L51567 Influence of Filler Wire Carbon and Residual Element Content on the Mechanical Properties

This study was conducted to determine the interactive roles of carbon, oxygen, and nitrogen and residual elements such as titanium, chromium, copper, sulfur, phosphorous, aluminum, tin, antimony, and arsenic on weld metal mechanical properties in pipeline steels. Eleven seamless, flux-core electrodes were fabricated with varying compositions and deposited in girth welds in a 24-inch diameter, API 5LX-65 pipe using the gas-metal-arc-weld (GMAW) process. The results of Charpy V-notch and crack-tip opening displacement tests indicate that desirable toughness properties may require the addition of alloying elements (e.g., nickel) that promote the formation of acicular-ferrite microstructures. In addition, small variations in sulfur content were shown to cause significant variability in notch toughness.