| 摘要 |
PURPOSE:To produce a soft magnetic material coasening crystalline grain size and having excellent magnetizing characteristic by slowly cooling mild steel material having only a little impurity content after working under the specific temp. condition. CONSTITUTION:The mild steel raw material composing of 0.02-0.08wt.% C, <0.10% Si, 0.05-0.50% Mn, <0.020% Al, <0.040% N and the balance Fe, is heated in the austenitic range of >=100 deg.C and hot working of hot forging, hot rolling, hot pressing, etc., is executed to produce rotor material, etc., for generator, etc. In this case, the finishing temp. of the above hot working is made to >=1000 deg.C and after that, by slowly cooling at <=0.5 deg.C/sec cooling velocity, the grain size of the austenitic crystal is coasened at >=50mum and the soft magnetic material having excellent magnetizing characteristic, such as >=4500 the max. permeability is produced. |
