JPS63282292A - Direct plating method for stainless steel sheet - Google Patents

Abstract

PURPOSE:To improve adhesive property of plating by electrolytic degreasing using stainless steel sheet as a negative electrode and electroplating with targeted metal after pickling. CONSTITUTION:A cold rolled stainless steel sheet is electrolytically degreased, using as a negative electrode. In this degreasing stage, charge density of the final negative electrode is preferably regulated to >=about 1C/dm<2>. Then, the stainless steel is pickled in an usual way and plated with the targeted metal. The time elapsed from the degreasing stage to the plating stage is preferably regulated to <=30sec. Zn, Ni, Cu, Co, Fe, Sn, Pb and their and alloys are usable as plating metal. By this method, the excellent adhesive property of plating is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method of directly electroplating a cold-rolled stainless steel sheet as rolled to obtain a stainless steel sheet with a modified stainless steel surface.

(Prior Art) With the expansion of uses for stainless steel sheets, the use of electroplating on stainless steel has recently increased.

However, since the surface of a stainless steel plate is passivated, it is difficult to activate the surface with a normal pickling process. For this purpose, the actual situation is to carry out Ni strike plating after normal degreasing and pickling, and then electroplating the target metal. As described above, the plating work becomes complicated, and furthermore, it becomes necessary to newly install Ni strike plating equipment in the line for plating the target metal, which causes an increase in costs.

Electrolytic degreasing methods include a method in which the stainless steel plate itself is used as a negative electrode, a method in which the stainless steel plate itself is used as a positive electrode, and an indirect energization method in which a positive electrode and a negative electrode are alternately combined. In the latter case, it is common to use a stainless steel plate as the positive electrode at the final exit of the degreasing process to avoid adhesion of floating matter in the degreasing solution.

(Means for solving the problem) Among the above methods, the present inventors have proposed a method in which the stainless steel plate is used as the negative electrode throughout, and a method in which the polarity is reversed from normal using the indirect energization method and the negative electrode is used on the final outlet side. It was discovered that when used on steel plates, the passive film is reduced.

It has also been found that stainless steel sheets softened and annealed after rolling require long electrolytic degreasing and are not practical, but cold-rolled stainless steel sheets as rolled can be easily reduced, probably because the passive film is extremely thin. It has also been found that once the reduction occurs, if plating with the target metal is started within 30 seconds, plating with good adhesion can be achieved.

[Structure of the invention]

According to the present invention, a cold-rolled stainless steel sheet as rolled is used as an original plate for electroplating, in which the stainless steel sheet is electrolytically degreased using it as a negative electrode in an electrolytic degreasing process, and then pickled in a normal process to achieve the desired A method for directly plating a stainless steel sheet is provided, the method comprising electroplating a metal.

However, in this method, floating substances in the degreasing liquid may adhere to the stainless steel plate, so it is preferable to continuously pass the degreasing liquid through the mouth.

Here, the reduction condition for the as-rolled cold-rolled stainless steel sheet must be 1 coulomb ldr& or more, and if it is less than that, the reduction will be insufficient and the plating layer will peel off.

The target metals to be plated are Zn, Ni, Cu, Co,
Fe, Sn.

Various platings such as pb and alloy plating thereof are possible.

[Description of embodiments]

The following will explain based on examples.

Examples As-rolled cold-rolled stainless steel sheets with a thickness of 0.25 mm shown in Table 1 were subjected to electrolytic degreasing under the conditions shown in Table 2, followed by ordinary pickling, and then subjected to the conditions shown in Table 3. Electroplated with. However, the time required from degreasing to plating was within 30 seconds. These samples were subjected to a close bending test, and the peeling of the plating layer at the bent portion was observed using a 20x microscope. The results are shown in Table 4. From Table 4, all the platings according to the present invention showed excellent plating adhesion.

Table 1 Table 2 Table 3 However, the plating thickness was 15 g/m per side.

Table 4

Claims (1)

[Claims] 1. A method of electroplating using an as-rolled cold-rolled stainless steel plate as a base plate, which comprises electrolytically degreasing the stainless steel plate using the stainless steel plate as a negative electrode in an electrolytic degreasing process, and then pickling in a normal process. , a method of directly plating stainless steel sheets, characterized by electroplating the desired metal. 2. The method according to claim 1, which is a method of directly plating a stainless steel plate, characterized in that when electrolytic degreasing is performed by indirect energization, the stainless steel plate becomes a negative electrode on the final exit side of the degreasing process. . 3. The method according to claim 1, wherein the stainless steel plate is electrolytically degreased at 1 coulomb/dm^2 or more at the final negative electrode part of the electrolytic degreasing process, and the target metal is electrolyzed within 30 seconds after degreasing. How plating is started.