A method for preparing boron-containing microalloy steel by using boron-containing pig iron as a boron-adding agent

Abstract

The invention provides a method for preparing boron-containing micro-alloy steel by using boron-containing pig iron as a boron charging agent, and belongs to the technical field of metallurgy. The method comprises the following steps: (1) preparing industrial pure iron, the boron-containing pig iron, ferro-titanium, manganese metal, iron-carbon alloy, ferro-silicon alloy and pure aluminium serving as raw materials according to predetermined components; (2) adding the prepared industrial pure iron and iron-carbon alloy to an induction furnace, melting the materials, sequentially adding the ferro-silicon alloy, the pure aluminium, the ferro-titanium, the manganese metal and the boron-containing pig iron, melting under a vacuum condition, and feeding argon for refinement; (3) after ending refinement, casting into cast ingots, then heating to 1200+ / -10 DEG C, and preserving heat for 0.5-2 hours; (4) rolling the cast ingots subjected to heat preservation by two stages; and carrying out final rolling, thus obtaining roll steel; and (5) continuously cooling the roll steel to 530-560 DEG C at the rate of 40-50 DEG C / s, and then carrying out air cooling to room temperature, thus obtaining the boron-containing micro-alloy steel. The method has the advantages that the composite cost is low, the industrialization is easy to realize, and the prepared product has excellent performances and good application prospect.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a method for preparing boron-containing microalloy steel by using boron-containing pig iron as a boron-adding agent. Background technique [0002] The boron-containing pig iron obtained by using the blast furnace iron-boron separation process has the characteristics of convenient source, cheap price, and stable performance. It is mainly used as a boron additive for the production of wear-resistant cast iron. In order to make more reasonable use of limited boron resources, boron-rich slag is mainly extracted from boron iron ore, while the remaining boron-containing pig iron can be used in other aspects. [0003] Using boron-containing pig iron to directly smelt boron steel is a research topic with practical significance and rational utilization of boron ore resources. The boron steel smelted directly with boron-containing pig iron as raw material does not have high...

AI Technical Summary

Problems solved by technology

The boron steel smelted directly with boron-containing pig iron as raw material does not have high requirements on the grade of boron in boron-containing pig iron. Due to the high content of silicon and sulfur in boron-containing pig iron, it is necessary to fully desilicate and desulfurize boron-containing pig iron; The boron content in boron pig iron is about 0.20~1.0%. In order to ensure that the boron content in the smelted boron-containing steel is within the range specified by the national standard (≤0.0040%), most of the boron is directly oxidized or nitrided during the smelting process, resulting in The actual recovery rate of boron is low; in order to make full use of the boron element in boron-containing pig iron, it is necessary to find another way for the reuse of boron-containing pig iron