What is open hearth steel?

Open hearth steel refers to the carbon steel and ordinary low alloy steel smelted by open hearth, which can be divided into acid open hearth steel and basic open hearth steel according to the properties of lining materials. Process of treating molten steel with argon in open hearth furnace. Tests were carried out in open stoves with capacities of 150, 300 and 430t. The steel is smelted by scrap - ore process according to the current process. Metal Ar is blown through the inclined oxygen gun on the furnace top, and the gas consumption is 400 ~ 1200m /(h· gun). YKOC-1 sensor was used to check the oxygen activity in melt before and after injection. In the smelting group, metal and slag samples are selected from the furnace.

Principle of open hearth steel

The hearth of an open hearth is a trough of firebrick covered by a roof of firebrick. There is a charging port on the front wall of the open hearth, from which the charging machine will load the charge. Close the door made by the firebrick during smelting. Both ends of the furnace are built with a furnace head, each head has two holes for the introduction of fuel and hot air, or from the furnace gas.

The raw materials used in open-hearth steelmaking are scrap steel, scrap iron, iron ore and solvents (limestone and quicklime). At the beginning of smelting, the fuel meets the hot air imported and burns on the fuel surface at a temperature of up to 1800℃. The heat is transferred directly from the flame to the charge, making the charge melt rapidly (the melting point of iron is 1535℃, steel is slightly lower). At the same time, a part of the molten pig iron is formed into ferrous oxide. The impurities in the pig iron, silicon and manganese, are oxidized by ferrous oxide and generate slag. Because there is too much limestone in the furnace, impurities such as phosphorus and sulfur form calcium phosphate and calcium sulfide into slag. Second, the carbon is oxidized, producing carbon monoxide that rises from the molten metal as if it were boiling.

When the reaction is about to finish, add the deoxidizer and periodically pull out the slag. The composition of the steel is checked according to the pre-furnace analysis (which can be done in a few minutes by rapid analysis) when the smelting is about to be completed. The resulting steel flows from the outlet into the ladle, from which it is poured into a mold to form a product or ingot.

In order to raise the furnace temperature, the gas fuel must be preheated in the regenerator chamber.

Not only liquid pig iron, but also solid pig iron, waste iron and iron ore after processing can be added in the open furnace. In addition, if 30% oxygen-rich air is used in an open furnace and oxygen is blown into the molten metal at the same time, the productivity can be increased by 80%, the smelting time can be shortened by two to four hours, and fuel can be saved. The oxygen-rich air does not need to be preheated