Progress in welding technology of heat-resistant steel for ultra-supercritical units

In the past two decades, construction of ultra-supercritical units have been the peak period in China. Innovation and progress in power station welding technology have effectively guaranteed smooth commissioning and long-term stable operation of ultra-supercritical units in China. Weldability and welding process of ferritic heat-resistant steel and austenitic heat-resistant steel for ultra-supercritical units were reviewed, basis for revision of main standards was clarified, and development status of welding materials was pointed out. It focused on welding of new steel grade G115 for ultra-supercritical units, application of automatic welding of large thick-walled pipes with narrow gaps, minimally invasive evaluation technology of welded joints, digital technology of power station welding and other new materials, new processes and new technologies. Finally, it looked forward to development direction of China’s ultra-supercritical thermal power unit welding technology under national policy of carbon peaking and carbon neutrality, as well as challenges and countermeasures faced by safe and stable operation of welded parts under deep peak shaving of the unit.