Abstract: During the production of thin and high-grade NGO products on a certain silicon steel annealing coating line, there is a phenomenon of blackening on the surface of the strip. After analyzing the annealing furnace production conditions,and product appearance, this article takes measures to improve the airtightness of the annealing furnace and optimize the process system. Combined with actual production adjustments and optimizations, it reduces the oxidation on the surface of high-grade non oriented silicon steel strip, thereby reducing the blackening phenomenon on the surface of the strip.

Key words: blackening, oxidation, electrical steel, annealing, surface of strip