KR940003096B1 - Surface hardening process and carbide forming agent of metallic surface - Google Patents

Abstract

The treating material for surface hardening is composed of 10-80 wt.% metal powder of at least one element selectected from group of Cr or Fe-Cr, V or Fe-V, Nb or Fe-Nb and Ti or Fe-Ti; 10-45 wt.% chloride; and 10-45 wt.% boron or boron compound. A binder of 3-30 wt.% added to 100 wt.% treating material is coated on the surface of the treating material powder. The treating material coated with binder is produced in paste form.

Description

Carbide Forming Agent and Surface Hardening Method on Metal Surface

1 is a micrograph of a micrograph of a carbide layer formed according to the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface for forming a carbide layer on the surface of metal materials, such as metals and alloys. In particular, metal surfaces such as chromium (Cr), vanadium (v), titanium (Ti), and niobium (Nb) are treated materials. The present invention relates to a treatment agent and a surface hardening treatment method for forming a carbide layer which is economically and abrasion resistant by penetrating into a simple method.

As the surface hardening treatment method of the metal, carburizing method, nitriding method, boride method, carburizing nitriding method, vacuum plasma coating method, etc. are known, but recently, carbide diffusion hardening method for improving abrasion resistance and impact resistance has been used. The law includes a salt bath method, a powder method, and a gas method. In the salt bath method, iron-chromium, iron-vanadium, iron-titanium, iron-niobium, and the like are added to a salt bath containing borax as a main component to form carbides on the surface of the treated system at a temperature of 950 ° C or higher. However, such a salt bath method requires a special heat-resistant container for use above 950 ° C, and also removes the salts attached to the surface of the target to be treated in the work management, especially a large amount of the salt bath to be treated. Rather, the amount is used a lot, there is a problem when processing a large water treatment agent. The powder method consists of powders such as iron-chromium, iron-vanadium and iron-titanium, and adds a treatment agent to a mixed powder containing alumina powder and chloride or fluoride powder and forms carbide at high temperature of 950 ℃ or higher. That's how to handle it.

However, in such a method, it is difficult to treat a large object, and the processing speed is slow. If the atmosphere is poorly controlled, the treatment agent is oxidatively decomposed at a high temperature and the treatment agent must be frequently exchanged. In addition, as in the salt bath method, a process in which masking, such as plating, is required on a portion that does not need to be coated with carbides is required, and there is a problem in that the amount of powder consumed is larger than the amount of powder consumed.

The gas method is a chemical vapor deposition (CVD) method, in which carbides are formed on the surface of a target by passing gas such as chloride through a gas tightly sealed container at about 1000 ° C. There are drawbacks such as heavy lifting and the need for a separate masking process on the unnecessary parts as mentioned above.

In Japanese Patent Publication No. 43-12971, a technique is known in which various carbides, transition metals, copper salts and mixed powders of alumina are mixed with a caking agent and applied to the surface of the target to be treated.

However, the above-mentioned manufacturing method does not solve the above-mentioned problems and complexity of the process, such as various kinds of compositions, and the applied treatment agent has to be dipped in charcoal powder contained in the iron case and heat-treated.

The present invention provides a surface treatment agent and a surface hardening treatment method capable of providing an inexpensive product and reducing pollution while maintaining a hardness (HV) of the carbide layer of 1,900 or more by performing a rapid diffusion treatment including a process simplification. There is this.

Hereinafter, the present invention will be described.

The present invention can be divided into two processes.

First, the composition of the carbide forming agent is 10 to 10 or more selected from chromium (Cr) or Fe-Cr, vanadium (V) or Fe-V, niobium (Nb) or Fe-Nb, titanium (Ti) or Fe-Ti. As a treatment agent for mixing a metal powder of 80% by weight and 10 to 45% by weight of one selected from ammonium chloride, sodium chloride, potassium chloride, 10 to 45% by weight of borax or boron compound, and secondly, a silicone pressure-sensitive adhesive to the mixed treatment agent of the composition It consists of a process of coating. That is, put an organic solvent such as toluene or alcohol in a container, add 2-30% by weight of a silicone adhesive (ratio to 100% by weight of the treating agent), dissolve it, and add the mixed treatment powder to evaporate the mixed organic solvent. A thin layer of silicone adhesive is coated on the powder surface.

The powder thus prepared is stored in a closed container and used as a surface treatment agent if necessary. At the time of use, for example, an organic solvent, such as toluene or alcohol, is added to the powder prepared as described above to form a paste whose viscosity is adjusted, and it is applied to the surface of the treatment agent in an arbitrary thickness.

By heat-treating the coating agent thus applied at 850-1,200 ° C. for about 30 minutes to 5 hours, each element of the surface treatment agent diffuses into the treatment agent, and mutually bonds with carbon in the treatment agent to form a carbide layer on the surface.

As described above, the properties of metal powders such as chromium, Fe-Cr, vanadium, Fe-V, niobium, and Fe-Nb, which are carbide forming elements, are well known in the present invention, and the reason for their use will be omitted. Ammonium chloride, sodium chloride, and potassium chloride act as accelerators to react with carbide forming metal powder at high temperature to supply metal atoms to the treatment target.

The relative use ratio of the chloride is mutually organic with the metal powder. When the amount of the metal powder is small, the diffusion of metal elements is small, which makes it difficult to form metal carbide and when the amount of the metal powder is too large (over 80% by weight), The amount is small so that metal carbide is not formed uniformly. Similarly, when the amount of chloride added is too large, the metal powder is small, and when too small, the role as an accelerator is insufficient.

In addition, chlorides, for example, ammonium chloride react with oxygen in the air to decompose into nitrogen and hydrides, and chlorine ions react with metal powders to produce metal chlorides to promote carbide reactions. In addition, since it is highly soluble in water after the carbide diffusion treatment, it exhibits a dual characteristic, such as easy removal of the surface coating layer solidified on the surface. Borax or a boron compound serves to promote the reaction of the metal powder and the chloride and forms a liquid film to prevent the loss of metal elements generated at high temperatures.

However, if the amount is too small, its role is insufficient and if it is too large (50% by weight or more), the amount of metal powder and chloride is relatively small, so that it is difficult to form an effective carbon. The temperature and time of the heat treatment are related to the composition, but in the present invention, the reaction of carbide formation is most preferred when the treatment is performed for 30 minutes to 5 hours at 850 to 1,200 ° C.

In addition, the composition of the to-be-processed agent is preferably a higher carbon content, the faster the carbide formation rate and the carbide layer can be made uniform.

As described above, the metal surface coating treatment agent of the present invention can apply the entire treatment target in the form of a paste, and can selectively apply only a portion where a surface hardened layer is required. There is provided a surface treatment agent and a surface hardening treatment method which are not inferior in terms of physical properties as well as inexpensive manufacturing costs such as not required.

The following describes the present invention through examples.

Example 1

The target material having the composition shown in Table 1 (JIS standard S45C, SKS-3, SDD-1) was selected and tested using a surface polished test piece of 10 × 10 × 10 mm.

TABLE 1

The test piece was immersed in Trickle liquid and degreased and dried.

Then, 65% chromium (purity 99.9%) powder, 20% ammonium chloride powder, 15% borax or boron compound were mixed, and then 5% silicone adhesive was dissolved in toluene solvent, and the mixed powder was added thereto to form a paste. This was applied to the surface of the test target, which is the test piece, about 1 mm thick and dried at room temperature. The coated specimen was treated at 1,000 ° C. for 3 hours in an argon atmosphere (Furnace), and then the specimen was cut to measure the film composition and hardness.

The results are shown in (Table 2).

TABLE 2

As shown in Table 2, the present invention showed excellent surface hardness as compared with the conventional invention.

Example 2

Diffusion penetration treatment was carried out in the same manner as in Example 1, using the following treatment agent in the same treatment agent as in Example 1 (Table 1).

Surface treatment agent composition;

The composition, thickness and surface hardness of the carbide layer obtained by the treatment method were shown in Table 3.

TABLE 3

Example 3

Diffusion treatment was carried out in the same manner as in Example 1, using the following treatment agent in the same treatment agent as in Table 1 (Example 1).

Treatment agent composition;

The results are shown in (Table 4).

TABLE 4

Example 4

Diffusion treatment was carried out in the same manner as in Example 1, using the following treatment agent in the same treatment agent as in Table 1 (Example 1).

Surface treatment agent composition;

The results are shown in (Table 5).

TABLE 5

As shown in Examples 1 to 4 it can be seen that the surface hardness (HV) of the present invention is 1,900 ~ 3,400 is superior to the conventional invention. FIG. 1 is a metallographic micrograph formed in Example 1, where a white uniform layer of the to-be-processed agent (B) is a carbide layer.

The thickness of the carbide layer was investigated using the compounding ratio of various compositions in the same manner as in the above example, and the results are shown in Table 6 below.

TABLE 6

Claims (5)

10 to 80 wt% of metal powder and 10 to 45 wt% of chloride, borax or boron compound 10 to 1 or more selected from Cr or Fe-Cr, V or Fe-V, Nb or Fe-Nb, Ti or Fe-Ti A 3 to 30% by weight of the pressure-sensitive adhesive is mixed with respect to the mixture 100% by weight of the mixture of 45% by weight of the treatment agent, wherein the pressure-sensitive adhesive is coated with powder particles of the treatment agent. The metal surface carbide forming agent according to claim 1, wherein the chloride is one selected from ammonium chloride, sodium chloride and potassium chloride. The carbide forming agent of claim 1, wherein the pressure sensitive adhesive is a silicone pressure sensitive adhesive. 10 to 80% by weight of metal powder and 10 to 45% by weight of chloride, borax or boron compound 10 to 1 or more selected from Cr or Fe-Cr, V or Fe-V, Nb or Fe-Nb, Ti or Fe-Ti 3-30% by weight of the pressure-sensitive adhesive with respect to 100% by weight of the mixture of 45% by weight of the mixture is dissolved in toluene, and then mixed with the processing agent to form a paste, which is applied to the metal surface to be treated, and then 850 to 1,200. A carbide forming hardening treatment method for a metal surface, characterized by heat treatment at a temperature of 30 minutes to 5 hours. The method of claim 4, wherein the paste is coated on all or selected portions of the metal surface as the treatment agent.