JPS58212846A - Casting method of al or al alloy - Google Patents

Abstract

PURPOSE:To cast Al (alloy) smoothly while removing the impurities in the molten Al (alloy), by removing mainly the oxide films among said impurities with a coarse meshed screen then removing mainly the fine pieces of refractories with a fine meshed screen and casting the Al (alloy). CONSTITUTION:Molten Al (alloy) M is passed through a relatively coarse meshed screen 4a by which mainly oxide films are removed therefrom. The fine pieces of the refractories passed through the screen 4a are removed with a fine meshed screen 4b. As a result, the oxide films and the fine pieces of the refractories are removed separately with the screens 4a, 4b meeting the respective sizes; therefore, the clogging in the screens is reduced considerably. The preferable opening size of the screen 4a in this case in a square shape of 3-10mm. length on one side or the equiv. area. On the other hand, the screen 4b having the opening size of about 3mm. length on one side or the equiv. area is used.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for balancing A/or A/alloys, in particular A/
Or A/It relates to a method for smoothly performing casting while efficiently removing oxide films and refractory particles mixed into the molten alloy.

Melting of A/or A/alloy C (hereinafter abbreviated as A/alloy)
During casting, impurities such as oxide films and refractory particles mixed into the molten metal during the melting and casting process can significantly reduce the quality of the cast product. A screen (usually around 1 an inch in mesh size)
A method of suppressing the entrainment of the impurities is carried out by removing the impurities tP through the molten metal and making the flow of the molten metal laminar. An example of this is the energization shown in FIG. A screen 4 with a mesh size of approximately 1+a+ is placed below the screen 4 to remove impurities such as those mentioned above, thereby increasing the cleanliness of the A/alloy molten metal M. However, for example, molten A' alloy with high Mg concentration (A/-4,5
When casting molten metal (Mg alloy, etc.), the screen 4 becomes clogged in a short period of time, and the passage resistance of the molten metal increases rapidly, reducing the pouring speed into the mold, or the molten metal level in the screen increases. rises and causes an overflow, making it difficult to continue casting work. In order to prevent such troubles, the screen 4 is usually vibrated to suppress clogging, but clogging cannot be prevented to this extent. Moreover, as the screen 4 is currently vibrated manually, the operation is complicated and dangerous, and furthermore, the vibration of the screen 4 can cause particles to slip through, resulting in frequent linear defects in the final product. Quality issues have also been pointed out.

The present inventors took advantage of the above-mentioned circumstances and efficiently removed impurities in the A/alloy f4 vortex without causing the above-mentioned problems.
Intensive research has been carried out to establish a method that can remove it. The present invention was completed as a result of such research, and consists of a method for removing impurities in the bath using a screen when casting is performed using molten metal A/or A/alloy. , according to the first screen
The gist lies in primarily removing the oxide film and then using a fine screen to primarily remove the refractory debris.

In order to suppress screen clogging, the present inventors first conducted a study to clarify the form of impurities that cause clogging.3 As a result, the impurities contained in the A/gold alloy are: The majority of these are oxide films that are formed through air oxidation during the melting and pouring stages, and refractory fragments that fall off from the inner walls of tundishes, etc., and the former are formed as linear or band-like objects. However, it was confirmed that the latter was mixed in as fine particles. Therefore, when removing these, linear or band-shaped oxide films are attached to the screen 4 in a tangled state, making the mesh even finer, and fine particles on the screen are attached, so that clogging is prevented. Progress rapidly.

Based on this, I think that clogging can be suppressed as much as possible by adjusting the size of the oxide film and the granular refractory pieces and adding them using separate screens. reached. The present invention utilizes the above-mentioned idea for cleaning molten metal. It passes through a screen 4a to mainly remove the oxide film, and then the refractory pieces that have passed through the screen 4a are removed through a fine screen 4bKi. That is, with this method,
Since the oxide film and the refractory debris are removed separately by the screens 4a and 4b, which are appropriate for their respective sizes-75), the clogging of the screens is drastically reduced.

As mentioned above, the mesh and screen 4a used in the present invention should be selected to mainly remove oxides and allow the refractory pieces to pass through, and as a result of experiments, the mesh size should be such that one side of the screen has no erosion. It has been found that a grid of 8 to 10 items or an area corresponding to this is preferable. However, if the mesh size of the lever is too small, although the oxide film itself is removed efficiently, the refractory strips are also added at the same time by the aforementioned mechanical lance, so that the screen 48 portion becomes less likely to be clogged.

On the other hand, if the mesh size is too large, the addend effect of the oxide film becomes insufficient and a large amount of oxide film oozes out in the direction of the screen 4b, resulting in significant clogging in the screen 4b portion.

In addition, the fine screen 4b must be able to almost completely remove the refractory '1orltB pieces, etc. that passed through the screen 4a as the final overlay material, and for this purpose, the mesh size should be 1 side. It is necessary to use a mesh with a length of at most 8 mm or an area equivalent to that.9 However, if the mesh size is too small, the surface tension of the molten metal will prevent it from starting to pass through the screen. At the same time, the passing speed of the molten metal decreases, so 0. Fl
l! II! It is desirable to use a square grid size or larger.

The preferred size of the M meshes of the screen 4b is about 1 to 2 angles.

Incidentally, Table 1 shows the results of examining the permeability of molten metal and the degree of cleanliness of the obtained ingot when the mesh size of the screen 4b was kept constant at 1 mm angle and the mesh size of the screen 4a was variously changed. 1. The experimental conditions were as follows, and the experiment was carried out according to the method shown in FIG.

[Experimental conditions] Bath type: A1 alloy 5182 Refined blacks, KCr-based molten metal Humidity near 80°C Screen material: Nigels wool The effective surface area of each screen was constant regardless of the mesh size of the screen.

The maximum mesh size is 8 to 10 mm square.

The present invention is roughly constructed as described above, and is an extremely simple $71 process in which molten At alloy is first passed through a burnt screen trap and then passed through a fine screen, thereby minimizing clogging of the screen. It is possible to efficiently remove impurities, mainly oxide films and refractory particles, while preventing them.As a result, the speed at which the molten metal passes through the screen increases, and the frequency of interruptions in casting operations due to clogging is drastically reduced, resulting in a clean It is now possible to manufacture high-strength At alloy castings with high productivity.Also, abnormal rises in the molten metal level due to clogging hardly occur, so it is easy to control the process of continuous casting. It also makes it easier to manage patchy structures and is extremely useful in automating the balancing process.

[Brief explanation of the drawing]

Figure 1 shows a schematic longitudinal cross-sectional explanation of the conventional stirrup torture method.
The figure is a schematic longitudinal IIr plane explanatory diagram showing an embodiment of the present invention. l...Pouring nozzle 2...Distributor 8...Mold 4.4aJ4b...Screen M...
At or At alloy bath water applicant Kobe Steel, Ltd.

Claims (1)

[Claims] +1) When performing casting using A/ or AI alloy molten metal, impurities in the f@ leaked metal are removed using a screen, first of all, the oxide film is mainly removed using a coarse screen, A method for casting A/or A/alloys, characterized in that the refractory particles are then removed through a fine screen.