FORGING AND SINTERED CHARACTERISTICS OF DUPLEX STAINLESS STEELS PREPARED FROM 316L AND 430L POWDERS

Four different duplex stainless steel samples were prepared from 316L and 430L pre-alloyed powders with and without Cr, Ni, Mo and Cu elemental addition. The green compacts were prepared using the universal testing machine under 560MPa pressure and then sintered at 1350°C for 4 hrs in dry nitrogen atmosphere. After sintering the sintered preforms were subjected to density, metallographical and mechanical properties evaluation. Sintered preforms exhibited density of 81.583% theoretical density. Microstructure of sintered DSS revealed the lamellar constituents with austenite. To increase the density of the duplex stainless steels, forging operation was carried out at 1050 ± 10oC. After forging the samples were kept in a muffle furnace for 30 minutes then subjected to subsequent water quenching. Forged duplex stainless steels exhibited density in the range of 94-96% theoretical density. Microstructure of the forged DSS exhibited the austenite with fine grains of ferrite. These forged DSS exhibited enhanced tensile strength in the range of 715 to 816 MPa and ductility in the range of 6-8.4%. These forged duplex stainless steels were found to be incorporated with added ferrite content.