Pdf sulfide stress corrosion cracking and hydrogen induced. Corrosionpedia what is sulfide stress cracking ssc. Sulfide stress cracking nace mr01752002, mr0175iso 15156. However, the primary concern with the presence of h 2 s is the risk of causing sulfide stress cracking ssc. Sulfide stress cracking ssc testing southwest research. The hydrogen sulfide concentration of the gas to be transported is 11, 000 parts per million. Hydrogen sulfide gas is a toxic gas found in oil and gas reservoirs. Sulfide stress cracking ssc is a form of hydrogen embrittlement which is a cathodic cracking mechanism. The effects of sulfide stress cracking on the mechanical properties. Hydrogen sulfide gas properties and safety with h2s. The line will be operated at a maximum pressure of 1,358 psig.
Pdf the consequences of cracks formed on the oil and gas. Sulfide stress cracking of a pipeline weld in sour gas. Sulfide stress cracking oil and gas pipelines wiley. Ssc testing, proof ring, stress corrosion cracking. Hydrogen sulfide when dissolved inwater is a weak acid, and therefore, it is a source of hydrogen ions. Sulfide stress cracking ssc is just one of several forms of hydrogen. It should not be confused with the term stress corrosion cracking which is an anodic cracking mechanism. Hydrogen sulfide h 2 s is a naturally occurring gas that can be deadly to humans and corrosive to oil and gas equipment, especially in the presence of water.
Sulfide stress cracking ssc is one of the most dangerous types of pipelines destruction. No matter how well these pipelines are designed, constructed and protected, once in place they are subjected to environmental abuse, external damage, coating disbondments, inherent mill defects, soil movementsinstability and third party damage. But, the presence of h 2 s in well fluids imposes severe restrictions on the use of tubular goods due to sulfide stress cracking phenomenon 2. These cracks are usually formed in the pipe mill for seam welds or during pipeline construction for girth welds. Biaxial stress corrosion cracking frames capable of conducting testing in aggressive environments, such as brines with co 2 and h 2 s. Amine cracking typically occurs on the surface and the cracks are usually. Sulfide stress cracking an overview sciencedirect topics. Nace standard mr0175, standard material requirementsmetals for sulfide stress cracking and stress corrosion cracking resistance in sour oilfield environments for sulfide stress cracking resistant metallic material for oilfield equipment, sec. Pdf the influence of chemical composition and microstructure of. To apply these pipes in onshore pipeline construction, in addition to the challenge of producing.
Api linepipe steels on hydrogen induced cracking and sulfide stress corrosion. Sulfide stress cracking was first identified as a serious problem in the oil industry in the late international journal of engineering trends and technology ijett volume 54 number 4 december. Corrosion is related to the susceptibility of the material to the environment, while. Hydrogen sulfides corrosiveness can result in sulfide stress corrosion cracking in the welded material. Proceedings of the asme 2016 pressure vessels and piping conference. Environmentally assisted cracking eac is a general term that includes processes such as stress corrosion cracking scc, hydrogen embrittlement he, sulfide stress cracking ssc, liquid metal embrittlement lme, and corrosion fatigue cf. Cold cracking in weld metal requires the presences of hydrogen, a susceptible weld metal microstructure and stress, so cracks typically form in the longitudinal direction. On pipeline exteriors, welds are exposed to lower hydrogen concentrations than those in contact with the sour environment found on surfaces inside the pipeline. This paper describes the investigation of this unusual failure, indicates probable causes, and outlines potential changes in repair. Hydrogen induced cracking hic is a form of tiny blistering damage caused by a high concentration of hydrogen in steel. 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.
Materials that carry sour oil or gas need to have special properties to increase their resistance to hydrogen sulfide stress cracking. Review and critical assessment of hardness criterion to avoid sulfide stress cracking in pipeline welds. Amine cracking is often intertwined with wet hydrogen sulfide h 2 s and carbonate cracking, as amines, carbonates and wet sulfides often exist together in amine treating systems. In that time other improvement in pipeline industry procedures, as testing all new pipeline construction by a hydrostatic pressure field test. Summary sulfide stress cracking ssc is just one of several forms of hydrogen.
Sulfide stress cracking ssc was first identified and the mechanism outlined in the 1940s after several failures of oil and gas systems in texas and canada. Following aqueous corrosion reactions in the presence of h2s on the pipe internal surface, atomic hydrogen is produced and absorbed in the pipe steel. Sulfide stress cracking of pipelinecase history onepetro. In this environment, not only is hydrogen sulfide stress cracking a concern, but the presence of brine or salt water introduces the additional. However, even if the effect of strain hardening has been taken into account, and the weldment hardness after pipe laying does not therefore exceed the allowable. Ssc is one of the many environmental cracking mechanisms resulting in pipeline steels exposed to aqueous sour service environments. Ssc sulfide stress cracking st seat std standard stl steel stm steam svc service. Stress corrosion cracking of carbon steel in carbonate. It can lead to unexpected sudden failure of normally ductile metal alloys subjected to a tensile stress, especially at elevated temperature. Houston highquality, defectfree welds can be deposited in api grade 5l x80 line pipe with pulsed gas. Sulfide stress cracking oil and gas pipelines wiley online library. Zou, characterization of the effect of hydrogen sulfide on the corrosion of x80 pipeline steel in saline solution. H2sbearing fluids, must be constructed of h2s corrosionresistant materials or.
H2s can cause sulfide stress cracking of stainless steels. Proof rings and associated accessories are manufactured to meet requirements of nace tm0177 and material standard. It is a progressive type of failure that produces cracking at stress levels that are well below the materials tensile strength. Sulfide stress cracking ssc of high strength, low alloy steel is a phenomenon of particular concern to the oil and gas industry 3. For a typical pipe steel with chemical analysis in the range of api x60. Wet hydrogen sulfide h2s cracking inspectioneering. Strain and sulfide stress cracking in pipeline girth welds. Hic and ssc behavior of highstrength pipeline steels. It is often referred to as sour gas in the oil and gas industry. These include determining the effects of h2s, co2, oxygen, and microbiological organisms on corrosioncracking of pipeline materials. The blistering damage tends to form parallel to the. Construction industry institute, the university of texas at austin, 3925west braker lane r4500, austin, texas 78759. Amine cracking is a form of stress corrosion cracking, which is related to alkaline and carbonate stress corrosion cracking. Abstract a replacement girth weld in a wet, sour gas gathering pipeline fuelled within 72 hours of start of operation.
Micro alloyed pipeline steels are commonly used in the petroleum industry for transport applications 1. However, the production of x70 and x80 for sour service application is a big challenge that requires a more complex production route to ensure resistance against sulfide stress cracking refs. A discontinuity, such as a crack, gouge, notch, or geometry change that causes an intensification of the local stress. Strain and sulfide stress cracking in pipeline girth welds twi. Thermal impact of the welding process drives to heterogeneity of the microstructure and properties of the. Be observant for signs of pipeline damage, leakage, or security concerns. Scc is highly chemically specific in that certain alloys are likely to undergo scc only when exposed to a small number of chemical environments.
In this chapter the terms eac and scc are generally interchangeable. This paper describes work performed under a short study programme into the sulfide stress corrosion cracking behaviour of samples taken from a pipe girth weld that were strained to conditions that simulated those of a typical pipe reeling and laying operation. Sulfide stress cracking is prevented by minimizing the hardness and strength of the. Pipeline materials and construction will meet the nace standards as required by statewide rule 36 for hydrogen sulfide service. Sulfide stress cracking mostly occurs in very highly acidic environments. Corrosion control in oil and gas pipelines pipeline. Effect of temperature on the corrosion behavior of api. From observations of the characteristics of nitrate and hydroxide solutions, known to promote stress corrosion cracking scc in carbon steels, and from the form of potentiodynamic polarization curves and the structural dependence of the corrosive attack, it was predicted that carbonate solutions would also produce intergranular stress corrosion in. Webcorr provides corrosion consultancy services, corrosion expert witness and corrosion short courses for inhouse training, online and distance learning. Sulfide stress cracking is the worst type of corrosion in the presence of hydrogen sulfide.
By now about 60% of large diameter gas pipelines in russia are subject to undercoating corrosion processes, the most hazardous of which is stress corrosion cracking scc. Welding needs specified for x80 offshore line pipe oil. Effect of temperature on the corrosion behavior of api x120 pipeline steel in h 2. Explains why pipeline stress corrosion cracking happens and how it can be prevented. Although h2s is not corrosive by itself, it becomes a severely corrosive agent in the presence of water,leading to pipeline embrittlement. Sour cracking hic, sulfide stress corrosion cracking sscc environmentally assisted cracking can also occur internally in pipelines. Sulfide stress cracking ssc of high strength, low alloy steel is a phenomenon of particular. Sulfide stress cracking can be induced in susceptible materials by the simultaneous presence of tensile stresses and a corrosive environment containing a. Yang, role of microstructure on sulfide stress cracking of oil and gas pipeline steels. What causes stress corrosion cracking in pipelines. Sulfide stress cracking ssc is a type of hydrogen cracking which presents a cathodic embrittlement mechanism. Stress corrosion cracking scc is a type of environmentallyassisted cracking eac, or the formation of cracks caused by various factors combined with the environment surrounding the pipeline. Stress corrosion cracking scc is the growth of crack formation in a corrosive environment.
The national association of corrosion engineers nace test method tm0177 is widely used to qualify metals for resistance to sulfide stress cracking and stress corrosion cracking in h 2 s environments. 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. The original 1997 cepa stress corrosion cracking recommended practices hereafter referred to as the practices were prepared and made. Providing resistance to sulfide stress corrosion cracking.
Susceptible alloys, especially steels, react with hydrogen sulfide, forming metal sulfides and atomic hydrogen as corrosion byproducts. Review and critical assessment of hardness criterion to. Specialized stress corrosion cracking testing capabilities. Roles of hzs in the behavior of engineering alloys. This term should not be confused with stress corrosion cracking scs, since this is anodic in nature. By implementing the requirements of the regulation and through responsible maintenance programs, pipeline operators continuously inspect their pipelines for indications of scc. Mechanism of sulfide corrosion hydrogen sulfide corrosion can occur by two mechanisms. This has long been recognized and prompted the development of the nace standard mr0175 sulfide stress cracking resistant metallic materials for oilfield equipment. 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. Scc occurs as a result of a combination between corrosion and tensile stress. Caltech engineering services india manufacture and supply proof ring to test and accurately determine the resistance to sulfide stress corrosion cracking ssc and stress corrosion cracking of metals in h2s environment or service. The most common conditions for these are sour environments.
Regularities of pipelines stress corrosion cracking 15th. Recicly mechanical properties structure and synthesis of polymer. Producing wet sour gas presents some of the toughest technical challenges in the oil and gas business. The obtained results indicate that the hydrogen sulfide is the most active gas in the corrosion processes that took place, quite above carbon dioxide. Two selected pipes, both longitudinal and transverse specimens for pipe. The main observed corrosion products were iron sulfides and the typical damage associated with hydrogen sulfide presence was sulfide stress cracking ssc.
The report considers sccspecific prediction models for pipes steels describing main stages of the process, rate and implementation conditions. Girth welding of api 5l x70 and x80 sour service pipes. In this study, hydrogeninduced cracking hic and sulfide stress corrosion cracking ssc behaviors of highstrength pipeline steels in four different strength grades x70, x80, x90 and x100 with the microstructure of acicular ferrite were estimated. Pipeline design consideration and standards petrowiki. Test frames for applying cyclic loads with the measurement of crack propagation rates. Environmental cracking in line pipe carrying sour product. Rosen 15 types of pipeline cracks inspection solutions. Testing conforms to nace, astm, api, or iso standards and test materials are analyzed for mass loss, localized corrosion or stress corrosion cracking sscsulfide stress cracking ssc. When they are in good working order, they deliver fuel to meet the evergrowing demand for energy around the world. The canadian energy pipeline association cepa is a voluntary, nonprofit industry association representing major canadian transmission pipeline companies. Welding equipment and consumables for the pipeline industries.