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℃,large TiN particles had little effect on hot ductility.In the temperature range from 975 to 925℃,reduction of area(R.A)declined rapidly from 81.88% to 63.16% with the size of particles decreasing from 40 to 20nm and quantity increasing from 1.4 to 11.9μm-2,respectively.In the temperature range from 875 to 825℃,R.Areduced 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 ℃.Intergranular fracture was easy to occur with higher critical stress below 825℃. Hot ductility of Ti-V bearing steel was studied by theoretical calculation and thermal simulation experiment. Meng, 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 ° C, large TiN particles had little effect on the thermal ductility. In the temperature range from 975 to 925 ° C, reduction (RA) declined rapidly from 81.88% to 63.16% with the size of particles decreasing from 40 to 20 nm and the amount increasing from 1.4 to 11.9 μm-2, respectively.In the temperature range from 875 to 825 ° C., R.Areduced 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 ° C. Intergranular fracture was easy to occur with higher critical stress below 825 ° C.