Hydrogen-induced Cracking Behavior Research Articles

Investigation on the hydrogen induced cracking behaviour of heat-treated pipeline steel

In this paper, the hydrogen induced cracking (HIC) sensitivity of the austenitized Cu-containing pipeline steels after cooling processes in air and water conditions was evaluated. Microstructural test, as well as hydrogen-charging slow strain rate tensile test and hydrogen concentration tests were conducted. Results indicated that steels after both cooling processes exhibited lower HIC sensitivity compared to the untreated steel. Elongation and percentage reduction of area after the hydrogen-charging slow strain rate tensile tests were increased. This was related to the formation of strong hydrogen trapping sites and the decrease of weak hydrogen trapping sites such as high-angle grain boundaries. Moreover, the TDS test results confirmed the presence of more stable hydrogen trapping sites in air-cooled steel than water-cooler steel. The latest phenomenon effectively hindered the diffusion behaviour of hydrogen in steel and reduced the HIC sensitivity.

Effect of microstructure on hydrogen embrittlement and hydrogen-induced cracking behaviour of a high-strength pipeline steel weldment

Hydrogen embrittlement (HE) and hydrogen-induced cracking (HIC) behaviour of a X65 steel pipeline weldment were investigated using slow strain rate tensile (SSRT) testing of specimens that were specifically extracted from different zones of the weldment (i.e., weld metal (WM), heat-affected zone (HAZ), and base metal (BM)). The WM was found to be the most susceptible zone to HE and HIC, while BM the least. Analysis of microstructure, fracture surface, secondary crack formation, and mechanical behaviour revealed that the high HE susceptibility of WM is correlated to microstructural features including Ti-rich inclusions, martensite/austenite (M/A) constituents, and prior austenite grain boundaries (PAGBs).

Hydrogen induced cracking behavior of the dual-phase Co30Cr10Fe10Al18Ni30Mo2 eutectic high entropy alloy

In this paper, the hydrogen induced cracking behavior of the Co30Cr10Fe10Al18Ni30Mo2 eutectic high entropy alloy was studied. The results showed that the strength and ductility of the alloy decreased after hydrogen pre-charging, and quasi-cleavage fracture features and hydrogen-induced cracks were found. Moreover, the cracks induced by hydrogen pre-charging were found to propagate along the two-phase interface and inside the BCC phase.

Hydrogen-Induced Cracking in CGHAZ of Welded X80 Steel under Tension Load

X80 steel is extensively used in hydrogen environments and is susceptible to hydrogen embrittlement (HE). This paper studied the hydrogen-induced cracking (HIC) behavior in the coarse-grained heat-affected zone (CGHAZ) of X80 steel welds, through applying in situ hydrogen-charging tensile experiments, hydrogen permeation experiments, and various surface analysis techniques. It is shown that a few hydrogen atoms can significantly decrease a material’s elongation and reduction of area. When the heat input (HI) was 29.2 kJ/cm, the material had minor sensitivity to hydrogen embrittlement. The tensile fractures were ductile without hydrogen. However, the fracture surface exhibited brittle fracture with hydrogen. With increased HI, the HE fracture showed a transition of intergranular fracture→intergranular and transgranular mixed fracture→transgranular fracture. In the presence of hydrogen, the grain boundaries of elongated strips were prone to the formation of intergranular cracks under a tension load, and the hydrogen embrittlement resistance of the bulk lath bainite (LB) was weak. The hydrogen embrittlement susceptibility of pure granular bainite (GB) was lower. Fine LB and GB composite structures could remarkably inhibit intergranular cracks, giving the steel a superior resistance to hydrogen embrittlement.

Molecular dynamics study of hydrogen-induced cracking behavior of ferrite–pearlite gas transmission pipeline steel

Molecular dynamics study of hydrogen-induced cracking behavior of ferrite–pearlite gas transmission pipeline steel

In Situ Investigation of Hydrogen-Induced Cracking Behavior in Linepipe Steel Under Different Environments

NACE MR0175/ISO 15156 provides the severity of a sour environment defined as a function of pH and H2S partial pressure for sulfide stress cracking. Although hydrogen-induced cracking (HIC) is also a major issue of linepipes exposed to a sour environment, the severity diagram does not necessarily correspond to the HIC susceptibility. Recently, from the viewpoint of fitness-of-purpose, the severity diagrams for HIC have been proposed based on the concept of equal hydrogen concentration. From this concept, HIC susceptibility corresponds well to the steady-state hydrogen permeability obtained from the hydrogen permeation test method. In this study, in order to clarify the relationship between HIC susceptibility and hydrogen diffusion behavior, in situ crack inspection during the HIC test and finite element method analysis of hydrogen diffusion were performed. The in situ inspection technique using phased-array ultrasonic testing which can capture the time dependence of crack distribution, and HIC initiation and propagation behaviors were clearly visualized and investigated. It was found that crack initiation and propagation stabilize as hydrogen concentration reaches a steady-state value throughout the specimen and the result was considered evidence that the HIC susceptibility corresponded with the steady value of hydrogen permeability.

Investigation of the hydrogen-induced cracking of E690 steel welded joint in simulated seawater

Hydrogen-induced cracking (HIC) behavior and mechanism of E690 welded joint in simulated seawater were studied via microstructure observations, electrochemical hydrogen charging, slow strain rate tension (SSRT) tests and hydrogen content measurement. The results show that the welded joint of E690 steel has a higher HIC susceptibility than that of base metal, in which the inter-critical heat affected zone (ICHAZ) is composed of polygonal ferrite and granular bainite is the final fracture location in the joint. ICHAZ with the lowest yield strength deformed preferentially under the tensile stress, and subsequently, the proliferating dislocations with the deformation strengthening and the continuously charged hydrogen led to the HIC and brittle fracture at the ICHAZ of the welded joint. Moreover, the HIC susceptibility was linearly dependent on the logarithm of total hydrogen concentration in the steel, and the hydrogen concentration had a more obvious effect on the welded joint than the base metal. The higher density of piled dislocations adjoining the M/A islands in the welded joint exhibited a significant effect on the hydrogen agglomeration and diffusion, which enhanced the HIC susceptibility.

Analysis and Prediction of Nonmetallic Inclusions and Their Effect on Hydrogen Induced Cracking Behavior of X65 Acid-resistant Pipeline Steel

Analysis and Prediction of Nonmetallic Inclusions and Their Effect on Hydrogen Induced Cracking Behavior of X65 Acid-resistant Pipeline Steel

Hydrogen-induced cracking and corrosion behavior of friction stir welded plates of API 5L X70 pipeline steel

The use of friction stir welding (FSW) has proven to be an excellent alternative to join engineering components. Although FSW has had a significant development in recent years, challenges for new applications have been raised, such as offshore steel parts suffering hydrogen embrittlement in the gas and oil industry. Therefore, in this work, the microstructure, corrosion, and hydrogen-induced cracking were investigated in a two-pass FSW welded joint of API 5L X70 pipeline steel. The electrochemical results indicate an inhibitory effect on corrosion reaction because of a carbonate product generation in the steel surface. The polygonal ferritic and degenerated pearlite bands microstructure in the base metal fixed carbonate deposits in the steel surface. In the welded regions, the bainitic microstructure and the carbide particle distribution are less efficient in setting the weld surface carbonate deposit. HIC tests showed cracks initiation and propagation to be more prone in hard phases.

Numerical Simulation on Effect of Microstructure on Hydrogen-induced Cracking Behavior in Duplex Stainless Steel Weld Metal

Numerical Simulation on Effect of Microstructure on Hydrogen-induced Cracking Behavior in Duplex Stainless Steel Weld Metal

Evaluation of Hydrogen-induced Cracking Behavior in Duplex Stainless Steel by Numerical Simulation of Stress and Diffusible Hydrogen Distribution at the Microstructural Scale

Evaluation of Hydrogen-induced Cracking Behavior in Duplex Stainless Steel by Numerical Simulation of Stress and Diffusible Hydrogen Distribution at the Microstructural Scale

Correlation between Microstructure and Hydrogen Degradation of 690 MPa Grade Marine Engineering Steel.

Electrochemical H charging, hydrogen permeation, and hydrogen-induced cracking (HIC) behavior of 690 MPa grade steel substrate and different heat-treatment states (annealed, quenched, normalized, tempered) are investigated by cyclic voltammetry (CV), hydrogen permeation, electrochemical H charging, and slow strain rate tensile test (SSRT). The results show that hydrogen diffuses through the steel with the highest rate in base metal and the lowest rate in annealed steel. The hydrogen-induced cracks in base metal show obvious step shape with tiny cracks near the main crack. The cracks of annealed steel are mainly distributed along pearlite. The crack propagation of quenched steel is mainly transgranular, while the hydrogen-induced crack propagation of tempered steel is along the prior austenite grain boundary. HIC sensitivity of base metal is the lowest due to its fine homogeneous grain structure, small hydrogen diffusion coefficient, and small hydrogen diffusion rate. There are many hydrogen traps in annealed steel, such as the two-phase interface which provides accommodation sites for H atoms and increases the HIC susceptibility.

Characterising hydrogen induced cracking of alloy 625+ using correlative SEM - EDX and NanoSIMS

Hydrogen induced cracking behaviour of O&G nickel alloy 625+ (UNS N07716) was investigated. Deuterium was introduced electrochemically into samples by cathodic polarisation (3.5 wt.% NaCl.D2O) under different mechanical conditions. Subsequently, deuterium distributions were mapped using NanoSIMS. Deuterium was used as an isotopic tracer instead of hydrogen to avoid the detection of hydrogen artefacts. Complimentary image analysis using scanning electron microscopy (SEM) and low voltage energy dispersive X-ray (EDX) allowed the identification of microstructural features corresponding to deuterium enrichments. The results provided experimental evidence of enrichments at dislocation slip bands (DSB), twin boundary and grain boundary features that include σ precipitates.

A review on the effect of microstructure on hydrogen induced cracking behaviour in pipeline and pressure vessel steels

Recently, the demand for energy is increasingly higher, and to meet the demand, more pipeline and pressure vessels are used to transport and store energy. Steels served in such environment need to have basic mechanical property, as well as excellent hydrogen induced cracking performance. Because hydrogen induced cracking failure will not only cause huge economic losses, but also have a harmful impact on the environment, it is necessary to study the impact of hydrogen induced cracking on steel and how hydrogen induced cracking occurs and expands. In this paper, the most important factor affecting hydrogen induced cracking, microstructure, was introduced.

Investigation of the hydrogen induced cracking behaviour of API 5L X65 pipeline steel

The effect of microstructural features on the hydrogen induced cracking (HIC) susceptibility of two API 5L X65 pipeline steels were investigated by cathodic charging, hydrogen permeation and hydrogen microprint experiments. Microstructural evaluation after hydrogen charging revealed cracks at the mid-thickness (segregation zone) of both plates. However, more severe cracks were observed in the plate with higher dislocation density and residual stresses. The plate with lower plastic strain and more {111}-oriented grains had less severe cracks. Inclusions found along the crack path, comprising of Si-enriched oxides and carbides contributed to the initiation and propagation of cracks. The variation of the trapping behaviour and hydrogen diffusion through the plates were examined. The results confirmed that a higher ratio of reversible to irreversible traps contributes to increasing HIC severity in steels. Additionally, hydrogen transport through the steels was most prominent along the grain boundaries, indicating the importance of grain boundary character to HIC.

Effect of Microstructure on Hydrogen Induced Cracking and Hydrogen Trapping Behavior of X100 Pipeline Steel

Effect of Microstructure on Hydrogen Induced Cracking and Hydrogen Trapping Behavior of X100 Pipeline Steel

Numerical Simulation on Effect of Microstructure on Hydrogen-induced Cracking Behavior in Duplex Stainless Steel Weld Metal

Numerical Simulation on Effect of Microstructure on Hydrogen-induced Cracking Behavior in Duplex Stainless Steel Weld Metal

Evaluation of Hydrogen-induced Cracking Behavior in Duplex Stainless Steel by Numerical Simulation of Stress and Diffusible Hydrogen Distribution at the Microstructural Scale

Evaluation of Hydrogen-induced Cracking Behavior in Duplex Stainless Steel by Numerical Simulation of Stress and Diffusible Hydrogen Distribution at the Microstructural Scale

Hydrogen-Induced Cracking of Laser Beam and Gas Metal Arc Welds on API X65 Steel

Hydrogen-induced cracking (HIC) behavior was analyzed for gas metal arc (GMA) and laser beam (LB) welds on American Petroleum Institute (API) X65 steel. The GMA welds consisted of acicular ferrite (AF) with some widmanstatten ferrite (WF), while the LB welds had bainitic ferrite (BF) with some AF. The welds and heat affected zone (HAZ) of GMA exhibited a hardness of 220-250 HV, while those of the LB had a hardness of 230-290 HV. The LB welds and HAZ exceeded the hardness limit of 250 HV for pipeline steel, defined by the National Association of Corrosion Engineers (NACE) standard. Slow strain rate tests (SSRT) were performed in air and in-situ with hydrogen to observe HIC behavior. The ultimate tensile strength of the GMA welds decreased by 13%, while that of the LB welds decreased by 16% after hydrogen charging. Both welds showed a dimple fracture in the center and quasi-cleavage fracture along the edges. When austenite transforms to BF, it is known to grow along the directions of twins or the Kurdjumov-Sachs relation. These directions are strongly related to the coincidence site lattice, specifically Σ3 and Σ13b, and have good crack resistance. Because of this grain boundary characteristic, the LB welds with a BF microstructure showed good HIC behavior compared to the GMA welds. (Received May 7, 2019; Accepted June 12, 2019)

Effect of Hydrogen Content and Strain Rate on Hydrogen-induced Delay Cracking for Hot-stamped Steel

Hot-stamped steel has been widely used in automobile bumper and other safety components due to its high strength. Therefore, this paper investigates the effect of hydrogen content and strain rate on hydrogen-induced delay cracking (HIDC) behavior. The results showed that the plasticity of the steel significantly decreased with an increase in hydrogen content or a decrease in the strain rate. Fractography was analyzed after tensile tests. It was found that all of the pre-charged specimens cracked at large-sized inclusions when stretched at a strain rate of 1 × 10−3 s−1, which indicates that, in this case, the defect itself in the material had great influence on the extend properties. No inclusions were found at the main fracture origin area for hydrogen steady-state specimens, when stretched at a strain rate of 1 × 10−6 s−1, which demonstrated that a slower strain rate causes greater influence by hydrogen. However, for the non-pre-charged samples, the fractures surface showed that cracking originated from the defect near the sample surface, which was independent of strain rates.