scholarly journals The Importance of Local Chemistry and Potential in Localized Corrosion and Stress-Corrosion Cracking

CORROSION ◽  
10.5006/4019 ◽  
2021 ◽  
Author(s):  
Robert Kelly
Keyword(s):  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Intergranular Corrosion ◽  
Crevice Corrosion ◽  
Scaling Laws ◽  
Salt Spray ◽  
Water Layer ◽  
Lap Joints ◽  
Corrosion Cracking ◽  
Localized Corrosion

The nature and rates of the chemical and electrochemical reactions that occur within the occluded regions of a given alloy are controlled by the local electrochemical potential and the local solution composition. The very small physical dimensions of these regions lead to challenges in both measurement and modeling. When performed in a coordinated and complementary way, measurements and modeling provide insights into the controlling processes of a range of localized corrosion phenomena, including crevice corrosion, pitting, intergranular corrosion, and stress-corrosion cracking. Examples of attempts to overcome the measurement challenges are described for a range of corrosion scenarios, including identification of the critical ionic species in stainless steel crevice corrosion and in the corrosion of aircraft lap joints, operando measurement of chemistry and potential simultaneously within stress-corrosion cracks, and monitoring of water layer thickness in salt spray testing. Examples of work addressing the challenges in modeling localized corrosion including intergranular corrosion of AA5XXX alloys, scaling laws in crevice corrosion, the extent to which the Laplace Equation can be used and applied to geometrically complex galvanic structures, and an approach to modeling localized corrosion for extraordinarily long service times. Finally, suggestions regarding future avenues of research are provided.

Concept of the Occluded Corrosion Cell

CORROSION ◽  
1970 ◽  
Vol 26 (8) ◽  
pp. 349-350 ◽  
Author(s):  
B. F. BROWN
Keyword(s):  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Intergranular Corrosion ◽  
Crevice Corrosion ◽  
Corrosion Cracking ◽  
The Self ◽  
Corrosion Cell ◽  
Filiform Corrosion ◽  
Corrosion Pitting ◽  
The Common

Abstract It is proposed that the various localized forms of corrosion (pitting, stress corrosion cracking, intergranular corrosion, crevice corrosion, filiform corrosion, tuberculation, and exfoliation) have the common feature of local acidification by hydrolysis. The acidity is viewed as having a responsible role in the self-perpetuating character of these corrosion forms. Three possible benefits of this rationale are offered.

NICROFER 5716 HMoW

Alloy Digest ◽  
1985 ◽  
Vol 34 (11) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Stress Corrosion ◽  
Tensile Properties ◽  
Stress Corrosion Cracking ◽  
Crevice Corrosion ◽  
Corrosion Cracking ◽  
Low Carbon ◽  
Nickel Chromium ◽  
Corrosion Pitting

Abstract NICROFER 5716 HMoW is a nickel-chromium-molybdenum alloy with tungsten and extremely low carbon and silicon contents. It has excellent resistance to crevice corrosion, pitting and stress-corrosion cracking. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, machining, and joining. Filing Code: Ni-324. Producer or source: Vereingte Deutsche Metallwerke AG.

scholarly journals A Review on the Applications of Acoustic Emission Technique in the Study of Stress Corrosion Cracking

2020 ◽  
Vol 2 (1) ◽  
pp. 1-33
Author(s):  
Luigi Calabrese ◽  
Edoardo Proverbio
Keyword(s):  
Acoustic Emission ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Future Trend ◽  
Corrosion Cracking ◽  
In Situ Monitoring ◽  
Localized Corrosion ◽  
Complex Nature ◽  
Damage Propagation ◽  
Research Activities

The complex nature of the damage evolution in stress corrosion cracking (SCC) leads to explore for new investigation technologies in order to better identify the mechanisms that supervise the initiation and evolution of the damage as well to provide an improvement of knowledge on this critical localized corrosion form during time. Research activities concerning the use of acoustic emission (AE) technique to assess SCC has acquiring considerably relevance in recent decades. The non-invasiveness and the possibility to provide a continuous in situ monitoring of structures and components make this non-destructive technique clearly promising in the field of structural health monitoring. In this concern, this paper aims to be a focused overview on the evaluation of SCC phenomena by AE technique. The main topic of this review is centered on the approaches that can be used in elaborating AE data to better discriminate the mechanisms that contribute to damage propagation in SCC conditions. Based on available literature, investigation approaches assessing AE waveform parameters were classified, evidencing, furthermore, the identified mechanisms that synergistically take place during the material degradation. Eventually, a brief summary and a future trend evaluation was also reported.

scholarly journals Intergranular Corrosion and Stress Corrosion Cracking of Cold-Rolled Zircaloy-2.

1994 ◽  
Vol 43 (488) ◽  
pp. 551-555
Author(s):  
Hitoshi UCHIDA ◽  
Shozo INOUE ◽  
Kazuyuki MORIMOTO ◽  
Keiji KOTERAZAWA
Keyword(s):  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Intergranular Corrosion ◽  
Corrosion Cracking ◽  
Cold Rolled

Use of Accelerated Intergranular Corrosion Tests and Pitting Corrosion Tests to Detect Sensitization and Susceptibility to Intergranular Stress Corrosion Cracking in High Temperature Water of Duplex 308 Stainless Steel

CORROSION ◽  
1981 ◽  
Vol 37 (2) ◽  
pp. 104-115 ◽  
Author(s):  
T. M. Devine ◽  
B. J. Drummond
Keyword(s):  
Stainless Steel ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Pitting Corrosion ◽  
Intergranular Corrosion ◽  
Corrosion Cracking ◽  
Intergranular Stress Corrosion ◽  
Corrosion Tests ◽  
Duplex Alloy ◽  
Intergranular Stress Corrosion Cracking

Abstract The ability of various intergranular corrosion and pitting corrosion tests to detect sensitization and intergranular stress corrosion cracking susceptibility in high temperature water of duplex 308 stainless steel was evaluated. The duplex alloy contained 10 v/o ferrite and had a specific austenite-ferrite interfacial area of 930 cm2/cm3. The intergranular corrosion resistance of the alloy following 30 different aging treatments was determined in boiling acidified CU-CUSO4 solution (A262E), boiling 65% HNO3 (A262C), and by an electrolytic etch test in 10% oxalic acid (A262A). The pitting corrosion resistance was evaluated by potentiodynamic and galvanostatic tests in 0.1 N HCl at room temperature. The results of all five tests were compared to the results of slow extension rate stress corrosion cracking tests conducted at 550 F in high purity water containing 8 ppm dissolved oxygen. The microstructural features responsible for the corrosion in each test were determined. The A262E test was found to attack the chromium depleted zones in the material. The A262C test preferentially corroded the chromium depleted zones but also dissolved, albeit to a much less extent, the chromium rich phases such as M23C6. The A262A test primarily attacked chromium rich phases. Pitting corrosion was confined to the chromium depleted zones. The results of the A262E test and the galvanostatic pitting test agreed quite closely with the results of the stress corrosion cracking test. There was considerable scatter in the weight loss measurements obtained in the A262C test. The latter could detect the presence of a severely sensitized microstructure but was incapable of distinguishing between mildly sensitized and unsensitized materials. Although pitting was largely confined to the chromium depleted boundaries, unless the sample was severely sensitized, there was considerable scatter in the measured values of the pitting potential. This precluded the use of the latter as a parameter to characterize the degree of sensitization. The A262A test results exhibited the least correlation with the results of the stress corrosion cracking tests. Since the A262A test attacks chromium rich phases such as M23C6, samples which were aged long enough to intergranularly precipitate M23C6 but not long enough to produce chromium depleted zones of sufficient width or contiguity, nevertheless were severely corroded in the A262A test. And samples which were aged long enough to replenish the chromium depleted zones still failed the A262A test because of the continued presence of the chromium rich grain boundary carbides. These tests were also conducted on samples of sensitized and unsensitized austenitic 308 stainless steel. The results were consistent with the findings of the duplex alloy tests.

Effect of Long-Term Service Exposure on the Localized Corrosion and Stress Corrosion Cracking Susceptibility of Type 347 Stainless Steel

CORROSION ◽  
10.5006/2612 ◽  
2017 ◽  
Vol 74 (3) ◽  
pp. 350-361 ◽  
Author(s):  
K. Ravindranath ◽  
N. Tanoli ◽  
B. Al-Wakaa
Keyword(s):  
Stainless Steel ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking ◽  
Localized Corrosion ◽  
X Ray Diffraction ◽  
Degree Of Sensitization ◽  
Corrosion Susceptibility ◽  
Service Exposure

The paper presents the results of a study conducted on the effects of long-term service exposure of Type 347 stainless steel (SS) on the microstructure and corrosion susceptibility. The material subjected to the study was in service in a petroleum refinery as heater tube at 620°C for 31 years. The microscopic and x-ray diffraction studies of the service-exposed specimen revealed the precipitation of chromium-rich carbides along the grain boundaries. The microstructural changes that occurred as a result of service exposure affected the ductility and toughness of the alloy. The sensitization of the alloy was assessed by scanning electron microscopy and double loop electrochemical potentiodynamic reactivation. The studies have indicated some degree of sensitization in the alloy. The service exposure resulted in a marginal increase in the susceptibility of Type 347 SS to pitting in environments containing NaCl and NaCl + H2S. Environments such as H2SO4 and K2S4O6 at the tested concentrations did not differentiate between service-exposed and solution annealed specimens for their corrosion susceptibility. Slow strain rate testing of Type 347 SS in both the service-exposed and solution annealed conditions showed susceptibility to stress corrosion cracking in environment containing NaCl + H2S, while the alloy did not show susceptibility to SCC in H2SO4 and K2S4O6. The long-term service exposure did not noticeably influence the SCC susceptibility of Type 347 SS under the tested conditions.

Intergranular Corrosion and Stress Corrosion Cracking of Sensitised AA5182

2006 ◽  
Vol 519-521 ◽  
pp. 641-646 ◽  
Author(s):  
Alison J. Davenport ◽  
Yudie Yuan ◽  
Rajan Ambat ◽  
Brian J. Connolly ◽  
Martin Strangwood ◽  
...  
Keyword(s):  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Intergranular Corrosion ◽  
Corrosion Cracking ◽  
Critical Factors ◽  
Phase Precipitation ◽  
Β Phase ◽  
Grain Boundary Plane ◽  
Corrosion Susceptibility ◽  
Variable Precipitation

AA5182 (Al-4.5 wt% Mg) can become susceptible to intergranular corrosion (IGC) with time at moderately elevated service temperatures owing to precipitation of Mg-rich β-phase at grain boundaries, which can lead to stress corrosion cracking (SCC). The IGC and SCC susceptibility of AA5182 was found to depend strongly on sensitisation heat treatments. AFM and TEM studies demonstrated that the degree of precipitation and thus susceptibility to attack for a boundary can be related to its crystallographic misorientation. Low angle boundaries (<20°) are most resistant to attack as they do not show β-phase precipitation. However, higher angle boundaries show highly variable precipitation and corrosion susceptibility: critical factors are the grain boundary plane and precipitate/matrix crystallographic relationship.

Sign in / Sign up

Export Citation Format

Share Document