AvestaPolarit has upgraded the gas control system on its Argon Oxygen Decarburisation (AOD) converter at its steel mill on Shepcote Lane in Sheffield. This will provide greater operational flexibility through increased gas flows and enhanced control capability during the refining of stainless steel. Production at the Shepcote Lane site consists of stainless sheet between 0.4 and 6mm in thickness and up to 1.5m wide. The AOD converter is used to remove carbon to the extremely low levels required for stainless steels with the liquid steel being supplied from the electric arc furnace (EAF) at the plant. The gas system was supplied by VAI Industries (UK) to give increased gas flows and better control. The four main gases are oxygen, pure and industrial argon and nitrogen. AvestaPolarit stipulated that all control valves were to be pneumatically actuated, controlled with electro-pneumatic positioners with closed position indication. The block and vent valves were also pneumatically operated fitted with open and closed position indication switch boxes. Flowserve Flow Control, already an approved supplier to AvestaPolarit, was chosen to provide valves for the system.
Nine Worcester V-Flow control valves were stipulated (including four in stainless steel and four in Monel) to deal with the demanding application and one in carbon steel, in sizes ranging from 14mm to 80mm. Additionally,Worcester Controls’ manual isolation valves, ranging up to 150mm including three Series 52 valves in Monel were incorporated into the
system. All pneumatically operated valves were fitted with Norbro actuators and
PMV/Norbro ancillaries.
