2. The main refractory wear mechanism at the bottom
The damage to the bottom of the ladle, especially the impact area, may be the second reason why the ladle cannot be used and needs to be repaired or rebuilt. The typical feature is: the higher the height of the ladle, the worse the wear of the refractory in the bottom area. Other relevant factors may include tapping temperature and furnace height. There are three main stages:
1) Thermal spalling-temperature gradient and tapping caused the formation of vertical cobweb-like cracks on the bottom hot surface at the early stage of furnace age; 2) The penetration of molten steel and slag-molten steel and molten slag penetrate into the hot surface at the bottom, especially through vertical cracks formed on the surface; 3) Structural cracking-the subsequent thermal cycle causes the structural cracking in the alternate hot surface area, and then a new refractory surface is formed. Once the newly formed refractory surface is exposed to molten steel and slag, the second and third stages will be repeated.