PM²TEC 2004, in Chicago, USA. Authors: Prasan K. Samal, Owe Mårs, Ingrid Hauer. P/M ferritic stainless steels 409L and 434L are most commonly specified for automotive exhaust system components. A sintered density of 7.25 –7.30 g/cm³ is desired in these applications, in order to meet mechanical property, as well as, leak tightness, thermal fatigue, oxidation resistance and weldabilty criteria. With each of these two alloys, the desired sintered density of 7.25- 7.30 g/cm³ is achievable via various combinations of compaction and sintering parameters. This paper compares the room and elevated temperature mechanical properties, as well as the microstructure, of P/M 409L and 434L sintered to 7.25 – 7.30 g/cm³ using various combinations of process parameters. Sintering temperatures employed range from 1232°C (2250 °F) to 1366 °C (2490 °F).