External Stress Corrosion Cracking Research Articles

Analysis of the Physicochemical, Mechanical, and Electrochemical Parameters and Their Impact on the Internal and External SCC of Carbon Steel Pipelines.

The review presented herein is regarding the stress corrosion cracking (SCC) phenomena of carbon steel pipelines affected by the corrosive electrolytes that comes from external (E) and internal (I) environments, as well as the susceptibility and tensile stress on the SCC. Some useful tools are presented including essential aspects for determining and describing the E-SCC and I-SCC in oil and gas pipelines. Therefore, this study aims to present a comprehensive and critical review of a brief experimental summary, and a comparison of physicochemical, mechanical, and electrochemical data affecting external and internal SCC in carbon steel pipelines exposed to corrosive media have been conducted. The SCC, hydrogen-induced cracking (HIC), hydrogen embrittlement, and sulfide stress cracking (SSC) are attributed to the pH, and to hydrogen becoming more corrosive by combining external and internal sources promoting cracking, such as sulfide compounds, acidic soils, acidic atmospheric compounds, hydrochloric acid, sulfuric acid, sodium hydroxide, organic acids (acetic acid, mainly), bacteria induced corrosion, cathodic polarization, among others. SCC growth is a reaction between the microstructural, chemical, and mechanical effects and it depends on the external and internal environmental sources promoting unpredictable cracks and fractures. In some cases, E-SCC could be initiated by hydrogen that comes from the over-voltage during the cathodic protection processes. I-SCC could be activated by over-operating pressure and temperature at flowing media during the production, gathering, storage and transportation of wet hydrocarbons through pipelines. The mechanical properties related to I-SCC were higher in comparison with those reviewed by E-SCC, suggesting that pipelines suffer more susceptibility to I-SCC. When a pipeline is designed, the internal fluid being transported (changes of environments) and the external environment concerning SCC should be considered. This review offers a good starting point for newcomers into the field, it is written as a tutorial, and covers a large number of basic standards in the area.

External Stress Corrosion Cracking Risk Factors of High Grade Pipeline Steel

The influence weights of various sensitive factors, such as steel grade, applied potential, temperature and soil environment, on stress corrosion cracking behavior of high-grade pipeline steel were studied by means of orthogonal test at mixed level and slow strain rate test. The stress corrosion behavior of X80 pipeline steel in near neutral and high pH simulated soil solution under overprotection potential was observed by SEM. The results showed that the applied potential has the greatest weight on stress corrosion index of ISSRT, followed by temperature, steel grade and soil environment. X80 pipeline steel exhibits high stress corrosion sensitivity in near-neutral and high pH simulated soil solutions at applied potential of -1500mV, and its SCC mechanism is hydrogen embrittlement (HE). This study can provide guidance for practical engineering application of pipeline steel.

外面応力腐食割れ(ESCC)の感受性の評価

There are three elements, namely environment, material, and stress, as susceptibility conditions of damage patterns of the equipment. Susceptibility of damage can be mainly evaluated by temperature parameter. Damage patterns of the equipment become apparent in low temperature region, normal temperature region and high temperature region along with aging degradation, and these damage patterns cause leakage during operation. In particular, damage appears prominently under low temperature environment. Among them, it is difficult to extract susceptibility to external stress corrosion cracking External stress corrosion cracking of austenitic stainless steel is generated when grain boundary Cr depletion layer (sensitization) of weld heat affected zone (HAZ) occurs due to rainwater retention and sea salt particles. However, sensitization does not occur in all of HAZ. Occurrence of sensitization differs in every part. Therefore, this paper describes in detail findings obtained from survey results on the ESCC in a chemical plant.

The Role of Calcareous Soils in SCC of X52 Pipeline Steel

ABSTRACTSusceptibility to external stress corrosion cracking (ESCC) of API X52 pipeline steel in calcareous soil containing different moisture content has been investigated using slow strain rate tests (SSRT). This type of soil is common of the state of Campeche Mexico and has a pH around 8. The results indicate that X52 pipeline steel was susceptible to external SCC only in the saturated calcareous soil, showing some micro cracks in the gage section of the SSR specimen. It was observed that some micro cracks were found at the bottom of micro-pits. Which indicate that first develop a pit and this evolved with time and micro-strain like a crack. Few micro cracks were observed as initiation of SCC close to surface failure. The mechanism of SCC may be influenced by formation and rupture film of carbonates.

Failure analysis of 316L stainless steel tubing of the high-pressure still condenser

Sherritt International Corporation experienced corrosion failures with the 316L stainless steel tubing in a high-pressure still condenser employed for ammonia recovery. A detailed failure analysis was conducted on the condenser tubing to determine the mode and the root cause of the failure. The analysis included both optical and scanning electron microscopy (SEM) of the inner and outer surfaces of the tube as well as characterization of the corrosion products using energy-dispersive X-ray spectroscopy (EDX). Results revealed that the corrosion attack was confined to the first ∼100 mm of the tubing at the inlet where the tube was connected to the top tubesheet. The tube suffered both external stress-corrosion cracking (SCC) and crevice corrosion from the shell side (water side), and wall thinning of the inner surface (the tube side) due to erosion corrosion. It was evident that failure of one of the tubes occurred due to SCC that penetrated the whole wall thickness and resulted in a leak failure. Some prevention measures are proposed to avoid this type of corrosion attack in the future.

Stress corrosion cracking of stainless-steel canister for concrete cask storage of spent fuel

Resistance to external stress corrosion cracking (ESCC) and crevice corrosion were examined for various candidate canister materials in the spent fuel dry storage condition using concrete casks. A constant load ESCC test was conducted on the candidate materials in air after deposition of simulated sea salt particles on the specimen gage section. Highly corrosion resistant stainless steels (SS), S31260 and S31254, did not fail for more than 46 000 h at 353 K with relative humidity of 35%, although the normal stainless steel, S30403 SS failed within 500 h by ESCC. Crevice corrosion potentials of S31260 and S31254 SS became larger than 0.9 V (SCE) in synthetic sea water at temperatures below 298 K, while those of S30403 and S31603 SS were less than 0 V (SCE) at the same temperature range. No rust was found on S31260 and S31254 SS specimens at temperatures below 298 K in the atmospheric corrosion test, which is consistent with the temperature dependency of crevice corrosion potential. From the test result, the critical temperature of atmospheric corrosion was estimated to be 293 K for both S31260 and S31254 SS. Utilizing the ESCC test result and the critical temperature, together with the weather station data and the estimated canister wall temperature, the integrity of canister was assessed from the view point of ESCC.

SUS304 ステンレス鋼の大気中塩化物応力腐食割れに及ぼす負荷応力の影響

Austenitic stainless steels (SS) are widely used in various components of chemical plants, nuclear power plants, etc, because of the superior mechanical property and general corrosion resistance. However, it is also well known that austenitic stainless steels are susceptible to localized corrosion in the environments containing chloride ions, and several equipment in the plants built in coastal area has been suffering from chloride induced external stress corrosion cracking (ESCC). Hence, for the establishment of the countermeasures it is very important to clarify the factors governing ESCC process from the view points of stress, material and environmental conditions. The purpose of this study is to investigate the effect of applied stress on ESCC of type 304 stainless steel. ESCC tests were conducted on type 304 SS specimens, which were fabricated from a cold rolled plate, by a uniaxial constant load method using springs. After loading, droplets of synthetic sea water were put on the gage section of specimen and dried, and then the specimens were placed in a chamber with a constant temperature of 353 K and a relative humidity of 35%. The test specimens after the test were observed by a scanning electron microscope to measure the crack length and depth. No clear difference was found in the maximum values of the average crack propagation rate (crack depth divided by test time) among the applied stress conditions. In addition, most of ESCC were initiated from the bottom or periphery of pits under the low applied stress condition (0.5σ0.2).

アコースティック・エミッション (AE) を用いた外面応力腐食割れ (ESCC) の検出

アコースティック・エミッション (AE) を用いた外面応力腐食割れ (ESCC) の検出

ステンレスの外面応力腐食割れ(ESCC)のAEモニタリング(発電プラントにおける非破壊検査と保守,発電プラントにおける非破壊検査と保守)

ステンレスの外面応力腐食割れ(ESCC)のAEモニタリング(発電プラントにおける非破壊検査と保守,発電プラントにおける非破壊検査と保守)

Finite-Element Analysis for Remote Field Eddy Current Responses from Near- and Farside Cracks

Results of three-dimensional finite-element analysis investigations of remote field eddy current (RFEC) signal responses from internal and external stress corrosion cracking (SCC) in steel pipes are presented. The fine shallow SCC cracks were simulated by double axial slits located on the near- and farside pipe surfaces under simulated RFEC excitation. Although it is normally a characteristic of RFEC testing that responses to interior or exterior defects are approximately equal, there is a considerable difference between the farside and nearside responses from very fine defects such as SCC cracks.

Finite-Element Analysis for Remote Field Eddy Current Responses from Near- and Farside Cracks

Results of three-dimensional finite-element analysis investigations of remote field eddy current (RFEC) signal responses from internal and external stress corrosion cracking (SCC) in steel pipes are presented. The fine shallow SCC cracks were simulated by double axial slits located on the near- and farside pipe surfaces under simulated RFEC excitation. Although it is normally a characteristic of RFEC testing that responses to interior or exterior defects are approximately equal, there is a considerable difference between the farside and nearside responses from very fine defects such as SCC cracks.

ステンレス鋼の外面応力腐食割れ

ステンレス鋼の外面応力腐食割れ

オーステナイト系ステンレス鋼の外面応力腐食割れに関する実態調査

オーステナイト系ステンレス鋼の外面応力腐食割れに関する実態調査

ステンレス鋼の常温大気中応力腐食割れに関する暴露試験結果と実験室的検討

ステンレス鋼の常温大気中応力腐食割れに関する暴露試験結果と実験室的検討

正誤表

正誤表

ラインパイプ用鋼の応力腐食割れ感受性に及ぼす材料因子の影響

ラインパイプ用鋼の応力腐食割れ感受性に及ぼす材料因子の影響

ラインパイプ用鋼の応力腐食割れ感受性に及ぼす環境因子の影響

ラインパイプ用鋼の応力腐食割れ感受性に及ぼす環境因子の影響

保温断熱材による応力腐食割れ

保温断熱材による応力腐食割れ