High Temperature Creep Behavior of Overage Serviced 10CrMo910 Steel forPower Station

The high temperature creep tests at different temperatures (535,560,580℃) were conducted on 10CrMo910 steel main steam pipe for generator unit in a thermal power station, which had been running for more than 2×10⁵ h, and the high temperature creep behavior and microstructure evolution of the steel were studied. The results show that after high temperature creep at different temperatures, the grains of overage serviced 10CrMo910 steel were obviously deformed, recrystallization occurred in bainite and ferrite matrix, and precipitates coarsened; creep holes became larger and deeper, and creep damage was aggravated. With increasing creep temperature, the creep fracture time decreased from 4 633 h to 2 314 h, and the high temperature creep rupture strength decreased from 87.7 MPa to 58.3 MPa, indicating the high temperature creep property of 10CrMo910 steel decreased. The creep fracture was dimple-like without obvious shear tear zone and with obvious secondary cracks and precipitates, and the fracture mode was quasi cleavage fracture.