Heat and thermomechanical treatment of powder structural steels (Review)

Heat and thermomechanical treatment of powder structural steels are reviewed and analyzed. It is shown that heat and thermomechanical treatment of powder steels have some peculiarities associated with presence of porosity in them. These peculiarities comprise the necessity of using protection media under heating for quenching lower thermal conductivity of powder steels as compared with rolled ones and therefore worse hardenability and a necessity of intensifying cooling process during quenching. Besides, presence of essential number of macro- and microdefects in powder steels results in shear of critical points under heating and cooling of steels. A peculiarity of thermomechanical treatment of powder steels as compared with rolled ones is the necessity of using higher shrinkage of porous sintered samples for their maximum condensation