JPH0892663A - Shaft and stirring vane for degassing device of nonferrous metal melt - Google Patents

Abstract

PURPOSE: To provide a blank for a shaft and stirring vanes for a degassing device for the melt of nonferrous metals alone or molten alloys of >=2 kinds of various kinds of the nonferrous metals which are extremely little in erosion and penetration to be the dominant cause for contamination and shorter life of the molten metal. CONSTITUTION: The shaft and stirring vanes for the degassing device for the melt of the nonferrous metals alone, such as Al, Mg, Zn, Pb and Sn, and the molten alloys of >=2 kinds of various kinds of the nonferrous metals are formed of materials whose constituting components are SIALON/BN base. The Z value in the chemical formula Si6- zAlzOzN8- z of the SIALON is 2.0 to 4.0. The content of BN is 0.5 to 50wt.%. As a result, the shaft and stirring vanes which have the longer life and are maintenance-free are obtd, and the high quality of the products of the nonferrous metals alone, such as Al, Mg, Zn, Pb and Sn, and the alloys of >=2 kinds of various kinds of the nonferrous metals is enhanced.

Description

Detailed Description of the Invention

[0001]

The present invention relates to Al, Mg, Zn, P
The present invention relates to a shaft and a stirring blade for a molten metal degassing device of a non-ferrous metal such as b and Sn, and various non-ferrous metals of two or more types.

[0002]

2. Description of the Related Art Generally, a shaft and a stirring blade for stirring molten metal are used in a treatment process using a non-ferrous metal simple substance such as Al, Mg, Zn, Pb and Sn and an alloy molten metal degassing device of two or more kinds of various non-ferrous metals. It is necessary, and it is desired that the shaft and the stirring blade have high corrosion resistance against molten metal and flux and have a long life. Conventionally, materials such as alumina, silicon nitride, carbonitride-silicide, graphite or steel have been used as materials for these shafts and stirring blades, but problems have arisen depending on the conditions of use. Generally, steel and graphite shafts and stirring blades are used, but steel shafts and stirring blades are not suitable for high-purity molten metal purification because they dissolve in the molten metal as iron impurities during degassing. On the other hand, with regard to graphite, the amount of impurities picked up is small, but oxidation of graphite at high temperature and permeation / melting loss of flux are likely to result in a short life. Silicon nitride / carbosilicon nitride is strong against melting damage / penetration but weak against spalling, so it is easily cracked during heating / cooling cycles.
Further, when it is made of alumina, it is difficult to apply because it has a high expansion property and cracks occur.

[0003]

Problems to be Solved by the Invention Al, Mg, Zn, P
b, Sn shafts and stirring blades for non-ferrous metals such as Sn and alloys of two or more kinds of various non-ferrous metals, and stirring blades for molten metal degassing equipment, which have extremely small melting loss and penetration that cause molten metal contamination and a short life. The purpose is to provide the material.

[0004]

Means for Solving the Problems Al, Mg, Zn, P
The non-ferrous metal such as b and Sn and the shaft and the stirring blade for the molten metal degassing device of various non-ferrous metals of two or more kinds are made of materials whose constituent components are SIALON / BN quality. SIALON has the chemical formula Si ₆ _zAlzOzN ₈ _
The Z value in z is 2.0 to 4.0. BN is 0.5
~ 50% by weight.

[0005]

[Function] A SIALON / BN shaft and stirring blade
It is dipped in a single element of non-ferrous metal such as 1, Mg, Zn, Pb, Sn or a molten alloy of two or more non-ferrous metals. The shaft and stirring blade according to the present invention will be described in detail below. Component is a SIALON / BN quality, SIALON Z values in its chemical formula Si ₆ _zAlzOzN ₈ _z in type beta 'has 2.0 to 4.0 and BN content in a weight ratio 0.5 to 50
%.

The manufacturing method is as follows: raw material adjustment → molding → drying and degreasing → processing → sintering. The starting materials are fired and finally compounded so as to have the above-mentioned constituents. That is, when using normal pressure sintering, Si ₃ N ₄ , AlN, and Al ₂ O ₃ powders are mixed so that the Z value is 2.0 to 4.0, and the sintering aid, the binder, and the BN powder are added. What was added in a fixed amount was mixed with a non-aqueous solvent such as acetone for 12 to 24 hours by tromil, spray-granulated, and provided for molding.

When the reaction sintering is used, Si, A
1 and Al ₂ O ₃ powders each had a Z value of 2.0 after the nitriding reaction.
The mixture is blended so as to be about 4.0, and the binder and BN powder are added in a predetermined amount, and the mixture is mixed with a nonaqueous solvent such as acetone for 12 to 24 hours, spray-granulated, and subjected to molding.

Here, the Z value is set to 2.0 to 4.0 because
If it is less than 2.0, the solid solution amount of Al ₂ O ₃ is small, so Si
_{This is} because the properties of ₃ N ₄ become closer to that of N ₄ itself, and the corrosion resistance and oxidation resistance become insufficient. On the other hand, when Z exceeds 4.0, the corrosion resistance and the like improve, but the thermal shock resistance and strength decrease. Because it is. Further, the amount of BN was set to 0.5 to 50% by weight, but if it exceeds 50%, the tendency of BN to inhibit the formation and sintering of SIALON is too strong, the strength is remarkably lowered, and it tends to be a problem in practical use.

The molding is usually carried out by a uniaxial molding method or a hydrostatic molding method, but in some cases it is also possible to carry out slip casting without granulating the raw material. The molded body is dried and volatilized to remove binders (degreasing), and then processed and sintered. In the case of normal pressure sintering, 165 in a nitrogen atmosphere
0 to 1800 ° C., holding time is preferably 5 to 10 hours,
The higher the temperature, the shorter the holding time should be. In the case of reaction sintering, it is performed at 1400 to 1600 ° C. in a nitrogen atmosphere, and the holding time is preferably 5 to 10 hours, although it depends on the shape.

[0010]

EXAMPLES Next, examples will be described. SIALON /
As the BN quality, a BN amount of 30% by weight, a test body in which the Z value in Si ₆ _zAlzOzN ₈ _z of the chemical formula of SIALON was changed to 1.0 to 5.0 in calculation, and SIALON
The Z value was set to 3.0 and the BN amount was changed to 0 to 60% by weight to prepare a test body. Next, each of the test pieces cut out to a size of □ 20 × 250 mm was immersed in magnesium melted at 1000 ° C. for 120 hours, and the melting loss amount, metal permeation amount, and oxidation loss amount were measured. The results are shown in Tables 1 and 2.

[0011]

[Table 1]

[0012]

[Table 2]

Next, SIALON / BN quality (Z = 3.0,
A □ 20 × 250 mm test piece was prepared with BN = 30% by weight), and an immersion test in metal / flux was performed. As conditions, magnesium alloy 2.0kg and flux 5
The operation of melting 00 g together in a # 20 crucible and holding it at 800 ° C., stirring the test body while immersing it in the melt for 15 minutes, removing from the melt and allowing to cool is repeated up to 12 times. Similar tests were conducted on graphite, alumina, and silicon nitride specimens as comparative materials. Table 3 shows the results.

[0014]

[Table 3]

The test piece of the product of the present invention was not broken even after repeated 12 times, and the amount of melting loss, permeation and oxidation was extremely small. The graphite of the comparative product was broken at the sixth time, and the penetration reached the surface. Alumina was melted down when it was immersed. There was no melting loss, immersion and oxidation of the silicon nitride, but it cracked at the 9th time due to thermal shock.

[0016]

The SIA of the present invention is similar to the results of the above embodiment.
LON / BN shaft and stirring blade are made of Al, Mg, Z
Almost no melting loss and permeation from non-ferrous metal such as n, Pb, Sn, alloys of various non-ferrous metals and fluxes, and maintenance-free due to long life of shaft and stirring blade and Al, Mg , Zn, P
It is possible to improve the quality of products of non-ferrous metals such as b and Sn, and alloys of two or more non-ferrous metals.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location C04B 35/58 302 Y

Claims (3)

[Claims] 1. A shaft and a stirring blade for a molten metal degassing apparatus of a non-ferrous metal such as Al, Mg, Zn, Pb, and Sn, or a mixture of two or more kinds of non-ferrous metals.
A shaft and a stirring blade for a non-ferrous metal melt degassing device, which are characterized by IALON / BN quality. 2. The SIALON has a chemical formula of Si ₆ _zAlz.
Non-ferrous metal melt degasser shaft and a stirring blade of claim 1, Z value in OZN ₈ _z is characterized in that 2.0 to 4.0. 3. The shaft and stirring blade for a non-ferrous metal melt degassing apparatus according to claim 1, wherein the BN is 0.5 to 50% by weight.