JP2006145005A - Anticorrosive chain - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an anticorrosive chain applicable with standard chain components, free of poor bending and superior in anticorrosiveness by applying thinner molten zinc plating coats thereto. <P>SOLUTION: The anticorrosive chain of standard component specifications is assembled and organized with a pair of right and left inner plates 11, 11, a bush 12 pressed between the inner plates 11, 11, a pair of right and left outer plates 13, 13 arranged on both outsides of the inner plates 11, 11, a connection pin 14 loosely passed through the bush 12 and pressed between the outer plates 13, 13, and a roller 15 loosely fitted to the outer peripheral face of the bush 12. The molten zinc plating coats each having a thickness of 10-50μm are applied to the outer plates 13 and the inner plates 11. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a corrosion-resistant chain used as a power transmission chain or a conveyance chain used in a corrosive atmosphere such as salt water, acid, or alkali.

  Conventionally, in order to improve the corrosion resistance of the transmission chain and the transport chain, the surface of the iron base material of the chain parts before chain organization has been subjected to electroplating such as zinc coating or nickel coating, or the surface of the iron base material of the chain parts It is known that a zinc coating is formed in a non-hydrogen atmosphere and a paint containing aluminum powder and silicon resin is baked on the zinc coating to form a white rust-preventing baked coating (for example, , See Patent Document 1).

Further, as a surface treatment for improving the corrosion resistance of machine elements, hot dip galvanizing treatment is defined as JISH8641.
Japanese Patent No. 3122037 (first page, FIG. 1)

However, when zinc coating is applied to chain parts, the hydrogen generated in the pickling and plating processes penetrates into the metal structure of the chain parts, causing hydrogen embrittlement in the chain parts. There was a problem of significantly lowering the mechanical strength.
Also, when nickel coating is applied to chain parts, the problem of hydrogen embrittlement is less than when zinc coating is applied, but the iron base material of chain parts is easily corroded by red rust through pinholes in nickel coating. There was a problem.

  Furthermore, when a paint containing aluminum powder and silicon resin is baked onto a zinc coating formed in a non-hydrogen atmosphere, the hydrogen embrittlement problem as described above can be solved, but the chain assembly and chain cutting are not possible. The paint baked and painted at the pin press-fitting part, clamping part, and bushing fitting part easily peels off at the time of splicing, so a repair process is required for baking the paint again, which increases costs and increases the manufacturing period. In addition, there is a problem that the coating is peeled off when the chain is used, and the coating film tends to vary in film thickness, and the corrosion resistance performance is not stable.

On the other hand, as a surface treatment for improving the corrosion resistance of machine elements, in the hot dip zinc alloy plating specified by JISH8641, the adhesion amount is specified to be 350 g / m ² or more, that is, the plating film thickness is specified to be about 50 μm or more. When such a thick plating is applied to a standard part of the chain, the bush is deformed into a barrel shape at the press-fitted portion of the inner plate and the bush at the time of assembly, and the inner diameter reduction amount becomes larger than that at the time of no treatment. As a result, the overall length of the chain is shortened, the clearance between the pin and bushing is reduced, and assembly is not possible.The deformation area of the bushing reduces the contact area between the pin and bushing, promotes chain wear elongation, The clearance between the outer plate and the inner plate is reduced by the plating thickness, and the chain is not bent. An accident occurred. For this reason, there has been no practical application of hot dip zinc alloy plating to chains with standard component specifications.

  In addition, when chain parts are manufactured in accordance with the plating thickness, since they are different from standard parts, there are problems such as an increase in cost and a long delivery time.

  Accordingly, an object of the present invention is to provide a corrosion-resistant chain that can use standard parts of the chain, has no bending failure, and has excellent corrosion resistance by reducing the film thickness of hot dip galvanizing.

  In order to achieve the above object, an invention according to claim 1 is characterized in that a pair of left and right inner plates, a bushing press-fitted between the inner plates, a pair of left and right outer plates disposed on both outer sides of the inner plate, and the bushes are free of play. In a corrosion resistant chain of standard parts specifications that is assembled and knitted at least with connecting pins that are inserted through and press-fitted between the outer plates, a hot dip galvanized coating thinned to a thickness of 10 to 50 μm is applied to the pair of left and right outer plates and the pair of left and right The above-described problems are solved by applying to the inner plate.

  Here, the reason why the upper limit of the hot dip galvanized film is 50 μm or less is that if it exceeds 50 μm, it is impossible to meet the standard part specifications as described above, and the lower limit is 10 μm or more. It is because it is technically difficult to perform plating and sufficient corrosion resistance cannot be obtained.

  Further, the invention according to claim 2 further solves the above-mentioned problem by the fact that the hot dip galvanized film is a zinc-aluminum alloy in addition to the configuration of the invention according to claim 1. Is. The zinc-aluminum alloy in the present invention includes a zinc-aluminum alloy, a zinc-aluminum-magnesium alloy, a zinc-aluminum-magnesium-silicon alloy, and a zinc-aluminum-magnesium-nickel alloy.

  The corrosion-resistant chain according to the present invention includes a pair of left and right inner plates, a bush press-fitted between the inner plates, a pair of left and right outer plates arranged on both outer sides of the inner plate, and the bushes so as to pass between the outer plates. A chain with a standard part specification that is at least assembled and knitted with a press-fitting connecting pin may be used, and even a roller may be used.

  According to the corrosion-resistant chain according to the first aspect of the present invention, since the hot dip galvanized film having a thickness of 10 to 50 μm is applied to the outer plate and the inner plate, the clearance reduction during assembly is small, Standard parts can be used, and bending defects are reduced. Further, since the hot dip galvanized film is interdiffused with the base material, ie, the outer plate and the inner plate, to form an alloy, the adhesiveness is high, and peeling during use of the chain or assembly is alleviated.

  Moreover, according to the corrosion-resistant chain which concerns on Claim 2, in addition to the effect which the corrosion-resistant chain which concerns on Claim 1 show | plays, the improvement of further corrosion resistance is show | played.

The corrosion resistant chain which is one embodiment of the present invention will be described.
FIG. 1 is an exploded view of a corrosion resistant chain according to the present invention, and FIG. 2 is a cross-sectional view of a chain unit in the corrosion resistant chain of FIG.

  First, the corrosion-resistant chain 10 of the present embodiment includes a pair of left and right inner plates 11, 11, a bush 12 that is press-fitted between the inner plates 11, 11, and a pair of left and right inner plates 11 and 11 that are disposed on both outer sides of the inner plates 11, 11. Of the outer plate 13, 13, a coupling pin 14 that is loosely inserted into the inner peripheral surface of the bush 12 and press-fitted between the outer plates 13, 13, and a roller 15 that is loosely fitted to the outer peripheral surface of the bush 12. And is knitted in the longitudinal direction of the chain.

  The inner plate 11 and the outer plate 13 described above are hot dip galvanized with a thickness of 10 to 50 μm. In order to form such a thinned hot dip galvanized film, the following method is applied.

  First, after degreasing and removing the scale, an object to be processed, that is, an outer plate and an inner plate, which are standard parts of the chain, are immersed in a molten metal bath. The metal bath used at this time is composed mainly of zinc or zinc and aluminum. Here, the main component means that the mass concentration of zinc and aluminum in the molten metal bath exceeds 50% by weight. In addition, higher corrosion resistance can be obtained by using a metal bath to which magnesium, silicon, nickel, or the like is added. At this time, it is immersed in a zinc bath to which 0.1 to 0.5% by weight of aluminum is added as the first bath. Thereafter, it is also possible to immerse in a metal bath to which magnesium, silicon, nickel or the like is added as a second bath. In this way, by adding aluminum to the first bath, it is possible to suppress the development of the iron-zinc alloy layer due to the reaction between zinc and iron as a base material.

  However, the above method alone cannot form a thinned plating with good reproducibility. Therefore, as a result of intensive studies by the present inventors, it has become possible to obtain a plating film having an optimum film thickness for each product by the following method. First, (1) by preheating the workpiece before being immersed in the molten metal bath, the growth of the alloy layer after being immersed in the molten metal bath can be suppressed and the amount of adhesion can be suppressed. (2) Next, a strong centrifugal force is applied to the workpiece taken out from the molten metal bath, and excess plating is blown off by the centrifugal force at that time. (3) Further, excessive plating is blown off by giving a powerful gas blow to the workpiece taken out from the molten metal bath. (4) Sagging is efficiently performed by performing the sagging of (1) to (3) (removal of excess plating) in a heated atmosphere. The methods (1) to (4) do not necessarily have to be performed all, and an optimum film thickness for a product can be obtained by combining these methods.

  The thickness of the plating layer is determined according to the clearance between the inner plate and the outer plate. For example, in a standard part specification chain having the identification number of 60, the clearance between the inner plate and the outer plate is 60 μm, so a plating layer with a film thickness of 15 μm corresponding to a quarter of the inner plate and the outer plate is used. Is formed.

  Moreover, since zinc-aluminum-based plating has a sacrificial anticorrosive effect, surface treatment such as electroless nickel-phosphorous plating can be employed for surface treatment applied to other components.

  As the corrosion resistant chain of this example, in which a zinc-aluminum alloy coating having a film thickness of about 15 μm is formed on the inner plate and the outer plate, red rust does not occur for 1000 hours in the salt spray test applied to JIS 2371. The corrosion resistance of the example corrosion resistance chain is expected to be about twice as good as that of the conventional anti-corrosion coating with zinc coating and white rust prevention baking coating. It is.

The assembly exploded view of the corrosion resistant chain which is this invention. Sectional drawing of the chain unit in the corrosion resistant chain of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Chain 11 ... Inner plate 12 ... Bush 13 ... Outer plate 14 ... Connecting pin 15 ... Roller

Claims (2)

A pair of left and right inner plates, a bush press-fitted between the inner plates, a pair of left and right outer plates arranged on both outer sides of the inner plate, and a connecting pin loosely inserted into the bush and press-fitted between the outer plates Corrosion resistant chain with standard parts specifications
A corrosion-resistant chain, wherein a hot dip galvanized coating thinned to a thickness of 10 to 50 μm is applied to the outer plate and the inner plate.   The corrosion-resistant chain according to claim 1, wherein the hot-dip galvanized film is a zinc-aluminum alloy.

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