JPS63195366A - 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 an alloy near the top dead center of compression rings, and forming a quenching-hardened layer near the top dead center of an oil ring, at the inner surface of the cylinder bore. CONSTITUTION:At the inner surface of a cylinder bore 2, an anticorrosive and antiabrasive alloy 6 is swelled and welded near the top dead center of compression rings 3 and 4, while a quenching-hardened layer 7 is formed near the top dead center of an oil ring 5. Therefore, the abrasion can be suppressed sufficiently both near the top dead center of the compression rings where the corrosive abrasion is produced strongly and near the top dead center of the oil ring where the mechanical abrasion is produced strongly.

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 of the bore surface near the top dead center of a piston ring. .

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 friction due to the piston ring and carbon suit, and at the same time is subjected to sulfuric acid dew point corrosion caused by 802 contained in the combustion gas, and these act synergistically to cause local It is known that wear progresses rapidly. 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 countermeasures against the wear of cylinder bores as described above, the method of applying hardening treatment such as quenching only takes into account wear caused by mechanical surrounding kinetic friction. Therefore, it has been difficult to sufficiently suppress the progress of corrosive wear.

On the other hand, the method of overlay welding corrosion-resistant and wear-resistant alloys such as Ni-based alloys is effective against sulfuric acid dew point corrosion, and therefore the amount of wear is significantly reduced compared to hardening treatments such as quenching as described above. It 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 opening dynamic friction. Of these, sulfuric acid dew point corrosion is caused by sulfur (S 302 gas produced by combustion due to ) is combustion.

It is converted to 803 by the catalytic action of fluorides such as V205 and Fe2O3 attached to the chamber wall, and the 303 reacts with H2O generated by combustion to condense as sulfuric acid on the low-temperature cylinder head wall. This is a phenomenon in which sulfuric acid dew point corrosion occurs when sulfuric acid flows from the wall surface into the cylinder bore inner surface and corrodes the inner surface of the cylinder bore.In this way, sulfuric acid dew point corrosion is caused by sulfuric acid flowing from the cylinder head side into the cylinder bore, so it is particularly It has the greatest effect in accelerating wear near the top dead center of the compression ring near 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 corrosion-resistant and wear-resistant alloys such as Ni-based alloys that are overlaid to prevent cylinder bore wear, in order to improve mechanical wear resistance, hard particles such as carbides and desilicates are precipitated to increase the hardness. It is effective to increase the 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 combination ring.In any case, it is important to sufficiently prevent wear in total. was difficult.

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-mentioned circumstances, and the present invention has been made in view of the above-mentioned circumstances. It is an object of the present invention to provide a cylinder bore that can sufficiently prevent the progress of wear and reduce the risk of cracking of the overlay weld bead as in the conventional overlay welding method.

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 the treatment is optimized for the wear characteristics of each part.

Specifically, the cylinder bore for an internal combustion engine of this invention is
A corrosion-resistant and wear-resistant alloy is welded overlay on the inner surface of the cast iron cylinder bore near the top dead center of the compression ring, and a hardened layer is formed near the top dead center of the oil ring on the inner surface of the cylinder bore. .

Here, as the corrosion-resistant and wear-resistant alloy, it is desirable to use a Ni-based alloy that has particularly excellent corrosion resistance.

Furthermore, when using a Ni-based alloy as each corrosion- and wear-resistant alloy, the Ni-based alloy may be a Ni-based alloy with a relatively low C content, that is, a Ni-based alloy containing carbide-forming elements (Cr, Mo, etc.).
, W, Nb5Ta, V, etc.) 1-30%, s;o, oa~
7%, 80.1 to 3.9%, and C013 to 0.6%, and as the carbide forming element, at least Qr,
Contains 1% or more of one or both of Mo, and further contains 1 to 30% of FeO and 1 to 2.3% of CuO as necessary.
It is desirable to use a Ni-based alloy having a composition containing one or two species and the remainder consisting of Ni 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 the sulfuric acid used, while there is a strong tendency for mechanical wear near the top dead center of the oil ring due to mechanical sliding friction. Therefore, in the cylinder bore of this invention, the area near the top dead center of the compression ring is mainly overlaid with a corrosion-resistant and wear-resistant alloy that has excellent corrosion resistance, and the area near the top dead center of the oil ring is formed with a hardened layer that has excellent mechanical wear resistance. are doing.

Although the hardened layer of cast iron by quenching has extremely excellent mechanical wear resistance as described above, its corrosion resistance is not particularly improved compared to the cast iron base material. On the other hand, as mentioned above, Ni-based alloys, which are typical corrosion- and wear-resistant alloys used for overlaying the inner surface of cylinder bores, have both corrosion resistance and mechanical wear resistance with the same composition. Although it is practically difficult to achieve extremely high corrosion resistance, it is relatively easy to achieve a component composition that has extremely high corrosion resistance even if the mechanical abrasion resistance is slightly sacrificed. Therefore, as mentioned above, overlay is applied only to the area near the top dead center of the compression ring, which is highly susceptible to corrosion and abrasion, and by using an alloy with extremely high corrosion resistance as the overlay alloy, it is possible to build up the top dead center of the compression ring. On the other hand, by forming a quenched hardened layer near the top dead center of the oil ring, it provides sufficient mechanical wear resistance and sufficiently prevents mechanical wear at that part. This makes it easy to prevent wear at each part of each piston ring near the top dead center to the maximum extent possible. In other words, according to this invention, it has become possible to significantly reduce the total wear compared to either the case of applying overlay alone or the case of applying hardening alone. be.

In addition, since overlay welding is performed only near the top dead center of the compression ring, the overlay bead width is different from the conventional method in which the entire width from around the top dead center of the compression ring to around the top dead center of the oil ring is overlaid with the same material. As a result, the shrinkage stress during the cooling process after overlay welding is reduced, reducing the risk of bead cracking.

Here, N is the corrosion-resistant and wear-resistant alloy used for overlay welding.
An i-based alloy is typical, and its desirable composition is as described above, but the reason for adding each alloying element and the reason for the desirable addition amount will be explained below.

Carbide-forming elements: Carbide-forming elements such as Or, Mo, V, Nb, and Ta combine with C in the alloy to form carbides, contributing to increasing hardness and improving mechanical wear resistance. Further, 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 desirable that Qr be within the range of 0.0%, and among them, Qr,
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 MoC content exceeds 6.5%, bead cracking is likely to occur during cooling during build-up welding, so when Mo is added, it is desirable to keep the MoI below 6.5%.

Sl:3i is an element that imparts self-fluxability to the alloy and forms a good slag during build-up welding, thereby being effective in reducing oxide inclusions and pores in the build-up layer.

If the amount of 3i added is less than O or Oa%, the effect of imparting self-solubility will be small, while if it exceeds 7%, the toughness will decrease.

Therefore, the amount of 81 added is preferably within the range of 8-7% O.

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 8 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 hard carbides and contributes to improving mechanical wear resistance. Increased 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 and M
O is an element that has a remarkable effect on improving corrosion resistance in a solid solution state, but if the C content increases and the amount of carbide precipitation increases, the solid solution a of Cr and Mo, which is effective in improving corrosion resistance, becomes carbide. The corrosion resistance decreases around , making it impossible to fully demonstrate corrosion resistance. Therefore, in the present invention, it is desirable to use a corrosion-resistant and wear-resistant alloy overlaid near the top dead center of the compression ring that has a relatively small C content to fully exhibit corrosion resistance. However, Cm is 0.3%
If it is less than 0.6%, the amount of carbide produced will be extremely small, and therefore mechanical wear resistance will be insufficient even as a corrosion-resistant and wear-resistant alloy that emphasizes corrosion resistance.On the other hand, if it exceeds 0.6%, excellent corrosion resistance will not be exhibited. It is preferably within the range of 0.6%.

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
If Fe is added, the corrosion resistance decreases, so when Fe is added, Fe is preferably within the range of 0.1 to 30%. Note that as the matrix of Fe increases, the corrosion resistance decreases, so as a corrosion-resistant and wear-resistant alloy used near the top dead center of the compression ring, the Fe content is preferably about 10% or less.

Cu: Cu is an element effective in improving corrosion resistance, and is added as necessary. However, if Cu is less than 0.1%, little improvement in corrosion resistance can be expected; on the other hand, if Cu content is less than 0.1%,
%, Cu in the alloy will segregate during bead solidification after overlay welding, and hot cracking will likely occur. Therefore, Cu
When adding Cu, the amount of Cu added is preferably within the range of 0.1 to 2.3%.

Embodiment [Embodiment 1] FIG. 1 shows an embodiment of the present invention applied to a cast iron 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. The piston 1 also has 2* compression rings 3.4 and one oil ring 5.

Compression ring at piston top dead center position 3.4
A groove 8 is formed along the circumferential direction on the inner surface of the cylinder bore at a position corresponding to (i.e., the top dead center position of the compression ring).
is formed in the groove 8, and alloy A having the composition shown in the upper row of Table 1 is overlay welded by laser overlay welding to form overlay m6, and the piston A hardened layer 7 is formed by laser hardening along the circumferential direction on the inner surface of the cylinder bore at a position corresponding to the oil ring 5 at the top dead center position (that is, the oil ring top dead center position). The composition of cast iron, which is the base material of the cylinder bore, is as shown in the lower part of Table 1.

Table 1 Unit: il1% Fig. 2 shows the amount of corrosion of the hardened layer of the overlay welding alloy A and cast iron, and Fig. 3 shows the hardness of the alloy A and the hardened layer. The amount of corrosion in Figure 2 is 80℃,
It is shown as the corrosion depth when immersed in 50% H2SO4 aqueous solution for 1 hour. As is clear from Figures 2 and 3, overlay welding alloy A has much better corrosion resistance than the quenched hardened layer, but its hardness is lower than the quenched hardened layer, so it suffers from mechanical sliding wear. The wear resistance is also lower than that of the quenched hardened layer.

Here, in order to improve the hardness of the overlay welding alloy A, if the amount of precipitated hard particles such as carbides is increased by increasing the C content, etc., when the hard particles precipitate, the surrounding alloy Since the elements Cr and Mo are incorporated, the surroundings of the hard particles become a low-alloy phase, resulting in a decrease in corrosion resistance. Therefore, in this embodiment, an overlay welding alloy A is used which has a relatively small amount of C so as to exhibit sufficient corrosion resistance. On the other hand, the quenched hardened layer has inferior corrosion resistance compared to the overlay welding alloy A, but has a high hardness and excellent mechanical wear resistance.

Fig. 4 shows a product 1 of the present invention in which alloy A is overlay welded at the top dead center position of the compression ring 3.4 and a quenched hardened layer is formed at the top dead center position of the oil ring 5 as described above.
For conventional product 1 in which only overlay welding was performed on the alloy and conventional product 2 in which only a quenched hardened layer was formed, the top dead center of compression ring 3 and the compression ring 4
The results of examining the amount of wear at the top dead center and the wear amount at the top dead center of the oil ring 5 are shown. Note that the conventional products 1 and 2 have a compression ring 3. as shown in FIG.
The entire surface from the top dead center of 4 to the top dead center of oil ring 5 is overlay welded with the same alloy (A or B), or the entire surface is quenched and hardened to have the same overlay pattern or A hardened layer 14 is formed thereon.

As shown in Fig. 4, if we compare the conventional product 1, in which only alloy A was overlaid, and the conventional product 2, in which only a quench hardened layer was formed, at the top dead center position of the compression ring 3.4, the corrosion resistance Conventional product 1, which is overlaid with Alloy A, which has excellent properties, has a much smaller amount of wear than conventional product 2, which has a quenched hardened layer. 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 H2SO4 caused by the gas oil combustion gas. On the contrary, oil ring 5
At the top dead center position, conventional product 2, which has a quenched hardened layer with excellent mechanical wear resistance, is better than conventional product 1, which has a hardened layer built up on the alloy.
The amount of wear is less compared to This is thought to be because the wear at the top dead center of the oil ring is less affected by corrosion due to H2304 than the top dead center position of the compression ring, and is more affected by mechanical (verbal and behavioral) wear.

On the other hand, 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.
Wear m was able to be reduced 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 a quenched hardened layer is formed at the top dead center position of the oil ring, but in the present invention product 1, the compression ring at the top dead center position is the same. By reducing wear due to the overlay of Alloy A, 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 reduced by forming a hardened layer. This is a further decrease compared to conventional product 2, which had only 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 top dead center position of the oil ring is reduced due to the formation of a quenched hardened layer. Wear due to dragging near the point position is reduced, and therefore the amount of wear at the top dead center position of the compression ring is further reduced compared to the case of conventional product 1 in which only alloy A was overlaid.

Furthermore, when the bead cracking incidence of the present invention product 1 and the conventional product 1 was investigated, the following results were obtained.

In other words, in the conventional product 1, in which 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 was overlaid with one bead of alloy, the bead crack occurrence rate was 20%. On the other hand, in product 1 of the present invention, overlay welding is performed only at the top dead center position of the combination ring 3.4, so the bead width is narrow, so the shrinkage stress due to cooling is reduced, and the incidence of bead cracking is reduced. It became 0%.

[Example 2] Similar to Example 1, the present invention was applied to the cylinder bore of a diesel engine as shown in FIG. Here, alloy B shown in the middle row of Table 1 is used as the build-up layer 6 at the top dead center position of the combination ring 3.4 on the inner surface of the cylinder bore, and alloy B shown in the middle row of Table 1 is used at the top dead center position of the oil ring 5. A hardened layer 7 was formed in the same manner.

Figure 5 shows the compression ring 3.4 as described above.
Invention product 2 in which Alloy B is overlaid at the top dead center position and a quenched hardened layer is formed at the top dead center position of the oil ring 5, Conventional product 3 in which only Alloy B is overlaid, and only the quenched hardened layer is overlaid. Regarding conventional product 2, which formed compression ring 3
The results of examining the amount of wear at the top dead center, the top dead center of the compression ring 4, and the top dead center of the oil ring 5 are shown.

As shown in FIG. 5, 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. However, the metal @welded alloy B used in the invention product 2 has a higher C content than the overlay alloy A used in the invention product 1 of Example 1, and therefore has inferior corrosion resistance when compared to the alloy. Compression ring 3.
The amount of wear at the top dead center position of No. 4 is larger than that of Invention No. 1.

Furthermore, when the bead crack occurrence rate was investigated for the present invention product 2 and the conventional product 3, it was 100% for the conventional product 3, but it was 0% for the present invention product 2, indicating that the occurrence of bead cracks can be prevented. was confirmed.

[Other Example 1] The cylinder bore 2 shown in FIG. 6 is irradiated with a laser beam having a width wider than the welding bead width at the same time as overlay welding is performed to form the overlay layer 6 and the quenched hardened layer 7. This was done at the same time as the formation of .

In the case of the embodiment shown in FIG. 6, since the inner surface of the cylinder bore only needs to be treated once, it is possible to reduce the number of steps and reduce costs.

In the cylinder bore shown in FIG. 7, grooves 11 and 12 are formed at the top dead center position of the compression ring 3 and the top dead center position of the compression ring 4. A thick layer 6.6 made of an excellent corrosion-resistant and wear-resistant alloy is formed, and a quenched hardened layer 7 is formed at the top dead center position of the oil ring 5. In the embodiment shown in FIG. 7, the width of each build-up bead can be made even smaller than that 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 overlay is not limited to the laser, and TIG arc, plasma arc, electron beam, etc. may also be used. Of course. Further, the hardening is not limited to laser hardening, and it goes without saying that induction hardening or the like may be applied.

Further, the overlay material is not limited to the Ni-based alloy as in each of the above embodiments, and it goes without saying that other types of alloys may be used.

Effects of the Invention In the cylinder bore for an internal combustion engine of the present invention, the compression ring near the top dead center is welded with a corrosion-resistant and wear-resistant alloy, and a quenched hardened layer is formed near the oil ring top dead center. The area near the top dead center of the compression ring, which has strong corrosion resistance, is protected from wear by a built-up layer of corrosion-resistant and wear-resistant alloy that has extremely high corrosion resistance, and the area near the top dead center of the oil ring, which has strong mechanical abrasion resistance, has extremely high mechanical abrasion resistance. Since wear can be prevented by the excellent quenched hardened layer, the amount of wear can be significantly reduced at any part from the compression ring top dead center to the oil ring top dead center. It is no longer necessary to choose a material with excellent corrosion resistance and mechanical wear resistance, making it easier to select a material for overlay welding.Furthermore, the width of the overlay bead can be made smaller, making overlay welding easier. By reducing the shrinkage stress during cooling, the occurrence of bead cracking can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view showing a main part of an example of the cylinder bore of the present invention, Fig. 2 is a graph showing the corrosivity of the hardened layer of alloy A and cast iron used in Example 1, and Fig. 3 is the same. A graph showing the hardness of the hardened layer of alloy A and cast iron used in Example 1. Figure 4 shows the wear at the top dead center position of each piston ring of the invention product 1 and conventional product 1.2 in Example 1. 5 is a graph showing the amount of wear at the top dead center position of each piston ring of the invention product 2 and conventional product 2.3 in Example 2, and FIGS. 6 and 7 are the graphs of the invention, respectively. FIG. 8 is a vertical cross-sectional view showing a main part of another example of a conventional cylinder bore. 1...Piston, 2...Cylinder bore, 3.4
...Compression ring, 5...Oil ring, 6...Build-up layer made of corrosion-resistant and wear-resistant alloy, 7...
Quenched hardened layer. m 'r', も曵 −

Claims (3)

[Claims] (1) A 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 made of cast iron, and a hardened layer is formed near the top dead center of the oil ring on the inner surface of the cylinder bore. Cylinder bore for internal combustion engines. (2) The cylinder bore for an internal combustion engine according to claim 1, wherein a Ni-based alloy is used as the corrosion-resistant and wear-resistant alloy. (3) As the corrosion-resistant and wear-resistant alloy, carbide-forming elements 1 to
30% (However, at least C among the carbide-forming elements)
Contains 1% or more of one or both of r and Mo)
, Si0.08-7%, B0.1-3.9%, C0.3
~0.6%, and further Fe0.1~ as necessary
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.