JP4852737B2 - Method for producing recycled Fe-Al composite material - Google Patents

Description

  The present invention relates to a method for producing a composite material by melting a waste material containing iron and a waste material containing aluminum.

Iron and aluminum are indispensable metals for our lives and are manufactured by refining. In refining these metals, the energy required to recycle the metal that has already been distributed to the market as a product (this is called “secondary refining”) is the energy required for refining virgin material from ore (this is called “primary refining”). It is estimated that it is much less than the energy required for As for metal resources, as long as they are mined resources, there is concern about depletion. Therefore, secondary refining is an essential consideration from the viewpoint of energy consumption and environmental load reduction.

However, current secondary refining often requires more energy than primary refining. This is due to the difficulty in sorting and collecting metals and the complex packaging problems associated with the reduction in the size and weight of products that use metals, while reducing the quality of waste materials, while refining metals from such low-quality waste materials. This is because the technology to do this has not been established, and it is necessary to return the waste material containing iron and aluminum to a high quality state, for example, a virgin material or a state close thereto, before performing secondary refining. As a result, the cost of secondary refining is rather high.

Although secondary refining technology is an indispensable technology in modern society as described above, the high cost is an obstacle to the spread of secondary refining from an industrial viewpoint. Therefore, in order to promote the popularization of secondary refining, it is necessary to establish a technology for refining metals from low-grade waste materials that reduces costs.

Non-Patent Document 1 below suggests a technique for manufacturing a recycled Fe—Al composite material using high carbon chrome steel grinding sludge and waste aluminum can material.
258th Annual Meeting of the 132nd Annual Meeting of the Japan Institute of Metals

  The invention described in Non-Patent Document 1 is useful in that it is possible to produce a recycled Fe-Al composite material using grinding sludge, which is a low-grade waste material, and a waste aluminum can material. It is desirable to further improve the properties.

  Then, this invention pays attention to the said subject, and it aims at providing the method of manufacturing the recycle type Fe-Al composite material which improved abrasion resistance more.

In order to achieve the above object, the present invention specifically adopts the following means.
As a first means, a waste material containing iron, a waste material containing aluminum, and at least one of group IVA element, group VA element, group VIA element or group VIIA element (hereinafter simply referred to as “carbide-forming element”), It is set as the method of manufacturing a composite material by melt | dissolving.
The inventors focused on carbon contained in waste materials in general when a waste material containing iron and a waste material containing aluminum are mixed to produce a Fe-Al composite material. In this case, carbon was contained in the form of Fe ₃ AlC _0.5 in the Fe ₃ Al matrix, and it was thought that this could be contributed to the improvement of mechanical properties as another carbide in some form. It was experimentally confirmed that when this carbon was used and a carbide forming element was added and dissolved together, the wear resistance was greatly improved. In addition, even if it is a low-grade waste material, it is possible to obtain a composite material with improved mechanical performance by actively utilizing this. Note that by adding a carbide-forming element at the time of dissolution, a composite material in which micron-order carbides are dispersed by a single dissolution can be easily produced.

Here, the “waste material” means a powder shape of 1 mm or less or a small piece shape of 5 cm or less, and examples of the waste material include low-quality items such as scrap-like materials and powder shapes. The effect of this means can be obtained even if it is high quality as long as it is waste material, but the effect of this means becomes even more remarkable when the waste material is low quality.
In addition, scrap materials containing iron correspond to ground sludge powder and scrap automobile parts, and scrap materials including aluminum include scrap aluminum cans, scrap steel cans (the lid part is aluminum), scrap building material aluminum members, etc. .

In this means, various melting methods can be employed as long as the waste material can be melted. For example, a method using a so-called high-frequency furnace, a method using an electric furnace, or the like can be employed. As the atmosphere in which the solubility can be used air (air) or an inert gas (Ar, N _2, etc.). In the case of the atmosphere, the waste material can be dissolved as it is in a furnace under the atmosphere, which is very advantageous in terms of cost. In the case of an inert gas, the oxidation of iron in the waste material can be prevented, so that the performance is improved. This is advantageous in that an improved composite material can be obtained.

  Further, in this means, “Group IVA element, Group VA element, Group VIA element or Group VIIA element”, that is, “carbide forming element” is a transition element in the periodic table of elements, for example, Ti, V, Cr, Mn, Zr, Nb, Mo, Tc, Hf, Ta, W, Re, etc. are applicable. These elements are not particularly limited as long as they can form carbon (C) and carbides in the waste material.

  Further, in this means, the waste material containing iron or the waste material containing aluminum contains 5 at% or less of carbon with respect to the entire composite material, and the carbide forming element is dissolved so as to contain 5 at% or less with respect to the entire composite material. It is also desirable. This is an amount suitable for contributing to the improvement of the friction resistance that the carbide exerts on the composite material, and if the carbon is contained even in a trace amount, the friction resistance can be improved. On the other hand, if it exceeds 5 at%, the composite material may be fragile and mechanical strength may be reduced. In this case, it is also desirable that the amount of carbide element and carbon is 1: 1.

Moreover, in this means, it is also desirable that the waste material containing iron: the waste material containing aluminum is in the range of 65 to 74 at%: 35 to 26 at%. This is due to the fact that the range is necessary for forming Fe ₃ Al. This is because Fe ₃ Al is hard, has high yield strength from room temperature to high temperature, and is further known to have excellent oxidation resistance. It is also desirable for clarifying the invention that the composite material is Fe ₃ Al / TiC.

  Further, in this means, it is very useful to reduce the cost to perform the dissolution in an air atmosphere, and it is useful to improve the properties of the composite material to perform the dissolution in an inert gas atmosphere.

  In this means, it is also desirable that the composite material be used for train or automobile parts. In particular, since this composite material is excellent in friction resistance, it is particularly effective when used for a material for which friction resistance is desired, such as a break disk in an engine section.

  As mentioned above, the manufacturing method of the recycle type Fe-Al composite material which improved the abrasion resistance more can be provided.

  Hereinafter, the present invention will be described with reference to embodiments.

In this embodiment, powdery SUJ2 grinding sludge (see FIG. 1 (A)) having a diameter of about 1 μm to 1 mm is used as the waste material containing iron, and the diameter of about 1 mm to 30 mm is used as the waste material containing aluminum. The scrap (small piece) -shaped Al pellet (see FIG. 1B) having Ti was used as an example of “IVA group element, VA group element, VIA group element or VIIA group element”. The chemical components of SUJ2 grinding sludge are shown in Table 1 below, and the chemical components of Al pellets are shown in Table 2 below. In Tables 1 and 2, “Bal.” Indicates the balance.

In this example, a plurality of samples were prepared in which the blending amount of the waste material containing iron and the waste material containing aluminum was changed. Table 3 below shows blending amounts and the like. In Table 3, at% of Fe and at% of Al are shown including the amounts of other elements in the waste material excluding carbon.

  In this example, a commercially available high frequency furnace (manufactured by Daia Vacuum) was used as a melting method. The external appearance is shown in FIG. Further, Ar gas was used as the atmosphere during the dissolution. The melting was performed by sufficiently dissolving the waste material containing iron and the waste material containing aluminum at 1800 degrees, and then adding Ti to further dissolve at 1800 degrees. And after making it fully melt | dissolve, it cooled to 25 degree | times by casting to a casting_mold | template, and it casted in the rod shape of (phi) 12mmx285mm, and obtained the composite material. FIG. 3 shows a photograph of the composite material obtained for sample number 2.

And the structure | tissue was observed variously with respect to these created samples. In FIG. 4, the SEM photograph about the structure | tissue of the composite material of the sample number 2 is shown. As shown in FIG. 4, in this composite material, about 1 to 5 μm of carbide 1 (TiC) was dispersed in Fe ₃ Al as a parent phase. That is, carbides could be formed by adding Ti.

  FIG. 5 shows a transmission micrograph of the structure of the composite material. As shown in FIG. 5, a portion that could be inferred as square TiC was confirmed.

  In addition, FIG. 6 also shows the results of electron diffraction performed on the portion of the composite sample inferred as the square TiC in FIG. As shown in FIG. 6, it was concluded that this composite material was NaCl-type TiC.

  In addition, although the same analysis was performed also about the said sample numbers 1-4, all showed the same result (not shown).

On the other hand, the same analysis was performed for sample number 5, but results such as sample numbers 1 to 4 could not be obtained. FIG. 7 shows an SEM photograph of the sample No. 5 tissue. In addition, what looks like a rod shape in FIG. 7 is Fe ₃ AlC _0.5 .

Next, the amount of wear on these samples was measured.
In the measurement, an experimental sample was cut into φ8 mm × 25 mm from the composite material shown in FIG. 3 and performed by the Pin on Disk method. FIG. 8A shows a Pin test piece, FIG. 8B shows a Disk test piece, and FIG. 8C shows an outline of a Pin on Disk friction and wear tester. The disk test piece uses 1260Hv10 Al ₂ O ₃ .

The results of this friction and wear test are shown in FIG. In the figure, Re-Fe ₃ Al / TiC shows the result of the composite material according to the present example (the result of sample number 2), and Re-Fe ₃ Al shows the case where Ti of sample number 6 is not added. the results, the _Fe 3 Al as a result of _Fe 3 Al created from pure iron and pure aluminum, SUJ2 is a result of the SUJ2, FC200 denotes a result of FC200 (cast iron). As test conditions, the sliding speed was 0.42 m / s, the sliding distance was 754 m, and the load was 49 N, 98 N, 147 N, and 196 N. Moreover, the hardness of the composite material in each Pin test piece was as shown in Table 4 below. It was confirmed that the composite material according to this example was sufficiently harder than Fe ₃ Al, SUJ2, or the like. Of course, the same results were shown for sample numbers 1 to 4 (the figure was omitted because it was the same).

  According to the result of FIG. 9, the composite material according to the present example shows that the friction amount is reduced as compared with the other examples. In particular, even when the load was increased, the increase in the amount of friction was small compared to other materials, and it was confirmed that the difference from other materials was significant.

  As described above, the iron aluminide-based composite material can be easily produced by using the waste material and effectively utilizing the impurities contained in the waste material. It was also confirmed that the produced recycled composite material had excellent wear resistance characteristics.

The figure which shows the waste material containing iron and the waste material containing aluminum used in the Example The figure which shows the high frequency furnace used in the Example. The figure which shows the rod-shaped composite material manufactured in the Example. The SEM photograph of the structure | tissue of the composite material in an Example. The TEM photograph of the structure | tissue of the composite material in an Example. The figure which shows the result of the electron beam diffraction of the composite material in an Example. SEM photograph of composite material structure as a comparative example (Sample No. 5) The figure which shows the outline of a Pin test piece, a Disk test piece, and a Pin on Disk test apparatus. The figure which shows the test result of Pin on Disk.

Claims (5)

1 mm or less of waste material in the form of cutting sludge powder containing iron and carbon and waste material containing aluminum are melted by a high frequency furnace,
After the dissolution, a carbide-forming element containing at least one of Ti, Zr, V, and Nb is added and further dissolved to produce a composite material containing carbide so that the carbon content is within a range of 5 at% or less. A method ,
Waste material containing iron and carbon: A method for producing a composite material in which the waste material containing aluminum is in the range of 65 to 74 at%: 35 to 26 at%. The method of manufacturing a composite material according to claim 1, wherein the composite material is Fe ₃ Al / TiC.   The method for producing a composite material according to claim 1, wherein the melting is performed in an air atmosphere.   The method for producing a composite material according to claim 1, wherein the dissolution is performed in an inert gas atmosphere. The method for producing a composite material according to claim 1, wherein the composite material is used for parts of a train or an automobile.