LASER-SURFACE HARDENING OF GRAY CAST IRONS

Three different ferritic-pearlitic gray cast irons have been laser har dened. The influence of laser power density and scanning speed on thei r microstructural modification, affected depth and surface hardness ha ve been evaluated. It was observed that when the laser energy density surpasses a certain critical value, a surface layer melts and a ledebu ritic microstructure of very high hardness is obtained. Below it, a se cond layer of martensitic microstructure also of high hardness, is pro duced.