Method and stirring system for controlling an electromagnetic stirrer

Patent metadata

Field	Value
Publication number	US-10919088-B2
Application number	US-201816482585-A
Country	US
Kind code	B2
Filing date	Jan 23, 2018
Priority date	Feb 20, 2017
Publication date	Feb 16, 2021
Grant date	Feb 16, 2021

Abstract

A method of controlling an electromagnetic stirrer arranged around a submerged entry nozzle (SEN) of a tundish provided with a stopper rod to control throughput of the tundish, the SEN being configured to provide tapping of molten metal from the tundish and the electromagnetic stirrer being configured to generate a rotating magnetic field in the SEN, wherein the method includes controlling the electromagnetic stirrer to operate only when a gas flow rate through the stopper rod is in a first range of 1.5 NL/min to 20 NL/min.

First claim

The invention claimed is:

1. A method of controlling an electromagnetic stirrer arranged around a submerged entry nozzle (SEN) of a tundish provided with a stopper rod to control a casting throughput of the tundish, the SEN being configured to provide tapping of molten metal from the tundish and the electromagnetic stirrer being configured to generate a rotating magnetic field in the SEN, wherein the method comprises:
controlling the electromagnetic stirrer to operate only when a gas flow rate through the stopper rod is in a first range of 1.5 NL/min to 20 NL/min.

2. The method as claimed in claim 1 , wherein the first range is 2 NL/min to 15 NL/min.

3. The method as claimed in claim 2 , wherein in addition to the gas flow rate through the stopper rod being in the first range, the controlling involves controlling the electromagnetic stirrer to operate only when the casting throughput is at least 1.5 ton/min.

4. The method as claimed in claim 2 , comprising, prior to the step of controlling, obtaining a gas flow rate through the stopper rod, wherein the controlling is based on the obtained gas flow rate.

5. The method as claimed in claim 2 , wherein the controlling of the electromagnetic stirrer involves providing a controlled sub-meniscus speed of molten metal in a mold in a second range of 0.20 m/s to 0.50 m/s.

6. The method as claimed in claim 1 , wherein in addition to the gas flow rate through the stopper rod being in the first range, the controlling involves controlling the electromagnetic stirrer to operate only when the casting throughput is at least 1.5 ton/min.

7. The method as claimed in claim 6 , wherein the controlling involves controlling the electromagnetic stirrer to operate only when the casting throughput is at least 1.8 ton/min.

8. The method as claimed in claim 1 , comprising, prior to the step of controlling, obtaining a gas flow rate through the stopper rod, wherein the controlling is based on the obtained gas flow rate.

9. The method as claimed in claim 1 , comprising obtaining a sub-meniscus speed of molten metal in a mold, wherein the controlling is based on the obtained sub-meniscus speed.

10. The method as claimed in claim 9 , wherein the controlling of the electromagnetic stirrer involves providing a controlled sub-meniscus speed of molten metal in the mold in a second range of 0.20 m/s to 0.50 m/s.

11. The method as claimed in claim 10 , wherein the second range is 0.25 m/s to 0.45 m/s.

12. The method as claimed in claim 1 , wherein argon gas flows through the stopper rod.

13. A stirring system for a metal-making process, comprising:
an electromagnetic stirrer configured to be arranged around a submerged entry nozzle (SEN) of a tundish provided with a stopper rod to control a casting throughput of the tundish, and
a control system configured to control the electromagnetic stirrer to operate only when a gas flow rate through the stopper rod is in a first range of 1.5 NL/min to 20 NL/min.

14. The stirring system as claimed in 10 , wherein the first range is 2 NL/min to 15 NL/min.

15. The stirring system as claimed in claim 13 , wherein in addition to the gas flow rate through the stopper rod being in the first range, the control system is configured to control the electromagnetic stirrer to operate only when the casting throughput is at least 1.5 ton/min.

16. The stirring system as claimed in claim 15 , wherein the control system is configured to control the electromagnetic stirrer to operate only when the casting throughput is at least 1.8 ton/min.

17. The stirring system as claimed in claim 13 , wherein the control system is configured to control the electromagnetic stirrer to provide a controlled sub-meniscus speed of molten metal in a mold in a second range of 0.20 m/s to 0.50 m/s.

18. The stirring system as claimed in claim 17 , wherein the second range is 0.25 m/s to 0.45 m/s.

Assignees

• Abb Schweiz Ag
• Arcelormittal

Inventors

• Rydholm Bengt
• Sandberg Fredrik
• Yang Hongliang
• Eriksson Jan-Erik
• Galpin Jean-Marie
• Langlet Bruno
• Curé Jean-Luc
• Triolet Nicolas
• Lecoester Thierry

Classifications

• B22D41/62 Primary

  with stirring or vibrating means · CPC title

• B22D41/58

  with gas injecting means · CPC title

• B22D41/186

  with means for injecting a fluid into the melt · CPC title

• B22D11/115

  by using magnetic fields · CPC title

• B22D11/10

  Supplying or treating molten metal (B22D41/00 takes precedence) · CPC title