Abstract: A full cone spray nozzle comprising: a nozzle body (1) having a liquid inlet (3) at its upstream end and a spray orifice (4) at its downstream end; a vane structure (2) of an axial direction length (W) and diameter (D) arranged with its outer circumferential surface in contact with the inside of the nozzle body (1); has a plurality of channel grooves (6) of width (T) and depth (H) at the outer circumferential surface of the vane structure (2); an upstream side projecting part (8) of a length (U) in the axial direction of the nozzle body (1) at an upstream side of the vane structure (2); a downstream side projecting part (9) of a length (P) in the axial direction of the nozzle body (1) at a downstream side of the vane structure (2); and a swirl flow chamber (5) of an axial direction length (L) which is a space formed by an inside wall surface of the nozzle body (1), the vane structure (2) and the spray orifice (4), wherein 0.25?T/D?0.30, 0.25?H/D?0.30, and 1.5?L/W?3.5 are satisfied.

Abstract: A full cone spray nozzle comprising: a nozzle body (1) having a liquid inlet (3) at its upstream end and a spray orifice (4) at its downstream end; a vane structure (2) of an axial direction length (W) and diameter (D) arranged with its outer circumferential surface in contact with the inside of the nozzle body (1); has a plurality of channel grooves (6) of width (T) and depth (H) at the outer circumferential surface of the vane structure (2); an upstream side projecting part (8) of a length (U) in the axial direction of the nozzle body (1) at an upstream side of the vane structure (2); a downstream side projecting part (9) of a length (P) in the axial direction of the nozzle body (1) at a downstream side of the vane structure (2); and a swirl flow chamber (5) of an axial direction length (L) which is a space formed by an inside wall surface of the nozzle body (1), the vane structure (2) and the spray orifice (4), wherein 0.25?T/D?0.30, 0.25?H/D?0.30, and 1.5?L/W?3.5 are satisfied.

Abstract: The present invention provides a method of cooling a hot-rolled steel strip which has passed through a finishing rolling, including: cooling the hot-rolled steel strip from a first temperature of not lower than 600° C. and not higher than 650° C. to a second temperature of not higher than 450° C. with cooling water having the water amount density of not lower than 4 m3/m2/min and not higher than 10 m3/m2/min, wherein with respect to the area of the target surface, the area of a portion where a plurality of spray jets of the cooling water directly strikes on the target surface is at least 80%.

Abstract: The present invention provides a method of cooling a hot-rolled steel strip which has passed through a finishing rolling, including: cooling the hot-rolled steel strip from a first temperature of not lower than 600° C. and not higher than 650° C. to a second temperature of not higher than 450° C. with cooling water having the water amount density of not lower than 4 m3/m2/min and not higher than 10 m3/m2/min, wherein with respect to the area of the target surface, the area of a portion where a plurality of spray jets of the cooling water directly strikes on the target surface is at least 80%.

Abstract: The present invention provides a method for cooling a hot-rolled steel strip after a finishing rolling in which a transportation speed varies, the method including: setting a transportation-speed changing schedule on the basis of a temperature of a steel strip before the finishing rolling and a condition of the finishing rolling; performing a first cooling in which the hot-rolled steel strip is cooled under a film boiling state in a first cooling section; performing a second cooling in which the hot-rolled steel strip is cooled with a water amount density of not less than 2m3/min/m2 in a second cooling section; and coiling the hot-rolled steel strip, in which a cooling condition is controlled in the first cooling so as to satisfy 0.8?(T2a??T2a)/?Tx?1.2.

Abstract: The present invention provides a method of cooling a hot-rolled steel strip which has passed through a finishing rolling, including: cooling the hot-rolled steel strip from a first temperature of not lower than 600° C. and not higher than 650° C. to a second temperature of not higher than 450° C. with cooling water having the water amount density of not lower than 4 m3/m2/min and not higher than 10 m3/m2/min, wherein with respect to the area of the target surface, the area of a portion where a plurality of spray jets of the cooling water directly strikes on the target surface is at least 80%.

Abstract: The present invention provides a method for cooling a hot-rolled steel strip after a finishing rolling in which a transportation speed varies, the method including: setting a transportation-speed changing schedule on the basis of a temperature of a steel strip before the finishing rolling and a condition of the finishing rolling; performing a first cooling in which the hot-rolled steel strip is cooled under a film boiling state in a first cooling section; performing a second cooling in which the hot-rolled steel strip is cooled with a water amount density of not less than 2 m3/min/m2 in a second cooling section; and coiling the hot-rolled steel strip, in which a cooling condition is controlled in the first cooling so as to satisfy 0.8?(T2a??T2a)/?Tx?1.2.

Abstract: The present invention provides a method of cooling a hot-rolled steel strip which has passed through a finishing rolling, including: cooling the hot-rolled steel strip from a first temperature of not lower than 600° C. and not higher than 650° C. to a second temperature of not higher than 450° C. with cooling water having the water amount density of not lower than 4 m3/m2/min and not higher than 10 m3/m2/min, wherein with respect to the area of the target surface, the area of a portion where a plurality of spray jets of the cooling water directly strikes on the target surface is at least 80%.