DYNAMIC PROPERTIES OF PHOSPHORUS-ALLOYED SINTERED STEEL.

A phosphorus-alloyed PM steel (0. 8P; 0. 3C) with ferritic-pearlitic microstructure was studied at four different densities ranging from 6. 6 g/cm**3 to full density. Due to sintering in the two-phase ( alpha plus gamma ) region, two levels of phosphorus concentrations were present, corresponding to ferrite with two different hardness levels. The yield and ultimate tensile strengths increase approximately linearly with the density. The elongation to fracture is almost unnaffected by changes in density. The impact energy is affected by the type of fracture. The fracture toughness increases with the density as long as the fracture mainly has a ductile character. The crack propagation resistance generally increases with density. The low cycle fatigue properties are unaffected by density in porous materials, whereas the corresponding data for fully dense steel are superior.