JP2002263859A - Pressing tool for manufacturing mechanical component by diffusion welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a metal precision mechanical component by liquid phase diffusion welding when assembling the mechanical component which internally has complicated and precise pipe lines for carrying liquid and lightening weight. SOLUTION: In a pressing tool for manufacturing the mechanical component by the diffusion welding, when the mechanical component which has surfaces divided into at least two or more is welded by the liquid phase diffusion welding and is assembled, the component is pressed by the tool composed of an oxide, nitride or composite material and non-metallic material pressing at least one side of an outer surface and having compressing yield strength not lower than 10 MPa at 1,000-1,300 deg.C over an area equivalent to 30% or more of the whole welding surface of a material to be welded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to various types of mechanical parts manufactured by using a diffusion bonding technique, and more particularly, to machining such as cutting, shaving, punching, and die cutting from a material, or casting directly from a molten metal. The present invention relates to a machine component manufactured by liquid phase diffusion bonding instead of machining of a machine component having an annular or hollow shape by forging or the like.

[0002]

2. Description of the Related Art Conventionally, it has an annular or hollow shape,
In particular, mechanical parts, such as bearings of rotating parts, bearings, and sliding pipes of cylinders, for which various properties such as wear resistance, corrosion resistance and fatigue resistance are individually or simultaneously required for a long time, are required quality. In order to satisfy the following requirements, for example, in a bearing steel represented by JIS-SUJ, which has a relatively high alloy ratio, in addition to C: 1% and Cr: 1%, Mn,
Although a steel material containing Mo is used, it is often difficult to assemble parts by welding or the like. For this purpose, machine parts with complex shapes are cut out of massive steel ingots or roughly formed by hot forging or drilling, and after finishing, spheroidizing and carburizing according to required specifications. And manufacturing. Therefore, the cost of various processing steps in the manufacturing process accounts for the majority of the product price, rather than the price of the raw material ingot. On the other hand, precision mechanical parts, such as automobiles, which require high reliability are also required to have long-term durability, and are aimed at reducing specification costs over a long period of time. Therefore, even if expensive, these precision machine parts manufactured from the bulk metal by the conventional manufacturing method are frequently used, and this causes an increase in the price of many parts and eventually the price of the final product.

[0003] Of the methods of processing a metal material into an arbitrary shape, hot rolling and press molding are generally employed as methods with the highest mass productivity and low cost. It has a simple shape, often a simple shape such as a plate, and is suitable for mass production.However, it is not possible to directly manufacture hollow machine parts and annular parts with high yield by the above-mentioned rolling and press molding. It is difficult due to the shape restrictions, and it is currently not industrialized at all. Therefore, there is no industrially established technology for efficiently mass-producing complicated precision machine parts having an annular or hollow shape. On the other hand, from the viewpoint of cost reduction, there is a long-awaited need to develop a completely different manufacturing process. Have been.

On the other hand, recently, the technique of liquid phase diffusion bonding has been spotlighted. This liquid-phase diffusion bonding technique uses an alloy having a lower melting point compared to the material to be bonded, for example, 50% or more of the crystal structure is substantially amorphous in the bonding surface of the material to be bonded, that is, between the grooves. A multi-element alloy, such as B, P, Ni, Fe, etc., which is a material and has the ability to form a joint through a diffusion-controlled isothermal solidification process, is brought to a temperature equal to or higher than the melting point of the low melting point alloy into which the joint is inserted. This is a technique for forming a joint in the isothermal solidification process by heating and holding.

The liquid-phase diffusion bonding technique has a feature that, unlike ordinary welding techniques, there is almost no welding residual stress, or a smooth and precise joint can be formed without generation of excess as in welding. ing. Moreover, since this technology is surface bonding, the bonding time is constant regardless of the area of the bonding surface,
It has the advantage that the joining is completed in a relatively short time, and is a joining technique completely different from conventional welding. Therefore, if even a groove can be inserted and maintained at a temperature equal to or higher than the low melting point metal for a predetermined time, bonding between surfaces can be realized regardless of the shape of the groove. On the other hand, with respect to conventional liquid phase diffusion bonding that can be realized only in a non-oxidizing atmosphere, an alloy foil for liquid phase diffusion bonding that can be applied even in an oxidizing atmosphere is known. (Patent No. 189
No. 1618, No. 1891619, No. 183775
No. 2). However, at present, this liquid phase diffusion bonding technique is applied only to the bonding of members having a relatively large bonding surface area, and is not used for bonding precision mechanical parts and the like.

[0006]

SUMMARY OF THE INVENTION The present invention provides a complex precision machine part having an annular or hollow shape, which simultaneously satisfies various characteristics of wear resistance, corrosion resistance and fatigue resistance, with high efficiency and low cost. It is an object of the present invention to provide a mass-produced diffusion bonding machine part.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the gist of the present invention is to provide a liquid-phase diffusion bonding of a mechanical part having at least two or more divided surfaces. Upon joining and assembling, the part is made of oxide, nitride or a composite material of
A holding jig for manufacturing a diffusion bonding machine part, wherein the holding jig is held by a jig made of a nonmetal material having a compression strength of 10 MPa or more at 0 to 1300 ° C.
In the above-mentioned joining, 1000 to 1000% or more of the entire area of the joining surface of the materials to be joined from at least one outer surface.
A holding jig for manufacturing a diffusion bonding machine part, wherein the holding jig is held by a jig made of a nonmetallic material having a compressive strength of 10 MPa or more at 1300 ° C. Further, the liquid phase diffusion bonding in the present invention is performed in an oxidizing atmosphere.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In practicing the present invention, the material of a target mechanical part is not particularly limited. The technology of the present invention can be applied to all metal materials that can be liquid-phase diffusion bonded. For example, liquid phase diffusion bonding can realize a joining joint even with a material to which normal welding is difficult to apply, such as normal carbon steel, high carbon steel, and low carbon steel. Also,
Stainless steel containing various ratios of Cr or Ni,
Liquid phase diffusion bonding of highly corrosion-resistant alloy steel, Ni-based alloys and other alloys based on Ni, and non-ferrous materials such as Al, Ti, Zn and other practical metals, all using the appropriate joining alloy Becomes possible. Further, there is no limitation on the composition of the amorphous alloy for realizing the liquid phase diffusion bonding, and the alloys described in U.S. Pat. No. 4,144,058 and the alloys described in JP-A-49-91014 are disclosed. Of P,
Liquid phase diffusion bonding alloys containing B, C, etc. as diffusion atoms can be used.

In the present invention, using the above-mentioned material to be bonded and the alloy for liquid phase diffusion bonding, a pipe having a purpose for carrying a fluid, reducing a weight, or passing through a sliding part is provided. Equipped with precision machine parts originally manufactured by integral molding, first divided into a plurality of parts on the plane including the pipeline, for example, press molding or rolling, grinding, polishing, etc. It is necessary to carry out a manufacturing process through an inexpensive manufacturing process for a combination of processing, assemble them via a liquid phase diffusion bonding alloy, and integrate them by liquid phase diffusion bonding.

At this time, it is necessary that the parts to be divided be divided by a surface passing through a pipe existing inside, in comparison with the final shape. And it can be manufactured by a simple method. Also, this division can be made as many as two or more,
As a result of simplification of the production and complicated or large number of the production steps, it may be appropriately selected within a range that does not become expensive compared to the conventional production steps. Further, the division surface may be a flat surface, a curved surface, a continuous or discontinuous multi-surface or a curved surface, and the shape may be appropriately selected so that the division facilitates production of each part. In addition, the conduit inside the component of the final shape may be a single continuous path or a plurality of independent paths, the shape of the conduit itself is free, and the surfaces to be joined at the time of assembly only need to correspond, particularly No restrictions. The conduit can be assembled with or without an opening to the outer surface. In addition, the characteristics of the joint vary variously depending on the combination of the material to be joined and the alloy for liquid phase diffusion joining.

In the present invention, precision machine parts divided into a plurality of parts having a pipe inside as described above, for example,
As shown in FIG. 1, a Ni-based liquid phase is formed on a split surface divided into two by a surface parallel to a pipe of an automobile fuel injection valve made of high carbon steel containing Cr: 1.0% and Mo: 0.5%. At the time of assembling via a diffusion bonding alloy and performing liquid phase diffusion bonding, in order to obtain the diffusion bonding efficiency and the required bonding strength of the divided materials to be bonded (members to be bonded), the materials to be bonded are pressed from the outer surface with a jig. It is necessary to apply a desired stress and hold it down. The holding jig must be made of a material that can sufficiently withstand the liquid phase diffusion processing temperature. That is, the liquid phase diffusion treatment temperature is 1000 to 1
In order to reach a high temperature of 300 ° C and to process while applying a large stress load of 10 MPa or more to the material to be joined,
The material must be excellent in heat resistance and high-temperature strength.
The present inventors have searched for a material that can meet this demand, and have tried using a normal Cr-Mo heat-resistant alloy steel on a trial basis, but with a stress load of 10 MPa at the above liquid phase diffusion treatment temperature. Since a buckling phenomenon was observed, no buckling phenomenon was observed when silicon nitride, which is a ceramic made of an oxide, a nitride, or a composite material thereof, was used, and it was found that this ceramic material was optimal.

Further, when the present inventors hold down with a jig made of the non-metallic material, at least one outer surface of the non-metallic material is cured to a substantial area of 30% or more of the entire joining surface of the material to be joined. It has been found that a diffusion bonding machine part having a strong bonding strength can be manufactured by holding with a tool. The holding area of this holding jig is 10
Ideally, it is 0%, but the outer surface of the non-metallic material often has a complicated shape, and therefore, the holding area of the non-metallic material causes an excessively small bonding area between the bonding surfaces of the non-metallic material. Therefore, it is necessary to increase the bonding area as much as possible because diffusion bonding becomes non-uniform, and it depends on the external shape of the nonmetallic material.

The structure of the material to be joined obtained by the above-mentioned liquid phase diffusion bonding treatment is martensite or bainite classified as a low-temperature transformation formation structure, and the joining metal and the joining material metal are contained in the joining metal. If a structure having the same low-temperature transformation generation structure as that of the material to be joined in part or all is obtained by the alloying generated by the fusion of the materials, a similarly strong joint surface can be obtained. In the present invention, the liquid-phase diffusion bonding is performed in an oxidizing atmosphere containing 0.01% by mass or more of oxygen, preferably in the atmosphere, by N ₂ or Ar.
Is preferably sprayed onto the inner and outer surfaces of the material to be joined to perform the joining operation.

Further, in the present invention, the characteristics of the joint surface can be freely changed depending on the specifications of the mechanical parts to be applied, and the characteristics as the joint are not particularly limited. The joint efficiency does not need to be 1, nor does it need to be completely homogenized organizationally. Of course, it is preferable that the joint efficiency is 1 and the body is completely homogenous in terms of the characteristics of the mechanical part, but it can be determined according to the manufacturing cost of the part. In addition, after the assembly is completed, it is possible to perform various heat treatments, chemical conversion treatments, and processes on the mechanical components.For example, in the case of steel materials, quenching, tempering, normalizing, annealing, and the like are performed alone. Alternatively, a composite and repeated application in some cases is effective for improving the characteristics as a component, and does not hinder the effects of the present invention at all. Further, carburizing treatment, nitriding treatment, plating, or spraying treatment such as painting or powdering, and surface processing such as shot blasting are also effective.

[0015]

<Embodiment 1> In the present invention, the manufacture of an automobile fuel injection valve having a fuel supply pipe therein will be described. This automobile fuel injection valve has a Cr:
B, having a thickness of 30 μm, is formed between the divided surfaces 1 and 2 of a half part, which is divided into two parts by a forging made of high carbon steel containing 1.0% and Mo: 0.5%. A liquid-phase diffusion bonding alloy made of a Ni-based amorphous alloy containing a small amount of P is sandwiched, the parts are butted, and the parts are pressed from above and below the outer surfaces with a holding jig made of silicon nitride. Liquid phase diffusion bonding temperature in an atmosphere controllable high-frequency induction heating furnace having an induction heating coil: starting heating from 1100 ° C., and when reaching 1150 ° C., for 90 to 120 seconds,
Continue to apply the applied stress of 2MPa or more to the joint surface with the holding jig, then reduce the applied stress and keep it as low stress or no load for 5 minutes. In order to prevent quench cracking to a temperature higher than the non-diffusion transformation temperature, it is quenched at a cooling rate of 5 ° C./sec or more, then left to cool and maintain this cooling until the transformation is completed, and then 1 ° C. to room temperature Rapid cooling was performed at a cooling rate of / sec or more. By performing such processing,
The structure of the material to be joined is classified as a low-temperature transformation generation structure, and is a bainite, and in a portion of the joining metal diffusion bonded by fusion of the joining metal and the joining material metal, the same as the joining material. Some or all of them had a low-temperature transformation formation structure. After that, it was finished to the final outer shape to obtain a product of an automotive fuel injection valve. When this was incorporated and used as an actual automobile part, the same performance as that of a conventional machined automobile fuel injection valve was obtained, and the high-temperature oxidation resistance, abrasion resistance, and the joint surface strength against fluid pressure were not improved. A comparable value was obtained.

[0016]

As described above, the present invention makes it easy to manufacture precision machine parts such as fuel injection valves for automobiles having a complicated and precise pipe inside, which are originally manufactured by integral molding. By adopting the process of bonding them from the manufacturable divided parts by liquid phase diffusion bonding technology,
The present invention makes it possible to manufacture metal precision machine parts at low cost and efficiently.

[Brief description of the drawings]

FIG. 1 is a view showing a divided part shape in a case where a mechanical part manufactured by integral molding is divided by a surface passing through a pipe provided therein, particularly showing an example of a fluid injection valve.

Continued on the front page (72) Inventor Yasushi Hasegawa 5-3 Tokai-cho, Tokai City, Aichi Prefecture Inside Nagoya Works, Nippon Steel Corporation (72) Inventor Yutaka Takagi 4005 Nishi-Oguma, Oguma-cho, Hashima City, Gifu Prefecture Fukushou Kogyo F term in reference (reference) 4E067 BA05 DA13 DA17 DB05 DC03 DC06 EB00

Claims (3)

[Claims] At the time of assembling a mechanical part having at least two or more divided surfaces by liquid phase diffusion bonding, the part is made of an oxide, a nitride or a composite material thereof, and has a temperature of 1000 to 1300 ° C. A jig made of a nonmetallic material having a compressive strength of 10 MPa or more. 2. A jig made of a non-metallic material having a compressive strength of 10 MPa or more at 1000 to 1300 ° C. from at least one outer surface in an equivalent area of 30% or more of the entire joining surface of the material to be joined in said joining. The holding jig for manufacturing a diffusion bonding machine part according to claim 1, wherein the holding jig is held down. 3. The holding jig for manufacturing a diffusion-bonded machine part according to claim 1, wherein the liquid-phase diffusion bonding is performed in an oxidizing atmosphere.