JP2002088431A - High hardness corrosion resistant alloy member and its production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high hardness corrosion resistant alloy member exhibiting good corrosion resistance to acids, alkalis, salts, or the like, while maintaining characteristics in accordance with use requiring high strength and high hardness including a press molding die and further improved in the wear resistance of a sliding part. SOLUTION: This high hardness corrosion resistant alloy member 3 is provided with an alloy member body 1 composed of an Ni-Cr-Al based alloy having a composition containing Cr in the range of, by mass, 25 to 60% and Al in the range of 0.01 to 10%, and the balance substantially Ni or an Ni-Cr-Al based alloy, further containing at least one kind of element selected from Ti, Nb, Ta, Mo, W and Zr in the range of 0.01 to 6% and a surface hardened layer 2 formed at least on a part of the surface of the alloy member body 1 and having hardness of >=700 Hv by Vickers hardness. The surface hardened layer is a nitrided layer formed by subjecting the surface of the alloy member body l to nitriding treatment or a coated layer formed by reactive sputtering or ion plating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-hardness corrosion-resistant alloy member used in an environment where corrosive substances such as acids, alkalis and salts are present, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, raw materials such as powders and granules are compressed to produce pharmaceuticals, quasi-drugs, cosmetics, pesticides, feeds,
When molding a tablet for food or the like, a die having a through hole according to the tablet shape, and a through hole (a die hole) of the die.
A molding die in which a lower punch and an upper punch inserted into the inside are combined is used. In a tablet molding machine using such a molding die, first, a raw material such as powder is filled into a die into which a lower punch is inserted, and the raw material is compressed by an upper punch, whereby a desired tablet is formed. You.

As described in, for example, Japanese Patent Application Laid-Open No. H7-8540, iron-based alloys such as alloy tool steel (for example, SKS2 and SKD11) or Mo-based alloys are used in a molding die used for a tablet molding machine or the like. Conventionally, a cemented carbide mainly composed of a compound such as W or W has been used. But,
These conventional alloys for molding dies do not always provide satisfactory properties in terms of corrosion resistance and strength, and there is a problem that the life of the molding dies is greatly reduced depending on the properties of the raw materials.

[0004] For example, with the recent diversification of applications,
There is a need to press-mold a highly corrosive powder such as an acidic powder or an alkaline powder. When a molding die made of a conventional alloy tool steel or the like is used for molding such a highly corrosive powder, their surfaces are corroded at an early stage. Corrosion of the mold surface causes a reduction in the releasability of the raw material powder, and further causes a deterioration in strength.

[0005] Further, in order to improve the corrosion resistance of a mold made of alloy tool steel or the like, it has been attempted to coat the surface with chromium plating, but a sufficient effect has not been obtained by peeling off the plating layer. Although the chromium plating layer has a certain effect on improving the surface hardness, etc.,
Since the film itself is easily peeled off, it is not possible to sufficiently and stably obtain an effect of improving abrasion resistance. For these reasons, it is desired to improve the corrosion resistance and the abrasion resistance while maintaining the strength and hardness of the mold member.

On the other hand, applications requiring corrosion resistance include:
Not limited to a manufacturing apparatus such as a mold for corrosive powder described above, for example, a processing apparatus for chemicals, a processing apparatus for waste liquid and waste mud,
Examples include a combustion device and its peripheral parts. Corrosion-resistant steel such as stainless steel has heretofore been used for such applications mainly requiring corrosion resistance. However,
Corrosion-resistant steel such as stainless steel has insufficient strength and hardness, and cannot be used particularly for applications requiring hardness and abrasion resistance.

For example, Japanese Patent Application Laid-Open No. 63-18031 discloses that
As a hot press mold with excellent corrosion resistance, Cr 20-50 mass
%, 1.5 to 9% by mass of Al, and the balance being substantially Ni
The type is listed. This press mold has a temperature of 500-800
℃, press pressure 500 ~ 2000kg / cm ^TwoHot (50-200MPa)
It shows high hardness to the press and has buckling resistance
It has the following characteristics, and has corrosion resistance due to Ni and Cr.
Have gained. However, from this Ni-Cr-Al alloy,
Mold parts have excellent material hardness and corrosion resistance,
They do not have sufficient abrasion resistance, and may vary depending on operating conditions.
Wear on the sliding parts of the parts, shortening the life of the parts
There is a disadvantage that.

[0008]

As described above, the alloy tool steel which has been conventionally used as a pressure forming die member is not suitable for forming highly corrosive substances such as acids, alkalis and salts. In addition, there is a problem that the mold surface is corroded and the life of the mold is greatly reduced. On the other hand, stainless steel and the like have been conventionally used for applications requiring corrosion resistance, but because of insufficient strength and hardness, they are used especially for applications requiring hardness and abrasion resistance. Can not do.

On the other hand, Ni-Cr-Al alloys which have been used as constituent materials for hot press dies have excellent material hardness and corrosion resistance, but do not always have sufficient wear resistance. However, there is a problem that abrasion progresses on the sliding portion of the component depending on use conditions.

[0010] The present invention has been made to address such a problem, and while maintaining characteristics according to applications requiring high strength and high hardness, such as a pressure molding die, acid,
An object of the present invention is to provide a high-hardness corrosion-resistant alloy member exhibiting good corrosion resistance to alkalis, salts, and the like and further improving the wear resistance of a sliding portion, and a method of manufacturing the same.

[0011]

According to a first aspect of the present invention, there is provided a high-hardness corrosion-resistant alloy member having a Cr content of 25%.
At least one of an alloy member main body composed of a Ni-Cr-Al-based alloy containing 60 to 60% by mass and Al in a range of 0.01 to 10% by mass, and the balance substantially consisting of Ni; And a hardened surface layer having a Vickers hardness of 700 Hv or more.

[0012] The second high-hardness corrosion-resistant alloy member of the present invention comprises:
As described in claim 2, 25 to 60 mass% of Cr,
0.01 to 10% by mass, and 0.01 to 6% by mass of at least one element selected from Ti, Nb, Ta, Mo, W and Zr.
Ni-Cr consisting essentially of Ni
-An alloy member main body made of an Al-based alloy, and a surface hardened layer formed on at least a part of the surface of the alloy member main body and having a Vickers hardness of 700 Hv or more.

[0013] In the high hardness corrosion resistant alloy member of the present invention,
The surface hardened layer may be, for example, a surface nitrided layer formed by nitriding the surface of the alloy member main body as described in claim 3, or reactive sputtering or ion plating as described in claim 5. Is applied. Further, as described in claim 7, the thickness of the hardened surface layer is preferably in the range of 2 to 300 μm.

The alloy member of the present invention has high strength and high hardness and good corrosion resistance, and furthermore has excellent wear resistance. In other words, Ni with Cr having essentially good corrosion resistance is Cr
Ni-Cr-Al-based alloys with Al and Al added can further improve corrosion resistance, and the aging treatment causes the γ-phase, α-phase, γ'-phase, etc. to precipitate and become harder. Can be. On top of that, on the surface of the alloy member such as a sliding part, a surface hardened layer having a Vickers hardness of 700 Hv or more, which is composed of a surface nitrided layer or a coating layer formed by reactive sputtering or ion plating, is provided. Good abrasion resistance can be obtained. Therefore, it is possible to suppress a decrease in the life of the component due to wear of the sliding portion.

It is generally known that when the surface of a material is nitrided, the corrosion resistance is degraded due to the effect of the modified layer. In the case of (Cr-Al-based alloy), since it contains a large amount of Cr, even if nitriding, the corrosion resistance does not deteriorate. In addition, when coating is usually applied on a soft material, problems such as film peeling are likely to occur,
Ni-Cr-A used as an alloy member body in the present invention
Since the l-based alloy has high hardness, peeling of the coating layer and the like can be effectively suppressed.

The high-hardness corrosion-resistant alloy member of the present invention as described above is required to have corrosion resistance in addition to strength and hardness, and is suitably used for various applications in which a sliding operation is added. As a specific use application, for example, as described in claim 9, a member for a pressure molding die of a raw material containing a corrosive substance may be mentioned. However, the application of the high-hardness corrosion-resistant alloy member of the present invention is not limited to this. For example, the high-hardness corrosion-resistant alloy member is suitably used for peripheral sliding parts of chemical industrial equipment.

According to a first aspect of the present invention, there is provided a method for manufacturing a high hardness corrosion resistant alloy member, comprising the steps of:
Hot working the Al-based alloy to produce a Ni-Cr-Al-based alloy material; and subjecting the Ni-Cr-Al-based alloy material to a solution treatment at a temperature in the range of 900 to 1350 ° C. Thereafter, a rough processing step of processing to a shape similar to a desired member shape, and a step of performing aging treatment on the Ni-Cr-Al-based alloy material having passed through the rough processing step at a temperature in the range of 500 to 900 ° C, A finishing step of processing the Ni-Cr-Al-based alloy material subjected to the aging treatment to a desired member shape;
The surface of the Ni-Cr-Al-based alloy member having the member shape is subjected to nitriding treatment or coating treatment by reactive sputtering or ion plating, and the Ni
-Forming a surface hardened layer at a desired position on the surface of the Cr-Al-based alloy member.

According to a second aspect of the present invention, there is provided a method for manufacturing a high hardness corrosion resistant alloy member comprising the steps of:
Hot working the Al-based alloy to produce a Ni-Cr-Al-based alloy material; and subjecting the Ni-Cr-Al-based alloy material to a solution treatment at a temperature in the range of 900 to 1350 ° C. Thereafter, a rough processing step of processing to a shape similar to a desired member shape, and a finishing processing step of processing the Ni-Cr-Al-based alloy material having undergone the rough processing step to a desired member shape,
Ni-Cr-Al-based alloy member having the member shape,
Forming a nitrided layer as a surface hardened layer at a desired position on the surface of the Ni-Cr-Al-based alloy member while performing aging at a temperature in the range of 500 to 900 ° C. It is characterized by:

[0019]

Embodiments of the present invention will be described below.

FIG. 1 is a sectional view showing the structure of a main part of a high-hardness corrosion-resistant alloy member according to a first embodiment of the present invention. In the figure, reference numeral 1 denotes an alloy member main body made of a Ni-Cr-Al-based alloy. The surface of the alloy member main body 1 has JIS Z
A surface nitrided layer 2 having a hardness of 700 Hv or more in Vickers hardness specified in 2244-1992 is formed as a surface hardened layer, thereby forming a high hardness corrosion resistant alloy member 3.

First, the alloy member main body 1 will be described in detail.
The alloy member main body 1 of the high hardness corrosion resistant alloy member 3 of the present invention includes:
It is composed of a Ni-Cr-Al-based alloy containing 25 to 60% by mass of Cr and 0.01 to 10% by mass of Al and the balance substantially consisting of Ni. The Ni-Cr-Al-based alloy constituting the alloy member body 1 further includes Ti, Nb, T
At least one element selected from a, Mo, W and Zr may be contained in the range of 0.01 to 6% by mass.

The Ni-Cr-Al alloy contains a small amount of unavoidable impurities (Fe, V, Co, Cu, O, N, etc.).
May be contained, for example, in a range of about 0.1% by mass or less. In the production process, Si is 0.002% by mass as SiO _2.
Although it may be inevitable to some extent, it does not affect the properties of the alloy member of the present invention.

Ni—Cr—A constituting the alloy member main body 1
Preferably, the l-based alloy contains Ni as a main component. Ni as a main component enhances toughness and imparts corrosion resistance, and is a component that forms the γ phase (mother phase) of the Ni—Cr—Al alloy.

Cr has high corrosion resistance like Ni, and Ni-
It is a component that imparts excellent corrosion resistance to Cr-Al-based alloys and various components using the same. Cr is a component that promotes the precipitation of the α phase based on the grain boundary reaction by the aging treatment described later in detail. Ni-Cr-A containing an appropriate amount of Cr
In an l-based alloy, the aging treatment precipitates a Cr-based α phase, and improves the strength and hardness.

The content of such Cr is preferably in the range of 25 to 60% by mass. When the content of Cr is less than 25% by mass, the amount of the α phase precipitated by the aging treatment is insufficient, and sufficient strength and hardness may not be obtained. On the other hand, Cr
If the content exceeds 60% by mass, the ductility decreases and the material becomes brittle. The content of Cr is preferably in the range of 30 to 45% by mass, which allows the α phase to be more stably precipitated,
More preferably, it is in the range of 35 to 43% by mass.

Al further enhances the corrosion resistance of the Ni—Cr—Al alloy and thus various components using the same,
It is a component that contributes to improvement in strength and hardness when added in combination with Cr. That is, Al is subjected to, for example, an aging treatment described later in detail, for example, causing a γ ′ phase (Ni ₃
Al, etc.).

Al significantly enhances age hardening when added in a small amount, and its content is preferably in the range of 0.01 to 10% by mass. If the Al content is less than 0.01% by mass, the effect of improving hardness and strength by age hardening cannot be sufficiently obtained. On the other hand, if the Al content exceeds 10% by mass, the hardness after the solution treatment described below becomes too high, and the machinability and the like are reduced. The content of Al is 0.1 to 5% by mass, which makes it possible to obtain a composite precipitation structure more stably.
Is preferably in the range of 1.5 to 4.5% by mass.
It is desirable to be within the range.

By obtaining a composite precipitation structure (particularly a laminated structure) of the γ phase, α phase, and γ ′ phase as described above,
High hardness and high strength can be imparted to the i-Cr-Al-based alloy. Specifically, the hardness of the alloy member main body 1 (Ni-Cr-Al-based alloy) according to the present invention is determined after the aging treatment.
Vickers hardness specified in JIS Z 2244-1992 can be 500Hv or more. The hardness of the Ni-Cr-Al-based alloy can be set to Vickers hardness of 650 Hv or more by controlling the aging condition. Furthermore, the alloy member main body 1 according to the present invention has good corrosion resistance based on the basic components of Ni, Cr and Al.

Ni-Cr-A constituting the alloy member body 1
The l-based alloys include Ti, Nb,
At least one element selected from Ta, Mo, W and Zr may be contained in the range of 0.01 to 6% by mass.
In this case, various characteristics of the Ni-Cr-Al-based alloy can be improved based on each of these elements. That is,
Since each of the above-mentioned elements partially dissolves in the α phase and the γ phase and partially precipitates as dispersed particles such as carbides, the effects of solid solution strengthening and dispersion strengthening can be stably obtained. More preferably, the content of these elements is in the range of 0.5 to 4% by mass.

Further, the Ni—Cr—Al alloy is S
At least one element selected from i, C, Mg, Mn, Ti and B may be contained, for example, in a range of 0.005 to 0.8% by mass. Mn, Si, C, Mg and the like function as deoxidizing agents. The content of the deoxidizing agent is preferably set to 0.1% by mass or less. Further, Mg, Ti, B and the like function as a ductility improving component, and the content thereof is preferably 0.1% by mass or less. In order to sufficiently obtain these functions, the content of each additive element is preferably 0.005% by mass or more.

The surface of the alloy member body 1 made of the Ni-Cr-Al-based alloy as described above has a Vickers hardness of 70%.
The surface nitrided layer 2 having a hardness of 0 Hv or more is formed as a surface hardened layer. Here, the surface hardened layer does not have to be formed on the entire surface of the alloy member main body 1,
It can be formed only on the surface where abrasion resistance is required depending on the use application. Further, as a matter of course, the surface hardened layer may be formed on the entire surface of the alloy member main body 1.

The surface nitrided layer 2 is formed by subjecting the surface of the alloy member main body 1 to a nitriding treatment, and is mainly composed of, for example, chromium nitride. Ni-
When the surface of the alloy member main body 1 made of a Cr-Al alloy is subjected to a nitriding treatment, chromium nitride (CrN) which is easily nitrided
Is formed mainly. Such a surface nitrided layer 2 has a high hardness, a Vickers hardness of 700 Hv or more,
Furthermore, it shows a hardness of 1000 to 3000 Hv.

The surface nitrided layer 2 is formed on the alloy member body 1
It is possible to greatly improve the wear resistance of the high hardness corrosion-resistant alloy member 3 by forming it on the surface. Specifically, when a sliding test or the like is performed under a high pressure and corrosive environment, it is possible to suppress wear of the sliding portion for a long period of time. That is, excellent wear resistance is obtained. Since the surface nitrided layer 2 is also excellent in corrosion resistance, it is particularly effective for improving wear resistance in a corrosive environment.

Further, since the surface nitrided layer 2 is formed by nitriding the constituent elements of the alloy member main body 1, the surface nitrided layer 2 exhibits excellent adhesion to the alloy member main body 1. Therefore, even when used under sliding conditions, the surface nitrided layer 2 does not peel off and the effect is not impaired. That is, the effect of improving the wear resistance by the surface nitrided layer 2 can be stably obtained over a long period of time.

In order to obtain the effect of improving the wear resistance as described above, the surface nitrided layer 2 needs to have a Vickers hardness of 700 Hv or more. The Vickers hardness of the surface nitrided layer 2 as the surface hardened layer is more preferably 1000 Hv or more.

The thickness of the surface hardened layer composed of the surface nitrided layer 2 is preferably in the range of 2 to 300 μm. If the thickness of the surface nitrided layer 2 is less than 2 μm, the surface hardness may not be sufficiently increased. Although the hardness of the surface nitrided layer 2 increases as the thickness increases, even if the thickness of the surface nitrided layer 2 exceeds 300 μm, not only no further effect can be obtained, but also a rise in manufacturing costs and There is a risk of peeling. More preferably, the thickness of the surface nitrided layer 2 is in the range of 3 to 100 μm.

The nitriding treatment for forming the surface nitrided layer 2 may be performed by, for example, heat treating the alloy member body 1 at a temperature of 350 to 700 ° C. in a nitrogen gas or a compound atmosphere containing nitrogen such as ammonia. An ion nitriding method by glow discharge in a vacuum atmosphere or a reduced-pressure atmosphere can be applied. Among them, particularly according to the ion nitriding method, the surface compound layer (surface nitride layer 2) after the treatment has no pores and can be a dense layer, so that a better surface hardened layer can be obtained. Also, because partial nitriding is easy,
A cured layer can be formed only on the surface where abrasion resistance is required according to the intended use.

According to the high-hardness corrosion-resistant alloy member 3 having the surface nitrided layer 2 as described above, in addition to the strength, hardness and corrosion resistance of the alloy member main body 1,
Good wear resistance can be obtained by the surface nitrided layer 2. Therefore, even when the high hardness corrosion-resistant alloy member 3 is used in an environment (condition) in which a corrosive substance is present and a high pressure is applied, a sliding operation is further applied. Corrosion and abrasion of the sliding portion as a whole can be favorably suppressed. Thus, it is possible to achieve a longer life and the like of various components formed of the high hardness corrosion resistant alloy member 3.

Next, a high hardness corrosion resistant alloy member according to a second embodiment of the present invention will be described with reference to FIG.
The high-hardness corrosion-resistant alloy member 3 shown in FIG. 2 has the same alloy member body 1 as that of the first embodiment described above, that is, Ni—Cr.
A coating layer 4 having a Vickers hardness of 700 Hv or more on the surface of the alloy member body 1 made of an Al-based alloy;
Is formed.

The coating layer 4 as a surface hardened layer is
It is formed by reactive sputtering or ion plating. The coating layer 4 formed by these reactive sputtering or ion plating is made of titanium nitride (TiN), titanium carbonitride (TiCN), titanium carbide (TiC), zirconium nitride (ZrN), chromium nitride (CrN), and titanium aluminum nitride. It is preferable to mainly constitute at least one kind selected from (TiAlN).

By forming such a nitride layer, carbide layer, carbonitride layer, etc. by reactive sputtering or ion plating, the Vickers hardness is 700 Hv or more, and more preferably 1000 to The coating layer 4 having high hardness such as 3000 Hv and exhibiting excellent adhesion to the alloy member main body 1 can be obtained. Therefore, the wear resistance of the high-hardness corrosion-resistant alloy member 3 can be significantly improved, and such an effect can be stably obtained over a long period of time.

In order to obtain the effect of improving the wear resistance as described above, the coating layer 4 needs to have a hardness of 700 Hv or more in Vickers hardness. The Vickers hardness of the coating layer 4 as the surface hardened layer is more preferably 1000 Hv or more. The thickness of the surface hardened layer composed of the coating layer 4 is 2 for the same reason as the surface nitrided layer 2.
The thickness is preferably in a range of from 300 to 300 µm, and more preferably in a range of from 3 to 100 µm.

According to the high hardness corrosion-resistant alloy member 3 having the coating layer 4, in addition to the strength, hardness and corrosion resistance of the alloy member main body 1,
Good abrasion resistance can be obtained by the coating layer 4. Further, since the coating layer 4 exhibits excellent adhesion to the alloy member main body 1, it is possible to stably obtain excellent wear resistance of the coating layer 4 over a long period of time.

Therefore, when the high hardness corrosion-resistant alloy member 3 is used for an application in which a sliding operation is further applied in an environment (condition) where a corrosive substance is present and a high pressure is applied. Also, it is possible to favorably suppress corrosion of the entire member and wear of the sliding portion. By these,
It is possible to achieve a long life and the like of various components constituted by the high hardness corrosion resistant alloy member 3.

The high-hardness corrosion-resistant alloy member 3 of the present invention as described above is suitable as, for example, a punch or a die used for making various raw materials into tablets, that is, as a constituent material of a press-molding die. In other words, the high-hardness corrosion-resistant alloy member 3 of the present invention satisfies the strength and hardness required for the pressure molding die, has good corrosion resistance, and further has excellent wear resistance. is there.

Therefore, even when the present invention is applied to pressure molding of a raw material containing a corrosive substance such as an acidic powder, the progress of corrosion of the pressure molding die can be greatly suppressed, and
Wear of the sliding portion can be suppressed. Thus, it is possible to achieve a longer life of the pressing mold and an improvement in reliability.

Further, the high hardness corrosion resistant alloy member 3 of the present invention
The Ni-Cr-Al-based alloy (alloy member main body 1) used in Example 1 exhibits good machinability by solution treatment. By performing the processing and the finishing processing, it is possible to suppress an increase in processing cost.
Therefore, it is possible to reduce the cost and the accuracy of the pressure mold having high hardness, high strength, and high corrosion resistance.

The use of the high-hardness corrosion-resistant alloy member 3 of the present invention is not limited to the above-mentioned members for press-molding dies, and is preferably used for, for example, peripheral sliding parts of chemical industrial equipment. It is.

The high-hardness corrosion-resistant alloy member 3 according to the first and second embodiments is manufactured, for example, as follows.

That is, first, Ni having the above-described composition
After melting and casting the Cr-Al-based alloy to form an ingot, hot forging or rolling is performed to produce a Ni-Cr-Al-based alloy material having an appropriate size and shape. Melting, casting, forging, rolling and the like are performed according to a conventional method.

Next, the above-mentioned Ni-Cr-Al alloy material is subjected to a solution treatment. Heating temperature during solution treatment is 900
The temperature is preferably in the range of 1350 ° C. Heating temperature is 900
If the temperature is lower than 0 ° C., the solution-hardened region cannot be reached, and good cutting workability or the like may not be obtained.
On the other hand, if the heating temperature exceeds 1350 ° C., the temperature becomes just below the melting point, and there is a risk of causing partial melting and deformation. The holding time at the above temperature (solution treatment time) is not particularly limited, but is preferably 1 hour or more. The rapid cooling from the above temperature is performed by, for example, oil cooling or water cooling.

The solution-treated Ni-Cr-Al-based alloy material is then roughly processed to a shape similar to a desired member shape, specifically, a shape slightly larger than the desired member shape. The processed shape at this time is a shape that is at least 0.2% or more larger than the desired member size, and preferably a shape that is larger by about 1%. At this point, the Ni-Cr-Al-based alloy material has good cutting workability by solution treatment, that is, appropriate hardness, and thus does not cause a decrease in workability or the like. In other words, it can be processed at low cost.

Ni-Cr-Al roughened as described above
The processing steps for the base alloy material (working material) are as follows:
You can choose one of two ways.

First, in the first method, an aging treatment is applied to the roughly machined Ni-Cr-Al alloy material. The heating temperature at the time of the aging treatment is preferably in the range of 500 to 900 ° C. After maintaining at such a temperature for 2 to 6 hours, the temperature is gradually cooled to room temperature. If the heating temperature of the aging treatment is lower than 500 ° C., the precipitation amount of the α phase and γ ′ phase described above becomes insufficient, and Ni—Cr—A
There is a possibility that the l-based alloy material cannot be sufficiently age-hardened. On the other hand, if the heating temperature exceeds 900 ° C., the temperature becomes close to the solid solution region, the precipitation amount of the α phase and the γ ′ phase decreases, and the hardness may decrease. The aging temperature is more preferably in the range of 550 to 700 ° C.

By the aging treatment described above, Ni-
The hardness of the Cr-Al-based alloy material (alloy member main body) is, for example, Vickers hardness of 500 Hv or more, and further, 650 Hv or more. After finishing the aging-treated Ni-Cr-Al-based alloy material to a predetermined member size, this Ni-Cr
-The hardened corrosion-resistant alloy member 3 of the present invention is formed by subjecting a desired surface of the Al-based alloy member to nitriding treatment to form the surface nitrided layer 2 or forming the coating layer 4 by reactive sputtering or ion plating. Is obtained. Specific conditions of the surface nitrided layer 2 and the coating layer 4 are as follows:
As described above.

Further, in the second method, the aging treatment is performed after finishing the rough-worked Ni—Cr—Al-based alloy material to a predetermined member size. At this time, the aging treatment temperature is in the range of 500 to 900 ° C. as described above, but this temperature substantially overlaps with the nitriding treatment temperature described above. Therefore, the aging treatment is performed in, for example, a nitrogen gas or an ammonia gas (gas nitriding), so that the finished Ni—Cr
A nitriding treatment can be performed on the surface of the Al-based alloy material while age-hardening it. At this time, it is also possible to apply ion nitriding. That is, it is possible to form the surface nitrided layer 2 as a hardened layer on the surface while increasing the hardness of the Ni—Cr—Al-based alloy material. Even by such a method, the high hardness corrosion resistant alloy member 3 of the present invention can be obtained.

The above-mentioned high hardness corrosion resistant alloy member 3 of the present invention
In the production method described above, when the surface nitrided layer 2 and the coating layer 4 are formed after the aging treatment and the finishing, the accuracy of the member shape can be improved. On the other hand, when the aging treatment and the nitriding treatment are performed simultaneously, the manufacturing cost can be reduced. In either method,
It is possible to obtain the high hardness corrosion resistant alloy member 3 of the present invention with good reproducibility.

[0058]

Next, specific examples of the present invention and evaluation results thereof will be described.

Example 1 First, a Ni—Cr—Al alloy containing 38.0% by mass of Cr and 3.8% by mass of Al and the balance substantially consisting of Ni was used.
After melting and casting the system alloy sample, it was hot forged and hot rolled into a 35 mm diameter round bar. This Ni-Cr-A
The l-based alloy material was kept at 1200 ° C. for 2 hours, then cooled with oil and solution-treated. After the Ni-Cr-Al-based alloy material after the solution treatment was cut, it was aged by holding it at a temperature of 650 ° C for 5 hours. The Vickers hardness of the alloy material after the aging treatment was 660 Hv.

Next, the Ni-Cr-
After finishing the Al-based alloy material, 60
Nitriding heat treatment was performed at 0 ° C. × 2 hours to form a nitrided layer on the surface of the Ni—Cr—Al alloy member. The state of the obtained nitrided layer was measured and evaluated.
rN and its thickness is about 4.5μm
And the Vickers hardness of the surface was 1050 Hv. The high-hardness corrosion-resistant alloy member having such a surface nitrided layer was subjected to characteristic evaluation described later.

Example 2 A Ni-Cr-Al alloy sample having the same composition as in Example 1 was melted and cast, and then hot forged and hot rolled into a round bar having a diameter of 35 mm. This Ni—Cr—Al alloy material was kept at 1200 ° C. for 2 hours and then oil-cooled to perform a solution treatment. After cutting and finishing the Ni-Cr-Al-based alloy material after solution treatment, 650 ° C in a nitrogen atmosphere
Heat treatment was performed for 5 hours. By this heat treatment, N
A nitride layer was formed on the surface of the i-Cr-Al alloy material while age hardening the material.

The Vickers hardness of the Ni-Cr-Al-based alloy member main body after the aging treatment was 665 Hv. The Vickers hardness of the member body was determined by measuring the hardness of the cut surface. The obtained nitrided layer is mainly composed of CrN, and has a thickness of about 5.
At 0 μm, the Vickers hardness of the surface was 1060 Hv. The high-hardness corrosion-resistant alloy member having such a surface nitrided layer was subjected to characteristic evaluation described later.

Example 3 A Ni-Cr-Al alloy sample having the same composition as in Example 1 was melted and cast, and then hot forged and hot rolled to obtain a round bar having a diameter of 35 mm. This Ni—Cr—Al alloy material was kept at 1200 ° C. for 2 hours and then oil-cooled to perform a solution treatment. After the Ni-Cr-Al-based alloy material after the solution treatment was cut, it was aged by holding it at a temperature of 650 ° C for 5 hours. Vickers hardness of alloy material after aging treatment is 660H
was v.

Next, the Ni-Cr-
After finishing the Al-based alloy, 65
Ion nitriding was performed at a temperature of 0 ° C. to form a nitrided layer on the surface of the Ni—Cr—Al-based alloy member. The obtained ion nitrided layer was mainly composed of CrN, had a thickness of about 8.0 μm, and had a Vickers hardness of 1050 Hv on the surface.
The high-hardness corrosion-resistant alloy member having such a surface nitrided layer was subjected to characteristic evaluation described later.

Comparative Example 1 A Ni—Cr—Al alloy sample having the same composition as in Example 1 was melted and cast, and then hot forged and hot rolled into a round bar having a diameter of 35 mm. This Ni—Cr—Al alloy material was kept at 1200 ° C. for 2 hours and then oil-cooled to perform a solution treatment. After the Ni-Cr-Al-based alloy material after the solution treatment was cut, it was aged by holding it at a temperature of 650 ° C for 5 hours. After finishing this alloy member, it was subjected to the following property evaluation.

The surface hardness of each of the high hardness corrosion resistant alloy members according to Examples 1 to 3 and Comparative Example 1 was measured using a Vickers tester under the conditions of 1000 g and a load of 15 seconds. Further, the wear amount of each alloy member (the wear amount of the portion having the surface nitrided layer in Examples 1 to 3) was measured using a Nishihara-type metal abrasion tester (compression load: 2940N (300 kgf), rotation rate: 800 rpm, test piece). Dimensions: diameter 30mm x 8mm, mating material: tool steel of hardness 870Hv)
Was used to measure the amount of wear after rotation at 5 × 10 ⁵ times. Furthermore, the corrosion resistance of each alloy member was measured by standing for 72 hours in a solution of salt water (concentration = 5%) and sulfuric acid (concentration = 5%) for 72 hours, and then visually observing the presence or absence of corrosion. Was evaluated. The results are shown in Table 1.

[0067]

[Table 1] As is clear from Table 1, each of the high hardness corrosion resistant alloy members according to Examples 1 to 3 has not only excellent corrosion resistance, but also high surface hardness, and as a result, excellent wear resistance.

Examples 4 to 9 Using alloy samples each having the composition shown in Table 2, each Ni-C
The r-Al-based alloy material was subjected to aging treatment and finishing in the same manner as in Example 3. Each of these Ni-Cr-
The Al-based alloy member was ion-nitrided to form a nitrided layer on each surface. In this ion nitriding step, the thickness of the nitrided layer was adjusted as shown in Table 2 by adjusting the conditions of the temperature and time of the nitriding treatment.

The surface hardness and the amount of wear of each of the high hardness corrosion resistant alloy members according to Examples 4 to 9 thus obtained were measured and evaluated in the same manner as in Example 1. These values are also shown in Table 2.

[0070]

[Table 2] Examples 10 to 17 Using alloy samples each having a composition shown in Table 3, each Ni-C
The r-Al-based alloy material was subjected to aging treatment and finishing in the same manner as in Example 3. Each of these Ni-Cr-
A coating layer was formed on the surface of the Al-based alloy member by reactive sputtering or ion plating. The material and thickness of the coating layer are as shown in Table 3.

At this time, the reactive sputtering is performed under the following sputtering pressure:
4 × 10 ^-1 Pa, sputter current: 5A, Ar flow rate: 15sccm, N
The flow rate was set at 30 sccm, and the film thickness was adjusted by the gas pressure. In addition, ion plating has a power input of 5k
The operation was performed under the condition of W, and the film thickness was further adjusted.

The surface hardness and the amount of wear of each of the high hardness corrosion resistant alloy members according to Examples 10 to 17 thus obtained were
Measurement and evaluation were performed in the same manner as in Example 1. These values are also shown in Table 3.

[0073]

[Table 3] FIG. 3 shows an ion nitride layer as a surface hardened layer, TiN
Coating layer (formed by ion plating),
3 shows the relationship between each film thickness of the CrN coating layer (formed by ion plating) and the surface hardness (Hv). From this figure, it can be seen that the required surface hardness can be obtained by setting the film thickness of the surface hardened layer to 2 μm or more. Further, since the rate of improvement of the surface hardness becomes slower when the thickness exceeds 10 μm, no further effect can be obtained even if the thickness is too large. In consideration of corrosion resistance and the like, the thickness of the surface hardened layer is preferably 300 μm or less.

[0074]

As described above, according to the present invention, a high-hardness corrosion-resistant alloy member having both sufficient strength and good corrosion resistance and exhibiting excellent wear resistance can be provided. Such a high-hardness corrosion-resistant alloy member has a long component life even in an application in which, for example, a corrosive substance is present and a sliding operation is applied under an environment (condition) where a high pressure or the like is applied. It is possible to greatly improve.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a main part of a high hardness corrosion resistant alloy member according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a configuration of a main part of a high hardness corrosion resistant alloy member according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a relationship between a surface hardened layer and a surface hardness in the high hardness corrosion resistant alloy member of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Alloy member main body 2 ... Surface nitride layer 3 ... High hardness corrosion resistant alloy member 4 ... Coating layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // C22C 27/06 C22C 27/06 C22F 1/00 602 C22F 1/00 602 613 613 630 630 630C 631 631B 640 640A 682 682 683 683 691 691B 1/11 1/11 (72) Inventor Hitoshi Nakajima 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture F-term in Toshiba Yokohama Office 4K028 AA02 AB02 AC08 BA02 BA13 4K029 AA02 BA54 BA55 BA58 BA60 BC00 BC01 BD05 CA04 CA06 EA01

Claims (13)

[Claims] 1. A Ni— alloy containing 25 to 60% by mass of Cr and 0.01 to 10% by mass of Al, with the balance substantially consisting of Ni.
An alloy member main body made of a Cr-Al-based alloy, formed on at least a part of a surface of the alloy member main body,
A high hardness corrosion resistant alloy member comprising: a surface hardened layer having a Vickers hardness of 700 Hv or more. 2. An alloy containing 25 to 60% by mass of Cr, 0.01 to 10% by mass of Al, and at least one element selected from Ti, Nb, Ta, Mo, W and Zr in a range of 0.01 to 6% by mass. An alloy member main body made of a Ni-Cr-Al-based alloy substantially composed of Ni, and formed on at least a part of the surface of the alloy member main body;
A high hardness corrosion resistant alloy member comprising: a surface hardened layer having a Vickers hardness of 700 Hv or more. 3. The high hardness corrosion resistant alloy member according to claim 1, wherein the hardened surface layer is a nitrided layer formed by nitriding a surface of the alloy member body. High hardness corrosion resistant alloy member. 4. The high-hardness corrosion-resistant alloy member according to claim 3, wherein the nitride layer is mainly made of chromium nitride. 5. The high hardness corrosion resistant alloy member according to claim 1, wherein the hardened surface layer is a coating layer formed by reactive sputtering or ion plating. Alloy members. 6. The high hardness corrosion resistant alloy member according to claim 5, wherein the coating layer is made of at least one selected from titanium nitride, titanium carbonitride, titanium carbide, zirconium nitride, chromium nitride, and titanium nitride / aluminum. A high-hardness corrosion-resistant alloy member mainly constituted. 7. The high hardness corrosion resistant alloy according to claim 1, wherein said hardened surface layer has a thickness in a range of 2 to 300 μm. Element. 8. The high hardness corrosion resistant alloy member according to claim 1, wherein said alloy member main body further comprises Si, C, Mg, Mn, and T.
0.005 to at least one element selected from i and B
A high-hardness corrosion-resistant alloy member characterized by being contained in the range of 0.8% by mass. 9. The high-hardness corrosion-resistant alloy member according to claim 1, wherein the high-hardness corrosion-resistant alloy member is used as a member for a pressure forming die of a raw material containing a corrosive substance. Corrosion resistant alloy members. 10. A step of subjecting a Ni-Cr-Al-based alloy to hot working to produce a Ni-Cr-Al-based alloy material, and applying a temperature of 900 to 1350 ° C to the Ni-Cr-Al-based alloy material. After performing a solution treatment at a temperature of about 5%, a rough working step of working to a shape approximate to a desired member shape, and a Ni-Cr-Al-based alloy material having passed through the rough working step, in a range of 500 to 900 ° C Aging treatment at a temperature, a finishing processing step of processing the Ni-Cr-Al-based alloy material subjected to the aging treatment to a desired member shape, and a Ni-Cr-Al-based alloy having the member shape The surface of the member is subjected to nitriding treatment or coating treatment by reactive sputtering or ion plating, and the Ni
Forming a surface hardened layer at a desired position on the surface of the Cr-Al-based alloy member. 11. A step of subjecting a Ni-Cr-Al-based alloy to hot working to produce a Ni-Cr-Al-based alloy material, and applying a temperature of 900 to 1350 ° C to the Ni-Cr-Al-based alloy material. After performing a solution treatment at a temperature of the above, a rough processing step of processing to a shape approximate to a desired member shape, and processing the Ni-Cr-Al-based alloy material having passed through the rough processing step to a desired member shape. Finishing processing step, Ni-Cr-Al-based alloy member having the member shape,
Forming a nitrided layer as a surface hardened layer at a desired position on the surface of the Ni-Cr-Al-based alloy member while performing aging at a temperature in the range of 500 to 900 ° C. A method for producing a high-hardness corrosion-resistant alloy member. 12. The method for producing a high-hardness corrosion-resistant alloy member according to claim 10, wherein the Ni—Cr—Al-based alloy contains 25 to 60% by mass of Cr;
Al in the range of 0.01 to 10% by mass, with the balance being substantially N
i. A method for producing a high-hardness corrosion-resistant alloy member, comprising: 13. The method for producing a high-hardness corrosion-resistant alloy member according to claim 10, wherein the Ni—Cr—Al-based alloy contains 25 to 60% by mass of Cr,
Al is contained in an amount of 0.01 to 10% by mass, at least one element selected from Ti, Nb, Ta, Mo, W and Zr in a range of 0.01 to 6% by mass, and the balance substantially consists of Ni. Of manufacturing a high hardness corrosion resistant alloy member.