JP2004360031A - Composite cast iron member, and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite cast iron member in which a nonferrous metal material can be stacked at a high strength by using carbon-containing cast iron, and to provide its production method. <P>SOLUTION: The composite cast iron member consists of: a carbon-containing cylinder block body 12; a decarburized layer 12a formed on the surface of the cylinder block body 12a; and a nonferrous metal material layer 14 integrally stacked to the decarburized layer 12a in a joined state. The nonferrous metal material layer 14 may be made of a copper alloy, an aluminum alloy or the like. In the decarburization treatment, the surface of a cylinder tube 13 in the cylinder block body 12 is stacked with iron sand 15, heating is performed to a high temperature, and carbon in the cylinder block body 12 is oxidized and removed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a composite metal material such as a cylinder block and a liner for an inner wall surface thereof, and more particularly to a composite cast iron member having cast iron as a base material and a method for producing the same.
[0002]
[Prior art]
[Patent Document 1] Japanese Patent Application Laid-Open No. Hei 10-277725 Conventionally, for example, a copper alloy is adhered to the inner peripheral surface of a cylinder block in order to improve the slidability of the reciprocating motion of the piston. As disclosed in Patent Document 1, a method of attaching the copper alloy is to form a cylinder block main body with chromium / molybdenum steel or the like, heat the cylinder block main body, pack a flux, and pour a molten copper alloy. Solidified. Further, a cylinder block is formed by cutting a liner made of a copper alloy to a predetermined thickness.
[0003]
[Problems to be solved by the invention]
In the case of the above-mentioned conventional technology, since the cylinder block main body is formed of steel, processing man-hours and costs are required, which causes an increase in the cost of the cylinder block.
[0004]
On the other hand, in order to reduce costs, it is conceivable to cast the cylinder block body with cast iron.However, cast iron contains high concentration of carbon, and the bonding strength is weak even if copper alloy is poured into the cylinder inner wall, so that it cannot be put to practical use Met.
[0005]
The present invention has been made in view of the above-mentioned problems of the conventional technology, and provides a composite cast iron member capable of laminating non-ferrous metal materials with high strength using cast iron containing carbon and a method of manufacturing the same. With the goal.
[0006]
[Means for Solving the Problems]
The present invention is a composite cast iron member including a cast iron portion containing carbon, a decarburized layer formed on the surface of the cast iron portion, and a non-ferrous metal material layer joined to the decarburized layer and integrally laminated.
[0007]
The non-ferrous metal material layer may be a copper alloy, another aluminum alloy, or the like. The cast iron part is a cylinder block main body, and a non-ferrous metal material layer of a copper alloy is laminated on an inner wall surface of the cylinder block main body.
[0008]
Further, according to the present invention, a cast iron portion is cast by a predetermined mold, a decarburization process for removing carbon on the surface of the cast iron portion is performed, and a molten metal of a non-ferrous metal material is poured into the decarburized layer after the decarburization process. This is a method for manufacturing a composite cast iron member in which a metal material layer is integrally formed.
[0009]
The cast iron portion is a cylinder block main body, and a nonferrous metal material layer is integrally formed by pouring a molten metal of a copper alloy nonferrous metal material into an inner wall surface of the cylinder block main body.
[0010]
In the decarburization treatment, sand iron is laminated on the surface of the cast iron part and heated to 800 to 1100 ° C. to oxidize carbon in the cast iron part. Alternatively, the decarburization treatment may be such that the surface of the cast iron portion is placed in a fluidizing gas atmosphere containing carbon monoxide and carbon dioxide and heated to 800 to 1100 ° C. to oxidize the carbon of the cast iron portion. good.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a composite cast iron member according to an embodiment of the present invention and a method for manufacturing the same will be described with reference to the drawings. FIGS. 1 and 2 show a first embodiment of the present invention. The composite cast iron member of this embodiment relates to a cylinder block 10. The cylinder block 10 includes a cylinder block body 12 which is a cast iron portion containing carbon, a decarburized layer 12a formed on the inner wall surface of a cylinder 13 of the cylinder block body 12, and joined to the decarburized layer 12a to be integrally formed. And a non-ferrous metal material layer 14 laminated. As the non-ferrous metal material layer 14, for example, a layer containing 12.65 wt% of Sn, 8.61 wt% of Pb, and 1.71 wt% of Ni is used. In addition, alloys such as brass, bronze, phosphor bronze, lead bronze, and aluminum bronze may be used.
[0012]
In the method of manufacturing the cylinder block 10 of this embodiment, the cylinder block main body 12 is cast using a predetermined mold, and a decarburization process for removing carbon on the inner wall of the cylinder 13 of the cylinder block main body 12 is performed. In this decarburization treatment, as shown in FIG. 1 (a), iron sand 15 which is a powder of ferrous oxide is packed in a cylinder 13 or applied to the inner wall surface of the cylinder 13 to reach 800 to 1100 ° C. Heat to a high temperature to oxidize the carbon in the cylinder. The heating temperature is, for example, 930 ° C. in an electric furnace, and heating is performed for several hours. The relationship between the heating time at this temperature and the thickness of the decarburized layer is as shown in the graph of FIG. The reaction taking place here is as follows.
FeO + C = Fe + CO
[0013]
Thus, carbon on the surface of the cylinder 13 is removed as carbon monoxide (CO).
[0014]
After that, the iron iron 15 is cooled, the iron sand 15 is removed from the inside of the cylinder 13, a flux is put in, and a molten copper alloy 17 for forming the non-ferrous metal material layer 14 is poured into the cylinder 13 as shown in FIG. ,Cooling.
[0015]
After the molten copper alloy 17 is solidified as shown in FIG. 1C, the non-ferrous metal material 14a in the cylinder 13 is cut into a cylindrical shape as shown in FIG. Formed. Thus, a non-ferrous metal material layer 14 is formed on the inner wall surface of the cylinder 13.
[0016]
According to the composite cast iron member of this embodiment and the method of manufacturing the same, the cylinder block main body can be cast from cast iron, which is easy to manufacture, inexpensive, and has a non-ferrous metal of copper alloy on the inner wall surface of the cylinder cylinder 13. Even when the material layer 14 is formed, the bonding strength at the laminated portion is high, and the non-ferrous metal material layer 14 does not peel off. This joining strength, when a tensile test was performed using a test piece including the boundary between the cast iron and the copper alloy formed by this casting method, no fracture occurred at the joint portion with any of the plurality of test pieces, and the copper alloy portion broke. . Therefore, it was found that the joint between the cast iron part and the copper alloy part manufactured by this method was higher than the strength of the copper alloy itself.
[0017]
Next, a second embodiment of the present invention will be described with reference to FIG. Here, the same components as those in the above embodiment are denoted by the same reference numerals, and description thereof is omitted. The composite cast iron member of this embodiment also relates to a cylinder block. The cylinder block 20 of this embodiment includes a central hole 21 formed at the center and having a large diameter, and eleven cylinder holes 23 formed therearound. On the inner wall surface of the cylinder hole 23, a non-ferrous metal material layer 14 made of a copper alloy is formed.
[0018]
In the method of manufacturing the cylinder block 20 of this embodiment, first, as shown in FIG. 3A, the cylinder block body 22 is cast from cast iron. Thereafter, iron iron sand 15 of ferrous oxide is filled or applied to the cylinder hole 23. And it heats at 900 degreeC for 2 hours. Thereby, carbon on the inner wall surface of the cylinder hole 23 is removed at a depth of about several hundred μm, and a decarburized layer 22a is formed as shown in FIG. 3B. Thereafter, as shown in FIG. 3C, a molten copper alloy 17 at about 1200 ° C. is poured into each cylinder hole 23. Then, as shown in FIG. 3E, a hole having a predetermined diameter is formed in the non-ferrous metal material 14a in which the molten copper alloy 17 has been solidified as shown in FIG. .
[0019]
According to the cylinder block 20 of this embodiment, a large number of cylinder holes 23 can be easily formed by cast iron by casting, and the non-ferrous metal material layer 14 in the cylinder holes 23 is also easily and firmly made of a copper alloy. Can be formed.
[0020]
The composite cast iron member of the present invention is not limited to the above embodiment, but can be widely used for forming a non-ferrous metal layer on a cast product other than the cylinder block.
[0021]
In addition to the above, in the decarburization treatment, the surface of the cast iron part is placed in a fluidized gas atmosphere containing carbon monoxide and carbon dioxide and heated to 800 to 1100 ° C. to oxidize and remove the carbon in the cast iron part. What you do. In this case, at a temperature of 700 ° C. or more, which is a critical temperature for forming a decarburized layer, and preferably at a temperature of 800 to 1100 ° C., the carbon in the cast iron becomes carbon monoxide (CO) by the following reaction to perform decarburization. Is
C + CO2 = 2CO
[0022]
The composite cast iron member of the present invention is not limited to the above embodiment, and includes gray cast iron and stadium black smoke cast iron. Further, the non-ferrous metal material may be an alloy such as brass, bronze, phosphor bronze, lead bronze, and aluminum bronze, and can be appropriately used as a composite material of cast iron and an appropriate non-ferrous metal material.
[0023]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to the composite cast iron member of this invention and its manufacturing method, a cylinder block main body etc. can be cast with cast iron, and manufacture is easy and cost is low. Moreover, since the surface of the cast iron portion is decarburized and the non-ferrous metal material layer is laminated, the joining strength of the joint portion between the cast iron portion and the non-ferrous metal material layer is extremely high, and the cast iron portion is not easily separated.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view showing a manufacturing process of a composite cast iron member according to a first embodiment of the present invention.
FIG. 2 is a graph showing a relationship between a decarburization time and a decarburized layer of the composite cast iron member of the embodiment.
FIG. 3 is a schematic perspective view showing a manufacturing process of a composite cast iron member according to a second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Cylinder block 12 Cylinder block main body 12a Decarburization layer 13 Cylinder cylinder 14 Nonferrous metal material layer 14a Nonferrous metal material 15 Sand iron 17 Molten copper alloy

Claims (8)

A composite cast iron member comprising: a cast iron portion containing carbon; a decarburized layer formed on a surface of the cast iron portion; and a non-ferrous metal material layer joined to the decarburized layer and integrally laminated. The composite cast iron member according to claim 1, wherein the non-ferrous metal material layer is a copper alloy. 3. The composite cast iron member according to claim 1, wherein the cast iron portion is a cylinder block main body, and the non-ferrous metal material layer is laminated on an inner wall surface of the cylinder block main body. A cast iron part is cast with a predetermined mold, a decarburization process for removing carbon on the surface of the cast iron portion is performed, and a molten nonferrous metal material is poured into the decarburized layer after the decarburization process to integrate the nonferrous metal material layer. Forming a composite cast iron member. 5. The method according to claim 4, wherein the non-ferrous metal material is a copper alloy. The composite cast iron according to claim 4 or 5, wherein the cast iron portion is a cylinder block main body, and a nonferrous metal material layer is integrally formed by pouring a molten metal of the nonferrous metal material into an inner wall surface of the cylinder block main body. A method for manufacturing a member. 7. The composite cast iron member according to claim 4, 5 or 6, wherein the decarburizing treatment comprises laminating sand iron on the surface of the cast iron portion, heating the cast iron portion to a high temperature, and oxidizing and removing carbon in the cast iron portion. Manufacturing method. In the decarburization treatment, the surface of the cast iron part is placed in a fluidized gas atmosphere containing carbon monoxide and carbon dioxide, and heated to 800 to 1100 ° C. to oxidize and remove the carbon in the cast iron part. The method for producing a composite cast iron member according to any one of claims 4, 5 and 6, wherein

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