A rh refining method for aluminum-free and non-oriented silicon steel

Abstract

The invention relates to the field of ferrous metallurgy and in particular relates to an RH refining method for aluminium-free non-oriented silicon steel. The RH refining method for the aluminium-free non-oriented silicon steel is characterized in that an alloy adding sequence in an RH refining process of cold-rolled aluminium-free non-oriented silicon steel is changed, firstly P iron is added, then deoxygenated silicon iron and ingredient silicon iron are added, and finally Mn iron is added, so that harmful residual elements such as Nb, V and Ti in alloy form large-particle oxide under the condition of high oxygen value of molten steel, and the large-particle oxide floats into steel slag upward. Compared with the prior art, the RH refining method for the aluminium-free non-oriented silicon steel has the beneficial effects that the alloy adding sequence in a refining process is changed, contents of harmful elements such as Nb, V and Ti in P iron, and Si iron in the molten steel are effectively reduced, the contents of Nb, V and Ti are respectively reduced to below 10PPm, electromagnetic property of silicon steel is improved, average iron loss P1.5 is reduced by 0.30W / Kg and average magnetic induction value B5000 is increased by 0.010T.

Description

technical field [0001] The invention relates to the field of iron and steel metallurgy, in particular to an RH refining method for aluminum-free and non-oriented silicon steel. Background technique [0002] The most critical technical index of silicon steel is electromagnetic properties, that is, low iron loss and high magnetic induction are required. The content of harmful residual elements in steel plays a key role in the influence of electromagnetic properties of electrical steel. The control of residual elements is mainly reflected in the refining process. During the refining process of steel, the alloys of aluminum-free and non-oriented silicon steel are all added during the refining process. The traditional order of adding alloys is: adding deoxidized Al line → adding Mn iron → adding ferrosilicon → adding P iron, and the molten steel reaches the time of refining RH , There are a lot of oxygen and carbon elements in molten steel. During the RH refining process of silic...

AI Technical Summary

Problems solved by technology

However, both ferrophosphorus and ferrosilicon contain a certain amount of Nb, V, Ti and other elements. In the absence of oxygen molecules in the steel, they cannot form oxides and float up. These elements form nitrogen carbides. These nitrogen carbide particles are small. Usually 10-100nm, and the quantity is large, which hinders the growth of recrystallized grains during the continuous annealing process of cold-rolled sheets and affects the electromagnetic properties of silicon steel. The more this nitrogen carbide content, the worse the electromagnetic properties of silicon steel. At present, The chemical composition test of the finished product shows that the contents of Nb, V and Ti are all above 40ppm

Taking 50W800 as an example, the iron loss value reaches P1.5=5.0W / Kg, and the magnetic induction value B5000=1.732T. The iron loss value is higher, the magnetic induction is slightly lower, and the electromagnetic performance is poor.