Method for producing alloy steel

Patent metadata

Field	Value
Publication number	US-2020377977-A1
Application number	US-201716330600-A
Country	US
Kind code	A1
Filing date	Sep 4, 2017
Priority date	Sep 6, 2016
Publication date	Dec 3, 2020
Grant date	—

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.

First claim

1 . 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



%

)

-

Assignees

• Posco

Inventors

• Kang Soo Chang
• Ahn Chong Tae
• Han Woong Hee
• Beak Jun Jeong
• Song Min Ho

Classifications

• C21C2300/06

  Modeling of the process, e.g. for control purposes; CII · CPC title

• C21C5/5264

  Manufacture of alloyed steels including ferro-alloys · CPC title

• Y02P10/25

  Process efficiency · CPC title

• C21C7/072 Primary

  Treatment with gases (C21C7/06, C21C7/064, C21C7/068 take precedence) · CPC title

• C22C38/001

  containing N · CPC title