PROCESS FOR PRODUCING COLD-ROLLED STEEL STRIP HAVING A Si-CONTENT OF AT LEAST 3.2 WT.- USED FOR ELECTROMAGNETIC PURPOSES

摘要

The invention relates to a cold-rolled steel strip or sheet metal having a thickness of = 0.7 mm and used for electromagnetic purposes. Said strip consists of a steel containing (in wt. %) C: 0.01 %, Si: 3.2 - 7 %, Al: 2 %, Mn: ≤ 1 %, the remainder being iron and other impurities. After being melted to form a starting product, such as a slab, a thin slab or a thin strip, said product is cast and is then heated to a temperature TR 1000 °C, and hot-rolled to form a heated strip at a hot-rolling temperature TF 800 °C. Said heated strip is then cooled from a temperature TC of at least 750 °C but less than 850 °C to a temperature of less than 300 °C, at a cooling speed ΔT/Δt of at least 400 °C/min. After cooling, the steel strip is subjected to a surface treatment such as mechanical de-scaling and/or etching. After the surface treatment, the steel strip is cold-rolled at a maximum temperature TCR of 500 °C and is then annealed.