The core wire must be added through a wire feeder during the deoxidation of molten steel calcium treatment in the ladle. The surface shapes of the wire feeder core wire that we often see are various, such as polygons, circles, rectangles, etc., while the shape of the internal wire feeder core wire is only circular. At present, a newly produced cored wire can be used not only for surface wire feeding, but also for internal wire feeding.
Its design philosophy is:
1. Cored wire core material
Alloy calcium cored wires, such as CaSi wires, can be obtained at low cost in industrial production, and the presence of Si improves the yield of calcium; Composite calcium cored wire, such as caf é wire, in which Fe is added to increase the density of the cored wire, making the calcium fed closer to the bottom of the ladle under the same conditions; The true deoxygenation effect is the calcium metal element. From the perspective of the interests of steel companies and the reputation of the core wire industry, it is recommended to use high-density reduced calcium core materials for core wire.
2. Sealing method of core wire
In surface wire feeding, both bite type and welding type can be used. But the bite type has a triangular like gap at the bite, which can introduce air into the steel liquid. Although top grooves can be added to reduce gaps, there is pre-stress in the core wire, which is prone to curling when heated. In internal wire feeding, the welding type has a better effect. Recommend the production and use of welded core wire.
3. Mass ratio of core material to shell of cored wire
If the external layer is too thin, the rigidity of the core wire will be weak, and the surface wire feeding will cause the liquid level to spiral and prevent it from entering the steel water; If the shell is too thick, the heat required for its melting will increase, and the temperature of the ladle will decrease. Therefore, we need to choose a moderate external thickness, usually between 0.6 and 0.7mm. When the external quality of the core material is high, the cost of calcium treatment will be greatly reduced. Experts recommend that the production and use of the core material should be 1 to 1.2 compared to the external quality