JPH09222125A - Method for manufacturing sintered component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture sintered components having a high quality under a low cost by a method wherein hydro-carbon oil is applied to any one of rust-proof liquid, sizing lubricant and cleaning liquid used in a manufacturing stage. SOLUTION: A cylindrical pressed powder member 10a is attained at a mold forming step 1 and a sintered body 10 is attained at a sintering step 2. The sintered body 10 is immersed into hydrocarbon oil acting as rust-proof liquid so as not to cause rust to be generated at the surface of the sintered body 10 at the rust-proof step 3. A sizing rod 13 is moved up and down within a hole 11 of the sintered body 10 at a sizing step 4 and then porous part or burrs at the inner circumferential surface 12 of the sintered body 10 are compressed again. The rust-proof liquid is utilized as sizing lubricant liquid. At a cleaning step 5, hydrocarbon oil which is the same as the rust-proof liquid is used as the cleaning liquid and then metallic chips generated an the porous portions of the sintered body 10 or generated during sizing operation are removed rather than removing the rust-proof liquid. The sintered body 10 is heated at a drying step 6 so as to evaporate cleaning liquid. Since the hydrocarbon oil has a superior drying characteristic, it is completely evaporated and even if the oil is left as a completed product as it is, no cleaning liquid is left, so that a sintered component having a high quality can be attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a sintered component such as a sintered oil-impregnated bearing. More specifically, the present invention relates to a material technology such as a rust preventive liquid, a sizing lubricating liquid, and a cleaning liquid used in each step performed after molding and sintering the metal powder.

[0002]

2. Description of the Related Art In a method for manufacturing a sintered oil-impregnated bearing, which is a typical sintered part, a molding process, a sintering process, a rust prevention process, a sizing process, a cleaning process, a drying process, and an impregnating process are sequentially performed in this order. It is performed as a process. Of these processes, the cleaning process is the rust preventive liquid used in the rust preventive process, the sizing lubricant used in the sizing process, and the sizing powder and foreign matter remaining in the sintered body after the sizing process. To remove. Therefore, in the cleaning process, ultrasonic cleaning or steam cleaning using methylene chloride or trichlene, which has a strong dissolving power, is conventionally performed so that the rust preventive liquid and the sizing lubricating liquid can be efficiently washed off.

However, methylene chloride, trichlene and the like are also said to have an adverse effect on the human body in the social situation where the use of fluorine-based cleaning agents has been abolished in recent years in order to protect the global environment. And Triclen are in a situation where they will not be able to continue to use them permanently in the future. Therefore, an aqueous cleaning agent or a hydrocarbon cleaning solution has been proposed as an alternative cleaning solution for the halogen-based cleaning solution.

[0004]

However, when the water-based cleaning liquid is used among these alternative cleaning liquids, the water contained in the pores (pores) scattered on the sintered part is not completely removed. Therefore, there is a problem that rust occurs and the quality of the sintered part is significantly deteriorated.

Further, since the water-based cleaning liquid has a lower cleaning ability for the rust preventive liquid and the sizing lubricant liquid than the chlorine-based cleaning agent typified by methylene chloride, the rust preventive liquid and the sizing liquid used before the cleaning process are used. There is also a problem that the lubricating oil for use tends to remain. Although hydrocarbon-based cleaning liquids have a higher degreasing ability than water-based cleaning liquids, compared to chlorine-based cleaning liquids, they have lower cleaning performance for rust preventive liquids and sizing lubricant liquids, so rust preventive liquids and sizing lubricant liquids can be completely removed. It cannot be removed.
Here, if the sizing lubricating liquid or the like remains in the sintered body, the sizing lubricating liquid reacts with the lubricating oil impregnated in the impregnation step with time, and seizure occurs in the sintered oil-impregnated bearing. However, the quality is deteriorated.

When a hydrocarbon-based cleaning liquid is used, the rust preventive liquid and the sizing lubricating liquid can be removed to a considerable level by extending the cleaning time. There is a problem that the cost becomes high.

[0007] In view of the above problems, an object of the present invention is to provide:
It is an object of the present invention to provide a method for producing a sintered part that can produce a high quality sintered part at a low manufacturing cost without using methylene chloride, trichlene, or the like.

[0008]

In order to solve the above-mentioned problems, in the present invention, a molding step of compressing and molding a metal powder into a predetermined shape to obtain a green compact, and the green compact obtained by the molding step. A sinter to obtain a sinter by sintering the sinter, a rust-prevention step of subjecting the sinter obtained by the sinter to a rust-preventive treatment with a rust-preventive solution, and Sintered component manufacturing method including a sizing step of sizing the sintered body with a sizing lubricating liquid adhered to the sintered body, and a cleaning step of cleaning the sintered body after the sizing step with a cleaning liquid. In the above, the hydrocarbon oil is used for any of the rust preventive liquid, the sizing lubricating liquid, and the cleaning liquid.

According to this structure, since the cleaning liquid and the rust preventive liquid and the sizing lubricant liquid are the same composition, it is not necessary to completely remove the rust preventive liquid and the sizing lubricant liquid in the cleaning step. . Therefore, the cleaning time can be shortened without using the halogen-based cleaning agent. Further, even if a rust preventive liquid or a sizing lubricating liquid is mixed in the cleaning liquid, the cleaning liquid hardly changes in composition. Therefore, the cleaning liquid can be repeatedly used by passing through a simple process such as filtration, so that the usage amount can be saved and the waste liquid process is unnecessary.
Therefore, the manufacturing cost of the sintered component can be reduced.
Further, since the hydrocarbon oil has good drying properties, the cleaning liquid does not remain on the sintered parts that have undergone the drying process, so that high quality sintered parts can be manufactured. In particular, when a sintered oil-impregnated bearing or the like is manufactured, since the cleaning liquid does not remain in the sintered parts that have undergone the drying step, the lubricating oil can be well impregnated, and a high-quality sintered oil-impregnated bearing can be manufactured. .

Here, in the sizing step,
It is preferable to use the rust preventive liquid adhering to the sintered body after the rust preventive step as it is as the sizing lubricating liquid.

Further, a drying process may be added after the cleaning process to promote evaporation of the cleaning liquid contained in the sintered component after the cleaning process.

Further, when the method of the present invention is applied to the production of a sintered oil-impregnated bearing, an impregnation step of impregnating the sintered component with lubricating oil may be added after the drying step.

Further, there is an impregnating step of impregnating the sintered part after the cleaning step with a lubricating oil, and the same hydrocarbon oil as the lubricating oil is added to the rust preventive liquid, the sizing lubricant liquid,
It may also be used as the cleaning liquid. With this configuration, the impregnating step can be performed on the sintered component after the cleaning step as it is, and the drying step performed after the cleaning step can be omitted.

On the other hand, in the present invention, as the hydrocarbon oil, any one of paraffin hydrocarbon oil, isoparaffin hydrocarbon oil, and naphthene hydrocarbon oil, or a composition of two or more thereof is used. Can be used.

[0015]

Embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1) FIG. 1 is a process diagram showing a method for manufacturing a sintered oil-impregnated bearing (sintered component) of this embodiment. FIG.
It is explanatory drawing which shows the process of sizing the sintered oil-impregnated bearing of this example.

As can be seen from FIG. 1, also in the method of manufacturing the sintered oil-impregnated bearing of the present example, the molding step 1, the sintering step 2, the rust preventive step 3, the sizing step 4, and the cleaning step 5 are performed as in the conventional manufacturing method. The drying step 6 and the impregnation step 7 are performed in this order.

First, in the molding step 1, for example, the coating amount of copper is 40% by weight, 80 parts by weight of copper-coated iron powder having a particle size distribution of 200 mesh or less, and the graphite (carbon) content is 1.3%. , Copper with a particle size distribution of 200 mesh or less
20 parts by weight of graphite composite powder, and zinc stearate as a lubricant between the pressing die and the powder during molding 0.3 to
0.5 parts by weight, and then mixed and stirred, and then molded under a pressure of 1 ton / cm ² , and as shown in FIG. 2, the outer diameter is 7.02 mmφ, the inner diameter is 3.54 mmφ,
A cylindrical green compact 10a having a height of 4.0 mm is obtained.

Next, in a sintering step 2, the green compact 10a is preheated and then sintered in an ammonia decomposition gas for 30 minutes under a temperature condition of 750 to 800 ° C. to obtain a sintered body 10.

Next, in the rust-prevention step 3, the rust-prevention treatment is applied to the sintered body 10 after the sintering step 2 until the final step, so that rust does not occur on the metal surface. In this anticorrosion treatment, hydrocarbon oil is used as an anticorrosion liquid, and a large number of sintered bodies 1 housed in a cleaning basket or the like are contained in the anticorrosion liquid (hydrocarbon oil).
Soak 0 together.

Next, in the sizing step 4, the rust prevention step 3
After that, the shape and surface condition of the sintered body 10 are adjusted. In this step, as shown in FIG. 2, the hole 1 of the cylindrical sintered body 10 is
A sizing rod 13 having a diameter substantially the same as the inner diameter of the sintered body 10 is passed through the upper and lower portions of the sintered body 1, and small irregularities such as pores and burrs scattered on the inner peripheral surface 12 of the sintered body 10 are recompressed by the sizing rod 13. As a result, the sintered body 10 has improved surface roughness and finer porous structure. In this sizing step 4, a sizing lubricating liquid is usually attached to the sintered body 10 for the purpose of reducing the friction coefficient between the sintered body 10 and the sizing rod 13. The rust preventive liquid (hydrocarbon oil) used in step 3 adheres to the surface of the sintered body 10 and is used as it is as a lubricating liquid for sizing without being dried.

Next, the cleaning step 5 is performed. This washing step 5
Conventionally, the purpose was to remove the rust preventive liquid and the lubricating liquid for sizing, but in this example, a hydrocarbon oil is used as the cleaning liquid as with the rust preventive liquid (lubricating liquid for sizing). Therefore, the purpose is not to remove the rust preventive liquid (lubricant for sizing), but rather to remove the metal powder in the pores of the sintered body 10 and to remove the metal powder generated during sizing. To do. Here, if the rust preventive liquid (lubricating liquid for sizing) and the cleaning liquid are exactly the same hydrocarbon oil, the composition of the cleaning liquid will not change at all, but if they match in terms of hydrocarbon oil, the number of carbon May be different.

Next, in the drying step 6, the sintered body 10 after the cleaning step 5 is heated to evaporate the cleaning liquid (hydrocarbon oil) adhering to the sintered body 10. In this drying step 6,
To prevent the oxidation of copper, which is the raw material of the sintered body 10, 8
It is performed under a temperature condition of 0 ° C or lower. Here, the hydrocarbon oil is
Since the drying property is good, it completely evaporates from the surface of the sintered body 10. Therefore, even when the sintered body 10 that has undergone the drying step 6 is used as it is as a finished product (sintered component), since the cleaning liquid does not remain in the sintered body 10, a high quality sintered component can be manufactured.

In this example, since a sintered oil-impregnated bearing is manufactured as a sintered part, the impregnation step 7 is performed after the drying step 6. In this impregnation step 7, the sintered body 1 that has completed the drying step 6
0 is impregnated with mineral oil (paraffin hydrocarbon oil, naphthene hydrocarbon oil, etc.) as a lubricating oil. By this impregnation step 7, the sintered body 10 becomes a sintered oil-impregnated bearing. Here, the lubricating oil may be impregnated with a synthetic oil (such as a polyolefin-based hydrocarbon oil) instead of the mineral oil.

As described above, in the method for manufacturing a sintered oil-impregnated bearing (sintered component) of this example, the rust preventive liquid used in the rust preventive step 3
Since both the sizing lubricating liquid used in sizing step 4 and the cleaning liquid used in cleaning step 5 are hydrocarbon oils, it is not necessary to completely wash out the rust preventive liquid and the sizing lubricating liquid in cleaning step 5. It suffices to remove the metal powder present in the porous body of the sintered body 10 and the foreign matter such as the metal powder generated in the sizing step. Therefore,
The time spent in the cleaning step 5 can be shortened and the productivity is improved.

Further, since hydrocarbon oil is used as the rust preventive liquid, the sizing lubricant liquid and the cleaning liquid, even if the rust preventive liquid or the sizing lubricant liquid is mixed in the cleaning liquid in the cleaning step 5, No change in composition occurs in the cleaning liquid. Therefore,
Since the cleaning liquid can be used repeatedly only by removing the metal powder or the like from the cleaning liquid by filtration, almost no waste liquid is produced from the cleaning step 5. Therefore, the amount of the cleaning liquid used can be saved, and since the treatment of the waste liquid is unnecessary, the manufacturing cost of the sintered parts such as the sintered oil-impregnated bearing can be reduced.

Further, since only the hydrocarbon oil having good drying property is attached to the sintered body 10 after the cleaning step 5,
There is no residual cleaning liquid in the sintered body 10 that has completed the drying step 6, and the lubricating oil is satisfactorily impregnated in the sintered body 10 in the impregnation step 7, so that a sintered component of excellent quality can be manufactured.

Moreover, in the manufacturing method of this example, the rust prevention step 3
Since the rust-preventive liquid adhering to the sintered body 10 which has been subjected to the above step is used as it is as the sizing lubricating liquid, it is not necessary to separately prepare the sizing lubricating liquid. Therefore, the manufacturing cost is reduced, and the sintered part can be manufactured at a lower cost.

Further, hydrocarbon oil is kind to the global environment,
There is also an advantage that the effect on the human body is relatively small.

(Embodiment 2) FIG. 3 is a process chart showing a method for manufacturing a sintered oil-impregnated bearing (sintered component) of this embodiment. The basic steps of the method for manufacturing a sintered part of the present example are the same as the manufacturing steps of Example 1 except that the drying step is omitted. Therefore, common steps are given the same reference numerals. The detailed description thereof will be omitted.

As shown in FIG. 3, even in the manufacturing process of the sintered part of this example, the molding process 1, the sintering process 2, the rust prevention process 3, the sizing process 4, the cleaning process 5, and the impregnation process 7 are performed in this order. Done in.

In the forming step 1, first, a green compact 10a is prepared, and this green compact 10a is made into a sintered body 10 in the next sintering step 2.

Next, in the rust preventive step 3, the sintered body 10 after the sintering step 2 is subjected to a rust preventive treatment with a rust preventive liquid. Here, hydrocarbon oil is used as the rust preventive liquid.

Next, in the sizing step 4, as described in Embodiment 1 with reference to FIG.
3 and using the rust preventive liquid adhering to the surface of the sintered body 10 as it is as the sizing lubricant,
Sizing is performed on the sintered body 10.

Next, a cleaning step 5 is performed. This washing step 5
As the cleaning liquid used in, a hydrocarbon oil having the same composition as the lubricating oil used in the impregnation step 7 to be performed next is used. That is,
When the lubricating liquid used in the impregnation step 7 is a mineral oil composed of paraffinic hydrocarbon oil, the cleaning liquid used in the cleaning step 5 is a mineral oil composed of paraffinic hydrocarbon oil. If hydrocarbon oils having the same composition are used for the cleaning liquid and the anticorrosive liquid (lubricating liquid for sizing), the cleaning process 5
Even if the rust preventive liquid remains in the sintered body 10 after the above, the lubricating liquid can be impregnated into the sintered body 10 in the next impregnation step 7 as it is.

Next, the impregnation step 7 is performed. In this example, unlike Example 1, the drying step 6 is not performed after the cleaning step 5, so that when the impregnation step 7 is performed, the cleaning liquid used in the cleaning step 5 adheres to the sintered body 10. Since this cleaning liquid has the same composition as the lubricating oil used in the impregnation step 7, the lubricating oil is impregnated as it is. By this impregnation step 7, the sintered body 10 becomes a sintered oil-impregnated bearing.

As described above, in this example, the rust preventive liquid used in the rust preventive process 3, the sizing lubricating liquid used in the sizing process 4, the cleaning liquid used in the cleaning process 5, and the lubrication used in the impregnating process 7 are used. Since both of the liquids are hydrocarbon oils and the cleaning liquid and the lubricating oil are hydrocarbon oils having the same composition, even if the cleaning liquid is attached to the sintered body 10 after the cleaning step 5, the cleaning liquid is evaporated. However, the impregnation step 7 can be performed as it is without removal. Therefore, since the drying step 6 can be omitted from the manufacturing method described in the first embodiment, in addition to the effect similar to that of the first embodiment, the amount of the drying step 6 is omitted, the sintering such as a sintered oil-impregnated bearing is performed. The manufacturing cost of parts can be reduced.

(Other Examples) As the hydrocarbon oil, any one of paraffin hydrocarbon oil, isoparaffin hydrocarbon oil, and naphthene hydrocarbon oil is used.
The seeds may be used alone, or two or more kinds of these hydrocarbon oils may be mixed and used.

Further, in the embodiment, the method for manufacturing the sintered oil-impregnated bearing has been described, but the present invention can be applied to other sintered parts.

[0040]

As described above, in the method for manufacturing a sintered part according to the present invention, since hydrocarbon oil is used as the rust preventive liquid, the sizing lubricant liquid and the cleaning liquid, the cleaning liquid and the rust preventive liquid are used. As long as the liquid and the sizing lubricant are of the same composition, it is not necessary to completely remove the rust preventive liquid and the sizing lubricant in the cleaning step. Therefore, the cleaning time can be shortened without using the halogen-based cleaning agent. Further, even if a rust preventive liquid or a sizing lubricating liquid is mixed in the cleaning liquid, the cleaning liquid hardly changes in composition. Therefore, the cleaning liquid can be repeatedly used by passing through a simple process such as filtration, so that the usage amount can be saved and the waste liquid process is unnecessary. Therefore, the manufacturing cost of the sintered component can be reduced. Further, since the hydrocarbon oil has good drying properties, the cleaning liquid does not remain on the sintered parts that have undergone the drying process, so that high quality sintered parts can be manufactured. In particular, when a sintered oil-impregnated bearing or the like is manufactured, since the cleaning liquid does not remain in the sintered parts that have undergone the drying step, the lubricating oil can be well impregnated, and a high-quality sintered oil-impregnated bearing can be manufactured. . Moreover, since hydrocarbon oil is used, there are advantages that it is friendly to the global environment and has a relatively small effect on the human body.

Further, when a hydrocarbon oil having the same composition is used as the cleaning liquid and the lubricating oil, the impregnating step can be directly performed on the sintered parts after the cleaning step, and the drying performed after the cleaning step can be performed. The process can be omitted. Therefore, the manufacturing cost of the sintered oil-impregnated bearing can be further reduced.

[Brief description of drawings]

FIG. 1 is a process chart showing a method for manufacturing a sintered part according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an outline of a sizing step of the manufacturing method shown in FIG.

FIG. 3 is a process drawing showing a method of manufacturing a sintered part according to a second embodiment of the present invention.

[Explanation of symbols]

 1 Molding process 2 Sintering process 3 Rust prevention process 4 Sizing process 5 Cleaning process 6 Drying process 7 Impregnation process 10 Sintered body 10a Green compact 11 Hole 12 Inner peripheral surface 13 Sizing bar

Claims (7)

[Claims] 1. A molding step of compression-molding metal powder into a predetermined shape to obtain a green compact, and a sintering step of sintering the green compact obtained by the molding step to obtain a sintered body. A rust-preventing step of subjecting the sintered body obtained by the sintering step to a rust-preventing treatment with a rust-preventing solution, and the sizing lubricating liquid being adhered to the sintered body after the rust-preventing step. In a method for manufacturing a sintered component, which comprises a sizing step of sizing a bonded body, and a cleaning step of cleaning the sintered body after the sizing step with a cleaning liquid, the rust preventive liquid, the sizing lubricating liquid, and the A method for producing a sintered part, characterized in that a hydrocarbon oil is used as any of the cleaning liquids. 2. The sintering according to claim 1, wherein, in the sizing step, the rust preventive liquid adhering to the sintered body that has been subjected to the rust preventive step is used as it is as the sizing lubricating liquid. Manufacturing method of parts. 3. The method of manufacturing a sintered part according to claim 1, further comprising a drying step of evaporating the cleaning liquid adhering to the sintered part that has completed the cleaning step. 4. The method of manufacturing a sintered component according to claim 3, further comprising an impregnation step of impregnating the sintered component that has finished the drying step with a lubricating oil. 5. The method according to claim 1 or 2, further comprising an impregnation step of impregnating the sintered component after the cleaning step with a lubricating oil, wherein the same hydrocarbon oil as the lubricating oil is added to the rust preventive liquid, the A method for producing a sintered part, which comprises using a sizing lubricating liquid and the cleaning liquid. 6. The method for manufacturing a sintered component according to claim 4, wherein the sintered component is a sintered oil-impregnated bearing. 7. The method according to claim 1, wherein
The hydrocarbon oil is a composition of any one or two or more of paraffinic hydrocarbon oil, isoparaffinic hydrocarbon oil, and naphthenic hydrocarbon oil. Production method.