High temperature hydrogen attack htha application note. High temperature hydrogen attack htha european federation of. The characteristics that make some of the stainless steels particularly useful in hightemperature environments are described, and typical engineering data are. This paper discusses how joint design and welding defects resulted in the occurrence of htha below the carbon steel nelson curve. This form of hydrogen damage is called high temperature hydrogen attack htha, and this recommended practice discusses the resistance of steels to htha. Preventing high temperature hydrogen attack htha this information bulletin is intended to increase awareness of a potential safety risk identified by the u. Chris jones quest integrity, charles thomas quest integrity, and david keen incitec pivot limited as seen in the september october issue of world fertilizer magazine.
It occurs in carbon and lowalloyed steels exposed for an extended period to hydrogen under high pressure and at high temperature. In the oil and gas industry, high temperature hydrogen attack htha can occur in steel operating at high temperature, usually above 205c 400f. High temperature hydrogen attack htha cracking causes. Steels for hydrogen service at elevated temperatures and. Such damage can negatively affect tensile strength and toughness and ultimately cause failure without warning. Very high concentrations of naphthenic acids tan required for the onset naphthenic acid corrosion.
Hydrogen reacts with the carbides in the steel, decarburizing the steel and forming methane gas bubbles at the grain boundaries with no loss of thickness. High temperature hydrogen attack htha can cause serious damage such as decarburization and microcracking in steels exposed hydrogen at elevated temperatures and high pressure. Should hydrogen attack damage be identified, the velocity ratio and spectrum analysis tests can then be used to determine mechanical properties of the hydrogen attack damaged material. This micrograph shows intergranular cracking caused by high temperature hydrogen attack in a c0. High temperature hydrogen attack htha is a damage mechanism that has the potential to cause catastrophic failure of low alloy steel processing plant. How to assess the susceptibility of an alloy steel to high temperature hydrogen attack htha. This paper introduces phased arrays as an additional technique for the assessment of high temperature hydrogen attack in the base meta. Pdf a systematic study was made of the mechanical properties and the microscopic fracture processes associated with hydrogen attack of. Hightemperature exposure of the carbon and lowalloy steels used for piping and pressure vessels in highpressure hydrogen service leads to a special form of degradation known as htha, sometimes called hydrogen attack.
High temperature hydrogen attack blacksmith37 materials 10 aug 11 15. Hightemperature sulfidic corrosion of carbon steel by hydrogen sulfide in. Within the refinery and chemicals industries, high temperature hydrogen attack htha continues to be a processsafety issue. High temperature hydrogen attack htha, also called hot hydrogen attack, is a problem which concerns steels operating at elevated temperatures typically above 400c in hydrogen environments, in refinery, petrochemical and other chemical facilities and, possibly, high pressure steam boilers. Stressaccelerated high temperature hydrogen attack in a. High temperatures change the atomic form of hydrogen which makes it permeate into the steel, react with carbon, and form methane. Detecting and quantifying high temperature hydrogen attack htha. Control of this hightemperature hydrogen attack is achieved by selection of an appropriate crmo steel with 1. High temperature hydrogen attack htha of steels plagues higher temperature industrial applications, especially in the petrochemical industry, due to the lack of a mechanistic understanding of the phenomenon and the use of empirically established design criteria, such as the nelson curves. The kinetics of hydrogen attack of a killed steel have been studied in the temperaturerange 800 to 1200 f and in the pressure range 450 to 950 psi hydrogen. High temperature hydrogen attack htha, also called hot hydrogen attack, is a problem which affects steels operating at elevated temperatures in hydrogen environments, in refinery, petrochemical and other chemical facilities and, possibly, high pressure steam boilers. Detecting and quantifying high temperature hydrogen attack. These technologies include an evaluation and development of inspection methods for detection and sizing, fitnessforservice assessment procedures, and riskbased inspection approaches.
For a given exposure time, hydrogen attack of steel starts at a limiting temperature and. Hydrogen present in metals can produce several kinds of internal defects like blisters, shatter fracture, flakes, fisheyes and porosity. Carbon steels exposed to hydrogen at high temperatures experience hydrogen attack which leads to internal decarburization and weakening. This is not the same as hydrogen embrittlement which degrades toughness at low temperatures. What is high temperature hydrogen attack hthahot hydrogen. Ndt high temperature hydrogen attack tuv rheinland. Htha can occur either in the parent material, in the weld, or in the heat affected. Hightemperature sulfidic corrosion of carbon steel by hydrogen sulfide in hydrogenrich streams occurs at temperatures above 230 c.
Provided these parameters are not so high as to lead to hydrogen attack, there are no problems at elevated temperature, because steel is not embrittled by. This second report is rr14 maintaining the integrity of process plant susceptible to high temperature hydrogen. High temperature hydrogen attack htha inspectioneering. High temperatures change the atomic form of hydrogen which makes it permeate.
High temperature hydrogen attack is also referred to as hot hydrogen attack or decarburization. Joint industry program proposal high temperature hydrogen. Fissuring and cracking caused by internal methane pressure. E2g high temperature hydrogen attack joint industry program. A systematic study was made of the mechanical properties and the microscopic fracture processes associated with hydrogen attack of sae 1020 carbon steel in a wellcontrolled, hightemperature, highpurity hydrogen environment. Understanding of the high temperature hydrogen attack htha high temperature hydrogen attack htha is an irreversible deterioration of the mechanical properties of steel due to the reaction of hydrogen with carbon at temperatures in excess of 200 c. Decarburisation caused by the reaction between carbon as carbide and dissolved hydrogen to form methane. Risky business inspection options for mitigating high temperature hydrogen attack. Htha hydrogen attack htha high temperature hydrogen attack is a form of damage commonly observed in steels exposed to high pressure hydrogen at elevated temperatures. At standard temperature and pressure conditions, it is a colourless, odourless, tasteless, nontoxic, noncorrosive, nonmetallic diatomic gas, which is in principle physiologically not dangerous. This is the second of two reports on maintaining the integrity of process plant operating in high temperature hydrogen service. Ultrasonic techniques for detection of high temperature hydrogen attack. Low temperature hydrogen attack hydrogen included damage describes any of a number of. Hydrogen damage is the generic name given to a large number of metal degradation processes due to interaction with hydrogen hydrogen is present practically everywhere, several kilometres above the earth and inside the earth.
This is the first of two reports on maintaining the integrity of process plant operating in high temperature hydrogen service. At elevated temperatures, molecular hydrogen dissociates into the atomic form, which can readily enter and diffuse through steel. For many years the sccm task group on high temperature hydrogen attack htha has maintained refining industry data on htha, and developed guidelines to deal with it reference. Effect of high temperature hydrogen attack in dissimilar materials. Hydrogen attack occurs when hydrogen is contained under high. Htha occurs in an environment containing hydrogen and high temperatures, typically in low alloy steels. The procedure comprises an initial scanning procedure for locating areas suspected of being damaged by hot hydrogen. The damage occurs as hydrogen atoms diffuse into steels, react with carbon, form methane gas internally in the material, which results in decarburization and fissuring. The fundamentals of high temperature hydrogen attack htha.
Hydrogen diffuses through the steel and reacts with carbon to form methane which builds up. High temperature hydrogen attack gb inspection systems ltd. Micromechanics of high temperature hydrogen attack sabine m. In addition, the methodology used allows for a differentiation between small inclusions and htha. The initial scanning procedure is a patternbased backscattering test that provides a pattern which is classified as falling within at least. One at ambient temperature is known as hydrogen embrittlement or low temperature hydrogen attack. High temperature hydrogen attack htha is a phenomenon which occurs within some industrial processes when the presence of hydrogen, subjected to high temperature and pressure, makes plants and systems. Under the prevailing temperature and hydrogen partial pressure shown in figure 1 above, 1cr0. The amount of hydrogen absorbed increases with the partial pressure of hydrogen and the temperature fig.
High temperature hydrogen attack htha is a phenomenon which occurs within some industrial processes when the presence of hydrogen, subjected to high temperature and pressure, makes plants and systems susceptible to damage. Hydrogen can be considered an ideal gas over a wide temperature range and even at high pressures. The presence of hydrogen in industrial plants is a source of damage. The kinetics of hydrogen attack of a killed steel have been studied in the temperature range 800 to 1200 f and in the pressure range 450 to 950 psi hydrogen. Dissolution of hydrogen from the process environment. Hydrogen attack is one of the major problems in refineries, where hydrogen and hydrocarbon streams are handled up to 20 mpa and approximately 810k level. High temperature hydrogen attack metal and metallurgy. High temperature hydrogen attack htha learn more about our latest ondemand webinar. High temperature hydrogen attack htha in the petrochemical is caused when the hydrogen from the stream seeps into carbon and low alloy steels at high temperatures. When steel is exposed to atomic hydrogen at high temperatures and pressures, hydrogen atoms may dissolve into methane, accumulating in bubbles that connect to create microfissures at steel grain boundaries. High temperature hydrogen attack the damage mechanism that leads to htha is. Htha is a damage mechanism that results in fissures and cracking and occurs when carbon steel equipment is exposed to hydrogen at high temperatures and. It is the result of hydrogen disassociating and dissolving in the. The term shall commence on the effective date november 15, 2012 following the completion of existing project and agreement that e2g contractor htha jip shall commence and continue for an initial period of two years unless.
Onstream inspection for high temperature hydrogen attack. Hightemperature hydrogen attack is also referred to as hot hydrogen attack or decarburization. Detecting and assessing htha inspection challenges. Kinetics and mechanism of hydrogen attack of steel corrosion. Appendix 8 case study assessing operating limits for c0.
This reaction results in hydrogen absorption by the carbides existing in the steel, leading to internal fissures and decarburization. Hydrogen reacts with the carbides in the steel, decarburizing the steel and forming methane. Micromechanics, fracture, creep, hydrogen abstract. High temperature hydrogen attack stress engineering. Risk analysis for high temperature hydrogen attack charles thomas quest integrity group limited lower hutt, new zealand high temperature hydrogen attack htha is a damage mechanism that has the potential to cause catastrophic failure of low alloy steel processing plant. Hightemperature hydrogen attack of carbon steel springerlink. A systematic study was made of the mechanical properties and the microscopic fracture processes associated with hydrogen attack of sae 1020 carbon steel in a wellcontrolled, high temperature. Ib160 alertpreventing high temperature hydrogen attack. This selective leaching process is known as hydrogen attack, or high temperature hydrogen attack, and leads to decarburization of the steel and loss of strength and ductility. High temperature hydrogen attack htha is one such form of degradation which is due to the formation of methane ch4 by reaction with carbides in steel. A systematic study was made of the mechanical properties and the microscopic fracture processes associated with hydrogen attack of sae 1020 carbon steel in a wellcontrolled, hightemperature. The approach is based on backscattering spectrum analysis provided by 0 probe for parent metal and by tofd ut for weld inspection at high temperature. This booklet discusses factors that should be considered by engineers facing problems in designing equipment for hightemperature service. Htha high temperature hydrogen attack exposed steel.
Factors that determine the degree of attack are temperature, hydrogen partial pressure, stress, exposure time, composition of the stee. Pdf hightemperature hydrogen attack of carbon steel. This first report is rr13maintaining the integrity of process susceptible to plant high temperature hydrogen attack. Hydrogen attack, detection, assessment and evaluation. This invention defines a combined inspection procedure using ultrasonic techniques for detection of hydrogen attack damage in material. Risky business inspection options for mitigating high. Such behaviour is surprising even for 9% cr1% mo steel. Risk analysis for high temperature hydrogen attack quest integrity. High temperature hydrogen attack htha is an intergranular damage mechanism that can occur in process equipment that is exposed to hydrogen at elevated temperatures at least 400 o f or 204 o c, under dry conditions, when hydrogen disassociates into nascent atomic hydrogen, which is then driven into the steel by the temperature and pressure of the environment. Pdf effect of high temperature hydrogen attack in dissimilar.
Us5404754a ultrasonic detection of high temperature. How to select alloy steels for high temperature hydrogen services. A hightemperature hydrogen attack htha is the loss of ductility and strength of steel caused by high temperature. This methane does not diffuse out of the metal, and collects in the voids at high pressure and initiates cracks in the steel. Engineering materials are exposed to hydrogen and they may interact with it resulting in various kinds of structural damage. The other is a high temperature phenomenon, at the temperature above 200qc, known as high temperature hydrogen attack 2. A microstructurebased mechanism of cracking in high. Pdf 2d6 automatic detection of high temperature hydrogen. A quantitative relationship between incubation of attack and temperature and pressure has been obtained. High temperature exposure of the carbon and lowalloy steels used for piping and pressure vessels in high pressure hydrogen service leads to a special form of degradation known as htha, sometimes called hydrogen attack. Stress engineering services ses has observed a growing industry need for htha damage assessments for asset prioritization and capital planning, and has developed two new htha damage life assessment methods. Hydrogen embrittlement an overview sciencedirect topics. High temperature hydrogen attack htha is an insidious condition that can occur in process equipment exposed to hydrogen at elevated temperatures at least 400f or 204c, under dry conditions, when hydrogen disassociates into nascent atomic hydrogen, which is then driven into the steel by the temperature and pressure of the environment. The effects of highpressure, hightemperature hydrogen on steel by e.
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