Properties of Ultra Low Carbon Steel Produced by Repetitive Shear Deformation of Side Extrusion

Abstract

Ultrafine grained microstructure was produced by repetitive deformation using the side-extrusion method from ultra low carbon steel with an initial grain size of about 150 μm. The repetitive deformations were imposed at a low extrusion speed of 2 mm/min at room temperature. The side-extrusions with lateral pressure were repeated up to 10 passes without rotation. The sample was uniformly deformed by the side-extrusion, and the equivalent strain was 1.15 after a single pass of the side-extrusion. The ultimate tensile strength increased from 200 MPa with an increasing number of side extrusion passes. After 10 passes of side-extrusion, an ultrafine grained steel with a tensile strength of over 1000 MPa and a grain size of 0.5 μm ×0.2 μm was developed.