Publish Time: 2021-09-06 Origin: Site
The electromagnetic stirring for continuous casting has become a necessary process for high efficiency and quality continuous casting, which can effectively improve the internal structure of casting strand, as well as reduce center segregation, eliminate center shrinkage and increase exquiaxed grain ratio.
The strand electromagnetic stirrer（S-EMS）can not only generate exquiaxed grain, but also homogenize the solute composition in the center of the strand, thereby minimizing the center segregation of the casting strand.
Here is the content:
Working principle of the slab strand electromagnetic stirrer(S-EMS)
General types and features of slab strand electromagnetic stirrer(S-EMS)
In-roll electromagnetic stirring technology with high magnetic intensity
Metallurgical effect
A pair of traveling wave magnetic field electromagnetic stirrers installed face to face at a suitable position in the secondary cooling zone of the slab. An alternating magnetic field B corresponding to the N-S pole will be generated, and it moves in the same direction at a certain speed (traveling wave magnetic field). The traveling wave magnetic field B will induce an induced current in the strand, and this current will interact with the traveling wave magnetic field B to generate electromagnetic force F in the molten steel of the strand. The direction of F is always the same as that of the traveling wave magnetic field. (Please see Fig.1)
Fig.1 Working principle of electromagnetic stirrer
The electromagnetic force F pushes the molten steel in the casting strand to move from one narrow surface of the casting strand to the other one. When the moving molten steel hits the narrow surface, it will form a loop up and down along the drawing direction, thereby forming a butterfly-shaped stirring field. The upper and lower stirring area is about 2-3 times the width of the plate. (See Fig. 2)
Fig.2 Flow field of the stirred molten steel
There are 3 types of slab strand electromagnetic stirrer(S-EMS), and the main technical features are as follows:
Type | Magnetic pole inserted | Rear roller | Roller type (EMS roller with high magnetic force) |
Quantity of coil | 2 pieces installed face to face to form a pair | 1 piece installed at single side | 4 pieces of roller forming 2 pairs |
Inductor winding | Copper tube winding, Cramer type | Cooper tube winding, Iterative type | Flat cooper wire winding, Cramer type |
Current | 2×700A | 2000A以上 Above 2000A | 2×400A |
Central electromagnetic thrust | 100 mmFe | 35-60 mmFe | 1 pair：60 -80 mmFe; 2 pairs in parallel:100-120 mmFe |
Effect side | Both inner and outer arc | Single side | Both inner and outer arc |
Installation position | Can be installed at Seg.1 to Seg.6. | Suitable to be installed at straight arc area, but the position cannot be adjusted |
Can be installed at the end of straight arc and Seg.1 to Seg.6. |
Modification on segment | Special segment is required. The structure of the roller row needs to be changed. | The structure of the roller row remains unchanged, but the structure of the continuous caster needs to be changed. | Almost no changes to the segment and the continuous caster structure. |
Advantages | With high electromagnetic intensity, it can be applied for stirring of various steel grades; The installation position can be adjusted flexibly according to different steel grades; Long service life. | The structure of roller row remains unchanged; The service life is long. | With high electromagnetic intensity, it can be applied for stirring of major steel grades; 2 pairs installed in parallel can applied for the stirring of all steel grades; The installation position can be adjusted flexibly according to various steel grades. |
Disadvantages | The segment needs to be customized; The roller distance increased; Causes bulging. | Low electromagnetic intensity; The installation position can not be adjusted. | The service life is not long; The maintenance is inconvenient. |
The E-shaped iron core is designed to be a cylindrical iron core without cogging, and a magnetic shielding ring is installed on the sides other than the working surface of the electromagnetic stirring roller. The typical structure is shown in the as following Figure (please see Fig.3)
1: Magnetism shielding ring; 2: Winding; 3: Cylindrical iron core
Fig.3 Typical structure
Changing the E-shaped iron core to a cylindrical iron core without cogging can maximize the space utilization of the winding and increase the magnetic area of the iron core, thereby increasing the strength of the magnetic field and increasing the electromagnetic intensity.
Adding a magnetic shielding ring on the sides of the electromagnetic stirring roller other than the working surface can prevent the magnetism from leaking from the reactive direction, thereby greatly increasing the magnetic field strength of the working surface and increasing the electromagnetic intensity.
Silicon steel
In addition to the in-roll EMS, Zhongke Electric also provides lifting magnet, induction heater for tundish, cable reel, etc. We are glad to provide you with our products of good quality and best service.