The Role of Hydrogen-Enhanced Strain-Induced Lattice Defects on Hydrogen Embrittlement Susceptibility of X80 Pipeline Steel

Hattori, Mitsuru; Suzuki, Hiroshi; Seko, Yusuke; Takai, Kenichi

doi:10.1007/s11837-017-2371-1

Cited by 22 publications

(8 citation statements)

References 14 publications

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“…This is referred to as the hydrogen-enhanced strain-induced vacancy (HESIV) model. [6][7][8] Intergranular, [9,10] quasi-cleavage [11][12][13] and shallow dimple [7,14] fracture modes have been reported as typical fracture surfaces related to HE. Intergranular and quasi-cleavage fracture modes have often been observed in high-strength martensitic steel.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen Desorption Spectra from Excess Vacancy-Type Defects Enhanced by Hydrogen in Tempered Martensitic Steel Showing Quasi-cleavage Fracture

Saito

Hirade

Takai

2019

Metall Mater Trans A

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An attempt was made to separate and identify hydrogen peaks desorbed from plastic-strained, hydrogen-enhanced lattice defects from among various trapping sites in tempered martensitic steel showing quasi-cleavage fracture using thermal desorption spectroscopy from a low temperature (L-TDS) and positron annihilation spectroscopy (PAS). The amount of the lattice defects beneath the quasi-cleavage fracture surface was measured by L-TDS. The L-TDS results made it possible to separate two peaks, namely that of the original desorption and also that of new desorption from the steel specimens due to the application of plastic strain in the presence of hydrogen. The PAS results revealed that the new desorption obtained by L-TDS corresponded to vacancy-type defects. Hydrogen and plastic strain noticeably enhanced lattice defects formed within 1.5 mm from the fracture surface, where the average concentration of vacancy-type defects reached approximately 10 À5 order in terms of atomic ratio. These results indicate that the accumulation of excess vacancy-type defects enhanced by hydrogen in the local region can lead to nanovoid nucleation and coalescence in plastic deformation, resulting in quasi-cleavage fracture of tempered martensitic steel.

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Section: Introductionmentioning

confidence: 99%

Hydrogen Desorption Spectra from Excess Vacancy-Type Defects Enhanced by Hydrogen in Tempered Martensitic Steel Showing Quasi-cleavage Fracture

Saito

Hirade

Takai

2019

Metall Mater Trans A

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“…Hence, at lower crosshead speeds, more hydrogen is trapped immediately by vacancies formed by the cutting of screw dislocations, etc., and stabilizes the vacancies. In fact, more hydrogen-enhanced strain-induced vacancies were formed with decreasing strain rates in X80 pipeline steel 32) and in cold-drawn pearlitic steel. 33,34) Since lattice defect formation showed strain rate dependence in these previous papers and in the present study, transgranular strength also shows strain rate dependence.…”

Section: Relationships Between Transition In Fracture Morphologies Anmentioning

confidence: 95%

Hydrogen Embrittlement Susceptibility Evaluation of Tempered Martensitic Steels Showing Different Fracture Surface Morphologies

et al. 2019

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The effects of the crosshead speed, hydrogen content and temperature on fracture strength and fracture surface morphology were investigated using a tempered martensitic steel containing 1.67 mass% of Si (H-Si) and one containing 0.21 mass% of Si (L-Si). When L-Si specimens were charged with a small amount of hydrogen, fracture surfaces showed a transition from quasi-cleavage (QC) to intergranular-like (IG-like) to intergranular (IG) at room temperature. In contrast, when H-Si specimens were charged with a small amount of hydrogen, fracture surfaces showed a transition from QC to IG-like at room temperature. This transition in the fracture surface morphology can be explained by the magnitude relationship between intergranular and transgranular strengths under hydrogen charging. At a temperature of − 196°C, hydrogen did not lower the fracture strength nor did it change the fracture surface morphology. Hence, hydrogen embrittlement at room temperature was presumably caused by hydrogen accumulation and lattice defect formation during stress application as well as by hydrogen trapped before stress was applied. Fracture strength decreased and converged to a constant value (lower critical stress) with decreasing crosshead speed. The crosshead speed for obtaining lower critical stress decreased as the fracture surface changed from IG to IG-like to QC. Therefore, the crosshead speed for obtaining lower critical stress should not be treated as a constant but should be determined experimentally for each type of fracture surface.

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“…properties. Slow strain rates are known to accentuate the loss of ductility [7], [53], [54]. ASTM G129 was consulted in determining an appropriate strain rate of 10 -4 /s for the embrittlement tensile tests.…”

Section: Tensile Testingmentioning

confidence: 99%

Microstructural evaluation of hydrogen embrittlement and successive recovery in advanced high strength steel

Allen

Nelson

2019

Journal of Materials Processing Technology

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Advanced high strength steels (AHSS) have high susceptibility to hydrogen embrittlement, and are often exposed to hydrogen environments in processing. In order to study the embrittlement and recovery of steel, tensile tests were conducted on two different types of AHSS over time after hydrogen charging. Concentration measurements and hydrogen microprinting were carried out at the same time steps to visualize the hydrogen behavior during recovery. The diffusible hydrogen concentration was found to decay exponentially, and equations were found for the two types of steel. Hydrogen concentration decay rates were calculated to be -0.355 /hr in TBF steel, and -0.225 /hr in DP. Hydrogen concentration thresholds for embrittlement were found to be 1.04 mL/100 g for TBF steel, and 0.87 mL/100g for DP steel. TBF steel is predicted to recover from embrittlement within 4.1 hours, compared to 7.2 hours in DP steel. A two-factor method of evaluating recovery from embrittlement, requiring hydrogen concentration threshold and decay rate, is explained for use in predicting recovery after exposure to hydrogen. Anisotropic hydrogen diffusion rates were also observed on the surface of both steels for a short time after charging, as hydrogen left the surface through <001> and <101> grains faster than grains with <111> orientations. This could be explained by differences in surface energies between the different orientations.

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The Role of Hydrogen-Enhanced Strain-Induced Lattice Defects on Hydrogen Embrittlement Susceptibility of X80 Pipeline Steel

Cited by 22 publications

References 14 publications

Hydrogen Desorption Spectra from Excess Vacancy-Type Defects Enhanced by Hydrogen in Tempered Martensitic Steel Showing Quasi-cleavage Fracture

Hydrogen Desorption Spectra from Excess Vacancy-Type Defects Enhanced by Hydrogen in Tempered Martensitic Steel Showing Quasi-cleavage Fracture

Hydrogen Embrittlement Susceptibility Evaluation of Tempered Martensitic Steels Showing Different Fracture Surface Morphologies

Microstructural evaluation of hydrogen embrittlement and successive recovery in advanced high strength steel

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