Duplex stainless steels are a family of stainless steels. Named duplex (or austenitic-ferritic) grades because their metallurgical structure consists of two phases, austenite, and ferrite in approximately equal proportions. They are expected to provide better corrosion resistance, particularly chloride stress corrosion and chloride pitting corrosion, and higher strength than standard austenitic stainless steels such as Type 304 or 316. They are therefore used extensively in the offshore oil and gas and in the petrochemical industry in the form of piping and pressure vessels. This paper describes some applications that ended up in failures and the importance to adhere to tight fabrications fabrication controls and consider the effect of common manufacturing and fabrication deviations in the expected material performance. The first one is a shell and tube heat exchanger. On the shell side the material choice was 2205 duplex stainless steel. The shell side fluid is fed from debutanizer which feeds from upstream high pressure and low-pressure low temperature separators. Overhead stream contains H2S, NH3, HCl. The duplex was selected for this exchanger to mitigate potential dew point NH4Cl corrosion. The shell ended up leaking in less than two years after being placed in service. The second case is a super duplex 2507 seawater filter which failed after few weeks in service. Qualified welding procedures were not properly followed during fabrication leading to impaired corrosion resistant weldments. The third case describes one more failure of a hydrocracker reactor effluent air cooler. Tube to tubesheet and partition plates to tubesheet welds failed after ∼ 20 years in service.
{"title":"Duplex Stainless Steel – Learning From Field Experience in Oil & Gas and Petrochemical Services","authors":"M. Dalal, J. Penso","doi":"10.1115/pvp2022-84889","DOIUrl":"https://doi.org/10.1115/pvp2022-84889","url":null,"abstract":"\u0000 Duplex stainless steels are a family of stainless steels. Named duplex (or austenitic-ferritic) grades because their metallurgical structure consists of two phases, austenite, and ferrite in approximately equal proportions. They are expected to provide better corrosion resistance, particularly chloride stress corrosion and chloride pitting corrosion, and higher strength than standard austenitic stainless steels such as Type 304 or 316. They are therefore used extensively in the offshore oil and gas and in the petrochemical industry in the form of piping and pressure vessels.\u0000 This paper describes some applications that ended up in failures and the importance to adhere to tight fabrications fabrication controls and consider the effect of common manufacturing and fabrication deviations in the expected material performance. The first one is a shell and tube heat exchanger. On the shell side the material choice was 2205 duplex stainless steel. The shell side fluid is fed from debutanizer which feeds from upstream high pressure and low-pressure low temperature separators. Overhead stream contains H2S, NH3, HCl. The duplex was selected for this exchanger to mitigate potential dew point NH4Cl corrosion. The shell ended up leaking in less than two years after being placed in service.\u0000 The second case is a super duplex 2507 seawater filter which failed after few weeks in service. Qualified welding procedures were not properly followed during fabrication leading to impaired corrosion resistant weldments.\u0000 The third case describes one more failure of a hydrocracker reactor effluent air cooler. Tube to tubesheet and partition plates to tubesheet welds failed after ∼ 20 years in service.","PeriodicalId":434862,"journal":{"name":"Volume 4B: Materials and Fabrication","volume":"405 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122790299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
There is enthusiasm for new civil nuclear plants in the UK to adopt power beam welding technologies, which could offer several advantages over conventional techniques. In particular, reduction in the time taken to produce and inspect a weld, and thus the cost of manufacturing components. However, a blocker to the adoption of these technologies is a shortage of accepted methodologies for demonstrating the integrity of these joints, which forms part of the requirements of the generic design assessment within the UK regulatory environment. Residual stresses can contribute towards crack driving force and thus should be accounted for when assessing the integrity of a component or its tolerance to damage. Whilst bounding residual stress fields are often used, it is often desirable to have more realistic estimations that capture the through-wall residual stress distribution, which also allows them to be decomposed into membrane, bending and self-equilibrated components to aid stress classification. Material-specific weld residual stress profiles already exist, for example Level 3 profiles in the UK’s R6 procedure. However, they are for arc welding techniques. This work seeks to provide a framework for the generation of weld residual stress profiles for power beam welds and is split over two papers: 1. Weld Production, Residual Stress Measurements and Predictions; 2. A Methodology and Example for Parameterised Residual Stress Profiles. In this paper, the second in this series, a framework is presented for producing parametric through-thickness weld residual stress profiles using the validated modelling from the first paper in the series.
{"title":"Electron Beam Welds in 316L Part 2: A Methodology and Example for Parameterised Residual Stress Profiles","authors":"G. Horne, B. Elliott, Andrew Moffat","doi":"10.1115/pvp2022-84798","DOIUrl":"https://doi.org/10.1115/pvp2022-84798","url":null,"abstract":"\u0000 There is enthusiasm for new civil nuclear plants in the UK to adopt power beam welding technologies, which could offer several advantages over conventional techniques. In particular, reduction in the time taken to produce and inspect a weld, and thus the cost of manufacturing components. However, a blocker to the adoption of these technologies is a shortage of accepted methodologies for demonstrating the integrity of these joints, which forms part of the requirements of the generic design assessment within the UK regulatory environment.\u0000 Residual stresses can contribute towards crack driving force and thus should be accounted for when assessing the integrity of a component or its tolerance to damage. Whilst bounding residual stress fields are often used, it is often desirable to have more realistic estimations that capture the through-wall residual stress distribution, which also allows them to be decomposed into membrane, bending and self-equilibrated components to aid stress classification.\u0000 Material-specific weld residual stress profiles already exist, for example Level 3 profiles in the UK’s R6 procedure. However, they are for arc welding techniques. This work seeks to provide a framework for the generation of weld residual stress profiles for power beam welds and is split over two papers:\u0000 1. Weld Production, Residual Stress Measurements and Predictions;\u0000 2. A Methodology and Example for Parameterised Residual Stress Profiles.\u0000 In this paper, the second in this series, a framework is presented for producing parametric through-thickness weld residual stress profiles using the validated modelling from the first paper in the series.","PeriodicalId":434862,"journal":{"name":"Volume 4B: Materials and Fabrication","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123062300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
IN718 is a precipitation hardened nickel-based superalloy, which is well known for its high strength, good corrosion and creep resistance from low to high temperatures. It is therefore a popular material for numerous applications. Nevertheless, it is known that hydrogen can strongly affect the mechanical properties of IN718. Some questions still need to be clarified to ensure the safe use of components in a hydrogen environment. In this work, the hydrogen uptake in a gaseous hydrogen environment and tensile and fatigue properties of pre-charged IN718 were investigated. Specimen were charged at 350°C and 100 bar hydrogen pressure. It turned out, that saturation was reached after 10 days with a hydrogen content of about 27 wppm. Tensile tests showed a loss of elongation to failure and reduction of area for the pre-charged specimen. Hydrogen effects were also evident in the low cycle fatigue test. The cycles to failure were significantly reduced. Investigations of the fracture surfaces showed clear differences in crack growth of non-charged and pre-charged tensile and fatigue specimen.
{"title":"Gaseous Hydrogen Charging and Fatigue Testing on IN718","authors":"Fabien Ebling, K. Wackermann","doi":"10.1115/pvp2022-84184","DOIUrl":"https://doi.org/10.1115/pvp2022-84184","url":null,"abstract":"\u0000 IN718 is a precipitation hardened nickel-based superalloy, which is well known for its high strength, good corrosion and creep resistance from low to high temperatures. It is therefore a popular material for numerous applications. Nevertheless, it is known that hydrogen can strongly affect the mechanical properties of IN718. Some questions still need to be clarified to ensure the safe use of components in a hydrogen environment.\u0000 In this work, the hydrogen uptake in a gaseous hydrogen environment and tensile and fatigue properties of pre-charged IN718 were investigated. Specimen were charged at 350°C and 100 bar hydrogen pressure. It turned out, that saturation was reached after 10 days with a hydrogen content of about 27 wppm. Tensile tests showed a loss of elongation to failure and reduction of area for the pre-charged specimen. Hydrogen effects were also evident in the low cycle fatigue test. The cycles to failure were significantly reduced. Investigations of the fracture surfaces showed clear differences in crack growth of non-charged and pre-charged tensile and fatigue specimen.","PeriodicalId":434862,"journal":{"name":"Volume 4B: Materials and Fabrication","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127693360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
May L. Martin, P. Bradley, D. Lauria, R. Amaro, M. Connolly, A. Slifka
Strain-life testing of a 4130 pressure vessel steel was conducted in air and in a high-pressure gaseous-hydrogen environment. Hydrogen causes an order of magnitude decrease in lifetime compared to in-air performance at the same strain-amplitudes. This decrease in lifetime in hydrogen is accompanied by various effects, such as a shift in the cyclic stress-strain curve, different influences on the elastic and plastic components of the strain-life data, and a distinct difference in the evolution of the microstructural texture prior to failure. For comparison, preliminary data from testing of a higher strength pressure vessel steel is presented, showing a difference in elastic/plastic partitioning may be accompanied by a difference in reduction in lifetime due to hydrogen.
{"title":"Strain-Life Performance in Hydrogen of a Dot Pressure Vessel Steel","authors":"May L. Martin, P. Bradley, D. Lauria, R. Amaro, M. Connolly, A. Slifka","doi":"10.1115/pvp2022-81492","DOIUrl":"https://doi.org/10.1115/pvp2022-81492","url":null,"abstract":"\u0000 Strain-life testing of a 4130 pressure vessel steel was conducted in air and in a high-pressure gaseous-hydrogen environment. Hydrogen causes an order of magnitude decrease in lifetime compared to in-air performance at the same strain-amplitudes. This decrease in lifetime in hydrogen is accompanied by various effects, such as a shift in the cyclic stress-strain curve, different influences on the elastic and plastic components of the strain-life data, and a distinct difference in the evolution of the microstructural texture prior to failure. For comparison, preliminary data from testing of a higher strength pressure vessel steel is presented, showing a difference in elastic/plastic partitioning may be accompanied by a difference in reduction in lifetime due to hydrogen.","PeriodicalId":434862,"journal":{"name":"Volume 4B: Materials and Fabrication","volume":"146 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121963441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The main degradation mechanism of NPP’s components is radiation damage, but these processes are situated only in the core region of the reactor pressure vessel (RPV). The main mechanical loading of all individual parts of NPP’s primary circuit are the influence of high pressure at elevated temperature till 300°C. These processes lead to the fatigue damage of structural materials, which is characterized as the thermal fatigue or thermal ageing. The decommissioning of two V1 units in Slovakia provides a great opportunity to preserve materials from equipment that was in conditions of real operation for decades (app. 28–29 campaigns). VUJE, in cooperation with other partners, prepared necessary steps to create a material archive and related database including all relevant information from the decommissioned units of WWER-440 reactors. The main goal is to evaluate the real influence of long-term operation (LTO) on the degradation of NPP parts, such as steam-generators (SGs). The Small Punch Test (SPT) methods are mainly used for evaluation of materials actual state. By the SPT technique it is possible to evaluate the basic tensile properties as the ultimate tensile strength and the yield stress of the tested materials from a very small amount of obtained material. The paper deals with description of special sampling from steam generators of operating units in Slovakia and subsequent testing of samples taken by the SPT method. All these results were compared with reference testing on materials taken from decommissioned V1 NPP.
{"title":"Application of Small Punch Testing Methods for Thermal Ageing Assessment at Steam-Generators Materials From Decommissioned V1 NPP to LTO Support on VVER Type Units in Slovakia","authors":"J. Petzová, M. Adamech, Dávid Slnek","doi":"10.1115/pvp2022-83875","DOIUrl":"https://doi.org/10.1115/pvp2022-83875","url":null,"abstract":"\u0000 The main degradation mechanism of NPP’s components is radiation damage, but these processes are situated only in the core region of the reactor pressure vessel (RPV). The main mechanical loading of all individual parts of NPP’s primary circuit are the influence of high pressure at elevated temperature till 300°C. These processes lead to the fatigue damage of structural materials, which is characterized as the thermal fatigue or thermal ageing. The decommissioning of two V1 units in Slovakia provides a great opportunity to preserve materials from equipment that was in conditions of real operation for decades (app. 28–29 campaigns). VUJE, in cooperation with other partners, prepared necessary steps to create a material archive and related database including all relevant information from the decommissioned units of WWER-440 reactors. The main goal is to evaluate the real influence of long-term operation (LTO) on the degradation of NPP parts, such as steam-generators (SGs).\u0000 The Small Punch Test (SPT) methods are mainly used for evaluation of materials actual state. By the SPT technique it is possible to evaluate the basic tensile properties as the ultimate tensile strength and the yield stress of the tested materials from a very small amount of obtained material. The paper deals with description of special sampling from steam generators of operating units in Slovakia and subsequent testing of samples taken by the SPT method. All these results were compared with reference testing on materials taken from decommissioned V1 NPP.","PeriodicalId":434862,"journal":{"name":"Volume 4B: Materials and Fabrication","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131349750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
High strength steels are increasingly being used in applications such as ship hulls and oil and gas pipelines which are subjected to corrosive environment. These steel grades exhibit more than an order of magnitude higher crack growth rates in corrosive environments compared with the crack growth rates in air. A mathematical model is developed based on the slip dissolution mechanism to evaluate the chemistry and potential distributions in the occluded crack. The species distribution due to diffusion and ion migration is evaluated by considering the effect of ferrous hydroxide formation on the transport properties in the electrolyte. It is also found that the potential and pH drop in the crack is affected by the crack tip stress and strain fields. The dissolution of iron at the crack tip is enhanced by the pH drop. Both steady state and transient numerical studies are carried out to determine the evolving crack geometry. Thus, by considering reactions inside the crack, a better representation of the species and potential distributions can be obtained.
{"title":"Modeling Electric-Potential for a Crack Subjected to Corrosion Under Static and Cyclic Loading","authors":"R. Prakash, C. Anish, D. Sampath","doi":"10.1115/pvp2022-85773","DOIUrl":"https://doi.org/10.1115/pvp2022-85773","url":null,"abstract":"\u0000 High strength steels are increasingly being used in applications such as ship hulls and oil and gas pipelines which are subjected to corrosive environment. These steel grades exhibit more than an order of magnitude higher crack growth rates in corrosive environments compared with the crack growth rates in air. A mathematical model is developed based on the slip dissolution mechanism to evaluate the chemistry and potential distributions in the occluded crack. The species distribution due to diffusion and ion migration is evaluated by considering the effect of ferrous hydroxide formation on the transport properties in the electrolyte. It is also found that the potential and pH drop in the crack is affected by the crack tip stress and strain fields. The dissolution of iron at the crack tip is enhanced by the pH drop. Both steady state and transient numerical studies are carried out to determine the evolving crack geometry. Thus, by considering reactions inside the crack, a better representation of the species and potential distributions can be obtained.","PeriodicalId":434862,"journal":{"name":"Volume 4B: Materials and Fabrication","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114124547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Laura Andrea Calvo, Borja Arroyo Martínez, J.A. Alvarez Laso, F. Gutiérrez-Solana, Sergio Cicero González, Roberto Lacalle Calderón
The Small Punch Test is a recently standardized technique successfully employed for estimating the tensile, creep and fracture properties of metallic materials, and is considered as one of the most suitable options for evaluating mechanical properties when materials are in shortage. Several advances have been made in order to apply this methodology for mechanical characterizations in aggressive environments. The first tests were carried out pre-embrittling the samples in environment and then testing them in air. Subsequent methodologies proposed tests in environment after pre-embrittling the samples in order not to lose part of the embrittling capacity while testing; in these scenarios the punch rate has an enormous influence on environmental characterizations. The most recent works propose to implement in the Small Punch Test the step loading methodology collected in ASTM F1624 standard, which solves these problems by applying steps at a constant load which gradually increases until the sample fails. In this work, guidelines for the application of Small Punch Tests to determine the threshold load in aggressive environment are given, based on tests results under hydrogen embrittlement scenarios. A range of punch rates for constant punch displacement is provided, together with the suitable step times when applying the step loading technique, and a correlation to estimate the threshold stress based on Small Punch samples tested with this novel technique.
{"title":"Overview of Suitable Methodologies for Threshold Stress Determination by Small Punch in Aggressive Environments","authors":"Laura Andrea Calvo, Borja Arroyo Martínez, J.A. Alvarez Laso, F. Gutiérrez-Solana, Sergio Cicero González, Roberto Lacalle Calderón","doi":"10.1115/pvp2022-84744","DOIUrl":"https://doi.org/10.1115/pvp2022-84744","url":null,"abstract":"\u0000 The Small Punch Test is a recently standardized technique successfully employed for estimating the tensile, creep and fracture properties of metallic materials, and is considered as one of the most suitable options for evaluating mechanical properties when materials are in shortage. Several advances have been made in order to apply this methodology for mechanical characterizations in aggressive environments. The first tests were carried out pre-embrittling the samples in environment and then testing them in air. Subsequent methodologies proposed tests in environment after pre-embrittling the samples in order not to lose part of the embrittling capacity while testing; in these scenarios the punch rate has an enormous influence on environmental characterizations. The most recent works propose to implement in the Small Punch Test the step loading methodology collected in ASTM F1624 standard, which solves these problems by applying steps at a constant load which gradually increases until the sample fails. In this work, guidelines for the application of Small Punch Tests to determine the threshold load in aggressive environment are given, based on tests results under hydrogen embrittlement scenarios. A range of punch rates for constant punch displacement is provided, together with the suitable step times when applying the step loading technique, and a correlation to estimate the threshold stress based on Small Punch samples tested with this novel technique.","PeriodicalId":434862,"journal":{"name":"Volume 4B: Materials and Fabrication","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114492887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Simple screening technology for hydrogen embrittlement (HE) of steels for hydrogen energy facilities using the in-situ small punch (SP) test method has been established. The HE behaviors of API X70 steel base metal and welds for pipelines were investigated using the relative reduction of thickness (RRT) obtained by the in-situ SP test. As a result, it was found that API X70 steel exhibited similar HE sensitivity regardless of test conditions and weld regions. In this study, to give data application reliability to the RRT obtained by the in-situ SP test of ferritic steels, a simple in-situ slow strain-rate tensile (SSRT) test method using a hollow-type specimen was devised. It was used to evaluate the HE sensitivity of the API X70 steel and welds at various temperatures, and the obtained relative reduction of area (RRA) was used to compare to the RRT by in-situ SP test. As a result, it can be found that RRT by in-situ SP test showed a generally good relationship with RRA by the SSRT, even though some variation existed depending on the test temperature, confirming that the in-situ SP test can be effectively applied to the HE sensitivity screening of pipeline steels and welds in high-pressure hydrogen environments.
{"title":"Development of Screening Technology for Hydrogen Embrittlement Compatibility of Pipeline Steels and Welds Using Simple In-Situ Tests in High-Pressure Environments","authors":"H. Shin, Eunsu Min, Sung-Duk Kang, U. Baek","doi":"10.1115/pvp2022-84647","DOIUrl":"https://doi.org/10.1115/pvp2022-84647","url":null,"abstract":"\u0000 Simple screening technology for hydrogen embrittlement (HE) of steels for hydrogen energy facilities using the in-situ small punch (SP) test method has been established. The HE behaviors of API X70 steel base metal and welds for pipelines were investigated using the relative reduction of thickness (RRT) obtained by the in-situ SP test. As a result, it was found that API X70 steel exhibited similar HE sensitivity regardless of test conditions and weld regions. In this study, to give data application reliability to the RRT obtained by the in-situ SP test of ferritic steels, a simple in-situ slow strain-rate tensile (SSRT) test method using a hollow-type specimen was devised. It was used to evaluate the HE sensitivity of the API X70 steel and welds at various temperatures, and the obtained relative reduction of area (RRA) was used to compare to the RRT by in-situ SP test. As a result, it can be found that RRT by in-situ SP test showed a generally good relationship with RRA by the SSRT, even though some variation existed depending on the test temperature, confirming that the in-situ SP test can be effectively applied to the HE sensitivity screening of pipeline steels and welds in high-pressure hydrogen environments.","PeriodicalId":434862,"journal":{"name":"Volume 4B: Materials and Fabrication","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124989935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A prefeed heater in a hydrotreater unit experienced a fire while being prepared for shutdown during a turnaround. The prefeed hydrotreater heater was a mixed operation heater that typically operated in mixed mode with hydrogen and hydrocarbon bitumen, but at the time of the incident was operating in hydrogen only mode in order to hot hydrogen strip the hydrotreater. The heater had been in operation since 2011 and had a design fluid temperature of 425 °C (797 °F), a tube metal temperature of 570 °C (1058 °F) and design pressure of 16,800 kPag (2437 Psig). The normal operating pressure was 15,000 kPag (2176 Psig). The radiant and convection tubes were fabricated from Type 316Nb stainless steel (UNS31640). There was a tube rupture in the radiant section that caused the fire and the subsequent failure investigation established that the temperature in the radiant section at the rupture location had reached in excess of 850 °C (1562 °F) for over a 15-minute period prior to rupturing. The following paper outlines the failure analysis and root causes which caused the incident, while detailing the recovery and construction of the heater, including the fitness-for-service methods and inspections conducted. The heater was partially rebuilt with the convection section tube material being recovered and the radiant section being rebuilt in a different metallurgy.
{"title":"Case History of Hydrotreater Prefeed Heater Fire Recovery","authors":"J. Penso, Neil Park, M. Dalal, Alexandra Hosack","doi":"10.1115/pvp2022-84863","DOIUrl":"https://doi.org/10.1115/pvp2022-84863","url":null,"abstract":"\u0000 A prefeed heater in a hydrotreater unit experienced a fire while being prepared for shutdown during a turnaround. The prefeed hydrotreater heater was a mixed operation heater that typically operated in mixed mode with hydrogen and hydrocarbon bitumen, but at the time of the incident was operating in hydrogen only mode in order to hot hydrogen strip the hydrotreater.\u0000 The heater had been in operation since 2011 and had a design fluid temperature of 425 °C (797 °F), a tube metal temperature of 570 °C (1058 °F) and design pressure of 16,800 kPag (2437 Psig). The normal operating pressure was 15,000 kPag (2176 Psig). The radiant and convection tubes were fabricated from Type 316Nb stainless steel (UNS31640). There was a tube rupture in the radiant section that caused the fire and the subsequent failure investigation established that the temperature in the radiant section at the rupture location had reached in excess of 850 °C (1562 °F) for over a 15-minute period prior to rupturing. The following paper outlines the failure analysis and root causes which caused the incident, while detailing the recovery and construction of the heater, including the fitness-for-service methods and inspections conducted. The heater was partially rebuilt with the convection section tube material being recovered and the radiant section being rebuilt in a different metallurgy.","PeriodicalId":434862,"journal":{"name":"Volume 4B: Materials and Fabrication","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128030083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Elastic modulus of 316L and XM-19 austenitic stainless steel was characterized before and after hydrogen charging using impulse excitation. Four coupons of each alloy were subsequently charged at 300 C and 138 MPa for 13 days with gaseous hydrogen to ensure an equilibrium concentration of hydrogen was achieved. Elastic modulus was re-characterized after charging. In 316L, the elastic modulus increased by 0.28% (0.546 GPa) on average on three of the samples, while one sample did not show a significant change. In XM-19, the elastic modulus increased by 0.38% (0.734 GPa) on average. The increase in both XM-19 test coupons and three 316L test coupons was statistically significant, while the increase in the other 316L test coupon was not.
{"title":"The Influence of Hydrogen on the Elastic Modulus of 316L and XM-19 Austenitic Stainless Steels","authors":"K. Scott, P. Mendez, S. Seetharaman","doi":"10.1115/pvp2022-84717","DOIUrl":"https://doi.org/10.1115/pvp2022-84717","url":null,"abstract":"\u0000 Elastic modulus of 316L and XM-19 austenitic stainless steel was characterized before and after hydrogen charging using impulse excitation. Four coupons of each alloy were subsequently charged at 300 C and 138 MPa for 13 days with gaseous hydrogen to ensure an equilibrium concentration of hydrogen was achieved. Elastic modulus was re-characterized after charging. In 316L, the elastic modulus increased by 0.28% (0.546 GPa) on average on three of the samples, while one sample did not show a significant change. In XM-19, the elastic modulus increased by 0.38% (0.734 GPa) on average. The increase in both XM-19 test coupons and three 316L test coupons was statistically significant, while the increase in the other 316L test coupon was not.","PeriodicalId":434862,"journal":{"name":"Volume 4B: Materials and Fabrication","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126426928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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