Hydrogen sulfide cracking of carbon and alloy steels. Sulfide stress cracking ssc is a type of hydrogen cracking which presents a cathodic embrittlement mechanism. Large strength alloys such as nickel based alloys are less resistant to sulphide induced stress corrosion cracking when mixed with iron showing that the damages are caused by hydrogen charging the metal while the. H2s cracking are hydrogen induced cracking hic, stressoriented hydrogen. Effect of pearlite on stress corrosion cracking of carbon steel in. Control of corrosion in oil and gas production tubing. Stress corrosion cracking scc results from the combined action of three factors. Sulfide stress cracking nace mr01752002, mr0175iso. Pdf electrochemical and sulfide stress corrosion cracking. 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. The effect of low h2s concentrations on welded steels.
The specific crystal structure of metals is important, as it affects the rate at which hydrogen can diffuse and deformation mechanisms. Since h 2 s is acidic and reaction of steel produces iron sulphide and monatomic hydrogen, which may result in a number of different failure mechanism such as hydrogen derived microblisters, pitting and cracking. H 2s damage can lead to rapid and extensive damage to metals, including uniform corrosion, pitting, and stepwise cracking. Sulphide stress corrosion cracking sulphide stress cracking sscc has special importance in gas and oil industry, as the materials being processed there natural gas and crude oil often contain considerable amount of hydrogen sulphide. Stress corrosion cracking scc or called as environmentally assisted cracking eac may take place at the electrochemical potential range. As we know that both form of cracking are due to the absorption of atomic hydrogen that.
During investigation many cracks were observed on the inner surface of the valve body grown from the. Corrosion testing lab services,hydrogen induced disbonding laboratory,stress corrosion testing lab as per astm,nace standards. Hardness, yield strength, stress and microstructure were the primary metallurgical variables studied. Corrosionpedia what is sulfide stress cracking ssc. 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. From the chemical composition point of view, corrosion resistant nickel based alloys are categorized as pure nickel, nickelcopper alloys, nickelmolybdenum alloys, nicrmo alloys and nicrfemo alloys. Stress corrosion cracking facts and how to reduce the. Wet h2s cracking occurs due to the effects of aqueous hydrogen charging of steel in. It should not be confused with the term stress corrosion cracking which is an anodic cracking mechanism.
The relationship between hydrogen permeation and sulfide. Sulphide stress corrosion is a key issue in the petroleum and petrochemical industry because of availability of hydrogen sulphide. The laboratory critical constants were found to be lower. Stress corrosion cracking international institute of. Recommended corrosion resistant alloys for oil and gas wells. The electrochemical and sulfide stress corrosion cracking sscc. Hydrogen induced cracking hydrogen induced cracking hic when corrosion of steel occurs in an acid solution e. Amine corrosion and amine cracking of api 5l x52 carbon.
Hydrogen stress cracking occurs when hydrogen penetrates highstrength or hardened metal in a state of tensile stress. Sulphide stress cracking, ssc hydrogen induced cracking, hic erosion corrosion corrosion resistant alloys cra. Sulfide stress cracking is prevented by minimizing the hardness and strength of the. Hydrogen sulphide gas is a poisonous gas and cannot be emitted into the environment without treatment, thus hydrogen sulphide cracking process has. Hic may occasionally be delayed beyond the normal timescale of a few hours to a day, to allow for the diffusive migration of hydrogen into and, if. Hydrogen sulphide stress corrosion cracking in materials. Sulfide stress corrosion cracking of steels corrosion. Wet hydrogen sulfide h2s cracking inspectioneering. Other factors, such as ph, chloride concentration, and temperature also affect the potential for steel cracking. These are the contribution to more catastrophic failure of sulphide stress corrosion cracking in susceptible metals and alloys.
In susceptible alloys, the hydrogen combines with carbon within the alloy and forms methane. Corrosion of metal and concrete is a major issue associated with the generation and oxidation of hydrogen sulfide. Pdf sulfide stress corrosion cracking and hydrogen. For this reason, along with toxicity risks of hydrogen sulfide gas, it is essential that water muds be kept entirely free of soluble sulfides and especially hydrogen sulfide at low ph. 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. Corrosion testing lab,stress corrosion,materials,hydrogen. It should not be confused with the term stress corrosion cracking which is an. Hydrogen sulphide stress corrosion cracking in materials for. Wet h 2 s corrosion can be a particularly dangerous form of corrosion because damage. Hic steel hydrogen induced cracking supplier company. Susceptible alloys, especially steels, react with hydrogen sulfide, forming metal sulfides and atomic hydrogen as corrosion byproducts. Tests include stress corrosion cracking scc,hydrogen induced cracking test hic, sulfide stress corrosion cracking sscc, intergranular corrosion igc and sulfide stress corrosion cracking sscc at elevated. The results showed that the resistance to sscc of this joint improved first then decline after 98h aging treatments. Sulfide stress cracking is also called hydrogen sulfide cracking, sulfide cracking, sulfide corrosion cracking and sulfide stresscorrosion cracking.
This is a type of deterioration which can be linked to corrosion and corrosioncontrol processes. Carbon steel in anhydrous ammonia can suffer from scc stress corrosion cracking. Hydrogen induced cracking hic occurs when carbon steel is exposed to hydrogen sulphide h2s and is the direct result of electrochemical corrosion reactions between the sour service or wet h2s environment. It is a complex process that is not completely understood because of the variety and complexity of mechanisms that can lead to embrittlement. This type of failure is known as stress corrosion cracking, often abbreviated to scc. 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. Internal stress corrosion cracking of shale gas flowlines. Sulfide stress cracking ssc is a form of hydrogen embrittlement which is a cathodic cracking mechanism. These cracks, if undetected, can lead to failure of the pipeline. Hydrogen sulfide corrosion of carbon and stainless steel alloys in mixtures of renewable fuel sources under coprocessing conditions article pdf available in modern applied science 124. If the presence of hydrogen sulfide causes entry of hydrogen into the component, the cracking phenomenon is often termed sulphide stress cracking ssc the use of cathodic protection for corrosion protection if the process is not properly controlled. Sulfide stress cracking ssc vs hydrogen induced cracking hlc posted in refining, hydrocarbons, oil, and gas.
In this situation, cracking failures can often be thought of as a type of stress corrosion cracking. Zhang et al 2011 studied the ability of sulfur to accelerate the corrosion of carbon steel in wet h2s environments, showing that sulfur severely accelerated ssc. While these metals may normally be ductile in nature, the presence of hydrogen in a corroded environment can cause it to crack. Once molecular hydrogen is formed it cannot diffuse through the metal. Hydrogen sulfide is a chemical compound with the formula h 2 s, and is often a colorless gas with a rotten egg odor, commonly referred to as sewer gas. The valve body alloy was a216wcc cast carbon steel. 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.
Electrochemical and sulfide stress corrosion cracking behaviors of. Effect of carbon migration on sulfide stress corrosion. 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 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. Basically, stress corrosion cracking susceptibility is a function of hydrogen. Another variant of hydrogenrelated corrosive damage sulphide stress corrosion cracking affects high strength steels, in which hydrogen migrates to a crack formed on the steels surface. 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 sulfide stress corrosion cracking in materials. In the case of carbon and low alloy steels, two main forms of hydrogen embrittlement can be distinguished.
Hydrogen sulfide is particularly dangerous to equipment when moisture is present. Carbon and low alloy steels co2 corrosion general and localized. Sulfide stress cracking ssc vs hydrogen induced cracking. The hydrogen sulfide h 2 s concentration in the gas can reach 80 ppm but is usually stress corrosion cracking of carbon steel welds in amine service, corrosion 86, paper no. 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. 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. Effect of niobium on sulfide stress cracking behavior of tempered. Pdf hydrogen sulfide corrosion of carbon and stainless. If the presence of hydrogen sulphide causes entry of hydrogen into the component, the cracking phenomenon is often termed sulphide stress cracking ssc. In this paper, mechanical performance test, slow strain rate test ssrt and optical microscopy analysis were employed in studying the effect of carbon migration on sulfide stress corrosion cracking sscc behaviors of cr5moa3020cr18ni9 dissimilar joints. Stress corrosion cracking behavior of nickel base alloys. Hydrogen sulfide is a colorless, very poisonous, flammable gas with the characteristic foul odor of rotten eggs.
Sulfide stress cracking an overview sciencedirect topics. The effects of sulfide stress cracking on the mechanical properties. This term should not be confused with stress corrosion cracking scs, since this is anodic in nature. Environmental cracking of stainless and nibase alloys hydrogen sulfide corrosion acidic environments. In h 2 s containing solutions, hac is referred to as sulphide stress cracking ssc, an acronym traditionally used in the international standards dedicated to the oil and gas industry. Hydrogen sulphide these corrosion data are mainly based on results of general corrosion laboratory tests, carried out with pure chemicals and water solutions nearly saturated with air the corrosion rate can be quite different if the solution is free from oxygen. How corrosion happens in oil and gas industry aong website. A corrosive medium especially chloridebearing or hydrogensulphide h 2 s media. Hydrogen sulfide h 2s is a colorless, flammable, and extremely hazardous gas with a strong rotten egg odor. Sulphide stress cracking ssc corrosion in environments containing hydrogen sulphide can cause hydrogen absorption and cracking. The need for more adequate engineering data and a better theoretical understanding of sulfide cracking has led to a more thorough study of several variables involved in the sulfide cracking of carbon steel.
It can occur when carbonsteel equipment becomes exposed to wet h 2 s service environments, and it can come in several different forms. Abstract the sulfide saws cracking susceptibility of high strength steels used for oil grade tubulars gctg was found to correlate with the hydrogen concentration inside the metal, in equilibrium with the h 2 s saturated solution at different tempe. There are maximum acceptable h 2 s concentration limits in sale quality oil and gas. It has also been suggested that a documented example of cracking in high strength steel legs of jackup rigs was associated with hydrogeninduced stress corrosion cracking, the hydrogen being generated by the cathodic protection system operating in hydrogen sulphide contaminated seawater february 1989 issue of veritec offshore technology journal. Hydrogeninduced cracking an overview sciencedirect topics. Hydrogen sulfide hsub 2s has long been associated with the cause of corrosion damage and sulfide stress cracking ssc in high strength steels and high hardness weldments used in oil and gas production, petroleum refining, and petrochemicalchemical processing. In this research, stress corrosion cracking scc and corrosion behaviour of api 5l x52 carbon steel in 25 wt% diethanolamine solution, saturatedunsaturated with carbon dioxide and containing 0 and 200 ppm hydrogen sulphide at different temperatures were investigated using slow strain rate test, electrochemical measurement and microscopic analysis. Stresscorrosion cracking scc is a term used to describe service failures in engineering materials that occur by slow, environmentally induced crack propagation. H 2 s can cause corrosion of stainless steels such as 316 and 410 stainless in the form of sulfide stress cracking. Alloys for offshore applications duplex and super duplex.
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