Brass H62 Hot Extrusion of Micro Gear

Abstract

Gears are very important and widely used driving components in mechanical instruments, and the demands of micro-gears are increasing more and more active as the MEMS technology develops in recent years. In this paper, a brass micro gear, which modulus m = 0.125 mm, pressure angle α = 20°, number of teeth z = 6, addendum circle diameter d = 1 mm, hot extruded from brass H62 billet with size Φ3×3 mm at 650°C was studied by experimental method. The microstructure of the micro gear was observed by scanning electron microscope and optical microscope, and the conclusions are as follows: the fiber flow lines within the micro-gear were formed by the extrusion, so that the anisotropic mechanical properties of the micro-gear was happened; The tissue distribution of micro-gear was that, the surface of the gear is almost entirely α-phase, while the internal part of the gear was the mixture of α-phase and β-phase, because the α-phase with lower hardness flowing outward to the surface of the gear during the extrusion process.