SU865512A1 - Method of treating molten iron - Google Patents

Description

(54) METHOD FOR TREATING LIQUID CHUGON

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The invention relates to foundry, in particular to the production of modified or alloyed cast iron, and can be used in machine-building enterprises in the production of castings from modified or alloyed cast iron.

It is known that the treatment of liquid iron with various modifiers or alloying additives improves the structure of the iron, affects the shape of graphite and improves the mechanical properties.

A method of producing high-quality cast iron is known, in which a modifier or alloying agents are introduced into a ladle with liquid iron and subjected to vibration treatment and induction heating. This method improves the effect of the modifier or alloying agent on molten iron and, as a result, improves the quality of the iron 1.

The disadvantage of this method is the effect on the modifier or alloying additive of the oscillatory process only with a limited frequency limit arising from the vibration of the bucket, which slightly increases the absorption coefficient of the modifier or alloying additives and does not sufficiently increase the mechanical strength of the iron.

The closest to the proposed technical essence and the achieved result is a method for producing castings, which includes treating modified cast iron poured into a mold by imposing an electromagnetic field on the melt and passing an electric current through it.

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The disadvantage of the method is that a high level of assimilation of the reactants and the necessary level of the mechanical properties of the iron are not achieved.

The purpose of the invention is to increase the degree of assimilation of reagents and increase the mechanical properties of cast iron.

This goal is achieved due to the fact that in the known method of processing liquid iron, including the introduction of modifiers or ligatures into it, the imposition of an electromagnetic field on a melt and the passage of electric current, a pulsating current with a pulsation coefficient of 0.004-1.5 is passed through the melt.

The electromagnetic field is applied with a frequency of 6-15 Hz and a intensity of 1.5-2 X.

Favorable conditions for the assimilation and action of a modifier or alloying additives on liquid iron are created by the excitation of oscillations by a pulsating current due to the acceleration of diffusion processes in microvolumes, increased carbon activity in local melt zones, changes in surface tension forces at the solid and liquid melt phase, improving conditions ion interactions. These factors affect the process of crystallization of iron, making its structure more fine-grained and, consequently, increasing the mechanical properties. Example 1. Liquid iron produced from a cupola or other smelting furnace is fed into a transfer vessel or into a ladle with a modifier or alloying additive placed either on the furnace channel or directly in the transfer vessel. Electrodes are inserted into the transfer tank or in the ladle, through which a pulsating current is applied. The current was processed for 2–3 min with a current of 2.5 A voltage of 30 V, with & pulsations 1,5. After exposure to the current, the cast iron is directed to the pouring.

The experimental setup allows pulsating (with a pulsation coefficient of 0.004-1.5) to be treated with liquid iron during the modification or alloying process.

When treated with an electric current with a voltage of 30 V, a force of 2.5 A and a ripple factor of 1.5, the tensile strength of the iron increases by grade with a slight increase in hardness. Flexural strength increased to 54 kgf / mm.

Example 2. Liquid iron produced from a cupola or other smelting furnace is fed into a transfer tank along with a modifier or alloying agent.

prisazhivaemaya or on the chute ne and directly into the transitional tank. The transient capacitor is equipped with an electromagnet creating a low-frequency magnetic field, and electrodes along which a pulsating current flows. The mixture of liquid iron with a modifier or alloying agent is simultaneously affected by an electromagnetic field of a partial 15-6 Hz, with a nominal value of 1, and an electrical current of 30 V, at a current of 2.5 A for 2-3 minutes. Increased flexural strength.

The liquid iron treated in this way with the additive of the modifier mill JK with a doping additive improves the mechanical properties of the iron, increases the time of action of the modifier and increases the rate of absorption of the modifier or. alloying additive.

Claims (2)

1. A method for treating molten iron, J including the introduction of modifiers into it or ligatures, the imposition of an electromagnetic field on the melt and the transmission of electric current, characterized in that, in order to increase the degree of assimilation of the reactants, to increase the mechanical properties of the iron, a pulsating current with a pulsation coefficient of 0.004-1.5 is passed through the melt. 2. A method according to claim 1, characterized in that the electromagnetic field is applied with a frequency of 15-15 Hz and an intensity of 1.5-2. Sources of information taken into account in the examination 1. The patent of Germany No. 1267238, cl. From 21 to 1/00, 1956. 2. The author's certificate of the USSR. № 483190, cl. B 22 D 27/02, 1973.