Experimental and numerical simulation of a stainless steel coating subjected to thermal fatigue

Continuous casting rollers are subjected to thermal cyclic loading termed thermal fatigue. This study presents a 3-D, experimental and numerical, simulation of the thermal loads and of the associated stresses. The results are validated by thermal loading a cylinder with dimensions of one fifth of the real cylinder. Coatings of different chemical composition and thickness are deposited on the cylinder’s outer surface for protection. Temperature distributions are measured to determine the thermal history of the cylinder from the initial state up to the stabilization of the cycle. The temperature range is established to correspond to typical industrial values. A numerical simulation is carried out to evaluate strain and stress levels induced by thermal loading using the finite element method. In order to numerically estimate thermal loading with the highest accuracy, an inverse method is used. The parameters of thermal laws are identified by minimizing the difference between the measured data and the numerical forecast of the model. After this optimization process, the mechanical system is modeled applying the optimized thermal loading. The laws of elastoviscoplastic behavior are applied with their constitutive parameters adapted to the working temperature range of the cylinder. This modeling constitutes a technological means of selecting the nature of the coating material and its optimal thickness by testing different thermal loadings in order to optimize the industrial process.