JPS63181702A - Metal binding band - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) This invention relates to a metal binding band such as a boot band.

(Prior art) When spot welding is a location where corrosion should be avoided, i.e., where the fastening function would be impaired due to peeling or cutting, for example on a boot band, corrosion should be prevented. It is known to change the material of the metal coupling band itself to a corrosion-resistant material.

For example, in the metallographic microscopic ears of the longitudinal section at the spot welding point 12 of the metallic bonding band 10 shown in FIG.
After fastening the metal coupling band 10 spot-welded to the lever 18 in a state in which the parts 6 are superimposed, an accelerated corrosion test is conducted, and the state is shown after 750 hours have elapsed. Although this product uses stainless steel (SUS430), which is the conventional JIS standard, there are large oval-shaped dark areas on the left and right sides. This item has 20 areas of corrosion due to crevice corrosion.
It is clear that corrosion has progressed significantly.

On the other hand, Fig. 2 shows the stainless steel (SUS43) shown in Fig. 4.
0) was tested under the same conditions using stainless steel to which niobium and nickel had been added in advance. The amount of corrosion was several tenths of a second, indicating that a significant effect can be expected by changing the material, but crevice corrosion has not been completely prevented.

(Problems to be Solved by the Invention) However, this method of improving material quality has the following drawbacks.

In other words, materials containing rare metals such as niobium and nickel are expensive and unsuitable for general use, and improvements in corrosion resistance generally impair spot weldability and cause peeling. For example, it becomes easier to do. For this reason, the means for preventing crevice corrosion may end up impairing its functionality, and does not lead to complete prevention of crevice corrosion.

Note that improving the quality of the material is also quite effective if the purpose is simply to prevent surface corrosion. In other words, most of the corrosion is in the ionic state,
This is because the condition is caused by corrosive substances in a solution state, and the surface tends to dry quickly. However, crevice corrosion has the following characteristics, and unless these are resolved, the problem cannot be fundamentally solved.

That is, the undercarriage area of an automobile where boot bands and the like are used is exposed to strongly corrosive chemical substances such as various acids and salts. There, solutions of these chemicals are drawn into the gap between the boot bands by capillary action.
Moreover, once it enters, it remains in the air for a long time without being removed, and as it becomes concentrated, it undergoes severe corrosion. Furthermore, such gaps and their sub-
The metal composition changes around the joints made by 7-t welding, and the parts that are least desired to be corroded are the most susceptible to corrosion. Moreover, it is practically difficult to create a special structure such as enlarging or closing the gap to prevent corrosion, or to harden it with a mold.

SUMMARY OF THE INVENTION The present invention solves these problems and provides a metal coupling band that can reliably prevent crevice corrosion and does not impair spot weldability.

(Means for Solving the Problems) In order to solve the above problems, the metal coupling band according to the present invention has the following configuration.

In other words, the surface of a metal coupling band having a gap where crevice corrosion is likely to occur, such as a spot weld where tensile force is applied during tightening, is preliminarily coated with a paint having a viscosity that can penetrate into at least the gap. shall be.

(effect) Let's talk about the action.

Since the gap 22 of the metal bonding band 10 is filled with paint in advance and coated, there is no suction or concentration of the corrosive solution due to capillary action, and the structure is such that it can be completely removed. , no crevice corrosion occurs.

(Example) Preferred examples embodying the present invention will be described below in detail with reference to the drawings.

In FIG. 5, the metal coupling band 10 is made of stainless steel W.
4 (SUS 430), with both ends of the steel strip 14 facing each other and spot welded on the outer peripheral surface of one end of the curved plate-shaped lever 18.
This boot band has a fastener 26 for fastening the other end 24 of the boot band, and the surface of the boot band is coated with paint. The easiest way to apply the paint is to immerse it in a one-component curing liquid paint made by adding a heat-resistant paint to an epoxy resin in order to form an epoxy-based paint film, and if necessary, immerse it under reduced pressure. It is also desirable to add pigments to classify the boots in about 12 colors so that the fine differences in the specifications of the boot bands can be clearly distinguished visually. When the boot band soaked in the paint is pulled up, the dripping paint is returned to the paint solution tank as it is, and then centrifuged to remove the drippings.The remaining excess paint is removed and the film thickness is reduced. The centrifugation time and acceleration force are adjusted so that the thickness is extremely thin, less than 15μ. Furthermore, in order to enable the paint to sufficiently penetrate and fill the gap and cover the gap from the outside, and to increase the hardness of the coating film, it is baked and dried in an electric furnace at about 180° C. for 20 minutes. The hardness of the coating film after baking and drying is approximately 2H according to the JIS pencil scratch test method, and the adhesion is determined using the JIS pencil scratch test method.
ISD 0202° Section 8.12 Class 1, Judgment Criteria JIS D 0202.9.11 Class 2.

The coating film may be extremely thin, so that the adverse effects of crack formation do not occur. If the coating thickness is too thick, the inner diameter of the boot band will change, so the coating thickness should be kept within a certain range where capillary action can occur. In addition, since a heat-resistant paint is added to the paint, a sufficient baking temperature can be applied, and the low viscosity paint can penetrate into the gap by capillary action, making it possible to fill the gap. In addition to completely sealing the gap from the outside, the metal surface within the gap is also protected, making it possible to prevent gap corrosion much more completely than by changing the material.

It is also possible to add ultra-fine metal powder, which is more likely to corrode than stainless steel, into the paint and apply 2N by spray painting.The metal powder can also be corroded and sacrificed to improve crevice corrosion resistance. Even in this case, the cost is lower than changing the material.

The metallographic micrograph of FIG. 3 shows the case of coating the boot band made of the conventional material of FIG. 4. Compared to unpainted products, painted products have fewer areas with crevice corrosion, and the amount of crevice corrosion has been drastically reduced.

The metallographic micrograph of FIG. 1 shows a coated boot band made from the improved material of FIG. 2, and it can be seen that there is no crevice corrosion at all.

(Effects of the Invention) As described above, the present invention provides an adhesive bonding band that can be used even when conventional metal bonding bands lose their function due to crack corrosion and peeling, which may cause a serious accident. Since it can completely cover and fill high gaps, it has the remarkable effect of completely preventing crevice corrosion at low cost. Also, the color coding of the boot band makes identification much easier.

Although the present invention has been variously explained above with reference to preferred embodiments, the present invention is not limited to these embodiments, and it goes without saying that many modifications can be made without departing from the spirit of the invention. It is.

[Brief explanation of the drawing]

1 to 4 show metal composition micrographs. Figure 5 is a side view showing the tightened state of the metal coupling band;
FIG. 6 is a diagram schematically showing the metal structure. 10...Metal coupling band, 12...Spot welding location, 14...Strip steel material,
16... End of steel strip, 18... Lever, 20... Corrosion point, 22...
Gap, 24... Other end, 26... Fastener.

Claims (1)

[Scope of Claims] 1. The surface of a metal bonding band having a gap where crevice corrosion is likely to occur, such as a spot weld where tensile force is applied during tightening, is coated with a paint having a viscosity that can penetrate into at least the gap. Made of metal binding band. 2. The metal bonding band according to claim 1, wherein the paint is a one-component thermosetting resin made by adding a heat-resistant paint to an epoxy resin.