关键词: 热风炉, 混风室, 刚玉质浇注料, 抗热震性, 热膨胀性能

Abstract: In response to the problem of abnormally high temperatures at multiple points in the outlet pipeline of the mixing chamber of a hot blast stove in a certain iron plant,samples were selected from the residual lining after dismantling the mixing chamber.The chemical composition,microstructure,phase composition,thermal expansion and thermal shock resistance of the lining material were analyzed.The results show that the lining material adopts corundum castables,which have high strength and good wear resistance,and can effectively resist hot air erosion and CO corrosion damage.However,it has poor thermal shock resistance,and exhibits significant thermal expansion at high temperatures,leading to large internal thermal stresses.These stresses cause cracks to form within the material,which in turn allow the high-temperature and high-pressure hot blast to leak,resulting in an increase in the steel shell temperature.The measures taken are as follows:changing the corundum castables to corundum-mullite castables;when the mixing chamber is constructed with layered casting,the upper layer of castables must be cast before the initial setting of the lower layer of castables to ensure better fusion between the two layers of castables;and the three-way junction part can be changed from combined bricks to integral corundum-mullite castables.After the improvement,the surface temperature of the tube shell has dropped to normal and remains stable,the repair effect is good,and the service life is extended by about 5 years.

Key words: hot blast stoves, mixing chambers, corundum castables, thermal shock resistance, thermal expansion performance