Experimental and Numerical Study on the Effect of Strain Hardening Characteristics on Curved Flaring Process of Pure Copper and Brass

Abstract

An experimental and numerical study of tube curved flaring process was conductedto investigate the effect of strain hardening characteristic of material on the processusing two metals that differ in strain hardening characteristic which are pure copperand brass (70-30) by using curved dies which have curvature ratio ( ρrd) of (ρrd=6)and (ρrd=12) and base radius of die (rd=24mm) and (ρ) is the radius of curvature.The experimental part was included experiments on specimens with an outerdiameter of (39 mm) and a wall thickness of (2 mm). The expansion process wascarried out for different expansion ratios that it was reached to about (32%). Theresults were showed that the strain hardening exponent of pure Copper more thanBrass (70-30) and its value reached (0.54) for pure Copper and (0.49) for Brass(70-30). However, this paper concluded a study of the effect of strain hardeningcharacteristics on the curved flaring process. It was found that the increasing offlaring ratio and relative axial displacement of the die through the specimen arecaused increase in the relative forming stress, and its value is significant inexpanded tubes with high strain hardening characteristic and it is about (0.77) inBrass and (1.42) in Copper. It also found that a little difference in the deformationof specimens' geometry which means that the deformation is not affected by thestrain hardening characteristic and there is no significant difference in straindistribution. The study also included a numerical simulation using the finiteelement ANSYS program. The results obtained are compared with experimentaldata and showed good agreement.