Abstract: In a mold for continuously casting a round billet with a curved type continuous casting apparatus, assuming that D0 (m) is an inner diameter at a lower mold edge and R0 (m) is a curvature radius of an outer curvature side at the lower mold edge, when a rate of change Tp (%/m) in mold inner diameter per unit length along a casting direction is expressed by Formula 1, and when a rate of change Rp (%/m) in curvature radius of an outer curvature side per unit length along the casting direction is expressed by Formula 2, the rate of change Tp in mold inner diameter and the rate of change Rp in curvature radius satisfy a relationship expressed by Formula 3; Tp=(1/D0)×(dD/dx)×100(%/m)??Formula 1 Rp=(1/R0)×(dR/dx)×100(%/m)??Formula 2 where D in Formula 1 is a mold inner diameter at a distance x away from an upper mold edge and R in Formula 2 is a curvature radius of the outer curvature side at the distance x, Rp=(Tp/2)×(D0/R0)??Formula 3 Uniform and good contact is obtained between the billet and a mold inner pe

Abstract: In a mold for casting a billet with a curved type continuous casting apparatus, D0 (m) is an inner diameter at a lower mold edge and R0 (m) is a curvature radius of an outer curvature side at the lower mold edge. When a rate of change Tp (%/m) in mold inner diameter per unit length along a casting direction is Tp=(1/D0)×(dD/dx)×100 (%/m), and when a rate of change Rp (%/m) in curvature radius of an outer curvature side per unit length along the casting direction is Rp=(1/R0)×(dR/dx)×100 (%/m), the rate of change Tp in mold inner diameter and the rate of change Rp in curvature radius satisfy a relationship expressed Rp=(Tp/2)×(D0/R0), where D is a mold inner diameter at a distance x away from an upper mold edge and R in Formula 2 is a curvature radius of the outer curvature side at the distance x.

Abstract: In a mold for casting a billet with a curved type continuous casting apparatus, D0 (m) is an inner diameter at a lower mold edge and R0 (m) is a curvature radius of an outer curvature side at the lower mold edge. When a rate of change Tp (%/m) in mold inner diameter per unit length along a casting direction is Tp=(1/D0)×(dD/dx)×100 (%/m), and when a rate of change Rp (%/m) in curvature radius of an outer curvature side per unit length along the casting direction is Rp=(1/R0)×(dR/dx)×100 (%/m), the rate of change Tp in mold inner diameter and the rate of change Rp in curvature radius satisfy a relationship expressed Rp=(Tp/2)×(D0/R0), where D is a mold inner diameter at a distance x away from an upper mold edge and R in Formula 2 is a curvature radius of the outer curvature side at the distance x.

Abstract: A method for continuously casting a billet with a small cross section in which a curved type or vertical type continuous casting machine is used while oscillating the mold upward and downward is characterized in that the casting machine is provided with a mechanism for withdrawing speed oscillation. The mechanism has structural play in the directions of driving and reverse driving in such a manner that the amount of a play-incurred displacement from the neutral position of the structural play in the direction of billet driving or reverse driving is ±2 to ±30 mm in the direction of driving on the pinch roll circumferential length equivalent basis. The mechanism produces a returning force toward the neutral position and operational parameters such as the billet length, the specific amount of secondary cooling water, the casting speed as well as the oscillation amplitude and frequency are optimized.

Abstract: In a mold for casting a billet with a curved type continuous casting apparatus, D0 (m) is an inner diameter at a lower mold edge and R0 (m) is a curvature radius of an outer curvature side at the lower mold edge. When a rate of change Tp (%/m) in mold inner diameter per unit length along a casting direction is Tp=(1/D0)×(dD/dx)×100 (%/m), and when a rate of change Rp (%/m) in curvature radius of an outer curvature side per unit length along the casting direction is Rp=(1/R0)×(dR/dx)×100 (%/m), the rate of change Tp in mold inner diameter and the rate of change Rp in curvature radius satisfy a relationship expressed Rp=(Tp/2)×(D0/R0), where D is a mold inner diameter at a distance x away from an upper mold edge and R in Formula 2 is a curvature radius of the outer curvature side at the distance x.

Abstract: A method for continuously casting a billet with a small cross section in which a curved type or vertical type continuous casting machine is used while oscillating the mold upward and downward is characterized in that the casting machine is provided with a mechanism for withdrawing speed oscillation. The mechanism has structural play in the directions of driving and reverse driving in such a manner that the amount of a play-incurred displacement from the neutral position of the structural play in the direction of billet driving or reverse driving is ±2 to ±30 mm in the direction of driving on the pinch roll circumferential length equivalent basis. The mechanism produces a returning force toward the neutral position and operational parameters such as the billet length, the specific amount of secondary cooling water, the casting speed as well as the oscillation amplitude and frequency are optimized.