JPS60127057A - Continuous casting device - Google Patents

Abstract

PURPOSE:To produce economically a casting having high quality with good workability by extending and projecting the top end of a casting mold sleeve into a melting crucible and heating said end with a molten metal in the crucible. CONSTITUTION:A casting mold sleeve 3 is embedded into the bottom of a crucible 2 so as to penetrate said part and the top end 3a of the sleeve is projected to extend for about suitable length into the crucible 2. Such top end is used as a pouring port 3'. A starting rod 7 is preliminarily inserted into the sleeve 3 and after the material to be melted in the crucible 2 is melted, pinch rolls 10 are pulled out to meet the solidifying rate of the molten metal A' in the top end 3a of the sleeve 3 by which a billet (a) is continuously cast. The billet which is free from solidification, breakdown, rough surface and flaw, has a smooth surface and does not contain oxide, etc. is obtd. until the top surface of the molten metal A arrives at the port 3' of the sleeve 3.

Description

[Detailed description of the invention] The present invention relates to improvements in continuous casting equipment.

Conventional continuous casting equipment connects a water-cooled mold to a heating melting furnace.
The molten metal (molten metal) melted in the melting crucible is directly spun into a water-cooled mold, cooled directly through the mold from the outside of the mold, and solidified.

However, the conventional device described above has the following drawbacks.

■ Impurities, oxides, and gas components present in the molten metal gather in the center of the billet (ingot) during the solidification stage, causing internal defects.

■Due to the large temperature difference between the outside and inside of the mold, the solidification of the molten metal becomes uneven, causing cracks and shrinkage pores.

■When pulling the billet out of the mold, there is always frictional resistance between the billet and the mold, which tends to cause rough skin, scratches, cracks, etc.

■Since the starting rod is cooled through the cooling mold, the pouring part solidifies and sticks due to heat conduction.
Initial withdrawals may not be possible.

In order to eliminate the above drawbacks, as shown in Figure 2, a heating element (9) made of an electrical conductor is installed around the mold sleeve (3) of the heating melting furnace (1) and around the bottom of the melting crucible 2).
An improved device provided with this is disclosed in Japanese Patent Application Laid-open No. 114446/1983.

However, in the above-mentioned improved device, it is necessary to separately equip the heating furnace with a heating element (9), which is not economical, and the lagoon 1 portion of the sleeve (3) is opened to the bottom of the crucible (2). Therefore, impurities flowing down along the crucible wall are likely to get mixed into the sleeve (3), and it is not always possible to expect an improvement in quality.

In view of the conventional circumstances, and in order to solve the problem, the present invention is made by projecting the upper end of the mold sleeve into the melting crucible by an appropriate length, and heating the projecting part by the temperature of the molten metal in the crucible. C1 The purpose of this invention is to provide an apparatus that can manufacture high-quality cast products economically and with good workability.

To explain the present invention with reference to the drawings, in FIG.
) is an induction heating melting furnace, (2) is a melting crucible, (3) is a mold sleeve, (4) is an induction coil, (5) is a water-cooled jacket 1~, (6) is a heat insulator, and (7) is a starting material. The rod, (A>) is the molten metal, and (a) is the billet (ingot).

The mold sleeve (3) is installed so as to pass through the bottom of the crucible (2), and its upper end (3a) protrudes into the crucible (2) by an appropriate length, and the upper end is connected to the pouring spout (3'). ).

Further, the mold sleeve (3) is inserted into a water-cooled di-V cut (5) so that it is cooled from the outer periphery by the jackets i to (5), and its lower end is used as an outlet (3'').

The lower structure of the crucible (2) may have an inclined surface as shown by the two-dot broken line in the figure, thereby reducing the amount of remaining molten metal.

A heat insulating material (6) is interposed between the melting crucible (2) and the water-cooled jacket h (5) to suppress heat conduction between the two.

The starting rod (7) is positioned in the cooling zone of the sleeve (3) at the beginning of casting (the position indicated by the two-dot broken line in the figure), and has the function of a plug for the sleeve (3). The tip of (7) has a shape that allows the solidified metal to be firmly held, and the other part is engaged with the pinch roll (10) so that it can be pulled out.

Therefore, the device of the present invention has the above-mentioned starting rod (7).
is inserted into the sleeve (3), and the induction coil (4) is inserted into the sleeve (3).
After the material to be melted in the crucible (2) is melted and tightened, the pinch roll (10) is pulled out at a rate that matches the solidification rate of the melt m (A') in the upper end of the sleeve (3a) to continuously form a billet. <a> can be cast.

The molten metal (A') in the sleeve upper end (3a) is heated by the molten metal 1 (A) in the crucible (2), and is sequentially cooled by being drawn out.

Next, examples will be shown.

The device is constructed by making the crucible (2) and sleeve (3) made of graphite, the water cooling jacket (5) made of copper, and the starting rod (7) made of mild steel.
(+) was melted in the crucible (2) and continuously cast.Also, the protruding length of the upper end (3') of the sleeve was 5Qn+m, and the height of the molten metal was 300mm>.

When the molten metal temperature reaches 680℃ at the center of the crucible (2),
When casting was carried out so that the cooling rate of the molten metal and the drawing speed of the billet were balanced, the upper surface of the molten metal (Δ) became the sleeve (3).
A billet 1~ was obtained which had a smooth surface without coagulation, breakage, roughness or scratches, and was free from contamination with oxides etc. until approximately reaching the pouring port (3').

Note that the billet drawing speed is set depending on the metal, the type of alloy, and the diameter of the billet.

According to the above device, the billet (a) has a diameter of lQmmφ
Casting of ~1501111+1φ was possible.

Further, in the case of a metal or alloy having a melting point of 1000° C. or less, it can be easily cast by electric resistance heating other than an induction heating furnace.

(Comparative Example) In the apparatus of the above embodiment, the pouring port 3' of the mold sleeve (3) is opened at the bottom of the crucible (2), that is, a device that prevents the upper end of the sleeve (3a) from protruding into the crucible. Alloy 10K (l) of Al-8i (1%) was prepared using
was melted and casting was started under the same temperature conditions as in the example.

As a result, the sleeve pouring port at the bottom of the crucible solidified and the billet could not be drawn out.

Therefore, in order to further increase the output of induction heating, raise the temperature of the molten metal, and raise the temperature near the sleeve pouring port to just above the melting point of Al-8i (1%) alloy, approximately 650℃, the temperature at the center of the crucible must be increased. There is no choice but to raise the temperature to 750°C to 800°C. If the billet is heated to a temperature much higher than the melting point and cast under unreasonable conditions, the billet will have rough surface texture, gas absorption and temperature differences between the inside and outside will cause Si segregation, and structural problems such as oxide entrainment will occur. Since the present invention is configured as described above, it has the following effects.

■ By heating and covering the upper end of the mold sleeve with the temperature of the molten metal, the temperature difference between the surface and the inside of the billet that comes into contact with the mold is small, so there is no segregation, and when the billet is pulled out of the mold sleeve, there is little frictional resistance, and the surface A smooth billet is obtained.

■Since the molten metal is injected while the injection port of the mold sleeve is always immersed in the molten metal, oxides are not involved, and metals and alloys can be cast at low temperatures just above their melting points. Gas absorption is also small, and therefore the degassing effect of the billet is large.

■Easy to control initial withdrawal using the starting rod and withdrawal due to changes in billet diameter.

■High quality is achieved as oxides, impurities, etc. that flow down to the bottom along the crucible wall do not enter through the sleeve pouring port.

■Since the humidity of the molten metal inside the crucible is used, there is no need to provide a separate heating element, making it economical.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the device of the present invention, and FIG. 2 is a sectional view of a known device. In the figure, (1) is the melting furnace, (2) is the melting crucible, (3) is the mold sleeve, and (3a) is the upper end of the sleeve (protruding part).
, (A) (A') is the molten metal, and <a> is the billet.

Claims (1)

[Claims] In a continuous casting device in which a mold sleeve is connected to a melting crucible of a heating melting furnace, the upper end of the mold sleeve is projected into the melting crucible by an appropriate length, and the projected portion is heated by the temperature of the molten metal in the crucible. Features continuous casting equipment.