Abstract: Aiming at cast-rolling forming technology, by means of metallographic observation, mechanical properties test and fracture observation, the effect of different casting methods (sand casting and centrifugal casting) on the microstructure and the mechanical properties of the Q235B carbon steel are investigated. The results show that the microstructure of Q235B carbon steel at room temperature is mainly composed of ferrite and pearlite. The ferrite in the sand casting blank exists in the form of massive, and the grains are coarse. The ferrite in the centrifugal casting blank exists in the form of needle and massive, and the grains are small. The tensile strength, plasticity and impact toughness of the centrifugal mold casting blank are significantly better than that of sand casting blank. The tensile fracture of sand casting blank is a mixed fracture characteristics of quasi-cleavage and dimple. The impact fracture is almost completely brittle cleavage fracture characteristics. Centrifugal casting tensile fracture is almost entirely ductile fracture characteristics, and the impact fracture is composed mainly of tearing dimple and cleavage region.

Key words: ring casting blank;casting technique;casting-rolling forming;microstructure;mechanical property