Increasing demands for sustainable manufacturing are accelerating the need for efficient scrap reutilization routes that extend beyond conventional remelting practices. In this context, solid-state reuse of machining chips presents a viable pathway for producing high-value functional materials while supporting circular economy objectives aligned with UN SDG-12. This work reports a novel processing strategy for fabricating stainless steel 316 metallic foams directly from turning chips using microwave sintering. Consolidation was carried out at 1050 °C and 1200 °C under an argon atmosphere to suppress oxidation and contamination while enabling rapid and energy-efficient sintering. Three foam architectures: chip-based, hybrid and space-holder foams, were successfully produced and systematically characterized with respect to macrostructure, microstructure and compressive response. Foams sintered at 1200 °C exhibited a well-defined and stable stress plateau with enhanced energy absorption capacity. Their lower plateau stress facilitated progressive deformation under compressive loading, indicative of improved impact resistance. The results demonstrate that chip-derived stainless steel foams produced via microwave sintering offer strong potential for energy-absorbing and crash-relevant structural applications, while providing a sustainable route for high-value metal scrap reutilization.
Shinde et al. (Mon,) studied this question.