JPS63195365A - Cylinder bore for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent the abrasion at the inner surface of a bore, by swelling and welding anticorrosive and antiabrasive alloys with different components near the top dead center of compression rings and near the top dead center of an oil ring respectively at the inner surface of the cylinder bore. CONSTITUTION:At the inner surface of a cylinder bore 2, the first anticorrosive and antiabrasive alloy 6 is swelled and welded near the top dead center of compression rings 3 and 4, while the second anticorrosive and antiabrasive alloy 7 is swelled and welded near the top dead center of an oil ring 5. In this case, the first swelled layer 6 is formed of an excellent anticorrosive alloy, while the second swelled layer 7 is formed of an excellent mechanically antiabrasive alloy. Therefore, the abrasion can be suppressed sufficiently both near the top dead center of the compression rings where the corrosive abrasion is severe and near the top dead center of the oil ring where the mechanical abrasion is severe.

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a cylinder bore used in an internal combustion engine such as an automobile diesel engine, and particularly relates to a cylinder bore that takes measures against wear on the bore surface near the top dead center of a bisto cylinder. .

Conventional technology The inner surface of the cylinder bore of an internal combustion engine such as a diesel engine,
In particular, the area near the top dead center of the piston ring is subjected to mechanical sliding friction by the piston ring and carbon suit, and at the same time is subjected to sulfuric acid dew point corrosion caused by SO2 contained in the combustion gas, and these act synergistically to cause local damage. It is known that wear progresses prematurely. If local wear of the cylinder bore progresses in the vicinity of the top dead center of the piston ring, a local recess will be formed in that area, resulting in a reduction in output due to poor compression, so it is necessary to suppress such wear as much as possible. be.

By the way, as conventional measures against wear in cylinder bores, for example, Japanese Patent Application Laid-open No. 60-260769 and Utility Model Application No. 60-1
As shown in Japanese Utility Model No. 73648 or Japanese Utility Model Application No. 60-194145, a method is known in which a predetermined portion of the inner surface of a cast iron cylinder bore is subjected to hardening treatment such as quenching. Recently, N
A method of locally overlaying corrosion-resistant and wear-resistant alloys such as i-based alloys is known, and when this method is actually applied, it is necessary to weld the entire surface of the part where wear is likely to progress, that is, on the compression ring. The entire required width from the dead center to near the top dead center of the oil ring is overlaid with the same corrosion-resistant and wear-resistant alloy.

Problems to be Solved by the Invention Among the conventional measures against cylinder bore wear as described above, the method of applying hardening treatment such as quenching only takes into account wear caused by mechanical sliding friction, and does not cause sulfuric acid dew point corrosion. Therefore, it has been difficult to sufficiently suppress the progress of corrosive wear.

On the other hand, the method of overlaying corrosion-resistant and wear-resistant alloys such as Ni-Qr alloys is effective against sulfuric acid dew point corrosion, and therefore reduces wear significantly compared to hardening treatments such as quenching as described above. The amount can be reduced. However, in this conventional method, the same material is used to build up the entire necessary width from the vicinity of the top dead center of the compression ring to the vicinity of the top dead center of the oil ring, which has the following disadvantages.

In other words, the wear mechanism is different between each piston ring near the top dead center of the compression ring and near the top dead center of the oil ring, so it is difficult to select the optimal material for wear caused by all rings. The reality is that this is difficult, and as a result, there are limits to the ability to prevent wear.

To explain this point in more detail, wear on the inner surface of the cylinder bore is caused by sulfuric acid dew point corrosion and mechanical sliding friction. Of these, sulfuric acid dew point corrosion is caused by sulfur (S ), the SO2 gas generated by combustion is caused by V205 and Fe attached to the combustion chamber wall.
It changes to 303 through the catalytic action of oxides such as 2O3, and the resulting SO3 reacts with N20 produced by combustion, condensing as sulfuric acid on the low-temperature cylinder head wall.
Furthermore, the sulfuric acid flows from the cylinder head wall surface into the cylinder bore inner surface, corroding the cylinder bore inner surface. In this way, sulfuric acid dew point corrosion is caused by sulfuric acid flowing from the cylinder head side into the cylinder bore, and each piston ring top dead center Among these, it has the effect of accelerating wear the most near the top dead center of the compression ring, which is close to the cylinder head. On the other hand, near the top dead center of the oil ring, which is far from the cylinder head, the influence of sulfuric acid dew point corrosion is not so great, and wear is mainly caused by mechanical sliding friction.Especially in general internal combustion engines, the surface pressure of the oil ring is is set to be much higher than the surface pressure of the compression ring, so the influence of mechanical sliding friction is strong. Therefore, if the mechanism of wear on the inner surface of the cylinder bore is divided into corrosive wear and mechanical wear, corrosive wear is predominant near the top dead center of the compression ring, while mechanical wear is predominant near the top dead center of the oil ring. .

By the way, in order to improve the mechanical wear resistance of corrosion-resistant and wear-resistant alloys such as Ni-based alloys, which are overlaid to prevent cylinder bore wear, it is necessary to precipitate hard particles such as carbides and silicides. It is effective to increase the height. However, in this case, solid solution elements around carbides and silicides are consumed by the precipitation of hard particles, and the concentration of those solid solution elements that are effective in improving the corrosion resistance of the material decreases, resulting in a decrease in the corrosion resistance of the material. will decrease, so
Generally, it has been difficult to simultaneously improve mechanical wear resistance and corrosion resistance. Therefore, in the conventional method described above, if corrosion wear is emphasized and a build-up material with excellent corrosion resistance is selected, it becomes difficult to sufficiently prevent mechanical wear near the top dead center of the oil ring, and conversely, it becomes difficult to prevent mechanical wear near the top dead center of the oil ring. If a hard overlay material is selected with emphasis on physical wear, it will be difficult to sufficiently prevent corrosive wear near the top dead center of the compression ring, and in any case, it will be difficult to sufficiently prevent wear overall. Met.

Furthermore, as mentioned above, if the same material is used to build up the area from the top dead center of the compression ring to the top dead center of the oil ring, the width of the build-up must be considerably wide, and as a result, the cooling process during overlay welding Because the shrinkage stress at is large,
There was a problem that overlay weld bead cracking was likely to occur.

This invention was made against the background of the above circumstances, and is based on the premise of a cylinder bore for an internal combustion engine that prevents wear near the top dead center of each piston ring by overlaying a corrosion-resistant and wear-resistant alloy. It is possible to sufficiently prevent the progression of wear both near the top dead center of the compression ring, which is strongly affected by mechanical wear, and near the top dead center of the oil ring, which is most affected by mechanical wear. It is an object of the present invention to provide a cylinder bore that is easy to weld and that reduces the risk of cracking of the overlay weld bead.

Means for Solving the Problems The cylinder bore of the present invention basically consists of a portion of the cylinder bore that is to be overlaid, from near the top dead center of the compression ring to near the top dead center of the oil ring, as a highly corrosive and abrasive part. It is divided into parts that are highly abrasive and overlay welded with a material that matches the abrasion characteristics of each part.

Specifically, in the cylinder bore for an internal combustion engine of the present invention, a first corrosion-resistant and wear-resistant alloy is welded overlay near the top dead center of the compression ring on the inner surface of the cylinder bore, and a first corrosion-resistant and wear-resistant alloy is welded on the inner surface of the cylinder bore near the top dead center of the oil ring. A second corrosion-resistant and wear-resistant alloy having a different composition from the first corrosion-resistant and wear-resistant alloy is overlay welded, and the first corrosion-resistant and wear-resistant alloy has better corrosion resistance than the second corrosion-resistant and wear-resistant alloy. The present invention is characterized in that the second corrosion-resistant and wear-resistant alloy is an alloy that has better mechanical wear resistance than the first corrosion- and wear-resistant alloy.

Here, as the first corrosion-resistant and wear-resistant alloy and the second corrosion-resistant and wear-resistant alloy, it is desirable to use Ni-based alloys having mutually different compositions.

Furthermore, when a Ni-based alloy is used as each of the corrosion-resistant and wear-resistant alloys, the first corrosion-resistant and wear-resistant alloy to be overlaid near the top dead center of the cosylation ring is a Ni-based alloy with a relatively low C content, i.e. Carbide forming elements (Cr, Mo
1W, Nb, Ta, V, etc.) 1-30%, Si0.08
7%, 30.1 to 3.9%, and CO13 to 0.6%, and at least Cr among the carbide forming elements,
Contains 1 to 30% of one or two kinds of Mo, further contains one or two kinds of Fe0.1 to 30% and Cu0.1 to 2.3% as necessary, and the balance is Ni and unavoidable It is desirable to use a Ni-based alloy with a composition consisting of impurities, while the second corrosion-resistant and wear-resistant alloy to be overlaid near the top dead center of the oil ring has a higher carbon content than the first corrosion- and wear-resistant alloy. Ni-based alloys with a high content, i.e. carbide-forming elements (Cr, MOLW, Nb, Ta1V, etc.) 1-30%,
Si0.08~7%, 80.1~3.9%, C1.0~
2.0%, and contains 1 to 30% of at least one or both of Or and Mo among the carbide-forming elements, and further contains Fe 0.1 to 30%, Cu0.
Contains 1 to 2.3% of 11 types or 2 types, the balance being Ni
It is desirable to use a Ni-based alloy having a composition consisting of the following: and unavoidable impurities.

Function: As mentioned above, among the parts of the inner surface of the cylinder bore for internal combustion engines that are prone to wear, from near the top dead center of the compression ring to near the top dead center of the oil ring, wear near the top dead center of the compression ring is generated within the cylinder head. There is a strong tendency for corrosive wear due to sulfuric acid dew point corrosion caused by sulfuric acid, while there is a strong tendency for mechanical wear near the top dead center of the oil ring due to mechanical friction. Therefore, in the cylinder bore of the present invention, the vicinity of the top dead center of the compression ring and the vicinity of the top dead center of the oil ring are overlaid with corrosion-resistant and wear-resistant alloys having different compositions depending on the wear characteristics of the respective parts. In other words, the first corrosion-resistant and wear-resistant alloy used for the build-up near the top dead center of the compression ring has better corrosion resistance than the second corrosion-resistant and wear-resistant alloy used for the build-up near the top dead center of the oil ring. On the other hand, as the second corrosion-resistant and wear-resistant alloy near the top dead center of the oil ring, an alloy with a hard component composition that has better mechanical wear resistance than the first corrosion- and wear-resistant alloy is used. Use.

As mentioned above, N+-based alloys, which are typical corrosion- and wear-resistant alloys used for overlaying the inner surface of cylinder bores, have extremely high corrosion resistance and mechanical wear resistance with the same composition. Although it is practically difficult to achieve excellent corrosion resistance, it is important to have a component composition that has extremely excellent corrosion resistance even if it sacrifices some mechanical abrasion resistance. It is easy to obtain a component composition with extremely excellent properties. Therefore, as mentioned above, by changing the composition of the overlay alloy in the area near the top dead center of the compression ring, which has strong corrosive abrasion, and the overlay alloy in the area near the top dead center of the oil ring, which has strong mechanical abrasion. , the overlay near the top dead center of the compression ring has sufficient corrosion resistance to sufficiently prevent corrosion wear in that area, and the overlay alloy near the top dead center of the oil ring has sufficient mechanical wear resistance. This makes it possible to sufficiently prevent mechanical wear at that portion, thereby easily preventing wear at each portion near the top dead center of each piston ring to the maximum extent possible.

In addition, by separately overlaying the areas near the top dead center of the compression ring and the area near the top dead center of the oil ring, the width of each overlay bead is the same as the entire width from near the top dead center of the compression ring to near the top dead center of the oil ring. Compared to the case of overlaying with the same material, it is sufficient to be narrower, and therefore the shrinkage stress during the cooling process after overlay welding is reduced, reducing the possibility of bead cracking occurring.

Here, the 18th and 2nd corrosion-resistant and wear-resistant alloys used for overlay welding are typically Ni-based alloys, and the desirable component compositions of each are as described above, but the reasons for adding each alloy element and The reason for the desirable addition amount will be explained below.

Carbide-forming elements: Carbide-forming elements such as CrlMo, V, Nb, and Ta combine with C in the alloy to form carbides, contributing to increasing hardness and improving mechanical wear resistance. Furthermore, among these carbide-forming elements, Cr and MO particularly contribute to improving corrosion resistance. If the total amount of these carbide-forming elements is less than 1.0%, sufficient wear resistance cannot be obtained, and if the total amount of one or two of the carbide-forming elements is 1.0%.
If it is less than that, sufficient corrosion resistance cannot be obtained. On the other hand, if the total amount of these carbide-forming elements exceeds 30.0%, the toughness will decrease. Therefore, the total amount of carbide-forming elements is 1.0 to 3
It is preferable that Crl is within the range of 0.0%.
It is desirable that one or two types of Mo be contained in a total amount of 1.0% or more. Note that if the MO content exceeds 6.5%, bead cracking is likely to occur during cooling during overlay welding, so it is desirable that Moi is 6.5% or less when MO is added.

Si: Si is an element that imparts self-solubility to the alloy and forms a good slag during surface welding, thereby being effective in reducing oxide inclusions and pores in the build-up layer.

If the amount of Si added is less than 0.08%, the effect of imparting self-solubility will be small, while if it exceeds 7%, the toughness will decrease.

Therefore, the amount of Si added is preferably within the range of 0.08 to 7%.

B: Along with Si, B is also an element that imparts self-solubility to the alloy, forms a good slag during overlay welding, and is thereby effective in reducing oxide inclusions and pores in the overlay layer. If the amount of B added is less than 0.1%, sufficient self-solubility cannot be obtained;
If it exceeds 9%, toughness decreases. Therefore B is 0.1
It is preferably within the range of ~3.9%.

C: C is an element that combines with carbide-forming elements to form a hard carbide and contributes to improving mechanical wear resistance,
The higher the C content, the greater the amount of carbide precipitation and the higher the mechanical wear resistance. However, when carbides precipitate, they take in surrounding carbide-forming elements and reduce the alloy concentration around the carbides. Among carbide-forming elements, especially Cr, MO
is an element that has a remarkable effect on improving corrosion resistance in a solid solution state, but when the C content increases and the amount of carbide precipitation increases, Or and M become effective in improving corrosion resistance.

The amount of solid solution decreases around the carbide, making it impossible to fully exhibit corrosion resistance. Therefore, in the present invention, the first corrosion-resistant and wear-resistant alloy to be overlaid near the top dead center of the compression ring has a relatively small C content to fully exhibit corrosion resistance, and on the other hand, the first corrosion-resistant and wear-resistant alloy is overlaid near the top dead center of the oil ring. As the second corrosion-resistant and wear-resistant alloy, it is desirable to use one that has a relatively large C content to improve mechanical wear resistance. In the Ni-based alloy as the first corrosion-resistant and wear-resistant alloy, when C'' is less than 0.3%, carbide formation is extremely small. On the other hand, if it exceeds 0.6%, excellent corrosion resistance will not be exhibited, so it is preferably within the range of C0.3 to 0.6%. In addition, in the Ni-based alloy as the second corrosion-resistant and wear-resistant alloy, C
If the amount is less than 1.0%, it will not be possible to exhibit excellent mechanical wear resistance as a second corrosion-resistant and wear-resistant alloy that emphasizes mechanical wear resistance, while if it exceeds 2.0%, toughness will decrease. ,1
．． It is preferably within the range of 0 to 2.0%.

Fe: Fe has the effect of improving seizure resistance, and also has the meaning of reducing costs by reducing the amount of expensive Ni used.
It is added within the range of 0.1 to 30% as necessary. F
When e is less than 0.1%, these effects are small; on the other hand, when 30
%, the corrosion resistance deteriorates, so when adding Fe, the amount of Fe is preferably within the range of 0.1 to 30%. Note that as the amount of Fe increases, the corrosion resistance decreases, so it is preferable that Fe is about 10% or less, especially as the first corrosion-resistant and wear-resistant alloy used near the top dead center of the compression ring.

Cu: Cu is an element effective in improving corrosion resistance, and is added as necessary. However, if the amount of Cu is less than 0.1%, little improvement in corrosion resistance can be expected;
%, CU in the alloy will segregate during bead solidification after overlay welding, and hot cracking will likely occur. I want to do it Cu
When adding Cu, the range of Cu addition ranges from 0.1 to 2.3%.
Preferably within the range.

Embodiment [Embodiment 1] FIG. 1 shows an embodiment of the present invention applied to a cylinder bore of a diesel engine. Note that FIG. 1 shows a state in which the piston 1 is at the top dead center with respect to the cylinder bore 2. Also, the piston 1 has two pressure rings 3.
4 and one oil ring 5.

Position corresponding to compression ring 3.4 at top dead center position (i.e. compression ring top dead center position)
A groove 8 is formed along the circumferential direction on the inner surface of the cylinder bore, and alloy A as the first corrosion-resistant and wear-resistant alloy shown in Table 1 is applied to the groove 8 by laser overlay welding. The first overlay layer 6 is formed by overlay welding, and the inner surface of the cylinder bore at a position corresponding to the oil ring 5 at the top dead center position (i.e., the oil ring top dead center position) has a circumferential direction. A groove 9 is formed along the groove 9, and alloy B as a second corrosion-resistant and wear-resistant alloy shown in Table 1 is deposited along the circumferential direction by laser deposition welding. A second built-up layer 7 is formed by welding.

Table 1 Figure 2 shows the amount of corrosion of the alloys A and B, and Figure 3 shows the hardness of the alloys A and B. The amount of corrosion in Figure 2 is 80℃.
, is the corrosion depth when immersed in a 50% H2304 aqueous solution for 1 hour. Since Alloy A has a lower C content than Alloy B, its hardness is lower than that of Alloy B, and therefore its wear resistance against mechanical sliding wear is also lower. On the other hand, Alloy B has a higher C content than Alloy A, so it has high hardness and high wear resistance against mechanical sliding wear. It becomes an alloy phase,
Therefore, the corrosion resistance is inferior to Alloy A.

Fig. 4 shows the product 1 of the present invention in which alloy A is welded to the top dead center of the compression ring 3.4 and alloy B to the top dead center of the oil ring 5 as described above, and the product 1 in which only alloy A is welded. Wear ω at the top dead center of the compression ring 3, the top dead center of the compression ring 4, and the top dead center of the oil ring 5 for conventional product 1 with overlay welding and conventional product 2 with overlay welding of only alloy B. The results of each investigation are shown below.

As shown in Fig. 9, in conventional products 1 and 2, the entire surface from the top dead center of the compression ring 3.4 to the top dead center of the oil ring 5 is overlaid with the same alloy (A or B). In this way, the same build-up layer 14 is formed.

As shown in Fig. 4, if we compare the conventional product 1, which is overlaid with only alloy A, and the conventional product 2, which is overlaid with only alloy B, it is found that the compression ring 3.4 has excellent corrosion resistance at the top dead center position. Conventional product 1, which is overlaid with alloy A, has less wear than conventional product 2, which is overlaid with alloy B. This seems to be because the wear at the top dead center position of the compression ring 3.4 is strongly affected by the corrosion of H2304 caused by light oil combustion gas. On the other hand, at the top dead center position of the oil ring 5, conventional product 2, which is overlaid with alloy B, which has excellent mechanical wear resistance, is better than alloy A.
The amount of wear is less compared to conventional product 1, which is overlaid. This is thought to be because the wear at the top dead center of the oil ring is less affected by corrosion due to H2SO4 than the top dead center position of the compression ring, and is more affected by mechanical sliding wear.

- In the case of the product 1 of the present invention shown in Fig. 1, even at the top dead center position of the compression ring 3.4 as shown in Fig. 4,
We were able to reduce the amount of wear both at the top dead center position of the oil ring 5. Here, the present invention product 1 and the conventional product 2 are the same in that alloy B is overlaid at the top dead center position of the oil ring, but in the present invention product 1, the compression ring is overlaid at the top dead center position. By reducing wear, the wear caused by the compression ring dragging near the top dead center position of the oil ring is reduced, and therefore the amount of wear at the top dead center position of the oil ring is lower than that of conventional product 2, which was overlaid with only alloy B. It has decreased even more than before. The same applies to the wear at the top dead center position of the compression ring, and in the product 1 of the present invention, the wear at the oil ring top dead center position is reduced, so that the compression ring does not drag near the top dead center position of the compression ring. As a result, the amount of wear at the top dead center position of the compression ring is further reduced than in the case of conventional product 1 in which only alloy A is overlaid.

FIG. 5 shows the bead cracking incidence of the invention product 1 and the conventional product 1.2. In the conventional product 1.2, the entire width from the top dead center position of the compression ring 3.4 to the top dead center position of the oil ring 5 is overlaid with one bead of alloy A or B. However, in the product 1 of the present invention, the top dead center position of the combination ring 3.4 and the top dead center position of the oil ring 5 are made of a split bead that is built up separately. Shrinkage stress was reduced and bead cracking could be prevented.

[Example 2] Similar to Example 1, the present invention was applied to the cylinder bore of a diesel engine as shown in FIG. Here, as the first build-up layer 6 at the top dead center position of the combination ring 3.4 on the inner surface of the cylinder bore, alloy A having the same composition as in Example 1 is used as shown in Table 2, and the oil ring 5
As the second build-up layer 7 at the top dead center position, alloy A', which has improved hardness by increasing only the C suspension compared to alloy A, was used. In this case, Alloy A' was the same as Alloy A in terms of other additive elements from the viewpoint of weldability and the like. The corrosion resistance and hardness of alloy A1A' are shown in Table 2.

Table 2 As shown in Table 2, Alloy A' has improved hardness compared to Alloy A by increasing the C content, but its corrosion resistance is inferior to Alloy A for the reasons mentioned above.

FIG. 6 shows product 2 of the present invention in which alloy A and alloy A' were overlaid as described above, conventional product 1 in which only alloy A was overlaid, and conventional product 3 in which only alloy A' was overlaid. Compression ring 3 top dead center, compression ring 4
The results of investigating the wear amount at the top dead center and the oil ring 5 at the top dead center are shown.

As shown in FIG. 6, the product 2 of the present invention is also superior in wear at each top dead center position of the compression ring 3.4 and wear at the top dead center position of the oil ring 5 compared to the conventional product. It is clear that the number of people living in Japan is decreasing.

[Other Examples] In the cylinder bore 2 shown in FIG. 7, the oil ring 5 is inserted from the top dead center position of the compression ring 3.4.
A common groove 1O is formed toward the top dead center position, and a first groove 10 made of a first corrosion-resistant and wear-resistant alloy with excellent corrosion resistance is formed at a position corresponding to the top dead center of the compression ring 3.4. A second build-up layer 7 made of a second corrosion-resistant and wear-resistant alloy with excellent mechanical wear resistance is formed at a position corresponding to the top dead center of the oil ring 5. In the case of the embodiment shown in FIG. 7, grooving on the inner surface of the cylinder bore only needs to be performed once, so that the number of processing steps can be reduced and costs can be reduced.

In the cylinder bore shown in FIG. 8, grooves 11, 12, and 13 are formed at the top dead center position of the compression ring 3, the top dead center position of the compression ring 4, and the top dead center position of the oil ring 5, respectively. Cage, groove 1
A build-up layer 6.6 made of a first corrosion-resistant and wear-resistant alloy with excellent corrosion resistance is formed in each of the grooves 1 and 12.
A second meat @MV made of a second corrosion-resistant and wear-resistant alloy with excellent mechanical wear resistance is formed in the portion 3.

In the embodiment shown in FIG. 8, the width of each rod can be made smaller than in the case shown in FIG. 1, so that the occurrence of bead cracking can be further reduced.

In Example 1, the overlay welding was performed using a laser, but the heat source for the overlay means is not limited to the laser, and it is also possible to use a TIG arc, plasma arc, electron beam, etc. Of course.

Also, as a material for overlaying, Ni! Of course, the material is not limited to alloys, and other alloys may also be used.

Effects of the Invention In the cylinder bore for an internal combustion engine of this invention, the area near the top dead center of the compression ring, which is highly susceptible to corrosion and abrasion, and the area near the top dead center of the oil ring, which is highly resistant to mechanical abrasion, are overlaid with a different corrosion-resistant and wear-resistant alloy. Therefore, a corrosion-resistant and wear-resistant alloy with extremely excellent corrosion resistance is overlaid near the top dead center of the compression ring, and a corrosion-resistant and wear-resistant alloy with extremely excellent mechanical wear resistance is overlayed around the top dead center of the oil ring. By doing so, it is possible to significantly reduce the amount of wear at any part from the top dead center of the compression ring to the top dead center of the oil ring, and the material for overlay welding of each part has both corrosion resistance and mechanical wear resistance. Selection of overlay welding materials becomes easier as there is no need to choose superior materials.
Furthermore, since the width of the overlay bead can be made small, shrinkage stress during cooling during overlay welding can be reduced, thereby reducing the occurrence of bead cracking.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view showing the main part of an example of the cylinder bore of the present invention, Fig. 2 is a graph showing the corrosivity of alloys A and B used in Example 1, and Fig. 3 is the same (Example 1). Alloy A used
, B. FIG. 4 is a graph showing the amount of wear at the top dead center position of each piston ring of the invention product 1 and conventional product 1.2 in Example 1. FIG. Fig. 6 is a graph showing the bead crack occurrence rate of the invention product 1 and the conventional product 1.2 in Example 2, and Fig. 6 shows the wear amount at the top dead center position of each piston ring of the invention product 2 and the conventional product 1.3 in Example 2. FIGS. 7 and 8 are longitudinal sectional views showing main parts of other examples of the cylinder bore of the present invention, and FIGS.
The figure is a longitudinal sectional view showing a main part of an example of a conventional cylinder bore. 1...Piston, 2...Cylinder bore, 3.4
...Compression ring, 5...Oil ring, 6...Build-up layer made of first corrosion-resistant and wear-resistant alloy, 7
...A build-up layer made of a second corrosion-resistant and wear-resistant alloy.

Claims (3)

[Claims] (1) A first corrosion-resistant and wear-resistant alloy is overlay welded near the top dead center of the compression ring on the inner surface of the cylinder bore, and a material different from the first corrosion-resistant and wear-resistant alloy is welded near the top dead center of the oil ring on the inner surface of the cylinder bore. A second corrosion-resistant and wear-resistant alloy of the composition is overlay welded, and the first
The corrosion-resistant and wear-resistant alloy is an alloy that has better corrosion resistance than the second corrosion- and wear-resistant alloy, and the second corrosion- and wear-resistant alloy is an alloy that has better mechanical wear resistance than the first corrosion- and wear-resistant alloy. A cylinder bore for an internal combustion engine characterized by being used. (2) The cylinder bore for an internal combustion engine according to claim 1, wherein Ni-based alloys having different compositions are used as the first corrosion-resistant and wear-resistant alloy and the second corrosion-resistant and wear-resistant alloy. (3) As the first corrosion-resistant and wear-resistant alloy, carbide-forming elements 1 to 30%, Si 0.08 to 7%, B 0.1 to 3.9
%, C0.3 to 0.6%, and at least one or two of the carbide-forming elements Cr and Mo.
Contains ~30%, and further Fe0.1-30 as necessary
%, containing one or two types of Cu0.1 to 2.3%,
N with a component composition in which the remainder is Ni and unavoidable impurities
An i-based alloy is used, and as a second corrosion-resistant and wear-resistant alloy, carbide-forming elements 1 to 30%, Si 0.08 to 7%, B
0.1 to 3.9%, C1 to 2%, and at least one or two of Cr and Mo among the carbide forming elements.
Contains 1 to 30% seeds, and if necessary Fe0.1
30% of Cu, 0.1 to 2.3% of Cu, and one or two of them, with the remainder being Ni and unavoidable impurities. Cylinder bore for internal combustion engines.