Quantifying the hydrogen embrittlement of pipeline steels for safety considerations

2012 ◽  
Vol 37 (22) ◽  
pp. 17616-17623 ◽  
Author(s):  
L. Briottet ◽  
I. Moro ◽  
P. Lemoine
Keyword(s):  
Hydrogen Embrittlement ◽  
Pipeline Steels ◽  
Safety Considerations

Effects of Cathodic Protection on Cracking of High-Strength Pipeline Steels

2010 ◽  
Author(s):  
M. Elboujdaini ◽  
R. W. Revie ◽  
M. Attard
Keyword(s):  
Hydrogen Embrittlement ◽  
Cathodic Protection ◽  
Cathodic Polarization ◽  
Water Solution ◽  
Reference Electrode ◽  
High Strength ◽  
Point Of View ◽  
Pipeline Steels ◽  
Different Levels ◽  
Reduction Index

A comparison was made between four strength levels of pipeline steels (X-70, X80, X-100 and the X-120) from the point of view of their susceptibility to hydrogen embrittlement under cathodic protection. The main aim was to determine whether the development of higher strength materials led to greater susceptibility to hydrogen embrittlement. This was achieved by straining at 2×10−6 s−1 after cathodic charging in a simulated dilute groundwater solution (NS4) containing 5% CO2/95% N2 (pH approximately 6.7). The results showed quantitatively the loss of ductility after charging, and the loss of ductility increases with strength level of the steel. All four steels exhibited a loss of ductility at overprotected charging potential and an increasing amount of brittleness on the fracture surface. Ductility in solution was measured under four different levels of cathodic protection, ranging from no cathodic protection to 500 mV of overprotection with respect to the usually accepted criterion of −850 mV vs. Cu/CuSO4 reference electrode. Experiments were carried out by straining during cathodic polarization in a simulated dilute ground water solution (NS-4 solution). Strain rates used were 2×10−6 s−1. After failure, the fracture surfaces were characterized by examination using scanning electron microscopy (SEM). Under cathodic protection, all four steels showed loss of ductility and features of brittle fracture. The loss of ductility under cathodic polarization was larger the greater the strength of the steel and the more active (i.e., more negative) the applied potential. The Ductility Reduction Index (DRI) was defined to quantify the reduction in ductility.

scholarly journals Hydrogen Embrittlement Evaluation of Micro Alloyed Steels by Means of J-Integral Curve

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1843 ◽  
Author(s):  
Marina Cabrini ◽  
Ennio Sinigaglia ◽  
Carlo Spinelli ◽  
Marco Tarenzi ◽  
Cristian Testa ◽  
...  
Keyword(s):  
Hydrogen Embrittlement ◽  
Strain Rate ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Slow Strain Rate ◽  
Slow Strain Rate Test ◽  
Integral Parameter ◽  
Hydrogen Effect ◽  
J Integral ◽  
Pipeline Steels

The aim of this work is the evaluation of the hydrogen effect on the J-integral parameter. It is well-known that the micro alloyed steels are affected by Hydrogen Embrittlement phenomena only when they are subjected at the same time to plastic deformation and hydrogen evolution at their surface. Previous works have pointed out the absence of Hydrogen Embrittlement effects on pipeline steels cathodically protected under static load conditions. On the contrary, in slow strain rate tests it is possible to observe the effect of the imposed potential and the strain rate on the hydrogen embrittlement steel behavior only after the necking of the specimens. J vs. Δa curves were measured on different pipeline steels in air and in aerated NaCl 3.5 g/L solution at free corrosion potential or under cathodic polarization at −1.05 and −2 V vs. SCE. The area under the J vs. Δa curves and the maximum crack propagation rate were taken into account. These parameters were compared with the ratio between the reduction of area in environment and in air obtained by slow strain rate test in the same environmental conditions and used to rank the different steels.

Comparison of hydrogen embrittlement in three pipeline steels in high pressure gaseous hydrogen environments

2012 ◽  
Vol 59 ◽  
pp. 1-9 ◽  
Author(s):  
N.E. Nanninga ◽  
Y.S. Levy ◽  
E.S. Drexler ◽  
R.T. Condon ◽  
A.E. Stevenson ◽  
...  
Keyword(s):  
High Pressure ◽  
Hydrogen Embrittlement ◽  
Gaseous Hydrogen ◽  
Pipeline Steels

Comparison of hydrogen embrittlement susceptibility of three cathodic protected subsea pipeline steels from a point of view of hydrogen permeation

2018 ◽  
Vol 131 ◽  
pp. 104-115 ◽  
Author(s):  
Timing Zhang ◽  
Weimin Zhao ◽  
Tingting Li ◽  
Yujiao Zhao ◽  
Qiushi Deng ◽  
...  
Keyword(s):  
Hydrogen Embrittlement ◽  
Hydrogen Permeation ◽  
Point Of View ◽  
Pipeline Steels ◽  
Subsea Pipeline

scholarly journals In-Situ Hollow Sample Setup Design for Mechanical Characterisation of Gaseous Hydrogen Embrittlement of Pipeline Steels and Welds

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1242
Author(s):  
Tim Boot ◽  
Ton (A. C.) Riemslag ◽  
Elise (T. E.) Reinton ◽  
Ping Liu ◽  
Carey L. Walters ◽  
...  
Keyword(s):  
Hydrogen Embrittlement ◽  
Base Metal ◽  
Pipeline Steel ◽  
Tensile Specimen ◽  
Gaseous Hydrogen ◽  
Fracture Mechanisms ◽  
Cross Sectional ◽  
Pipeline Steels ◽  
Mechanical Characterisation

This work discusses the design and demonstration of an in-situ test setup for testing pipeline steels in a high pressure gaseous hydrogen (H2) environment. A miniature hollow pipe-like tensile specimen was designed that acts as the gas containment volume during the test. Specific areas of the specimen can be forced to fracture by selective notching, as performed on the weldment. The volume of H2 used was minimised so the test can be performed safely without the need of specialised equipment. The setup is shown to be capable of characterising Hydrogen Embrittlement (HE) in steels through testing an X60 pipeline steel and its weldment. The percentage elongation (%El) of the base metal was found to be reduced by 40% when tested in 100 barg H2. Reduction of cross-sectional area (%RA) was found to decrease by 28% and 11% in the base metal and weld metal, respectively, when tested in 100 barg H2. Benchmark test were performed at 100 barg N2 pressure. SEM fractography further indicated a shift from normal ductile fracture mechanisms to a brittle transgranular (TG) quasi-cleavage (QC) type fracture that is characteristic of HE.

The Effects of Pressure Fluctuations on Hydrogen Embrittlement in Pipeline Steels

2016 ◽  
Author(s):  
Xiao Xing ◽  
Mengshan Yu ◽  
Olayinka Tehinse ◽  
Weixing Chen ◽  
Hao Zhang
Keyword(s):  
Stress Intensity ◽  
Hydrogen Embrittlement ◽  
Crack Propagation ◽  
Hydrogen Diffusion ◽  
Hydrostatic Stress ◽  
Accumulation Rate ◽  
Loading Frequency ◽  
Hydrogen Atoms ◽  
Pipeline Steels ◽  
Hydrogen Accumulation

Hydrogen embrittlement is one of the most severe steel degradation mechanisms. Using hydrogen enhanced decohesion (HEDE) and hydrogen enhanced local plasticity (HELP), we can predict if more hydrogen atoms will accumulate into the plastic zone, enhancing the hydrogen embrittlement and the crack growth rate. In the current study, a relationship has been proposed between operations of pipeline steels and hydrogen accumulation to quantify the effects of hydrogen embrittlement. The study find that hydrogen accumulation rate is proportional to stress intensity and inversely proportional to temperature; hence, higher stress intensity and lower temperature will enhance hydrogen accumulation and crack propagation. Hydrogen potential, diffusivity, hydrostatic stress near the crack tip, and the critical loading frequency have been considered in the new model to predict crack propagation rates in pipeline steels. The predicted values are compared with experimental results of X-65 steel in two near-neutral pH solutions to verify the model. This hydrogen diffusion model helps show former neglected hazard operations such as minor cycles, and offers an easier way to optimize operations that will prolong the life of pipeline steels.

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