Experimental investigation of the effect of processing parameters on mechanical properties and dimensional changes of warm flow formed 6061 aluminum alloy tube

The flow forming process is widely used in the production of axisymmetric industrial parts. The advantage of the flow forming process over other manufacturing methods is the use of simple tooling, reduced forming loads due to localized deformation, and enhanced mechanical properties and surface quality of finished parts. In this research, the warm flow forming process of AA6061-O aluminum alloy has been investigated for the first time. For this purpose, laboratory equipment and samples were designed and fabricated. In this study, the effect of temperature, thickness reduction, and number of passes (number of forming steps) on dimensional accuracy (thickness variation) and mechanical properties of warm flow formed AA6061-O alloys pipes have been experimentally investigated. The experimental results show that flow forming increases the strength and decreases the ductility of the formed pipe at all process levels compared to the initial non-flow forming pipe. However, the ductility of the pipe increases and its strength and microhardness decrease by increasing the forming temperature from 20 to 300 ° C. While with increasing the percentage of thickness reduction from 20% to 60% at a constant forming temperature, the strength and micro-hardness of the warm flow-formed pipe increases and its ductility decreases.