JPH11294478A - Joint for driving support roll of hot-dip aluminum plating bath - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prolong life of a joint for driving a support roll immersed in molten aluminum for use. SOLUTION: At least a part forming a main body to transmit a rotational drive force between a coupling member 7 on the drive side and a coupling member 8 on the drive side. for example, the outer cylinder 7a of the coupling member 7 on the drive side and the engaging pin 8b of the coupling member 8 on the drive side are formed of an alloy tool steel SKD61 and new canuck treatment is applied the surface thereof. A diffusion layer (p) of nitrogen formed through canuck treatment and a reinforced secondary diffusion layer (q) former through new canuck treatment are formed on the surface layer part of a parent 9 made of an alloy tool steel SKD61.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a support roll driving joint used for transmitting a rotational driving force of a drive shaft to a support roll immersed in molten aluminum in a hot-dip aluminum plating tank.

[0002]

2. Description of the Related Art When plating an object such as a steel sheet continuously through molten aluminum in a hot-dip aluminum plating tank, the steel sheet is guided by a support roll that rotates at a fixed position in the molten aluminum. I send it in the direction. Such a support roll is rotatably supported inside a hot-dip aluminum plating tank, and is connected to a drive shaft via a joint. The drive shaft rotates the support roll by transmitting the rotational drive force of a rotary drive source such as a motor installed outside the hot-dip aluminum plating tank to the support roll via a joint. 2 to 4 show specific examples of the joints to be connected.

The joint 6 shown in FIG. 1 is immersed together with the support roll 3 in the molten aluminum 2 at about 660 ° C. in the hot-dip aluminum plating tank 1, and is driven coaxially fixed to one end of the support roll 3. It comprises a member 7 and a drive-side joint member 8 fixed to the tip of the drive shaft 4. The support roll 3 and the driven-side joint member 7 are rotatably supported at fixed positions in the molten aluminum 2 by support means 5 such as bearings.

The driven-side joint member 7 is formed by forming four axial engaging slits 7b at 90 ° intervals in an opening of a circular outer cylinder member 7a as shown in FIG. The corresponding drive-side joint member 8 has a cross shaft structure,
Four engaging pins 8b protrude in the radial direction at 90 ° intervals on the outer periphery of a fixed seat member 8a fixed to the tip end. The engagement pin 8b can be inserted into and removed from the engagement slit 7b. As shown in FIG. 4, by inserting the four engagement pins 8b into the four engagement slits 7b, the two joint members 7, 8 can be inserted. Concatenation takes place. When the drive side joint member 8 is rotated by the drive shaft 4 in this state, the engagement pin 8b comes into contact with and engages with one side surface of the engagement slit 7b, and the rotational driving force of the drive shaft 4 causes the drive side joint member 8 to rotate. The support roll 3 is transmitted to the driven-side joint member 7 through the support roller 3.

[0005]

Conventionally, in the above-described joint 6, the driven-side joint member 7 and the drive-side joint member 8 are formed of carbon steel such as S55C, and the contact portion between them (the engaging slit 7b). Stellite thermal spraying has been applied to the side surface and the outer peripheral surface of the engaging pin 8b) in order to increase wear resistance. But,
The conventional structure has the following problems.

[0006] The contact portion between the two joint members 7 and 8 is rapidly melted and damaged in aluminum.

Since the melting temperature of molten aluminum is as high as about 660 ° C., the hardness of the base material of the joint members 7 and 8 is reduced.

For the above reasons, the life of a joint used in molten aluminum has been short. As a result, the aluminum plating production line is frequently stopped to replace the joints, which has led to an increase in maintenance costs and a decrease in production efficiency.

An object of the present invention is to extend the life of this type of joint, reduce maintenance costs, and improve production efficiency.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, according to the present invention, at least portions of a driven joint member and a drive joint member which mainly transmit rotational driving force are formed of alloy tool steel. The surface of the base material was subjected to a New Kanak treatment (vacuum gas nitriding treatment).

More specifically, the driven-side joint member is formed by forming a plurality of axially engaging slits in an outer cylindrical member fixed to the support roll, and the drive-side joint member is engaged with the driven-side joint member. A plurality of engaging pins to be inserted into the mating slit are provided so as to protrude, and at least an engaging slit forming portion of the driven-side joint member and an engaging pin of the drive-side joint member are formed of alloy tool steel. A structure in which a New Kanak treatment (vacuum gas nitriding treatment) is applied to the material surface can be employed.

Here, the alloy tool steel is, for example, SKD61, and the New Kanak treatment (vacuum gas nitriding treatment) is a surface treatment method as described below.

The new Kanak processing is performed after the Kanak processing, and the Kanak processing method will be described first. The Kanak treatment method is an application of the principle of diffusion of nitride atoms in a vacuum furnace. A steel base material is placed in a vacuum furnace, and NH
_In this method, the furnace is heated to about 500 ° C. by feeding ₃ and a nitriding accelerating gas, the state is maintained for 3 to 5 hours, and nitrogen is diffused into the base material to generate alloy elements and compounds. When the steel material is subjected to Kanak treatment in this manner, the surface layer of the base material has no nitrided compound or a minute nitrogen diffusion layer is formed, and the heat shock resistance (heat check property), hardness,
Physical properties such as abrasion resistance are further enhanced.

The New Kanak treatment method is a treatment method for further strengthening the diffusion layer of the base material formed by the Kanak treatment, and applying heat energy again to the diffusion layer formed by the Kanak treatment of the base material to diffuse the diffusion layer. This is a method of forming a high-density cured secondary diffusion layer on the outermost layer of the layer. When the base material of the alloy tool steel is subjected to New Kanak treatment, the thermal shock resistance and the hardness are further increased, and the rate of erosion and a decrease in hardness when immersed in molten aluminum at 660 ° C. is greatly reduced.

Therefore, at least the portions of the driven-side joint member and the drive-side joint member of the joint for driving the support roll of the hot-dip aluminum plating tank, which mainly transmit the rotational driving force, are formed of alloy tool steel, and the surfaces of the base material are formed on the base metal surfaces. By performing the New Kanak treatment (vacuum gas nitriding treatment), physical properties such as erosion resistance, heat shock resistance, hardness, and abrasion resistance to molten aluminum are further improved, and the life is extended.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a joint 6 having a structure shown in FIG. 3 will be described with reference to FIG.
Note that the same or corresponding parts as those in FIG. 3 of FIG. 1 are denoted by the same reference numerals. FIG. 1 is an exploded perspective view of a driven-side joint member 7 and a drive-side joint member 8 which constitute the joint 6. FIG.
A partially enlarged sectional view of FIG.

In this embodiment, at least a portion of the driven side joint member 7 and the drive side joint member 8 which mainly transmits the rotational driving force, for example, the outer cylinder 7a of the driven side joint member 7 and the drive side joint member 8 The engagement pin 8b is made of alloy tool steel SKD6.
1 and the surfaces thereof are subjected to a New Kanak treatment. The partially enlarged cross-sectional view of FIG. 1 shows a surface portion of the outer peripheral surface of the engaging pin 8b subjected to the New Kanak treatment, and a nitrogen diffusion layer formed by the Kanac treatment on the surface portion of the base material 9 made of the alloy tool steel SKD61. p and an enhanced secondary diffusion layer q formed by the New Kanak process.

For example, the engaging pin 8b of the alloy tool steel SKD61 is installed in a vacuum furnace, NH ₃ and a nitriding gas are sent into the furnace, and the furnace is heated to about 500 ° C. for 3 to 5 hours. When left, a diffusion layer p is formed on the surface of the engagement pin 8b. The diffusion layer p further enhances the physical properties of the engagement pin 8b, such as thermal shock resistance, hardness, and wear resistance. Further, the diffusion layer p of the engagement pin 8b is subjected to a New Kanak process for applying thermal energy to form a high-density hardened secondary diffusion layer q on the outermost surface layer of the diffusion layer p. In this case, the depth of the diffusion layer p is about 60 to 120 μm, and the depth of the reinforced secondary diffusion layer q is about 10 μm.
１２０120 μm is appropriate.

As described above, when a New Kanak treatment is applied to the engaging pin 8b made of SKD61 steel as a base material, the physical properties such as thermal shock resistance and hardness are further improved, and the erosion resistance to molten aluminum is improved. Is improved. Similarly, SKD61
When a New Kanak treatment is applied to the outer cylindrical member 7a made of steel as a base material, physical properties such as thermal shock resistance and hardness are further improved, and erosion resistance to molten aluminum is improved.

Therefore, the joint 6 of the present embodiment has a high resistance to erosion of molten aluminum, a small decrease in hardness in molten aluminum, and a long life. The joint 6 according to the present embodiment is made of SKD61 steel, and its life is improved about 10 times as compared with a joint not subjected to New Kanak treatment.

It should be noted that the New Kanak process is performed by using at least the outer peripheral surface of the engaging pin 8b and the engaging slit 7 contacting the outer peripheral surface.
It suffices to apply it to the side surface 7c of b.

[0022]

According to the present invention, at least a portion of the driven-side joint member and the drive-side joint member of the joint for driving the support roll of the hot-dip aluminum plating tank, which at least mainly transmits the rotational driving force, is formed of alloy tool steel, Since the surface of the base metal is subjected to New Kanak treatment (vacuum gas nitriding), the erosion resistance of both joint members to molten aluminum is improved, and the decrease in base metal hardness in molten aluminum is suppressed. The service life can be extended. Therefore, the maintenance cost of the aluminum plating line is reduced, and the production efficiency is improved.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view including a partially enlarged sectional view of a joint showing one embodiment of the present invention.

FIG. 2 is a side view showing a support roll of a hot-dip aluminum plating tank and a joint for driving the support roll.

FIG. 3 is an exploded perspective view of the joint of FIG. 2;

FIG. 4 is a partially enlarged view of the joint of FIG. 2;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 hot-dip aluminum plating tank 2 hot-dip aluminum 3 support roll 4 drive shaft 6 joint 7 driven joint member 7 a outer cylinder member 7 b engagement slit 8 drive-side joint member 8 b engagement pin 9 base material q secondary reinforcement diffusion treated with New Kanak layer

Claims (2)

[Claims] 1. A joint for transmitting a rotational driving force of a drive shaft to a support roll in a molten aluminum of a hot-dip aluminum plating tank, a driven joint member connected to the support roll,
A drive-side coupling member that is connected to the drive shaft and transmits rotational driving force to and from the driven-side coupling member, wherein at least a portion of the driven-side coupling member and the driving-side coupling member that mainly transmits rotational driving force is transmitted. Formed with alloy tool steel, and the surface of their base metal is treated with New Kanak (vacuum gas nitriding)
A support roll drive joint for a hot-dip aluminum plating tank characterized by applying 2. The driven side joint member is formed by forming a plurality of axially engaging slits in an outer cylindrical member fixed to the support roll, and the drive side joint member is fitted into the engaging slit of the driven side joint member. A plurality of engaging pins to be inserted are protrudingly provided, and at least an engaging slit forming portion of the driven-side joint member and an engaging pin of the driving-side joint member are formed of alloy tool steel. Kanak treatment (vacuum gas nitriding treatment)
The joint for driving a support roll of a hot-dip aluminum plating tank according to claim 1, wherein the joint is provided.