JPS5989736A - Production of al-pb-mg sintered bearing alloy - Google Patents

Abstract

PURPOSE:To disperse uniformly a Pb phase and an Mg phase in an Al matrix phase by compounding Al powder, Mg powder and Pb powder in a specific volumetric ratio, immersing the mixture into a solvent dissolved therein with a binder, and mixing both to prepare a slurry, then evaporating the solvent, molding the mixture to a prescribed shape and sintering the molding. CONSTITUTION:A compsn. contg. 1-80vol% Pb powder and 0.5-5vol% Mg powder is prepd. from Al powder, Pb powder and Mg powder. Such compsn. is immersed in a solvent, for example, toluene, dissolved therein with a binder, for example, paraffin, and is mixed, then the solvent evaporates and a slurry is formed. The mixing is stopped in this state and the remaining solvent is evaporated to form a dry mixture. The dry mixture is sintered after molding to a prescribed shape. A uniformly dispersed Al-Pb-Mg sintered bearing alloy is obtd. by the simple production method referred to as a sluffy mixing method.

Description

[Detailed description of the invention] Regarding the method.

In recent years, AI and -Pb alloys have attracted attention as bearing materials, and various studies have been conducted.

However, the A7-Pb alloy is extremely difficult to manufacture for the following reasons. That is, the maximum solubility of Pb in At is 0.2 weight s C1,5 atoms at a part temperature of 658.5V, and the solubility of Ni in Pb is 0.
At 9% by weight (0.12 atomic%), the collapse is extremely small.

However, the specific gravity of μ is 2.70, while pb is 11.36.
The difference in specific gravity between Pb and U is extremely large.

Therefore, when attempting to manufacture an At-Pb alloy by a casting method, in normal melting, ν Pb separates into two upper and lower phases due to the difference in specific gravity, and when cooled, the AL phase becomes 3 at 658.5 υ.
At 26.8 e, the pb phase solidifies separately.

One way to avoid this situation is to rapidly cool M and pb from a high temperature higher than the temperature of the melt solubility curve (for example, 1080° C. or higher for 20% pb, or 1300 t! or higher for 40% pb).

However, in this method, since At and Pb must be melted at high temperatures, they are highly oxidized in the air and must be produced in an inert atmosphere. Furthermore, in order to manufacture sea bream with a composition containing a large amount of Pb, the melt temperature must be high and the cooling rate must be extremely fast, which means that only small samples can be manufactured. The examples of manufacturing attempted using the melting method so far have had a PB amount of up to 9゜0qb,
Practically, the amount of Pb is up to 6% by weight.

In addition, when manufacturing by powder metallurgy, since the difference in specific gravity between the Pb powder and the Pb powder is large, the two powders tend to separate into two phases during the mixing process, making it difficult to mix them uniformly. Moreover, since the solubility of both powders is extremely low, sintering is also difficult. Up to now, the only experiment to produce At-Pb sintered alloy using powder metallurgy has been the production of At-Pb sintered alloy using At powder, Pb powder, and mechanical alloying method.
-It is extremely difficult to produce a pb sintered alloy.

Moreover, its mechanical strength was also insufficient.

The present invention has been made in view of the above-mentioned circumstances, and its object is to uniformly form a Pb phase and a Mg phase in an At matrix by a simple mixing method called a slurry mixing method.

That is, in the present invention, the At powder, the PB powder, and the Mg powder are mixed in such a manner that the PB powder has a volume of 1°0 to 80.0%, and the -powder has a volume of 0.5 to 80.0%.
When mixed to a volume of 5.0 volume and immersed in a solution in which a binder (e.g., paraffin) has been dissolved in a solvent (e.g., toluene) and stirred, the bath agent gradually evaporates, making it a powder. The viscosity of the injected solution increases and becomes a slurry, and once a suitable viscosity is obtained, the remaining solvent is evaporated and dried, which is then shaped into a predetermined shape and sintered. do.

The method of the present invention will be explained below with reference to the drawings.

First, in the present invention, U powder, Pb powder, and Mg powder are used.
Blend so that the volume is 0%. In this case, the At powder is particularly preferably about 80 to 1500 meshes,
Spray powder or ground powder of 325 to 1500 mesh is used. As the PB powder, a sprayed powder or ground powder of 100 to 350 mesh is used. Mg powder is powder of 60 mesh or less,
Particularly preferably, spray powder or ground powder with a mesh size of 100 to 325 is used.

Next, in the present invention, the mixture is mechanically stirred and mixed by placing the mixture in a container such as a mortar containing a solvent (eg, toluene) in which At powder, PB powder, and binder (eg, paraffin) are dissolved. The types of solvent and binder are that the binder dissolves in the solvent, and that the solvent evaporates during stirring.
Any binder may be used as long as it does not inhibit sintering, but toluene is particularly preferred as the solvent and paraffin as the binder. In this case, an amount of paraffin in toluene of 1 to 10% by weight may be sufficient.

Next, as stirring and mixing are continued, the solvent evaporates and the mixture of powder and solvent increases in viscosity, but when the viscosity becomes just muddy, the stirring is stopped and the volatile content of the remaining solvent is completely removed. Perform a drying process for Sufficiently dried powders are bound together by a binder (e.g. paraffin), and even if some vibration is applied, the bonds between At powder, Pb powder, and stored powder will break and separate. Never.

Next, in the present invention, the mixture obtained by the above mixing method is compression molded and then sintered. Compression molding and sintering here are performed according to a conventional method, for example, compression molding is performed with a pressure of 3 ton lam" or less at a pressure of 500 ~ 1-4 1700 υ, a degree of vacuum of 10 ~ loIT 1 m) ig,
．． Do this for 5 to 2.0 hours.

As a result of this sintering, the active element of Mg destroys the oxide film on the surface of the At powder, active sintering of the red powder occurs, and solid solution of ζ in the At phase increases the strength of the alloy.

Furthermore, the obtained At-Pb-Mg sintered bearing alloy has pb
It has excellent friction and wear characteristics due to the lubricating action of , and has good damping ability (vibration absorption) characteristics.

Examples of the present invention will be described below.

In the following examples, the A7 powder used was a sprayed powder that passed through an 8o mesh, the Pb6 powder used as a sprayed powder that passed through 100 meshes, and the Mg powder used as a sprayed powder that passed through 150 meshes.

Example 1 (1) A homogeneous mixed powder was prepared using the slurry mixing method described above, containing 9 to 17 y% of At powder and 3 volumes of Mg powder, then put into a mold and molded at a molding pressure of 3 tons and 1 cm. Then, in the next section 2, in a vacuum at a freezing temperature of 650 υ (~10 rr + mH, g
) for 1 hour to obtain a sintered body. An example of the sintered body thus obtained (At-16 volume % Pb-3 volume % Mg alloy) is shown in the micrograph of FIG. In addition, the relative density and transverse rupture strength of these sintered bodies are shown in Figures 121 and 13.
It is shown in Figure 1.

(II) At powder 96.7-92.5 volume H, pb
A uniform mixed powder was obtained by the above slurry mixing method with 2.5% by volume of powder and 0.8 to 5% by volume of Mg powder, then put into a mold,
This was molded at a molding pressure of 2 ton jam'' and then fired in a vacuum (~10 mmtig) for 1 hour at a sintering temperature of 650°C to obtain a sintered body.

The measured values of the bending strength and sintered density of this sintered body are also shown in FIG.

Example 2 The specific wear amount of the sintered body shown in Example 1 was measured in a non-lubricated state to examine its wear resistance. The results are shown in FIG. For comparison, lead bronze No. 4 (LBC4),
The specific wear amount was measured for copper lead 3 (KJ3) and white metal (WJI), and the results are also shown in FIG.

In this case, the test machine used was an Okoshi type rapid abrasion tester, and the friction speed was 3 m 62 ml sec, and the final load was 2.i kg 1 blood 1! Closed.

Example 3 The specific wear amount of the sintered body shown in Example 1 was measured in a lubricated state, and its wear resistance was investigated. The results are shown in FIG. In order to compare this, the specific wear amount was measured for the copper-lead third ridge bearing material (KJ3), and the results are also shown in FIG.

The sintered alloy according to the invention is better than copper-lead based alloys over a wide range of pb compositions.

It can be seen from FIGS. 5 and 6 that the sintered alloy according to the present invention has superior friction properties compared to the conventional one.

Example 4 The damping capacity of the sintered body shown in Example 1 was measured, and this was measured in the seventh example.
As shown in the figure. For comparison, lead bronze No. 424 [LB
C4 (No, 44) and At-4,4Cn-0,8S
The damping capacity of the i-0,4Mg sintered bearing material was measured, and this is also shown in FIG. Note that the damping capacity here is a value that does not depend on the strain amplitude, and was measured at a frequency of 300 to 600 C10 by the both-end free lateral vibration method.

It can be seen from FIG. 7 that the damping performance characteristics are better than the conventional ones, and vibrations that are a source of noise in the bearing can be reduced.

As described above, according to the present invention, it is possible to obtain a uniformly dispersed At-Pb-Mg sintered bearing alloy by a simple production method called slurry mixing method, and also the friction and wear characteristics and damping capacity characteristics of the obtained alloy. It has excellent properties and is extremely effective as a bearing material.

[Brief explanation of the drawing]

Figure 1 shows At-16 volume% produced by slurry mixing method.
Microscopic structure photograph of 3 volume% Mg sintered alloy, Figure 2 is a diagram showing the relationship between the amount of Pb and relative density of the sintered body, and Figure 3 is a diagram showing the relationship between Pb1l of the sintered body and transverse rupture strength. , Figure 4 shows Mgi
Figure 5 showing the relationship between the relative density of the sintered body and the transverse rupture strength.
The figure shows the relationship between the amount of pb and the amount of specific wear in a non-lubricated state.
FIG. 6 is a diagram showing the relationship between the amount of pb and specific wear amount in a lubricated state, and FIG. 7 is a diagram showing the relationship between the amount of pb and damping capacity. Ime same Ijiyama hole 1x meeting x Mn sho/, i21 Mu 7 figure

Claims (1)

[Claims] a powder, Pb powder, and Mg powder, Pb powder is 1.0 to 8
The mixture is mixed so that the volume of Mg is 0.0 volume and the Mg is 0.5 to 5.0 volume.Then, this mixture is immersed in a solvent in which a binder is dissolved, and then the mixture and the solvent are mixed. The method is characterized by gradually volatilizing the solvent while mixing, and then, when the mixture becomes a slurry, stopping the mixing and volatilizing the remaining solvent, and then sintering the M powder, Pb powder, and Mg powder into a predetermined shape. AL -Pb -Mg
A method for producing a sintered bearing alloy.