Hydrogen Induced Cracking Test Research Articles

Research on hydrogen induced cracking (HIC) performance of vessel steels

Hydrogen-induced cracking performance is quite important for vessel steels. But for this type of medium carbon steel, studies on the effect of the dislocation density and distribution condition of carbides on hydrogen-induced cracking performance were insufficient. In this study, the tested steel was treated with three different heat-treatment processes: scanning electron microscopy (SEM), hydrogen-induced cracking tests (HIC), and transmission electron microscope (TEM), which were used to reveal the mechanism of affecting hydrogen-induced cracking performance. The results showed that microstructure, dislocation density, and distribution condition of carbides were the significant key to the hydrogen-induced cracking performance of tested steels. As the tempering temperature grew from 450°C to 650°C, the density of dislocation gradually went down from 9.71/1010 cm-1 to 2.97/1010 cm-1. And the shape of carbides transformed from bar into fine particles, and the area fraction increased from 37% to 44%. More uniformly distributed carbides can enhance hydrogen-induced cracking resistance because it can promote trapped hydrogen atoms uniformly distribute, reduce the local hydrogen pressure and prohibit crack initiation and propagation. In other words, a tempering temperature above 550°C would be beneficial for the hydrogen-induced cracking performance of vessel steels.

Analysis of the Cause of Gas Pipeline Burst in a Gas Production Plant

In order to reduce the failure of pipes, the macroscopic morphology, macroscopic crack, chemical composition, hardness, microstructure and so on were tested through the macroscopic analysis, physical and chemical property inspection, hydrogen-induced cracking test and sulfide stress cracking test. The SEM was used to analyze the microscopic cracks, fractures and element distribution at the failure site. The results show that the cracking zone of the failed pipe section has the characteristics of bulging deformation and thinning of wall thickness. The macroscopic fracture of the fracture is a typical 45° shear shape. The fracture was observed under the high magnification of scanning electron microscope and showed dimple morphology. The failure mode of the failed pipe segment is plastic fracture. The reason for the failure of this pipe is the special geographical location of this section of the pipeline, and the sudden increase of pipeline pressure after the well opening operation causes the water hammer phenomenon, which causes the local bulging of the pipe body, which further leads to burst failure.

The effect of non-metallic inclusion morphology on the hydrogen induced cracking (HIC) resistance of L80 steel

The hydrogen induced cracking (HIC) resistance of four (4) L80 casing steels, with different nominal compositions and processing conditions, was determined using the NACE TM0284 HIC test. Microstructural and inclusion characterization of each steel was undertaken using optical microscopy (OM), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The morphology (equivalent diameter, aspect ratio and major length) of inclusions over identical analysis regions were measured for each steel. In total, >15,000 inclusions were characterized. Non-linear models correlating inclusion morphology with the measured values of CLR (crack length ratio) and CTR (crack thickness ratio) were developed. The models show that both CLR and CTR are complex functions of the diameter (equivalent) of oxide-based inclusions and the major length of the manganese sulfide (MnS) stringers. The models show that oxides <10 μm in diameter were found to have negligible effect on HIC resistance (CLR) while oxides >20 μm exhibited a significant and escalating negative impact on HIC resistance comparable to long (>50 μm) MnS stringers.

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.

Hydrogen induced cracking and stress corrosion cracking behavior of the weld metals in 17‐4 precipitation hardening stainless steel after double over aging treatment

AbstractThis research studied the effect of two‐stage over aging treatment on corrosion behavior of the weld metals in the 17‐4 precipitation hardening stainless steel. Gas tungsten arc welding was performed under solution annealed condition. After the welding, weld metal was subjected to double over aging treatments. Hydrogen induced cracking and stress corrosion cracking standard tests were carried out on weld metals before and after ageing treatment. Charpy impact test and microhardness test were conducted to evaluate the mechanical properties of weld metals. Microstructural examinations of the welding zones were performed by the optical microscope and field emission scanning electron microscope. The results showed that the as‐weld lath and coarse martensite were transferred to severely tempered martensite after over aging treatment with the formation of reversed austenite. In the latter case, the reversed austenite was about 30 % compared to 7 % before over aging treatment. The over aged weld metals were significantly more resistant to hydrogen induced cracking, and exhibited a longer time‐to‐failure in stress corrosion cracking test. The weld metal in the as‐weld condition in hydrogen induced cracking test showed severe cracking and failed rapidly in the stress corrosion cracking test.

Effects of Mn and Microalloying Composition on Corrosion and Hydrogen-Induced Cracking of API 5L X65 Steels

The corrosion and hydrogen-induced cracking (HIC) resistance as well as hydrogen permeation behavior of two API 5L X65 steels with different amounts of Mn and microalloying elements were compared. The corrosion behavior of both steels, evaluated using electrochemical impedance spectroscopy and polarization curves in solution A of NACE TM0284-16 standard with and without H2S saturation (sour medium), showed no relevant differences in each medium, which can be ascribed to their similar microstructures; however, the corrosion resistance of both steels was lower in the sour medium. The investigation of resistance to hydrogen-induced failures disclosed better performance for the low Mn steel. This was confirmed using a harsher HIC test performed in an HCl acidified sour medium and was ascribed to the presence of Nb carbides nanoprecipitates, as revealed by the scanning transmission electron microsccopy analysis.

HIC and SSC of Carbon Steel in High Partial Pressure CO2 Environments with Elevated H2S

The Hydrogen Induced Cracking (HIC) and Sulfide Stress Cracking (SSC) behaviours of sour service and non-sour service carbon steel API 5L X65 were investigated under high pressure carbon dioxide environments, containing elevated amount of hydrogen sulphide (H2S); the test environments simulated offshore pipelines transporting full-well streams in high carbon dioxide (CO2) environments with elevated H2S concentrations. It was systematically studied under standard NACE condition and high pressure carbon dioxide field condition with variation in other key parameters (temperature, pressure and hydrogen sulfide concentration). The HIC and SSC were tested using a High Pressure and High Temperature (HPHT) Autoclave. The surface cracking morphology was analysed using Scanning Electron Microscopy (SEM), Ultrasonic Technique (UT) and Magnetic Particle (MP). The results showed that no cracks were detected in NACE standard and field-condition SSC tests for both sour service and non-sour services carbon steel. In HIC test, crack was detected on non-sour service carbon steel in NACE standard test while no crack was detected on field condition-based tests for both types of carbon steel.

Hydrogen Sulfide in Wastewater Generated by Hydrogen Induced Cracking Test: Cause and Safety Measures

During the process of treating various wastewater, toxic gas such as hydrogen sulfide is generated due to the chemical reaction among unknown chemicals contained in wastewater, causing an accident that kills or injures workers and requires evacuation of people in neighboring areas. This study tested the reaction of sodium hydrogen sulfide generated during hydrogen induced cracking with sulfuric acid to confirm the occurrence of hydrogen sulphide and proposed safety countermeasures to prevent similar disasters from recurring. Hydrogen sulphide gas used during the process of hydrogen organic crack test reacts with sodium hydroxide in a neutralization tank and a gas scrubber to produce sodium hydrogen sulphide. Highly toxic hydrogen sulphide gases are produced violently when wastewater containing sodium hydrogen sulfide is mixed with sulfuric acid wastewater. In order to prevent the occurrence of harmful gases due to adverse reactions during wastewater treatment, the process of generating consigned wastewater should be well identified in advance, along with the detailed information on the composition and properties of the wastewater. In addition, more attention should be paid to adverse reactions of mixed wastewater.

Effect of electrochemical hydrogen charging on an API X70 pipeline steel with focus on characterization of inclusions

Environmental conditions of service affect the resistance of pipeline steels to failure, as a result, the applied stress which would be otherwise considered safe can be responsible for fracture due to hydrogen induced cracking (HIC). The presence of hydrogen sulfide in natural gas is one of the main sources of hydrogen in steel. HIC testing showed that cracks initiated from inclusions and propagated through the steel matrix along the crack path that was occupied by inclusions. The number of inclusions and the distance between them as well as the grain size between them was considered to be important for predicting failure. Shorter distance between inclusions and smaller grains were found to facilitate HIC propagation. The hydrided specimens were subjected to tensile stress until failure to generate stress-strain curves, ductility and toughness data. It was revealed that even though most of the cracks initiate from rectangular and spinel inclusions, the globular inclusions have also contributed to reducing the tensile strength, ductility and toughness. Synchrotron radiation 3D imaging of steel structure was used to explain the features of the HIC cracks formation during tensile tests.

Investigation of the corrosion process and destruction of metals by using acoustodamage method

The paper presents the results of investigation of acoustic anisotropy in industrial alloy made of steel 14HGNDC after hydrogen-induced cracking (HIC) tests according to the standard NACE TM0284-2003. It was found that location and parameters of corrosion cracks with size about 20 microns can be determined by distribution and value of acoustic anisotropy. A quantitative relationship between value of acoustic anisotropy and size of corrosion cracks in the range from 60 to 6600 microns was established. The obtained results have a great importance for improving methods of hydrogen-induced cracking tests and for non-destructive testing of brittle destruction of structures in oil and gas industry by using the acoustodamage method.

In Situ Observation of Hydrogen-Induced Cracking Propagation Behavior

Hydrogen-induced cracking (HIC) is one of the major issues of line pipe exposed to sour environments. There are some guidelines on materials requirements for carbon and low alloy steels for H2S-containing environments in oil and gas production. Generally, HIC susceptibility is evaluated after the test duration, typically 96 h, in accordance with NACE Standard TM0284-2016. However, HIC propagation behavior during HIC test has not been fully understood. In this study, a new in situ HIC measurement method has been developed in order to make the connection between HIC propagation behavior and microstructure. This technique is based on the combination of an automatic ultrasonic wave inspection system and a scanning electron microscopy (SEM) observation. HIC propagation rate and HIC propagation behavior of carbon steels with different textures were investigated, using this in situ technique. Texture components of tested steels were changed by controlled rolling process in the alpha-gamma dual phase region. The {100} intensity parallel to the rolling plane was developed with increasing controlled rolling reduction in the alpha-gamma dual phase region. HIC propagation rate increased and crack length of HIC grew in a staircase pattern with time when the {100} texture was highly developed. In addition, HIC propagation behavior could be overlapped with fracture surface, just like a projection mapping. The overlapping could make the connection between HIC propagation behavior and HIC fracture surface. Microstructure and texture just under the HIC fracture surface was also characterized by SEM and an electron backscatter diffraction pattern method. The results obtained in this study showed that HIC propagation behavior was affected by a texture. In addition, the new in situ HIC observation technique, which can make the direct connection between HIC propagation behavior and microstructure, revealed a detailed HIC propagation behavior and an effect of microstructure.

Effect of Zr–Ti deoxidisation on the hydrogen-induced cracking of X65 pipeline steels

The effect of Zr–Ti combined deoxidisation, compared with the traditional Al deoxidisation, on inclusion and microstructure in X65 pipeline steels was investigated by means of analytical characterisation techniques such as non-aqueous solution electrolysis method, optical and electron microscopy in conjunction with energy dispersive X-ray spectroscopy and hydrogen-induced cracking test. Large inclusions as well as elongated MnS particles were observed in the conventional Al-deoxidised steel. However, the type and size of inclusions were efficiently controlled in the Zr–Ti-deoxidised steel, in which MnS particles were spheroidised and evenly dispersed in the matrix. Hydrogen-induced cracking test results showed that centre segregation was the main factor accountable for hydrogen-induced cracking in X65 pipeline steels. The Zr–Ti-deoxidised X65 pipeline steel revealed better HIC-resistance performance.

Novel Cu-bearing high-strength pipeline steels with excellent resistance to hydrogen-induced cracking

There is a great challenge to simultaneously improve strength and resistance to hydrogen-induced cracking (HIC) for pipeline steels. In this study, through copper (Cu) alloying, a novel type of pipeline steel was developed to meet the requirement for both high strength and excellent resistance to HIC. The HIC tests of the tentative pipeline steels and the comparison steel were conducted in a hydrogen sulfide (H2S) saturated solution according to NACE standard. The results showed that an acicular ferrite microstructure with uniformly distributed fine Cu-rich precipitates was obtained by aging at 500°C for 1h. Nano-scale Cu-rich precipitates in the new steels were speculated to play a significant role in making precipitation strengthening and providing beneficial hydrogen traps. The Cu-bearing pipeline steel has achieved a high strength grade of API X120 with excellent resistance to HIC.

Laboratory testing of steel L360NB, L80, J55 resistance to sulphide stress cracking SCC and hydrogen induced cracking HIC

Results of laboratory study of 3 types of steel, resistance to sulphide stress cracking and hydrogen induced cracking in H2S environments, are presented in this article. Those steels have been applied in the petroleum industry. Determining the threshold of safety for each type of steel (with regard to yield strength Re) below where stress cracking won’t occur was possible owing to these examinations. Hydrogen induced cracking test was applied to research steel resistance to cracking caused by hydrogen from sulphur aqueous environments. These tests permit determination of the threshold of safety of a given material to be admitted for use in hydrogen sulphide environments.

Effect of Microstructure on Hydrogen Induced Cracking Behavior of a High Deformability Pipeline Steel

The hydrogen induced cracking (HIC) behavior of a high deformability pipeline steel was investigated with three different dual-phase microstructures, ferrite and bainite (F+B), ferrite and martensite/austenite islands (F+M/A) and ferrite and martensite (F+M), respectively. The HIC test was conducted in hydrogen sulfide (H2S)-saturated solution. The results showed that the steels with F+B and F+M/A dual-phase microstructures had both higher deformability and better HIC resistance, whereas the harder martensite phase in F+M microstructure was responsible for the worst HIC resistance. The band-like hard phase in dual-phase microstructure was believed to lead to increasing susceptibility to HIC.

Hydrogen Response of 304 SS and Ti Weld Realised by Explosion

Welds of thick plates (304 SS) cladded with Ti of commercial purity both in as received state and subsequently heat treated (HT, 600°C/1.5 h/air), charged by hydrogen, were investigated after fatigue tests (tension-pressure) with amplitude of 20 Hz. Simultaneously, samples of above mentioned welds were also exposed in H2S in accord with NACE Standard TM0284-2011 to find hydrogen induced cracking (HIC) response. Charged welds after the HT showed by 15 MPa higher threshold level than the welds without the HT. The HIC tests generally demonstrated favourable results both after as weld state and after subsequent HT. Short and thin cracks were observed, exclusively located in intermetallic phase areas, where approx. 16-20 wt. % of Ti was revealed. Fracture surfaces of fatigue bars showed maximal failure in areas with 42-97 wt. % of Ti.

Failure Analysis on Fracture of a S135 Drill Pipe

The fracture of drill pipe is mainly controlled by the material of drill pipe and environment of operation, which maybe induces huge loss of economy and society. A fractured 3 1/2″ S135 drill pipe was analyzed through physical and chemical properties, Scanning Electron Microscope (SEM) and Energy Dispersive Spectrometer (EDS) method. Additionally, a series research about sulfur resistance of S135 was also estimated by sulfide stress cracking test and hydrogen-induced cracking test. The results showed that the failure of the drill pipe was belong to sulfide stress corrosion cracking. High H2S content condition and the material with high strength leaded to the final rupture of the drill pipe. The application of drill pipe with high strength was also proposed on the basis of above results and discussion.

Evaluation of Stress Corrosion Resistance Properties of 15CrMoR(H) in H&lt;sub&gt;2&lt;/sub&gt;S Environment

Tests including the constant load tensile, three point bending and hydrogen induced cracking (HIC) are executed to evaluate the comprehensive properties of the 15CrMoR(H) with new smelting process in saturated hydrogen sulfide (H2S) according to NACE and National Standard. By analyzing and fitting the results of constant load tensile test, the stress-life mathematical model of this material is given. Results show that the stress corrosion threshold of the constant load tensile is 0.7Rel (252MPa).The nominal stress of three point bending SC is higher than 4.5 Rel (1620MPa). Results of HIC test show that the crack length rate CLR is 4.40%, the crack thickness rate CTR is 0.87% and the crack sensitive rate CSR is 0.04%. According to EFC standard, the safety margin is 3.4, 3.4 and 37.5 times respectively. All the experimental results show that the 15CrMoR(H) material has excellent H2S stress corrosion cracking resistance properties.

Hydrogen induced cracking susceptibility in different layers of a hot rolled X70 pipeline steel

Hydrogen induced cracking (HIC) behaviour was investigated in three layers of RD–ND plane. HIC test showed that all cracks initiated from the mid-thickness of the RD–ND plane and propagated in the rolling direction of the steel plate. Hydrogen permeation test results showed a lower permeability and diffusivity coefficient for the third layer resulting in the highest density of traps and consequently HIC susceptibility. Considering the HIC test and crystallographic texture measurements, cracks initiated from the grain boundaries associated with {100} grain orientation and arrested in regions with some strong texture components, such as {110}//ND, {112}//ND, and possibly {332}//ND. The role of HABs and CSLs boundaries was important in crack propagation.

A comparative study of hydrogen induced cracking behavior in API 5L X60 and X70 pipeline steels

Hydrogen induced cracking (HIC) in pipeline steels industry causes a huge amount of economic loss to the industry, but despite this, HIC behavior is still not fully understood. We have studied HIC behavior in API 5L X60 and X70 pipeline steels using analysis of hydrogen permeation, hydrogen discharge using microprint technique, HIC standard test and their correlation with microstructure, type and morphology of inclusions. We recognized that mixed oxide inclusions do not seriously influence HIC in either steel. HIC tests in both steels demonstrated that the zone at the thickness center has a high concentration of manganese, silicon and sulfur and most cracks nucleate around this zone. Manganese sulphide inclusion, the most harmful type, was not present in the X60 steel specimen but was found in the center of the cross section of the X70 steel. We recognized a linear correlation between HIC susceptibility and hardness value in both steels. Furthermore, we calculated the number of reversible and irreversible hydrogen trapping sites and amount of discharged hydrogen for both steels through hydrogen permeation test. The obtained results show that the role of reversible hydrogen trapping sites on HIC susceptibility and crack growth is very important. Finally, Hydrogen microprint technique (HMT) test-data demonstrated that there was rather uniform distribution of hydrogen discharge through the grains in both steels; however, the concentration of hydrogen at grain boundaries was higher than in other areas.