Characterization of different surface layers produced by solid boron-nitro-carburizing thermochemical treatment on AISI 1020

Abstract

The aim of this study is to obtain and characterize surface layers on low carbon steel with the pack boronnitro-carburizing process. Different mixtures of commercial powders (Turbonit® and Ekabor®) were used to investigate the case properties, microstructure and phases formation on AISI 1020 steel. A series of experiments were conducted in solid medium with powders blend, with weight proportions of 0/100;25/75;50/50;75/25;100/0 at temperatures of 1000 and 1100° C for 2 and 10 hours. Roughness measurement of all treated specimens was assessed to compare with pre-treatment condition. Hardness profle and comparative analysis of phase structure, morphology and composition was carried out to treatment conditions. Optical microscopy shows di?erences on layers surface, depth and microstructure case-di?usion zone. Results found indicated that for the same treatment time and temperature, hardness was changed, but the di?usion case depth was kept similar. DRX and XPS indicated the formation of boron nitride after certain treatments.