SURFACE MARTENSITE WHITE LAYER PRODUCED BY ADHESIVE SLIDING WEAR- FRICTION IN AISI 1065 STEEL

Abstract

White layers (WLs) produced in hard steels by adhesive sliding wear without lubricants have been characterized using microindentation, optical microscopy, scanning electron microscopy (SEM) and chemical analysis through energy dispersive spectroscopy (EDS). The WL is found to have a hardness of values ranging between 825 to 916 HV and ultrafine grained structure with layer size ranged around 50 μm. These two characteristics of white layers distinguish it from martensite structure formed in steels by heat treatment. The formation of this untempered martensite with ultrafine structure is based on a large strain deformation and stress at elevated temperature states that promote conditions of severe wear by friction.