JPH05230596A - Piston ring material - Google Patents

Abstract

PURPOSE:To provide a piston ring material excellent in seizing and wear resistances with a relatively low-cost low-alloy steel. CONSTITUTION:This piston ring material has a compsn. consisting of, by weight, 0.50-1.40% C, <=2.0% Si, <=2.0% Mn, 0.5-<5.0% Cr, 0.5-5.0% Cu and the balance Fe with inevitable impurities or further contg. <=1.0% Mo and/or <=1.0% W, <=0.5% V and/or <=0.5% Nb, <=2.0% Ni, <=1.0% Co and <=0.15%, in total, of 0.04-0.10% S and/or <=0.1% Se.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piston ring material used in an internal combustion engine for automobiles, ships, general purpose and the like.

[0002]

2. Description of the Related Art In order to meet the demand for higher speed and higher output of internal combustion engines, especially automobile engines, it is necessary to reduce the weight of piston rings and improve mechanical strength. A part of the oil ring is made steel. However, cast iron such as FC25 is still applied to the second ring, which has a relatively small load.

[0003]

The top ring and the oil ring have already been partially made steel,
In order to achieve higher performance, steeling of the second ring is desired. The second ring needs to have seizure resistance and wear resistance due to sliding with the cylinder, but the operating environment is relatively lighter than that of the top ring. The piston ring material of the present invention was originally developed for the second ring based on a relatively low alloy steel, but it can also be applied to the top ring and oil ring by subjecting the combination within the specific composition and the surface treatment to the piston ring. It is applicable enough. The object of the present invention is a piston ring material which is based on relatively inexpensive low alloy steel and has excellent seizure resistance and wear resistance. This enables weight reduction.

[0004]

SUMMARY OF THE INVENTION The present invention provides C in weight percent.
0.50 to 1.40%, Si 2.0% or less, Mn 2.0% or less, Cr 0.5%
A piston ring material whose basic system is a composition consisting of at least 5.0% and less than Cu, 0.5 to 5.0% Cu, the balance Fe and unavoidable impurities.
Type or 2 types, V 0.5% or less and Nb 0.5% or less 1 type or 2 types, Ni 2.0% or less, Co 10.0% or less and S 0.04 to
One or two kinds of 0.10% and Se 0.1% or less can be appropriately added in a total amount of 0.15% or less.

[0005]

The reason for limiting the components in the present invention will be described below. C is an M ₃ C type carbide, and further Cr, Mo, W,
It is an important element for forming special carbides with V and Nb, and partly forming a solid solution in the matrix to form a matrix with a high hardness martensite structure and improving seizure resistance and wear resistance. If the amount is small, the above effect is not obtained, and if the amount is too large, the productivity of the flat wire, which is the material of the piston ring, and the workability of the ring become difficult, so C is limited to 0.50 to 1.40%. Si is added as a deoxidizer, but if it is too much, it deteriorates the cold workability, so it is made 2.0% or less.

Mn, like Si, is added as a deoxidizing agent. However, if the amount is too large, the workability in hot or cold is deteriorated, so Mn is limited to 2.0% or less in consideration of the piston ring which requires a high working rate. Cr mainly forms an M ₃ C type carbide together with C, and has an effect of increasing strength and toughness. In the case of the material of the present invention, the Cr-based carbide is Fe-Cu.
Combined with the lubrication effect of the solid solution, it exhibits excellent effects of improving seizure resistance and wear resistance. Further, it has an effect on hardenability and is necessary for obtaining sufficient heat treatment hardness. Further, it is an important element because it forms a hard nitride when it is nitrided. If the amount is small, the above effect is not obtained. If the amount is too large, a huge Cr-based carbide is formed and cold workability is deteriorated.

Mo and W form a special carbide together with C and have the effect of further improving the wear resistance of the material of the present invention, and are added alone or in combination. If too much, huge carbides are formed, the production of flat wire becomes difficult, and the cost becomes high. Therefore, Mo and W are each set to 1.0% or less.
Similar to Mo and W, V and Nb form a special carbide together with C and have the effect of further improving wear resistance, and are added alone or in combination. However, since it forms hard carbides, if it is excessively added, the cylinder, which is the mating material, is likely to wear. Therefore, V and Nb are respectively
0.5% or less. Ni has the effect of improving the toughness of the material of the present invention. However, excessive addition hinders a decrease in hardness during annealing, so Ni is made 2.0% or less. Co is
It has the effect of forming a solid solution in the matrix, forming a dense coating on the surface, and improving the seizure resistance with the cylinder that is the mating material.
If it is too much, the cost will increase, so it should be 10.0% or less.

Cu precipitates as a Fe-Cu solid solution during heat treatment, and is an important element for improving seizure resistance and wear resistance due to the lubricating action of the precipitate. If the amount is small, the effect of the above addition cannot be obtained, and if the amount is too large, the hot workability is deteriorated, so the content of Cu is limited to 0.5 to 5.0%. S, Se
Is a non-metallic inclusion, and has the effect of improving the seizure resistance due to its lubricating effect, so it is added alone or in combination. Further, the non-metallic inclusion has a function of holding the engine oil, and in addition to its own lubricating function, the lubricating effect of the oil can be further increased. The addition of Se in combination can control the form of the non-metallic inclusions in a spindle shape and the amount of engine oil can be accumulated more than in the case of adding S alone. If it is too large, the mechanical properties will be deteriorated, so S is 0.04 to 0.10% and Se is 0.10% or less.

The piston ring material having the above composition is a relatively inexpensive low alloy steel, and is not only optimal as a second ring but also made of chromium on at least the sliding surface of the piston ring using this, which slides on the cylinder. By carrying out a surface treatment such as plating or nitriding treatment, it becomes possible to enhance seizure resistance and abrasion resistance, and it can also be used as a top ring.

[0010]

EXAMPLES The effectiveness of the material of the present invention will be shown below based on examples. Table 1 shows the chemical composition (wt%) of the material of the present invention and the comparative material.
Indicates. Inventive material A is a material in which Cu is added to Si-Cr steel, comparative material R is Si-Cr steel, and comparative materials S, T and U are
Among the compositions of the materials B, C and G of the present invention, Cu is not added. Inventive materials A to Q and comparative materials R to U
Was forged after ingot casting, annealed at 800 ° C, quenched at 950 ° C, tempered at 400 to 550 ° C, adjusted to a hardness of HRC40 to 45, and used as the test sample shown below. ..

[0011]

[Table 1]

Table 2 shows the results of testing the seizure resistance and wear resistance of each sample. These tests were carried out using an ultra-high pressure abrasion tester, and the outline of the test procedure is shown in FIG.
And shown in FIG. Table 3 shows the conditions of the seizure test and abrasion test conducted using this tester.

[0013]

[Table 2]

[0014]

[Table 3]

Inventive material A, B, C, G containing Cu
It can be seen that in comparison with the comparative materials R, S, T, and U, which have no additives, the seizure-occurring surface pressure is higher, the amount of wear is smaller, and both seizure resistance and wear resistance are improved. Among the materials of the present invention containing Cu, those in which W, Mo, V, Nb are added to cause a large amount of special carbides to be deposited tend to have good wear resistance values. Inventive material E added, and Inventive material G further added Co, S, Se
Has significantly improved seizure resistance. Table 2 also shows the results of the seizure and abrasion tests when the nitriding treatment was performed. The condition of the nitriding treatment was a gas nitriding treatment at 540 ° C. for 20 hours, which was performed on the inventive materials A to Q and the comparative materials RU. It can be seen that seizure resistance and wear resistance are further improved by nitriding each material. Even when nitriding is performed, the lubricating effect of Cu is effective and its order does not change.

[0016]

INDUSTRIAL APPLICABILITY The present invention can be applied to a relatively inexpensive low alloy steel, Cu
By adding the, the seizure resistance and wear resistance due to sliding with the cylinder is greatly improved, and among the piston rings of internal combustion engines where cast iron etc. were conventionally used,
Especially suitable as a second ring that does not require much load. As a result, reduction in weight and improvement in mechanical strength can be achieved by making steel, and the demand for high speed and high output of the internal combustion engine is met. Further, by subjecting at least the sliding surface of the piston ring using these piston ring materials that slides to the cylinder, it can be used also as a top ring.

[Brief description of drawings]

FIG. 1 is a schematic view of a seizure and wear test procedure using an ultrahigh pressure wear tester.

FIG. 2 is a sectional view taken along the line AA of FIG.

[Explanation of symbols]

 1 Test piece (5mm square x 10mmL) 2 Disc (counter material ... FC25) 3 Stator holder 4 Rotor 5 Test piece holding jig 6 Lubricating oil inlet 7 Load cell 8 Dynamic strain gauge P Friction pressure

Claims (6)

[Claims] 1. C 0.50 to 1.40% by weight, Si 2.0% or less, Mn 2.0% or less, Cr 0.5% or more and less than 5.0%, Cu 0.5 to
Piston ring material characterized by being 5.0%, the balance being Fe and inevitable impurities. 2. C 0.50 to 1.40% by weight, Si 2.0% or less, Mn 2.0% or less, Cr 0.5% or more and less than 5.0%, Cu 0.5 to
5.0% and Mo 1.0% or less, W 1.0% or less 1 or 2
A piston ring material containing seeds and comprising the balance Fe and unavoidable impurities. 3. The piston ring material according to claim 1, wherein a part of Fe is replaced by one or two of V 0.5% or less and Nb 0.5% or less. 4. The piston ring material according to claim 1, wherein a part of Fe is replaced with Ni 2.0% or less. 5. The piston ring material according to claim 1, wherein a part of Fe is replaced by Co 10.0% or less. 6. A part of Fe is S 0.04 to 0.10%, Se 0.1%
The piston ring material according to any one of claims 1 to 5, wherein one or two of the following are substituted by a total of 0.15% or less.