Menu
Search
Filters
Close
Menu

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

Stress Corrosion Cracking (SCC) and Electrochemical Corrosion Study of Cold Formed Alloy 625 (UNS N06625) In Extremely Low pH and High Chloride Conditions

Picture for Stress Corrosion Cracking (SCC) and Electrochemical Corrosion Study of Cold Formed Alloy 625 (UNS N06625) In Extremely Low pH and High Chloride Conditions
Available for download

Alloy 625 (UNS N06625) is an austenitic solid solution strengthened nickel-chromium-molybdenum alloy containing niobium. The high alloy content of alloy 625 enables it to withstand a wide variety of severe corrosive environments. In mild environments, such as ambient atmosphere, fresh and seawater, neutral salts and alkaline media, there is almost no attack.

Product Number: 51322-17782-SG
Author: Suresh Divi, Sri Krishna Chimbli
Publication Date: 2022
Industries: Corrosion Monitoring and Control , Coatings and Linings , Coatings
$0.00
$20.00
$20.00

Corrosion-resistant alloy (CRA) such as alloy 625 (UNS N06625) provides excellent corrosion resistance and chloride stress-corrosion cracking (SCC) resistance than stainless steels in many corrosive environments. Literature shows that under annealed condition alloy 625 is immune to chloride stress-corrosion cracking in high chloride environments and provide excellent localized corrosion resistance in high chloride concentrations. However, the literature shows that when the alloy is heavily cold formed it could become more sensitive to high chloride levels and susceptible to SCC.

In order to understand the sensitivity of alloy 625 under cold-worked conditions, SCC tests were performed on annealed and cold-formed alloy 625 in boiling high concentrations (50,000 ppm and 80,000 ppm) of chlorides (NaCl) and at very low pH (1.0). Electrochemical, linear polarization resistance (LPR) and cyclic potentiodynamic polarization (CPP) scans at 40oC were also performed to study the corrosion and passivation behavior under the above-mentioned chloride concentrations.

The test results show that under cold-formed conditions alloy 625 is not susceptible to SCC in very high concentrations (50,000 ppm and 80,000 ppm) of chlorides and under low pH (1.0) conditions and CPP scans at 40oC demonstrates that under cold-formed condition, the alloy 625 is not susceptible to pitting corrosion.

Corrosion-resistant alloy (CRA) such as alloy 625 (UNS N06625) provides excellent corrosion resistance and chloride stress-corrosion cracking (SCC) resistance than stainless steels in many corrosive environments. Literature shows that under annealed condition alloy 625 is immune to chloride stress-corrosion cracking in high chloride environments and provide excellent localized corrosion resistance in high chloride concentrations. However, the literature shows that when the alloy is heavily cold formed it could become more sensitive to high chloride levels and susceptible to SCC.

In order to understand the sensitivity of alloy 625 under cold-worked conditions, SCC tests were performed on annealed and cold-formed alloy 625 in boiling high concentrations (50,000 ppm and 80,000 ppm) of chlorides (NaCl) and at very low pH (1.0). Electrochemical, linear polarization resistance (LPR) and cyclic potentiodynamic polarization (CPP) scans at 40oC were also performed to study the corrosion and passivation behavior under the above-mentioned chloride concentrations.

The test results show that under cold-formed conditions alloy 625 is not susceptible to SCC in very high concentrations (50,000 ppm and 80,000 ppm) of chlorides and under low pH (1.0) conditions and CPP scans at 40oC demonstrates that under cold-formed condition, the alloy 625 is not susceptible to pitting corrosion.

Product tags
Also Purchased
Picture for Study On Elemental Sulfur Formation From Black Powder Deposits
Available for download

Study On Elemental Sulfur Formation From Black Powder Deposits

Product Number: 51322-17678-SG
Author: Yousef Khuraibut
Publication Date: 2022
$20.00

Black Powder is a phenomenon that all oil and gas companies are facing and presenting a variety of problems in associated processing equipment and pipelines, such as flow inefficiency, product contamination, wear, plugging and under deposit corrosion, among others. Another major concern is the possible formation of elemental Sulfur (S8), which could be produced as a by-product of oxidation of iron sulfides. It also can be produced from H2S dissociation at elevated temperatures or by microbiological reactions, involving the reduction of sulfate.
Stress Relaxation Cracking Of Thin Alloy 800/800H Electric Heater Tubular Heating Elements
Available for download

Stress Relaxation Cracking Of Thin Alloy 800/800H Electric Heater Tubular Heating Elements

Product Number: 51322-17921-SG
Author: Iyad Al-Buraiki, Mohammed Abu Alsaud, Sadiq Al-Ismail
Publication Date: 2022
$20.00

Stress relaxation cracking (SRC) is a failure mechanism known to occur in austenitic stainless steels and nickel alloys operating at moderate to high temperatures.   

Typically, SRC failures tend to occur under the following conditions: 1-6  1. Susceptible material: 800H, 347H, 617, etc. (typically materials with low creep ductility)  2. High residual stresses: Hardness > 200 HV (welded thick section) 3. Specific temperature range: usually between 500 °C (932 °F) and 750 °C (1382 °F). 

Under these conditions, component stresses are relieved by time dependent inelastic deformation.3 In susceptible materials, this process occurs by intergranular cracking and is essentially a creep mechanism.2-6 In this respect, materials with low creep ductility tend to be prone to this type of damage mechanism. On the other hand, materials that have good creep ductility can tolerate the inelastic strains due to relaxation without cracking.3 
Picture for Storage Well Cathodic Protection Comparative Assessment
Available for download

Storage Well Cathodic Protection Comparative Assessment

Product Number: 51322-17647-SG
Author: Daniel Fingas, Jean-Patrick Boudreault, Bradley Jefferies
Publication Date: 2022
$20.00

When two long-time operators of natural gas storage wells in southwestern Ontario merged, it was an opportune time for the combined company to evaluate the effectiveness and impact of cathodic protection (CP). Staff from both legacy operators expressed general satisfaction with the longevity of their storage wells, typically 30+ years, but they had relied on two different approaches to corrosion control: one had isolated wells from flowlines and operated without CP, while the second had resistively bonded wells to cathodically protected flowlines. For the second operator, typical well currents were in the range of ~3 A.
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