At the beginning of August, the Turkish steel producer Çolakoglu Metalurji AS gave Siemens VAI Metals Technologies the final acceptance certificate for the modernization of electric arc furnace no 1 in the Gebze Plant just 4 days after the first heat.

Being already one of the most productive electric arc furnaces in the world before modernization, its performance has been significantly improved once again.

Electrical active power input has been increased by eight percent, while the electrical energy consumption has been reduced by six percent at the same time, without increasing the fossil energy consumption. This has boosted the overall productivity of the electric arc furnace by 12% without any change in the tapping weight.

Çolakoglu produces its steel in a Siemens VAI Simetal Ultimate electric arc furnace operating since January 2007. The furnace was originally designed for a charge volume of 250 tonnes with a two bucket charge operation. In the mean time the furnace was operated with a tapping weight of 315 tonnes which led to an increased cycle time with more than 2 scrap buckets charge due to higher tap weight and scrap availability with lower density.

The modernization project involved renewing a large part of the mechanical equipment of the electric arc furnace. This included the lower and upper shells, gantry, lifting columns and furnace cover. These measures increased the volume of the shell by around 20% but kept the tapping weight constant. The furnace can now again be charged with just 2 buckets and produces over 2.5 million tonnes of steel per year. New current conducting electrode arms for electrodes of up to 800 millimeters in diameter have also been installed. This modernization allowed increasing the electrical active power input by 8% while reducing electrical energy consumption by 6%.