High-temperature wettability study of mineral waste added CaO–CaF₂–SiO₂ and CaO–TiO₂–SiO₂-based electrode coating for offshore welds

Abstract

This paper investigates the high-temperature wettability property of the mineral waste red ochre added CaO–CaF2–SiO2 and CaO–TiO2–SiO2-based electrode coating mixture for offshore welding. The extreme vertices design method was applied to formulate 21 coating compositions. The pellets made from developed electrode coating compositions were exposed to a high temperature of 1250℃ on the substrate of super duplex stainless steel of 2507 grade. The molten flux has been characterized for contact angle, surface tension, adhesion energy and spreadability. The regression analysis has been used to estimate the effect of individual components and their interactions on the wettability property parameters. The developed regression models have been optimized using multiresponse optimization to achieve optimum flux composition. Structural analysis of flux mixture has been done using X-ray diffraction and Fourier transformation spectroscopy.

Framework for incorporating stakeholders’ preferences in lifecycle welding flux design

“…The interest of the welding flux design community in the application of multi-criteria optimisation methods to welding flux design has been on the increase since the appearance of these papers. However, only the DF approach has received significant attention out of the five methods suggested for achieving optimal flux formulation [5][6][7][8][9][10][11].…”

“…Most of the papers that have appeared to date rarely consider the opinion and preferences of the WFS on the intensity of importance they attach to the various welding flux quality requirements [5,[11][12][13][14]. The investigators who did not completely overlook the preferences of the WFS presumed that all design criteria are of equal importance to the WFS [6][7][8][13][14].…”

“…For instance, some investigators limit their studies to the operational characteristics of the flux. This is only related to the time when the flux is used for welding, while some concentrate on the ability of the flux to produce weldment that will meet service requirements such as mechanical, microstructural and chemical properties [5][6][7][8][9][10][11][12][13][14][15][16]. Studies that consider the lifecycle of flux and incorporate the needs and desires of all WFS covering the entire lifecycle such as manufacturing, storage and transport, use, welder's health, and weld-metal quality simultaneously are not common in the open literature.…”

Current trends in welding flux development

“…Recycling of fused slag has been suggested as a means of reducing cost of welding flux [4]. The desire to reduce cost has intensified research activities in welding flux development using the waste-to-wealth philosophy [5][6][7][8][9].…”

“…Minerals required for the manufacture of welding flux such as calcite, cryolite, rutile, fluorspar, dolomite, quartz, wollastonite, alkaline carbonates and silicates are non-renewable resources and they are getting depleted fast. A lot of research activities are directed towards the development of recycling technology that allows the use of slag as fresh flux to mitigate the above problems and also reduce the total cost of welding [3,6,7,9]. A lot of dust (between 10 and 15% of the flux) is generated during the handling and transportation of flux [5].…”