Publish Time: 2021-06-08 Origin: Site
Hunan Zhongke Electric Co., Ltd., provides solution to improve the equiaxed grain ratio in continuous casting of steel. Through control on the overheat of molten steel, the casting speed, the secondary cooling water,and the mold electromagnetic stirrer, high quality products are ensured.Then, let's introduce in detail how to improve the equiaxed grain ratio?
Here is the content list:
l Electromagnetic stirring frequency
l Over-heat of the molten steel
l Casting strand
l Position of electromagnetic stirrer
l Current intensity
Toimprove the equiaxed grain ratio, the chemical weight percentage of steel is 0 . 6 5 % C：0.57%~ ,Si：0.17%~ 0 . 3 7 % ,Mn：0.4%~ , 0 . 8 %, Electromagnetic stirring frequency is 4.0-4.6Hz .
In terms of over-heat, when the temperature gradient of the front of the solid-liquid interface is low enough, the constituent over the cooling degree of the front of the solid-liquid interface will be greater than the over-cold temperature required by the shaped core. Low overheat favors the formation of low-temperature gradients, coupled with a large number of crystalline embryos stored in low overheat steel fluids, so it is very beneficial to improve the equiaxed grain ratio. Steel water overheat is 25 ~ 35℃.
Regarding the casting speed, if the casting speed is too high, the equiaxed grain will decrease, and the productivity will be low. The casting speed is 2.5~2.9m/min. And the specific water volume of secondary cooling is 0.9^1.2 L/kg0.
The installation position of EMS is very important. If the position is high, it may form a whirlpool on the molten metal surface, which will lead to improvingthe equiaxed grain ratio. So that the blocking of the mold powder decreases in the lubricating effect. The EMS is placed under the mold 18~22 mm. The defects of the billet are reduced and the meniscus is stable.
The frequency and current intensity of electromagnetic stirrer are also decisive parameters. The intensity of the electromagnetic stirring force is proportional to the magnetic induction intensity, so the change of electromagnetic stirring force with frequency is not monotonous, but improve the equiaxed grain ratioto the maximum electromagnetic stirring force is the best frequency.
When considering the electromagnetic stirring process parameters, we should also consider improve the equiaxed grain ratio. As if the current intensity is too low, it can not meet the requirements of the stirring process, while if the current intensity is too high, it's easy to roll up slag.Therefore, the optimal selection of electromagnetic stirring frequency and current intensity should be considered when considering the optimal parameters.
Through the above scheme, the equiaxed crystal rate of the billet can be steadily increased to more than 20%, and the high tensile speed also brings about the improvement of production efficiency. This not only ensures efficient production, but also improves the equiaxed grain ratio caused by the lack of equiaxed crystal rate in the past, and will not make the defects inherent to the rolling process.