SILICON STEEL, ITS PRODUCTION, PRODUCTION OF ROLLED SILICON STEEL SHEET AND ELECTRIC APPARATUS PROVIDED WITH THE SILICON STEEL

摘要

PROBLEM TO BE SOLVED: To increase the electrical resistivity of steel and to reduce eddy current loss therein by allowing it to contain oxides of La. ;SOLUTION: The preferable range of the content of La in the steel is 0.05 to 2.0 wt.%. On the other hand, the preferable range of the content of Si is 3 to 10 wt.%. As to the production of the steel, La and an Fe-Si compd. are melted by a high-frequency melting method or the like to make an ingot of an Fe-Si-La compd., which is subjected to coarse crushing and pulverizing to form into the powder of an Fe-Si-La compd. Next, this powder is sintered by using an ordinary powder metallurgical method to form La-contg. sintered silicon steel. This silicon steel has a structure in which La oxides 32 are precipitated into the grain boundaries of Fe-Si compd. crystal grains 30. For increasing its workability in cold rolling, the average crystal grain size of the silicon steel before the cold rolling is preferably controlled to η300 μm. Moreover, the sintering can be executed under the conditions of temp.: 1000 to 1150°C, time: 1 to 5 hr and atmosphere: inert gas or the like.;COPYRIGHT: (C)2000,JPO