Friction stir welding of AISI 316 austenitic stainless steel sheets

Abstract

AISI 316L austenitic stainless steel is the second widely used marine grade steel in the industrial sectors like nuclear, marine, petrochemical, food processing, etc. for the fabrication of components and structures. The wide application of the AISI 316L stainless steel is owing to its unique properties and good weldability characteristics. In spite of good weldability, the fusion welded 316L stainless steel joints face the serious consequence of the metallurgical problems such as evolution of secondary phases, coarsening of grains in the heat affected zone (HAZ), hot cracking, etc. at the condition of higher heat input in a conventional welding process. The release of hexavalent chromium rich fumes and fine particles of size 0.25and#956;m, owing to the boiling of the weld pool in fusion welding process face serious consequences of health and environment related issues. Prolong exposure to such welding environments can lead to severe risk of respiratory and cancer disorders. The problem associated with higher heat input and serious risk of health disorders has compelled the researchers to explore the possibility of implementing low heat input solid state processes for the thermal joining of austenitic stainless steels. Friction Stir Welding (FSW), being one of the solid state welding processes was identified as the primitive and potential candidate for thermal joining of High Melting Temperature (HMT) materials. From the available literatures, it was found that AISI 316L stainless steels were less experimented by FSW and the comprehensive investigation on mechanical, metallurgical and corrosion characteristics of Friction Stir (FS) welded AISI 316L joints were less explored. newline