Sheffield Forgemasters announced a breakthrough in the industrialization of electron-beam welding (EBW) for thick-section materials. Using EBW, the company weld-joined two 200-mm-thick (8-inch-thick), 3-meter-diameter (9-foot-diameter) forged vessel sections of nuclear-grade steel. The weld, equivalent to approximately 10 meters (32 feet) in length, was completed in a single pass and in a dramatically short timeframe. The weld was completed in 140 minutes with no reportable defects shown in preliminary nondestructive testing (NDT). A weld of this kind would typically take months and include numerous stages of NDT and heat treatment, according to U.K.-based Sheffield Forgemasters.
Sheffield Forgemasters aims to incorporate advanced fabrication techniques, which will provide significant savings on both processing time and cost through the potential of EBW over the more traditional method of tungsten inert gas welding for thick-section pressure vessels. The EBW process uses local vacuum and a high-power electron gun, which penetrates the vessel material with an electron beam, to melt and fuse the two components together in one pass rather than building up multiple layers of weld filler wire.
“We are due to start building an X-ray enclosure to house the EBW equipment, and it will be ready during the second quarter of 2022,” said senior development engineer and project lead Dr. Michael Blackmore. “We are also planning to fully demonstrate the welding capabilities by fabricating a full-scale nuclear pressure vessel that will consist of five main components – four shells and a nuclear head – to ensure a reliable and repetitive process.”