JPH036342A - Sintered alloy and its production - Google Patents

Abstract

PURPOSE:To easily and accurately produce a sintered alloy having stable strength, corrosion resistance, and compatibility to mating members by mixing bronze powder and brass powder having respectively specified compositions into a specific ratio and subjecting the resulting powder mixture to compacting and sintering. CONSTITUTION:Brass powder consisting of, by weight, 5-40% Zn and the balance essentially Cu is mixed with bronze powder consisting of 2-12% Sn and the balance essentially Cu by 25-400 pts.wt. based on 100 pts.wt. of the bronze powder. Further, a solid lubricant of graphite or MoS2 is mixed with the above by 0.6-25 pts.wt., if necessary. The resulting powdery raw material is compacted and sintered. By this method, a sintered alloy consisting of 1.5-12% Sn, 8-40% Zn, and the balance essentially Cu and having 15-25vol.% porosity or a sintered alloy consisting of 1.5-12% Sn, 8-40% Zn, 0.6-5% solid lubricant, and the balance essentially Cu and having 18-22vol.% porosity can be obtained. These sintered alloys have stable strength and corrosion resistance and also have superior compatibility to mating members.

Description

[Detailed Description of the Invention] "Object of the Invention" The present invention relates to a method for producing a sintered alloy, and provides a relatively simple and accurate method for producing a sintered alloy that has stable strength, corrosion resistance, and conformability to a mating member. This is what we are trying to provide.

(Industrial application field) Manufacturing technology for sintered alloys that have excellent corrosion resistance and strength, as well as appropriate compatibility with mating parts.

(Prior art) Various sintered alloys have been proposed in the past, but iron-based alloys have excellent strength but are inferior in compatibility with mating parts, while copper-based alloys have poor compatibility with mating parts. Even if the compatibility is good, the strength is insufficient.

Therefore, techniques such as Japanese Patent Publication No. 3B-22103 have been published in order to provide all of the advantages of these sintered alloys. That is, a powder compact made of copper powder and tin powder is sintered in zinc vapor to form a ternary alloy of Cu-Sn-Zn on the surface, which makes it difficult to form a mating member as a copper-based sintered alloy. It is possible to provide a sintered alloy product that not only has conformability but also has improved corrosion resistance and strength, and is therefore suitable for use in bearings and the like.

(Problem to be solved by the invention) As mentioned above, it can be said that the Cu-Sn-Zn ternary alloy can improve corrosion resistance and strength, but only on the surface, and the entire alloy body does not have such ternary alloys. Since it is not made of an alloy, it is not possible to obtain a product with stable and uniform properties.

In addition, it is necessary to generate and permeate Zn% gas during sintering, so 7. It is not easy to appropriately control the concentration of Zn vapor, and the quality characteristics of products vary depending on how the concentration of Zn vapor is managed.

Furthermore, even if the Zn vapor concentration is properly controlled, the Zn content basically seeps in from the outside, so the alloy composition becomes non-uniform and unstable.

Furthermore, since the green compact and the zinc vapor generation source are handled separately, workability is poor, and the manufacturing process, especially the sintering process, is complicated.
Loss due to Zn is also unavoidable and causes cost increase, and also from this point of view, stability is lacking.

"Structure of the invention" (Means for solving the problem) 1. Sn: 1.5-12wt%, Zn:
A sintered alloy characterized by containing 8 to 40 wt% of Cu, the remainder being substantially Cu, and having a porosity of 15 to 25 VOI%.

2. Sn: 1.5~l 2wt%, Zn:
It contains 8 to 40 wt%, and 0.6 to 5 wt% of graphite and other solid lubricants, with the remainder being substantially C.
A sintered alloy having a porosity of 18 to 22 vol%.

3. Contains Sn: 2 to 12 wt%, the remainder being substantially Cu
Zn: 5-40iv for 100 parts of bronze powder
t% of brass powder with the remainder being substantially Cu.
A method for producing a sintered alloy, which comprises using raw material powders mixed at a ratio of 40 Qwt parts, compacting the raw material powders, and then sintering the raw material powders.

4. Contains Sn: 2 to 12 wt%, the remainder being substantially Cu
Zn: 5-40wt for 100 parts of bronze powder
% and the remainder is substantially Cu.
0.00 wt part and a solid lubricant that is either graphite or molybdenum disulfide or both at a ratio of 0.6 to 25 wt part is used, and the raw material powder is compacted and then sintered. A method for producing a sintered alloy characterized by:

(Example) To explain the specific embodiment of the present invention as described above, in the present invention, a mixture of bronze alloy and brass alloy powder is compacted and sintered to form a sintered alloy. Bronze alloys generally contain Sn from 2 to 2.
Brass alloys are generally Cu-based alloys containing 5 to 40% Zn, while the balance is Cu.
These powders are mixed, graphite, molybdenum disulfide, or lead powder is added as appropriate, and the mixture is compacted and then sintered.

The above-mentioned bronze powder and brass powder are generally both
It can be selected as appropriate within the range of 80 wt%, so that at least Sn as a ternary alloy of Cu-Sn-Zn
is 0.4 to 9.6 wt%, and Zn is 1.0 to 32.0 wt%.
% of Cu, and the balance is Cu.

Further, it is preferable to mix the solid lubricant powder such as graphite in an amount of 5 wt % or less in order to obtain a bearing or the like.

Products that have been compacted and sintered are sized and made into products with precise shapes and dimensions, but the porosity of such products is generally 15 to 25%, especially in the case of bearing materials. is 18-22%. In any of the alloys of the present invention, which mainly consist of Cu, compaction is easy,
Even if it contains Zn, it is contained as an alloy, so the loss due to zinc diffusion during sintering is very small, and a stable quality product with a uniform composition distribution can be appropriately obtained. It is possible to simplify the manufacturing process and obtain the desired product at low cost.

A specific manufacturing example of the product according to the present invention will be described below.

Production Example I Bronze powder with Cu: 91%, Sn 9%, particle size 100 mesh, Cu: 60%, Zn 40%,
- Using 100 mesoyu brass powder, 5Qwt bronze powder
A raw material powder containing 49 wt % of brass powder and 1 wt % of graphite was prepared.

The graphite used had a particle size of -250 mS, that is, the particle size was different from that of the alloy powder, so that a uniform mixed state could be formed and maintained even due to the difference in specific gravity.

The raw material powder obtained as described above was sequentially charged into a mold and compacted into a cylindrical bearing with an outer diameter of 12 m1, an inner diameter of 61 mm, and a height of 10 mm. A sintering process was performed for 20 minutes in a decomposed gas atmosphere, and then sizing was performed to obtain a bearing body with a porosity of 19%.

Of the approximately 100 bearing bodies obtained as described above, 20 test specimens were randomly selected, their radial crushing strength and friction coefficient were measured, and the average value was determined. kgf/w2, and the friction coefficient is 0.0
45, and it was confirmed that the bearing was extremely stable and good in terms of quality.

Production Example 2 Using the same bronze powder and brass powder as in Production Example 1, the mixture ratios were varied as shown in Table 1 below, and the powder molding, sintering, and sizing processes were prepared. was carried out in the same manner. The measurement results regarding the quality of each product obtained are also shown in Table 1.

In other words, it was confirmed that all of the materials in Table 1 and Table 2 had approximately favorable characteristics as bearing materials, and each of the randomly selected 10
The variation range for each sample is approximately 4 in the radial crushing strength.
kgf/salt*2, the friction coefficient was 0.01, and the quality was stable.

Production Example 3 Various sintered alloys were produced using bronze powders and brass powders with different compositions. That is, the compositions of the bronze powder and brass powder employed were as shown in Table 2 below.

However, due to the mixing ratio of the raw material powder that is made by combining the alloy powders of ① to [phase], the powder compaction,
The characteristics of each sintered product were as shown in Table 3 below.

0 Third This invention enables the simple and accurate production of a sintered alloy having excellent surface conformability, and is industrially highly effective.

That is, it was confirmed that all of them had substantially favorable bearing performance and were stable sintered alloys.

"Effect of the invention"

Claims (4)

[Claims] 1. Sn: 1.5-12wt%, Zn: 8-40wt%
, the remainder is substantially Cu, and the porosity is 15-15.
A sintered alloy characterized by having a content of 25 vol%. 2. Sn: 1.5-12wt%, Zn: 8-40wt%
Contains graphite and other solid lubricants from 0.6 to
5 wt%, the remainder being substantially Cu, and having a porosity of 18 to 22 vol%. 3. Contains Sn: 2 to 12 wt%, the remainder being substantially Cu
Zn: 5 to 40 wt for 100 wt part of bronze powder.
% and the remainder is substantially Cu.
A method for producing a sintered alloy, which comprises using raw material powders mixed at a ratio of 0.00 parts by weight, compacting the raw material powders, and then sintering the raw material powders. 4. Contains Sn: 2 to 12 wt%, the remainder being substantially Cu
Zn: 5 to 40 wt for 100 wt part of bronze powder.
% and the remainder is substantially Cu.
Using a raw material powder in which 0.00 wt part and 0.6 to 25 w part of a solid lubricant of graphite or molybdenum disulfide or both are mixed in a ratio of 0.6 to 25 w part, the raw material powder is compacted and then sintered. A method for producing a sintered alloy characterized by the following.