The rapid cooling can be compensated by increasing heat input, but the increased heat input can promote weld penetration and the possibility of meltthrough. Sulfide stress cracking of a pipeline weld in sour gas. Then the defected spool pipe was replaced by a 4m new spool pipe and the pipeline was back to. Therefore, it is a source of hydrogen ions and is corrosive. It should not be confused with the term stress corrosion cracking which is an anodic cracking mechanism.
May 29, 2018 the sulfide stress cracking ssc resistance of api x65 grade steel weldment has been studied using ssc test in nace tm0177 method a and the applied load was 72108 % of yield strength. Ssc proof rings 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. Environmentallyassisted cracking scc, corrosion fatigue, hydrogen induced, sulfide stress cracking, selective seam corrosion manufacturingrelated anomalies lack of fusion, cold welds, stitching, and hook cracklike features a description of factors that drive their stable growth leading to failures. The sulfide stress cracking ssc resistance of api x65 grade steel weldment has been studied using ssc test in nace tm0177 method a and the applied load was 72108 % of yield strength. Guidelines for developing a procedure for the weld repair. The critical stress sc values of these three microstructures were determined experimentally to be 1008, 1190, 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. Scc occurs as a result of a combination between corrosion and tensile stress. When the pipelines are exposed for many years to wet h2s environments, they can fail due to hydrogen embrittlement. Manufacturing related anomalies lack of fusion, cold welds, stitching, and hook cracklike features operational driven fatigue cracks in the body of the pipe and weld toe. Mar 16, 2020 excellent hydrogeninduced cracking hic and sulfide stress corrosion cracking sscc resistance. The effect of peak weld hardness was examined by using three welding conditions. Hydrogen embrittlement can occur during various manufacturing operations or operational use anywhere that the metal comes into contact with atomic or molecular hydrogen. The most common conditions for these are sour environments. A sour service pipeline environment is defined by nace international specification mr017 as fluids containing water and hydrogen sulfide h2s that is a total pressure of 0. Performance of welded highstrength lowalloy steels in sour. This paper reports the sulfide stress corrosion cracking ssc behavior of line pipe steel investigated using the ssc test method in nace standard tmo17777, testing of. Minimizing hydrogen cracking critical for cr pipeline.
Excellent hydrogeninduced cracking hic and sulfide stress corrosion cracking sscc resistance. In this work, the hydrogen sulfide stresscorrosion cracking ssc susceptibility of a welded api x80 pipeline was investigated. There are many types of cracks, including stress corrosion cracking scc, fatigue cracking, hydrogeninduced cracking hic and sulfide stress cracking ssc. Sulfide stress cracking an overview sciencedirect topics. Sulfide stress cracking ssc behavior of three microstructures, i. Therefore, for verification that x80 material has acceptable resistance to either hic, sulfide stress corrosion cracking, or stress oriented hic in sour service, fullscale tests must be carried out. Strain and sulfide stress cracking in pipeline girth welds. Abstract for sour service conditions there are stringent weldment hardness requirements that must be satisfied in order to minimise the risk of sulfide stress corrosion cracking ssc in service. The susceptibility to hydrogen embrittlement of the welds could be reduced significantly by subjecting the welds to 600c2 h tempering. In carbon steel line pipe material, microalloy additions make welds resistant to. The critical stress sc values of these three microstructures were determined. Review and critical assessment of hardness criterion to avoid.
Environmentally assisted cracking scc, corrosion fatigue, hydrogen induced, sulfide stress cracking, selective seam corrosion and. Kermani m b, harrop d, truchon m l r and crolet j l. Sulphide stress corrosion cracking is a major problem to be analysed during pipeline girth welds. Thus, suitable welding procedures must ensure optimal haz hardness, no meltthrough, and proper heat input. Corrosionpedia what is sulfide stress cracking ssc. Sulfide stress cracking is the worst type of corrosion in the presence of hydrogen sulfide. The effect of strain on the suspectability of pipeline. Review and critical assessment of hardness criterion to. Sulfide stress cracking is prevented by minimizing the hardness and strength of. Weld metal corrosion is normally attributed to the differences in composition and to differences in electrochemical potentials between the parent metal, heataffected zone haz, and weld metal. Sulfide stress cracking ssc is the failure of steel caused by the simultaneous action of stress and hydrogen absorbed from corrosion. Ssc testing, proof ring, stress corrosion cracking. For gas pipelines, where the water will be condensed water, it is reasonable to calculate the ph based on the operating temperature and pressure and the concentration of carbon dioxide.
This type of cracking is also known as underbead cracking, toe cracking, or delayed crack. Sulfide stress cracking of nickelcontaining lowalloy steels. Corrosion is related to the susceptibility of the material to the environment, while stresses may be. The x65 grade pipe steel consisted of finegrained ferrite and a small volume fraction of pearlite. Sour cracking hic, sulfide stress corrosion cracking sscc environmentally assisted cracking can also occur internally in pipelines. The consequences of cracks formed on the oil and gas pipelines weld joints.
Most buried pipelines that have been in service for five or more years experience numerous. Sulfide stress cracking susceptibility of welded x60 and. Sulfide stress cracking susceptibility of welded x60 and x. Highstrength steels with improved sulfide stress cracking resistance. They occur in the base material of the pipe, in welds and in heataffected. Susceptibility of pipeline girth welds to hydrogen embrittlement and. Water with hydrogen sulfide alone does not cause disease. 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.
Welding research effect of welding parameters and h2s. Providing resistance to sulfide stress corrosion cracking of pipelines. Analysis of stress corrosion cracking of x65 oil pipeline stress. Ssc testing, proof ring, stress corrosion cracking, sulfide. For oil field equipment, the nace mr0175 standard recommends a maximum hardness of 22hrc approximately 248 hv in carbon and low alloy steels to avoid sulphide stress corrosion cracking sscc. Welding research numerical simulation of sleeve repair. After welding, compact modifiedwedge opening loading mwol fracture mechanics specimens were machined and loaded to. Sulfide stress cracking of nickelcontaining lowalloy. The most typical forms for cracking are environmentally assisted, manufacturing related, and operational driven. Webcorr provides corrosion consultancy services, corrosion expert witness and corrosion short courses for inhouse training, online and distance learning. Explains why pipeline stress corrosion cracking happens and how it can be prevented pipelines sit at the heart of the global economy.
Heat affected zone haz cracking figure 5 is characterized by separation that occurs immediately adjacent to the weld bead. Hydrogen sulfide is particularly dangerous to equipment when moisture is present. Safe weld hardness levels to insure long service life in offshore pipelines, offshore technology conference, may, 1972, houston texas, paper otc 1571. Role of microstructure on sulfide stress cracking of oil and. What causes stress corrosion cracking in pipelines. Welding processes are utilized to produce pipeline segments seam and spiral welds and join pipeline segments girth welds in the field. The effect of cold work and strain ageing on the sulfide stress cracking resistance and mechanical properties of expanded tubular steels a laboratory study. Susceptible alloys, especially steels, react with hydrogen sulfide, forming metal sulfides and atomic hydrogen as corrosion byproducts. Following aqueous corrosion reactions in the presence of h2s on the pipe internal surface, atomic hydrogen is produced and absorbed in the pipe steel. Hydrogen sulfides corrosiveness can result in sulfide stress corrosion cracking in the welded material. Wet h 2 s corrosion can be a particularly dangerous form of corrosion because damage. Sulfide stress corrosion cracking and fatigue crack growth of welded tmcp api 5l x65 pipeline steel. In designing pipeline and process equipment for handling sour containing h 2 s products, limitations are frequently imposed on material hardness. Currently, the main technical standards for oil and gas conveying steel linepipes are api spec 5l, dnvosf101, iso 3183 and gbt 9711, etc.
For this purpose, steel welding was carried out normal to the rolling direction using a 60 single vjoint design. Processes that can lead to this include cathodic protection, phosphating, pickling, and electroplating. Weld hardness was characterized with rockwell c and vick. Therefore, for verification that x80 material has acceptable resistance to either hic, sulfidestress corrosion cracking, or stressoriented hic in sour service, fullscale tests must be. There are no major differences in welding x70 material compared to lowergrade steel, such as x65. Welding and qualification of microalloyed hsla steel weldments, chairman malcolm gray, 1990, pg 327. Sulfide stress corrosion cracking and fatigue crack growth of welded. The iso methodology requires an estimate of the ph of the water that will be present. This prompted for a failure investigation to be carried out. Pipelines for oil and gas, manufactured in highstrength lowalloy steels hsla, such api pipes, promote high levels of strength and fracture toughness. Ppim 2019 managing cracks and seam weld anomalies on pipelines. Susceptibility study to hydrogen embrittlement of welded. Pdf the consequences of cracks formed on the oil and gas.
Stress corrosion cracking of pipelines electrochemistry. As a form of hydrogen stress cracking, ssc is a cracking mechanism in pipelines, facilities piping and any equipment. H 2 s damage can lead to rapid and extensive damage to metals, including uniform corrosion, pitting, and stepwise cracking. Sulfide stress cracking ssc is a type of hydrogen cracking which presents a cathodic embrittlement mechanism. Welding equipment and consumables for pipeline industries from lincoln electric.
Strain and sulfide stress cracking in pipeline girth welds twi. 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 corrosion cracking of line pipe for sour gas service, nace, corrosion 37 1, january 1981. Therefore, it is important to ensure this high level of toughness in the welded joint. Sulfide stress cracking ssc is a form of hydrogen embrittlement which is a cathodic cracking mechanism. When they fail due to stress corrosion cracking, they can wreak environmental havoc. Managing cracking and seam weld anomalies in pipelines clarion. The susceptibility of api x60 and x65 longitudinal weld beads to sulfide stress cracking ssc has been evaluated using slow strain rate tests ssrt in the nace solution saturated with hydrogen sulfide h 2 s.
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. Hydrogen sulfide h 2 s is a colorless, flammable, and extremely hazardous gas with a strong rotten egg odor. Guidelines for developing a procedure for the weld repair of process pipelines in oil refineries. Performance of welded highstrength lowalloy steels in. Dec 19, 2019 sulfide stress cracking ssc is a type of hydrogen cracking which presents a cathodic embrittlement mechanism. Sulfide stress cracking is a form of hydrogen embrittlement that occurs in highstrength steels and in localized hard zones in weldment of susceptible. Proceedings of the asme 2016 pressure vessels and piping conference. But, higher weld metal hardness and a martensitic weld microstructure mean that even lower hydrogen levels are necessary to prevent hydrogeninduced cracking. The tests were supplemented by potentiodynamic polarization curves and hydrogen permeation measurements. V arious forms of cracks, cracklike indications and seam weld anomalies are known to be present on pipelines, which could become a safety concern to their safe operation. Review and critical assessment of hardness criterion to avoid sulfide stress cracking in pipeline welds. However, hydrogen sulfide forms a weak acid when dissolved in water.
Onwards frequent failures began to occur in identical fashion at different locations. Consumables for sour service typically, highstrength carbon steel, grade x70, is used for such subsea jobs. Our pre and post weld heat treatment pwht services provides the clients with. The influence of chemical composition and microstructure of api linepipe steels on hydrogen induced cracking and sulfide stress corrosion cracking. There are instances in which such pipelines gave a long service in sour atmospheres. Rosen 15 types of pipeline cracks inspection solutions. Welding research effect of welding parameters and h2s partial. Material that is hard has an increased risk of failure by sulfide stresscracking. The susceptibility of girth welds to sulphide stress cracking ssc and hydrogen embrittlement he were evaluated for api grade x80 and x56 steels, both for. Sulfide stress cracking susceptibility of local hard areas in carbon. When they are in good working order, they deliver fuel to meet the evergrowing demand for energy around the world. Characteristics of sulfide stress cracking of high strength pipeline steel weld by heat input. After welding, compact modifiedwedge opening loading mwol fracture mechanics specimens were machined and loaded to an applied.
After welding, compact modifiedwedge opening loading mwol fracture mechanics specimens were machined and loaded to an applied stress intensity. Without welding, nothing is possible which relates aircraft to skyrocket, the pipeline to highways, cars to workplace constructions. The consequences of cracks formed on the oil and gas. The susceptibility of welded api 5l x70 and x80 steels to sulfide stress cracking ssc was investigated using two applied stresses and three h 2s concentrations. This book skillfully explains the fundamental science and. This term should not be confused with stress corrosion cracking scs, since this is anodic in nature.
The effect of low h2s concentrations on welded steels. Published on may 23, 2017 may 23, 2017 43 likes 5 comments. A special case is arc welding, in which the hydrogen is released from. 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. Ppim 2019 managing cracks and seam weld anomalies on. Six unstrained, cross weld, four point bend sulfide stress corrosion cracking specimens were machined from the pipe at positions adjacent to the 3 oclock and 9 oclock positions from which the strain specimen blanks had been extracted specimens scc16. Welding needs specified for x80 offshore line pipe oil. Sulfide stress corrosion cracking and fatigue crack growth. Welding onto a gas pipeline in active operation is. It can act as a catalyst in the absorption of atomic hydrogen in steel, promoting sulfide stress cracking ssc in highstrength steels. Asme boiler and pressure vessel code, section ix welding and brazing qualifications. V arious forms of cracks, long seam weld anomalies and dents are known to be present in pipelines, which can become a safety concern over the operational life of the pipeline.
The most typical forms of cracking and seam weld anomalies are environmentally, manufacturingor operational related, such as stress corrosion cracking, corrosion fatigue cracking, hydrogen. Guidelines for developing a procedure for the weld repair of. 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. Characteristics of sulfide stress cracking of high strength pipeline. The major problem related to welding is the occurrence of crack at high temperatures during solidification. The effect of low h2s concentrations on welded steels march. This paper reports the sulfide stress corrosion cracking ssc behavior of line pipe steel investigated using the ssc test method in nace standard tmo17777, testing of metals for resistance to. Welding equipment and consumables for the pipeline industries. Vintage and newer pipelines have the capacity to plastically deform allowing local. Sulfide stress cracking domains for carbon steel pipelines. 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. It is a complex process that is not completely understood because of the variety and complexity of mechanisms that can lead to embrittlement. In year 2012 the pipeline failed suddenly by cracking along the heat affected zone of the spiral weld.