Author/Authors :
ŞEŞEN, Fikri Erdem Istanbul Technical University - Faculty of Chemical and Metallurgical Engineering, Turkey , ÖZGEN, Ömer Serdar Istanbul Technical University - Faculty of Chemical and Metallurgical Engineering, Turkey
Abstract :
Boronizing is one of the primary surface hardening methods that have been applied for several decades in order to increase the service life of components, tools and equipments made mainly of ferrous alloys. It is a thermochemical surface diffusion treatment which includes adhesion and penetration of boron atoms supplied from a source that can be in solid, liquid, gas or even plasma states. Though boronizing has been applied to many alloy systems including all ferrous alloys, titanium alloys, nickel alloys, cobalt alloys, refractory metal (chromium, molybdenum, vanadium, niobium, tantalum, tungsten and zirconium) alloys, etc., no studies exist in the literature on boronizing of an Interstitial-Free (IF) steel. In this work, IF steel, possessing very little amount of alloying elements, was boronized by electrothermochemical method. Boronizing treatment was carried out at 900 and 1020 °C temperatures for durations between 15 and 90 min by applying current densities between 0.05 and 0.40 A/cm² in dehydrated sodium borax bath. The boride phases of Fe2B, FeB, Fe3B and Fe3.5B were formed as a result of the boronizing treatment. Boronizing treatment at 1020 °C for 45 min by applying a current density of 0.20 A/cm² caused the formation of a boride layer with a thickness of 135 μm. Diffusion mechanisms and mechanical properties of the layers formed by boronizing treatment were investigated by means of microstructure and phase analysis and hardness measurements.
