JP4234038B2 - Anticorrosive chain - Google Patents

Description

  The present invention relates to an anticorrosive power transmission chain and a conveyance chain that can be used in a corrosive atmosphere such as salt water, acid, and alkali.

Conventionally, in order to prevent corrosion of the transmission chain and transport chain, the surface of the iron base material of the chain parts before chain formation is subjected to electroplating such as zinc coating or nickel coating, or the surface of the iron base material of the chain parts is non-hydrogenated. It is known that a zinc coating is formed under an 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, patents) Reference 1).
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 that has been baked and painted at the pin press-fit area, clamping area, and bushing fitting area during peeling is easy to peel off, requiring a repair process to baked paint again, increasing costs and manufacturing time. 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.

  Accordingly, an object of the present invention is to avoid a decrease in strength due to hydrogen embrittlement, and there is no film peeling at the pin press-fitting portion or the bush fitting portion at the time of chain assembling / knitting, chain disconnection, chain use, etc. Another object of the present invention is to provide an anticorrosive chain capable of exhibiting a high anticorrosive effect over a long period even in a corrosive atmosphere such as acid or alkali.

  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 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 bush In the anticorrosion chain that is assembled and knitted at least with a connecting pin that is press-fitted between the outer plates, a zinc-aluminum alloy film is formed on one of the outer plate and the connecting pin before the chain knitting and the other is nickel-based A coating is formed before chain knitting, a zinc-aluminum alloy coating is formed on one of the inner plate and the bush before chain knitting, and a nickel-based coating is formed on the other before chain knitting, and the zinc-aluminum alloy is formed. The coating is made of zinc-aluminum alloy, zinc-aluminum-magnesium alloy, zinc-aluminum-mag Nickel, nickel-phosphorus alloy, nickel-boron alloy, nickel-phosphorus-boron alloy, nickel-, wherein the nickel-based film is formed by electroplating or electroless plating The problem is solved by being one of phosphorus-PTFE composite alloys.

  The anticorrosion chain of 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 disposed on both outer sides of the inner plate, and the bushes so as to pass between the outer plates. As long as it is assembled and knitted at least with a connecting pin that is press-fitted into the roller, there is no problem even if it has a roller.

  Since the zinc-aluminum-based alloy coating in the present invention is formed by hot-dip plating of a zinc-aluminum-based alloy, there is no problem of hydrogen embrittlement caused by electroplating or the like, and the zinc-aluminum-based alloy coating is made of an iron base material. In order to improve the adhesion with the iron base material by forming an alloy layer in which zinc and iron diffuse together at the interface of the pin, the pin press-in part and the bushing fit at the time of chain assembly knitting and chain cutting Zinc-aluminum alloy coating peeling does not occur at the joint site, and coating peeling is inevitable. Even if the iron base material is exposed due to scratches at the pin clamping site, the surrounding zinc is ionized and electrochemically The so-called zinc-aluminum alloy coating sacrificial anticorrosive action prevents the occurrence of rust, so there is no need for a repairing process again, resulting in increased costs and a longer production period. It is possible to solve the conventional problems that.

  In addition, since the zinc-aluminum alloy coating has excellent adhesion to the iron base material as described above, the coating does not peel off when the chain is used, and is more resistant to corrosion than the conventional zinc coating by electroplating. Since it is excellent, high anticorrosion performance can be exhibited for a long time due to the corrosion resistance of the coating itself and the sacrificial anticorrosive action on the iron base material.

  On the other hand, the nickel-based coating in the present invention protects the corrosion of the iron base material surface by its own anti-corrosion performance, and in particular, the nickel-based coating formed by electroless plating has excellent corrosion resistance. High anticorrosion performance for the surface of the base material can be exhibited.

  Furthermore, in the present invention, in the combination of the plate and the connecting pin or bush to be press-fitted, a zinc-aluminum alloy film is formed on one side and a nickel-based film is formed on the other side, and these members are press-fitted and integrated. Even if there is a pinhole in the nickel-based film of one member (for example, a connecting pin) that has been provided with a nickel-based film, the sacrificial anticorrosive action of the zinc-aluminum alloy of the other member (for example, a plate) is nickel-based Since it extends to one member (for example, a connecting pin) to which a coating is applied, even if a nickel-based coating pinhole is present, red rust that tends to occur on the surface of the iron base material can be prevented through this pinhole.

An anticorrosion chain which is an 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 anticorrosion 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 left and right that are disposed on both outer sides of the inner plates 11, 11. A pair of outer plates 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 The unit is assembled and knitted in the longitudinal direction of the chain, and is slidably rotated between the bush 12 and the connecting pin 14 and between the bush 12 and the roller 15 with a high surface pressure when the chain is used. .

A coating of a zinc-aluminum alloy is formed on the iron base material surfaces of the inner plate 11, the outer plate 13, and the roller 15 before chain knitting, and the iron base material surfaces of the bush 12 and the connecting pin 14 described above. The nickel-based coating is formed before chain knitting.
That is, since the zinc-aluminum alloy film of this example is formed by hot-dip plating of a zinc-aluminum alloy, there is no problem of hydrogen embrittlement in the conventional chain parts, and at the interface between the iron base material and the film. Since an iron-aluminum alloy layer and an iron-zinc alloy layer which are diffused and integrated with each other are formed, the adhesion can be further improved.
In addition, the zinc-aluminum alloy coating has better corrosion resistance than the zinc coating, and the electrochemical column is more noble than zinc, so the sacrificial anticorrosive action becomes gradual and the elution rate is slow. Corrosion resistance can be maintained.

  In addition, since the inner plate 11, the outer plate 13, and the roller 15 in a present Example use the tough steel which performed the high temperature tempering of 400-500 degreeC after quenching as a base material, the high temperature tempering effect is impaired. In order to avoid this, it is preferable that the processing temperature for forming the zinc-aluminum alloy film is 450 ° C. or lower.

  As for the zinc-aluminum alloy to form a film, a zinc-aluminum alloy to which 7 wt% or less of aluminum is added is preferable in relation to the above-described processing temperature, and in particular, magnesium or silicon is added to the zinc-aluminum binary alloy. It may be added and used as a ternary or quaternary alloy. By adding such magnesium or silicon, a protective coating such as zinc hydroxide formed at the interface with the iron base material is densified, and the corrosion resistance can be further improved.

The nickel-based film in this example can be formed by electroplating, but it is preferable to form a film by electroless plating. In this electroless plating, compared to conventional electroplating, it is hard, homogeneous and dense. A coating with high corrosion resistance can be obtained, and pure nickel (reducing agent: hydrazine), nickel-phosphorous alloy (reducing agent: hypophosphite), nickel-boron alloy (borohydride compound), nickel- When a film of phosphorus-boron alloy (reducing agent: combined use of hypophosphite and borohydride compound) is formed and iron salt or cobalt salt is used together, nickel-iron-phosphorus, nickel-cobalt-phosphorus alloy film, etc. Further, if PTFE (polytetrafluoroethylene) is dispersed in the plating bath, the composite alloy coating in which PTFE is dispersed in the alloy is formed. It is obtained.
In this embodiment, any of the above-described coatings can be used, but an alloy coating containing phosphorus or boron is preferable because the coating crystal becomes fine and the surface is smoothed by containing phosphorus and boron.

  Since the bushing 12 and the connecting pin 14 in this example are carburized steel subjected to low temperature tempering at 150 to 250 ° C. after carburizing is used as an iron base material, so as not to impair this low temperature tempering effect. It is preferable to apply a nickel-based coating treatment with a low treatment temperature, and the thickness of the coating is preferably 10 to 15 μm from the relationship between corrosion resistance and clearance with the plate.

In the above embodiment, a zinc-aluminum alloy film is formed on the inner plate 11 and the outer plate 13 and a nickel-based film is formed on the bush 12 and the connecting pin 14.
Even if a nickel-based film is formed on the inner plate 11 and the outer plate 13 and a zinc-aluminum-based alloy film is formed on the bush 12 and the connecting pin 14, the same anticorrosion effect can be obtained.
Further, a nickel-based film is formed on the outer plate 13, a zinc-aluminum alloy film is formed on the connecting pin 14, a zinc-aluminum alloy film is formed on the inner plate 11, and a nickel-based film is formed on the bush 12, and vice versa. Even if a nickel-based coating is formed on the inner plate 11, a zinc-aluminum alloy coating is formed on the connecting pin 14, a zinc-aluminum alloy coating is formed on the outer plate 13, and a nickel-based coating is formed on the bush 12, An effect is obtained.

The anticorrosion effect produced by the corrosion-resistant chain of this example is as Comparative Example 1 in which galvanized and chromate films are formed on the connecting pins, bushes, rollers, and plates, and in Comparative Example 2 as zinc coating and white rust preventive baking coating. A chain spray test applying JIS 2371 was performed on each of the chains formed with the films formed, and the effects of the chain components according to this example were confirmed.
That is, in Comparative Example 1, white rust was generated in the press-fitted portion after 48 hours, red rust was generated in the entire chain after 120 hours, and in Comparative Example 2, white rust was slightly observed after 500 hours.

  On the other hand, in the corrosion-resistant chain of this example, when a zinc-aluminum alloy coating having a film thickness of about 20 μm was formed on the plate, no red rust was generated for 1000 hours, and those subjected to electroless nickel-phosphorous plating were also 1000 hours red rust. Therefore, the anticorrosive effect of the corrosion resistant chain of this example is expected to be superior to that of the conventional zinc coating and white rust preventive baked coating, which are considered to have high anticorrosion performance. The effect is enormous.

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 ... Outer plate 12 ... Bush 13 ... Inner plate 14 ... Connection pin 15 ... Roller

Claims (1)

At least assembled and knitted with 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 that penetrates the bush and press-fits between the outer plates. In the anti-corrosion chain that
A zinc-aluminum alloy film is formed on one of the outer plate and the connecting pin before chain knitting and a nickel-based film is formed on the other before chain knitting,
A zinc-aluminum alloy film is formed on one of the inner plate and the bush before chain knitting and a nickel-based film is formed on the other before chain knitting,
The zinc-aluminum alloy coating is any one of a zinc-aluminum alloy, a zinc-aluminum-magnesium alloy, and a zinc-aluminum-magnesium-silicon alloy,
The nickel-based coating is any one of nickel, nickel-phosphorus alloy, nickel-boron alloy, nickel-phosphorus-boron alloy, and nickel-phosphorus-PTFE composite alloy formed by electroplating or electroless plating. Corrosion-proof chain characterized by that.

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