The properties of sintered high-alloy nickel-copper steel N32D4 (32% Ni-4% Cu)

Summary

• 1. A study of the properties of a sintered high-alloy nickel-copper steel made by two techniques demonstrated that higher pressure of the first compacting and temperature of the first sintering (variant 1, Table 1) produce little increase in the density of finished specimens, and have an insignificant effect on strength characteristics in static tests. In dynamic tests (impact strength, fatigue limit), there is a marked decrease in the strength of specimens made by variant 2; this is due to the higher sensitivity of dynamic strength characteristics to porosity and compositional microheterogeneity, which are greater in specimens whose first sintering was performed at a low temperature.

• 2. The short and long-time and fatigue strengths of the sintered steel at elevated temperature are very low, which restricts the scope of its utilization as a heat-resisting constructional material.

• 3. A study of similar sintered nickel-copper steels made from alloy powders produced by the simultaneous reduction of iron, nickel, and copper oxides showed that fuller homogenization of the sintered steel improves its ductility and dynamic strength characteristics, while slightly reducing its static strength.