Effect of Compaction Pressure Applied to TiC Reactants on the Microstructure and Properties of Composite Zones Produced In Situ in Steel Castings

Compacts for the synthesis of composite zones in castings were obtained by cold pressing powders of the TiC reactants under a pressure of 250, 300, 500 and 600 MPa. The all compacts made under different pressures were placed in a mould cavity and poured with liquid unalloyed low-carbon steel. From the resulting casting, four composite zone A, B, C, D, produced in this casting by in situ method. In all composite zones, TiC and ferrite (alpha Fe) were obtained. Additionally, in zones A, B and C the presence of graphite (C-gr) was also stated. The surface fraction (S-f) of C-gr decreases in composite zones A divided by D, while both the Sf of TiC and hardness VH30 increase in these zones with increasing compaction pressure of the reactants. Too low compaction pressure applied to the TiC reactants suppress the effective propagation of the reaction of synthesis.