JPS58221290A - Method for protecting iron surface of steel sheet electroplated on one side - Google Patents

Abstract

PURPOSE:To protect surely the non-plated surface of a steel strip, by applying plating of the amt. at which the plating dissolves nearly thoroughly at the time when the strip emerges from the final plating cell on the other surface of the steel strip during plating on one surface of the strip. CONSTITUTION:Plating of the amt. at which the plating dissolves nearly thoroughly at the time when a steel strip emerges from the final plating cell is applied to the other surface of the strip during plating on one surface of the strip in the stage of producing the sheet electroplated on one side. In the case of, for example, plating one side with an iron-zinc alloy, plating is applied at high current density on the plating surface by supplying the current thereto through the electrodes which face said surface. On the othe hand, electricity is conducted at low current density to the non-plating surface through the electrode on the side facing the same and the plating of a high zinc content is stuck thereto by using the same plating soln. Since this plating layer has a high zinc content, it has good solubility and at the time when the strip is taken out of the plating cell finally, no smut remains thereon and is dissolved thoroughly.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for protecting the steel surface of a single-sided electric knife + steel plate.

Normally, one side of the steel strip is opposite to one side of the copper strip.
, Apply a current between the pole and the copper strip, apply heat, and apply a leakage box to the other side of the steel strip.

If metal goes around and adheres to the metal, it will deteriorate the performance of the product and damage its commercial value. Therefore, edge masks, etc. are placed at both ends of the copper strip to avoid the current from going around. .

However, since the non-metallic surface also comes into contact with the liquid, the non-metallic surface will be corroded in the acidic wet area.

In particular, Fe+3 io υ is about 0. Corrosion is condemned when it exists above I Vt, and when Fe+3 iosi exceeds 1.0 Vt, corrosion is extremely severe, and the appearance of non-metallic copper belts can be clearly seen with the naked eye, impairing commercial value. It also has the disadvantage of deteriorating performance such as paint adhesion.

The present invention has been made to advantageously solve these drawbacks, and is characterized by the fact that when manufacturing one-sided electrical mesh + steel plate, the final mesh is applied to the other side of the steel strip while the chain strip is being drilled on one side of the soil. One side electrometallurgical method + iron surface protection method of steel plate, which is characterized by subjecting it to a method that almost dissolves when it leaves the inner tank, and when manufacturing one-sided electric slope plate, one side of the steel strip is covered with wet soil while the other side of the steel strip is applied. When leaving the final membrane tank, the vertical membrane that dissolves
A method for protecting the steel surface of a single-sided electrically heated steel plate, which is characterized in that the unmelted metal on the other side of the electrically heated steel strip is removed from the final electrically heated steel sheet. It is.

That is, in the present invention, in order to prevent etch marks and oxide film formation on the iron surface (non-method surface) due to the oxidation solution, a slight etchant is applied to the iron surface. This method ensures that the iron surface is protected by performing a 51-step process that melts the surface of the steel.

Therefore, for example, in a metal construction system consisting of a plurality of metal v + cypress, the amount of metal + metal to be dissolved between the electrodes of each metal tank is transferred to the other side (iron side) of the copper strip at each electrode position. Others, such as adding sufficient meth+ in the first meth tank and not applying meth+ in the second meth tank, so that it is almost dissolved when it leaves the final meth tank. This may take any appropriate form.

For example, in the case of an iron-zinc alloy single-sided mesh, apply iron-zinc alloy electricity υ 10 to the raw part of the iron-zinc alloy at high current density through an electrode opposite to it, and then apply the same When current is applied at a low current density (for example, 50&drn2 or less) through the electrode on the side opposite to the electrode, metal with an extremely high zinc content adheres.

This METSU+ layer dissolves when it moves to an area that does not oppose the current-carrying electrodes in multiple cells, but because it has a high zinc content, it has good solubility, and when it finally leaves the METSUHI cell, it dissolves.
It is possible to completely dissolve it without leaving any residue.

In addition, even if the iron surface (non-metallic surface) is partially exposed in the middle of multiple cells, zinc remains in the vicinity. In this way, it maintains the iron surface (non-sticky surface) uniformly over the gold mine of the copper strip, retains the original appearance of a shiny and clean iron surface, and has excellent chemical conversion paint adhesion. It can be iron-faced.

In this way, when it leaves the final mesh tank, it is coated with the melted metal. When leaving the tank, if the residual amount of zinc on the iron surface is about 2097 B2 or less, preferably 10 tn9/rn2 or less, it can function as an iron surface, that is, the quality of a single-sided Metsushi steel plate can be ensured. can.

Furthermore, as mentioned above, by removing the remaining metal on the iron surface by electrolytic treatment etc., it is possible to obtain a more reliable single-sided metal steel plate. /IB2 or less, there is no need for precise control, and steel surfaces can be easily protected.

The method of the present invention can be advantageously applied to any type of metal material such as vertical metal material, horizontal metal material, single layer material, multi-layer material, alloy material thereof, etc. It is something.

Furthermore, when applying the method of the present invention, it is also possible to combine it with other post-processing techniques for improving the chemical conversion treatment properties, such as the Zura Sync technique and the Flashmet+ technique.

By doing this, it is possible to reliably protect the non-metallic surface (iron side) of the single-sided electrometallic metal plate + steel plate from etching by raw lacquer, prevent quality deterioration of the single-sided electrometallic metal plate + steel plate, and increase the commercial value.

Further, excellent effects such as non-metallic surface (iron surface) snares can be easily made, and industrially precise protection can be achieved.

Next, examples of the method of the present invention will be listed together with comparative examples.

A copper strip is passed through an iron-zinc alloy solution consisting of iron and zinc sulfates, one side is coated with a metal layer, and the iron side (non-metal side) is coated with a protective layer under the conditions shown in the table below. Dissolved in METSU solution.

Metsu+liquid composition zFe+2-55f/l, Fe+3-table below, zn+2 = 50 Ml, excess H2SO4K Y
pH = 1.2 K ill, temperature 60°C.

Note 1 = Theoretical Metsu + Den is a protective Metsu 10 company that ignores Metsu + dissolution in liquid.

Note 2: In Example 4, sodium dihydrogen phosphate 200
In an aqueous solution (voice 5.60°C) consisting of carbon dioxide and sodium hydroxide 10 f/l, an electrolytic treatment was performed using the metal + steel strip as an anode and a current density of 100 A7 dm2X for 1 second. Removed the metal on the surface). The remaining Zn needles after removal are traces, and the appearance after removal is shown in the appearance column in the table.

Note 3 = Appearance of iron surface after final cell ○; Shiny and clean appearance equivalent to cold rolled steel sheet △: Slightly brownish appearance It is expressed as the degree of coverage after treatment.

○: Completely covered, △: Some scratches are observed.

Note 5. Secondary adhesion Adhesion of paint film after immersion type ricinate treatment, electrodeposition coating, intermediate coating, and top coating, and immersion in water at 40°C for 10 days.

0: No peeling at all, △: Slight peeling is seen when a cut is drawn to reach the base iron of the 2-knot pattern.

As described above, in the present invention (example), no cracking or cracking on the other surface (iron surface) was observed, and an excellent effect was obtained; however, in the comparative example, The entire surface was etched: Jji, reducing the product value.

Claims (1)

[Scope of Claims] 1. When producing a single-sided electrometallurgical steel plate, a metallurgical coating is applied to the copper strip in an amount that will almost dissolve when it leaves the final electrolytic tank on the other side of the copper strip. A method for protecting the steel surface of a single-sided electromechanical steel plate. 2. When manufacturing single-sided electromechanical steel sheets, one side of the steel strip is coated with electrolyte in an amount that is almost dissolved when the steel strip leaves the final electromechanical tank, and one side of the steel strip is dissolved in soil when leaving the final electrochemical tank. Denki Metsu〒To remove undissolved metal on the other side of the steel strip 41
A method for protecting the iron surface of a single-sided electrometallic and steel plate.