JP3229140B2 - Corrosion-resistant wear-resistant high-strength Ni-base alloy and its composite material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a corrosion-resistant and abrasion-resistant material used as a constituent material of various members which simultaneously require corrosion resistance, abrasion resistance and strength, such as cylinders, screws and plungers of an injection molding machine or an extrusion molding machine. The present invention relates to a high strength Ni-based alloy and a composite material thereof.

[0002]

2. Description of the Related Art Members such as cylinders, screws, plungers and the like that constitute an injection molding machine or an extrusion molding machine have corrosion resistance, abrasion resistance and resistance to contact with a fluid which is pumped at a high pressure and a high speed. High strength is required.

Conventionally, as such constituent materials, (a)
Ni-based self-fluxing alloy, (b) WC particle-dispersed Ni-based self-fluxing alloy,
(C) Mo-Ni double boride alloy, and (d) corrosion resistance,
A wear-resistant Ni-based alloy is used.

(A) Ni-based self-fluxing alloy is Ni-Cr-B
-Si alloy, which has excellent corrosion resistance and wear resistance, has been widely used as a hardening material for steel surfaces.
(B) WC particle-dispersed Ni-based self-fluxing alloy is Ni-Cr-B
-An alloy in which WC particles are finely dispersed in a Si alloy,
Because of its excellent corrosion resistance and abrasion resistance, it is used as a mechanical part such as a barrel of a plastic molding machine (Japanese Patent Laid-Open No. Sho 62)
-197264).

[0005] (c) Mo-Ni based double boride alloy is an alloy in which a hard phase mainly composed of Mo ₂ NiB ₂ is bonded by a Ni-based binder phase, and is excellent in corrosion resistance and wear resistance. Therefore, it is suitable for a material used in a highly corrosive environment (Japanese Patent Publication No. 5-5889). Furthermore, (d) corrosion- and wear-resistant Ni-based alloys are Cr-Mo-W-V-B-S
It is an i-Ni alloy, and is useful for various constituent members requiring corrosion resistance and wear resistance (Japanese Patent Application Laid-Open No. 6-57360).

However, as for these alloy materials, materials having both abrasion resistance, corrosion resistance, and strength such as those having wear resistance are insufficient in corrosion resistance, and even if they have corrosion resistance, their strength is not sufficient. At present it is not found.

That is, (a) Ni-based self-fluxing alloy does not have sufficient corrosion resistance and wear resistance, and has a strength of about 0.8 G in transverse rupture strength.
Since it is as small as Pa, it cannot be used for mechanical parts that are subject to high stress. (B) WC particle-dispersed Ni-based alloys exhibit excellent wear resistance and corrosion resistance because the WC particles are uniformly dispersed, but the material strength is as small as about 0.9 GPa in the transverse rupture strength and high load mechanical parts. It is difficult to apply to

(C) Mo—Ni-based composite boride alloys are excellent in corrosion resistance and wear resistance, but have a transverse rupture strength of 1.5.
GPa is not enough. In addition, the sintering temperature is 1125
Since it is as high as １２1225 ° C., it is not suitable for joining with a steel material at the same time as sintering to form a composite material. At this temperature, the steel material deteriorates due to the coarsening of the crystal grains of the steel material. Although it is possible to perform joining such as brazing in a step different from the sintering step, there are problems such as an increase in cost. further,
(D) Corrosion-resisting and abrasion-resistant Ni-based alloys have insufficient bending strength and are difficult to use as high-load machine parts.

[0009]

SUMMARY OF THE INVENTION The corrosion-resistant and abrasion-resistant high-strength Ni-based alloy of the present invention is an alloy material which is excellent in corrosion resistance and abrasion resistance and has high strength and is suitable for members of an injection molding machine or an extrusion molding machine. It is intended to provide. Further, another object of the present invention is to provide a corrosion-resistant and abrasion-resistant high-strength Ni-based alloy composite material in which a composite material for metal-bonding such an alloy material and a steel material is simultaneously formed with sintering, and the composite material is formed. It is to provide at low cost.

[0010]

The corrosion-resistant and abrasion-resistant high-strength Ni-based alloy of the present invention has a B content of 0.6 to 3.2% by weight, a Si content of 0.5 to 8% by weight, and a Mo content of 5 to 37%. % By weight, and the balance is composed of Ni and unavoidable impurities, and Ni boride and Mo boride are dispersed in the Ni-based bonding phase. The corrosion-resistant, abrasion-resistant, high-strength Ni-based alloy composite material of the other invention of the present invention has a B content of 0.6 to 3.2% by weight, a Si content of 0.5 to 8% by weight, and a Mo content.
With a corrosion-resistant, wear-resistant, high-strength Ni-base alloy in which Ni-boride and Mo-boride are dispersed in a Ni-based binder phase. , And steel and compounded by metal bonding,
It is characterized by the following.

Hereinafter, the present invention will be described in detail. First,
The function of each component element of the Ni-based alloy of the present invention and its appropriate range will be described. In addition, in this specification, it is weight% unless there is particular notice. B lowers the sintering temperature and forms borides with Ni and Mo to increase the wear resistance of the alloy. Since the transverse rupture strength is lowered regardless of whether the B content is high or low, the B content is 0.6 to 3.2%, preferably 1.0 to 3.2%.
3.1%.

Since Si lowers the sintering temperature in the same manner as B, it is effective to combine with steel at the same time as sintering. If the sintering temperature is low, sintering and compounding can be performed simultaneously without deteriorating the steel material, which is economically advantageous. The sintering temperature decreases as the Si content increases, but when it exceeds 8%, the transverse rupture strength sharply decreases. Even when the amount of Si is small, the bending strength decreases and the sintering temperature increases, so the lower limit is set to 0.5%. Therefore, the Si content is 0.5 to 8%,
Preferably, it is 2.5 to 7%.

Mo forms borides with B, has the effect of improving the wear resistance and improving the corrosion resistance of the binder phase mainly composed of Ni. In addition, it has the effect of refining the crystal grains of the alloy and significantly increasing the strength and bending strength. Such an effect occurs when Mo is 5%, and when it exceeds 40%, on the contrary, the transverse rupture strength decreases. This decrease in bending strength is considered to be due to an increase in sintering temperature due to an increase in Mo, and as a result, crystal grains are coarsened by high-temperature sintering. Therefore, the Mo content is 5
To 37%, preferably 15 to 32%.

The contents of B, Si and Mo, which show the most excellent corrosion resistance, wear resistance and strength, and the preferable sintering temperature for forming a composite with a steel material, are as follows. 8%, Si is 3.5 to 6.0%, Mo is 2
0 to 30%.

Next, the method for producing the corrosion-resistant, abrasion-resistant, high-strength Ni-based alloy of the present invention will be described. Ni-based alloys are B, S
i, Mo, Ni powder or two of these elements
The alloy powder containing more than one kind is weighed in a predetermined amount, crushed and mixed by a rotary ball mill for 48 hours, and then press-molded and sintered.

The sintering is performed in a vacuum and a reducing gas. Moreover, you may perform by other methods, such as hot isostatic sintering. The sintering temperature varies depending on the composition of the alloy.
Perform at 30 ° C. If the sintering temperature is too low, the densification is not complete and the performance is reduced, and if it is too high, the transverse rupture strength is reduced due to the coarsening of the crystal grains.

The sintered alloy is MoB, Mo ₂ NiB
_{It has a} structure in which fine particles of boride such as ₂ , Ni ₂ B, and Ni ₃ B are uniformly dispersed in a Ni bonding phase. Mo and Si are dissolved in the Ni bonding phase.

Next, a description will be given of the production of a composite material which is formed by metal bonding between the corrosion-resistant and abrasion-resistant high-strength Ni-based alloy of the present invention and a steel material. When a plate-like steel material is combined with the corrosion-resistant and abrasion-resistant high-strength Ni-based alloy of the present invention, Ni
When sintering is performed in a state where the forming of the base alloy is in direct contact, the appearance of the liquid phase causes sintering of the formed body, and at the same time, the steel material and the Ni-based alloy are joined to form a composite.

The corrosion-resistant, abrasion-resistant, high-strength Ni of the present invention is applied to the outer diameter portion of a cylindrical steel material or the inner diameter portion of a tubular steel material.
In the case of joining and combining the base alloys, the shrinkage of the Ni-based alloy compact during sintering is anticipated, and the appearance of the liquid phase in the final sintering process causes the steel and Ni-based alloy to be combined. Is done.

The steel material used in the composite with the corrosion-resistant and abrasion-resistant high-strength Ni-base alloy of the present invention will be described. The expansion coefficient of the corrosion-resistant wear-resistant high-strength Ni-based alloy of the present invention is 10 to 11 ×.
10 ⁻⁶ / ° C., which is close to 13% Cr steel. Considering the residual stress of the joint surface after the composite, SUS420J2, SUS440C, SUS4
A stainless steel such as 30 is preferred. When the formed body of the Ni-based alloy has a simple shape, it can be combined with carbon steel such as S25C.

As a method of compounding the corrosion-resistant and abrasion-resistant high-strength Ni-base alloy of the present invention with a steel material, an alloy powder having the same composition as that of the Ni-base alloy is produced in advance by a water atomization method, a gas atomization method, or the like. There is also a method of performing thermal spraying, remelting or overlaying using the alloy powder.

[0022]

EXAMPLES The present invention will be further described below with reference to examples. Example 1 In manufacturing the Ni-based alloy of the present invention, sample Nos. 1 to 5 alloy powders having the mixing ratios of the raw material powders shown in Table 1 were mixed, and mixed and pulverized in ethyl alcohol by a rotary ball mill. Next, the mixed alloy powder was dried, pressed, and sintered in a vacuum.

[0023]

[Table 1]

Table 2 shows the sintering temperatures of the sample numbers 1 to 5 of the corrosion-resistant and abrasion-resistant high-strength Ni-base alloy of the present invention. Each sintering time is 10 minutes. Various performance tests such as hardness, specific wear, corrosion resistance and bending strength were performed. Table 2 shows the test results.

The conditions of various performance tests are as follows. (1) Wear test Test machine: Ogoshi quick wear test machine Test conditions: Friction speed 2.0 m / sec Friction distance 600 m Final load 18.6 kgf Counterpart material SKD11 (HRC58) (2) Corrosion test Corrosion solution 20% hydrochloric acid solution ( (22 ° C) Immersion time 5Hr (3) Bending test Test method JIS H5501 3-point bending buckling test Specimen dimensions 4 × 8 × 24mm, grinding

[0026]

[Table 2]

The sintering temperature, corrosion loss, specific wear, hardness, and transverse rupture strength of the corrosion-resistant and abrasion-resistant high-strength Ni-based alloy of the present invention and four conventional alloys as comparative examples were compared. Table 3 shows the results.

[0029]

[Table 3]

As can be seen from Table 3, the alloys of the present invention occupy an even higher rank than conventional alloys in terms of corrosion resistance, wear resistance, and strength, and are generally superior. In particular, the corrosion weight loss is 0.1 mg / cm ² · hr or less, showing extremely excellent corrosion resistance, and has the same or better performance than conventional alloys in terms of wear resistance and strength (flexural strength). I have.
Furthermore, since sintering at a relatively low temperature is possible, there is an advantage that compounding with a steel material can be performed simultaneously with sintering.

Example 2 An example in which the disk-shaped compact of the corrosion-resistant and abrasion-resistant high-strength Ni-based alloy of the present invention was combined with a steel material simultaneously with sintering will be described below. The target component of the Ni-based alloy is 19.2% by weight.
% NiB, 4% Si, 25% Mo, and the balance of Ni were blended with the respective raw material powders, and pulverized and mixed in ethyl alcohol by a rotary ball mill for 48 hours. Thereafter, drying and press molding were performed to prepare a disk-shaped molded body having the shape shown in FIG. The dimensions of this compact are 5 mm thick and 35 mm in diameter.
m, the density was about 50%.

As shown in FIG. 1 (b), the disc-shaped compact was sintered on a steel SUS420J2 at 1070 ° C. for 10 minutes in a vacuum to form a composite.
The dimensions of the sintered body were reduced to 3.4 mm in thickness and 30.2 mm in diameter.

After polishing the cross section of the contact surface between the SUS420J2 material and the sintered body shown in FIG. 1 (c) and observing it with an optical microscope, it was confirmed that both were strongly bonded to the metal. In this connection, a liquid phase is generated by sintering, and SUS42
It is considered that this was performed by getting wet with 0J2 material.
This sintered and composited material is machined,
Finished to predetermined dimensions and used as a member for a plastic molding machine.

Embodiment 3 An embodiment in which a steel material is sintered and compounded on the outer diameter portion of a cylinder of the corrosion-resistant and abrasion-resistant high-strength Ni-based alloy of the present invention will be described below. The target components of the Ni-based alloy are 6% NiB, 7% Si,
Each raw material powder was blended so as to be 0% Mo and the balance was Ni, and the mixture was pulverized and mixed in ethyl alcohol by a rotary ball mill for 48 hours. Then, it dried and was shape | molded by the rubber press, and the molded object was processed into the cylindrical shape shown to Fig.2 (a). The dimensions of the molded product were an outer diameter of 50 mm, an inner diameter of 27 mm, a height of 48 mm, and a density of about 50%.

As shown in FIG. 2B, a round bar made of SUS440C material is inserted and set at the center of the cylindrical molded body.
Sintering and compounding were performed at 1120 ° C. for 10 minutes in a vacuum. The outer diameter of the SUS440C round bar was φ23.0 mm in consideration of the sintering shrinkage of the compact.

As shown in FIG. 2 (c), the cylindrical compact shrinks due to sintering and compounding, and its size is an outer diameter φ4.
It shrank to 0 mm and height 40 mm. According to the observation with an optical microscope, the round bar steel material and the sintered body are firmly metal-bonded by the generation of the liquid phase from the molded body. After sintering and compounding, the composite material is finished to a predetermined size by machining and used as a screw for a plastic molding machine.

[0037]

According to the present invention, an alloy material having corrosion resistance, abrasion resistance, and high strength, and suitable for machine parts subjected to high load is obtained. In addition, since the Ni-based alloy of the present invention has a relatively low sintering temperature, it can be combined with steel at the same time as sintering, which is advantageous in terms of efficient production and cost.

[Brief description of the drawings]

FIG. 1 is a view for explaining a method for producing a composite material in which a composite of a disk-shaped formed body of a Ni-based alloy and a steel material according to the present invention is simultaneously formed with sintering.

FIG. 2 is a view for explaining a method of manufacturing a composite material in which a composite of a cylindrically formed Ni-based alloy and a round bar steel material of the present invention is simultaneously formed with sintering.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-196353 (JP, A) JP-A-4-337046 (JP, A) JP-A-62-197264 (JP, A) JP-A-1 116046 (JP, A) JP-A-4-337047 (JP, A) JP-A-6-57360 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C22C 19/03 C22C 1 / 10 C22C 32/00

Claims (2)

(57) [Claims] 1. B is 0.6 to 3.2% by weight and Si is 0.5% by weight.
-8% by weight, Mo is 5-37% by weight, and the balance is Ni
And it is composed of unavoidable impurities, wherein the Ni boride binder phase of Ni-base and Mo boride are dispersed, corrosion abrasion resistance high strength Ni-based alloy. 2. B is 0.6 to 3.2% by weight and Si is 0.5% by weight.
-8% by weight, Mo is 5-37% by weight, and the balance is Ni
And unavoidable impurities, and Ni-bonded
Corrosion and abrasion resistance with Ni boride and Mo boride dispersed in the phase
Corrosion-resistant abrasion-resistant high-strength Ni characterized by compounding a wear-resistant high-strength Ni-based alloy and a steel material by metal bonding.
Base alloy composite.