JPS60155650A - Sliding member for power machine - Google Patents

Abstract

PURPOSE:To produce a sliding member for a power machine having excellent durability even if the member is slid under high pressure by sintering a powdery and granular raw material such as steel or cast iron contg. Cr at a relatively low temp. to form a sintered body having sintered holes of a specific size and volume. CONSTITUTION:0.1-5.0% 1 or >=2 kinds P, B and Si which permits liquid phase sintering at <=1,250 deg.C are mixed with a powdery and granular material such as steel or cast iron contg. 0.5-4.0% C and 8-30% Cr. The mixture is sintered at relatively low temp. of <=1,250 deg.C to produce a sintered sliding member. Or <=10% 1 kind of Ni, Cu, Co and W or <=20% Mo or <=20% at least >=2 kinds among Ni, Mo, Cu, Co and W are mixed therewith and the mixture is sintered. Holes in which the holes having <=150mu size occupy >=40% of the entire part are formed at 0.2-10vol% in the sintered body. The sintered sliding member for a power machine having excellent durability when used for the part sliding under high pressure is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sliding member for power machine building materials, and more specifically, it was developed as a sliding member for high surface pressure power machines (hereinafter referred to as sliding member) used in internal combustion engines, compressors, etc. It is a sliding member that has sufficient durability even when exposed to high blood pressure.

Generally, sintered alloy materials for sliding members are often used for low blood pressure, and there are quite a few materials that can be used for high blood pressure. The sliding member of the present invention can be used for internal combustion engines and as a member for the sliding surface of a rocker arm, but its use is not limited thereto.

The rocker arm of an overhead camshaft type internal combustion engine is made of Stj iron, and the sliding surface with the cam of the camshaft is chilled, the sliding surface is chrome plated, or the sliding surface is coated with a self-fusing alloy spray coating. However, there are still many problems with durability because the sliding surface of this rocker arm causes high blood pressure.

The present invention was achieved based on these facts and as a result of diligent efforts to develop an excellent rolling member for high-face slings.

In addition to iron, the sliding member of the present invention contains 0.5 to 4.0% by weight of carbon, 8.0 to 30.0% by weight of chromium, and further contains 1.2% by weight of chromium.
0.1 to 5.0% of one or more of phosphorus, boron, and silicon that performs liquid phase sintering at 50°C or lower
, and has sintered pores of 0.2 to 10% by volume, and is characterized in that pores of which the size of the pores is 150μ or less account for 40% or more of the total, Zarani again,
In addition to the elements of phosphorus, boron, and silicon that perform liquid phase sintering, it further contains 10% by weight or less of any one of the metals Ni, Cu, Go, and W, or
Contains 20% by weight or less of O, or also ■Ni,
Mo.

Contains at least two kinds of metals C1l, CO, and W, and 20% by weight or less, has the same sintered pores as above, and has the same 1 metal.
It is characterized in that pores of 507 or less occupy 40% or more of the total.

The effects of each component in the sliding member of the present invention and the reason for limiting the amount of each component will be described below.

Carbon is an element necessary to strengthen the matrix, produce a precipitated hard phase (carbide of Cr containing Fe), and provide wear resistance. The reasons for limiting carbon as an alloy component are as follows. 0
．． If it is less than 5w%, the precipitated hard phase m is insufficient and cannot withstand wear under high load. Further, a high-strength base cannot be obtained, and if it exceeds 4.0% by weight, many hard particles precipitate and grow large, resulting in embrittlement. Moreover, the number of pores increases, resulting in a decrease in strength.

Sliding members used in high blood pressure tend to cause pitting, and pitting is a fatigue phenomenon caused by repeated loads received during sliding, and sliding members made of sintered alloy made by normal solid phase sintering have many pores. , easy to fatigue due to low strength,
Pitting wear is likely to occur due to repeated loads. A sintered alloy sliding member for use in hypertension is made by liquid phase sintering to improve pitting resistance. Liquid phase sintering is possible by sintering at a higher temperature, but due to the durability of the sintering furnace, it is necessary to generate a sufficient liquid phase at a temperature below 1.250°C. Phosphorus, boron, silicon, etc. are elements that allow liquid phase sintering to occur at temperatures below 1,250'C, so they are effective; if the amount of liquid phase is too small, no improvement in strength can be obtained; When the number of phases becomes too large,
A sintered body with high dimensional accuracy cannot be obtained.

Therefore, based on the above-mentioned reason, one or more of phosphorus, boron, and silicon is used in a mold open percentage range of 0.1 to 5.0%. The amount added and the sintering temperature have an inversely proportional relationship.

Cr is an important element for strengthening the matrix and forming a precipitated hard phase by combining with carbon. If the Cr content is less than 8% (1%), the suspension of the precipitated hard phase is insufficient. Also, 30
If the weight exceeds J%, no significant improvement in abrasion resistance will be observed, leading to a needless increase in price.Furthermore, the stiffness will deteriorate.

Note that the wear-resistant sintered alloy of the present invention does not specifically add Mn, but since iron powder is used as a raw material and the iron powder contains Mn as an impurity, naturally the wear-resistant sintered alloy of the present invention does not have Mn added. The sintered alloy also contains MO as an impurity.

Regarding porosity, if the porosity exceeds 10% by volume, sintering will be insufficient, the interparticle bonding strength will be weak, and fatigue fracture will easily occur, easily inducing pitting wear, and mechanical strength will also deteriorate, so 10% by volume Limited to the following.

Moreover, if it is less than 0.2% by volume, oil-tightness will be low, resulting in poor oil retention and prone to scuff wear. The importance of pores is clear from the fact that the expected performance could not be obtained with material 1 dissolved with the same components. It is desirable that the pores be fine and uniformly dispersed; if the pore size exceeds 150μ and the porosity is 10% by volume without vortex, the pores will be unevenly distributed and the oil retention will be very poor. This will result in deterioration. Therefore, for the same reason, if the proportion of fine pores of 150 μm or less is 40% or more, scuff wear is likely to occur.

For the above reasons, the sliding member of the present invention has no carbon content other than iron.
5 to 4.0% by weight, 8.0 to 30.0% by weight of chromium, and further contains one or more of phosphorus, boron, and silicon that perform liquid phase sintering at a temperature below 1,250°C. 0.1
-5.0% by weight, has sintered pores of 0.2 to 10% by volume, and 40% or more of the pores have a size of 150μ or less. The phosphorus, boron,
In addition to the silicon element, ■Ni, Cu, GO,
Contains 10% or less of any one of the metals W, or 20% or less of MO, or at least 2 of the metals Ni, Mo, Cu, Co, and W. It must contain at least 20% by weight of seeds, have sintered pores as described above, and have similar pores of 150 μm or less accounting for 40% or more of the total.

In the present invention, after sintering, it is possible to strengthen the base I'l weave by using a mating sliding member that is mainly made of pearlite, but is used in combination. As a method of strengthening the base structure, heat treatment can be performed after sintering to form a structure mainly of bainite or martensite. In this case, pitting resistance is further improved. For example, after sintering 87
After heating to 0℃, about 400℃ crane 1 to about 10 to 4 in a bath.
When heat treated for 0 hours, base 11 weave becomes bainite.

Further, if the base structure is heated to 870° C. and then heat-treated with water or oil at room temperature, the base structure becomes martensite.

Another way to strengthen base organization is Ni.

It is to add and contain MO, C1l, CO, W, etc. Ni, Mo, Cu, Co, and W may be added alone or in combination of two or more. N1゜Cu, Co', W
When added alone, 10% by weight or less is sufficient. The purpose of reinforcing the base structure can be fully achieved with Ni, Cu, and Co each at 10% by weight or less, and it is also 1 in terms of economic efficiency.
Advantageously, it is less than 0%. When W is contained in an amount of 10% by weight or more and used in combination with other sliding members, it tends to promote wear of the other sliding member. Therefore, the purpose of reinforcing the matrix structure can be achieved with a content of 10% by weight or less.

When Mo is added alone, 20 M@% or less is sufficient. If the content is 20% by weight or more and it is used in combination with a sliding member, the wear of the mating sliding member will increase. Further, from the economic point of view, it is advantageous for MO to be 20% by weight or less. Also, Ni, Mo.

When two or more types of Cu, Co, and W are added and contained, the purpose of reinforcing the matrix structure can be sufficiently achieved when the total of the two or more types of alloying elements is 20% by weight or less, and from the point of view of economic efficiency, 20% or less of alloying elements is required. It's advantageous. Even when alloying elements are added, base 11fi! As a method of strengthening i, the objective can also be achieved by performing heat treatment after sintering as described above.

The sliding member of the present invention precipitates a hard phase by adding Cr!
, P, B, and StW are added to liquid-phase sintering to form a high-density stone, and it has excellent pitting resistance and extremely good wear resistance.

The sliding member of the present invention was manufactured as a sliding member of a rocker arm, and a bench test was conducted using an internal combustion engine.

Example Raw material powder was blended with the target components shown in Table 1, and 5L/ct
After molding at a pressure of J, sintering was performed in an ammonia decomposition gas for 45 minutes to obtain sliding members N011 to N'O', 9 of the present invention.

Comparative material No. 10 is a spinning steel rocker arm in which a cooling metal is installed on the sliding surface of the cam in the mold, and the sliding surface is made into a delta by pouring the molten metal.

Engine test ■ Driving condition test a! Seki Water-cooled in-line 4-cylinder 0. H, C engine rotation speed 75Or, ρ, 111. No-load lubricant SAE
30# Oil temperature 50℃ Operating time 200 hr ■Sample camshaft The base of the cam part of the sample camshaft is made of pearlite.
Dell cast iron containing ~45% by weight carbide and has the following chemical composition:

The test results are shown in Figure 1. In FIG. 1, a bar graph with diagonal lines indicates the amount of wear on the cam, and a bar graph with no diagonal lines indicates the amount of wear on the rocker arm.

In this way, the sliding member of the present invention is made by precipitating a hard phase by adding Cr and sintering it in a liquid phase by adding P, B, Si, etc. to make it highly dense and thin. It is a material with excellent properties, and as is clear from FIG. 1, the wear amount is about 1/3 to 115 times lower than that of the sea urchin comparative example.

The sliding members NO61 to N009 of the present invention are pitchin'
There was no wear and tear.

FIG. 2 1 1, l1fl of the sliding part 14N0.7 of the present invention
This is a micrograph of the fabric (200x, corrosion), and the white hue is F.
It is a carbide made of e-Cr and Steady 1-, and the surrounding base of the white hue is pearlite.

Figure 3 shows a photograph of 71 pieces 5 of 11 textures (200 degrees, corrosion) of the dynamic member No. Yes, there is a white 4n round 01 base (J Behnai 1~).

[Brief explanation of drawings]

FIG. 1 is a graph showing the amount of i4 wear when the wear-resistant sintered alloy of the present invention was made into a rocker arm and an engine test was conducted. FIGS. 2 and 3 show microscopic photographs of an embodiment of the sliding member of the present invention. Figure 1

Claims (4)

[Claims] (1) Carbon 0.5 to 4. -ff1%, chromium 8.0 to 30.0% by weight, and 0.1 to 5% of one or more of phosphorus, boron, and silicon, which perform liquid phase sintering at 1,250°C or less. .0 including quantitative %, 0
．． 1. A driving member for power machinery made of wear-resistant sintered alloy, which has sintered pores of 2 to 10% by volume, and 40% or more of the pores are 150μ or less in size. . (2) In addition to iron, it contains 0.5 to 4.0% by weight of carbon, 8.0 to 30.0% of carbon, and an additional 1.25% of carbon.
Contains 0.1 to 5.0% by weight of one or more of phosphorus, boron, and silicon that perform liquid phase sintering at temperatures below 0°C, and further contains any of the metals Ni, CU, CO, and W. Contains 10% by weight or less of one of the above, has 0.2 to 10% of sintered pores, and 40% or more of the total pores have a size of 150μ or less A sliding member for a power machine made of a wear-resistant sintered alloy according to claim 1, characterized in that: (3) In addition to iron, carbon 0.5-4.0% by weight, chromium 8
．． 0 to 30.0m9%, and further contains 0.1 to 5.0% by weight of one or more of phosphorus, boron, and silicon that perform liquid phase sintering at 1,250'C or less,
Contains MO of 20% or less, 0.2 to 10 volume M
% of sintered pores, and the pores have a size of 1501 to C' or less, and the pores account for 40% or more of the total. 1. Movement member for power machinery made of sintered alloy. (4) In addition to iron, carbon 0.5 to 4.0% by weight, chromium 8
, 0-30. Among phosphorus, boron, and silicon, which include Oll hangers and undergo liquid phase sintering at temperatures below 1,250°C.
1 scale; or containing 0.1 to 5.0 m % of two or more species,
Furthermore, it contains at least two kinds of metals such as Ni, Mo, Cu, Co, and W, up to 20% by weight, and has sintered pores of 0.2 to 10% by volume, and the size of the pores is A sliding part for a power machine made of a wear-resistant sintered alloy according to claim 1, characterized in that pores having a size of 150 μm or less account for 40% or more of the total volume.