Making light water reactor (LWR) components using additive manufacturing (AM) provides a high degree of design freedom to create complex near net shape geometries, with significant reduction in the deployment time. Since most of the current AM research focus on the refining of the fabrication variables, little information exists on the actual corrosion behavior (including general corrosion, localized corrosion and environmentally assisted cracking - EAC) of AM components. The most frequent operational material failure modes in LWR is EAC and debris fretting of fuel rods, therefore the objective of this work was to evaluate the environmental performance of AM type 316L SS in relation to the traditionally melted and forged wrought material. Stress corrosion cracking results show similar behavior between AM and wrought 316L SS in high temperature water. Ambient temperature electrochemical testing showed that the AM 316L SS was slightly more resistant to localized corrosion than the traditional wrought material and that AM material did not suffer sensitization during fabrication or heat treatment processes.
{"title":"Using Additive Manufacturing for Making Light Water Reactor Components","authors":"R. Rebak, X. Lou","doi":"10.1115/pvp2019-93129","DOIUrl":"https://doi.org/10.1115/pvp2019-93129","url":null,"abstract":"\u0000 Making light water reactor (LWR) components using additive manufacturing (AM) provides a high degree of design freedom to create complex near net shape geometries, with significant reduction in the deployment time. Since most of the current AM research focus on the refining of the fabrication variables, little information exists on the actual corrosion behavior (including general corrosion, localized corrosion and environmentally assisted cracking - EAC) of AM components. The most frequent operational material failure modes in LWR is EAC and debris fretting of fuel rods, therefore the objective of this work was to evaluate the environmental performance of AM type 316L SS in relation to the traditionally melted and forged wrought material. Stress corrosion cracking results show similar behavior between AM and wrought 316L SS in high temperature water. Ambient temperature electrochemical testing showed that the AM 316L SS was slightly more resistant to localized corrosion than the traditional wrought material and that AM material did not suffer sensitization during fabrication or heat treatment processes.","PeriodicalId":23651,"journal":{"name":"Volume 6B: Materials and Fabrication","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75483379","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}
This work presents an investigation of the ductile tearing properties for a girth weld made of an ASTM A106 Gr C steel using the SMAW welding process with a low hydrogen E7018 electrode thereby resulting in a weld with high strength overmatching with respect to the base material. Testing of the pipe girth welds employed side-grooved, clamped SE(T) specimens with a weld centerline notch to determine the crack growth resistance curves based upon the unloading compliance (UC) method using a single specimen technique. Recently developed compliance functions and η-factors applicable to weld centerline notched SE(T) specimens are introduced to determine crack growth resistance data from laboratory measurements of load-displacement records. While the UC procedure resulted in measured crack extensions for the tested specimens with weld centerline notch that underestimated the 9-point average crack extension, our preliminary results demonstrate the capability of the methodology in describing crack growth resistance behavior which serves as a basis for ductile tearing assessments in ECA procedures applicable to overmatched girth welds and similar structural components.
本文研究了采用低氢E7018焊条进行SMAW焊接的ASTM A106 Gr C钢环焊缝的韧性撕裂性能，从而获得了与基材相匹配的高强度焊缝。采用带焊缝中心线缺口的侧槽夹紧SE(T)试样对管道环焊缝进行测试，采用单试样技术基于卸载依从性(UC)方法确定裂纹扩展阻力曲线。引入了最近开发的适用于焊缝中心线缺口SE(T)试样的柔度函数和η因子，以确定实验室测量的载荷-位移记录的裂纹扩展阻力数据。虽然UC程序导致了带有焊缝中心线缺口的测试样品的裂纹扩展测量，低估了9点的平均裂纹扩展，但我们的初步结果证明了该方法在描述裂纹扩展阻力行为方面的能力，该方法可作为适用于超匹配环焊缝和类似结构部件的ECA程序中韧性撕裂评估的基础。
{"title":"Fracture Toughness Testing of an Overmatched Pipe Girth Weld Using Clamped SE(T) Specimens","authors":"C. Ferreira, D. Burgos, C. Ruggieri","doi":"10.1115/pvp2019-93256","DOIUrl":"https://doi.org/10.1115/pvp2019-93256","url":null,"abstract":"\u0000 This work presents an investigation of the ductile tearing properties for a girth weld made of an ASTM A106 Gr C steel using the SMAW welding process with a low hydrogen E7018 electrode thereby resulting in a weld with high strength overmatching with respect to the base material. Testing of the pipe girth welds employed side-grooved, clamped SE(T) specimens with a weld centerline notch to determine the crack growth resistance curves based upon the unloading compliance (UC) method using a single specimen technique. Recently developed compliance functions and η-factors applicable to weld centerline notched SE(T) specimens are introduced to determine crack growth resistance data from laboratory measurements of load-displacement records. While the UC procedure resulted in measured crack extensions for the tested specimens with weld centerline notch that underestimated the 9-point average crack extension, our preliminary results demonstrate the capability of the methodology in describing crack growth resistance behavior which serves as a basis for ductile tearing assessments in ECA procedures applicable to overmatched girth welds and similar structural components.","PeriodicalId":23651,"journal":{"name":"Volume 6B: Materials and Fabrication","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75810415","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 NeT-TG6 project examines the behaviour of a three-pass slot-welded benchmark made from Alloy 600 base material and Alloy 82 weld metal. This paper reports the material characterization studies conducted as part of the extensive round-robin activities performed to characterise the residual stress state in the TG6 benchmark using both measurement and simulation. An additional three slot specimen with one, two and three pass welds was manufactured to allow extensive characterization studies and comparison with the actual NeT-TG6 specimen, which contains only a single three-pass weld. Optical metallography and chemical composition studies examined the variability of the chemical composition and microstructure between parent material and weld metal with varying levels of dilution and differing thermo-mechanical behaviour. Micro indentation measurements were used to acquire hardness maps of the welded samples and reveal the impact of thermo-mechanical cyclic history. Electron microscopy and in particular electron back scattered diffraction (EBSD) was used to estimate the grain size variation, and, in the deformed parent and each weld bead, to assess the accumulation of plastic deformation.
{"title":"Material Characterization on the Nickel-Based Alloy 600/82 NeT-TG6 Benchmark Weldments","authors":"V. Akrivos, Michael C. Smith","doi":"10.1115/pvp2019-94017","DOIUrl":"https://doi.org/10.1115/pvp2019-94017","url":null,"abstract":"\u0000 The NeT-TG6 project examines the behaviour of a three-pass slot-welded benchmark made from Alloy 600 base material and Alloy 82 weld metal. This paper reports the material characterization studies conducted as part of the extensive round-robin activities performed to characterise the residual stress state in the TG6 benchmark using both measurement and simulation. An additional three slot specimen with one, two and three pass welds was manufactured to allow extensive characterization studies and comparison with the actual NeT-TG6 specimen, which contains only a single three-pass weld. Optical metallography and chemical composition studies examined the variability of the chemical composition and microstructure between parent material and weld metal with varying levels of dilution and differing thermo-mechanical behaviour. Micro indentation measurements were used to acquire hardness maps of the welded samples and reveal the impact of thermo-mechanical cyclic history. Electron microscopy and in particular electron back scattered diffraction (EBSD) was used to estimate the grain size variation, and, in the deformed parent and each weld bead, to assess the accumulation of plastic deformation.","PeriodicalId":23651,"journal":{"name":"Volume 6B: Materials and Fabrication","volume":"29 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84293256","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}
M. Asadi, M. Mohseni, M. Kashani, Michael Fernández, Mathew Smith
Distortion is a common problem in welded structures, and therefore welding standards require a mitigation plan to be in place before welding. When dealing with multiple welds, an optimal intermittent weld sequence can effectively minimize the distortion by counter-balancing the transient distortion during welding. However, the process of finding an effective weld sequence is a challenging task given a large number of possible combinations, i.e. several thousand for a few welds. As an acceptable approach, welding simulation tools allow engineers to optimize a welding sequence without the need for multiple physical samples. Despite efficient simulation tools and powerful supercomputers, yet simulation tools have been limited by CPU time and therefore not mature for practical designs. To this end, we constructed and integrated an inexpensive low-fidelity machine learning (ML) algorithm with the expensive high-fidelity simulation. This ML model was then trained to increase the fidelity by a wisely chosen train set of simulation to construct a meta-model for active exploration of various weld sequence scenarios. As opposed to existing ML algorithms that require an extensive data set to train, our algorithm picks relatively small training set to construct a meta-model. We present an example of our algorithm implemented in a real welded structure project.
{"title":"Welding Simulation Integrated With Machine Learning to Train a Meta-Model for Fast Exploration of Various Weld Sequence Scenarios","authors":"M. Asadi, M. Mohseni, M. Kashani, Michael Fernández, Mathew Smith","doi":"10.1115/pvp2019-93672","DOIUrl":"https://doi.org/10.1115/pvp2019-93672","url":null,"abstract":"\u0000 Distortion is a common problem in welded structures, and therefore welding standards require a mitigation plan to be in place before welding. When dealing with multiple welds, an optimal intermittent weld sequence can effectively minimize the distortion by counter-balancing the transient distortion during welding. However, the process of finding an effective weld sequence is a challenging task given a large number of possible combinations, i.e. several thousand for a few welds. As an acceptable approach, welding simulation tools allow engineers to optimize a welding sequence without the need for multiple physical samples. Despite efficient simulation tools and powerful supercomputers, yet simulation tools have been limited by CPU time and therefore not mature for practical designs. To this end, we constructed and integrated an inexpensive low-fidelity machine learning (ML) algorithm with the expensive high-fidelity simulation. This ML model was then trained to increase the fidelity by a wisely chosen train set of simulation to construct a meta-model for active exploration of various weld sequence scenarios. As opposed to existing ML algorithms that require an extensive data set to train, our algorithm picks relatively small training set to construct a meta-model. We present an example of our algorithm implemented in a real welded structure project.","PeriodicalId":23651,"journal":{"name":"Volume 6B: Materials and Fabrication","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91239399","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}
In order to standardize the simple testing method to evaluate mechanical properties using hollow-type specimen in the high pressure hydrogen gas, influences of the hole and inner surface roughness on the relative reduction of area (RRA) and other properties in slow strain rate tensile (SSRT) tests were investigated on different surface finished specimens at 105 MPa hydrogen gas for SUS316L and JIS SNCM439 steels. There is no influence of the hole and the inner pressure for the yield strength and the tensile strength. The RRA slightly increased in less roughness specimens. So, the axially polished finish for the hollow specimen will be proposed to the standard testing procedures of the SSRT test with this method to evaluate mechanical properties in the high pressure hydrogen gas.
{"title":"Influence of Roughness of Inner Surface of Simple Mechanical Testing Method to Evaluate Influence of High Pressure Hydrogen Gas","authors":"T. Ogata, Y. Ono","doi":"10.1115/pvp2019-93492","DOIUrl":"https://doi.org/10.1115/pvp2019-93492","url":null,"abstract":"\u0000 In order to standardize the simple testing method to evaluate mechanical properties using hollow-type specimen in the high pressure hydrogen gas, influences of the hole and inner surface roughness on the relative reduction of area (RRA) and other properties in slow strain rate tensile (SSRT) tests were investigated on different surface finished specimens at 105 MPa hydrogen gas for SUS316L and JIS SNCM439 steels.\u0000 There is no influence of the hole and the inner pressure for the yield strength and the tensile strength. The RRA slightly increased in less roughness specimens. So, the axially polished finish for the hollow specimen will be proposed to the standard testing procedures of the SSRT test with this method to evaluate mechanical properties in the high pressure hydrogen gas.","PeriodicalId":23651,"journal":{"name":"Volume 6B: Materials and Fabrication","volume":"136 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86414793","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}
Jae-Yoon Jeong, M. Lee, Yun‐Jae Kim, R. Sindelar, A. Duncan
This paper presents a new test method for assessing chloride induced stress corrosion cracking occurred in metal canisters used for storing spent nuclear fuels. The material applied to experiment is austenitic stainless steel, SS304 similarly used on manufacturing canisters and the experiment is carried out with immersing a compact tension specimen to chloride solution made up with artificial sea salt. Constant displacement condition using bolt tightening is applied to the test and a load is measured as a function of time using a load cell. Five specimens are used for the experiment at temperature of 50 °C for several months and stress intensity factor is calculated through the measured relaxed load and crack length on fractured surface of the specimen. Crack growth rate is presented in terms of test periods and consequently this apparatus suggests a method for evaluating structural integrity of chloride stress corrosion cracking.
{"title":"Development of an Apparatus for Chloride Induced Stress Corrosion Cracking Test Using Immersion Method With Constant Displacement Condition","authors":"Jae-Yoon Jeong, M. Lee, Yun‐Jae Kim, R. Sindelar, A. Duncan","doi":"10.1115/pvp2019-93922","DOIUrl":"https://doi.org/10.1115/pvp2019-93922","url":null,"abstract":"\u0000 This paper presents a new test method for assessing chloride induced stress corrosion cracking occurred in metal canisters used for storing spent nuclear fuels. The material applied to experiment is austenitic stainless steel, SS304 similarly used on manufacturing canisters and the experiment is carried out with immersing a compact tension specimen to chloride solution made up with artificial sea salt. Constant displacement condition using bolt tightening is applied to the test and a load is measured as a function of time using a load cell. Five specimens are used for the experiment at temperature of 50 °C for several months and stress intensity factor is calculated through the measured relaxed load and crack length on fractured surface of the specimen. Crack growth rate is presented in terms of test periods and consequently this apparatus suggests a method for evaluating structural integrity of chloride stress corrosion cracking.","PeriodicalId":23651,"journal":{"name":"Volume 6B: Materials and Fabrication","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80619549","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}
K. Wada, J. Yamabe, Yuhei Ogawa, O. Takakuwa, T. Iijima, H. Matsunaga
The effect of hydrogen on the deformation and fracture behavior in pure Cu, pure Ni and Cu–Ni alloy was studied via tensile tests of H-charged, smooth and circumferentially-notched specimens at room temperature (RT) and 77 K. Hydrogen-diffusion properties were determined by the desorption method. To obtain a uniform hydrogen concentration in the H-charged specimens, specimens were exposed to 100-MPa hydrogen gas at 543 K for 200 h, based on the determined hydrogen diffusivity. In tensile tests of smooth pure Ni and Cu–Ni alloy specimens at RT, common hydrogen effects were detected, namely, an increase in yield and flow stresses — a hardening effect; and a ductility loss that was accompanied by a change in fracture surface from ductile to brittle feature — an embrittling effect. With regard to the embrittling effect, the pure Ni and Cu–Ni alloy showed different fracture-surface morphologies at RT; the pure Ni showed an intergranular (IG) surface and the Cu–Ni alloy surface was flat. However, a number of IG cracks were detected beneath the fracture surfaces on the smooth Cu-Ni alloy. The tensile tests of the H-charged smooth specimens at 77 K yielded an IG surface for the pure Ni and a ductile fracture surface with dimples in the Cu–Ni alloy. In contrast, tensile tests of the H-charged, notched specimens at RT demonstrated clear IG fractures for the pure Ni and Cu–Ni alloy. These facts indicate that IG cracking was the first step in the embrittling process for the pure Ni and Cu–Ni alloy, and IG cracking was accompanied by a large plastic deformation that formed the flat surface (unclear IG surface) for the smooth Cu–Ni alloy. Considering that the HE of both pure Ni and Cu–Ni alloy was related to IG cracking, possible mechanisms were discussed and tensile tests performed at 77 K suggested two possibilities: (I) interaction between hydrogen-moving dislocation is more important in the HE process of the Cu-Ni alloy compared to the pure Ni; (II) hydrogen transportation towards grain boundaries are required to cause the IG fracture in the Cu-Ni alloy.
{"title":"Fracture and Deformation Behavior in Slow-Strain-Rate Tensile Testing of Cu–Ni Alloy With Internal Hydrogen","authors":"K. Wada, J. Yamabe, Yuhei Ogawa, O. Takakuwa, T. Iijima, H. Matsunaga","doi":"10.1115/pvp2019-93477","DOIUrl":"https://doi.org/10.1115/pvp2019-93477","url":null,"abstract":"\u0000 The effect of hydrogen on the deformation and fracture behavior in pure Cu, pure Ni and Cu–Ni alloy was studied via tensile tests of H-charged, smooth and circumferentially-notched specimens at room temperature (RT) and 77 K. Hydrogen-diffusion properties were determined by the desorption method. To obtain a uniform hydrogen concentration in the H-charged specimens, specimens were exposed to 100-MPa hydrogen gas at 543 K for 200 h, based on the determined hydrogen diffusivity. In tensile tests of smooth pure Ni and Cu–Ni alloy specimens at RT, common hydrogen effects were detected, namely, an increase in yield and flow stresses — a hardening effect; and a ductility loss that was accompanied by a change in fracture surface from ductile to brittle feature — an embrittling effect. With regard to the embrittling effect, the pure Ni and Cu–Ni alloy showed different fracture-surface morphologies at RT; the pure Ni showed an intergranular (IG) surface and the Cu–Ni alloy surface was flat. However, a number of IG cracks were detected beneath the fracture surfaces on the smooth Cu-Ni alloy. The tensile tests of the H-charged smooth specimens at 77 K yielded an IG surface for the pure Ni and a ductile fracture surface with dimples in the Cu–Ni alloy. In contrast, tensile tests of the H-charged, notched specimens at RT demonstrated clear IG fractures for the pure Ni and Cu–Ni alloy. These facts indicate that IG cracking was the first step in the embrittling process for the pure Ni and Cu–Ni alloy, and IG cracking was accompanied by a large plastic deformation that formed the flat surface (unclear IG surface) for the smooth Cu–Ni alloy. Considering that the HE of both pure Ni and Cu–Ni alloy was related to IG cracking, possible mechanisms were discussed and tensile tests performed at 77 K suggested two possibilities: (I) interaction between hydrogen-moving dislocation is more important in the HE process of the Cu-Ni alloy compared to the pure Ni; (II) hydrogen transportation towards grain boundaries are required to cause the IG fracture in the Cu-Ni alloy.","PeriodicalId":23651,"journal":{"name":"Volume 6B: Materials and Fabrication","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84999447","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 Japanese welding guideline for duplex stainless steels (DSSs)1) has been developed in a Sub-Committee of Chemical Plant Welding Research Committee in the Japan Welding Engineering Society. The guideline recommends 13 key points as a basis to prevent the unforeseen corrosion of weldments, which are based on practical experience in Japanese Oil & Gas and Chemical industries and similar published guidelines. The principal concept is how to obtain an acceptable ratio of ferrite/austenite phase balance along with no detrimental intermetallic compounds in the weld metal and heat affected zone. For the weld metal, consumable selection, the shielding and purging gas composition and weld heat input control are most critical. For HAZ, the nitrogen content of the base metal is most critical. This guideline is developed for DSS welders and welding engineers so as to understand the difference of DSS from standard austenitic stainless steel. This guideline is composed of three parts, the first is 13 basic recommendations, the second is to explain some technical aspects for these 13 key points and the third contains comprehensive data relating DSS base metal and weld metal including some important key points for each step of fabrication to understand the welding characteristics of DSS clearly. This paper introduces the basic 13 recommendations for guidance purpose in addition to the mandatory requirements of the construction code in Japan.
{"title":"Japanese Welding Guideline for Duplex Stainless Steels","authors":"Iwamoto Hiroyuki, F. Minami","doi":"10.1115/pvp2019-93022","DOIUrl":"https://doi.org/10.1115/pvp2019-93022","url":null,"abstract":"\u0000 A Japanese welding guideline for duplex stainless steels (DSSs)1) has been developed in a Sub-Committee of Chemical Plant Welding Research Committee in the Japan Welding Engineering Society. The guideline recommends 13 key points as a basis to prevent the unforeseen corrosion of weldments, which are based on practical experience in Japanese Oil & Gas and Chemical industries and similar published guidelines. The principal concept is how to obtain an acceptable ratio of ferrite/austenite phase balance along with no detrimental intermetallic compounds in the weld metal and heat affected zone. For the weld metal, consumable selection, the shielding and purging gas composition and weld heat input control are most critical. For HAZ, the nitrogen content of the base metal is most critical. This guideline is developed for DSS welders and welding engineers so as to understand the difference of DSS from standard austenitic stainless steel. This guideline is composed of three parts, the first is 13 basic recommendations, the second is to explain some technical aspects for these 13 key points and the third contains comprehensive data relating DSS base metal and weld metal including some important key points for each step of fabrication to understand the welding characteristics of DSS clearly.\u0000 This paper introduces the basic 13 recommendations for guidance purpose in addition to the mandatory requirements of the construction code in Japan.","PeriodicalId":23651,"journal":{"name":"Volume 6B: Materials and Fabrication","volume":"43 1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87826351","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}
SSRT and fatigue life tests of SUS301 austenitic stainless steel were performed to examine the effect of hydrogen on the mechanical properties. Ni content of SUS301, 6.00–8.00 mass%, is lower than that of SUS304 in JIS standard for austenitic stainless steels. In the case of SSRT tests, specimens with and without hydrogen charging were tested in laboratory air at room temperature (R.T.), −45 °C, and −80 °C. The 0.2% offset yield strength (Ys) of the hydrogen charged specimens was less than 300 MPa in the tested temperature range. The tensile strength (Ts) and total elongation (El) of hydrogen charged specimens decreased remarkably. With decreasing testing temperature, fracture surface facet of the hydrogen charged specimens became dominant. Therefore, the effect of hydrogen on the tensile properties of SUS301 is supposed to be large. Specimens with and without hydrogen charging were fatigued in laboratory air at R.T., and specimens without hydrogen charging were fatigued in 100 MPa hydrogen gas atmosphere at R.T. Number of cycles (Nf) at finite fatigue life region of the hydrogen charged specimens and of the specimens tested in hydrogen gas were two orders shorter than that of the specimens tested in air. However, the finite fatigue life region of the hydrogen charged specimens and the specimens tested in hydrogen gas showed a different profile. Additionally, ferrite equivalents of all fatigue tested specimens and fatigued fracture surface morphology suggested the fatigue fracture mechanism between the hydrogen charged specimens tested in air and the non-charged specimens tested in 100 MPa hydrogen gas seems to be different. Therefore, further investigations are required to clear this difference.
{"title":"Effect of Hydrogen on Tensile and Fatigue Properties of SUS301 Austenitic Stainless Steel","authors":"T. Iijima, H. Enoki, J. Yamabe, M. Kimura, B. An","doi":"10.1115/pvp2019-93395","DOIUrl":"https://doi.org/10.1115/pvp2019-93395","url":null,"abstract":"\u0000 SSRT and fatigue life tests of SUS301 austenitic stainless steel were performed to examine the effect of hydrogen on the mechanical properties. Ni content of SUS301, 6.00–8.00 mass%, is lower than that of SUS304 in JIS standard for austenitic stainless steels. In the case of SSRT tests, specimens with and without hydrogen charging were tested in laboratory air at room temperature (R.T.), −45 °C, and −80 °C. The 0.2% offset yield strength (Ys) of the hydrogen charged specimens was less than 300 MPa in the tested temperature range. The tensile strength (Ts) and total elongation (El) of hydrogen charged specimens decreased remarkably. With decreasing testing temperature, fracture surface facet of the hydrogen charged specimens became dominant. Therefore, the effect of hydrogen on the tensile properties of SUS301 is supposed to be large. Specimens with and without hydrogen charging were fatigued in laboratory air at R.T., and specimens without hydrogen charging were fatigued in 100 MPa hydrogen gas atmosphere at R.T. Number of cycles (Nf) at finite fatigue life region of the hydrogen charged specimens and of the specimens tested in hydrogen gas were two orders shorter than that of the specimens tested in air. However, the finite fatigue life region of the hydrogen charged specimens and the specimens tested in hydrogen gas showed a different profile. Additionally, ferrite equivalents of all fatigue tested specimens and fatigued fracture surface morphology suggested the fatigue fracture mechanism between the hydrogen charged specimens tested in air and the non-charged specimens tested in 100 MPa hydrogen gas seems to be different. Therefore, further investigations are required to clear this difference.","PeriodicalId":23651,"journal":{"name":"Volume 6B: Materials and Fabrication","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75478255","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}
In this paper, three tenile strain capacity (TSC) prediction models developed for strain-based design (SBD) of girth-welded pipelines were reviewed, together with a brief introduction of technical backgrounds of their development. Most TSC models rely on small-scale mechanical and fracture toughness measurements to estimate the TSC of pipelines. Hence, we surveyed published experimental and computational data to examine the transferability of small-scale fracture toughness measurements to large-scale pipe fractures. Lastly, some gaps and issues that were found from the review are proposed for improvement of TSC models for SBD. The critical issues found with current TSC models and SBD are (a) differences in strain measurement for full-scale pipe tests/simulations, (b) multiple crack tip opening displacement (CTOD) definitions, (c) no application of J-integral as a toughness parameter, (d) no consensus on failure criteria, and (e) inconsideration of thermal and natural strain aging effects.
{"title":"Review of Tensile Strain Capacity Prediction Models for Strain-Based Design of Pipelines","authors":"D. Park, J. Gianetto","doi":"10.1115/pvp2019-93220","DOIUrl":"https://doi.org/10.1115/pvp2019-93220","url":null,"abstract":"\u0000 In this paper, three tenile strain capacity (TSC) prediction models developed for strain-based design (SBD) of girth-welded pipelines were reviewed, together with a brief introduction of technical backgrounds of their development. Most TSC models rely on small-scale mechanical and fracture toughness measurements to estimate the TSC of pipelines. Hence, we surveyed published experimental and computational data to examine the transferability of small-scale fracture toughness measurements to large-scale pipe fractures. Lastly, some gaps and issues that were found from the review are proposed for improvement of TSC models for SBD. The critical issues found with current TSC models and SBD are (a) differences in strain measurement for full-scale pipe tests/simulations, (b) multiple crack tip opening displacement (CTOD) definitions, (c) no application of J-integral as a toughness parameter, (d) no consensus on failure criteria, and (e) inconsideration of thermal and natural strain aging effects.","PeriodicalId":23651,"journal":{"name":"Volume 6B: Materials and Fabrication","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76944469","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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