JPS5914537B2 - Sintered sliding parts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sliding member manufactured by powder metallurgy that has excellent wear resistance and oxidation resistance at high temperatures.

Sintered alloys have excellent composite properties, and in addition to dispersing hard components with high wear resistance, it is possible to simultaneously contain low melting point metals and components with high lubricity such as sulfur compounds, thereby improving the wear and sliding properties. It is.

Based on this idea, the present invention aims to provide a sliding material that is inexpensive and has excellent wear resistance. 8 to 30%, Mo or Fe-Mo powder at Mo% of 0.
Add 2% to 5% of Cu2S or W2S to 5 to 15φ, carbon powder of 0.1 to 2.0 mm, and a small amount of mold lubricant, mix and press mold in a reducing atmosphere at 1000 to 1150°C. Obtained by sintering.

Cr in the component dissolves in iron and improves the heat resistance and oxidation resistance of the matrix. When it coexists with C, it partially precipitates as carbide and helps improve wear resistance. If it is less than 8%, these effects are not sufficient. Moreover, if it exceeds 30%, the material becomes brittle and workability decreases, so the preferred composition range is set to 8 to 30%.

Addition of Mo is effective in improving heat resistance and oxidation resistance in Fe-Cr systems, but if it is less than 0.2%, the effect is small, and if it is more than 5%, workability deteriorates.

When C is added to this system, the matrix becomes a martensitic structure, which hardens significantly and improves wear resistance and heat resistance.If C is less than 0.1%, there is almost no effect, but if it is more than 2%, carbide formation occurs. is precipitated in a network and becomes brittle, so the quantity is 0.
A range of 1 to 2 is preferable.

Cu25-WS2 is added as a lubricating component in this system.

It is generally known that sulfur or sulfur compounds exhibit lubricity, but actually obtaining a sintered body containing these compounds is difficult because these compounds easily decompose in a reducing atmosphere, impairing sintering. So it's quite difficult.

Among many sulfur compounds, cuprous sulfide (Cu2S)
and tungsten sulfide are stable up to relatively high temperatures (melting point of cuprous sulfide → stable up to 1130℃ 1130℃ tungsten sulfide ℃), and if the sintering temperature is 1000 to 1150℃, these sulfur compounds will remain stable even after sintering. It remains in the sintered body in almost perfect form.

The function as a lubricating component cannot be said to be sufficient if the addition ratio is less than 5%, and even if it exceeds 15%, there will be a significant decrease in strength.
It is preferable to add in a range of 15%.

This will be described in detail in Examples below.

<Example> 1325 mesh chromium or ferrochrome powder,
Molybdenum or ferromolybdenum powder of the same <-325 mesh, graphite powder, Cu2S, WS2 powder, and iron powder of -100 mesh were mixed in the following composition ratio, and after mixing, molded to a density of 85%, and then heated at 1230°C for 1 hour. Sintering (in hydrogen atmosphere) was performed.

A high-temperature wear test was conducted on the obtained sintered material.

Fe12, phosphor bronze, sintered alloy Fe-0,
3P-5Mo-I C-3P b were selected and tested at the same time.

As is clear from the above results, sintered materials with ferritic and martensitic compositions containing cuprous sulfide or tungsten sulfide as a self-lubricating component are better suited to cast iron and phosphor bronze, which are well known as materials with excellent wear resistance. Moreover, it exhibited wear resistance and seizure resistance at high temperatures and in an oxidizing atmosphere that exceeded that of sintered alloys containing lead components.

This is thought to be due to the fact that the material of the present invention is composed of a sulfur compound that exhibits excellent lubricity over a wide temperature range from room temperature to relatively high temperatures. .

Claims (1)

[Claims] 1. Cr: 8 to 30% by weight, Cu2S or WS2:
Sintered sliding member 2 consisting of a composition of 5 to 15% and remaining iron; Cr by weight: 8 to 30%, Mo: 0.2 to 5
%, Cu2S or WS2: 5-15%, remaining iron composition Sintered sliding member 3 Weight: Cr: 8-30%, Mo: 0.2-5
C: 0.1-2.0%, Cu2S or WS2: 5
Sintered sliding member consisting of ~15% residual iron composition