Today, I will introduce to you how to improve the purity of molten steel when we are rolling steel.
First of all, before the molten steel enters the mold, start from each process to minimize the pollution to the molten steel, and maximize the removal of inclusions from the molten steel.
The following measures should be taken for this purpose:
Slag-free tapping: The converter should block slag for tapping, and the electric furnace adopts eccentric bottom tapping to prevent steel slag from entering the ladle or ladle or tank.
According to the needs of steel grades, select the appropriate refining treatment method to improve the shape of inclusions with pure molten steel.
Adopt non-oxidative pouring technology. The oxygen content of the molten steel after refining treatment has been reduced to below 20×10-6; protective pouring is used in the ladle → tundish → mold; double-layer slag covering agent is used in the tundish to isolate the molten steel from the air to avoid steel Secondary oxidation of liquids.
Give full play to the role of the intermediate tank metallurgical purifier. Improve the flow of molten steel, eliminate the dead zone of the tundish; increase the capacity of the tundish and deepen the depth of the molten pool, prolong the residence time of the molten steel in the tundish, promote the floating of inclusions, and further purify the molten steel.
The continuous casting system selects refractory materials with high refractoriness, small melting loss and high quality to reduce foreign inclusions in the steel.
Play the role of the molten steel purifier of the mold and the surface quality controller of the slab. The selected immersion nozzle should have a reasonable opening shape and angle, control the movement of the injection flow, and promote the floating and separation of the inclusions; and supplemented by a mold flux with good performance, it can absorb and dissolve the floating inclusions to purify the molten steel.
Electromagnetic stirring technology is used to control the movement of the injection flow.
Calculations show that in a static state, the upward velocity of slag particles larger than 1 mm is about 100-200 cm/s; while the downward flow velocity of the injection stream is 60-10 cm/s; it can be seen that the inclusions float up in the impact area of the injection stream in the liquid phase cavity of the crystallizer. is difficult; some of the inclusions are likely to be trapped by solidified dendrites.
In fact, the inclusion content is often higher at 10 to 20 cm below the surface of the slab. The installation of electromagnetic brake can restrain the movement of injection flow, promote the floating of inclusions, and improve the purity of molten steel.
Luoyang Judian is a manufacturer of rolling mills. Welcome to pay attention to us. If you need it, you can contact us.