JPH0244899B2 - RINKUCHEENNOTAISHOKUKINZOKUKAKUSANSHINTOSHORIHOHO - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a corrosion-resistant metal diffusion and infiltration treatment method for link chains used in lifting machines such as manual chain blocks and electric chain blocks, as well as lifting equipment or conveyors. It is.

[Prior art]

Conventionally, as a corrosion-resistant metal diffusion and penetration treatment method for link chains, as published in Japanese Patent Publication No. 51-24985, a carburized or carbonitrided layer is formed on the surface layer of the base material of a steel link chain, and then Then, nickel plating or chrome plating is applied to the surface of the carburized or carbonitrided layer to integrally form a corrosion-resistant metal layer such as nickel or chromium, and then the plated link chain is heated to partially remove the corrosion-resistant metal. A method is known in which carbon is diffused into the surface layer of a carburized or carbonitrided layer and then quenched and tempered.

[Problem that the invention seeks to solve]

However, in the case of the conventional corrosion-resistant metal diffusion infiltration treatment method for link chains, each treatment is not performed while continuously moving the link chain, so the treatment efficiency is low and heat cannot be used effectively. Therefore, there are problems in that the cost is high and a link chain having uniform mechanical strength and corrosion-resistant metal film thickness cannot be manufactured with high efficiency.

[Purpose and structure of the invention]

The purpose of this invention is to provide a corrosion-resistant metal diffusion infiltration treatment method for link chains that can advantageously solve the above-mentioned problems. A process in which a layer of a corrosion-resistant metal or corrosion-resistant alloy such as nickel or chromium having a melting point higher than the quenching temperature of the base material of the link chain is continuously integrally formed on the surface of the base material of the link chain while being transported. , the link chain is subjected to high-frequency induction heating at a temperature higher than the austenite transformation point of the base material and at the quenching temperature to diffuse and infiltrate a portion of the corrosion-resistant metal or corrosion-resistant metal alloy into the base material. The base material of the link chain is made into a tempered martensitic structure by forming a layer, immediately cooling and hardening the corrosion-resistant metal diffusion link chain, and performing high-frequency induction heating followed by cooling and tempering. A corrosion-resistant metal diffusion infiltration treatment method for a link chain is characterized in that the following treatments are carried out in succession.

〔Example〕

Next, the present invention will be explained in detail using illustrated examples.

FIG. 1 shows a state in which the present invention is carried out to perform a corrosion-resistant metal diffusion and infiltration treatment method for a link chain, and shows a degreasing tank 2 containing a degreasing liquid 1.
, a washing tank 4 containing water 3, a pickling tank 6 containing a pickling liquid 5, and a washing tank 7 containing water 3,
A plating tank 9 containing a plating solution 8 for corrosion-resistant metal made of nickel, chromium, or their alloys.
, a washing tank 22 containing water 3, and water or oil 1
A quenching tank 11 containing water or oil 12 and a tempering tank 13 containing water or oil 12 are installed in series from the rear to the front, and a link chain transfer mechanism is installed above the front and rear side plates of each tank. sprockets 14 are arranged in series from rear to front,
Furthermore, each link chain transfer sprocket 14
is rotatably attached to the frame 15 and rotated at a constant speed by a common drive device via a transmission mechanism (not shown). In addition, the quenching tank 11
High frequency induction heating coils 16 and 17 are provided between the tempering bath 13 and the link chain transfer sprocket 14 located above them.

The steel link chain 18 is wound around each link chain transfer sprocket 14 in sequence, and is wound around the adjacent link chain transfer sprocket 14.
The link chain 18 hanging down from between is immersed in the liquid in the tank, and the link chain 18 is exposed to the bottom of each tank 2, 4, 6, 7, 9, 22, and the link chain 18 is immersed in the liquid in the tank. Since the inner portions of the arcuate portions are released so as not to come into contact with each other, the inner portions of the arcuate portions of the links are also sufficiently contacted with the liquid.

The vertical portion of the link chain that enters the quenching tank 11 is inserted into the high-frequency induction heating coil 16, and the vertical portion of the link chain that enters the tempering tank 13 is inserted into the high-frequency induction heating coil 17, Sprocket for each link chain transfer 1
4, the link chain 18 is continuously transferred at a constant speed.

The link chain 18 to be processed is first sent to the degreasing tank 2 to be degreased, then sent to the washing tank 4 to be washed with water, and then sent to the pickling tank 6 to remove the link chain by pickling. Surface impurity removal and activation are performed. The pickled link chain is then sent to a washing tank 7 where it is washed with water and then sent into a plating solution 8 where it is heated to a melting point higher than the austenite transformation point and quenching temperature of the base material of the link chain. A layer of a corrosion-resistant metal such as nickel or chromium or a corrosion-resistant alloy thereof is integrally formed on the surface of the base material of the link chain by electroplating or chemical plating.
It is sent inside and washed with water.

The link chain 18 on which a layer of corrosion-resistant metal or its corrosion-resistant alloy has been formed as described above is heated by the high-frequency induction heating coil 16 to a temperature equal to or higher than the austenite transformation point of the base material and a temperature equal to or higher than the quenching temperature. It is immediately immersed in water or oil 10 in the tempering tank 11 to perform quenching, then heated to the tempering temperature by the high-frequency induction heating coil 17, and then immediately immersed in water or oil 10 in the tempering tank 13.
2 and tempering is performed, and the base material becomes a tempered martensitic structure.

Next, embodiments of the invention will be described.

Wire diameter 7.1mm, chemical composition C: 0.24%, Si: 0.17%,
Mn: 1.33%, P: 0.013%, S: 0.011%, B:
A link chain with a residual iron content of 0.0014% is passed through the equipment shown in Fig. 1, and the link chain is first degreased, washed with water, pickled, and washed with water, and then plated and washed with water. As shown in the figure, a corrosion-resistant metal layer 20 made of nickel with a thickness of approximately 13 μm is integrally formed on the entire surface of the base material 19 of the link chain, and then the link chain is passed through a high-frequency induction heating coil 16 to heat the link chain. As shown in FIG. 3, a part of the corrosion-resistant metal layer 20 is heated to approximately 880°C, which is a temperature higher than the austenite transformation point of the base metal and a temperature higher than the quenching temperature. The corrosion-resistant metal diffusion-penetration layer 21 is formed by diffusing into the surface layer of the base material 19, and the link chain immediately after forming the corrosion-resistant metal diffusion-penetration layer 21 is immediately immersed in water in the quenching tank 11. and harden it.
Next, the hardened link chain is
After being passed through a high-frequency induction heating coil 17 and subjected to high-frequency induction heating to a tempering temperature of about 410° C., it was immediately immersed in water in a tempering tank 13 for tempering.

As shown in FIG. 3, in the obtained link chain, a corrosion-resistant metal diffusion permeation layer 21 made of nickel and a corrosion-resistant metal layer 20 made of nickel are successively integrally formed on the surface of a base material 19 having a tempered martensitic structure. The average value of the sum of the thicknesses of the corrosion-resistant metal diffusion layer 21 and the corrosion-resistant metal layer 20 was about 15μ. The breaking load of the obtained link chain was 8.10 tons, the total elongation at break was 24.2%, and no peeling of the corrosion-resistant metal occurred until the link chain broke.

When a layer of a corrosion-resistant metal or a corrosion-resistant metal alloy is integrally formed on the surface of the base material by plating, hydrogen penetrates into the base material, but the high-frequency induction heating coil 16
The infiltrated hydrogen can be removed by heating for an appropriate period of time, for example, 3 to 120 seconds.
Plating can prevent hydrogen embrittlement from occurring.

The heating time in this case is determined in consideration of the size of the links forming the chain, the speed at which the link chain passes through the high-frequency induction heating coil 16, the setting conditions of the high-frequency induction heating coil 16, and the like.

When carrying out this invention, after forming a carburized or carbonitrided layer on the steel link chain in advance,
The corrosion-resistant metal diffusion and penetration treatment of this invention may also be applied. Further, a link chain adjusting and accumulating device comprising, for example, a plurality of link chain accumulating sprockets may be provided between the upper sprocket of the washing tank 22 and the upper sprocket of the quenching tank 11.

〔Effect of the invention〕

According to the present invention, while continuously transporting a steel link chain, a layer of a corrosion-resistant metal or corrosion-resistant alloy such as nickel or chromium having a melting point higher than the quenching temperature of the base material of the link chain is applied to the link chain. A part of the corrosion-resistant metal or corrosion-resistant metal alloy is formed by continuous integral molding on the surface of the base material, and by high-frequency induction heating of the link chain at a temperature higher than the austenite transformation point of the base material and at a quenching temperature. By diffusing and penetrating into the base material,
A process for forming a corrosion-resistant metal diffusion permeation layer, a process for immediately cooling and hardening the corrosion-resistant metal diffusion permeation link chain, and a process for tempering the base material of the link chain by performing high-frequency induction heating and then cooling and tempering. Since the treatment to create a martensitic structure is carried out in sequence, the link chain has high breaking strength, the corrosion-resistant metal or corrosion-resistant metal alloy layer does not peel off, and the mechanical properties and corrosion-resistant metal film thickness are constant. can be produced continuously with high efficiency by simple means, and link chains in which a layer of corrosion-resistant metal or corrosion-resistant metal alloy is integrally formed on the surface of the base material can be manufactured at the austenite transformation point of the base material. After heating at the above temperature and quenching temperature, it is cooled and quenched.
The formation and hardening of the corrosion-resistant metal diffusion permeation layer can be performed by heating twice, so that effects such as the ability to manufacture a corrosion-resistant link chain at low cost can be obtained by effectively utilizing heat.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional side view showing a state in which the present invention is carried out to perform corrosion-resistant metal diffusion and penetration treatment on a link chain, and Fig. 2 shows a state in which a layer of corrosion-resistant metal is formed on the surface of the base material of the link chain. A cross-sectional view showing
FIG. 3 is a cross-sectional view showing a state in which a corrosion-resistant metal is diffused into the surface layer of the base material. In the figure, 2 is a degreasing tank, 4 is a washing tank, 6 is a pickling tank, 7 is a washing tank, 9 is a plating tank, 11 is a quenching tank, 13 is a tempering tank, 14 is a link chain transfer sprocket, 16 and 17 is a high frequency induction heating coil, 18 is a link chain, 19 is a base material, 2
0 is a corrosion-resistant metal layer, 21 is a corrosion-resistant metal diffusion layer, 2
2 is a washing tank.

Claims (1)

[Claims] 1. While continuously transporting a steel link chain, a layer of a corrosion-resistant metal or corrosion-resistant alloy such as nickel or chromium having a melting point higher than the quenching temperature of the base material of the link chain is applied to the surface of the base material of the link chain. The link chain is continuously formed integrally with the base material, and the link chain is heated by high frequency induction at a temperature higher than the austenite transformation point of the base material and at a quenching temperature.
A process of forming a corrosion-resistant metal diffusion-penetration layer by diffusing a portion of the corrosion-resistant metal or corrosion-resistant metal alloy into the base material, a process of immediately cooling and hardening the corrosion-resistant metal diffusion-penetration link chain, and a process of quenching the corrosion-resistant metal diffusion-penetration link chain. A corrosion-resistant metal diffusion infiltration treatment method for a link chain, characterized in that the process of converting the base material of the link chain into a tempered martensitic structure by induction heating followed by cooling and tempering is performed in sequence.