Chloride-Induced Stress Corrosion Cracking of Austenitic Stainless Steel David Spencer 3rd Year PhD...
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Transcript of Chloride-Induced Stress Corrosion Cracking of Austenitic Stainless Steel David Spencer 3rd Year PhD...
Chloride-Induced Stress Corrosion Cracking of
Austenitic Stainless SteelDavid Spencer
3rd Year PhD Student
Nuclear Department
Area of Concern
Submarine PWR Primary Circuit
• Austenitic Stainless Steel – 304L
• Chloride Ions – Cl-
• Tensile Stress – Applied or Residual
Crack Propagation
Crack propagating along metallic grain boundaries
Metallic Grains
Grains
Crack propagating across grains
Transgranular
Intergranular
Initial Development• Previous finite element study had shown that
anomalous crack propagation occurred at prior plastic strains of around 5%
• New atmospheric test developed to emulate chloride contamination on the exterior of primary circuit
• Conditions under which severe transgranular SCC occurred established
• Full factorial study planned to distinguish between the interacting factors controlling crack propagation rates.
Bent Beam Test
Test Configuration
2.5 Days 180MPa 3% Strain
Initiation at Pitting
Shallow Crack Propagation
Typical Crack Front
Crack tip propagating to within 0.2mm of the far side of the specimen
Factorial Investigation
Inputs Levels
Stress 60 MPa 120MPa
Strain 0% 0.5% 1% 2% 5%
Temp 60ºC 75ºC 90ºC
Humidity 30% 70%
FIB Milled Section of Crack Tip
Any Questions?
thanks to:
Dr Ian Giles
Dr Paul Chard-Tuckey
Dr Mike Edwards
Corrosion Enhanced Plasticity Model
The corrosion enhanced plasticity model Magnin et al.(1996)