Meaning
Ratio of the mass of a powder metallurgy part to its volume after the high temperature bonding process determines the strength and elastic modulus of the material.
Performance Correlation
Mechanical properties such as tensile strength and fatigue endurance improve as the sintered steel density approaches the solid state value. Porosity acts as a series of internal stress risers that reduce the effective cross sectional area available to carry loads. For every one percent increase in density there is a disproportionate gain in the impact energy and elongation of the material.
Density Achievement
Process parameters including the compaction pressure and the use of lubricants influence the initial green density which then dictates the final sintered steel density. Double pressing and double sintering techniques allow manufacturers to reach values above 7.4 grams per cubic centimeter for demanding applications. High temperature sintering above 1250 degrees Celsius also promotes greater shrinkage and better pore closure.
Commercial Measurement
Producers use the Archimedes method to measure the sintered steel density by weighing the part in both air and water. This non destructive test provides an accurate average value for the entire component. Maintaining a consistent sintered steel density across different production lots is required for ensuring that the parts meet the performance specifications required by the automotive and aerospace industries.
