Stopper for continuous casting and continuous casting method

Patent metadata

Field	Value
Publication number	US-12023730-B2
Application number	US-201917417461-A
Country	US
Kind code	B2
Filing date	Dec 18, 2019
Priority date	Dec 25, 2018
Publication date	Jul 2, 2024
Grant date	Jul 2, 2024

Abstract

The precision of grasping or controlling backpressure around a gas discharge portion in a stopper for continuous casting can be improved with a stopper for continuous casting which includes a cavity for conveying gas in a vertical direction center of the stopper, one or a plurality of gas discharge holes passing through from the cavity to the outside in a distal center or a side surface of a reduced-diameter region including a fitted portion to a lower nozzle, and a pressure control component in a part of an area above the gas discharge hole within the cavity.

First claim

The invention claimed is:

1. A stopper for continuous casting comprising:
a cavity for conveying gas in a vertical direction center of the stopper;
one or a plurality of gas discharge holes passing through from the cavity to the outside in a distal center or a side surface of a reduced-diameter region including a fitted portion to a lower nozzle; and
a pressure control component in a part of the reduced-diameter region, the part being above the gas discharge hole within the cavity,
wherein the pressure control component is made of a dense refractory having no gas permeability under a condition of pressurizing a sample of the refractory having a length of 20 mm at 8×10 −2 MPa,
wherein the pressure control component includes one or a plurality of through holes disposed within the pressure control component or between an outer periphery of the pressure control component and a body of the stopper so as to pass through from an upper end to a lower end between the pressure control component or the outer periphery of the pressure control component and the body of the stopper,
wherein the through hole has a diameter having a size between φ0.2 mm and φ2 mm both inclusive, the size being obtained by assuming a cross section of the hole as a circular shape and converting the cross section into a circle, and
wherein the number of through holes satisfies Equations 1 and 2:
(−0.44× Hd 2 +1.88 Hd− 0.08)≤ Ha≤{ 1.67×ln( Hd )+3.66}  Equation 1

Hn=Ha ÷( Hd 2 ×π÷4)  Equation 2, where

Ha is a numerical value of a total cross-sectional area of the through hole(s),
Hn is the number of through holes,
Hd is a numerical value of a diameter of the through hole, and
π is a circular constant,
with the total cross-sectional area measured in mm 2 and the diameter of the through hole measured in mm.

2. The stopper for continuous casting as claimed in claim 1 , wherein
the pressure control component is placed in an area below a diameter reduction starting position of a stopper distal end.

3. The stopper for continuous casting as claimed in claim 1 , wherein
the through hole has a slit shape (hereinafter referred to as “slit”), where a total cross-sectional area of the slit(s) is regarded as said Ha (mm 2 ) and a thickness of the slit is regarded as said Hd (mm), a value obtained by dividing the total cross-sectional area of the slit(s) by the thickness of the slit is a total length of the slit(s).

4. A continuous casting method using the stopper for continuous casting as claimed in claim 1 , the method comprising
A discharging gas into molten steel from the gas discharge hole of the stopper of claim 1 by setting gas pressure in the cavity on an upstream side of the pressure control component to a value between 2×10 −2 (MPa) and 8×10 −2 (MPa) both inclusive.

Assignees

• Krosakiharima Corp

Inventors

• Fukunaga Shinichi
• Kaku Toshio
• Furukawa Hiroki
• Okada Takuya

Classifications

• B22D41/186 Primary

  with means for injecting a fluid into the melt · CPC title

• B22D11/18

  for pouring (B22D11/20 takes precedence) · CPC title

• B22D41/18 Primary

  Stopper-rods therefor · CPC title