JP2018104744A - Cast iron, manufacturing method of cast iron and cylinder block - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide cast iron achieving both of high abrasion resistance and castability.SOLUTION: There is provided cast iron containing, by mass%, C:3.0 to 3.8%, Si:1.0 to 3.0%, Mn:0.6 to 1.0%, Cr:over 0 and 0.6% or less, Mo:0.03 to 0.4%, Cu:0.6 to 1.6% and the balance Fe with inevitable impurities.SELECTED DRAWING: Figure 4

Description

  The present invention relates to cast iron having both high wear resistance and castability and a method for producing the same. The present invention also relates to a cylinder block including the cast iron.

  A cylinder block which is one of the members constituting the internal combustion engine includes a mechanism for sliding the cylinder by the explosion of fuel, and the material constituting the mechanism is required to have wear resistance. This is because, when the wear resistance of the material is low, there is a possibility that piston seizure, deterioration of airtightness, etc. may occur. Furthermore, in order to further increase the output of the internal combustion engine, it is necessary to increase the wear resistance of the material.

  For this reason, cast iron, which is a material having high wear resistance, is widely used for cylinder blocks. Further, cast iron having higher wear resistance and advantageous physical properties other than wear resistance has been developed.

  For example, in Patent Document 1, C: 3.2 to 3.6% by weight, Si: 1.7 to 2.4% by weight, Mn: 0.45 to 0.9% by weight, P: 0.2% by weight Hereinafter, S: 0.2 wt% or less, Cr: 0.2-0.5 wt%, Cu: 0.3-0.5 wt%, Mo: 0.2-0.4 wt%, A cast iron having a CE value of 3.8 to 3.95 is disclosed.

  In Patent Document 2, C: 2.9 to 3.6 mass%, Si: 2.0 to 2.5 mass%, Mn: 0.5 to 1.0 mass%, P: 0.03 to 0.3 mass% Mass%, S: 0.01-0.13 mass%, Cu: 0.03-0.6 mass%, Cr: 0.03-0.3 mass%, Sn 0.001-0.3 mass% and / or Or, Sb: 0.001 to 0.2% by mass, and the balance is disclosed as cast iron containing A-type graphite composed of iron and inevitable impurities.

  In Patent Document 3, by weight, C: 3.2 to 3.49%, Si: 1.8 to 2.2%, S: less than 0.15%, P: less than 0.15%, Mn: 0.00. 3 to 0.8%, Cr: 0.2 to 0.4%, Mo: 0.1 to 0.4%, V: 0.03 to 0.3%, Cu: 0.3 to 1.0% Nb: less than 0.15% and others: substantially pearlite gray cast iron alloy containing iron and impurities.

JP 2003-253375 A (published September 10, 2003) JP 2008-106357 A (published May 8, 2008) JP 2005-525468 Gazette (released August 25, 2005)

  However, the conventional techniques as described above leave room for improvement from the viewpoint of achieving both wear resistance and castability.

  An object of one embodiment of the present invention is to provide cast iron that achieves both high wear resistance and castability.

  As a result of intensive studies to achieve the above object, the present inventors have found that the above problem can be solved by making the Cu content higher than usual. Based on the above findings, the present inventors have completed the present invention. That is, the present invention includes the following inventions.

  <1> By mass%, C: 3.0 to 3.8%, Si: 1.0 to 3.0%, Mn: 0.6 to 1.0%, Cr: more than 0 to 0.6% Hereinafter, Cu: 0.6 to 1.6%, Mo: 0.01 to 0.4% and / or W: 0.02 to 0.8%, balance: Fe and unavoidable impurities Cast iron.

  <2>% by mass, C: 3.3 to 3.5%, Si: 1.7 to 2.3%, Mn: 0.7 to 0.8%, Cr: 0.2 to 0.4% Cu: 0.9-1.1%, Mo: 0.1-0.2% and / or W: 0.2-0.4%, balance: Fe and unavoidable impurities, Cast iron.

<3> The cast iron according to <1> or <2>, wherein a Σ value represented by the following formula (1) is 2.45 or less.
Σ value = [Mn] + [Cr] + [Cu] + [Ni] + [Mo] + [W] (1)
(In the formula, [] represents the content (% by mass) of the element in parentheses).

<4> The cast iron according to any one of <1> to <3>, wherein a carbon equivalent represented by the following formula (2) is 3.8 to 4.15.
Carbon equivalent = [C] +0.31 [Si] −0.027 [Mn] +0.33 [P] +0.4 [S] −0.063 [Cr] +0.074 [Cu] −0.015 [Mo ] -0.020 [W] (2)
(In the formula, [] represents the content (% by mass) of the element in parentheses).

  <5> A cylinder block comprising the cast iron according to any one of <1> to <4>.

  <6>% by mass, C: 3.0 to 3.8%, Si: 1.0 to 3.0%, Mn: 0.6 to 1.0%, Cr: more than 0 to 0.6% Hereinafter, Cu: 0.6 to 1.6%, Mo: 0.01 to 0.4% and / or W: 0.02 to 0.8%, balance: Fe and unavoidable impurities. A method for producing cast iron, comprising preparing a molten metal and casting the molten metal into a mold by a gravity casting method or a centrifugal casting method.

  According to one aspect of the present invention, cast iron having both wear resistance and castability is provided.

(A) is the schematic showing the method of the hot water flow test performed in Example 1. FIG. A runway through which the molten metal flows is provided at one end of each of the test pieces 1 to 3 made of cast iron. (B) is the schematic showing the method of the abrasion test performed in Example 2. FIG. (A)-(e) is a result of the hot water flow property test of the test piece produced in the Example. (A)-(c) is a metallographic microscope image which observed the structure | tissue of the test piece produced in the Example. It is a graph showing the result of the abrasion resistance test performed with respect to invention material and FC material.

  Hereinafter, although an example of embodiment of this invention is demonstrated in detail, this invention is not limited to this. Unless otherwise specified in the present specification, “A to B” representing a numerical range means “A or more and B or less”, and when simply expressed as “%”, it means mass%.

[1. Physical properties of cast iron
Hereinafter, physical properties, that is, wear resistance and castability, which are characteristics of cast iron according to an embodiment of the present invention, will be described.

[1-1. Abrasion resistance]
The wear resistance of cast iron according to an embodiment of the present invention can be evaluated by, for example, the method in Example 2. In order to obtain higher wear resistance than conventional materials, the wear amount of the cast iron when evaluated by the above method is preferably 0.80 μm or less.

  As a simpler method for evaluating the wear resistance of a material, there is a method for evaluating the Brinell hardness, tensile strength, and elastic modulus of the material.

  In this specification, the Brinell hardness of the material is determined by, for example, a method in which a cemented carbide ball having a diameter of 10 mm is pushed into the material with a load of 29,400 N, and the load is divided by the surface area of the depression generated at that time. It can be measured. When measured by the above method, the Brinell hardness of the cast iron according to an embodiment of the present invention is preferably 205 HB or more, and more preferably 220 HB or more, from the viewpoint that high abrasion resistance as described above can be expected. On the other hand, from the viewpoint of not reducing the workability of the cast iron, the Brinell hardness of the cast iron is preferably 255 HB or less, and more preferably 250 HB or less.

  In this specification, the tensile strength of a material can be measured by a metal material tensile test, for example. When measured by the above method, the tensile strength of the cast iron is preferably 240 MPa or more from the viewpoint of ensuring the strength of the product obtained by processing the cast iron according to one embodiment of the present invention.

  In this specification, the elastic modulus of a material can be measured by a metal material tensile test, for example. When measured by the above method, the elastic modulus of the cast iron according to the embodiment of the present invention is preferably 80 GPa or more from the viewpoint of ensuring the rigidity of the product obtained by processing the cast iron according to the embodiment of the present invention.

[1-2. Castability]
As an index of castability, for example, hot water flowability can be employed. In the present specification, “hot water flowability” intends the flowability of molten metal. The hot water flowability can be evaluated, for example, by the method performed in Example 1 (see FIG. 1). According to the above method, the fact that the hot water poor portion occurring in the cast iron test pieces 1 to 3 is small, in particular, the small hot water poor portion occurring in the test piece 3 means that the hot water flowability is high. .

  The cast iron according to an embodiment of the present invention can have both the above-described wear resistance and castability at suitable values by having a specific composition described in detail below. Cast iron having such physical properties can withstand abrasion due to sliding and can be cast into a complicated shape, and thus is suitable as a material for a cylinder block, for example.

[2. cast iron〕
[2-1. Alloy components of cast iron]
Hereinafter, the composition of cast iron according to an embodiment of the present invention will be described in detail for each element.

(carbon)
The carbon contained in the cast iron according to an embodiment of the present invention is preferably 3.8% by mass or less, and more preferably 3.5% by mass or less. When the carbon content exceeds 3.8% by mass, excessive crystallization amount of graphite and excessive growth of crystallized graphite occur, and the strength of the cast iron decreases.

  3.0 mass% or more is preferable, as for carbon which the cast iron which concerns on one Embodiment of this invention contains, 3.1 mass% or more is more preferable, and 3.3 mass% or more is further more preferable. When the carbon content is less than 3.0% by mass, excessive reduction of the crystallization amount of graphite and excessive refinement of the crystallized graphite occur, and the castability of the cast iron decreases.

(Silicon)
The silicon contained in the cast iron according to one embodiment of the present invention is preferably 3.0% by mass or less, and more preferably 2.3% by mass or less. When the silicon content exceeds 3.0% by mass, excessive crystallization amount of graphite and excessive growth of crystallized graphite occur, and the strength of the cast iron decreases.

  1.0 mass% or more is preferable, as for the silicon which the cast iron which concerns on one Embodiment of this invention contains, 1.5 mass% or more is more preferable, and 1.7 mass% or more is further more preferable. When the silicon content is less than 1.0% by mass, excessive reduction of the crystallization amount of graphite and excessive refinement of the crystallized graphite occur, and the castability of the cast iron is lowered.

(manganese)
The manganese contained in the cast iron according to an embodiment of the present invention is preferably 1.0% by mass or less, and more preferably 0.8% by mass or less. When the manganese content exceeds 1.0 mass%, the pearlite of the base structure becomes excessively dense, and when the thickness of the cast product is 5 mm or less, the base structure may be transformed into martensite or bainite. . Since martensite and bainite are both hard structures, the workability of the cast iron is reduced.

  The manganese contained in the cast iron according to an embodiment of the present invention is preferably 0.6% by mass or more, and more preferably 0.7% by mass or more. When the manganese content is less than 0.6% by mass, the pearlite of the cast iron base structure becomes coarse and the hardness decreases.

(chromium)
The chromium contained in the cast iron according to an embodiment of the present invention is preferably 0.6% by mass or less, and more preferably 0.4% by mass or less. When the chromium content exceeds 0.6% by mass, a carbide is formed between chromium and carbon, and the workability of the cast iron is lowered.

  The chromium contained in the cast iron according to an embodiment of the present invention preferably exceeds 0% by mass, more preferably 0.1% by mass or more, and further preferably 0.2% by mass or more. When chromium is not contained, the hardness of the cast iron matrix structure is lowered.

(copper)
1.6 mass% or less is preferable and, as for the copper which the cast iron which concerns on one Embodiment of this invention contains, 1.1 mass% or less is more preferable. When the copper content exceeds 1.6% by mass, the total content of copper and molybdenum becomes high, and the cast iron base structure is transformed into martensite or bainite, so that the workability of the cast iron is lowered.

  The copper contained in the cast iron according to an embodiment of the present invention is preferably 0.6% by mass or more, more preferably 0.7% by mass or more, and further preferably 0.9% by mass or more. When the copper content is less than 0.6% by mass, the castability of the cast iron is lowered, the pearlite of the base structure is coarsened, and the hardness is further lowered.

(molybdenum)
The molybdenum contained in the cast iron according to an embodiment of the present invention is preferably 0.4% by mass or less, more preferably 0.35% by mass or less, and further preferably 0.2% by mass or less. When the molybdenum content exceeds 0.4% by mass, the hardness of the matrix structure becomes excessive, and carbides are formed between molybdenum and carbon. As a result, the workability of the cast iron is reduced. Further, when the total content of copper and molybdenum is increased, the base structure is transformed into martensite or bainite, so that the workability of the cast iron is also lowered in this case.

  The molybdenum contained in the cast iron according to one embodiment of the present invention is preferably 0.01% by mass or more, and more preferably 0.1% by mass or more. When the molybdenum content is less than 0.01% by mass, the hardness of the cast iron matrix structure is lowered, and pearlite at high temperatures becomes unstable.

(tungsten)
0.8 mass% or less is preferable, as for the tungsten which the cast iron which concerns on one Embodiment of this invention contains, 0.7 mass% or less is more preferable, and 0.4 mass% or less is further more preferable. When the tungsten content exceeds 0.8 mass%, the hardness of the matrix structure becomes excessive, and carbides are formed between tungsten and carbon. As a result, the workability of the cast iron is reduced. Moreover, since the base structure transforms into martensite or bainite when the total content of copper and tungsten is high, the workability of the cast iron is also lowered in this case.

  0.02 mass% or more is preferable and, as for the tungsten which the cast iron which concerns on one Embodiment of this invention contains, 0.2 mass% or more is more preferable. When the tungsten content is less than 0.02% by mass, the hardness of the cast iron matrix structure is lowered, and pearlite at high temperatures becomes unstable.

(Relationship between molybdenum and tungsten)
In the cast iron according to one embodiment of the present invention, both molybdenum and tungsten have the same effect of hardening the cast iron. Therefore, molybdenum and tungsten are mutually replaceable components. The cast iron may contain molybdenum and may not contain tungsten, may not contain molybdenum, may contain tungsten, and may contain molybdenum and tungsten.

  In order to obtain the same effect as containing molybdenum by including tungsten, the content of tungsten may be set to twice the content of molybdenum ([Mo] = 2 [W]). This relationship is considered to be caused by a difference in atomic weight between molybdenum and tungsten.

[2-2. Inevitable impurities]
The cast iron according to one embodiment of the present invention contains inevitable impurities. The unavoidable impurities can include the elements described below. Here, the inevitable impurities are components derived from cast iron raw materials, facilities for producing cast iron, etc., and are not intentionally added, but mean components that are inevitably mixed in cast iron. To do.

(Rin)
0.08 mass% or less is preferable and, as for the phosphorus which the cast iron which concerns on one Embodiment of this invention contains, 0.05 mass% or less is more preferable. By setting the phosphorus content to 0.08% by mass or less, the strength of the cast iron can be maintained in a suitable range.

(sulfur)
0.2 mass% or less is preferable and, as for sulfur which the cast iron which concerns on one Embodiment of this invention contains, 0.15 mass% or less is more preferable. By setting the sulfur content to 0.2% by mass or less, hot cracking of the cast iron in the casting solidification process can be prevented.

(nickel)
0.05 mass% or less is preferable and, as for nickel which the cast iron which concerns on one Embodiment of this invention contains, 0.02 mass% or less is more preferable.

(aluminum)
0.05 mass% or less is preferable and, as for the aluminum which the cast iron which concerns on one Embodiment of this invention contains, 0.01 mass% or less is more preferable. By setting the aluminum content to 0.05 mass% or less, the formation of pinholes that are casting defects can be suppressed.

(titanium)
The titanium contained in the cast iron according to an embodiment of the present invention is preferably 0.05% by mass or less, and more preferably 0.01% by mass or less. By making the titanium content 0.05% by mass or less, it is possible to suppress a decrease in workability due to generation of titanium carbide.

(vanadium)
The vanadium contained in the cast iron according to an embodiment of the present invention is preferably 0.01% by mass or less, and more preferably 0.005% by mass or less. By setting the vanadium content to 0.01% by mass or less, it is possible to suppress a decrease in workability due to the generation of vanadium carbide.

[2-3. Parameters between components]
(Σ value)
The cast iron according to one embodiment of the present invention preferably has a Σ value represented by the following formula (1) of 2.45 or less. When the Σ value is 2.45 or less, excessive hardening of the cast iron due to transformation of the base structure of the cast iron into martensite or bainite can be prevented. That is, when the Σ value is 2.45 or less, the workability of the cast iron falls within a suitable range.
Σ value = [Mn] + [Cr] + [Cu] + [Ni] + [Mo] + [W] (1)
(In the formula, [] represents the content (% by mass) of the element in parentheses).

(Carbon equivalent (CE value))
In the cast iron according to an embodiment of the present invention, the carbon equivalent represented by the following formula (2) is preferably 4.15 or less, and more preferably 4.1 or less. In the cast iron according to one embodiment of the present invention, the carbon equivalent represented by the following formula (2) is preferably 3.8 or more, and more preferably 3.9 or more. When the carbon equivalent is in the above range, it is possible to achieve both the wear resistance and the fluidity of the cast iron.
Carbon equivalent = [C] +0.31 [Si] −0.027 [Mn] +0.33 [P] +0.4 [S] −0.063 [Cr] +0.074 [Cu] −0.015 [Mo ] -0.020 [W] (2)
(In the formula, [] represents the content (% by mass) of the element in parentheses).

[2-4. Cast iron structure]
The cast iron base structure according to the embodiment of the present invention is not particularly limited. When the cast iron is processed into a cylinder block, pearlite is preferably the main base structure. However, for example, when processing into a member (for example, a bearing) requiring higher hardness, the cast iron may be heat-treated to transform the base structure into martensite and / or bainite. Moreover, the said heat processing may be given only to a part of said cast iron.

  The shape of graphite in the structure of cast iron according to an embodiment of the present invention is not particularly limited. When processing the cast iron into a cylinder block, the shape of the graphite is preferably A-type graphite.

[3. Casting method)
The cast iron casting method according to one embodiment of the present invention is not particularly limited. Below, an example of the casting method of the said cast iron is illustrated.

  First, the same composition as cast iron according to an embodiment of the present invention (that is, C: 3.0 to 3.8% by mass, Si: 1.0 to 3.0% by mass, Mn: 0.6 to 1.0) Mol%, Cr: more than 0 and 0.6 mass% or less, Mo: 0.01-0.4 mass%, Cu: 0.6-1.6 mass%, balance: Fe and inevitable impurities) To prepare. The method for preparing the molten metal and the order of adding the various components to the molten metal are not particularly limited, and known methods can be used. In addition, the composition of the molten metal is calculated from the ratio of the added raw material when the molten metal is prepared.

  Next, the prepared molten metal is cast into a mold. At this time, either a gravity casting method or a centrifugal casting method may be employed. When manufacturing a cylinder block by casting, it is preferable to employ a gravity casting method. The part that has been cast may be used as it is taken out from the mold, or a part or all of the part may be heat-treated.

[4. (Use of cast iron)
The application of the cast iron according to one embodiment of the present invention is not particularly limited. Considering that the cast iron achieves both castability and high wear resistance, it is preferable to use the cast iron for the cylinder block. In particular, it is more preferable to use the cast iron for a member exposed to a high combustion pressure in a cylinder block, that is, a cylinder head or the like.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

[Example 1]
Cast iron pieces with different compositions were prepared and various physical properties were investigated.

  Prepare a molten metal having the component composition shown in Table 1, and test pieces made of the inventive materials 1 to 10, the comparative materials 1 to 5, and the FC material by gravity casting (all 4 cm long × 20 cm wide × 5 mm thick). Was cast. A furan mold was used as the mold. In addition, the component composition of each material is a value measured by analyzing the said material after casting by emission spectral analysis.

  In the table, flake graphite cast iron (FC) having a general level of wear resistance and castability is shown as an FC material. Inventive materials 1 to 10 have a common feature that the Cu content is higher than that of the FC material.

[1-1. Measurement of Brinell hardness]
The Brinell hardness of the produced test piece was measured under the following conditions. The measurement results are shown in Table 1.
・ Used ball: Cemented carbide class ・ Ball diameter: 10mm
・ Load: 29,400N
[1-2. Measurement of tensile strength]
The tensile strength of the produced test piece was measured with a hydraulic universal testing machine (manufactured by Shimadzu Corporation). The measurement was performed twice and the arithmetic average of the two measurements was taken as the tensile strength. The measurement results are shown in Table 1.

[1-3. Measurement of elastic modulus]
The elastic modulus of the produced test piece was measured with a hydraulic universal testing machine (manufactured by Shimadzu Corporation). The measurement was performed twice, and the arithmetic average of the two measurements was taken as the elastic modulus. The measurement results are shown in Table 1.

(Measurement results of physical properties related to wear resistance)
Inventive materials 1 to 5 are mass%, C: 3.3 to 3.5%, Si: 1.7 to 2.3%, Mn: 0.7 to 0.8%, Cr: 0.2 to Cast iron comprising 0.4%, Cu: 0.9-1.1%, Mo: 0.1-0.2% and / or W: 0.2-0.4%, balance: Fe and unavoidable impurities It is. That is, it has a composition that is particularly suitable for achieving the object of one embodiment of the present invention.

  Invention materials 6 to 10 are: C: 3.0 to 3.8%, Si: 1.0 to 3.0%, Mn: 0.6 to 1.0%, Cr: more than 0 to 0.6% Hereafter, it is cast iron which consists of Cu: 0.6-1.6%, Mo: 0.01-0.4% and / or W: 0.02-0.8%, remainder: Fe and an unavoidable impurity. That is, the composition has a composition suitable for achieving the object of one embodiment of the present invention.

  The physical properties of the inventive materials 1 to 10 shown in Table 1 are as follows. In all the inventive materials, the Brinell hardness was within a particularly preferable range of 220 to 250 HB. In all the inventive materials, the tensile strength was 240 MPa or more, which is a preferable range. In all the inventive materials, the elastic modulus was 80 GPa or more which is a preferable range.

  On the other hand, the comparative materials 1-5 have compositions outside the above range. Specifically, it is different from the inventive material in the following points, and as a result, defects in physical properties occurred.

  Since the comparative material 1 has an excessive molybdenum content, the Brinell hardness becomes too high and the workability is low.

  Although the comparative material 2 has a high molybdenum content, but the carbon equivalent is too large, the tensile strength and the elastic modulus are low.

  The comparative material 3 has a large Σ value, the base structure is transformed, and the Brinell hardness is too large.

  Since the comparative material 4 has a low carbon content and the carbon equivalent is too small, the graphite crystallization amount is insufficient and the Brinell hardness is too large.

  The comparative material 5 does not contain molybdenum, and the tensile strength is out of the preferred range.

[1-4. Hot water flow]
The hot water flow properties of the inventive materials 1, 3, and 10, the comparative material 5, and the FC material were measured. Hereinafter, the measurement method will be described with reference to FIG.

  Three test pieces 1 to 3 were arranged at intervals of 3 cm, and a groove through which the molten metal could flow was provided at one end of the test pieces 1 to 3. Test pieces 1 to 3 were produced by the same method as 1-1 to 1-3, and the size was 4 cm long × 20 cm wide × 5 mm thick. Next, 1400 ° C. molten metal was poured into the groove.

(result)
The results of the above test are shown in FIG. The hot water run-off portion that occurred in Invention Materials 1 and 3 was approximately the same size as the hot run-out portion that occurred in the FC material ((a) and (b) of FIG. 2). For this reason, it can be said that the inventive materials 1, 3 and 10 have a hot water flow property equivalent to that of the FC material, and thus have castability equivalent to that of the FC material. The hot water poor portion generated in the inventive material 10 was slightly larger than the hot water poor portion generated in the FC material ((c) of FIG. 2). For this reason, it can be said that the inventive material 10 has a hot water flow property slightly inferior to that of the FC material, and therefore has a castability slightly inferior to that of the FC material.

  On the other hand, the hot water runoff portion that occurred in the comparative material 5 was much larger than the hot runout failure portion that occurred in the FC material ((d) in FIG. 2). For this reason, it can be said that the comparative material 5 has a hot water flow property that is clearly inferior to that of the FC material, and therefore has a castability that is clearly inferior to that of the FC material.

[1-5. Organizational structure]
The base structures of the inventive materials 1 and 3 and the comparative material 3 were observed with a metallographic microscope.

(result)
Inventive materials 1 and 3 have a pearlite base, whereas comparative material 3 has a high Σ value (particularly, an excessive Mo content), so that the base structure is transformed into bainite (FIG. 3). (C)). For this reason, the hardness as a material becomes excessive, and the workability deteriorates.

[Example 2]
A wear test was performed using the inventive material 1 and the FC material.

  First, the inventive material 1 and the FC material were cast into a plate shape by the same method as in Example 1 (cylinder block material 4). Furthermore, a wear test was imposed under the conditions shown in Table 2 below using a metal piece (counter material 5) cut out from a piston ring material actually used as the counterpart material. A schematic diagram of the test is shown in FIG.

  The test results are shown in FIG. The wear amount of the inventive material 1 is reduced by 20% or more compared to the wear amount of the FC material. That is, the wear resistance of the inventive material 1 was much higher than that of the FC material.

  The cast iron according to an embodiment of the present invention is suitable as, for example, a material for a cylinder block because it can sufficiently withstand abrasion due to sliding and can be cast into a complicated shape.

1 Test piece 2 Test piece 3 Test piece 4 Cylinder block material 5 Counterpart material

Claims (6)

% By mass
C: 3.0 to 3.8%,
Si: 1.0-3.0%,
Mn: 0.6 to 1.0%
Cr: more than 0 and 0.6% or less,
Cu: 0.6 to 1.6%,
Mo: 0.01-0.4% and / or W: 0.02-0.8%,
Balance: Fe and inevitable impurities,
Cast iron characterized by comprising. % By mass
C: 3.3 to 3.5%,
Si: 1.7-2.3%,
Mn: 0.7 to 0.8%
Cr: 0.2 to 0.4%,
Cu: 0.9 to 1.1%,
Mo: 0.1-0.2% and / or W: 0.2-0.4%
Balance: Fe and inevitable impurities,
Cast iron characterized by comprising. The cast iron according to claim 1, wherein a Σ value represented by the following formula (1) is 2.45 or less.
Σ value = [Mn] + [Cr] + [Cu] + [Ni] + [Mo] + [W] (1)
(In the formula, [] represents the content (% by mass) of the element in parentheses) The cast iron according to any one of claims 1 to 3, wherein a carbon equivalent represented by the following formula (2) is 3.8 to 4.15.
Carbon equivalent = [C] +0.31 [Si] −0.027 [Mn] +0.33 [P] +0.4 [S] −0.063 [Cr] +0.074 [Cu] −0.015 [Mo ] -0.020 [W] (2)
(In the formula, [] represents the content (% by mass) of the element in parentheses)   A cylinder block comprising the cast iron according to any one of claims 1 to 4. % By mass
C: 3.0 to 3.8%,
Si: 1.0-3.0%,
Mn: 0.6 to 1.0%
Cr: more than 0 and 0.6% or less,
Cu: 0.6 to 1.6%,
Mo: 0.01-0.4% and / or W: 0.02-0.8%,
Balance: Fe and inevitable impurities,
A method for producing cast iron, comprising preparing a molten metal having a composition comprising: and casting the molten metal into a mold by a gravity casting method or a centrifugal casting method.