SU1265180A1

SU1265180A1 - Method of producing electrofused refractory material

Info

Publication number: SU1265180A1
Application number: SU853898241A
Authority: SU
Inventors: Ундасын Байкенович Ашимов; Юрий Альбертович Болотов; Юрий Григорьевич Черемисинов; Дамир Раисович Алимов
Original assignee: Алма-Атинский Энергетический Институт
Priority date: 1985-05-16
Filing date: 1985-05-16
Publication date: 1986-10-23

Abstract

Изобретение относитс к области производства огнеупоров. Целью изобретени вл етс снижение пористости материала. В предлагаемом способе получени электроплавленного огнеупора продувку расплава ведут после разливки его в инертным газом, нагретым до температуры 2300-2800 К с расходом 2,713 ,5 л/мин кг расплава в течение 5-15 мин. Полученные по данному способу материалы обладают более низкой пористостью The invention relates to the manufacture of refractories. The aim of the invention is to reduce the porosity of the material. In the proposed method of producing electrofused refractories, the melt is blown after casting it into an inert gas heated to a temperature of 2300-2800 K at a flow rate of 2.713.5 l / min kg of melt for 5-15 minutes. Obtained in this method, the materials have a lower porosity

Description

Изобретение относится к производству электроплавл^нных огнеупоров и может быть использовано в петрургии, огнеупорной промышленности»The invention relates to the production of electrofusion refractories and can be used in petrurgy, refractory industry

Цель изобретения - снижение пористости электроплавленного огнеупорного материала»The purpose of the invention is to reduce the porosity of electrofused refractory material "

Формирование структуры материала происходит на этапе охлаждения и кристаллизации расплава. При охлаждении газы, растворенные в расплаве при высоких температурах, выделяются образуя поры и усадочную раковину» Наибольшей растворимостью в оксидных расплавах обладают Н_?0, 0₂ и С0₇. Инертные газы в оксидных расплавах практически нерастворимы. При продувке инертного газа через расплав огнеупора парциальное давление газов, растворенных в расплаве, в пузырьке равно нулю, что создает градиент концентрации растворенных газов на границе расплав - объем пузырька инертного газа. Под влиянием этого градиента растворенные газы активно диффундируют в пузырек и происходит дегазация. Организация замкнутого цикла использования инертного газа позволяет избежать его потерь, и после очистки от Н_й0, С0₂,и 0„ он может быть снова использован ‘для продувки. Продувка газами, нагретыми до температуры 2300-2800 К, удлиняет время нахождения огнеупорного материала в жидком состоянии, интен<_ сифицирует перемешивание и, следовательно, дегазацию расплава, а также способствует разогреву формы в предкристаллизационный период, что улучшает структуру и физико-технические свойства отливки. Нагрев до температуры менее 2300 К не обеспечивает достаточного теплоподвода к расплаву, из-за чего быстро нарастающая вязкость последнего препятствует удалению газов» Отливки в этом случае имеют пористость выше 3%. Перегрев газа свыше 2800 К ведет к быстрому износу фурмы, уносу углерода и загрязнению им расплава. Про·· 'дувка газом с расходом менееThe formation of the material structure occurs at the stage of cooling and crystallization of the melt. Upon cooling, gases dissolved in the melt at high temperatures are released, forming pores and a shrink shell. The highest solubility in oxide melts is H _? 0, 0 ₂ and C0 ₇ . Inert gases in oxide melts are practically insoluble. When an inert gas is blown through the refractory melt, the partial pressure of the gases dissolved in the melt in the bubble is zero, which creates a gradient of the concentration of dissolved gases at the melt – volume of the inert gas bubble. Under the influence of this gradient, the dissolved gases actively diffuse into the bubble and degassing occurs. The organization of a closed cycle of using inert gas allows to avoid its losses, and after purification from Н _й 0, С0 ₂ , and 0 „it can be used again” for purging. Purging with gases heated to a temperature of 2300-2800 K lengthens the residence time of the refractory material in a liquid state, intensifies mixing and, therefore, degassing of the melt, and also contributes to the heating of the mold in the precrystallization period, which improves the structure and physicotechnical properties of the casting . Heating to a temperature of less than 2300 K does not provide sufficient heat supply to the melt, which is why the rapidly increasing viscosity of the latter prevents the removal of gases. Castings in this case have a porosity of more than 3%. Overheating of gas above 2800 K leads to rapid wear of the lance, carbon entrainment and pollution of the melt. Pro ·· 'gas blower with a flow rate of less

2,7 л/мин.кг не обеспечивает достаточно интенсивного перемешивания расплава и удаления газов. Увеличение расхода газа свыше 13”,5 л/мин»кг приводит к уносу расплава из формы и к непроизводительному расходу инертного газа, не приводящему к улучшению качества,материала,' дополнительному расходу энергии на его разогрев.2.7 l / min.kg does not provide sufficiently intensive mixing of the melt and the removal of gases. An increase in gas consumption above 13 ”, 5 l / min” kg leads to the ablation of the melt from the mold and to the unproductive consumption of inert gas, which does not lead to an improvement in the quality of the material, additional energy consumption for its heating.

Установлено, что продувка ме5 нее 5 мин не обеспечивает достаточной дегазации расплава, особенно из пристенных областей формы при центральном расположении фурмы. Продувка более 15 мин экономически нецелесо10 образна, так как при возрастании затрат на удлинение обработки качество материала улучшается незначительно. По предлагаемому способу проведены плавки корундового огнеупорного материала. Плавку ведут в трехфазной электродуговой печи мощностью 60 кВт в режиме открытой дуги при напряжении 80-120 В и токе 550-600 А. Расплав сливают в графитовые формы внутренним размером 280*130«130 мм с расположенной в дне формы фурмой диаметром 10 мм. Перед заливкой расплава включают подачу аргона с температурой 230Q-2800 К и расходом 2,725 13,5 л/мин.?кг. Нагрев газа осуществляют плазмогенератором мощностью 24 кВт. После окончания заливки расплава продувку осуществляют в течение 5-15 мин, после чего подачу га-.It was found that a purge of less than 5 min does not provide sufficient degassing of the melt, especially from the near-wall regions of the mold with a central location of the lance. Purging for more than 15 minutes is not economically feasible, since with an increase in the cost of lengthening the processing, the quality of the material improves slightly. The proposed method carried out the melting of corundum refractory material. Melting is carried out in a three-phase electric arc furnace with a capacity of 60 kW in an open arc mode at a voltage of 80-120 V and a current of 550-600 A. The melt is poured into graphite molds with an internal size of 280 * 130 "130 mm with a lance 10 mm in diameter located at the bottom of the mold. Before pouring the melt, an argon feed with a temperature of 230Q-2800 K and a flow rate of 2.725 13.5 l / min.? Kg is turned on. Gas heating is carried out by a 24 kW plasma generator. After pouring the melt, the purge is carried out for 5-15 minutes, after which the supply of gas.

за прекращают, фурму закрывают и охлаждают отливку в термоящике с диатомитовой засыпкой.per stop, the lance is closed and the casting is cooled in a thermobox with diatomite backfill.

Кроме того, были проведены срав- ^!нительные плавки с обработкой рас35 плава по известному режиму. Режимы продувки и характеристики изделий приведены в таблице.In addition, comparisons were made ^! body swimming trunks with melt processing according to the known regime. Purge modes and product characteristics are given in the table.

Как видно, из таблицы, материал с ’наименьшей пористостью получен при обработке расплава по предлагаемому режиму. Полученные по предлагаемому способу материалы обладают более низкой пористостью (1-2,5%) по сравнению с известным способом (3,0-5,0%) и могут применяться на ответственных участках футеровки металлургических агрегатов.As can be seen from the table, the material with the lowest porosity was obtained by processing the melt according to the proposed regime. Obtained by the proposed method, the materials have lower porosity (1-2.5%) compared with the known method (3.0-5.0%) and can be used in critical areas of the lining of metallurgical units.

Claims

G The invention relates to the production of electroplating refractories and can be used in petrology, refractory industry. The purpose of the invention is to reduce the porosity of the electrofused refractory material. The formation of the material structure occurs at the stage of cooling and crystallization of the melt. When cooled, gases dissolved in the melt at high temperatures are released forming a pore and shrinkage shell. N.O., 0, and CO have the highest solubility in oxide melts. Inert gases in oxide melts are practically insoluble. When an inert gas is blown through the refractory melt, the partial pressure of the gases dissolved in the melt in the bubble is zero, which creates a gradient in the concentration of dissolved gases at the melt boundary - the volume of the inert gas bubble. Under the influence of this gradient, the dissolved gases actively diffuse into the bubble and degassing occurs. The organization of a closed cycle of use of inert gas avoids its loss, and after purification from CO and 0 it can be used again for purging. Purging with gases heated to a temperature of 2300-2800 K, beats. ling time of the refractory material in the liquid state intensifies mixing and, consequently, degassing the stack, and also contributes to the heating of the mold during the pre-crystallization period, which improves the structure and physical and technical properties of the casting. Heating to a temperature of less than 2300 K does not provide sufficient heat supply to the melt, because of which the fast viscosity of the latter prevents the removal of gases. In this case, castings have porosity exceeding 3%. Overheating of gas at 2800 K leads to rapid wear of the tuyere, carbon carry-over and contamination of melt by it. Gas blowing with a flow rate of less than 2.7 l / min kg does not provide for sufficiently intensive melt mixing and gas removal. An increase in gas consumption of more than 13.5 l / min to leads to the carry-over of the melt from the molds and to the unproductive decomposition of the inert gas, which does not lead to an improvement in the quality of the material, an additional expenditure of energy for its heating. It has been established that purging less than 5 minutes does not provide sufficient degassing of the melt, especially from near-wall regions of the mold at the central location of the tuyere. Blowing more than 15 minutes is not economically feasible, since with an increase in the cost of lengthening the treatment, the quality of the material improves slightly. The proposed method held melting corundum refractory material. Melting is carried out in a 60 kW three-phase electric arc furnace in the open arc mode with a voltage of 80–120 V and a current of 550–600 A. The melt is poured into graphite forms with an internal size of 280 130 × 130 mm with a 10 mm diameter tuyere located at the bottom. Before pouring the melt, an argon supply with a temperature of 230Q-2800 K and a flow rate of 2.713.5 L / MIN.HKG is turned on. The gas is heated by a 24 kW plasma generator. After the end of the melt pouring, the purge is carried out for 5-15 minutes, after which the supply of gas is stopped, the lance is closed and the casting is cooled in a thermoelectric bed with diatomite. In addition, comparative melts with melt processing according to a known mode were carried out. Modes of purging and characteristics of the products shown in the table. As can be seen from the table, the material with the lowest porosity was obtained by treating the melt according to the proposed mode. The materials obtained by the proposed method have a lower yority (1-2.5%) as compared with the known method (3.0-5.0%) and can be used in the responsible sections of the metallurgy lining. chesky units. Claim Method The method for producing an electrofused refractory material includes melting the mixture in an electric arc furnace, blowing the melt with a heated inert gas, pouring the melt into molds and cooling, characterized in that

in order to reduce the porosity of the material, the melt is blown after casting it into the form with an inert gas,

1265180.4

heated to a temperature of 2300-2800 K with a flow rate of 2.7-TZ, 5 l / min., kg of melt for 5-15 minutes.

2.7

2300

Proposed

2.2-2.5 mode

1.3 Same 173, 0 Known mode with bath purging during the period of melting. The carbon inclusions content is 0.81, 2%; inclusions of metal recovered from the melt are observed (1%)