Geometrical and microstructural size effects in meso-/micro-scaled progressive forming by directly using metal wires

Abstract

Abstract A progressive meso-/micro-forming process directly using continuous wire metals is firstly developed in this work and applied for efficiently making fork-shaped parts with irregular features, e.g., flat tines and cylindrical head. Meanwhile, both geometrical and microstructural size effects on the forming quality of fabricated parts are investigated. Therein, the brass CuZn35 wires with three diameters (0.4, 0.8 and 1.2 mm) and various grain sizes (30.9-159.2 µm) are prepared and employed as the experimental materials. The material flow behavior in this progressive meso-/micro-forming process is investigated by finite element simulations and the micro-scaled specimens are found to exhibit more uniform strain distributions. As for the dimensional accuracy, the absolute errors of the thickness and width of the final parts increase with grain size, while the errors of height and inner width are only related to the precision of the punch. The increasing surface roughness after the progressive meso-/micro-forming process decreases with enlarging specimens and refining grains. Cracks easier appear on the side surface of micro-scaled specimens and specimens with the larger grain size.