The mechanical force borne by the lintel and “brackets” in the inclined channel area of CDQ and the thermal stress generated by the top-down temperature gradient were simulated by ANSYS software. The following conclusions are drawn. (1) The mechanical force has very mild effect on the damage of the “brackets”. (2) The temperature gradient caused by the uneven temperature distribution of CDQ oven is the key factor affecting the “bracket” damage. The different expansion of refractory materials in various parts results in the thermal stress concentration which tears the “brackets”. (3) The structure adjustment of the “brackets” has very little effect on the thermal stress distribution. (4) The multi-phase nitride bonded silicon carbide for CDQ can effectively alleviate the stress concentration at the “brackets”, realizing the long-life and stable operation.