Application of SPT on SA-335P91 Steel Used For High-Temperature Components of Utility Boiler

Abstract

Abstract To further develop the application of SPT in the life assessment for high-temperature components of utility boiler, this paper analyses the microstructure of the common steel of SA-335P91 with the treatment of high temperature aging by OM, SEM, EDS and XRD, tests the normal tensile properties and the mechanical properties from SPT, and studies the relationship of the two kinds of mechanical properties. The results shows, after high temperature aging with 630-640°C×3000h of SA-335P91 steel, the size of precipitate in the microstructure grows from small to big, the number from many to a few, the distribution from grain inner and boundary to only boundary, and the tensile strength and yield strength of materials display the downtrend. More than ever, the experiments demonstrate the SPT is scientific, reasonable and feasible in non-destructive testing and the life assessment of SA-335P91 steel using in utility boiler, and the two fitting formulas are: σ s=0.5398Py /t2–49.456; σb =0.0732P max/t0 2 +105.59.