A detailed assessment study was conducted in this plant pertaining to hydrogen induced cracking hic. Hydrogeninduced cracking hic is still a challenging issue that requires. Johnson 1875 on some remarkable changes produced in iron and steels by the action of hydrogen acids. 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. S service in elevated pressure and temperature profiles. Considering that h 2 solubility increases with temperature, concentration and pressure, this makes hydrogeninduced cracking a big concern in precombustion hydrogen production process plants. It involves atomic hydrogen, which is the smallest atom, that diffuses into a metallic structure. 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. Initiation of stress corrosion cracking and hydrogeninduced cracking in oil and gas. Generally, hic susceptibility is evaluated after the test duration, typically 96 h, in accordance with nace standard tm02842016.
We will now go over how to prevent hic from happening. Hydrogen embrittlement he also known as hydrogen assisted cracking hac and. 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. Hydrogen blistering a special case of hydrogen damage is known as hydrogen blistering. Hydrogen cracking may also be called cold cracking or delayed cracking. The process was first used around 1942 and employs a powdered catalyst. This pressure will rise with time and cause reduction in the metals ductility and tensile strength, leading to hydrogeninduced cracking hic. Sulfide stress cracking ssc vs hydrogen induced cracking hlc posted in refining, hydrocarbons, oil, and gas. Hydrogen induced cracking of pipeline and pressure vessel.
The degradation of structural integrity in the presence of hic may advance slowly or rapidly depending on the operational conditions. 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. Wet h2s service what are the requirements for steel plate. Initiation of stress corrosion cracking and hydrogen. This is a problem commonly found in wet h2ssour service operating environments such as in the oil, gas and petrochemical industry. Hic usually occurs due to the effects of aqueous hydrogen charging of steel in wet h2s refinery process environments.
Analysis of hydrogen induced cracking by insitu hic observation. This is a type of deterioration which can be linked to corrosion and corrosioncontrol processes. The advantages and limitations for reallife industrial applications are, also, discussed. 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. Examples of internal hydrogen embrittlement include processes such as. During wwii, the allied forces had plentiful supplies of the materials in contrast. Sometimes, the structures of molecules in one fraction are rearranged to produce another. Corrosion products were characterized by scanning electron microscopy and xray dispersive. 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. 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. Hydrogen induced cracking steel features, applications. The blistering damage tends to form parallel to the surface and to the direction of hoop stress.
If you recall, we mentioned you need all three factors to be present in order to have hic. Mechanism of cracking in the presence of h2s, the process of cracking hic can be divided in to 5 stages 1 corrosion. O ur last post factors influencing hydrogen induced cracking went over the factors that contribute to hydrogeninduced cracking. Hydrogeninduced 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 h 2 scontaining environments in oil and gas production. Commonly, this is done using a process called alkylation. Hydrogen cracking its causes, costs and future occurrence. 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. Hydrogen sulphide gas is a poisonous gas and cannot be emitted into the environment without treatment, thus hydrogen sulphide cracking process has. Hydrogeninduced cracking hic is a far too common type of failure. Hydrogeninduced cracking an overview sciencedirect topics. Initiation of stress corrosion cracking and hydrogeninduced. 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. Regarding applications in the oil and gas industry, hydrogeninduced cracking can occur on a very wide variety of steel equipment.
Over time, hydrogen collects in these areas and builds stress that, in some cases, is high enough that hydrogeninduced cracking occurs. 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. However, it may take longer for the cracks to grow. 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. A comparative study of hydrogeninduced cracking resistances of. Common causes and cures of hydrogen cracking fabricating. Hydrogen induced cracking hic remains a prominent issue for oil and gas. Hydrogeninduced cracking hic refers to the internal cracks brought about by material trapped in budding hydrogen atoms. The hydrogen deleterious effect has a relevant industrial and economic impact being, at the same time, a challenge from the scientific point of view. Hydrogen pressure, assisted by hydrogen embrittlement then can cause cracks to appear without the requirement for any external stresses. The hydrogen atom is the smallest of all atoms and hydrogen attack is similarly insidious and hidden from simple inspection techniques. Corrosionpedia potential causes of corrosion in pre. Guidelines for production of api pipelines steels suitable.
Steel pipelines and pressurised equipment can operate satisfactorily for up to 8 to 10 years before any cracks are discovered. Hydrogen induced cracking is a form of planar cracking when atomic hydrogen diffuses into the carbon or low alloy steel plate. Cracking occurs due to a significant loss in ductility. When they are processed in the refineries, hydrogen sulphide gas h 2 s, which is a toxic gas is produced. Susceptibility to hydrogeninduced cracking of api 5l b and x52ms lowcarbon. These internal cracks may propagate by a process called hydrogeninduced cracking hic or hydrogen blistering.
Steels with different microstructures were produced by a thermomechanically controlled process tmcp from two different heats. The factors influencing the occurrence of hydrogeninduced cracking hic in steel plates have been investigated by means of ultrasonic cscanning of. Effect of microstructure on hydrogeninduced cracking of. Hic can be prevented, or even reversed, through several process which focus on ensuring that no contact is made between the metal and hydrogen. Corrosion standard tests of carbon steels to be used in oil and gas production. 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. Hydrogeninduced cracking hic has been studied phenomenologically. 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.
This process is known as hydrogen embrittlement or hydrogeninduced cracking. Chemical processing how oil refining works howstuffworks. 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. As we know that both form of cracking are due to the absorption of atomic hydrogen that. Ultrasonic detection of hydrogen induced cracking hic in. Preventing hydrogen induced cracking welding answers. Handbook of materials failure analysis with case studies from the oil and gas. As a result, the metal becomes brittle and vulnerable to hydrogeninduced cracking hic, especially at low temperatures. Failure to detect hic on time may lead to catastrophic failures.
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. 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. 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. Summary hydrogen induced cracking hic is a materials and corrosion related. Unfortunately, all three phenomena reveal themselves in. Since not all aspects of the corrosion process of steel in sour gas. 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. Hic steel hydrogen induced cracking supplier company. A process is provided for treating crude oil to visbreak andor upgrade such oil using hydrogen gas. 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. Thorough cleaning of weld joint at least 25mm on either side, inside and outside if joining a pipe removes grease, oil, coatings, water etc.
No external stress on test specimens is usually required to examine this type of cracking. Abstract hydrogeninduced cracking hic has been studied phenomenologically. Ansinace tm02842016, evaluation of pipeline and pressure. Hughes 1880 note on some effects produced by the immersion of steel and iron wires in acidulated water.
The process includes the steps of introducing hydrogen into a heated stream of crude oil or partially upgraded crude oil and mixing such introduced hydrogen with the oil to achieve intimate dispersion of hydrogen to enhance thereby visbreaking andor upgrading. Factors influencing hydrogen induced cracking welding. 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. Corrosion loops were established for the sour environment and. In the case of a crystal lattice becoming saturated. Common causes and cures of hydrogen cracking knowing the means by which hydrogen can enter the weld is a good defense against potential problems. 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. To understand better the mechanism of the crack initiation process, key. Processes or conditions involving wet hydrogen sulfide, i. Hydrogeninduced cracking in surface production systems. Investigation of oil and natural gas pipelines failure by hydrogen. Defects hydrogen cracks in steels identification twi.
Hydrogen induced cracking hic in the oil and gas industry. Hydrogen induced cracking hic is a failure mechanism resulting in sudden exposures and cracks due to growing laminations inside the base material and welds. Abstract hydrogen induced cracking hic is one of the major issues of line. Hydrogen cracking its causes, costs and future occurrence p h m hart weld metal hydrogen cracking in pipeline girth welds, proc. Hydrogeninduced cracking can also occur in the weld metal itself and when it does, it is typically transverse to the weld direction. 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. This process creates a high pressure and provides the basis for starting hydrogen induced cracks. 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. Sulfide stress cracking ssc vs hydrogen induced cracking. Preheat the base metal at the minimum of 200 f degrees and maintain the preheat temperature throughout the whole process. Hydrogen production 2 hydrogen diffusion 3 hydrogen trapping in defaults 4 increasing of pressure 5. Detail hobart brothers performance welding products. Hydrogen which is produced at cathode due to corrosion reaction, diffuses into the steel and result in cracking in wet hydrogen sulfide environment. Hydrogen induced cracking hic from advanced ndt solutions.
Corrosionpedia what is hydrogeninduced cracking hic. 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. The effect of microstructure on hic is discussed for steels having two different levels of nonmetallic inclusions. A metallographic analysis of these steels was performed before and after nace tm0284 standard testing. It is a complex process that is not completely understood because of the variety and complexity of mechanisms that can lead to embrittlement.
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