Insert tube for vacuum circulating degassing furnace and manufacturing method of insert tube

Abstract

The invention relates to an insert tube for a vacuum circulating degassing furnace and a manufacturing method of the insert tube, and belongs to the field of external refining in metallurgical production. The insert tube for the vacuum circulating degassing furnace comprises a barrel-shaped steel structure, refractory bricks and a poured layer, wherein the refractory bricks are laid on the inner wall of the steel structure, and the poured layer is formed on the outer wall of the steel structure. The poured layer comprises a lower poured layer body and an upper poured layer body, wherein the upper poured layer body makes contact with the lower poured layer body. The upper poured layer body makes contact with slag when vacuum circulating degassing refining is carried out, the lower poured layer body makes contact with molten steel when vacuum circulating degassing refining is carried out, and the outer diameter of the lower poured layer body is smaller than that of the upper poured layer body so that a T-shaped structure can be formed. The insert tube of the T-shaped structure eliminates bonded slag of castable making contact with the molten steel, the amount of slag needing to be removed is reduced, slag removal time is greatly shortened, temperature drop is reduced, the gunning effect is improved, and the service life is prolonged (the insert tube can be used more than 90 times).

Description

technical field [0001] The invention relates to an insertion tube for a vacuum circulation degassing furnace and a preparation method thereof, belonging to the field of out-of-furnace refining in metallurgical production. Background technique [0002] In 1957, German Thyssen Steel Company invented the vacuum cycle degassing-RH method. In the 1970s and 1980s, Japan successively developed the RH-OB method, RH-KTB method and RH-PB method, and continuously improved the refining of RH. Function. As the market has higher and higher requirements for the cleanliness of steel and the demand for high-quality steel increases, most steel mills at home and abroad have been equipped with RH refining devices. During the refining process, the outer castable of the RH insertion tube is prone to melting loss and peeling due to the erosion of high-temperature molten steel, erosion of molten slag, and thermal shock of rapid cooling and rapid heating. Moreover, after the RH treatment, the slag...

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Problems solved by technology

Patent CN201110441219.1 introduces dense corundum, and develops a cement-free RH vacuum furnace insert tube corundum castable, with a service life of about 80 times, and the cost is increased compared with existing castables

[0004] In addition, during the RH treatment process, the castables in contact with the slag are prone to erosion or sticky slag. At present, the methods to reduce the sticky slag mainly include 1. Coating treatment (patent CN200610018622), specifically the use of coating to prevent the slag from Direct contact with castables achieves the purpose of reducing sticky slag, but during the process, the erosion of the coating by slag limits its ability to inhibit sticky slag

2. Slag adjustment treatment (patent CN101307375), is to modify the slag in the later stage of RH treatment to reduce the viscosity of the slag, so that the slag is not easy to adhere to the insertion pipe, but it will cause erosion of the castable and ladle lining exacerbated

The method of removing sticky slag on the insertion pipe mainly uses a mechanical scraper (patent CN200620098887.3, patent CN200820076256.0, etc.), but due to the existence of cold steel in the sticky slag, mechanical cleaning is easy to damage the castable, and the processing time is long. The large temperature drop will affect the gunning effect and greatly reduce the service life

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