Method for increasing equiaxed grain rate of low-carbon high-silicon steel billet

Abstract

The invention provides a method for increasing the equiaxed grain rate of a low-carbon high-silicon steel billet. The method comprises the step that when low-carbon high-silicon steel is cast, the components of molten steel are supposed to meet the requirements of 0.001<C (mass%)<0.004, 1.10<Si (mass%)<1.75, 0.010<P (mass%)<0.030, 0.15<Al (mass%)<0.35, (Ce mass%-5.8*O mass%)*(S mass %)>1.5*10<-7>, and (Ce mass %-5.8*O mass %)>1 / 34*(Mn mass %). By the adoption of the method, corrugated defects can be prevented from occurring in the rolling direction in the subsequent rolling process, the equiaxed grain rate is increased to be 20% or above, precipitation of micro MnS is restrained, and the magnetism of the low-carbon high-silicon steel is improved.

Description

Technical field: [0001] The invention relates to a method for increasing the equiaxed crystal ratio of a low-carbon high-silicon steel slab, and belongs to the technical field of steel production. Background technique: [0002] Generally, after the solidification of molten steel, a billet low-magnification structure consisting of fine equiaxed crystals, columnar crystals and central coarse equiaxed crystals is formed. At present, it is generally believed that the development of columnar crystals in steel slabs will cause the structure to have banded characteristics, and the mechanical properties will be anisotropic, especially the transverse properties and toughness will be reduced. When the columnar crystal is fully developed, the billet is easy to form a transgranular structure, resulting in central porosity, shrinkage cavity and central segregation. [0003] For low-carbon high-silicon steel, due to its compositional characteristics, it is easy to form a transgranular ...

AI Technical Summary

Problems solved by technology

However, in the process of casting non-oriented silicon steel, MnS below 1 μm will be generated. This fine and dispersed MnS will act as a pinning effect in the subsequent heat treatment process to prevent grain growth, thereby deteriorating the magnetic properties (iron loss) of non-oriented silicon steel.

[0008]For the low-carbon high-silicon steel whose primary phase is high-temperature ferrite (δ-Fe), it is not easy to make the billet form equiaxed grain rate by traditional method The solidified structure cannot effectively prevent defects from forming inside the billet

It also cannot effectively solve the problem of low loss of low-carbon high-silicon steel due to the fine grain size due to the precipitation of fine MnS.