Effect of electro discharge machining EDM on the AISI316L SS white layer microstructure and corrosion resistanceReport as inadecuate

Effect of electro discharge machining EDM on the AISI316L SS white layer microstructure and corrosion resistance - Download this document for free, or read online. Document in PDF available to download.

1 Laboratoire de Mécanique, Matériaux et Procédés - ESSTT, Université de Tunis 2 UNAM - Universidad Nacional Autónoma de México 3 PIMM - Procédés et Ingénierie en Mécanique et Matériaux Paris

Abstract : The localised corrosion resistance of austenitic stainless steels is strongly influenced by the quality of finished surface. EDM machining induces substantial changes by the high thermal gradients generated by electric sparks. Experimental techniques such as roughness measurement, scanning electron microscopy SEM, energy dispersive microanalysis EDX and X-ray diffraction technique, reveal microgeometrical, microstructural, chemical and mechanical changes. These changes lead to white and heat-affected layers with a depth less than 100 μm. The white layer is a melted material characterised by dendritic structure and constituted by austenite, chromium carbide and ε-carbide. The heat-affected layer is characterised by very large grain size comparatively to the bulk material. Electrochemical test coupled with metallographic examinations using SEM reveals a weakening of the resistance to pitting and intergranular corrosion comparatively to diamond polished surface. This weakening is correlated to differences in structure and chemical composition of white layer. Susceptibility to stress corrosion cracking has been attributed to the field of tensile residual stresses resulting from thermal effects. The removal of the white layer material by polishing or wire brushing restores the corrosion resistance of the AISI316L SS.

Keywords : Corrosion Surface Microstructure White layer Residual stress

Author: Habib Sidhom - Farhat Ghanem - Tidiane Amadou - Gonzalo Gonzalez - Chedly Braham -

Source: https://hal.archives-ouvertes.fr/


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