Friction stir processing: An effective thermo-mechanical processing technique for carbon steels

Abstract

This review paper deals with the detailed study of published research work on FSW/FSP of different types of steels and post processing such as heat treatment effects on additively manufactured steel beads. In this context, it comprises of post processing effects on steel beads fabricated by additive manufacturing technique that includes different techniques like selective laser melting (SLM), Laser-TIG (Tungsten inert gas), Metal inert gas welding, etc. along with post processing techniques such as hot iso-static pressing (HIP), conventional heat treatment (HT), post weld heat treatment (PWHT), etc. Also, it consists of the pros and cons of FSW/ FSP, especially on low and medium carbon steels. Moreover, this paper is mainly related to the effects of friction stir welding/ processing on the evolution of microstructure, weld morphology, and temperature gradients in the processed region. In addition, there are detailed analyses of tool selection, effect of weld pitch ratio, effect of carbon content (Wt. %), and hard phase volume fraction on yield strength i.e. carbide distribution in the FSP low and medium carbon steels, and their correlation with the mechanical responses as well as crystallographic orientation relationship. Finally, based on published research, gaps are highlighted and presented as future scope of research work.