JPS5827969A - Plating method on one side - Google Patents

Abstract

PURPOSE:To improve the removability of a stop-off film considerably by immersing a steel strip to be plated which is coated with a stop-off material on the nonplating surface into molten plating metal then removing the plating metallic pieces stuck on the nonplating surface with brush rolls. CONSTITUTION:A steel strip 1 which is coated with a plating stop-off agent on the non plating surface is introduced from the inside of a furnace 2 via a deflector roller 3 into a plating metal bath 4, and is drawn out into the atmosphere via a synchronizing roller 5. Brush rollers 7 provided in such a way as to press the plating metal stuck on the surface of the plating stop-off film onto a top roll 6 are revolved in the direction opposite from that of the strip 1, whereby the metallic pieces are polished away. The removed metallic pieces are collected in a dust collector 10. Then in a cooling zone 13 the strip 1 is cooled with air down to around an ordinary temp., and is conducted into a polishing device 17 with deflector rollers 14, 15, 16, where the stop-off agent is polished away with brush rolls 18; thereafter the strip is dried with a dryer 21. Since the plating metallic films stuck on the strip are beforehand removed in the above-mensioned way, the number of brushing steps for removing the stop-off film is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of applying plating to only one side of a steel strip in a hot-dip plating method.

Recently, we have improved corrosion resistance and weldability by plating only one side of steel strips for automobiles and home appliances. So-called single-sided plated steel strips are beginning to be used.

A known method for producing this single-sided plated steel strip is to coat the strip with a plating inhibitor to prevent the plating metal from adhering to one side. ``Madato'': Anti-glare agent and 1~, water glass, silicone resin.

Silica sand, alumina, and other chemical conversion coatings are known.

However, even if coated with the plating inhibitor, plating does not occur.
Due to the physical irregularities on the surface of the 15fi film, the plated metal is partially lifted at the standing portion of the plating bath, causing various problems. Because the metal adheres to the surface of the plating stopper over time, when removing the plating stopper in the subsequent process,
It is difficult to remove the blocking film, and when the steel strip passes through each roller in the process of removing the old film, the blocking film surface becomes difficult to remove.
Since the side cover is attached to a metal plate, the plated surface will be damaged and the commercial value of the single-sided plated steel strip will be significantly reduced.

FIG. 1 shows a schematic diagram of the plating prevention film removal mechanism.

(a) shows the part where the plated metal side covers the blocking film.

(b) Shows the part where the fitting metal has not adhered. When the blocking film is removed by polishing with a brush, etc., if plated metal pieces M are attached, in the first bath, due to the plated metal pieces M,
The blocking film P cannot be ground. Although the plated metal piece M peels off in the second pass, the blocking film is still at its original thickness, and in order to remove it, it is necessary to further pass the plan through a third pass and a fourth pass. On the other hand, if no plating metal is attached, the blocking film can be completely removed in the second pass after the first pass. Therefore, if even one part of the plated metal adheres to I=J, in this example, four stages are required as the number of brushing stages, and the part where the plated metal is not coated (
In fact, it occupies most of the area).

The iron base is ground, resulting in a decrease in yield.

SUMMARY OF THE INVENTION An object of the present invention is to overcome the deficiencies of the prior art described above and to provide a reliable and inexpensive method for producing a single-sided plated steel strip.

The present invention is characterized in that a rotating brush removes the sticking metal adhering to the sticking prevention film coated on the non-plated surface of the steel strip.

The present invention will be explained below with reference to the drawings.

Figure 2 is a layout diagram showing an embodiment to which the present invention is applied;
The figure is an explanatory diagram of an example of the top roll in FIG. 2.

The steel strip 1 whose non-plated surface is coated with a plating inhibitor is cleaned by 6q in a furnace 2, guided to a plating metal bath 4 by a teflector 3, and then drawn out into the atmosphere via a non-crawler 5. At this time, due to the physical irregularities on the surface of the plated barrier film, the plated metal gets caught on the surface and is lifted up, but is removed by the brush T1-rough provided to press it against the top roll 6. The roller 7 is rotating in the opposite direction to the steel strip 1, and the plated metal pieces M adhering to the plating prevention film P are ground away in the chamber 8 and flow into the dust collector 10 through the duct 9. Here, the plated metal piece M and a part of the membrane P are collected, and the dedusted gas is discharged to the outside via the exhaust fmll by the exhaust fan 11. Next, the steel strip 1 is passed through the cooling zone 13. It is air-cooled to near room temperature and enters the polishing device 17 via the teflector rollers 14, 15, 16.

The polishing device 17 is provided with a brush roll 18 and a bank up roller 19 that faces the steel strip 1 with the steel strip 1 in between. Here, the plating barrier 11-film P is ground and removed by a plan roll 18 (not shown) while being supplied with cooling water. The ribs are squeezed by a ringer roll 20, dried by a dryer 21, and led to the next step.

Since each device is arranged as described above, the blocking film P can be easily removed by polishing in the polishing device 17.

As the brush roll 7 for polishing and removing the plated metal pieces M, it is most desirable to use metal such as steel wire, stainless steel wire, or brass wire in terms of heat resistance and removability of the plated metal pieces. It is also possible to use rolls made of aluminum.

FIG. 4 shows the number of brush steps necessary to remove the plating prevention film, which was experimentally determined by the present inventors. The solid line shows the case where the plating metal pieces adhering to the plating prevention film were removed in advance with a brush roll made of stainless steel wire, and the broken line shows the case where no such pretreatment was performed. . As is clear from this result, by removing the stuck metal pieces in advance, the number of brush steps required to remove the blocking film can be significantly reduced. When the adhering metal pieces are not removed in advance, as shown by the broken line, the removability of the blocking film is significantly impaired as the plating speed increases. This is because the number of plated metal pieces that get caught on uneven surfaces increases significantly. On the other hand, in the case of the solid line in which the adhered metal pieces are removed in advance, the number of brush stages can be considered to be approximately proportional to the plating speed.

As described above, according to the present invention, it is possible to significantly improve the removability of the blocking film, and therefore it is possible to significantly reduce the consumption cost of brushes.

It also has great industrial value because it can prevent excessive grinding, which improves product yield, and prevents the plating surface from being scratched by each roller up to the step of removing the blocking film. It is.

Note that the present invention is not limited to the above-described embodiments, and can be applied to any plating method. In addition, zinc, aluminum, lead, tin, etc. can be used as the plating metal.

[Brief explanation of drawings]

Figures 1 (a) and (1)) show the imitation mechanism of the plating-stopping film removal mechanism, Figure 2 is a layout diagram showing an embodiment to which the present invention is applied, and Figure 3 is the top of the m2 diagram. FIG. 4D is a schematic diagram showing the vicinity of the roll and a diagram showing the experimental results of the present inventors. M... Plated metal piece, P... Blocking film, 7... Blasoro box / Figure θ/V included / A's 2/, 6 Sufu 1 409- He3 Ha#th 4/l'X - 7 de θ71-7 Otsu, 71

Claims (1)

[Claims] 1. In the method of applying a coating to prevent plating on the non-plated surface of the steel strip to be plated, and then attaching hot-dip metal by dipping, the non-plated surface is coated before the non-plated surface contacts the subsequent roll. A single-sided plating method characterized by pressing a brush roll against a non-plated surface in order to remove any metal particles stuck to the surface.