Structure of built-up edge formed in metal cutting

Abstract

The microstructure of the built-up edges of a number of alloys has been examined using both optical and electron microscopy. The built-up edges of the two ferrific steels examined showed that these were significantly different to those formed in austenitic stainless steel and Cu–40Zn brass. The built-up edge deformation system has been described using three zones: primary shear (1), deformation around the build-up (2), and deformation to form the build-up (3). The ferrific steels exhibited high-strain deformation structures in both zones 2 and 3 with structures similar to those seen in wire drawing and swaging. The stainless steel and Cu–40Zn brass, however, showed equiaxed grains about 0·2μm in size with little or no twinning in zone 3. Zone 2 of these materials showed considerable twinning and the resulting surfaces were markedly less torn than those oftheferritic steels.