Hydrogen sulfide stress cracking

Sulfide stress cracking of nickelcontaining lowalloy. 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. 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. Sulfide stress cracking is a form of hydrogen embrittlement that occurs in highstrength steels and in localized hard zones in weldment of susceptible materials. More extensive use of the wet fluorescent magnetic particle technique in recent years as a refinery equipment inspection tool has highlighted the extent and magnitude of the. Effect of coldwork on sulphide stress cracking resistance. However, under certain stress and material conditions, the cracks can be arranged in a ladderlike array known as stress orientated hydrogen induced cracking sohic. In that article, we concluded that while localized corrosion appears to be a prerequisite for anodic eac modes such as stress corrosion cracking scc, hydrogen assisted eac mechanisms like hydrogen stress cracking hsc are exacerbated at cathodic potentials. Feb 04, 2010 hydrogen sulfide principles safety sample. Sulfide stress cracking is the worst type of corrosion in the presence of hydrogen sulfide. Sulfide stress cracking ssc vs hydrogen induced cracking. This condition can lead to embrittlement of the material, resulting in cracking under the combined action of tensile stress and corrosion.

Pdf sulfide stress corrosion cracking and hydrogen induced. It involves atomic hydrogen, which is the smallest atom, that diffuses into a metallic structure. Metal fatigue, including hydrogen embrittlement, or sulfide stress cracking, can result in equipment failure, which can release h 2 s gas, and lead to h 2 s exposure and injury. Sulfide stress cracking ssc vs hydrogen induced cracking hlc posted in refining, hydrocarbons, oil, and gas. The role of hydrogen in sulfide stress cracking in low alloy steels. It is generally recognised that the risk of sulphide stress corrosion cracking in ferritic steels increases with hardness, and maximum hardness limits are the basis of guidelines for. There is a general agreement that plastic strain affects the resistance to sulphide stress cracking, even possibly for low amounts of strain and without significant changes in hardness. Sulfide stress cracking is also called hydrogen sulfide cracking, sulfide cracking, sulfide corrosion cracking and sulfide stress corrosion cracking. In a previous post, we discussed the broad differences between anodic and cathodic forms of environmentally assisted cracking eac. 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. Hydrogen sulfide h2s training training objectives describe. Hydrogeninduced craking hic, also referred to as hydrogen stress cracking or static fatigue, is a typical form of hydrogen embrittlement. Ssc is a form of hydrogen stress cracking resulting from absorption of atomic hydrogen that is produced by the sulfide corrosion reaction on the metal surface. Sulfides can be generated from soluble iron sulfide minerals or from sulfatereducing bacteria.

While these metals may normally be ductile in nature, the presence of hydrogen in a corroded environment can cause it to crack. The role of hydrogen in sulfide stress cracking of low. One of the more common problems is ssc, sulfide stress cracking. Sulfide stress cracking is also called hydrogen sulfide cracking, sulfide cracking, sulfide corrosion cracking and sulfide stresscorrosion cracking. Hydrogen sulfide stress corrosion cracking in materials. There are maximum acceptable h 2 s concentration limits in sale quality oil and gas, which require. 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. The effect of low h2s concentrations on welded steels march. Sulfide stress cracking an overview sciencedirect topics. Jun 03, 2018 hydrogeninduced cracking hic refers to the internal cracks brought about by material trapped in budding hydrogen atoms.

Tcr engineering mumbai corrosion testing, nace, astm. Hydrogen induced cracks either follow a linear or stepwise path within the material, hence the term stepwise cracking. Sulphide stress cracking is prevented by minimising the hardness and strength of the alloys used for wet h2s systems. 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 crackingnace mr01752002, mr0175iso 15156 652 te c h n i c a l so slow that the critical concentration is never reached. Sulfide stress cracking effects high strength effects high strength carbon steels above rockwell hardness 22 especially in petroleum production and petroleum refining. When operating in a zone with h 2 s present, you must use equipment that is constructed of materials with metallurgical properties that resist or prevent sulfide stress cracking also known as hydrogen embrittlement, stress corrosion cracking, or h 2 s embrittlement, chloride stress cracking, hydrogen induced cracking, and other failure modes. Hydrogen sulphide gas is a poisonous gas and cannot be emitted into the environment without treatment, thus hydrogen sulphide cracking process has. 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.

Jul 25, 2017 sulfide stress cracking has special importance in the gas and oil industry, as the materials being processed there natural gas and crude oil often contain considerable amounts of hydrogen sulfide. These valve bodies have been operating satisfactorily for 3 years in wet h2s environment before some pits and cracks were detected in all of them during the. Sulfide stress corrosion cracking sscc sulfide stress cracking effects high strength effects high strength carbon steels above rockwell hardness 22 especially in petroleum production and petroleum refining. Environmental cracking is a broad term that includes corrosion fatigue, hightemperature hydrogen attack, hydrogen blistering, hydrogen embrittlement, liquid metal embrittlement, season cracking, caustic embrittlement, stress corrosion cracking, stepwise cracking, sulfide corrosion cracking and sulfide stress cracking.

In 2003, an uncontrolled release form a natural gas well in chongqing, china, led to the deaths of 240 people. The term active sulfide is used to denote compounds that revert to h 2 s gas when acidified with 2molar citric acid solution, as. The h2s causes the hydrogen to enter the metal structure rather than bubble off from the surface. Factors affecting the sulfide stress cracking performance. Initial theories that ssc was a form of stress corrosion cracking eventually gave way to the current understanding that the phenomenon is caused by hydrogen. Sulfide stress cracking nace mr01752002, mr0175iso 15156 652 te c h n i c a l so slow that the critical concentration is never reached. Some researchers consider sulfidestress cracking a type of stresscorrosion cracking, while others consider. The influence of chemical composition and microstructure of api linepipe steels on hydrogen induced cracking and sulfide stress corrosion cracking. This is a type of deterioration which can be linked to corrosion and corrosioncontrol processes.

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. This nace standard establishes material requirements for resistance to sulfide stress cracking ssc in sour refinery process environments, i. May 07, 2019 sulfide stress corrosion cracking occurs in presence of hydrogen sulfide. It is characterized by the brittle fracture of a normally ductile alloy under sustained load in the presence of hydrogen.

Sulfide, s2, and bisulfide, hs, are the corresponding ionic forms. 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. 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. In this chapter the terms eac and scc are generally interchangeable. This penetration can lead to the brittle fracture of materials that are normally ductile when hydrogen happens to be present in their environment. It is a complex process that is not completely understood because of the variety and complexity of mechanisms that can lead to embrittlement. However, the evidence heretofore has been mostly circumstantial. Effect of coldwork on sulphide stress cracking resistance twi. It should not be confused with the term stress corrosion cracking which is an anodic cracking mechanism. Sscc is a specialized case of hydrogen cracking as it may be possible that sulfide stress corrosion cracking and hydrogen cracking. This term should not be confused with stress corrosion cracking scs, since this is anodic in nature. Highstrength steels with improved sulfide stress cracking resistance. Oil and gas well drilling and servicing etool general.

This standard is applicable to the materials andor equipment specified by the materials standards institutions listed in. It is generally recognised that the risk of sulphide stress corrosion cracking in ferritic steels increases with hardness, and maximum hardness limits are the basis of guidelines for avoidance of cracking in many standards. Hydrogen stress cracking occurs when hydrogen penetrates highstrength or hardened metal in a state of tensile stress. Paper 143, corrosion 2000, nace international, orlando, florida, usa, 2631 march 2000. Sulfide stress cracking ssc is a type of hydrogen cracking which presents a cathodic embrittlement mechanism. Sulfide stress corrosion cracking ssc is a form of hydrogen embrittlement cracking which occurs when a susceptible material is exposed to a corrosive environment containing water and h2s at a critical level of applied or residual tensile stress. Is sulfide stress cracking an anodic or a cathodic process. Dec 19, 2019 sulfide stress cracking ssc is a type of hydrogen cracking which presents a cathodic embrittlement mechanism. Some researchers consider sulfide stress cracking a type of stress corrosion cracking, while others consider. However, available data remains scarce, in particular, few studies if any have published sufficient details for a full examination of the mechanisms at work. Sulfide stress cracning ssc is a form of hydrogen embrittlement which is. The role of hydrogen in sulfide stress cracking of low alloy.

As we know that both form of cracking are due to the absorption of atomic hydrogen that is produced by. Sulfide stress corrosion cracking of steels corrosion. The effect of low h2s concentrations on welded steels. The pipeline steels operating in sour environments with presence in many cases of water and other corrosive agents, are subject to three specific corrosion mechanisms typically caused by wet hydrogen sulfide. Brown, a round robin laboratory assessment of hydrogen induced cracking and sulfide stress corrosion cracking of line pipe steelsresults variation and proposals for a. Standard material requirements materials resistant to. Ansinaceiso mr0103hd2010, materials resistant to sulfide. However, at these low strengths, tubing collapse was encount ered and limited the strength of the joints. Pdf sulfide stress corrosion cracking and hydrogen. The effects of sulfide stress cracking on the mechanical properties.

Sulfide stress cracking has special importance in the gas and oil industry, as the materials being processed there natural gas and crude oil often contain considerable amounts of. When operating in a zone with h 2 s present, you must use equipment that is constructed of materials with metallurgical properties that resist or prevent sulfide stress cracking also known as hydrogen embrittlement, stress corrosion cracking, or h 2 s embrittlement, chloridestress cracking, hydrogeninduced cracking, and other failure modes. 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. Environmental cracking is a broad term that includes corrosion fatigue, hightemperature hydrogen attack, hydrogen blistering, hydrogen embrittlement, liquid metal embrittlement, season cracking, caustic embrittlement, stresscorrosion cracking, stepwise cracking, sulfide. Sulfide stress cracking ssc occurs at locations where atomic hydrogen is able to diffuse at sites of high internal stress, such as grain boundaries, inclusions and regions of triaxial stress at notches. Sulfide stress cracking ssc is a form of hydrogen embrittlement which is a cathodic cracking mechanism. Sulfide stress cracking ssc occurs at locations where atomic hydrogen is able to diffuse at sites of high internal stress, such as grain boundaries, inclusions and. 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. 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. Hydrogen induced craking hic, also referred to as hydrogen stress cracking or static fatigue, is a typical form of hydrogen embrittlement. Susceptible alloys, especially steels, react with hydrogen sulfide, forming metal sulfides and atomic hydrogen as corrosion byproducts.

Sulfide stress cracking is a form of hydrogen embrittlement that occurs in high strength steels and in localized hard zones in weldment of susceptible materials. Ssc is one of the many environmental cracking mechanisms resulting in pipeline steels exposed to aqueous sour service environments. The variation of the name is due to the lack of agreement in the mechanism of failure. This standard presents metallic material requirements for resistance to sulfide stress cracking ssc for petroleum production, drilling, gathering and flowline equipment, and field processing facilities to be used in hydrogen sulfide h2sbearing hydrocarbon service. 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. Sulfide stress cracking oil and gas pipelines wiley. Sulfide stress cracking ssc testing southwest research. It is intended to be used by refineries, equipment manufacturers, engineering contractors, and construction contractors. Wet hydrogen sulfide cracking is a term used for a variety of stress corrosion cracking scc failure modes of carbon steel exposed to aqueous sour refinery environments. 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.

Sulfide stress corrosion cracking occurs in presence of hydrogen sulfide. Most deaths occurred in the area 200 to 500 meters 16th to rd of. In this environment, not only is hydrogen sulfide stress cracking a concern, but the presence of brine or salt water introduces the additional. Hydrogeninduced cracking hic refers to the internal cracks brought about by material trapped in budding hydrogen atoms. Select materials in h 2 s service in accordance with nace specifications.

The possibility that cold work affects the resistance to sulphide stress cracking is not unrecognised. 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. It is intended to be used by refineries, equipment manufacturers, engineering contractors, and. Sulfide stress cracking ssc is just one of several forms of hydrogen. Hydrogen sulfide is a colorless, very poisonous, flammable gas with the characteristic foul odor of rotten eggs. Corrosionpedia what is sulfide stress cracking ssc. Hydrogen sulfide stress corrosion cracking in materials for. Sulfide stress cracking nace mr01752002, mr0175iso 15156. Corrosionpedia what is hydrogeninduced cracking hic. Sscc is a specialized case of hydrogen cracking as it may be possible that sulfide stress corrosion cracking and hydrogen cracking proceed simultaneously. Sulfide stress cracking is a form of hydrogen embrittlement that occurs in highstrength steels and in localized hard zones in weldment of susceptible. It is generally accepted that sulfide stress cracking ssc failures are the result of hydrogen embrittlement.

Critical nominal stress and critical stress intensity factors for sulfide stress corrosion cracking of various steels were determined using fatigueprecracked, laboratory, cantilever beam specimens and short lengths of oil field casing and tubing pressured to failure. Gas phase water needs to be there as well even in a trace amount. The purpose of this paper is to provide the experimental evidence which establishes the causality of hydrogen and the contributory roles of h 2 s and. Sulfide stress corrosion cracking, also known as sulfide stress cracking ssc, is a stress corrosion cracking phenomena that occurs in the presence of hydrogen. Above 120f 49c, the diffusion rate is so fast that the hydrogen. When placed in proximity to tensile stresses, embrittlement and the beginnings of brittle fracture may occur. There is a wide range of damage mechanisms that can occur due to the effect of hydrogen charging in wet h2s environments. Sulfide stress cracking nace mr01752002, mr0175iso. Sulfide stress cracking mostly occurs in very highly acidic environments. Types of corrosion materials selection guide swagelok. H 2 s becomes severely corrosive in the presence of water. In this environment, not only is hydrogen sulfide stress cracking a concern, but the presence of. Hydrogen sulphide stress corrosion cracking in materials for. 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.