JPH08319530A - Composite material with high wear resistance and corrosion resistance - Google Patents

Abstract

PURPOSE: To form a homogeneous lining layer having excellent wear resistance and corrosion resistance on the internal surface of a base material of cylinder. CONSTITUTION: This material is a composite material for lining the internal surface of a cylinder, prepared by dispersing carbide reinforcement grains in a matrix. At this time, the matrix is composed of an Ni-base self-fluxing alloy which has a composition consisting of 2-4% B, 10-20% Cr, 2-5% Fe, 3-6% Si, 0.1-1% C, and the balance Ni with inevitable impurities and containing, if necessary, 2-3% Mo and 1-3% Cu, and the carbide reinforcement grains are composed of NbC contained by 10-30% by weight based on the composite material. By this method, the lining layer, having excellent wear resistance and corrosion resistance and free from dispersion of these properties according to positions, can be formed on the internal surface of a cylinder.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high wear and corrosion resistant composite in which a hard phase mainly composed of carbide and boride having high corrosion resistance and high wear resistance is bonded by a Ni-based self-fluxing alloy matrix having high corrosion resistance. It is about materials. For example, it is suitable as a cylinder material for a resin processing machine, which is intended for plastics such as plastics mixed with abradable reinforcing materials such as glass fibers and corrosive plastics.

[0002]

2. Description of the Related Art Cylinder materials for extruders and injection machines in resin processing machines are liable to be worn by the object to be machined, or are susceptible to cohesive wear due to contact between metals, and are therefore made of materials having excellent wear resistance. There is a need to. Therefore, conventionally, Cr
Steel cylinders made of self-fluxing wear-resistant Ni-based alloys with improved wear resistance due to crystallization of boron-containing particles and carbide particles, and composite materials in which hard particles such as WC are added to Ni-based self-fluxing alloys. A cylinder lined on the inner surface of the base material is used, and as a lining method for these composite materials, casting or centrifugal casting is generally adopted.

[0003]

However, in the above-mentioned composite material, since the specific gravity of Cr boride particles and the like is smaller than that of the Ni-based alloy that is the matrix, the Cr boride particles are formed when the lining layer is formed. Floats in the molten Ni-base alloy due to the difference in specific gravity, and when centrifugal casting is used, they are densely packed on the inner peripheral side of the lining layer. For this reason, good wear resistance is exhibited in the surface layer portion of the lining layer in which Cr boride particles are densely packed, but when the lining layer is gradually worn out, a layer with little or no Cr boride particles is exposed to show wear resistance. However, there is a problem of rapid deterioration. In addition, when two layers are separated into a layer in which Cr boride particles or the like are densely packed and a layer in which there is almost no Cr boride particles, zaku is likely to occur in a layer with few Cr boride particles, which may deteriorate the mechanical properties of the product. Also, in the casting method in which the cylinder is made vertical and the lining layer is formed on the inner peripheral surface thereof, the distribution of Cr boride particles in the vertical direction of the cylinder varies due to the above-mentioned difference in specific gravity, although it is not so remarkable as in the centrifugal casting method. The wear resistance of the lining layer becomes non-uniform in the axial direction.

On the other hand, when lining a composite material to which WC particles are added, on the contrary, WC
Since the specific gravity of the particles is large, the WC particles settle in the molten Ni-based alloy due to the difference in the specific gravity, and the WC particles are separated into a dense layer and a layer in which the WC particles do not exist. According to the centrifugal casting method, the layer without WC is formed on the surface side of the lining layer, but the layer without WC has a low hardness, so that sufficient wear resistance cannot be obtained. Since it adheres to the surface and causes adhesive wear, it is necessary to remove it by machining, which is one of the causes of lowering productivity.
In addition, the Ni-based self-fluxing alloy matrix that has been conventionally used has excellent corrosion resistance, but recently, due to the higher functionality of resins, more and more corrosive materials have been obtained. Is not enough. The present invention has a basic object to solve the above problems, and provides a composite material which is excellent in both wear resistance and corrosion resistance and which is capable of forming a uniform lining layer without variation in these characteristics depending on parts. The purpose is to

[0005]

In order to solve the above problems, the high wear and corrosion resistant composite material of the first invention of the present invention is a composite material in which carbide reinforced particles are dispersed in a matrix and lined on the inner surface of a cylinder base material. The material, wherein the matrix is, by weight, B: 2-4%, Cr: 10-2.
0%, Fe: 2-5%, Si: 3-6%, C: 0.1
1% is contained, the balance is made of Ni-based self-fluxing alloy consisting of Ni and inevitable impurities, and the carbide-reinforced particles are made of 10 to 30% by weight of NbC with respect to the composite material. To do.

The high wear and corrosion resistant composite material of the second invention is
A composite material in which carbide-reinforced particles are dispersed in a matrix and lined on the inner surface of a cylinder base material, wherein the matrix is B: 2-4% by weight and Cr: 10-20.
%, Fe: 2 to 5%, Si: 3 to 6%, C: 0.1 to 1
%, Mo: 2 to 3%, Cu: 1 to 3%, with the balance being Ni-based self-fluxing alloy consisting of Ni and inevitable impurities, and the carbide-reinforced particles are 1% by weight with respect to the composite material.
It is characterized by being composed of 0 to 30% of NbC.
The method for lining the inner surface of the cylinder base material with the composite material of the present invention is not particularly limited, but as described below, it is particularly suitable for forming a lining layer by a casting method or a centrifugal casting method.

[0007]

In the composite material of the present invention, the Ni-based self-fluxing alloy matrix and NbC, which is a carbide-reinforced particle, have almost the same specific gravity (about 7.8), and this is cast or centrifugally cast into a cylinder. When lining the inner surface of the base material, NbC, which is a carbide-reinforced particle, is not unevenly distributed in the matrix, and is uniformly dispersed in the matrix over the entire area of the lining layer. Therefore, there is no variation in abrasion resistance depending on the position, and it is possible to prevent zaku caused by the separation of the lining layer into two layers. Furthermore, if the reinforced layer is machined to a predetermined size, the reinforcement particles are uniform. It is possible to obtain the lining cylinders dispersed in, and it is also possible to reduce the excess thickness portion of the lining layer. Hard (Hv about 2200) carbide-reinforced particles NbC are uniformly dispersed in the obtained lining layer, which improves the abrasive wear resistance. Also,
In the matrix, in addition to NbC, a self-lubricating Cr boride crystallized by the composition of a Ni-based self-fluxing alloy (Cr
B) is mixed, the wear resistance of the self is excellent, and the attacking property to the mating material is smaller than that of the case where only the carbide-reinforced particles are used. Further, the Ni-based self-fluxing alloy has excellent corrosion resistance and is effective against ordinary corrosive resins.
By adding Cu, good corrosion resistance is exhibited even with a resin having a stronger corrosiveness. Next, the action of the components of the composite material of the present invention and the reasons for limiting the content will be described. The content of the carbide particles is shown by weight% with respect to the entire composite material,
The components of the Ni-based self-fluxing alloy are shown in% by weight with respect to the entire matrix.

(Carbide reinforced particles) NbC improves wear resistance as carbide reinforced particles.
If the content is less than 10% by weight, the effect is insufficient. On the other hand, if it exceeds 30%, the amount of carbides becomes excessive, which increases the aggressiveness to the mating material and reduces the mechanical properties of the alloy. Limited to 30%. Further, considering the wear resistance of itself and the aggressiveness to the mating material, it is preferable to further set the lower limit to 15% and the upper limit to 25%.

(Ni-based self-fluxing alloy) B is added in order to impart self-fluidity to the Ni-based alloy, and Cr in the matrix is added.
It is an indispensable element for forming CrB, which combines with Al and has self-lubricity and contributes to wear resistance. However, B
If the content is less than 2%, their actions are insufficient, while if it exceeds 4%, the toughness is significantly reduced.
The content is limited to 2-4%.

[0010] Cr not only constitutes a hard phase as a boride having a self-lubricating property, but also forms a solid solution in the binder phase to improve corrosion resistance, wear resistance, heat resistance and oxidation resistance. . If the content is less than 10%, the wear resistance and the corrosion resistance are insufficient, and if it exceeds 20%, the improvement in the corrosion resistance commensurate with the content is not recognized, and the toughness is also reduced. It needs to be limited to 20%. Further, in order to obtain sufficient wear resistance, the range of 15 to 20% is preferable.

Si, like B, is added to give self-fluxing property to the Ni-based alloy, but if it is less than 3%, its action is insufficient, and if it exceeds 6%, the toughness is remarkably reduced. Limited to ~ 6%. For the same reason, it is desirable to set the lower limit to 3.5% and the upper limit to 5%.

[0012] C lowers the melting point of the Ni-based alloy and reacts with Cr to form a carbide, which contributes to the improvement of wear resistance like NbC. If the content is less than 0.1%, the improvement in wear resistance is insufficient, and if it exceeds 1%, the mechanical properties are impaired, so the content is limited to 0.1-1%.

Fe is added to improve the strength at low temperatures. However, if it is less than 2%, its action is insufficient, and if it exceeds 5%, the corrosion resistance is lowered, so the content is limited to 2 to 5%. For the same reason, it is desirable to further set the upper limit to 3.5%.

Mo has the function of increasing the corrosion resistance to a reducing atmosphere such as hydrofluoric acid, and is contained when higher corrosion resistance is required. However, if it is less than 2%, the effect is not so great, and if the addition amount is large, N
The melting point of the i-based self-fluxing alloy matrix increases, making it difficult to apply to centrifugal casting, so the content is limited to 2 to 3%. Cu is
As represented by Monel alloy (trade name) which is a Ni-Cu alloy, it contributes to the improvement of the corrosion resistance of the Ni-based alloy,
Included when higher corrosion resistance is required. However, in order to obtain sufficient corrosion resistance, the content of 1% or more is desirable. On the other hand, if the amount of addition is large, the alloy softens and wear resistance deteriorates, and in addition, the melting point of the Ni-based self-fluxing alloy matrix increases, so the content was made 1 to 3%.

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.

[0016]

EXAMPLES Examples of the present invention will be described below in comparison with comparative examples (conventional examples). First, the Ni-based self-fluxing alloys (alloys A to D) shown in Table 1 were prepared as a part of the raw material powder, and the alloy powder was mixed with NbC particles or WC at a mixing ratio shown in Table 2 except for a part. The particles and CrB particles were weighed and mixed to prepare respective test mixed powders. Next, each of the mixed powders is heated in a heating furnace at 120
After holding at 0 ° C. for 30 minutes, it was cooled in a furnace to obtain a molten material of the present invention. Further, this ingot was cut and processed to produce test pieces having a predetermined shape (Examples 1 to 5 and Comparative Examples 1 to 4). Comparative Examples 1 and 2 which do not contain NbC correspond to conventional materials made of commercially available Ni-based self-fluxing alloy. For reference, the total amount of the components of each test piece is shown in Table 3.

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

[Table 3]

When the metal structures of the above-mentioned test pieces were observed except Comparative Examples 1 and 2, N was found in the test pieces of Examples.
While bC was uniformly dispersed (FIG. 1), in Comparative Examples 3 and 4 (FIGS. 2 and 3), it was confirmed that the reinforcing particles were clearly unevenly distributed in the lower part or the upper part. This is because in Comparative Example 3, WC has a larger specific gravity than the matrix, and in Comparative Example 4, CrB has a smaller specific gravity than the matrix. In addition, FIG. It is a metallographic photograph of the test piece of No. 4. Next, except for the above Comparative Examples 3 and 4, a corrosion test and an abrasion test were performed to evaluate the characteristics of each test piece. The corrosion test was carried out by two methods: A: immersion in 5% hydrofluoric acid at room temperature for 30 hours, and B: boiling in 1% hydrochloric acid for 5 hours, and the corrosion weight loss was measured to evaluate the corrosion resistance. 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. 37m /
s, friction distance of 200 m, room temperature, and no lubrication conditions, and the abrasion resistance was evaluated by measuring the wear amounts of the test piece (fixed test piece) and the mating material (rotating test piece), respectively.
In addition, an abrasive wear test was conducted to simulate wear due to hard additives in the resin. In particular,
2kg load using No. 320 SiC polishing paper as mating material
The test was performed at f and a speed of 3.6 m / s (60 reciprocations / minute). The amount of wear was the average value of the amount of wear reduction every 400 times.

The results of these tests are shown in Table 4. As a result, Comparative Examples 1 and 2 (Ni-based self-fluxing alloys) have a certain degree of corrosion resistance, but are inferior in wear resistance. For example, for molding composite materials in which glass fiber or the like is added to resin. Is not a suitable material. In addition, especially in the results of the Ogoshi-type wear test, the amount of wear is remarkably large, and the material of the fixed test piece adheres to the rotating test piece due to adhesive wear, and the weight increase of the rotating test piece Is shown).

On the other hand, the test pieces of Examples 1 to 5 have improved abrasive wear resistance due to Nb carbide particles, and prevent wear due to, for example, hard additives in the resin. In addition, Cr boride is effective as a lubricant,
In the Ogoshi-type wear test, the amount of wear of both itself (fixed test piece) and mating material (rotating test piece) is small, and the aggression against the mating material is reduced in the wear caused by the metal-to-metal contact of the constituent members. Reducing adhesive wear between each other. Further, when comparing Example 1 and Example 3, the amount of Cr boride is larger in Example 3 due to the difference in the Ni-based self-fluxing alloy component, and therefore the effect of reducing the aggressiveness to the mating material is greater. Further, in Examples 4 and 5 in which the content of NbC was increased, the wear resistance of itself was improved in accordance with the increase in the content of NbC, but in the results of the Ogoshi-type wear test, the aggressiveness to the mating material Is also slightly increasing. Also, Mo,
In Example 3 in which Cu was added, the amount of corrosion in the corrosion test was small, and for example, even in a highly corrosive environment due to the gas generated from the resin, the Ni matrix containing high Cr and Mo and Cu exhibits high corrosion resistance. As described above, the composite material of the present invention, unlike the comparative example, was excellent in both wear resistance and corrosion resistance.

[0023]

[Table 4]

[0024]

As described above, according to the composite material of the present invention, NbC, which is a hard material, can be converted into Ni that is excellent in corrosion resistance.
Since it is dispersed in the base self-fluxing alloy, there is an effect that not only high corrosion resistance but also excellent properties as a wear resistant material having both properties of adhesion resistance and abrasive wear resistance can be obtained. Therefore, there is an effect that an optimum composite material can be obtained as a constituent sliding material such as a cylinder member for a resin processing machine used under severe molding conditions.

[Brief description of drawings]

FIG. 1 shows an example No. 4 metallographic image (magnification 50
Times).

FIG. 2 is a photograph of a metal structure of Comparative Example 3 (WC is a hard material) (magnification: 50 times).

FIG. 3 is a metallographic photograph (magnification: 50) of Comparative Example 4 (using CrB as a hard material).

Claims (2)

[Claims] 1. A composite material in which carbide-reinforced particles are dispersed in a matrix and lined on the inner surface of a cylinder base material, wherein the matrix is B: 2 to 4% by weight and C.
r: 10 to 20%, Fe: 2 to 5%, Si: 3 to 6%,
C: 0.1 to 1%, with the balance being Ni-based self-fluxing alloy consisting of Ni and unavoidable impurities, wherein the carbide-reinforced particles are 10 to 30% by weight of NbC based on the composite material. High wear and corrosion resistance composite material characterized by 2. A composite material in which carbide reinforced particles are dispersed in a matrix and lined on the inner surface of a cylinder base material, wherein the matrix is B: 2 to 4% by weight, and C.
r: 10 to 20%, Fe: 2 to 5%, Si: 3 to 6%,
C: 0.1 to 1%, Mo: 2 to 3%, Cu: 1 to 3%, with the balance being a Ni-based self-fluxing alloy composed of Ni and inevitable impurities. A high wear and corrosion resistant composite material characterized by comprising 10 to 30% by weight of NbC.