Steel casting smelting method to control nb content

Abstract

The invention relates to a steel casting smelting method capable of controlling Nb content. The steel casting smelting method comprises the steps of smelting crude steel with an EAF, refining with an LF, smelting with a VOD furnace and adjusting ingredient in the LF, specifically, the contents of elements such as C, Cr, Ni and Mo are adjusted in the step of refining with the LF, the content of C is reduced in the step of smelting with the VOD furnace, and the contents of elements such as Cr, Mn, V and C, Ni, Mo and Nb are adjusted in the step of adjusting ingredient in the LF until technological requirements are met. According to a controlling method, the recovery rate of the Nb content can reach more than 95% and increases by 35% compared with the previous recovery rate being 60%; the accuracy rate of Nb element can reach 98% or more; the content of Nb element in molten steel is controlled accurately by the controlling method, so that the problem that the Nb element cannot be controlled due to the Nb element is oxidized and reduced is solved; and although the Nb content is low in the molten steel, it can be guaranteed that the Nb content does not exceed the standard through the controlling method.

Description

technical field

[0001] The invention relates to the technical field of steel casting smelting, in particular to a steel casting smelting method for controlling Nb content. Background technique

[0002] Nb is added to the steel as a microalloying element, which can change the microstructure of the steel, and has a good fine-grain strengthening and dispersion strengthening effect on the steel; Nb can form stable carbides and carbon nitrogen with C and N in the steel Carbides, but also can disperse carbides, and form steel with fine grain. Nb can also realize the dispersed distribution of precipitates by inducing precipitation and controlling the cooling rate, and adjust the toughness level of steel in a wide range. Therefore, adding Nb can not only increase the strength of steel, but also improve the toughness, high temperature oxidation resistance and corrosion resistance of steel, reduce the brittle transition temperature of steel, and obtain good welding performance and fo...