Weld metal, coke drum and bond flux obtained by submerged arc welding of 1.25 Cr-0.5 Mo steel

摘要

A high-quality submerged arc weld metal for 1.25 Cr-0.5 Mo steel that is obtained by carrying out multi-pass welding in a submerged arc welding process with a solid wire and a bonded flux being combined together, is produced in which a strength mismatch with a base material does not occur even after a Post Weld Heat Treatment is carried out for a short time to a long time, and which has high ductility as well as having no weld defect. The submerged arc weld metal for 1.25 Cr-0.5 Mo steel is characterized in that: the weld metal contains, per the total mass of the weld metal, C: 0.06 to 0.12 mass %, Si: 0.15 to 0.30 mass %, Mn: 0.60 to 1.10 mass %, Cr: 1.10 to 1.45 mass % and Mo: 0.45 to 0.60 mass %, wherein O is contained in an amount of 0.022 mass % or less and N is contained in an amount of 0.008 mass % or less, and wherein the balance is Fe and inevitable impurities.