Alloy steel manufacturing method

Patent metadata

Field	Value
Publication number	US-2021262068-A1
Application number	US-201917261077-A
Country	US
Kind code	A1
Filing date	Jul 15, 2019
Priority date	Jul 23, 2018
Publication date	Aug 26, 2021
Grant date	—

Abstract

Provided is an alloy steel manufacturing method, the method including: preparing a manganese-containing first molten ferroalloy; preparing a chromium-containing second molten alloy; preparing molten steel; mixing the first molten ferroalloy and the second molten ferroalloy to manufacture third molten ferroalloy; and mix pouring the third molten ferroalloy and the molten steel to manufacture an alloy steel, wherein the phosphorous concentration in the molten steel may efficiently be controlled by reducing the converter end point temperature of the molten steel to improve a phosphorous control capacity during converter refining.

First claim

1 . An alloy steel manufacturing method comprising:
preparing a manganese-containing first molten ferroalloy; preparing a chromium-containing second molten ferroalloy; preparing molten steel; mixing the first molten ferroalloy and the second molten ferroalloy to manufacture third molten ferroalloy; and mixing the third molten ferroalloy and the molten steel in a molten state to manufacture alloy steel.

2 . The alloy steel manufacturing method of claim 1 , wherein the preparing of the first molten ferroalloy comprises:
melting, in a first melting furnace, a manganese-containing raw material to manufacture a first molten ferroalloy; charging the first molten ferroalloy into a first temperature holding furnace; and holding the first molten ferroalloy at a temperature no less than a melting point.

3 . The alloy steel manufacturing method of claim 2 comprising refining the first molten ferroalloy after the manufacturing of the first molten ferroalloy.

4 . The alloy steel manufacturing method of claim 3 , wherein the holding of the first molten ferroalloy at a temperature no less than a melting point comprises charging, into the first temperature holding furnace, at least any one among manganese metal having a smaller phosphorous (P) content than the first molten ferroalloy and molten manganese in which manganese metal is melted to reduce a phosphorous (P) concentration in the first molten ferroalloy and increase a manganese concentration in the first molten ferroalloy.

5 . The alloy steel manufacturing method of claim 4 , wherein the holding of the first molten ferroalloy at a temperature no less than a melting point comprises heating the first molten ferroalloy in the first temperature holding furnace.

6 . The alloy steel manufacturing method of claim 5 , wherein the preparing of the second molten ferroalloy comprises:
melting, in a second melting furnace, a chromium-containing raw material to manufacture a second molten ferroalloy; charging the second molten ferroalloy into a second temperature holding furnace; and holding the second molten ferroalloy at a temperature no less than a melting point.

7 . The alloy steel manufacturing method of claim 6 , comprising refining the second molten ferroalloy after the manufacturing of the second molten ferroalloy.

8 . The alloy steel manufacturing method of claim 7 , wherein the holding of the second molten ferroalloy at a temperature no less than a melting point comprises charging, into the second temperature holding furnace, at least any one among chromium metal having a smaller phosphorous (P) content than the second molten ferroalloy and molten chromium, in which chromium metal is melted, to reduce a phosphorous (P) concentration in the second molten ferroalloy and increase a chromium concentration in the second molten ferroalloy.

9 . The alloy steel manufacturing method of claim 8 , wherein the holding of the second molten ferroalloy at a temperature no less than a melting point comprises heating the second molten ferroalloy in the second temperature holding furnace.

10 . The alloy steel manufacturing method of claim 9 , wherein in the preparing of the first molten ferroalloy and the second molten ferroalloy, a phosphorous concentration in the first molten ferroalloy and the second molten ferroalloy is controlled to be approximately 350 ppm or less so that the phosphorous concentration in the alloy steel is approximately 140 ppm or less.

11 . The alloy steel manufacturing method of claim 10 , wherein the manufacturing of the third molten ferroalloy comprises:
discharging the first molten ferroalloy stored in the first temperature holding furnace to a mixing container; and discharging the second molten ferroalloy stored in the second temperature holding furnace to the mixing container, wherein the second molten ferroalloy is discharged earlier than the first molten ferroalloy.

12 . The alloy steel manufacturing method of claim 11 , wherein the manufacturing of the third molten ferroalloy is performed by mixing the first molten ferroalloy and the second molten ferroalloy so that a manganese components and a chromium components in the third molten ferroalloy have a ratio of approximately 6:1 to approximately 14:1.

13 . The alloy steel manufacturing method of claim 12 , wherein the manufacturing of the third molten ferroalloy is performed by mixing the first molten ferroalloy and the second molten ferroalloy so that a manganese content is approximately 24 wt % or more and a chromium content is approximately 3 wt % or more with respect to a total weight of the alloy steel.

14 . The alloy steel manufacturing method of claim 13 , wherein the manufacturing of the third molten ferroalloy comprises:
measuring, as concentration, the manganese content and the chromium content in the third molten ferroalloy; and further discharging, to the mixing container, at least any one among the first molten ferroalloy and the second molten ferroalloy according to a measured result.

15 . The alloy steel manufacturing method of claim 14 , wherein in the preparing of the molten steel, a temperature of the molten steel is approximately 1,600-1,700° C.

Assignees

• Posco

Inventors

• Han Woong Hee
• Yun Yeo Sun
• Kang Soo Chang
• Son Jung Hwan

Classifications

• C22C38/38

  with more than 1.5% by weight of manganese · CPC title

• C22C33/04 Primary

  by melting · CPC title

• C22C33/06 Primary

  using master alloys · CPC title

• C21C7/0006

  Adding metallic additives · CPC title

• C22C1/02

  by melting {(C22C1/1036 takes precedence)} · CPC title