Electromagnetic stirring device and method for secondary cooling zone during slab continuous casting

Patent metadata

Field	Value
Publication number	US-11772153-B2
Application number	US-202017617663-A
Country	US
Kind code	B2
Filing date	Jun 10, 2020
Priority date	Jun 12, 2019
Publication date	Oct 3, 2023
Grant date	Oct 3, 2023

Abstract

An electromagnetic stirring device and a method for a secondary cooling zone during slab continuous casting. The device has a main body, an opening adjustment assembly, and a secondary cooling assembly. The main body has a protection housing (3), a phase sequence control assembly, an iron core (4) and an electromagnetic coil (5) for carrying out variable-direction electromagnetic stirring on a molten steel by a three-phase current phase sequence transformation. The opening adjustment assembly has an air cylinder (7), a fixed base (8), a movable joint shaft (12) and a silicon steel sheet group insert (13) for adjusting online opening degree of the closed annular iron core by a movable joint structure. The secondary cooling assembly has a cooling water inlet (9) and a cooling water nozzle (10) for cooling the electromagnetic coil and spraying cooling water to a surface of a cast slab (1).

First claim

The invention claimed is:

1. An electromagnetic stirring device for a secondary cooling zone of slab continuous casting comprises comprising a main body, an opening adjustment assembly, and a secondary cooling assembly, wherein
the main body of the electromagnetic stirring device comprises a protective shell ( 3 ), a phase sequence control assembly, an iron core ( 4 ), and an electromagnetic coil ( 5 ) disposed within the protective shell ( 3 ),
the opening adjustment assembly comprises a cylinder ( 7 ), a fixing base ( 8 ), a movable joint shaft ( 12 ) and multiple pieces of silicon steel sheet group inserts ( 13 ) that are sequentially connected by the movable joint shaft ( 12 ) to form multiple movable joints, wherein the silicon steel sheet group inserts ( 13 ) are rotatable around the movable joint shaft ( 12 ), and the multiple movable joints are connected with the iron core ( 4 ) to form a closed annular structure, wherein an electromagnetic coil ( 5 ) is wound on the iron core ( 4 ), and the electromagnetic coil ( 5 ) is operated by the phase sequence control assembly for generating an alternating magnetic field in a closed annular structure, and a casting slab ( 1 ) passes through an alternating magnetic field in the closed annular structure, and wherein the cylinder ( 7 ), which is fixedly installed on an outside of the main body of the electromagnetic stirring device through the fixing base, has a piston end connected with the main body of the electromagnetic stirring device and provides a driven force for opening and closing of the multiple movable joints, and
the secondary cooling assembly comprises a cooling water inlet ( 9 ) disposed at an end outside the protective shell ( 3 ) and multiple cooling water nozzles ( 10 ) spaced apart from each other and disposed at an end inside the protective shell ( 3 ) and facing the casting slab ( 1 ), cooling water is transmitted through the cooling water inlet ( 9 ) into the protective shell ( 3 ), wherein the electromagnetic coil ( 5 ) and the iron core ( 4 ) are immersed, and the cooling water is sprayed onto a surface of the casting slab ( 1 ) through the multiple cooling water nozzles ( 10 ).

2. The electromagnetic stirring device of claim 1 , wherein the main body of the electromagnetic stirring device is subjected to a stirring current frequency f 1 of 2 Hz to 15 Hz.

3. The electromagnetic stirring device of claim 1 , wherein the phase sequence control assembly comprises a water-cooled cable ( 6 ), an alternating phase conversion circuit, a fuse FU, and a disconnecting switch QS, wherein the water-cooled cable ( 6 ) comprises a first stirring current inlet line L 1 , a second stirring current inlet line L 2 , and a third stirring current inlet line L 3 , wherein one end of the first stirring current inlet line L 1 , one end of the second stirring current inlet line L 2 , and one end of the third stirring current inlet line L 3 are connected to a three-phase power supply, and wherein the other end of the first stirring current inlet line L 1 , the other end of the second stirring current inlet line L 2 , and the other end of the third stirring current inlet line L 3 are connected to the electromagnetic coil ( 5 ) via the disconnecting switch QS and the fuse FU.

4. The electromagnetic stirring device of claim 3 , wherein the alternating phase conversion circuit comprises a first contactor KM 1 , a second contactor KM 2 , an alternating voltage u 1 , a transformer T, a first diode D 1 , a second diode D 2 , and a resistor R, wherein the alternating voltage u 1 is connected to a primary of the transformer T, anodes of the first diode D 1 and the second diode D 2 are connected to a secondary output terminal of the transformer T, a cathode of the first diode D 1 is connected to a secondary input terminal of the transformer T through the first contactor KM 1 and the resistor R, and a cathode of the second diode D 2 is connected to the secondary input terminal of the transformer T through the second contactor KM 2 and the resistor R, the first contactor KM 1 and the second contactor KM 2 are connected to the electromagnetic coil ( 5 ), wherein a phase sequence by which the first contactor KM 1 is connected to the electromagnetic coil ( 5 ) is reversed to the phase sequence by which the second contactor KM 2 is connected to the electromagnetic coil ( 5 ), and an on-off of the first contactor KM 1 and the second contactor KM 2 are controlled by the alternating phase conversion circuit.

5. The electromagnetic stirring device of claim 4 , wherein the alternating voltage u 1 has a frequency f 2 of 0.1 Hz to 1 Hz.

6. The electromagnetic stirring device of claim 3 , wherein the phase sequence control assembly further comprises a thermal relay FR through which the first contactor KM 1 and the second contactor KM 2 are connected to the electromagnetic coil ( 5 ).

7. The electromagnetic stirring device of claim 1 , wherein the protective shell ( 3 ) comprises a tooth head end concaved inwardly at both sides to form cambered structures, wherein the tooth head end of the protective shell ( 3 ) extends toward the casting slab ( 1 ) and is arranged between two segmented rollers ( 2 ), and the cambered structures of the protective shell ( 3 ) match profiles of the segmented rollers ( 2 ).

8. The electromagnetic stirring device claim 1 , characterized in that wherein water sealing gaskets ( 11 ) are arranged at connections between both ends of a pair of iron cores ( 4 ) and the protective shell ( 3 ).

9. A method for electromagnetic stirring with the electromagnetic stirring device of claim 1 , wherein the method comprises the following steps:
a) driving the silicon steel sheet group insert ( 13 ) with the cylinder ( 7 ) to rotate around the movable joint shaft ( 12 ) and adjust an opening degree of the closed annular structure according to a thickness of the casting slab ( 1 ),
b) energizing the phase sequence control assembly through an alternating phase conversion circuit, wherein the electromagnetic coil ( 5 ) wound around the iron core ( 4 ) produces a periodically alternative magnetic field in the closed annular structure and electromagnetically stir a molten steel in a back-and-forth alternative mode, and
c) introducing cooling water into the protective shell ( 3 ) through the cooling water inlet ( 9 ) and immersing the electromagnetic coil ( 5 ) and the iron core ( 4 ), and spraying the cooling water onto the surface of the casting slab ( 1 ) through the multiple cooling water nozzles ( 10 ).

10. The method of claim 9 further comprising the following steps in b):
a) turning a first diode D 1 of the alternating phase conversion circuit to a forwardly conducting state and allowing a commutation current of positive half cycle to pass through a first contactor KM 1 of the phase sequence control assembly, energizing the first contactor KM 1 to work,
b) generating a magnetic field with the electromagnetic coil ( 5 ) wound around the iron core ( 4 ) and connecting a three-phase power supply to the electromagnetic stirring coil ( 5 ) with a phase sequence of U-V-W, wherein the molten steel is subjected to forward electromagnetic stirring,
c) turning a second diode D 2 of the alternating phase conversion circuit to a forward conducting state and allowing a commutation current of negative half cycle to pass through a second contactor KM 2 of the phase sequence control assembly, energizing the second contactor KM 2 to work,
d) generating a magnetic field with the electromagnetic coil ( 5 ) wound around the iron core ( 4 ) and connecting the three-phase power supply to the electromagnetic stirring coil ( 5 ) with a phase sequence of W-V-U, wherein the molten steel is subj

Assignees

• Baoshan Iron & Steel

Inventors

• Wen Hongquan
• Zhou Yueming
• Wu Cunyou
• Hu Chao
• Jin Xiaoli
• Zhao Xianjiu
• Wang Chunfeng

Classifications

• B22D11/115 Primary

  by using magnetic fields · CPC title

• B22D11/122 Primary

  using magnetic fields · CPC title

• B22D11/1246

  Nozzles; Spray heads · CPC title

• B22D11/225

  for secondary cooling · CPC title

• B22D11/205

  by using electric, magnetic, sonic or ultrasonic means · CPC title