The refractory castables for rolling steel heating furnace are simpler and easier to construct than masonry with refractory bricks, with low engineering cost and short construction period. Compared with bricks, it can save energy about 70%: the use cycle is 3~6 years, which is 14 times higher than using high alumina bricks. The castable material can be processed into various shapes of overall furnace lining, and the construction speed is fast, which is a better material for industrial furnace construction. With the application of ultra-micro powder technology in castables, clay-bonded castables are mostly replaced by low-cement-bonded castables. low-cement-bonded castables have the advantages of high strength, good volume stability and good construction performance. Therefore, low cement bonded castables are widely used in hot work kilns. However, in the process of choosing castables for furnace lining, the designers of hot work kilns at home and abroad mostly think that the products with high alumina content in castables are better than those with low alumina content in all aspects.