Hot Ductility of Ti-V Bearing Microalloyed Steel in Continuous Casting

Hot ductility of Ti-V bearing steel was studied by theoretical calculation and thermal simulation experiment. Meanwhile, microsegregation and precipitates were analyzed. The results showed that elements S, Ti and O were enriched at the grain boundaries, while the hot ductility was deteriorated by inclusions of (Fe,Mn,Si, Al) (S,O) in the interdendritic region. At the temperature of 1 100 degrees C, large TiN particles had little effect on hot ductility. In the temperature range from 975 to 925 degrees C, reduction of area (R. A) declined rapidly from 81.88% to 63.16% with the size of particles decreasing from 40 to 20 nm and quantity increasing from 1.4 to 11.9 mu m(-2), respectively. In the temperature range from 875 to 825 degrees C, R. A reduced unobviously from 35.14% to 28.6% with ferric films thickening gradually. The critical stress, 88.79 MPa, was equal to tensile strength at 825 degrees C. Intergranular fracture was easy to occur with higher critical stress below 825 degrees C.