Experimental investigation on SMAW electrode coatings developed using CaO–SiO2–CaF2–SrO based coating system

Abstract

This research aims to provide a SMAW electrode coating developed using a CaO–SiO2–CaF2–SrO flux system for welding the components of an advanced ultra-supercritical power plant. The physicochemical and thermophysical characteristics of developed coatings were investigated. Twenty-one distinct electrode coating formulations were developed using the extreme vertices technique. Experiments for several thermophysical and physicochemical characteristics were carried out. The coating's qualities are critical for producing a strong weld that will last in the field. X-ray diffraction and Infrared spectroscopy were used to examine the structural behavior of the electrode coatings. Furthermore, the regression model was developed to explore the effect of coating compositions. The primary constituents and their interaction have an influential role in physicochemical and thermophysical characteristics. Individual and ternary mixtures significantly affect the density. CaO.SiO2.SrO and CaF2·SiO2·SrO is the most effective ternary mixture, which has an increasing effect on density. The weight loss of coating observed during thermogravimetric analysis is affected by individual constituents significantly. The ternary mixture CaO·CaF2·SiO2, CaO·CaF2·SrO, and CaF2·SiO2·SrO is the most favorable and has an increasing effect on weight loss. Individual constituents affect change in enthalpy significantly. The thermal properties of coating observed during hot disc are affected by binary and ternary mixture constituents. Binary mixture CaO·SiO2 is having an increasing effect on thermal conductivity. Binary mixture CaO·SrO and SrO containing ternary mixture have an increasing impact on thermal diffusivity. Ternary mixture constituents CaO·CaF2·SrO, CaF2·SiO2·SrO is the most effective and has an increasing effect on specific heat.