Our alumina crucibles are designed to both maximize density and improve thermal shock. They are ideal for melting steel; cobalt based alloys, nickel, chromium and manganese alloys, as well as iron.
Our high temperature alumina crucibles are manufactured in sizes up to 4000# and can be constructed to your specific needs both in size and in material selection to maximize chemical attack. Our alumina induction crucibles offer increased resistance to saturation, erosion and thermal shock allowing less slag build up and longer life.
The grain distribution and refractory selection are important to minimize wetting and penetration of the crucible. Saturation not only leads to erosion but can eventually cause different thermal expansions between the crucible wall and the saturated area, causing cracking and failure. Low melt baths are commonly a major source of thermal failure with the steep thermal gradient above and below the melt line.
Extending the holding time prior to tapping, especially with excessive slag coagulants or fluxes, commonly presents itself at the melt and slag line causing severe erosion or ringing at this interface. While it is always recommended to tap as quickly as the desired temperature is achieved, it’s recognized this may not always be possible due to chemistry verification.
Excessive build up on the walls, especially if it is consistent, is commonly caused by a particular alloy causing a reduction in the refractory, unlike the ringing at the melt and slag line interface. This build up will cause premature failure of the crucible.
Proper installation of the backup refractory will increase density and provide more crucible service. The installation procedure should follow that of a ram lining with care to blend the transition from the back up to the top cap material. Properly installed back up will keep the crucible in compression and venting of the top cap will help to minimize separation between the top cap and the backup.
Contact us with your requirements and see what we have to offer both in product and experience.