Volume 6: Materials and Fabrication最新文献

{"title":"Probabilistic Creep Modeling of 304 Stainless Steel Using a Modified Wilshire Creep-Damage Model","authors":"Md. Abir Hossain, J. Cano, C. Stewart","doi":"10.1115/pvp2020-21613","DOIUrl":"https://doi.org/10.1115/pvp2020-21613","url":null,"abstract":"\u0000 Pressure vessel components subject to high temperature and pressure are susceptible to life-limiting creep and/or creep-induced failure. Traditional continuum damage mechanics (CDM) based creep-damage model are used extensively for the prediction and design against creep in these components. Conventional creep experiments show considerable uncertainty in the creep response of materials where scatter can span decades of creep life. The objective of this paper is to introduce the probabilistic methods into a deterministic creep-damage model in order to predict experimental uncertainty. In this study, a modified Wilshire model capable of creep deformation, damage, and rupture prediction is selected. Creep deformation data for 304 stainless steel is collected from the literature consisting of quintuplicate (five) tests at 600°C with varying stress levels. It is hypothesized that the scatter in creep data is due to: test condition (temperature fluctuations and eccentric loading), initial damage (pre-existing surface and sub-surface defects), and metallurgical (local variation in microstructure) uncertainties. Probability distribution functions (pdfs) and Monte Carlo simulations are applied to introduce the uncertainties into the modified Wilshire equations. The domain of each source of uncertainty must be defined. A systematic calibration approach is followed where the material constant for each creep curve (in the quintuple) are obtained and statistical analysis is performed on the material properties to assess the random distribution associated with each uncertain material parameter. The probabilistic calibration begins with the introduction of test condition randomness (±2°C and ±3.2% MPa of nominal temperature/stress) in accordance with the ASTM standards. Cross calibration of temperature-stress variability proceeds the approximation of initial damage uncertainty which captures the remaining scatter in the data. Deterministic calibration unveils the range of variabilities associated with the material properties. The best-fitted pdfs are assigned to each uncertain parameter and subsequently, the deterministic model is converted into a probabilistic model where reliability is a tunable factor. A large number of Monte Carlo simulation are conducted to generate probabilistic creep deformation, minimum-creep-strain-rate (MCSR), and stress-rupture (SR) predictions. It is demonstrated that the probabilistic model produces quantitatively and qualitatively good fits when compared with experimental data. Future work will be directed towards the inclusion of service condition related uncertainty (power plant, turbine blade, Gen IV nuclear reactor application) into the probabilistic framework where the uncertainties are more robust.","PeriodicalId":396247,"journal":{"name":"Volume 6: Materials and Fabrication","volume":"70 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124841446","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}

{"title":"Increasing Fatigue Strength and Wear Resistance of Additive Manufactured Nickel Alloy (UNS N07718) by Ultrasonic Nanocrystal Surface Modification (UNSM) Treatment","authors":"Y. Pyun, Seimi Choi, Ruslan M. Karimbaev, J. Ro, Choong Ho Sanseong, Jan Sembiring, Jong Seog Kim, A. Amanov, S. Kang, H. Ahn","doi":"10.1115/pvp2020-21350","DOIUrl":"https://doi.org/10.1115/pvp2020-21350","url":null,"abstract":"\u0000 Additive Manufacturing (AM) which is also known as metal 3D printing technique is a promising process with a massive potential for developing a component for wide range applications for various industries. Recently, AM process was introduced to the nuclear power plant industry as AM is capable of manufacturing the substitution of aging and obsolete component. However, the AM component has inferior mechanical properties and performance in terms of fatigue strength and wear resistance compared to its conventionally manufactured counterpart. Ultrasonic Nanocrystal Surface Modification (UNSM) is one of mechanical surface modification treatment known for improving fatigue strength and wear resistance of wrought material. Hence, in this study effect of UNSM treatment on fatigue strength and wear resistance of additive manufactured material was investigated. The investigation was done to Ni-based alloy 718 (UNS N07718) as this material is used for nuclear power plant components and was manufactured with two different AM techniques namely Powder Bed Fusion (PBF) and Direct Energy Deposition (DED) processes. The evaluation was conducted by comparing the as-polished and UNSM-treated specimens for each AM processes by performing fatigue and tribo tests. This result will become a part of the technical basis for KEPIC Code Case development.","PeriodicalId":396247,"journal":{"name":"Volume 6: Materials and Fabrication","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124399218","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}

{"title":"Comparative Stress Analyses of Dropped Spent Nuclear Fuel Assembly in a Prototypal Cask","authors":"SaeHanSol Kang, Dong-Hyun Kim, Yoon-Suk Chang, Sang Hwan Lee","doi":"10.1115/pvp2020-21510","DOIUrl":"https://doi.org/10.1115/pvp2020-21510","url":null,"abstract":"\u0000 While establishment of appropriate policies and securing key technologies on spent nuclear fuels are state-of-the-arts in the world due to saturation of fuel pools and/or temporary facilities, the details of transportation, storage and repository are different depending on the situation in each country. Thereby, accurate integrity assessment of specific transportation casks and contained fuel assemblies as well as their breakdown effects on the public and environment are becoming more important.\u0000 The purpose of this study is to carry out parametric stress analyses of spent nuclear fuel assembly in a prototypal dual purpose cask under development. As the representative postulated accident conditions, four scenarios were selected such as vertical, horizontal, corner and oblique drop from 9 m height on the ground. Then, taking into account computational cost, a simple model that considers only the equivalent mass of the fuel assembly was made for preliminary finite element analyses to determine the most dangerous drop condition and critical location. Subsequently, a detailed model that considers the acceleration of fuel assembly was made based on the preliminary analysis results and finite element analyses were carried out to calculate engineering parameters. Resulting membrane and bending stress intensities were compared with allowable design limits, of which findings will be used as technical background for development of transportation cask and management of the spent nuclear fuel integrity.","PeriodicalId":396247,"journal":{"name":"Volume 6: Materials and Fabrication","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127036662","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}

{"title":"Characterization of Anisotropic Mechanical Properties of X70 Spiral Welded Steel Pipes","authors":"D. Park, Jie Liang, J. Gravel","doi":"10.1115/pvp2020-21111","DOIUrl":"https://doi.org/10.1115/pvp2020-21111","url":null,"abstract":"\u0000 Anisotropic tensile and compressive properties of base metals and girth welds of two API X70 spiral welded pipes have been investigated in this study. Spiral welded pipes exhibit different characteristics of anisotropy with respect to pipe axis in comparison with UOE pipes, as the anisotropic property is determined by the thermo-mechanical rolling process of plates and coils produced for pipes. Yield strengths measured from respective tensile and compressive tests are quite comparable at a given material and orientation, although tensile yield strengths are somewhat greater. The results of compressive tests also indicate an anisotropy in the through-thickness direction as well as in the longitudinal direction; high yield strengths are observed at the through-thickness direction or nearby for both base metals and girth welds of the two pipes.","PeriodicalId":396247,"journal":{"name":"Volume 6: Materials and Fabrication","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122172359","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}

{"title":"Investigation of Temperature Dependence of Weibull Parameters of the Beremin Model in Ductile-Brittle Transition Temperature Region","authors":"Kiminobu Hojo, N. Ogawa, K. Yoshimoto, T. Hirota, Yasuto Nagoshi","doi":"10.1115/pvp2020-21651","DOIUrl":"https://doi.org/10.1115/pvp2020-21651","url":null,"abstract":"\u0000 The Beremin model can handle both the plastic constraint effect and data scatter for brittle fracture. Many researchers have been investigating its applicability for more than 30 years and are still discussing the temperature dependence of Weibull parameters used in this model. The authors have already presented the experimental and analytical investigation results for low alloy steel using C(T) specimens in several temperature conditions. The analysis suggested that the Weibull parameters are constant for temperature. In this paper fracture toughness tests of carbon steel using SE(B) specimens at −120°C and −50°C were performed and the Weibull parameters were determined by the test results at −120°C. KJc of the 5% lower bound and the 95% upper bound confidence limit at −50°C were predicted using the Weibull parameters from −120°C. As a result, the predicted 5% lower bound confidence limit was close to the lowest experimental KJc value, whose fracture mode was nearly cleavage fracture. This means there is no temperature dependency of the Weibull parameters and the results are similar to those of low alloy steel. On the other hand the predicted 95% upper bound confidence limit had a large gap when compared with the experimental upper KJc value. One of the reasons of large gap was estimated that the parameter fitting of the GTN model was performed without consideration of the parameters relating to the second void effect and a precise stress-strain field after a large ductile crack growth with several millimeters was not obtained.","PeriodicalId":396247,"journal":{"name":"Volume 6: Materials and Fabrication","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134591953","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}

{"title":"Evaluation of Mechanical and Corrosion Properties of Base Metal and HAZ Having ASS 304L Forgings Containing Ferrite","authors":"Ritesh Patel, Hardik Shah, Jimmy Dutt","doi":"10.1115/pvp2020-21254","DOIUrl":"https://doi.org/10.1115/pvp2020-21254","url":null,"abstract":"\u0000 Austenitic Stainless Steel type 304L is being widely used for fabrication due to excellent corrosion resistance and good weldability. Ferrite (3–10%) is needed in weld metal to prevent hot cracking during welding, however, base metal should preferably not contain any ferrite. It is observed that thick forged SS304L components may have small percentage of ferrite depending on the chemical composition, forging parameters including intermediate soaking cycle and final solution annealing heat treatment cycle. Little study or information is available on effect of ferrite in base metal on weld/Heat Affected Zone (HAZ) properties.\u0000 Present study is aimed to evaluate mechanical and corrosion properties of weldment produced with base metal containing 2–4% of ferrite. Forged tubes with two different levels of delta ferrite, with < 0.5% & 2–4%, were welded to Plates with < 0.5% delta ferrite using Mechanized Gas Tungsten Arc Welding (GTAW) process with Inner Bore Welding Technique. Tensile test, Impact test and Hardness test were performed on base metal & HAZ in as-welded condition for both the cases. Microstructure examination in HAZ and Intergranular Corrosion (IGC) test were also performed for both the cases. Results of mechanical tests, microstructure examination and IGC test have been compared between base metal/HAZ of < 0.5% and 2–4% Ferrite base metal. No significant difference has been observed in test result of tubes with 2–4% delta ferrite as compared to tubes with < 0.5% delta ferrite.","PeriodicalId":396247,"journal":{"name":"Volume 6: Materials and Fabrication","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126266893","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}

{"title":"Stainless Steel Pipe Welding With No Backing Gas","authors":"V. Rajan, B. Narayanan, M. Barrett, Kevin Beardsley","doi":"10.1115/pvp2020-21799","DOIUrl":"https://doi.org/10.1115/pvp2020-21799","url":null,"abstract":"\u0000 For pipe fabrication shops, stainless steel pipe welding typically represents 15%–20% of their business. The pipe materials fabricated in these shops are primarily austenitic stainless 304L and 316L pipe. The quality requirements in stainless pipe fabrication shops are determined by performance requirements for service applications in low temperature, high temperature or corrosive environments. To enable the performance required in these applications, codes, standards and recommended practices for welding are frequently written from a conventional GTAW or SMAW welding paradigm. In addition, for the root pass and the first fill pass made with GTAW, an inert backing gas is always recommended to minimize or eliminate the discoloration or oxidation on the ID surface of the pipe near the root pass. The use of GTAW with inert backing gas adds significant time, complexity and cost to the welding of stainless pipe. In stainless pipe shop fabrication, very few welding practices recognize or encourage the use of GMAW welding solutions for these applications, even though it is known to be a more productive and economical welding process. Moreover, the absence of a consistent and proven GMAW welding solution in terms of either no backing gas GMAW, alternative options for expensive shielding gases, implementing unique welding waveforms etc., proves to be a hindrance in the adoption of GMAW solutions for the welding of stainless pipe.\u0000 In this paper, we discuss advances that have been made in producing acceptable stainless pipe welds with a 1G GMAW welding solution using an STT® waveform for the root pass and a unique “Rapid X™” waveform for fill passes with no use of backing gas. One goal of this project was to also find a shielding gas mixture to provide acceptable welds from root to cap that takes into account both welding process performance as well as fabrication of defect free welds. Six different shielding gas mixtures with varying amounts of Ar, He, CO2 and N2 were evaluated. Results indicate that STT/RAPID X™ welds made with 97%Ar/2%CO2/1%H2 provide very promising results in terms of weld appearance and other conventional metrics such as radiography, bends and tensile properties. However, assessment of the corrosion performance in comparison to welds made with conventional GTAW requires development of a better test protocol than the ASTM G48 Method A test for it to be relevant and meaningful.","PeriodicalId":396247,"journal":{"name":"Volume 6: Materials and Fabrication","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121080215","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}

{"title":"Damage Assessment of Similar Martensitic Welds Under Creep, Fatigue and Creep-Fatigue Loading","authors":"Thorben Bender, A. Klenk, S. Weihe","doi":"10.1115/pvp2020-21497","DOIUrl":"https://doi.org/10.1115/pvp2020-21497","url":null,"abstract":"\u0000 For the assessment of welds under high-temperature conditions in the creep or creep-fatigue regimes, the knowledge on the damage location and its temporal evolution are of high importance. The failure behavior of similar welds of ferritic-martensitic steels in the creep regime is well known. For creep-fatigue loading, the behavior of welds is still subject to research but it seems that the heat affected zone (HAZ) limits the lifetime of welded components as well. This local failure behavior is not reflected in design guidelines using weld reduction factors or in typical assessment approaches. The evaluation of local strains and stresses in the HAZ is unavoidable. For the improvement of design and inspection guidelines, a more detailed consideration of weld behavior is of interest.\u0000 In this paper, an overview of current developments in the assessment of welds under creep, fatigue, and creep-fatigue loading conditions is given. An assessment approach for creep damage and failure, including the prediction of rupture time and location, is presented. The assessment is based on numerical analyses considering the different behavior of base material and HAZ represented by three different subzones. The approach is validated with the simulation of a uniaxial cross weld, creep crack, and component tests. Whereas the creep behavior of the HAZ compared to base metal is quite well known, there is only little knowledge of their fatigue behavior. Using a set of fatigue tests on HAZ, base metal specimens and cross weld specimens, the influence of fatigue and creep-fatigue loading on the lifetime and failure location of a weld will be discussed. For the numerical simulations, a viscoplastic material law of Chaboche type is used and an evaluation of the local strains in the HAZ allows an attempt to explain the observed failure locations.","PeriodicalId":396247,"journal":{"name":"Volume 6: Materials and Fabrication","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116787232","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}

{"title":"The Role of Grain Boundary Orientation and Secondary Phases in Creep Cavity Nucleation of a 316H Boiler Header","authors":"Tomas L Martin, Siqi He, A. Warren, H. Shang, D. Knowles, P. Flewitt","doi":"10.1115/pvp2020-21791","DOIUrl":"https://doi.org/10.1115/pvp2020-21791","url":null,"abstract":"\u0000 Cavity formation during creep of steels at high temperatures and stresses is closely related to the original and evolved microstructure, particularly the orientation between grains and precipitation at the grain boundaries. Understanding the initiation, growth and coalescence of creep cavities is critical to determining the operational life of components in high temperature, high stress environments such as an advanced gas-cooled nuclear reactor. However, accelerated laboratory-based testing frequently shows another kind of void within the microstructure, caused by plastic damage and ductile failure, particularly if a specimen fails during a test. This paper compares the type of voids and cavities observed in an AISI 316 stainless steel after extensive service in a gas-cooled nuclear reactor boiler header and after uniaxial creep testing of a similar material at higher stresses. The differences between the features observed and their potential mechanistic origins are discussed.","PeriodicalId":396247,"journal":{"name":"Volume 6: Materials and Fabrication","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129282907","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}

{"title":"Dynamic Performance Analysis of Interfacial Cracks Near an Eccentric Elliptical Hole in Piezoelectric Bi-Materials Under Incident SH-Waves","authors":"Ni An, Tian-shu Song, Ming Zhao, Liu Yu, G. Hou","doi":"10.1115/pvp2020-21213","DOIUrl":"https://doi.org/10.1115/pvp2020-21213","url":null,"abstract":"\u0000 Piezoelectric materials have been widely used in modern science and technology due to their electro-mechanical coupling response. Sometimes, because of the stiff and brittle nature of some piezoelectric materials, the piezoelectric devices with defects may face fracture or failure during their service procedures. Therefore, it has become important to investigate the failure behaviors caused by defects, such as cracks and holes.\u0000 Based on the study of the dynamic anti-plane characteristics for radial crack emanating from a circular cavity in piezoelectric bi-materials, this paper aims to analyzes the dynamic incident anti-plane shearing (SH-wave) in piezoelectric bi-materials, which contains two interfacial cracks, near an eccentric elliptical hole. Green’s function method, the conformal mapping method, the interface conjunction techniques and the crack-deviation techniques are utilized to obtain a series of first kind Fredholm’s equations, based on which the dynamic stress intensity factor (DSIF) at the outer and the inner cracks’ tips are theoretically expressed. Numerical examples were graphically presented to illustrate the effects of the piezoelectric parameter, the effective piezoelectric elastic modulus, the dimensionless incident wave number and geometric parameters on the DSIF at both of the tips.\u0000 Previous studies are not comprehensive, especially when the center of the hole deviates from the interface. Therefore, the impact of eccentric distance on DSIF is considered in this paper. The solution of this problem provides a more accurate and efficient method for the investigation of dynamic fracture properties of piezoelectric materials and has an important theoretical significance in engineering design.","PeriodicalId":396247,"journal":{"name":"Volume 6: Materials and Fabrication","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126578615","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}