Effect of microadditions of aluminum and vanadium on the susceptibility to quench cracking in powder steels

The possibility of reducing the susceptibility of hot-deformed powder steels to quench cracking due to microalloying with aluminum and vanadium has been studied. Samples of eutectoid steels were obtained on the basis of chromium-molybdenum iron powder, as well as on the basis of unalloyed iron powders with various impurity contents. Aluminum and vanadium were doped as ferroaluminum and ferrovanadium correspondingly. The technological process of obtaining prismatic samples included the sequential execution of operations of mixing the components of the charge, cold pressing charge, sintering porous blanks and hot forging. As-forged samples were carburized and quenched in an aqueous solution of NaCl. To determine the susceptibility of powder steels to quench cracking, the quench cracking index was determined. It has been found that doping microadditives of Al and V is favourable to reduce the susceptibility of powder steels to quench cracking. The effect of aluminum is associated with the activation of the processes of formation of common grains near interparticle boundaries as well as the processes of cohesive interaction. The presence of vanadium ensures the formation of dispersed precipitates of vanadium carbides and carbonitrides, which contribute to the implementation of the effect of dispersion hardening of interparticle boundaries.