Method for recycling RH vacuum tank cold steel by using high-temperature airflow

Abstract

The invention discloses a method for recycling RH vacuum tank cold steel by using high-temperature airflow. The method comprises the following steps of: in an LF refining process, blowing nitrogen toincrease the nitrogen content of molten steel after LF refining, and meanwhile increasing the Al content of the molten steel and increasing the temperature of the molten steel of LF refining tapping;and then performing RH vacuum treatment on the molten steel after LF refining by using driving gas. According to the method, nitrogen is increased for the molten steel in the refining process, a greatdeal of high-temperature airflow escapes from a vacuum tank in deep vacuum according to the characteristic that the gas is low in solubility under a deep vacuum condition, and the cold steel in the vacuum tank is scoured by using the airflow, so that the cold steel is recycled while the vacuum tank is cleaned.

Description

technical field [0001] The invention belongs to the technical field of steelmaking, and in particular relates to a method for reclaiming cold steel in a RH vacuum tank by using high-temperature air flow. Background technique [0002] RH system equipment is a secondary refining process equipment for molten steel used to produce high-quality steel. The whole molten steel metallurgical reaction is carried out in a vacuum tank with a refractory lining. The lower part of the vacuum tank is two dipping tubes with a refractory lining. Before the molten steel is treated, the dipping tubes are immersed in the ladle molten steel to be treated. When the vacuum tank is evacuated, the atmospheric pressure on the surface of the molten steel forces the molten steel to flow from the dip tube into the vacuum tank. The two dip tubes connected with the vacuum tank, one is the riser and the other is the downcomer. Since the rising pipe continuously blows argon gas into the molten steel, a rela...

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Problems solved by technology

This method of using gas to burn and melt the cold steel takes more than 1.5 hours at a time, and the waste slag basin needs to be hoisted independently to hold the cold steel, which affects the production rhythm, and because of strong oxidation, it cannot be recycled and causes waste

[0005] Chinese patent (application publication number: CN 110819768 A) discloses a method for improving the efficiency of RH vacuum grooved cold steel for low-carbon aluminum-killed steel, which utilizes low-carbon aluminum-killed steel to blow air with oxygen lance after RH treatment After burning and melting scrap steel, it directly uses treated molten steel for recycling. Its advantage is that it reduces the lifting of the waste slag basin for recycling, and greatly shortens the gas combustion time. Its disadvantage is that the oxygen content of the treated molten steel reaches more than 20ppm, which is not suitable for smelting special steel. universal adaptability

[0006] Chinese patent (application publication number: CN 110438299A) discloses a method for removing cold steel in RH vacuum tank. The core method is to process molten steel in the vacuum tank through high-temperature oxidation, and ensure that the liquid level of molten steel exceeds the position of cold steel slag by adjusting the flow rate of the driving gas. At the same time, carbon powder is added to react and heat up to achieve the purpose of high-temperature rinsing and cold steel removal. Compared with the traditional method, its advantage greatly shortens the washing time. The control needs to be more precise, and the operation is difficult. At the same time, the use of carbon-oxygen reaction to rinse the cold steel in the vacuum tank at high temperature will have a certain impact on the service life of the vacuum tank.

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