Weldability of Accelerated-Cooled (AcC) High Strength TMCP Steel X80

摘要

The report gives and briefly discusses the test results obtained in welding andweldability tests of an accelerated-cooled pipe-line steel AcC X80. The tests comprised of mechanical testing of joints welded with arc energies ranging from 15 to 50 kJ/cm using SAW and FCAW processes. Also the results of weld thermal simulation and Implant weldability tests for the steel are reported and discussed. The results demonstrate the improved weldability of the AcC X80 steel, as compared to conventional normalized or QT steels of similar strength level. Even in heavily restrained butt-welded joints representing the most severe conditions in pipe-line field welding, welding without preheat was possible up to 15 and 25 mm plate thickness using arc energies of 10 and 22 kJ/cm, respectively. In the majority of cases, all the welded joints failed to meet the toughness requirement (40 J/-40C) all through the arc energy range from 15 to 50 kJ/cm. Adequate heat affected zone impact toughness was obtained only in one of the joints welded with a low arc energy of 15 kJ/cm. Weld metal toughness was acceptable, although a decrease in toughness was evident towards higher heat inputs.