FATIGUE CRACK PROPAGATION RESISTANCE OF SINTERED OBTAINED FROM PREMIXES OF 316 AND 434 POWDERS AND FROM A PREALLOYED DUPLEX POWDER

摘要

Duplex stainless steels are widely used in chemical, petrochemical, nuclear and food industries: this is due to their combination of good mechanical properties and high corrosion resistance in many different environments. Because of their low Ni content, their cost is absolutely competitive if compared to austenitic stainless steels with an analogous corrosion resistance. However, duplex stainless steels are characterized by considerable difficulties from the manufacturing point of view, and powder metallurgy offers an excellent alternative to produce these steels. Attempts have been made to introduce ferrite phase in austenitic stainless steels either through the introduction of silicon powder, or directly using premixed or prealloyed stainless steels powders.