SU1255844A1 - Method of producing metal in induction furnace having an additional electromagnet - Google Patents

Description

The invention relates to metallurgy to the technology of smelting metals and alloys, in particular aluminum, in an induction channel furnace with an additional electromagnet during its periodic operation.

The purpose of the invention is to simplify the process technology and improve the quality of the smelted metal by ensuring that gas porousness is closed in the metal crystallized in the channels by using hydrogen dissolved in the metal.

Example. After the NIN process of melting is carried out, the melt is poured to the induction channel furnace with an additional electromagnet, leaving part of the metal in the channels.

In the liquid metal coil induce electric current, compensating for heat loss. For this furnace, the heat loss is 12 kW, and the current compensating for this loss is 3.5 kA.

Before crystallization of the metal, its movement along the injection channel is blocked by introducing an electrically conductive plug into its mouth.

Electromagnetic systems are injected according to the injection circuit: the currents of the inductor coils are 100 and 110 A, and the electromagnet is 410 A. The voltages on the inductor coils are 32 V, on the electromagnet coil 52 V. In this mode, the metal flow through the delivery channel is zero, and the intensity of the vortices at the entrances to the active zone is maximum.

Within 10 minutes, degassing of the metal is carried out with an accumulation of hydrogen in excess of hydrogen.

After this time, the coil is crystallized, for which reason the voltage on the inductors is reduced to 21 V. The currents of the inductors are 60 and 63 A.

The crystallization process occurs directionally, first of all the swamp is frozen for two baths and then the alloy is in vertical channels.

The end of crystallization in vertical channels is determined, for example, by the temperature measured by a thermocouple on the wall of a vertical channel.

channel. In this case, this temperature is 230 C.

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five

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50

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five

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alloy crystallization in vertical channels 12-15 minutes, the current in the inductor circuit is 70 A.

For complete crystallization of the metal, inductors and an electromagnet are switched off. The hydrogen previously held in the vortex is distributed in the liquid metal at the site of the core and the lower part of the injection channel. The hard metal phase in the vertical channels prevents gas bubbles from floating up.

The concentration of hydrogen exceeds its solubility in a given volume of the alloy, and upon subsequent crystallization in the region of the active zone, a porous mass with closed pores is formed that does not shrink.

Since this concentration is achieved by degassing the metal in the channel portion of the furnace, and not by introducing an additional volume of hydrogen, the quality of the alloy does not deteriorate.

For a more uniform distribution of hydrogen after crystallization of the metal in the vertical channels before turning off the electromagnetic systems, for 2-3 minutes, the voltage pulse across the electromagnet is reversed. At the same time, by changing the direction of the electromagnetic force driving the metal, an intensive vibrating effect on the liquid phase of the metal in the active zone and averaging of the hydrogen concentration in the melt is provided.

The duration of the full cycle of metal crystallization is 30 minutes.

For the subsequent melting of the coil, inductor coils are connected to a voltage of 62 V (currents of 260, 280 A).

In the active zone, the induction current density is greater than in the other sections of the coil and, therefore, a greater amount of heat is absorbed. However, the low thermal conductivity of the porous metal in this area compensates for the increased heat generation, which ensures the uniform melting of the entire coil. The porosity of the metal also compensates for its thermal expansion during melting, which prevents the lining from cracking.

After the coil has melted, the hydrogen floats up, not dissolving again in the metal. This provides additional 3125584D4

alloy cleaning and improve furnace reliability by 20-30%

its quality. without removing molten from it

The technical advantages of metal sposo.

The ba is its simplicity - performance. The use of hydrogen, the pacTBQ method does not require additional srenno in the metal, to create a closure, and the possibility of wide-gas porosity on the site

application in industrial conditions of the active zone reduces by 1.5-1.8 times

Elimination of local overheating of the vit-number of non-metallic inclusions

ka when it is melted and prevented in the melt, which significantly increases

The destruction of the lining enhances its quality.

Claims (2)

1. METHOD FOR PRODUCING METAL IN AN INDUCTION CHANNEL FURNACE WITH AN ADDITIONAL ELECTROMAGNET, including melting, discharge of metal, crystallization of metal in channels with the creation of closed gas porosity in crystallized metal when the furnace is turned off, characterized in that, in order to simplify the process technology and improve metal, closed gas porosity is created by inducing a current that compensates for heat loss, blocking the movement of the metal along the discharge channel and turning on the electromagnet and an induction current decreases by 20-80%, and the furnace is carried off after crystallization. metal in vertical channels. 2. The method of pop. 1, characterized in that before turning off the furnace, the voltage on the electromagnet is pulsed reversed for 2-3 minutes. SU „1255844 ί