Creep lifetime of Al 6061-T6 pressurized rotating friction stir welded tube subjected to internal pressure and rotational velocity: Welding and creep lifetime optimization

• Published in: The International journal of pressure vessels and piping 2023-04, Vol.202, p.104914, Article 104914
• Main Authors: Ahmadi Rashid, Hossein, Vakili-Tahami, Farid, Saeimi-Sadigh, Mohammad-Ali
• Format: Article
• Language: English
• Subjects: Aluminum; Creep lifetime; Failure load; Friction stir welding; Optimum
• ISSN: 0308-0161; 1879-3541
• DOI: 10.1016/j.ijpvp.2023.104914

Aluminum 6061-T6 alloys have numerous applications in the industry due to their unique properties such as higher corrosion resistance and strength-to-weight ratio. Friction stir welding is also a technique that can be used in aluminum joints because of its numerous advantages. In this paper, optimum friction stir welding parameters that lead to a higher failure load are obtained using tensile test data and analysis of variance technique. According to the analysis of variance results, it is found that the tool rotational speed has a major effect among the welding parameters on the failure load. Then, creep tests are carried out on non-welded and welded specimens to predict their creep behavior. The Norton power law equation is used as a creep constitutive equation to model the creep behavior of the specimens. The model is used to predict the creep lifetime of the welded and non-welded rotating pressurized vessels. The results show that an optimally welded vessel can only sustain up to 0.75 of pressure for the non-welded vessel with the same rotating speed. Since this comparison is not straightforward because of the number of affecting parameters. Hence, the reference stress method is used to produce a set of diagrams that provide design conditions and optimum creep lifetime for the friction stir welded Al 6061-T6 rotating pressurized vessels. •The possibility of conducting a FSW process on Al 6061-T6 has been investigated.•Optimum welding parameters which lead to specimens with a higher load-carrying capacity were obtained using the ANOVA table.•The creep behavior of parent and weld materials was studied at different temperature and stress levels.•The RSM was used to produce a set of diagrams that provide design conditions and optimum creep lifetime for the FSW Al 6061-T6 rotating pressurized vessels.