Reaction-bonded silicon carbide square beams are suitable for the load-bearing structural frames of tunnel kilns, shuttle kilns, double-layer roller hearth kilns, and other industrial kilns. This product offers high load-bearing capacity at elevated temperatures, does not bend or deform during long-term use, and has a service life several times longer than that of other materials, making it an ideal kiln furniture for industries such as sanitary ceramics and electrical porcelain. The product exhibits excellent high-temperature flexural strength, thermal shock resistance, and oxidation resistance. It remains deformation-free over prolonged use, significantly reduces energy consumption, and does not increase the weight of kiln cars.