US 2026/0258518 A1Published application

Method for deoxidation refining of molten steel, method for producing steel material, and steel material thereof

AssigneeJfe Steel Corporation

InventorsKeisuke MIZOBATA, Hidemitsu NEGISHI, Takeshi AKESHI MURAI

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Abstract

A method for deoxidation refining of molten steel using a vacuum refining equipment, in which an Al-containing substance is added to molten steel inside a vacuum vessel, and deoxidation refining of the molten steel is performed in such a manner that temperature changes ΔT1 and ΔT2 of the molten steel during Al deoxidation meet Formula (1). Performing this method for deoxidation refining of molten steel as a deoxidation step can produce a steel material in which the range of the Al concentration in steel after the deoxidation step is 0.02 mass % or less. ΔT1+ΔT2<0 . . . (1), where ΔT1 represents an amount of temperature rise due to the heat of an oxidation reaction of Al, and ΔT2 represents an amount of temperature drop due to the sensible heat of the Al-containing substance added.

Claims8

Dependent claims

A method for deoxidation refining of molten steel using a vacuum refining equipment,

wherein
an Al-containing substance is added to molten steel inside a vacuum vessel, and that temperature changes ΔT1 and ΔT2 of the molten steel during Al deoxidation meet Formula (1):
Δ
⁢
T
1
+
Δ
⁢
T
2
<
0
,
(
1
)
where ΔT1 and ΔT2 are temperature changes (° C.) respectively defined by:
Δ
⁢
T
1
=
(
W
Re
⁢
_
⁢
Al
×
Q
Al
-
O
)
/
(
C
steel
×
W
Re
⁢
_
⁢
STEEL
)
(
2
)
Δ
⁢
T
2
=
-
(
V
Al
/
0.01
⁢
X
Al
×
t
1
×
Q
Al
⁢
_
⁢
Alloy
-
C
)
/
(
C
steel
×
W
Re
⁢
_
⁢
STEEL
)
,
(
3
)
t1 is a time(s) elapsed from when addition of the Al-containing substance is started until the molten steel present inside the vacuum vessel at the start of addition of the Al-containing substance has circulated and become displaced,
WRe_Al is mass (kg) of metallic Al used for a deoxidation reaction during the time t1,
QAl—O is heat (kJ/kg-Al) of an oxidation reaction of Al,
Csteel is specific heat (kJ/kg/° C.) of the molten steel,
WRe_STEEL is mass (kg) of molten steel used for the deoxidation reaction during the time t1,
VAl is an addition rate (kg/s) of metallic Al,
XAl is an Al content (mass %) in the Al-containing substance, and
QAl_Alloy-C is sensible heat and latent heat (kJ/kg) of the Al-containing substance.

99 more elements

Dependencies are inferred from the claim text.