JPH03188205A - Wear resistant machine parts and manufacture thereof - Google Patents

Abstract

PURPOSE:To manufacture machine parts constituted of metal body composed of complex structure and improved in wear resistance by pressurized-sintering a metal basis having deep hardening metal powder surface and shallow hardening metal powder surface on the front and back surfaces respectively. CONSTITUTION:For example, in the case of manufacturing a cylindrical track bush, a first metal powder material 2 and a second metal powder material 3 are packed so that the first metal powder material 2, where a hardening layer having high hardness and deep quenched thickness is obtd., exists on outer diameter face side in a capsule 1, which is burnt out with heat similar heating of the tack bush and the second metal powder material 3, where the shallow hardness layer is obtd., exists on inner diameter face side. Successively, the air in the capsule 1 is sufficiently removed through air exhaust hole 4 and this hole 4 is sealed and the capsule is charged into an HIP apparatus 5 and heated at about 1,000-1,200 deg.C with a heater 6 and also 200-1,000 kg/cm<2> of pressure is applied with compressed gas 7 to obtain the sintered body 8 integrating the deep and shallow hardening metal powders 2, 3. After machining this sintered body 8 having complex layer to the prescribed dimension, by executing the quenching to the inner and outer diameter surfaces at the same time, the track bush having high accuracy is obtd.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a wear-resistant mechanical component, and more particularly to a wear-resistant mechanical component having first and second wear-resistant surfaces facing each other. It is.

[Prior Art] This type of wear-resistant mechanical component has conventionally been used, for example, a cylindrical track used in the track of a tracked vehicle in which the outer diameter surface and the inner diameter surface are the first and second wear-resistant surfaces that are front and back. Bush is made of low alloy steel (SCM 415) 1,420)
1 etc.), and a hardened layer is formed on the outer diameter side and the inner diameter side by carburizing and quenching.

Note that the depth and hardness of this hardened layer are proportional to the wear resistance, and by carburizing and quenching, carbon is diffused into the treated surface and then quenched to achieve a Rockwell hardness of 60~60. About 62 cured layers are obtained.

[Problems to be Solved by the Invention] However, the above-mentioned thing requires high wear resistance on the outer diameter side like a track bushing, and the inner diameter side requires high wear resistance on the outer diameter side. Even in cases where hardness is not required, hardened layers with the same abrasiveness and the same depth are formed on the outer diameter side and the inner diameter side.

Therefore, if a metal substrate with low hardness and high toughness is secured between the hardened layer on the outer diameter side and the hardened layer on the inner diameter side, it will function as a wear-resistant mechanical part and limit the thickness between the two surfaces. In this case, a hardened layer of the same depth is formed on the inner diameter side, so the hardened layer on the outer diameter side, which requires high wear resistance, cannot be sufficiently deep, resulting in a lack of wear resistance. Therefore, there is a problem that the wear resistance life as a mechanical part is shortened.

In addition, if an attempt is made to prevent the depth of carburization by performing carburization treatment on a surface that may have low wear resistance, there is a problem in that an additional process is required and productivity is poor.

Furthermore, Japanese Patent Application Laid-open No. 59-77979 discloses a means for imparting the required hardness to the inner circumferential surface by induction hardening the track bushing from the outer circumferential surface and the inner circumferential surface toward the center of the wall thickness. However, even when using this method, multiple quenching steps are required, first hardening the outer peripheral surface and then hardening the inner peripheral surface, and low-temperature tempering is performed after both of these steps are completed. However, it is difficult to expect productivity to improve.

The purpose of the present invention is to solve the above-mentioned problems, and while it is highly productive, it is possible to obtain a deep hardened layer on the required wear-resistant side to obtain sufficiently high wear resistance. Furthermore, it is an object of the present invention to provide a wear-resistant mechanical component that can sufficiently secure a metal base portion with high toughness and improve the wear-resistant life of the mechanical component.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the mechanical component of the present invention is a wear-resistant mechanical component that has first and second wear-resistant surfaces facing each other, and has a high quenching hardness; The metal part forming the first wear-resistant surface side is produced from a first metal powder material that provides a deep hardened layer, and the second wear-resistant surface is produced from a second metal powder material that provides a shallow hardened layer. Consisting of a metal body with a multi-layer structure having a metal part forming an abrasion-resistant side, and a metal base part existing between the metal part on the first wear-resistant side and the metal part on the second wear-resistant side. be done.

Further, the method for manufacturing a wear-resistant mechanical component according to the present invention includes: a method for manufacturing a wear-resistant mechanical component having first and second wear-resistant surfaces on the front and back sides, wherein the first wear-resistant surface side has: The first and second metal powder materials are arranged so that the first metal powder material with high quench hardness and a deep hardened layer is located on the second wear-resistant side, and the second metal powder material with a shallow hardened layer is located on the second wear-resistant side. a step of forming a multilayer structure of a second metal powder material; a step of sintering the formed multilayer structure of the first and second metal powder materials by hot isostatic pressing; It consists of a step of hardening the multilayer structure of first and second metal powder materials.

[Function] By quenching the multilayer structure of the first metal powder material that has a high hardness and a deep hardened layer, and the second metal powder material that provides a shallow hardened layer, it is possible to achieve both convenience. This makes it possible to leave a metal base part between the layers that has high toughness and improves fatigue strength. A deep hardened layer can be obtained on the abrasion resistant side that requires high abrasion resistance, and a shallow hardened layer can be obtained on the abrasion resistant side that requires relatively low abrasion resistance.

[Effects of the invention] Therefore, although it is highly productive with only quenching, it is possible to obtain a deep hardened layer on the required wear-resistant side to obtain sufficiently high wear resistance, and to achieve relatively low wear resistance. The shallow hardened layer on the side with good wear resistance provides a metal substrate with sufficient toughness, ensuring fatigue strength and improving the wear resistance life of mechanical parts.

[Example] Next, a specific example of the present invention will be described in detail with reference to the drawings.

To explain a cylindrical track bushing whose first surface is the outer diameter side and whose second surface is the inner diameter side, this mechanical part is obtained by the process shown in Figures 1 to 4. It will be done. First, as shown in Fig. 1, a capsule 1 made of, for example, synthetic resin and similar to the target mechanical part is burnt out by heating.
(In this example, it is similar to a cylindrical track bushing and has a slightly smaller inner diameter and a slightly larger outer diameter and length than the target product.) Deep hardening metal powder 2 with high hardenability is present as a metal powder material, and shallow hardening metal powder 3 with hardenability lower than the first metal powder material is present on the inner diameter side as a second metal powder material. The deep hardening metal powder 2 and the shallow hardening metal powder 3 are respectively filled in such a manner. Next, as shown in FIG. 2, close the upper opening of the capsule I, and
The air inside the capsule 1 is sufficiently degassed, and the degassing port 4 is immediately sealed after degassing. The sealed capsule 1 is placed in a HIP device 5 where hot isostatic pressing is performed, as shown in FIG. In this HIP device 5, the heating temperature is 1000℃~1200t by the heater 6 provided inside.
20 by the compressed gas 7 introduced while being heated to 20
The deep and shallow hardening metal powder in the capsule 1 which is compressed and sealed under a pressure of 0 to 1000 kg/car becomes an integrated sintered body 8. The multilayer sintered body 8 subjected to hot isostatic pressing is machined to the predetermined dimensions of the track bushing in this embodiment, and then the inner and outer diameter surfaces are simultaneously hardened. For quenching, oil quenching, water quenching, or high-pressure water spray quenching can be applied. FIG. 4 shows the state of high-pressure water spray hardening. This high-pressure water spray quenching heats and maintains a predetermined temperature and then produces 2 kg/cI+! By applying the above-mentioned high-pressure water spray 9, it is possible to perform stable hardening on each part, and is a suitable means for obtaining a highly accurate track bushing 1o.

At the same time, in the multilayer sintered body 8 in which the deep-hardening metal powder 2 and the shallow-hardening metal powder 3 are integrated, a shallow hardening layer is obtained on the second surface side during quenching, resulting in a deep hardening layer and a shallow hardening layer. A base layer having low hardness and high toughness can remain between the two layers.

Next, examples will be described in which various types of metal powder materials are used as the deep-hardening metal powder and the shallow-hardening metal powder, and the quenching treatment is performed by high-pressure water spray quenching, oil quenching, or water quenching. As shown in Table 1, the desired function was obtained, and the first surface in particular had a Vickers hardness (Hv) of 700 or more (Rockwell surface hardness: 6).
0 or more) was ensured.

Example 1 - Using medium carbon steel powder with a carbon content of 0.50% or more, Mn
, Cr, and Si were used to adjust the hardenability (Di value). The first surface side (outer diameter side, same below) is medium carbon steel 555C
The powder was adjusted to a Di value of 1.8, and the second surface side (inner diameter side, same hereinafter) was adjusted to a Di value of 0.77 using medium carbon steel 555C powder, and after forming a multilayer sintered body, high pressure water spray was applied. Hardened by hardening method.

Example 2 - Medium carbon steel 555C powder was adjusted to a Di value of 1.8 on the first surface side, and medium carbon steel 545C powder was adjusted to a Dl value of 0.77 on the second surface side, and a multilayer sintered body After that, it was quenched using a high-pressure water spray quenching method.

Example 3 - Tools on the first side! Aiming to obtain high hardness (Rockwell surface hardness of 64 degrees) by using l5KS3 powder due to carbide precipitation, the second surface side is made of medium carbon steel 545C powder with a Di value of 0.
．． 77, and after forming a multi-layer sintered body, it was quenched by an oil quenching method.

Example 4 Tool steel 5KS3 powder was used on the first side as in Example 3, and medium carbon steel 555C powder adjusted to a Di value of 0.77 was used on the second side. After that, it was quenched using an oil quenching method.

Example 5 A multilayer sintered body was made using the same material combination as in Example 3, and then water quenched.

Example 6 The same material combination as in Example 4 was used, and a multi-layer sintered body was made, followed by water quenching.

In each of Examples 1 to 6 above, the filling thickness of the metal powder material into the capsule was 17 mm, the thickness of the deep hardening metal powder part on the first surface side was 7 +nl11, and the thickness of the deep hardening metal powder part on the second surface side was 17 mm. The thickness of the shallow hardening metal powder portion was arranged in order of 10.

As for the track bushing of Example 1 described above as a mechanical component of the present invention, the formation state of the hardened layer on the first surface side, which is the outer diameter side, and the second surface side, which is the inner diameter side, is shown in FIG. It is shown. According to this, a deep hardened layer is formed on the outer diameter side of the cylindrical track bushing, and the hardened layer on the inner diameter side is much shallower than that on the outer diameter side. What is particularly noteworthy from the distribution state of the hardened layer shown in FIG. 5 is the Vickers hardness (Hv) of the surface hardness on the outer and inner diameter surfaces.
Even though the hardness is over 700, the intermediate layer sandwiched between the hardened layers on both sides retains a base layer with a Vickers hardness of about 300, and this structure distribution is also confirmed by the results of microscopic examination. It was done.

That is, what is shown in FIGS. 6 to 9 are photographs (magnification: 200 times) of the metal structure of the material corresponding to Example 6.

Figure 6 shows the surface area on the first side, and the hardness is Hv 800 to 8.
40. Figure 7 shows the boundary area between multiple layers, where the hardness on the first side (left half of the photo) is Hv 700-740, the hardness on the second side (right half of the photo) is Hv 470-550, and the hardness on the second side (right half of the photo) is Hv 470-550. Figure 8 shows the intermediate base layer, which has a hardness of Hv 350, and Figure 9 shows the surface area on the second side, which has a hardness of Hv 700 to 715.

The presence of such a matrix layer provides toughness and significantly improves the fatigue strength of the mechanical component. In particular, when applied to track bushings, cracks that occur from the inner diameter side, which is unique to track bushings, are stopped at this tough intermediate layer portion or the propagation speed of the cracks is suppressed.

Although the above description has been made regarding cylindrical mechanical parts, the same applies to annular plates such as thrust plates.

4... Deaeration port 5... HIP device 9... High pressure water spray 10... Track bushings Figures 1 to 4 are explanations for showing the configuration of specific embodiments of the present invention. FIG. 1 is an explanatory diagram of the filled state of metal powder material, FIG. 2 is an explanatory diagram of the degassed and sealed state, and FIG. 3 is an explanatory diagram of the state of the hot isostatic press (HIP device 5). The explanatory diagram and FIG. 4 are explanatory diagrams of high-pressure water spray hardening.

FIG. 5 is a diagram showing the distribution of metal structure in an example of the present invention.

FIGS. 6 to 9 are photographs showing metal structures in examples of the present invention, in which FIG. 6 shows the surface area on the first surface side, FIG. The figure shows the metal structure of the intermediate base layer, and FIG. 9 shows the metal structure of the surface area on the second surface side.

1...Capsule 6...Heater 2...
Deep hardening metal powder 7... Compressed gas 3... Shallow hardening metal powder 8... Sintered body Fig. 4 Fig. 3 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9

Claims (1)

[Claims] 1. A wear-resistant mechanical component having first and second wear-resistant surfaces facing each other, which is produced from a first metal powder material that has high quench hardness and can form a deep hardened layer. a metal part forming the first wear-resistant side, a metal part forming the second wear-resistant side produced from a second metal powder material that provides a shallow hardened layer, and the first wear-resistant side. 1. A wear-resistant mechanical component comprising a metal body having a multilayer structure having a metal base portion existing between a metal portion on a wear-resistant side and a metal portion on a second wear-resistant side. 2. In a wear-resistant mechanical component having a first and a second wear-resistant surface in a front-back relationship, a first metal powder material having high quench hardness and capable of forming a deep hardened layer on the first wear-resistant surface side. and a step of forming a multilayer structure of the first and second metal powder materials such that a second metal powder material that provides a shallow hardened layer is located on the second wear-resistant surface side; A step of sintering the formed multilayer structure of the first and second metal powder materials by hot isostatic pressing, and a quenching process of the sintered multilayer structure of the first and second metal powder materials. A method of manufacturing a wear-resistant mechanical part, comprising the steps of: 3. The method of manufacturing a wear-resistant mechanical component according to claim 2, wherein the hardening process is a high-pressure water spray hardening process. 4. The method of manufacturing a wear-resistant mechanical component according to claim 2, wherein the quenching step is an oil quenching step. 5. The method of manufacturing a wear-resistant mechanical component according to claim 2, wherein the quenching step is a water quenching step.