Thermal Stress Analysis of BOF Accounting for Friction Force Experimentally Measured

Abstract

Thermal stress simulations by the finite element method (FEM) are widely used to analyze refractory damage caused by mechanical factors. Issues studied by FEM simulation of refractories include joint conditions, and friction between refractories. The static friction coefficient and dynamic friction coefficient between MgO–C refractories with various surface conditions were measured. And the effects of joint conditions and friction force on the thermal stress analysis of the refractory lining in the barrel and cone of the converter were investigated numerically. The results are summarized as follows.
(1) The friction coefficient between refractories that had various surface conditions was measured. As a result, a static friction coefficient of 0.52 and a dynamic friction coefficient of 0.42 were obtained for the friction working between the surfaces of baked MgO–C refractories.
(2) It is necessary to consider friction force in the thermal stress analysis because local abnormal increases in stress occur, corresponding to large displacement of the bricks. Considering the situation of wear brick in operation, it was appropriate to apply for the value of baked brick as a friction coefficient.
(3) The effect of the joint conditions used here, which were contact element, gap element, and anisotropy of mechanical property, on the results of calculations of thermal stress by FEM was comparatively smaller than that of friction force when friction force was considered. If the logic of displacement and stress transmission on two bricks is considered, contact element is appropriate from the viewpoint of stress transmission.