WO1998015673A1

WO1998015673A1 - Surface treated steel sheet and method of manufacturing the same

Info

Publication number: WO1998015673A1
Application number: PCT/JP1997/003652
Authority: WO
Inventors: Hitoshi Ohmura; Tatsuo Tomomori; Hideo Ohmura
Original assignee: Toyo Kohan Co. Ltd.
Priority date: 1996-10-09
Filing date: 1997-10-09
Publication date: 1998-04-16
Also published as: JP3492704B2; AU4571597A; TW448247B

Abstract

The adherence of nickel-plated steel sheets, which is liable to occur when the nickel-plated steel sheets are thermally treated in an annealing furnace so as to disperse the nickel into the steel sheets, is prevented. A surface treated steel sheet characterized in that the steel sheet is obtained by plating both surfaces of a cold rolled steel sheet with nickel, plating one surface only of this nickel plated steel sheet with tin, immersing the resultant steel sheet in a bath containing ortho-sodium silicate as a main component or electrolyzing the same steel sheet in the same bath, to deposit silicon hydrate on the surface of the steel sheet, and then thermally treating the resultant steel sheet so as to disperse the nickel and tin therein.

Description

Specification

Surface treated steel sheet and its manufacturing method

The present invention relates to a surface-treated steel sheet which prevents the adhesion between steel sheets, which is likely to occur when manufacturing a steel sheet which has been subjected to a heat treatment of a plated steel sheet in an annealing furnace to diffuse the plating into the steel sheet, and to manufacture the same. It is about the law. Background art

A steel sheet plated with nickel or the like is usually plated, then wound up in a tight coil form, and then subjected to a box-type annealing furnace in a box-type annealing furnace to provide processing characteristics. Heat treated at around ° C. However, during this heat treatment, the diffusion of Nigel on the surface of the steel sheet is promoted, so that there is a problem that the wound and overlapped steel sheets come into close contact with each other. For this reason, conventionally, a wire or the like is wound into a coil together with the steel sheet as a spacer, and a heat treatment is performed in a state where an open coil is provided with a gap between the wound steel sheets, or an oxide stable at high temperatures. A method has been adopted in which a release agent such as carbide, nitride or the like is applied to the surface of the steel sheet in advance, and heat treatment is performed in a state where direct contact between the steel sheets is prevented.

'' However, the method of superposing the wire on the steel sheet and winding and annealing requires that the surface of the steel sheet is easily scratched and that extra work is required to wrap and unwind the wire. Absent. Furthermore, the method of applying a release agent to the surface of the steel sheet and annealing it increases the cost due to the use of the release agent, makes it difficult to remove the release agent, and changes the appearance of the steel sheet surface However, these methods are not practically applicable industrially.

In addition, although it is not a nickel-plated steel sheet, in the process of preventing adhesion of a cold-rolled steel sheet, it is also possible to prevent adhesion during annealing by attaching a release agent to an oxidizing substance such as titanium or aluminum on the steel sheet surface. (Eg, Japanese Patent Laid-Open Publication No. 63-23535427).

However, these oxides remain on the steel sheet surface after annealing, and the color tone of the steel sheet surface changes. And had the disadvantage that the appearance was impaired. For these reasons, in the heat treatment of the nickel-plated steel sheet, the above-mentioned wire was used, and no oxidizing substance was used.

An object of the present invention is to provide a surface-treated steel sheet which has been subjected to an adhesion preventing treatment for suppressing the adhesion between plated steel sheets when heat-treating a steel sheet coated with nickel or the like. Disclosure of the invention

The surface-treated steel sheet according to claim 1 is obtained by applying nickel plating to both sides of a cold-rolled steel sheet, then applying tin plating to only one side, and then immersing in a bath containing sodium orthosilicate as a main component or sodium orthosilicate. A silicon hydrate is precipitated on the surface by electrolytic treatment in a bath containing as a main component, and then heat treatment is performed to diffuse the adhesion.

Further, the surface-treated steel sheet according to claim 2 is provided with a nickel plating of 0.5 to 10 m thickness on both sides of the cold-rolled steel sheet, and then a tin plating of 0.05 to 5 m thickness only on one side. And then immersed in a bath containing sodium orthosilicate as a main component, or electrolytically treated in a bath containing sodium orthosilicate as a main component, so that the surface has a silicon amount of 0.1 to 3%. mg Zm ² of silicon hydrate was precipitated, followed by heat treatment to diffuse the target.

The surface-treated steel sheet according to claim 3 is obtained by sequentially applying nickel plating and tin plating on both sides of a cold-rolled steel sheet, and further immersing in a bath containing sodium orthosilicate as a main component or mainly using sodium orthosilicate. It is characterized in that silicon hydrate is deposited on the surface by electrolytic treatment in a bath as a component, and then heat treatment is performed to diffuse the nickel plating and tin plating.

Further, in the surface-treated steel sheet of claim 4, the cold-rolled steel sheet is provided with nickel plating having a thickness of 0.5 to 10 m on both sides, and thereafter, tin plating having a thickness of 0.5 to 5 m is provided on both sides. And then immersed in a bath containing sodium orthosilicate as a main component, or electrolytically treated in a bath containing sodium orthosilicate as a main component, so that the surface has a silicon amount of 0.1 to 3 mg. A silicon hydrate of Zm ² is precipitated, and then heat treatment is performed. Gel plating and tin plating are diffused.

Further, in the production method of claim 5, the cold-rolled steel sheet is plated with nickel on both sides, then tin-plated on only one side, and further immersed in a bath mainly containing sodium orthosilicate. Electrolytic treatment in a bath containing soda orthosilicate as a main component to precipitate silicon hydrate on the surface, followed by heat treatment to diffuse the nickel plating into the cold-rolled steel sheet and the tin It is characterized in that a diffusion layer of plating and nickel plating is formed.

In the production method according to claim 6, the cold-rolled steel sheet is subjected to nickel plating and tin plating sequentially on both sides, and further immersed in a bath containing sodium orthosilicate as a main component, or sodium orthosilicate. Electrolytic treatment is performed in a bath containing a main component to precipitate silicon hydrate on the surface, and then heat treatment is performed to diffuse the nickel plating into the cold-rolled steel sheet. It is characterized in that a diffusion layer is formed.

In these production methods, electrolytic treatment, 0. L～2 0 at a current density of AZ dm ^2, the total amount of electricity from 0.1 to 1 0 0 0 click one Ron Z dm precipitating ^second silicon hydrate ' In the step of forming a silicon hydrate layer, it is desirable to perform the A treatment and the C treatment alternately. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic manufacturing process diagram when a silicon hydrate is formed on the surface of a surface-treated steel sheet. FIG. 2 is a perspective view showing a state where the surface-treated steel sheet is fixed by applying a certain pressure. FIG. 3 is a perspective view showing a state in which two bonded test pieces are forcibly peeled off. BEST MODE FOR CARRYING OUT THE INVENTION

After cold-rolled steel sheet is nickel-plated, immersion treatment in sodium orthosilicate bath, or electrolytic treatment under specific conditions, maintains excellent appearance even after heat treatment, adhesion of steel sheets during heat treatment A nickel-plated steel sheet excellent in prevention can be obtained. Hereinafter, the present invention will be described in more detail. In the surface-treated steel sheet according to claim 1, a nickel-iron diffusion layer is formed on one side of a cold-rolled steel sheet, and a silicon oxide layer is further formed thereon. Alternatively, when the heat treatment temperature is low, the nickel plating layer may be formed on the uppermost layer (on the nickel-iron diffusion layer).

The nickel-iron diffusion layer preferably has a thickness of at least 0.5 m from the viewpoint of improving corrosion resistance, but a thickness exceeding 10 zz m is not economically preferable.

When a nickel plating layer is present, it is preferable that the thickness be at least 0.5 m from the viewpoint of further improving the corrosion resistance, which is not sufficient with the nickel-iron diffusion layer alone. The thickness exceeding is not economically preferable.

Although the layer of silicon oxide is 0. Preferable to l~3 mg / m ² is present as a silicon amount, because, if the lower limit is 0. Lmg Zm less than ^2, a heat treatment at sufficient adhesion prevention This is because it cannot be planned. On the other hand, an amount exceeding 3 mg / m ² is not preferable because the silicon oxide makes the appearance color tone of the surface-treated steel sheet white. In the present invention, since the silicon hydrate is precipitated from sodium orthosilicate, the silicon hydrate is extremely fine, and the color tone unique to the metal color can be maintained as it is.

Here, the silicon hydrate that precipitates from sodium orthosilicate is subjected to moisture treatment in a subsequent heat treatment step to form silicon oxide.

Further, the reason why the amount of silicon oxide deposited is defined as “as silicon amount” in the present invention is because of the convenience of analyzing silicon oxide. That is, the amount of silicon in the silicon oxide was specified by the fluorescent X-ray 'analysis method.

Silicon hydrate is nickel-plated on a cold-rolled steel sheet and then immersed in a bath containing sodium orthosilicate as a main component, or electrolyzed in a bath containing sodium orthosilicate as a main component and then heat-treated. It is formed by this. However, the electrolysis method has better adhesion efficiency than the immersion method.

Next, in the surface-treated steel sheet according to claim 1, a nickel-iron diffusion layer is formed on another surface, a nickel-tin tin diffusion layer is formed thereon, and a silicon oxide layer is further formed thereon. I have.

The nickel-iron diffusion layer preferably has a thickness of 0.5 to 10 zrn, and the nickel-tin tin diffusion layer thereon has a thickness of 0.05 to 5 m. further It is preferable that the silicon oxide layer thereon has a silicon amount of 0.1 to 3 mg_m ² .

The reason for forming the nickel-iron diffusion layer on the other side is the same as the reason described on one side above, but the reason for forming the nickel-tin tin diffusion layer is that the nickel-tin tin diffusion layer is extremely excellent in corrosion resistance. Because it is. That is, it has sufficient corrosion resistance to strong acids such as sulfuric acid, nitric acid, and hydrochloric acid. If the thickness of the nickel-tin tin diffusion layer is less than 0.05, the corrosion resistance cannot be sufficiently maintained, while if it exceeds 5 m, it is not preferable from an economic viewpoint. The reason for forming the silicon oxide layer is the same as above.

The surface-treated steel sheet of claim 2 is different from the surface-treated steel sheet of claim 1 in that nickel-tin diffusion layers are formed on both surfaces. The thickness of the nickel-tin tin diffusion layer is preferably 0.05-5. Thus, a surface-treated steel sheet having excellent corrosion resistance on both surfaces can be obtained. In other words, it can withstand the environment in which both sides come into contact with the strong acid or the like.

However, the surface-treated layer formed on the surface of the surface-treated steel sheet according to claim 1 or 2 may necessarily form a layer that cannot be clearly separated and distinguished. That is, the diffusion layer formed on the surface of the surface-treated steel sheet according to claim 1 or 2 is formed by heat treatment after plating, and the boundary of this diffusion layer gradually depends on the processing temperature and the processing time. It becomes unclear, and the base material iron and nickel plating (including tin plating if tin plating is applied) may intermingle with each other, and each component may form a diffusion layer with a concentration gradient .

Specifically, in the case of a nickel-iron diffusion layer, the iron-nickel diffusion layer consists of two components, iron and nickel. The iron concentration is higher on the side closer to the base material (iron), and the nickel concentration is higher on the upper layer (surface). It is a layer with a high gradient.

又 In addition, if the heat treatment temperature is increased or the time is increased, a three-component diffusion layer of nickel, tin, and iron may be formed. In this case, the iron near the base material (iron) In the middle layer, the nickel concentration is high, and in the upper layer (surface), the tin concentration is high, forming a diffusion layer with a gradient.

As a means for forming a nickel-tin tin diffusion layer, there is a method in which nickel plating and tin plating are applied to a substrate in an overlapping manner, and then heat treatment is performed. In addition, as a means for forming the iron-nickel-tin alloy layer, there is a method in which nickel plating and tin plating are repeatedly applied to a substrate, and the subsequent heat treatment is performed at a high temperature or performed for a long time. is there.

In the present invention, the nickel-tin tin diffusion layer is formed by applying a tin-nickel alloy plating to the substrate, as described above, in addition to applying a tin plating after nickel plating to form a two-layer plating layer and then performing a heat treatment. It can also be formed by heat treatment.

As the cold-rolled steel sheet, usually, a steel sheet of low-carbon aluminum killed steel is suitably used. Cold-rolled steel sheets made from non-aging low-carbon steel with the addition of niobium, boron and titanium are also used. Usually, the cold rolled, electrolytically cleaned, annealed, and temper rolled steel sheet is used as the plating original sheet, but the cold rolled steel sheet may be used as the plating original sheet. In this case, after nickel plating is performed after cold rolling, recrystallization annealing of the steel base and thermal diffusion treatment of the nickel plating layer can be simultaneously performed.

As the nickel plating bath, any of known plating baths such as a watt bath, a sulfamic acid bath, and a chloride bath can be used in the present invention. Further, the types of plating include matte, semi-gloss, and glossy, but matte or semi-glossy other than glossy to which a sulfur-containing organic substance is added is preferably used in the present invention. I'll

(With tin plating)

The bath composition includes an acidic bath and an alkali bath which are usually used, and a stannous sulfate bath or a phenolsulfonic acid bath is preferably used.

In addition, the method of tin plating is generally performed in the steps of degreasing, pickling, tin plating, reflow (tin melting treatment), and chemical treatment.

The plated steel sheet is subjected to immersion treatment or electrolytic treatment in a sodium orthosilicate solution. Preferably, the sodium orthosilicate solution has a concentration of 1 to 7%, more preferably 2 to 4%.

When the concentration is 1% or less, the amount of silicon hydrate precipitated on the steel sheet is small, and in the subsequent heat treatment step, the required amount of silicon oxide of 0.1 lg Zm ² or more is obtained. In addition, when heat treatment is performed, the adhesion between the steel sheets tends to occur.

In addition, when the electrolytic treatment is performed, there is a problem that a treatment voltage is increased. On the other hand, if the concentration is 7% or more, the amount of sodium orthosilicate solution taken out of the treatment tank as the steel sheet moves increases, which is uneconomical. In addition, handling of the treatment bath becomes dangerous, which is not preferable.

The total amount of electricity when the electrolytic treatment for attaching silicon hydrate is performed is preferably from 0.1 to 100 Coulomb dm ² .

Total amount of electricity to zero. 1 for less than click one Ron / dm ^2, poor adhesion efficiency onto dark-out steel sheet silicon hydrate, as the silicon amount required 0. Lg Zm ² than on A large amount of silicon oxide cannot be obtained, and the steel sheets tend to adhere to each other during heat treatment.

'On the other hand, even if the total amount of electricity is increased to 100 Coulombs Z dm ² or more, no more silicon hydrate will be precipitated on the steel sheet, and economic waste will occur.

The nickel-plated steel sheet that has been treated with the above-mentioned sodium orthosilicate solution and wound into a coil is subjected to box annealing at a temperature of about 500 to 700 ° C for several hours or more. By heating, diffusion layers of various thicknesses can be formed. This thickness can be adjusted by changing the heat treatment temperature and time.

FIG. 1 is a schematic manufacturing process diagram in a case where a nickel-plated steel sheet is subjected to electrolytic treatment in a bath containing sodium orthosilicate as a main component to precipitate silicon hydrate on the surface thereof.

For the electrolytic treatment, any of the horizontal processing tanks shown in FIGS. 1 (a) and (b) or the vertical processing tanks shown in FIGS. 1 (c) and 1 (d) may be used.

'' As a method of forming a precipitate layer of silicon hydrate on the surface of a nickel-plated steel sheet, first, as shown in Fig. 1 (a) or (c), C treatment (the steel sheet side is used as a cathode) is performed. After that, there is a method of A treatment (steel plate side anode) in the next step.

Further, as shown in FIG. 1 (b) or (d), a method of first performing A treatment and then performing C treatment can also be used.

Any of the above treatment methods can clean the surface of the plated steel sheet during this treatment, and thus is effective as a method for depositing a large amount of silicon hydrate on the surface of the Nigel plated steel sheet.

In particular, the process of first performing the C treatment and then performing the A treatment It is excellent in the efficiency of precipitating silicon hydrate on the surface of the plate.

Furthermore, a large number of processing tanks and electrodes are provided, and C treatment → A treatment or A treatment

→ A process of repeating the C process a plurality of times may be performed.

Furthermore, in the above-mentioned multiple repetition processes, C process-A process-A. processing

, Or A processing-C processing-As in A processing, the polarity of the beginning and end may be the same.

(Heat treatment)

The heat treatment for forming the diffusion layer can be performed in a non-oxidizing or reducing protective gas atmosphere (for example, 6.5% hydrogen, the balance of nitrogen gas, and a protective gas with a dew point of 60 ° C). It is preferable to prevent film formation. The heat treatment temperature must be 300 ° C or higher.

As a method of heat treatment, there are a box annealing method and a continuous annealing method. In the present invention, either method may be used. In the continuous annealing method, a high-temperature, short-time treatment, that is, 600 to 850 ° C for 30 seconds to 5 hours The heat treatment conditions of 450 to 650 ° C. for 5 to 15 hours are preferred in the box annealing method.

(Example)

(Example 1)

Cold-rolled steel plate (substrate) was washed with alkaline electrolytic degreasing (caustic soda 30 gZl, 5 A / dm ²

(Anodic treatment) X 10 seconds, 5 A / dm ² (Cathode treatment) X 10 seconds, bath temperature 70 ° C), sulfuric acid pickling (sulfuric acid 50 gZl, bath temperature 30 ° C, immersion for 20 seconds) After that, nickel plating was performed on both sides of the substrate under the following conditions.

Bath composition Nickel sulfate 320 g.

Nickel chloride 40 g.

Boric acid 30 g.

0.5 g of sodium lauryl sulfate.

Bath temperature 55 ± 2 ° C

PH 4.1 to 4.6

Stir Air stir

1 OA / dm ² Anode: Nickel pellet

Under the above conditions, several types of nickel plating having different thicknesses were prepared by changing the electrolysis time. Following the nickel plating, tin plating was applied to one surface under the following conditions.

Bath composition: stannous sulfate 30 gZl (S ++)

Phenylsulfonic acid 60 g 1

Ethoxylated α-naphthol 5 g 1

Bath temperature: 50 ± 2 ° C

Current density: 2 OA / dm ²

Anode: Tin plate

The bath composition for tin plating may be any of a commonly used acidic bath or alkali bath, but in the present invention, a stannous sulfate bath or a phenolsulfonic acid bath is suitably used. The plating thickness was controlled by changing the electrolysis time.

Next, immersion treatment or electrolytic treatment was carried out under various conditions in a sodium orthosilicate solution.

[Electrodeposition of Silicon Hydrate in Sodium Orthosilicate]

• Treatment bath Sodium orthosilicate 30 1

'Bath temperature 50 ± 5 ° C

• In the case of immersion treatment, the immersion time was varied to adjust the amount of adhesion. For electrolytic treatment, the current density was 5AZdm ^2, the quantity of electricity and polarity were changed variously to prepare a different processing steel sheet deposition amount of silicon hydrate.

(Example 2)

The difference from the first embodiment is that after nickel plating was applied to both surfaces, a nickel-tin alloy was applied to one surface under the following conditions. Other points are the same as in the first embodiment.

Bath composition: Stannous chloride (SnC 1 _₂ · 2H ₂ 〇) 50 g / 1

Nickel chloride _{(N i C 12 · 6H 2} 0) 300 g / 1 sodium fluoride (NaF) 30 g / 1 acid fluoride Anmoniumu _{_{(NH 4 HF 2) 35 g}} / 1 Bath temperature: 65 ° C

2.5 A / dm ²

P H 2.5

Anode Nickel-tin alloy anode containing 28% tin

The nickel-tin alloy plating bath may be a chloride monofluoride bath or a pyrophosphate bath. Table 1 summarizes the results.

A sample with a size of 10 Omm X 3 Omm was cut out from the treated steel sheet obtained as described above, and the two specimens treated under the same conditions were overlapped so that the treated surfaces were in contact as shown in Fig. 2. Combine them into a laminated body 1 and apply 4 sets of bolts 4 and nuts 5 to each test piece with a torque wrench via a pressure receiving plate 2 and a securing plate 3 that are placed in contact with the top and bottom of the laminated body. It was fastened and fixed so that the same lashing force of Zmm ² acts. The temperature of the thus secured test piece was changed in a protective gas atmosphere consisting of 6.5% hydrogen and the balance of nitrogen at a temperature of (550 to 700 ° C) for different times. (1 to 10 hours) Heat treatment was performed.

After the heat treatment, as shown in Fig. 3, one end of the bonded surface of the two bonded test pieces is forcibly peeled off, and the two ends are T-shaped so that both peeled ends are fixed to both chucks of the tensile tester. Into a tensile test piece. The tensile test piece was peeled off by a tensile tester, the adhesion strength at which peeling started was measured, and the degree of adhesion of the test piece by heat treatment (adhesion prevention) was evaluated based on the following criteria.

〇: Good (peeled off with a tension of less than 3 kgf)

X: defective (peeled off with a tension of 3 kgf or more)

Table 1 shows the processing conditions and evaluation results for the samples. Table 1 Plated thickness Annealing with lulycaic acid solder solution During annealing

IX m Material with different silicate precipitation conditions

No Ni Sn Type Electrolytic treatment Total electricity amount Temperature / time adhesion 1 grease / order J Λ / fjm ² (hour) Prevention

1 surface 2.1

Immersion 0.41 550 10 〇 Back 1.9 0.3

2 Surface 2.0

Electrolysis 100 1.05 550 10 〇 Back side 2. 0 1. 0

3 surface 2. 5 c Sho锞_m

Electrolysis → A treatment 100 1.14 550 10 裏面 Back side 1.5 1.5

Book

4 Surface 4.9

1 Electrolysis C treatment 1 5 0.50 600 8 裏面 Back side 1.80.5

Start 5 Front 4 ― Electrolytic A treatment 250 1.70 600 8 〇 Back 1 0.4

6 surface 3. 5 2. 5 ^c processing

Ming Electrolysis 250 1.84 700 1 裏面 Back side 4. 6 1.2 → C treatment

7 Surface 15 5 C processing → A L processing

Electrolysis 1000 2.35 700 1 〇 Back side 10 2 → A treatment

8 Surface 10 4 A treatment

Electrolysis 1000 2.23 700 1 〇 Back side 8 2 → C treatment

9 Surface 0.5 0.53

Immersion 0.39 600 1 2 裏面 Back side 3.2 0.03

10 Surface 0.5 0.5 0.03

Electrolysis A treatment 200 1.32 600 12 裏面 Back side 3.2 0.03 → C treatment

1 1 Surface 0.5 0.53

Electrolytic C processing 200 1.46 600 12 裏面 Back side 3.2 0.03 → A processing

1 2 Surface 1.9 0.4

Immersion 0.442 650 6 裏面 Back side 2.3 0.09

13 Surface 1. 9 0.4

Electrolysis A treatment 50 0.85 650 6 sta sta 2. 3 0.09 — C treatment

14 Surface 1.9 0.4

Electrolytic C treatment ήπ 50 0.93 650 6 裏面 Back side U.09 ^→ Αtreatment

1 5 Surface 2.0.0 0.31

550 10 X ratio Back 2.3

Comparison 16 Surface 1.9 0.43

600 8 X back side 4.7

An example

1 7 Surface 0.5 0.5 0.1

650 8 X back side 2. 1 0.08

1 8 Surface 3.5 2.21

700 1 X back side 4.5 0.72 As shown in Table 1, in the surface-treated steel sheet of the present invention, adhesion of the steel sheets during heat treatment hardly occurs.

As a comparative example, heat treatment was performed without forming any silicon oxide layer on the nickel-plated steel sheet, but adhesion between the steel sheets occurred.

Industrial applicability

The surface-treated steel sheet of the present invention has excellent corrosion resistance and also has excellent anti-adhesion properties during heat treatment. That is, even when the plating treatment is performed while the surface-treated steel sheet is wound in a coil shape, adhesion between the steel sheets does not occur.

Claims

The scope of the claims

1. Nickel plating on both sides of cold-rolled steel sheet, then tin plating only on one side, and then immerse in a bath containing sodium orthosilicate as a main component, or use sodium orthosilicate as a main component. A surface-treated steel sheet characterized in that silicon hydrate is precipitated on the surface by electrolytic treatment in a bath to be heated, and then heat treatment is performed to diffuse the adhesion.

2. Both sides of the cold-rolled steel sheet are nickel-plated with a thickness of 0.5 to 10 m, then only one side is coated with a tin with a thickness of 0.05 to 5 m, and sodium orthosilicate is further added. as the amount of silicon on the surface by electrolytic treatment in a bath consisting mainly of one or Orusokei sodium immersed in a bath consisting mainly 0. precipitating silicon hydrate l~3 mg / m ^2, After that, a heat-treated steel sheet is characterized in that the adhesion is diffused.

3. Nickel plating and tin plating are sequentially applied to both sides of the cold-rolled steel sheet, and then immersed in a bath containing sodium orthosilicate as a main component, or electrolyzed in a bath containing sodium orthosilicate as a main component. A surface-treated steel sheet characterized by being subjected to a treatment to precipitate silicon hydrate on the surface, and then to a heat treatment to diffuse the nickel plating and tin plating.

4. Both sides of the cold-rolled steel sheet are plated with nickel to a thickness of 0.5 to 10 xm, then both sides are tin-plated to a thickness of 0.05 to 5 m, and then sodium orthosilicate is applied. as the amount of silicon on the surface by electrolytic treatment in a bath consisting mainly of one or Orusokei sodium immersed in a bath consisting mainly 0. precipitating silicon hydrate l~3 mg / m ^2, Thereafter, a heat treatment is performed to diffuse the nickel plating and tin plating.

5. Both sides of the cold-rolled steel sheet are plated with nickel, and then only one side is tin-plated. Electrolytic treatment in a bath to perform precipitation of silicon hydrate on the surface, followed by heat treatment to diffuse the nickel plating into the cold-rolled steel sheet and to reduce the tin plating and the nickel plating. Characterized by forming a diffusion layer, Manufacturing method of surface treated steel sheet.

6. Nickel plating and tin plating are sequentially applied to both sides of the cold-rolled steel sheet, and then immersed in a bath containing sodium orthosilicate as a main component, or electrolytically treated in a bath containing sodium orthosilicate as a main component. To precipitate silicon hydrate on the surface, and then heat-treat to diffuse the nickel plating into the cold-rolled steel sheet and form a diffusion layer of the tin plating and the nickel plating. Manufacturing method of surface-treated steel sheet.

7. The method according to claim 5, wherein the electrolytic treatment precipitates a silicon hydrate having a total electric quantity of 0.1 to 100 Coulomb Z dm ² at a current density of 0.1 to ²⁰ AZ dm ² . Production method as described.

8. The method according to any one of claims 5 to 7, wherein in the step of forming the silicon hydrate layer, A treatment and C treatment are alternately performed.