JPH03104855A - Ni diffusion-treated steel sheet, ni-plated steel sheet, and production of ni-plated steel sheet - Google Patents

Abstract

PURPOSE:To make it possible to meet the purpose where superior corrosion resistance is required of either of internal surface and external surface by providing Ni-diffused layers to the surface and the rear surface of a steel sheet, respectively, and regulating the above Ni-diffused layers in both surfaces to specific g/m<2> expressed in terms of Ni, respectively. CONSTITUTION:Ni-diffused layers are formed in the surface and the rear surface of a steel sheet. The Ni-diffused layer in one surface is regulated to 2-10g/m<2> expressed in terms of Ni, and the Ni-diffused layer in the other surface is regulated to <2g/m<2> expressed in terms of Ni. Ni plating layers are formed on the Ni-diffused layers in the surface and the rear surface of the Ni diffusion-treated steel sheet, respectively. The surface and the rear surface of the steel sheet are plated with Ni by 2-10g/m<2> coating weight and <2g/m<2> coating weight, respectively, and then, heating is applied to the above surfaces to allow plated Ni to diffuse and penetrate into the steel and form Ni-diffused layers where the Ni plating layers are dissipated, and further, Ni plating is applied again to both surfaces. By this method, the Ni-diffused layers dissimilar in Ni diffusion quantity to each other can be easily formed on the surface and the rear surface of the steel sheet.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is applicable to most of the various home appliance parts that undergo deep drawing, such as interior cans for dry batteries, which require strict press workability, and which are suitable for use in products after press forming. In applications where excellent corrosion resistance is required on either the inner or outer surface, an optimal Ni-plated steel sheet and its manufacturing method, as well as the above-mentioned N
The present invention relates to a Ni-diffused steel sheet that is a material for i-plated steel sheets.

(Prior art) As a prior art, for example, Japanese Patent Application Laid-Open No. 61-235594 discloses that after electrolytic Ni plating is applied to a cold-rolled steel plate, the plate is heated to 600 to 800°C for 1 minute to 800°C in a neutral or reducing atmosphere. By heating and holding for 15 hours to diffuse the steel base and Ni plating layer, a Fe-Ni alloy layer with a thickness of 4 μm or less is formed at the interface between the two, and the steel base and Ni plating layer are firmly bonded. A method for producing a Ni-plated steel sheet is provided in which the adhesion of the Ni-plated layer is strengthened and the corrosion resistance is improved by eliminating bottle holes by diffusion.

(Problems to be Solved by the Invention) The present inventors investigated the press workability and corrosion resistance of the Ni-plated steel sheet obtained by the above manufacturing method, and found that the Fa-Ni alloy layer has a large thickness within 4 μm. It has been found that although corrosion resistance improves as the temperature increases, it conversely hardens the steel itself and reduces press workability (limit drawing ratio, etc.).

The Ni-plated steel sheet manufactured by the above method has almost the same thickness of F on the front and back sides, not only when the amount of electrolytic Ni plating on the front and back surfaces is the same, but also when the amount of electrolytic Ni plating on the front and back surfaces is different.
When an e-Ni alloy layer is formed and the amount of electrolytic Ni plating on the front and back surfaces is the same, a Ni plating layer of approximately the same thickness is formed on the Fe-Ni alloy layer on the front and back surfaces, and the amount of electrolytic Ni plating on the front and back surfaces is the same. When they are made different, Ni plating layers with different thicknesses are formed on the Fe--Ni alloy layers on the front and back surfaces. Therefore, the Ni-plated steel sheet obtained by the above manufacturing method is
It is the most suitable material for applications that require severe corrosion resistance on both the inner and outer surfaces, but press workability is not so strict, or applications that do not require high corrosion resistance on both the inner and outer surfaces, but require strict pressability. Pressability is strictly required for products such as cans and various semiconductor cases.
It was found that this material is not suitable for applications where the inner surface does not require much corrosion resistance, but the outer surface requires severe corrosion resistance.

The present invention provides an optimal Ni-plated steel sheet, a method for manufacturing the same, and a material for the Ni-plated steel sheet in applications where press workability is strictly required and severe corrosion resistance is required on either the inner or outer surface. The present invention provides a Ni diffusion treated steel sheet.

(Means for solving problems) The gist of the present invention is as follows.

(a) The WH board has Ni diffusion layers on the front and back surfaces, the Ni diffusion layer on one side is 2 to 10 g/m2 in terms of Ni, and the Ni diffusion layer on the other side is less than 2 g/rn' in terms of Ni. A Ni diffusion treated steel sheet characterized by the following.

(b) N characterized by having a Ni plating layer on the Ni diffusion layer on the front and back surfaces of the Ni diffusion treated steel sheet of (a) above.
i-plated steel plate.

(c) 2 to 10 g/rn of NL on the front and back sides of the steel plate, respectively.
”, after plating less than 2 g/rn!, heat the plated Ni to diffuse into the steel, form a Ni diffusion layer that eliminates the Ni plating layer, and then apply Ni plating to both sides again. Characteristic method for manufacturing Ni-plated steel sheet. (Function) The present invention will be explained in detail below along with the function.

First, the reasons for limiting the numerical values of the Ni-plated steel sheet of the present invention and the Ni-diffused steel sheet that is the raw material for this steel sheet will be described.

Figure 1 shows the influence of the amount of Ni diffusion on the corrosion resistance (SST) of Ni-plated steel sheets. Figure 1 shows the results of investigating corrosion resistance (SST) by fixing the metal Ni in the upper layer of the Ni diffusion layer at 20 g/m' and varying the amount of Ni diffusion in the Ni diffusion layer. It can be seen that almost constant high corrosion resistance can be obtained in the above manner. Moreover, if it exceeds 10 g/rn', the effect will be saturated and the cost will increase.

FIG. 2 shows the influence of the Ni diffusion amount on the press workability of Ni-plated steel sheets (limit drawing ratio during deep drawing when using an aluminum-killed cold-rolled steel sheet with a thickness of 0.25 mm). Figure 2 shows the amount of Ni diffused and the amount of Ni plating on the die side (outer side of the product), respectively, 4 g/m2,
20g/m", and the total Ni plating amount of the Ni diffusion amount and Ni plating amount on the punch surface side (inner surface side of the product) is 15 g/rn.
' is fixed and the amount of Ni diffused on the punch surface side is changed to investigate the pressability.
It can be seen that when the pressure exceeds this value, the pressability deteriorates rapidly.

From the above, in the Ni-plated steel sheet of the present invention and the Ni-diffusion-treated steel sheet that is the raw material for the Ni-plated steel sheet, the Ni diffusion layer is
Converted to 2 to 10 g/m' on one side of the steel plate and 2 g/m' on the other side.
It is limited to less than

Ni (
The amount of metal Ni) plating is appropriately selected depending on the application, but is generally 5 to 30 g/rn' per one side,
Depending on the application, the amount of plating on the front and back of the steel plate may differ,
The amount of plating can be the same.

In the Ni-plated steel sheet of the present invention, whether the surface with a large amount of Ni diffusion should be the outer surface or the inner surface of the product after press working can be selected as appropriate depending on its use and purpose.

Generally, a higher degree of corrosion resistance is often required on the outer surface of the product after press working, and processing is often performed so that the surface with a large amount of Ni diffusion becomes the outer surface of the product.

Next, a method for manufacturing a Ni-plated steel sheet according to the present invention will be explained.

In the method of the present invention, 2 to 10 g/m2 is applied to the front and back surfaces of the steel plate, respectively.
After applying Ni plating of less than 2 g/rn'', the plated Ni is heated and diffused into the steel to form a Ni diffusion layer in which the Ni plating layer disappears, and then Ni plating is performed again.

The shape or thickness of the Ni diffusion layer that has eliminated the Ni plating layer
By employing heat treatment conditions in which Ni in the plating layer substantially diffuses into the steel, Ni in the thin Ni plating layer substantially diffuses into the steel. Moreover, when an unannealed steel plate is used as the steel plate, annealing and the above-mentioned heating diffusion treatment can be performed simultaneously.

Ni plating process to obtain the Ni diffusion layer in this way,
By separating the Ni plating process to obtain the Ni plating layer on the Ni diffusion layer, it is possible to extremely easily form Ni diffusion layers with different Ni diffusion amounts on the front and back sides of the steel sheet, and also to separate the Ni diffusion layer and the Ni plating layer. Since Ni is formed separately, Ni
The plating layer can be selected from bright Ni plating, black Ni plating, etc. depending on the application, and the range of applications will be expanded.

(Example) Next, an example of the present invention will be described. Examples below. In the comparative example and the conventional example, an unannealed aluminum killed cold-rolled steel plate having a thickness of OJOmm was used as the steel plate.

In addition, the heating diffusion treatment was carried out in a 3% H2 atmosphere and the remaining N2 atmosphere at 620°C.
The box annealing method was performed by heating at ℃ for 8 hours. Further heating (annealing)
The subsequent rolling reduction ratio was set to 0.8%.

[Example, comparative example]

In the process shown in FIG.
An i-plated steel plate was manufactured.

The amount of Ni plating on the front and back surfaces of the steel sheet before and after heating, and the amount of Ni diffusion on the front and back surfaces of the product steel sheet. The Nii amount is shown in Table 1. The amount of Ni plating before heating corresponds to the amount of Ni diffusion in the product steel sheet.
The amount of Ni plating after heating corresponds to the amount of Ni layer in the product steel sheet.

[Conventional example]

A Ni-plated steel sheet was manufactured using the conventional process shown in FIG. 4, in which the front and back surfaces of the steel sheet were plated with Ni and then heated, and only a portion of the Ni plating layer on the front and back surfaces was diffused into the steel.

Table 1 shows the Ni plating amount on the front and back surfaces of the steel sheet before heating, the Ni diffusion amount, and the Ni layer amount on the front and back surfaces of the product steel sheet.

As shown in Table 1, the amount of Ni diffused on the front and back surfaces of the product steel sheet is almost the same.

Using the above-described Ni-plated steel sheets of the present invention, comparative example, and conventional example, the following (a). Corrosion resistance and workability were evaluated using the method (b).

(a) After processing the steel plate into a cylindrical shape with a drawing ratio of 1.95 and an inner diameter of 10 mm by deep drawing for corrosion resistance, the JIS
Z-23711. :Continuous SST was performed for 1ohr. The evaluation was based on the incidence of red rust (%).

(b) Workability Continuously perform 1000 presses similar to section (a),
Evaluation was made based on the ratio of cylinders in which cracks occurred.

The above evaluation results are shown in Table 1.

(Effects of the Invention) As described above, the Ni-plated steel sheet of the present invention has extremely excellent press workability and single-sided corrosion resistance, and is used for applications such as interior cans for dry batteries, which require strict press workability, It is extremely useful in applications that require excellent corrosion resistance.

Further, according to the manufacturing method of the present invention, different N on the front and back surfaces of the steel sheet
A Ni diffusion layer with a diffusion amount of i can be formed extremely easily,
The above Ni-plated steel plate can be easily manufactured.

Furthermore, the Ni-diffusion-treated steel sheet that is the material for the Ni-plated steel sheet of the present invention is obtained by purchasing a steel sheet from a steel manufacturer and applying N to this steel sheet.
By applying Ni plating at a plating company that applies i-plating and supplies Ni-plated steel sheets to can manufacturers, it is possible to manufacture excellent Ni-plated steel sheets as described above and supply them to can manufacturers. It has a rich and excellent effect.

[Brief explanation of drawings]

Figure 1 shows the effect of N on the corrosion resistance (SST) of Ni-plated steel sheets.
Fig. 2 is an explanatory diagram showing the influence of the amount of Ni diffusion on the press workability of Ni-plated steel sheets, Fig. 3 is a process diagram of the example and comparative example, and Fig. 4 is an explanatory diagram showing the influence of the amount of i diffusion. is a process diagram of a conventional example.

Claims (3)

[Claims] (1) Having Ni diffusion layers on the front and back surfaces of the steel plate, and N on one side.
A Ni diffusion-treated steel sheet, characterized in that the i-diffusion layer has a Ni diffusion layer of 2 to 10 g/m^2 in terms of Ni, and the Ni diffusion layer on the other side has a density of less than 2 g/m^2 in terms of Ni. (2) Ni on the front and back surfaces of the Ni diffusion treated steel sheet of claim (1)
A Ni-plated steel sheet comprising a Ni-plated layer on a diffusion layer. (3) Add 2 to 10 g/m of Ni on the front and back surfaces of the steel plate.
After applying plating less than 2.2g/m^2, heat the plated Ni to diffuse and penetrate into the steel to form a Ni diffusion layer where the Ni plating layer disappears, and then apply Ni plating to both sides again. A method for manufacturing a Ni-plated steel sheet, characterized by the following.