Molten steel treatment apparatus and molten steel treatment method

Patent metadata

Field	Value
Publication number	US-9927177-B2
Application number	US-201315036196-A
Country	US
Kind code	B2
Filing date	Dec 24, 2013
Priority date	Dec 6, 2013
Publication date	Mar 27, 2018
Grant date	Mar 27, 2018

Abstract

Provided are a molten steel treatment apparatus and a molten steel treatment method capable of quickly measuring an inclusion adhesion state inside a nozzle during an operation. The molten steel treatment apparatus includes a container, a nozzle equipped in a molten steel tap hole of the container, a liner disposed on a portion of an inner circumferential surface of the nozzle and formed of an ion-conductive material, a power supply for applying electric power to the molten steel and the liner, and a measuring unit for measuring a voltage value or a current value between the molten steel and the liner. The molten steel treatment method includes measuring a voltage value or current value between the molten steel and the liner; and determining a thickness of an inclusion adhering to an interface between the molten steel and the liner by using the voltage value or the current value.

First claim

The invention claimed is:

1. A molten steel treatment apparatus comprising:
a container having a space for receiving molten steel and a molten steel tap hole formed in a bottom surface thereof so as to tap the molten steel;
a nozzle equipped in the molten steel tap hole and having an inner space through which the molten steel passes;
a slide gate equipped in the nozzle and configured to control a tap rate of the molten steel;
a liner installed on at least a portion of an inner circumferential surface of the nozzle, the liner being formed of an ion-conductive material;
a power supply for applying an electric power to the molten steel and the liner; and
a measuring unit configured to measure a voltage value or a current value between the molten steel and the liner and calculate a resistance value of an interface between the molten steel and the liner,
wherein the measuring unit is further configured to compare the measured voltage value with a preset reference voltage value, the measure current value with a preset reference current value, or the calculated resistance value with a preset reference resistance value, and determine an adhesion of inclusion to the interface and a thickness of the inclusion adhering to the interface using a result of the comparison,
wherein the slide gate is configured to increase the tap rate of the molten steel when determined that an inclusion is adhered to the interface, or
wherein the power supply is configured to increase a current value being applied between the molten steel and the liner when determined that an inclusion is adhered to the interface.

2. The molten steel treatment apparatus of claim 1 , wherein the electric power includes a DC current or a DC voltage.

3. The molten steel treatment apparatus of claim 1 , wherein the ion-conductive material comprises a solid electrolyte.

4. The molten steel treatment apparatus of claim 1 , further comprising a liner electrode disposed between the nozzle and the liner, wherein the electric power is applied to the liner through the liner electrode.

5. The molten steel treatment apparatus of claim 4 , wherein the power supply comprises a DC power source capable of applying a DC current or a DC voltage, wherein a negative terminal of the DC power source is connected to the molten steel, and a positive terminal of the DC power source is connected to the liner electrode.

6. The molten steel treatment apparatus of claim 1 , wherein the nozzle contains an electrically conductive material, and the power supply comprises a DC power source capable of applying a DC current or a DC voltage, wherein a negative terminal of the DC power source is connected to the molten steel, and a positive terminal of the DC power source is connected to the nozzle.

7. The molten steel treatment apparatus of claim 1 , wherein the measuring unit comprises:
a measuring part connected to the power supply and configured to measure the voltage value or the current value;
an arithmetic part connected to the measuring part, and configured to calculate the resistance value; and
a determination part connected to the arithmetic part and configured to determine the adhesion of inclusion and the thickness.

8. A molten steel treatment method comprising:
preparing molten steel in a container, the container having a molten steel tap hole formed in a bottom surface thereof;
tapping the molten steel through a nozzle attached to the molten steel tap hole;
applying an electric power to the molten steel and a liner disposed on an inner circumferential surface of the nozzle;
measuring a voltage value or a current value between the molten steel and the liner;
calculating a resistance value of an interface between the molten steel and the liner by using the measured voltage value or the measured current value;
determining that an inclusion is adhered to the interface when the measured voltage value is equal to or more than a preset reference value, the measured current value is equal to or less than a preset reference current value, or the calculated resistance value is equal to or more than a preset reference resistance value;
comparing the measured voltage value with the preset reference voltage value, the measure current value with the preset reference current value, or the calculated resistance value with the preset reference resistance value, and determining a thickness of the inclusion using a result of the comparison; and
increasing a tap rate of the molten steel or a current value being applied between the molten steel and the liner when determined that an inclusion is adhered to the interface.

9. The molten steel treatment method of claim 8 , wherein the electric power comprises a DC current or a DC voltage.

10. The molten steel treatment method of claim 9 , wherein the measuring comprises: measuring the voltage value when the electric power is the DC current, or measuring the current value when the electric power is the DC voltage.

Assignees

• Posco

Inventors

• Kim Wook

Classifications

• B22D41/50

  Pouring-nozzles · CPC title

• F27M2001/02

  Charges containing ferrous elements · CPC title

• B22D11/11

  Treating the molten metal · CPC title

• F27D21/00 Primary

  Arrangement of monitoring devices; Arrangement of safety devices · CPC title

• C21C7/00

  Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00 (treating molten metals during moulding B22D1/00, B22D27/00) · CPC title