JP2002263853A - Method for assembling and welding high-temperature mechanical component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a metal precision mechanical component by liquid phase diffusion welding in assembling the mechanical component internally having complicated and precise pipe lines for carrying liquid and lightning weight. SOLUTION: In the precision mechanical component in which the component to be welded, which has internal pipe lines when finishing assembly and is divided into at least two or more at a cross section passing through the internal pipe lines, is assembled by the liquid phase diffusion welding after the liquid phase diffusion welding, a difference in level caused by defective butting produced in the inner surface of the pipe line or excess metal produced when stress is loaded during the welding of metal to be welded are internally ground while being enlarged by a drilling machine having a diameter larger than that of the pipe line, or further finishing is carried out in order to remove the difference in level of the outer surface of a product and oxide scales or projecting and recessing pars produced in welding.

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 an internal pipe at the end of assembly and a cross section passing through the internal pipe. When assembling the parts to be joined divided into at least two or more parts by liquid phase diffusion bonding, after the diffusion parts are subjected to the diffusion bonding process, a step caused by a poor butting generated on the inner surface of the pipeline, or a stress load during the joining of the joining metal. This is a method of grinding the inner surface while enlarging the extra pile generated by the drilling machine having a diameter larger than the pipe diameter.The present invention further removes a step on the outer surface of the product, an oxide scale generated at the time of joining, and unevenness. A method for assembling and joining high-temperature machine parts, which is characterized by performing a finishing process to perform the finishing. Further, the liquid phase diffusion bonding in the present invention is a method for assembling and bonding high temperature mechanical parts, which 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. There is no particular limitation on the composition of the amorphous alloy for realizing the liquid phase diffusion bonding, including the alloy described in U.S. Pat. No. 4,144,058 and the P alloy described in JP-A-49-91014. , B, C
And the like as a diffusion atom.

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.

According to the present invention, the above-mentioned divided material to be joined has an internal conduit at the end of assembly as a product, and a part to be joined which is divided into at least two parts in a cross section passing through the internal conduit is subjected to liquid phase diffusion. After joining by liquid phase diffusion bonding, a step caused by poor butting generated on the inner surface of the pipe, or the extra height generated when stress is applied during the bonding of the metal to be bonded, is used as a pipe. The inner surface is ground while being enlarged by a punch having a diameter larger than the path diameter, or a finishing process is performed to remove a step on the outer surface of the product, an oxide scale and irregularities generated at the time of joining.

In the present invention, precision machine parts divided into a plurality of parts having a pipe inside as described above, for example,
Manufacturing of a fuel injection valve made of high carbon steel containing 1.0% of Cr and 0.5% of Mo as shown in FIG. 1 will be described. That is, in the case where the above-mentioned divided parts are manufactured and then the divided parts are abutted and diffusion-bonded, first, one of the divided parts is an amorphous base containing a 30 μm-thick Ni base and a small amount of P, B, C, etc. in an Fe base. A liquid-phase diffusion bonding alloy foil of a high-quality alloy is placed, and the other divided parts are butt-butted on top of each other, and diffusion bonding is performed at a high temperature in a state where the required stress is applied by a holding jig and completely fixed. Among the precision machine parts integrated in this way, there are frequent steps such as a step formed on the inner surface of the pipe line due to a poor butting between the divided parts, or a surplus generated when a stress is applied during the joining of the joining metal. there is a possibility. Therefore, it is necessary to remove these steps or extra piles. In the present invention, these have a diameter slightly larger than the pipe of the component, for example, the pipe diameter is increased by a drilling machine having a drill at the tip. The inner surface of the pipeline is finished by grinding the inner surface while expanding.

On the other hand, the outer surface of the above-mentioned part after the liquid phase diffusion bonding treatment is formed in the same manner as described above, due to a step formed on the inner surface of the pipe due to a poor butting between the divided parts, or when a stress is applied during the joining of the joining metal. In addition to the excess, the oxide scale generated during bonding appears as burrs. In addition, surface irregularities and the like during the production of the divided parts may remain. In this case, the present invention includes a step of finishing the final product by means such as outer surface, grinding, or outer surface polishing.

The conditions of the liquid phase diffusion bonding are as follows.
A method of heating to a temperature equal to or higher than the solidus line and performing liquid phase diffusion bonding at a temperature of 1000 to 1300 ° C. for 60 to 120 seconds while applying stress to the bonding surface is adopted. By this liquid phase diffusion bonding, a strong bonding surface can be obtained if it can be diffused from the alloy for diffusion bonding to a required amount and diffused to the bonding portion. When performing the liquid phase diffusion bonding, N ₂ or Ar is blown onto the inner and outer surfaces of the material to be bonded in an oxidizing atmosphere containing 0.01% by mass or more of oxygen, preferably in the air. Is preferably performed.

[0015] The structure of the material to be joined obtained by the liquid phase diffusion bonding treatment described above 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.

Further, in the present invention, the characteristics of the joint surface can be freely changed depending on the specifications of the machine 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.

[0017]

<Embodiment 1> In the present invention, the manufacture of an automobile fuel injection valve having a fuel supply pipe therein will be described. As shown in FIG. 1, this automobile fuel injection valve 1 has C
B: a 30 μm thick B is formed between the half-divided surfaces 1 and 2 obtained by forging a high-carbon steel containing r: 1.0% and Mo: 0.5% by dividing the pipeline into two parallel surfaces. A liquid-phase diffusion bonding alloy foil made of a Ni-based amorphous alloy containing a small amount of P and P is sandwiched, and the component is pressed from above and below the external upper and lower surfaces by a holding jig, and the entire component can be atmosphere controlled with a high-frequency induction heating coil. Liquid phase diffusion bonding temperature in high frequency induction heating furnace (not shown): 11
Liquid phase diffusion treatment was performed at 50 ° C. to produce integrated precision mechanical parts.

[0018] Among the precision machine parts manufactured in this manner, there are steps due to a positional deviation of the pipe line due to a poor butting between the divided parts, burrs of a joining metal, and the like, and liquid phase diffusion bonding on the outer surface of the parts. Occasionally generated parts, such as oxide scale, were also observed. For such a part, the inner surface was pierced with a drill having a diameter slightly larger than the part conduit to finish the inner surface, and the outer surface was poorly polished and buffed to obtain a product.

[0019]

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) 3C043 AC11 CC01 3G066 BA54 BA61 CC01 CC66 CD14 CD15 CD21 CD28 CD30 4E067 AA02 AB02 AB05 AD03 BA05 DA17 DB05 DC06 EA07 EB00

Claims (3)

[Claims] At the end of assembling, a part to be joined having an internal pipe at the cross section passing through the internal pipe and divided into at least two parts by liquid phase diffusion bonding is assembled by diffusion bonding. After the treatment, it is necessary to increase the level difference caused by the poor abutment generated on the inner surface of the pipeline, or the extra height generated at the time of stress loading during joining of the joining metal, while expanding the inner surface with a drilling machine having a diameter larger than the pipeline diameter. Characteristic method of assembling and joining high temperature mechanical parts. 2. The method for assembling and joining high-temperature mechanical parts according to claim 1, further comprising the step of removing a step on the outer surface of the product, an oxide scale and irregularities generated at the time of joining. 3. The method as claimed in claim 1, wherein the liquid phase diffusion bonding is performed in an oxidizing atmosphere.