JPH08311571A - Shaft and impeller for molten nonferrous metal degasifier - Google Patents

Abstract

PURPOSE: To provide a material for a shaft and impeller reduced in the erosion and infiltration causing molten metal contamination and short service life in the shaft and impeller for a device to degasify the molten nonferrous metal or the molten alloy of >=2 kinds of nonferrous metals. CONSTITUTION: The shaft and impeller for the device to degasify a molten nonferrous metal among Al, Mg, Zn, Pb, Sn, etc., or the molten alloy of >=2 kinds of nonferrous metals are formed with a material consisting of Sialon-BN- Mo. The Sialon is expressed by the chemical formula, Si6-x Alz Oz N8-z , where z is 2.0 to 4.0. The content of BN is controlled to 0.5-50wt.% and that of Mo to 1.0-10wt.%.

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 / carbocarbonitride siliceous material is strong in melting damage / penetration but weak in spalling, so it is easily cracked in the heating / cooling cycle. Further, when it is made of alumina, it is difficult to apply because it has a high expansion property and cracks occur. With regard to the quality of SIALON-BN, since the strength and wear resistance are low, the problem of wear occurs rather than the melting loss.

[0003]

Problems to be Solved by the Invention Al, Mg, Zn, P
b, Sn shafts and agitating blades for non-ferrous metals such as Sn, alloy shafts and agitating blades for alloy degassing equipment of two or more types of non-ferrous metals, with extremely low melting loss and penetration that cause melt contamination and a short life. The purpose is to provide the material.

[0004]

The present invention relates to Al, Mg, Z
The non-ferrous metal simple substance such as n, Pb, and Sn and the shaft and the stirring blade for the molten alloy degassing device of various non-ferrous metals of two or more kinds are made of a material whose constituent components are SIALON-BN-Mo quality. SIALON has the chemical formula Si ₆ _zA
Z value in lzOzN ₈ _z is 2.0 to 4.0. B
N is 0.5 to 50% by weight. Mo is 1.0 to 10% by weight. By adding Mo to SIALON-BN, the strength and wear resistance are increased, and the spalling resistance is hardly affected. Metallic Mo is included in the structure of SIALON-BN as an additive material, so that electric discharge machining can be performed and complicated machining is easy and cost is low.

[0005]

FUNCTION The SIALON-BN-Mo shaft and stirring blades are immersed in a single nonferrous metal such as Al, Mg, Zn, Pb, and Sn, or a molten alloy of two or more nonferrous metals. The shaft and the stirring blade according to the present invention will be described in detail. The constituents are SIALON-BN-Mo quality, SIALO
N is β ′ type and has a Z value of 2.0 to 4.0 in the chemical formula Si ₆ —zAlzOzN ₈ —z and a BN content of 0.
5 to 50% and Mo content is 1.0 to 10% by weight.
Is.

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 normal pressure sintering is used, powders of Si ₃ N ₄ , AlN, and Al ₂ O ₃ are blended so that the Z value is 2.0 to 4.0, and the sintering aid, binder, BN powder, and Mo are mixed. Add a certain amount of powder to Tromyl with a non-aqueous solvent such as acetone.
Mix for ~ 24 hours, spray granulate and shape.

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 in a predetermined amount with a binder, BN powder, and Mo powder with a non-aqueous solvent such as acetone for 12 to 24 hours, spray-granulated, and molded. Here, the Z value is set to 2.0 to 4.0 because when it is less than 2.0, the solid solution amount of Al ₂ O ₃ is small, and the property is close to that of Si ₃ N ₄ itself, and the corrosion resistance and the acid resistance are reduced. This is because the chemical resistance is insufficient, and when Z exceeds 4.0, the corrosion resistance and the like are improved, but the thermal shock resistance and the strength are deteriorated. 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. Mo amount is 1.0 to 10
Although the amount is made to be 10% by weight, if it is less than 1.0%, the effect of increasing the strength is not obtained, and if it exceeds 10%, the strength is greatly increased but the thermal shock resistance and the oxidative property are deteriorated, which is a problem in practical use.

[0008] For the molding, a uniaxial molding method or a hydrostatic molding method is usually used, 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.

[0009]

EXAMPLES Next, examples will be described. SIALON-B
As N-Mo quality, BN amount is 30% by weight and Mo amount is 5
% By weight, with chemical formula of SIALON: Si ₆ _zAlzOzN ₈ _
The Z value of z was 1.0 to 5.0, and the Z value of SIALON was 3.0 and the amount of Mo was 5
%, And the BN amount was changed from 0 to 60% by weight, and the SIALON Z value was 3.0 and the BN amount was 30.
A test body was prepared in which the amount of Mo was changed to 0 to 20% by weight. Next, each of the test pieces cut out to □ 20 × 250 mm was placed in magnesium melted at 1000 ° C.
After soaking for 0 hour, the amount of erosion loss, the amount of metal permeation, and the amount of oxidation loss were measured. The bending strength was measured according to JIS R1601. Regarding the amount of wear, a test piece of □ 60 × 20 mm was cut out and subjected to the following test method: An emery paper # 240 was attached to the outer peripheral surface of a rotating body having a diameter of 50 mm, and the test piece was pressed under a constant load to measure the amount of wear on the test piece. did. The rotation speed of the rotor was 60 rpm, the load was 50 kg, the slip distance was 2.0 m, and the rotor was cooled with water. The results are shown in Tables 1 to 4.

[0010]

[Table 1]

[0011]

[Table 2]

[0012]

[Table 3]

[0013]

[Table 4]

Next, SIALON-BN-Mo quality (Z =
3.0, BN = 30 wt%, Mo = 5 wt%) □ 2
A 0 × 250 mm test piece was prepared and an immersion test in a metal / flux was performed. As a condition, 2.0 kg of magnesium alloy and 500 g of flux are both melted in a # 20 crucible and held at 800 ° C. The test body is stirred for 15 minutes while being immersed in the molten metal, and is then allowed to cool from the molten metal for a maximum of 12 times. Repeat times. A similar test was conducted on a graphite test piece as a comparative material. The results are shown in Table 5.

[0015]

[Table 5] The test piece of the product of the present invention did not break even after repeating 12 times, and the amount of melting loss, permeation and oxidation was extremely small. The graphite of the comparative product was broken at the fifth time, and the penetration reached the surface.

[0016]

The SIA of the present invention is similar to the results of the above embodiment.
LON-BN-Mo quality shaft and stirring blade are made of Al,
Melt loss from non-ferrous metals such as Mg, Zn, Pb, and Sn, and alloys and fluxes of two or more non-ferrous metals,
There is almost no permeation and wear loss, and there are no handling problems. Therefore, maintenance-free operation is achieved by extending the life of the shaft and stirring blade, and non-ferrous metals such as Al, Mg, Zn, Pb, and Sn, and various non-ferrous metals of various types. It is possible to improve the quality of metal alloy products.

Claims (4)

[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 being IALON-BN-Mo 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. 4. The shaft for a non-ferrous metal melt degassing device and the stirring blade according to claim 1, wherein said Mo is 1.0 to 10 wt%.