SU1502624A1 - Method of producing cast iron with globular graphite - Google Patents

Abstract

The invention relates to metallurgy and can be used in the production of castings from high-strength cast iron (chshG). The purpose of the invention is to reduce heat loss by melting iron, increasing its tensile strength and toughness. The proposed method includes pretreatment of molten iron with a ligature containing rare earth elements, and screening iron-silicon-magnesium ligature in one ladle, pouring the melt into the metal receiver in an amount equal to the metal intensity of the mold, equipped with a stopper, holding the melt for 10-15 s, removing the stopper , filling the cavity of the reaction chamber, and then the cavity of the mold. By a pretreatment in the ladle, using hearth and exposure to melt it before the mold inoculation, the method for preparing CHSHG provides increase _in σ in 1,06-1,08 times COP 1,02-1,2 times, as well as reducing heat loss 1.5-1.9 times. 1 tab.

Description

315

Thereafter, the metal is fed to the casting line and poured into the metal receiver of the mold. The metal receiver is made in the upper part of the mold and communicates with the gating system by means of a stand, which is blocked in the interface with the graphite stopper in the lower part of the metal receiver.

The metal is held in the metal receiver for 10-15 seconds. This metal extract in the metal receiver is necessary for slagging and floating up the unsuccessful reaction products of the interaction of a ligature containing rare earth elements and the sifting of the iron-magnesium-magnesium ligature with the molten iron, as well as ensuring minimal heat loss during processing.

The lower limit of IO is determined by the minimum time of coagulation of nonmetallic inclusions and their sputtering onto the surface, the upper limit is 15 s due to heat losses during settling in the metal receiver and stabilization of the removal of nonmetallic and slag inclusions.

 After the metal is aged in the metal reservoir, a stopper is removed and the reaction chamber is filled with melt and then the mold cavity.

The proposed technology provides: the ability to individually control the pouring temperature of each mold, eliminate local heating of the mold, prevent air oxygen from being captured when modifying inside the mold, minimal heat loss when filling the mold, eliminating water hammer during filling the mold, and stabilizing the casting duration.

The capacity of the metal reservoir is chosen equal to the metal intensity of the form, taking into account the metal intensity of the elements of the gating system and ensuring the maximum yield.

Primer p. Melting was carried out under production conditions by a duplex process cupola with acid lining with a capacity of 20 t / h - induction crucible mic

five

0

50

five

0

0

Carbon

Silicon

Manganese

Phosphorus

Sulfur

3.4-3.6

1.8-2.0

Up to 0.6

0.08-0.1

0.08-0.1

After overheating of the melt to 1460 ° C, the treatment was carried out according to the known and proposed methods for producing nodular cast iron taking into account the heat loss over time. As the representative of the most complex configuration, when modifying in the mold, a casting of the final gear housing was chosen, with which wedge-shaped samples were poured to determine the mechanical properties. The following refining and modifying additives were used: cerium mismetal (36% cerium), ligature (6-8% Mg).

The temperature of the metal in the mixer, as well as during the refining treatment in the ladles, was measured by a platinum-platinum-plating thermocouple immersion.

The results presented in the table indicate that the proposed method of obtaining chewing gland provides a higher level of Gg strength by 1.06-1.08 times, the impact toughness of CS by 1.02-1.2 times, as well as a decrease in heat loss by 1 , 5- I, 9 times.

Claims (1)

Invention Formula The method of producing nodular cast iron from cupola cast iron, including pretreatment with a ligature containing rare-earth elements, and sifting iron-silicon-magnesium ligature, as well as subsequent iron-silicon-ligature subsequent intraform processing, characterized in that, in order to reduce heat - loss of the molten iron, its tensile strength and toughness, its preliminary processing is carried out in one ladle, then a portion of the melt equal to the metal intensity of the mold, are pouring ser ICHTM-10. Correction of the chemical-55V metal receiver, equipped with a stop composition for the main components, is kept for 10-15 s, produced in a mixer. The chemical remove the stopper and fill the cast iron from the mixer, melt the reaction chamber, and then  the following limits, masd: and the cavity of the mold. 0.3% REM in dispensing bucket. 0.3% LCMG in casting ladle 80 530 370