Abstract

In the past decade, powder metallurgical (PM) stainless steel components have gained industrial traction due to their ability to create complex shapes with high dimensional precision, faster production rates, and processes involved with reduced environmental impact compared to traditional casting methods. The current study focuses on metallurgical investigation of austenitic (316L), ferritic (430L), and martensitic (410) stainless steels produced using powder metallurgy processes, consolidated through both microwave hybrid heating and conventional sintering methods. The densification response, microstructure evolution, mechanical properties and corrosion resistance of conventionally sintered samples are compared with those microwave hybrid heating techniques at super-solidus region temperature. The study also explores, how these properties are interrelated to microstructural morphologies including grain and pore morphology which is analyzed using image analysis techniques. The microwave hybrid sintering results in superior densification, finer microstructural characteristics and enhanced properties (mechanical & corrosion) over traditional sintering techniques. Specifically, microwave sintered 316L, 430L, and 410 steels have shown significant improvements in strength and ductility, with values of 457 +/- 16 (22.1%), 466 +/- 6 (17.2%), 476 +/- 26 (19.5%) in strength, and 25 +/- 1.3 (20.2%), 14 +/- 1.5 (21.4%), 11 +/- 1 (26.4%) in ductility, respectively than those of conventionally sintered ones. Additionally, the corrosion rate for microwave sintered 316L steels is 14 times lower, and for 430L steels, it is six times lower than that of their conventionally sintered counterparts. However, the corrosion rate for 410 steel shows only slight differences between the two sintering methods.