Jun 03, 2018 hydrogeninduced cracking hic refers to the internal cracks brought about by material trapped in budding hydrogen atoms. The hydrogen atom is the smallest of all atoms and hydrogen attack is similarly insidious and hidden from simple inspection techniques. Applying higher current densities resulted in severe pitting and microcracking, as well as oxygen contamination of the hydrogenattacked areas in both ti6al4v alloys. Hic test, hydrogen induced cracking test, step wise cracking. And yet, its poorly understood by most engineers and rarely accounted for. 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. Hydrogen induced cracking hic in the oil and gas industry. Preventing hydrogen induced cracking welding answers. Material and metallurgical parameters were investigated. 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. Temperature effects on hydrogeninduced cracking in an. Hydrogen embrittlement is generally observed at temperatures in the vicinity of room temperature, as the embrittlement requires that hydrogen have sufficient mobility to maintain a critical concentration at the advancing crack tip.
Corrosionpedia explains hydrogeninduced cracking hic the mechanism of hic begins with atoms of hydrogen diffusing throughout the material. The methane molecules create a pressure buildup in the metal lattice voids, which leads to embrittlement and even cracking of the metal. Published by welding technology institute of australia wtia, silverwater, nsw, australia, 1999. Experience has shown that stainless steels can suffer from hydrogen induced stress cracking hisc under cathodic protection in seawater. Weld metal hydrogen cracking in pipeline girth welds, proc. Hydrogen experts testing, consulting, and analysis by. Additionally, hydrogen atoms diffuse through metals and coalesce.
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. In the case of a crystal lattice becoming saturated or coming into contact with atomic hydrogen, many alloys and metals may. The difference between stresscorrosion cracking and hydrogen embrittlement stresscorrosion cracking scc and hydrogen embrittlement are differentiated by their responses to the applied current and mode of cracking. The methane accumulates at the grain boundaries and cannot diffuse through the metal resulting in high. Abstract as a first step, a literature survey was undertaken on hydrogen induced cracking hic phenomena. Factors influencing hydrogen induced cracking welding. At elevated temperatures, hydrogen tends to have increased solubility, allowing it to disperse into the material. Generally, the tendency toward hydrogen cracking decreases with increasing temperature.
Hydrogen embrittlement embrittlement is a phenomenon that causes loss of ductility in a material, thus making it brittle. A metallographic analysis of these steels was performed before and after nace tm0284 standard testing. Hydrogeninduced cracking an overview sciencedirect topics. Mechanisms that have been proposed to explain embrittlement include the formation of brittle hydrides, the creation of voids that can lead to bubbles and pressure buildup within a material and e.
High temperature hydrogen attack is also referred to as hot hydrogen attack or decarburization. Hydrogen induced cracking test apparatus is rectangular provided with ready to use connections fittings. Hydrogeninduced craking hic, also referred to as hydrogen stress cracking or static fatigue, is a typical form of hydrogen embrittlement. A comparative study of hydrogeninduced cracking resistances. It involves atomic hydrogen, which is the smallest atom, that diffuses into a metallic structure. Dec 21, 2016 hydrogen induced cracking hic there are a variety of forms of wet h2s cracking. The presence of hydrogen in the weld metal or haz may lead to a form of cracking known as hydrogen. Nov 14, 2014 the presence of hydrogen in the weld metal or haz may lead to a form of cracking known as hydrogen. Hydrogen induced craking hic, also referred to as hydrogen stress cracking or static fatigue, is a typical form of hydrogen embrittlement. Hic test, hydrogen induced cracking test, step wise. Hic usually occurs due to the effects of aqueous hydrogen charging of steel in wet h2s refinery process. Hughes 1880 note on some effects produced by the immersion of steel and iron wires in acidulated water. The use of low hydrogen rods h8 or less helps to prevent cracking.
The present work evaluates hydrogen induced cracking by performing an elaborate ebsd electron backscatter diffraction study in a steel with transformation induced plasticity tripassisted steel. Hydrogeninduced cracking results from atomic hydrogen being absorbed by solid metals. Wet hydrogen sulfide h2s cracking inspectioneering. 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 is a type of deterioration which can be linked to corrosion and corrosioncontrol processes.
Atomic hydrogen is dispersed throughout the weld material, making it weak in mechanical properties. The results from the testing indicated that 25% cr super duplex stainless steel was susceptible to hisc even at 150 0 c. Hydrogeninduced cracking also referred to as cold cracking, is caused by the diffusion of hydrogen in the crystal lattice of haz near the fusion boundary. Johnson 1875 on some remarkable changes produced in iron and steels by the action of hydrogen acids.
Hydrogen cracking in titaniumbased alloys request pdf. The most common forms of wet h 2 s cracking are hydrogen induced cracking hic, stressoriented hydrogen induced cracking sohic, and sulfide stress cracking ssc. Jul 29, 2019 what is hydrogen induced cracking the presence of hydrogen at high temperature and pressure can cause embrittlement of carbon steel and alloy steels. Hic test apparatus is supplied with essential spares for uninterrupted long term testing. Corrosion products were characterized by scanning electron microscopy and xray dispersive energy spectrometry, which were. What is hydrogen induced cracking the presence of hydrogen at high temperature and pressure can cause embrittlement of carbon steel and alloy steels. Hydrogen induced cracking hic is most commonly encountered in steels but other metals are susceptible, as shown in table 33. Hydrogen induced cracking steel features, applications. The threshold stresses to cause cracking are commonly below the yield stress of the material. Hic is often fairly innocuous but not always, while sohic is a type of cracking that can easily lead to failure. Incoloy 825 is superiorly immune to stainless steel grade 316 in the chloride media due to larger content of nickel. Hightemperature hydrogen attack is also referred to as hot hydrogen attack or decarburization. The most common forms of wet h 2 s cracking are hydrogen induced cracking hic, stressoriented hydrogen induced cracking sohic, and.
Factors influencing hydrogen induced cracking welding answers. Under hydrogen effect in titanium alloys, there are hydrogeninduced ductility loss hydrogen embrittlement and hydrogeninduced cracking occurs 7, 1415. O ur last post factors influencing hydrogen induced cracking went over the factors that contribute to hydrogeninduced cracking. High temperature hydrogen sulfide corrosion corrosion. The paper looks at the problem of hydrogen cracking both in general fabrication and with particular reference to. Said@ saudi aramco saudi arabia, dhahran, 311 abstract a saudi aramco gas processing plant commissioned in 1980 to process wet sour gas. At high temperature and high hydrogen partial pressure, hydrogen can diffuse into carbon steel alloys. Hydrogen embrittlement is the process by which various metals, most importantly highstrength steel, become brittle and fracture following exposure to hydrogen. Equivalently, low temperature hydrogen induced cracking was also noticed in inconel 718. The threshold pressures, p, of hydrogen and deuterium gases necessary to cause crack propagation in aisi 4340 steel of 250 ksi yield strength have. Hydrogen induced cracking of hard materials zthe refining industry has had very few cases of hydrogen related cracking in pure hydrogen service. Hydrogen induced cracking steel features, applications and. This form of cracking is also commonly referred to as hydrogen.
Sulfide stress cracking ssc is a form of hydrogen embrittlement which is a cathodic cracking mechanism. 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. Decarburisation caused by the reaction between carbon as carbide and dissolved hydrogen to form methane. In order to evaluate the resistance to hydrogeninduced cracking of pipeline and pressure vessel steel, standard test shall be conducted in accordance with nace tm0284. This type of steel exhibits a multiphase microstructure which undergoes a. This type of steel exhibits a multiphase microstructure which undergoes a deformation induced phase transformation. Before a wellbonded joint is produced, the joint surface is to be heated above the melting temperature in order to completely fuse with the weld metal. This micrograph shows intergranular cracking caused by high temperature hydrogen attack in a c0. Jun 05, 2017 generally, the tendency toward hydrogen cracking decreases with increasing temperature. Susceptibility to hydrogen induced cracking of api 5l b and x52ms lowcarbon steels in nace 177a, 177b, and 284b solutions has been investigated by the present work. Particularly common to the oil and gas industry where the use of steel. 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. The blistering damage tends to form parallel to the surface and to the direction of hoop stress.
Our last post factors influencing hydrogen induced cracking went over the factors that contribute to hydrogeninduced cracking. Cracking occurs due to a significant loss in ductility. High temperature hydrogen attack the damage mechanism that leads to htha is. Cold cracking is a hydrogen embrittlement phenomenon, often referred to as hydrogen induced cracking or haz cracking see 2. Hydrogen embrittlement failures are frequently unexpected and sometimes catastrophic. In susceptible alloys, the hydrogen combines with carbon within the alloy and forms methane. Hydrogen induced cracking hic on steel for corrosion. The alloy microstructure second phases, precipitates, inclusions, carbides etc. Hydrogen induced cracking hic assessment in a gas processing plant case study mohammed a abufour, mohammad. Hic usually occurs due to the effects of aqueous hydrogen charging of steel in wet h2s refinery process environments. Cosasco provides hydrogen monitoring solutions for corrosion control such as hydrogen blistering hydrogen induced cracking hic on steel. Vargas pm, wastberg s and woollin p, stress based design guidelines for hydrogen induced stress cracking hisc avoidance in duplex materials, proc conf omae 200979504. Atomic hydrogen is able to permeate into steel and reacts with iron carbides to form methane.
It occurs in carbon and lowalloyed steels exposed for an extended period to hydrogen under high pressure and at high temperature. Hydrogeninduced cracking occurs when the crystal lattice of an alloy becomes saturated with diffuse hydrogen atoms. This can occur during elevatedtemperature thermal treatments and in service during electroplating, contact with maintenance chemicals, wet h 2 s, corrosion reactions, cathodic protection, and operating in highpressure hydrogencontaining environments. Dissolution of hydrogen from the process environment. The threshold pressures, p, of hydrogen and deuterium gases necessary to cause crack propagation in aisi 4340 steel of 250 ksi yield strength have been determined as functions of planestrain stress. May 19, 2009 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. It is well documented that hydrogen concentration, temperature, stress state and yield strength have a strong effect on hydrogeninduced thresholds. It is a complex process that is not completely understood because of the variety and complexity of mechanisms that can lead to embrittlement. Hydrogen cracking its causes, costs and future occurrence. Hydrogeninduced cracking hic is a far too common type of failure.
This can occur during elevated temperature thermal treatments and in service during electroplating, contact with maintenance chemicals, wet h 2 s, corrosion reactions, cathodic protection, and operating in highpressure hydrogencontaining environments. Hydrogen induced stress cracking, seawater, cathodic protection, elevated temperature, duplex. Hydrogeninduced cracking susceptibility in highstrength. Hydrogen induced cracking hic damage is a degradation mechanism active in the oil and gas industry. We will now go over how to prevent hic from happening. Arc welding is a process by which steels are joined by coalescence. Below 20f 7c the diffusion rate of the hydrogen is so slow that. It is characterized by the brittle fracture of a normally ductile alloy under sustained load in the presence of hydrogen. Hydrogeninduced cracking hic is most commonly encountered in steels but other metals are susceptible, as shown in table 33. Stress corrosion cracking behavior of nickel base alloys. Susceptible alloys, especially steels, react with hydrogen sulfide, forming metal sulfides and atomic hydrogen as corrosion byproducts. However, bp and shell experience some serious cracking of duplex steel in the mid 90ties and in beginning of the century. The root cause of these failures was identified to be hydrogen induced stress cracking, hisc, where the hydrogen source was the.
If using smaw process, the weldment after completion of welding must be maintained to about 500 f 260 c degrees for about two hours without allowing it to cool down to specified minimum preheat temperature. Hydrogen induced cracking hic from advanced ndt solutions. The presence of hydrogen in the weld metal or haz may lead to a form of cracking known as hydrogeninduced cracking hic. The hydrogeninduced cracking hic susceptibility of weld met als of hightensile strength ranging from 70 to 100 kgfmm2 100 to 143 ksi was investigated to estimate the lowest possi ble preheat and interpass temperatures to prevent cracking. It should not be confused with the term stress corrosion cracking which is an anodic cracking mechanism. Hydrogen embrittlement and stress corrosion cracking. Hydrogen induced cracking of subsea duplex stainless steel twi. Hydrogen induced stress cracking of superduplex steels. Welding of carbon and low alloy steels and hydrogen induced cracking. An externally applied load is not required as the tensile stresses may be due to residual stresses in the material. Hydrogen embrittlement is often the result of unintentional introduction of hydrogen into susceptible metals during forming or finishing operations. The ssrt results from hydrogen charged specimens were compared to specimens tested in air no hydrogen charging. Normally the process uses a compatible filler material.
Hydrogen embrittlement an overview sciencedirect topics. High temperature hydrogen sulfide corrosion of carbon steel and low chrome alloys has become a serious problem in the petroleum industry in connection with the increasing use of high pressure hydrogenation and dehydrogenation processes for upgrading petroleum fractions. The steel specimens shall be immersed into test solutions at the temperature 253c 775f. When tensile stresses are applied to a hydrogen embrittled component it may fail prematurely. 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. Corrosionpedia what is hydrogeninduced cracking hic. Hydrogeninduced cracking hic refers to the internal cracks brought about by material trapped in budding hydrogen atoms. Welding of carbon and low alloy steels and hydrogen. Sep 07, 2009 sulfide stress cracking is most severe at ambient temperature, 20 to 120f 7 to 49c. If you recall, we mentioned you need all three factors to be present in order to have hic.
The presence of hydrogen atoms in a metal degrades some of its mechanical properties, especially its ductility, leading in some cases to embrittlement. Efc publication 17, 2nd edition, corrosion resistant alloys for oil and gas production. G2mt labs provides unparalleled expertise in hydrogen testing, consulting, and analysis from hightemperature hydrogen attack to embrittlement, hydrogen plays a critical role in the life, and often the failure, of many metals. Hic test specimens are machined with thickness of 530mm, width 20mm, and length of 100mm is suitable for testing as per the nace standard. 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. However, in cases where greater than the critical concentration is already present, e. This typically occurs at higher rates in extreme temperatures, given the proportional relationship between the solubility and temperature of hydrogen.
1015 659 500 1005 1169 113 603 376 684 1187 11 1213 1436 974 1318 1497 1180 814 774 775 276 1284 712 574 487 601 457 479 1540 219 1269 122 1174 840 224 1313 1018 824 878 390 1379 962