Mold flux for continuous-casting steel

Patent metadata

Field	Value
Publication number	US-10315245-B2
Application number	US-201415509207-A
Country	US
Kind code	B2
Filing date	Sep 11, 2014
Priority date	Sep 11, 2014
Publication date	Jun 11, 2019
Grant date	Jun 11, 2019

Abstract

Provided is mold flux that can prevent longitudinal cracks from forming on a surface of a slab upon continuous-casting hypo-peritectic steel, wherein CaO, SiO 2 , an alkali metal oxide and a fluorine compound are contained, 1.1≤(CaO) h /(SiO 2 ) h ≤1.9, 0.10≤(CaF 2 ) h /((CaO) h +(SiO 2 ) h +(CaF 2 ) h )≤0.40 and 0≤(alkali metal fluoride) h /((CaO) h +(SiO 2 ) h +(alkali metal fluoride) h )≤0.10 are satisfied, a solidification temperature is no less than 1300° C., and viscosity at 1450° C. is no more than 0.1 Pa·s.

First claim

The invention claimed is:

1. Mold flux used for continuous-casting hypo-peritectic steel whose C concentration is 0.08 to 0.18 mass %, wherein
CaO, SiO 2 , an alkali metal oxide and a fluorine compound are contained,
the following formulas (1), (2) and (3) are satisfied, and
a solidification temperature is no less than 1300° C. and viscosity at 1450° C. is no more than 0.1 Pa·s:
1.1≤ f (1)≤1.9  (1)

0.10≤ f (2)≤0.40  (2)

0≤ f (3)≤0.10  (3)

wherein f (1)=(CaO) h /(SiO 2 ) h   (a)

f (2)=(CaF 2 ) h /((CaO) h +(SiO 2 ) h +(CaF 2 ) h )  (b)

f (3)=(alkali metal fluoride) h /((CaO) h +(SiO 2 ) h +(alkali metal fluoride) h )  (c)

(CaO)h=(W CaO −(CaF 2 ) h ×0.718)  (A)

(SiO 2 ) h =W SiO2   (B)

(CaF 2 ) h =(W F −W Li2O ×1.27−W Na2O ×0.613−W K2O ×0.403)×2.05  (C)

(alkali metal fluoride) h =W Li2O ×1.74+W Na2O ×1.35+W K2O ×1.23  (D)

wherein W i is a mass concentration of a component i in the mold flux and (CaO) h , (SiO 2 ) h , (CaF 2 ) h , and (alkali metal fluoride) h represent values based on results from calculations from the right side of equations (A), (C), and (D), and the right side of equality (B).

2. The mold flux for continuous-casting hypo-peritectic steel according to claim 1 , wherein the mold flux further contains 0.1-10 mass % of MnO.

Assignees

• Nippon Steel & Sumitomo Metal Corp

Inventors

• Hanao Masahito

Classifications

• B22D11/111

  by using protecting powders · CPC title

• B22D11/001 Primary

  of specific alloys · CPC title

• C22C38/002

  containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60 · CPC title

• C03C2204/00

  Glasses, glazes or enamels with special properties · CPC title

• C22C38/04

  containing manganese · CPC title