Using thermographic slag detection systems

The ever growing requirements on the cleanness of steel make slag-free tapping at the converter and slag-free pouring at the continuous necessary. Various systems have established themselves for early slag detection. Most of them work on the electromagnetic principle. Especially when used at converters which use darts or balls as closing devices, these systems show a relatively high amount of false interpretations. Moreover, the sensors of the electromagnetic systems are integrated in the converter vessel which makes it impossible to replace a demaged sensor during a converter campaign. During the last few years the service lives of refractory linings have been considerably extended. This has also increased the risk of failure of the sensor during a campaign. The thermographic slag detection system (TSD) is based on purely optical detection of the tapping stream at the converter and functions with any converter vessel or taphole design. The only prerequisite is a free view of the tapping stream towards the end of tapping. All components are easily accessible independent of the mode of operation and can be exchanged at any time. This guarantees a high availability of the system. Thyssen Krupp Stahl has been using thermographic slag detection systems from Amepa GmbH since June 1999. Therefore comprehensive experience and results have been obtained since the installation of the first system. The article presents the results obtained with four systems installed in the Dortmund, Beeckerwerth and Bruckhausen works.