Experimental and numerical study of expanded aluminum and steel tubes

This paper presents the design of an experimental set-up to mechanically expand aluminum and steel tubes using conical hardened steel mandrels. The experimental study considered four radial expansion ratios of 10, 15, 20 and 25% and three mandrel angles of 10, 22.5, and 30 degrees. The effect of the expansion ratio and mandrel angle on the tubes wall thicknesses and drawing force required to expand the tubes. The experimental study was supplemented by finite element models reflecting the lab tests to determine the drawing force. The finite element analysis took into consideration the same parameters treated experimentally. The simulation results, which were calibrated through generated experimental data, used to study the effect of tubes expansion ratios and mandrel angles on the stress level for the two types of tube materials. It was found that the drawing force and stress levels in expanded steel tubes are much higher than the ones in aluminum tubes; thereby, require more power to conduct the expansion process.