bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wet Coated Thin Barrier Films to Prevent Hydrogen Embrittlement on SUS304 Stainless Steel
Authors: Kawami Kazuyoshi , An Bai , Iijima Takashi , Fukuyama Seiji , Imaoka Mutsuharu , Tamai Hiroyasu , Tamura Motonori , Kinoshita Atsushi , Tanaka Toshiyuki 
Published: November 2019

Abstract
Hydrogen barrier coating is a promising technology for preventing hydrogen embrittlement in metals. In this study, characterizations of hydrogen barrier films coated on surfaces of austenitic stainless steel, SUS304 of the Japanese Industrial Standard (JIS), by wet coating processes applied electro-polishing and chemical oxidation method are carried out using cross-sectional transmission electron microscopy (TEM) analyses, and then slow strain rate tensile (SSRT) tests are performed in 1.1MPa hydrogen and nitrogen gases at room temperature. The hydrogen barrier films show 200–300nm total thickness of compositionally modulated Chromium oxide dense layer. The SSRT results reveal that both the elongation and reduction of area are decreased in hydrogen gas compared with those in nitrogen gas for the non barrier-coated specimens but no significant differences appear for the barrier-coated specimens. The fracture surface of the non barrier-coated specimen shows quasi-cleavagy cracking in hydrogen gas while that of the barrier-coated specimen shows only ductile dimple fracture in hydrogen gas, indicating that the coated films effectively prevent the hydrogen embrittlement of SUS304 stainless steel in hydrogen.
Study on Effects of Non-Isothermal Condition and Strain Holding on Environmentally Assisted Fatigue in PWR Primary Water Environment (Step III)
Authors: Takagoshi Daiki , Asada Seiji , Nomura Yuichirou , Stevens Gary , Ahluwalia Kawaljit 
Published: November 2019

Abstract
To further understand the environmentally assisted fatigue (EAF) behavior of Type 316 austenitic stainless steels (SS) in a pressurized water reactor (PWR) primary water environment, the influence of non-isothermal transient conditions was investigated using hollow, small-scale fatigue specimens. In our previous study (Step I: PVP2016-63798), isothermal and non-isothermal EAF tests were performed. The non-isothermal transient conditions for the fatigue tests investigated transients that consisted of both in-phase and out-of-phase temperature and strain variations. The result of this test series showed longer fatigue lives than those predicted using the modified rate approach and the EAF multiplier (Fen) presented in the draft of NUREG/CR-6909, Revision 1.
In our follow-on study (Step II: PVP2017-66233), one extra non-isothermal test was performed and application of the Weighted Stress Intensity Factor (K) Rate (WKR) method was discussed.
In the latest Step III testing, an extra non-isothermal test with periodic beachmarking has been performed. This paper discusses, based on the completion of all EAF tests performed in Steps I – III of this project, the effects of non-isothermal conditions and recommendations which are made for treatment of non-isothermal conditions in EAF assessments.
Development of New Design Fatigue Curves in Japan: Discussion of Fatigue Crack Growth Based on Fatigue Test Data With Large Scale Piping
Authors: Bodai Masaru , Fukuta Yuichi , Asada Seiji , Hayashi Kentaro 
Published: November 2019

Abstract
In order to develop new design fatigue curves for carbon steels & low alloy steels and austenitic stainless steels and a new design fatigue evaluation method that are rational and have clear design basis, Design Fatigue Curve (DFC) Phase 1 subcommittee and Phase 2 subcommittee were established in the Atomic Energy Research Committee in the Japan Welding Engineering Society. The study on design fatigue curves was actively performed in the subcommittees.
In the subcommittees, domestic and foreign fatigue data of small test specimens in air were collected and a comprehensive fatigue database was constructed. Using this fatigue database, the accurate best-fit curves of carbon steels & low alloy steels and austenitic stainless steels were developed by applying tensile strength to a parameter of the curve.
Regarding design factors on design fatigue curves, data scatter, mean stress correction, surface finishing effect, size effect and variable loading effect were investigated and each design factor was decided to be individually considered on the design fatigue curves.
A Japanese utility project performed large scale fatigue tests using austenitic stainless steel piping and low-alloy-steel flat plates as well as fatigue tests using small specimens to obtain not only basic data but also fatigue data of mean stress effect and surface finishing effect. Those test results were provided to the subcommittee and utilized the above studies.
In the last PVP Conference, the large scale fatigue tests using austenitic stainless steel piping were discussed for the best-fit curve of austenitic stainless steel (PVP2018-84436).
In this paper, further studies are performed based on fatigue crack growth of the large scale fatigue tests using austenitic stainless steel piping. From the obtained crack growth data of the tested piping, the number of cycles at 3-mm-deep crack depth and through-wall crack of piping compares with the best-fit curve developed by the DFC1 subcommittee with considering the confidence lower bounds to survey the fatigue life of piping, and size effect for fatigue lives is discussed. The relations between the fatigue crack growths and the number of cycles and the aspect ratios are surveyed including mean stress effect.
Particular Fatigue Resistance of Stabilized Stainless Steel: Endurance Limit, Strength and Ductility of Fatigued Steel
Authors: Solin Jussi , Alhainen Jouni , Arilahti Esko , Seppänen Tommi , Mayinger Wolfgang 
Published: November 2019

Abstract
Comprehensive experimental research on fatigue performance of niobium stabilized (type 347) X6CrNiNb1810mod steel has revealed particular features of cyclic performance. This paper reports and discusses on the endurance limit behavior studied by strain controlled HCF tests at room and elevated temperatures. In contrast to carbon steels, stainless steels can tolerate notable amounts of plastic strain and display broad hysteresis loops at and below endurance limit. Together with pronounced secondary hardening, this results to abrupt endurance limit behavior. The modified Miner rule with S-N–curves extrapolated to low amplitudes is generally applicable for carbon steels, but not for stainless. Effectiveness of the endurance limit even with variable amplitude straining was shown for 347 type steel. Extrapolation of ε-N curves beyond a few million cycles is conservative. An increase of temperature decreases, but does not vanish the endurance limit.
Another peculiar feature of the studied stainless steel is its superior ductility, which is not affected by partial fatigue ‘damage’. Five LCF tests at 325°C and 0.22 ≤ εa ≤ 0.5% were interrupted beyond the half-life condition (N/N25 ≥ 0.5) at 0.5 ≤ CUF ≤ 0.9. Cyclic straining was directly followed by monotonic pulling to fracture. Surprisingly low correlation between tensile properties and fatigue usage was observed. The ultimate tensile strength was preserved within 10 MPa (2.5%) in all cases. Yield strength and elongation remained practically unchanged by pre-fatigue.
This paper provides new experimental results. They are discussed together with earlier observations on the same steel extracted from a pipe, which has been manufactured for use in primary loop of a German NPP.
Real-Time Eddy Current Imaging and Flaw Detection Under Tube Support Plate by Cylinder-Type Magnetic Camera
Authors: Kim Sejin , Lee Hoyong , Lee Jinyi 
Published: November 2019

Abstract
In this study, a novel method is proposed to detect flaws directly under tube support plate (TSP) of heat exchanger tube using a cylinder-type magnetic camera (CMC). The CMC measures and images magnetic flux density changes occurring around a defect by applying a time-varying magnetic field to a metallic object through magnetic sensors which are arrayed in a matrix. If there is a flaw directly under the TSP, the magnetic flux density is concentrated in the TSP due to its higher permeability. Accordingly, flaws directly under the TSP are difficult to be detected. In order to solve this problem, the principle that the magnetic flux density distribution around the TSP is uniform in the circumferential direction is used. When the magnetic flux density signals obtained at the position where the TSP is placed are set as reference signals and the signals obtained by rotating the sensor probe in the circumferential direction are compared with the reference signals, it is possible to detect the flaw signals from which the TSP signals are removed. If the flaw is formed in the circumferential direction, the flaw can be detected by moving the sensor probe in the axial direction and comparing the signals with the reference signals. The proposed method to detect flaws directly under the TSP was verified using an artificially flawed heat exchanger tube (HXT) test specimen made of titanium alloy.
Retrofitting Non-Ductile RC Frames for Seismic Resistance Using Post-Installed Shear Walls
Authors: Chiu Chien-Kuo , Hsiao Fu-Pei , Liao Wen-I , Quacoo Samuel Jonathan , Ho Chin-En , Gu Zi-En 
Published: November 2019

Abstract
Reinforced Concrete (RC) frame structures that were designed and built according to older standards can be damaged during destructive earthquakes as a result of insufficient lateral strength and/or deformation capacity. Such structures must be retrofitted to satisfy the current requirements and to survive future earthquakes. Owing to its high lateral strength and stiffness capacity of an RC wall, the post-installation of an RC wall in a non-ductile frame for retrofit is a widely used retrofitting technique. However, for frame structures with low-strength concrete, the typically used connected construction method on the interface between existing and new concrete may be not able to provide effective force transfer, and may cause unexpected brittle failure in the retrofitted structure. Such unexpected brittle failure may reduce the seismic capacity of the structure and threaten its safety. Therefore, in this experimental investigation, two retrofitting methods that use a post-installed RC wall are proposed to improve the load transfer mechanism on the interface. The first involves a wall with diagonal rebar and boundary spirals, and the second involves a wall with an additional inner frame. A typical traditional retrofitting specimen was constructed and tested for comparison. Reversed cyclic loading is used to test the seismic capacity of the specimens. Finally, post-embedded piezoceramic-based sensors were used to monitor the structural health and detect damage in one of specimens during the test. The experimental results demonstrate the effectiveness of the piezoceramic-based approach to structural health monitoring and the ability of the method to detect damage in shear governed RC structures under seismic loading.
Testing of a Non-Cylindrical Vacuum Vessel
Authors: Reich Alton , Chew Geoffrey , May Douglas 
Published: November 2019

Abstract
Most vacuum vessels are bodies of revolution that are cylindrical or spherical. A square vacuum vessel was developed for a specialized application that needed to be suitable for repeated, rapid sealing and unsealing, and operation at mild vacuum (∼0.5 bara). This paper discusses the challenges that we faced in fabrication and testing of the vacuum vessel. The vacuum vessel was initially tested in a test rig. A second set of challenges was encountered when the vessel was tested mounted in the system. It captures the lessons learned from fabrication, rework, and modifications that were necessary to get the vessel to pass leakage testing.
ASME XI–RSE-M: General Comparison of Flaw Evaluation Rules
Authors: Faidy Claude 
Published: November 2019

Abstract
After a short review of the 2 Codes in term of flaw evaluation, this paper will compare Scope, Standards, Methods, Material Properties, Structural Factors of 2 major International In-service Codes: ASME Boiler and Pressure Vessel Codes – Section XI – “Rules for In-service Inspection of Nuclear Facility Components”, 2017 Edition and RSE-M “In-Service Inspection Rules for Mechanical Components of PWR Nuclear Island”, 2017 Edition.
The cracked components are evaluated by dedicated engineering methods: comparison of fracture mechanic parameters (K/ Kcp, J, C*...) with material properties (toughness KIC, JIC, J resistance curve...) associated to structural factors for margins evaluation.
The comparison will consider mainly Appendices A, C of ASME Section XI and Appendix 5 of RSE-M (Appendices 5.0 to 5.8).
To conclude, the paper will discuss gaps, needs, ongoing and future developments of both Codes, like Warm-pre stressing, Master Curve, Leak Before Break....
Seismic Evaluation Methods for Fire Protection Sprinkler Piping Systems in Buildings
Authors: Lin Fan-Ru , Chai Juin-Fu , Tsai Yung-An , Yeh Chang-Chen , Chang Kuo-Chun 
Published: November 2019

Abstract
Based on recent earthquakes experiences in Taiwan, losses do not necessarily result from damages of building structures but non-structural components. For instance, the leakage of the fire protection sprinkler systems in hospitals during small earthquakes could results in shortage of medical function and fire protection, and malfunction and repairs of medical equipment. The break of sprinkler systems caused by strong earthquakes could even harm the life safety. Taking a medium-scale hospital as an example, this research aims to conduct a simplified seismic evaluation method to improve seismic performance of the fire protection sprinkler system in critical buildings. The content of this research is summarized below:
1. Numerical analysis of the sample sprinkler piping system: a detailed numerical model of the fire protection sprinkler system in the sample hospital was established with SAP2000 v.20 software. Proper parameters to simulate the threaded joint of piping and the gap between adjacent partition walls or ceiling systems were proposed and verified by the results of component tests and shaking table tests. Ambient vibration tests in the sample hospital were conducted with velocimeters to clarify the structural characteristics of the building structure and the sprinkler piping system.
2. Fragility analysis of sprinkler piping systems: seismic fragility curves the fire protection sprinkler system in the sample hospital were conducted according to a mount of detailed analysis results and verified by the real damage state under Jiaxian earthquake. The effects of engineering demand parameters and categories of ground motion on fragility results are discussed for three types of failure modes.
3. Simplified seismic evaluation method for sprinkler piping systems: according to the results of shaking table tests and detailed analysis, a reliable simplified evaluation method was established to predict seismic behavior of typical sprinkler piping systems in hospitals by the information obtained from in-situ survey. The conservative level and accuracy of simplified evaluation results were verified by comparing the results of fragility analysis of numerical model and simplified evaluation.
Temperature Dependence of Fatigue Crack Growth in Low-Carbon Steel Under Gaseous Hydrogen
Authors: Takakuwa Osamu , Ogawa Yuhei , Okazaki Saburo , Matsunaga Hisao , Matsuoka Saburo 
Published: November 2019

Abstract
In order to elucidate the temperature dependence of hydrogen-assisted fatigue crack growth (HAFCG), the fatigue crack growth (FCG) test was performed on low-carbon steel JIS-SM490B according to ASTM E647 using compact tension (CT) specimen under 0.7 MPa (≈ 0.1 ksi) hydrogen-gas at room temperature (RT: 298 K (≈ 77 °F)) and 423 K (≈ 302 °F) at stress intensity factor range of ΔK = 30 MPa m1/2 (≈ 27 ksi in1/2). Electron backscatter diffraction (EBSD) observation was performed on the mid-thick section of CT specimen in order to investigate change in plasticity around the crack wake in gaseous hydrogen environment and how it changes due to temperature elevation. The obtained results showed the higher temperature, the lower intense of HAFCG as reported in our previous article. Plasticity around the crack wake became less in gaseous hydrogen environment, especially tested at 298 K. The propensity of the results obtained at higher temperature (423 K) can be separated into two cases: (i) intense plasticity occurs like tested in air, (ii) crack propagates straighter accompanying less plasticity like tested in gaseous hydrogen environment at 298 K. This implies macroscopic FCG rate is determined by combination of microscopic FCG rate in the case (i) and case (ii).
Basic Design Rules for Lines in Pulsating Flow Service
Authors: Eijgenhuijsen Menno , Masand Girish 
Published: November 2019

Abstract
To avoid unacceptable vibration of suction and discharge piping for reciprocating pumps and compressors, acoustic and mechanical response analyses are to be carried out. These analyses are generally provided by the suppliers of such equipment. This paper explains the fundamentals behind an acoustic and mechanical response analysis and provides a simple set of consolidated design and engineering rules. The paper encourages application of these rules while developing the equipment and piping layout as well as pipe support configuration. The aim of these rules is to minimize the chance for the ultimate supplier’s detailed acoustic & mechanical response analysis to recommend significant changes to the design in a late stage of a project. Specific emphasis is placed on how the support stiffness affects the natural frequency of the piping system and a practical methodology is provided to account for this in pipe support span calculations. This paper also describes the process information that needs to be submitted to the supplier to conduct a meaningful acoustic as well as mechanical response analysis. Acknowledging requirements for lines in pulsating service at a late stage in the project, not providing the supplier with the required process information or a piping and support configuration that is not ‘mature’ enough will most likely result in significant delay and cost.
Vibration Assessment of Thermowells
Authors: Prasad Piyush , Poddar Sudhanshu , Casey Finlay 
Published: November 2019

Abstract
ASME PTC 19.3 2016 code does not provide clear guideline on how to deal with the vibration problems of existing thermowells that are currently in operation and may be operating near inline or transverse vibration zone.
While the code allows passing through the in-line vibration zone, it prohibits operation completely in transverse vibration due to lock-in phenomenon. Once lock-in occurs, the thermowell gets into resonance and in the absence of adequate damping in the system, the thermowell vibration amplitude would keep on building with every cycle till eventual failure. It was identified that several operating assets had thermowells operating in the prohibited zone as per ASME PTC 19.3 and were facing a greater process safety risk.
Damping though difficult to predict, plays very crucial role in amplitude when thermowell is operated in critical zone i.e. within 20% of natural frequency. Hence it is very important to estimate the damping factor. ASME PTC 19.3 2016 have suggested conservative damping factor (ζ) of 0.0005 based on the lab studies. The test set-up assumes the piping system as rigid component, whereas, in the field piping systems are flexible. Using a conservative damping in the stress calculations leads to a high fictitious stress indicating failure of the thermowell.
In the present paper, a method is suggested to quantify the damping in the system by utilizing actual site vibration measurement of thermowell in the finite element analysis and thus a more realistic assessment of the stresses in the thermowell can be made. This assessment presented a much larger damping present in the system than ASME suggested and led asset to continue operate the plant with no risk of unplanned downtime as well as technical integrity of equipment. The results are presented for one sample thermowells.
Various Strength Properties of Aluminum Alloys in High-Pressure Hydrogen Gas Environment
Authors: Matsuoka Saburo , Iijima Takashi , Yoshida Satoko , Yamabe Junichiro , Matsunaga Hisao 
Published: November 2019

Abstract
Three types of strength tests, slow strain rate tensile (SSRT), fatigue life, and fatigue crack growth (FCG) tests, were performed using six types of aluminum alloys, 5083-O, 6061-T6, 6066-T6, 7N01-T5, 7N01-T6, and 7075-T6, in air and 115 MPa hydrogen gas at room temperature. All the strength properties of every material were not deteriorated in 115 MPa hydrogen gas. In all the materials, FCG rates were lower in 115 MPa hydrogen gas than in air. This was considered to be due to a lack of water- or oxygen-adsorbed film at crack tip in hydrogen gas. In 5083-O, 6061-T6 and 6066-T6, relative reduction in area (RRA) were remarkably higher in 115 MPa hydrogen gas than in air. These differences were attributed to a hydrostatic pressure produced in 115 MPa hydrogen gas. In contrast, in 7N01-T5, 7N01-T6 and 7075-T6, the values of RRA in 115 MPa hydrogen gas were nearly the same as those in air. Observation of fractured specimens inferred that the degree of such a hydrogen-induced improvement was determined by the fracture mode (e.g. cup-and-cone or shear fracture), which is dominated by the microstructure morphology.
The Fundamental Mechanical Characteristics Evaluation for Bolted Pipe Flange Connections With RTJ Gaskets Under Internal Pressure
Authors: Nakade Kenshiro , Sato Koji , Sawa Toshiyuki 
Published: November 2019

Abstract
Bolted pipe flange connections with metallic flat gaskets or ring type joint (RTJ) gaskets are used under higher pressure and higher temperature. However, a sealing mechanism is not known and a design method is not established how to determine bolt preload for preventing leakage from the connection with metallic gaskets. In addition, the characteristics of the connection are not known when oval and octagonal gaskets are used. In previous paper, when the contact stress of metallic flat gasket reaches the stress at plastic deformation inflection point, the leak rate is decreased rapidly. However, the leak rate could be measured up to 1.0 × 10−5 Pa · m3/s level. The objectives of the paper are to measure the leak rate of the metallic flat gasket of which the contact stress is over the stress at plastic deformation inflection point, and to measure the leak rate of 1.0 × 10−9∼10 Pa · m3/s level in the flat metallic gasket in the platen tests and the connection with RTJ gaskets. In addition, the characteristics of the connection are examined when oval and octagonal gaskets are used. As a result, it is found that the leak rate for the metallic flat gasket can be measured around 1.0 × 10−9∼10 Pa · m3/s in the platen tests when the contact stress of aluminum gasket reaches the stress at plastic deformation inflection point and more while the leak rate of SUS 304 flat gasket is around 1.0 × 10−7∼8 Pa · m3/s even if the contact stress is over 1.3 times of the stress at plastic deformation inflection point. In addition, the sealing characteristics of the connection with oval gasket are shown to be better than that with octagonal gasket. From a laser microscope observation, it is found that the contact area of oval gasket in the connection is smaller than that of octagonal gasket in the connection.