Microstructure and mechanical properties of UNS N10003 alloy welded joints

Abstract

Microstructure and mechanical performance of the welded joints of UNS N10003 alloy have been investigated in this work. Primary precipitates in base metal and eutectic precipitates in Heat Affected Zone (HAZ) and weld metal have been characterized and identified as M6C type. The hardness value of HAZ (Eutectic zone) is significantly higher than the rest of joint, including weld and base metal. Tensile tests suggested the welded joints possess a very stable mechanical performance at elevated temperature from 650 °C to 725 °C. Moreover all the tensile samples were fractured in base metal, indicating that the eutectic carbides have no adverse effects on the short-time mechanical performance of joint. The fine carbides, acting as dispersion strengthening in weld metal, are main contribution to enhance the hardness and strength of weld. The good mechanical performance of HAZ is ascribed to the presence of eutectic carbides and twins.