JPH07242986A - Production of oilless composite alloy - Google Patents

Abstract

PURPOSE:To provide an oilless composite alloy having the characteristic same as or higher than that of the conventional complex sliding member integrated with a base alloy and solid lubricant and to realize the improvement of a product so as to have high wear resistance and lubricity, etc., and the saving of man-hour, in a casting of alloy cast iron or copper alloy casting, etc., used for the sliding member. CONSTITUTION:In the production of the oilless composite alloy containing the alloy cast iron base stock or the copper alloy base stock as the base alloy, after charging the suitable quantity of a graphite base inoculant 1 into a molten metal pool part 3 or a mold 2, the molten metal 4 is cast and the inoculating treatment is applied and the graphite is dispersed and crystallized as the solid lubricating material. The graphite base inoculant 1 is the one prepared in powdery or granular state with few micron-few mm diameter and its adding ratio is desirable to be 2.5-5.0vol% to the base alloy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an oil-free composite alloy including an inoculation step during casting, and more specifically, an oilless wear plate and die face for a press machine, a cylinder liner for an engine, a bearing, etc. The present invention relates to a method for producing an oil-free composite alloy, which is provided as a sliding member and has properties comparable or superior to those of a conventional composite sliding member in which a base alloy and a solid lubricant are integrated.

[0002]

2. Description of the Related Art Conventionally, in sliding members of automobiles and machine tools, the sliding surface is subjected to surface treatment for enhancing wear resistance and lubricity, and a solid lubricant is embedded in a base material subjected to drilling. While the technology is known, it is known to provide alloys such as cast iron, copper-based alloys or composite alloys as wear-resistant alloys used under severe sliding conditions as represented by bearing alloys. .

Here, as a sliding member of a press machine or the like,
A solid lubricating material is embedded in the hole of cast iron, aluminum bronze alloy steel, etc. to form an integrated body (hereinafter, this type is referred to as a composite sliding member). There has been an attempt to improve lubricity and mechanical strength by forming an alloy layer on the. (See, for example, JP-A-1-182622.)

Therefore, when evaluation is made by forming a lubricating film on the friction surface by coating with a solid lubricant or embedding a molded solid lubricant, for example, in the case where a die-cast cast iron material is used as a base material and graphite is embedded in the base material. , The material design including the arrangement of the molded solid lubricant depending on the usage conditions (mate, material, surface treatment, hardness; load; sliding direction, sliding speed; atmospheric temperature; use of chemicals, etc.) , And man-hours such as embedding were required.

Most of the conventional techniques require machining or fixing of the solid lubricant to the substrate as described above, which is accompanied by processing cost and use temperature limitation.

[0006] In view of these problems, there have been attempts to solve the above problems by integrating the substrate with the solid lubricant in the casting process. For example, JP-A-3
In -128161, the solid lubricant is fitted and fixed in the fitting hole of the vanishing model by the full molding method and then poured, and the solid lubricant is partially embedded and integrated in the metal base. A method of manufacturing the composite sliding member is disclosed.

However, the above-mentioned full molding method has a drawback that the casting surface is apt to be rough. There is also a problem that the base alloy forming the boundary with the solid lubricant is easily damaged during use.

As described above, regarding the wear resistance and the self-lubricating property under the use conditions, individual technical problems including the mass effect still remain, and there is a demand for the product cost as a consumable member.

Therefore, the position of the present invention related to the above-mentioned field of application is an oil-free composite alloy, in which graphite is dispersed and crystallized in the base alloy by the molten metal treatment during casting to improve the structure and self-lubrication. It is intended to improve the wear resistance and wear resistance.

[0010] In the molten metal treatment, it has been secretly known for a long time that the addition (inoculation) of substances in the molten metal may cause physicochemical changes beyond the influence of the alloying effect as an alloying (inoculation) agent. There is a historical background that the inoculation treatment has been performed, and today, as typical inoculation methods, ladle inoculation, hot water inoculation, ladle inoculation, hot pool inoculation and in-mold inoculation are known. Thus, the known inoculation treatments are generally the subject of alloyed cast irons, the general purpose effect being to promote iron-graphite solidification and, phenomenologically, improve the graphite crystallization state.

Factors affecting the inoculation effect are considered to be the ingredients of the original hot water, the elapsed time after inoculation and the inoculant, and Si-based inoculants and graphite-based inoculants are known as inoculants for cast iron. There is.

As a cast iron material that has been subjected to this treatment, spheroidized graphite cast iron, that is, cast iron in which graphite is crystallized into spherical particles in the as-cast state, is well known, and cerium (Ce), magnesium ( Mg), calcium (C
a) and the like are effective elements.

[0013]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above circumstances, and in a cast product such as alloy cast iron or copper alloy cast product used as a sliding member, graphite is dispersed in a base alloy. -It is an object of the present invention to provide a method for producing an oil-free composite alloy that can be crystallized to improve products such as wear resistance and high lubricity and reduce man-hours.

[0014]

In order to achieve the above object, the present invention is a method for producing an oil-free composite alloy having a cast iron alloy material or a copper alloy material as a base alloy, and an appropriate amount in a pool or a mold. Of the graphite-based inoculant, the molten metal is cast, the inoculation treatment is performed, and the graphite is dispersed and crystallized as a solid lubricant.

Here, the graphite-based inoculant is prepared in the form of powder or particles having a diameter of several microns to several millimeters, and the addition ratio thereof may be 2.5 to 5.0% by volume with respect to the base alloy.

In a preferred embodiment, a graphite-based inoculant is inoculated in a hot water pool or in a mold to cast a melt of an alloy cast iron material or a copper alloy material to disperse and crystallize graphite in the base alloy, An alloy phase and a graphite phase (solid lubricant) are exhibited, and an iron-free or copper-based oil-free composite alloy is obtained by the same method.

The supply destination of the members is mainly an oilless wear plate of a press machine and the like, and also a press die face, an engine cylinder liner and various bearings. In this case, it is preferable that the graphite distribution during solidification of the molten metal be crystallized to have a size of 15 μ to 150 μ per 1 mm square visual field, and
It is assumed that 5 to 10 pieces are scattered. The shape and the like may be machined as necessary.

[0018]

[Function] The charged graphite is mixed with the molten metal, is inoculated, and is dispersed and crystallized in the base alloy at the time of solidification of the molten metal to form a two-phase structure, so that the composite alloy is modified.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION An optimum embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a process explanatory view according to the method for producing an oil-free composite alloy of the present invention. Here, 1 is a graphite-based inoculant, 2 is a mold, 3 is a pool, and 4 is a molten metal (alloy cast iron material or copper alloy cast material).

In the figure, the graphite-based inoculant (1) is placed in both the basin (3) and the mold (2). This is for the purpose of explanation only in one figure. At least one of them may be selected as one step of the method of the present invention. Two positions in the mold (2) may be selected or used in combination, but when inoculating into the product mold, it is preferable to perform coating on the inner surface of the mold as well.

A casting method for including the inoculation step is a so-called in-mold inoculation method [hereinafter referred to as "pouring inoculation (method)" in which a molten metal is cast by introducing a graphite-based inoculant into a sprue-type basin or mold. Alternatively, it includes in-mold inoculation (method) and is referred to as in-mold inoculation (method). ], The mold is a wooden mold.

Therefore, the graphite-based inoculant (1) is added to the mold (2
Or 3) Inoculate and melt alloy cast iron [or molten copper alloy]
(4) is cast, allowed to cool, and then taken out.

In carrying out the present invention, as long as it does not deviate from the gist of the present invention, the casting method and the modification of the die technology and the like are free and may be made appropriately. For example, a feeder is provided from a plurality of places, a plurality of inoculation places is provided, and a die technique therefor. (These figures are omitted.)

Since graphite is dispersed and crystallized as a solid lubricant at the time of solidification of the molten metal, the physical properties of the composite alloy are comparable to those of the composite sliding member in which the base alloy and the solid lubricant are integrated or the friction characteristics are more than that. Can be earned as.

Here, the graphite-based inoculant (1) is prepared in the form of powder or granules having a diameter of several microns to several millimeters, and it is preferable to crystallize it into a size of 15 μ to 150 μ. This graphite-based inoculant (1) may be a commercially available product, and may be a cast mass of various weights regardless of the above grain size, but from the viewpoint of cost, a graphite carburizing agent such as electrode scrap is also preferable. . The addition ratio of the graphite-based inoculant (1) is
In the range of 2.5 to 5.0% by volume with respect to the base alloy, it is preferably about 3.0% by volume in view of good results.

The composition of the base alloy is roughly divided into alloy cast iron material and copper alloy material, but the manufacturing process (processing conditions) is the same. That is, a graphite-based inoculant was inoculated into the mold to cast a molten alloy of cast iron material or copper alloy material to disperse and crystallize graphite in the base alloy, presenting a base alloy phase and a graphite phase (solid lubricant). It is possible to obtain an iron-free or copper-based oil-free composite alloy.

The alloy cast iron material constituting the base alloy (phase) of the oil-free composite alloy of the present invention is, for example, FC2.
(Normal) cast iron products such as 50 (JIS) are the main consideration range, and materials of such a component system will be selected. As a matter of course, cast steel products are out of the range, but addition of alloying elements such as phosphorus (P) is allowed if necessary. On the other hand, as a copper alloy material, a copper alloy casting such as BC6 (JIS) is mainly considered.

Since the method of the present invention does not rely on the full molding method, the casting surface is good, and therefore the finishing allowance can be reduced. In the practical application test, it was set to 9 mm, but it was evaluated that about 5 mm or less is sufficient.

The friction characteristics of the product of the present invention at the time of 100,000 strokes were evaluated by the wear amount [mm] VS. load [N / cm ² ] and found to be 0 compared with the conventional product (composite sliding member). ~ 50% reduction (compared to in-house) A reduction in wear was confirmed. (This data plot is omitted.) Further, in the conventional product, although the sliding surface of the base body was partially scratched, the member surface (sliding surface) of the product of the present invention had no abnormality. No seizure was observed.

The member supply destination of the product of the present invention is typically an oilless wear plate such as a press machine. In this case,
Graphite distribution during solidification of molten metal is preferably 15 per millimeter square field of view
It is assumed that crystals were crystallized to a size of μ to 150 μ and that 5 to 10 were scattered. The shape and the like may be machined as necessary.

The present invention is also to provide an alloy material, and can be used in various applications such as a press die face, an engine cylinder liner and various bearings which require wear resistance and high lubricity. .

An enlarged schematic view of the surface of the oil-free composite alloy member is shown in FIG. 2, in which 5 is a base alloy (phase) [FC250] and 6 is a graphite (phase). ). In the enlarged schematic diagram shown in the figure, the product of one embodiment is sampled at 100 mm square, and the 1 mm square field of view at one of the 9 measurement points (3 points in the vertical direction and 3 points in the horizontal direction) on the material surface is multiplied by 100 times. It is a sketch from the enlarged optical micrograph.

When the crystallized graphite (6) was evaluated by the total number of surface distributions at the above 9 points, it was about 80 in the case of inoculation in a hot water pool and about 100 in the case of in-mold inoculation. And
All products met the desired frictional properties.

[0034]

EFFECTS OF THE INVENTION The present invention has the above-mentioned constitution. According to the present invention, when a molten metal is solidified, graphite, which is a solid lubricant, crystallizes out and disperses almost uniformly in the base alloy. It is possible to obtain a property comparable to that of a conventional composite sliding member in which and are integrated, or a property higher than that with friction characteristics as a physical property of the composite alloy.

Further, the alloy material itself is used as a sliding member (cast product).
Since it can be provided as, it is possible to reduce the number of man-hours such as secondary processing, and it is possible to mass produce.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of processing steps of an embodiment of the present invention.

FIG. 2 is an enlarged schematic view of a member surface for explaining the structure of the oil-free composite alloy of the present invention.

[Explanation of symbols]

 1 Graphite Inoculant 2 Mold 3 Hot Water Pool 4 Molten Metal (Alloy Cast Iron Material or Copper Alloy Material) 5 Base Alloy (Phase) 6 Graphite (Phase)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display area F16C 33/14 6814-3J

Claims (5)

[Claims] 1. A method for producing an oil-free composite alloy comprising a cast iron alloy material or a copper alloy material as a base alloy in the production of a cast product which is used as a sliding member and exhibits wear resistance and high lubricity, the method comprising: A method for producing an oil-free composite alloy, which comprises pouring an appropriate amount of a graphite-based inoculant into a puddle or a mold to cast a molten metal, performing an inoculation treatment, and dispersing / crystallizing graphite as a solid lubricant. 2. The graphite-based inoculant is prepared in the form of powder or granules having a diameter of several microns to several millimeters, and the addition ratio thereof is 2.5 to 5.0 volume% with respect to the base alloy. Manufacturing method of oil-free composite alloy. 3. A graphite-based inoculant is inoculated to cast a melt of an alloy cast iron material to disperse and crystallize graphite in a base alloy so as to exhibit an iron-based alloy phase and a graphite phase. A method for producing the oil-free composite alloy described. 4. A graphite-based inoculant is inoculated to cast a molten copper alloy material, and graphite is dispersed and crystallized in the base alloy so as to exhibit a copper-based alloy phase and a graphite phase. A method for producing the oil-free composite alloy described. 5. A member supply destination is an oilless wear plate and die face of a press or the like, a cylinder liner and a bearing of an engine, and a graphite distribution during solidification of molten metal is 1
The method for producing an oil-free composite alloy according to any one of claims 1 to 4, wherein crystals are crystallized in a size of 15 µ to 150 µ per millimeter square field and 5 to 10 are scattered.