METHOD FOR PRODUCING HIGH-GRADE NON-ORIENTED ELECTRICAL STEEL SHEET

摘要

PROBLEM TO BE SOLVED: To solve such a problem that it is difficult to obtain excellent magnetic characteristics since many fine-precipitated materials are caused on the hot-rolled sheet, and recrystallization and grain-growth are insufficient with a non-water pouring after hot-finish-rolling because of that the heating temperature of a slab is high at the time of producing a high-grade non-oriented electrical steel sheet by eliminating a hot-rolled sheet annealing.;SOLUTION: The high-grade non-oriented electrical steel sheet contains one or two of REM and Ca of each 0.0005-0.03%. The excellent magnetic characteristics can be obtained by defining the heating temperature of the slub as 1,230-1,320°, a hot-rolling finish temperature as ≥1,050°C and a non-pouring water time after hot-rolling as 1.5-4sec. Further, the more excellent magnetic characteristics can be obtained by performing the slab-heating in the temperature range of ≥1,230°C with an atmosphere control-type electric-heating furnace, thereby suppressing rough-rolling biting defects and the developing ratio of surface flaws, and also performing the rolling of 5-40% rolling-reduction ratio before heating the at ≥1,230°C.;COPYRIGHT: (C)2009,JPO&INPIT