Degradation of the creep resistance of a Re-containing 10%Cr steel upon creep testing at low applied stress

New Re-containing steel is a promising material for steam blades of fossil power plants worked at ultra-supercritical parameters of the steam. This steel was subjected to creep testing at 650°C under the applied stresses ranging from 200 to 100 MPa. The steel exhibits excellent creep resistance at high applied stresses; the time to rupture comprises 10,987 hours after the creep test at 650°C/140 MPa. However, a dramatic drop in the creep strength is observed at low applied stresses. A possible reason for this decrease in the creep resistance may be a significant coarsening of the Laves phase particles.