TRIP effect produced by cold rolling of austenitic stainless steel AISI 316L

This study aims to study the transformation-induced plasticity (TRIP) by cold rolling in AISI 316L grade ASTM F138: 2019 (biomedical material) and its compliance with ISO 5832. The cold rolling of 316L is less expensive and gives a good surface finish and dimensional deviations as compared with casting, powder metallurgy, additive manufacturing, and forging. However, the cold working processes of 316L stainless steel can produce unwanted phases by the TRIP effect that limits its use as a biomaterial according to ISO. Understanding the TRIP effect of 316L by cold rolling can help to become more accessible to biomedical engineering applications. To evaluate the TRIP effect on cold-rolled 316L steel under conditions of low thickness reduction (deformation) of 10, 20, and 30%, mechanical, electrochemical, morphological, magnetic, and crystallographic analyses were performed. Crystallographic analysis by X-ray diffractograms indicated the presence of martensitic crystalline phase α’ for samples with 20 and 30% thickness reduction, which was also verified by metallographic, Vickers microhardness, and ferritoscopy tests. Based on the results obtained, the reversion treatment is recommended for cold conformations in 316L steel as a metallic biomaterial greater than 10% thickness reduction.