Chemistry and microstructure of duplex stainless steel powders from recycled Z100 mixed with 316L steels

• Published in: Archives of Civil and Mechanical Engineering Vol. 23; no. 4; p. 246
• Main Authors: Kateusz, Filip, Polkowska, Adelajda, Polkowski, Wojciech, Chrzan, Konrad, Jaśkowiec, Krzysztof, Sokołowski, Paweł, Igartua, Amaya, Leunda, Josu, Bisztyga-Szklarz, Magdalena, Dudziak, Tomasz, Jedliński, Jerzy
• Format: Journal Article
• Language: English
• Published: London Springer London 11.10.2023; Springer Nature B.V
• Subjects: Austenite; Chemical composition; Civil Engineering; Copper; Corrosion resistance; Corrosion tests; Delta ferrite; Diamond pyramid hardness; Dislocation density; Duplex stainless steels; Energy consumption; Engineering; High temperature; Manufacturing; Mechanical Engineering; Mechanical properties; Microstructure; Modulus of elasticity; Original Article; Oxidation; Particle size; Phase transitions; Raw materials; Recycling; Stainless steel; Steel industry; Structural Materials; Ferrite austenite transformation; Duplex stainless steel; Powder feedstock; Recycling; Rapid solidification
• ISSN: 1644-9665; 2083-3318; 1644-9665
• DOI: 10.1007/s43452-023-00782-9

Recovered metallic waste can be used in additive manufacturing as a feedstock if the subsequent steps of the waste-to-product process are sufficiently mastered. In this study, impact of recycling of Z100 duplex steel mixed with 316L steel on the resulting powders microstructure and chemical composition was investigated. The utility of the original method of recycling stainless steels into a high-grade powder suitable for additive techniques has been demonstrated. By examining three gradations of powders, namely 20–50 μm, 50–100 μm and 125–250 μm, differences in selected properties in relation to the average particle size are shown. The results suggest that with increasing the particle diameter, fine-crystalline γ-austenite is favoured to precipitate at the boundaries and within the volume of the originally formed large δ-ferrite grains. It is reflected by a decrease of δ/γ fraction ratio from 0.64 in the 20–50 μm powders to 0.20 in the 125–250 μm, respectively. Obtained results indicate non-diffusional, shear or semi-shear character of δ → γ + δ phase transformation. The resulting fine-crystalline austenite is characterised by a significant dislocation density, which induces dislocation strengthening effect, responsible for an increase in Vickers hardness from 145 HV and Young's modulus from 29 GPa in the 20–50 μm group to 310 HV and 146 GPa in the 125–250 μm fraction, respectively.