Similar and dissimilar rotary friction welding of steels: A review of microstructural evolution and mechanical properties

Abstract

Rotary friction welding is widely utilized in similar and dissimilar welding of alloys such as magnesium and aluminum alloys, steels, and superalloys. The maximum temperature of the joint and welding defects in this method are lower than in any fusion-based welding process. Hence, it is feasible to join dissimilar metals with completely different properties. However, there is a great possibility for the formation of brittle compounds, carbides, and intermetallic phases, especially in dissimilar welding of carbon steels to stainless steels, and also in similar welding of stainless steels. This article aims to investigate the influence of RFW process parameters on the microstructure and the mechanical properties of the joints. The main parameters of this process include friction time, friction pressure, forging time, and forge pressure. Each of the aforementioned parameters influences the amount of plastic deformation and heat input, which ultimately affects the microstructure's evolution. The mechanical properties of the joint in RFW are enhanced by recrystallized grains, refined grain size, and the controlled dispersion and removal of inclusions and carbides. The joining of steels by the RFW method is often accompanied by microstructural inhomogeneity, residual stress, discontinuity, flash, and the formation of undesired phases due to excessive heat at the joint section. Therefore, a thorough review should be conducted regarding the relations between the welding parameters optimization, microstructural evolutions, and mechanical properties. Additionally, it is necessary to address the phase formation mechanisms and the ways to prohibit the formation of undesirable compounds during the RFW process using post-weld treatment.

Keywords

• Steel welding
• Similar welding
• Dissimilar welding
• Rotary friction welding
• Friction welding