JPH08158030A - Conductor roll for electroplating line and its production - Google Patents

Abstract

PURPOSE: To provide a roll having a thermally sprayed film provided with a performance equal to that of the conventional remelting treated article in the state as it is thermally sprayed without remelting and its producing method in a conductor roll for electroplating line, which is formed by thermally spraying an Ni-Cr based self-flexing alloy containing metallic carbide particles or the like. CONSTITUTION: In the conductor roll for electroplating line, a mixed powder composed of WC and the Ni-Cr alloy is thermally sprayed directly on the surface of a roll barrel part or on an under coat thermally sprayed film composed of an alloy containing no metallic carbide provided on the surface of the roll barrel part to form a structure that the flatly dispersed WC particles 2 are enchased in a joint made of solidified particles 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductor roll for an electroplating line, and more particularly to the conductor roll excellent in corrosion resistance and wear resistance and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, a conductor roll used in an electroplating apparatus for zinc, tin, etc. is hard to be eroded by a plating solution and has a wear resistance in order to prolong the life of the roll. It is required to have excellent conditions.

As a conductor roll for electroplating treatment that can meet these requirements, the inventors of the present invention have previously proposed the conductor roll described in Japanese Patent Publication No. 61-21320. In this conductor roll, the surface of the body of the roll is coated with 10 to 90% by weight of metal carbide powder and the rest being Ni-Cr-based self-fluxing alloy powder by thermal spraying and remelting treatment. It is manufactured as a requirement, and the coating formed by the thermal spraying has a structure in which spherical metal carbide particles are randomly dispersed in a Ni—Cr based alloy.

The above conductor roll has good corrosion resistance because the roll surface coating is made of Ni-Cr alloy, and in addition, the metal carbide particles dispersed in the coating provide high wear resistance electrical conductivity. It was formed on the conductor roll for the plating line. This roll was more than 5 times as durable as the conventional conductor roll plated with Cr. However, it has been found that there is a problem that when used for a long time, the metal carbide particles fall off, foreign matter adheres to the pits after the fall off, and a scratch is generated on the steel plate to be plated.

In order to solve such a problem, the present inventors have further proposed a conductor roll for an electroplating line described in JP-A-5-9699. This conductor roll has 20% WC in Ni-Cr self-fluxing alloy powder.
The powder mixed in the range of up to 80% by weight is sprayed so that the WC particles are deformed into an elliptical shape and the major axis of the WC particles are arranged in parallel with the coating layer, and the powder is further heated at an appropriate heating temperature. By remelting the WC particles, a film layer is formed which is less likely to cause a problem due to WC particles falling off. As a result, the conductor roll 2 described in Japanese Patent Publication No. 61-21320 described above can be used. It has become possible to use it continuously for more than double its life.

However, since the above-mentioned roll has a high re-melting treatment temperature of about 1100 ° C. after thermal spraying,
However, there is a problem that the base metal tends to be deteriorated or deformed, and that a large cost is required for the countermeasure.

[0007]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a conductor roll for an electroplating line which is formed by spraying a Ni--Cr based self-fluxing alloy containing metal carbide particles. It is an object of the present invention to provide a sprayed coating with a performance comparable to that of a conventional remelted product in the as-sprayed state without performing remelting treatment.

[0008]

The structure of the conductor roll for electroplating of the present invention, which has been made as a result of intensive research aimed at solving the above-mentioned problems, has a structure directly on the surface of the roll body or on the roll. A base sprayed layer made of an alloy containing no metal carbide is provided on the surface of the body, and WC is formed on the base sprayed layer.
And a powder of Ni-Cr alloy is sprayed to form a structure in which flattened WC particles are interspersed in the joint where the particles are solidified.

Further, the construction of this roll manufacturing method is as follows.
Spraying a mixed powder of C and Ni-Cr alloy to spray
In the method for producing a conductor roll for an electroplating line, in which a film is formed on the surface of the body,
Using a powder of 90 μm, while feeding the powder at 10 to 20 kg / hr, the combustion pressure in the thermal spray machine is set to 1.0 to 1.5 MPa, and spraying is performed at a spraying particle velocity of 500 to 1000 m / sec. Therefore, an undercoat sprayed layer made of an alloy containing no metal carbide may be previously provided on the surface of the roll body, and the above method may be applied on the undercoat sprayed layer.

That is, the inventors of the present invention have found that WC and Ni-
When the mixed powder of Cr alloy is sprayed, the degree of melting of the sprayed particles is set to a level at which fluidity containing a very small amount of the molten phase is about to be lost just before solidification, and the sprayed particles collide with the target surface at high speed. Then, based on the idea that the above particles are firmly bonded to each other and integrated, and a dense film strongly bonded to the base material is obtained, a conductor roll for an electroplating line is formed.
The present invention has been achieved by knowing that the desired durability can be obtained by limiting the particle size of the sprayed material and the spraying conditions as described above.

Therefore, the thermal spray material used in the present invention may be composed of 20 to 80% by weight of the conventionally known WC and the balance Ni--Cr alloy. By selecting the WC content according to the use conditions with the above range as a guide and achieving a balance between corrosion resistance and wear resistance, overall excellent durability can be obtained.

The particle size of the thermal spray material is set to 40 μm or less because small particles melt quickly and it is difficult to obtain the melting degree required for the present invention. On the other hand, if the particle size is 90 μm or more, alloy particles that are projected in an unmelted state are generated, and further, the WC particles have the above-mentioned problem of shedding during use, so the range is 40 to 90 μm.

In the present invention, the thermal spraying material is sprayed at a normal frame temperature of 2500 to 3500 ° C., and the thermal spraying conditions at this time are the same as those for feeding the material in order to obtain the melting degree. It is necessary to make the amount (feed rate) larger than that for normal thermal spraying, and to prevent the thermal spray material from staying in the frame for too long. On the other hand, if the feed amount is too large or the residence time is extremely short, it will not melt at all. Therefore, the supply rate should be 10%, which is larger than 2-10 kg / hr, which has been conventionally regarded as suitable.
The particle velocity related to the residence time was set to 500 to 1000 m / sec, compared to the conventional 200 to 1000 m / sec. In order to spray a large amount of sprayed material with a large particle size at a high speed, it is 1.0, which is much higher than the conventional 0.2 to 0.6 MPa.
A large combustion pressure of ~ 1.5MPa is required.

The particle velocity of 500 to 1000 m / sec is such that particles having a property close to that of a solid, the melting degree of which is adjusted as described above, collide with the roll surface at a high speed so that the particles are mixed with each other or the base material. It has been confirmed that it is also suitable as a speed condition for coupling and integration between the two.

In order to specify the above conditions, a test peak
Table 1 shows the result of the flame spraying experiment conducted using the flame. As seen in Table 1, by giving a particle velocity of 500 to 1000 m / sec to the thermal spray material fed at 10 to 20 kg / hr, favorable coating properties can be obtained, and a large amount of projected particles can be well fixed. It was also excellent in terms of thermal spraying efficiency.
It was also found that the combustion pressure suitable for imparting the above particle velocity to the thermal spray material fed as described above is in the range of 1.0 to 1.5 MPa.

[0016]

[Table 1]

Also in the present invention configured as described above,
When the amount of WC in the thermal spray material is large, the bonding force with the base material tends to be low. In such a case, it is possible to obtain a favorable result by performing underlayer spraying with an alloy powder containing no metal carbide such as WC. A film is obtained. It is desirable that the thermal spraying of the base layer also be performed under the above-mentioned thermal spraying conditions regarding the material containing WC.

[0018]

In the conventional thermal spraying method disclosed in Japanese Patent Laid-Open No. 5-9699, as shown in FIGS. 3 and 4, the coating layer 4 formed by thermal spraying on the body 1 of the roll is melted. The flattened particles 2, 3 (metal carbide particles 2 and Ni-
It has a structure in which Cr-based alloy 3) is laminated. That is,
The molten phase remained considerably during film formation and was flattened because it had sufficient fluidity. Therefore, since the reaction force during lamination was small, the flattened grains 2 and 3 were completely integrated. However, microscopically, there are gaps between the grains. Further, tensile stress due to solidification shrinkage of the above-mentioned molten phase remains in the coating film, and both the adhesive force and the interparticle bonding force are weak, and it cannot be used as it is as it is by thermal spraying.

Therefore, in the above conventional method, the film is melted and solidified by subjecting this film to remelting treatment.
The densified film as shown in FIGS. 5 and 6 is obtained. However, this remelting process has a processing temperature of 1100.
As described above, the deterioration of the base material and the dimensional change become a problem due to the high temperature of around ℃, and the cost is high due to this measure.

On the other hand, in the present invention, 2500-
By controlling the particle size of the thermal spray material powder and the feed amount of the powder under the normal frame temperature of 3500 ° C. as described above, the melting degree of the thermal spray particles is controlled so that the molten phase on the verge of solidification has a very high temperature. It contains only a small amount, and the fluidity is about to be lost.Furthermore, the spray particles are collided with the roll body at the high speed so that they are mutually compressed during the collision or between the particle base materials. A matching force is generated, and even though it is an extremely small amount, it occurs in the coexistence of molten metal that plays the role of a binder, so that a solidified state similar to pressure sintering and a strong bond with the base material occur. Is done.

The film thus obtained is shown in FIGS.
As shown in Fig. 3, the Ni-Cr alloy 3 forms a dense joint in which the grains are integrated, and the WC particles 2 dispersed in a flat shape by the strong compressive force at the time of the collision are formed in the joint. The tissue is scattered and arranged parallel to the surface. Moreover, the solidification that occurs in the film is that the molten metal, which contains only an extremely small amount, finally solidifies, and no significant shrinkage occurs. On the other hand, the solidification occurs under the action of the strong mutual compressive force described above. Due to the large heat capacity of the base material, the solidification of the extremely small amount of molten phase is completed almost instantaneously due to the contact with the material, so that the compressive force is frozen and compressive stress similar to shot-peening remains. .

That is, in the present invention, the regulation of the particle size of the thermal spray material powder, the feed amount (feed rate) of the thermal spray material, the velocity of the thermal spray particle, and the combustion pressure for realizing these are combined. The above effects can be obtained. For example, when the feed amount is less than the lower limit of the present invention, the particles are melted too much, the coating film cannot be obtained, and the particles are scattered at the time of collision. The problem of will occur.

[0023]

EXAMPLES Examples of the present invention are shown in Table 2 below. This example is for confirming the effects of the present invention, and the present invention is not limited to this example. Here, the present invention is applied to a conductor roll of a halogen method electroplating line, and the roll of the present invention and a conventional roll in which a film is formed on a roll of the same specification by a conventional technique.
Compared with Le. 1 is a cross-sectional view of an example of a thermal spray coating (as sprayed) formed by the method of the present invention, FIG. 2 is a partially enlarged view of the coating of FIG. 1, and FIG. 3 is a conventionally proposed thermal spray coating (as sprayed). ) Example, FIG. 4 is a partially enlarged view of the coating of FIG. 3, FIG. 5 is a sectional view of a conventionally proposed thermal spray coating after remelting treatment, and FIG. 6 is a partially enlarged view of the coating of FIG. In the figure, 1 is the body of the roll, 2 is metal carbide particles (WC particles), 3 is a Ni-Cr alloy, and 4 is a film.

As is clear from Table 2, the roll of the present invention is formed by applying the thermal spray coating with the particle size of the thermal spray material powder, the powder feed amount, the combustion pressure and the particle velocity being respectively higher or higher than those in the prior art. Although it is the same thermal spray material, it shows the same durability as the conventional product that has been subjected to remelting treatment, even though it has not been remelted, and the cost reduction effect is remarkable by omitting remelting treatment. Is.

The durability of the roll of the present invention obtained by the as-sprayed coating is obtained because the WC particles are dispersed flatly in the dense and dense alloy joint shown in FIG. It is considered that this is due to the existing film morphology and the compressive stress remaining in the film.

[0026]

[Table 2]

[0027]

The present invention is as described above, and has the same corrosion resistance as the roll subjected to the remelting treatment after the conventional thermal spraying,
Conductor roll for electroplating line with excellent wear resistance
Since it can be obtained as it is by thermal spraying without performing remelting treatment, it becomes possible to manufacture at low cost.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an example of a sprayed coating (as sprayed) formed by the method of the present invention.

2 is a partially enlarged view of the film of FIG.

FIG. 3 Conventionally proposed thermal spray coating (as sprayed)
Sectional drawing of an example.

FIG. 4 is a partially enlarged view of the film of FIG.

FIG. 5 is a cross-sectional view of a conventionally proposed thermal spray coating after remelting treatment.

6 is a partially enlarged view of the film of FIG.

[Explanation of symbols]

 1 Roll Body 2 Metal Carbide Particles (WC Particles) 3 Ni-Cr Alloy 4 Coating

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[Procedure amendment]

[Submission date] December 27, 1994

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 7

[Correction method] Delete

Claims (3)

[Claims] 1. A base thermal spraying layer made of an alloy containing no metal carbide is provided directly on the surface of the roll body, or WC and Ni-Cr are provided on the base thermal spraying layer. A conductor roll for an electroplating line, which comprises spraying a mixed powder of a system alloy to form a structure in which WC particles dispersed in a flat shape are interspersed in a joint where the particles are solidified. 2. A method of manufacturing a conductor roll for an electroplating line, which comprises spraying a mixed powder of WC and a Ni—Cr alloy to form a film on the surface of a roll body, wherein the powder has a particle size of 40 to 90 μm. Powder of 10 to 20 k
In addition to feeding at g / hr, the combustion pressure in the thermal spray machine is 1.0 to 1.5.
A method for producing a conductor roll for an electroplating line, characterized in that thermal spraying is performed at a spray particle velocity of 500 to 1000 m / sec as MPa. 3. A base sprayed layer is formed by spraying an alloy powder containing no metal carbide on the surface of the body of the roll, and the method of claim 2 is applied to the base sprayed layer. A method of manufacturing a conductor roll for an electroplating line.