Surface alloying using PM composite electrode materials when electrical discharge texturing hardened AISI D2

The paper details experimental research on the surface modification/alloying and combined electrical discharge texturing (EDT) of hardened AISI D2 Sendzimir rolls, used for the production of stainless steel strip. Test results are presented when using powder metallurgy (PM) green compact and sintered electrodes—TiC/WC/Co and WC/Co, as a means to improve roll life and performance. Two- and three-dimensional surface roughness assessments showed the topographical characteristics of EDT samples processed using PM electrodes, to be similar to those found when using conventional copper or graphite tools, with the same pulse generator parameters. GDOES analysis showed that Ti and/or W contained in the PM electrodes, together with C decomposed from the dielectric medium during sparking, were transferred to the workpiece surface. Microhardness measurement of roll cross-sections indicated an increase in white layer hardness of ∼300 HK (0.025) when employing sintered TiC/WC/Co tools, compared with conventionally processed EDT rolls. In rolling trials using mill rolls textured with PM tool electrodes, roll/strip texture transfer measures (Ra and Pc), were consistently higher for the TiC/WC/Co textured rolls, indicating less roll wear.