Improved fatigue wear resistance of gray cast iron by localized laser carburizing

The aim of this experimental study is to improve gray cast iron fatigue wear resistance through laser cladding carbon - a proposed process referred as “laser carburizing”. Optimization of laser carburizing processing conditions is achieved by studying the effects of input energy density on sample fatigue wear resistance. Following laser deposition, details of treated regions are experimentally investigated and compared. Fatigue wear tests are separately executed in an air atmosphere. Results demonstrate that laser carburizing is a more effective means of improving fatigue wear resistance than laser remelting and that the improvement is significantly affected by increase in energy density during treatment. Examinations of worn surface reveal the mechanisms of improvement: the unit not only removes the source of crack initiation, but also eliminates the bridging of cracks throughout the material. To further understand the mechanisms of fatigue wear resistance improvement, contact stresses distributions on sample surfaces are predicted using Finite Element Analysis.