JPS58117896A - Sliding member - Google Patents

Abstract

PURPOSE:To obtain a sliding member which has excellent wear resistance when the member contacts with a mating member at a high speed by providing a dispersed iron plating layer of silicon carbide wherein silicon carbide of a prescribed grain size range is dispersed at specific ratios on the sliding surface of a base material made of iron or steel and forming a nitride layer on the surface of said plating layer. CONSTITUTION:Silicon dispersed iron plating is carried out on at least sliding surface of a base material made of iron or steel in an iron plating bath wherein silicon carbide particles of 0.5-3.0mu average grain size are suspended. The surface of the silicon dispersed iron plating layer is nitrided to form a nitriding layer, whereby the intended sliding member is obtained. The dispersing ratio of the silicon carbide particles in the above-described silicon carbide dispersed plating layer is regulated at 5-30% by volume. The nitriding may be by any of gas nitriding, gas soft nitriding and ion nitriding method. Iron and steel materials to be used usually as materials for sliding parts such as piston rings are used for the base material.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sliding member, and more specifically, to a sliding member that has an improved surface treatment and has excellent wear resistance, which moves at high speed without contacting a mating member. .

For example, piston rings that slide at high speed on cylinders or cylinder liners due to the vertical movement of the piston are required to have wear resistance, and piston rings whose outer peripheral sliding surfaces are plated with hard chrome have been widely used. It is well known that a hard chrome plating layer has excellent wear resistance, but the plating process takes a long time, and measures to prevent pollution from plating waste liquid are expensive, making plating difficult. Cos F
There is a problem that the amount of water increases. Surface treatments other than hard chrome plating include dispersion plating, in which hard particles such as silicon carbide are dispersed in iron, cobalt, or nickel, which belong to group JA of the periodic table, and molybdenum thermal spraying, which improves initial conformability. It has been adopted in some cases.

Piston rings with these conventional surface treatments all have excellent wear resistance, but in gasoline engines that use high-lead gasoline as fuel, the piston rings wear a lot, and the next generation of the engine The cycle of the overhaul salt period, the so-called release period, becomes faster.

The purpose of the present invention is to provide a sliding member that has better wear resistance than conventional sliding members that have been subjected to surface treatment. , O ~ 3. It is characterized by having a silicon carbide particle iron plating layer in which silicon carbide particles of θμ are dispersed by j to 30% by volume, and a nitride layer is formed on the surface of the silicon carbide dispersed iron plating layer. Related to sliding members.

In order to manufacture the sliding member of the present invention, silicon carbide dispersion plating (hereinafter referred to as dispersion plating) is applied to the sliding surface of the base material in iron plating in which silicon carbide particles are suspended, and then nitriding is performed. The nitriding process includes gas nitriding, gas cutting nitriding,
Salt bath nitriding, ion 1. Any nitriding treatment such as H may be used. Base material 4 Common materials for sliding parts such as piston rings and 1. It is possible to use iron and steel materials that are used in iron-based materials such as cast iron, steel, iron-based sintered alloys, or iron-based heat-resistant alloys. In addition, in applying the dispersion amount plating, it is desirable to apply iron plating to the base material in advance in order to improve the adhesion of the dispersion amount plating layer.

Figure 1 is a micrograph (magnification, !00x) showing the structure of the cross section near the sliding surface of the sliding member of the present invention, (1) is the base material,
(a) is an iron plating layer, (a) is a dispersion plating layer, and (b) is a nitrided layer. Of these, (a) is a high hardness surface layer, so the wear resistance is significantly improved. be.

Dispersion amount Silicon carbide particles in the plating layer have an average particle size of O9j~3
．． A grain size of 0μ is preferred. If this is finer than O1jμ, the effect of improving wear resistance will be insufficient;
．． If it exceeds 0μ, the plating layer becomes brittle and localized chipping is likely to occur during sliding.

The amount thereof is preferably 5 to 30% by volume.

If it is less than 5%, the effect of improving wear resistance will be insufficient, and if it exceeds 30%, the wear of the mating material will increase. In addition, in Figure 1, it is desirable that the thickness of the iron plating layer 01 and the dispersion plating layer ■ be at least jμ from the viewpoint of the mechanical strength of the plating layer, and the thickness of the nitride layer From the point of view, including the hardened layer (a), 2! It is desirable that it is p- or more.

Next, an example will be described.

77mmX/, 2mmXJ, 2mm steel first pressure ring and 77mrnXO, A/rnmx2-3am steel combination oil type ring. An iron plating layer was formed. Next, a paste plating solution consisting of ferrous sulfate/≠Or/l, boric acid 30g/I, urea/IOg/It, and glycerin/j()ml/l was added with an average particle size of //lL (maximum particle size of 3μ).
10 g/j of silicon carbide particles were added and the bath was stirred in a tank to give an electric density of 1 is A/m",re
rmst-t, o″O on top of the above iron plating layer with thickness/2
A plating layer with a dispersion amount of 07' was formed. The amount of silicon carbide particles was 2j% by volume. Next, these were subjected to the usual salt bath nitriding treatment, and the surface of the dispersion plated layer was coated with a thickness of 20 μm.
A nitrided layer was formed.

These piston rings were assembled into a cylinder bore diameter 7711 high cycle, in-line, ≠ cylinder water-cooled engine, and jjoorpm was run using high lead gasoline as fuel.

A pliers test was conducted for 100 hours at full load, and the amount of wear on the outer circumferential sliding surface of the piston ring and the inner curved surface of the cylinder liner was measured. The material of the cylinder liner is cast iron 102j. For comparison, hard chrome plating, molybdenum spraying,
A similar test was conducted on a specimen whose outer sliding surface was coated with silicon carbide dispersed cobalt plating. The thickness of the silicon carbide dispersed cobalt plating layer is /307', and the particle size and the amount of dispersion of the silicon carbide particles are comparable to those of the dispersion amount plating layer of the present invention.

Pliers test (1) Use the above pressure ring as the first pressure ring, use a cast iron ring of 77mmX/, jmmXj, Jmm for the first pressure ring, and 77mmX0t/I! for the oil type ring. lll
lX231! Table 1 shows the results of a pliers test conducted under the above conditions using a combination ring having a chrome-plated rail of Im.

No./Table Pliers Test ■ Use the oil seeding ring described above, the first pressure ring is a chrome-plated ring, and the second pressure ring is a cast iron ring (all dimensions are as per the bench test standard above). Table 2 shows the results of a bench test conducted under the above conditions using the same method as in ).

Table 2 From the above bench test results, piston rings with a silicon carbide dispersed cobalt plating layer on the sliding surface have much better wear resistance than the comparative materials, and the material of the present invention has better wear resistance than this. It can be seen that the performance has been further improved.

As explained above, the sliding member of the present invention is suitable for piston rings of engines that use high lead gasoline as fuel, and has a wide range of applications as other sliding members that move at high speed, and has no industrial value. big.

[Brief explanation of drawings]

Figure 1 shows the structure around the sliding surface of the sliding member of the present invention.
This is a photo of a machine gun. (1): Base material, (J): Silicon carbide dispersed iron plating layer, (B): Nitride layer, (A): Hardened layer in the nitride layer. Applicant Riken Co., Ltd.

Claims (1)

[Claims] At least the sliding surface of the steel base material has an average grain size of O1j to 3.
A slide characterized by having a silicon carbide-dispersed iron plating layer in which silicon carbide particles of 0μ are dispersed in a volume ratio of j to 30%, and a nitride layer is formed on the surface of the silicon carbide-dispersed iron plating layer. moving parts.