This is not the same as hydrogen embrittlement which degrades toughness at low temperatures. Appendix 8 case study assessing operating limits for c0. Cumilox possesses all these inherent characteristics of aluminaandmore. A carbon or lowalloy steel portion of a reactor system that is to be contacted with high pressure hydrogen at elevated temperatures is provided with an intermetallic, diffusion barrier layer that reduces the rate of hydrogen attack at least tenfold compared to the steel portion without the diffusion. 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 htha can cause serious damage such as decarburization and microcracking in steels exposed hydrogen at elevated temperatures and high pressure. Hightemperature hydrogen attack an overview sciencedirect. High temperature hydrogen attack metal and metallurgy.
High temperature hydrogen attack gb inspection systems ltd. Pdf dissimilar materials are welded in many industrial and manufacturing applications. Joint industry program proposal high temperature hydrogen. The other is a high temperature phenomenon, at the temperature above 200qc, known as high temperature hydrogen attack 2. This booklet discusses factors that should be considered by engineers facing problems in designing equipment for high temperature service. Risky business inspection options for mitigating high. 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. These technologies include an evaluation and development of inspection methods for detection and sizing, fitnessforservice assessment procedures, and riskbased inspection approaches. Ultrasonic techniques for detection of high temperature hydrogen attack. Detecting and quantifying high temperature hydrogen attack. High temperatures change the atomic form of hydrogen which makes it permeate. You may reuse this information not including logos free of charge in any format or. Pdf hightemperature hydrogen attack of carbon steel. In addition, the methodology used allows for a differentiation between small inclusions and htha.
The lessons learned relate to the adequacy of design margins. This second report is rr14 maintaining the integrity of process plant susceptible to high temperature hydrogen. A hightemperature hydrogen attack htha is the loss of ductility and strength of steel caused by high temperature. Preventing high temperature hydrogen attack htha this information bulletin is intended to increase awareness of a potential safety risk identified by the u. It is a complex process that is not completely understood because of the variety and complexity of mechanisms that can lead to embrittlement. This thesis is brought to you for free and open access by the graduate school at lsu digital commons.
High temperature hydrogen attack stress engineering. 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. Free hydrogen ions are produced at the cathode during the formation of iron. This invention defines a combined inspection procedure using ultrasonic techniques for detection of hydrogen attack damage in material. This paper introduces phased arrays as an additional technique for the assessment of high temperature hydrogen attack in the base meta. Htha as the name suggests is the damage to steels exposed to hydrogen at high temperature, while others. The associated reports are available free of charge from the hse website via the links below. Us5404754a ultrasonic detection of high temperature. This micrograph shows intergranular cracking caused by high temperature hydrogen attack in a c0. The fundamentals of high temperature hydrogen attack htha. 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 microcracking. 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. The initial studies suggest that this is due to free carbon being present in the.
Hydrogen exists also as a free element in the atmosphere, but only to the extent of less than 1 ppm by volume. Avoiding high temperature hydrogen attack free download as pdf file. Pdf evaluation of mechanical fitness for service of high. Rr13 maintaining the integrity of process plant susceptible to high temperature hydrogen attack. 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. High temperature hydrogen attack is often misinterpreted with hydrogen stress cracking, hydrogen embrittlement, hydrogen induced cracking, hydrogen blistering, stress oriented hydrogen induced cracking etc. This thesis is brought to you for free and open access by the graduate school at. Outstanding features very high refractoriness, slag and metal corrosion resistance very high stability in oxidizing and reducing atmospheres at high. Htha high temperature hydrogen attack is a form of damage commonly observed in steels exposed to high pressure hydrogen at elevated temperatures. Risky business inspection options for mitigating high temperature hydrogen attack. Pdf effect of high temperature hydrogen attack in dissimilar.
The presence of hydrogen in industrial plants is a source of damage. Onstream inspection for high temperature hydrogen attack. Stressaccelerated high temperature hydrogen attack in a. Hydrogen reacts with the carbides in the steel, decarburizing the steel and forming methane. 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. Such damage can negatively affect tensile strength and toughness and ultimately cause failure without warning. The procedure comprises an initial scanning procedure for locating areas suspected of being damaged by hot hydrogen. Chemical safety and hazard investigation board csb attributed the catastrophic failure to damage caused by high temperature hydrogen attack htha.
The effects of high pressure, high temperature hydrogen on steel by e. High temperature hydrogen attack brimstoner materials 5 aug 11. Control of this high temperature hydrogen attack is achieved by selection of an appropriate crmo steel with 1. Evaluation of mechanical fitness for service of high temperature.
Api 941 steels for hydrogen service at elevated temperatures and pressures in petroleum refineries and petrochemical plantssee example below. Ib160 alertpreventing high temperature hydrogen attack. High temperature hydrogen attack is certainly not an unknown phenomenon in. High temperature hydrogen attack is also referred to as hot hydrogen attack or decarburization. The characteristics that make some of the stainless steels particularly useful in high temperature environments are described, and typical engineering data are. Steels for hydrogen service at elevated temperatures and. 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, high temperature. Free ionic hydrogen is more reactive than molecular hydrogen, the nonpolarcovalent compound of two hydrogen atoms. This paper discusses how joint design and welding defects resulted in the occurrence of htha below the carbon steel nelson curve. Where deterioration is attributed to wet hydrogen sulfide, hydrogen attack of high temperature, the suitability of degraded materials for continuing service must be closely monitored and or life prediction tools enhanced.
Low temperature hydrogen attack hydrogen included damage describes any of a number of. 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. Pdf a systematic study was made of the mechanical properties and the. 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. 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. High temperature sulfidic corrosion of carbon steel by hydrogen sulfide in. Comparative study of hydrogen embrittlement of three heatresistant crmo steels. Htha high temperature hydrogen attack exposed steel. One at ambient temperature is known as hydrogen embrittlement or low temperature hydrogen attack.
High temperature hydrogen attack htha application note. Hightemperature hydrogen attack journal article osti. Avoiding high temperature hydrogen attack hydrogen steel. 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. Effect of high temperature hydrogen attack in dissimilar materials. Hightemperature hydrogen attack htha corrosionpedia. 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. Evaluation of mechanical fitness for service of high temperature hydrogen. Htha can occur either in the parent material, in the weld, or in the heat affected. High temperature hydrogen attack htha cracking causes. It is not encountered in the average industrial plant because the problem usually occurs only in. A method of protecting carbon and lowalloy steels from high temperature 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. Htha occurs in an environment containing hydrogen and high temperatures, typically in low alloy steels. 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. 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. Tula another ground breaking innovative product from gb inspection systems were pleased to introduce our new patent pending transducer, tula, for htha early stage detection. This reaction results in hydrogen absorption by the carbides existing in the steel, leading to internal fissures and decarburization. It occurs in carbon and lowalloyed steels exposed for an extended period to hydrogen under high pressure and at high temperature. Since around 1960, hydrogen attack, or embrittlement, has been encountered with increasing frequency in high pressure, high purity systems. High temperature hydrogen attack htha is observed in steels exposed to high. The initial scanning procedure is a patternbased backscattering test that provides a pattern which is classified as falling within at least. A microstructurebased mechanism of cracking in high. 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.
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