| 摘要 |
PROBLEM TO BE SOLVED: To produce a small cross-sectional round billet of martensitic and ferritic stainless steel by a continuous casting machine in such manner that the surface cracking of the billet caused by transformation stress and thermal stress at the time of cooling the billet are efficiently prevented. SOLUTION: Mertensitic stainless steel or ferritic stainless steel is cast into a round billet whose cross-sectional size is <=350 mm by diameter by a continuous casting machine, after the casting, the round billet is cooled till the surface temp. of the billet reaches <=100 deg.C in the air, next, the round billet is heated to a range from the temp. lower than the Ac1 point by 200 deg.C to the temp. higher than the Ac1 point by 100 deg.C at a temp. rising rate of 10 to 200 deg.C/Hr, and, after the heating, cooling is executed till the surface temp. of the billet reaches <=100 deg.C in the air or in a surface.
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