KR20080010219A - Roller with self-soluble alloy powder and thermal spray coating layer using same - Google Patents

Abstract

According to the present invention, the magnetic soluble alloy powder is Fe, Fe alloy, Mo, Mo alloy, Cu, Cu alloy, Al, Al alloy, Zn, Zn based on 100 parts by weight (wt) based on nickel or cobalt based magnetic powder 2-25 parts by weight of the mixture of at least one selected from the alloy powders. When coating the surface of the roller using this self-soluble alloy powder can increase the friction and hardness of the roller surface.

Description

Self-fluxing alloy powders and roll having spraying coating layer}

1 is a partial ablation perspective view schematically showing a roller according to the present invention,

2 is a cross-sectional view showing a spray coating film according to the present invention;

3 and 4 are photographs taken in cross section of the thermal spray coating film according to the present invention.

The present invention relates to a roller having a thermal spray coating film capable of increasing the frictional force and hardness of the surface by spraying a magnetic alloy powder and a magnetic alloy powder for forming a thermal spray coating film.

Usually, in order to perform a hot or cold rolling process, a continuous annealing process, a continuous plating process, a plurality of rollers, that is, a continuous roll annealing process, a heat roll installed in an annealing furnace and a sink installed in a hot dip bath. Sink Rol1, Mesuring Rol1, Pinch Roll, Bridle Roll, Roof Roll, Process Roll are used at room temperature. do.

These rollers require abrasion resistance, adhesion resistance, corrosion resistance, molten metal corrosion resistance, heat resistance, thermal shock resistance, and oxidation resistance. When the surface hardness of the roller is low, it is easy to cause scratches or the like on the surface of the roller due to the conveyed steel sheet or impurities, and in some cases, the surface of the steel sheet may be flawed.

In view of this point, the roller is used by forming a hard chromium plating layer on its surface. This hard chromium plated layer has a high hardness and wear resistance, but the separation characteristics of foreign substances such as fine iron, which is transferred from the surface of the steel sheet to the roller, are not good.

The proposed solution to solve the drawbacks due to chromium plating is tungsten carbide spray coating, but since tungsten carbide alone does not adhere well to the surface of the roller, a mixture of carbide and metal using cobalt or nickel as a metal binder is generally used. I use it in a state. In addition, when used in a humid atmosphere or at an atmosphere of up to 550 ℃, a metal containing chromium, such as nickel-chromium, cobalt-chromium, is used as the metal binder. Since the tungsten carbide-based coating has a higher hardness than hard chromium plating, the wear resistance is more excellent, and ceramics, not metals, have a main component, so that foreign substances such as fine iron do not adhere well to the surface.

Thermal spray coating can be classified into flame, electric arc, plasma, and explosion spray according to the heat source for melting the coating material. Among them, the flame spray method is the most traditional method using oxygen-acetylene as the heat source. Since it is low, it is widely used for coating of aluminum (Al) alloy and zinc (Zn) alloy. In addition, iron (Fe), nickel (Ni), cobalt (Co) -based alloys and the like have a high melting point, which lowers the coating properties, so its use is very limited. Here, the self-soluble alloy is an alloy that adds a small amount of silicon (Si) and boron to the nickel (Ni) or cobalt (Co) system to lower the melting point to about 1000 ° C. to facilitate thermal spray coating. (Si) is added in a weight ratio of about 3-5% and boron 1-4%. Thermal spray coating of such a magnetic alloy still causes about 10-20% of pores in the tissue and inadequate adhesion to the base material, thereby easily peeling off the coating during use.

On the other hand, a powder for forming a thermal spray coating for forming on the surfaces of sink rollers and support rollers used in hot dip galvanizing baths and hot dip galvanized aluminum baths is disclosed in Japanese Laid-Open Patent Publication. 9-268361, 9-227243, and 8-104969. Japanese Laid-Open Patent Publication No. 9-268361 discloses a thermal spraying powder containing a predetermined amount of boron, cobalt, chromium, and tungsten, respectively. -227243 discloses a thermal spray powder containing a predetermined amount of molybdenum boride, nickel, chromium and a predetermined metal boride. Japanese Patent Application Laid-Open No. Hei 8-104969 discloses a thermal spray powder composed of nickel and molybdenum complex boride and nickel, and also discloses a thermal spray powder composed of cobalt and molybdenum composite boride and cobalt. have.

The thermal spray coating formed using the thermal spraying powders disclosed in Japanese Patent Application Laid-Open Nos. Hei 9-268361 and Hei 9-227243 has not very high melting metal corrosion resistance, heat resistance, heat shock resistance, oxidation resistance and abrasion resistance. Moreover, even if the thermal spraying powder disclosed by Unexamined-Japanese-Patent No. 8-104969 is used, the thermal spray coating which is excellent in solvent-resistant metal corrosion resistance, heat resistance, thermal shock resistance, oxidation resistance, and abrasion resistance cannot be obtained reliably.

Korean Unexamined Patent Publication No. 85-7742 discloses a method for producing a metal sintering agent, and Japanese Unexamined Patent Publication No. 2004-167599 discloses a conveying roll.

An object of the present invention is to solve the problems as described above, has a metallurgical form that is not sintered and fusion, and not alloyed to form a self-soluble spray alloy powder and a thermal spray coating film using the same to increase the wear resistance and friction coefficient The purpose is to provide a roller.

Soluble thermal spray alloy powder of the present invention for achieving the above object,

A mixture of at least one selected from Fe, Fe alloy, Mo, Mo alloy, Cu, Cu alloy, Al, Al alloy, Zn, Zn alloy powder based on 100 parts by weight (wt) of nickel-based or cobalt-based magnetic powder is 2 to It is characterized by that it contains 25 parts by weight.

In the present invention, carbide powder, ceramic powder, and cermet may be further included, wherein the carbide powder is 5 to 60 parts by weight based on 100 parts by weight of nickel-based or cobalt-based water-soluble powder, and the ceramic is 0.5 to 40 parts by weight is included.

In order to achieve the above object, a roller having a thermal spray coating according to the present invention includes a roller main body supported on a rotating shaft, and a thermal spray coating film formed by spraying a magnetically soluble thermal spray alloy powder on the outer circumferential surface of the roller body. A silver spray alloy portion and a mixture bonding portion distributed in the spray alloy portion and having a metallurgical bonding form.

In the present invention, the magnetic soluble spray alloy powder is Fe, Fe alloy, Mo, Mo alloy, Cu, Cu alloy, Al, Al alloy, Zn, based on 100 parts by weight (wt) of nickel-based or cobalt-based magnetic powder 2 to 25 parts by weight of a mixture of at least one selected from the Zn alloy powder is included, and carbide is included in an amount of 5 to 60 parts by weight and 0.5 to 40 parts by weight based on 100 parts by weight of nickel or cobalt based magnetic powder.

Hereinafter, with reference to the accompanying drawings will be described in detail an embodiment of a self-soluble spray alloy powder and a roller formed with a spray coating film using the same.

A roller for performing a hot or cold rolling process, a continuous annealing process, a continuous plating process, or the like requires wear resistance, sinter resistance, corrosion resistance, molten metal corrosion resistance, heat resistance, thermal shock resistance, and oxidation resistance. In the case of a specific hot rolling line, a friction force between the steel sheet and the roller surface is required because the steel sheet must be moved at a uniform speed using a roller. In particular, since the production of the steel sheet by hot rolling is made at an extremely high speed, a roller of good quality is required to increase the quality of the steel sheet.

In view of this point, the roller according to the present invention is to increase such friction force, and as shown in FIG. 1, the roller body 12 having the rotating shaft 11 and the outer circumferential surface of the roller body 12 are self-soluble. The thermal spray coating layer 20 is formed by spray coating using a spray alloy powder, the spray coating layer 20 is a thermal spray alloy portion 21, the mixture 22a is distributed in the thermal spray alloy portion 21 is metallurgical Mixture coupling portion 22 having a coupling form.

The self-soluble spray alloy powder for forming the thermal spray coating film 20 is Fe, Fe alloy, Mo, Mo alloy, Cu, Cu alloy, Al, Al alloy, based on 100 parts by weight (wt) of nickel-based or cobalt-based powder A mixture of at least one selected from Zn and Zn alloy powders contains 2 to 25 parts by weight. The iron alloy is Fe-Mo, Fe-Mn, Fe-Si, Fe-Al, Fe-W, Fe-p, Fe-Zr, Fe-v, Fe-Co, Fe-C, Fe-Cu, Fe- Ni, Fe-Cr and the like. And the Cu alloy may be made of Cu-B, Cu-Si, Cu-W, Cu-Al, Cu-Mn, Cu-Sn, Cu-Zn, Cu-Mo and the like.

On the other hand, the water-soluble spray alloy powder may further include carbide powder, ceramic powder, cermet (cremat) to increase the wear resistance, the carbide is 50 to 60 parts by weight based on 100 parts by weight of nickel or cobalt-based powder, It is preferable that the ceramic contains 0.5 to 40 parts by weight. When the carbide is mixed to 50 parts by weight or less or the ceramic to 0.5 or less, the porosity is lowered and the abrasion resistance cannot be improved, and when the carbide is mixed by 60 parts by weight or the ceramic by 40 parts by weight or more, brittleness becomes high. The desired physical properties could not be obtained.

As described above, the thermal spray coating film 20 formed using the magnetically soluble spray alloy powder may be formed of Fe, Fe alloy, nickel or cobalt magnetic powder (see KS Standards and JIS Standards), as shown in FIGS. 2 and 4. Melting temperature of the magnetically soluble spray alloy powder because at least one selected from Mo, Mo alloy, Cu, Cu alloy, Al, Al alloy, Zn, Zn alloy powder, and cermet or ceramic is composed of a mixture 22a When the mixture 23 is heated to the furnace temperature to form a coating layer, the mixture 23 is metallurgically bonded to the surface layer and easily corrodes, thereby presenting the mixture coupling portion 22 forming pores or irregularities in the surface layer. Therefore, the coefficient of friction of the surface of the roller body 12 can be increased.

In particular, since the mixture bonding portion 22 inside the thermal spray coating film maintains a coating-free bond state by the thermal spraying alloy portion 21 as shown in FIGS. 3 and 4, cracking or peeling does not occur at high temperature or high load. Will not.

This action will be clearer through the following experiment.

Experiment 1

In this experiment, the spray coating layer was formed on the surface of the roller body by using high velocity oxygen spraying method using nickel- or cobalt-based powder of magnetically soluble spray alloy powder prepared by iron content. And hardness change were measured to obtain the following Table 1 and Table 2. Here, KSD8322 (JISH0303) was used as the magnetic alloy, and carbon steel KSD3517 and S45C for friction material structures were used, and the Fe used in the mixture was 99% pure iron powder.

As can be seen from Tables 1 and 2, it can be seen that the friction coefficient is not significantly increased in the iron powder content of 2% or more, and the hardness (HRC) is drastically lowered at 25% or less of the iron powder. Could. When the hardness is lowered, since the surface of the roller body is sharply reduced, it is difficult to apply when the iron powder content is less than 25%. In addition, the above results showed that the same tendency was observed in the iron alloy, Cu alloy, Al alloy, and Zn alloy.

Experiment 2

In the present experiment, a spray coating layer was formed on the surface of the roller body by using a high velocity oxygen spraying method on the surface of the roller body by using a spray powder prepared for each molybdenum content in nickel- or cobalt-based powder insoluble under the same conditions as in Experiment 1. The friction coefficient and hardness change were measured to obtain the following Tables 2 and 3. The molybdenum powder as a mixture used 99% pure molybdenum powder.

As can be seen from Table 3 and Table 4, the friction coefficient does not significantly increase in the molybdenum content of 2% or more, and the hardness (HRC) shows that the molybdenum content is drastically lowered at 25% or less. Could. And it can be seen that the above results show the same tendency in the molybdenum alloy.

In particular, when the content of molybdenum is too high, the toughness and adhesion of the thermal sprayed coating were significantly reduced. Could know.

As described above, the roller having the insoluble thermally sprayed alloy powder of the present invention and the coating film using the same has a property inherent to the mixture because the mixture is not alloyed and remains in a metallurgical bonding state. Therefore, no cracking or peeling occurs at high temperatures or high loads. And by forming a porous protrusion by the corrosion of the mixture to improve the coefficient of friction, it was possible to improve the wear resistance 10 times or more than conventional. In particular, even in the high hardness soluble spray alloys of Hs70 to Hs100, which are generally considered as impossible, they have a high coefficient of friction of about 0.3.

   Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent embodiments are possible.

Therefore, the true scope of protection of the present invention should be defined only by the appended claims.

Claims (5)

Mixture of at least one selected from Fe, Fe alloy, Mo, Mo alloy, Cu, Cu alloy, Al, Al alloy, Zn, Zn alloy powder based on 100 parts by weight (wt) based on nickel or cobalt based powder Soluble thermal spray alloy powder, characterized in that it comprises from 25 parts by weight. The method of claim 1, The carbide powder, the ceramic powder, and a soluble thermal spray alloy, characterized in that it further comprises a cermet. The method of claim 2, The carbide is a magnetic flux spray alloy powder, characterized in that 5 to 60 parts by weight, ceramic powder is 0.5 to 40 parts by weight based on 100 parts by weight of nickel-based or cobalt-based magnetic powder. A roller body supported on a rotating shaft, and a thermal spray coating layer formed by spraying a magnetic alloy spray powder on the outer circumferential surface of the roller body, the thermal spray coating layer is distributed in the thermal spray alloy portion and the thermal spray alloy portion, the metallurgical coupling form A roller comprising a porous forming portion having a. The thermal spray powder is at least one selected from Fe, Fe alloy, Mo, Mo alloy, Cu, Cu alloy, Al, Al alloy, Zn, Zn alloy powder based on 100 parts by weight (wt) based on nickel or cobalt based magnetic powder 2 to 25 parts by weight is included, carbide is 5 to 60 parts by weight based on 100 parts by weight of nickel or cobalt based magnetic powder, ceramics characterized in that it comprises 0.5 to 40 parts by weight.

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