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 conducted to investigate the effect of strain hardening characteristic of material on the process using two metals that differ in strain hardening characteristic which are pure copper and brass (70-30) by using curved dies which have curvature ratio ( ρ rd ) of (ρ rd =6) and (ρ rd =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 outer diameter of (39 mm) and a wall thickness of (2 mm). The expansion process was carried out for different expansion ratios that it was reached to about (32%). The results were showed that the strain hardening exponent of pure Copper more than Brass (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 hardening characteristics on the curved flaring process. It was found that the increasing of flaring ratio and relative axial displacement of the die through the specimen are caused increase in the relative forming stress, and its value is significant in expanded tubes with high strain hardening characteristic and it is about (0.77) in Brass and (1.42) in Copper. It also found that a little difference in the deformation of specimens' geometry which means that the deformation is not affected by the strain hardening characteristic and there is no significant difference in strain distribution. The study also included a numerical simulation using the finite element ANSYS program. The results obtained are compared with experimental data and showed good agreement.