Introduction
In service, refractory linings are exposed to considerable thermo-mechanical loads. These loads are caused by externally thermal expansion or by temperature gradients in the refractory itself. Loads due to thermal expansion cause primarily material failure under compressive or shear loads, while temperature gradients in the refractory lead to tensile failure. Crucial factors are the lining design, e.g. the lining thickness, expansion allowance and the possible application of an insulation. Additionally, the creep and fracture behaviour influences the mechanical behaviour. To find an optimum for the lining design under certain operating conditions regarding material, lining thickness, expansion target, brick shape or the optional implementation of an insulation is a beneficial but complex task.
Strongly simplified calculation methods are still mainly applied for the design of refractory linings regarding the thermo-mechanic loads. However, Finite Element (FE) simulations are state-of-the-art of the thermo-mechanic behavior to investigate damage mechanisms. Therefore, it is logical to use FE simulations for the design of refractory linings.
Objectives and Motivation
- Development of a procedure for an optimum lining design from thermo-mechanic point of view
- Application of the procedure considering specifically chosen linings from steel industry applications based on certain criteria such as minimized thermo-mechanic loads
- Weighting of characteristic criteria, which induce thermo-mechanic loads or damaging mechanisms in refractories
The research activities within this project mainly consists of FE simulations and experimental investigations. Accompanying literature study about common lining designs should lead to a categorization and grouping of linings according to characteristic features (e.g. linings with and without insulation). The FE simulations should simulate the lining behavior for different cases (i.e. brick shapes, preheating conditions etc.). It is necessary to apply material models, which consider elastic behavior, mode I+II fracture or creep.
The experimental part of the planned methodology is focused on the necessity of material parameters. Mechanical tests including wedge splitting test, modified shear test, compressive and tensile creep tests are planned. Furthermore, the Young’s modulus will be determined. All the material parameters are required for the overall range of operating temperatures. The simulation results will be compared with results from stress and strain measurements conducted from linings in operation.The research activities within this project mainly consists of FE simulations and experimental investigations. Accompanying literature study about common lining designs should lead to a categorization and grouping of linings according to characteristic features (e.g. linings with and without insulation). The FE simulations should simulate the lining behavior for different cases (i.e. brick shapes, preheating conditions etc.). It is necessary to apply material models, which consider elastic behavior, mode I+II fracture or creep.
The experimental part of the planned methodology is focused on the necessity of material parameters. Mechanical tests including wedge splitting test, modified shear test, compressive and tensile creep tests are planned. Furthermore, the Young’s modulus will be determined. All the material parameters are required for the overall range of operating temperatures. The simulation results will be compared with results from stress and strain measurements conducted from linings in operation.
Results and application
The procedure for lining design is expected for common use cases to replace empirical rules. During the executed activities, further results should be generated such as material parameters from the mechanical tests as well as damaging mechanisms for different FE simulation cases. Furthermore, information is expected regarding a correlation of results from FE simulation and laboratory experiments from the lining testing furnace. Finally, concepts for optimized refractory linings in terms of thermo-mechanic point of view, should be available.