JPH0381667A - Liquid and instrument for deciding surface-treated steel plate - Google Patents

Abstract

PURPOSE:To accurately decide the surface-treated steel plate in a short time by impregnating a liquid holding core, loaded in a pen type container with a cap, with a mixture of a copper sulfate solution and nitric acid or a copper nitrate solution and connecting the tip of a felt-made pen to the liquid holding core. CONSTITUTION:The decision liquid for the surface-treated steel plate is prepared by mixing the nitric acid or copper nitrate solution with the copper sulfate solution. The decision device 1 for the surface-treated steel plate is constituted by impregnating the liquid holding core 3 loaded in the pen type container with the cap with the decision liquid for the surface-treated steel late and coupling the tip 5 of the felt-made pen with the liquid holding core 3. Thus, the surface-treated steel plate and an untreated steel plate accurately are decided in a short time.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a determination liquid for determining whether or not a steel plate used for an automobile body, etc. has been surface-treated, and a determination instrument filled with this determination liquid. In particular, the present invention relates to a determination liquid and a determination device for determining zinc-based surface-treated steel sheets subjected to zinc plating, zinc alloy plating, etc.

[Conventional technology] In the past, unplated steel plates were generally used for tuning plates for automobile bodies, but in recent years, surfaces coated with zinc plating or zinc alloy plating have been used to improve the rust prevention effect. Treated steel sheets are being used. This type of surface-treated steel sheet is, for example, as shown in Figure 2, after applying zinc-iron alloy plating Z with a high zinc content to the surface of the steel sheet F, a zinc-iron alloy plating Z with a high iron content is applied.・Zinc-iron treated steel sheet with iron alloy plating Z, or zinc-nickel treated steel sheet with zinc-nickel alloy plating Z3, which has a high zinc content, on the surface of steel sheet F, as shown in Figure 3. There is a steel plate that has been treated with a certain type of treatment.

By the way, in so-called sheet metal factories that repair damaged automobile bodies, in the case of relatively light damage, a commonly used repair method is to apply putty to the damaged area and then paint it. When performing this repair method on an automobile body made of surface-treated steel sheets, putty for non-plated steel sheets (for example, polyester putty) has poor adhesion to surface-treated steel sheets, so use putty specifically designed for surface-treated steel sheets. It is necessary to take appropriate measures such as using Also, when painting, it is preferable to use a paint specifically designed for surface-treated steel sheets.

Therefore, recently, a determination device has been developed for determining whether an automobile body is a non-plated steel sheet or a galvanized steel sheet. This judgment device consists of a judgment liquid made of a color-forming liquid such as potassium ferricyanide, which has a coloring property against iron ions, and a filter paper for applying this judgment liquid to the car body.The judgment liquid is placed in a container. It is accommodated. In addition, the method of use is that the user soaks the filter paper in the determination liquid in the container, then attaches it to the metal part of the car body to be determined, and after a certain period of time, peels off the filter paper and checks whether the filter paper has changed color or not. It is decided based on. That is, the filter paper does not change color with a surface-treated steel sheet that has been subjected to galvanization, etc., but the filter paper changes color with a non-plated steel sheet, so the judgment is made based on the presence or absence of color change of the filter paper.

[Problems to be Solved by the Invention] However, in the conventional determination device described above, it is necessary to impregnate a filter paper with a determination liquid, attach it to the metal part of the automobile body to be determined, and then wait until a certain period of time has elapsed. Because it doesn't work, it takes a lot of time. In addition, this judgment requires that the paint on the surface of the metal part to be determined be scraped off with sandpaper, etc., so if the underlying steel plate is exposed on a part of the plating layer when scraping off the paint, Since the steel plate (iron ions) in the non-plated portion discolors the filter paper, the user may make a mistake in judgment. Furthermore, with the above-mentioned zinc-iron alloy plating 21 (FIG. 2) having a high iron content, there is a risk that the filter paper may change color even though it is a plating layer, leading to erroneous determination. If the damaged part is repaired using putty intended for unplated steel sheets without knowing that the car body is made of surface-treated steel sheets, problems such as blistering may occur after painting.

This invention was made in view of the above points, and aims to provide a determination liquid and a determination device that can easily and quickly determine whether a non-plated steel sheet or a surface-treated steel sheet is present, and which does not cause false determinations. .

[Means for Solving the Problems] A determination liquid for a surface-treated steel sheet of the present invention for achieving the above-mentioned object is a mixture of a copper sulfate aqueous solution and a nitric acid or a copper nitrate aqueous solution.

The copper sulfate aqueous solution as the main component is in the range of 2% by weight to saturated aqueous solution in terms of anhydrous sulfuric acid steel, and of the nitric acid or copper nitrate as an additive component, nitric acid is in the range of 0.01 to 10% by weight.
In the range of weight percent, the amount of copper nitrate is converted to anhydrous copper nitrate.
, t-to weight %.

In addition, as described in claim 2, 5 to 5 in terms of anhydrous copper sulfate.
0°05 to 3% by weight relative to 30% by weight copper sulfate aqueous solution
It is preferable to mix nitric acid or an aqueous copper nitrate solution of 0.5 to 5% by weight in terms of anhydrous nitric acid steel.

The determination instrument of the present invention according to claim 3 is the same as the above-mentioned claim 1.
Alternatively, a liquid retaining core loaded in a pen-shaped container with a cap is impregnated with the determination liquid described in 2, and a felt pen tip is connected to the liquid retaining core.

[Operation: For example, when determining whether a steel plate of an automobile body is a non-plated steel plate or a zinc alloy plated steel plate, after scraping off the paint on the surface of the metal part to be determined with sandpaper, etc.
Simply apply the determination liquid of the present invention to the metal part to be determined.
Judgment can be made instantly from the color of the gold Wj4 portion coated with the judgment liquid.

That is, in the zinc alloy plated steel sheet, the background color of silver changes to black based on the following reaction formula.

Zn+Cu5O, +1/20t-m-ZnSO4+CuO (black) On the other hand, in the case of a non-plated steel sheet, the ground color of silver changes to reddish brown based on the following reaction formula.

Fe+CuSO4-m-→ FeSO4+Cu (reddish brown) In addition, in the above reaction process between the non-determined metal and the copper sulfate aqueous solution, the copper precipitated on the zinc alloy instantly turns into copper oxide due to the strong oxidizing power of nitric acid or the copper nitrate aqueous solution. Change. In other words, if a copper sulfate aqueous solution that is not mixed with nitric acid or a copper nitrate aqueous solution is applied to a zinc alloy, the copper will precipitate without being oxidized, resulting in a so-called copper plating state and not becoming black.

According to the determination liquid according to the second aspect, the above-described effects are performed more reliably.

According to the determination device according to claim 3, after removing the cap,
If you run the pen tip in a straight line while lightly touching the metal to be determined, the determination liquid impregnated in the liquid retaining core will seep out from the pen tip, allowing the determination liquid to be applied to the metal to be determined. Easy to apply. Further, after use, by closing the cap, leakage of the determination liquid is reliably prevented.

[Example] First, examples of the determination liquid of the present invention will be described.

Example 1 Copper sulfate pentahydrate 25.0% Nitric acid 0.1% Water 74.9%X1 crushed anhydrous copper sulfate I5.0% Copper nitrate trihydrate 2.1% Water 82.9% Judgment results: Using the judgment liquids of Examples 1 and 2 above, the following metals were judged as to whether they were unplated steel sheets or surface-treated steel sheets with zinc plating or zinc alloy plating. Ta.

In addition, using the determination liquids of Examples 1 and 2 above, the results of determining whether the following automobile parts were non-plated ml or surface-treated steel sheets with zinc plating or zinc alloy plating were as follows. .

When judging automobile parts, not only do you use sandpaper to scrape off the paint on the part to be judged, but you also need to sand it off so that the surface treatment layer and the underlying non-plated steel plate form a slanted surface (feather edge). When the determination liquid is applied in a line, the surface treatment layer turns black and the unplated steel plate turns reddish-brown.
Judgments can be made accurately. Also, according to this determination liquid, the above-mentioned zinc-iron alloy Metsuki Z, which has a high content of iron, (Fig. 2)
The color also turned black, but this is thought to be due to the sufficient oxidizing power of the nitric acid or copper nitrate aqueous solution.

Next, an embodiment of the determination instrument of the present invention will be described based on the drawings.

FIG. 1 is a sectional view showing an embodiment of the determination instrument. As shown in the figure, l is a felt-tip pen type determination instrument, and this determination instrument l consists of a thin cylindrical container body 2 with both ends open.
The container body 2 is loaded with a liquid retaining core 3 made of bundled synthetic fibers, a rear stopper 4 that closes the rear end opening of the container body 2, a felt nib 5, and a cap 6. ing.

The liquid retaining core 3 is impregnated with, for example, 2.5 g of the determination liquid of the present invention described above. The pen tip 5 is fitted into the front end opening of the container body 2, with its rear end connected to the liquid retaining core 3.

The cap 6 is removably attached to the front end of the container body 2, and when the cap 6 is attached, the determination liquid contained in the liquid retaining core 3 is prevented from leaking.

By the way, although the above embodiment describes the case of determining automobile parts, the determining liquid and determining device of the present invention can be used not only for automobiles but also for determining δ of refrigerators, washing machines, and steel plates used in all kinds of applications. can.

[Effects of the Invention] As is clear from the above explanation, the surface-treated steel sheet determination liquid and determination instrument of the present invention have the following effects.

(1) Steel sheets with zinc-based surface treatment and non-plated steel sheets can be easily and instantly determined.

(2) Unlike conventional judgment instruments that judge based on discoloration of filter paper,
Since the judgment is based on the discoloration of the metal to be judged, there is no misjudgment.

(3) Since not only a copper sulfate aqueous solution but also a nitric acid or copper ferrite aqueous solution is mixed, even in the case of zinc alloy-plated steel sheets, sufficient copper oxide is generated and the color reliably changes to black, so there is no misjudgment. .

(4) Unlike conventional determining instruments, the determining instrument according to claim 3 can apply the determining liquid directly to the metal to be determined without using a filter paper, so there is no spillage of the determining liquid during the determining operation. Moreover, it is convenient to handle because it can be carried around without exposing the determination liquid by closing the cap when not in use.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of the surface-treated steel plate judging instrument of the present invention. FIGS. 2 and 3 are enlarged cross-sectional views taken through a microscope, respectively, showing a part of a typical surface-treated steel sheet. l... Judgment device, 2... Container body, 3... Liquid retaining core, 4... Stopper, 5... Felt pen nib, 6...
cap.

Claims (1)

[Claims] 1. A determination liquid for surface-treated steel sheets, characterized in that a copper sulfate aqueous solution is mixed with nitric acid or a copper nitrate aqueous solution. 2. 0.05 to 3 weight % nitric acid to a 5 to 30 weight % copper sulfate aqueous solution in terms of anhydrous copper sulfate, or a 0.5 to 5 weight % copper nitrate aqueous solution in terms of anhydrous copper nitrate. The determination liquid for a surface-treated steel sheet according to claim 1, which is a mixture of the following. 3. Judgment of the surface-treated steel plate obtained by impregnating a liquid retaining core loaded in a pen-shaped container with a cap with the determination liquid for the surface-treated steel plate according to claim 1 or 2, and connecting a felt pen tip to the liquid retaining core. utensils.