| 摘要 |
PROBLEM TO BE SOLVED: To execute rolling for silicon steel having a specified Si content by kneading silicon steel metal powder with agar in which sol-gel transformation occurs and water as a binder, executing sintering after molding to produce a sintered body having the not more than the specified average crystal grain size and specified thickness and executing rolling. SOLUTION: A kneaded material is sintered to produce a sintered body with <=300 average crystal grain size and <=5 mm thickness, which is rolled to a required thickness to obtain silicon steel in which the content of Si is controlled to >=3, preferably, to 10 wt.%. The amt. of agar to be added is preferably controlled to 0.6 to 4.0 wt.%. The amt. of water to be used mixedly with the agar is preferably controlled to 7 to 15 wt.%, and when forming the binder, the temp. is desirably controlled to 92 to 96 deg.C at which the agar is sufficiently melted, but, desirably, the kneading temp. with the metal powder is controlled to 60 to 65 deg.C, and the extrusion molding temp. is controlled to 50 to 55 deg.C. The sintering temp. differs in accordance with the compsn., average grain size, raw material powder, but is generally controlled to 1150 to 1300 deg.C, and it is executed preferably in a gaseous hydrogen atmosphere or in a vacuum.
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