JPS5823463B2 - High temperature sliding parts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a material used for continuous or intermittent sliding parts at high temperatures, and is widely used for sliding parts of internal combustion engines, heating furnaces, hot rolling equipment, etc. It provides materials.

More specifically, the present invention aims to provide a material suitable as a bearing material for supporting a butterfly valve shaft in an internal combustion engine.

This bearing is installed in an exhaust manifold that changes the flow of exhaust gas depending on the engine temperature.

That is, when the engine is cold (when starting), the manifold valve closes and allows exhaust gas to flow into the intake manifold path.

This high-temperature gas warms the inhaled fuel mixture gas and causes complete fuel vaporization during warm-up.

When the engine warms up, the butterfly valve opens and exhaust gas is discharged through a steady path.

Since the exhaust gas temperature is around 700-800℃,
Seizure and oxidation occurred on the surface of the valve's rotating shaft and bearing, causing the valve to not rotate smoothly.

Conventionally, commonly used heat-resistant materials include superalloys, stellite alloys, and stainless steels made by melting, but these are unsatisfactory because they cause seizure in bearings that slide intermittently at high temperatures, such as this bearing. It turns out that.

Furthermore, copper-based oil-impregnated bearings made by conventional powder metallurgy methods and similar materials have problems with heat resistance and do not satisfy the usage conditions.

Conventional heat-resistant alloys and bearing materials cannot meet the requirements for such intermittent sliding materials used in oxidizing atmospheres at high temperatures, and it has been necessary to develop new alloys.

The object of the present invention is thus to provide an inexpensive alloy that satisfies the performance as a versatile high-temperature sliding member, including high-temperature bearings, and its contents will be described below.

The alloy composition is Cr15-35, Ni
Or Mn8-40%, Mo0.1-6%, Cu3
~30%, C0.1~2%, Pb 0.2~15 parts, low melting point glass 0.5~8 parts, balance Fe, porosity 0
．． 5-30%.

Example 1 Iron powder (-100mesh), Fe-Cr master alloy powder (-
325mesh), copper powder (electrolytic), Ni powder, ferromanganese powder, molybdenum powder, graphite powder, lead, and low melting point glass powder were mixed into the composition shown in Table 1, and these mixed powders were mixed at 6t/d. After molding, sintering was performed at 1200°C in ammonia decomposition gas.

Some of these sintered bodies were further heated to 100% in nitrogen gas.
After heating at 0° C., the material was subjected to pressure treatment to obtain a high-density sintered body with a porosity of 5% or less.

Example 2 Fe-20%Cr-10%Ni blended in Example 1
Co powder and W powder are added and mixed to the mixed powder of -1,5%Mo-5%Cu-1%C-5%Pb-2 low melting point glass composition to form the composition shown in Table 1. And these powders are 6t/cr? After molding with L, sintering was performed at 1200°C in ammonia decomposition gas.

Some of these sintered bodies were further heated to 100% in nitrogen gas.
After heating at 0°C, the material was subjected to pressure treatment to obtain a high-density sintered body with a porosity of 5 or less.

Example 3 To the mixed powder prepared in Examples 1 and 2, Bi, Sb, Sn, and l' were added as low melting point metal powders, and S2MoS2. WS2 was added and mixed, and the above-described molding, sintering, and hot pressing treatments were performed to obtain the sintered bodies shown in Table 1.

Of the sintered bodies thus obtained, the seven types of samples shown in Table 2 and the comparative material were processed into a bearing shape, and an opening/closing experiment of a butterfly valve was conducted.

The experimental conditions are as follows.

(1) Bearing shape = 10φ x 6φ x 25mm (2) Butterfly shaft material: Niostenitic stainless steel (3) Swivel angle: 0 to 100° (4) Swivel speed: 3/rn 1 n (5) Heating cycle: Drawing However, as shown in , A = 0.5 Hr B = 2 Hr C = 0.5 Hr D = 1.0 Hr (6) Atmosphere = 10 ratio H20 air (7) Housing: Cast iron When smooth operation becomes difficult ( dynamic torque is 1
(equivalent to 0 kgvtm or more) was taken as the durability time.

The results of this durability experiment are shown in Table 2. Hardness of comparison materials: 316 Stainless steel RB80-90 Niresist 80-90 Sintered material (I) 75-85 As is clear from these results, the invention material did not cause seizure despite severe sliding conditions. Ta.

Next, the functions and compositions of the constituent elements of the member of the present invention will be explained.

Ni or Mn: 8-40 section It forms a solid solution in iron and promotes austenitization.

If the ratio is less than 8, the austenitization is insufficient, and if it exceeds 40, there is no effect and the price becomes high.

Mo: 0.1 to 6 and 7 solid solution in Trix to improve heat resistance and oxidation resistance,
If it is less than 0.1%, the effect is insufficient, and if it is more than 6%, it becomes brittle.

Cu: 3 to 30 In addition to being solid dissolved in the steel and helping to improve corrosion resistance, undissolved copper turns into copper oxide during sliding, contributing to improving seizure resistance, and also improves thermal conductivity and dissipates heat. It is useful for adjusting the properties and coefficient of thermal expansion.
When the ratio is 3 or less, the effect is small, and when it is 30 or more, the strength decreases greatly.

C: 0.2 to 2 C is incorporated in iron to improve the strength of the matrix and at the same time forms carbides, contributing to the improvement of wear resistance, but if it is less than 0.2, it is insufficient, and if it is more than In this case, the amount of net-like carbide increases and the strength decreases.

Pb: 0.2 to 15%) IJ Lux does not form a solid solution and acts as a lubricating component in the temperature range from room temperature to 300 to 400°C where it exists within the voids of the sintered body and prevents seizure.

If the ratio is less than 0.2, there is no effect, and if it is more than 15, the strength will decrease significantly.

A low-melting glass whose main constituents are P2O5, B2O3, PbO, K2O, and Na2O and has a softening point around 300°C.

It acts as a lubricating component in the temperature range of 300°C or higher, but
If the ratio is less than 0.5, the lubrication function is insufficient, and if it is more than 8, the strength will be significantly reduced.

Co: 1 to 15 Co dissolves solidly in the matrix and contributes to improving heat resistance;
If the ratio is less than 15, the effect will be small, and if it is 15 or more, the strength will decrease significantly.

Cr:W: 1 to 15% Solid solution in the matrix improves heat resistance and oxidation resistance, and at the same time helps to partially improve wear resistance, but below 1%, these effects are small, and above 15% Workability is significantly reduced.

The porosity of the material of the present invention is suitably in the range of 0.5 to 30.

That is, when oxides generated during high-temperature sliding and foreign matter deposited from the surrounding atmosphere adhere to the sliding surface, these deposits are buried in the surface pores to prevent abrasive wear. Oxides such as Pb and Mo are effective in improving seizure resistance.

If the porosity is less than 0.5, there is no effect, and if the porosity is more than 30, the strength of the material will decrease significantly.

In the examples, the powder mixing method was used, but it goes without saying that Cu, Pb glass, solid lubricants, etc. may be impregnated and added.

[Brief explanation of the drawing]

The drawing is a chart showing heating cycle conditions in durability tests of members of the present invention.

Claims (1)

[Claims] 1 Cr: 15-35%, Ni or Mn: 8-4% by weight
0 ratio, Mo0.1-6%, Cu3-30%, C0.1-
2 parts, Pb 0.2~15 parts, and low melting point glass 0.5~
A high-temperature sliding member made of a sintered composite material having a composition of 8 parts, the balance being Fe, and a porosity of 0.5 to 30 parts. 2 Cr15-35%, Ni or Mn8-4 in weight ratio
0%, Mo0.1-6%, Cu3-30%, C0.1-
2 parts, Pb 0.2 to 15 parts, low melting point glass 0.5 to 8%
, and Co, one or two types 1 to 15 of W, the remainder Fe
A high-temperature sliding member made of a sintered composite material having a composition of 0.5 to 30 and a porosity of 0.5 to 30. 3 Cr15-35%, Ni or Mn8-4 in weight ratio
0%, Mo0.1-6%, Cu3-30, C061-
2 parts, Pb 0.2 to 15 parts, low melting point glass 0.5 to 8 parts, and Bi of Ag or low melting point metal. 0.5-5% of one or more of Sb and Sn, balance F
A high-temperature sliding member made of a sintered composite material having a composition of e and a porosity of 0.5 to 30. 4 Cr15-35%, Ni or Mn8-4 in weight ratio
0 ratio, Mo0.1~6%, Cu3~30%, co, i~
2 parts, PbO, 2 to 15 parts, low melting point glass 0.5 to 8%
, and S, MoS2 as solid lubricants. One or more types of WS2 0. ．． 5-5%, balance Fe
A high-temperature sliding member made of a sintered composite material having a composition of 0.5 to 30 and a porosity of 0.5 to 30.