JPH05132734A - Composite material having wear resistance and corrosion resistance - Google Patents

Abstract

PURPOSE:To provide a composite material having excellent characteristics in corrosion resistance, wear resistance, and strength and suitable, e.g., for cylinder material and screw material for extruding machine and injection machine for resin working machine. CONSTITUTION:Hard phases composed essentially of carbide and boride are bound with Ni-base or Co-base matrix. The composition consists of, in total (by weight), 1.5-5% B, 5-15% Cr, 25-50% Mo, 10-25% W, 2-4% Fe, 0.5-24 C, and the balance Ni or Co with inevitable impurities and further contains, if necessary, 0.5-2% Cu. By this method, the wear- and corrosion-resistant composite material having sufficiently excellent characteristics in corrosion resistance, wear resistance, and strength can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wear-corrosion-resistant composite material in which a hard phase mainly composed of a carbide and a boride having high corrosion resistance and high wear resistance is bound by a Ni group or a Co group matrix. It is about. For example, it is suitable as a cylinder material or a screw material for a resin processing machine of a plastic material such as highly corrosive plastic or rubber. In particular, it is suitable as a corrosion-resistant and wear-resistant material for a resin processing machine for a compound that requires corrosion resistance against hydrochloric acid and hydrofluoric acid and also requires wear resistance.

[0002]

2. Description of the Related Art Cylinders and screw materials of extruders and injection machines in resin processing machines are liable to be abraded by an object to be machined or contact-abraded between metals, and are therefore made of materials having excellent abrasion resistance. There is a need. Therefore, as the above-mentioned material, conventionally, a self-fluxing wear resistant Ni alloy excellent in wear resistance or a composite material obtained by adding hard particles such as WC to a Ni-based self-fluxing alloy has been used.

[0003]

By the way, recently, due to the high functionality of the molding material, the environment in which the resin processing machine is used is becoming more severe. For example, the resin is generated in the molding operation under high temperature conditions. Exposed to corrosive gases and susceptible to corrosion. Therefore, unlike conventional materials, it is not possible to focus only on wear resistance for mechanical materials,
Properties with excellent corrosion resistance and strength are required. However, although the self-fluxing wear-resistant Ni alloy and the WC-added composite material described above have good wear resistance, they do not have sufficient corrosion resistance or strength.

On the other hand, a Ni--Cr--Mo alloy is known as a material having excellent corrosion resistance, and it may be actually used. However, this material has drawbacks that it does not have sufficient wear resistance, and that it tends to cause adhesion and galling due to contact between members. As described above, in the conventional materials, the material excellent in corrosion resistance does not have sufficient abrasion resistance, and the material excellent in abrasion resistance has insufficient corrosion resistance and strength. For this reason, development of materials excellent in all properties of wear resistance, corrosion resistance, and strength has been progressed, but material satisfying all of these properties has not been achieved yet. The present invention has been made against the background of the above circumstances, has high corrosion resistance, and also has excellent wear resistance and strength, and can withstand use in a highly corrosive environment in severe resin processing machines. It is an object of the present invention to provide a wear-corrosion-resistant composite material which can be manufactured and has higher strength than existing materials.

[0005]

In order to solve the above-mentioned problems, the inventors of the present invention have developed a hard phase mainly composed of Mo-Cr type boride and a hard alloy in which carbides such as W and Mo are dispersed. I paid attention. Furthermore, the present inventors have found that, in the process of developing an abrasion-corrosion-resistant material, this boride has not only high hardness but also fine abrasion to have excellent abrasion-corrosion resistance and strength. Boride and W, Cr,
By combining the Mo carbide and the Ni-based or Co-based alloy, the composite material of the present invention having excellent wear and corrosion resistance is obtained.

That is, the wear-resistant and corrosion-resistant composite material of the present invention is a composite material in which a hard phase composed mainly of a carbide and a boride is bonded by a Ni-based or Co-based matrix, and the hard phase and the matrix are: In total, B:
1.5-5% by weight, Cr: 5-15% by weight, Mo: 25-
50% by weight, W: 10 to 25% by weight, Fe: 2 to 4% by weight, C: 0.5 to 2% by weight, and optionally Cu: 0.5 to 2% by weight, The balance is Ni or C
It is characterized by comprising o and unavoidable impurities.

In the above hard phase, the main component is the boride which remains in the additive alloy or reacts with the contained components, and most of the boride consists of complex boride. Further, also in carbides, composite carbides 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 composition. 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 hardness can be obtained. In the above powder metallurgy, W,
Providing all or part of C as WC powder, Mo, C
All or part of r, B can be provided as MoB, CrB powder. These powders have a particle size of 3 to 10 μm so that fine carbides and borides can be dispersed in the matrix.
It is desirable to use those having a particle size of.

When the above powder is used, a master alloy powder having a composition as required within the scope of the invention is used. For example, Cr: 15 to 16%, Mo: 1
5 to 17%, W: 3 to 4%, Cr: 15 to 16
%, Mo: 31-32%, and a master alloy having the balance substantially Ni. The mother alloy powder is preferably manufactured by the atomization method because of its sinterability and uniformity of structure. A predetermined amount of WC powder, boride, and mother alloy powder are mixed by a ball mill or the like, and the mixed powder is molded and then sintered. For example, when performing by liquid phase sintering,
Sinter at 1000 to 1300 ° C. for 10 to 90 minutes. The sintering method is not limited to this, and other sintering methods such as HIP and hot pressing can be adopted in addition to the normal sintering method.

[0009]

In other words, according to the composite material of the present invention, as a result of various experiments, it was confirmed that the boride (mainly the compound boride) plays a role of a lubricant during sliding, and alleviates the aggressiveness to the mating material. ing. Further, the compound boride exhibits appropriate wear resistance and improves corrosion resistance. Further, by combining W and Cr carbides with the compound boride, adhesion wear between metals is reduced, and due to the wear resistance of carbides having high hardness, it effectively acts on abrasive wear. Therefore, according to the present invention, it is possible to obtain a material having excellent corrosion resistance, wear resistance and strength.

Next, the reasons for limiting the components of the present invention will be described.
B is an essential element for forming an M ₃ B ₂ type double boride (a surface analysis by an electron beam microanalyzer, confirmation of a result of an examination by X-ray diffraction) which becomes a hard phase.
If the B content is less than 1.5%, the wear resistance becomes poor.
On the other hand, if it exceeds 5%, the amount of the hard phase increases and the strength decreases, so the above range is set. Mo reacts with B to form a double boride. Further, it has the effect of increasing the corrosion resistance to a reducing atmosphere such as hydrofluoric acid, and a Mo amount of 25% or more is required to increase the corrosion resistance. However, if it exceeds 50%, a brittle intermetallic compound is formed and corrosion resistance is deteriorated, so the above range is made.

[0011] Cr reacts during sintering to form a carbide, forms a hard phase as a boride, and also forms a solid solution in the binder phase, resulting in corrosion resistance, wear resistance, heat resistance, and oxidation resistance. Has the function of improving. If it is less than 5%, the corrosion resistance is insufficient, and if it exceeds 15%, the toughness decreases, so the above range is made. W constitutes a hard phase to be dispersed in a Ni-based or Co-based alloy, and forms a double boride or a carbide by reacting with other components. If the content is less than 10%, the abrasion resistance cannot be sufficiently imparted, and 2
If it exceeds 5%, the material strength deteriorates, so the above range was made.

C, like W, constitutes a hard phase dispersed in a Ni-based or Co-based alloy, reacts with W, Mo, and Cr to form a carbide, which contributes to improvement of wear resistance.
If the content is less than 0.5%, the improvement in wear resistance is insufficient, and if it exceeds 2%, carbides become excessive, the attacking property of the mating material increases, and the mechanical properties are impaired, so the content is in the above range. Fe is added to improve the strength at low temperature. However, if the addition amount is large, the corrosion resistance decreases, so the above range is set.

Since Cu contributes to the improvement of the corrosion resistance of the Ni-based alloy, as represented by the Monel alloy which is a Ni alloy, Cu is added in an amount of 0.5% or more. However, if the amount of addition is large, the alloy will soften and the wear resistance will deteriorate, so the content was made 2% or less. In addition, when importance is attached to abrasion resistance, no addition can be made. Ni or Co 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, so the balance is Ni.
Or Co. In addition, inevitable impurities are present in the balance Ni or Co, but they are permissible as long as the effects of the present invention are not impaired.

[0014]

EXAMPLES Examples of the present invention will be described below in comparison with comparative materials (conventional examples). First, the alloys of the components shown in Table 1 and WC, MoB, and Cu were prepared as a part of the raw material powders with the following particle sizes, and each powder was weighed at the mixing ratio shown in Table 2 to prepare a test mixed powder. Were prepared respectively. (Particle size) Alloy A: 10 to 44 μm WC: 8 μm (average particle size) MoB: 3.5 μm (average particle size) Cu: less than 44 μm

[0015]

[Table 1]

[0016]

[Table 2]

A predetermined amount of paraffin-based, wax + resin-based, or resin-based binder is 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 subjected to CIP molding (pressure: 1 to 4 ton / cm ² ) using a rubber mold. The obtained molded body is heated at 350 to 500 ° C. for 2 to 4 in an inert gas atmosphere.
Degreasing was performed by heating for a time. And the molded body after degreasing,
1000 ° C in a vacuum atmosphere (10 ^-3 Torr or less)
After holding for 1 hour, the temperature was held at 1180 to 1270 ° C for 30 minutes to obtain a sintered body of the present invention. Furthermore, this sintered body was cut and processed, and test pieces (Examples 1 to 4) having a predetermined shape were cut out. For comparison, test pieces (comparative materials 1 to 3) made of conventional materials were prepared. Comparative material 1 is a commercially available Ni
Comparative material 2 is made of a Ni-base self-fluxing alloy, and Comparative material 3 is made of a Ni-base self-fluxing alloy having an average particle size of 60.
It was obtained by dispersing 40 μm of WC particles having a size of μm, and all were obtained by melting without powder metallurgy. Table 3 shows the total amounts of the components of Examples 1 to 4 and Comparative Materials 1 to 3.

[0018]

[Table 3]

When the surface of the above example was analyzed by EPMA and the structure was observed, a Ni-Fe-Cu-Mo composition was formed as a matrix as shown in the photograph of FIG. As (Mo, Cr, B)
And a carbide composed of (W, Mo, C). Next, in order to evaluate the characteristics of each test piece, its hardness and transverse rupture strength were measured, and a corrosion test and a wear test were performed. In the corrosion test, 1% hydrochloric acid was boiled, the test piece was immersed in this for 5 hours, and the corrosion weight loss of the test piece was measured to evaluate the corrosion resistance.

In the wear test, an Ogoshi-type wear tester was used to simulate adhesion wear between metals, a mating material equivalent to SKD11 (HRC61) was used, and final load was 18.7 kgf and friction speed. 2.37m / s, friction distance 2
The test was performed under the condition of 00 m, and the friction volume of the test piece was measured to evaluate the wear resistance. Further, an abrasive wear test was conducted in order to simulate the wear caused by the hard additive in the resin. Specifically, No. 320 SiC polishing paper was used as the mating material, and the load was 2 kgf and the speed was 3.6 m / s (60
The test was carried out at a reciprocating rate / minute, and the friction amount of the test piece was measured.
The average value for every 400 times was adopted as the friction amount.

The results of these tests are shown in Table 4. As a result, Comparative Material 1 (Ni-based corrosion resistant alloy) is excellent in corrosion resistance but inferior in wear resistance, and is suitable for molding a composite material in which glass fiber or the like is added to resin, for example. Not a material. Comparative material 2 (Ni-based self-fluxing alloy)
Wear resistance is not sufficient, but some properties are secured, but corrosion resistance is not sufficient. Further, Comparative Material 3 (Ni-based self-fluxing alloy + WC) has good wear resistance, but poor corrosion resistance and strength.

On the other hand, the test pieces of Examples 1 to 4 were
The abrasive wear resistance is improved by the carbides of W and Mo, and for example, wear due to the hard additive in the resin is prevented. Further, in the Ogoshi-type wear test, the compound boride is effective as a lubricant, and the amount of wear of the test piece itself is small. Furthermore, the amount of corrosion in the corrosion test is small, for example, even in a highly corrosive environment due to gas generated from the resin,
The generated hard material exhibits high corrosion resistance. Further, since fine hard materials are densely dispersed, it exhibits higher transverse rupture strength than the Ni-based self-fluxing alloy. As described above, the composite material of the present invention, unlike the comparative material, has excellent results in terms of wear resistance, corrosion resistance and strength.

[0023]

[Table 4]

[0024]

As described above, according to the composite material of the present invention, the hard phase mainly composed of carbide and boride is bonded to the base of the specific component by the Ni-based or Co-based alloy.
Not only wear resistance but also excellent properties as a high strength corrosion resistant material can be obtained. Therefore, there is an effect that the optimum composite material can be obtained as a constituent sliding material such as a cylinder and a screw for a resin processing machine used under severe molding conditions.

[Brief description of drawings]

1 is a photograph of a metal structure of a sintered body of Example 2. FIG.

Claims (4)

[Claims] 1. A composite material in which a hard phase mainly composed of a carbide and a boride is bound by a Ni-based matrix, and the hard phase and the matrix are contained in a total amount of B:
1.5-5% by weight, Cr: 5-15% by weight, Mo: 25-
50% by weight, W: 10 to 25% by weight, Fe: 2 to 4% by weight, C: 0.5 to 2% by weight, Cu: 0.5 to 2% by weight, and the balance Ni and inevitable impurities. Wear and corrosion resistant composite material consisting of 2. A composite material in which a hard phase mainly composed of a carbide and a boride is bound by a Ni-based matrix, and the hard phase and the matrix are contained in a total amount of B:
1.5-5% by weight, Cr: 5-15% by weight, Mo: 25-
Wear-corrosion-resistant composite material containing 50% by weight, W: 10 to 25% by weight, Fe: 2 to 4% by weight, C: 0.5 to 2% by weight, and the balance being Ni and inevitable impurities. 3. A composite material in which a hard phase mainly composed of carbide and boride is bound by a Co-based matrix, and the hard phase and the matrix are in a total amount of B:
1.5-5% by weight, Cr: 5-15% by weight, Mo: 25-
50% by weight, W: 10 to 25% by weight, Fe: 2 to 4% by weight, C: 0.5 to 2% by weight, Cu: 0.5 to 2% by weight, and the balance Co and unavoidable impurities Wear and corrosion resistant composite material consisting of 4. A composite material in which a hard phase mainly composed of a carbide and a boride is bound by a Co-based matrix, and the hard phase and the matrix are contained in a total amount of B:
1.5-5% by weight, Cr: 5-15% by weight, Mo: 25-
Abrasion-corrosion-resistant composite material containing 50% by weight, W: 10 to 25% by weight, Fe: 2 to 4% by weight, C: 0.5 to 2% by weight, and the balance being Co and inevitable impurities.