Provided is a continuous casting method of steel that prevents a solidification completion position from being changed even when a drawing speed V of a cast slab is changed. The method includes drawing a cast slab by setting a drawing speed V0 while spraying cooling water to the cast slab at a cooling water spray amount W0 [kg/ton-cast slab]. Then, changing the drawing speed to the speed V1 while spraying cooling water to the cast slab at a cooling water spray amount W1 [kg/ton-cast slab]. The method further includes spraying cooling water to the cast slab at a cooling water spray amount Wt [kg/ton-cast slab] during a period of time t that is obtained by dividing a target length Lt by the drawing speed V0. The water spray amount Wt satisfying either formula (1): Wt<W1 under a condition of V1<V0, or formula (2): Wt>W1 under a condition of V1>V0.

A continuous casting method of steel includes the step of bulging wide side surfaces of a slab having there inside an unsolidified layer with a total intentional bulging amount of 3 to 10 mm by increasing stepwise toward a downstream side in a casting direction a roller gap of a plurality of pairs of slab support rollers disposed in a continuous casting machine.

Conditions for soft reduction are determined in a method of continuous casting in accordance with a method utilizing the thickness of a slab strand to prevent center segregation from occurring in the strand due to an insufficient pressing rate or internal cracks from occurring in the strand due to an excessively high pressing rate.

Using an apparatus for manufacturing a thin steel sheet including the followings which are arranged in order: a continuous casting machine (1) for a thin slab having a slab thickness of 70 mm to 120 mm at a lower end of a mold; a holding furnace (2) that is configured to maintain a temperature of a cast slab (10) and/or heats the cast slab (10); and a rolling stand (3) by which finish rolling is performed, the casting speed of the thin slab is set to 4 to 7 m/min, the slab (10) is reduced at a rolling reduction of 30% or more by the reduction roll (4) after solidification is completed and when a center temperature of the slab is 1300° C. or higher, and the slab (10) is held at a temperature of 1150° C. or higher and 1300° C. or lower for five minutes or longer in the holding furnace (2).

A method to determine the crater end location of a cast metal product during its casting, the crater end location being the location at which the cast metal product becomes fully solidified. A continuous casting method and a continuous casting machine are also provided.

A continuous casting method of steel includes the step of bulging wide side surfaces of a slab having there inside an unsolidified layer with a total intentional bulging amount of 3 to 10 mm by increasing stepwise toward a downstream side in a casting direction a roller gap of a plurality of pairs of slab support rollers disposed in a continuous casting machine.

Conditions for soft reduction are determined in a method of continuous casting in accordance with a method utilizing the thickness of a slab strand to prevent center segregation from occurring in the strand due to an insufficient pressing rate or internal cracks from occurring in the strand due to an excessively high pressing rate.

A method to determine the crater end location of a cast metal product during its casting, the crater end location being the location at which the cast metal product becomes fully solidified. A continuous casting method and a continuous casting machine are also provided.

Provided is a continuous casting method of steel that prevents a solidification completion position from being changed even when a drawing speed V of a cast slab is changed. The method includes drawing a cast slab by setting a drawing speed V0 while spraying cooling water to the cast slab at a cooling water spray amount W0 [kg/ton-cast slab]. Then, changing the drawing speed to the speed V1 while spraying cooling water to the cast slab at a cooling water spray amount W1 [kg/ton-cast slab]. The method further includes spraying cooling water to the cast slab at a cooling water spray amount Wt [kg/ton-cast slab] during a period of time t that is obtained by dividing a target length Lt by the drawing speed V0. The water spray amount Wt satisfying either formula (1): Wt<W1 under a condition of V1<V0, or formula (2): Wt>W1 under a condition of V1>V0.

A continuous caster to cast a metal product has a plurality of upper and lower segment frames bearing rolls, the upper and lower segment frames being located respectively above and below the cast metal product. At least one bending measurer is located on at least one of the upper segment frames and able to emit a bending measurement signal indicative of a bending of the at least one of the upper segment frames. A processor is disposed to receive the bending measurement signal and to calculate a location Pmes of the crater end based on the measured bending signal, the crater end location being the location