JPS6141661B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a continuous casting method in which improvements are made to the casting method and towing method for obtaining a sound ingot in, for example, horizontal continuous casting. Conventionally, there has been an apparatus shown in FIG. 1 for carrying out continuous casting. In the figure, 1 is a heat retention furnace, 6 is a mold, 2 is a cooling device for the mold, 3 is a traction device, and 4
is a traction roll that is driven intermittently by electric signals,
Reference numeral 5 denotes a presser roll that presses down the ingot and the traction roll 4 using hydraulic pressure and accurately transmits the traction drive force to the ingot. Next, the operation will be explained. Tow roll 4
functions to transmit forward rotation, stop, reverse rotation, and stop operations to the ingot pulled out together with the presser roll 5 by programmed intermittent electric signals. Through this operation, the molten metal in the insulating furnace 1 is transferred to the cooling device 2 of the mold 6.
Inside, it solidifies when stopped and is continuously cast while being towed during normal rotation. The reversal of the traction roll is transmitted to the ingot 10, and the ingot 1
Since the 0 moves in the opposite direction to the drawing direction, it is sometimes used for the purpose of removing evaporated metal, impurities, reversely segregated metal, etc. attached to the surface of the ingot from the surface of the mold 6 in the cooling device 2. In the conventional intermittent traction system, as shown in Figure 3, which shows an example of phosphor bronze for springs, there are ) have different organizations. Furthermore, although not shown in the photograph, reverse segregation metals and metals with high solute concentration exist at the grain boundaries in the stop portion. Furthermore, dissolved gas that cannot escape tends to remain at the end of normal rotation drive. Metal and gas remaining at these grain boundaries cause cracks or scratches during subsequent processing. As described above, in conventional intermittent casting, it is difficult to obtain a sound ingot, and the quality is unstable. This invention was made in order to eliminate the drawbacks of the conventional system as described above. In other words, this invention creates a uniform fine structure, a structure with little segregation, and
Another object of the present invention is to provide a continuous casting method characterized by a casting traction system, which can produce a healthy ingot that facilitates the escape of dissolved gases. FIG. 2, which shows an embodiment of the present invention, will be explained. 1 is a heat retention furnace, 2 is a mold cooling device, 3 is a traction device, 4 is a traction roll, 5 is a presser roll,
6 is a mold, 7 is a swinging device that slightly vibrates the ingot in parallel with the drawing axis of the ingot using a traction device 3 consisting of a traction roll 4 and a presser roll 5, and an eccentric cam 8 that generates the amplitude of reciprocating motion. It consists of a power source 9 such as a motor and hydraulic pressure that generate vibrations. As the eccentric cam 8 rotates, the entire traction device 3 repeats minute vibrations with a constant amplitude and frequency. Furthermore, by continuously rotating the towing roll 4 in a constant normal direction, the ingot 10 is immediately pulled forward while being slightly vibrated. The condition of the casting surface, the condition of the casting surface of the castings cast by the conventional method and the method of this invention under several different conditions.
The workability, soundness, and life of the mold were investigated, and the results shown in the table below were obtained. In both cases, the draw casting speed was 130 mm/min.

[Table] As can be seen from the above table, when the method of the present invention is used, the life of the mold is slightly worse, especially when the vibration frequency is increased, but the cast structure is superior. FIG. 4 shows an example of a structure cast by the continuous casting method according to the present invention. FIG. 4 shows #7 in the above table, and it can be seen that it has a uniform and fine structure. Incidentally, FIG. 3 shown as a conventional example shows #10 in the above table. According to this invention, micro-vibrations applied to the solidification interface by directly shaking the ingot cut the tips of dendrites that try to grow in the direction of heat flow, thereby increasing the size of crystal nuclei and making them uniform. becomes a fine structure.
The uniform and fine structure eliminates distortion during uneven casting, making it less likely to crack during subsequent processing. Furthermore, the microvibration at the solidification interface has the effect of escaping and releasing the dissolved gas trapped between the secondary arms of the dendrites. After the ingot with little dissolved gas is stretched,
Fewer scratches such as blowholes occur. Furthermore, the micro-vibration at the solidification interface has the same effect as the reverse rotation drive during intermittent casting, and has the effect of removing deposits on the surface of the ingot. In vertical continuous casting, there is a conventional method in which the mold is vibrated up and down while continuously drawing out the ingot. Even with this method, it is difficult to obtain stable quality because the ingot itself cannot be vibrated. As described above, according to the present invention, casting is performed while slightly vibrating the solidification interface by applying minute vibrations in the same direction as the drawing axis of the ingot, resulting in a uniform fine structure, reverse segregation, and dissolved gas. This has the effect of obtaining a healthy ingot by preventing the remaining of.

[Brief explanation of the drawing]

Fig. 1 is a layout diagram schematically showing a conventional horizontal continuous casting device, Fig. 2 is a layout diagram schematically showing a horizontal continuous casting device for carrying out the present invention, and Fig. 3 is a layout diagram showing an outline of a horizontal continuous casting device for carrying out the present invention. FIG. 4 is a 10 times enlarged micrograph showing the structure of a cut surface along the casting direction, and is a photo similar to FIG. 3 showing an ingot produced by the method of the present invention. In the figure, 1 is a heat retention furnace, 2 is a mold cooling device, 3 is a traction device, 6 is a mold, and 7 is a swing device.

Claims (1)

[Claims] 1. A traction device that makes reciprocating motion in a direction parallel to the drawing axis of the ingot by bringing a presser roll into contact with the upper surface of the ingot and a traction roll into contact with the lower surface of the ingot being pulled out horizontally from the ingot through the mold from the heat-retaining furnace in the above-mentioned direction. A continuous casting method characterized in that casting is performed while slightly vibrating the solidification interface of the ingot by applying a slight vibration in the same direction as the ingot.