JP2005126782A - Wear resistant component, and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact and inexpensive wear resistant component by increasing its hardness and imparting sufficient wear resistance thereto, and to provide its production method. <P>SOLUTION: In the production method, alloy powder with a grain size of <30 micrometer is subjected to metal injection molding to produce a stock, or alloy powder with a grain size of ≥40 micrometer is subjected to compact sintering to produce a stock, and nitriding treatment is performed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

    The present invention relates to a wear-resistant component that is used with increased hardness by heat treatment and a method for manufacturing the same.

  Wear resistant parts used with increased hardness in electric compressors of air conditioners, etc., after roughing nitrided steel such as SACM645, nitriding treatment is performed and finishing is performed to harden the surface to about Hv900 And use it.

  In this case, the material forming of the nitrided steel is performed by cutting out from the steel material of the molten material, or forming the molten material by hot forging with an accuracy of about 1 millimeter on one side of the rough machining, and then cutting out the material. However, it is difficult to manufacture parts. However, in such a process, there is a problem that it is not easy to manufacture parts and manufacturing costs are high.

  Further, as shown in FIG. 4, the finishing region 14 is removed by the finishing process after the nitriding treatment, and the exposed surface 15 becomes the use surface, but the hardness of the use surface 15 is only about Hv950.

  Therefore, after grinding to remove the surface of the wear-resistant parts for compressors, nitriding to harden the surface is performed, and further grinding to remove the surface within a range of 0.25 mm or less in diameter is performed. Some have been proposed in which the hardness of the moving surface is Hv1000 or more (see, for example, Patent Document 1).

JP 2002-98052 A

  Recently, since the size of parts is required to be reduced, the force applied to wear-resistant parts tends to increase. Even if the method described in Patent Document 1 is used, the wear-resistant parts having sufficient wear resistance can be reduced in size. There is a problem that it is difficult.

  The present invention has been made in view of the above-described problems of the prior art, and provides a small and inexpensive wear-resistant component by increasing hardness and imparting sufficient wear resistance, and a method for manufacturing the wear-resistant component. The purpose is to do.

  In order to achieve the above object, the invention according to claim 1 of the present invention is to manufacture a material by metal injection molding using an alloy powder having a particle size of less than 30 micrometers and perform nitriding treatment. This is a method for manufacturing a wear-resistant part characterized by the following.

  According to a second aspect of the present invention, there is provided a wear-resistant part characterized in that a material is produced by compacting and sintering using an alloy powder having a particle size of 40 micrometers or more and subjected to nitriding treatment. It is a manufacturing method.

  Furthermore, the invention described in claim 3 is a wear-resistant part manufactured by the manufacturing method described in claim 1 or 2.

  According to the present invention, a raw material is manufactured by metal injection molding using an alloy powder having a particle size of less than 30 micrometers, or a green compact is sintered using an alloy powder having a particle diameter of 40 micrometers or more. Since the material is manufactured by sinter molding and nitriding is performed, the surface hardness can be improved and sufficient wear resistance can be imparted compared to the melted material, and a small wear-resistant part can be provided. Can do. In addition, as compared with the production from the melted material, the machining allowance for the rough machining can be reduced, so that the production cost is reduced and an inexpensive wear-resistant part can be provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 shows a part used for a scroll compressor called a compla bush, and is an example of a wear-resistant part according to the first embodiment of the present invention.

  This wear-resistant part 1 is manufactured by metal injection molding of stainless steel powder particles equivalent to SUS420J2, and after the inner and outer parts are roughly processed to a thickness of about 0.05 to 0.2 millimeters, the temperature is about 590 ° C. The nitriding treatment is performed for about 9 hours, and then the inner and outer sides are subjected to a finishing process of 20 to 100 micrometers. Note that the dense and adhesive strong oxide film on the surface of chromium-containing stainless steel or heat-resistant steel is removed using, for example, organic chloride, hydrogen fluoride, hydrogen sulfide, or the like.

  FIG. 2 is a hardness distribution curve of the wear-resistant component shown in FIG. 1 and a component obtained by nitriding a molten material of the same material under the same conditions. The vertical axis represents the micro Vickers hardness, and the horizontal axis represents the distance from the surface.

  As can be seen from FIG. 2, the hardness 2 after nitriding of the part manufactured by metal injection molding is increased by nearly 150 points compared to the hardness 3 of the part manufactured from the molten material of the same component. It can be seen that the depth of is shallower. This is because so-called decarburization in which carbon escapes from the chromium carbide occurs because the metal injection-molded product is fired under conditions where air of about 2 bar is present. This decarburization occurs while the metal injection molded product is dewaxed and sintered to a density of 98% or more from a state where the density is about 50%, and thus decarburization has occurred to the inside. After firing, when roughing is performed and further nitriding is performed, chromium effective for hardening by nitriding remains more than the smelted material due to decarburization, so there is more chromium nitride than the nitriding product of the smelted material. It is thought that the hardness becomes stiff.

  In addition, the metal injection molded product has a lower hardness than the melted material. If the nitriding treatment is the same, the metal injection molded product has a large amount of chromium, so that nitrogen forming chromium nitride is formed on the surface side. It is thought that it is consumed. In addition, it is easy to obtain the same depth of hardness as that of the molten metal by extending the time, adjusting the ammonia gas concentration, etc., so it is easier to achieve a hard surface. can do.

  Furthermore, if the main purpose is to obtain a hard surface, it is sufficient to perform the treatment under the same nitriding conditions as the melted material, which is economical, and higher hardness can be obtained by nitriding than the melted material. Miniaturization of wear parts can be achieved. Further, since the dimensional accuracy of the material is high and the machining allowance by rough machining can be reduced, the machining cost can be suppressed, and an inexpensive wear-resistant part can be provided.

なお、表１における記号の意味は以下のとおりである。
〇：良好な耐摩耗部品の製作が可能
△：使用可能な耐摩耗部品の製作が可能
×：耐摩耗部品の製作が不可能 When wear-resistant parts were manufactured using alloy powders of various particle sizes as metal injection molding, the results shown in Table 1 were obtained.

The meanings of symbols in Table 1 are as follows.
○: Good wear-resistant parts can be manufactured △: Usable wear-resistant parts can be manufactured ×: Wear-resistant parts cannot be manufactured

  Although the present embodiment has been described by taking metal injection molding of stainless steel as an example, the same effect can be obtained even if die steel is used. Further, although this embodiment has been described by taking nitriding as an example, the same effect can be obtained by soft nitriding or ion nitriding.

Embodiment 2. FIG.
In the present embodiment, the wear-resistant component 1 shown in FIG. 1 is manufactured by powder compaction molding using stainless steel powder particles equivalent to SUS440C, and the inner side and the outer side are 0.1-0. After rough processing of about 3 millimeters, nitriding treatment is performed at a temperature of about 500 ° C. for about 6 hours, and then the inner and outer sides are finished by 20 to 100 micrometers. Note that the dense and adhesive strong oxide film on the surface of chromium-containing stainless steel or heat-resistant steel is removed using, for example, organic chloride, hydrogen fluoride, hydrogen sulfide, or the like.

  FIG. 3 is a hardness distribution curve of a wear-resistant component according to the present embodiment and a component obtained by performing nitriding treatment on a molten material of the same material under the same conditions. The vertical axis represents the micro Vickers hardness, and the horizontal axis represents the distance from the surface.

  As can be seen from FIG. 3, the hardness 5 after nitriding of a part manufactured by green compact molding is increased by nearly 50 points compared to the hardness 6 of a part manufactured from the molten material of the same component. It can be seen that the depth of the hard part is shallow. This is because an alloy powder having a large particle size of 40 micrometers or more is used, so that the density increases only to about 85%, and the nitriding gas enters from the gap between the alloy powders, so that nitrogen is introduced from the outer periphery of the alloy powder. Since it penetrates and the whole powder becomes hard, it is considered that it becomes harder than a melted material having a density of 100%.

  In addition, the compacted sintered product has a lower hardness than the melted material because the surface area to be nitrided is large because nitrogen penetrates from the outer periphery of the alloy powder under the same nitriding conditions as the melted material. Therefore, it is considered that a large amount of nitrogen is consumed. In addition, it is easy to obtain a depth of hardness equivalent to that of the smelted material even if the green compact is formed by extending the time or adjusting the ammonia gas concentration. Can be easily realized.

  Furthermore, if the main purpose is to obtain a hard surface, the treatment may be performed under the same nitriding conditions as the melted material, which is economical. In addition, since it is possible to obtain higher hardness by nitriding than melted material, it is possible to reduce the size of wear-resistant parts by producing materials using sintered compacts and performing nitriding. it can. Furthermore, since the dimensional accuracy of the material is high and the machining allowance by rough machining can be reduced, machining costs can be suppressed, and inexpensive wear-resistant parts can be provided.

なお、表２における記号の意味は以下のとおりである。
〇：良好な耐摩耗部品の製作が可能
△：使用可能な耐摩耗部品の製作が可能
×：耐摩耗部品の製作が不可能 When wear-resistant parts were produced using alloy powders of various particle sizes as the powder compact for green compact sintering, the results shown in Table 2 were obtained.

The meanings of symbols in Table 2 are as follows.
○: Good wear-resistant parts can be manufactured △: Usable wear-resistant parts can be manufactured ×: Wear-resistant parts cannot be manufactured

  Although the present embodiment has been described by taking the green compact sintering of stainless steel as an example, the same effect can be obtained even if die steel is used. Further, although this embodiment has been described by taking nitriding as an example, the same effect can be obtained by soft nitriding or ion nitriding.

  According to the present invention, the surface hardness can be improved and sufficient wear resistance can be imparted, and the machining allowance for the rough machining can be reduced and the production cost can be reduced. It can be used effectively for sliding parts such as engines or compressors.

It is a perspective view of the wear-resistant component concerning Embodiment 1 or 2 of this invention. It is a hardness distribution curve of the wear-resistant component concerning Embodiment 1 of this invention, and the component which performed the nitriding process on the molten metal of the equivalent material on the same conditions. It is a hardness distribution curve of the wear-resistant component concerning Embodiment 2 of this invention, and the component which performed the nitriding process on the same conditions to the molten material of the equivalent material. It is a hardness curve after the nitriding process of the conventional wear-resistant component.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wear-resistant part 2 Hardness curve after baking and nitriding SUS420J2 3 Hardness curve of nitriding treatment of SUS410S melted material 5 Hardness curve of nitriding treatment of SUS440C green compact 6 SUS440C melted material Nitriding hardness curve

Claims (3)

A method for producing a wear-resistant component, comprising producing a material by metal injection molding using an alloy powder having a particle size of less than 30 micrometers and performing nitriding treatment. A method for producing a wear-resistant part, characterized in that an alloy powder having a particle size of 40 micrometers or more is used to produce a raw material by green compact sintering and nitriding. A wear-resistant part manufactured by the manufacturing method according to claim 1 or 2.

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