Method for preventing internal oxidation layer in normalization treatment of electrical hot-rolled strip steel

Abstract

The invention relates to a treatment method of hot-rolled steel plates, in particular a method for preventing an internal oxidation layer from generating in the non-oriented normalization treatment of electrical hot-rolled strip steel. The normalization treatment comprises a preheating section, a non-oxidation heating section, an even heating section and a cooling section, wherein the non-oxidation heating section adopts direct fire heating and has an air-fuel ratio coefficient of 0.85-0.95. An even heating furnace adopts electric heating or radiation tub heating in the atmosphere of N2 under the condition that in-furnace dew point is 65-10 DEG C below zero and oxygen content is not more than 0.1 percent. The invention reduces and eliminates the internal oxidation layer generated during the normalization of a hot-rolled strip steel during controlling the normalization process, radically eliminates furnace roller nodulation generated in final anneal, avoids subsequent furnace roller nodulation cleaning work, improves the efficiency and decreases the cost.

Description

technical field The invention relates to a treatment method of hot-rolled steel plates, in particular to a method for preventing the generation of internal oxide layers in the normalization treatment of hot-rolled strips of non-oriented electrical steel. Background technique Cold-rolled non-oriented electrical steel with high magnetic induction and low iron loss is a hot spot in the development of non-oriented electrical steel in recent years. It is developed to meet the requirements of high efficiency and miniaturization of various types of motors and electronic transformer cores. The usual production methods of this electrical steel include slab hot rolling, normalizing treatment, cold rolling and annealing treatment. Normalization is a commonly used process for cold-rolled non-oriented electrical steel with high magnetic induction and low iron loss. The purpose is to obtain a coarse grain structure of the hot-rolled sheet before cold-rolling, and to obtain a high-strength...

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Problems solved by technology

Japanese patent publication 2-149622 adopts the method of normalization after pickling, and reduces the inner oxide layer by eliminating the oxygen diffusion of the reduction of the outer oxide layer. This method increases the production process and is used in the continuous normalization pickling unit. difficult to implement

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