JPH0677798B2 - Method for producing partially alloyed castings - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a method for producing castings, and more particularly to a method for producing partially alloyed castings.

2. Description of the Related Art When a certain part of a casting is required to have a certain characteristic, it is possible to form the entire casting with a metal material satisfying the characteristic. However, there are problems such that it is not possible to manufacture a casting having a complicated shape from the above, or the casting becomes expensive. For this reason, a method of producing a partially alloyed casting by remelting the surface of a specific portion of the casting using a laser beam, TIG arc, etc. as a heat source, and adding an alloying element to the remelted portion Being developed.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, since the method utilizing remelting as described above requires a complicated process, it is difficult to inexpensively produce a partially alloyed casting, and the casting is also difficult. It is difficult to uniformly alloy a specific part of the casting because only the surface part of the alloy can be alloyed, and there is extreme anisotropy in the crystal growth direction of the formed alloy phase. Therefore, there is a problem that anisotropy occurs in properties such as the alloyed strength of castings.

In view of the above-mentioned problems in the conventional method for producing a partially alloyed casting, the present invention provides a method capable of inexpensively and efficiently producing a partially alloyed casting. The purpose is to do.

Means for Solving the Problems According to the present invention, the above object is a casting made of a first metal, a part of which has a melting point higher than that of the first metal and the first metal In the method for producing a casting alloyed with a second metal that is alloyed with the metal, the second metal strip is formed into a shape substantially equal to the shape of the part, A porous molded body made of a strip of a second metal is formed, and only the molded body is placed in a portion for casting the part of the mold cavity of the mold, and the molten metal of the first metal is placed in the mold cavity. Is poured and the molten metal is allowed to penetrate into the molded body to alloy the first metal and the second metal in the entire region of the original molded body, and the molten metal in the mold cavity. Solidify at the entire area of the original compact It is achieved by a method for manufacturing a casting, which is characterized in that a molten alloy is formed.

According to the present invention, according to the present invention, the second metal strip is formed into a shape substantially equal to the shape of the portion to be alloyed, so that the second metal strip is porous. Is formed, and only the formed body is placed in a portion of the mold for casting the portion to be alloyed in the mold cavity, the molten metal of the first metal is poured into the mold cavity, and the molten metal is formed. By being penetrated into the body, the first metal and the second metal are alloyed in the entire area of the original molded body, and then the molten metal is solidified in the mold cavity, whereby the original molded body is formed. The alloy forms over the entire body area.

Therefore, by appropriately setting the size and shape of the molded body, the position in the mold cavity where the molded body is placed, etc., the desired specific portion of the casting can be set in a desired range according to the size and shape of the molded body. Can be alloyed over
This makes it possible to easily and inexpensively manufacture a casting in which a desired portion is substantially uniformly alloyed over a desired range, and the surface of the casting is remelted by a laser beam or the like to form a remelted portion. It is possible to reliably avoid the occurrence of problems such as anisotropy in the properties of the alloyed portion as in the case of adding an alloy element.

According to the present invention, the composition of the part to be alloyed can be set relatively freely by adjusting the volume ratio (bulk density) and type of the porous molded body made of the second metal strip. be able to. Further, in the method of the present invention, by using two or more moldings composed of the same or different second metal strips, it is possible to impart desired properties to two or more parts of the casting. The parts can be alloyed at the same time.

Incidentally, the second metal strips constituting the porous molded body in the method of the present invention may be powders, chips, flakes, fibers, fine wires, etc., and the strips are powders, chips, flakes, etc. When it is, these may be formed into a molded body by a method such as compression molding, and when the strips are fibers or fine wires, they may be formed into a molded body by a method such as binding.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Example 1 Fe powder having an average particle size of 25 μ and a purity of 99.4 wt% was prepared, and the powder was heated at 350 ° C. for 5 minutes in the atmosphere to forcibly oxidize the surface of the Fe powder. As shown in FIG. 1, it is introduced into the mold 3 of the compression molding device 2 and compressed at a pressure of 2700 kg / cm ² by the upper punch 4 and the lower punch 5 to obtain a shape and size of 80 mm in diameter and 10 mm in height. It was compression molded to form a porous molded body 6. In this case, the amount of oxygen on the surface of the Fe powder was 1.53 wt% and the bulk density of the compact was 4.7 g / cc.

Next, after preheating the molded body 6 to 600 ° C. in a vacuum furnace,
As shown in FIG. 2, it is arranged on the bottom surface in the mold cavity 9 of the mold 8 of the high-pressure casting apparatus 7, and in the mold cavity 9 pure aluminum having a hot water temperature of 800 ° C. (purity 99.
7 wt% of molten metal 10 was poured, and the molten metal was pressurized to a pressure of 1000 kg / cm ² by a plunger 11, and the pressurized state was maintained until the molten metal was completely solidified. After the molten metal was completely solidified, the columnar casting 13 was taken out from the mold 8 by the knockout pin 12. The casting 13 has a diameter of 80 mm and a height of 100 mm, and as shown in FIG.
It consists of a portion 14 alloyed with Fe and a portion 15 made of pure aluminum only.
It was confirmed to be alloyed with Fe.

FIG. 4 shows an optical microstructure of a cross section of the alloyed portion 14. When the EPMA analysis and the X-ray diffraction test were performed on this alloyed part, the part indicated by a
Fe, the part indicated by b is a mixed phase of AlFe and AlFe ₃ , the part indicated by c is Al ₂ Fe, and the part consisting of pure aluminum is scarcely left. Was recognized. Further, it can be seen from FIG. 4 that the above-mentioned phases are uniformly dispersed.

Further, when a tensile test was performed on the alloyed portion 14 at 450 ° C., the tensile strength of the portion was 45 kg / cm ²
It was confirmed that the strength was excellent and the heat resistance was excellent. Although not shown as a specific example, in the case of a casting made of pure aluminum, instead of Fe powder, nickel, vanadium, cobalt, tungsten, titanium, niobium, tantalum, silicon, molybdenum, copper or these Even if the alloy powder as the main component is used,
It was confirmed that alloying occurred between these powders and the molten pure aluminum, and an alloyed layer excellent in strength and heat resistance was obtained. Further, particularly when powder of silicon, molybdenum, manganese, or an alloy containing these as the main components is used, an alloyed layer having not only excellent strength and heat resistance but also excellent wear resistance is obtained. It was recognized that

Example 2 Example 1 described above except that the molten metal was replaced with pure magnesium having a purity of 99.8 wt% and the molten metal temperature was 750 ° C.
A cast product made of pure magnesium partially alloyed with iron was manufactured under the same procedure and under the same conditions as in the above.

FIG. 5 shows an optical microscope structure of a cross section of an alloyed layer formed by using nickel powder having an average particle size of 25 μ and a purity of 99.7 wt% as a powder constituting a porous molded body. When the EPMA analysis and the X-ray diffraction test were performed on this alloyed layer, the portion indicated by a is nickel, the portion indicated by c is a mixed phase of Mg ₂ Ni and MgNi ₂ , It was confirmed that in this alloyed layer, substantially no pure magnesium portion remained. It was also found that the alloyed layer was formed substantially in the entire region of the original molded body.

Also in the case of a cast product made of pure magnesium, by using various powders as shown in the following Table 1 as the powder constituting the porous molded body, the heat resistance of a part of the cast product made of pure magnesium, It has been found that properties such as wear resistance and thermal conductivity can be greatly improved.

Example 3 An Au powder having an average particle size of 7 μ and a purity of 99.9 wt% was compression molded by the compression molding apparatus shown in FIG.
A porous molded body having a size of 80 mm, a height of 10 mm and a bulk density of 5.4 g / cc was formed. Next, after preheating this molded body to 600 ° C. in a vacuum furnace, it is placed on the bottom wall of the mold cavity 9 of the mold 8 of the high-pressure casting apparatus shown in FIG. A pure tin melt with a wt% of 400 ° C. is poured, and the melt is solidified while being pressurized at a pressure of 500 kg / cm ² , resulting in a dimension of 80 mm in diameter and 100 mm in height, 10 mm from one end. A casting made of pure tin alloyed with gold was manufactured in the range.

Moreover, using a compression molding apparatus shown in FIG. 1, a titanium powder having a particle size of 10 μ or less and a purity of 97.6 wt% was used.
A porous molded body having a mm and a bulk density of 2.7 g / cc was formed. Next, after preheating the molded body to 600 ° C. in a vacuum furnace, the molded body is placed on the bottom wall in the mold cavity 9 of the mold 8 of the high-pressure casting apparatus shown in FIG. A pure copper molten metal having a purity of 99.9 wt% and a hot water temperature of 1250 ° C. is poured therein, and the molten metal is solidified while being pressurized at a pressure of 1000 kg / cm ² to have a dimension of 80 mm in diameter and 100 mm in height. A cast product made of pure copper in which a portion 10 mm from one end, that is, the entire region of the original molded body was alloyed with titanium was manufactured.

FIG. 6 shows an optical microscope structure of a cross section of a gold alloyed portion of a pure tin casting produced as described above. When the EPMA analysis and the X-ray diffraction test were performed on this alloy layer, it was found that the portion indicated by a is Au and the portion indicated by c is a mixed phase of AuSn and AuSn ₂ . . Further, FIG. 7 shows an optical microscope structure of a section of a titanium alloyed portion of a pure copper casting manufactured as described above. An EPMA analysis and an X-ray diffraction test were performed on this portion, and it was confirmed that the portion indicated by a is Ti and the portion indicated by c is a mixed phase of Ti ₂ Cu and TiCu. It was Further, it can be seen from FIG. 7 that the Ti powder used was fine, and thus the structure of the obtained alloyed layer was very fine.

Further, the above-mentioned alloyed portion with gold is superior in thermal conductivity to other portions, and the alloyed portion with titanium is superior in heat resistance to other portions. Was confirmed.

Although not shown as a specific example, as shown in Table 1 below, in the case of castings made of pure tin and castings made of pure copper, shown in Table 1 other than the above Au powder and Ti powder. The heat resistance and thermal conductivity of a part of each casting can be improved by using various powders shown in Table 1 below in the case of zinc castings and lead castings. It was recognized that it could be improved.

Example 4 A Ni wire having a diameter of 0.5 mm and a purity of 99.8 wt% was heated to 800 ° C. in air at 1
The surface was forcibly oxidized by heating for a time, whereby the oxygen content on the surface was adjusted to 0.73 wt%. Then the Ni wire 16
Is wound around a rod not shown in the drawing 30 times to obtain a cylindrical porous molded body 7 having an outer diameter of 80 mm, an inner diameter of 77 mm and a length of 5 mm as schematically shown in FIG. Was formed.

Next, the molded body 17 is preheated to 600 ° C. in a vacuum furnace, and then the molded body is die cast as shown in FIG.
Pure aluminum melt 24 with a purity of 99.7 wt% and a hot water temperature of 780 ° C. is placed in a mold cavity 21 defined by 18 fixed dies 19 and a movable die 20 and introduced into a casting sleeve 23 through an injection port 22. The plunger 25 by 500kg / cm
^By pressurizing with the pressure of ² , and solidifying the molten metal in the pressurized state, as shown in FIG. 10, a diameter of 80 mm,
It has a length of 100 mm, a range of 5 mm from one end and a range of 1.5 mm from the cylindrical outer peripheral surface, that is, a part 26 alloyed with nickel in the region of the original molded body, and a part 27 made of pure aluminum only. Then, a cylindrical casting 28 was manufactured.

FIG. 11 shows an optical microscope structure of a section perpendicular to the Ni line of the portion alloyed with nickel. An EPMA analysis and an X-ray diffraction test were carried out on a portion alloyed with nickel. The portion indicated by a was Ni, the portion indicated by b was Ni ₂ Al ₃ , and the portion indicated by c was Is indicated by Al
It was confirmed to have a eutectic structure with Al ₃ Ni.

The fine particles constituting the porous molded body according to this example are not limited to powders, and may be fine wires or fibers. When fine wires or fibers are used, an alloy layer having a specific directionality is obtained. In addition, it is understood that the directionality of the alloy layer can be arbitrarily set by appropriately setting the directions of the thin wires and fibers in the molded body. Further, from this example, it is presumed that the fine pieces constituting the porous molded body may be chips or thin pieces.

Although the present invention has been described above in detail with reference to some embodiments, the present invention is not limited to these embodiments, and various embodiments are possible within the scope of the present invention. It will be apparent to those skilled in the art.

[Brief description of drawings]

1 and 2 are sectional views showing a compression molding step and a high pressure casting step of the method for producing a casting according to the present invention, respectively.
The figure is a perspective view showing a columnar casting made of pure aluminum partially alloyed with iron, and FIG. 4 is an optical view of a section of the iron-alloyed portion of the casting shown in FIG. A photograph showing a microstructure, Fig. 5 is a photograph showing an optical microscope structure of a section of a nickel alloy portion of a pure magnesium casting, and Fig. 6 is an alloy of pure tin casting alloy with gold. Fig. 7 is a photograph showing the optical microscope structure of the cross section of the ablated part, Fig. 7 is a photo showing the optical microscope structure of the cross section of the titanium alloyed part of the casting made of pure copper, and Fig. 8 is a cylindrical shape made of Ni wire. FIG. 9 is a perspective view showing a porous molded body, FIG. 9 is a sectional view showing a casting process performed by a die casting apparatus using the molded body shown in FIG. 8, and FIG. 10 is shown in FIG. Fig. 11 is a perspective view showing a cylindrical cast product obtained by the casting process, Fig. 11 is the pure aluminum shown in Fig. 10. At um steel castings nickel is a photograph showing an optical microscopic structure of the cross-section perpendicular to the Ni lines alloyed portion. 1 ... Fe powder, 2 ... compression molding device, 3 ... mold, 4 ... upper punch, 5 ... lower punch, 7 ... high pressure casting device, 8 ... mold,
9 ... Mold cavity, 10 ... Molten metal, 11 ... Plunger,
12 ... Knockout pin, 13 ... Casting, 14 ... Alloyed part, 15 ... Part made of pure aluminum only, 16 ... Ni wire,
17 ... Molded body, 18 ... Die casting machine, 19 ... Fixed die, 20 ... Movable die, 21 ... Mold cavity, 22 ... Injection port, 23 ... Casting sleeve, 24 ... Molten metal, 25 ... Plunger, 26 ... Alloyed Part, 27 ... Part made of pure aluminum only, 28 ... Casting

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiro Kubo 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (56) References JP-A-60-121237 (JP, A) JP-A-51-28528 (JP, A)

Claims (4)

[Claims] 1. A casting made of a first metal, a part of which is alloyed with a second metal which has a melting point higher than that of the first metal and which is alloyed with the first metal. In the method for producing a casting, the second metal strip is molded into a shape substantially equal to the shape of the part to form a porous molded body made of the second metal strip. Then, only the molded body is arranged in a portion where the part of the mold cavity of the mold is cast, the molten metal of the first metal is poured into the mold cavity, and the molten metal is allowed to penetrate into the molded body. The first metal and the second metal are alloyed in the entire region of the original molded body by the above, and the molten metal is solidified in the mold cavity, whereby the entire region of the original molded body is formed. A method for producing a cast product, which comprises forming an alloy over the span. 2. The method for producing a casting according to claim 1, wherein the first metal is aluminum, magnesium,
A method for producing a casting, which is a metal selected from the group consisting of zinc, copper, tin, lead, and alloys containing them as a main component. 3. The method for producing a casting according to claim 1 or 2, wherein the second metal is tungsten, vanadium, iron, nickel, cobalt, titanium, zirconium, molybdenum, manganese, chromium. , Silicon, copper,
A method for producing a casting, which is a metal selected from the group consisting of silver, gold, niobium, tantalum, and alloys containing these as the main components. 4. The method for producing a casting according to any one of claims 1 to 3, wherein the molten metal is pressurized in the step of permeating the molten metal into the molded body. A method for producing a casting, comprising: