Corrosion problems during oil and gas production and its. The understanding of cracking mechanism is complex since there are various factors that can initiate and propagate crack events. The letter in conjunction with the number designates parameters such as the maximum yield strength and the minimum ultimate strength which for l80 pipe are 95,000 psi. Sulfide stress cracking is the cracking of a metal under the combined action of tensile stress and corrosion in the presence of water and hydrogen sulfide a. Hydrogen electrode reaction and hydrogen embrittlement of mild steel in hydrogen sulfide solutions. Sulfide stress corrosion cracking and hydrogen induced cracking of a216wcc wellhead flow control valve body article pdf available in case studies in engineering failure analysis. Sulfide stress cracking ssc definition sulfide stress cracking ssc is a type of hydrogen cracking which presents a cathodic embrittlement mechanism. Hydrogen induced cracking hic is a form of tiny blistering damage caused by a high concentration of hydrogen in steel.
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. The mechanism of sulfide stress cracking involves a combination of stress corrosion cracking and hydrogen embrittlement. Dec 19, 2019 sulfide stress cracking ssc is a type of hydrogen cracking which presents a cathodic embrittlement mechanism. For example, copper and its alloys are susceptible to ammonia compounds, mild steels are susceptible to alkalis and stainless steels are susceptible to chlorides. The most common forms of wet h 2 s cracking are hydrogen induced cracking hic, stress oriented hydrogen induced cracking sohic, and sulfide stress cracking ssc. Is sulfide stress cracking an anodic or a cathodic process.
The obtained results indicate that the hydrogen sulfide is the most active gas in the corrosion processes that took place, quite above carbon dioxide. Element sulfide stress cracking ssc testing according the nace tm0177 iso. Sulphide stress cracking caused by the combined action of h 2 s corrosion and hydrogen. Hydrogen electrode reaction and hydrogen embrittlement of. This paper summarizes the main theories of stress corrosion cracking and corrosion fatigue and its latest developments, and it also points out that existing stress corrosion cracking theories can be reduced to the. Their geometry is such that if they grow to appropriate lengths they may reach a critical size that results in a transition from the relatively slow crack growth rates associated with stress corrosion to the fast crack propagation rates associated with purely mechanical failure. This condition can lead to embrittlement of the material, resulting in cracking under the combined action of tensile stress and corrosion. This is because insp 2 is linked to 581 sulfide stress cracking, which belongs to the same dme as 581amine cracking i.
Basics of sulfide stress cracking ssc and stress corrosion cracking scc ssc and scc are cracking processes that develop in the presence of water, corrosion and surface tensile stress. Sulfide stress cracking is the cracking of a metal under the combined action of tensile stress and corrosion in the presence of water and hydrogen sulfide a form of hydrogen stress cracking. Sulfide stress cracking ssc is a type of hydrogen cracking which presents a cathodic embrittlement mechanism. Modeling and experimental insights of sulfide stress. Strain and sulfide stress cracking in pipeline girth welds. Sulfide stress cracking nace mr01752002, mr0175iso. Basically the failure mechanism of ssc includes an initiation step and a propagation step of a crack. Corrosion failure, especially stress corrosion cracking and corrosion fatigue, is the main cause of centrifugal compressor impeller failure. A tentative ranking of the alloys has been established on the basis of the threshold stress values obtained from the tests conducted. The effect of cold work and strain ageing on the sulfide stress cracking resistance and mechanical properties of expanded tubular steels a laboratory study. Corrosionpedia what is sulfide stress cracking ssc.
It is the gradual destruction of materials usually a metal by chemical andor electrochemical reaction with their environment. Jan 31, 2016 hydrogen stress cracking hsc, defined as the cracking of a metal under the combined action of tensile stress and corrosion in the presence of water and nascent h, is exacerbated by applied cathodic potentials, figure 1 right. Their geometry is such that if they grow to appropriate lengths they may reach a critical size that results in a transition from the relatively slow crack. Corrosionpedia what are sulfatereducing bacteria srb. This paper summarizes the main theories of stress corrosion cracking and corrosion fatigue and its latest developments, and it also points out that existing stress corrosion cracking theories can be reduced to. Hic usually occurs due to the effects of aqueous hydrogen charging of steel in wet h2s refinery process. Sulfide stress cracking nace mr01752002, mr0175iso 15156. Thorough understanding of scc mechanisms of dss in chloride and hydrogen sulfide containing solutions has been useful for material selection in many. Susceptible alloys, especially steels, react with hydrogen sulfide, forming metal sulfides and atomic hydrogen as corrosion byproducts. Wet h 2 s cracking can occur in susceptible steels exposed to aqueous environments containing hydrogen sulfide. Sulfide stress corrosion cracking, also known as sulfide stress cracking ssc, is a stress corrosion cracking phenomena that occurs in the presence of hydrogen sulfide. The first type is commonly referred to as hydrogen induced cracking hic and can occur where little or no applied or residual tensile stress exists. Experimental results, polarization curves for the systems tested, and sulfur adsorption measurements on iron provide preliminary information on the mechanism of the joint action of organic compounds and hydrogen sulfide on iron corrosion in acid media.
It is a form of hydrogenrelated cracking and can have two distinct morphologies. Joint action of hydrogen sulfide and organic compounds on. The presence of flaws that concentrate stress or crevices that alter. Inhibitors had been shown to be one of the major tools for tackling corrosion in the oil and gas industries. Mechanism of sulfide corrosion hydrogen sulfide corrosion can occur by two mechanisms.
This is because insp 3 is linked to amine cracking ascc, which belongs to a related dme i. Action of corrosion and stress on % cr stainless steel. This combined action of hydrogen embrittlement and hydrogen sulfide. Sulfide stress cracking is a form of hydrogen embrittlement that occurs in highstrength steels and in localized hard zones in weldment of susceptible materials. Ricker, national institute of standards and technology stresscorrosion cracking scc is a term used to describe service failures in engineering materials that occur by slow, environmentally induced crack propagation. Transverse sections of steels showing ssc cracks, after corrosion testing according to nace tm017796 method a standard in 5. H2s can cause sulfide stress cracking of stainless steels. This term should not be confused with stress corrosion cracking scs, since this is anodic in nature. Selenium sulfide may act by an antimitotic action, resulting in a reduction in the turnover of epidermal cells. The effects of sulfide stress cracking on the mechanical properties. Sulfide stress cracking nace mr01752002, mr0175iso 15156 651 te c h n i c a l new sulfide stress cracking standard for refineries don bush, principal engineer materials, at emerson process management fisher valves, is a member and former chair of a nace task group that has written a document for refinery applications, nace mr0103. Stress corrosion cracking facts and how to reduce the risk.
Hydrogen sulfide is particularly dangerous to equipment when moisture is present. Microbial corrosion, also called bacterial corrosion, biocorrosion. It is a progressive type of failure that produces cracking at stress levels that are well below the materials tensile strength. Mechanism of stress corrosion cracking of steels in h 2 s. The tensile stress can be the residual stress in a fabricated structure, the hoop stress in a pipe containing fluid at pressures above ambient or in a vessel by virtue of the. However, the time required for crack initia tion is strongly dependent on a wide variety of pa rameters, such as surface finish. Sulfide stress crackingnace mr01752002, mr0175iso 15156 651 te c h n i c a l new sulfide stress cracking standard for refineries don bush, principal engineer materials, at emerson process management fisher valves, is a member and former chair of a nace task group that has written a document for refinery applications, nace mr0103. If an rbi analysis is linked to a 581amine cracking degradation mechanism. Stress corrosion cracking is the cracking of a susceptible metal under the mixed influence of a tensile stress either residual or applied in a corrosive environment 46. Sulfide stress cracking is a form of hydrogen embrittlement that occurs in highstrength steels and in localized hard zones in weldment of susceptible. Sulfide stress cracking, modeling mechanism, octg martensitic pipes, kinetic of crack propagation, trapped and diffusible hydrogen overview quenched and tempered martensitic steels for oil country tubular goods can be subject to sulfide stress cracking when exposed to a sour environment. Asahi kawashima, koji hashimoto, saburo shimodaira, hydrogen electrode reaction and hydrogen embrittlement of mild steel in hydrogen sulfide solutions, corrosion.
The major hazards of h 2 s are its ability to cause rapid damage to health or sudden death due to accidental exposure and metal integrity failure due to general corrosion or cracking. In that article, we concluded that while localized corrosion appears to be a prerequisite for anodic eac modes such as stress corrosion cracking scc, hydrogenassisted eac mechanisms like hydrogen stress cracking hsc are exacerbated at cathodic potentials. Review on stress corrosion and corrosion fatigue failure. The effect of strain on the susceptibility of pipeline girth welds to sulfide stress cracking. The use of material susceptible to stress corrosion cracking scc. Wet hydrogen sulfide h2s cracking inspectioneering. The mechanical properties and microstructure exhibited by the alloy after corrosion testing indicated that it could resist stress corrosion cracking, galvanically induced hydrogen stress cracking, and sulfide stress cracking. Pdf sulfide stress corrosion cracking and hydrogen induced. The sulfide corrosion of the chemical equipment is mainly caused by chemical corrosion, hydrogen drum, sulfide stress corrosion cracking and high temperature sulfur corrosion. Although it is not possible to completely rule out a fabrication hydrogen cracking mechanism in specimen scc8, this would not be expected with the procedure used, and no cracks were evident in any of the other untested metallographic. Strain and sulfide stress cracking in pipeline girth welds twi. Quenched and tempered martensitic steels for oil country tubular goods can be subject to sulfide stress cracking when exposed to a sour environment. This is because insp 2 is linked to 581sulfide stress cracking, which belongs to the same dme as 581amine cracking i.
As a form of hydrogen stress cracking, ssc is a cracking mechanism in. Sour gas cracking, also known as sulfide stress cracking ssc, is the deterioration of metal due to contact with hydrogen sulfide h 2 s and moisture. Scc can be attributed to the action of three important factors. 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.
Some sulfatereducing bacteria produce hydrogen sulfide, which can cause sulfide stress cracking. Sulfide stress cracking ssc was first identified and the mechanism outlined in the. Effects of strain rate, applied potential, ph, temperature, and hydrogen sulfide concentration on sulfide cracking of mild steel were examined at constant strain rates by means of an instrontype machine. Hydrogen sulfide is known to cause or assist in the mechanism of cracking with many alloy types including low carbon steels, low alloy steels, alloy steels, tool steels. Sulfide stress cracking is a function of hydrogen sulfide concentration as low as ppm, hydrogen sulfide partial pressure, stresses, material yield strength, temperature and ph. Sulfide stress cracking mostly occurs in very highly acidic environments. Also in the process of crude oil processing, due to high temperature, high pressure and catalyst, some sulfide starts to break down at 120. It should not be confused with the term stress corrosion cracking which is an anodic cracking mechanism. In the presence of oxygen aerobic, some bacteria may directly oxidize iron to iron oxides and hydroxides, other bacteria oxidize sulfur and produce sulfuric acid causing biogenic sulfide corrosion. Mild steel is a popular structural steel in this industry but is susceptible to surface scale formation and associated corrosive action, the prevention of which requires some. H 2 s becomes severely corrosive in the presence of water. Modeling and experimental insights of sulfide stress cracking. Sulfide stress cracking an overview sciencedirect topics. The conjoint action of a tensile stress and a specific corrodent on a material results in stress corrosion cracking scc if the conditions are sufficiently severe.
Bacteria accumulation can lead to pitting of steel, and the buildup of h2s increases the corrosiveness of the water, thus increasing the possibility of hydrogen blistering or sulfide stress cracking. Hot cracking is a hightemperature cracking mechanism and is mainly a function of how metal alloy systems solidify. Some sulfatereducing bacteria can reduce hydrocarbons such as benzene, toluene, ethylbenzene, and xylene, and have been used to clean up. In other words, it can support a stress of 80,000 psi with an elongation of less than 0. Their geometry is such that if they grow to appropriate lengths they may reach a critical size that results in a transition from the relatively slow crack growth rates associated with stress corrosion to. Microbial corrosion wikimili, the free encyclopedia. A corrosive medium especially chloridebearing or hydrogensulphide h 2 s media. Sulfatereducing bacteria are active in the absence of oxygen anaerobic.
Sulfide stress cracking is the worst type of corrosion in the presence of hydrogen sulfide. It results in the brittle failure of otherwise ductile materials when exposed to an environment where hydrogen can enter the metal. Stress corrosion cracking scc results from the combined action of three factors. Basically, the failure mechanism of ssc includes an initiation step followed by a propagation step of a crack. Stresscorrosion crackinga cracking process requiring the simultaneous action of a corrodent and sustained tensile stress.
There are maximum acceptable h 2 s concentration limits in sale quality oil and gas, which require. Ssc is a form of spontaneous brittle breakdown in occurring in highstrength. Pdf sulfide stress corrosion cracking and hydrogen. Hydrogen sulfide h 2 s is a colorless, flammable, and extremely hazardous gas with a strong rotten egg odor. Thorough understanding of scc mechanisms of dss in chloride and hydrogen sulfidecontaining solutions has been useful for material selection in many. H 2 s damage can lead to rapid and extensive damage to metals, including uniform corrosion, pitting, and stepwise cracking. The failure characteristics in ssc are most consistent with a hydrogen embrittlement mechanism where the fracture modes are mostly.
The experimental results show that the combined action. Jul 25, 2017 sulfide stress cracking ssc is a form of hydrogen embrittlement which is a cathodic cracking mechanism. The scc of materials in acidic solutions containing dissolved hydrogen sulfide h 2s has been termed as sulfide stress cracking ssc. Hydrogeninduced cracking hic and sulfide stress cracking ssc hydrogeninduced cracking results from the combined action of a tensile stress and hydrogen in the metal. This broad term reflects the role of environment plays in the cracking process and the terms now covers all the following. Stress corrosion cracks propagate over a range of velocities from about 103 to 10 mmh, depending upon the combination of alloy and environment involved. Generally, when designing against stress corrosion cracking, e. Environmental cracking results from the conjoint action of three components.
Cracking mechanism an overview sciencedirect topics. The main observed corrosion products were iron sulfides and the typical damage associated with hydrogen sulfide presence was sulfide stress cracking ssc. Hydrogen sulfide corrosion and its prevention is an important topic in a range of industrial processes and environments including oil and gas and its related activities. Abstract quenched and tempered martensitic steels for oil country tubular goods can be subject to sulfide stress cracking ssc when exposed to a sour environment.
The blistering damage tends to form parallel to the surface and to the direction of hoop stress. Corrosion is a natural process that converts a refined metal into a more chemicallystable form such as oxide, hydroxide, or sulfide. Types of corrosion materials selection guide swagelok. Sewer network structures are prone to biodeterioration of materials due to the action of some microorganisms associated to the sulfur cycle. Review on stress corrosion and corrosion fatigue failure of. Sulphide stress cracking is prevented by minimising the hardness and strength of. The fes generated in the high temperature environment are exposed to moist air when the equipment is turned on, and the sulfuric acid is formed to cause the sulfide stress corrosion cracking sscc. The use of dss has been restricted in some cases because of stress corrosion cracking scc, which can initiate and grow in either the ferrite or austenite phase depending on the environment. In a previous post, we discussed the broad differences between anodic and cathodic forms of environmentally assisted cracking eac. Sulfide stress cracking ssc is a form of hydrogen embrittlement which is a cathodic cracking mechanism. The corrosion type, corrosion mechanism and anticorrosion. Hydrogen sulfide is a colorless, very poisonous, flammable gas with the characteristic foul odor of rotten eggs. Processes or conditions involving wet hydrogen sulfide, i. For this reason, it is crucial to understand eac mechanisms and kinetics and to quantify.
Hydrogen stress cracking hsc, defined as the cracking of a metal under the combined action of tensile stress and corrosion in the presence of water and nascent h, is exacerbated by applied cathodic potentials, figure 1 right. A study on the mechanism of stress corrosion cracking of. The authors conducted extensive analyses to explore the effects of metallurgical factors on the resistance of line pipe steels to hydrogen induced cracking hic and sulfide stress cracking ssc. Element performs sulfide stress cracking ssc testing of metals subject to cracking under the combined action of tensile stress and corrosion in the presence of water and h2s, in compliance with nace tm0177 iso 15156 standards. Sulfide stress cracking is a form of hydrogen embrittlement that occurs in highstrength steels and in localized hard zones in weldment of susceptible materials when the environment contains wet h 2 s. As a form of hydrogen stress cracking, ssc is a cracking mechanism in pipelines, facilities piping and any equipment that comes in contact with sour wet h2s service conditions. As a form of hydrogen stress cracking, ssc is a cracking mechanism in pipelines, facilities piping and any equipment. Hic usually occurs due to the effects of aqueous hydrogen charging of steel in wet h2s refinery process environments.