Effects of sintering parameters on the mechanical properties of a Fe-2Cu-2Ni-0.9Mo-0.8C steel

Iron alloyed with nickel, copper, molybdenum and carbon was examined to determine the role of several processing parameters on the final sintered properties for densities in the range of 7.2 to 7.4 g/cm³. The study included the effect of compacting pres sure, sintering temperature and time, and lubricant amount, on the mechanical properties and dimensional variation. In addition, heat treatment was investigated. A systematic method was used to determine critical parameters and their interactions, while tailoring the microstructure. Thereafter, those parameters were tightly controlled whereas tolerable variations for other parameters were examined to reduce costs, without sacrificing final sintered properties. The study demonstrates possible property and dimensional optimisation for this steel. This procedure achieved an as-sintered strength of 940 MPa and a toughness of 29 J/cm², using a conventional single press, single sinter technology. Heat treatment resulted in a tensile strength over 1.2 Gpa while the toughness remained constant.