US2020377977A1PendingUtilityA1
Method for producing alloy steel
Est. expirySep 6, 2036(~10.1 yrs left)· nominal 20-yr term from priority
C21C 2300/06C21C 5/5264Y02P10/25C21C 7/072C22C 38/001C22C 38/18C21C 2007/0093C21C 7/0006C21C 2300/08C22C 38/06C22C 38/04C21C 7/0075B22D 1/002C22C 38/00B22D 7/02C22C 33/04Y02P10/20
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Claims
Abstract
Provided is a method for producing steel including: preparing a first molten steel and a manganese-containing melt; supplying a nitrogen gas into a storage to blow nitrogen into the melt received in the storage and thereby adjusting a nitrogen content (wt %) in the melt to a required nitrogen content (wt %); and mixing the melt and the first molten steel to produce a second molten steel containing manganese and nitrogen. Since nitrogen is not blown while melting large amounts of solid materials, the oxidation of manganese due to a high temperature may be minimized or prevented. In addition, a large amount of solid material is not added, and a small amount of manganese-containing nonferrous metal or a FeMn ferroalloy is added, if necessary, into a produced melt in a molten state, and thus, a problem of temperature drop due to the input of the solid material may be minimized or prevented.
Claims
exact text as granted — not AI-modified1 . A method for producing steel, the method comprising:
preparing a first molten steel and a manganese-containing melt; supplying a nitrogen gas into a storage to blow nitrogen into the melt received in the storage and thereby adjusting a nitrogen content (wt %) in the melt to a required nitrogen content (wt %); and mixing the melt and the first molten steel to produce a second molten steel containing manganese and nitrogen.
2 . The method of claim 1 , wherein the adjusting the nitrogen content (wt %) in the melt to the required nitrogen content (wt %) comprises:
calculating a required nitrogen content (T) required for the second molten steel by using a second molten steel amount (T) which is a target producing amount of the second molten steel, and a target nitrogen content (wt %) of the second molten steel to be mixed; calculating the required nitrogen content (wt %) required for the melt in order to produce the second molten steel by using the required nitrogen amount (T) required for the second molten steel and a mixing amount (T) of the melt; deriving at least one among a melt temperature, a carbon (C) content (wt %) in the melt, a chromium (Cr) content (wt %) in the melt, or an aluminum (Al) content (wt %) in the melt in order to satisfy the calculated required nitrogen content (wt %); and adjusting the melt so as to satisfy the derived melt temperature while blowing nitrogen into the melt inside the storage, and adjusting at least one of the chromium (Cr) content (wt %) in the melt or the aluminum (Al) content (wt %) in the melt so as to satisfy the derived chromium (Cr) content (wt %) in the melt and the derived aluminum (Al) content (wt %) in the melt.
3 . The method of claim 2 , wherein in the calculating the required nitrogen amount required for the second molten steel, Equation 1 is used,
Required
nitrogen
amount
of
second
molten
steel
(
T
)
=
Amount
of
second
molten
steel
(
T
)
×
Target
nitrogen
content
of
second
molten
steel
(
wt
%
)
-
0.01
(
wt
%
)
100
(
wt
%
)
,
[
Equation
1
]
and
in
calculating
the
nitrogen
content
(
wt
%
)
required
for
the
melt
,
Equation
2
is
used
,
Required
nitrogen
amount
in
melt
(
wt
%
)
=
Required
nitrogen
amount
of
second
molten
steel
(
T
)
)
Melt
mixing
amount
(
T
)
×
100
(
wt
%
)
.
[
Equation
2
]
4 . The method of claim 3 , comprising calculating the mixing amount (T) of the melt by using a mixing amount (T) of the first molten steel, a target manganese content (wt %) in the second molten steel, and a manganese content (wt %) in the melt.
5 . The method of claim 4 , wherein in calculating the mixing amount (T) of the melt, Equation 3 is used,
Melt
mixing
amount
(
T
)
=
(
Amount
of
second
molten
steel
(
T
)
×
Target
manganese
content
of
second
molten
steel
(
wt
%
)
100
Manganese
content
in
melt
(
wt
%
)
100
)
-
Solid
manganese
add
amount
(
T
)
.
[
Equation
3
]
6 . The method of claim 4 , wherein in the deriving at least one among a melt temperature, a carbon (C) content (wt %) in the melt, a chromium (Cr) content (wt %) in the melt, or an aluminum (Al) content (wt %) in the melt, Equation 4 is used,
Required nitrogen content in melt (wt %)=(3.95−2.09 10 −8 )×Melt temperature (° C.)×(0.15×Carbon (C) content (wt %) in melt)+(0.093×(Chromium (Cr) content (wt %) in melt)+(0.14×Aluminum (Al) content (wt %) in melt).
7 . The method of claim 6 , wherein
in the adjusting of the melt temperature and the carbon (C) content (wt %) so as to satisfy the derived temperature of the manganese-containing melt and the derived carbon (C) content (wt %), and in adjusting of the chromium (Cr) content (wt %) in the melt or the aluminum (Al) content (wt %) in the melt so as to satisfy at least one of the derived chromium (Cr) content (wt %) and the derived aluminum (Al) content (wt %), the temperature of the manganese-containing melt is adjusted to the manganese-containing melt temperature derived by raising or maintaining the melt temperature inside the storage while blowing nitrogen into the storage; and when the carbon (C) content (wt %) is derived in order to satisfy the required nitrogen content (wt %) required for the melt, in the preparing of the manganese-containing melt, the melt is adjusted so as to satisfy the derived carbon (C) content (wt %), and each content (wt %) of the chromium (Cr) content (wt %) and the aluminum (Al) content (wt %) in the melt is adjusted by inputting a chromium (Cr)-containing material and a aluminum (Al)-containing material into the storage.
8 . The method of claim 7 , wherein
when the calculated nitrogen content required for the melt is less than 1 wt %, at least one of the melt temperature and the carbon (C) content (wt %) in the melt is adjusted, and when the calculated nitrogen content required for the melt is no less than 1 wt %, at least one of the chromium (Cr) content (wt %) in the melt and the aluminum (Al) content (wt %) in the melt is adjusted.
9 . The method of claim 5 , wherein in the mixing of the nitrogen-blown melt and the first molten steel, the melt having the nitrogen content adjusted to the required nitrogen content (wt %) in the storage is mixed with the first molten steel in the mixing amount (T) of the melt calculated by Equation 3.
10 . The method of claim 9 , comprising:
measuring the nitrogen content (wt %) of the second molten steel produced by mixing the melt and the first molten steel; comparing the measured nitrogen content (wt %) of the second molten steel with the target nitrogen content (wt %); starting casting using the second molten steel when the measured nitrogen content (wt %) of the second molten steel satisfies the target nitrogen content (wt %); and further adjusting the nitrogen content (wt %) when the measured nitrogen content (wt %) of the second molten steel does not satisfy the target nitrogen content (wt %).
11 . The method of claim 9 , wherein the further adjusting of the nitrogen content (wt %) comprises:
inputting an nitrogen-containing alloy when the measured nitrogen content (wt %) of the second molten steel is lower than the target nitrogen content (wt %) is performed; and degassing of the second molten steel is performed when the measured nitrogen content (wt %) of the second molten steel is higher than the target nitrogen content (wt %).Join the waitlist — get patent alerts
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