JPH11148929A - Apparatus for measuring inclusions in molten aluminum alloy - Google Patents

Abstract

(57) [Problem] To provide an apparatus capable of easily measuring the amount of inclusions in a molten aluminum alloy. The filter includes a cylindrical portion forming a cylindrical space, and a filter mounted on one end of the cylindrical portion. The filter is immersed in a predetermined depth of a molten metal made of a molten aluminum alloy. An apparatus for measuring the proportion of inclusions contained in the molten aluminum alloy by the amount of molten metal that passes through the filter within a predetermined time and is retained in the cylindrical space according to the head pressure of the molten metal. If there are many inclusions, the inclusions close the eyes of the filter and increase the flow resistance of the molten metal.
The amount of molten metal passing through the filter changes due to the passing resistance, and the amount of inclusions can be determined.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring solid inclusions such as metal oxides contained in a molten aluminum alloy.

[0002]

2. Description of the Related Art Solid fine inclusions such as alumina exist in a molten aluminum alloy. The fine inclusions are dispersed and held in the base material of the aluminum product obtained using the molten aluminum alloy as a raw material. The fine inclusions may be a point at which fine cracks occur, or may cause damage to the cutting edge during cutting. Thus, the amount of inclusions contained in the molten aluminum alloy is closely related to the quality of the resulting aluminum product.

[0003] Conventionally, as a device for measuring inclusions contained in a molten aluminum alloy, as schematically shown in FIG. 5, a filter container 102 having a filter 101 having a filter 101 at the bottom that allows the molten aluminum alloy to pass therethrough and no inclusions to pass therethrough. And a measuring vessel 103 for measuring the amount of the molten aluminum alloy that has passed through the filter 101. In this apparatus, inclusions in the molten aluminum alloy block the eyes of the filter 101 and reduce the amount of the molten aluminum alloy passing through the filter 101. Therefore, by measuring the amount of the molten aluminum alloy that has passed through the filter 101 with the measuring container, the amount of inclusions in the molten aluminum alloy can be measured.

[0004]

In this conventional apparatus, when the amount of the molten aluminum alloy injected into the filter container 102 varies, or when the temperature of the molten aluminum alloy changes, the molten aluminum alloy passing through the filter 101 is changed. The amount varies widely. Therefore, an operation and management such as injecting a predetermined amount of the molten aluminum alloy into the filter container 102 and maintaining the temperature of the molten aluminum alloy in the filter container 102 at a predetermined temperature are required.

An object of the present invention is to provide an apparatus which can more easily measure the amount of inclusions in a molten aluminum alloy.

[0006]

The inventor of the present invention presses the above-mentioned conventional filter container against the surface of a molten aluminum alloy melt, puts the molten aluminum alloy into the container from the outside of the filter container through a filter, and presses the inside of the container. The present invention has been completed by recognizing that the amount of inclusions can be determined by the amount of molten aluminum alloy contained in the alloy.

That is, the apparatus for measuring inclusions in a molten aluminum alloy according to the present invention comprises a cylindrical portion forming a cylindrical space and a filter mounted on one end of the cylindrical portion. One end of the molten aluminum alloy is immersed in a predetermined depth in the molten aluminum alloy, and is passed through the filter within a predetermined time by the pressure of the molten aluminum alloy corresponding to the depth and held in the cylindrical space. Is used to measure the proportion of inclusions contained in the molten aluminum alloy.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The apparatus for measuring inclusions in a molten aluminum alloy according to the present invention comprises a cylindrical portion forming a cylindrical space and a filter mounted on one end of the cylindrical portion. The cylindrical portion has a role of pushing the filter mounted at one end thereof to a predetermined depth of the molten aluminum alloy melt and a role of holding the molten aluminum alloy that has passed through the filter.

The pressure of the molten metal acting on the filter, that is, the head pressure of the molten metal, is proportional to the depth of the molten metal into which the filter has been pushed. In other words, the deeper the metal is pushed, the higher the pressure of the molten metal, and accordingly, the amount of the molten aluminum alloy that passes through the filter per unit time increases. In order to measure the amount of inclusions more accurately, the amount of the molten aluminum alloy passing through the filter also needs to be a certain amount or more. That is, the amount of the inclusion can be measured in a shorter time by pushing the filter deeper. For this reason, it is practically preferable that the cylindrical portion has a length of 10 to 50 cm.

The cylindrical internal space formed by the cylindrical portion serves as a holding space for the molten aluminum alloy passing through the filter, and the cross-sectional area of the internal space substantially defines the size of the filter. Considering these, the inner diameter of the cylindrical internal space is preferably about 2 to 5 cm. The filter blocks inclusions and passes only the molten aluminum alloy. Inclusions that have been blocked will block the eyes of the filter and block the passage of the molten aluminum alloy. Since the size of the inclusion is usually about 10 to 1000 μm, the size of the mesh of the filter is about 10 to 100 ppi (the number of meshes of 1 inch in length).
１０００1000 μm is preferred. It should be noted that a filter having a different mesh size can be employed as the filter depending on the size of the inclusions contained in the molten aluminum alloy.

The filter binds a number of particles to form pores in the gaps between the particles, or has a knitted fiber-like shape, a felt-like shape in which fibers are accumulated, or a sponge-like (foam) shape. However, it may have a large number of through holes in a honeycomb shape. The cylinder and the filter must be formed of a material that is stable at the temperature of the molten aluminum alloy and does not react with the molten aluminum alloy. From such a viewpoint, as the material of the cylindrical portion and the filter, alumina,
Ceramics such as silica and silicon nitride are preferred. In addition,
A metal coated with a ceramic that does not react with the molten aluminum alloy can be used as the cylindrical portion.

The apparatus for measuring inclusions in a molten aluminum alloy according to the present invention is characterized in that the end of a cylindrical portion provided with a filter is pressed into a molten metal of a molten aluminum alloy stored in a crucible or a ladle or the like to a predetermined depth. The state is maintained for a predetermined time, and thereafter, the metal is lifted from the molten metal, and the amount of the aluminum alloy contained in the cylindrical internal space of the cylindrical portion is measured to measure inclusions in the molten aluminum alloy. The amount of the aluminum alloy stored in the cylindrical internal space of the cylindrical portion can be easily measured by measuring the vertical distance of the internal space not filled with the aluminum alloy.

If the amount of inclusions in the molten aluminum alloy taken into the crucible is larger than a predetermined value and does not satisfy the predetermined quality, the molten aluminum alloy in the crucible is subjected to flux treatment or degassing by blowing an inert gas. By performing the gas treatment, inclusions in the molten aluminum alloy can be reduced. Thereby, a molten aluminum alloy of a predetermined quality can be easily obtained.

[0014]

The end of the measuring device of the present invention, which has a filter with a filter attached at one end, is inserted from the liquid surface of the molten aluminum alloy to hold the filter at a predetermined depth. As a result, the head pressure of the molten aluminum alloy corresponding to the depth of the filter acts on the outside of the filter.

Due to the head pressure, the molten aluminum alloy passes through the filter and enters the internal space of the cylindrical portion. The inclusions dispersed in the molten aluminum alloy entering the internal space are filtered by the filter, adhere to the surface of the filter, and close a part of the filter hole. For this reason, the passing speed of the molten aluminum alloy through the filter is reduced. In this way, the more molten aluminum passes through the filter,
Inclusions that become trapped in the filter also increase, and further block the pores of the filter, further reducing the rate of passage of the molten aluminum alloy through the filter.

The more inclusions in the molten aluminum alloy are captured by the filter, the greater the inclusions. That is, as the number of inclusions in the molten aluminum alloy increases, the passing speed of the molten aluminum alloy passing through the filter decreases. Therefore, if the filter is held at the same depth and for the same time, the more molten aluminum alloy that passes through the filter and is held in the internal space of the cylindrical portion,
The amount of inclusions contained in the molten aluminum alloy is small.

When a filter is held at a predetermined depth for a predetermined time, a calibration curve indicating the relationship between the amount of the molten aluminum alloy passing through the filter and the amount of inclusions contained in the molten aluminum alloy is prepared in advance. Thus, the amount of inclusions in the molten aluminum alloy can be known from the calibration curve by measuring the amount of the molten aluminum alloy passing through the filter, the amount of which is unknown.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail by showing an apparatus for measuring inclusions in a molten aluminum alloy according to an embodiment of the present invention. FIG. 1 shows a cross section of the inclusion measuring device of the present embodiment. The inclusion measuring device 1 includes a cylindrical portion 11 having a bottom end formed of an alumina fiber sleeve, and a filter 15 made of alumina ceramic foam disposed at the center of the bottom portion 12.

The cylindrical portion 11 has a length of 300 mm and an outer diameter of 4 mm.
It has a pipe shape of 0 mm and an inner diameter of 30 mm. A cylindrical inner space 13 having a constant diameter is formed at the center. The thickness of the bottom 12 is 10 mm. Filter 1
Reference numeral 5 denotes a short rod having an outer diameter of 10 mm and a height of 10 mm. The filter 15 is integrally fixed to the center of the bottom portion 12 of the tubular portion 11 as shown in a partially enlarged sectional view of the bottom portion 12 of the tubular portion 11 in FIG. The pore size of this filter 15 is 60 ppi (average pore diameter is 200 μm).

The apparatus 1 for measuring inclusions in a molten aluminum alloy according to the present embodiment has the above-described configuration. In addition, many measurement devices exactly the same as the inclusion measurement device 1 of this example were created. Next, using these inclusion measuring devices 1, FIG.
About 3 held by the graphite crucible 21 by the method shown in FIG.
The inclusions in the molten metal 22 of the 00 kg molten aluminum alloy were measured. As the molten aluminum alloy, a JIS standard AC4C aluminum alloy composition prepared from 50% of a virgin aluminum ingot and 50% of a recovered aluminum material was used. Note that the temperature of the molten metal is 7
30 ° C.

First, the bottom 12 of the inclusion measuring device 1 is measured.
Is placed in the molten metal 22 so that the flux floating on the liquid surface of the molten metal 22 does not adhere to the filter 15 on the bottom portion 12, and the filter 15 is held at a position at a depth of 200 mm from the liquid surface. This state was maintained for 3 minutes, after which the inclusion measuring device 1 was pulled out of the molten metal 22, and the height h of the aluminum alloy held in the internal space of the cylindrical portion 11 of the inclusion measuring device was measured. h was 5 cm.

The number of inclusions in the molten aluminum alloy constituting the molten metal 22 was determined by a dyeing method. The dyeing method is a method in which a molten metal is sampled in a predetermined mold, the surface is polished flat, and then a stain liquid is applied to a degreased, etched, and dried sample surface. The number of inclusions was 350 / dm ² . Next, the molten metal was subjected to flux treatment, and the height h of the aluminum alloy held in the internal space of the cylindrical portion was measured under the same conditions using a new inclusion measuring device. h was 13 cm. The amount of inclusions in the flux-treated aluminum alloy was 120 / dm ² .

Further, each molten metal was subjected to a degassing treatment by blowing a rotary inert gas. For this molten metal, the height h of the aluminum alloy held in the inner space of the cylindrical portion was measured under the same conditions using a new inclusion measuring device. h was 18 cm. The amount of inclusions in the degassed aluminum alloy was 35 / dm ² .
Table 1 summarizes the processing conditions of the molten metal, the height h of the aluminum alloy passed through the filter, and the amount of inclusions.

[0024] As is clear from Table 1, there is an inversely proportional relationship between the amount of inclusions in the molten aluminum alloy and the amount of aluminum passing therethrough.

For reference, FIG. 4 shows a calibration curve showing the relationship between the amount of inclusions in the molten aluminum alloy and the amount of aluminum passing through h. FIG. 4 also shows a calibration curve prepared by using the same filter as the inclusion detection device of the embodiment except for the size of the filter hole of the embodiment. 30 ppi, 60 ppi and 1 in FIG.
00 ppi indicates the pore size of the filter.

FIG. 4 shows that the size of the filter hole is 30 pp.
It can be seen that by using three types of inclusion detection devices i, 60 ppi and 100 ppi, the amount of inclusions in the molten aluminum alloy can be measured in the range of 1 to 1000 inclusions / dm ² in the molten aluminum alloy.

[0027]

By using the apparatus for measuring inclusions in a molten aluminum alloy according to the present invention, the filter is held at a predetermined depth for a predetermined time in the molten aluminum alloy to be measured for the amount of inclusions, and passed through the filter. The amount of inclusions can be easily measured by measuring the amount of the aluminum alloy. Since the device is extremely simple and easy to operate, it has high industrial utility value.

[Brief description of the drawings]

FIG. 1 is a sectional view of an inclusion detecting device according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a bottom portion of the inclusion detecting device shown in FIG.

FIG. 3 is a cross-sectional view schematically showing a state where measurement is performed using the inclusion measuring device of the embodiment.

FIG. 4 is a diagram showing a calibration curve showing a relationship between the amount of inclusions in a molten aluminum alloy and the amount of aluminum passing through h.

FIG. 5 is a diagram schematically illustrating a method of using a conventional inclusion measuring device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Inclusion measuring device 11 ... Cylindrical part 12 ... Bottom part
13 internal space 15 filter 21 graphite crucible 22 molten metal

Claims (4)

[Claims] 1. A cylindrical part forming a cylindrical space and a filter attached to one end of the cylindrical part, and one end of the cylindrical part having the filter is immersed to a predetermined depth in a molten aluminum alloy. Inclusions contained in the molten aluminum alloy according to the amount of the molten aluminum alloy retained in the cylindrical space through the filter within a predetermined time by the head pressure of the molten aluminum alloy corresponding to the depth thereof For measuring inclusions in molten aluminum alloy to measure the ratio of 2. The apparatus for measuring inclusions in a molten aluminum alloy according to claim 1, wherein the cylindrical portion and the filter are formed of a material that does not react with the molten aluminum alloy. 3. The apparatus for measuring inclusions in a molten aluminum alloy according to claim 2, wherein the material is alumina. 4. The apparatus for measuring inclusions in a molten aluminum alloy according to claim 1, wherein the filter has a porosity of 50% or more and a pore size of 10 to 100 ppi.