Pre-melted slag for refining ultra-low aluminum steel and preparation method and using method thereof

Abstract

The invention relates to pre-melted slag for refining ultra-low aluminum steel and a preparation method and a using method thereof. The preparation method comprises the steps of firstly burdening BaO, CaO, MgO, B2O3, CaC2 and SiO2 according to a proportion, pre-melting at the temperature of 1450-1500 DEG C, cooling, then breaking into blocky materials, and packaging in a moisture-proof mode. The pre-melted slag is used for secondary refining and slagging by a ladle furnace, after pre-deoxidization of molten steel, slag pulling of a ladle and reduction treatment of residual slag, the ladle is added when the ladle is allocated and transported to a refining bay, and the pre-melted slag can be put into the ladle in the LF (ladle furnace) refining or the ladle argon blowing process. Compared with alkaline refined slag adopted in the prior art, the pre-melted slag has the advantages of absorbing Al2O3 in the steel to the greatest extent and promoting the reaction of O and Al in the steel so as to control the Al content below 0.004%; in addition, the pre-melted slag provided by the invention has the advantages of wide raw material sources, simple method and significant economic benefits and social benefits, and is favorable for reducing the cost and protecting the environment.

Description

technical field [0001] The invention belongs to the field of ladle metallurgy for refining outside a steelmaking furnace, and particularly relates to a pre-melted slag for refining ultra-low aluminum steel, a preparation method and a using method, which are suitable for slagging and refining in a ladle for secondary refining of steelmaking. Background technique [0002] With the development of social economy, users have put forward higher and higher requirements for the quality of steel products. As an important production process in the modern steelmaking process, extra-furnace refining plays a pivotal role in the entire steel production process; in many In the refining process, synthetic slag refining has the functions of removing harmful elements in steel and absorbing inclusions in steel, and has been widely used and developed. [0003] At present, the refining slag outside the steelmaking furnace mainly includes the following basic series: CaO-CaF 2 Slag system, CaO-Al...

AI Technical Summary

Problems solved by technology

[0004] The ladle refining slag in the prior art is mainly designed for desulfurization and dephosphorization functions. For the ladle refining of ultra-low aluminum steel, there are two main deficiencies: (1) The alumina content in the ladle refining slag is high, which leads to the ladle refining process. The ability to absorb alumina in steel is reduced, and the alumina in the slag is reduced in a strong reducing atmosphere to add aluminum to the steel, which is not suitable for smelting aluminum-free or ultra-low aluminum steel grades; (2) ladle refining slag is basically Alkaline slag or high alkalinity slag is used above to make it have strong desulfurization and dephosphorization capabilities, but from CaO-SiO 2 -Al 2 o 3 From the phase diagram, Al 2 o 3 The range of components that can generate low-melting point compounds in high-basic slag is very small, so the solubility of alumina in alkaline or high-basic slag is very low, which can easily lead to insoluble Al in slag 2 o 3 It enters molten steel under reducing atmosphere, so it is not suitable for smelting ultra-low aluminum steel