JPS6335764A - Surface treatment of iron or iron alloy material - Google Patents

Abstract

PURPOSE:To form a carbonitride layer of V having high resistance to wear, seizure, oxidation, corrosion, etc., on the surface of an iron metallic material by subjecting said metallic material to a heating treatment in the co-presence of a V-contg. material, cyanide and other specific treating materials. CONSTITUTION:The iron or iron alloy material for dies, metallurgical tools, mechanical parts, etc., is made to co-exist with the V-contg. raw material such as metallic V, V alloy or VCl3, VF5 or V2O5, cyanide and cyanate of alkali metal or alkaline earth metals such as NaCN or KCNNaCNO or further the fine powder treating materials NaCl, CaCl2, NaF, Na2CO3 and other chloride, borofluoride, fluoride, oxide, bromide, iodide, carbonate, nitrate, and borate of alkali metal or alkaline earth metals. The material is subjected in this state to the heating treatment at <=650 deg.C to diffuse and penetrate V, N and C into the surface of the iron metallic material. The layers of the V carbide, V nitride and V carbonitride having various excellent characteristics are formed on the surface of the iron metallic material.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides a method for forming a carbonitride layer of vanadium (V) on the surface of iron or iron alloy materials such as molds, jigs, and machine parts. This relates to a processing method.

[Conventional technology]

When the surface of iron or iron alloy material (hereinafter referred to as the treated material) is coated with a surface layer consisting of vanadium carbide, nitride, or carbonitride, the wear resistance, seizure resistance, and oxidation resistance of the treated material are improved. It is well known that various properties such as corrosion resistance are improved. Many proposals have been made in recent years regarding methods of coating this surface layer. For example, a method has been proposed in which a vanadium carbonitride surface layer is formed on the surface of a treated material by plasma CVD (chemical vapor deposition) using a vanadium halide (e.g. , JP-A-55-65357, JP-A-Sho 55
-154563). In these methods, since the treatment is carried out at a temperature range below approximately 700"C, which is the A (1 transformation point) of iron,
Although it is possible to form a surface layer without imparting thermal distortion to the base material of the material to be treated, it is difficult to obtain a formed surface layer with good throwing power and adhesion.

In addition, the processing steps are complicated and the equipment is expensive. Also.

It is also inefficient because it must be carried out in hydrogen or under reduced pressure.

[Problem that the invention seeks to solve]

The present invention solves the above-mentioned conventional problems and efficiently heats the workpiece at low temperatures using extremely simple equipment. The present invention aims to provide a method for forming a surface layer made of vanadium carbonitride with excellent properties.

[Means for solving problems]

The first invention coexists an iron or iron alloy material, a material containing vanadium, and a treatment agent consisting of one or more of cyanide salts and cyanates of alkali metals or alkaline earth metals. Forgive me.

Vanadium by heat treatment at 650°C or less.

A method for surface treatment of iron or iron alloy material, comprising forming a surface layer made of vanadium carbonitride on the surface of iron or iron alloy material by diffusing nitrogen and carbon onto the surface of the iron or iron alloy material. It is.

The second invention provides an iron or iron alloy material, a material containing vanadium, one or more of cyanide salts and cyanates of an alkali metal or an alkaline earth metal, and an alkali metal or an alkaline earth metal. Metal chlorides, boron fluorides, fluorides, and oxides.

One of bromide, iodide, carbonate, nitrate, or borate
or a treatment agent consisting of two or more types,
A surface layer made of vanadium carbonitride is formed on the surface of the iron or iron alloy material by heat treatment at 50° C. or lower to diffuse vanadium, nitrogen and carbon onto the surface of the iron or iron alloy material. This is a surface treatment method for iron or iron alloy materials.

In the present invention, the iron or iron alloy material is the material to be treated on which a vanadium carbonitride layer is formed. Examples of the iron or iron alloy material include those containing carbon 9, such as carbon steel 1
It may be made of alloy steel, cast iron, sintered alloy, or the like, or it may be made of something that does not contain carbon at all, such as pure iron. In addition, it is not necessary that nitrogen be included, but there is no problem even if it is included.

In the present invention, the heat treatment in which the above-mentioned material to be treated, a material containing vanadium, and a processing agent are made to coexist and heated is performed by:
A surface layer made of vanadium carbonitride is formed by diffusing vanadium, nitrogen, and carbon onto the surface of the material to be treated.

Furthermore, as described in the following operations, the surface layer formed of vanadium carbonitride is the layer (outer layer) consisting of vanadium-based carbonitride, and the carbonitride layer of iron immediately below the layer (outer layer). There are two layers: a layer made of objects (inner layer). Also,
A solid solution layer (diffusion layer) of nitrogen in iron is formed directly below the iron carbonitride layer (inner layer).

The vanadium-containing material is one that supplies vanadium to be diffused onto the surface of the material to be treated.

A metal containing vanadium or a vanadium compound is used. Examples of the metal include metal vanadium and alloys thereof. The above compound includes VCl 3+ V F
Examples include chlorides, bromides, oxides, etc., such as VzOs and VzOs. However, these vanadium-containing materials are
One or more of these may be used, but it is most practical to use vanadium metal or iron-vanadium alloy.

Further, the processing agent has the function of supplying nitrogen and carbon to be diffused onto the surface of the material to be treated and serving as a medium for vanadium to diffuse onto the surface of the material to be treated. As the treatment agent, one or more types of cyanide salts and cyanates of alkali metals or alkaline earth metals (hereinafter referred to as the first
The first treating agent may be a chloride or fluoride of an alkali metal or an alkaline earth metal.

Borofluorides, oxides, bromides, iodides, carbonates.

One or a mixture of two or more of nitrates and borates (hereinafter referred to as the second treatment agent) may also be used. Note that the first treatment agent supplies nitrogen and carbon that diffuse to the surface of the iron alloy material. It also has the function of adjusting the melting point, viscosity, evaporation amount, etc. of the second processing agent and increasing the stability of the processing, and is appropriately selected and used depending on the heat processing method.

For example, as the first treatment agent, NaCN, KCN, Na
CN0. Examples include KCNO, and one or more of these may be used.

Further, as the second treatment agent, NaCl, KCI.

CaC1zlLiC1, NaF, KF, LiF, KB
F * + N az COs + L I CO3
1K CO: l l N a N 03, N a z
o, etc., and one type or two or more layer types of these are used.

What is the mixing ratio of the processing agent and the material containing vanadium?

It is desirable that the treatment agent be used in an amount of 0.5 to 30% by weight (hereinafter 1% by weight is referred to as %) based on the vanadium-containing material.

If it is outside this range, it will be difficult to form a continuous surface layer, and if it approaches the center of this range.

Continuous surface layer formation tends to be easier.

Heat treatment methods include molten salt immersion method, molten salt electrolysis method,
There are paste methods etc.

These will be explained below.

The molten salt immersion method is a method in which the processing agent is melted to form a molten salt bath, and the vanadium-containing material and the material to be treated are immersed in the molten salt bath.

Immersing the vanadium-containing material in the molten salt bath is
This is to dissolve vanadium into the molten bath salt. As a means of dissolving vanadium.

A method of adding the material to a molten bath in the form of a powder (preferably 200 mesh or less) or a thin plate, or a method of immersing the material in the form of a rod or plate as an anode in a molten bath and electrolyzing it to dissolve vanadium in the anode, etc. be. The rate at which vanadium dissolves into the molten salt from the vanadium-containing material varies depending on the type and size of the vanadium-containing material used. It is necessary to maintain the temperature at 7!! When vanadium is infused by the above-mentioned anodic melting, vanadium can be infused quickly and work efficiency can be improved, and furthermore, material containing undissolved vanadium will not be deposited on the bath bottom. It's advantageous. In this case, as the cathode, a conductive substance inserted into a molten salt bath container or elsewhere is used. Increasing the anode current density during anodic melting will increase the infiltration rate, but a relatively low current density is sufficient considering that even if no electrolysis occurs (even if infiltration occurs), a relatively low current density is sufficient. is 0.1~
0.8 A/cal is suitable.

The vanadium dissolved in the bath diffuses onto the surface of the material to be treated together with nitrogen and carbon supplied from the treatment agent to form a surface layer made of vanadium carbonitride.

Note that graphite, steel, or the like is used as the container for the molten salt bath, but steel is sufficient for practical use.

In addition, the molten salt electrolysis method is a method in which a material containing vanadium is immersed in a bath in which a treatment agent is melted, and the material to be treated is immersed in the molten salt bath as a cathode in a state in which vanadium is infused, and electrolytic treatment is performed. In this case, the bath container or a separately inserted conductive material is used as the anode.

A method similar to the molten salt immersion method described above may be used to infuse vanadium by immersing a material containing vanadium in a bath in which a processing agent is molten. Further, electrolytic treatment can also be performed by immersing a vanadium-containing material in a molten salt bath of a treatment agent as an anode and a material to be treated as a cathode. In this case, there is an advantage that the anodic melting of vanadium and the formation of the surface layer can be performed simultaneously.

Further, the cathode current density at which the material to be treated is immersed for electrolytic treatment is preferably 2 A/cal or less, and practically 0.05 to 1° OA/crA.

Incidentally, both the molten salt immersion method and the molten salt electrolysis method described above can be carried out either in the air atmosphere or in a protective gas (Nz+Ar, etc.).

The paste method is a process in which a mixed powder of the treatment agent and a material containing vanadium, or a treatment agent in which vanadium has been infused as described above, is cooled and solidified, and then ground into a paste and coated on the material to be treated. It is then heated.

In order to form the powder into a paste, an adhesive such as an aqueous dextrin solution, glycerin, water glass, ethylene glycol, or alcohol is added. This powder paste is usually coated on the surface of the material to be treated to a thickness of one layer or more. The paste-coated iron alloy material is usually placed in a container and heated in a heating furnace. The atmosphere may be air, but the paste coating layer can be made thinner in a non-oxidizing atmosphere.

Further, in this paste method, since the surface layer is formed only on the surface portion covered with the paste, the surface layer can be formed only on an arbitrary part of the surface portion of the material to be treated.

Further, the particle size of this powder may be such that it can pass through a JISI'klOO sieve. Whether it is coarser or finer than this, there is no particular effect.

The heating temperature of the above heat treatment is 650° C. or lower. By processing in a temperature range of 650° C. or lower, the base material of the material to be processed is less susceptible to distortion.

Further, it is desirable that the lower limit temperature is 450°C. When heat treatment is performed at a temperature lower than 450° C., the rate of formation of one surface layer is very slow. Practically speaking, the high temperature tempering temperature for die steel is preferably 500 to 600°C, which is the tempering temperature for structural steel.

As the heat treatment time becomes longer, the thickness of the surface layer (the carbonitride layer mainly composed of vanadium and the iron carbonitride layer directly below it) increases; The vanadium content in the carbonitride layer increases as well. Therefore, the treatment time is determined by the desired thickness or vanadium content of the surface layer, and is selected within the range of 1 to 50 hours.

In addition, the thickness of the surface layer to be formed is about 3 to 15 μm or 2
The practical thickness of the carbonitride layer containing vanadium as a main component in the surface layer is about 1 to 10 μm. If the thickness exceeds this, there is a risk that the toughness of the material to be treated will decrease.

[Effect]

The formation mechanism of the surface layer made of vanadium carbonitride according to the present invention is not clear, but as judged by the present inventors from X-ray diffraction, microanalyzer analysis, and the relationship between processing time and thickness, it is as follows. (The following m, n, o, and p each represent a number).

First, nitrogen (N) and carbon (C) diffuse into the iron or iron alloy material to be treated from the outside and react with iron (Fe) on the surface of the treated material to form Fe and (C).

A nitride layer is formed in the form of N), . Note that if the material to be treated contains carbon (C) or nitrogen (N), this carbon or nitrogen (N) also becomes Fe or (C).

N) Included in 7. A solid solution of nitrogen (in the form of Fe--N) is also formed directly below this nitride layer.

These reactions proceed from the surface to the interior.

Immediately thereafter, the nitride layer is exposed to external vanadium (V).
) begins to diffuse, and the above two reactions proceed in parallel. . This diffusion is F e m (C.

It is a reaction in which Fe of N) and ' is substituted with ■, and the nitriding physics is (V, Fe). (C,N)p, and the reaction progresses gradually from the surface to the inside. In addition, (■.

Fe). In the (C,N) p layer, the surface tends to have more V, and the closer it is to the base material, the more Fe there is. Therefore, depending on the conditions, the amount of Fe in the surface portion is extremely small.

■. (C, N) may be appropriate.

Therefore, the surface layer formed is (V, Fe) on the surface side.
. A layer of (C,N) is formed, and further Fe, (C
, N)-N is formed.

Furthermore, in addition to the above-mentioned reaction, a reaction in which (1) and N or (2), N, and C are directly deposited on the surface of the treated material may also be occurring at the same time.

This (V, Fe). (C,N)p layer and Fe, (C.

N), The thickness of the layer and the solid solution layer of iron and nitrogen, as well as the ratio of the thickness and the chemical composition, can be adjusted by the type of base material, the treatment temperature for 2 hours, the mixing ratio of the two types of treatment agents, etc. It is.

2. The present inventors previously proposed a surface treatment method for a treated material made of an iron alloy material, in which a surface layer made of a nitride or carbonitride of a Group Va element of the periodic table was formed on the surface of the treated material. Invented a surface treatment method characterized by
I would like to apply for this patent application No. 1987-17'8781). this is,
After performing nitriding treatment to form an iron/nitrogen or iron/carbon/nitrogen compound layer on the surface of the treated material, the treated material, a material containing a Group Va element, and an alkali metal or alkaline earth metal Treatment consisting of one or more of chlorides, fluorides, borate fluorides, oxides, bromides, iodides, carbonates, nitrates, borates, or one or both of ammonium halides and metal halides. A heat treatment is performed at 580° C. or lower, and
By diffusing Group A elements into the compound layer formed by the above nitriding treatment, Va.
This is a surface treatment method (hereinafter referred to as a two-time treatment method) characterized by forming a surface layer consisting of a nitride or carbonitride of a group element.

In the present invention and the previous two-step processing method, a salt bath method or a paste method is used at a low temperature to prevent distortion due to heat.

Although they are similar in that a surface layer made of vanadium carbonitride is formed on the surface of the material to be treated, they differ greatly in the following points.

(A) Mechanism of carbonitride layer formation In the two-step treatment method, iron-nitrogen and iron-carbon-nitrogen compound layers are formed in the first treatment, and group Va elements and the above nitrides are formed in the second treatment. By a substitution reaction with iron in the layer, Va.
A group element nitride layer and a carbonitride layer are formed. Therefore, what is the maximum thickness of the surface layer that can be formed on the nitrided material?

It is the same as the thickness of the iron-nitrogen and iron-carbon-nitrogen compound layers formed in the first treatment, and therefore the thickness of the surface layer is defined by the first nitriding treatment.

On the other hand, in the present invention, as shown in the later examples, 1
Both the vanadium-based carbonitride layer on the surface side and the iron carbonitride layer on the base metal side tend to be thick in proportion to the square of the processing time.

(B) Characteristics of treated materials Although the hardness, abrasion resistance, and seizure resistance of the formed layers are about the same, there is a large difference in the toughness of the treated materials.

In general nitriding treatment, 1.
Usually, the surface is treated to prevent the formation of a compound layer. On the other hand, in the two-step processing method previously applied for, it is necessary to form a thick compound layer, and accordingly, a thick iron/nitrogen solid solution layer is also formed. The results of the X″!fA!fA microanalyzer analysis shown in the examples also clearly show that a large amount of nitrogen is solidly dissolved in the base metal, and these have an adverse effect on the toughness of the base metal.

In the treatment according to the present invention, the amount of solid solution of nitrogen in the base material is extremely small, and the solid solution layer of iron and nitrogen is also thin, as seen in the later examples, compared to the case of the two-time treatment method. Therefore, 2
It is considered that the material to be treated according to the present invention has higher toughness than the material to be treated by the reprocessing method.

(C) Processing Efficiency In contrast to the two-step processing method, which requires two different treatments, the processing method of the present invention allows the formation of a layer in one processing. Therefore, in addition to high processing efficiency, it has the advantage of requiring less equipment.

〔Effect of the invention〕

According to the present invention, since the vanadium diffusion treatment is performed at a low temperature of 650° C. or lower using the above-mentioned specific treatment agent, an excellent surface layer consisting of vanadium carbonitride is formed on the iron or iron alloy material at low temperature. can do.

Additionally, since the iron or iron alloy material is heated at low temperatures, distortion is less likely to occur in the base material. Furthermore, it has good operability due to low temperature treatment and does not require a large amount of energy.

9 Also, since the layer according to the present invention is formed by diffusion,
PVD with no diffusion reaction despite processing at low temperatures
Unlike the case of carbide and nitride layers, it has excellent adhesion to the base material and can form a dense surface layer. Moreover, the thickness of the formed layer is practically sufficient.

〔Example〕

Two aspects of the present invention will be described in detail below.

Example 1 NaCN053wt%, KCl12wt% and Caclz
A heat-resistant container containing the mixture with 35 wt% was heated in an electric furnace in the atmosphere to form a 570°C molten salt bath, and
00 mesh ferrovanadium (Fe-V, JISI
15 wt % of the powder was added to the molten salt bath.

This molten salt bath has a diameter of 61). JIS-SK with length of 20 cranes
After immersing the H51 round bar test piece for 1 to 50 hours, it was taken out and air cooled. After washing and removing the adhering solvent, the cross section was polished and the cross-sectional structure was observed. - As an example, a micrograph of a cross-sectional m weave of the surface layer formed by immersion treatment for 8 hours (magnification: 100
times) are shown in Figure 1. The surface layer has a smooth surface and consists of two layers: an inner layer and an outer layer. The cross section of this sample was analyzed using an X-ray microanalyzer.

As shown in Figure 2, the surface layer contains N, along with V and Fe.
,! :C is observed, V and N are found in the outer layer, and Fe is found in the inner layer.
- and C were detected in large numbers. In addition, N into the base material directly below the first layer
The amount of solid solution is extremely small. According to the analysis results from the surface, approximately 50% Vi exists, and furthermore, X-ray diffraction shows that V C
, V N , and diffraction lines corresponding to Fe 3C were observed. The surface layer formed from this has an inner layer of Fe, (
An iron carbonitride layer consisting of (C, N), the outer layer is (V,
Fe). It was confirmed that it was a vanadium-iron carbonitride layer consisting of (C,N)p. Soaking time
Curves A and B in FIG. 3 show the results of measuring the thickness of the layer formed on the 5 surfaces by observing the cross-sectional structures of test specimens treated in four different ways for 1 to 50 hours. Here, 2 curves A
is the inner layer (F e, (C,N),, layer) and the outer layer ((V,
Fe). (C,N), layer] curve B indicates the thickness of the outer layer, and the total thickness of the inner layer and outer layer, as well as the thickness of the outer layer, increase approximately in proportion to the square of the processing time. It was a trend.

In addition, in order to examine the adhesion of the layers formed in the two examples,
Using a Rockwell hardness meter, an indenter was dropped under H*C measurement conditions, and changes appearing around the indentation were observed. Result 9
In the layer formed by this process.

Tensile stress was applied to one layer due to the swelling of the base material around the indentation, and about 10 cranks were generated in a radial pattern, but no peeling of the three layers was observed, indicating good adhesion. On the other hand, for comparison, a similar test was conducted on a TiN layer formed by ion blating, and the results showed that the layer around one layer was completely peeled off in an annular shape. Also, 7 formed in a molten salt bath at 1000°C
In layer 0, cranks similar to those in the layer of this example were observed.

Example 2 NaCNO57wt%, NaCN13wt% and NaCl
A heat-resistant steel container containing a mixture of 9 wt% CaCIz and 21 wt% CaCIz was heated in an electric furnace in the atmosphere to form a molten salt bath at 550°C, and VCt, powder (-320
To this molten salt bath to which 15wt% of methane) was added to the molten salt bath, a JIS-34
After the 5C round bar test piece was purified for 8 hours, it was taken out and cooled in the air.

A micrograph (400x magnification) of the cross-sectional structure of the test piece is shown in the fourth photo.
As shown in the figure. The layer formed on the surface consists of two layers as in Example 1, based on the results of X-ray diffraction and X-ray microanalyzer analysis shown in FIG.

As in the case of Example 1, the inner layer is Fe, (C, N).

Iron carbonitride layer consisting of (V,Fe).

It was confirmed that it was a vanadium-iron carbonitride layer consisting of (C,N).

In addition, the adhesion evaluation using a Rockwell hardness test showed the same cracking pattern as in Example 1, and it was determined that the layer had good adhesion.

Example 3 The same NaCN053wt% and KC used in Example 1
A graphite container containing a mixture of l12wt% and CaCIz 35wt% was heated in an electric furnace in the atmosphere and maintained at 570°C, and a 60x30x4m plate-shaped Fe-V (JISI No.) was placed in the center of the bath. With this as an anode and the graphite container as a cathode, electricity was applied at an anode current density of 0.6 A/cnl for about 16 hours. Calculating from the weight reduction of the Fe-V plate, this anodic dissolution treatment reduces the total amount of salt bath by about 6
% of vanadium was taken into the bath. In this molten salt bath, two S K H51 round bar test pieces with a diameter of 6 mm and a length of 15 mm were placed.
After being immersed for 4 hours, it was taken out and cooled in the air.

When the treated specimen was cut and examined using an optical microscope and an X, l microanalyzer analysis, the surface layer was formed into two layers, and as shown in Figure 6, the surface layer contained N along with V and Fe. (!:c was observed, V and N were detected in the outer layer, and Fe and C were detected in large amounts in the inner layer. Also, in the X-ray diffraction results, diffraction lines corresponding to VC, VN, and FeffC were observed. .

As for adhesion, good results were obtained as in Example 1.2.

Example 4 NaCNO51wt%, NaCl21wt% and NazC
A graphite container containing a mixture of O*28 wt% was heated to 570°C in an electric furnace in the atmosphere to prepare a molten salt bath, and 1100 Mesosh Fe-V (JISI No.) was added to this bath.
The powder was added at 20% relative to the molten salt. A 545C specimen with a diameter of 8 inches and a length of 20 fins was immersed in this 570°C bath.
This is the cathode.

Cathode current density 0.05A/cff with graphite container as anode
Electrolytic treatment was carried out by applying a J electric current for 8 hours.

The specimen was taken out of the bath, cooled in air, cut, and the structure of the cross section was observed using an optical microscope. A microscopic photograph of the cross-sectional structure of the surface layer is shown in FIG. As in the case of other examples, the surface layer consists of an outer layer and an inner layer of 2N, and as shown in FIG.
In the inner layer, much Fe and C were observed. This result was also similar to other examples.

Example 5 NaCNO45wt%, KCll0wt% and CaC1z
25 wt% and 2 Qwt% of Fe-V (JISI No.) powder were heated to 650°C, and the molten bath was thoroughly stirred to make it uniform. 1 part of graphite and alumina powder were each added to 4 parts by weight of this bath. Parts by weight were added and thoroughly mixed to prepare a processing agent for slurry coating.

Thereafter, the processing agent was cooled and made into a powder, and then ethyl alcohol was added to form a slurry.

This was applied to 345C to a thickness of about 5 mm and dried. The above sample was heated at 570° C. for 8 hours in a nitrogen atmosphere and then cooled.

After removing the treatment agent adhering to the sample, examination using X-ray diffraction and an X-ray microanalyzer revealed that, as in Example 1, a two-layer surface layer was formed, and the inner layer was pe, (C,N)n.
Iron carbonitride layer consisting of (V,Fe). (C,
N) It was confirmed that it was a vanadium-iron carbonitride layer consisting of p.

Example 6 Same as used in Example 1, NaCN053wt%, KCl12wt%, CaClz35wt%
A heat-resistant container containing a mixture of ferrovanadium (F e -V) was heated in an electric furnace in the atmosphere to form a molten salt bath of 570"C, and 100 mesohydrium of ferrovanadium (F e -V) was formed.

JISI No.) powder was added at 15 wt % to the molten salt bath. An SK■ (5-layer specimen) having a diameter of 6.5+n and a length of 4Q++a, which had been quenched and tempered under standard conditions in advance in this molten salt bath, was immersed for 8 hours, then taken out and cooled in the air.

After washing and removing the adhering bath agent, the formed surface layer was examined by X-ray diffraction, and diffraction lines corresponding to VC, VN, and Fe3C were observed.

Next, the above-mentioned vanadium carbonitride coated specimen (sample size 1) was dry-tested using a Fabry tester using gas carburized and quenched JIS-3CM415 as a mating material under a load of 200 kg.
A friction test was conducted under the following conditions: rotation speed 30 rpm, friction speed 0.1 m/sec, and test time 4 min. In addition, for comparison, JIS-3KH51 quenched and tempered specimens (sample 1
) hsl) and a 5KH51 specimen (sample 1lhs 2) which had been subjected to only nitriding treatment were also subjected to similar friction tests.

The specimen of sample Nll5I showed a wear amount of about 17 B/cal, and the friction coefficient measured 30 seconds after the start of the test was 0.
．． It was 280. In addition, the specimen of sample Nl52 is approximately 15 m long.
The wear amount was g/c4, and the friction coefficient 30 seconds after the start of the test was 0.265.

On the other hand, in the sample magnet 1 according to the present example, the amount of wear was as small as about 3 tags 101, and the friction coefficient 30 seconds after the start of the test was as small as O,l 50.

In addition, JIS-5KH51 specimens were coated with a vanadium carbide layer (VC) approximately 3 μm thick by soaking them in a high-temperature molten salt bath at 1020°C for 1.5 hours, or by chemical vapor deposition at 850°C for 4 hours. A similar friction test was conducted on a JIS-3KH51 specimen coated with a titanium carbonitride layer made of Ti (C, N) with a thickness of 8 μm using the vapor deposition method (CVD). The amount of wear and coefficient of friction were almost the same as those of sample fish 1. From this, it can be seen that the surface layer formed by the two examples is not inferior in terms of wear resistance and seizure resistance compared to the surface layer formed by molten salt immersion method or CVD at high temperature.

[Brief explanation of drawings]

Figures 1, 4, and 7 are micrographs (Figure 1: 1000x, Figure 4, 7th
Figure = 400x), Figure 2. FIGS. 5, 6, and 8 show examples 1, 2, and 3, respectively.
4. FIG. 3 is a diagram showing the results of X-ray microanalyzer analysis of the surface portion of the iron alloy material treated according to the present invention; FIG. It is a diagram.

Claims (6)

[Claims] (1) Iron or iron alloy material, material containing vanadium, and cyanide salt of alkali metal or alkaline earth metal,
heat-treated at 650° C. or lower in the presence of a treatment agent consisting of one or more cyanates;
A surface of an iron or iron alloy material, characterized in that a surface layer consisting of vanadium carbonitride is formed on the surface of the iron or iron alloy material by diffusing vanadium, nitrogen, and carbon onto the surface of the iron or iron alloy material. Processing method. (2) iron or iron alloy material, material containing vanadium, and cyanide salt of alkali metal or alkaline earth metal;
One or more cyanates and one of chlorides, fluorides, borate fluorides, oxides, bromides, iodides, carbonates, nitrates, borates of alkali metals or alkaline earth metals Vanadium is added to the surface of the iron or iron alloy material by heat treatment at 650° C. or below to diffuse vanadium, nitrogen and carbon onto the surface of the iron or iron alloy material. A method for surface treatment of iron or iron alloy material, characterized by forming a surface layer consisting of carbonitride. (3) Surface treatment of iron or iron alloy material according to claims (1) and (2), wherein the vanadium material is made of one or more of metal vanadium, vanadium alloy, and vanadium compound. Method. (4) The heat treatment is carried out by immersing the vanadium-containing material and the iron or iron alloy material in a molten salt bath in which the treatment agent is melted. ) Surface treatment method for iron or iron alloy materials. (5) The heat treatment is performed by electrolytic treatment in which the treatment agent is melted and an iron or iron alloy material is used as a cathode in a molten salt bath in which a material containing vanadium is immersed. and a method for surface treatment of iron or iron alloy material according to item (2). (6) The heat treatment is performed in a state where a paste of mixed powder of the treatment agent and a material containing vanadium is applied to the iron or iron alloy material, as described in claims (1) and (2). surface treatment method for iron or iron alloy materials.