PRODUCTION OF DIRECTIONAL SILICON STEEL PLATE OF SUPERIOR REPETITIVE BENDING CHARACTERISTIC

摘要

PURPOSE:To improve repetitive bending characteristics by subjecting a cold-rolled directional silicon steel plate to decarburization annealing then forming subscale on the surface and further coating an annealing separating agent and performing final finish annealing based on specific conditions. CONSTITUTION:A cold-rolled steel plate of silicon steel is subjected to intermediate annealing for 5min at 900 deg.C, after which it is cold-rolled to final thickness. This cold-rolled silicon steel plate is subjected to decarburization annealing in wet hydrogen for 3min at 820 deg.C, after which subscale contg. SiO2 is formed on the surface, further an annealing separating agent comprising essentially MgO is coated thereon, and the plate is subjected to final annealing. The annealing separating agent contg. Ti compound of 0.5-5wt% in Ti equiv. and comprising essentially MgO is used. The final finish annealing is accomplished by heating and temp. raising at rates of average 5-15 deg.C/hr for a 950-1,050 deg.C temp. range and holding the temp. of =1,170 deg.C for =4hrs. The heating in a region of =950 deg.C is executed in a hydrogen atmosphere.