Why do high alumina sleeve bricks crack after being baked in the oven?
High alumina sleeve bricks are not used much for repairing hot air outlets. They are hollow tube bricks with male and female interfaces at both ends. They include sintered high alumina, unfired aluminum carbon, etc.
High alumina sleeve bricks are bricks used for passages through which molten steel flows. During use, they react with alkali metal oxides, resulting in corrosive slag sticking. Because it is a consumable product, high-aluminum sintered sleeve bricks are often used because the cost of high-aluminum bricks is relatively low.
The reasons for cracks in high alumina sleeve bricks after baking are firstly the material's own factors, and secondly the expansion factor of thermal stress. Because the tubular sleeve bricks have thin walls and high columns, they are artificially formed by static pressure or molding. After demoulding, external pressure on the thin walls of the bricks during stacking and loading in the kiln causes surface cracks.
Second, the temperature during the production of sleeve bricks is between 1300 and 1500°C. The secondary mulliteization will expand by 5-10%, causing the sleeve bricks to shrink and form micro-cracks on the surface. Such cracks are difficult to avoid. Due to thermal stress, the sleeve bricks can tightly tack together after docking.
High alumina Sleeve bricks are baked at low temperatures in the oven and cannot be baked at high temperatures. The sintered high-alumina sleeve bricks are fired at high temperatures. When baking in the oven, attention should be paid to and the temperature rise curve should be controlled, and it should not rise sharply or significantly. In order to avoid damage and cracks caused by thermal load during baking of high-aluminum sintered sleeve bricks.
There are many reasons for cracks in sleeve brick barbecues. From the actual use point of view, cracks will also occur when the stress impact exceeds the limit of the brick itself.
To prevent cracks from occurring, just bake at low temperature or do some simple baking. If cracks are found, you can also use similar materials to simply apply them on the cracks of the High alumina sleeve bricks. Select them when shipping. If If you find too many micro-cracked sleeve bricks, remember not to pack them into boxes to avoid affecting their service life during use.
