Green manufacturing impact on fatigue strength: A comparative analysis of heat-treated AISI 420 and plastically deformed AISI 301LN stainless steels

The demand for sustainable and high-performance materials has driven advancements in stainless steel production, including the development of "green stainless steels" that reduce environmental impact without compromising mechanical properties. Traditional steelmaking emits approximately 1.8 tons of CO 2 per ton of steel, whereas the green manufacturing process used in this study replaces coke with sustainably sourced charcoal, significantly lowering emissions while capturing CO 2 . This study investigates the fatigue behavior of two green high-strength martensitic stainless steels (HSMSS), AISI 420 and AISI 301LN, which differ in composition, microstructure, and processing. AISI 420 underwent quenching and tempering (QT) to achieve a predominantly martensitic structure, while AISI 301LN, a TRIP steel, was cold-rolled with 54% thickness reduction, inducing partial martensitic transformation. Despite their similar ultimate tensile strength (σUTS ∼1530 MPa), hardness (∼46 HRC), and surface roughness, their fatigue resistance differed significantly. Through X-ray diffraction (XRD), optical microscopy (OM), scanning electron microscopy (SEM), and Electron Backscatter Diffraction (EBSD), this study explores how distinct processing routes influence microstructural evolution and fatigue performance. The results provide insights into how sustainable manufacturing methods contribute to fatigue resistance while addressing environmental concerns. • Both materials were produced via a green manufacturing process certified by ResponsibleSteel™, showcasing the feasibility of combining high-performance materials with environmentally responsible practices. • AISI 301LN, after cold rolling, demonstrated significantly higher fatigue strength across all tested cycles compared to AISI 420, attributed to its microstructural refinement of ultrafine martensite and retained austenite. • The superior fatigue resistance and mechanical properties of AISI 301LN make it a promising candidate for critical structural components, potentially enhancing durability and performance under cyclic loading conditions. • AISI 301LN exhibited a higher fatigue strength coefficient ( = 1414.53 MPa) and a less negative Basquin slope ( = −0.0854) compared to AISI 420, indicating better resistance to fatigue at high stress amplitudes