Authors:
Dr. Erwan Brochen | Forschungsgemeinschaft Feuerfest e. V. at the European Centre for Refractories | Germany
Michael Kaminski | Forschungsgemeinschaft Feuerfest e. V. at the European Centre for Refractories | Germany
Dr. Christian Dannert | Forschungsgemeinschaft Feuerfest e. V. at the European Centre for Refractories | Germany
Laura Erbar | Koblenz University of Applied Sciences | Germany
Katharina Sarnow | Koblenz University of Applied Sciences | Germany
Prof. Dr. rer. nat. Olaf Krause | Koblenz University of Applied Sciences | Germany
Dr. habil. Jacek Podwórny | Łukasiewicz - Institute of Ceramics and Building Materials | Poland
Dr. Karolina Dudek | Łukasiewicz - Institute of Ceramics and Building Materials | Poland
Dr. Magdalena Kujawa | Łukasiewicz - Institute of Ceramics and Building Materials | Poland
Dr. Robert Kusiorowski | Łukasiewicz - Institute of Ceramics and Building Materials | Poland
Whenever a refractory product is used in a lining of industrial vessels at high temperatures, it simultaneously experiences a thermal gradient and mechanical loading. In operation, each part of the lining expands, as do all the neighbouring parts, resulting in huge compressive stresses parallel and near to the hot face of the linings. As a result, specific microstructural changes that condition the behaviour of the material in use take place. These changes could, until now, not be reproduced in laboratory. The closest commonly used method to experimentally simulate the impact of temperature and load is the determination of refractoriness under load and it only applies stresses of 0,2 MPa in a single direction.
With a new testing device, developed at FGF, refractory materials can be restrained or subjected to loads at the hot face of a prismatic test piece (Format B), which is heated up to 1700°C though one of its end faces and accordingly experiencing a thermal gradient. Stress levels of up to 30MPa were assessed or applied in two perpendicular directions near to the hot face to trigger unique microstructural changes. Besides microstructural characterisation, the part of the test pieces that experienced high temperatures und bidirectional compression can be investigated after testing (e.g. BD, CCS or TSR measurements) and the results compared to those from parts of the test pieces that experienced much lower temperature and no compressive stresses.
The behaviour of refractory materials used as linings can be understood better, which opens new perspectives for material development.