Factors influencing hydrogen induced cracking welding. To mitigate the risk of caustic scc, all cs welds and coldformed. Hydrogen induced cracking steel features, applications and. Present work aims to highlight the critical nature of these hydrogen induced blister cracking on the mechanical property degradation of api 5l x65 steel. Corrosion standard tests of carbon steels to be used in oil and gas production. In petrochemistry, petroleum geology and organic chemistry, cracking is the process whereby complex organic molecules such as kerogens or longchain hydrocarbons are broken down into simpler molecules such as light hydrocarbons, by the breaking of carboncarbon bonds in the precursors. Hydrogen induced cracking of low strength steels in. Fractographic and microstructural observations provide evidences of delayed hydrogen induced cracking. A metallographic analysis of these steels was performed before and after nace tm0284 standard testing. Processes or conditions involving wet hydrogen sulfide, i. Fractographic and microstructural observations provide evidences of delayed hydrogeninduced cracking.
I have always thought by now that hydrogen may work as a stress raiser additionally or subsequently to a martensite formation and thus hydrogen induced cold cracking can take place as the worst case. A comparative study of hydrogeninduced cracking resistances. Slow cooling of hot rolled bars to eliminate hydrogen induced. Hydrogen induced cracking steel features, applications. This phenomenon usually occurs only with highstrength, hard. Cosasco provides hydrogen monitoring solutions for corrosion control such as hydrogen blistering hydrogen induced cracking hic on steel. Also called hydrogen assisted cracking or hydrogen cracking, it infests either the weld zone or the heat affected zone haz. Introduction the problem of hydrogen induced cold cracking in quenched and tem pered low alloy steels is unlikely to be resolved without a greater under standing of both the location and the mechanism of crack initiation and the metallurgical response of the. Johnson university of illinois at urbanachampaign 216 talbot laboratory 104 south wright street urbana, il 61801. Particularly common to the oil and gas industry where the use of steel.
Involves the penetration of hydrogen, which results in enhancing brittleness and decreasing tensile strength. This is a type of deterioration which can be linked to corrosion and corrosioncontrol processes. Hydrogeninduced cracking in surface production systems. The trapped molecular hydrogen in the mill laminations or voids will have high internal pressure which will cause hydrogen blistering or cracking. Hydrogen cracking may also be called cold cracking or delayed cracking. Sour service is a environment containing water and h2s hydrogen sulfide with pressure of 50ppm if the presence of hydrogen sulfide i. Susceptibility to hydrogeninduced cracking of api 5l b and x52ms lowcarbon. Such a void can provide a space for the hydrogen atoms to form hydrogen gas. This penetration can lead to the brittle fracture of materials that are normally ductile when hydrogen happens to be present in their environment. The equilibrium pressure of molecular hydrogen in contact with atomic hydrogen is sufficient enough to rupture any material. Typical combustion engines, whether burning hydrogen or petroleum are 25% efficient at a maximum. If steel is in a hydrogen environment of high temperature and pressure, hydrogen attack can occur. With the signing of a contract on the use of cold cracking technology in china, an important breakthrough in the field of heavy oil production and. Hydrogen embrittlement he also known as hydrogen assisted cracking hac and hydrogeninduced cracking hic, describes the embrittling of metal after being exposed to hydrogen.
The blistering damage tends to form parallel to the surface and to the direction of hoop stress. The consequences of cracks formed on the oil and gas pipelines. Highly restrained joints can contribute to hydrogeninduced cracking because they are already naturally under stress, which can compound the other stresses caused by hydrogen in the weld and lead to cracking. Hic in welding cold cracking haz cracking moisture n org compounds r primary sources of h. Hydrogen induced cracking comes into effect as a synergy of hydrogen concentration and stress level on susceptible steel materials, leading to severe hydrogen embrittlement he scenarios. 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. May 19, 2009 susceptibility to hydrogen blistering and hydrogen induced cracking can be apportioned to the quality of the steel plate used.
Jun 05, 2017 hydrogen damage can be classified into four types. Klas weman, in welding processes handbook second edition, 2012. Jun 03, 2018 hydrogeninduced cracking hic refers to the internal cracks brought about by material trapped in budding hydrogen atoms. Hydrogen induced cracking hic or hydrogen pressure induced cracking hpic apart from its general meaning, this is a jargon term referring to a specific morphology of cracking occurring in steel pipelines and vessels which absorb hydrogen during service. Hydrogen induced cold cracking in a low alloy steel. Such stress states can be caused both by the presence of residual stresses, associated fabrication. Our last post factors influencing hydrogen induced cracking went over the factors that contribute to hydrogeninduced cracking. Cold cracks are formed along the weld and fusion line, as a rule, after welding, during. Pdf according to the latest survey literature on destructive factors of steel pipelines, hydrogen induced cracking has been recognized as a. Hi all, i was reading one of the articles on hydrogen induced cold cracking in steels. 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 embrittlement is also referred to as hydrogen cracking or cold cracking.
Has anybody of you ever heard of hydrogen induced martensite formation. They are also known as cold, delayed or underbead toe cracking. Because this cracking occurs after the steel has cooled below approximately 400f, it can be called cold cracking, and because it is associated with hydrogen, it is also called hydrogen assisted cracking. Actually, trapped hydrogen can cause cracking in the entire vessel, but lets focus. Recent experience has demonstrated the risk of sscc and hic, sometimes known as hydrogen embrittlement he, of low strength steels subject to high residual stress derived from fabrication techniques. Embrittlement hydrogen induced cracking and hydrogen embrittlement cracking causes failure at stresses well below the yield strength. Hydrogeninduced cracks occur primarily in the grain coarsened region of the h. 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. The cracks occur in the haz, close to the melt boundary as the material cools, sometimes several hours after welding. Pdf the consequences of cracks formed on the oil and gas.
Because molecular hydrogen cannot diffuse, tremendous pressure builds up inside these voids. Sep 07, 2009 the methane molecules create a pressure which leads to embrittlement and even cracking of the metal. Another type of hydrogen corrosion, stressorientated hydrogen induced cracking sochic, is normally found in the base metal adjacent to the weld, where the stress point is highest due to the internal pressure of the. Hydrogen induced blister cracking and mechanical failure. Hydrogeninduced cracking an overview sciencedirect topics. This barcode number lets you verify that youre getting exactly the right version or edition of a book. Hydrogen induced cracking hic is a failure mechanism resulting in sudden exposures and cracks due to growing laminations inside the base material and welds. Factors influencing hydrogen induced cracking welding answers.
A comparative study of hydrogeninduced cracking resistances of. If you recall, we mentioned you need all three factors to be present in order to have hic. Hydrogeninduced cracking hic or hydrogen pressureinduced cracking hpic. It involves atomic hydrogen, which is the smallest atom, that diffuses into a metallic structure.
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. We will now go over how to prevent hic from happening. Hydrogen stress cracking is a form of hydrogen embrittlement that occurs when corrosion from acids like wet hydrogen sulfide and hydrofluoric acid cause atomic hydrogen to penetrate hardened or higher strength steels and cause stress cracking. The methane molecules create a pressure which leads to embrittlement and even cracking of the metal. Hydrogen cracking its causes, costs and future occurrence. 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. Pipelines and piping systems which contain petroleum, petroleum products, or fuel gases that may be pressurized andor flowing. Hydrogen embrittlement and stress corrosion cracking. 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. Hic test, hydrogen induced cracking test, step wise. There are three factors which combine to cause cracking.
Has anybody of you ever heard of hydrogeninduced martensite formation. In petrochemistry, petroleum geology and organic chemistry, cracking is the process whereby. 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. If steel is in a hydrogen environment of high temperature and. Steels treated with rare earth metals also exhibit a low hic caused by the. Hydrogen cracking its causes, costs and future occurrence p h m hart weld metal hydrogen cracking in pipeline girth welds, proc. When welding stronger steel materials, hydrogen assisted cold cracking hacc is a real problem. Ep1435399b1 ep03250056a ep03250056a ep1435399b1 ep 1435399 b1 ep1435399 b1 ep 1435399b1 ep 03250056 a ep03250056 a ep 03250056a ep 03250056 a ep03250056 a ep 03250056a ep 1435399 b1 ep1435399 b1 ep 1435399b1 authority ep european patent office prior art keywords weld metal welding weld welding method pcm prior art date 20030102 legal status the legal status is an. Avoid burning through where the welding arc causes the pipe wall to be breached. In this issue, the characteristic features and principal causes of hydrogen cracks are described. In the presence of h 2 s, hydrogen atoms originating from the cathodic reduction reaction driving the anodic dissolution reaction can diffuse into the steel, resulting in cracking mechanisms such as hydrogeninduced cracking hic, sulphide stress cracking ssc and stressoriented hydrogeninduced cracking sohic. General requirements for the purchase of pipes for use in oil and gas industries. 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. It lies parallel to the fusion boundary and its path is usually a combination of inter and transgranular cracking.
Pressure builds and blisters form resulting in rupture and leakage. Hydrogen embrittlement also known as hydrogen assisted cracking and hydrogeninduced cracking, describes the embrittling of metal after being exposed to hydrogen. Cracking occurs due to a significant loss in ductility. Hydrogeninduced cracking hic is a far too common type of failure. Hydrogen sulfide is often encountered in the petroleum industryduring the drilling and completion of oil and gas wells, and during the storage and piping of petroleum products containing hydrogen sulfide. 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. Defects hydrogen cracks in steels identification twi. 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. Investigation of oil and natural gas pipelines failure by hydrogen. Weld cracking several types of discontinuities may occur in welds or.
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. In order for heat affected zone cracking to occur, three. Cracking usually occurs at temperatures at or near normal ambient. Corrosionpedia what is hydrogeninduced cracking hic. Many process streams in petroleum refineries with an aqueous phase contain enough hydrogen sulfide to cause corrosion or cracking in susceptible. Unlike a hydrotreater, hydrocracking uses hydrogen to break cc bonds. Hic usually occurs due to the effects of aqueous hydrogen charging of steel in wet h2s refinery process environments. Steels used to construct sour gas production facilities and flowlines may corrode from wet hydrogen sulfide gas in the production stream. Common causes and cures of hydrogen cracking fabricating. Hydrogen induced cracking hic on steel for corrosion. Pdf due to population growth, the need of petroleum products has.
Butt welds exhibit transverse cracks while fillet welds have longitudinal ones. The beneficial microstructure for avoiding the transverse cracks was. Hydrogeninduced cracking is also known as cold cracking, delayed cracking or. Hydrogen induced cracking hic is a materials and corrosion related problem that occurs in surface production systems. Ep1435399b1 a welding method for improving resistance to. Hydrogen induced blister cracking and mechanical failure in. It is a complex process that is not completely understood because of the variety and complexity of mechanisms that can lead to embrittlement.
I have always thought by now that hydrogen may work as a stress raiser additionally or subsequently to a martensite formation and thus hydrogeninduced cold cracking can take place as. Atomic hydrogen diffuses inside the metal and causes localized deformation, or even destroys the walls of the vessel. Hydrogen embrittlement an overview sciencedirect topics. The present work is organized in three parts, firstly, the role of microstructural constituents on hydrogen induced cracking and blister formation is discussed. Current fuel cells are roughly 60% efficient, though when heat trapping features are included, they can reach 83% efficiency. Hydrogen induced cracking test instrument is supplied with standard size of 12l x 12w x 9h. 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. 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. Hydrogen induced cracking of hard materials zthe refining industry has had very few cases of hydrogen related cracking in pure hydrogen service. Slow cooling of hot rolled bars to eliminate hydrogen.
Preventing hydrogen induced cracking welding answers. Control of this cracking requires the use of lowhydrogen electrodes, high. Doe hydrogen program fy 2005 progress report 421 v. Hic testing apparatus is provided with specially made rack to keep the samples with minimum surface contact and all the specimens can be viewed during the test period easily.
Atomic hydrogen is dispersed throughout the weld material, making it weak in mechanical properties. 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 blistering is one of the forms of corrosion and is dominant in the petroleum industry. Corrosion products were characterized by scanning electron microscopy and xray dispersive energy spectrometry, which were. Burning hydrogen is a less efficient means of extracting energy than are hydrogen fuel cells. Hydrogeninduced cracking hic refers to the internal cracks brought about by material trapped in budding hydrogen atoms. Fabrication practices to mitigate risks of refinery corrosion cracking. The rate of cracking and the end products are strongly dependent on the temperature and presence of catalysts. Hacc is characterized by cracks that form in the weld andor heat affected zone of the base metal once the weldment reduces temperature.