Effect of friction stir processing on the mechanical properties of gas metal arc welded AISI 409 L stainless steel plate

• Published in: Materials today communications 2024-12, Vol.41, p.111075, Article 111075
• Main Authors: Gupta, Sanjay Kumar, Mahto, Mithlesh Kumar, Raja, Avinash Ravi, Vashista, Meghanshu, Yusufzai, Mohd Zaheer Khan
• Format: Article
• Language: English
• Subjects: Ferritic stainless steel; Friction stir processing; Gas metal arc welding; Mechanical properties; Processing speed; Rotational speed
• ISSN: 2352-4928; 2352-4928
• DOI: 10.1016/j.mtcomm.2024.111075

Gas metal arc welding of ferritic stainless steel (AISI 409 L) is widely carried out in industries. However, the grain coarsening in the heat affected zone is a serious issue which causes reduction in the strength of the welded plates. In this study, an attempt has been made to refine these coarse grains by using friction stir processing in order to improve the mechanical properties of the welded plates. Efforts have been made to investigate the impact of the ratio of tool rotational speed to processing speed on grain size and mechanical properties. The welded and subsequently processed plates have been analyzed for their integrity and microstructure. The properties of the welds, both before and after friction stir processing; have been evaluated through hardness testing, tensile testing, and residual stress assessment. It was observed that the coarse grains of the heat affected zone of the gas metal arc welded plate have been refined through friction stir processing operation which ultimately improved the mechanical properties. On increasing the rotational speed to processing-speed ratio, the grain size in the processed region as well as thermo-mechanically affected zone decreased resulting in higher hardness at those combinations of process parameters. The nature of residual stress in the weldmetal was tensile in nature after gas metal arc welding. However, after friction stir processing, compressive residual stresses were achieved. [Display omitted]