A Study of Crack Initiation of Refractories by Cold Model Test

Abstract

A cold model test was made to simulate a crack behavior of cylindrical refractory structure. In the test, high-alumina (Al₂0₃ 90%) rectangular prism bricks were used. Strain was induced by mechanical loading. Srain state was simulated to that of bricks in a cylindrical furnace in which thermal expansion of refractories are constrained by shell.
Y-directional strain state which was given to the bricks partially and varied linearly (maximum value;ε_>yo)corresponded to circumferential strain state of bricks of the furnace, and y-directional partial loading resulted in the tensile strain in x-direction (maximum value; ε_xm) which corresponded to radial strainof bricks of the furnace.
Also, three point bending test of square section bar and compressive test of cylinder were carried outto get tensile critical strain (ε_b^t) and compressive one (ε_b^c).
Results are summarized as follows:
1. Cracks may be caused by ε_yo and ε_xm.
2. Critical strain to cause cracks in cold model test, has good correlation with E ε_b^t or ε_b^c