JP2605866B2 - Manufacturing method of composite compound dispersion type Cu-Zn-A (1) sintered alloy with excellent wear resistance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention exhibits excellent wear resistance when used, for example, as a block ring or bearing that requires seizure resistance under high speed and high load. The present invention relates to a method for producing a composite compound-dispersed Cu-Zn-Al-based sintered alloy.

[Conventional technology]

Generally, for example in the manufacture of block rings,
It is well known that a Cu-Zn-Al-based sintered alloy having a typical composition of Cu-28% Zn-6% Al is used.

[Problems to be solved by the invention]

On the other hand, in recent years, high performance and light weight of various devices have been avoided, and accordingly, it has been required that structural members also have excellent performance.
At present, -Zn-Al-based sintered alloys are not able to cope sufficiently with severe wear when applied under severe conditions.

[Means for solving the problem]

Therefore, the present inventors focused on the above-mentioned conventional Cu-Zn-Al-based sintered alloy from the above-described viewpoints and conducted research to impart excellent wear resistance thereto. A Cu-Zn-Al-based alloy powder having an oxide layer formed on the surface is prepared, and K and Al fluoride (hereinafter referred to as K-Al-F) powders are mixed, mixed, and pressed. After being molded into a body, it was manufactured by sintering and subjecting it to hot casting if necessary.
In Cu-Zn-Al-based sintered alloy, mainly aluminum oxide of the alloy powder surface portion K-Al-F is during sintering (hereinafter, indicated by Al ₂ O ₃₎ reacts with the surface oxide layer consisting of A liquid-phase composite compound is formed. As a result, the oxide layer is removed from the surface of the alloy powder, and the alloy powders come into direct contact with each other, so that the sinterability is significantly improved, and high strength and high toughness are obtained. In addition, the composite compound mainly composed of Al ₂ O ₃ is finely and uniformly dispersed in the alloy grain boundaries during the cooling process, and the finely dispersed composite compound mainly composed of Al ₂ O ₃ has a remarkably high hardness. Therefore, it was found that the wear resistance was improved.

The present invention has been made on the basis of the above-mentioned findings, and has been made by forming a surface oxide layer having an average layer thickness of 0.1 to 1 μm.
0.1 to 3% by weight of K-Al-F powder is mixed with u-Zn-Al-based alloy powder in a proportion of the whole, mixed, molded into a green compact, sintered, and if necessary. Composite compound dispersion type Cu-Zn- with excellent wear resistance by hot casting
It is characterized by a method for producing an Al-based sintered alloy.

In the method of the present invention, the average layer thickness of the surface oxide layer formed on the alloy powder is limited to 0.1 to 1 μm because, when the thickness is less than 0.1 μm, a hard composite compound dispersed in the alloy base material. Is too small to achieve the desired excellent wear resistance, while its thickness is 1 μm.
When m is exceeded, the dispersion ratio of the composite compound becomes too large,
The reason for this is that the toughness of the alloy is reduced. The reason why the K-Al-F powder is blended in an amount of 0.1 to 3% by weight is that the alloy powder surface is less than 0.1% by weight. Insufficient to completely react with the surface oxide of the part, the surface oxide layer remains in the alloy powder in a layer, and as a result, improvement in sinterability cannot be expected, and strength and toughness If the proportion is more than 3%, the proportion of Al ₂ O ₃ in the composite compound is reduced, and the hardness of the composite is reduced, and the desired excellent wear resistance is secured. It is based on the reason that it becomes difficult to do so.

In carrying out the method of the present invention, Cu-Zn-
The Al-based alloy powder contains Zn: 10 to 40% and Al: 0.3 to 6% by weight (hereinafter,% indicates weight%). Further, if necessary, (a) Fe, Ni and One or more of Co: 0.1
(B) Si: 0.1 to 3%, (c) One or more of W, Mo, and Cr: 0.1
-5%, (d) Mn: 0.1-5%, (e) Sn: 0.1-4%, contains one or more of the above (a)-(e), and the rest is inevitable with Cu It is desirable to have a composition composed of impurities, and the surface oxide layer has a temperature of 400 in air.
It is desirable to form the alloy powder by heating the alloy powder under the condition of holding at ~ 600 ° C for 10 to 120 minutes, but the Cu-Zn
When manufacturing powder from an Al-based alloy melt, it may be formed by atomizing in an oxidizing atmosphere.

Further, the K-Al-F powder used in the method of the present invention is prepared by mixing ammonium fluoride powder and potassium fluoride powder in a predetermined ratio, mixing them, and then heating them to about 900 ° C. in the atmosphere. Melt, for example, cast in a copper mold and quench,
Those manufactured by pulverizing to 0 mesh or less are preferable.

Further, the sintering of the green compact in the method of the present invention is performed in a non-oxidizing atmosphere such as hydrogen gas at a temperature of 800 to 900 ° C.
It is good to carry out under heating conditions.
It is preferable that the mold is forged in the air while being heated to 700 ° C., whereby the density is improved and the strength is improved.

〔Example〕

Next, the method of the present invention will be specifically described with reference to examples.

As a raw material powder, a surface oxide layer having the component composition shown in Table 1 and having the thickness shown in Table 1 was also formed by the above-mentioned heating oxidation method or atomizing atmosphere adjustment method. Various types of mesh Cu-Zn
An Al-based alloy powder was prepared, and an AlF ₃ powder and a KF powder were blended in a weight ratio of 6: 4, and a K-Al-F powder having a particle size of −350 mesh prepared under the above conditions was used. Similarly, blended at the ratio shown in Table 1 (total ratio), mixed for 60 minutes with a blender, and pressed into a green compact at a pressure of 5 ton / cm ² ,
Dew point: 0 ° C. in an atmosphere of H ₂ gas of ~-30 ° C., and sintered at 1 hour hold condition to a predetermined temperature in the range of 800 to 900 ° C., width: 10 mm
× height: 13 mm × length: a sintered body having the dimensions of 40 mm, and further heated to 700 ° C., in the atmosphere forging, to make the dimensions 10 mm × 10 mm × 40 mm Inventive methods 1 to 12 and comparative methods 1 to 6 were carried out, respectively.

In Comparative methods 1 to 6, the average layer thickness of the surface oxide layer of the alloy powder and the compounding ratio of the K-Al-F powder were different. This was performed under conditions outside the scope of the present invention.

Next, various Cu-Zn-Al-based sintered alloy which result obtained, the proportion of the complex compound, and crushing load for the purpose of evaluating the strength and toughness were measured for mainly composed of Al ₂ O ₃ in the alloy In order to further evaluate the wear resistance, test specimen shape: 8 mm x 8 mm x 30 mm, partner material: ring material of S35C steel (dimensions: outer diameter 30 mm x width 5 mm), oil: 10 w engine oil at 85 ° C, A block-on-ring wear test was performed under the following conditions: friction speed: 10 m / sec, final load: 4 kg, sliding distance: 1.5 km, and the specific wear amount was measured. Table 1 shows the results of these measurements.

〔The invention's effect〕

From the results shown in Table 1, the sintered alloys manufactured by the methods 1 to 12 of the present invention showed that the surface of the alloy powder was reacted with the oxide layer on the surface of the alloy powder and the K-Al-F powder during sintering. Since it is exposed and activated, the sinterability is remarkably improved, so that it also has high strength and high toughness, and is formed by the reaction between the surface oxide layer and K-Al-F powder.
Extremely hard and fine composites mainly composed of Al ₂ O ₃ have a uniformly dispersed structure, so they show excellent wear resistance, whereas sintered alloys produced by Comparative Methods 1-6 As can be seen, the average thickness of the surface oxide layer and the K-Al-
If at least one of the mixing ratios of the F powder is out of the range of the present invention, it is apparent that at least one of the above-mentioned characteristics becomes inferior.

For the purpose of comparison, K-Al-F in Method 5 of the present invention was used.
A sintered alloy was manufactured under the same conditions except that KF powder or AlF ₃ powder was used instead of the powder, respectively.All the obtained sintered alloys had low strength, toughness, and low wear resistance. there were.

As described above, according to the method of the present invention, Cu-Zn-Al having high strength and high toughness and having poor wear resistance is provided.
-Based sintered alloys can be produced, so that when they are applied, for example, to the production of block rings and bearings, they will exhibit excellent performance over a prolonged period even under severe conditions. Industrially useful effects are brought about.

Claims (1)

(57) [Claims] (1) A Cu-Zn-Al-based alloy powder having a surface oxide layer having an average layer thickness of 0.1 to 1 µm mixed with 0.1 to 3% by weight of a fluoride powder of K and Al in a total amount. A method for producing a compound-dispersed Cu-Zn-Al-based sintered alloy having excellent wear resistance, which comprises mixing, mixing, forming into a green compact, and sintering.