Powdered wire is mainly made from ribbon and alloy powder by mechanical pressing. The amount of cored wire decreases with increasing calcium yield and depends on the type of cored wire and varies considerably. Under the condition of the same degree of calcium extraction, the mass fraction of calcium in pure calcium powder wire is higher, and the advantage of quantity is obvious.
Calcium treatment of steel and the choice of cored wire. Traditional powder wires used for calcium treatment mainly include:
1. calcium-silicon wire: the powder in the wire is Si-Ca alloy. The advantage is that the calcium absorption rate is stable, and calcium is not easily oxidised by air. The disadvantage is the serious increase of silicon content, and it is not applicable to low-silicon steel.
2. Calcium-iron wire: the powder inside the wire core is pure calcium metal particles, which are mixed with iron powder in a certain proportion, but in the process of feeding, a lot of smoke is produced, which easily leads to steel spattering, the recovery rate of calcium is not stable, and the calcium metal is easily oxidised by moisture, which shortens the shelf life of the wire.
3. Calcium aluminium wire: The powder inside the wire can be made of CaAl alloy by crushing or by mechanically mixing pure calcium particles with aluminium powder. This line is characterised by stable and high calcium recovery rate, and there is no obvious increase of silicon in the steel after wire feeding.