JPH08134570A - Composite material having high corrosion resistance and wear resistance - Google Patents

Abstract

PURPOSE: To produce a resin finishing machine member for compound, excellent in corrosion resistance and wear resistance, by specifying the composition of a composite material in which hard layers composed essentially of carbides and borides are dispersed in an Ni-base matrix. CONSTITUTION: This composite material has a composition consisting of, by weight ratio, 2-6% B, 21-38% Cr, 8-22% Mo, 0.5-12% W, 3-6% Fe, 0.4-3% C, 0-2% Cu, 2-20% Ti or/and 1-5% Ta, and the balance Ni with inevitable impurities. It is preferable to further incorporate <=3% N into the composition. Moreover, the total content of W, Ti, and Ta in the hard layers is regulated to 6-25%. Further, it is desirable that the resin finishing machine member is produced by adding a binder to a powder of prescribed amounts of Ni-base alloy, Cu, TiC, TiN, CrB, WC, and TaC to form pelletized powder of 250-500μm, compacting and sintering it, and then finishing the resultant sintered compact into the shape of the member.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high corrosion resistance and wear resistance composite material in which a hard phase mainly composed of carbides and borides having a high corrosion resistance and a high wear resistance, and optionally a nitride is bonded by a Ni-based matrix. Is. For example, it is suitable for cylinder materials and screw materials for resin processing machines that target highly corrosive plastics and plastics such as rubber. In particular, corrosion resistance to hydrochloric acid and hydrofluoric acid is required, and abrasion resistance is also required. It is suitable as a corrosion resistant and abrasion resistant material for resin processing machines for compounds that require high properties.

[0002]

2. Description of the Related Art Cylinders and screw materials of an extruder or an injection machine in a resin processing machine are liable to be worn by an object to be processed or contact wear between metals, and are therefore made of materials having excellent wear resistance. There is a need. For this reason, conventionally, the above materials have been used in addition to the self-fluxing wear-resistant Ni-based alloys and N having excellent wear resistance.
A composite material in which hard particles such as WC are added to an i-based self-fluxing alloy is used.

[0003]

By the way, due to the recent enhancement of the functionality of molding materials, the environment in which a resin processing machine is used has become more severe. For example, in molding processing under high temperature conditions, resin processing The machine is exposed to the corrosive gases generated by the resin and is susceptible to corrosion. Therefore, even with conventional materials for resin processing machines,
It is not possible to focus only on wear resistance, and excellent characteristics are also required for corrosion resistance. However, although the self-fluxing wear-resistant Ni-based alloy and the WC-added composite material described above have good wear resistance, they do not have sufficient corrosion resistance. On the other hand, a Ni-Cr-Mo alloy is known as a material having excellent corrosion resistance, and in fact, there is an example of use in a resin processing machine.
However, this material does not have sufficient abrasion resistance, and has a drawback that, for example, adhesion or galling due to contact between members is likely to occur. As described above, in the conventional materials, the material excellent in corrosion resistance does not have sufficient wear resistance, and the material excellent in wear resistance has insufficient corrosion resistance. For this reason, recently, development of materials having excellent properties in both wear resistance and corrosion resistance has been advanced, but realization of a material sufficiently combining both excellent properties has not been achieved. The present invention has been made in view of the above circumstances, and an object thereof is to provide a highly corrosion-resistant and abrasion-resistant composite material that can withstand use in a highly corrosive environment in a resin processing machine under severe conditions of use. And

[0004]

In order to solve the above problems, the inventors of the present invention have a hard phase mainly composed of Mo-Cr-Ni-based borides and carbides and nitrides such as WC, TiC, TiN and TaC. Attention was paid to a hard alloy in which is dispersed. Furthermore, the present inventors have found that, in the process of developing a wear resistant material having corrosion resistance, this boride has not only high hardness but also excellent corrosion resistance, and the above boride, WC, TiC A composite material of the present invention having excellent corrosion resistance and wear resistance is obtained by combining a carbide or a nitride such as TiN, TiN or TaC, or a Ni-based alloy.

That is, the high corrosion-resisting and abrasion-resistant composite material of the first invention of the present invention is a composite material in which a hard phase mainly composed of carbide and boride is bonded by a Ni-based matrix, and the matrix and The total amount of the hard layer is B: 2 to 6% by weight, Cr: 21 to 38% by weight, Mo: 8
-22% by weight, W: 0.5-12% by weight, Fe: 3-6
%, C: 0.4 to 3% by weight, Cu: 0 to 2% by weight, Ti: 2 to 20% by weight, Ta: 1 to 5% by weight, and 1 or 2 types thereof, The balance consists of Ni and inevitable impurities. The second invention is N
A composite material in which a hard layer mainly composed of carbide, boride and nitride is dispersed in an i-based matrix, wherein the matrix and the hard layer are B: 2 to 6% by weight in total,
Cr: 21-38% by weight, Mo: 8-22% by weight, W:
0.5 to 12% by weight, Fe: 3 to 6% by weight, C: 0.4
˜3% by weight, N: 3% by weight or less, Cu: 0 to 2% by weight, further Ti: 2 to 20% by weight, Ta: 1 to 5
It is characterized by containing 1% or 2% by weight and the balance being Ni and inevitable impurities. The third invention is
1st or 2nd invention WHEREIN: W, Ti, T in a hard layer
The total content of a is 6 to 25%.

In the above hard phase, carbides, nitrides, borides as the added alloy, or carbides, nitrides, borides reacted with the contained components are the main components, and most of the borides are compound borides. Become. Further, in carbides and nitrides, compound carbides and nitrides may be produced. The composition of the present invention is preferably provided as a powder and manufactured by a powder metallurgy method of sintering the powder. According to this method, a composite material in which hard materials are uniformly dispersed can be obtained. Further, by using the HIP method, a composite material having higher strength and higher toughness can be obtained.

In the above powder metallurgy, all or part of W, Ti and Ta is provided as a carbide powder such as WC, and C
All or part of r, Mo, and B can be provided as CrB and MoB powders, and nitrides such as Ti can be provided as powders. These are, for example, WC: 5 to 15% by weight, TiC: 3 to 15% by weight, TaC: 0 to 5% by weight, CrB: 0 to 24.5% by weight, MoB: 0 to 24.
5% by weight, TiN: 0 to 13% by weight. When these powders are used, as the master alloy powder, those having a composition as required within the scope of the invention are used. For example, Cr: 15 to 16% by weight, Mo: 15 to 15
A master alloy of 17% by weight, W: 3 to 4% by weight and the balance substantially consisting of Ni is used.

The above master alloy powder is preferably manufactured by the atomizing method for the sake of sinterability and uniformity of structure. The carbide powder, the nitride powder, the boride powder, and the master alloy powder are mixed in a predetermined amount by a ball mill or the like, and the mixed powder is molded and then sintered. For example, when liquid phase sintering is performed, the sintering is performed at 1000 to 1300 ° C. for 10 to 120 minutes. The sintering method is not limited to this,
Besides the normal sintering method, it is also possible to adopt other sintering methods such as hot isostatic pressing (HIP) and hot pressing. In addition, when the sintering temperature is raised and, for example, sintering is performed at 1100 ° C. or higher, CrB reacts with other components to form a compound boride. In addition, thermodynamically stable TiC or the like does not react and disperses alone in the tissue. In addition, there are partially reactive carbides such as WC, which exhibit their respective characteristics. As described above, the present invention is suitable for a cylinder material, a screw material, and the like of a resin processing machine and an extrusion molding machine or an injection molding machine of ceramics, metal, etc., but is not limited to these applications. In addition, it can be used as a material for other applications requiring corrosion resistance and abrasion resistance.

[0009]

That is, according to the composite material of the present invention, as a result of various experiments, during sliding, the boride composed of Cr, Mo, W, etc. (mainly the composite boride) plays the role of the lubricant, and Mitigates aggression against. In addition, the composite boride exhibits appropriate wear resistance and improves corrosion resistance. Furthermore, by combining a compound boride with a carbide composed of W, Ti, Ta, etc., or a nitride such as TiN, the adhesion wear between metals is reduced, and the carbide or nitride with high hardness itself It also effectively works against abrasive wear due to its wear resistance. Therefore, according to the present invention, a material having both excellent corrosion resistance and abrasion resistance can be obtained. Next, the action of the components of the present invention and the reasons for limiting the content (% by weight) will be described.

B forms a M ₃ B ₂ type complex boride (a surface analysis by an electron beam microanalyzer (EPMA) and a result confirmed by an examination by X-ray diffraction) which becomes a hard phase by reacting with Cr, Mo, etc. It is an indispensable element in order to do.
However, if the B content is less than 2% by weight, the wear resistance becomes poor, while if it exceeds 6% by weight, the amount of the hard phase becomes excessive and the strength decreases, so the content is 2 to 6% by weight.
And For the same reason, it is desirable that the amount is 2 to 4% by weight.

[0011] Cr not only forms a carbide by reacting during sintering or forms a hard phase as a boride, but also forms a solid solution in the binder phase, so that it has corrosion resistance, wear resistance, heat resistance, and oxidation resistance. It has a function to improve sex. Mainly supplied as a boride or contained as a base alloy component. If the content is less than 21% by weight, the corrosion resistance is insufficient, and if it exceeds 38% by weight, the improvement in the corrosion resistance commensurate with the content is not recognized, and the toughness is also lowered, so that it is 21 to 3%.
It should be limited to 8% by weight. For the same reason, 2
It is desirable that the amount is 2 to 28% by weight.

[0012] Mo reacts with B to form a complex boride and has an action of increasing the corrosion resistance to a reducing atmosphere such as hydrofluoric acid. However, in order to secure sufficient corrosion resistance, the content of 8% by weight or more is necessary. But,
If it exceeds 22% by weight, a brittle intermetallic compound is formed,
Since it causes a decrease in wear resistance, it is limited to 8 to 22% by weight. For the same reason, it is desirable to set the content to 10 to 20% by weight.

W is a component that forms a hard phase to be dispersed in a Ni-based alloy and imparts heat resistance. Since W forms a complex carbide or complex boride by reacting with other components, it is supplied as a carbide. It is contained as an alloy component of the base material. If the content is less than 0.5% by weight, the wear resistance is insufficiently imparted, and if it exceeds 12% by weight, the material strength decreases and the specific gravity of the alloy increases, leading to higher weight. , 0.5-1 because it is disadvantageous in the structure of the member
The range is 2% by weight.

Ti and Ta constitute a hard phase to be dispersed in a Ni-based alloy like W, and W reacts with other components to form a composite carbide or a boride.
Improves wear resistance, but Ti and Ta, when supplied in the state of carbides, do not react much with other components and remain as hard carbides, improving wear resistance, especially abrasive wear resistance. . To ensure these effects, T
It is desirable that i and Ta be supplied in the form of carbides as raw materials, and part of Ti can also be supplied as nitrides. However, if the content of Ti or Ta is less than the lower limit, the above-mentioned action cannot be sufficiently obtained, while if it exceeds the upper limit, the material strength is deteriorated, so Ti: 2 to 20 wt%, Ta: 1 Up to 5% by weight. By incorporating Ti and Ta in combination with W described above, both the wear resistance and the abrasive wear resistance can be improved. However, if the total content of these components is less than 6% by weight, the abrasion resistance is insufficiently imparted, and
If the weight percentage is exceeded, the strength of the material will deteriorate, so a total of 6
It is desirable to limit it to -25% by weight. For the same reason, it is desirable to further limit the content to 8 to 20% by weight,
It is more desirable to limit the amount to 10 to 15% by weight.

C and N constitute a hard phase to be dispersed in a Ni-based alloy like Ti carbides and nitrides, and react with Cr, W, etc. to form carbides and nitrides, and wear resistance. Contribute to the improvement of. Its content is 0.4% by weight
If the amount is less than 3, abrasion resistance is insufficiently improved, while 3% by weight
If it exceeds 1.0, carbides and nitrides become excessive, the attacking property of the mating material increases and the mechanical properties are impaired.
Limit to wt%. However, when carbide is added as the hard layer, wear resistance is secured by the carbide, so the N content is set to the range of 0 to 3% by weight.

Fe is added to improve strength at low temperatures. However, if it is less than 3% by weight, the action is insufficient, and if it exceeds 6% by weight, the corrosion resistance decreases, so the content is limited to 3 to 6% by weight.

Since Cu contributes to the improvement of the corrosion resistance of the Ni-based alloy, as represented by Monel alloy (trade name) which is a Ni-Cu alloy, Cu is contained if desired. However,
In order to obtain sufficient corrosion resistance, it is desirable to contain 0.5% by weight or more. On the other hand, when the addition amount is large, the alloy is softened and wear resistance is deteriorated, so the content is set to 2% by weight or less. When the wear resistance is important, no addition is made.

Ni is an element effective in improving the corrosion resistance and has the effect of forming a hard boride together with B to improve the wear resistance. Therefore, the balance is Ni. In addition,
The balance Ni contains unavoidable impurities, but they are acceptable within a range that does not impair the effects of the present invention.

[0019]

EXAMPLES Examples of the present invention will be described below in comparison with comparative examples (conventional examples). In addition, in the following description, all component amounts are shown by weight%. First, N having the composition shown in Table 1
An i-based alloy (alloy A) was prepared as a part of the raw material powder, and the powders were weighed and mixed in the component ratios shown in Table 2 to prepare respective test mixed powders. The particle size of each raw material powder is as shown below. (Particle size) Alloy A: 10 to 44 μm CrB: 9 μm (average particle size) Cu: 44 μm or less WC: 1.9 μm (average particle size) TiC: 148 μm (average particle size) TaC: 2 μm (average particle size) TiN: 1.18 μm (average particle size)

A predetermined amount of a binder such as paraffin is further added to each mixed powder, and the mixture is wet-mixed in an organic solvent by a ball mill for 24 hours, and then dried to 250 to 500 μm.
Granulated to a particle size of. This granulated powder was molded by CIP or the like.
The obtained molded body is heated under an inert gas atmosphere at 350
Degreasing was performed by heating at ~ 500 ° C for 2 to 4 hours. Then, the degreased compact was sintered in a vacuum atmosphere. Specifically, in an atmosphere of 10 ⁻³ Torr or less, 1000
Hold at ℃ for 1 hour, then at 1180 ~ 1350 ℃ 3
Hold for 0 to 120 minutes to obtain a sintered body of the present invention. further,
This sintered body was cut and processed to prepare test pieces having a predetermined shape (Examples 1 to 10). For comparison, test pieces (Comparative Examples 1 and 2) made of conventional materials were prepared. Comparative material 1
Is a commercially available Ni-based corrosion resistant alloy, and Comparative Example 2 is a Ni-based self-fluxing alloy. In addition, Examples 1-10
Table 3 shows the total amounts of the components of Comparative Materials 1 and 2. Of the above-mentioned test pieces, Example 9 was subjected to area analysis structure observation by EPMA, and as shown in the photograph of FIG. 1, a composition of Ni—Fe—Cu—Cr was formed as a matrix, and the hard phase As TiC carbide and Cr-Mo
A complex boride of -WB was produced.

[0021]

[Table 1]

[0022]

[Table 2]

[0023]

[Table 3]

Next, in order to evaluate the characteristics of each test piece, its hardness was measured, and a corrosion test and a wear test were performed. In the corrosion test, the corrosion resistance was evaluated by immersing in 5% hydrofluoric acid for 30 hours at room temperature and measuring the corrosion weight loss. Further, in the wear test, in order to simulate adhesion wear between metals, an Ogoshi-type rapid wear tester was used, SKD11 equivalent material (HRC61) was used as the mating material, and final load was 18.9 kgf and friction speed was 2. The test was performed under the conditions of 37 m / S, friction distance of 200 m, room temperature, and no lubrication, and the wear amount was measured to evaluate the wear resistance. In addition, an abrasive wear test was conducted to simulate wear due to hard additives in the resin. Specifically, the mating material is the 320th S
Using iC polishing paper, load 2kgf, speed 3.6m / s
The test was performed at (60 reciprocations / minute). The wear amount is 40
The average value of wear reduction every 0 times was used.

The results of these tests are shown in Table 4. As a result, Comparative Example 1 (Ni-based corrosion resistant alloy) is excellent in corrosion resistance but inferior in wear resistance. For example, it is not a suitable material for molding a composite material in which glass fiber or the like is added to resin. Absent. Comparative Example 2 (Ni-based self-fluxing alloy)
Although it cannot be said that the wear resistance is sufficient, a certain degree of characteristics are secured. However, it is clearly inferior in terms of corrosion resistance.

On the other hand, the test pieces of Examples 1 to 10 were
The abrasive wear resistance is improved by carbides such as WC and TiC, and for example, wear due to the hard additive in the resin is prevented. In addition, the compound boride is effective as a lubricant. In the Ogoshi-type wear test, both the self (fixed test piece) and the mating material (rotating test piece) wear little, and With respect to the wear caused by the contact between the materials, the aggressiveness to the mating material is softened, and the adhesive wear between the metals is softened. Further, the amount of corrosion in the corrosion test is small, and for example, even in a highly corrosive environment due to the gas generated from the resin, the high Cr Ni matrix and the complex boride exhibit high corrosion resistance. As described above, the composite material of the present invention, unlike the comparative material, was excellent in both wear resistance and corrosion resistance. In the table, the amount of wear of the rotating test piece shows a negative value because the material of the fixed test piece adheres to the rotating test piece due to adhesion.

[0027]

[Table 4]

[0028]

As described above, according to the composite material of the present invention, the hard phase mainly composed of boride and carbide is N
Since the i-based alloy is used for bonding, not only high corrosion resistance but also excellent properties as a wear resistant material having both properties of adhesion resistance and abrasive wear resistance are obtained. Therefore, there is an effect that the optimum composite material can be obtained as a constituent sliding material such as a cylinder, a screw, a friction ring, a backflow prevention ring for a resin processing machine used under severe molding conditions.

[Brief description of drawings]

FIG. 1 is a photograph of a metal structure of a sintered body of Example (magnification: 2000 times).

Claims (3)

[Claims] 1. A composite material in which a hard layer mainly containing carbide and boride is dispersed in a Ni-based matrix, and the total amount of the matrix and the hard layer is B: 2 to 2.
6% by weight, Cr: 21 to 38% by weight, Mo: 8 to 22% by weight, W: 0.5 to 12% by weight, Fe: 3 to 6% by weight,
C: 0.4 to 3% by weight, Cu: 0 to 2% by weight,
Further, a high corrosion-resistant and abrasion-resistant composite material containing Ti: 2 to 20% by weight, Ta: 1 to 5% by weight, one or two kinds, and the balance being Ni and inevitable impurities. 2. A composite material in which a hard layer containing carbide, boride and nitride as main components is dispersed in a Ni-based matrix, and the matrix and the hard layer have a total amount of B: 2 to 6% by weight and Cr. : 21 to 38% by weight, Mo: 8
-22% by weight, W: 0.5-12% by weight, Fe: 3-6
% By weight, C: 0.4 to 3% by weight, N: 3% by weight or less, C
u: 0 to 2% by weight, further, Ti: 2 to 20% by weight, Ta: 1 to 5% by weight of 1 type or 2 types,
High corrosion resistance and wear resistance composite material characterized by the balance being Ni and inevitable impurities 3. The hard layer according to claim 1, wherein the total content of W, Ti and Ta is 6 to 25%.
High corrosion resistance and wear resistance composite material described in