JPS61283451A - Dropping type casting device - Google Patents

Abstract

PURPOSE:To form a billet and ingot having fine crystal structure by dropping the molten metal in a tundish at specific periods from a nozzle, cooling the same with a gas from gas injection nozzles and introducing the liquid drops in a half-melted state into a casting mold. CONSTITUTION:The molten metal 11 in the tundish 12 passes plural pieces of holes 14 provided to a dispensing member 15 from a nozzle 13 and falls in the form of the liquid drops 19 when a stopper 16 is periodically moved up and down by a cylinder 17. The flatting liquid drops 19 are cooled by, for example, gaseous He, etc. ejected from the gas ejection nozzles 24 during the falling and fall in the half-melted state into the casting mold 18. The liquid drops are cooled by the casting mold 18 in the state in which the solid-liquid co-existence phase exists. The ingot 26 having the small crystal grain size of the solidified structure is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a dropping casting apparatus capable of producing ingots and slabs having a fine crystal structure.

[Prior Art] Generally, slabs or ingots, which are intermediate materials for gold products, are manufactured by pouring molten metal into a continuous casting mold or an ingot making mold and solidifying it.

However, in this technique, completely molten metal is cast, so the produced slab or ingot has a relatively large crystal grain size in its solidified structure. For this reason, when applying a reduction to a slab or the like to ensure mechanical properties, if a large reduction is applied, cracks will occur in the slab or the like. Therefore, it is necessary to apply the reduction blade in multiple steps, but this requires a long processing time and requires a large amount of thermal energy, resulting in high processing costs. The sensitivity to cracking due to the coarsening of the crystal grain size of the solidified structure is particularly noticeable in Ni-based ultra-super heat-resistant alloys, and the manufacturing process becomes extremely complicated when manufacturing this type of alloy. .

In order to eliminate these shortcomings in general casting technology, we have recently developed VAD E R (Vacuum ArcQou
ble Electrode Remelting
A casting technique called the vacuum arc two-electrode melting method has been proposed (Japanese Patent Application Laid-Open No. 165271/1983). This VA
In the DER method, as shown in FIG. 4, an arc 2 is formed between a pair of electrodes 1 made of a metal having the same composition as the ingot to be manufactured, and the opposing ends of the electrodes 1 are melted. This droplet 3 of molten metal falls into a mold 4, is cooled by the mold 4, and solidifies. Ingot 6 obtained by solidifying molten metal
is carried out from mold 4.

In this case, the droplet 3 of molten metal is slightly cooled in the process of falling from the electrode 1 into the mold 4 and becomes a semi-molten state. Therefore, the semi-molten metal 5 in the mold 4 solidifies in a state where the solid-liquid coexistence phase exists uniformly, so that the crystal grain size of the solidified structure of the ingot 6 is small. Therefore, even if a large reduction is applied, cracks will not occur in the ingot.

[Problems to be Solved by the Invention] However, in such conventional equipment, it is necessary to manufacture electrodes made of metal with the same composition as the ingot, and furthermore, it is necessary to manufacture an electrode made of metal with the same composition as the ingot, and it is necessary to produce an arc between a pair of electrodes. Therefore, there was a drawback that many steps and time were required to manufacture the ingot.

[Means for Solving the Problem] The present invention was made in view of the above circumstances, and it is possible to easily process ingots and slabs whose solidified structure has fine crystal grains without preparing electrodes in advance. The purpose of the present invention is to provide a dropping casting device that can be manufactured using suitable equipment.

The drip casting device according to the present invention includes a mold, a tundish containing molten metal, a nozzle provided on the bottom wall of the tundish, and a plurality of holes through which the molten metal in the tundish can flow out. a dispensing member disposed in the hole, and a heating means for heating the molten metal flowing through the hole;
It is characterized by comprising a cooling means for cooling the molten metal droplets dripping from the tundish by spraying gas on them.

In this case, the nozzle is preferably provided with a stopper for adjusting the opening area of the nozzle, and the nozzle is preferably opened and closed at an arbitrary period using this stopper.

[Embodiment 1] Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings. FIG. 1 shows a dropping casting apparatus according to an embodiment of the present invention. A nozzle 13 is fixed to the bottom wall of a tundish 12 that stores molten metal 11 with its axial direction perpendicular.

Inside the nozzle 13 is a cylindrical refractory dispensing member 1.
5 is inserted. As shown in an enlarged perspective view of FIG. 3, the dispensing member 15 is formed with a plurality of holes 14 extending in the axial direction. This hole 14 is about 10IIlO1
The hole 14 has a diameter of .phi., through which the molten metal flows out of the tundish 12. Nozzle 13
The dispensing member 15 and the dispensing member 15 may be integrated.

The stopper 16 is in the shape of a round bar made of refractory material, and is connected to the nozzle 13.
It is installed directly above, with its longitudinal direction vertical.

The stopper 16 is fixed to a piston of a cylinder 17 such as an air cylinder or a hydraulic cylinder, and moves up and down as the piston moves up and down with a pressure medium. Then, the upper end of the nozzle 13 is opened and closed by moving up and down at a predetermined period, and when the stopper 16 is raised by the cylinder 17, the nozzle 13 is opened;
When the nozzle 13 is lowered, the nozzle 13 is closed. A mold 18 is arranged below the nozzle 13.

Note that it is preferable that a heating source 23 such as a high-frequency induction heating coil be installed in the tundish 12 to prevent a drop in temperature of the molten metal during casting.

Further, a heating body 20 such as a high-frequency induction heating coil is embedded in the nozzle 13, and the dispensing member 15
By heating the molten metal passing through the hole 14, the molten metal is prevented from solidifying within the hole 14 and clogging the hole 14. The heating element 20 is not limited to a high-frequency induction heating coil, but as shown in FIG. 3, a resistance heating element 21 made of carbon, silicon carbide, or the like may also be used. In this case, the resistance heating element 21 is embedded in the nozzle 13, and the power source 22
The resistive heating element may be made to generate heat by supplying power from the resistive heating element. A gas jet nozzle 24 for spraying gas onto the droplets 19 of molten metal is installed below the nozzle 13, and the droplets 19 are cooled by spraying gas from the nozzle 24 onto the droplets 19. It has become.

Next, the operation of the dropping casting apparatus configured as described above will be explained. When the cylinder 17 moves the stopper 16 up and down and repeats the operation of opening the nozzle 13 for 0.3 seconds and then closing the nozzle 13 for 0.7 seconds, the molten metal 11 in the tundish 12 is separated from the nozzle 13. The liquid passes through a plurality of holes 14 provided in the pouring member 15, becomes a plurality of droplets 19, and drips into the mold 18.

While falling from this tundish 12 to the mold 18, the liquid 1ii19 is heated by a gas jet nozzle 24, for example, by H
It is cooled by being sprayed with e-gas, etc. Gas jet nozzle 2
The temperature of the droplet 19 can be freely controlled by changing the gas flow rate of the droplet 19. Similarly to the VADER method, the droplet 19 is slightly solidified and half-filled before it drops into the mold 18. Can be brought to a molten state. The semi-molten metal 25 in the mold 18 is cooled and solidified by the mold 18 in a state where a solid-liquid coexisting phase exists uniformly within the mold 18. Therefore, the crystal grain size of the solidified structure of the obtained ingot 26 is small.

Thereby, it is possible to produce an ingot having the same microstructure as an ingot produced using a conventional device using the VADER method.

The outflow of molten metal 1ii from tundish 12 is determined by changing the opening/closing time of stopper 16 and the diameter and number of holes 14 provided in dispensing member 15, assuming that the amount of molten metal 11 stored in tundish 12 is constant. This allows for free adjustment.

Further, as means for moving the stopper 16 up and down, various means can be used, not limited to the case where the cylinder 17 is used as in this embodiment.

Furthermore, continuous casting is possible by using a cylindrical mold and continuously pulling the slab obtained by solidifying the molten metal poured into the mold downward from the bottom of the mold.

[Effect of the invention]
I According to this invention, it is not necessary to previously manufacture electrodes made of metal of the same composition as the slab and ingot to be manufactured, and there is no need to generate an arc between the electrodes, resulting in a simple structure and an easy method. It is possible to produce slabs and ingots with fine crystal structures through operation, and is extremely practical.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing the implementation state of the present invention, Fig. 2 is an enlarged perspective view of the dispensing member, Fig. 3 is a schematic diagram showing a modification of the nozzle, and Fig. 4 is a schematic diagram showing a conventional device. be. 11; Molten metal, 12; Tundish, 13; Nozzle, 14; Hole, 15; Dispensing member, 16; Stopper, 17;
Cylinder, 1st: Mold, 19; Droplet, 20.23; High frequency heating coil, 21: Resistance heating element, 22; Power supply, 24;
Gas ejection nozzle, 25; semi-molten metal, 26; ingot. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 3 Figure 4

Claims (2)

[Claims] (1) A mold, a tundish containing molten metal,
A nozzle provided on the bottom wall of the tundish, a dispensing member disposed inside the nozzle having a plurality of holes through which the molten metal in the tundish can flow out, and heating the molten metal flowing through the holes. a heating means for cooling the molten metal droplets dripping from the tundish by spraying gas on the molten metal droplets;
A drip casting device characterized by having: (2) The drip type according to claim 1, wherein the nozzle is provided with a stopper for adjusting the opening area of the nozzle, and the stopper opens and closes the nozzle at an arbitrary cycle. Casting equipment.