| 摘要 |
PROBLEM TO BE SOLVED: To produce a hot rolled steel plate excellent in flash weldability and upset weldability, and a nonriented silicon steel sheet produced by using the hot rolled steel plate as a stock. SOLUTION: This hot rolled steel plate has a composition consisting of, by weight, >=1.0% Si, >=0.004% Al, 0.1-0.8% Mn, <=0.2% P, <=0.02% S, <=0.005% C, <=0.005% N, and the balance essentially Fe. At this time, the number of inclusions in the steel plate is as follows: the number of inclusions of 0.1-1.0μm diameter is >=5000pieces/mm<2> and that of >1.0μm diameter is <=400pieces/mm<2> ; or the number of inclusions of 0.1-1.0μm diameter is <=3000pieces/mm<2> and that of >1.0μm diameter is >=400pieces/mm<2> ; or the number of inclusions o 0.1-1.0μm diameter is >=3000pieces/mm<2> and that of >1.0μm diameter is >=200 pieces/mm<2> . The nonoriented silicon steel sheet is produced by using this steel plate as a stock.
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