Effect of Continuous Extrusion Parameters on Alloy M1 Round Section Bar Microstructure and Mechanical Property Formation

Results are provided for microstructural evolution and mechanical property formation in a deformation zone during continuous extrusion, and the effect of extrusion rate parameters on the properties of M1 grade copper rods is also evaluated. The study is conducted on butt-ends and bars obtained in a Conform 350 industrial unit. Investigation of metal flow in the deformation zone shows that features of structure transformation are retained for all specimens. A cast (undeformed) billet has a structure with a large grain size (80-1000 mu m). As a result of extrusion a workpiece structure grain size is reduced to 50-35 mu m. Quantitative data are obtained for the formation of finished product hardness in relation to equipment configuration and extrusion parameters. Samples extruded at a rate of 6 m/min have an optimum hardness level (62.5 kgf/mm(2)) that satisfies the standard specifications, unlike other samples extruded at a slower rate.