Process for making sintered composite mechanical parts

In a process for making a sintered mechanical part with a complex profile by preparing separately an inner compact having a shaft and an outer compact having an opening by the compression of iron-based metal powders, and sintering both compacts in a state where the inner compact is fitted into the outer compact,

• the improvement which comprises:
• pressfitting the shaft of the inner compact into the opening of the outer compact with an interference fit to form said mechanical part without exceeding the rupture strength of said outer compact, and wherein the percent of interference in relation to the inner diameter of the opening of the outer compact is not higher than the value (0.23T+1 D+1.38)/300 wherein D is the inner diameter of the opening in the outer compact in millimeters and T is the wall thickness of the outer compact in millimeters, and subsequently sintering said mechanical part.