Technical description of the AOD furnace process

AOD furnace method (argon-oxygen decarbonization method) is a more advanced technology for refining stainless steel. AOD furnace method has the advantages of simple equipment, convenient operation, strong adaptability, less investment and low production cost, and is widely used.

The molten alloy of the blast furnace and the intermediate frequency furnace is injected into the AOD furnace through the ladle, and O2, Ar or N2 mixed gas is blown during smelting to decarbonize the molten steel. At the same time, reducing agent, desulfurizer, ferroalloy or coolant are added to the feeding system to adjust the composition and temperature of the molten steel, and smelting qualified stainless steel water for continuous casting machine.

The delivery and regulation of mixed gas during refining is one of the main systems of argon oxygen furnace. The gas produced by the oxygen workshop is transported into the gas storage tank near the workshop through the pipeline, and after metering, decompression, adjustment and mixing, the mixed gas is sent into the furnace through the side gun according to the flow rate and ratio required by the process.

At the beginning of smelting, oxygen is decarbonized through a double-layer water cooling oxygen blowing pipe and blown into the metal melting tank at the top furnace mouth. For refining, use the mixed gas to send into the side gun into the furnace (installed on the side of the side wall near the bottom of the furnace). When loading and discharging the steel, the furnace body leans forward at a certain Angle, and the (side) tuyere is above the steel liquid level. When blowing normally, the tuyere sinks into the deep part of the dissolution tank. The central tube of the tuyere blows into the mixed gas of oxygen and argon or nitrogen, and adjusting the ratio of oxygen and argon can reduce the partial pressure of carbon monoxide to achieve the purpose of decarbonizing and preserving chromium. The type of AOD furnace tuyere is unique, it is a gas cooled consumption tuyere. The tuyere adopts a double casing structure, the outer pipe only through argon or nitrogen to cool the tuyere, the inner tube through oxygen and nitrogen, or argon mixed gas. Both the flow rate of the central pipe and the air mask ring can be controlled in the main control room.

Using the three-way side-gun technology. It can enhance the oxygen supply strength and improve the metal material yield, and this technology can shorten the AOD smelting time. Stable and reliable control system can reduce the consumption of gas and various refractory raw materials in smelting, and obtain stable product quality.

AOD Furnace Refractories