RESIDUAL STRESS ANALYSIS OF HVOF COATING USING FE BASED APPROACH

Abstract

The scope of this project is to study the effect of coating thickness on 316L stainless steel on application of thermal cycling using finite element modeling and SEM results. Due to its ability to take high thermal loads the substrate, 316L stainless steel is commonly used in high temperature applications (power plants). But, sometime it may not sustain for the given loads. WC–Co is used as a coating material and NiAl being a good bonding layer it is used as a substrate. Hence, WC–Co/NiAl coating layers were successfully deposited on 316 L stainless steel substrates by using a HVOF technique and micro structural observations were carried out using SEM analysis. The SEM analysis revealed that the oxidation between the coating layers was very low and had very good contact with the substrate, indicating a very high bonding to the substrate. This test was carried for the thermal cycling (range 373 & 873o k) without any external load [1]. Thermal residual stresses, developed during and after thermal cycling, were determined by using FEM software package (ANSYS).It was found that the tensile stress distributions in x- direction were dominant then the compressive stresses and also the coating layer plays an important role in thermal stress