Effect of Microstructure on Pitting and Corrosion Fatigue of 17-4 PH Turbine Blade Steel in Chloride Environments

Corrosion fatigue behaviour of a 15Cr‐6Ni precipitation‐hardening stainless steel in different tempers

“…Both high-cycle axial The limited number of previous investigations 4,11,[14][15][16] discussing CF behaviour of 17-4 PH steels were mainly fatigue and FCG tests were carried out in laboratory air and an aerated 3.5 wt% NaCl solution at room tempera-based on either high-cycle fatigue or fatigue crack growth (FCG) experimental results. Both high-cycle axial The limited number of previous investigations 4,11,[14][15][16] discussing CF behaviour of 17-4 PH steels were mainly fatigue and FCG tests were carried out in laboratory air and an aerated 3.5 wt% NaCl solution at room tempera-based on either high-cycle fatigue or fatigue crack growth (FCG) experimental results.…”

The effect of pit size and density on the fatigue behaviour of a pre‐corroded martensitic stainless steel

“…2 While classified as a stainless steel, the relatively low PREN number (17.5 based on the max nominal composition) 3 facilitates a propensity for in-service corrosion damage in aqueous chloride environments. Due to its high strength and moderate corrosion resistance, PH17-4 steel is often used for turbine blades in both the utilities and aerospace industry.…”

“…4 Pitting of stainless steels [5][6][7][8][9][10][11][12] (specifically, of precipitation hardened martensitic stainless steels [13][14][15] ) in chloride environments has been extensively studied. 3,15,26,27 Two engineering considerations motivate the investigation of the factors that govern the crack formation Nomenclature: CL1, Corrosion level 1 (severe corrosion); CL2, Corrosion level 2 (moderate corrosion); UNS S17400, 17-4 martensitic steel process from a broadly corroded surface. 11 Generally, this process is nucleated by an environment-induced rupture of the stable passive film 7,24,25 followed by an autocatalytic process (metal dissolution, hydrolysis, and anion ingress to the pit for charge neutrality) that creates the local aggressive chemistry necessary for continued dissolution.…”

“…5,7,8 Localized damage such as pitting is highly deleterious to the fatigue resistance of engineering components, which has motivated significant research into how such damage affects the fatigue life of PH17-4 steel . 38,[40][41][42] ) Such approaches do not reflect reality and tend to be highly conservative 28 ; specifically, fracture mechanics approaches assume a 2-dimensional and sharp morphology, whereas pits are 3-dimensional (tending to be hemispherical and smooth in this class of steels 3,5,6,15,[43][44][45]. First, linear elastic fracture mechanics (LEFM) models have been proposed as a means to predict the remaining life of corroded components; such modelling would enable informed maintenance actions and enhanced ability to mitigate failures.…”

The interaction of corrosion fatigue and stress-corrosion cracking in a precipitation-hardened martensitic stainless steel

“…7,8 Despite these attributes, high-strength steels are highly susceptible to environmental cracking in aqueous chloride environments. Specifically, researchers have demonstrated aqueous chloride environments can: induce localized corrosion damage [9][10][11][12] causing a severe reduction in overall fatigue life, 10,[13][14][15][16][17][18][19][20][21] accelerate fatigue crack-growth rates, 13,16,[21][22][23][24][25][26][27] and enhance susceptibility to stress-corrosion cracking (SCC). 21,28 Enhancement of the environmental cracking kinetics is widely attributed to hydrogen embrittlement (HE).…”