The effect of flux composition on tensile strength of re-engineered E308H-16 electrode

Abstract

A stainless steel flux for manual metal arc welding (MMAW) has been developed. The coated electrode is a rutile electrode whose basic components are titanium (IV) oxide and stainless steel powder. Some of the other components were substituted; the more popular but expensive potassium silicate binder was replaced with readily available sodium silicate binder. For the binder to perform effectively, it was enriched with potassium carbonate, which was sourced locally from palm bunch. Cellulose, a good gas former was replaced with starch, which was gotten from cassava. The components were sieved into 75 µm particle size. The experimental design was set up using Central Composite Design in Design Expert software. The design varied the percentage composition of calcium carbonate, binder, titanium (IV) oxide, silicon (IV) oxide, and stainless steel powder. Twenty-six (26) test samples were produced using the central composite design tool of the design expert software and tested for tensile strength. The experimental results were analyzed and optimized using Response Surface Methodology and Validated using the ANOVA tool of the Design Expert software. An optimal composition of 10% CaCO 3 , 13% Binder, 13% Titanium oxide, 12% silicon (IV) oxide, and 36% stainless steel powder were obtained to give a corresponding 539.7 N/mm 2 tensile strength.