Method for adding rare earth into RH refining furnace

Abstract

The invention relates to a method for adding rare earth into RH refining furnace. The method is characterized in that rare earth lanthanum ferroalloy is added into a RH refining station vacuum feeding bin; molten steel, which satisfies the condition that total oxygen content T.O is less than or equal to 0.002 wt%, active oxygen content a [O] is less than or equal to 0.0005 wt% and [S] content is less than or equal to 0.005 wt% in steel, undergoes vacuum treatment at the RH refining station for 10 min or more than 10 min; and according to the calculated addition of rare earth, rare earth lanthanum ferroalloy is added into a vacuum chamber from the vacuum feeding bin, wherein the addition of the rare earth is controlled within the range of 0.005-0.015 wt%. The invention has the following advantages: by the adoption of the method, the yielding rate of rare earth is high and stable; continuous casting production is smooth; rare earth in steel is uniformly distributed; by the adoption of the rare earth lanthanum ferroalloy, performance of steel is substantially improved; the method requires low cost and is simple to operate; metallurgical effects of rare earth microalloyed steel are obvious; and the method has an extensive popularization and application prospect.

Description

technical field [0001] The invention relates to a method for adding rare earth to steel, in particular to a method for adding rare earth to an RH refining furnace, and belongs to the field of iron and steel metallurgy. Background technique [0002] my country is the largest rare earth country in terms of rare earth resources and production in the world, and also the largest steel production country. However, there is still a considerable gap between the quality of steel products and the advanced level of foreign countries, and a considerable amount of steel products still need to be imported. From the 1960s to the present, the research and production of rare earth steel in my country has a history of 50 years. At present, the domestic rare earth steel is troubled by the development of continuous casting process and the addition process, and the variety and output of rare earth steel are limited. [0003] In recent years, in order to meet the demand for rare earth metal neody...

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Problems solved by technology

[0007] So far, there is no suitable rare earth addition method that can meet the requirements of rare earth steel production. This problem has been perplexing metallurgists.

[0011] Before and after LF refining, and before and after VD vacuum, the mixed rare earth cored wire is fed in the ladle. The recovery rate of rare earth in the steel is extremely low, and the rare earth basically exists in the steel in the form of inclusions, and the metallurgical effect is not good.

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