Role of microstructure and testing conditions in sulphide stress cracking of X52 and X60 API steels

Sojka, Jaroslav; Jérôme, M.; Sozańska, M.; Váňová, Petra; Rytířová, L.; Jonšta, Petr

doi:10.1016/j.msea.2007.07.029

Cited by 34 publications

(17 citation statements)

References 7 publications

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“…This type of hydrogen fracture has been observed in highly tempered 4130 steels, 12,33) in heat affected zones of low-carbon steel welds, 15) and in hardened low carbon steel subjected to slow strain rate tensile testing in a sulfide stress cracking environment. 34) Apparently the strong hydrogen trapping capacity of inclusions, often considered to be irreversible traps for hydrogen, 35) provides a source or reservoir for hydrogen that causes localized embrittlement, provided local stress concentrations, strain rate, and microstructure combine for embrittlement susceptibility. It should be noted that some brittle fracture zones due to hydrogen embrittlement were separated from other brittle fracture zones by localized regions of ductile failure, i.e.…”

Section: ϫ2mentioning

confidence: 99%

Hydrogen Embrittlement of Hardened Low-carbon Sheet Steel

et al. 2010

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Tensile specimens of 10B22 (22MnB5) sheet steels were austenitized, quenched to martensite, and tempered at temperatures between 150 and 520°C for various times. The heat treated specimens were charged with 1.7 ppm hydrogen and immediately tested. Fracture surfaces were examined by field emission scanning electron microscopy. As-quenched martensitic specimens exhibited the most severe embrittlement and failed by stress-controlled cleavage fracture at low stresses. The initiation of hydrogen-induced fracture in specimens tempered between 150 and 350°C was consistent with glide plane decohesion, and coarse inclusion particles served as sources of hydrogen for circular areas of hydrogen-induced cleavage. Specimens tempered at 460 and 520°C showed little sensitivity to hydrogen embrittlement. The progression of decreased sensitivity to hydrogen-induced fracture with increasing tempering temperature correlates with the reduction in dislocations, the principal hydrogen traps, and the formation of cementite particles, considered to be ineffectual traps, with increased tempering. Very small amounts of intergranular fracture were observed, only in as-quenched specimens, confirming that boron has little effect on hydrogen embrittlement of hardened low-carbon steels.KEY WORDS: hydrogen embrittlement; tempered martensite; low-carbon sheet steel; mechanical properties; SEM analysis; fracture mechanism.properties of quench and tempered specimens not exposed to hydrogen. 7,8) The specimens in the current study were tested immediately after hydrogen charging, and recent work by thermal desorption spectrometry on hydrogen trapping capability of quench and tempered low-carbon steels, 17,18) coupled with the results of mechanical testing and fractographic analysis of this investigation, provide useful information contributing to understanding hydrogen embrittlement of the heat treated 10B22 steel. Experimental ProcedureThe chemical composition of the low-carbon steel is given in Table 1. Boron is effectively used in low carbon steels to provide hardenability, and several studies have shown that boron additions in steel have little effect on hydrogen embrittlement. 19,20) Standard ASTM E-8 longitudinal tensile samples were machined from 1.7 mm thick commercially produced cold-rolled sheet steel. The tensile samples were austenitized at 900°C for 10 min in a salt bath and quenched in water. The quenched samples were tempered at temperatures between 150°C and 520°C for times of 600 s, 3 600 s, and 36 000 s in either oil or salt baths and air cooled after tempering.The tensile samples were cathodically charged with hydrogen with a DC power supply in a solution of 1 N H 2 SO 4 with 1 mg/L As 2 O 3 as a hydrogen recombination poison. 21)Charged coupons, 7ϫ7ϫ1.5 mm 3 , were used to determine induced hydrogen content in a LECO RH-404 hydrogen analyzer, and parameters were established to induce a constant hydrogen content of 1.7 ppm in all samples. A current density of 5 mA/cm 2 for 30 min was used for the asquenched samples and 10 mA/cm 2...

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Section: ϫ2mentioning

confidence: 99%

Hydrogen Embrittlement of Hardened Low-carbon Sheet Steel

et al. 2010

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“…7,8 In order to understand clearly HAC failure of the steels, the combined effect of hydrogen and applied stress should be evaluated together. A number of considerable efforts have been directed to evaluate the influence of applied tensile stress on the hydrogen diffusion behavior in the steel employing the electrochemical permeation technique.…”

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Determination of Hydrogen Diffusion Parameters of Ferritic Steel from Electrochemical Permeation Measurement under Tensile Loads

Kim

Yun

Jung

2014

J. Electrochem. Soc.

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The hydrogen permeation experiment, performed with a stepwise permeation sequence involving "1 st permeation-desorption-2 nd permeation under loading, demonstrates that fine blister cracks are frequently observed on the steel surface in hydrogen charging side after the 2 nd permeation under the load over 95% of yield strength of the steel. To accommodate the experimental phenomena under the loading conditions, a numerical model is developed for determination of hydrogen diffusion parameters of the sour-resistant ferritic steel evaluated under tensile stress in plastic ranges. To solve the modified diffusion equation, a numerical finite difference method (FDM) is employed. The diffusion parameters determined by curve-fitting with the newly proposed diffusion equation indicates that, with the transition of mechanical domain from local-plasticity to generalized-plasticity, a big increase in the crack formation rate and hydrogen capture rate per irreversible trap are observed. It suggests that the transition probability for hydrogen transport from interstitial lattice site to irreversible trap site increases with the stress level. The high-strength ferritic steels used in the petrochemical industry suffer frequently from hydrogen assisted cracking (HAC) problem when they are used in a sour environment containing H 2 S. 1-3 Atomic hydrogens which result from the reduction of H + ions dissociated from H 2 S become the hydrogen molecule by the recombination reaction (H + H → H 2 ). Since H 2 S dissolved in aqueous environment suppresses this recombination reaction, the hydrogen atoms are easily adsorbed on the steel surface and diffuse into the steel matrix.4,5 The hydrogen atoms absorbed in the steel are reversibly or irreversibly trapped at various metallurgical defects in the steel, often resulting in the HAC failure. 2,6 With the depletion of high quality oil and gas, the HAC failure may become serious engineering problem for the highstrength steel pipes transporting and/or processing the low quality oil and gas containing a large amount of H 2 S.The HAC problem can be classified into two categories depending on the source of hydrogen and stress level; one is hydrogen induced cracking (HIC) occurring under no applied stress 2,6 and the other is sulphide stress cracking (SSC) occurring under applied tensile stress or residual stress. 7,8 In order to understand clearly HAC failure of the steels, the combined effect of hydrogen and applied stress should be evaluated together. A number of considerable efforts have been directed to evaluate the influence of applied tensile stress on the hydrogen diffusion behavior in the steel employing the electrochemical permeation technique.9-12 It has been generally accepted that the applied tensile stress in elastic range has no significant effect on the hydrogen diffusivity but increases the steady-state permeation flux due to the elastically expanded lattice. 10,12,13 On the other hand, a significant decrease in the permeation current has been observed in body centered cubic (BCC...

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“…The heterogeneous distribution of these inclusions also favors cracking due to the higher concentration of hydrogen traps in some regions. Segregations associated with high levels of P and S in steel contribute to the accumulation of hydrogen in the material [7,[12][13][14][15][16].…”

Section: Resultsmentioning

confidence: 99%

“…General corrosion is attributed to the preferential dissolution of the ferritic phase and it often manifests by a cementite scale (Fe 3 C) formation. Localized corrosion arises from the galvanic couples between the ferritic phase and nonmetallic (e.g., MnS) or intermetallic (e.g., Fe 3 C) inclusions and it manifests as pitting [6,7].…”

Section: Introductionmentioning

confidence: 99%

A Comparative Study of Hydrogen-Induced Cracking Resistances of API 5L B and X52MS Carbon Steels

Figueredo

Oliveira

Paula

et al. 2018

International Journal of Corrosion

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Susceptibility to hydrogen-induced cracking of API 5L B and X52MS low-carbon steels in NACE 177-A, 177-B, and 284-B solutions has been investigated by the present work. A metallographic analysis of these steels was performed before and after NACE TM0284 standard testing. Corrosion products were characterized by scanning electron microscopy and X-ray dispersive energy spectrometry, which were subsequently identified by X-ray diffraction. Thus it was found that pH directly affects the solubility of corrosion products and hydrogen permeation. Both steels showed generalized corrosion in solution 177-A, and a discontinuous film was formed on their surfaces in solution 177-B; however, only the API 5L B steel failed the HIC test and exhibited greater crack length ratio in solution 177-A. In solution 284-B whose pH is higher, the steels exhibited thick mackinawite films with no internal cracking.

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Role of microstructure and testing conditions in sulphide stress cracking of X52 and X60 API steels

Cited by 34 publications

References 7 publications

Hydrogen Embrittlement of Hardened Low-carbon Sheet Steel

Hydrogen Embrittlement of Hardened Low-carbon Sheet Steel

Determination of Hydrogen Diffusion Parameters of Ferritic Steel from Electrochemical Permeation Measurement under Tensile Loads

A Comparative Study of Hydrogen-Induced Cracking Resistances of API 5L B and X52MS Carbon Steels

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