Mechanische Charakterisierung kohlenstoffhaltiger feuerfester Baustoffe bei hohen Temperaturen

Research output: ThesisDoctoral Thesis

Organisational units

Abstract

Magnesia-Carbon (MgO-C) bricks are used as refractory lining, for example in LD converters, steel ladles and electric arc furnaces. Temperatures up to 1700�C may be reached during service. In order to obtain information about the behavior of the refractory materials in the high temperature range, laboratory conditions must be created in order to reproduce operating conditions regarding temperature and atmosphere. It is essential that the mechanical testing of carbon containing refractory materials at high temperatures requires measures to protect the carbon against oxidation. The aim of the work is the further develop of experimental setups to perform high temperature tests under reducing conditions. Test setups were designed for tensile and compressive creep tests in which the sample is embedded in coke breeze during the test. This embedding reduces the oxygen partial pressure in the vicinity of the sample during the creep test. In order to characterize the Mode-I behavior, a high temperature testing device for noncontacting displacement measurement using a laser speckle extensometer was designed based on the wedge splitting test method according to E. Tschegg. This allows fracture mechanical tests at temperatures up to 1500�C in argon atmosphere. Resin and pitch bonded MgO-C materials were tested in an application relevant temperature and loading range. The Norton�Bailey creep parameters were identified using a Matlab program developed at the chair of ceramics. In addition, fracture mechanical parameters such as the specific fracture energy and the notch tensile strength were calculated based on the data obtained from tests. An inverse simulation process based on the finite element method enables the tensile strength, the total specific fracture energy and the softening behavior at high temperatures to be determined. The material parameters received can be used in finite element simulations for refractory linings under operating conditions.

Details

Translated title of the contributionMechanical characterisation of carbon containing refractories at high temperature
Original languageGerman
QualificationDr.mont.
Awarding Institution
Supervisors/Advisors
Publication statusPublished - 2021