Abstract The work is devoted to the study of microstructure and metallurgical parameters on the level of hot ductility in the critical temperature range. Under this condition the steel microstructure consists of the ferrite and austenite mixture and the deformation is realised at the austenite grain boundaries. The characteristics of localised deformation in intergranular ferrite layers are discussed partly from view point of ferrite morphology, partly from view point of ferrite volume fraction. Simultaneously, the action of the residual elements (Cu, Sn, Sb) is analysed and their influence on the modification of attained level of hot ductility is discussed. The conditions leading in steel to the surface enrichment of these elements and the evaluation of its consequences on the development of hot ductility shortness are included in the presented solution. The beneficial effect of the Ni-addition and proposed mechanism of its action are analysed.