JP4711434B2 - Ceramic-containing additive and method for producing the same - Google Patents

Description

  The present invention relates to a ceramic-containing additive that is added to a molten iron-base alloy when a ceramic-dispersed iron-base alloy is obtained, and a method for producing the same.

  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 exhibits high strength and high rigidity, and a cast iron material with a large amount of C exhibits slightly higher wear resistance and corrosion resistance than steel materials, although the strength and rigidity are slightly inferior to those of steel materials.

  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 excellent corrosion resistance, 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. For example, Patent Document 1 discusses adding SiC particles to a molten iron-based alloy and then adding the molten metal or solidified product to cast iron to obtain a SiC dispersion cast composite material.

  In this way, it is recognized that the iron-based alloy (ceramic-dispersed composite material) in which ceramics such as SiC are dispersed has improved Young's modulus, for example, as compared with the iron-based alloy in which ceramics are not dispersed. .

  Further, in Patent Document 2, at least one of a silicon carbide ceramic sintered body in which metal boride solid solution particles are dispersed or a metal boride solid solution ceramic sintered body is used as martens-based high chromium cast iron or high Ni alloy-based grain cast iron. In addition, it is disclosed that a cast-in-comb composite is made by casting with martens-type high-speed steel or the like.

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

  As shown in Patent Document 1, when producing a composite material in which SiC is dispersed in an iron-based alloy, it is common to add an additive (formed body) containing SiC to the molten iron-based alloy. is there. This additive is produced, for example, by increasing the amount of Si in the molten iron-base alloy and precipitating it as SiC.

  In this case, however, Si may be dissolved in the base structure of the iron-based alloy. In this case, it becomes an additive with a small amount of SiC generated, and therefore, even if the additive is added to a cast iron material to produce a composite material, there is a problem that the Young's modulus is not improved so much.

  Further, since the technique described in Patent Document 2 is for casting a sintered body, it is not easy to disperse ceramics substantially uniformly in an iron-based alloy.

  The present invention has been made to solve the above-described problems, and a large amount of SiC is dispersed. Therefore, it is possible to obtain a ceramic-dispersed composite material having an improved Young's modulus as compared with an iron-based alloy as a base material. An object of the present invention is to provide a possible ceramic-containing additive and a method for producing the same.

In order to achieve the above object, the present invention provides a ceramic-containing additive that is added to a molten iron-base alloy when obtaining a ceramic-dispersed iron-base alloy,
When the mass of the ceramic-containing additive is 100% by mass, it contains 3 to 25% by mass of C, 7 to 35% by mass of Si, and 7 to 20% by mass of Al , with the balance being Fe and inevitable. specifically an impurity, the SiC as the ceramic formed by the said and the C Si and wherein from 9.5 to 85% by volume containing Mukoto.

  The base material of this additive is an iron-based alloy. Therefore, when added to the molten iron-based alloy to produce a ceramic-dispersed composite material, the base iron-based alloy is quickly dissolved by the molten metal. For this reason, since ceramics (SiC) disperse | distributes substantially uniformly in a molten metal, the ceramic dispersion | distribution composite material in which SiC disperse | distributed substantially uniformly can be obtained easily after all.

  Moreover, in this additive material, Al is dissolved in the base structure of the iron-base alloy that is the base material. Therefore, solid solution of Si into the base structure is suppressed, and for this reason, the amount of Si bonded to C increases. That is, since a large amount of SiC is contained, even when a small amount of the additive is added, a ceramic-dispersed composite material having remarkably excellent characteristics can be easily obtained.

Further, the present invention is added to the molten iron-based alloy when obtaining a ceramic-dispersed iron-based alloy , and 3 to 25% by mass of C when the mass of the ceramic-containing additive is 100% by mass, A method for producing a ceramic-containing additive containing 7 to 35% by mass of Si and 7 to 20% by mass of Al, the balance being Fe and inevitable impurities ,
A step of adding Al in a ratio of 7 to 20% by mass with respect to a molten metal containing 3 to 25% by mass of C and 7 to 35% by mass of Si and the balance being Fe and inevitable impurities,
A step of using the molten metal to which Al is added as a solidified body and chemically combining the C and the Si to form SiC as the ceramic;
It is characterized by having.

  As described above, in the present invention in which Al is added, Si is suppressed from being dissolved in the base structure of the iron-based alloy. Since this Si combines with C to form SiC, an additive containing a large amount of SiC can be obtained easily and simply.

  According to the present invention, Al is added to the molten iron-base alloy to suppress the solid solution of Si in the base structure of the iron-base alloy, thereby increasing the amount of SiC generated. An additive containing a large amount of SiC can be easily produced.

  Moreover, since the base material of the additive is an iron-based alloy, it quickly dissolves when added to the molten iron-based alloy, and SiC is dispersed substantially uniformly in the molten metal. By solidifying the molten metal, a ceramic dispersed composite material in which SiC is dispersed substantially uniformly is obtained. Such a ceramic-dispersed composite material has various characteristics superior to an iron-based alloy as a base material. For example, it shows a large Young's modulus.

  Hereinafter, preferred embodiments of the ceramic-containing additive and the method for producing the same according to the present invention will be described in detail with reference to the accompanying drawings.

  The ceramic-containing additive according to the present embodiment uses an iron-based alloy as a base material, and SiC is dispersed in the base material. Note that Al is dissolved in the base structure of the iron-based alloy. The shape of the additive can be, for example, a disk shape or a cylindrical shape, but is not particularly limited to these shapes.

  Here, when an instrumental analysis is performed on the ceramic-containing additive, it is confirmed that the elements present in the ceramic-containing additive are Fe, C, Si, and Al. Fe is an element derived from the base material (iron-based alloy), and C and Si are elements derived from the base material and SiC. Moreover, Al exists as a solid solution in the base structure of the iron-based alloy as described above.

  And the ratio of C, Si, and Al is 3-25 mass%, 7-35 mass%, and 7-20 mass%, respectively, and the remainder is Fe and inevitable impurities.

  Further, SiC occupies at least 9.5% by volume of the total volume of the ceramic-containing additive. In other words, SiC is present in the ceramic-containing additive at a ratio of 9.5% by volume or more. Since the initial Si amount is 35% by volume, the ratio of SiC is 85% by volume at the maximum.

  This ceramic-containing additive can be produced through a first step of adding Al to the molten iron-based alloy and a second step of solidifying the molten metal.

  That is, first, in a first step, a molten iron-based alloy containing a predetermined amount of C and Si and the balance being Fe and inevitable impurities is prepared. Among these, a part of Si and C is consumed by forming SiC in the second step described later.

  Here, the ratio of C in the molten metal is set to 3 to 35 mass%. If the amount is less than 3% by mass, the amount of SiC generated during the second step is reduced. That is, since it becomes an additive with a low content of SiC, it is necessary to add a large amount of additive in order to obtain a ceramic-dispersed composite material excellent in various properties. On the other hand, when the content is more than 35% by mass, even when the ceramic-containing additive is added to the molten iron-based alloy when the ceramic-dispersed composite material is produced, the iron-based alloy that is the base material of the ceramic-containing additive is Since it is difficult to dissolve, it is not easy to disperse SiC.

  Moreover, the ratio of Si is set to 7-35 mass%. Similarly to the above, when the amount is less than 7% by mass, the amount of SiC generated is small, and when it exceeds 35% by mass, it is not easy to obtain a ceramic-dispersed composite material in which SiC is well dispersed.

  Then, Al is added so that it may become a ratio of 7-20 mass% with respect to this molten metal. If it is less than 7% by mass, the amount of SiC produced is small. Moreover, even if SiC is added at a rate exceeding 20% by mass, the amount of SiC produced is saturated and becomes substantially constant, which is disadvantageous in terms of cost.

  The molten metal thus obtained is then solidified in the second step.

  At the time of this solidification, a base structure of an iron-based alloy is formed by Fe, C, and Si. Next, Al dissolves in the base structure. For this reason, it is suppressed that excess Si dissolves in the base tissue.

  Excess Si that is not solid-dissolved in the base tissue chemically bonds with excess C. As a result, SiC is formed. As the solidification further proceeds, a ceramic-containing additive having a predetermined shape containing a large amount of SiC is obtained.

  Here, the relationship between the amount of Si in the molten metal and the amount of generated SiC in the ceramic-containing additive is shown as a graph in FIG. In addition, Al amount was made into additive-free, 7 mass%, and 15 mass%. From FIG. 1, it is clear that the amount of SiC produced can be increased by adding Al.

  Although the amount (ratio) of SiC produced depends on the initial amount of Si and Al added in the molten metal, since both Si and Al are at least 7% by mass, at least 9.% of the total volume of the ceramic-containing additive. Occupies 5%. Moreover, since Si and Al are 35 mass% and 20 mass% at maximum, it will be 85 mass% at maximum.

  That is, according to the present embodiment, since Al is added to the molten iron-based alloy, the amount of Si dissolved in the base structure of the iron-based alloy is controlled. For this reason, a large amount of SiC is added. It becomes possible to obtain the ceramic containing additive to contain.

  As described above, the ceramic-containing additive thus obtained contains 3 to 25 mass%, 7 to 35 mass%, and 7 to 20 mass% of C, Si, and Al, respectively, with the balance being Fe. And inevitable impurities. Moreover, SiC is contained in the ratio of 9.5-85 volume%.

  This ceramic-containing additive can be used, for example, to improve the Young's modulus of a cast iron material. In this case, casting may be performed after the ceramic-containing additive is added to the cast iron melt.

  As can be understood from the above, the base material of the ceramic-containing additive is an iron-based alloy. Therefore, the base material of the ceramic-containing additive rapidly dissolves when added to the molten cast iron material (iron-based alloy), and as a result, SiC is dispersed substantially uniformly in the molten metal. For this reason, a ceramic dispersed composite material in which SiC is dispersed substantially uniformly in the cast iron material can be obtained.

  The ceramic-containing additive was added to a molten FCD450 equivalent material and then cast to obtain a ceramic-dispersed composite material. The Young's modulus of this ceramic-dispersed composite material was measured. For comparison, the Young's modulus of the SiC dispersion composite prepared by adding the ceramic-containing additive prepared without adding Al to the melt of the FCD450 equivalent material and the FCD450 equivalent material was also measured. The results are also shown in FIG. From FIG. 2, it is clear that a ceramic-dispersed composite material having a remarkably large Young's modulus as compared with cast iron material can be obtained by using a ceramic-containing additive material to which Al is added.

  Further, when the wear resistance was compared, a result was obtained that the ceramic-dispersed composite material obtained by adding the ceramic-containing additive containing Al was superior.

  In the embodiment described above, Al is added to the molten metal containing C and Si to produce a ceramic-containing additive, but the base material of the ceramic-dispersed composite material is a so-called special cast iron material. Therefore, a ceramic-containing additive may be configured by further adding another metal element.

It is a graph which shows the relationship between the amount of Si in a molten metal, and the production | generation SiC amount in a ceramic containing additive. A ceramic-dispersed composite material obtained by adding the ceramic-containing additive according to the present embodiment to the molten FCD450 equivalent material, and SiC obtained by adding the Al-free ceramic-containing additive to the FCD450 equivalent material molten metal It is a measurement result of each Young's modulus of a dispersion composite material cast iron material and FCD450 equivalent material.

Claims (2)

A ceramic-containing additive that is added to a molten iron-based alloy when obtaining a ceramic-dispersed iron-based alloy,
When the mass of the ceramic-containing additive is 100% by mass, it contains 3 to 25% by mass of C, 7 to 35% by mass of Si, and 7 to 20% by mass of Al , with the balance being Fe and inevitable. specifically an impurity, ceramic containing the additive material, wherein from 9.5 to 85% by volume containing Mukoto the SiC as the ceramic formed by the said and the C Si. When the ceramic-dispersed iron-based alloy is obtained, it is added to the molten iron-based alloy, and when the mass of the ceramic-containing additive is 100% by mass, 3 to 25% by mass C and 7 to 35% by mass A method for producing a ceramic-containing additive containing Si and 7 to 20% by mass of Al, the balance being Fe and inevitable impurities ,
A step of adding Al in a ratio of 7 to 20% by mass with respect to a molten metal containing 3 to 25% by mass of C and 7 to 35% by mass of Si and the balance being Fe and inevitable impurities,
A step of using the molten metal to which Al is added as a solidified body and chemically combining the C and the Si to form SiC as the ceramic;
The manufacturing method of the ceramic containing additive characterized by having.

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