Production method of high strength steel with composite microstructure

摘要

It is described a production method of high strength grain non-oriented electrical steel with composite microstructure across the metal sheet depth. The steel contains the basic elements in the following weight percentages: 0.5 to 4 % of Si, from 0.05 % C, 0.1 to 1.5 % of Mn, 0,05 to 2 % of Al, 0.001 to 0.2 % of V. The steel is vacuum treated, continually casted, heat rolled, cold rolled with one or two rolling processes with intermediate annealing, and continuously annealed. Consequently, the steel is carburized into the selected sheet depth in gaseous or solid carburization environment at the temperature from 650 °C to 850 °C during 2 to 60 minutes. Consequently, the steel is cold rolled with reduction from 1.5 to 8 %, then it is continuously annealed at the temperature from 850 °C to 1000 °C. The annealing time is from 1 minute to 6 minutes in decarburization atmosphere.