JPH02129395A - Flaw resistant nickel-plated steel sheet and production thereof - Google Patents

Abstract

PURPOSE:To produce a nickel-plated steel sheet excellent in flaw resistance and workability by forming a nickel-plated layer of specified build-up amount on the double sides of the steel sheet and furthermore plating Ni-P alloy having specified composition at specified build-up amount and thereafter performing specified heat-treatment. CONSTITUTION:Ni plating and/or an Ni-Fe alloy layer of 5-45g/m<2> buildup amount are formed on both the surface and the rear of a steel sheet. The Ni-Fe alloy layer is preferably regulated to 0.2-10mum thickness. Furthermore Ni-P alloy plating contg. 5-15wt.% P is performed at 1-18g/m<2> Ni build-up amount on the upper layer of at least single side. This Ni plating and Ni-P alloy plating are preferably performed by electrolytic treatment. Then the steel sheet after plating treatment is heat-treated at 450-800 deg.C for 0.2-900 minutes and thereby the adhesive properties of both plated layers are enhanced and the Ni-P alloy layer is cured. Thereby the Ni-plated steel sheet is obtained which is high in hardness and flaw resistant while holding excellent workability and furthermore has corrosion resistance after work in combination therewith.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a scratch-resistant (= J-plated) Ni-plated steel sheet and its manufacturing method, and more specifically to stationery such as dry battery cases, electronic + A month, binders, etc. This invention relates to a scratch-resistant Ni-plated steel sheet suitable for T4 material and a method for producing the same.

(1; Technology from the past) Conventionally, in order to improve the inefficiency of so-called barrel plating, which involves processing f&Ni plating, and the non-uniformity of the plating process, Ni-plated steel that has been pre-plated with Ni has been used. but,
In the case of the Ni-plated 1-A strip in which Ni is plated on the "M" part, the adhesion of the plating layer is insufficient, and the plating layer often tends to peel off in the "A"-2 part, which has been a problem. As a countermeasure to this problem, a method has been sought to ensure adhesion of the plating layer by heat-treating the Ni-plated steel sheet after Ni plating to form a Ni--Fe alloy layer between the Ni layer and the steel sheet.

(For example, Japanese Patent Application Laid-open No. 61-235594) On the other hand, heat treatment is also effective for corrosion resistance, especially for overhang,
The improvement is remarkable in highly processed parts such as pattern processing.

The reason for this is that the Ni plating layer as plated is hard, has poor workability, and is prone to cracking, whereas after heat treatment, the plating strain is released and the Ni plating layer softens, increasing its ductility and making the coating more ductile. In addition, the Ni-Fe alloy layer itself at the interface formed also functions as a pond that improves the adhesion of the plating layer and alleviates the potential gradient in the local battery as described above.
This is probably because it contributes to improving corrosion resistance, especially post-processing corrosion resistance.

[Problem to be solved by the invention]

However, in the above conventional techniques, as a result of the Ni plating layer being softened by heating as described above, it is inevitable that the scratch resistance will deteriorate.

Furthermore, if the scratch resistance is impaired, the plating layer is more likely to be damaged during transportation or processing, and as a result, the corrosion resistance as a whole tends to deteriorate.

In particular, when used in dry cell cases, etc., deep scratches may occur and Fe
was exposed, causing pitting corrosion, which could even lead to leakage of electrolyte and even the risk of destroying surrounding electronic circuits.

[Purpose of the invention]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a Ni-plated steel sheet that has excellent workability, scratch resistance, and post-processing corrosion resistance, and a method for manufacturing the same.

[Structure of the invention]

According to the present invention, it has a Ni plating layer and/or a Ni-Fe alloy layer with an adhesion m5 to 45 g/m2 on both the front and back surfaces, and further has a P content of 3 to 15% by weight on the upper layer of at least one side, and a Ni adhesion amount of 1 A scratch-resistant Ni-plated steel sheet characterized by having a Ni-P alloy layer of ~18 g/m'' and Ni of ~45 g/~2 m attached to both the front and back surfaces of the steel sheet.
Plating is applied, and the upper layer of at least one side contains P (m3).
After applying Ni-P alloy plating with ~15% overlap and Ni adhesion fff site l-10g/m2, (4,50~800)
'CX (0,2~900) min.

Provided is a method for producing a scratch-resistant Ni-plated steel sheet, characterized in that the heat treatment is not performed.

The present invention will be explained in detail below.

Normal steel cold-rolled steel sheets are usually used as general-purpose steel sheets. Among these, cold-rolled steel sheets based on low carbon Aλ killed steel continuously cast materials are mainly used.

Also used are cold-rolled steel sheets made from ultra-low carbon steel containing C: 0.003% by weight or less, or from non-aging steel to which Nb, Ti, etc. are added.

Further, a Cr-containing steel or stainless steel plate containing 3 to 18% by weight of Cr (which may also contain about 1 to 10% by weight of Ni) is preferably used.

There are sulfamic acid baths, fluoride baths, chloride baths, etc., and any of these baths may be used in the present invention.

In addition, as a pretreatment for Ni plating, alkaline degreasing < Wi
(including degreasing), organic solvent degreasing, pickling (soaking in sulfuric acid, hydrochloric acid, nitric acid, etc., electrolysis may also be used), and washing with water.

For Ni plating itself, straw H valley and sulfamic acid bath are often used industrially. Although there is an electroless method, in the present invention, the electrolytic method (cathode treatment) is adopted because it is easier to control the plating thickness and control the bath than electroless treatment. Usually in this case the current density is 3-80 A/d ~
It is about 2.

Further, the pH of the bath is preferably in the acidic range of 3.5 to 5.5. The bath temperature is about 40-60°C.

Note that it is not desirable if the bath contains a brightener containing S, such as a naphthalene sulfonate, because the plating layer will become brittle in the subsequent heat treatment step. However, brighteners such as butynediol, coumarin, ethylenecyanohyperinyl-1ζphosphorus, etc. can be applied to the present invention without any problems.

The amount of Ni deposited in the Ni plating layer is preferably in the range of 5 to 45 g/m", preferably 18 to 36 g/ln2. If the deposit does not reach 5 g/m", the surface of the steel plate is not sufficiently covered. If the amount exceeds 45 g/rn2, the effect of the present invention will be saturated, which will be uneconomical, and the product will lose its price competitiveness.

Ni-PΔ gold plating Ni-P alloy plating is usually applied directly to the Ni-plated bare surface after washing with water, but pretreatment such as degreasing, washing with water, washing with pickling, and washing with water may also be performed.

The Ni-P alloy plating method applied on the Ni plating layer is
Either the electroless Ni--P alloy plating method, which is widely adopted for plating magnetic disks and the like which dislikes plating distortion, or the electrolytic Ni--P alloy plating method, which allows easy control of the amount of plating, may be used.

The bath used in the electroless Ni--P alloy plating method is generally an acidic bath using hypophosphorous acid 3B as a reducing agent. The bath composition of this acidic bath is 20 to 50% nickel sulfate.
g/2, nickel chloride 15-30 g/2,
It contains 20 to 50 g/λ of sodium hypophosphite, and further contains organic additives such as sodium acetate and succinic acid, citric acid, malic acid, or their sodium salts.

A relatively high bath temperature of 80 to 95°C is used. I)
) (is in the range of 4.3 to 5.5. In the present invention, the amount of deposited Ni-P alloy plating layer is in the range of 1 to 18 g/m2, preferably 3 to 10 g/m" as Ni. In addition, the Ni-P alloy plating layer in the present invention is a Ni plating layer containing 3 to 15 ffim% of P, and the amount of Ni is 1 to 18 g/m2 as Ni.
must be within the range. The desired scratch resistance cannot be achieved unless the amount of Ni deposited reaches 18g/m2.
If it exceeds m2, it will be difficult to ensure the workability of the plating layer,
This is because it is uneconomical.

In addition, if the P component in the Ni-P alloy plating layer is less than 3% by weight, a sufficient hardening effect of the upper plating layer cannot be obtained, and 15
This is because if the Ni--P alloy plating layer exceeds the weight percentage, the plating stress becomes extremely high, and the adhesion of the plating layer becomes tfM.

The electroless Ni--P alloy plating method requires a lot of time to obtain the same amount of deposition. That is, since it is not possible to continuously plate a steel strip at high speed as with electrolytic treatment, the cut steel plate is immersed in the plating bath. This immersion time is 40 seconds ~ 2
5111 in, degree.

After completing the Ni-P alloy plating, the steel plate is taken out, washed with water, and dried. No particular post-processing is performed.

On the other hand, the plating bath used in the electrolytic Ni-P alloy plating method is as follows.

When the present invention is carried out industrially, electrolytic Ni-P alloy plating is more advantageous than electroless Ni-P alloy plating, which allows plating to a predetermined thickness in a shorter time.

Industrial baths for electrolytic Ni-P alloy plating include nickel sulfate, nickel chloride-based baths, or nickel sulfamate baths containing phosphorous acid, phosphoric acid, hypophosphorous acid, and/or phosphorous acid as a P source. Phosphite, Phosphate JM
A bath to which , hypophosphite, etc. are added is usually used.

A typical plating bath mainly containing nickel sulfate and nickel chloride is, for example, 100 to 350 g/J of nickel sulfate, 10 to 50 g/J of nickel chloride, and 5 to 40 g/J of phosphorous acid to ρ.
g/j! Or further phosphoric acid 30-50 cc/
1 was added. In this swamp? 6 warm 50-70
Current density at 'C, pH 0, 6-1.5 3-
15 A/d m” cathodic electrolysis treatment.

As for the η of sulfamate bath,
The following are described in Publication No. 038 and the like.

That is, 200 to 800 g of nickel sulfamate
/λ, nickel chloride 5-20g/j! , hydric acid 30
~60 g/l with sodium hypophosphite 0.05-20 g/l as P source, or sodium phosphite
It is a swamp containing 0.05-20g/or. The cathode electrolytic treatment conditions performed using this bath are: bath temperature 60-70°C;
p) i5-5.5, current density 10-100A/dm2
It is.

In addition, since the cathodic deposition efficiency of electrolytic Ni--P alloy plating is low, the amount of nickel ions dissolved from the soluble Ni anode in the bath increases. Furthermore, phosphorous acid and hypophosphorous acid added as a P source are oxidized at the anode to become phosphoric acid, and the free acid concentration increases. Therefore, the bath composition and pH tend to fluctuate, and the plating conditions tend to deviate from the proper plating conditions. To prevent this, the anode area should be reduced to l! It is necessary to appropriately reduce the a-pole value.

The amount of plating deposited in electrolytic Ni--P alloy plating is the same as the range described for electroless Ni--P alloy plating.

Further, as a plating treatment method, a method similar to that described for electroless Ni-P alloy plating is used.

Yamametssen・ ■Plating The Ni plating and Ni-P alloy plating described above are applied to one or both sides of a steel plate, depending on the application.

For example, when used in a dry battery case such as an alkaline manganese battery or a Ni-Cd battery, the inner surface of the bottomed cylindrical case has only a Ni plating layer, and the outer surface has a Ni plating layer.
As an i+Ni-P alloy plating layer, it can deal with other scratches during the working process. Also, for applications such as binders, stationery, metal tableware, etc., those coated with Ni plating + Ni-P alloy plating on both sides are used.

After applying two layers of Ni plating and NIP alloy plating on a steel strip plate as described above, heat treatment is performed. This heat treatment improves the adhesion of the plating layer by forming a Ni-Fe alloy layer under the Ni plating, and secondly, it improves the adhesion of the plating layer.
This is to harden the i-P alloy layer and improve its scratch resistance and post-processing corrosion resistance at the same time. The heat treatment is a type of annealing treatment in which the material is heated in a non-oxidizing atmosphere gas at a temperature of (450 to 800)'C1 soaking time of (0.2 to 900) min. As a specific method, in the case of a cut plate, a method is used in which heat treatment is performed in a box-shaped annealing furnace at a temperature of 450 to 650° C. and a soaking time of (Go to 900) min.

In the case of a steel strip coil, there is a continuous annealing method in which the steel strip coil is continuously passed through and heat treated, in addition to the case where the steel strip coil is heat treated in a box-type annealing furnace like the above-mentioned cut plate.

In the continuous annealing method, the temperature is 600 to 800℃ and the soaking time is 0.
, 2 to 5) min, heat treatment is performed.

In either case, the heat treatment is performed in a non-oxidizing atmosphere.

Examples of the non-oxidizing gas in the present invention include various modified gases,
That is, an endothermic or exothermic gas is used. These include, for example, HN X gas, DX gas, NX gas, RX gas,
There are AX gases, etc. Besides that, hydrogen only or H
Inert gas such as e, Ne, Ar, etc., vacuum, etc. can also be used.

The Ni-Fe alloy layer is formed as a result of heat treatment. The thickness is determined by the heating temperature and heating time, but Ni-F
The thickness of the e-alloy layer must be in the range 0.2 μrn to 10 μm 11 . The thickness of the Ni-Fe alloy layer is 0.2
If it does not reach 7zm, no improvement in plating adhesion can be obtained, and on the other hand, if it exceeds 10/1 ITI, the entire Ni plating layer becomes a Ni-Fe alloy layer, and the Fe in the plating surface layer becomes
This is because too high a proportion causes deterioration of corrosion resistance.

That is, in the present invention, it is preferable that the Ni-Fe alloy layer does not reach the full thickness of the Ni layer and that even a small amount of the pure Ni layer remains.

In order to make the thickness of the Ni-Fe alloy layer 0.2~1011rn, the heat treatment conditions were as described above (450~800rn).
℃X (0,2~900) min. Heating temperature is 450℃ without groove and heating time is less than 900m
If the temperature exceeds 800° C., the necessary alloy layer will not be formed, and if the temperature exceeds 800° C., the crystal grains of the steel sheet will become coarse and the mechanical properties will deteriorate, making it unusable.

Further, if the thickness is less than 0.2 m1n, the necessary alloy layer will not be formed even if the temperature is increased.

The method up to the heat treatment after two-layer plating of nickel plating and Ni--P alloy plating has been described above.

In the present invention, the purpose of the present invention is achieved through the steps up to the heat treatment, but depending on the intended use, after the heat treatment, it may be necessary to improve mechanical properties such as preventing buckling or to impart a desired surface finish. In some cases, skin pass rolling is performed with a roughening ratio of about 0.5 to 5%.

[Action of the invention]

According to the present invention, a nickel-plated steel sheet with excellent scratch resistance can be obtained by heat-treating the two-layer plating of Ni plating and Ni-P alloy plating.

Under the heat treatment conditions of the present invention, Fe is added to the Ni-plated lower layer.
A Ni-Fe alloy layer is formed by solid-state diffusion of Ni and has a thickness of 0.2 to 10 μm.

As a direct effect of forming the Ni-Fe alloy layer, it is possible to improve the adhesion between the steel strip of the object to be plated and the Ni plating layer, and to improve the workability due to the improved ductility of the Ni plating layer. Ni
Regarding the thickness of the -Fe alloy layer, it is not necessarily necessary to make all of the Ni plating layers a Ni--Fe alloy layer. Temperature at which Ni plating layer softens and recrystallizes: 450°C x Heating time: 6
In the case of 0 m i old, the thickness of the Ni-Fe alloy layer is 0.
It is about 2 μm. Therefore, in this case, the Ni plated layer is
There are two layers: a lower Ni--Fe alloy layer and a softened and recrystallized upper Ni layer. Among the heat treatment conditions of the present invention, heating temperature 7
50°C x soaking time 360m1n, when closed, N
The thickness of the i-Fe alloy layer is 6 μm, and the entire Ni plating layer becomes the Ni-Fe alloy layer. In this case as well, the Ni
The same improvements in corrosion resistance and workability as in the case where the plating layer has a two-layer structure of the Ni-Fe alloy layer and the softened jtJiJ7ji can be obtained.

On the other hand, when softening recrystallization is completed, the plating surface layer becomes soft and scratch resistance is impaired. Depending on the handling method, the corrosion resistance may be deteriorated due to poor scratch resistance due to the softening effect, rather than the corrosion resistance improvement effect obtained by heat treatment. In fact, when we measure the surface hardness of a plating layer that has been softened and recrystallized, it is Hv 300-350 for AS plated, whereas it is Hv 150-200 after heating above 450°C where softening and recrystallization occurs.
There is a tendency for the surface layer to soften considerably and for the scratch resistance to deteriorate.

As a means to solve this problem, in the present invention, Ni-P alloy plating is applied on the Ni plating layer and at the same time, a Ni-Fe alloy layer is formed on the lower Ni plating layer by applying a heat treatment to the upper layer. The present invention provides a method for simultaneously thermosetting Ni-P alloy plating layers.

Generally, methods for hardening the surface layer through surface treatment include gas carburizing as a diffusion treatment, nitriding treatment, Ni-B alloy plating, and composite plating with the addition of boron carbide, etc., but none of these methods The processing method is complicated, expensive, and impractical.

The advantages of applying Ni-P alloy plating on the Ni plating layer as in the present invention are as follows: 1) Ni-P 2) The alloy plating layer hardens significantly, and 2) the lower Ni plating layer and the upper N layer harden due to heat treatment.
Interdiffusion of i-P alloy plating layer does not occur, immediately, N
Properties can be improved by heat treatment for each of the i plating layer and the Nj-P alloy plating layer separately, 3) No pretreatment is required when applying Ni-P alloy plating after Ni plating, etc. can be mentioned.

The hardness of the Ni-P alloy plating layer is Hv500-600 when As Plated, but it can be reduced to Hv90 by precipitation hardening of Ni3P by heat treatment.
With a hardness of 0 to 1000, it hardens to the same level as hard Cr plating.

〔Effect of the invention〕

By implementing the present invention, the above objects are achieved.

That is, a Ni-plated steel sheet and a method for manufacturing the same are provided that have both excellent workability, scratch resistance, and post-processing corrosion resistance.

〔Example〕

The present invention will be explained in more detail below using Examples.

(Example 1) After performing alkaline electrolytic degreasing and sulfuric acid immersion pickling on an annealed low-carbon aluminum-killed steel thin steel sheet having a thickness of 0.25 mm, Ni plating was performed under the following conditions.

? Bath composition Nickel sulfate 350g/λ Nickel chloride 45g/l Boric acid 30g/l Sodium lauryl sulfate 0.5g/J Bath temperature
50° C. pH 4.2 Current density 10 A/dm2 The amount of Ni deposited in the Ni plating was 8.0 g/rn2.

Next, electrolytic Ni-P alloy plating was performed under the following conditions.

Bath composition Nickel sulfate 150g/l Nickel chloride 80g/, uSonic acid
30g/bath temperature 5
0℃ pH0.6 Current density 3 A/d m2Ni
-The amount of P alloy plating is 1.4g/m2 as Ni,
The P content in the same plating layer was 12% by weight.

After electrolytic Ni-P alloy plating, the steel plate was washed with water and dried.

It should be noted that plating was applied to one side in all cases, and the same applies to other examples and comparative examples. ).

Then with 1426% HNX gas (dew point -10°C),
Heat treatment was performed at a heating temperature of 520° C. and a soaking time of 360 m1n, and temper rolling was performed at an elongation rate of 1.2%.

(Example 2) Using the thin steel sheet described in Example 1, Ni plating was performed under the same conditions as in the example. The amount of Ni deposited is 43.0g/r
It was set as n2.

Next, electrolytic Ni-P alloy plating was performed under the following conditions.

Bath composition Nickel sulfate 150g/l Nickel chloride 40g/l Phosphorous acid 5g/l? Tani On
Current density at 65°C: 15 A/dm The amount of Ni-P alloy plating deposited was 10.0 g/m2 as Ni, and the P content in the same plating layer was 4% by weight. After electrolytic Ni-P alloy plating, the steel sheet was washed with water, dried, heat treated under the same conditions as in Example 1, and then temper rolled.

(Example 3) After degreasing and pickling an unannealed thin steel plate of slow aging ultra-low carbon aluminum killed steel with a plate thickness of 0.25 mm, N was applied under the following conditions.
i-plated. The amount of Ni deposited is Ni 18. Og
/m2.

? Bath composition Nickel sulfamate 400g/ffi Nickel chloride 20g/J! Boric acid
30g/l Sodium lauryl sulfate 0.5g/
l Bath temperature: 50°C pH: 4.0 Current density: 15 A/dm2 Next, immediately after washing with water, electrolytic Ni-P alloy plating was performed under the following conditions.

? Bath composition Nickel sulfamate 350g/J Nickel chloride
20g/λ boric acid 2
5g/l phosphorous acid 40g/λ bath temperature
45℃ pH 1,2 Current density 3A/dm2Ni-P
The amount of alloy plating deposited was 5.3 g/m2 as Ni, and the P content in the same plating layer was 8% by weight.

After electrolytic Ni-P alloy plating, the steel plate was washed with water and dried.

Next, heat treatment was performed at a heating temperature of 750°C and a soaking time of 1 m1n, and further temper rolling was performed at a roughening rate of 1.5%.

(Example 4) The same 86M plate as described in Example 3 was subjected to alkaline electrolytic degreasing and sulfuric acid immersion pickling, and then Ni plating and electrolytic Ni-P alloy plating were applied under the same conditions as Example 3. . However, the amount of Ni deposited in Ni plating is 27.1 g/m2, and the amount of deposited in electrolytic Ni-P alloy plating is 3.5 g/m2 as Ni.
g/m2, and the P content in the same plated layer was 8% by weight. After electrolytic Ni-P alloy plating, the steel plate was washed with water and dried, then heat treated under the same conditions as in Example 3, and temper rolled.

(Example 5) The same thin steel sheet as described in Example 1 was subjected to alkaline electrolytic degreasing and sulfuric acid immersion pickling, and then Ni plating was performed under the same conditions as in Example 1. However, the amount of Ni deposited in the Ni plating was 17.5 g/m2.

Next, electroless Ni-P alloy plating was performed under the following conditions.

Bath composition Nickel sulfate 25g 71 Sodium hypophosphite 30g/λ Malic acid 3
0g/l Sodium succinate 5g/1
Lead nitrate 1.2mg/l bath temperature
90°C p) (4,5 Ni-P alloy plating deposition amount is 5.8g/Ni)
m2, the P content in the same plating layer was 11% by weight.

After the electroless Ni-P alloy plating, the steel plate was washed with water and dried.

Next, the heating temperature was 650°C and the soaking time was 480 +11 i.
n, heat treatment was performed, and temper rolling was performed with an elongation rate of 0.8%.

(Example 6) In Example 5, the amount of Ni deposited in Ni plating was 34.5 g.
/m2, the amount of Ni deposited by electroless Ni--P alloy plating was 15.8 g/m'', and the P content in the same plating layer was 11% by weight.

(Comparative Example 1) Using the 7fJ steel plate described in Example 1, Ni plating of 9.6 g/m'' was applied to Ni deposit 1 under the same conditions as in Example 1 of the present invention, followed by washing and drying. -P alloy plating and heat treatment were not performed.

(Comparative Example 2) Using the thin steel sheet described in Example 1, Ni plating was performed under the same conditions as in Example 1 of the present invention with a Ni deposition amount of 9.5 g/m2. Next, after washing with water and drying, in the same HNX gas atmosphere as in Example 1, the heating temperature was 500°C, the soaking time was 120 m1n,
Heat treatment was performed, and after cooling, temper rolling was performed with an elongation rate of 1.2%.

(Comparative Example 3) In Comparative Example 1, the amount of Ni deposited in Ni plating was 25.2.
g/m2, and the heat treatment was performed at a heating temperature of 550° C. and a soaking time of 600111 in.

(Comparative Example 4) In Comparative Example 1, the amount of Ni deposited was 36.7 g/m2,
Furthermore, heat treatment is performed at a heating temperature (350℃ x soaking time 480m)
1n, closed.

(Test method) A thin steel sheet heat-treated after 2N plating of Ni plating + Ni-P alloy plating according to the present invention, and a thin steel sheet heat-treated with Ni plating as it is or with only Ni plating as a comparative example were tested in the following method. The test was conducted.

(1) Hardness measurement The plating surface hardness is Hv (5g), and the steel base hardness of the steel plates obtained in Examples and Comparative Examples is I-1v (500
g) Two types of hardness measurements were performed.

(2) Scratch resistance In order to check the scratch resistance of the plating surface layer, a weighted scratch strength tester (HE I DON-143/D manufactured by Himoban Kagaku Co., Ltd.) was used.
), the sample was scratched with a sapphire needle under a constant load. At that time, the state of defects on the sample surface was observed. The evaluation was expressed as the load at which flaws began to be observed.

(3) Regarding the salt spray corrosion resistant flat plate part and the 6mm Erichene overhang processed part,
The occurrence of red rust after 4 hours of the salt spray test (J 15Z2371) was evaluated. The flat plate portion was evaluated using a 10-point evaluation method [10 points (good) → 1 point (bad)], and the Erichene overhang 6 mm processed portion was evaluated as ◎ Good, O Slightly Good, Δ Slightly Poor, and X Poor.

The plating conditions, heating conditions, and test results of the above Examples and Comparative Examples are summarized in Table 1. The thickness of the Ni--Fe alloy layer was measured by glow discharge emission spectrometry.

From Table 1, the following is clear.

■ The surface hardness of the comparative example is AsP 1 a without heat treatment.
The Hv (5g) in t ed is 285, but when heat treated, it softens to 155-180.

In the second example, Hv was 305 to 710, indicating that the plating surface layer was significantly hardened.

Comparative examples heat-treated with a weighted scratch strength tester using the Uwaido Kodan weighted scratch strength tester were scratched by an Ig load, whereas in the examples of the present invention, all scratches were 3g or more, and the plating surface layer It can be seen that the scratch resistance improves as the material hardens.

It can be seen that the examples of the present invention are superior in the salt spray corrosion resistance of the flat plate portion and Erichsen overhang processed parts compared to the comparative example with the same level of Ni plating coverage.

This is thought to be due to the Ni-P alloy plating layer being formed on the Ni plating layer, which has the effect of filling the plating bores of the Ni plating layer and improving the corrosion resistance by the Ni-P alloy plating layer itself.

Claims (4)

[Claims] (1) It has a Ni plating layer and/or a Ni-Fe alloy layer with an adhesion amount of 5 to 45 g/m^2 on both the front and back sides, and a P content of 3 to 15% by weight on the upper layer of at least one side, and a Ni adhesion amount of A scratch-resistant Ni-plated steel sheet characterized by having a Ni-P alloy layer of 1 to 18 g/m^2. (2) The Ni-plated steel sheet according to claim 1, wherein the Ni-Fe alloy layer has a thickness of 0.2 to 10 μm. (3) Adhesive amount of N on both the front and back sides of the steel plate from 5 to 45 g/m^2
I plating is applied, and the upper layer on at least one side has a P content of 3 to 15% by weight and a Ni adhesion amount of 1 to 18 g/m^2
After applying Ni-P alloy plating of (450-800)
°C×(0.2-900)min. A method for producing a scratch-resistant Ni-plated steel sheet, characterized by subjecting it to heat treatment. (4) The manufacturing method according to claim 3, wherein the Ni plating and the Ni-P alloy plating are electrolytically treated.