JP2701297B2 - Method and apparatus for controlling semi-solidification of metal - Google Patents

Description

The present invention relates to a method and an apparatus for controlling a semi-solid state of a molten metal.

b. Conventional technology As a method for homogenizing alloys or refining crystal grains, a fixed rod is slid to the solidification interface near the mold of the molten material by rotating the mold to crush the generated crystals. Rotating mold scraper method to refine crystal grains, or scraper rotating solidification method to fix the mold, slide the rotating rod to the solidification interface near the mold of the molten material, and refine the crystal grains, solid-liquid coexistence state of the material , A rheocast method or the like is known in which a stirring rod inserted into the center portion is rotated to refine crystal grains.

Further, the molten metal is continuously cooled by the atmosphere, a cold cylinder, or the like, and a semi-solid state that appears during the cooling is captured, and low-speed stirring is performed.

c. Problems to be Solved by the Invention However, in these methods, there is entrainment of air at the time of rotational stirring, and therefore, in order to prevent such a phenomenon from occurring, the rotational speed is suppressed to a certain value or less. However, there has not been researched on the refinement of the crystal of the alloy at the time of stirring at an ultra-high speed with the rotation speed further increased.

Further, the semi-solidification method targeted by the present invention has not been established in terms of equipment, and the control of the semi-solidified state has not been performed.

d. Means for Solving the Problems The present invention has been made in view of the above circumstances, and relates to an apparatus for controlling a semi-solid state of a molten metal which solves the above problems.

That is, in the present invention, after melting a metal in a melting furnace, the melting furnace is moved to a control room, and in the control room, the molten metal is placed outside the melting furnace while applying rotary stirring in a vacuum. The temperature control is performed such that the molten metal is maintained in a semi-solid state by a heating means using a tungsten mesh heater provided inside and a cooling means comprising a water cooling cylinder provided independently outside the heating means. The present invention also includes a melting furnace provided with elevating means, and a control room for accommodating the ascending melting furnace, wherein the control room rotates and stirs the molten metal in the melting furnace. Means, a heating means provided by a tungsten mesh heater provided inside, a cooling means comprising a water cooling cylinder provided independently outside the melting furnace, and a temperature control means disposed outside the melting furnace. DOO is a semi-solidified controller metal characterized by.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a vacuum vessel provided with an opening / closing door at an appropriate position, 2 denotes an automatic opening / closing shutter for dividing the vacuum vessel 1 into upper and lower parts, 3 denotes a reflector, and the reflector 3 surrounds the reflector. To form a melting chamber 4. A control room 5 is provided above the shutter 2.

In the melting chamber 4, 7 is a crucible (melting furnace) for heating and melting the metal material, 8 is a heater (tungsten mesh heater) arranged around the crucible 7, and 9 is a temperature control inserted into the melting chamber 4. A thermocouple 11 is a support rod, and 12 is a pan (made of molybdenum) supported by the support rod 11. The pan 12 supports the crucible 7. Reference numeral 13 denotes a thermocouple for measuring temperature.

The support rod 11 is air-tightly held by a holding part 10 provided through the reflecting plate 3 of the melting chamber 4 and a holding part 14 provided through the lower part of the vacuum vessel 1. The bar 11 is configured to be able to move up and down.

In the control room 5, 16 is a rotor for stirring, 15 is a heater disposed around the rotor 16, 24 is a water-cooled cylinder further disposed on the outer periphery thereof, and 23 is a thermocouple.

The rotor 16 has a rotating shaft 17, and the rotating shaft 17 is airtightly and rotatably supported by a supporting device 18 provided on the upper portion of the vacuum vessel 1. Reference numeral 19 denotes a cooling water outflow / inflow passage provided in the support device 18 and is used for cooling the rotor 16. Reference numeral 20 denotes an observation window provided on the upper portion of the vacuum vessel 1, and the observation window 20 monitors the stirring state in the crucible by the rotor 16 and the state of the molten metal. 21 is a video camera, 23 is a thermocouple for controlling the temperature of the control room 5, and 24 is a water-cooled cylinder, in which cooling water flows.

In this apparatus, the vacuum vessel 1 is connected to a vacuum source (not shown), and after evacuation, a predetermined metal in the crucible 7 is melted by the heater 8 in the melting chamber 4.

Next, the shutter 2 above the melting chamber 4 is opened, and the crucible 7 is raised to a position shown by a two-dot chain line in the control chamber 5 via a support rod 11 by a crucible lifting mechanism (not shown).
As a result, the rotor 16 is inserted into the molten metal of the crucible 7, and the molten metal is rotated and stirred by the rotor 16. Also,
The molten metal is heated by the heater 15 to maintain the molten state. Further, the molten metal is cooled by the water cooling cylinder 24. Therefore, in order to maintain the semi-solid state of the molten metal in the crucible 7, the actual temperature in the crucible 7 is known by the thermocouple 23, and when the molten metal tends to shift from the semi-solid state to the solidification side, the heater 15 is operated. The temperature is raised to return to a semi-solid state. Also, when in the molten state, the heater
The operation of 15 may be stopped, the cooling by the water cooling cylinder 24 may be performed, and the transition to the semi-solid state may be controlled. During this time, the rotor 16 keeps stirring the molten metal, in a semi-solidified state, prevents the growth of metal crystals and refines the crystal grains, and, if necessary, adds nonmetal particles and short fibers to the molten metal. And uniformly dispersed.

If the predetermined quality is obtained, after stopping the heater 15,
The crucible 7 is lowered by the support rod 11 so that the rotor 16 and the molten metal can be separated, and the molten metal is solidified. In this case, a reducing, non-acidic or inert gas may be taken into the vacuum vessel and cooled.

Note that the cooling water flowing through the water cooling cylinder 24 can be replaced with a cooling medium such as another liquid or gas.

As a result of processing the hypereutectic aluminum-silicon alloy using the above-described apparatus, it was found that the primary crystal Si
The grain diameter is 1/10 to 1 /
The result was that the size was reduced to about 20.

e. Effects of the Invention As described above, according to the method and the apparatus of the present invention, the solid-liquid coexistence state (semi-solidified or semi-molten) of the alloy can be reliably captured, and thus the grain refinement can be effectively reduced. I can do it.
In addition, rotational stirring can be performed in the coexistence of solid and liquid, non-metal particles and short fibers can be uniformly dispersed, and a high-quality metal-based composite material can be manufactured.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory sectional view of a metal semi-solidification control device according to the present invention. 1 ... vacuum container, 5 ... control room, 7 ... crucible, 16 ... rotor.

Claims (2)

(57) [Claims] After melting a metal in a melting furnace, the melting furnace is moved to a control room, and the molten metal is provided inside the melting furnace while rotating and stirring the molten metal in the control room. Heating means by a tungsten mesh heater;
A method for controlling semi-solidification of a metal, wherein the temperature is controlled so as to maintain the molten metal in a semi-solid state by a cooling means comprising a water-cooling cylinder provided independently outside the metal. 2. A melting furnace provided with elevating means, and a control chamber for accommodating the ascending melting furnace, the control chamber comprising means for rotating and stirring the molten metal in the melting furnace, and a control chamber provided outside the melting furnace. Semi-solidification of metal characterized by comprising a heating means provided by a tungsten mesh heater provided on the inside, a cooling means comprising a water cooling cylinder provided independently on the outside thereof, and a temperature control means disposed. Control device.