Effect of microstructure on pitting and corrosion fatigue of 17-4 PH turbine blade steel in chloride environments
Depending on its heat treatment, 17-4 PH stainless steel may contain significant levels of reformed austenite and untempered martensite in a matrix of tempered martensite. Shot peening can cause changes in the microstructure of the surface layers by transforming the austenite to untempered martensite. The effect of these microstructural varations on the resistance of 17-4 PH stainless steel to pitting and corrosion fatigue has been determined in simulated steam turbine environments. The results of two electrochemical tests (large amplitude cyclic voltammetry and the pit propagation rate (PPR) test) indicate that tempering temperature and shot peening have only minor effects on resistance to pit initiation and propagation in any one of three aqueous chloride environments. However, the susceptibility of this stainless steel to corrosion fatigue in one of these environments (6 wt % FeCl/sub 3/) was reduced by increasing the tempering temperature from 538/sup 0/C (1000/sup 0/F) to 649/sup 0/C (1200/sup 0/F).
- Research Organization:
- Electric Power Research Inst., Palo Alto, CA (USA)
- OSTI ID:
- 5198859
- Report Number(s):
- EPRI-RD-2284-SR; ON: DE82903139
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
STAINLESS STEEL-17-4PH
CORROSION RESISTANCE
SHOT PEENING
TEMPERING
MICROSTRUCTURE
ALLOYS
CHROMIUM ALLOYS
COLD WORKING
CORROSION RESISTANT ALLOYS
CRYSTAL STRUCTURE
FABRICATION
HEAT TREATMENTS
IRON ALLOYS
IRON BASE ALLOYS
MATERIALS WORKING
STAINLESS STEELS
STEELS
SURFACE TREATMENTS
360105* - Metals & Alloys- Corrosion & Erosion