JP4684985B2 - Manufacturing method of composite material - Google Patents

Description

  The present invention relates to a method for manufacturing a composite material in which a composite material is provided by casting a pellet containing ceramics into a metal.

  Iron-based alloys have various properties that vary depending on the form of the metal structure, the type of contained components, and their proportions. For example, a steel material with a small amount of C shows high strength and high rigidity, and a cast iron material with a large amount of C is slightly inferior to steel material in strength and rigidity, but is inexpensive and superior in cost.

  By the way, when providing a structural material, corrosion resistance and high rigidity may be required for the structural material at the same time. At this time, for example, when casting is performed using a cast iron material having a low cost, there is a concern that the rigidity of the obtained structural material is not sufficient.

  From such a point of view, a metal matrix composite material has been proposed in which ceramics are dispersed in a metal material and the properties required of the ceramic material are secured while utilizing the properties of the metal material. As a method for producing this type of metal matrix composite material, a composite casting method is exemplified. In other words, this is a technique in which ceramic powder is added to a molten metal for casting.

  However, when the compocast method is performed, the ceramic powder is easily separated from the molten metal, and therefore, there is a disadvantage that it is not easy to disperse the ceramic. When casting is performed with the ceramic powder separated, when the molten metal is solidified to form a cast product, the ceramic phase and the metal phase are separated in the cast product.

  In order to avoid such phase separation, as described in Patent Document 1, after adding SiC particles to the molten iron-based alloy, this molten or solidified product is added to the molten cast iron material to solidify. As described in Patent Document 2, at least one of silicon carbide ceramics sintered body in which metal boride solid solution particles are dispersed or metal boride solid solution ceramics sintered body is used. It is conceived that a cast-in-line composite is made by casting with marten-based high chromium cast iron, high Ni alloy-based grain cast iron, martens-based high-speed steel, or the like.

Japanese Patent Publication No.7-11045 JP 2004-307893 A

  The present invention has been made in connection with the above-described technology, and is capable of suppressing the generation of shrinkage nests and miniaturizing the structure, and further provides a method for producing a composite material having excellent Young's modulus. The purpose is to provide.

In order to achieve the above object, the present invention is a method for producing a composite material in which a composite material is provided by casting a pellet containing a ceramic phase into a metal,
Providing 20% by volume or more of a ceramic phase and providing the pellets with the balance being a metal phase;
Adding the pellets to the molten metal at a ratio of 3 to 15% by mass, and performing casting immediately thereafter;
Providing the composite material in which the pellet is cast by solidifying the molten metal;
It is characterized by having. The pellet may be a molded body or a pulverized product.

  By performing casting using the molten metal immediately after the pellets are added to the molten metal, the occurrence of shrinkage can be suppressed. Moreover, in this case, the cast product (composite material) exhibits an excellent Young's modulus compared to the base metal due to the presence of the ceramic phase. Eventually, the composite material is more rigid than the base metal.

  When a molten iron-based alloy is selected as the molten metal, it is preferable to select an Fe—Si alloy that is an inoculum as the metal phase.

  The pellet diameter is preferably 0.25 to 3 mm. This is because the ceramic phase is difficult to separate from the molten metal.

  Moreover, a suitable example of the ceramic phase includes at least one of TiC, VC, and SiC.

  According to the present invention, since casting is performed using the molten metal immediately after adding a pellet containing a predetermined amount of the ceramic phase to the molten metal, the occurrence of shrinkage can be suppressed. Moreover, since the cast product (composite material) which is the final product contains a ceramic phase derived from the pellets, it exhibits an excellent Young's modulus compared to the base metal.

  Preferred embodiments of the composite material manufacturing method according to the present invention will be described below in detail with reference to the accompanying drawings.

  The method for manufacturing a composite material according to the present embodiment includes a first step of providing pellets as a ceramic-containing additive, a second step of adding the pellets to the molten metal and casting, and solidifying the molten metal. And a third step of providing a cast product (composite material).

  In the first step, the pellet can be provided, for example, by molding a mixed powder obtained by mixing ceramic powder and metal powder. The shape of the pellet can be, for example, a disk shape or a cylindrical shape, but is not particularly limited to these shapes.

  Alternatively, a ceramic powder added to a molten metal may be solidified, or the ceramic phase may be crystallized or precipitated in the metal so that the ceramic phase is included in the metal. In these cases, there is no particular problem even if a pellet in which the ceramic phase and the metal phase are separated is produced.

  Furthermore, you may make it grind | pulverize the solid substance obtained as mentioned above.

  As described above, a pellet containing a ceramic phase and a metal phase is produced.

  Here, the ceramic phase in the pellet is set to 20% by volume or more. That is, when producing the pellet, the ceramic powder is added so as to occupy 20% by volume or more. If it is less than 20% by volume, the effect of improving the Young's modulus and consequently the rigidity is poor.

  The ceramic powder is preferably at least one of TiC, VC, and SiC. This is because a composite material in which these are dispersed in a metal material exhibits a higher Young's modulus than a metal material that is a base material.

  And it is preferable that the pellet diameter of a pellet is 0.25-3 mm. It is easy to isolate | separate from a molten metal as the pellet diameter of a pellet is less than 0.25 mm. Moreover, when a pellet having a pellet diameter larger than 3 mm is used, there is a tendency that the shrinkage cavity suppressing effect on the cast product is poor.

  On the other hand, the metal phase is not particularly limited, and the main component thereof may be the same as the main component of the molten metal or may be a different type. If the molten metal is an iron-based alloy such as cast iron, select an iron-based alloy as the metal phase. If the molten metal is a nickel-based alloy, select a nickel-based alloy as the metal phase. When the main components of the phase and the molten metal are the same component, the specific gravity of the molten metal and the pellet can be approximated, so that there is an advantage that the separation of the pellet from the molten metal can be suppressed.

  When the molten metal is an iron-based alloy, a preferred example of the metal phase is an Fe—Si alloy used as an inoculum.

  Next, in the second step, the above pellets are added to the molten metal. At this time, the amount of the pellet added is 3 to 15% by mass with respect to the molten metal. If it is less than 3% by mass, the shrinkage nest suppressing effect and the Young's modulus (rigidity) improving effect are poor. On the other hand, if added over 15% by mass, the temperature of the molten metal is remarkably lowered immediately after the addition, so that the so-called hot-rolling property is lowered and casting is difficult to proceed.

The pellets added to the molten metal are dispersed in the molten metal as pellets or with the surface layer dissolved. Immediately after preparing this molten metal, casting is performed in the next third step and further solidified. During this coagulation, the generation of shrinkage nests is suppressed.

  When solidification is completed, a composite material containing the ceramic phase contained in the pellet is obtained as a cast product. This composite material includes a ceramic phase, and thus exhibits a larger Young's modulus than the metal material that is the base material of the composite material.

  A material having a large Young's modulus has a large rigidity. That is, according to the present embodiment, it is possible to easily obtain a composite material having higher rigidity than the metal material of the base material.

  Here, a composite material obtained by adding 50% by volume of TiC to an Fe base material and adding a pellet (additive material) having a pellet diameter of 0.25 to 3 mm to an FCD450 equivalent material, an Ni base material Combined results of measuring Young's modulus of a composite material obtained by adding 35% by volume of SiC to the FCD450 equivalent material and pellets having a pellet diameter of 0.25 to 3 mm are added to the FCD450 equivalent material. As shown in FIG. From FIG. 1, it is clear that a composite material having a remarkably large Young's modulus as compared with cast iron material can be obtained by adding pellets containing a ceramic phase.

  In order to make the base material of the composite material a so-called special cast iron material, another metal element may be further added to form a pellet.

  The pellet diameter can be adjusted by, for example, selecting the pulverized product with a predetermined sieve.

It is a measurement result of each Young's modulus of the composite material which concerns on this Embodiment, and FCD450 equivalent material.

Claims (3)

A method for producing a composite material in which a composite material is provided by casting a pellet containing a ceramic phase into a metal,
A step of providing the pellet having a ceramic phase of 20% by volume or more, the balance being a metal phase, and a diameter of 0.25 to 3 mm ;
After adding the pellet to the molten metal at a ratio of 3 to 15% by mass, the pellet is undissolved, or when the surface layer is dissolved , casting using the molten metal ,
Providing the composite material in which the pellet is cast by solidifying the molten metal;
A method for producing a composite material, comprising:   The method for manufacturing a composite material according to claim 1, wherein a molten iron-based alloy is selected as the molten metal, and an Fe—Si alloy is selected as the metallic phase. 3. The method for manufacturing a composite material according to claim 1, wherein at least one of TiC, VC, and SiC is selected as the ceramic phase.

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