Analysis of the causes of accidents in the position of the water inlet block of the ladle

The function of the ladle nozzle block is to protect the vent core. If it is abnormally cracked during use, it will not only fail to protect it, but accidents may occur under severe conditions. The main reason for the cracks in the ladle nozzle block is that in addition to the unqualified quality of the block itself, various factors in the use environment of the steelmaking manufacturer will also affect the stability of the ladle nozzle block.

The unreasonable design of the nozzle block for the ladle is mainly reflected in the physical and chemical indicators. The unreasonable material ratio makes the thermal shock resistance too low, cracks and breaks during use, resulting in breakout. To solve one of the problems, it is necessary to adjust the material ratio of the nozzle block for the ladle to improve the thermal shock performance; in addition, the appropriate increase of steel fiber can improve the strength of the block to a certain extent and enhance the stability.

Figure 1 Ladle nozzle block

Throughout the major domestic steel manufacturers, when installing breathable bricks, most of the bricks are installed directly on the steel shell, and a few will put a layer of material on the steel shell. Ke Chuangxin Material recommends the latter operation. This is because the steel The shell may be deformed and uneven due to factors such as high temperature, lifting impact, unpacking impact and other factors after long-term use. After the air-permeable brick is installed, the bottom of the ladle nozzle block and the steel shell point at the bottom of the ladle cannot be closely contacted. , There will be more or less gaps, which may lead to cracks at the bottom of the breathable brick base, and leakage of steel. From a mechanical point of view, the uneven bottom of the seat brick is equivalent to adding a fulcrum to it. Under the action of the hydrostatic pressure and thermal shock of the steel, the seat brick is prone to cracks. Therefore, when placing the air-permeable brick block, we recommend smoothing out the steel shell with chromium corundum castable and replacing the heavily deformed backing plate in time.

In order to facilitate the installation and removal of the ladle nozzle base bricks, steelmaking manufacturers generally reserve a gap of 40-100mm between the base bricks and the bottom bricks of the ladle, and finally fill it with castables. We recommend that the castable should be corundum with high quality and superior material, which has the advantages of good fluidity and corrosion resistance. The quality of the joint filler is poor, and it will be consumed too quickly after being corroded by molten steel, resulting in the exposure and cracking of the breathable brick base, which affects the use of the breathable brick.

Figure 2 Steel shell bottom plate

Nowadays, with the rapid development of steel smelting technology, the out-of-furnace refining process has become an important part of the steel smelting process, and the correct use of breathable bricks is closely related to the safety of production.