Carburizer and carburization method using the same

Patent metadata

Field	Value
Publication number	US-2026043120-A1
Application number	US-202519366530-A
Country	US
Kind code	A1
Filing date	Oct 23, 2025
Priority date	Dec 7, 2018
Publication date	Feb 12, 2026
Grant date	—

Abstract

A carburizer, which effects carburization with respect to molten iron accommodated in an electric furnace or a ladle, includes a mixture of quicklime and a carbon material having an ash content of from 5 mass % to 18 mass %, and satisfies the conditions 0.6≤(mc+Mc)/ms≤2.7 and 0.7≤(mc+Mc)/ma≤6.5. A method of carburization uses this carburizer. Here, mc represents the mass of CaO in the carbon material, ms represents the mass of SiO 2 in the carbon material, ma represents the mass of Al 2 O 3 in the carbon material, and Mc represents the mass of the quicklime.

First claim

1 . A method of carburization, comprising, in an electric furnace or a ladle, performing carburization by adding a carburizer to a molten iron surface formed by blowing in a gas and agitating the molten iron,
the carburizer comprising a mixture of quicklime and a carbon material having an ash content of from 5 mass % to 18 mass %, and the carburizer satisfying conditions stipulated in the following Formula (1) and Formula (2):

0
.
6

≤

(

mc
+
Mc

)

/
ms

≤
2.7

Formula
⁢

(
1
)

0.7
≤

(

mc
+
Mc

)

/
ma

≤

6
.
5

Formula
⁢

(
2
)

wherein, in Formula (1) and Formula (2), mc represents a mass of CaO in the carbon material, ms represents a mass of SiO 2 in the carbon material, ma represents a mass of Al 2 O 3 in the carbon material, and Mc represents a mass of the quicklime.

2 . The method of carburization recited in claim 1 , wherein the mixture satisfies conditions stipulated in the following Formula (1A) and Formula (2A):

0
.
6

≤

(

mc
+
Mc

)

/
ms

≤
1.9

Formula
⁢

(

1
⁢
A

)

0.7
≤

(

mc
+
Mc

)

/
ma

≤

5.
.

Formula
⁢

(

2
⁢
A

)

3 . The method of carburization recited in claim 1 , wherein the carburizer is added by being fed towards the molten iron surface from a lance.

4 . The method of carburization recited in claim 1 , wherein the carburizer is a briquette.

5 . The method of carburization recited in claim 1 , wherein a maximum particle size of the carbon material is 20 mm or less.

6 . The method of carburization recited in claim 1 , wherein the carbon material is coal containing 10% or more of volatile matter and has a maximum particle size of 100 mm or less.

7 . The method of carburization recited in claim 1 , wherein a maximum particle size of the quicklime is 10 mm or less.

8 . The method of carburization recited in claim 1 , wherein S concentration in the molten iron is 0.5 mass % or less.

Assignees

• Nippon Steel Corp

Inventors

• Muneoka Hitoshi
• Asahara Norifumi
• Sakamoto Motohiro
• Yamazaki Tsuyoshi

Classifications

• C21C5/52

  Manufacture of steel in electric furnaces {(C21C5/005 takes precedence)} · CPC title

• C21C7/0037

  by injecting powdered material · CPC title

• C21C5/527

  Charging of the electric furnace · CPC title

• Y02P10/20

  Recycling · CPC title

• C23C8/80

  After-treatment · CPC title