Sulfide Stress Corrosion Cracking in Welded Joints of Welded Linepipes.

Endo, Shigeru; Nagae, Moriyasu; Kobayashi, Yasuo; Ume, K.

doi:10.2355/isijinternational.34.217

Cited by 15 publications

(9 citation statements)

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“…1,2,10-15 The ICHAZ is characterised by heating between Ac 1 -Ac 3 transformation temperature (azc region) by the thermal cycles of welding, enhancing the formation of martensite-austenite microconstituents and for the minimum hardness (low yield strength). According to the results of Taira, 5 Endo, 10 Kobayashi 11 and Nippon Kokan, 15 the yield strength of the ICHAZ decreases 10% of the original yield strength, and in addition, the s th /s y ratios for the welds are usually smaller by y10% of the yield strength of the BM. That is, this decrease in strength allows microscopically the ICHAZ to be deformed plastically to the larger extent, which may lead to a high possibility of developing SSC in the ICHAZ.…”

Section: Fracture Behaviourmentioning

confidence: 98%

Sulphide stress corrosion cracking of multiple welding repairs of girth welds in line pipe

Vega

Villagomez²,

Hallen

et al. 2009

Corrosion Engineering, Science and Technology

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The susceptibility to sulphide stress corrosion cracking (SSCC) of four conditions of shielded metal arc welding repairs and one as welded specimen of the girth weld in seamless API X-52 microalloyed steel pipe were evaluated using slow strain rate tests. The slow strain rate tests were performed in air and in a NACE solution saturated with H 2 S both at room temperature to a constant elongation rate of 25?4610 26 mm s 21 . The SSCC susceptibility was evaluated in function of the reduction in area ratio and elongation ratio and also was manifested as a decrease in the mechanical properties. According to this consideration it is clear that all the weldments exhibit a great susceptibility to SSCC. After failure, the fracture surfaces were observed in the scanning electron microscope. The metallographic observations of the fractured specimens showed that the most susceptible area to SSCC was the intercritical heat affected zone.

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Section: Fracture Behaviourmentioning

confidence: 98%

Sulphide stress corrosion cracking of multiple welding repairs of girth welds in line pipe

Vega

Villagomez²,

Hallen

et al. 2009

Corrosion Engineering, Science and Technology

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show abstract

“…[3][4][5] During pipeline operation, tensile stress is applied in the circumferential direction of the inner surface of the pipe, and in the sour environment, there is a fear of a fracture accident due to SSC. Since the SSC is mainly affected by three factors: material, [6][7][8] sour environment, 9,10) and applied stress, 11,12) the material has a hardness limit as shown in the NACE MR 0175/ISO 15156-1 standard, and a hardness upper limit of 22 HRC (about 250 HV10) is specified…”

Section: Introductionmentioning

confidence: 99%

Sulfide Stress Cracking (SSC) of Low Alloy Linepipe Steels in Low H<sub>2</sub>S Content Sour Environment

Shimamura¹,

Morikawa

Yamasaki

et al. 2022

ISIJ Int.

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Resistance to Sulfide Stress Cracking (SSC) caused by local hard zones of pipe inner surface has been required in low alloy linepipe steel. In this study, using two samples with different surface hardness, the detailed SSC initiation behavior was clarified by four-point bend (4PB) SSC tests in which immersion time and applied stress were changed in a sour environment containing 0.15 bar hydrogen sulfide (H 2 S) gas. SSC cracks occurred when the applied stress was higher than 90% actual yield strength (AYS) in higher surface hardness samples over 270 HV0.1. From the fracture surface observation of SSC crack sample, it was found that the mechanism gradually shifted from active path corrosion (APC) to hydrogen embrittlement (HE), and that the influence of APC mechanism remained partially in the process of SSC initiation at the tip of corrosion pit or groove. The polarization measurement in the 4PB SSC test showed that the anodic and cathodic reactions (especially cathodic reactions) were activated when the applied stress was 90% AYS or higher. The FEM coupled analysis simulating the stress and strain concentration at the bottom tip of the corrosion groove and the hydrogen diffusion and accumulation was carried out. The principal stress in the tensile direction showed the maximum value at 0.04-0.06 mm away from the tip of the corrosion groove, and the hydrogen accumulation became the maximum. It was analytically found that the SSC crack initiated and propagated with HE mechanism dominated type when the threshold value of about 0.82 ppm is exceeded.

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“…6) In the 1980s, measures against SSC were taken in linepipes made from thick steel plates by the thermo-mechanical controlled process (TMCP) utilizing controlled rolling and controlled cooling. 5) Since that time, many studies have been carried out, and it is known that SSC is mainly affected by the three factors of material, [7][8][9] sour environment, 10,11) and applied stress. 12,13) In order to avoid SSC, a hardness limit is applied to the material in the design of sour linepipes,…”

Section: Introductionmentioning

confidence: 99%

Effect of Surface Hardness and Hydrogen Sulfide Partial Pressure on Sulfide Stress Cracking Behavior in Low Alloy Linepipe Steel

SHIMAMURA¹,

Izumi²,

SAMUSAWA³

et al. 2022

ISIJ Int.

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TMCP (thermo-mechanical controlled process) linepipes have long been used in severe sour environments, but recently sulfide stress cracking (SSC) caused by local hard zones has become a concern. In order to clarify the hardness threshold that leads to SSC, four-point bend (4PB) SSC tests as specified in NACE TM0316 were conducted under several H 2 S partial pressure conditions. At H 2 S partial pressures of 1 bar and higher, the surface hardness threshold (at 0.25 mm from the surface) observed in 4PB SSC specimens without SSC cracking was approximately correlated to a maximum acceptable hardness level of 250 HV0.1. A stable low surface hardness of 250 or less HV0.1 was achieved by suppressing hard lath bainite (LB) and obtaining a soft granular bainite (GB) microstructure, resulting in a superior SSC-resistant property. It was found that a SSC crack propagated when the surface hardness increased due to an increasing volume fraction of the LB microstructure. Under a 16 bar H 2 S partial pressure condition, the crack growth rate increased in the sour environment, and hydrogen embrittlement by H 2 S was promoted. However, in the 4PB SSC test at 16 bar, the stress concentration and the transition to a crack were suppressed because the shape of localized corrosion was semicircular due to low localized corrosivity. This can be the reason why the SSC susceptibility was similar to 1 bar condition, especially in the 4PB SSC test using the samples with lower surface hardness level of 250 or less HV0.1.

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Sulfide Stress Corrosion Cracking in Welded Joints of Welded Linepipes.

Abstract: The sulfide stress cracking (SSC) behavior of

Cited by 15 publications

References 0 publications

Sulphide stress corrosion cracking of multiple welding repairs of girth welds in line pipe

Sulphide stress corrosion cracking of multiple welding repairs of girth welds in line pipe

Sulfide Stress Cracking (SSC) of Low Alloy Linepipe Steels in Low H<sub>2</sub>S Content Sour Environment

Effect of Surface Hardness and Hydrogen Sulfide Partial Pressure on Sulfide Stress Cracking Behavior in Low Alloy Linepipe Steel

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