Heat treatment process for medium and small cold rolled silicon steel sheet

Abstract

The heat treatment process for medium and small cold rolled silicon steel sheet completed in common bell type electric furnace includes the following steps: loading, vacuumizing and filling with nitrogen, heating while introducing nitrogen-hydrogen mixed gas and water vapor to form water vapor diaphragm between silicon steel sheets to avoid adhesion; decarbonizing to form ferrite completely for silicon steel sheet to reach low carbon content, low hysteresis loss and low magnetic resistance; and slowly cooling after decarbonizing for silicon steel sheet to separate out [100] crystal direction ferrite crystal completely under austenitic state so as to increase magnetic conductivity and magnetic flux and lower iron loss P15/50. The said process can reach excellent heat treatment effect, and the treated cold rolled silicon steel sheet can meet the requirement for use in motor.

Description

technical field [0001] The invention relates to cold-rolled silicon steel sheets, in particular to heat treatment of cold-rolled silicon steel sheets, in particular to a heat treatment method for small and medium-sized cold-rolled silicon steel sheets, and belongs to the technical field of small and medium-sized metallurgical processing. Background technique [0002] In recent years, with the rapid development of the household appliance industry, the demand for small and medium-sized motors has increased greatly; at the same time, in the automation system, a large number of small and medium-sized motors and micro-motors are also required. In this context, the market demand for silicon steel sheets has risen sharply. Due to the poor electromagnetic properties of ordinary hot-rolled silicon steel sheets, the motors made of them have low efficiency. However, the supply of cold-rolled silicon steel sheets produced by large steel mills is relatively tight and the price is high. A...

AI Technical Summary

Problems solved by technology

Due to the poor electromagnetic properties of ordinary hot-rolled silicon steel sheets, the efficiency of the motors made is low. However, the supply of cold-rolled silicon steel sheets produced by large steel mills is relatively tight and the price is high. At present, it largely depends on imports.

If the production method of a large steel factory is used to produce silicon steel sheets to meet the market, not only the investment is large - especially the decarburization and recrystallization annealing process, a continuous annealing furnace with a length of more than 300 meters is required, and continuous production is required, and the annual production scale cannot be low less than one million tons, otherwise the production cost will be unbearable

On the other hand, if a general pit furnace is used to process silicon steel sheets, when the temperature is raised to the temperature required by the process, the steel sheets will be seriously bonded, the surface will be rough, and the electromagnetic properties will be low, which cannot meet the processing requirements of subsequent products.