JPH0285570A - Piston ring - Google Patents

Abstract

PURPOSE:To improve the adhesion and sliding characteristic by forming a nitrified layer on the surface of a piston ring made of chrome steel, forming a composite dispersion nickel strike plated layer on the outer periphery sliding face, and forming a composite dispersion nickel plated layer on it. CONSTITUTION:A nitrified layer 6 is formed on the surface of a piston ring 1 made of steel containing chrome 4.5-21wt.%. A composite dispersion nickel strike plated layer 7 with the thickness of 2-20mum and dispersed with hard grins 5-30vol.% made of metal nitride, carbide, or oxide with the grain size of 0.5-5mum in a nickel base is formed on an outer periphery sliding face 2, and a composite dispersion nickel plated layer 8 dispersed with hard grains 5-30vol.% made of metal nitride, carbide or oxide with the grain size of 0.5-5mum in a nickel alloy base containing tungsten 10-50wt.% is formed on it. A sliding film with excellent seizure resistance and abrasion resistance is obtained, this film has good adhesion, the side face abrasion is prevented, and the durability life can be improved.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a piston ring with excellent wear resistance having a composite dispersed plating layer, and more specifically relates to a piston ring with excellent wear resistance having a composite dispersion plating layer, and more particularly, to This invention relates to a piston ring that has improved hardness and sliding characteristics, and also has improved side wear resistance.

(Prior Art) In recent years, as the performance of internal combustion engines has improved, increasingly severe conditions have been imposed on each functional component, and there has been a strong demand for extending the life of internal combustion engines. Piston rings are also exposed to harsh environments such as high rotation, high temperature, and high surface pressure more than ever before, and there is a need for improved durability.As a means to improve the durability of piston rings, hard chrome plating is applied to the sliding surfaces. A wear-resistant surface treatment such as thermal spraying or nitriding is applied. Among these surface treatments, nitriding treatment is particularly
Since it exhibits excellent wear resistance, it has attracted attention as a surface treatment for piston rings used under severe operating conditions, and has recently been increasingly used.

However, while the nitrided layer conventionally used in piston rings has excellent wear resistance, its seizure resistance is not necessarily sufficient compared to hard chrome plating layers or thermal sprayed layers, and it is difficult to use under harsh operating conditions. Abnormal wear occurs when using the product. In order to improve the seizure resistance and durability of the nitrided layer, composite dispersion plating in which hard particles are dispersed in a nickel-tungsten base, which has excellent wear resistance and seizure resistance, has recently been used.

(Problem to be Solved by the Invention) However, when this composite dispersion plating film containing tungsten is applied to chrome steel, the adhesion and sliding properties are not sufficient when used under harsh operating conditions. There are problems such as peeling from the interface with the metal and abnormal wear, and improvements have been desired.

(Means for Solving the Problems) The present invention has been made by focusing on the problems of the above-mentioned composite dispersion plating containing tungsten.

The purpose of this invention is to provide a piston ring that has good adhesion and sliding characteristics on the outer circumferential sliding surface even under severe usage conditions, and has improved wear resistance on the side surface.

As a first invention, a nitride layer 6 is formed on the surface of a steel piston ring 1 containing 4.5 to 21% by weight of chromium,
2 to 20 in which 5 to 30 volume % of hard particles of metal nitride, carbide, or oxide with a particle size of 0.5 to 5 μm are dispersed in a nickel matrix on the outer peripheral sliding surface 2 of the piston ring.
It has a composite dispersed nickel strike plating layer 7 with a thickness of μm, and the strike plating scraps 7 are further covered with grains of 0.5 to 5 μm in a base made of a nickel-based alloy containing 10 to 50% by weight of tungsten. This piston ring has a composite dispersed nickel plating layer 8 in which hard particles of metal nitride, carbide, or oxide are dispersed.

As a second invention, a nitride layer 6 is formed on the surface of a steel piston ring 1 containing 4.5 to 21% by weight of chromium,
On the outer peripheral sliding surface 2 of the piston ring, 5 to 30 volume % of hard particles of metal nitride, metal carbide, or metal oxide with a particle size of 0.2 to 10 μm are dispersed in a nickel base. It has a composite dispersed nickel strike plating layer 7 with a thickness of 2 to 20 μm, and furthermore, on the strike plating layer 7, a nickel alloy base containing 10 to 50% by weight of tungsten has a particle size of 0.5 to 5 μm. A piston ring having a composite dispersed nickel plating layer 8 in which hard particles of pupil metal nitride, carbide, or oxide and solid lubricant particles with a particle size of 0.5 to 5 μm are dispersed in a total of 5 to 30% by volume. It is.

The base material of the piston ring of the present invention is chrome steel.

If the chromium content is less than 4.5% by weight, the nitrided layer will not be formed well, and if it exceeds 21% by weight, the workability will deteriorate, so the chromium content was set in the range of 4.5 to 21% by weight.

In the first invention, as shown in the cross-sectional schematic diagram of the piston ring in FIG.
By forming this, the wear resistance of the piston ring side surface 3 is particularly improved.

When plating the nitrided layer 6, a diffusion layer of nitrided H6 in the shell weakens the bond with the plating film and reduces adhesion.

Therefore, a simple nickel plating strike is used as a method to strengthen the adhesion with the composite dispersion plating, but a simple nickel plating layer has poor seizure resistance and wear resistance, and although the adhesion is sufficient, 8 In the present invention, which was insufficient as a sliding surface, a nickel strike plating layer 7 containing no tungsten is formed. This nickel strike plating layer 7 has a grain size of 0.2 to 10 μm, preferably 0.5 μm in order to increase the seizure resistance of the strike plating layer 7.
A dispersed layer of hard particles having a particle size of ~5μ is formed.

When a nickel-tungsten composite dispersion plated layer is subjected to heat curing treatment to increase its seizure resistance and wear resistance, Ni and W are generated, which reduces the adhesion to the base material. Therefore, the present invention is characterized by intervening as an intermediate layer a film that does not generate Ni4W even when subjected to heat curing treatment, that is, a hard particle dispersed plating layer 7 that does not contain tungsten. If the thickness of this composite dispersion strike plating layer 7 is too thin, sufficient adhesion effect cannot be obtained.6 In the present invention, the thickness of the nickel composite dispersion strike plating scrap 7 is 2 μm.
It is necessary to make it more than m. On the other hand, increasing the thickness of nickel composite dispersion strike plating Ji#7
If the nickel-tungsten composite dispersion plating layer 8 disappears due to wear and the strike plating layer 7 acts as a sliding surface, it will be inferior to the nickel-tungsten composite dispersion plating layer 8, so the outer periphery will wear more quickly, and the gap between the ring abutment 4 will increase. There is a problem in that as the increase progresses, the airtightness of the piston ring deteriorates. Therefore, in the present invention, the thickness of the nickel composite dispersed strike plating layer 7 is set to be 20 μl or less, preferably 10 μl or less.

The hard particles used here include metal nitrides such as TiN, Si3N, Cr, N, metal carbides such as Tic, SiC, Cr, C, and metal oxides such as At.
,O,,Tic2. Cr, 03, etc.

The dispersed amount and particle size of the hard particles are related to the thickness of the strike plating layer 7 to be formed, but if the dispersed amount is less than 5% by volume and the particle size is less than 0.2 μI, the effect on seizure resistance and wear resistance is insufficient. The dispersion amount is 30% by volume.If one particle exceeds 5μ, the attached layer becomes brittle and the wear of the sliding mating material increases. The range was 0.5 to 5 μm.

A nickel-tungsten composite dispersed plating layer 8 is further formed on the strike plating layer 7.

Tungsten has an effective effect on increasing the hardness of the plating base and improving wear resistance, but if it is less than 10% by weight, the effect is small, and if it is more than 50% by weight, it will make the plating base brittle. The range was 10 to 50% by weight.

The type, dispersed amount, and particle size of the hard particles are the same as those in the composite dispersed strike plating layer 7 described above.

In the second invention, when forming the nickel-tungsten composite dispersion plating layer 8 on the nickel-base composite dispersion strike plating layer 7 after forming the nitride layer 6, a solid lubricant is added in addition to the hard particles as a dispersant. This is a major feature. The rest is the same as the first invention.

Examples of solid lubricants include molybdenum disulfide, tungsten disulfide, and boron nitride.

As with hard particles, if the particle size is less than 0.5 μm, the effect of seizure resistance and wear resistance will be small, and if it exceeds 5 μI, the plating layer will become brittle and the wear of the sliding mating material will increase. The particle size range was 0.5 to 5μ layer.

If the amount of dispersion is less than 5% by volume including the hard particles, there will be little effect on seizure resistance and wear resistance, and if it exceeds 30% by volume, the plating layer will become brittle and the wear of the sliding counterpart will increase, so 1 dispersion is required. The amount ranged from 5 to 30% by volume.

Example (1) Seizure resistance test Alloy steel 5US440B (C: 0.75-0.95%,
Si: 1.0% or less, Mn: 1.0% or less, P: 0.0
4% or less, Ni: 0.60% or less, Cr: 16°0~
18.0%, Mo: 0.75% or less) is formed with a nitrided layer 6, on which 10% by volume of chromium carbide (Cr3C, ) having a particle size of 0°3 to 5 μm is dispersed in the nickel matrix. A strike plating layer 7 with a thickness of 5 μm is formed on the strike plating layer 7, and 10% by volume of chromium carbide with a particle size of 0.3 to 5 μm is dispersed in a nickel base containing 40% by weight of tungsten. Sample (A) of the first invention product with a composite dispersion plating layer 8 formed thereon, and a nitrided layer 6 formed thereon with chromium carbide (CR, C2) having a particle size of 063 to 5 μm in a nickel base. A strike plating layer 7 having a thickness of 5 μm in which 10% by volume of tungsten is dispersed is formed, and further, on the strike plating layer 5, carbonized particles having a particle size of 0.3 to 5 μm are formed in a nickel matrix containing 40% by weight of tungsten. A combination of chromium and molybdenum disulfide with a particle size of 0.3 to 5 μm is 1
A sample (B) of the second invention product in which a composite dispersion layer 8 having 0 volume % dispersion was formed was prepared, heat treated at 570° C. for 1 hour, and a seizure resistance test was conducted.

For comparison, a sample with conventional hard chrome plating (
C) and a sample (D) in which a nitrided layer was formed were prepared and subjected to the seizure resistance test in the same manner.

The main part of the test apparatus is shown schematically in FIG. 4, and FIG. 5 is a sectional view taken along the line A--A in FIG. 4.

diameter 8 removably attached to the stator holder 11
01111a x thickness 10 ■ Disc 12 with polished finish
Lubricating oil is applied to the center of the (mate material) from the back side through the oil filling hole 13. The stator holder 11 has a rotor 14 facing the zero disc 12, which is applied with a predetermined pressure to the left and right in the figure by a hydraulic device (not shown), and is rotated at a predetermined speed by a drive device (not shown). It is designed to rotate. The test piece holder 15, which is removably attached to the rotor 14, has a 5 mm square x 1 height
Four test pieces 10 of 0av+ are mounted concentrically at equal intervals in a removable manner and slidably relative to the disc.

In such a device, a predetermined pressing force P is applied to the stator holder 11, and the disk 12 and the test piece 10 are pressed together with a predetermined surface pressure.
The rotor 14 is rotated while supplying oil to the sliding surface from the oil supply hole 13 at a predetermined supply speed. The pressure acting on the stator holder 11 is increased stepwise at regular intervals, and the rotation of the rotor 14 causes friction between the test piece 10 and the disk 12 to cause the stator holder 1 to
1 is applied to the load cell 17 via the spindle 16 shown in FIG. It is assumed that seizure has occurred when the torque T suddenly increases, and the contact surface pressure at this time is taken as the seizure occurrence surface pressure, and the quality of the seizure resistance is judged based on the magnitude thereof.

The test conditions are as follows.

Friction speed: 8III/SeC Compatible material Nijilina liner material cast iron (Fe12) Lubricating oil: Motor oil #30 Oil temperature 80℃ Supply amount 400cc/+i
n Contact surface pressure: After leveling out at 40 kg/cm2, the pressure was increased by 10 kg/am2 until seizure occurred, and the test results were maintained at each surface pressure for 3 minutes, as shown in Figure 2. As is clear from the figure, seizure occurred in the comparative chromium-plated product (C) and nitrided product (D) at a contact surface pressure of 118 kg/cm" and 112 kg/c+a2, but in the present invention (A), In (B), seizure occurred at contact pressures of 141 kg/cm" and 149 kg/cm", confirming that the seizure resistance was greatly improved.

(2) Adhesion test Steel material of the same quality as used for seizure resistance test (SO8440B
), a piston ring 1 with a nominal diameter x width x thickness of 81 x 1.5 x 3゜3 m is prepared, a nitride layer 6 is formed on its entire surface, and a nickel matrix is applied to the outer sliding surface 2 of the piston ring 1. 10% by volume of chromium carbide with a particle size of 0.3 to 5 μm
A dispersed strike plating layer 7 is formed with a thickness of 5 μm, and tungsten is further coated on top of the strike plating layer 7 with a thickness of 5 μm.
The particle size is 0.3~ in the nickel base containing 0% by weight.
Sample of the first invention product (A
), and on the outer sliding surface 2 of the nitrided layer 6, a strike plating layer 7 with a thickness of 5 μm in which chromium carbide with a grain size of 0.3 to 5 μm is dispersed in a nickel base at a thickness of 10% by volume is formed; Furthermore, 4 layers of tungsten are formed on the strike plating layer 7.
The particle size is 0.3~ in the nickel base containing 0% by weight.
Sample (B) of the second invention product forming a composite dispersed nickel plating layer 8 in which chromium carbide of 5 μm and solid lubricant particles with a particle size of 0.3 to 5 μm are dispersed in a total of 10% by volume, as a comparison product On the outer peripheral sliding surface, a composite dispersed nickel plating layer in which 10% by weight of silicon nitride with a particle size of 0.3 to 5 μm is dispersed in a nickel matrix containing 25% by weight of cobalt and 40% by weight of tungsten is applied. The formed sample (C) was prepared, heat-treated at 570° C. for 1 hour, and an adhesion test was conducted.

The test device is a main part diagrammatically shown in FIG.
b, fix the gripping tool 9a, rotate the gripping tool 9b around the opposite side 5 of the abutment of the piston ring 1 as shown by the broken line, twist the piston ring 1, and twist the piston ring 1 into a predetermined position. A twist test was conducted in which the presence or absence of peeling of the plating layer on the opposite side 5 of the piston ring 1 to the abutment was visually observed at each twist angle.

Samples (A), (B), (C) (7) 40pm to husband'r,
60 μm, 80 prrr, 100 μm, 12
A plating thickness of 0 μm+ and 140 Pm was formed. The test results are shown in Figure 3.

As is clear from Figure 3, in the comparative sample (C) in which a composite dispersed nickel plating layer containing tungsten was formed directly on the base material of the piston ring, the plating layer peeled off from the base material at a low angle. Samples (A) and (B) of the present invention, in which a strike plating layer was formed on the base and a composite dispersed nickel plating layer was formed thereon, showed good adhesion, and the adhesion was greatly improved. This was confirmed.

(3) Actual machine test nominal diameter x width x thickness 81 x 1.5 x 3.3m+
The composite dispersion plating of the present invention was applied to the first pressure culling of ++ steel '1!1 (SUS440B), and it was assembled into a 4-cylinder water-cooled supercharged gasoline engine with a bore diameter of 81 mm, and a 7300r engine.
, p.

A high-speed durability test was conducted for 100 hours at the same rotational speed, and the amount of wear on the piston ring sliding surface and the inner circumferential surface of the cast iron (Fe12) cylinder liner was investigated, as well as problems such as peeling and seizure of the coating.

A nitrided layer 6 is formed on the entire surface of the piston ring 1, and a thick strike plating layer 7 is formed on the sliding surface 2, in which 10% by volume of chromium carbide with a grain size of 0.3 to 5 μm is dispersed in a nickel matrix. 5 μm of tungsten is formed, and 4 μm of tungsten is formed on top of that.
The particle size is 0.3~ in the nickel base containing 0% by weight.
Sample of the first invention product (A
), a nitride layer 6 is formed, and a strike plating layer 3 with a thickness of 5 μm is formed on the sliding surface thereof by dispersing 10% by volume of chromium carbide with a grain size of 0.3 to 5 μm in a nickel base, Furthermore, on top of that, chromium carbide with a particle size of 0.3 to 5 μm and a particle size of 0 in a nickel base containing 40% by weight of tungsten.
．． A total of 10% by volume of molybdenum disulfide with a diameter of 3 to 5 μm
Sample (B) of the second invention product forming the dispersed composite dispersed nickel plating layer 8, nickel containing 25% by weight of cobalt and 40% by weight of tungsten on the sliding surface as a comparison material A sample (C) formed with a composite dispersed nickel plating layer in which 10% by volume of chromium carbide with a particle size of 0.3 to 5 μm was dispersed in the matrix, and a sample (D) formed with hard chromium plating were prepared. Sample (A).

(B) and (C) were heat-treated at 570°C for 1 hour.

An adhesion test was conducted with each sample having a plating thickness of 100 μm. The test results are shown in Table 1.

As is clear from Table 1, the product without a strike plating layer on the base (C) had a small amount of wear, but peeling occurred, and the hard chrome plated product (D) did not have any peeling, but had significant wear. However, the piston ring of the present invention had good results with less wear on the cylinder liner and no peeling or seizure of the film.

Effects The present invention solves the problems of composite dispersion plating containing tungsten, has a sliding film with excellent seizure resistance and wear resistance even under severe usage conditions, and has good adhesion. The practical effects of obtaining a piston ring that prevents side wear and improves durability are significant.

[Brief explanation of the drawing]

Fig. 1 Schematic cross-sectional view of a piston ring showing an embodiment of the present invention Fig. 2 Fig. 3 showing the seizure resistance test results Fig. 4 showing the adhesion test results Fig. 5 A partially exploded view showing the parts Fig. 6 A cross-sectional view taken along the line A-A in Fig. 4 Schematic diagram showing the test device for adhesion test: Piston ring 2: Outer circumferential sliding surface 3: Side surface
4: Abutment 6: Nitride layer 7: Strike plating layer not containing tungsten 8: Dispersion plating layer 9a, 9b containing tungsten:
Gripping tool 1o: Test piece 11: Stator holder 12: Disk (mate material) 14: Rotor 15: Test piece holder 17: Load cell
18: Dynamic strain meter

Claims (1)

[Scope of Claims] 1. A nitrided layer is formed on the surface of a steel piston ring containing 4.5 to 21% by weight of chromium, and a nitride layer is formed on the outer peripheral sliding surface of the piston ring with a nickel matrix having a grain size of 0. .5~5μm
5 hard particles that are nitrides, carbides, or oxides of metals.
A base made of a nickel-based alloy having a composite dispersed nickel strike plating layer with a thickness of 2 to 20 μm in which ~30% by volume of tungsten is dispersed, and further containing 10 to 50% by weight of tungsten on the strike plating layer. Particle size 0.5-5μm
5 hard particles that are nitrides, carbides, or oxides of metals.
A piston ring characterized by having a composite dispersed nickel plating layer dispersed in ~30% by volume. 2. A nitride layer is formed on the surface of a steel piston ring containing 4.5 to 21% by weight of chromium, and a metal grain size of 0.5 to 5 μm in a nickel base is formed on the outer sliding surface of the piston ring. 5 to 5 hard particles of nitride, carbide or oxide
It has a composite dispersed nickel strike plating layer with a thickness of 2 to 20 μm in which 30% by volume of tungsten is dispersed, and furthermore, on the strike plating layer, a nickel alloy base containing 10 to 50% by weight of tungsten has a grain size of 0. Hard particles that are metal nitrides, carbides, or oxides of 5-5 μm and particle sizes of 0.5-5 μm
A piston ring characterized by having a composite dispersed nickel plating layer in which solid lubricant particles of 5 μm are dispersed in a total of 5 to 30% by volume.