This paper will discuss the basics of the hydrogen induced cracking phenomenon, the requirements of the nace tm0284 specification and give guidelines for steel production of api pipeline steels that not only can meet the specification requirements the nace testing but also fulfill the other mechanical property requirements. Hic usually occurs due to the effects of aqueous hydrogen charging of steel in wet h2s refinery process environments. An overview of nearneutral ph stress corrosion cracking. When they are in good working order, they deliver fuel to meet the evergrowing demand for energy around the world. The blistering damage tends to form parallel to the surface and to the direction of hoop stress. A focus on different factors affecting hydrogen induced. Hydrogeninduced cracking hic refers to the internal cracks brought about by material trapped in budding hydrogen atoms. One reason it is such a problem is that mic can eat through a pipe or tube in a matter of weeks, or even days, if equipment is left with stagnant, untreated water in it. Hic test apparatus is supplied with essential spares for uninterrupted long term testing. Hydrogen induced cracking of subsea duplex stainless steel twi. Corrosion loops were established for the sour environment and revealed that hic is one of the potential damage mechanisms that could affect the sour gas system. Hydrogen cracking its causes, costs and future occurrence p h m hart weld metal hydrogen cracking in pipeline girth welds, proc.
Steel pipelines and pressurised equipment can operate satisfactorily for up to 8 to 10 years before any cracks are discovered. The terms stepwise cracking swc, hydrogen pressure cracking, blister cracking, and hydrogen induced stepwise cracking have been used in the past to describe cracking of this type in pipeline and pressure vessel steels, but are now considered obsolete. Hydrogen induced cracking test apparatus is rectangular provided with ready to use connections fittings. A small number of duplex and superduplex stainless steel components have failed in subsea service due to hydrogen induced stress cracking hisc. Common fea tures are an applied tensile stress and hydrogen dissolved in the metal due to corrosion or cathodic protection. It is a complex process that is not completely understood because of the variety and complexity of mechanisms that can lead to embrittlement. Inspection and analysis on samples of hydrogen induced crack for.
The corrosion of steel pipelines by hydrogen sulfide has been a recurrent. Hydrogeninduced cracking of steels under wet hydrogen sulfide environment. It should not be confused with the term stress corrosion cracking which is an anodic cracking mechanism. Cracking cracking causes and solutions mistras group. Hydrogeninduced cracking assessment in pipeline steels. Hydrogen accumulation and distribution in pipeline steel in. Corrosionpedia what is hydrogeninduced cracking hic. These steps can help reduce the risk of cracking that leads to costly rework, downtime, increased labor needs, poor productivity and most importantly, product failure. The hydrogeninduced cracking hic behavior of x80 pipeline steel was studied by means of electrochemical charging, hydrogen permeation tests, tension test.
This particular example is a different kind of cracking called hydrogen induced cracking. It involves atomic hydrogen, which is the smallest atom, that diffuses into a metallic structure. The hydrogen induced cracking hic resistance of several grades of plate. Mechanism of failure by hydrogen induced cracking hic in pipeline steel has not been extensively investigated in the past. Hydrogen assisted cracking failures of girth welds in oil and. This paper will discuss the basics of the hydrogen induced cracking phenomenon, the. This is actually a section from a gigantic big pipelines several meters in diameter.
Whats happened is the inside of the pipeline has corroded, its a hydrocarbon, oil, and gas transmission pipeline. It is also called hydrogen assisted cracking hac and delayed cracking since it does not occur right after welding, but a few hours or days after the weld has completely cooled down to ambient temperature. Aug 01, 2018 embrittlement of hydrogen is the main mechanism related to environmental cracking, especially in alloys like titanium and steels. Unfortunately, the term hydrogen induced cracking, usually abbreviated as hic, has been introduced to designate cracking sometimes encountered in pipelines or vessels as a result of hydrogen picked up in service. Factors influencing hydrogen induced cracking welding answers. Susceptible alloys, especially steels, react with hydrogen sulfide, forming metal sulfides and atomic hydrogen as corrosion byproducts. Jun 03, 2018 hydrogeninduced cracking hic refers to the internal cracks brought about by material trapped in budding hydrogen atoms. Factors influencing hydrogen induced cracking welding. Hydrogeninduced cracking resistance of novel cubearing. Hydrogen induced cracking is a mechanical fracture caused by penetration and diffusion of atomic hydrogen into the internal structure of steel, which changes into molecular. Evaluation of pipeline and pressure vessel steels for resistance to hydrogeninduced cracking authors nace international nace international document id nacetm02842016.
The synergistic impact of tensile stress, a susceptible microstructure, and atomic hydrogen can lead to hydrogen embrittlement and the formation of hydrogen cracks. These steps can help reduce the risk of cracking that leads to costly rework, downtime, increased labor needs, poor. Blending hydrogen into natural gas pipeline networks has also been proposed as a means of delivering pure hydrogen to markets, using separation and purification technologies downstream to extract hydrogen from the natural gas blend close to the point of end use. Integrity management of cra pipelines pipeline operators. Hydrogen induced cracking hic hydrogen induced cracking hic may occur in pressure equipment that contains wet hydrogen sulfide h 2 s environments. The mechanism of failure by hydrogen induced cracking in. Hydrogen induced cracking hic laboratory testing assessment of low.
Hydrogen induced cracking hic test results demonstrate that highstrength steels are most susceptible to it, and in the series of x52, x60, x70, and 100xf steels. When it comes to cracked piping and other components which cannot be. Atomic hydrogen, and not the molecule, is the smallest atom and it is small enough to diffuse readily through a metallic structure. Roles of hzs in the behavior of engineering alloys. The significance of these failures has led to research aimed at defining critical conditions for hisc, to allow confident design of components in future. Microbiologically induced corrosion mic is an insidious condition caused by biological growth, typically bacteria, algae, or fungi, in water under low flow or stagnant conditions. Hydrogen induced cracking is also known as cold cracking, delayed cracking or underbead cracking. Hydrogen piping and pipelines pipeline risk management. Ssc is one of the many environmental cracking mechanisms resulting in pipeline steels exposed to aqueous sour service environments. Sulfide stress cracking oil and gas pipelines wiley.
Hydrogeninduced cracking an overview sciencedirect topics. Hydrogen sulphide cracking is a type atom cracking process that helps in breaking down hydrogen atoms from sulphur atoms in aqueous hydrogen sulphide, which is available in crude oil and natural gas. Hydrogen piping and pipelines, yongyi wang hydrogen and safety hydrogen pipelines in service for over 50 years several hundred miles of hydrogen pipelines worldwide no reported injuries due to hydrogen pipelines fire test on hydrogen and gasoline cars, below ref. When the crystal lattice is in contact or is saturated with atomic hydrogen, the mechanical. Hydrogen embrittlement of pipelines and remediation mixing with water vapor.
Hydrogeninduced cracking hic resistance of pipeline steels is one of the most important properties for sour gas service pipelines. Pipelines and pressure vessels made of carbon and low alloy steels have suffered from hydrogen induced cracking hic in wet hydrogen sulfide environment. The ssc of medium strength steels has been a continuing source of trouble in the oil fields, and from these troubles has evolved in international standards 6. Hydrogen induced cracking in pipeline steels corrosion. Evaluation of pipeline and pressure vessel steels for. Hydrogen cracking in general fabrication and particularly pipeline welding is examined. Hydrogen accumulation and distribution in pipeline steel. Hydrogeninduced cracking hic is a far too common type of failure. Mar 24, 2016 electrochemical hydrogen charging and permeation techniques were used to characterize hydrogen distribution, trapping, and diffusion in x60 and x60 sour service x60ss pipeline steels. Hydrogen embrittlement he also known as hydrogen assisted cracking hac and hydrogeninduced cracking hic, describes the embrittling of metal after being exposed to hydrogen. Sulfide stress cracking ssc is just one of several forms of hydrogen.
One reason it is such a problem is that mic can eat through a pipe or tube in a matter of weeks, or even days, if equipment is left with stagnant, untreated water. Hic test specimens are machined with thickness of 530mm, width 20mm, and length of 100mm is suitable for testing as per the nace standard. A comparative study of hydrogeninduced cracking resistances of. Preventing hydrogen induced cracking welding answers. Cracking assessment in sour pipelines product information note strategya is a corrosion software tool for the evaluation of steels in wet h 2 s service in upstream oil and gas environments. If you recall, we mentioned you need all three factors to be present in order to have hic. At the same time, there is sufficient data on the susceptibility of these steels to stress corrosion cracking 6,7,8,9, which in some cases is also explained by hydrogen damage.
The defects are caused when hydrogen blisters form, in turn causing cracks that link these blisters together into larger defects. The hydrogen induced cracking hic behavior of x80 pipeline steel was studied by means of electrochemical charging, hydrogen permeation tests, tension test, and scanning electron microscopy sem. There are probably 3 types of failure modes for line pipe steel in wet hydrothion environment. Chloride pitting corrosion hydrogen induced stress cracking hisc. The mechanism of failure by hydrogen induced cracking in an. The results obtained contribute to better understanding of hydrogeninduced cracking hic. Common causes and cures of hydrogen cracking knowing the means by which hydrogen can enter the weld is a good defense against potential problems. Hydrogen embrittlement he also known as hydrogen assisted cracking hac and hydrogen induced cracking hic, describes the embrittling of metal after being exposed to hydrogen. A focus on different factors affecting hydrogen induced cracking in oil and natural gas pipeline steel article in engineering failure analysis 79 may 2017 with 84 reads how we measure reads.
Blending hydrogen into natural gas pipeline networks. This article discusses hydrogen embrittlement of carbon steel. Software system for cracking assessment in sour pipelines strategya is a corrosion software tool for the evaluation of steels in wet h 2 s service in upstream oil and gas environments. Hic test, hydrogen induced cracking test, step wise. Hydrogen induced cracking of x80 pipeline steel request pdf. Guidelines for production of api pipelines steels suitable for. It is emphasized that hydrogen pipelines currently in service operate in the absence of design criteria against hydrogeninduced failure. Explains why pipeline stress corrosion cracking happens and how it can be prevented. Microbiologically induced corrosion mic inspectioneering. Embrittlement of hydrogen is the main mechanism related to environmental cracking, especially in alloys like titanium and steels. Ssc is one of the many environmental cracking mechanisms resulting in pipeline steels exposed to aqueous sour. Hydrogeninduced cracking hic test results demonstrate that highstrength steels are most susceptible to it, and in the series of x52, x60, x70, and 100xf steels. Hydrogen induced cracking hic is a common form of wet h2s cracking caused by the blistering of a metal due to a high concentration of hydrogen. Hydrogen embrittlement he also known as hydrogen assisted cracking hac and hydrogeninduced cracking hic, describes the embrittling of metal after.
Steels are evaluated in strategya for their tendencies to crack via sul. Processes or conditions involving wet hydrogen sulfide, i. Hydrogen induced cracking hic is a common form of wet h2s cracking caused by. Sem observations illustrated that all hic cracks were formed at the center of cross section in the x60 steel. Hydrogen trapping and hydrogen induced cracking of welded. Stress corrosion cracking scc of pipeline steels in nearneutral ph environments has remained a significant integrity risk for oil and gas pipelines. Sem observations illustrated that all hic cracks were formed at the center of cross section in the x60 steel after 3h. Hydrogen assisted cracking failures of girth welds in oil. History, costs, causes, prediction and trends less frequent incidence but a move from the haz to the weld metal are discussed. Combining action of atomic hydrogen into hydrogen gas is a cumulative process and builds up of hydrogen gas pressure eventually leads to hydrogen induced cracking hlc.
In this paper the discussion is limited to the pipeline industry and stress corrosion cracking. O ur last post factors influencing hydrogen induced cracking went over the factors that contribute to hydrogeninduced cracking. Guidelines for production of api pipelines steels suitable. In the present work, an api x70 pipeline steel was electrochemically charged with hydrogen for different durations in order to find crack nucleation and propagation sites. Hydrogen blistering a special case of hydrogen damage is known as hydrogen blistering. Four types of mechanically and chemically assisted cracking that may occur in industrial equipment include. It involves the ingress of hydrogen into a component, an event that can seriously reduce the ductility and loadbearing capacity, cause cracking and catastrophic brittle failures at stresses below the yield stress of susceptible materials. Hic is susceptible to be presented in the sour gas system because of the. This includes a discussion of the mechanism by which a steel becomes embrittled by hydrgogen, circumstances that lead to embrittlement, the effects of embrittlement on steel behavior, how to prevent the embrittlement, and tests for evaluating whether a steel has been embrittled. An overview of nearneutral ph stress corrosion cracking in. Hydrogen induced cracking hic is one of the most frequent problems in oil and gas pipelines.
Sulfide stress cracking ssc is a form of hydrogen embrittlement which is a cathodic cracking mechanism. Hydrogen permeability and integrity of hydrogen transfer pipelines team. This is a type of deterioration which can be linked to corrosion and corrosioncontrol processes. The hic is a common type of hydrogen damage phenomenon, which refers to the initiation and propagation of microcracks in pipeline steels, especially those used in h 2 s environment, even in the absence of. Susceptibility to hydrogeninduced cracking of api 5l b and x52ms lowcarbon.
Hydrogen induced cracking of pipeline and pressure vessel steels. Hydrogen blistering occurs when hydrogen atoms diffuse into the steel, and hydrogen gas nucleates at internal defects and inclusions, forming voids which eventually generate enough pressure to locally rupture the metal. We will now go over how to prevent hic from happening. Potential threats to cra include but may not be limited to. Hydrogen permeability and integrity of hydrogen transfer. Hydrogen cracking its causes, costs and future occurrence. Jim campbell, air liquide, hydrogen forum, ipc 2006. Cracking occurs due to a significant loss in ductility. Hydrogen induced cracking hic is a failure mechanism resulting in sudden exposures and cracks due to growing laminations inside the base material and welds. Electrochemical hydrogen charging and permeation techniques were used to characterize hydrogen distribution, trapping, and diffusion in x60 and x60 sour service x60ss pipeline steels. Pipelines used to transport oil and natural gas are susceptible to hydrogen induced cracking hic and sulfide stress corrosion cracking sscc in wet h 2 s environments.
Hydrogen embrittlement of steel industrial metallurgists. Offboard gaseous hydrogen storage tanks tank cost and volumetric capacitysame cost optimization as in pipelines. Hydrogen sulphide gas is a poisonous gas and cannot be emitted into the environment without treatment, thus hydrogen sulphide cracking process has. The trapped molecular hydrogen in the mill laminations or voids will have high internal pressure which will cause hydrogen blistering or cracking. It is emphasized that hydrogen pipelines currently in service operate in the absence of any design criteria against hydrogeninduced failure. The results obtained contribute to better understanding of hydrogen induced cracking hic. Cracking is a big problem in many corrosion processes. Which can seriously reduce the ductil ity and loadbearing capacity of the metal, causing cracking and cata.
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