Continuous casting method of steel

Patent metadata

Field	Value
Publication number	US-10406597-B2
Application number	US-201615546401-A
Country	US
Kind code	B2
Filing date	Jan 22, 2016
Priority date	Jan 30, 2015
Publication date	Sep 10, 2019
Grant date	Sep 10, 2019

Abstract

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.

First claim

The invention claimed is:

1. A continuous casting method of steel, the method comprising:
step (a)—filling molten steel into a continuous casting mold that cooled;
step (b)—solidifying the molten steel with the filling to form a cast slab; and
step (c)—drawing the cast slab from the mold while spraying cooling water toward the cast slab,
wherein:
a cooling water spray amount W 0 [kg/ton-cast slab] where solidification of molten steel in the cast slab is completed is set as a predetermined target position under a condition where a drawing speed V of the cast slab is set to a speed V 0 [m/min],
a cooling water spray amount W 1 [kg/ton-cast slab] is set as the target position under a condition where the drawing speed V of the cast slab is set to a speed V 1 [m/min], which differs from the speed V 0 , and
the step (c) further comprises:
drawing the cast slab from the mold at the speed V 0 while spraying cooling water to the cast slab such that cooling water spray amount is set to W 0 , and
then changing the drawing speed V of the cast slab to V 1 while spraying cooling water to the cast slab such that the cooling water spray amount is set to W 1 ,
wherein:
a cooling water spray amount Wt [kg/ton-cast slab] is an amount of cooling water that is sprayed to the cast slab during a period of time t [min],
 the period of time t being obtained by dividing a target length Lt of the cast slab from an exit of the mold to the target position along the casting direction by the drawing speed V 0 , and
 the period of time t beginning from a point of time Tc at which the drawing speed V is changed, and
a cooling water spray amount Wt [kg/ton-cast slab] during the period of time t satisfying either formula (1) or formula (2):
Wt<W1 under a condition of V1<V0  (1)

Wt>W1 under a condition of V1>V0  (2).

2. The continuous casting method of steel according to claim 1 , wherein the cooling water spray amount Wt during the period of time t changes in n subsequent stages (n: natural number of 1 or more) from a stage where the water cooling spray amount is Wt, to a spray amount Wt (i− 1 ) (i: natural number from 1 to n) in an (i− 1 )th stage, to a spray amount Wt (i) in an ith stage such that either formula (3) or formula (4) is satisfied:
Wt≤Wt ( i− 1) <Wt ( i ) <W 1under a condition of V 1 <V 0  (3)

Wt≤Wt ( i− 1) >Wt ( i ) >W 1under a condition of V 1 >V 0  (4)

wherein W( 0 ) is Wt in the formula (3) and the formula (4).

3. The continuous casting method of steel according to claim 1 , wherein:
when formula (1) is satisfied during the period of time t, the cooling water spray amount Wt is equal to a value that is 1.2 times or less an optimum value, and
when formula (2) is satisfied during the period of time t, the cooling water spray amount Wt is equal to a value that is 0.8 times or more than the optimum value.

Assignees

• Jfe Steel Corp

Inventors

• Toishi Keigo
• Ohno Hiroyuki
• Aramaki Norichika
• Miki Yuji

Classifications

• B22D11/124

  for cooling · CPC title

• B22D11/225

  for secondary cooling · CPC title

• B22D11/207

  responsive to thickness of solidified shell · CPC title

• B22D11/1282

  Vertical casting and curving the cast stock to the horizontal · CPC title

• B22D11/1206 Primary

  for plastic shaping of strands (rolling mills B21B1/46) · CPC title