a surface treated steel sheet, a fuel pipe obtained by using the surface treated steel sheet, and a battery can.

Background Art [0002] Conventionally, as a fuel pipe material for automobiles and the like, a steel sheet plated with Sn-Pb alloy or a multilayer plated steel sheet plated with nickel plating and Sn-Pb alloy is mainly used.

However, since the Sn-Pb alloy does not have corrosion resistance to water and is also potentially higher than Fe, pinholes are generated in the case of performing the hot-dip coating, and the moisture which is inevitably contained in the gasoline fuel There is a problem that pitting corrosion occurs due to a corrosive substance such as copper or the like.

On the other hand, for example, Patent Document 1 discloses a plated steel sheet obtained by forming a composite plating layer in which fluorine compound particles are dispersed in a nickel plating layer by electroplating on the surface of a steel sheet, and then heat- .

Patent Document 1: JP-A-8-232092

However, as a result of the inventors' study, it has been recognized that the coated steel sheet disclosed in Patent Document 1 does not necessarily have an effect of inhibiting the formation of formaldehyde. In addition, since the fluorine compound particles are used in the Patent Document 1, it is not preferable from the viewpoint of environmental safety.

An object of the present invention is to provide a surface-treated steel sheet in which the occurrence of formulas is effectively inhibited and also has excellent corrosion resistance. It is also an object of the present invention to provide a fuel pipe obtained by using such a surface-treated steel sheet.

The inventors of the present invention have conducted intensive studies in order to achieve the above object and as a result have found that an iron-nickel alloy layer having an Fe / Ni value of 0.3 to 2.0 by Auger electron spectroscopy on its surface, The present invention has been accomplished on the basis of this finding.

That is, according to the present invention, there is provided a surface-treated steel sheet in which an iron-nickel alloy layer is formed on the outermost surface, wherein Fe / Ni value in the surface of the iron- Wherein the surface treated steel sheet is characterized in that

In the surface-treated steel sheet of the present invention, preferably, the immersion potential of the iron-nickel alloy layer in an aqueous solution of sodium chloride is in the range of +0.05 to +0.25 V relative to the immersion potential in an aqueous solution of sodium chloride alone. That is, the 'immersion potential of the iron-nickel alloy layer' - 'immersion potential of the iron core' = +0.05 to +0.25 V.

Further, according to the present invention, there is provided a fuel pipe formed by molding any one of the above-mentioned surface-treated steel sheets.

Further, according to the present invention, there is provided a battery can made by molding any one of the above-mentioned surface-treated steel sheets.

According to the present invention, by forming an iron-nickel alloy layer having an Fe / Ni value in the range of 0.3 to 2.0 on the outermost surface by the Au-e electron spectroscopy analysis on the surface thereof, the formation of the formula is effectively inhibited, This excellent surface-treated steel sheet and the fuel pipe and the battery can obtained using such a surface-treated steel sheet can be provided.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a view for explaining a corrosion mode of a metal plate. FIG.

Hereinafter, the surface treated steel sheet of the present invention will be described.

The surface-treated steel sheet of the present invention is a surface-treated steel sheet having an iron-nickel alloy layer formed on the outermost surface thereof. The surface-treated steel sheet has an Fe / Ni value of 0.3 to 2.0 .

<Steel plate>

The steel sheet to be the substrate of the surface-treated steel sheet of the present invention is not particularly limited as long as the steel sheet is excellent in workability. For example, aluminum-killed steel (carbon content: 0.01 to 0.15 wt%), An extremely low carbon steel of 0.003 wt% or less, or a non-crucible extremely low carbon steel to which Ti or Nb is further added to an extremely low carbon steel.

In the present invention, hot rolled plates of these steels are pickled to remove scale (oxide film) on the surface, cold rolled, then electrolytically washed with rolling oil, and then subjected to annealing, skin pass rolling ) Is used as a substrate. In this case, the annealing may be either continuous annealing or box annealing, and is not particularly limited.

<Iron-Nickel Alloy Layer>

In the surface-treated steel sheet of the present invention, an iron-nickel alloy layer is formed on the outermost surface. The Fe / Ni value (molar ratio of Fe / Ni) by the Auger electron spectroscopy analysis on the surface of the iron-nickel alloy layer is in the range of 0.3 to 2.0, preferably 0.3 to 1.5.

In the present invention, by controlling the Fe / Ni value of the surface of the iron-nickel alloy layer by the Auger electron spectroscopic analysis within the above range, the generation of the formula can be effectively suppressed when exposed to various fuels such as automotive fuel oil, As a result, it is possible to obtain excellent corrosion resistance.

Here, conventionally, nickel-plated steel sheets have been used in fields where corrosion resistance is required, such as pipes for various fuel such as fuel oil for automobile and battery cans because of high corrosion resistance, but on the other hand, nickel plating layers are formed by electroplating , Pinholes are generated. In the case of the nickel-plated steel sheet, there is a problem that a formula due to such pinholes or defects occurs, and leakage of contents such as fuel is caused by the formula.

On the other hand, the inventors of the present invention have found that by forming an iron-nickel alloy layer whose Fe / Ni value is controlled in the above range by Ouzer electron spectroscopy on the surface of a steel sheet, the generation of the formula is effectively ensured while securing excellent corrosion resistance of the nickel plating layer The present invention has been completed. Particularly, the inventors of the present invention have found that, by dispersing iron in a nickel layer having a high corrosion resistance, the occurrence of a formula can be effectively suppressed while ensuring excellent corrosion resistance of the nickel plating layer.

On the other hand, if the Fe / Ni value is too high, the corrosion resistance of the iron-nickel alloy layer is deteriorated and the corrosion on the entire surface of the alloy layer It speeds up. Here, with reference to Fig. 1, the corrosion mode of a metal plate such as a steel plate will be described. Fig. 1 (A) is a view showing a metal plate before corrosion occurs, Fig. 1 (B) is a view showing a metal plate on which a formula is formed, and Fig. 1 (A) to 1 (C), it is assumed that the metal plate is in contact with the corrosive liquid on the upper side of the drawing. In this case, in addition to the case where the corrosive liquid directly contacts the metal plate in a liquid state, in addition to the case where the corrosive liquid vaporizes and comes into contact with the metal plate in a gaseous state, and the gas vaporized by the corrosive liquid precipitates as a droplet on the metal plate surface . As shown in FIG. 1 (B), the formula is generated locally in the thickness direction of the metal plate. However, as shown in FIG. 1 (C), the front corrosion occurs at the front surface of the metal plate, The thickness of the metal plate is reduced. That is, FIG. 1C shows an example in which the thickness of the metal plate is decreased from t ₀ to t ₁ . In the present invention, when the Fe / Ni value is too low, a formula is generated as shown in FIG. 1 (B). On the other hand, if the Fe / Ni value is too high, The speed of progress is accelerated, and as a result, there arises a problem that the entire thickness is thinned.

On the other hand, in the present invention, the Fe / Ni value by Auger electron spectroscopy can be measured by, for example, the following method. That is, first, the surface of the iron-nickel alloy layer is measured using a scanning electrometric spectroscopic analyzer (AES) to calculate atomic% of Ni and Fe on the surface of the iron-nickel alloy layer. The Fe / Ni value (atomic% of Fe / atomic% of Ni) is calculated by measuring the results of the measurement with a scanning electron-ophthalmograph spectrometer on five of the surfaces of the iron-nickel alloy layer and averaging the obtained results . On the other hand, in the present invention, a peak of 820 to 850 eV is taken as a peak of Ni and a peak of 570 to 600 eV is taken as a peak of Fe among the peaks obtained by measurement using a scanning electron microscope, The total amount of Fe is set to 100 atomic%, and atomic% of Ni and Fe is measured.

The Fe-Ni alloy layer of the surface-treated steel sheet of the present invention has an Fe / Ni value in the above range, and the immersion potential in an aqueous solution of sodium chloride is not higher than the Fe / It is preferably in the range of +0.05 to +0.25 V, more preferably +0.07 to +0.22 V, relative to the immersion potential. That is, it is preferable that the difference from the immersion potential of the iron group in the aqueous solution of sodium chloride is within the above range.

In the present invention, besides the Fe / Ni value obtained by the Auger electron spectroscopic analysis, the effect of inhibiting the formation of the formulas can be further improved by setting the immersion potential in the sodium chloride aqueous solution to the above range. When the immersion potential of the iron-nickel alloy layer is too low (the difference from the immersion potential of the iron itself is too small), the corrosion resistance of the iron-nickel alloy layer is lowered and the corrosion rate at the entire surface of the alloy layer is accelerated. On the other hand, if the immersion potential is too high (the difference from the immersion potential of the iron group is too large), the effect of inhibiting the formation of formaldehyde is lowered.

In the present invention, the immersion potential of the iron-nickel alloy layer in the sodium chloride aqueous solution can be measured by, for example, immersing the iron-nickel alloy layer in an aqueous solution of 5% by weight sodium chloride and measuring the natural potential after 15 minutes, This can be used as an immersion potential. Here, the time for immersing the iron-nickel alloy layer in the sodium chloride aqueous solution can be set based on the time required until the value of the natural potential after stabilization is stabilized. For example, as described above, . As a specific measurement method of the immersion potential, measurement was carried out under the conditions of a reference electrode: Ag / AgCl, a counter electrode: Pt, and a measurement temperature of 35 ° C with an electrolytic solution containing 5% by weight of sodium chloride aqueous solution. It can be measured by measuring the natural potential and determining the difference between the obtained natural potential and the spontaneous potential for Ag / AgCl in Fe.

On the other hand, in the iron-nickel alloy layer of the present invention, the potential difference of the immersion potential of the iron-nickel alloy layer in an aqueous solution of sodium chloride with respect to the immersion potential of the iron itself is the difference between the immersion potential of the iron- Quot; immersion potential &quot;

The method for forming the iron-nickel alloy layer in the present invention is not particularly limited, and for example, the following method can be used. That is, a method of forming a nickel plating layer on the surface of a steel sheet by using a nickel plating bath, and subsequently subjecting the surface to heat treatment, and the like. However, the method of forming the iron-nickel alloy layer in the present invention is not particularly limited by such a method.

Specifically, first, as a nickel plating bath, a plating bath commonly used in nickel plating, that is, a plating bath using a watt bath, a sulfamate bath, a citric acid bath, a fluorinated water bath, a chloride bath, A nickel plating layer of 0.3 to 2 탆 is formed. For example, the nickel plating layer may be formed to have a pH of 3 to 4.8, a bath temperature of 40 to 70 占 퐉, a bath temperature of 200 to 350 g / L, a nickel chloride of 20 to 50 g / Lt; 0 &gt; C and a current density of 5 to 30 A / dm &lt; 2 &gt;. If the thickness of the nickel plating layer is too thin, the alloy layer formed in the subsequent step becomes thinner, so that corrosion resistance on the entire alloy layer may be deteriorated. On the other hand, if it is too thick, iron is not sufficiently diffused in the subsequent heat treatment, There is a fear that it becomes impossible to form the magnetic recording medium, resulting in an increase in cost.

Subsequently, the steel sheet on which the nickel plating layer is formed is heat-treated by thermal diffusion to form an iron-nickel alloy layer (iron-nickel diffusion layer). In this case, the heat treatment may be performed by any of continuous annealing and box annealing, and the heat treatment conditions may be suitably selected according to the thickness of the nickel plating layer. For example, when heat treatment is performed by box annealing The following conditions are preferably satisfied.

Heat treatment temperature: 400 to 800 DEG C

Heat treatment time: 30 minutes to 16 hours

Heat treatment atmosphere: Non-oxidizing atmosphere or reducing protective gas atmosphere

In the case of continuous annealing, the following conditions are preferable.

Heat treatment temperature: 600 to 900 占 폚

Heat treatment time: 3 seconds to 120 seconds

Heat treatment atmosphere: Non-oxidizing atmosphere or reducing protective gas atmosphere

On the other hand, in both of the box-type annealing and the continuous annealing, when the thickness of the nickel plating layer is relatively thin under the above-described conditions, it is preferable to relatively lower the heat treatment temperature and relatively shorten the heat treatment time. Further, under the above conditions, when the thickness of the nickel plated layer is relatively large, it is preferable that the heat treatment temperature is relatively high and the heat treatment time is relatively long. When the heat treatment atmosphere is a reducing protective gas atmosphere, a protective gas composed of 75% hydrogen-25% nitrogen produced by the ammonia cracking method called hydrogen enrichment annealing with good heat transfer is used as the protective gas .

If the heat treatment temperature is too low or the heat treatment time is too short, the thermal diffusion in the iron-nickel alloy layer becomes insufficient, and the Fe / Ni value on the surface of the iron-nickel alloy layer is lowered by Auger electron spectroscopy, The suppression effect of the present invention can not be obtained. On the other hand, if the heat treatment temperature is too high or the heat treatment time is too long, the Fe / Ni value on the surface of the iron-nickel alloy layer due to the Auelectron spectroscopic analysis becomes too high and the corrosion resistance of the iron- Corrosion rate is accelerated.

As described above, the surface-treated steel sheet of the present invention can be obtained by forming the predetermined iron-nickel alloy layer on the steel sheet. The surface-treated steel sheet of the present invention effectively inhibits the generation of a formula when exposed to corrosive liquid contents or vapor, when exposed to various fuels such as automobile fuel oil, or when exposed to an electrolyte of a battery And is also excellent in corrosion resistance. Therefore, the surface-treated steel sheet of the present invention can be suitably used for use in a state exposed to liquid contents such as various fuels. Specifically, it can be suitably used for various purposes such as a fuel pipe, a fuel tank, and a battery can. Alternatively, the surface-treated steel sheet of the present invention can exhibit excellent corrosion resistance compared with materials conventionally used for beverage cans and food cans, even when used for beverage cans and food cans, Can be used to make. Particularly, since the iron-nickel alloy layer constituting the surface-treated steel sheet of the present invention is sufficiently alloyed with iron and nickel, the elution of iron or nickel can be suitably suppressed even when it is used for beverage cans and food cans.

<Fuel pipe>

The fuel pipe of the present invention can be obtained by molding the above-mentioned surface-treated steel sheet of the present invention. Specifically, in the fuel pipe of the present invention, the above-described surface-treated steel sheet of the present invention is modified in shape by a leveler, cut with a slitter to a predetermined outer diameter, and then the iron- And the end faces in the longitudinal direction are seam-welded by high frequency induction welding. Since the fuel pipe of the present invention thus obtained is made of the above-mentioned surface-treated steel sheet of the present invention, the occurrence of the formulas is effectively suppressed when exposed to various fuels such as automotive fuel oil, . Therefore, the fuel pipe of the present invention can be suitably used for various purposes such as, for example, an oil supply pipe for introducing fuel into a tank, a pipe for introducing fuel from a tank to an engine, and a pipe for ventilation. Examples of the fuel in this case include various fuels for automobiles such as gasoline, light oil, bioethanol, and biodiesel fuel.

<Battery can>

The battery can of the present invention is obtained by using the above-mentioned surface-treated steel sheet of the present invention. Specifically, the battery can of the present invention can be manufactured by forming the surface-treated steel sheet of the present invention by iron-nickel alloy layer by drawing, ironing, DI (drawing-ironing) or DTR (Draw Thin Redraw) And then molding it so as to be on the inner surface side of the battery can. Since the battery can of the present invention thus obtained uses the above-described surface-treated steel sheet of the present invention, the occurrence of the formula is effectively suppressed and the corrosion resistance is excellent. Particularly, the above-mentioned surface-treated steel sheet of the present invention can effectively inhibit the occurrence of formulations not only when exposed to various fuels such as automobile fuel oil but also when used in contact with a strongly alkaline electrolytic solution, Corrosion resistance can be realized. Therefore, the battery can of the present invention can be suitably used as a battery container of a battery using a strong alkaline electrolyte such as an alkaline battery or a nickel-metal hydride battery.

Example

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

The definition and evaluation method of each characteristic are as follows.

<Fe / Ni value>

The outermost layer of the iron-nickel alloy layer of the surface-treated steel sheet was etched to about 10 nm, and the surface-treated steel sheet after etching was measured for atomic% of Ni and Fe at five locations using a scanning electron microscope (AES) , And the Fe / Ni value was determined by the Auger electron spectroscopic analysis.

<Immersion potential>

The surface-treated steel sheet masked with an area of? 5 mm was immersed in a 5 wt% aqueous solution of sodium chloride to prepare an Ag / AgCl alloy layer of the iron-nickel alloy layer under the conditions of reference electrode: Ag / AgCl, counter electrode: Pt, The spontaneous potential against AgCl was measured and the immersion potential in the aqueous sodium chloride solution of the iron-nickel alloy layer was measured by determining the difference between the obtained spontaneous potential and the spontaneous potential for Ag / AgCl in Fe.

<Formal>

The surface-treated steel sheet masked with the area of 20 x 20 mm was immersed in a 5 wt% aqueous solution of sodium chloride, and the potential was forcefully and slowly applied at a reference electrode: Ag / AgCl, counter electrode: Pt, , And the corrosion was promoted by keeping the surface-treated steel sheet at a potential at the time when corrosion of the surface-treated steel sheet was started for 30 minutes. As a result of accelerating the corrosion, it was visually observed whether or not the formula occurred in the surface-treated steel sheet in the area of 20 × 20 mm.

&Quot; Example 1 &

A steel sheet obtained by annealing a cold rolled plate (thickness 0.25 mm) of a low-carbon aluminum-killed steel having the following chemical composition as a disk was prepared.

C: 0.045% by weight, Mn: 0.23% by weight, Si: 0.02% by weight, P: 0.012% by weight, S: 0.009% by weight, Al: 0.063% by weight, N: 0.0036% by weight, balance: Fe and unavoidable impurities

Then, the prepared steel sheet was subjected to alkali electrolytic degreasing and sulfuric acid soaking, and then nickel plating was performed under the following conditions to form a nickel plating layer having a thickness of 0.5 탆.

Bath composition: 250 g / L of nickel sulfate, 45 g / L of nickel chloride, 30 g / L of boric acid

pH: 3 to 4.8

Bath temperature: 60 ℃

Current density: 10 A / dm 2

Subsequently, the steel sheet on which the nickel plating layer was formed was subjected to heat treatment under the conditions of a non-oxidizing atmosphere (vacuum annealing) at a temperature of 650 DEG C for 2 hours by box annealing, and the nickel plating layer was subjected to thermal diffusion treatment to obtain iron- Alloy layer was formed to obtain a surface-treated steel sheet. Each of the thus-obtained surface-treated steel sheets was evaluated for Fe / Ni value, immersion potential in an aqueous solution of sodium chloride, and occurrence of formulations by the above-mentioned method according to the above-mentioned Auelectronics Spectroscopy. The results are shown in Table 1.

&Quot; Example 2 &quot;

A surface treated steel sheet was obtained in the same manner as in Example 1 except that the heat treatment time was changed to 4 hours, and the same evaluation was made. The results are shown in Table 1.

&Quot; Example 3 &quot;

A surface-treated steel sheet was obtained in the same manner as in Example 2 except that the thickness of the nickel plating layer was 1 mu m, and the same evaluation was made. The results are shown in Table 1.

&Quot; Example 4 &quot;

A surface treated steel sheet was obtained in the same manner as in Example 1 except that the heat treatment time was changed to 8 hours, and the same evaluation was made. The results are shown in Table 1.

&Quot; Example 5 &quot;

A surface treated steel sheet was obtained in the same manner as in Example 3 except that the heat treatment time was changed to 8 hours, and the same evaluation was made. The results are shown in Table 1.

&Quot; Example 6 &quot;

A surface treated steel sheet was obtained in the same manner as in Example 1 except that the thickness of the nickel plating layer was changed to 2 탆 and the heat treatment time was changed to 12 hours. The results are shown in Table 1.

&Quot; Example 7 &quot;

A surface-treated steel sheet was obtained in the same manner as in Example 1 except that the heat treatment was changed to continuous annealing at a temperature of 800 占 폚 for one minute in a non-oxidizing atmosphere (vacuum annealing). The results are shown in Table 1.

&Quot; Example 8 &quot;

A surface treated steel sheet was obtained in the same manner as in Example 7 except that the heat treatment temperature was changed to 900 캜, and the same evaluation was made. The results are shown in Table 1.

&Quot; Comparative Example 1 &

A surface treated steel sheet was obtained in the same manner as in Example 1 except that the heat treatment was not performed, and the same evaluation was made. The results are shown in Table 1.

&Quot; Comparative Examples 2 to 4 &quot;

A surface-treated steel sheet was obtained in the same manner as in Comparative Example 1 except that the thickness of the nickel plating layer was 1 占 퐉 (Comparative Example 2), 2 占 퐉 (Comparative Example 3), and 3 占 퐉 (Comparative Example 4). The results are shown in Table 1.

&Quot; Comparative Example 5 &

A surface-treated steel sheet was obtained in the same manner as in Example 1, except that the thickness of the nickel plating layer was 1 占 퐉. The results are shown in Table 1.

&Quot; Comparative Example 6 &

A surface-treated steel sheet was obtained in the same manner as in Example 1 except that the thickness of the nickel plating layer was 3 m, and the same evaluation was made. The results are shown in Table 1.

&Quot; Comparative Examples 7 and 8 &quot;

A surface treated steel sheet was obtained in the same manner as in Comparative Example 6 except that the heat treatment time was 4 hours (Comparative Example 7) and 8 hours (Comparative Example 8). The results are shown in Table 1.

&Quot; Comparative Example 9 &

A surface-treated steel sheet was obtained in the same manner as in Example 7 except that the heat treatment temperature was changed to 720 占 폚. The results are shown in Table 1.

&Quot; Comparative Example 10 &

A surface treated steel sheet was obtained in the same manner as in Example 3 except that the heat treatment was changed to continuous annealing at 720 占 폚 for 1 minute in a non-oxidizing atmosphere (vacuum annealing). The results are shown in Table 1.

&Quot; Comparative Example 11 &

A surface treated steel sheet was obtained in the same manner as in Comparative Example 10 except that the heat treatment temperature was changed to 800 캜, and the same evaluation was made. The results are shown in Table 1.

&Quot; Comparative Example 12 &

A surface-treated steel sheet was obtained in the same manner as in Comparative Example 10, except that the heat treatment temperature was changed to 900 캜. The results are shown in Table 1.

As shown in Table 1, in Examples 1 to 8 in which the Fe / Ni value by the Auger electron spectroscopy analysis on the surface of the iron-nickel alloy layer was in the range of 0.3 to 2.0, the occurrence of the formula was suppressed, . Further, in Examples 1 to 8, the immersion potential for the iron group in the aqueous solution of sodium chloride was also in the range of +0.05 to +0.25 V.

On the other hand, in Comparative Examples 1 to 4 in which a nickel plating layer was formed on the outermost surface in place of the iron-nickel alloy layer, and in Comparative Examples 5 to 12 in which Fe / Ni value was less than 0.3 as determined by the Auger electron spectroscopic analysis on the surface of the iron- The formula occurred. Therefore, when the fuel cell is used in a state of being exposed to corrosive liquid contents such as a fuel pipe or a battery can, there is a fear that the contents leak out through the formula.

Claims (4)

A surface-treated steel sheet having an iron-nickel alloy layer formed on the outermost surface thereof, wherein the surface of the iron-nickel alloy layer has an Fe / Ni value of 0.3 to 2.0 as determined by Auger electron spectroscopy analysis. The method according to claim 1,
Characterized in that the immersion potential of the iron-nickel alloy layer in an aqueous solution of sodium chloride is in the range of +0.05 to +0.25 V with respect to the immersion potential in an aqueous solution of sodium chloride alone. A fuel pipe formed by molding the surface-treated steel sheet according to claim 1 or 2. A battery can made by molding the surface-treated steel sheet according to claim 1 or 2.

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