JPH0119060B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an internal combustion engine, and more particularly to a side rail of a combination oil ring composed of a steel side rail and a spacer expander, and a cylinder in a sliding relationship relative to the side rail. The aim is to provide an optimal combination of liners.

In this oil cylinder, as shown in FIG. 1, two side rails 1, 1 are supported by a spacer expander 2 in the axial and radial directions, and the outer peripheral surface 11 of the side rails slides on the inner peripheral surface 31 of the cylinder liner. It is.

First of all, this oil ring usually has a side rail.
It is a thin ring with a width of 1.0 mm or less and has flexibility in its behavior in the radial direction, which improves its ability to follow the inner circumferential surface of the cylinder liner and provides an excellent sealing function. Therefore, steel wire rods have to be used to meet the basic requirement of thinning, and the mechanical properties of this steel material pose various problems when used in piston rings, and improvements have been desired. The biggest problem is that under high-temperature, high-load conditions such as in diesel engines, steel materials undergo a so-called heat-settling phenomenon and lose their self-tension, and the side rails are extremely worn, requiring anti-wear measures. It was hot.

That is, in the past, in order to address the above-mentioned problems with oil rings, particularly as a countermeasure against wear, the outer circumferential surface of the side rail (made of carbon steel) was coated with a surface coating such as hard chrome plating. Currently, if this hard chrome plating treatment is not performed and the side rails are used as carbon steel, scuffing will occur.

In other words, the outer circumferential surface of the side rail is the sliding surface with the inner circumferential surface of the cylinder, so the most wear resistance is required, but it is generally coated with chrome plating as mentioned above, but chrome plating is not the same as a chrome plated cylinder. When used in combination, wear occurs due to metal-to-metal contact of the same material, and not only is corrosion abrasion likely to progress in diesel engines and high-lead gasoline engines, but there are also problems such as chrome plating waste liquid pollution.

In view of the above points, the present invention provides a side rail with excellent wear resistance without any surface treatment on the outer peripheral surface of the side rail of the oil ring, and a hardened side rail that is an optimal combination with the side rail. It provides cylinder liners.

That is, as for the side rail of the oil ring in the present invention, the matrix structure of the base material is tempered martensite, and fine grained carbide having a hardness of HV1200 to 1500 with a size of 10μ or less is dispersed in an area ratio of 3 to 7%. , the overall hardness is HRC38-43, and the weight ratio is C0.85-0.95%, Si1.0% or less, Mn1.0% or less,
Cr17.0~19.0%, Mo1.0~1.3%, V0.07~0.12%,
The remainder is martensitic stainless steel containing unavoidable impurities, and as a cylinder liner, it has a weight ratio of T.
C.2.5~3.5%, Si1.5~2.5%, Mn0.5~1.0%, P0.2
~0.8%, S0.2% or less, B0.02~0.15%, Cu or
Ni0.15~1.0%, Mo0.1~1.0%, Cr or V0.1~1.0
%, the balance consists of iron and unavoidable impurities, and the matrix structure is made into a martensite matrix by quenching, and the matrix has high hardness carbide in the area ratio of 5 to 25%, and the hardness of the matrix and carbide is The difference is
It is made of alloyed cast iron with a rating of HV300 or higher, and is a combination of both.

The reason for limiting the components of the side rail of the oil ring of the present invention will be described below.

Since the surface structure of the side rail is uniformly dispersed with fine granular carbides of 10μ or less, it is possible to prevent cracks from occurring around the carbide, and the amount of carbide is in the range of 3 to 7% of the area ratio. Embrittlement can be prevented by setting the In addition, if the hardness of fine grained carbide is less than HV1200, the side rail outer peripheral surface wear will be excessive.
If it exceeds HV1500, the spacer expander will wear out significantly, so it is necessary to set it in the range of HV1200 to HV1500.

If the overall hardness of the side rail is less than HRC38, the mechanical properties of the steel material make it difficult to use it as a piston ring.
With HRC43 or higher, molding becomes difficult.
It is set to HRC38 to HRC43.

The amount of C is to control the amount of carbide, and if it is less than 0.85%, carbide is insufficient, and if it exceeds 0.95%, it is too much.

Si acts as a deoxidizing agent, but if it exceeds 1.0%,
Its action is too strong and tends to cause brittle tissue with adverse effects.

Regarding Mn, it has a deoxidizing and desulfurizing effect, but 1.0%
If it is too high, oxidation resistance and acid resistance will deteriorate.

In addition to acting as a carbide-forming element, Cr is used to improve heat resistance and corrosion resistance, and if it is less than 17.0%, the effect will not be sufficiently obtained.
If it exceeds 17.0%, it becomes brittle and cannot withstand use.
Set to 19.0%.

Mo and V act as resistance elements against the softening of the base metal, and also contribute to the formation of carbides. Mo is effective at 1.0% or more, V is 0.07% or more, and Mo over 1.3% is effective. V is selected within this range because if it exceeds 0.12%, no significant improvement in effect can be obtained depending on the amount added.

Next, let's talk about the cylinder liner.

Regarding the amount of C, if it is less than 2.5%, the graphite amount and graphite shape with excellent scuffing resistance will be inappropriate, and if it exceeds 3.5%, the graphite will become coarse and the strength required as a cylinder liner material will be insufficient.

When the amount of Si is less than 1.5%, the amount of graphite is insufficient and a problem of chilling occurs, and when it exceeds 2.5%, graphitization is promoted too much, resulting in coarsening of the graphite and a decrease in strength.

Regarding the amount of Mn, if it is less than 0.5%, the strength of the material
It is not possible to eliminate the negative effects of S, which causes material embrittlement due to impurities, and Mn strengthens pearlite.
It combines with S to become MnS and is included to prevent material embrittlement, but it is unnecessary if it exceeds 1.0%.

When the amount of P is less than 0.2%, the amount of steadite, which has excellent wear resistance, decreases, and when it exceeds 0.8%, the amount of steadite increases, leading to quench cracking during heat treatment.

If the S content exceeds 0.2%, it will lead to embrittlement of the material.

If the amount of B is less than 0.02%, the amount of special steadite that contributes to wear resistance will be small, and if it exceeds 0.15%, the amount of special steadite will be excessive and the material will become brittle.

Cu or Ni is contained mainly for the purpose of strengthening the matrix structure, but if it is less than 0.1%, it has no effect, and if it is contained in excess of 1.0%, the matrix structure changes, which is not desirable.

The amount of Mo is an effective element for improving hardenability and strengthening the matrix structure. If it is less than 0.1%, no significant effect can be obtained, and if it exceeds 1.0%, the matrix structure tends to become bainitic, resulting in poor machinability. It was set at 1.0% or less because the hardening of the parts that require it becomes high.

Cr or V is a carbide-forming element, and if it is less than 0.1%, it has no effect, and if it exceeds 1.0%, the carbide increases and the material becomes hard and brittle.

In the cylinder liner material of the present invention, an appropriate amount of carbide is precipitated in the structure to improve scuffing resistance, and the high hardness of carbide improves wear resistance, but if the area ratio is less than 5%, sufficient scuffing resistance and Wear resistance cannot be obtained and if it exceeds 25%, carbides will be excessive and machinability will be impaired. The matrix structure is formed by heat treatment such as induction hardening or flame hardening, which rapidly heats the material and hardens it to martensite without decomposing the carbide, but the hardness is generally HV400 or higher, and precipitates are formed. Steadite has the lowest hardness, about HV700, and if the difference in hardness between the base and carbide is less than HV300, the wear rate of each will be low, making it difficult to retain lubricating oil, and the wear resistance and Scattering effect cannot be obtained.

As described above, the present invention provides a side rail with excellent wear resistance without any surface treatment on the outer circumferential surface of the side rail of the oil ring, and also has a quenched side rail that is an optimal combination with the side rail. This is to obtain a cylinder liner that is made of aluminum.

In order to prove this, the results of a wear test are shown below.

ΓInvention (side rail material) ●Components (weight%) C: 0.82, Si: 0.42, Mn:
0.38, P: 0.0023, S: 0.008, Ni: 0.18, Cr:
17, 20, Mo: 1.12, V: 0.14, residual Fe ●Hardness HRC41 (cylinder liner material) ●Components (weight%) C: 3.32, Si: 2.19, Mn:
0.79, P: 0.31, S: 0.08, B: 0.025, Cu:
0.33, Mo: 0.21, Cr: 0.67, residual Fe ●Matrix structure: martensite, carbide (quenched and tempered) ・Hardness HRC40 Conventional example 1 (side rail material) ●Component (weight%) C: 081, Si: 0.30 , Mn:
0.43, P: 0.025, S: 0.013, residual Fe ●Hardness HV351 (cylinder liner material) ●Components (weight%) C: 3.32%, Si: 2.19, Mn:
0.79, P: 0.31, S: 0.08, Cu: 0.25, Mo:
0.21, residual Fe ●Base structure: pearlite, steadite ●Hardness HRB97 Conventional example 2 (side rail material) ●Components (weight%) C: 0.82, Si: 0.42, Mn:
0.38, P: 0.0023, S: 0.008, Ni: 0.18, Cr:
17.20, Mo: 1.12, V: 0.14, residual Fe ●Hardness HRC41 (cylinder liner material) ●Component (weight%) C: 3.32%, Si: 2.19, Mn:
0.79, P: 0.31, S0.08, Cu: 0.25, Mo: 0.21,
Residual Fe ●Base structure: pearlite, steadite ●Hardness HRB97 Conventional example 3 (side rail) ●Hard Cr plating is applied to carbon steel.

●Hardness HV900 (Cylinder liner material) ●Components (weight%) C: 3.32, Si: 2.19, Mn:
0.79, P: 0.31, S: 0.08, Cu: 0.25, Mo:
0.21, residual Fe ●Base structure: pearlite, steadite ●Hardness HRB97 In the above example, the fixed piece (12 mm x 18 mm x 5 mm)
is equivalent to the side rail material, and a disk-shaped sample (inner diameter
105 mm, outer diameter 139 mm, thickness 7 mm) is equivalent to cylinder liner material, and this fixed piece is pressed against the top surface of the disc-shaped sample so that it is in plane contact with the disc-shaped sample.While lubricating oil is constantly supplied to the pressed surface, the disc is The sample was rotated and the time until scuffing occurred was measured.

(Test conditions) ●Sliding speed: 0.15m/sec ●Surface pressure: 50Kg/cm ² ●Lubricating oil: SAE #30 ●Oil temperature: 60℃ The results are as shown in Figure 2, and the present invention is different from the conventional example. 1. It is clear that the scuffing resistance is superior to Conventional Example 2, and the hard chrome plating on the outer peripheral surface of the side rail, which is commonly used in the past and is said to have high wear resistance, as shown in Conventional Example 3. The scuffing resistance was almost equal to or better than that of the treated material.

As described above, the present invention provides a side rail with excellent wear resistance without any surface treatment on the outer circumferential surface of the side rail of the oil ring, and a hardened cylinder that is an optimal combination with the side rail. A liner can be obtained, and the effect is great.

[Brief explanation of drawings]

Figure 1: Cross-sectional view showing the combination of a combination oil ring and cylinder liner. FIG. 2: A graph of test results showing a comparison between the present invention and a conventional example.

Claims (1)

[Claims] 1. The side rail of a combination oil ring composed of a steel side rail and a spacer expander is used as a side rail as shown below, while the cylinder liner is used as a cylinder liner as shown below. internal combustion engine. Side rail of the combination oil ring: The matrix structure of the base material is tempered martensite, and fine grained carbides with a hardness of HV1200 to 1500 less than 10μ are dispersed in an area ratio of 3 to 7%, and the overall hardness is
HRC38~43 and weight ratio C0.85~0.95
%, Si1.0% or less, Mn1.0% or less, Cr17.0~19.0
The side rail is martensitic stainless steel containing unavoidable impurities, Mo1.0~1.3%, V0.07~0.12%. Cylinder liner: TC2.5~3.5 in weight ratio
%, Si1.5~2.5%, Mn0.5~1.0%, P0.2~0.8%,
S0.2% or less, B0.02~0.15%, Cu or Ni0.15~1.0
%, Mo0.1~1.0%, Cr or V0.1~1.0%, the balance consists of iron and unavoidable impurities, and the base structure is a martensite base with high hardness carbide in area ratio of 5~1.0%.
25%, and the hardness difference between the base and carbide is HV300
That's all for the cylinder liner.