JPS59162346A - Pressure ring - Google Patents

Abstract

PURPOSE:To improve the thermal fatigue resistance and the top-and-bottom side abrasion resistance of a piston ring by providing a surface treated layer on the sliding surface of stainless steel in martensite group having a specific proportion of C, Si, Mn, Cr, Mo, and Fe. CONSTITUTION:A piston ring 3 is made of stainless steel in martensite group with a metallic constitution consisting of 0.95 to 1.20% C, 0.20 to 1.00% Si, 0.20 to 1.00% Mn, 16 to 18% Cr, 0.30 to 0.75% Mo, and Fe and impurities for the remainder, by wt%, and is heat treated. In this heat treatment, the stainless steel is heated at 1,000 to 1,100 deg.C before it is quenched, and then it is tempered at 580 to 680 deg.C, being provided with a constitution in which 8 to 20% carbide by area% is precipitated. On the sliding surface of the ring is provided a hard surface treated layer 8 of a hard chrome plating etc. having good abrasion resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a piston ring, and particularly to a pressure ring suitable for application to internal combustion engines.

In recent years, internal combustion engines have been required to have increasingly higher performance, with higher output and faster speeds.In addition, they must also have measures against exhaust gases, and there is a need for countermeasures to the problem of increased fuel consumption due to decreased horsepower of internal combustion engines. Sexuality is increasing. Regarding these problems, the pressure ring that maintains the airtightness of the combustion chamber of the internal combustion engine has a great influence on the performance of the internal combustion engine, and countermeasures are especially needed.

Traditionally, pressure rings for internal combustion engines have been made of cast iron, carbon steel, silicon chrome steel, or oil-tempered wire, but cast iron rings are difficult to manufacture because they are thin in the axial direction. Since chrome steel rings have low strength at high temperatures, they are relatively heavy with a large cross section, and have a large inertia, making them prone to flutter.Also, cast iron rings and Silichrome 1mm steel rings lack heat resistance and wear resistance on the upper and lower surfaces, and the rings cannot be installed close to the piston rings, which is advantageous in preventing waste removal, and the spacing between the rings cannot be made small. Therefore, there was a problem that the weight of the piston was heavy and it was difficult to achieve high output and high speed.Therefore, recently, CD, which has excellent high temperature strength, has a high e-
Good results have been obtained using 13Cγ4 rutinsite filter stainless steel in pressure rings.

The present invention has been made in view of these problems, and is a ring that has higher strength, heat resistance, and upper and lower surface wear resistance than these high C-13Cγ martensitic stainless steel rings. It is an object of the present invention to provide a pressure ring that can achieve high output and high speed parts of an internal combustion engine while maintaining good airtightness without causing any flaring or sagging phenomenon.

That is, the present invention has an alloy composition with a weight ratio of CD, 95.
1.20', Si0.20~1.00, 1Vl
tt, 0.20 to 1.00', -Cr16 to 18, MOo, 50 to 0.75 Martensitic stainless steel consisting of residual part F6 and impurities (°C) is used in a heat-treated state, and Cτ carbide The area of the piston ring is at least 1).

There is Cγ plating on the sliding surface that slides on the underside wall.

This is a pressure 1 ring with good heat resistance and wear resistance on the upper and lower surfaces.

The pressure ring according to the present invention will be described below.

A cross-sectional view of an internal combustion engine incorporating a piston ring is shown in FIG. 1, and a perspective view of a pressure ring is shown in FIG.

1 is the cylinder, 2 is the piston, and 3 and 4 are the pressure pots.

5 is the oil ring, 6 is the abutment gap, and 7 is the outer peripheral surface. Pressure rings need to have excellent airtightness, wear resistance, seizure resistance, and breakage resistance, but this is especially important for the high output and high speed of internal combustion engines.

Further measures are required.

In the present invention, without causing the fluffing phenomenon,
In order to increase the rotational speed of internal combustion engines, the pressure ring is made of a stronger material and narrower than conventional cast iron rings and silicone rubber rings. In order to achieve this, the pressure ring is placed close to the top of the piston, as described above. With the pressure ring, it is possible to maintain good performance of the internal combustion engine even with the reduction in size and high power associated.

This was done with particular attention to heat resistance and abrasion resistance on the upper and lower surfaces. A partial cross-sectional view of the pressure ring is shown in Part 6.
As shown in the figure, the pressure ring 3 or 4 of the present invention is made of stainless steel with an alloy composition having the components described below. The outer peripheral surface 7 has a surface treatment layer 8 such as Cγ plating or nitriding.

The reasons for limiting the composition of the pressure ring of the present invention will be described below. C imparts high strength and wear resistance, but for that purpose, a small amount (at least 0.95') is required.However, if the C content is high, bending property is poor. The upper limit was set at 1.201 because this would make it difficult to perform S/G molding.

Si has the effect of increasing heat resistance and wear resistance on the upper and lower surfaces, so a small amount (0.2% or more of both is required. However, if it is excessive, it will impair plating properties and workability, so the upper limit is 1.0. .

Since MrL is contained as a deoxidizing agent and at the same time has the function of changing the form of sulfide, it is necessary to contain 0.2% or more in order to obtain a form of sulfide suitable for a pressure ring.

However, as with Si, excess content impairs plating properties, so the upper limit is set at 1.0%.

C? `` is effective in combining with C to form carbides and increasing heat resistance, corrosion resistance, seizure resistance, and upper and lower surface wear resistance, but if too much, heat treatment stiffness decreases. , and also deteriorates moldability, so it is limited to 16 to 181 in relation to the C content.

MO improves the hardenability of steel, and like Cr, it combines with C to form carbides, which is very effective in increasing wear resistance and strength of the material, and also works to increase heat resistance and corrosion resistance. Since it is an expensive element, it is necessary to take into consideration the required characteristics as a pressure ring.
．． 60-0.75".

In the present invention, the above-mentioned predetermined amounts of C, Cr, and Mo are contained, heated to 1000 to 1100, then rapidly quenched, and tempered to 580 at 680''C to precipitate carbides with an area of 8 to 20. The parts of the pressure ring that require good structure, wear resistance, and seizure resistance, that is, the sliding surface of the pressure ring that slides against the cylinder wall, are at least hard and have a surface treatment with good seizure resistance. A layer 8 is provided.As the surface treatment, various surface treatments such as hard Cr plating, porous Cr plating, composite plating, CrM spraying, and M6 thermal spraying can be appropriately applied.In particular, the surface treatment layer may be hardened. C
When the plating layer is closed, the sliding surface of the pressure ring that slides on the cylinder wall has a high roughness of lVa 50 or more.
In addition, the number of friction needles is small and it has excellent wear resistance, seizure resistance, and corrosion resistance, so it exhibits good airtightness as a sliding surface of the pressure ring, and as mentioned above, the pressure ring itself has excellent heat resistance. The pressure ring of the present invention is superior to other pressure rings because of its excellent airtightness due to the self-tension of the pressure carifugu 10, which is brought about by the high temperature tensile strength and wear resistance of the upper and lower surfaces. It is something that performs a function.

Also, among the outer circumferential surfaces of the pressure ring, at least the sliding surface of the pressure ring that slides on the cylinder wall must have two surface treatments/layers. Of course, a treatment layer may be provided.

Next, the effects of the present invention will be explained using examples.・Table 1 shows the chemical compositions of the ring of the present invention and the conventional ring.

Table 2 shows the comparison results of the characteristics of rings of the present invention and conventional rings after heat treatment.

Table 2: Heat resistance and fatigue resistance of a 5φ x 150” round bar at room temperature with a radius of curvature of 2
1 with the load required to bend it to 5 and a state of 25R bending.
0 Xl This shows the reduction rate of the load required to return to the natural state and bend to the same radius of curvature after heating, and the smaller the reduction rate, the better the heat resistance.

Abrasion resistance was measured using the Okoshi type rapid abrasion tester (Mating material 2 SC1!
121 annealed material, friction distance = 400'', final load: 6.8 kg, friction speed: 1.st+-/,,,
) shows the specific wear amount.

Table 2 shows that the ring of the present invention is superior to conventional rings in terms of heat resistance, high temperature tensile strength, and upper and lower surface abrasion resistance.Using the ring of the present invention can reduce ring weight and piston weight. Energy loss due to inertia can be reduced, and it has excellent airtightness and durability, making it possible to increase the output and speed of internal combustion engines.

Next, the ring of the present invention and the conventional ring were assembled into an actual machine as a brown 1 compression ring, and a comparative test was conducted on the amount of wear on the upper and lower surfaces of the rings. As the ring of the present invention, a ring having the chemical composition shown by the symbol (A) used in the &'1 characteristic comparison test was used, while the conventional ring was made of silicon chrome steel and high C-13Cr shown by the symbol (L). A stainless steel ring was used. The outer circumferential surface of each ring is plated with hard chrome.

(Test engine) Inner diameter X Row 8: 85φ x 781nr'L total displacement
: 1700c' Maximum output -98/s 7o or p, m (test conditions) Fuel: Leaded gasoline 6.1~3,2'9pt
: Rotation a: Fwll/60oor! P+" Operating time: 200 hours As a result, the average wear amount of the conventional silicon chrome steel ring was 33μ, whereas the high c-1scγ stainless steel indicated by the symbol (D) was 5μ on average. It was confirmed that the average wear amount was 2μ, demonstrating extremely excellent wear resistance.

As described above, the pressure ring of the present invention has excellent heat resistance and wear resistance on the upper and lower surfaces, and has excellent airtightness, seizure resistance, breakage resistance, etc. as a pressure ring, and at the same time, The amount of pressure ring M and the weight of the piston can be reduced, reducing energy loss due to inertia (at the same time, the contact area with the cylinder wall can be reduced by 1, reducing friction loss, making it possible to achieve high output of the internal combustion engine and at the same time be effective in reducing exhaust gas) That is.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view of an internal combustion engine incorporating a piston ring, FIG. 2 is a perspective view of the pressure ring, and FIG. 2 is a partial sectional view of the pressure ring of the present invention. 1 Niji cylinder - 12: Piston, 6.4: Pressure ring, 5 Niji oil ring, 6: Abutment gap, 7: Outer peripheral surface, 7 8: Surface treatment layer. Procedural amendment (spontaneous) 1,!, Jt+ 5ν・”1113 TI Indication of the case of the Commissioner of the Japan Patent Office 1982 Permanent Application No. L 30465 Name of the invention Name of the person making the pressure ring amendment Material (5081 Representative of Hitachi Metals Co., Ltd. Norio Kono Hitachi Kin I: Muku style company sex appeal (8001) Detailed description of the invention in the specification subject to amendment by patent attorney Tachibana Takaishi

Claims (1)

[Claims] 11 CD, 95-1.20 bits, Sio, 2o-1.
00min. MrLo, 20~i, Oo, Cr16~18',
It contains MOo, 3o to o, 75', and the remainder consists of Fe and impurities. A pressure ring that is made of martenusitic stainless steel and has a surface treatment layer on the sliding surface that slides on at least the cylinder wall of the piston ring, and has excellent heat resistance and wear resistance on the top and bottom surfaces.