Method for producing grain oriented electrical steel strip and grain oriented electrical steel strip

Abstract

A method is used to produce a grain-oriented electrical steel strip having optimized magnetic properties. The method may utilize a steel comprising in percent by weight 2.0-4.0% Si, 0.010-0.100% C, at most 0.065% Al, at most 0.02% N, and optionally further constituents, the balance being iron and unavoidable impurities. The steel may be processed to give a cold strip, which may then be subjected to oxidation / primary recrystallization annealing. The resultant cold strip may have an oxide layer to which an annealing separator layer is applied. In a subsequent high-temperature anneal, a forsterite layer forms therefrom, and an insulation layer may be applied thereto prior to a final anneal. After the oxidation / primary recrystallization anneal, a spectrum of the oxide layer obtained is determined by way of FTIR, and an area (Fe2SiO4) is determined for a peak representing Fe2SiO4 molecules present in the oxide layer and is at 980 cm−1, and an area (αSiO2) for a peak representing αSiO2 molecules present in the oxide layer and is at 1250 cm−1. Then the composition of the steel, parameters for the cold rolling, parameters for the oxidation / primary recrystallization anneal, or parameters for a hot strip anneal are adjusted such that 0.5×area (Fe2SiO4)≤area (αSiO2)≤2×area (Fe2SiO4).

Description

technical field [0001] The invention relates to a method for producing a grain-oriented electrical steel strip and to a grain-oriented electrical steel strip. Background technique [0002] Where in this application reference is made to "electrical steel strip" it is meant electrical steel sheet and strip produced by rolling steel of suitable composition and the slabs or trims divided therefrom, which specify For the production of components for electrical engineering applications. [0003] Here, grain-oriented electrical steel strips of the type mentioned here are particularly suitable for applications in which particularly low hysteresis losses are important and high requirements are placed on the magnetic permeability or polarization. These requirements are especially present in components for power transformers, distribution transformers and higher value small transformers. [0004] As specified, for example, in EP 1025268 B1, in the process of producing electrical stee...

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Problems solved by technology

In combination with the microscopy method as suggested in the second aforementioned article by Jung et al also no conclusions can be given which can account for the oxide layer in such a way that direct conclusions for practical applications can be drawn

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