Oxidation Behaviour of Welded ASTM-SA210 GrA1 Boiler Tube Steels under Cyclic Conditions at 900°C in Air

Abstract

Abstract ASTM-SA210-Grade A1 boiler tube steels were welded by shielded metal arc welding (SMAW) and tungsten inert gas processes. The oxidation behaviour of the welded steels was evaluated under cyclic conditions at 900°C. Visual observations and thermogravimetric data were measured at the end of each cycle. Finally, the scale was analysed using X-ray Diffraction, Scanning-Electron Microscopy/Energy-Dispersive X-Ray studies. A SEM Back scattered image analysis of the cross-section of the oxide scale thickness has been made to measure the oxide scales formed over the welded steels. SMAW welded steel showed the more oxidation rate (in terms of weight gain) as compared to TIG welded at the test temperature of 900°C and it was due to the formation of more cracks in oxide scale, and a thick oxide scale was found on HAZ and weld region.