Menu
Search
Filters
Close
Menu

Celebrate World Corrosion Awareness Day with 20% off eCourses and eBooks with code WCAD2024 at checkout!

Optimization of the DL-EPR Method for Detecting Sensitization in Alloy 690

Picture for Optimization of the DL-EPR Method for Detecting Sensitization in Alloy 690
Available for download

UNS N06690 is one of the current choices for nuclear power plant steam generator tubing. The objective of this work was the optimization of the double loop electrochemical potentiokinetic reactivation (DL-EPR) method for that alloy. Specimens were tested under different heat treatments.

Product Number: 51317--9037-SG
ISBN: 9037 2017 CP
Author: Mariano Kappes
Publication Date: 2017
Industries: Energy Generation , Science of Corrosion
$0.00
$20.00
$20.00

Alloy 690 is one of the current choices for nuclear power plant steam generator tubing. However several submodes of stress corrosion cracking have been identified for this alloy in the laboratory which eventually could manifest as failures in service. The intensity of some stress corrosion cracking (SCC) submodes in particular SCC in the presence of reduced sulfur species increases with sensitization. Sensitization is produced in some alloys after exposure to temperatures in the order of 500 to 800°C when chromium carbides precipitate at grain boundaries causing a local depletion of chromium in the surrounding zone. Some process used in steam generator fabrication like welding and stress relief treatment can result in sensitization of grain boundaries. Sensitization can be detected electrochemically as has been accomplished for austenitic stainless steels with the double loop electrochemical potentiokinetic reactivation (DL-EPR) method.The objective of this work was the optimization of the DL-EPR method for alloy 690. Alloy 690 samples were evaluated under different heat treatments tailored to obtain different concentrations of chromium in solid solution at the grain boundary region. DL-EPR was performed in solutions with different concentrations of sulfuric acid and potassium thiocyanate at 30 and 50ºC. Results were analyzed to conclude which solution can best correlate with the 690 alloy grain boundary condition.

Key words: UNS N06690, sensitization, intergranular corrosion, DL-EPR, steam generator

Alloy 690 is one of the current choices for nuclear power plant steam generator tubing. However several submodes of stress corrosion cracking have been identified for this alloy in the laboratory which eventually could manifest as failures in service. The intensity of some stress corrosion cracking (SCC) submodes in particular SCC in the presence of reduced sulfur species increases with sensitization. Sensitization is produced in some alloys after exposure to temperatures in the order of 500 to 800°C when chromium carbides precipitate at grain boundaries causing a local depletion of chromium in the surrounding zone. Some process used in steam generator fabrication like welding and stress relief treatment can result in sensitization of grain boundaries. Sensitization can be detected electrochemically as has been accomplished for austenitic stainless steels with the double loop electrochemical potentiokinetic reactivation (DL-EPR) method.The objective of this work was the optimization of the DL-EPR method for alloy 690. Alloy 690 samples were evaluated under different heat treatments tailored to obtain different concentrations of chromium in solid solution at the grain boundary region. DL-EPR was performed in solutions with different concentrations of sulfuric acid and potassium thiocyanate at 30 and 50ºC. Results were analyzed to conclude which solution can best correlate with the 690 alloy grain boundary condition.

Key words: UNS N06690, sensitization, intergranular corrosion, DL-EPR, steam generator

Product tags
Also Purchased
intergranular, stress corrosion cracking, crack initiation, UNS N06690, cold work, creep cavities, grain boundary microstructure
Available for download

Precursor Evolution and SCC Initiation of Cold-Worked Alloy 690 in Simulated PWR Primary Water

Product Number: 51317--9475-SG
ISBN: 9475 2017 CP
Author: Ziqing Zhai
Publication Date: 2017
$20.00

Stress corrosion crack initiation of two thermally-treated, cold-worked UNS N06690 materials was investigated in 360 ºC simulated primary water using constant load tensile tests and blunt notch compact tension tests equipped with direct current potential drop for in-situ detection of cracking.
Picture for Materials Selection Challenges for Geothermal Energy Projects
Available for download

Materials Selection Challenges for Geothermal Energy Projects

Product Number: 51317--9258-SG
ISBN: 9258 2017 CP
Author: Keith Lichti
Publication Date: 2017
$20.00

This paper describes some of the materials and process challenges facing geothermal energy developers targeting efficiency improvements and extremes of aggressive geothermal fluid chemistries and temperatures.

 
Picture for Optimization of Side-Groove Configuration On DCB Test
Available for download

Optimization of Side-Groove Configuration On DCB Test

Product Number: 51317--9102-SG
ISBN: 9102 2017 CP
Author: Jun Nakamura
Publication Date: 2017
$20.00

The Double Cantilever Beam test method in ANSI NACE TM0177 is increasingly applied as a QA test. In this analysis, influence of various side-groove root configurations (considered to change the stress concentration) on KISSC and Finite Element Analysis results were focused upon.
Categories
Industry
Recently viewed
Popular tags
View all

Association for Materials Protection and Performance

© AMPP All Rights Reserved.
Membership Terms of Content Use
Contact Customer Support