Improving Fretting Fatigue Strength at Elevated Temperatures by Shot Peening in Steam Turbine Steel

Abstract

Fretting fatigue tests at elevated temperature were carried out using shot-peened specimens to improve the high temperature fretting fatigue strength of 12Cr-Mo-W-V steam turbine steel. Shot peening improved fretting fatigue strengths by a factor of 1.8 at an elevated temperature (773 K) as well as at room temperature. Residual compressive stresses first drop rapidly by a factor of three and then level off. Residual compressive stresses of 200 MPa were measured after a 30 000 h exposure at 773 K. Shot peening is thus shown to be effective over long periods at 773 K.

Investigation into effects of re-shot-peening on fretting fatigue behavior of Ti–6Al–4V

“…The compressive residual stress on the surface can prevent crack initiation and propagation as well as close pre-existing cracks when they are within the depth of compressive zone. It has been shown in previous studies that shot-peened components have longer fatigue lives as compared to un-peened components under various fatigue situations [4][5][6].…”

Fretting fatigue behaviour of shot‐peened Ti‐6Al‐4V at room and elevated temperatures

“…Thus various surface treatments have been developed for enhancing the fatigue life of components. Shot‐peening is one of the most widely used surface treatments in the industry to improve fatigue strength of metallic parts and several studies have shown that shot‐peening improves the fretting fatigue strength of materials 5 , 7–9 . Shot‐peening induces a residual compressive stress on the surface and a compensating residual tensile stress within the materials.…”

“…E-mail: shankar.mall@afit.edu treatments in the industry to improve fatigue strength of metallic parts and several studies have shown that shot-peening improves the fretting fatigue strength of materials. 5,[7][8][9] Shot-peening induces a residual compressive stress on the surface and a compensating residual tensile stress within the materials. Consequently, residual stress profile changes with depth from the surface.…”

Comparison of electromagnetic inspection methods for creep-degraded high chromium ferritic steels

“…Clear distinctions can be made between samples of the same category. The more interesting MIP factor was the correlation between the derived magnetic parameters from these curves and the microstructural information [10]. The MIP showed a stronger correlation.…”

“…High-chromium ferritic steel (12% chromium steel) is used commonly for high-temperature power plant components, such as steam turbine rotor blades and gas turbine compressor blades [10]. Chromium is used frequently to increase the resistance to corrosion and erosion.…”