JPS6036644A - Composite cylinder liner - Google Patents

Abstract

PURPOSE:To obtain a tough composite cylinder liner with superior wear resistance and seizing resistance by uniting an outer layer of spheroidal graphite cast iron with superior toughness and an inner layer of cast iron with superior wear resistance and seizing resistance to one body by melt bonding while interposing an intermediate layer of cast iron for improving the melt-bonded part between the layers. CONSTITUTION:An outer layer (a) of spheroidal graphite cast iron, an intermediate layer (c) of cast iron and an inner layer (b) of special cast iron are successively cast and united to one body by melt bonding to obtain the desired composite cylinder liner. The cast iron of the layer (a) contains, by weight, 2.6- 4.0% C, 1.5-3.5% Si, 0.2-1.0% Mn, <=0.3% P, <=0.04% S, 0.02-0.1% Mg and restricted amounts of Ni, Cr, etc. and has a structure consisting essentially of spheroidal graphite and a pearlite matrix. The cast iron of the layer (c) contains 2.0-4.0% C, 0.8-3.0% Si, 0.4-1.2% Mn, <=0.6% P, <=0.2% S, <=0.05% Mg and restricted amounts of Ni, Cr, etc. The cast iron of the layer (b) contains 2.5- 4.0% C, 0.8-2.5% Si, 0.3-1.5% Mn, 0.05-1.5% P, <=0.3% S and restricted amounts of Ni, Cr, etc.

Description

[Detailed description of the invention] The present invention relates to the provision of tough composite cylinder liners.

Cylinder liners used in internal combustion engines must have wear resistance and seizure resistance because they must slide together with piston rings and maintain airtightness. For this purpose, conventional cylinder liners have been mainly used with special cast iron containing A-type graphite and wear-resistant % of Cr%B, P, ■, Mu, Nb, etc. It is being used.

However, with the recent increase in the size of internal combustion engines and the demand for lighter weight and lower fuel consumption, the above-mentioned conventional materials have become insufficient in terms of strength, and there is a strong desire for the same strength.

For the same purpose of increasing strength, it is possible to select a liner material with high strength, but this may impair the abrasion resistance and seizure resistance, which are the essential characteristics of cylinder liners. , there are practical limits.

5 It is also effective to increase the thickness of the liner, but in this case it goes against the objective of reducing weight.

Therefore, the outer layer was made of a material with excellent toughness, and the inner metal (
1) Excessive cementite in the welded area, which causes problems in terms of strength and heat conduction, and (11) The problem of changing the inner layer material due to mixing and diffusion of the outer layer material into the inner layer material. It is hoped that this problem will be resolved.

By the way, when analyzing the usage conditions and causes of damage to cylinder liners, we find that (1) The only part that requires wear resistance and seizure resistance is the part that contacts the piston ring, that is, the inner surface of the liner.

(11) Damage to the cylinder liner starts from its outer surface.

It is known that

The present invention aims to achieve the above objectives by applying an unprecedented composite technology to the cylinder liner.

That is, the composite cylinder liner of the present invention has an inner layer (near the inner surface) made of a special cast iron material with a specific chemical composition that has excellent wear resistance and seizure resistance, and an outer layer (near the outer surface) made of a special cast iron material with a specific chemical composition. It is made of a specific superior spheroidal graphite cast iron material, and the intermediate layer between the inner layer and the outer layer is made of a special cast iron material with a specific chemical composition to improve the interlayer welds and make the inner layer material sound. , the outer layer and the intermediate layer, and the intermediate layer and the inner layer are metallurgically welded and integrated, respectively, and the desired strength is improved without impairing the required wear resistance and seizure resistance as a whole, and the interlayer welds are We succeeded in improving this and making the inner layer material sounder.

The present invention will be explained in detail below.

The composite cylinder liner of the present invention has a structure as shown in FIG. That is, the outer layer a is made of a spheroidal graphite cast iron material with excellent toughness, which will be detailed later.
The inner layer is made of a special cast iron material with a specific chemical composition that has excellent seizure resistance and wear resistance, and the middle layer C has a specific chemical composition for improving the welds between each layer and making the inner layer material sound. The outer layer and the intermediate layer, and the intermediate layer and the inner layer are metallurgically welded and integrated, respectively.

The multilayer composite cylinder liner of the present invention can be easily manufactured by centrifugal casting. That is, first, after the outer layer is cast, the intermediate layer material is cast at an appropriate timing, the inner layer material is cast at an appropriate timing, and each sound is melted and integrated.

Note that the centrifugal force casting method can be applied to any of the horizontal type, inclined type, and vertical type.

The spheroidal graphite cast iron material forming the outer layer of the composite cylinder liner of the present invention will be briefly described.

The present invention is characterized by using a material having the following component composition as a liner outer layer material having excellent strength. That is, the outer layer is C2,6~4.096.5i in weight%
L5-3.5%, Mn 0.2-1.096, PO,
5if or less, S O, 04% or less, Mg O, 02~0
．． 1%, Ni 2.5% or less, cr O, 8% or less,
Mo 0.6% or less, 8n O, 39t5 or less, rare earth elements 11.1% or less, C! u 4.0% or less, AZ
', 1N aperture, 'fGO-36644 (3) Oa,
Ba, Sr no 11 cases; I 2 tumor or more total 0
．． 2% or less, including 1 or more 11:21 or more,
It is a spheroidal graphite cast iron material mainly consisting of spheroidal graphite and pearlite base, with the remainder being Fe and normal impurities.

Therefore, the chemical components, microscopic structure, etc. of the above-mentioned specific lunar substance will be explained in detail in 14 below.

(1) Chemical composition 0: 2.6 to 4.096 The material of the outer layer of spheroidal graphite cast iron is υ(
However, a small amount of cementite crystallization is not a problem), and toughness is particularly important. However, if the C content is less than 6%, the castability deteriorates and the amount of cementite crystallized increases, and if the content exceeds 9.096%, which makes the material brittle, casting defects are likely to occur.

8t: 1-5 to 6.5% 81 has the effect of promoting graphitization, and in the case of this material in which Mgffi is added as a graphite nodularizing agent, if it is less than 1.5%, the amount of cementite crystallization will be large. This is because it becomes brittle. However, when the value exceeds 3.596, the 9 bases become ferrite and the yield strength deteriorates, and the 81 melted into the ferrite makes the ferrite brittle.

Mn: 0.2 to 1.0% Kn usually combines with S to remove the negative effects of 8, stabilize the base barfit, and increase strength. Mn□, 2
If it is less than 1.0%, this effect cannot be expected, and if it exceeds -1.0%, it will become brittle.

P: 0.596 or less P increases the fluidity of the molten metal, but it also generates phosphorus in the material, making the material brittle. This effect increases as the P content increases, but the upper limit is set at 0.3% as a range that does not cause any actual damage. Although the P content is advantageous in terms of low root toughness, in practice it is difficult to reduce P to 0.014 or less.

8: 0.0496 or less S, like P, is generally understood to be an impurity element [7] and deteriorates mechanical properties. Since it has the effect of inhibiting the spheroidization of dusted graphite, it should be kept at 0.0410% or less.

8 (g: 0.02-0.1% MgF'f Of course, it is added to make the graphite spheroidized 1
However, if it is less than 0.02%, the effect is insufficient, and if it exceeds -0.1%, it is undesirable because it tends to cause chilling effect of Mg and Vf formation defects such as dross. .

Ni, Or, No%5n Ni, (3r, Mo, Sn are effective in improving toughness, Ni 2.596 or less, Or 0.811
The liner can be made tougher by containing one or more of Mo below 0.64 and SnO below 34.

The effect of each and the reason for limiting the ingredients will be explained below.

Ni: 2.596 or less Ni acts effectively on graphitization and strengthening the base, but 2.5
If it exceeds %, it is not only disadvantageous in terms of economic efficiency, but also
Hardened structures (bainite, martensite) and untransformed structures are likely to occur, which does not meet the purpose of the outer layer material, so AI! It is. Note that a content of 0.5% or more is effective.

Or: g, B% or less Or acts to strengthen the base and stabilize cementite. That is, when Or o,a exceeds 96,
This is because even if O and Si are adjusted, cementite crystallizes and becomes brittle, which does not meet the purpose of the outer layer material. Note that a content of preferably 0.1% or more is effective.

Mo: Q, 6% or less 810 is effective in strengthening the base, but if the content is increased too much, the effect will be saturated and it will be uneconomical, and it will also have the effect of making the material hard and brittle, so 0. Must be 696 or less.

In addition, preferably l? A content of 0.1% or more is effective.

8n: 0.5% or less Depending on the casting conditions of the above-mentioned outer layer material, excessive ferrite may be present in the matrix, resulting in a decrease in yield strength and fatigue strength. In that case, 8, which has a pearlite stabilizing effect,
It is effective to add n within a range of 5% by weight at which its effect is saturated (). Note that it is effective to preferably contain 0.0396 or more.

Rare earth element: 0.1% or less If a rare earth element is added together with Mg and FA is added, the graphite becomes more spheroidized. At this time, the upper limit of the amount added is 0.1% by weight, at which the effect is saturated. Note that it is effective to preferably contain 0.02% or more.

Cu: 4.0% or less Cu, like Sn, has the effect of suppressing the precipitation of ferrite and stabilizing pearlite. It also improves corrosion resistance.

The outer side of the cylinder liner is generally water cooled.
Corrosion from the outside surface also causes liner failure (corrosion fatigue).

Therefore, if O is included, the accident resistance will be improved as above, but even if it exceeds 4.096, the effect will be saturated, so 4.
The upper limit is 0%. Note that a content of preferably 0.1% or more is effective.

Δl, Oa, Bm, Sr: It is known that inoculation is carried out with the total amount 18 of one or more types being 0.2% or less for the purpose of microstructuring and graphitization. As will be described later, the material quality of the liner of the present invention can also be improved by inoculation.

The inoculation effect reduces fading over time, so
For items that require a long time to solidify, such as thick-walled castings, ordinary Foci cannot be expected to have a significant inoculation effect. In that case, the sustainability of inoculation is improved by containing one or more of these elements. For this purpose, 1
The total amount of the species or two or more species may be 0.2% or less; if the content exceeds 0.2%, the effect will not be proportionally the same, and this will be disadvantageous in terms of cost. Note that a content of preferably 0.02% or more is effective.

(11) Inoculation of outer layer material Generally, inoculation is effective for refining the casting structure and promoting graphitization. If the inoculation technique is applied to the above-mentioned material, a material in which graphite is more finely and uniformly distributed can be obtained. At this time, the amount of melon 14 applied is suitably 0.05 to 1.0% in terms of lli.

In other words, if it is less than 0.05%, no inoculation effect can be expected, and -
This is because even if it exceeds 1.0%, a corresponding effect cannot be obtained. Ii'eSi is generally suitable as an inoculating agent, but 0a8i77 (,
Oa, 7n1%Ba, 8r21 tffl or 2
By using FeSi, which contains more than 100% seeds, a finer and more uniform slag texture with a more m-woven texture is produced. In addition, 81 after inoculation
The content is adjusted within the above-mentioned limited component range.

(2) Microscopic structure of outer layer material The microscopic structure of the above-mentioned spheroidal graphite cast iron material consists of spheroidal graphite and pearlite base. Shaohui's cementite may be crystallized in the tissue, but since cementite is brittle, it must be kept as low as possible for the purpose of non-inventiveness. The base is preferably burphite from the viewpoint of yield strength and fatigue strength, and it is best to use as little ferrite as possible. Note that even if bainite or martensitic gold precipitates, it may become brittle to some extent (it may gain the advantage of increased strength).However, bainite and martensitic gold precipitation In order to achieve this, it is necessary to take measures such as high alloying or special heat treatment, which is disadvantageous in terms of cost.

Next, the special cast iron material forming the inner layer of the composite cylinder liner of the present invention will be explained.

The present invention is characterized by using a material having the following composition as a liner inner layer material having excellent wear resistance and seizure resistance. That is, the inner layer has a weight i of 02.5 to 4.
0*, Si o, a ~ z, s%, Mn Q, 3 ~ j,
5%, PO, 05-1.5%, 5O13% 1ν lower,
Ni 2.54 or less, Or 1.54 or less, Moo, s
*Hereinafter, SnO, 54 or less, Cu4.0% or less, B, T
i, V, Nb, Zr (01 type or 2m or more total 1.0
% or less, AI! , Oa, Ba, Sr, a total of 0.241 or more of one or more rare earth elements, and the balance is Fe and normal impurities ρ).

Therefore, the chemical composition, microscopic structure, etc. of the upper specific material will be explained in detail below.

(1) Chemical composition 14-open BnGO, -56644 (5) C: 2.5 to 4.0% The inner layer material needs to have seizure resistance and wear resistance, and for that purpose, well-elongated graphite and carbide (Fe ,C.

(or double carbide, ① ash, etc.) are required. If it is less than 2.5%, both the amount of graphite and the amount of ash will be insufficient, and the seizure resistance and abrasion resistance will deteriorate. -If it exceeds 4.0%, both graphite and carbide will be too large and it will become brittle.

si: 0. B~2.5% 8i has graphitization ability and is an important element that determines the ratio between the amount of graphite and the amount of carbide. If it is less than 0.896, the amount of graphite will be insufficient and the seizure resistance will deteriorate. If it exceeds 2.5%, the amount of carbides will be small and the wear resistance will deteriorate.

M sword: 0.6-1.5% 81n is effective in removing the harm of S and strengthening the base. For this purpose, K is required to be 0.5% or more. -10,000
．． If it exceeds 5%, it becomes too hard and brittle.

P: 0.05-1.5% 17 PB It is generally known as an element that deteriorates the mechanical properties of materials, but in the liner inner layer material, by containing P, P eutectic is generated, P eutectic is an effective element in that it has a great effect on improving seizure resistance and wear resistance. In order to improve seizure resistance and wear resistance,
．． If it is less than 0.054, the effect cannot be expected, and it is 1.5%.
If it exceeds this, the mechanical properties will deteriorate, and chips will fall off, making it more likely that wear will occur.

8: 0.3% or less S is a so-called impurity element that deteriorates the mechanical properties of the material, but it is set to 0.5% or less as a problem-free range for the inner layer material of the present invention. Note that S is the most effective for excluding the influence of Mg in the outer layer. However, even in that case, 0
．． There is no need to exceed 5%.

Ni, Or, Mo, 8n Ni, Or, Mo, 8n is effective for strengthening the base, increasing toughness and hardnessF), Ni 2.59
6 or less, Orl, 54 or less, Mo (1,396 or less, S
By containing one or more types of 18 with n 0.596 or less, the abrasion resistance of the liner of the present invention can be improved.

The effects of each of these elements and reasons for limiting the components will be described below.

Ni H2, 5% or less Ni acts effectively to strengthen the base, but if it exceeds 2.5%, it is not only disadvantageous in terms of economic efficiency, but also weakens the hardened structure (bainite, martensite) and untransformed structure. This makes it more likely to occur, making it more brittle. In addition, seizure is likely to occur. Note that a content of 0.5% or more is effective.

Cjr: 1.5Φ or less Effective for strengthening the base like N1, but - 10,000 carbide generation trouble is strong. Therefore, if it exceeds 1.5%, the amount of graphite decreases, and the seizure resistance and toughness deteriorate. Incidentally, it is effective to preferably contain 0.1% or more.

Mo: 0.8% or less Like Ni, it is effective for strengthening bases, but horses! 9 If the content exceeds 0.8%, it will cause problems in terms of economics and hardening structure formation. Incidentally, the content is preferably 0.1% or more.

Sn: Q, 5% or less 8n has the effect of suppressing ferrite and stabilizing pearlite. However, this effect is 0.5% in the case of this material.
If it exceeds 0.5%, it will be saturated, so it should be 0.5% or less. Note that a content of preferably 0.05% or more is effective.

Ou: 4.0% or less Similar to Sn, Cu has the effect of suppressing ferrite and stabilizing pearlite, but it also has a large effect of improving corrosion resistance. Since corrosive wear is also a factor in wear on the inner surface of the liner, good results can be obtained by incorporating Ou in order to improve the wear resistance.

In that case, the upper limit is set at 4.0%, which saturates the corrosion resistance. Note that a content of preferably 0.1% or more is effective.

B, Ti, V, Nb, Zr: Type 1 1fc is 2 or more types, total 1.0% or less JP-A-Sho GO-36644 (6) Wear resistance! In order to improve the wear TGL, it is possible to almost achieve self-strength by producing P eutectic and cementite (iron carbide). It is effective to do so. For this purpose, HB, Ti, V, Nb, and Zr are suitable materials, all of which produce carbides as hard as cementite. However, since these are all strong deoxidizing agents, if they are contained in large amounts, they reduce the fluidity of the molten metal and tend to cause mold defects.

Therefore, it is set to 1.0% or less. In addition, preferably 0.0
A content of 2% or more is effective.

A/%Ca%Ba, Sr, rare earth elements: It is known that inoculation is carried out for the purpose of microstructural refinement and graphitization. As will be described later, the liner of the present invention can also be inoculated to improve the properties of many materials.

Since the original seed effect causes fading over time, 21 it is not expected that ordinary Fe8i will have much of an inoculation effect in thick-walled castings that require a long time to solidify. In that case, if one or more of these elements are included, the sustainability of the inoculation will be improved. For this purpose, the total amount of one or more types may be 0.2% or less; if the content exceeds 0.2%, the effect will not increase proportionally, which is disadvantageous in terms of cost. In addition, preferably 0.0
A content of 2% or more is effective.

(11) Inoculation of inner layer material In general, inoculation is effective for thinning the casting structure and promoting graphitization. If the inoculation technique is applied to the above material, a material in which graphite is evenly and finely distributed can be obtained. At this time, the amount of inoculation is 0.05 as Si content.
~1.0% is appropriate. That is, if it is less than 0.05%, no inoculation effect can be expected, and even if it exceeds -1.0%, a corresponding effect cannot be obtained. Generally, F is used as an inoculant.
e8i is preferred, but Cadi, Oa, kl, Ba, 8r may also be used to enhance the inoculation effect.

22 There is Fe8i which contains 111 or more kinds of rare earth elements, and by using it, a material with a fine and uniform structure can be obtained. Note that the Si content after the contact portion is adjusted within the above-mentioned limited component range.

(fil) Microscopic structure of inner layer material It consists of flaky graphite, carbide, P eutectic, and base.

The base is preferably pearlite, and since ferrite reduces wear resistance, it is best to use as little as possible. Also,
If bainite or martensite precipitates in the matrix, it will result in high hardness and wear resistance, but it will be more likely to cause seizure, so it is desirable to minimize it as much as possible.

The intermediate layer of the composite cylinder liner of the present invention will be briefly described.

As mentioned above, when a composite liner is cast with only two layers, the outer layer and the inner layer, there is a problem with the interlayer welds and the integrity of the inner layer material.
It is necessary to provide an intermediate layer and cast five layers. Furthermore, if the intermediate layer is divided into two or more layers (if the intermediate layer is folded into two layers, the total of the outer layer and inner layer will be 4 layers), the improvement in material quality will be even greater, but In actual production, this is disadvantageous in terms of cost.

The material of the intermediate layer will be described in detail later, but since the purpose is to make the inner layer material sound, it is desirable that it be as close to the inner layer material as possible.
0 bait. The reason for this is that the outer layer is melted when the middle layer is poured, and when the inner layer is poured, the casting thickness increases by 10 to 30 m, but when the inner layer is poured, the inner layer melts by 10 to 30 m. If it is less than that, there is little reason to provide an intermediate layer, and it will be the same as two-layer casting on the underground layer. Furthermore, if the power is less than 5 W, the amount of electric power poured into the mold is extremely small, and the casting itself becomes difficult. On the other hand, it is not necessary to exceed 50 mm, and due to the thickness of the liner (the maximum thickness is 80 mm on the sliding surface), the practical limit is 0 mm. It is not only the casting thickness at the time of casting, but also the thickness of the product.

Regarding the material of the intermediate layer, it is desirable that it be as close as possible to the inner layer material, but since it will be mixed with the outer layer material, one open 08G
Low 36644 (7) In reality, it cannot be made of the same material as the inner layer material.

The present invention is characterized in that the intermediate layer is made of a material having a chemical composition similar to that of a chip. That is, the middle layer is heavy i4, C2,0~4.0%, 8i0.8~5.0
*, Mn [1.4-1.2%, Po, 6% or less, 8
0.24 or less, Mg 0.05* or less; Ni2.54
Below, Cr0.8% or less, MOo, 64 or less, sno,
s96 or below, one piece or two of A110a, Ba, Sr [
It is a special cast iron material containing one or more of the following, with a total of 0.24 or more, with the balance being Fe, normal impurities, and unavoidably mixed elements from the outer layer.

Therefore, the chemical composition, microscopic structure, etc. of the above-mentioned specific material will be explained in detail below.

Medium Chemical component: 0: 2.0 to 4.0% If less than 2.0%, the graphitization of the material will be insufficient, causing problems in terms of heat conduction and toughness. - If it exceeds 4.096 million, there is too much graphite and it becomes brittle.

Si: 0.8 to 5.0 ft6 mm 25 If it is less than 0.8%, graphitization will be insufficient and problems with heat conduction and toughness will likely occur. If it exceeds 3.04, the ferrite content will be too large and the strength will be insufficient, and the slium dissolved into the ferrite will deteriorate the toughness.

Mn! 0.4~L2 *Kite combines with 8 to prevent the letter S, and also stabilizes the pearlite at the base and increases its strength. For this purpose, 0.4% or more is required, and if it exceeds L2*, it becomes brittle.

P: 0.6% or less P increases the fluidity of the molten metal, but produces P eutectic in the material, making the material brittle. This effect increases in proportion to the amount of P, but 0.0.
Must be 696 or less.

8: 0.2% or less S produces 8 compounds at grain boundaries, making the material brittle. Therefore, the content of the intermediate layer material should be 0.2% or less as long as it does not cause any actual damage.

Mg: 0.054 or less 26 Since the intermediate layer material does not require as much toughness as the outer layer material, it is not necessary to make the graphite spheroidal or pseudospherical. (Although the spheroidization and pseudo-spheroidization of graphite have the advantage of improving the toughness of the material.) Conversely, the intermediate layer material, which affects the inner layer material, partially melts into the inner layer material. ), graphite shape, segregation, etc. are likely to cause problems. Therefore, it is best not to contain Mg, but since Mg is contained in the outer layer,
Mg is inevitably contained in the intermediate layer.

From the above points, the range where there is no adverse effect of Mg is 0.0
5% or less.

N1, Or% Ha, 8n Ni% Or% 810.8 is effective for the same toughness, tooth 2.5% or less, Or o, s96 or less, MOo, 6
By containing one or more of 96 or less and 5% or less of SnO, the liner can be made tougher.

In addition, the above elements are contained for two reasons: when they are included before casting, and when they are not included before casting but are contained in the outer layer material and the next one melts in. .

Each action and outcome 27 The reason for the minute limit is explained below.

Ni: 2.5% or less Ni acts effectively on graphitization and strengthening the base, but 2.5% or less
If it exceeds 96, it is not only disadvantageous from an economic point of view, but also because hardened structures (bainite, martensite) and untransformed structures are not likely to occur and may even become brittle. Note that a content of 0.5% or more is effective.

Or: 0.8% or less Or acts to strengthen the base and stabilize cementite. In other words, exceeding aro, a96, 0%
This is because the adjustment of 8i also causes cementite to crystallize and become brittle, which meets the purpose of the outer layer material. still,
Preferably, a content of 0.1% or more is effective.

Mo: (3,696 or less Mo is effective in strengthening the base, but if its content is increased too much, the effect will become saturated and it will be uneconomical, and it will also harden the material.
The effect of making it brittle also appears, JP-A-1'1HGO, -56644
(8) In order to [1,696 or less]. Incidentally, the content is preferably 0.1% or more.

Sn: Q, 5% or less Depending on the casting conditions of the above outer layer material, an excessive amount of iC ferrite may be present in the matrix, resulting in a decrease in yield strength and fatigue strength. In that case, it is effective to add 8n, which has a stabilizing effect, within the range of 0.5% by coulance, at which its effect is saturated.Preferably, u0.03%.
The above content is effective.

Al, Oa, Ba, Sr: 11 fl' or the total of two or more types is 0.2% or less.

The reason for addition is the same as in the case of the outer layer, to prevent kneading (inoculation effect), and for this purpose, one or more upper width elements are added in a total amount of 0.2% or less. I do. This is because if the content is more than that, the effect will not be proportionally the same and it will be disadvantageous in terms of cost. In addition, Koushikake 0.0
A content of 2% or more is effective. By the way, even if the above-mentioned elements are not contained before decay, they also include cases where they are necessarily thermally melted into the outer layer.

Others: Although there is little or no need to include elements in the intermediate layer material, there are elements that are inevitably included because they were included in the outer layer material. For example, Ou is a rare earth element. Although it varies depending on the intermediate layer casting thickness and casting conditions, 30 to 70% of the outer layer content (expressed as weight %) is concentrated in each layer even if the intermediate layer material does not contain any content before casting. necessarily included.

(11) Inoculation of intermediate material Generally, inoculation is effective for refining the casting structure and promoting graphitization. If the inoculation technique is applied to the above material, a material in which graphite is finely and uniformly distributed can be obtained. At this time, the inoculation amount is 0.05 to 1 as Si content.
．． 0% is appropriate. That is, if it is less than 0.054, no inoculation effect can be expected, and even if it exceeds -1.0%, a corresponding effect cannot be obtained. Generally, FeS is used as an inoculant.
80 is preferable, but 0n8i17y, Oa, A/, Ba, Sr
There is FeSi that contains one or more types of .By using this material, a material with a fine and uniform structure can be obtained.

Note that the 81-containing phosphorus after inoculation is adjusted to the above-mentioned limited component range.

all) Microscopic structure of the intermediate layer material As mentioned above, the purpose of providing the intermediate layer is to improve welding and to prevent the inner layer material from being affected by the outer layer.Therefore, less emphasis is placed on strength. Although it is not necessary to do so, it becomes a problem if it becomes too brittle. From the above points, ideally it is desirable to consist of only graphite and a base. However, in reality, cementite may crystallize, but if it is below the limit amount (15% or less in terms of area ratio), there will be no problem, and the base may be pearlite or 1 yufuetzite (including a mixture of both). desirable. bainite,
Martensite makes the material brittle, so it should be suppressed as much as possible.

As described above, the present invention consists of an outer layer material, an intermediate layer material, and an inner layer material having a specific chemical composition, and is further subjected to heat treatment as described below.

That is, the centrifugally cast composite cylinder liner is annealed at a temperature below the austenite range for the purpose of stabilizing the structure and relieving strain.

Usually the temperature for this purpose is 400-650°C.

Compared to this strain relief annealing, it is disadvantageous in terms of cost, but it improves the toughness of the material, increases the hardness of the base structure, and
In terms of uniformity of the matrix structure, it is possible to improve the material quality by performing heat treatment at a temperature in the austenite region. The temperature range varies depending on whether the objective is toughness or high hardness, but generally 800 to 1000°C is appropriate. After the temperature is maintained in this range, it is necessary to increase the cooling rate (inner diameter 7
Even with the 4000 large cylinder finisher, some parts are 20
(possible up to 00℃/■r). After heat treatment at a temperature in the austenite range, strain relief annealing at 400 to 650°C is usually added.

Next, examples of the present invention will be described.

<Example> JP-A-36644(9) Composite cylinder liner' (i-manufactured) with first facestones 1, &2, and 3 under Ht forming conditions such as chipping.

O fishing 1 thread mold inner diameter: 6400 0 Mold making method 2 Horizontal centrifugal cup making o (] A: 6400 (] A120GO face thickness: Outer layer 70U+ Middle layer 25 ts 1fuq/ll etc.S5+u O chemical structure : Shown in Table 1 (Positive %, remaining Fe and impurities) 0 Hardness distribution (■u) : O Mechanical properties shown in Figure 2 Mechanical properties include tensile strength of 18-25 Kg/
mJ, elongation is in the range of 0.2 to 0.8%.

O microscope Mi fiber 1 to black 6 cylinder cylinder, inner diameter is 5600 (outer layer material) and 5000 inner layer material)
Regarding the microscopic structure in the 460〆 (inner layer material) part, high 1 is shown in Figure 5 (■, ILC outside R)
, Fig. 4 I, ■ (middle layer) and Fig. 5 1, ■ (inner layer), A2 in Fig. 6 ■, ■ (outer layer), Fig. 7 ■, ■ [middle layer], and Fig. 8 I , II (inner layer). However, I has a magnification of 50, and ■ has a magnification of 400.

Product 0: This cast product was cut to obtain a cylinder liner with an outer diameter of 600 da and an inner diameter of 440 y.

(Chipped leaf), A 85 Table 2 Mechanical properties (Tensile test) Inner layer: Me 460 Outer layer: 0560 As described above, the composite cylinder twiner of the present invention has excellent toughness, especially since it is the starting point of fracture. The outer layer of the liner, which requires
7 specific chemical compositions with excellent seizure resistance and abrasion resistance,
It is made of a special cast iron material, and the middle layer is made of a special cast iron material with a specific chemical composition for improving the welds between each layer and making the inner layer material sound, so that the outer layer and the middle layer, the middle layer and the inner layer,
6 B6 are formed by metallurgically integrating the fused metals, so the rlIff welds of each layer are improved, the inner layer material is also sounder, and the inner surface of the liner has increased strength without impairing its original usage characteristics. can be measured.

The composite cylinder liner according to the present invention can be easily produced with desired characteristics by using the centrifugal casting method, and there is no problem with the welding between the layers.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing a structural example of a composite cylinder twiner according to the present invention, and Fig. 2 is a hardness distribution graph of the embodiment, where the horizontal axis shows the distance from the inner surface and the vertical axis shows the hardness. It is something. Figure 6 1. [I to FIG. 11] are micrographs of examples of the composite cylinder liner of the present invention, and FIG. 6, ■, FIG. 6, ■, and FIG. I, ■, 7th drawing, I [and 10th
1JI, l! -m middle layer structure, Figure 5, ■, 8th
Figures I, 1 and 11, I, ■ show the inner layer tissue, respectively. (a), ..., outer layer, 0) Kawauchi layer, ((+)...middle layer. Procedural amendment (method) 1 Indication of J+ items 1982 Patent Application No. 145499 C32, Name of the invention Conflict Cylinder liner 3 Relationship with sleeve 11 - name and j mark - Patent applicant (105) Kubota Iron Works Co., Ltd. 4 Agent 577 Illv 4 Brief description of the drawing of Soso Column 7 Contents of amendment

Claims (1)

[Claims] 1. In weight%, 0: 2.6-4.0%) 3i: L5-3.5% 5(n: 0.2-1.096 P: 0.5% or less S : 0.04% or less Mg: 0.02-0.1% Ni: 2.5% or less Or: 0.84 or less Mo: 0.6i or less Sn: 0.396 or less Rare earth elements: 0.1% Contains one or more of the following Ou: 4.0% or less A/, one or more of Oa, Ba, and Sr: 0.296 or less g, with the remainder being Fe and normal impurities. The outer layer is made of spheroidal graphite cast iron material mainly composed of spheroidal graphite and pearlite base, and the weight is 1%, 0: 2.0-4.04 Si: 0.8-5.0% Mn: 0.4- L2% PtO, 696 or less 8: 0.2% or less Mg: 0.05% or less, Ni: 2.5i or less CR: o, 8% or less boo! 0.6% or less Sn: 0.3% or less AI !, (one or more of 3a, Ba, Sr) Total: 0.2% or less ○ Contains one or more of these, the remainder being substantial Fe and normal impurities and unavoidable A8 from the outer layer Intermediate layer consisting of contaminants and η, in weight%: 0:2.5~4.0% 8i; 0.B~2.5% Mn: 0.3~1.596 P: 0°05 ~1.54 8: 0.3i or less, Ni: 2.5% or less Or: L 5% or less Mo: Q, 8% or less Sn: 0.5% or less Ou: 4.0% or less B, Ti, ■ , Nb, Zr, total of one or more types: 1.04 or less A/, Oa%Ba%8r, one or more rare earth elements = one or two of the following: 0.2% or less The outer layer and the intermediate layer, and the intermediate layer and the inner layer are each formed by metallurgy 7N '560-36644 (2
) A composite cylinder finisher characterized by being integrated with melting.