Experimental research on Annular Welded Joints with large gap of steel girder

For girder large gap assembly welding (30mm) issue caused by girder position and configuration when steel girder bridge site erection process, Adopting backing ceramic liner with CO2 gas shielded welding and one-side welding with back formation technology to carry out two process position welding process test for Annular and closed box girder Welded Joints. Through Y slit type groove cracking test to determine preheat temperature under large gap and strong constrain conditions. Based on complex changes of Material organizations characteristic caused by multi-frequency and wide range overheating in heat affected zone under large gap welding, focusing on the low temperature impact toughness and cold cracking susceptibility outside fusion line of 1, 3, 5 mm Though ultrasonic testing and mechanical properties and metallographic structure analysis of welded joint to vertify the process feasibility with large gap welding and provide test support for real bridge welded joints.