CAS Units*

In this process the alloying additions are made to the slag free steel surface under exclusion of air within a partially immersed refractory clad bell.

Advantages

No contact with oxygen from the atmosphere, minimised slag contact.
High alloy recovery due to the additions being made directly to the slag free surface of the liquid steel.
Low temperature losses.
Achievement of narrow composition tolerances.
Adjustment of the required casting temperature.
Exceptionally high degree of cleanness by separation of non-metallic inclusions.
Short treatment periods.
Low investment and running costs.
Possible plant modifications include:

Chemical heating.
Wire feeding
Facilities to add synthetic slag to achieve a high degree of desulphurisation.

* CAS = Composition Adjustment Sealing by Argon Bubbling (Under licence from Nippon Steel Corporation)

CAS-OB Unit*

The above is an extension of the CAS process and offers the possibility to heat ladles by the exothermic reaction between oxygen and aluminium.

Advantages

The same features as the CAS process.
Heating rates of up to 15°C/min.
Short treatment times.
Low investment and running costs.
Avoidance of re-cycling of ladles when delays at the continuous casting machine call for temperature adjustment.

* CAS-OB = Composition Adjustment Sealing by Argon Bubbling with Oxygen Blowing (Under licence from Nippon Steel Corporation)