Senior engineer, Union Carbide Corp., South Charleston, W. Va.
Pages: 14 Published: Jan 1980
The objective of the testing program was to evaluate the toughness of the welds in high-purity 26Cr-1Mo ferritic stainless steel. The method used to determine the toughness was by bursting heavy-walled pipe. The burst specimens incorporated a longitudinal through-thickness weld that contained a machined notch part way through the wall thickness. A burst test specimen geometry was developed which tested the weld, heat-affected zone (HAZ), and base metal at the same time. Successful welding was done using the gas tungsten-arc welding (GTAW) method and an argon purge. The results of the investigation showed that the 26Cr-1Mo weld deposit and HAZ were brittle at room temperature. The welds were then made of a root pass of 26Cr-1Mo followed by filler passes of Hastelloy C-276 and a postweld heat treatment. The results of the composite welded specimens showed that the weld was now tough, because of the Hastelloy C-276, while the HAZ had a ductile-to-brittle transition temperature between room temperature and 65°C (150°F). The specimens were evaluated by visual characterization of the fracture appearance.
ferritic stainless steels, gas tungsten-arc welding, welding electrodes, brittle fracturing, burst tests, evaluation, impact tests, pipe, toughness, fracture (materials), fracture toughness
Paper ID: STP38211S