However, it may take longer for the cracks to grow. A saudi aramco gas processing plant commissioned in 1980 to process wet sour gas streams and produce dry sweet sales gas in addition natural gas liquid ngl. Susceptibility to hydrogeninduced cracking of api 5l b and x52ms lowcarbon steels in nace 177a, 177b, and 284b solutions has been investigated by the present work. This is a problem commonly found in wet h2ssour service operating environments such as in the oil, gas and petrochemical industry. Corrosionpedia what is hydrogeninduced cracking hic.
S service in elevated pressure and temperature profiles. Regarding applications in the oil and gas industry, hydrogeninduced cracking can occur on a very wide variety of steel equipment. Initiation of stress corrosion cracking and hydrogen. Examples of internal hydrogen embrittlement include processes such as. Hughes 1880 note on some effects produced by the immersion of steel and iron wires in acidulated water. 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. This is a type of deterioration which can be linked to corrosion and corrosioncontrol processes. These internal cracks may propagate by a process called hydrogeninduced cracking hic or hydrogen blistering. Abstract hydrogeninduced cracking hic has been studied phenomenologically.
Hydrogeninduced cracking hic has been studied phenomenologically. The factors influencing the occurrence of hydrogeninduced cracking hic in steel plates have been investigated by means of ultrasonic cscanning of. Hydrogen blistering a special case of hydrogen damage is known as hydrogen blistering. 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. Summary hydrogen induced cracking hic is a materials and corrosion related. Hydrogen induced cracking test tank test methods nace tm0284 astm g39 material of construction polypropylene, pvc, or glass capacities up to 55 liters cortest offers a variety of different hydrogen induced cracking hic test tank designs that can be used to study the corrosive and embrittling effects on a metal sample in a hydrogen enriched. Hydrogen induced cracking of hard materials zthe refining industry has had very few cases of hydrogen related cracking in pure hydrogen service. A detailed assessment study was conducted in this plant pertaining to hydrogen induced cracking hic. 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. Johnson 1875 on some remarkable changes produced in iron and steels by the action of hydrogen acids.
Handbook of materials failure analysis with case studies from the oil and gas. Ansinace tm02842016, evaluation of pipeline and pressure vessel steels for resistance to hydrogeninduced cracking available for download test conditions for evaluation of pipeline and pressure vessel steels. The principal distinguishing feature of this type of crack is that it occurs in ferritic steels, most often immediately on welding or a short time after welding. Sulfide stress cracking ssc vs hydrogen induced cracking hlc posted in refining, hydrocarbons, oil, and gas. As we know that both form of cracking are due to the absorption of atomic hydrogen that. The steel grades carbon, stainless, as well as nickelbased alloys, used cover a. 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. Common causes and cures of hydrogen cracking fabricating. Factors influencing hydrogen induced cracking welding. A process is provided for treating crude oil to visbreak andor upgrade such oil using hydrogen gas.
O ur last post factors influencing hydrogen induced cracking went over the factors that contribute to hydrogeninduced cracking. Generally, hic susceptibility is evaluated after the test duration, typically 96 h, in accordance with nace standard tm02842016. Thorough cleaning of weld joint at least 25mm on either side, inside and outside if joining a pipe removes grease, oil, coatings, water etc. Effect of microstructure on hydrogeninduced cracking of. Defects hydrogen cracks in steels identification twi. A metallographic analysis of these steels was performed before and after nace tm0284 standard testing. The effect of microstructure on hic is discussed for steels having two different levels of nonmetallic inclusions. 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.
Hydrogen induced cracking of pipeline and pressure vessel. Hydrogen induced cracking steel features, applications. Hydrogeninduced cracking hic in steel is a risk problem when steels are charged with hydrogen in service as in various hydrogen sulfide environments like sour oil and gas wells and some power plants. Corrosion loops were established for the sour environment and. Hydrogeninduced cracking can also occur in the weld metal itself and when it does, it is typically transverse to the weld direction. Hydrogeninduced cracking in surface production systems.
Hydrogen induced cracking in hy80 steel weldments direct observation of crack initiation and propagation, using an improved straining device, serves to clarify the role of hydrogen and the effect of rare earth additions by w. Analysis of hydrogen induced cracking by insitu hic observation. A comparative study of hydrogeninduced cracking resistances of. Hic steel hydrogen induced cracking supplier company.
Hydrogen sulphide gas is a poisonous gas and cannot be emitted into the environment without treatment, thus hydrogen sulphide cracking process has. If you recall, we mentioned you need all three factors to be present in order to have hic. In alkylation, low molecular weight compounds, such as propylene and butylene, are mixed in the presence of a catalyst such as hydrofluoric acid or sulfuric acid a byproduct from removing impurities from many oil. Fluid catalytic cracking is a commonly used process, and a modern oil refinery will typically include a cat cracker, particularly at refineries in the us, due to the high demand for gasoline. Hydrogen embrittlement he also known as hydrogen assisted cracking hac and. Hydrogeninduced cracking hic is one of the major issues of line pipe exposed to sour environments. Hydrogen cracking may also be called cold cracking or delayed cracking.
The hydrogen deleterious effect has a relevant industrial and economic impact being, at the same time, a challenge from the scientific point of view. Preventing hydrogen induced cracking welding answers. There are at least three factors which, with respect to influencing the risk of hydrogen cracking, can be considered specific to girth welds in pipe. Detail hobart brothers performance welding products. Mechanism of cracking in the presence of h2s, the process of cracking hic can be divided in to 5 stages 1 corrosion.
Initiation of stress corrosion cracking and hydrogeninduced cracking in oil and gas. Hydrogeninduced cracking an overview sciencedirect topics. Common causes and cures of hydrogen cracking knowing the means by which hydrogen can enter the weld is a good defense against potential problems. Hydrogeninduced cracking hic is still a challenging issue that requires. It is a complex process that is not completely understood because of the variety and complexity of mechanisms that can lead to embrittlement. No external stress on test specimens is usually required to examine this type of cracking. Investigation of oil and natural gas pipelines failure by hydrogen. Chemical processing how oil refining works howstuffworks. Abstract hydrogen induced cracking hic is one of the major issues of line. Hic can be prevented, or even reversed, through several process which focus on ensuring that no contact is made between the metal and hydrogen. It involves atomic hydrogen, which is the smallest atom, that diffuses into a metallic structure. This pressure will rise with time and cause reduction in the metals ductility and tensile strength, leading to hydrogeninduced cracking hic. 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 which is produced at cathode due to corrosion reaction, diffuses into the steel and result in cracking in wet hydrogen sulfide environment.
The blistering damage tends to form parallel to the surface and to the direction of hoop stress. The degradation of structural integrity in the presence of hic may advance slowly or rapidly depending on the operational conditions. Susceptibility to hydrogeninduced cracking of api 5l b and x52ms lowcarbon. 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. Hydrogen pressure, assisted by hydrogen embrittlement then can cause cracks to appear without the requirement for any external stresses. 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. 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. This process creates a high pressure and provides the basis for starting hydrogen induced cracks.
Failure to detect hic on time may lead to catastrophic failures. We will now go over how to prevent hic from happening. Hydrogeninduced cracking hic refers to the internal cracks brought about by material trapped in budding hydrogen atoms. Hydrogen induced cracking is a form of planar cracking when atomic hydrogen diffuses into the carbon or low alloy steel plate. 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. Also high strength structural steels which are welded are exposed to a certain hydrogen pickup which means a risk at fracture and blistering due to hic. Hydrogen induced cracking hic remains a prominent issue for oil and gas. Hydrogen sulphide cracking is one of the important processes in the oil and gas industry as the hydrocarbons that are produced contain considerable amounts of hydrogen sulphide. Unfortunately, all three phenomena reveal themselves in. A further challenge is that hydrogen absorption can happen at the same time as chloride stress corrosion cracking scc, which is another corrosion mechanism that is common at elevated temperatures. Sometimes, the structures of molecules in one fraction are rearranged to produce another. Hydrogen cracking its causes, costs and future occurrence. Steels with different microstructures were produced by a thermomechanically controlled process tmcp from two different heats. Hydrogen production 2 hydrogen diffusion 3 hydrogen trapping in defaults 4 increasing of pressure 5.
Initiation of stress corrosion cracking and hydrogeninduced. Hic usually occurs due to the effects of aqueous hydrogen charging of steel in wet h2s refinery process environments. Ansinace tm02842016, evaluation of pipeline and pressure. Hydrogeninduced cracking hic is a far too common type of failure. Processes or conditions involving wet hydrogen sulfide, i. This process is known as hydrogen embrittlement or hydrogeninduced cracking. There are some guidelines on materials requirements for carbon and low alloy steels for h 2 scontaining environments in oil and gas production. Preheat the base metal at the minimum of 200 f degrees and maintain the preheat temperature throughout the whole process. As a result, the metal becomes brittle and vulnerable to hydrogeninduced cracking hic, especially at low temperatures.
Corrosionpedia potential causes of corrosion in pre. The process was first used around 1942 and employs a powdered catalyst. Corrosion standard tests of carbon steels to be used in oil and gas production. Hydrogen induced cracking hic from advanced ndt solutions. Hydrogen induced cracking hic damage is a degradation mechanism active in the oil and gas industry.
Combatting the problem of hydrogen induced cracking in sour service, hic steel plate is carbon steel plates which are tested to assess the susceptibility of the material to hydrogen induced cracking. During wwii, the allied forces had plentiful supplies of the materials in contrast. Ultrasonic detection of hydrogen induced cracking hic in. Hydrogen cracking its causes, costs and future occurrence p h m hart weld metal hydrogen cracking in pipeline girth welds, proc.
The advantages and limitations for reallife industrial applications are, also, discussed. Considering that h 2 solubility increases with temperature, concentration and pressure, this makes hydrogeninduced cracking a big concern in precombustion hydrogen production process plants. As states above hydrogen come from high moisture content in atmosphere, welding consumables and joint. Hydrogen embrittlement he also known as hydrogen assisted cracking hac and hydrogeninduced cracking hic, describes the embrittling of metal after being exposed to hydrogen. When they are processed in the refineries, hydrogen sulphide gas h 2 s, which is a toxic gas is produced. Steel pipelines and pressurised equipment can operate satisfactorily for up to 8 to 10 years before any cracks are discovered. Hydrogen induced cracking hic occurs when carbon steel is exposed to hydrogen sulphide h 2 s and is the direct result of electrochemical corrosion reactions between the sour service or wet h 2 s environment. Hydrogen induced cracking hic in the oil and gas industry.