Study of the behaviour of cement and mass joints utilised in aggregates of the steel industry

This work is dedicated to the study of the behaviour of the refractory joints encountered in the lining of metallurgical vessels. ln many situations, especially in big vessels, the joints are expected to fulfil more functions than the simple 'joining' role: - to relax the thermo-mechanical stresses; - to ensure a satisfactory heat evacuation through the lining, during all the vessel life. ln this work, special attention has been paid to the blast furnace hearth. ln the lining of this equipment, broad joints (thickness range: 40-80 mm) and thin joints (range: 0.55 mm) are needed in order to ensure the two mentioned functions for many years. Two other, more special, cases have also been considered in this study: - the lining of the flat parts of the wall of steel ladles, which have been modified in order to increase their capacity; - the lining of sensitive parts of a vacuum vessel for the treatment of liquid steel: the thermo-mechanical behaviour of the lining in the bottom of the vessel and the snorkels is sensitive to the design of the joints. The different aspects of the subject covered in this work are: - the study of the joining materials at laboratory scale; - the modelling of the joint properties and of their behaviour as a component of the entire aggregates; - the industrial experience.