| 摘要 |
PURPOSE:To prevent the generation of internal cracking by dividing the secondary cooling zone of steel of which the contents of P and Si are set at prescribed amts. or below to multiple zones and setting the difference in the area ratio water flow between the adjacent zones and cooling ratio water flow at prescribed values or below. CONSTITUTION:The contents of P and Si in Nb-contg. stainless steel are set at (P+0.04 Si) <=0.03%. The secondary cooling zone of a continuous casting device is divided to n-pieces of zones, and the difference in area ratio water flow QK-Qk+1 expressed by the K-th zone from the mold side is set at <=6X10<-3>l/ mm..cm<2>. The secondary cooling ratio water flow W expressed by the equation II is set at <=0.6l/kg, whereby the steel is slowly cooled. In this way, the internal cracking of the steel is prevented. |
