JPS61104048A - Sliding member and manufacture thereof - Google Patents

Abstract

PURPOSE:To manufacture a sliding member of sintered alloy having superior wear resistance and strength, by infiltrating lead into the sliding part requiring wear resistance and by infiltrating copper into the matrix part requiring strength, respectively, of a sintered alloy. CONSTITUTION:Lead grains 6 are placed on a graphite tray 7, a ring 4 of sintered body is put upon the lead grains 6 with its sliding part undermost, upon which a copper powder-molded substance 5 is placed. Succeedingly, the above material is heated in an atmosphere of AX gas to infiltrate lead and copper, respectively. In this way, a valve sheet ring which has a sliding surface 1 having a lead-infiltrated part 2 at the sliding part requiring wear resistance and having a copper-infiltrated part 3 at the matrix part requiring strength can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sintered alloy sliding member used in internal combustion engines and the like, and a method for manufacturing the same.

[Prior art]

In sliding members such as valve seats of internal combustion engines, the sliding parts are required to have wear resistance, and the base material parts are required to have high strength. Since there are few materials that have both of these properties, conventionally, sintered alloys have generally been infiltrated with copper or lead. Therefore, lead infiltrated materials with lubricity are preferred for wear resistance, while copper infiltrated materials are often superior in terms of strength. Conventionally, when trying to obtain a member with good lubricity, the strength is inferior, and when trying to obtain a member with excellent strength, the desired lubrication performance cannot be obtained. Therefore, there has been a need for a sliding member that satisfies both requirements for excellent wear resistance and high strength in a single member.

[Purpose of the invention]

The present invention is intended to meet the above-mentioned conventional demands, and has excellent wear resistance by infiltrating the sliding parts with lead, and improved strength by infiltrating the base material part with copper. It is an object of the present invention to provide an excellent composite infiltrated and sintered alloy sliding member, as well as a method for manufacturing the sliding member.

[Structure of the invention]

In the composite infiltrated sintered alloy sliding member of the present invention, lead or lead alloy with excellent wear resistance is infiltrated into the sliding parts of the sintered alloy base material that require wear resistance, and It is characterized by having steel or copper alloy with excellent strength infiltrated into the parts of the base material that require full strength.

The composite infiltrated and sintered alloy sliding member of the present invention is manufactured by infiltrating the sliding portion with lead or a lead alloy, and infiltrating the base material portion with copper or a copper alloy.

This composite infiltrated and sintered alloy sliding member is used in internal combustion engines.

Can also be used for valve seat rings.

The present invention will be explained in detail below.

The skeleton may be a molded body, a pre-sintered body, or a sintered body of metal powder, and the skeleton may be a single-layer body made of metal powder with the same composition for both the sliding part and the base part, or It may also be a multi-layered body made of metal powders with different compositions. The sliding part side of the skeleton may be placed facing downward, and lead or a lead alloy may be brought into contact with the lower surface of the skeleton, and copper or a copper alloy may be brought into contact with the upper surface of the skeleton to perform heat infiltration. In the infiltration process, lead or lead alloy is infiltrated into the sliding part by heating at a temperature higher than the melting point of copper or copper alloy and higher than the melting point of lead or lead alloy, and then heated in a pot or at a temperature higher than the melting point of copper alloy. Copper or copper alloy may be infiltrated into the substrate portion by heating at a temperature. In addition, first, copper or copper alloy is selectively infiltrated only into the base material part, and then lead or lead alloy is infiltrated into the sliding part at a temperature below the melting point of copper or copper alloy and above the melting point of lead or lead alloy. 0 To explain in more detail, the present invention is a composite infiltrated sintered alloy sliding member that has both the advantages of copper infiltration (high strength) and lead infiltration (wear resistance). By infiltrating copper into the pores, the strength level of the composite is maintained at a sufficiently higher level than by infiltration of lead alone, and by infiltrating the trapped lead into the pores of the sliding area, the wear resistance properties of the composite are improved. Since it acts as a lubricant, it is far superior to infiltration of copper alone, and provides superior properties that surpass infiltration of lead alone. The latter reason is thought to be mainly due to the improved thermal conductivity of copper in the base material compared to lead alone.The reason for placing the skeleton with lead in contact with the bottom surface of the skeleton and copper in contact with the top surface of the skeleton is This is to take advantage of the fact that the specific gravity of lead is greater than that of copper to actively dynamically segregate both in a liquid phase state.

In addition, the reason why the sliding parts are thoroughly infiltrated with lead or lead alloy and then the base material part is infiltrated with copper alloy is to ensure the wear-resistant properties of the sliding parts. .

In the manufacturing method of selective infiltration and composite infiltration, it is necessary to use an iron-based skeleton and selectively infiltrate only the base material portion with copper or copper alloy in the first step of infiltration. As a means of achieving this, in order to avoid infiltration of copper or copper alloy into the sliding part, a matrix alloy containing elements such as chromium that is easily oxidized in the infiltration atmosphere is used for the sliding part material, and chromium is used in the infiltration atmosphere. RX with a high dew point such that surface oxides such as
By using a gas atmosphere or the like, oxides are formed on the surface and around the pores of the material of the sliding part, so that the wettability with the liquid phase of the copper or copper alloy infiltrant is poor, and infiltration of the sliding part can be prevented. On the other hand, since the base material does not contain elements such as chromium that are easily oxidized in the above-mentioned infiltration atmosphere, it does not form oxides that impair wettability even in the RX gas atmosphere, so infiltration of copper or copper alloy is ensured. It can be carried out.

Next, in the second step of infiltration, it is necessary to infiltrate the uninfiltrated sliding parts with lead or a lead alloy. As a means of achieving this, it is possible to remove lead or Infiltration of lead or lead alloys can be carried out, preferably at i = lower than the melting point of the copper or copper alloy.

〔Example〕

The present invention will be explained below using examples.

Example 1 IC1Mo powder, Co powder, graphite powder and Fe powder were blended so that MO was 10%, Co was 5%, 01% and the balance was Fe.For this reason, mold lubricant was added to 100 parts of the mixed powder (same weight of 2 or less). A sliding member powder obtained by adding and mixing 18 parts of C1
% and the balance is Fe, a base material powder made by adding and mixing 100 parts of moisture of graphite powder and iron powder with 8 parts of mold lubricant α, an outer diameter of 3 mm, an inner diameter of 20 mm,
7 ton valve seat ring shape with a height of 10 m.
/- was molded in two layers. This is in the t-AX dust atmosphere 1
Sintering was performed at 150°C for 60 minutes.

Next, as shown in FIG. 2, the sintered ring,
・Place 2 tons of lead grains (6) on a graphite tray with a groove to accommodate the sintered body (with the sliding part facing down).
4) on top of the lead grains (6), and on top of that a copper powder molded body (5) with an outer diameter of 50mm, an inner diameter of 204mm, and a height of 5m, and heated and melted in an AX gas atmosphere. Soaked. At that time, the composite melt as shown in Figure 1 was prepared by first holding the temperature at 1050°C, which is above the melting point of lead and below the melting point of copper, for 30 minutes, and then holding it at 1130°C, above the melting point of the pot, for 30 minutes. A sintered body (invention material 1-1) was obtained. In the figure, (2) is a lead or lead alloy infiltrated area, and (3) is a copper or copper alloy infiltrated area.

Thereafter, composite infiltrated sintered bodies having the components and compositions shown in Table 1 were obtained in the same manner. Inventive material 1-2 is not a sintered body like inventive material 1-1 as a skeleton to be infiltrated, but is
Using a pre-sintered body sintered for 0 minutes, copper infiltration was performed at 1150°C.
It was held for 60 minutes. Inventive material 1-5 uses a molded body as the skeleton to be infiltrated, and inventive material 1-2 in the infiltration process.
The same process followed. Inventive materials 1-4 and 1-5 used Co-based and Ni-based materials for the sliding parts, respectively. Comparative materials 1-1 and 1-2 were also obtained in the same manner as inventive material 1-1. Comparative material 1-1 was infiltrated with only lead, and comparative material 1-2 was infiltrated with only copper. The radial crushing strength was measured with these test pieces. In addition, a valve seat test was conducted and the increase in contact width was measured as valve seat wear.

In the present invention, "percentage" is O based on weight. The results are shown in Table 1. As can be seen from the results in Table 1, the present invention materials 1-1 to 1-5 all have a radial crushing strength of 100 Kf.
7.5 Kf of comparative material 1-1 infiltrated with lead alone at fl- or more
fl- width is excellent, and the width of the valve seat test seat is increased by 12
It was far more immersible than Comparative Material 1-2, which was infiltrated only with copper, at 1.17 m at 5 m or less, and was also superior to Comparative Material 1-1, which was infiltrated with only lead.

Example 2 Graphite powder (L5 parts and lubricant 0.8
Powder for sliding members made by adding and mixing 2% Ni, 2% G
A base material powder prepared by adding and mixing 8 parts of a mold lubricant to 100 parts of a powder consisting of 15% r[15% and the balance Fe, with an outer diameter of 30 parts,
A valve seat ring having an inner diameter of 20mm and a height of 101mm was molded in two layers with a mold at 7 ton/d. This was sintered at 1150° C. for 60 minutes in an AX gas atmosphere.

Next, set the sintered body on a graphite tray with the sliding part facing down, and place the sintered body on top of it with an outer diameter of 60 mm and an inner diameter of 20 m+.

A copper powder molded body having a height of 5 degrees was placed on it, and infiltration was carried out at 1120° C. for 30 minutes in a PX gas atmosphere. Next, lead particles were set on a graphite tray, and the above-mentioned infiltrated body was placed on top of it with the sliding part facing down, and infiltrated for 50 minutes at 1050°C in an H gas atmosphere to form a shape as shown in Figure 1. Composite infiltrated body (invention material 2-1)
I got it.

Thereafter, a composite infiltrated sintered body of invention material 2-2 was obtained in the same manner. In addition, for the sliding member, 100 parts of alloy powder consisting of 1 piece of Mo, 3 pieces of Cr, and the balance Fe, 2 parts of Ni powder, and α of Gr powder were added.
5 parts and mold lubricant α8 parts were added and mixed, and the base material was 100 parts of powder consisting of 3% Cu powder, Ni powder, Cr powder (18% and the balance Fe powder) and mold lubricant (18 parts). P is used as a lead infiltrant.
b -1chiSn1 As a copper infiltrant, Cu-(L5C
o-α3Fe was used. Also, in the same manner, comparative agent 2-
Obtained 1 and 2-2ft. Note that comparative material 2-1 is the invention material 2.
The sintered body of No.-1 was infiltrated with only lead in an H2 atmosphere. Comparative material 2-2 was obtained by infiltrating only copper into the sintered body of invention material 2-1 in an H2 atmosphere.

These test pieces were used to measure the total radial crushing strength, and after being processed into the shape of a valve seat test piece and combined with a 2l-4N/< loop, a valve seat test was conducted at 500°C for 10 hours. Width gain was measured.

The results are shown in Table 2. As can be seen from Table 2, the radial crushing strength is 115 Kgf/wj and 120 Kqf/, respectively.
It was superior to Comparative Material 2-1 infiltrated with lead alone in terms of d, and was almost equivalent to 120 Kff/H of Comparative Material 2-2 infiltrated with copper alone, which had excellent strength. Also, in the valve seat test, the width increase per valve seat wear was 143 mm or less, compared to the comparison material with copper infiltration alone? It was far superior to Comparative Material 2-1, which was infiltrated with lead alone, and had good abrasion resistance.

Table 2 [Effects of the invention] The present invention employs composite infiltration in which lead or lead alloy is infiltrated into the sliding parts that require wear resistance, and copper or copper alloy is infiltrated into the base material parts which require strength. 4. A sintered bond that combines both the wear resistance, which is an advantage of lead infiltration, and the excellent strength and roundness, which is an advantage of copper infiltration, which could not be obtained by conventional infiltration of lead or copper alone. A gold sliding member can be obtained.

In addition, in the present invention, the characteristics of the movable member can be easily changed over a wide range by appropriately adjusting the porosity of the sintered alloy serving as the base material and the respective infiltration amounts of lead and copper to be infiltrated. In addition, the composite GT lining method of the present invention, which takes advantage of the difference in skin and melting point between the steel and the lining, has many excellent effects such as the ability to perform lead infiltration and copper infiltration in the same process. This can be carried out in a simple manner, and furthermore, the base material portion is selectively immersed in 'At' bath, and the lead is infiltrated by infiltration. It can also be easily manufactured using the B method.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the structure of the valve seat ring of the present invention. FIG. 2 is a cross-sectional view showing how to set the sintered body in the infiltration process. In figure 1. 1... Sliding surface with pulp 2... Lead or lead alloy infiltration area 3... Copper or copper alloy infiltration area 4... Sintered body ring 5... Copper or steel alloy infiltrant (Molded object) 6... Lead or lead alloy infiltrant (granules) 7... Graphite tray patent applicant Toyota Motor Corporation Fig. 1 Fig. 2

Claims (8)

[Claims] (1) Lead or lead alloy is infiltrated into the sliding parts of the base material sintered alloy that require wear resistance, and copper or copper alloy is infiltrated into the base material parts that require strength. A composite infiltrated and sintered alloy sliding member characterized by: (2) The composite infiltrated and sintered alloy sliding member according to claim 1, which is a valve seat ring for an internal combustion engine. (3) Using a metal powder compact, pre-sintered body, or sintered body as a skeleton, infiltrating the sliding parts of the skeleton with lead or a lead alloy, and infiltrating the base material part with copper or a copper alloy. A method for manufacturing a composite infiltrated and sintered alloy sliding member. (4) The manufacturing method according to claim 3, wherein the skeleton is a single layer body made of metal powder having the same composition in both the sliding portion and the base material portion. (5) The manufacturing method according to claim 3, wherein the skeleton is a multi-layered body in which the sliding portion and the base material portion are made of metal powders having different compositions. (6) Place the skeleton with the sliding part side facing downward,
4. The manufacturing method according to claim 3, wherein the lower surface of the skeleton is brought into contact with lead or a lead alloy, and the upper surface of the skeleton is brought into contact with copper or a copper alloy for heating. (7) Infiltrate the sliding parts with lead or lead alloy by heating at a temperature below the melting point of copper or copper alloy and above the melting point of lead or lead alloy, and then at a temperature above the melting point of copper or copper alloy. 4. The manufacturing method according to claim 3, which comprises infiltrating copper or copper alloy into the base material portion by heating. (8) Copper or copper alloy is selectively infiltrated only into the base material portion, and then lead or lead alloy is infiltrated into the sliding portion at a temperature below the melting point of the copper or copper alloy. The manufacturing method described in Section 3.