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Sample records for api grade steel

  1. Mechanical Characteristics of Submerged Arc Weldment in API Gas Pipeline Steel of Grade X65

    International Nuclear Information System (INIS)

    Hashemi, S. H.; Mohammadyani, D.

    2011-01-01

    The mechanical properties of submerged arc weldment (SAW) in gas transportation pipeline steel of grade API X65 (65 ksi yield strength) were investigated. This steel is produced by thermo mechanical control rolled (TMC), and is largely used in Iran gas piping systems and networks. The results from laboratory study on three different regions; i.e. base metal (BM), fusion zone (FZ) and heat affected zone (HAZ) were used to compare weldment mechanical characteristics with those specified by API 5L (revision 2004) standard code. Different laboratory experiments were conducted on test specimens taken from 48 inch outside diameter and 14.3 mm wall thickness gas pipeline. The test results showed a gradient of microstructure and Vickers hardness data from the centerline of FZ towards the unaffected MB. Similarly, lower Charpy absorbed energy (compared to BM) was observed in the FZ impact specimens. Despite this, the API specifications were fulfilled in three tested zones, ensuring pipeline structural integrity under working conditions.

  2. Construction and assembly of pipelines using API 5L grade X80 tubes - considerations to be observed with high-strength steels; Construcao e montagem de dutos terrestres utilizando tubos API 5L Gr. X80

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Ailton C. de; Rabello, Jose Mauricio B. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)

    2005-07-01

    The use of line pipes API 5L Grade X80, at the point of view of designer allows: reduction of wall thickness and pipe weight or increase of design pressure. In the pipeline construction point of view, the use of line pipes API 5L Grade X80 provide some advantages, however some difficulties must be expected in several stages of the construction and assembly. The implications in cost, productivity, inspection and integrity, with the application of these high resistance steels, complying with PETROBRAS Standard N - 464 Construcao, Montagem e Condicionamento de Dutos Terrestres (Rev. H - 2004 Dec) and the experience consolidated in pipelines construction abroad were presented. At the design stage, a comparison between pipelines designed using API 5L-X70 and API 5L-X80 was carried out approaching the aspects of variation of thickness, pressure design and design factor. An evaluation of the expected gains when choosing API 5L Grade X80 steels were done, regarding reduction of costs and pipe weight. Regarding API 5L-X80 pipe fabrication, the obtained results were reported, proving that this aspect was already overcome, showing the viability of its production in Brazil. Difficulties were detected regarding construction and assembly stage and showing the need of revision of PETROBRAS standard N-464. (author)

  3. Development of API 5 CT grade P110 steel casing; Desenvolvimento de tubos casing API 5 CT grau P110

    Energy Technology Data Exchange (ETDEWEB)

    Kojima, Sergio Seijo; Roza, Juliana Espinossi

    2003-07-01

    This paper has as objective to discuss the results gotten in experiences carried through in industrial scale for the development of pipes class API 5CT P110 (1), with 244 mm of diameter and 12 mm of thickness. The pipes were welded longitudinally by process ERW (electric resistance welding) and submitted to quenching and tempering heat treatments. A C-Mn-Cr alloy with adequate quenching ability was used for the attainment of a martensite microstructure after quenching. The pipes at a temperature of 880 deg C were quenched in water and subsequently tempered at 515 deg C. The integrity of the weld region was evaluated through non destructive tests and flattening tests, Charpy impact tests and fracture toughness tests (CTOD). The pipes achieved the tension properties stipulated in the standard (yield strength bigger limit of 758 Mpa), and also the energy in the Charpy impact test (transversal), considering that the energy value obtained was 55 J (at 0 deg C) for base metal and 44 J in the weld metal. (author)

  4. Temperature effect on API grade steels in CO{sub 2} environments

    Energy Technology Data Exchange (ETDEWEB)

    Martins, F.A; Bott, I. [Catholic University of Rio de Janeiro, Metallurgical and Materials Science Department, DCMM/PUC RJ, Rio de Janeiro (Brazil); Rodrigues, A.P.C.; Reznik, L.Y.; Freitas, D.S. de [National Institute of Technology, Corrosion and Degradation Department, DCOR/INT (Brazil)

    2004-07-01

    There is urgency in optimising and to widen the resources for corrosion control to minimise problems regarding failure and leakage in pipelines. The corrosion control is especially important as it is increasingly associated with mechanical integrity. This means that there is an effort to produce alloys with better mechanical properties which consequently will gradually reduce the thickness of the pipeline walls. However it is necessary to bear in mind that internal corrosion occurs and it can compromise the use of these materials. This is so because as long as the wall thickness is diminished, the corrosion can lead to catastrophic failures and reduce tubes life-time significantly. Therefore, it is necessary to study the behaviour of the steel in critical environments to understand and to obtain a better performance, and moreover, to predict their corrosion rates. The aim of this project is to study the behaviour of the steel X70 and X80 grade, base metal and welded joints, in CO{sub 2} environment. The main focus will be in the stability of iron carbonate film as function of temperature. The methodology of this study will involve several tests and analyses. Electrochemical tests will be carried out in a second part of this work to assess the film formation and to determine, in comparison with gravimetric tests, the corrosion rate. The morphology attack will be determined and metallographic analysis will be carry out to evaluate the steel microstructure. Complementary analysis will be accomplished using SEM/EDX and x-rays diffraction. It is expected to obtain information about the temperature range in which the iron carbonate film on X70 and X80 steels is stable, in such way that it will improve their application. The results of this project will contribute to the leakage control technology in pipelines. Moreover, it will permit a real recommendation of the wall thickness of pipelines to be employed in field, which in return will provide an augment of guarantee in

  5. Corrosion resistance of API 5L grade B steel with taro leaf (Colocasia esculenta) addition as corrosion inhibitor in HCl 0.1 M

    Science.gov (United States)

    Lestari, Yulinda; Priyotomo, Gadang

    2018-05-01

    Taro leaf (Colocasia esculenta) has the potential to be used as a corrosion inhibitor because it has a substance called polyphenol that binds to the hydroxyl group and essential amino acids. Taro leaf extract is taken by maceration method. In this study, the specimen was steel API 5L grade B that would measured the corosivity in 0.1 M HCl solution + taro leaf extract with a specific concentration (in ppm). Tests conducted by FTIR method taro leaves, potentiodynamic polarization (Tafel) and Electrochemical Impedance Spectroscopy (EIS). Based on the results revealed that there is a phenolic group in taro leaves, which has polyphenol content 0.053 % (mg/100 mg). The optimum composition of taro leaf extract is 4000 ppm which generate corrosion rate value of 30.22 mpy and efficiency inhibitor performance of 72.7 %. In this study, the Kads value of taro leaf extract ranged from 0.885 to greater than Kads value of ginger extract in hydrochloric acid solution. The high Kads values indicate a more efficient process of adsorption and better value of inhibition efficiency.

  6. Gaseous hydrogen embrittlement of an API X80 ferrito-pearlitic steel; Fragilisation par l'hydrogene gazeux d'un acier ferrito-perlitique de grade API X80

    Energy Technology Data Exchange (ETDEWEB)

    Moro, I.

    2009-11-15

    This work deals with hydrogen embrittlement, at ambient temperature and under a high pressure gaseous way, of an API X80 high elasticity limit steel used for pipelines construction, and with the understanding of the associated physical mechanisms of the embrittlement. At first has been described a bibliographic study of the adsorption, absorption, diffusion, transport and trapping of hydrogen in the steels. Then has been carried out an experimental and numerical study concerning the implantation in the finite element code CASTEM3M of a hydrogen diffusion model coupled to mechanical fields. The hydrogen influence on the mechanical characteristics of the X80 steel, of a ferrito-pearlitic microstructure has been studied with tensile tests under 300 bar of hydrogen and at ambient temperature. The sensitivity of the X80 steel to hydrogen embrittlement has been analyzed by tensile tests at different deformation velocities and under different hydrogen pressures on axisymmetrical notched test specimens. These studies show that the effect of the hydrogen embrittlement vary effectively with the experimental conditions. Moreover, correlated with the results of the tests simulations, it has been shown too that in these experimental conditions and for that steel, the hydrogen embrittlement is induced by three different hydrogen populations: the hydrogen trapped at the ferrite/perlite interfaces, the hydrogen adsorbed on surface and the reticular hydrogen trapped in the material volume. At last, the tensile and rupture tests of specimens, during which atmosphere changes have been carried out, have shown a strong reversibility of the hydrogen embrittlement, associated with its initiation as soon as hydrogen is introduced in the atmosphere. At last, three hydrogen mechanisms, depending of the different hydrogen populations are presented and discussed. (O.M.)

  7. Circumferential welding of API X80 steel pipes; Soldagem circunferencial em tubos de aco da classe API X80

    Energy Technology Data Exchange (ETDEWEB)

    Castello Branco, J.F.; Bott, Ivani de S. [Pontificia Univ. Catolica do Rio de Janeiro, RJ (Brazil). Dept. de Ciencia dos Materiais e Metalurgia]. E-mails: joaofcb@uol.com.br; bott@dcmm.puc-rio.br; Fedele, R.A. [Boehler Thyssen Welding, Sao Paulo, SP (Brazil)]. E-mail: engenharia@btwbr.com.br; Souza, Luis Felipe G. de [Centro Federal de Educacao Tecnologica Celso Suckow da Fonseca (CEFET-RJ), Rio de Janeiro, RJ (Brazil). Dept. de Engenharia Industrial Mecanica]. E-mail: lfelipe@cefet-rj.br

    2003-07-01

    The present work is a part of an extensive program for the development of API 5L Gr.X80 grade steel , produced by the well-known UOE production process, for pipeline fabrication. The current stage of this program involves the characterization and performance evaluation/qualification of girth welds produced by Shield Metal Arc Weld (SMAW) under simulated field conditions, with tubes fixed in the horizontal position. Three types of electrodes were utilized for the basic tasks; the root pass, the hot pass and fill and cap passes. The root pass was carried out with an E-6010 electrode to avoid incomplete joint penetration. The hot pass, applied over the root pass, was performed with an E-9010-G electrode. The fill and cap passes were executed with E-10018-G electrodes. The welded joints produced were evaluated according to the API 1104 specification, which requires: side bend, nick- break and tensile tests. Additionally, non-destructive tests, Charpy-V impact tests and metallographic characterization were undertaken. It was verified that this welding procedure, based on three types of electrodes, could produce welded joints in accordance to the API 1104 specification. These results ensure the applicability of the API 5L Gr. X80 steel developed in this research project for use in pipeline construction. (author)

  8. Characterisation of weldment hardness, impact energy and microstructure in API X65 steel

    International Nuclear Information System (INIS)

    Hashemi, S.H.; Mohammadyani, D.

    2012-01-01

    The variation of microstructure and mechanical properties in various sub-zones of double submerged arc welded line pipe steel of grade API X65 was investigated. Instrumented Charpy V-notch tests and Vickers hardness experiments were conducted on the fusion zone, base metal and heat affected zone of the weld joint in 14.3 mm thick, 1219 mm outside diameter spiral pipeline. The lowest impact energy and the highest hardness level (160J and 218 HV, respectively) were recorded in the fusion zone. The low energy and high hardness characteristics of the seam weld can be attributed to its cast microstructure and the presence of grain boundary phases (such as proeutectoid ferrite), confirmed by standard metallographic observation. Despite this, service requirements set by the API 5L industry code (minimum impact energy of 73J, maximum hard spots of 350 HV) were fulfilled by the tested steel. Highlights: ► Experimental study of API X65 steel microstructure. ► Analysis of the relationship between X65 steel microstructure and hardness. ► Analysis of the relationship between X65 steel microstructure and impact energy. ► Presentation of detailed technical information on DSA welding in spiral pipes.

  9. Functionally Graded Mo sintered steels

    Directory of Open Access Journals (Sweden)

    Manuel Cisneros-Belmonte

    2016-12-01

    Full Text Available Functionally graded materials (FGM, the multi-materials, strive to satisfy the numerous requirements demanded of parts in a given combination of compositions and microstructures. The required material compatibility lead the manufacturing process and the achieving of an interface, not always diffuse. Powder metallurgy is one of the techniques used in manufacturing functionally graded materials, in particular the compaction matrix of the possible techniques for forming these materials. In this paper, a process of forming a functionally graded steel based on the use of a high molybdenum steel with cooper and other steel with copper, without molybdenum, is proposed with the aim of concentrating this element to the surface of the workpiece, increasing the mechanical strength. The study is completed with the evaluation of physical properties (density and porosity distribution, mechanical properties (hardness, tensile strength and elongation and microstructural analysis by optical and scanning electron microscopy.

  10. Sensitivity Analysis of Fatigue Crack Growth Model for API Steels in Gaseous Hydrogen.

    Science.gov (United States)

    Amaro, Robert L; Rustagi, Neha; Drexler, Elizabeth S; Slifka, Andrew J

    2014-01-01

    A model to predict fatigue crack growth of API pipeline steels in high pressure gaseous hydrogen has been developed and is presented elsewhere. The model currently has several parameters that must be calibrated for each pipeline steel of interest. This work provides a sensitivity analysis of the model parameters in order to provide (a) insight to the underlying mathematical and mechanistic aspects of the model, and (b) guidance for model calibration of other API steels.

  11. APIs

    CERN Document Server

    Jacobson, Daniel; Woods, Dan

    2011-01-01

    Programmers used to be the only people excited about APIs, but now a growing number of companies see them as a hot new product channel. This concise guide describes the tremendous business potential of APIs, and demonstrates how you can use them to provide valuable services to clients, partners, or the public via the Internet. You'll learn all the steps necessary for building a cohesive API business strategy from experts in the trenches. Facebook and Twitter APIs continue to be extremely successful, and many other companies find that API demand greatly exceeds website traffic. This book offe

  12. Development of stress-modified fracture strain criterion for ductile fracture of API X65 steel

    International Nuclear Information System (INIS)

    Oh, Chang Kyun; Kim, Yun Jae; Park, Jin Moo; Kim, Woo Sik; Baek, Jong Hyun

    2005-01-01

    This paper presents a stress-modified fracture strain for API X65 steel used for gas pipeline, as a function of stress triaxiality. To determine the stress-modified fracture strain, tension test of bars with four different notch radii, made of API X65 steel, is firstly performed, from which true fracture strains are determined as a function of notch radius. Then detailed elastic-plastic, large strain Finite Element (FE) analyses are performed to estimate variations of stress triaxiality in the notched bars with load. Combining experimental with FE results provides the true fracture strain as a function of stress triaxiality, which is regarded as a criterion of ductile fracture. Application of the developed stress-modified fracture strain to failure prediction of gas pipes made of API X65 steel with various types of defects is discussed

  13. Validation of methods for WDXRF and OES-spark techniques in steel analysis. Determination of the uncertainty of measurements for API steel plant sample

    International Nuclear Information System (INIS)

    Silva, Carlos Eduardo da

    2009-01-01

    The increase of gas and petroleum demanding in the national and international markets, the specification and certification of the chemical analysis results of gas and oil pipe-line have became more and more challenging. A continuous development has been outlined to improve API grade alloy steels (American Petroleum Institute). The steel properties depend on the chemical composition control and process parameters during its manufacturing. In this work, a comparison of the measurement uncertainty between X-ray fluorescence (WD system) and Optical Emission (OES-spark) spectrometry, for API grade steel plant samples analysis, was outlined. Usually, this kind of analyze requires less than 40 seconds for full chemical characterization for adjustment in the process parameters production. The main influence source in the chemical analysis was evaluated for design of experiments. The constituents and trace elements such as Al, Si, P, S, Ti, V, Cr, Mn, Co, Ni, Cu, As, Nb, Mo and Sn were determined using the ASTM E-322, E-415, E-1009 and E-1085 standard methodologies. The 185A and 187A certified reference materials from CMI (Czech Metrology Institute) were used for evaluation of the methods. The uncertainty of the measurement, precision, accuracy, repeatability and reproducibility of the measurements were obtained applying statistic tests, recommended by ISO/IEC 17025. The uncertainty of measurement for each element is discussed for both techniques. (author)

  14. EBSD study of hydrogen-induced cracking in API-5 L-X46 pipeline steel

    International Nuclear Information System (INIS)

    Venegas, V.; Caleyo, F.; Gonzalez, J.L.; Baudin, T.; Hallen, J.M.; Penelle, R.

    2005-01-01

    The spatial distribution of plastic deformation and grain orientation surrounding hydrogen-induced cracks (HIC) is investigated in samples of API-5L-X46 pipeline steel using scanning electron microscopy and electron backscattering diffraction (EBSD). This work shows direct experimental evidence of the influence of microstructure, microtexture and mesotexture on HIC crack path

  15. Investigations of corrosion films formed on API-X52 pipeline steel in acid sour media

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Espejel, A. [Instituto Politecnico Nacional, Departamento de Ingenieria Metalurgica, IPN-ESIQIE, UPALM Ed. 7, Zacatenco 07738, Mexico, D.F. (Mexico); Dominguez-Crespo, M.A. [Instituto Politecnico Nacional, CICATA-Unidad Altamira-Tamaulipas, km 14.5, Carretera Tampico-Puerto Industrial Altamira, 89600 Altamira, Tamps (Mexico); Cabrera-Sierra, R. [Instituto Politecnico Nacional, Departamento de Ingenieria Quimica Industrial, IPN-ESIQIE, UPALM Ed. 7, Zacatenco 07738, Mexico, D.F. (Mexico); Rodriguez-Meneses, C. [Instituto Politecnico Nacional, Departamento de Ingenieria Metalurgica, IPN-ESIQIE, UPALM Ed. 7, Zacatenco 07738, Mexico, D.F. (Mexico); Arce-Estrada, E.M., E-mail: earce@ipn.m [Instituto Politecnico Nacional, Departamento de Ingenieria Metalurgica, IPN-ESIQIE, UPALM Ed. 7, Zacatenco 07738, Mexico, D.F. (Mexico)

    2010-07-15

    Corrosion films formed by voltammetry using different switching potentials and by immersion on API-X52 pipeline steel in simulated acid sour media (NACE ID182) have been characterized using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Linear Polarization and Electrochemical Impedance Spectroscopy (EIS) techniques. XRD and EDS analysis showed that the films are mainly composed of sulphide compounds (mackinawite, troilite, marcasite and pyrite) as well as iron oxides, as steel damage increases. Across SEM micrographs the corrosion films formed by potentiodynamic and immersion tests are very similar, covering most of the steel. Polarization and EIS results corroborate poor behavior against corrosion.

  16. Investigations of corrosion films formed on API-X52 pipeline steel in acid sour media

    International Nuclear Information System (INIS)

    Hernandez-Espejel, A.; Dominguez-Crespo, M.A.; Cabrera-Sierra, R.; Rodriguez-Meneses, C.; Arce-Estrada, E.M.

    2010-01-01

    Corrosion films formed by voltammetry using different switching potentials and by immersion on API-X52 pipeline steel in simulated acid sour media (NACE ID182) have been characterized using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Linear Polarization and Electrochemical Impedance Spectroscopy (EIS) techniques. XRD and EDS analysis showed that the films are mainly composed of sulphide compounds (mackinawite, troilite, marcasite and pyrite) as well as iron oxides, as steel damage increases. Across SEM micrographs the corrosion films formed by potentiodynamic and immersion tests are very similar, covering most of the steel. Polarization and EIS results corroborate poor behavior against corrosion.

  17. Determination of Burst Pressure of API Steel Pipes using Stress Modified Critical Strain Model

    International Nuclear Information System (INIS)

    Alang, N A; Razak, N A; Sulaiman, A S

    2012-01-01

    This paper presents a technique which can be used to determine the burst pressure of defective steel pipes using non-linear finite element (FE) analysis. The technique uses stress modified critical strain (SMCS) failure criterion to study the effect of gouge defects on maximum working pressure of API X65 steel pipes. The procedures in determining the model parameters using 3-D, homogeneous isotropic elastic-plastic material model with large deformation finite element analyses from notched tensile bars were systematically discussed. The relationship between burst pressure and gouge depth was proposed. The burst pressure estimated then was compared to experimental data from the literature for validation showing overall good agreements.

  18. Development of nuclear grade stainless steels at KCSSL

    International Nuclear Information System (INIS)

    Balachandran, G.; Dhere, M.; Mahadik, A.; Hinge, N.M.; Balasubramanian, V.

    2011-01-01

    Kalyani Carpenter Special Steels Ltd is an alloy steel plant, where a variety of alloy steel grades are produced for automotive, defence, nuclear and aerospace applications. The plant has developed expertise in processing of several alloy steel grades of superior quality that meets stringent specifications. Primary steel is processed through a combination of electric arc furnace, ladle furnace and vacuum degassing where stringent control over dephosphorisation, desulphurization, deoxidation is effected to get a refined high quality steel. The molten steel is cast through continuous casting of slabs or ingot casting. In grades specific to nuclear application, the primary cast products are further subjected to electroslag remelting to achieve further freedom from inclusions and to achieve a favourable solidification grain structure, which ultimately improve the hot workability of the alloy steel. Appropriate choice of slag and operating parameters are needed for realising the required ingot quality. The present study would examine the processing and quality aspects of some important grades of steels used in nuclear industry namely ferritic 9Cr-1Mo steel, martensitic stainless steels 403, 410, precipitation hardenable 17-4 PH stainless steel and austenitic 321, 316LN stainless steel, which were made and supplied for applications to Indian nuclear industry. The expertise developed in processing the steels in terms of melting, heat treatment and their relationship to structural features and mechanical properties would be highlighted. (author)

  19. Chemical and microstructural diversity of steel grades

    Directory of Open Access Journals (Sweden)

    Zorc, B.

    2002-12-01

    Full Text Available The aim of the paper is to show, using theoretical and practical analyses, chemical and microstructural differences among individual types of steel grades 355 found in the market. The mechanical properties required for these steels are achieved by alloying or thermomechanical treatment. It was found that the individual types of this steel are poorly weldable, particularly those of large thickness.

    El objetivo del artículo es presentar, en base a un análisis teórico y práctico, las diferencias químicas y microestructurales entre los diferentes tipos de aceros calidad 355 que pueden encontrarse en el mercado. Las características mecánicas requeridas en estos aceros se consiguen con aleaciones, o bien a través de tratamientos termo-mecánicos.Se ha llegado a la conclusión de que determinados tipos de acero son más difíciles de soldar, en especial cuando se trata de espesores grandes.

  20. Correction factors for safe performance of API X65 pipeline steel

    International Nuclear Information System (INIS)

    Hashemi, Sayyed H.

    2009-01-01

    Prediction of required Charpy energy for fracture arrest is vital for safe performance of gas transportation pipelines. This is commonly estimated through failure models calibrated in the past on fracture data from combined Charpy tests and full-thickness burst experiments. Unfortunately, such pipeline failure models are unable to correctly predict the minimum arrest toughness of thermo-mechanical controlled rolled (TMCR) steels. To refine the existing failure models, different empirical adjustments have been proposed in recent years. In this paper, similar correction factors were derived from fracture information of instrumented Charpy impact tests on API X65 steel. The contribution of different fracture mechanisms of impact test specimens was determined through energy partitioning analysis. Parts of the energy contribution were correlated then to the source of uncertainty observed in similar experiments. The applied technique was similar to that of previous studies on X70 and X100 steels, and proved to be encouraging in giving consistent results compared to available test data.

  1. Erosion Behaviour of API X100 Pipeline Steel at Various Impact Angles and Particle Speeds

    Directory of Open Access Journals (Sweden)

    Paul C. Okonkwo

    2016-09-01

    Full Text Available Erosion is the gradual removal of material due to solid particle impingement and results in a failure of pipeline materials. In this study, a series of erosion tests were carried out to investigate the influence of particle speed and impact angle on the erosion mechanism of API X100 pipeline steel. A dry erosion machine was used as the test equipment, while the particle speed ranged from 20 to 80 m/s and impact angles of 30° and 90° were used as test parameters. The eroded API X100 steel surface was characterized using scanning electron microscope (SEM and X-ray photoelectron spectroscopy (XPS. The weight loss and erosion rate were also investigated. The results showed that at a 90° impact angle, a ploughing mechanism was occurring on the tested specimens, while material removal through low-angle cutting was the dominant mechanism at lower impact angles. Embedment of alumina particles on the target steel surface, micro-cutting, and low-angle cutting were observed at low impact angles. Therefore, the scratches, cuttings, and severe ploughings observed on some failed oil and gas pipelines could be attributed to the erosion mechanism.

  2. The effect of hot strip mill processing parameters and alloy addition on low temperature toughness of API-X70 steel

    Energy Technology Data Exchange (ETDEWEB)

    Ro, Kwang Seop; Al-Shammary, Saad; Al-Butairi, Adel A. [QA and PTS, SAUDI IRON and STEEL COMAPNY, Al-Jubail, (Saudi Arabia); Al-Hajeri, Khaled F. [Saudi Basic Industries Corporation, Jubail, (Saudi Arabia)

    2010-07-01

    The design of high strength steel grade is based on stringent specifications in terms of chemistry, mechanical properties and surface requirements. This study investigated the effect of alloy addition on low temperature toughness of API X70 pipeline steel. Seven different chemical compositions have been selected for experimental testing. Ni, Cr and Cu were added in various quantities to the tested material without deteriorating the phase transformation to acicular ferrite. A tensile test, Charpy impact test, DWTT pressed notch test and microstructural observations using optical microscope and SEM were carried out. Statistical analyses were done to identify the relationship between chemical composition and DWTT shear area. The following equation showed excellent agreement with the experimental test data: Pct Shear aero of DWTT (-10 degrees C) = 954 - 0.3*SRT + 0.5*TBT - 0.4*FRT + 0.04*CT - 306*C - 60*(Mn+Ni+Cu) + 38*(Mo+Cr) - 791*(Ti+Nb+V) - 4*MA. The results showed that it is possible to design high strength API X 70 steel grades with good DWTT toughness by using the statistical equation that was developed.

  3. Corrosion of API XL 52 steel in presence of Clostridium celerecrescens

    Energy Technology Data Exchange (ETDEWEB)

    Monroy, O.A. Ramos; Ordaz, N. Ruiz; Ramirez, C. Juarez [Escuela Nacional de Ciencias Biologicas, Instituto Politecnico Nacional, Prolongacion de Carpio y Plan de Ayala, Mexico D. F., C. P. 11340 (Mexico); Gayosso, M.J. Hernandez; Olivares, G. Zavala [Instituto Mexicano del Petroleo, Grupo Corrosion, Eje Central Lazaro Cardenas 152, Col. San Bartolo Atepehuacan, Mexico D. F., C. P. 07730 (Mexico)

    2011-09-15

    During the characterization of sediments formed in pipelines transporting hydrocarbons, the knowledge of the microbiological diversity becomes very interesting, especially when it is related to microbiologically influenced corrosion (MIC). The presence of microorganisms is considered as one of the factors that affect the corrosion processes occurring at the pipeline; therefore, their corrosiveness must be determined. In this way, the identification of new species affecting the MIC processes is still considered relevant. In this work, the effect of Clostridium celerecrescens upon the corrosion of API KL 52 steel was evaluated. This microorganism was isolated and identified from the sediments collected during the inner cleaning procedures of a gas pipeline. The polarization resistance (PR) and electrochemical impedance spectroscopy (EIS) techniques were considered to estimate the microorganism behavior during the corrosion process. The results were complemented with a metal surface analysis, using a scanning electron microscope (SEM). The resistance values induced by the presence of the microorganisms clearly indicated that C. celerecrescens has an effect on the corrosion process occurring at the API XL 52 steel surface. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Effects of C and Si on strain aging of strain-based API X60 pipeline steels

    Science.gov (United States)

    Sung, Hyo Kyung; Lee, Dong Ho; Lee, Sunghak; Lee, Byeong-Joo; Hong, Seung-Pyo; Kim, Young-Woon; Yoo, Jang Yong; Hwang, Byoungchul; Shin, Sang Yong

    2017-05-01

    Four types of strain-based API X60 pipeline steels were fabricated by varying the C and Si contents, and the effects of C and Si on strain aging were investigated. The 0.05 wt% C steels consisted mainly of polygonal ferrite (PF), whereas the 0.08 wt% C steels consisted of acicular ferrite (AF). The volume fraction of AF increased with increasing C content because C is an austenite stabilizer element. The volume fractions of bainitic ferrite (BF) of the 0.15 wt% Si steels were higher than those of the 0.25 wt% Si steels, whereas the volume fractions of the secondary phases were lower. From the tensile properties before and after the aging process of the strainbased API X60 pipeline steels, the yield strength increased and the uniform and total elongation decreased, which is the strain aging effect. The strain aging effect in the strain-based API X60 pipeline steels was minimized when the volume fraction of AF was increased and secondary phases were distributed uniformly. On the other hand, an excessively high C content formed fine precipitates, and the strain aging effect occurred because of the interactions among dislocations and fine precipitates.

  5. Effect of non-metallic inclusions on hydrogen-induced cracking of API5L X100 steel

    Energy Technology Data Exchange (ETDEWEB)

    Jin, T.Y.; Liu, Z.Y.; Cheng, Y.F. [Department of Mechanical and Manufacturing Engineering, University of Calgary, Calgary, Alberta (Canada)

    2010-08-15

    In this work, the type, composition and distribution of inclusions contained in an API5L X100 steel were characterized by scanning electron microscopy and energy-dispersive x-ray analysis. A hydrogen-charging at various current densities was used to introduce hydrogen into the steel, and the correlation between HIC and the inclusions was established. The microstructure of the steel consists of a leather-like bainitic ferrite matrix, with martensite/austenite as the second phase particles. At least four types of inclusions are contained in API5L X100 steel, elongated MnS inclusions and spherical Al-, Si- and Ca-Al-O-S-enriched inclusions. In particular, the majority of inclusions in the steel are Al-enriched. Upon hydrogen-charging, hydrogen blisters and HIC could be caused in the steel in the absence of external stress. The cracks are primarily associated with the Al- and Si-enriched inclusions, rather than the elongated MnS inclusion. The critical amount of hydrogen resulting in HIC of the tested API5L X100 steel is determined to be 3.24 ppm under condition in this work. (author)

  6. Sodium alginate: A promising biopolymer for corrosion protection of API X60 high strength carbon steel in saline medium.

    Science.gov (United States)

    Obot, I B; Onyeachu, Ikenna B; Kumar, A Madhan

    2017-12-15

    Sodium alginate (SA), a polysaccharide biopolymer, has been studied as an effective inhibitor against the corrosion of API X60 steel in neutral 3.5% NaCl using gravimetric and electrochemical techniques (OCP, EIS and EFM). The inhibition efficiency of the SA increased with concentration but was lower at higher temperature (70°C). Electrochemical measurements showed that the SA shifted the steel corrosion potential to more positive value and reduced the kinetics of corrosion by forming an adsorbed layer which mitigated the steel surface wetting, based on contact angle measurement. SEM-EDAX was used to confirm the inhibition of SA on API X60 steel surfaces. The SA adsorbs on the steel surface through a physisorption mechanism using its carboxylate oxygen according to UV-vis and ATR-IR measurements, respectively. This phenomena result in decreased localized pitting corrosion of the API X60 steel in 3.5% NaCl solution. Theoretical results using quantum chemical calculations and Monte Carlo simulations provide further atomic level insights into the interaction of SA with steel surface. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Validation of methods for WDXRF and OES-spark techniques in steel analysis. Determination of the uncertainty of measurements for API steel plant sample; Validacao de metodos para as tecnicas de WDXRF e OES-spark na analise de acos. Calculo de incerteza de medicao para amostras de processo, aco classe API

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Carlos Eduardo da

    2009-07-01

    The increase of gas and petroleum demanding in the national and international markets, the specification and certification of the chemical analysis results of gas and oil pipe-line have became more and more challenging. A continuous development has been outlined to improve API grade alloy steels (American Petroleum Institute). The steel properties depend on the chemical composition control and process parameters during its manufacturing. In this work, a comparison of the measurement uncertainty between X-ray fluorescence (WD system) and Optical Emission (OES-spark) spectrometry, for API grade steel plant samples analysis, was outlined. Usually, this kind of analyze requires less than 40 seconds for full chemical characterization for adjustment in the process parameters production. The main influence source in the chemical analysis was evaluated for design of experiments. The constituents and trace elements such as Al, Si, P, S, Ti, V, Cr, Mn, Co, Ni, Cu, As, Nb, Mo and Sn were determined using the ASTM E-322, E-415, E-1009 and E-1085 standard methodologies. The 185A and 187A certified reference materials from CMI (Czech Metrology Institute) were used for evaluation of the methods. The uncertainty of the measurement, precision, accuracy, repeatability and reproducibility of the measurements were obtained applying statistic tests, recommended by ISO/IEC 17025. The uncertainty of measurement for each element is discussed for both techniques. (author)

  8. Effect of black clay soil moisture on the electrochemical behavior of API X70 pipeline steel

    Science.gov (United States)

    Hendi, R.; Saifi, H.; Belmokre, K.; Ouadah, M.; Smili, B.; Talhi, B.

    2018-03-01

    The effect of moisture content variation (20–100 wt.%) on the electrochemical behavior of API X70 pipeline steel buried in the soil of Skikda (East of Algeria) was studied using electrochemical techniques, scanning electron microscopy (SEM), X ray diffraction analysis (XRD) and weight loss measurement. The electrochemical measurements showed that the corrosion current Icorr is directly proportional to the moisture content up to 50 wt.%, beyond this content, this value becomes almost constant. The result were confirmed by electrochemical impedance spectroscopy; the capacitance of the double layer formed on the surface is the highest at 50 wt.%. A single time constant was detected by plotting the Bode diagrams. The steel surface degradation has been appreciated using the scanning electron microscopy observations. A few pitting corrosion at 20 wt.% moisture, followed by more degradation at 50 wt.% have been revealed. However, when the moisture amount exceeded 50 wt.%, the surface became entirely covered by a corrosion product. XRD analysis revealed the dominance of FeOOH and Fe3O4 phases on steel surface for a moisture content of 50 wt.%.

  9. Characterization of Mechanical Properties and Residual Stress in API 5L X80 Steel Welded Joints

    Science.gov (United States)

    de Sousa Lins, Amilton; de Souza, Luís Felipe Guimarães; Fonseca, Maria Cindra

    2018-01-01

    The use of high-strength and low-alloy steels, high design factors and increasingly stringent safety requirements have increased the operating pressure levels and, consequently, the need for further studies to avoid and prevent premature pipe failure. To evaluate the possibility of improving productivity in manual arc welding of this type of steel, this work characterizes the mechanical properties and residual stresses in API 5L X80 steel welded joints using the SMAW and FCAW processes. The residual stresses were analyzed using x-ray diffraction with the sin2 ψ method at the top and root of the welded joints in the longitudinal and transverse directions of the weld bead. The mechanical properties of the welded joints by both processes were characterized in terms of tensile strength, impact toughness and Vickers microhardness in the welded and shot peening conditions. A predominantly compressive residual stress was found, and shot peening increased the tensile strength and impact toughness in both welded joints.

  10. Twin-Wire Pulsed Tandem Gas Metal Arc Welding of API X80 Steel Linepipe

    Directory of Open Access Journals (Sweden)

    Wenhao Wu

    2018-01-01

    Full Text Available Twin-Wire Pulsed Tandem Gas Metal Arc Welding process with high welding production efficiency was used to join the girth weld seam of API X80 steel linepipe of 18.4 mm wall thickness and 1422 mm diameter. The macrostructure, microstructure, hardness, and electrochemical corrosion behavior of welded joints were studied. Effects of temperature and Cl− concentration on the corrosion behavior of base metal and weld metal were investigated. Results show that the welded joint has good morphology, mechanical properties, and corrosion resistance. The corrosion resistance of both the base metal and the weld metal decreases with increasing temperature or Cl− concentration. In the solution with high Cl− concentration, the base metal and weld metal are more susceptible to pitting. The corrosion resistance of the weld metal is slightly lower than that of the base metal.

  11. Effect of Microstructure on HIC Susceptibility of API X70MS Linepipe Steel

    Energy Technology Data Exchange (ETDEWEB)

    Sung, Joon-Ho; Sim, Ho-Seop; Park, Byung-Gyu [Dongkuk Steel R and D Center, Pohang (Korea, Republic of); Cho, Kyung-Mox [Pusan National University, Busan (Korea, Republic of)

    2017-06-15

    The resistance of hydrogen induced cracking (HIC) was investigated with different microstructures of API X70MS steel. Ferrite/acicular ferrite (F/AF), deformed ferrite/acicular ferrite, ferrite/bainite (F/B) and single acicular ferrite (AF) were obtained by thermo-mechanical controlled process (TMCP) with changing rolling and cooling conditions. HIC resistance was found to be affected by the type as well as morphology of the microstructure, and thus the behavior of crack initiation and propagation could be analyzed. It was found that single AF and deformed F/AF with uniformly distributed dislocation reduced HIC initiation. Banded microstructure with a hardness value below 250 HV, such as AF, showed good HIC propagation resistance due to high toughness. AF generally exhibited excellent crack initiation and propagation resistance, namely the best HIC susceptibility performance. AF might redeem the HIC resistance for the banded microstructure also.

  12. Study of sulphate-reducing bacteria corrosion in the weld joint for API X-70 steel

    Energy Technology Data Exchange (ETDEWEB)

    Flores, J. E.; Patino-Carachure, C.; Alfonso, I.; Rodriguez, J. A.; Rosas, G.

    2012-11-01

    The corrosion behavior originated by sulfate-reducing bacteria (SRB) was studied in two regions of welded API X-70 steel pipeline. The studies were focused on base material (BM) and heat affected zone (HAZ), from the internal region of the pipe. SRB were extracted from oil and grown in a Postgate medium. Corrosion was evaluated at 60 degree centigrade for times between 5 and 64 days. Potentiodynamic polarization curves, obtained by electrochemical techniques, indicated surface activation at short times. Structural and morphological characterizations were carried out by scanning electron microscopy (SEM) and optical microscopy (OM). H{sub 2}S concentration and pH were also measured. Results showed an important increase in the corrosion damage up to 20 days, influenced by the SRB activity, which lead to a maximum of H{sub 2}S (pH minimum). It was found a localized corrosion attack in the HAZ in a higher quantity compared to BM; and the formation of a thin film on the steel surface, originated by corrosion products and bacterial activity. (Author) 15 refs.

  13. Corrosion study of API 5L x-series pipeline steels in 3.5% NaCl solution under varying conditions

    International Nuclear Information System (INIS)

    Shahid, M.; Qureshi, M.I.; Farooq, M.U.; Khan, M.I.

    2003-01-01

    Pipelines provide convenient and efficient means for mass transportation of variety of fluids, such as oil and gas, over varying distances. In the last two decades or so, pipeline designers focused mainly on the usage of larger sizes and higher operating pressures for achieving higher transportation efficiency. This has been accomplished through the provision of steels with progressive increase in yield strength coupled with good weldability and sufficient toughness to restrict crack propagation. In addition to higher strength and toughness, developing pipeline technologies have required improved resistance to corrosion, which has been tried with specific alloy additions and special control over non-metallic inclusions. Corrosion investigations were carried out on various grades of pipeline steels (API 5L X-46, X-52, X-56, X-60 and X- 70) under varying environmental conditions. This paper describes the results pertaining to corrosion behavior of the steels in 3.5% NaCl solutions in stagnant, turbulent and deaerated conditions. It was found that all grades corrode in this solution and their corrosion potentials and corrosion currents are in close vicinity of each other. Turbulent solutions, however, have shown an increase in corrosion rates whereas deaeration has revealed a relative decrease in aggressivity of the electrolyte. (author)

  14. Semisolid forming of S48C steel grade

    Science.gov (United States)

    Plata, Gorka; Lozares, Jokin; Azpilgain, Zigor; Hurtado, Iñaki; Loizaga, Iñigo; Idoyaga, Zuriñe

    2017-10-01

    Steel production and component manufacturing industries have to face the challenge of globalization, trying to overcome the economic pressure to remain competitive. Moreover, the lightweighting trend of the latter years implies an even higher challenge to maintain the steel use. Therefore, advanced manufacturing processes will be the cornerstone. In this field, Semisolid forming (SSF) has demonstrated the capability of obtaining complex geometries and saving raw material and energy. Despite it is complicated the SSF of sound components, in Mondragon Unibertsitatea it has been successfully demonstrated the capability of producing strong enough automotive components with 42CrMo4 steel grade. In this work, we demonstrate the capability of SSF S48C steel grade with great mechanical properties.

  15. Microbial Corrosion of API 5L X-70 Carbon Steel by ATCC 7757 and Consortium of Sulfate-Reducing Bacteria

    OpenAIRE

    Abdullah, Arman; Yahaya, Nordin; Md Noor, Norhazilan; Mohd Rasol, Rosilawati

    2014-01-01

    Various cases of accidents involving microbiology influenced corrosion (MIC) were reported by the oil and gas industry. Sulfate reducing bacteria (SRB) have always been linked to MIC mechanisms as one of the major causes of localized corrosion problems. In this study, SRB colonies were isolated from the soil in suspected areas near the natural gas transmission pipeline in Malaysia. The effects of ATCC 7757 and consortium of isolated SRB upon corrosion on API 5L X-70 carbon steel coupon were i...

  16. Corrosive effect of oil's accompanying water polluted with H2S over steel (API 5L X-52)

    International Nuclear Information System (INIS)

    Cueli Corugedo, Alexander; Adames Montero, Yosmari; Rivera Beltran, Yischy; Davis Harriet, Juan

    2013-01-01

    The corrosion from the steel to the carbon in the sale oil pipage conduction, is a serious problem, due to the material and economical looses they cause, damaging even in some cases the productive field. The purpose of this study is to determine the aggressiveness of the oil's water layer, polluted with H 2 S ( g) , over the steel of pipelines' construction (API 5L X-52), taking into account the temperature variations which take place during the transportation of the oil, using the electrochemical techniques of polarisation resistance (LPR) and electrochemical noise. It is pretended to determine the velocity of steel corrosion in the oil's water layer polluted with H 2 S through electrochemical techniques. It was shown that the temperature increases and the concentration of H 2 S to 500 ppm in the oil's accompanying water emphasizes the corrosion phenomenon experienced by the steel (9, 188 0 mm/year to 70℃).The results of the electrochemical noise spectrums and the values of the localisation ?s index calculated, shown the presence of corrosion on the steel surface (API 5L X-52).This result was complemented through optic Microscopy which permits to corroborate the poor adherence of the sulphur layers deposited on the metal that increase the appearance of events found with the temperature increase and the concentration of H 2 S in the environment studied

  17. Fatigue crack growth rate of API X70 steel pipelines under spectrum loading

    International Nuclear Information System (INIS)

    Beden, S.M.; Abdullah, S.; Ariffin, A.K.

    2012-01-01

    Pipelines offer the most efficient way to transport bulk quantities of gas and oil, either from points of production to storage locations or from storage locations to distributed points of end use. As one of the main materials of west–east gas transmission pipes, X70 pipelines usually serve under variable amplitude loading (VAL). Base on the importance of in-service API X70 pipelines, it is important for the safe operation of this system to know its behaviour under VAL. This paper focuses on the ability of using the NASGRO model to predict the fatigue crack growth (FCG), based on investigation with the modified Wheeler model and experimental data. The results show that the NASGRO model give a fatigue life near by to that published in literatures and also showed the FCG rate response of X70 pipeline steels when exposed to VAL with different overload values. Extra modification to the NASGRO model may lead to better representing of FCG rate. Highlights: ► The assessment of fatigue crack propagation under different load histories are proposed and presented in this paper. ► Due to lack of knowledge in the related area, as yet no universal model exists. ► The output was based on both simulation and experiments. The simulation part was carried out based on the NASGRO model. ► This work focus on fatigue crack growth (FCG) and fatigue life based on the comparison with the previous work.

  18. Numerical evaluation of multipass welding temperature field in API 5L X80 steel welded joints

    Directory of Open Access Journals (Sweden)

    J Nóbrega

    2016-10-01

    Full Text Available Many are the metallurgical changes suffered by materials when subjected to welding thermal cycle, promoting a considerable influence on the welded structures thermo mechanical properties. In project phase, one alternative for evaluating the welding cycle variable, would be the employment of computational methods through simulation. So, this paper presents an evaluation of the temperature field in a multipass welding of API 5L X80 steel used for oil and gas transportation, using the ABAQUS ® software, based on Finite Elements Method (FEM. During the simulation complex phenomena are considerable including: Variation in physical and mechanical properties of materials as a function of temperature, welding speed and the different mechanisms of heat exchange with the environment (convection and radiation were used. These considerations allow a more robust mathematical modeling for the welding process. An analytical heat source proposed by Goldak, to model the heat input in order to characterize the multipass welding through the GTAW (Gas Tungsten Arc Welding process on root and the SMAW (Shielded Metal Arc Welding process for the filling passes were used. So, it was possible to evaluate the effect of each welding pass on the welded joint temperature field, through the temperature peaks and cooling rates values during the welding process.

  19. Heat treatments in a conventional steel to reproduce the microstructure of a nuclear grade steel

    International Nuclear Information System (INIS)

    Rosalio G, M.

    2014-01-01

    The ferritic steels used in the manufacture of pressurized vessels of Boiling Water Reactors (BWR) suffer degradation in their mechanical properties due to damage caused by the neutron fluxes of high energy bigger to a Mega electron volt (E> 1 MeV) generated in the reactor core. The materials with which the pressurized vessels of nuclear reactors cooled by light water are built correspond to low alloy ferritic steels. The effect of neutron irradiation on these steels is manifested as an increase in hardness, mechanical strength, with the consequent decrease in ductility, fracture toughness and an increase in temperature of ductile-brittle transition. The life of a BWR is 40 years, its design must be considered sufficient margin of safety because pressure forces experienced during operation, maintenance and testing of postulated accident conditions. It is necessary that under these conditions the vessel to behave ductile and likely to propagate a fracture is minimized. The vessels of light water nuclear reactors have a bainite microstructure. Specifically, the reactor vessels of the nuclear power plant of Laguna Verde (Veracruz, Mexico) are made of a steel Astm A-533, Grade B Class 1. At present they are carrying out some welding tests for the construction of a model of a BWR, however, to use nuclear grade steel such as Astm A-533 to carry out some of the welding tests, is very expensive; perform these in a conventional material provides basic information. Although the microstructure present in the conventional material does not correspond exactly to the degree of nuclear material, it can take of reference. Therefore, it is proposed to conduct a pilot study to establish the thermal treatment that reproduces the microstructure of nuclear grade steel, in conventional steel. The resulting properties of the conventional steel samples will be compared to a JRQ steel, that is a steel Astm A-533, Grade B Class 1, provided by IAEA. (Author)

  20. Hydrogen sulfide corrosion of weld regions in API X52 steel; Corrosion por acido sulfhidrico de las regiones de soldadura en acero API X52

    Energy Technology Data Exchange (ETDEWEB)

    Arenas-Martinez, L.F [Universidad Autonoma de Coahuila, Coahuila (Mexico)]. E-mail: fernando.arenas@uadec.edu.mx; Garcia-Cerecero, G. [Corporacion Mexicana de Investigacion en Materiales S.A. de C.V., Saltillo, Coahuila (Mexico)

    2012-10-15

    The corrosion behavior of gas metal arc welding (GMAW) regions has been studied using potentiodynamic polarization and polarization resistance (LPR) techniques. Experiments were conducted in hydrogen sulfide (H{sub 2}S)-containing brine and in H{sub 2}S-free brine. Welds were made on API 5L X52 steel. Due to differences in their microstructure, chemical composition and residual stress level, weld regions exhibited different responses under H{sub 2}S corrosion. Base metal exhibited the highest corrosion rate (CR) and the most cathodic corrosion potential. [Spanish] Se estudio el comportamiento ante la corrosion de las regiones de soldadura de un cordon realizado por arco metalico con gas (GMAW) sobre un acero grado API X52 mediante las tecnicas de polarizacion potencio dinamica y resistencia a la polarizacion (LPR). Los experimentos se realizaron utilizando salmuera con 300 ppm de acido sulfhidrico (H{sub 2}S) y salmuera libre de H{sub 2}S como electrolitos. Debido a las diferencias en su microestructura, composicion quimica y el nivel de esfuerzos residuales, las regiones de soldadura mostraron diferentes respuestas a la corrosion por H{sub 2}S. El metal base exhibio la velocidad de corrosion (VC) mas alta y el potencial de corrosion mas catodico.

  1. 2-Butyne-1,4-diol as a novel corrosion inhibitor for API X65 steel pipeline in carbonate/bicarbonate solution

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghi Meresht, E. [Materials Engineering Department, Faculty of Engineering, Tarbiat Modares University, 1411713114, Tehran (Iran, Islamic Republic of); Shahrabi Farahani, T., E-mail: tshahrabi34@modares.ac.ir [Materials Engineering Department, Faculty of Engineering, Tarbiat Modares University, 1411713114, Tehran (Iran, Islamic Republic of); Neshati, J. [Research Institute of Petroleum Industry, RIPI, 1485733111, Tehran (Iran, Islamic Republic of)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer Corrosion of API 5L X65 is effectively reduced by the addition of the inhibitor. Black-Right-Pointing-Pointer The techniques include weight loss, potentiodynamic polarization, EIS and AFM. Black-Right-Pointing-Pointer 2-Butyne-1,4-diol acts as a mixed-type inhibitor. Black-Right-Pointing-Pointer The adsorption of 2-butyne-1,4-diol obeys Langmuir adsorption isotherm. - Abstract: The inhibition effects of 2-butyne-1,4-diol on the corrosion susceptibility of grade API 5L X65 steel pipeline in 2 M Na{sub 2}CO{sub 3}/1 M NaHCO{sub 3} solution were studied by electrochemical techniques and weight loss measurements. The results indicated that this inhibitor was a mixed-type inhibitor, with a maximum percentage inhibition efficiency of approximately 92% in the presence of 5 mM inhibitor. Atomic force microscopy revealed that a protective film was formed on the surface of the inhibited sample. The adsorption of the inhibitor was found to conform to the Langmuir isotherm with the standard adsorption free energy of -21.08 kJ mol{sup -1}.

  2. 2-Butyne-1,4-diol as a novel corrosion inhibitor for API X65 steel pipeline in carbonate/bicarbonate solution

    International Nuclear Information System (INIS)

    Sadeghi Meresht, E.; Shahrabi Farahani, T.; Neshati, J.

    2012-01-01

    Highlights: ► Corrosion of API 5L X65 is effectively reduced by the addition of the inhibitor. ► The techniques include weight loss, potentiodynamic polarization, EIS and AFM. ► 2-Butyne-1,4-diol acts as a mixed-type inhibitor. ► The adsorption of 2-butyne-1,4-diol obeys Langmuir adsorption isotherm. - Abstract: The inhibition effects of 2-butyne-1,4-diol on the corrosion susceptibility of grade API 5L X65 steel pipeline in 2 M Na 2 CO 3 /1 M NaHCO 3 solution were studied by electrochemical techniques and weight loss measurements. The results indicated that this inhibitor was a mixed-type inhibitor, with a maximum percentage inhibition efficiency of approximately 92% in the presence of 5 mM inhibitor. Atomic force microscopy revealed that a protective film was formed on the surface of the inhibited sample. The adsorption of the inhibitor was found to conform to the Langmuir isotherm with the standard adsorption free energy of −21.08 kJ mol −1 .

  3. Comparative Study of API 5L X60 and ASTM 572 Gr50 Steel Exposed to Crude Oil and Seawater

    Directory of Open Access Journals (Sweden)

    Marcy Viviana Chiquillo Márquez

    2018-04-01

    Full Text Available In the petroleum industry, the biphasic conditions in storage and separation tanks allow that the material to remain exposed to two different environments, causing its deterioration. In this article, an evaluation is made of the corrosive behavior and Vickers microhardness (HV of two high strength low alloy (HSLA steels and how their surfaces are characterized. The ASTM 572 Gr50 steel showed a lower corrosion rate in all systems after being immersed for 720 and 1440 hours. Characterizing the surface by means of Scanning Electron Microscopy (SEM showed uniform and localized corrosion for the both steels, and revealed that the ASTM 572 Gr50 steel shows pitting corrosion in crude oil systems. The electrochemical results revealed that the corrosion potential of API X60 steel was more negative; however the ASTM 572 Gr50 steel had a higher current density and a lower polarization resistance when immersed in an oil/seawater mixture. It also observed that, after being immersed in the corrosive fluids, the microstructures of the steels were not modified and variations in their microhardness (HV were minute.

  4. Effect of Different Thermomechanical Processes on the Microstructure, Texture, and Mechanical Properties of API 5L X70 Steel

    Science.gov (United States)

    Masoumi, Mohammad; Echeverri, Edwan Anderson Ariza; Silva, Cleiton Carvalho; Béreš, Miloslav; de Abreu, Hamilton Ferreira Gomes

    2018-03-01

    A commercial API 5L X70 steel plate was subjected to different thermomechanical processes to propose a novel thermomechanical rolling path to achieve improved mechanical properties. Scanning electron microscopy, electron backscatter diffraction, and x-ray texture analysis were employed for microstructural characterization. The results showed that strain-free recrystallized {001} ferrite grains that developed at higher rolling temperature could not meet the American Petroleum Institute (API) requirements. Also, refined and work-hardened grains that have formed in the intercritical region with high stored energy do not provide suitable tensile properties. However, fine martensite-austenite constituents dispersed in ferrite matrix with grains having predominantly {111} and {110} orientations parallel to the normal direction that developed under isothermal rolling at 850 °C provided an outstanding combination of tensile strength and ductility.

  5. Study of sulphate-reducing bacteria corrosion in the weld joint for API X-70 steel

    Directory of Open Access Journals (Sweden)

    Flores, J. E.

    2012-10-01

    Full Text Available The corrosion behavior originated by sulfate-reducing bacteria (SRB was studied in two regions of welded API X-70 steel pipeline. The studies were focused on base material (BM and heat affected zone (HAZ, from the internal region of the pipe. SRB were extracted from oil and grown in a Postgate medium. Corrosion was evaluated at 60 °C for times between 5 and 64 days. Potentiodynamic polarization curves, obtained by electrochemical techniques, indicated surface activation at short times. Structural and morphological characterizations were carried out by scanning electron microscopy (SEM and optical microscopy (OM. H2S concentration and pH were also measured. Results showed an important increase in the corrosion damage up to 20 days, influenced by the SRB activity, which lead to a maximum of H2S (pH minimum. It was found a localized corrosion attack in the HAZ in a higher quantity compared to BM; and the formation of a thin film on the steel surface, originated by corrosion products and bacterial activity.

    El comportamiento ante la corrosión, originada por bacterias sulfato-reductoras (SRB, fue estudiado en dos regiones de un tubo de acero soldado API X-70. Los estudios se enfocaron en el material base (BM y la zona afectada térmicamente (HAZ, en la parte interna del tubo. Las SRB fueron extraídas del petróleo y cultivadas en un medio Postgate. El comportamiento a la corrosión fue evaluado a una temperatura de 60 °C, por periodos comprendidos entre 5 y 64 días. El análisis de las curvas de polarización potenciodinámicas, obtenidas por técnicas electroquímicas, indicó la activación de la superficie para tiempos cortos. La superficie fue caracterizada estructural y morfológicamente mediante microscopia electrónica de barrido (SEM, así como mediante microscopía óptica (OM. La concentración de H2S y el pH también fueron medidos. Los resultados mostraron un aumento importante de la corrosi

  6. Mechanical properties of API X80 steel pipe joints welded by Flux Core Arc Weld Process; Propriedades mecanicas de juntas de tubos de aco API X80 soldadas com arame tubulares

    Energy Technology Data Exchange (ETDEWEB)

    Ordonez, Robert E. Cooper; Silva, Jose Hilton F.; Trevisan, Roseana E. [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Mecanica. Dept. de Engenharia de Fabricacao

    2003-07-01

    Flux Core Arc Welding processes (FCAW) are beginning to be applied in pipeline welds, however, very limited experimental data regarding mechanical properties of pipeline weld joints with these processes are available in the literature. In this paper, the effects of preheat temperature and type of FCAW on mechanical properties (microhardness and tensile strength) of API X80 weld joint steel are presented. FCAW processes with gas protection and self-shielded were used. Multipasses welding were applied in 30'' diameter and 0,625'' thickness tubes. Influence factors were: FCAW type and preheat temperature. Acceptance criteria of welded joints were evaluated by API 1104 standard for tensile strength test and ASTM E384-99 for microhardness test. The results obtained showed that FCAW type and preheat temperature have no influence on mechanical properties of API X80 joint steel. (author)

  7. Effect of Pipe Flattening in API X65 Linepipe Steels Having Bainite vs. Ferrite/Pearlite Microstructures

    Directory of Open Access Journals (Sweden)

    Singon Kang

    2018-05-01

    Full Text Available The influence of microstructure on pipe flattening response was assessed using two different commercially produced U-ing, O-ing, and expansion (UOE pipes from API X65 steels having either a bainitic microstructure (steel B or a ferrite/pearlite microstructure (steel FP. A four-point bending apparatus and distinctive procedure were used to minimize strain localization during flattening. The flattened specimens were sectioned at different positions through the thickness, and tensile tested in both the longitudinal (LD and transverse directions (TD to assess the through-thickness variation in properties. Yield strength (YS distributions in the LD show V-shaped profiles through thickness in both steels, whereas the YS in the TD nearest the outside diameter (OD surface is reduced. These variations in YS are due to the Bauschinger effect associated with the compressive flattening pre-strain. The uniform elongation (UE of steel FP is almost independent of specimen position through the thickness, but for steel B there is a substantial reduction of the UE at both the inside and outside diameter positions and this reduction is greater in the LD. This work confirms that flattened pipe mechanical properties exhibit an important dependence on their microstructure type and it is postulated that the flattening procedure also influences the mechanical properties.

  8. Corrosion resistance of ERW (Electric Resistance Welded) seam welds as compared to metal base in API 5L steel pipes

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Velasquez, Jorge L.; Godinez Salcedo, Jesus G.; Lopez Fajardo, Pedro [Instituto Politecnico Nacional (IPN), Mexico D.F. (Mexico). Escuela Superior de Ingenieria Quimica e Industrias Extractivas (ESIQIE). Dept. de Ingenieria Metalurgica

    2009-07-01

    The corrosion resistance of ERW seam welds and the base metal in API 5L X70 steel pipes was evaluated by Tafel tests. The procedure was according to ASTM G3 standard. The study was completed with metallographic and chemical characterization of the tested zones, that is, the welded zone and the base metal away of the weld. All tests were made on the internal surface of the pipe in order to assess the internal corrosion of an in-service pipeline made of the API 5L X70 steel. The test solution was acid brine prepared according to NACE Publications 1D182 and 1D196. The results showed that the ERW seam weld corrodes as much as three times faster than the base material. This behavior is attributed to a more heterogeneous microstructure with higher internal energy in the ERW seam weld zone, as compared to the base metal, which is basically a ferrite pearlite microstructure in a normalized condition. This result also indicates that pipeline segments made of ERW steel pipe where the seam weld is located near or at the bottom of the pipe are prone to a highly localized attack that may form channels of metal loss if there is water accumulation at the bottom of the pipeline. (author)

  9. Evaluation of the creep cavitation behavior in Grade 91 steels

    International Nuclear Information System (INIS)

    Siefert, J.A.; Parker, J.D.

    2016-01-01

    Even in properly processed Grade 91 steel, the long term performance and creep rupture strength of base metal is below that predicted from a simple extrapolation of short term data. One of the mechanisms responsible for this reduction in strength is the development of creep voids. Importantly, nucleation, growth and inter linkage of voids under long term creep conditions also results in a significant loss of creep ductility. Thus, elongations to rupture of around 5% in 100,000 h are now considered normal for creep tests on many tempered martensitic steels. Similarly, creep damage development in the heat affected zones of welds results in low ductility cracking at times below the minimum expected life of base metal. In all cases, the relatively brittle behavior is directly a consequence of creep void development. Indeed, the results of component root cause analysis have shown that crack development in Grade 91 steel in-service components is also a result of the formation of creep voids. The present paper examines background on the nucleation and development of creep voids in 9%Cr type martensitic steels, presents information regarding methods which allow proper characterization of the creep voids and discusses factors affecting creep fracture behavior in tempered martensitic steels. It is apparent that the maximum zone of cavitation observed in Grade 91 steel welds occurred in a region in the heat affected zone which is ∼750 μm in width. This region corresponds to the band where the peak temperature during welding is in the range of ∼1150–920 °C.The cavity density in this band was over about 700 voids/mm"2 at an estimated creep life fraction of ∼99%. - Highlights: • The present paper examines background on the nucleation and development of creep voids in 9%Cr type martensitic steels. • Information regarding methods which allow proper characterization of the creep voids is also presented. • Factors affecting creep fracture behavior in tempered

  10. Influence of the maximum applied magnetic field on the angular dependence of Magnetic Barkhausen Noise in API5L steels

    Energy Technology Data Exchange (ETDEWEB)

    Martínez-Ortiz, P. [Laboratorio de Evaluación No Destructiva Electromagnética (LENDE), ESIME-SEPI, Edif. Z-4, Instituto Politécnico Nacional, Zacatenco, México D.F. (Mexico); Pérez-Benítez, J.A., E-mail: japerezb@ipn.mx [Laboratorio de Evaluación No Destructiva Electromagnética (LENDE), ESIME-SEPI, Edif. Z-4, Instituto Politécnico Nacional, Zacatenco, México D.F. (Mexico); Espina-Hernández, J.H. [Laboratorio de Evaluación No Destructiva Electromagnética (LENDE), ESIME-SEPI, Edif. Z-4, Instituto Politécnico Nacional, Zacatenco, México D.F. (Mexico); Caleyo, F. [Departamento de Ingeniería Metalúrgica, ESIQIE, UPALM Edif. 7, Instituto Politécnico Nacional, Zacatenco, C.P. 07738 México D.F. (Mexico); Mehboob, N.; Grössinger, R. [Institute of Solid State Physics, Vienna University of Technology, Vienna A-1040 (Austria); Hallen, J.M. [Departamento de Ingeniería Metalúrgica, ESIQIE, UPALM Edif. 7, Instituto Politécnico Nacional, Zacatenco, C.P. 07738 México D.F. (Mexico)

    2016-03-01

    This work studies the influence of the maximum applied magnetic field on the angular dependence of the energy of the Magnetic Barkhausen Noise signal in three different API5L pipeline steels. The results show that the shape of the angular dependence of the Magnetic Barkhausen Noise energy changes with the increase of the amplitude of the applied magnetic field. This phenomenon is a consequence of the presence of unlike magnetization processes at different magnitudes of the applied magnetic field. The outcomes reveal the importance of controlling the value of the maximum applied field as parameter for the improvement of the MBN angular dependence measurements. - Highlights: • Study the angular dependence of MBN with applied field in three pipeline steels. • Reveals the change of this angular dependence with the increase applied field. • Explains this dependence based on the domain wall dynamics theory.

  11. Influence of the maximum applied magnetic field on the angular dependence of Magnetic Barkhausen Noise in API5L steels

    International Nuclear Information System (INIS)

    Martínez-Ortiz, P.; Pérez-Benítez, J.A.; Espina-Hernández, J.H.; Caleyo, F.; Mehboob, N.; Grössinger, R.; Hallen, J.M.

    2016-01-01

    This work studies the influence of the maximum applied magnetic field on the angular dependence of the energy of the Magnetic Barkhausen Noise signal in three different API5L pipeline steels. The results show that the shape of the angular dependence of the Magnetic Barkhausen Noise energy changes with the increase of the amplitude of the applied magnetic field. This phenomenon is a consequence of the presence of unlike magnetization processes at different magnitudes of the applied magnetic field. The outcomes reveal the importance of controlling the value of the maximum applied field as parameter for the improvement of the MBN angular dependence measurements. - Highlights: • Study the angular dependence of MBN with applied field in three pipeline steels. • Reveals the change of this angular dependence with the increase applied field. • Explains this dependence based on the domain wall dynamics theory.

  12. The influence of surface roughness on the hydrogen permeation of type API 5L-X52 steel; Influencia del acabado superficial en la permeacion de hidrogeno del acero API 5L-X52 steel

    Energy Technology Data Exchange (ETDEWEB)

    Requiz, R; Vera, N; Camero, S

    2004-07-01

    The influence of surface reoughness on the corrosion and hydrogen permeation behaviour was evaluated on a type API 5L-52 steel in dearated 0.1M NaSO{sub 4} at pH=2. Potentiodynamic polarization curves were emplyed to determine the electrochemical behaviour of the steel, while the Devanathan-Stachurski technique was used to estimate the hydrogen permeation rate. Additionally, the surface roughness profiles were obtained in order to correlate the changes in the hydrogen perkeation rate with different metal surface finishings. The obtained results clearly demonstrate that when the roughness parameters have larger values, the cathodic current of hydrogen evolution increases while the hydrogen entry rate decreases. This effect can be attributed to the microstructural defects induced at the steel surface, such as dislocations, which increase the catalytic activity of the atomic hydrogen favouring its recombination. Also, these defects could allow the atomic hydrogen to remain adsorbed on the steel surface. Both effects could hinder the hydrogen diffusion into the metal since the possibility for this atom of becoming absorbed has been reduced. (Author) 16 refs.

  13. The influence of surface roughness on the hydrogen permeation of type API 5L-X52 steel

    International Nuclear Information System (INIS)

    Requiz, R.; Vera, N.; Camero, S.

    2004-01-01

    The influence of surface roughness on the corrosion and hydrogen permeation behaviour was evaluated on a type API 5L-52 steel in dearated 0.1M NaSO 4 at pH=2. Potentiodynamic polarization curves were employed to determine the electrochemical behaviour of the steel, while the Devanathan-Stachurski technique was used to estimate the hydrogen permeation rate. Additionally, the surface roughness profiles were obtained in order to correlate the changes in the hydrogen perkeation rate with different metal surface finishings. The obtained results clearly demonstrate that when the roughness parameters have larger values, the cathodic current of hydrogen evolution increases while the hydrogen entry rate decreases. This effect can be attributed to the microstructural defects induced at the steel surface, such as dislocations, which increase the catalytic activity of the atomic hydrogen favouring its recombination. Also, these defects could allow the atomic hydrogen to remain adsorbed on the steel surface. Both effects could hinder the hydrogen diffusion into the metal since the possibility for this atom of becoming absorbed has been reduced. (Author) 16 refs

  14. Creep rupture behavior of welded Grade 91 steel

    Energy Technology Data Exchange (ETDEWEB)

    Shrestha, Triratna [Department of Chemical and Materials Engineering, University of Idaho, Moscow, ID 83844 (United States); Basirat, Mehdi [Department of Mechanical Engineering, University of Idaho, Moscow, ID 83844 (United States); Alsagabi, Sultan; Sittiho, Anumat [Department of Chemical and Materials Engineering, University of Idaho, Moscow, ID 83844 (United States); Charit, Indrajit, E-mail: icharit@uidaho.edu [Department of Chemical and Materials Engineering, University of Idaho, Moscow, ID 83844 (United States); Potirniche, Gabriel P. [Department of Mechanical Engineering, University of Idaho, Moscow, ID 83844 (United States)

    2016-07-04

    Creep rupture behavior of fusion welded Grade 91 steel was studied in the temperature range of 600 – 700 °C and at stresses of 50–200 MPa. The creep data were analyzed in terms of the Monkman-Grant relation and Larson-Miller parameter. The creep damage tolerance factor was used to identify the origin of creep damage. The creep damage was identified as the void growth in combination with microstructural degradation. The fracture surface morphology of the ruptured specimens was studied by scanning electron microscopy and deformed microstructure examined by transmission electron microscopy, to further elucidate the rupture mechanisms.

  15. Effect of Ethanol Chemistry on SCC of Carbon Steel

    Science.gov (United States)

    2011-02-22

    Pipeline companies have a keen interest in assessing the feasibility of transporting fuel grade ethanol (FGE) and ethanol blends in existing pipelines. Previous field experience and laboratory research, funded by PRCI and API, has shown that steel ca...

  16. Effect of quenching and tempering process on sulfide stress cracking susceptibility in API-5CT-C110 casing steel

    Energy Technology Data Exchange (ETDEWEB)

    Liu, M.; Wang, C.H.; Dai, Y.C.; Li, X.; Cao, G.H. [State Key Laboratory of Advanced Special Steel & Shanghai Key Laboratory of Advanced Ferrometallurgy & School of Materials Science and Engineering, Shanghai University, 149 Yanchang Road, Shanghai 200072 (China); Russell, A.M. [Division of Materials Science and Engineering, Ames Laboratory of the U.S.D.O.E., and Department of Materials Science and Engineering, Iowa State University, Ames, IA 50011-2300 (United States); Liu, Y.H.; Dong, X.M. [Tube & Pipe Department, Baosteel Research Institute, Baoshan Iron & Steel Co., Ltd, Shanghai 201900 (China); Zhang, Z.H., E-mail: zhzhang@baosteel.com [Tube & Pipe Department, Baosteel Research Institute, Baoshan Iron & Steel Co., Ltd, Shanghai 201900 (China)

    2017-03-14

    Three quenching and tempering processes performed on API-5CT-C110 casing steel produced tempered martensite structures and similar mechanical properties but distinct sulfide stress cracking (SSC) behavior as evaluated by Double Cantilever Beam (DCB) testing. An as-quenched specimen tempered at 690 °C for two hours showed superior SSC behavior compared to another specimen tempered at 715 °C for one hour. The latter contained a larger fraction of low-angle boundaries (LABs) and higher values of kernel average misorientation (KAM) than those in the former. Moreover, one more quenching and tempering on the former specimen would produce better SSC resistance with a decrease in the fraction of LABs and the values of KAM. Since dislocations trap hydrogen more strongly than grain boundaries, the specimen with higher KAM values, as well as higher dislocation density, would trap more hydrogen atoms and lead to greater SSC.

  17. Comparison of angular dependence of magnetic Barkhausen noise of hysteresis and initial magnetization curve in API5L steel

    Science.gov (United States)

    Chávez-Gonzalez, A. F.; Martínez-Ortiz, P.; Pérez-Benítez, J. A.; Espina-Hernández, J. H.; Caleyo, F.

    2018-01-01

    This work analyzes the differences between the magnetic Barkhausen noise corresponding to the initial magnetization curve and Barkhausen noise corresponding to one branch of the hysteresis loop in API-5L steel. The outcomes show that the Barkhausen noise signal corresponding to the initial magnetization curve and that corresponding to the hysteresis are significantly different. This difference is due to the presence of different processes of the domain wall dynamics in both phenomena. To study the processes present in magnetization dynamics for an applied field of H > 0, research into the angular dependence of a Barkhausen signal using applied field bands has revealed that a Barkhausen signal corresponding to the initial magnetization curve is more suitable than a Barkhausen signal corresponding to the hysteresis loop.

  18. Tribological performances of new steel grades for hot stamping tools

    Science.gov (United States)

    Medea, F.; Venturato, G.; Ghiotti, A.; Bruschi, S.

    2017-09-01

    In the last years, the use of High Strength Steels (HSS) as structural parts in car body-in-white manufacturing has rapidly increased thanks to their favourable strength-to-weight ratio and stiffness, which allow a reduction of the fuel consumption to accommodate the new restricted regulations for CO2 emissions control. The survey of the technical and scientific literature shows a large interest in the development of different coatings for the blanks from the traditional Al-Si up to new Zn-based coatings and on the analysis of hard PVD, CVD coatings and plasma nitriding applied on the tools. By contrast, fewer investigations have been focused on the development and test of new tools steels grades capable to improve the wear resistance and the thermal properties that are required for the in-die quenching during forming. On this base, the paper deals with the analysis and comparison the tribological performances in terms of wear, friction and heat transfer of new tool steel grades for high-temperature applications, characterized by a higher thermal conductivity than the commonly used tools. Testing equipment, procedures as well as measurements analyses to evaluate the friction coefficient, the wear and heat transfer phenomena are presented. Emphasis is given on the physical simulation techniques that were specifically developed to reproduce the thermal and mechanical cycles on the metal sheets and dies as in the industrial practice. The reference industrial process is the direct hot stamping of the 22MnB5 HSS coated with the common Al-Si coating for automotive applications.

  19. Study of API 5L X70 steel corrosion processes when in contact with some Brazilian soils

    International Nuclear Information System (INIS)

    Jesus, Sergio Luis de

    2007-01-01

    Pipelines, fuel storage tanks and other metallic structures are in permanent contact and exposed to different types of soils, of horizons or layers, or of soil aggressiveness. This interaction may cause expressive damages to the environment and to the planned work. Contamination may occur due to leakage of stored products, splitting during transportation, accidents caused by pipelines without extensive maintenance. The result of these accidents could be, among others, some financial losses. In order to recognize the dynamic interactions between metallic surfaces and the environment it is crucial to have preventive actions and to develop better-applied materials. API steel 5L X70 has been used in structures of low and high pressure with high mechanical strength and corrosion and, even so, it is susceptible to etching corrosion since it is in contact with different environments from mangrove regions to industrial environments. The present case evaluated the role of 5L X70 API steel in contact with different soil horizons representative of the Brazilian soil. This investigation correlated chemical species with solute ions in soil solution, secondary and primary phase minerals besides physical and chemical characteristics as pH, electric conductivity, total dissolved solids, among others, to the results of corrosion resistance and ways of corrosion. The evaluation was carried out using x-ray diffractometry, scanning electron microscopy, total reflection x-ray fluorescence, fuel injection flow besides texture and gravimetric analyses to soil characterization and mineralogy, identification of corrosion products, soil solution analyses, evaluation of tested materials and classification of ways and types of corrosion. This was an attempt to integrate the data to a better understanding of the process involving reagents and products. The results showed that different soil horizons such as different types of analyzed soils produce specific etching in metallic structures

  20. Application of ANFIS for analytical modeling of tensile strength of functionally graded steels

    Directory of Open Access Journals (Sweden)

    Ali Nazari

    2012-06-01

    Full Text Available In the present study, the tensile strength of ferritic and austenitic functionally graded steels produced by electroslag remelting has been modeled. To produce functionally graded steels, two slices of plain carbon steel and austenitic stainless steels were spot welded and used as electroslag remelting electrode. Functionally graded steel containing graded layers of ferrite and austenite may be fabricated via diffusion of alloying elements during remelting stage. Vickers microhardness profile of the specimen has been obtained experimentally and modeled with adaptive network-based fuzzy inference systems (ANFIS. To build the model for graded ferritic and austenitic steels, training, testing and validation using respectively 174 and 120 experimental data were conducted. According to the input parameters, in the ANFIS model, the Vickers microhardness of each layer was predicted. A good fit equation which correlates the Vickers microhardness of each layer to its corresponding chemical composition was achieved by the optimized network for both ferritic and austenitic graded steels. Afterwards; the Vickers microhardness of each layer in functionally graded steels was related to the yield stress of the corresponding layer and by assuming Holloman relation for stress-strain curve of each layer, they were acquired. Finally, by applying the rule of mixtures, tensile strength of functionally graded steels configuration was found through a numerical method. The obtained results from the proposed model are in good agreement with those acquired from the experiments.

  1. Hall–Petch and dislocation strengthening in graded nanostructured steel

    DEFF Research Database (Denmark)

    Zhang, Xiaodan; Hansen, Niels; Gao, Yukui

    2012-01-01

    The structure and strength of low carbon steel samples have been analyzed after plastic deformation by shot-peening and cold-rolling. The fine scale surface microstructure caused by shot-peening extends to ∼50 μm below the surface. The structure is graded and subdivided by dislocation boundaries...... and high angle boundaries showing a clear resemblance to the lamellar structure, which evolves during conventional rolling of bulk metallic materials from medium to high strain. As the surface is approached, the boundary spacing decreases to ∼50 nm at the surface. In parallel, the misorientation angle...... is the average spacing between the low and high angle boundaries which subdivide the microstructure, σ0 is the friction stress and k2 is a number which is expressed in terms of structural parameters which have been determined by electron backscattered diffraction. It is found that calculated k2 values...

  2. Ductility in hot isostatically pressed 250-grade maraging steel

    International Nuclear Information System (INIS)

    German, R.M.; Smugeresky, J.E.

    1978-01-01

    Prealloyed 250-grade maraging steel powder produced by the rotating electrode process was fully consolidated by hot isostatic pressing (HIP) at 1100 and 1200 0 C. The strength following aging (3 h at 480 0 C) equalled that of wrought material; however, ductility was negligible. This lack of ductility in the powder metallurgy product was traced to titanium segregation which occurred at the powder surface during power production. The formation of a titanium intermetallic at the prior particle boundaries during aging caused failure at low plastic strains. Altered aging treatments successfully broke up the embrittling film and resulted in a significant ductility recovery for the HIP material. Analysis of the fracture process indicates that further ductility gains are possible by reducing the titanium content, refining the particle size, and optimizing the thermal cycles

  3. Stress corrosion cracking of A515 grade 60 carbon steel

    International Nuclear Information System (INIS)

    Moore, E.L.

    1971-01-01

    An investigation was conducted to evaluate the effect of welding method plate thickness, and subsequent stress relief treatment on the stress corrosion cracking propensity of ASTM A515 Grade 60 carbon steel plate exposed to a 5 M NaNO 3 solution at 190 0 F for eight weeks. It was found that all weld coupons receiving no thermal stress relief treatment cracked within eight weeks; all weld coupons given a vibratory stress relief cracked within eight weeks; two of the eight weld coupons stress relieved at 600 0 F for one hour cracked within eight weeks; none of the weld coupons stress relieved at 1100 0 F for one hour cracked within eight weeks; and that cracking was generally more severe in coupons fabricated from 7/8 inch plate by shielded metal arc welding than it was in coupons fabricated by other welding methods. (U.S.)

  4. Hall–Petch and dislocation strengthening in graded nanostructured steel

    International Nuclear Information System (INIS)

    Zhang Xiaodan; Hansen, Niels; Gao Yukui; Huang Xiaoxu

    2012-01-01

    The structure and strength of low carbon steel samples have been analyzed after plastic deformation by shot-peening and cold-rolling. The fine scale surface microstructure caused by shot-peening extends to ∼50 μm below the surface. The structure is graded and subdivided by dislocation boundaries and high angle boundaries showing a clear resemblance to the lamellar structure, which evolves during conventional rolling of bulk metallic materials from medium to high strain. As the surface is approached, the boundary spacing decreases to ∼50 nm at the surface. In parallel, the misorientation angle across boundaries increases to ∼65% of high angle boundaries. The cold-rolled steel shows a low hardening rate at high strain and by assuming additive strength contributions from Hall–Petch and dislocation strengthening, the flow stress has been expressed by the relationship σ-σ 0 =k 2 D av -0.5 , where D av is the average spacing between the low and high angle boundaries which subdivide the microstructure, σ 0 is the friction stress and k 2 is a number which is expressed in terms of structural parameters which have been determined by electron backscattered diffraction. It is found that calculated k 2 values are in accord with an experimental value of 310 MPa μm 0.5 . In the shot-peened steel the increase in D av with increasing distance from the surface is transformed into a stress profile based on the σ - D av relationship established for cold-rolled bulk samples. The calculated stress profile is validated by comparison with the experimental profile based on hardness measurements, and good agreement is found. This result points to a wider application of the suggested method to derive the local flow stress in a deformed microstructure based on a measurement of the local boundary spacing and the stress–structure relationship for the bulk material in the deformed state.

  5. Technological impact in steels degree API 5L X-70 for the manufacture of resistant ducts of 36 inches of diameter to the bitter gas; Impacto tecnologico de aceros grado API 5L X-70 para la fabricacion de ductos de 36 pulgadas de diametro resistentes al gas amargo

    Energy Technology Data Exchange (ETDEWEB)

    Aramburo Perez, G.; Garcia Galan, S.; Perez Campos, R.; Juarez Islas, J.A. [Facultad de Quimica, UNAM, Mexico, D.F. (Mexico)

    2004-03-01

    Several steel plates in the as-hot rolled plus cooled condition were studied, in order to evaluate the impact of the steelmaking route and the controlled thermomechanical processing plus the cooling media. The steelmaking route to produce the slabs involved the use of 100% sponge iron which was feed into an electric arc furnace, vacuum degassed, ladle treated and continuously cast. After soaking, a controlled thermomechanical processing the resulting steel plates cooled in air showed a banded structure, which sometimes presented a central segregation region. The worst plates with a central segregation region showed intermetallic compounds in it. After modifications of the steelmaking route and the controlled thermomechanical/cooling schedule, a steel plate with a ferritic microstructure plus 0.5% in vol of bainite was obtained. This microstructure together with the resulting mechanical properties, fulfilled the API grade 5LX-70 properties, required by the petroleum industry. [Spanish] Se evaluo el impacto del proceso en la fabricacion de planchones de acero grado APIX-70, asimismo, el proceso de deformacion termomecanico controlado, mas enfriamiento de placas. El proceso para producir los planchones involucra el uso de 100% de hierro esponja, el cual es alimentado a un horno electrico, desgasificado al vacio y colado continuamente. Al planchon resultante se le aplica un programa de laminacion en caliente controlado y a las placas resultantes se le aplica un enfriamiento al aire o acelerado. La mayoria de las placas enfriadas al aire mostraron una estructura bandeada, algunas presentaron una region con segregacion central y otras las segregacion central mas la presencia de intermetalicos. Despues de modificar el proceso de fabricacion del acero, su control termomecanico y su programa de enfriamiento, se obtuvo una placa con una microestructura ferrifica mas un 0.5% en volumen de bainita. Esta microestructura junto con el resultado de sus propiedades mecanicas

  6. In-service behavior of creep strength enhanced ferritic steels Grade 91 and Grade 92 – Part 1 parent metal

    International Nuclear Information System (INIS)

    Parker, Jonathan

    2013-01-01

    In creep strength enhanced ferritic steels, such as Grade 91 and Grade 92, control of both composition and heat treatment of the parent steel is necessary to avoid producing components which have creep strength below the minimum expected by applicable ASME and other International Codes. These efforts are required to ensure that the steel develops a homogeneous fully tempered martensitic microstructure, with the appropriate distribution of precipitates and the required dislocation substructure. In-service creep related problems with Grade 91 steel have been reported associated with factors such as incorrect microstructure and heat treatment, welded connections in headers and piping, dissimilar metal welds as well as the manufacture and performance of castings. Difficulties associated with remediation of in-service damage include challenges over detection and removal of damaged material as well as the selection and qualification of appropriate methodologies for repair. Since repeated heat treatment leads to continued tempering, and a potential degradation of properties, specific procedures for performing and then lifing repair welds are a key aspect of Asset Management. This paper presents a summary of in-service experience with Grade 91 steel and outlines approaches for repair welding. Highlights: ► The steel alloy known as Grade 91 is widely used to fabricate critical pressure part components. ► Designers favor Grade 91 because it provides superior elevated temperature strength at substantially lower cost than the austenitic stainless steels. ► Service experience has confirmed that early failures can occur. ► Life management solutions involved attention to detail at Purchase, during design and all stages of fabrication.

  7. Microbial Corrosion of API 5L X-70 Carbon Steel by ATCC 7757 and Consortium of Sulfate-Reducing Bacteria

    Directory of Open Access Journals (Sweden)

    Arman Abdullah

    2014-01-01

    Full Text Available Various cases of accidents involving microbiology influenced corrosion (MIC were reported by the oil and gas industry. Sulfate reducing bacteria (SRB have always been linked to MIC mechanisms as one of the major causes of localized corrosion problems. In this study, SRB colonies were isolated from the soil in suspected areas near the natural gas transmission pipeline in Malaysia. The effects of ATCC 7757 and consortium of isolated SRB upon corrosion on API 5L X-70 carbon steel coupon were investigated using a weight loss method, an open circuit potential method (OCP, and a potentiodynamic polarization curves method in anaerobic conditions. Scanning electron microscopy (SEM and energy dispersive X-ray spectroscopy (EDS were then used to determine the corrosion morphology in verifying the SRB activity and corrosion products formation. Results from the study show that the corrosion rate (CR of weight loss method for the isolated SRB is recorded as 0.2017 mm/yr compared to 0.2530 mm/yr for ATCC 7757. The Tafel plot recorded the corrosion rate of 0.3290 mm/yr for Sg. Ular SRB and 0.2500 mm/yr for Desulfovibrio vulgaris. The results showed that the consortia of isolated SRB were of comparable effects and features with the single ATCC 7757 strain.

  8. Effect of artificial aging on the microstructure of weldment on API 5L X-52 steel pipe

    International Nuclear Information System (INIS)

    Vargas-Arista, B.; Hallen, J.M.; Albiter, A.

    2007-01-01

    The effects of artificial aging on the microstructure in the weldment of an API 5L X-52 steel pipe were studied. Aging was performed at 250 deg. C over a period of 1000 h and values were recorded at every 100 h intervals. Transmission electron microscopy observations showed precipitation strengthening from nearly circular Nb-C containing nanoparticles for the base metal and heat affected zone, and cementite for the weld metal. The largest amount of precipitation in the weldment zone was obtained at 500 h, due to peak-aging, which showed the highest particle density. The weld metal was more susceptible to aging, exhibiting the highest increase in precipitation at 500 h, followed by the heat affected zone. After 500 h, the deterioration in the microstructure was caused by the coarsening of particles due to over-aging. The base metal showed the larger increment in particle size after 900 h of aging accompanied by a bigger decrease in fine particles than in the weld metal

  9. Corrosion rate of API 5L Gr. X60 multipurpose steel pipeline under combined effect of water and crude oil

    Science.gov (United States)

    Miao, Jian; Wang, Qiang

    2016-09-01

    Multipurpose pipeline is often seriously corroded during its service life, and the phenomenon is more prominent once the transportation medium is changed. Electrochemical polarization curves and impedance spectroscopy of the API 5L Gr. X60 steel pipeline's corrosion process in sedimentary water with different ion types and their concentrations have been studied in this work. The results showed that the corrosion rates were found to be 0.00418 and 0.00232 mm/a for pure water and crude oil, respectively. However, for the mixtures of water and crude oil (with water content increased from 0.2 vol% to 10 vol%), the corrosion rate increased consistently and reached a maximum value of 0.15557 mm/a for 10 vol% water in crude oil. The effect of the concentration of various ions, namely, chloride, bicarbonate and sulfate in (oil/water) mixtures on the corrosion rate was characterized by weight-loss method. The results showed that with increasing the ions' concentrations, the corresponding exchange current density increased significantly. The results were further supported by the observations of corrosion morphology using scanning electron microscopy and are helpful in devising guidelines which would help in reducing corrosion in multipurpose transport pipelines involving a change of transported medium during their service life.

  10. Study of texture and microstructure evaluation of steel API 5L X70 under various thermomechanical cycles

    Energy Technology Data Exchange (ETDEWEB)

    Masoumi, Mohammad, E-mail: Mohammad@alu.ufc.br; Herculano, Luis Flavio Gaspar; Ferreira Gomes de Abreu, Hamilton

    2015-07-15

    This work studies the influence of different thermomechanical paths on the microstructure and crystallographic texture across the thickness of API 5L X70 pipeline steel manufactured via hot rolling using X-ray diffraction (XRD), scanning electron microscope (SEM), and electron backscattered diffraction (EBSD). The starting materials were controlled hot-rolled at 1000 °C to 44% and 67% reductions and subsequently heat treated with such processes as annealing, water quenching and quench tempering at three different temperatures to evaluate the microstructure and crystallographic texture changes across the thickness. The banded ferrite-pearlite microstructure of the initial material was changed to acicular ferrite, quasi-polygonal ferrite, granular bainite, martensite and retained austenite via different heat treatments. Moreover, different thermomechanical paths induced crystallographic texture variations across the thickness, e.g., {112}//ND, {111}//ND (γ fibre), and {011}//ND fibres dominated on the surface plane in contact with the rolls, whereas {001}//ND and particularly the (001)[1 1 0] texture component developed in the centre plane on which shear deformation has a zero value in this region. In this study, a simple interpretation of texture evolution was analyzed by comparison with the orientation changes that occurred during different rolling schedules and post-treatment processes.

  11. BEHAVIOUR CORROSION OF API 5L X70 AND API 5L X80 STEELS IN A CO2 MEDIUM BY SURFACE ANALYSIS AND ELECTROCHEMICAL TECHNIQUES

    OpenAIRE

    MILAGROS MABEL GUILLEN NUNEZ

    2006-01-01

    A seleção de materiais para o transporte de óleo e gás não é feita pela sua resistência à corrosão, mas sim pelas suas boas propriedades mecânicas, facilidade de fabricação e baixos custos. Devido às taxas de perda de material, causado pela corrosão interna, existe necessidade em se conhecer o comportamento dos aços de mais alta resistência, utilizados especialmente em gasodutos e oleodutos tais como API 5L X70 e API 5L X80. Um dos elementos responsáveis ...

  12. Hardness and microstructural characterization of API 5L X70 steel pipes welded by HF/ERW process; Caracterizacao microestrutural e de dureza em tubos de aco API 5L X70 soldados pelo processo HF/ERW

    Energy Technology Data Exchange (ETDEWEB)

    Calcada, Mauricio Vieira; Voorwald, Herman Jacobus Cornelis; Nascimento, Marcelino Pereira do [UNESP, Guaratingueta, SP (Brazil). Faculdade de Engenharia

    2010-07-01

    The materials that stand in the manufacture of steel pipes are called API, that should have, high mechanical resistance, high corrosion resistance, high fatigue resistance, good weldability, and other properties. Thus, the purpose of this project was to evaluate the microstructure and hardness of welded joints by the HF/ERW process of API 5L X70 steel pipes. The microstructural analysis was performed using a surface finish with grit sizes from 220 to 25 {mu}m e polishing with diamond paste from 9 {mu}m to 0.05 {mu}m; the revelation was made with 3% Nital attack. The Vickers hardness was performed across the welded joint by 33 points to indentation. The results were: 80.5 {+-} 3.4% of ferrite and 19.5 {+-} 3.4% of perlite for microanalysis. As for hardness, the values were: 215.69 HV10 for weld line, 218.65 HV10 for ZTA and 218.95 HV10 for base metal. (author)

  13. Acoustic emission during tensile deformation of M250 grade maraging steel

    Science.gov (United States)

    Mukhopadhyay, Chandan Kumar; Rajkumar, Kesavan Vadivelu; Chandra Rao, Bhaghi Purna; Jayakumar, Tamanna

    2012-05-01

    Acoustic emission (AE) generated during room temperature tensile deformation of varyingly heat treated (solution annealed and thermally aged) M250 grade maraging steel specimens have been studied. Deformation of microstructure corresponding to different heat treated conditions in this steel could be distinctly characterized using the AE parameters such as RMS voltage, counts and peak amplitude of AE hits (events).

  14. Mechanical characteristics of welded joints between different stainless steels grades

    Science.gov (United States)

    Topolska, S.; Łabanowski, J.

    2017-08-01

    Investigation of mechanical characteristics of welded joints is one of the most important tasks that allow determining their functional properties. Due to the very high, still rising, cost of some stainless steels it is justified, on economic grounds, welding austenitic stainless steel with steels that are corrosion-resistant like duplex ones. According to forecasts the price of corrosion resistant steels stil can increase by 26 ÷ 30%. For technical reasons welded joints require appropriate mechanical properties such as: tensile strength, bending, ductility, toughness, and resistance to aggressive media. Such joints are applied in the construction of chemical tankers, apparatus and chemical plants and power steam stations. Using the proper binder makes possible the welds directly between the elements of austenitic stainless steels and duplex ones. It causes that such joits behave satisfactorily in service in such areas like maritime constructions and steam and chemical plants. These steels have high mechanical properties such as: the yield strength, the tensile strength and the ductility as well as the resistance to general corrosion media. They are resistant to both pitting and stress corrosions. The relatively low cost of production of duplex steels, in comparison with standard austenitic steels, is inter alia, the result of a reduced amount of scarce and expensive Nickel, which is seen as a further advantage of these steels.

  15. Corrosion behavior of API 5L-X80 Pipeline steel for natural gas pipeline

    International Nuclear Information System (INIS)

    Mohd Asyadi Azam Mohd Abid; Imai, Hachiro

    2007-01-01

    Natural energy problem, including the environmental aspects had changes into certain circumstances in recent years and natural gas has been a focus of constant attention from the viewpoint of energy efficiency and pollution free. From that kind of background, pipeline construction for petroleum and natural gas were considerate as energy infrastructure maintenance plan. Based on the clarification of Asian Pipeline Project (1997-2007) centered in Japan, international pipeline is needed as the natural gas is mainly transported from gas field in Russia and Middle East to consumer country such as Japan etc. It used in severe condition such as cold district and sea. In the meantime, pipeline steel is not just received damages by earth crust fluctuation and corrosion, but also suffered from the corrosion caused by anions that were dissolved in sea and groundwater. The diversification of dispersion and consumption structure of natural gas supply acceptance base are seen regarding, that made the needs of the storing are rising and dealt with the quantitative spatial expansion of the demand. By that, corrosion resistance, not only the hardness, tough, weldability, corrosiveness gas environment is extremely required. (author)

  16. Estudo do comportamento do aço API 5L X80 quando submetido à soldagem por processo automatizado Study on the behavior of API 5L X80 steel when subjected to automated welding process

    Directory of Open Access Journals (Sweden)

    Siderley Fernandes Albuquerque

    2012-06-01

    Full Text Available No Brasil, a soldagem de tubulações tem sido praticamente de forma manual, entretanto, a utilização de processos de soldagem automatizados têm crescido muito nos últimos anos, contribuindo para o maior controle dos parâmetros de soldagem, e conseqüentemente, a possibilidade de obtenção de juntas soldadas com melhores propriedades mecânicas. A soldagem de tubulações com aço API 5L X80 ainda vem sendo avaliada no Brasil no que diz respeito aos melhores procedimentos, parâmetros e processos de soldagem; a aplicação de processos automatizados nas condições específicas de campo constitui em uma opção ainda incipiente no país por se discutir ainda a relação custo/benefício com a sua implantação. Logo, o objetivo deste trabalho é avaliar o comportamento na ZTA de juntas soldadas do aço API 5L X80 utilizados para transporte de petróleo e gás quando submetidos à soldagem com diferentes parâmetros, procedimentos e processos de soldagem, incluindo o processo automatizado; os resultados indicam além da redução da extensão e do tamanho de grão da ZTA a preservação da estrutura bainítica do metal de base nesta região nas soldagem executadas com processos automatizados.The welding of pipes has been largely manual in Brazil, however, the use of automated welding processes have greatly increased in recent years, contributing to greater control of welding parameters, and consequently, the possibility of obtaining welded joints with better mechanical properties. The welding of pipes of API 5L X80 steel has been evaluated in Brazil considering to best practices, parameters and welding processes; the implementation of automated processes in the specific field conditions is relevant project and innovative design in this area. Therefore, the objective is to evaluate the behavior in the HAZ of the API 5L X80 steel used for transporting oil and gas when subjected to automated welding processes; the results indicated besides the

  17. Effect of Heat Treatment on Microstructure and Hardness of Grade 91 Steel

    Directory of Open Access Journals (Sweden)

    Triratna Shrestha

    2015-01-01

    Full Text Available Grade 91 steel (modified 9Cr-1Mo steel is considered a prospective material for the Next Generation Nuclear Power Plant for application in reactor pressure vessels at temperatures of up to 650 °C. In this study, heat treatment of Grade 91 steel was performed by normalizing and tempering the steel at various temperatures for different periods of time. Optical microscopy, scanning and transmission electron microscopy in conjunction with microhardness profiles and calorimetric plots were used to understand the microstructural evolution including precipitate structures and were correlated with mechanical behavior of the steel. Thermo-Calc™ calculations were used to support the experimental work. Furthermore, carbon isopleth and temperature dependencies of the volume fraction of different precipitates were constructed.

  18. Study of verification and validation of standard welding procedure specifications guidelines for API 5L X-70 grade line pipe welding

    Directory of Open Access Journals (Sweden)

    Qazi H. A. A.

    2017-12-01

    Full Text Available Verification and validation of welding procedure specifications for X-70 grade line pipe welding was performed as per clause 8.2, Annexure B and D of API 5L, 45th Edition to check weld integrity in its future application conditions. Hot rolled coils were imported from China, de-coiling, strip edge milling, three roller bending to from pipe, inside and outside submerged arc welding of pipe, online ultrasonic testing of weld, HAZ and pipe body, cutting at fixed random length of pipe, visual inspection of pipe, Fluoroscopic inspection of pipe, welding procedure qualification test pieces marking at weld portion of the pipe, tensile testing, guided bend testing, CVN Impact testing were performed. Detailed study was conducted to explore possible explanations and variation in mechanical properties, WPS is examined and qualified as per API 5L 45th Edition.

  19. Uma breve revisão histórica do desenvolvimento da soldagem dos aços API para tubulações A brief history review of development on API steels welding for pipeline

    Directory of Open Access Journals (Sweden)

    Jaime Casanova Soeiro Junior

    2013-06-01

    Full Text Available Este trabalho enfoca o desenvolvimento dos aços API para tubulações desde o aço API 5L X42, desenvolvido em 1948, através de laminação a quente seguida de tratamento térmico. Desde então foram feitos diferentes desenvolvimentos visando aumentar a resistência mecânica e a tenacidade, além de melhorar a soldabilidade. Entre eles, a adição de elementos de liga, produzindo os aços ARBL e a utilização de rotas de processamento termomecânico durante a laminação. Inicialmente a rota utilizada era a laminação a quente controlada (TMCR, com utilização de elemento microligante como Nb para os aços X60 e o conjunto Nb e V para os aços X65 e X70, associado a uma redução do teor de carbono. Posteriormente foi implantada a rota de fabricação do aço por laminação controlada seguida de resfriamento controlado (TMCP, com redução de carbono e adição de Nb e Ti para os aços X80, e adições de Mo, Nb, Be Ti para os X100. A redução do carbono foi motivada também para melhorar a sua soldabilidade e, por este motivo, estes aços são soldados por diferentes processos de soldagem, como o eletrodo revestido. Desenvolvimentos recentes com raiz feita com MAG-TC e enchimento com arame tubular tem dado resultados animadores.This paper is a brief history on the development of pipelines steels since the API 5L X42 steel, developed in 1948 by hot rolling followed by heat treatment. Subsequently different developments were made to increase the strength and toughness of these materials, and to improve their weldability. Among them, the addition of microalloying elements, producing HSLA steels and thermomechanical processing routes during hot rolling. Initially the route used was the controlled hot rolling (TMCR, together with microalloying element such as Nb for X60 steel and Nb plus V for X65 and X70 steels, associated with a reduction in carbon content. Later, the thermomechanical controlled process (TMCP manufacturing route was

  20. Transformation kinetics of selected steel grades after plastic deformation

    Directory of Open Access Journals (Sweden)

    R. Kawulok

    2016-07-01

    Full Text Available The aim of this article was to assess the impact of previous plastic deformation on the kinetics of transformations of four selected steels. The research was conducted with use of the universal plastometer GLEEBLE 3800, when Continuous Cooling Transformation (CCT and Deformation Continuous Cooling Transformation (DCCT diagrams of selected steels were constructed on the basis of dilatometric tests. The research confirmed that the strain accelerates the particularly the transformations controlled by diffusion. Bainitic transformation was accelerated in three of the four steels. In the case of martensitic transformation the effect of the previous deformation was relatively small, but with clearly discernible trend.

  1. Assessment of long-term creep strength of grade 91 steel

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Kazuhiro; Sawada, Kota; Kushima, Hideaki [National Inst. for Materials Science, Tsukuba, Ibaraki (Japan)

    2010-07-01

    In 2004 and 2005 long-term creep rupture strength of ASME Grade 91 type steels of plate, pipe, forging and tube materials was evaluated in Japan by means of region splitting analysis method in consideration of 50% of 0.2% offset yield stress. According to the evaluated 100,000h creep rupture strength of 94MPa for plate, pipe and forging steels and 92MPa for tube steel at 600 C, allowable tensile stress of the steels regulated in the Interpretation for the Technical Standard for Thermal Power Plant was slightly reduced. New creep rupture data of the steels obtained in the long-term indicate further reduction of long-term creep rupture strength. Not only creep rupture strength, but also creep deformation property of the ASME Grade 91 steel was investigated and need of reevaluation of long-term creep strength of Grade 91 steel was indicated. A refinement of region splitting analysis method for creep rupture like prediction was discussed. (orig.)

  2. Study of API 5L X70 steel corrosion processes when in contact with some Brazilian soils; Estudo dos processos de corrosao de acos API 5L X70 em contato com alguns dos solos do Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Jesus, Sergio Luis de

    2007-07-01

    Pipelines, fuel storage tanks and other metallic structures are in permanent contact and exposed to different types of soils, of horizons or layers, or of soil aggressiveness. This interaction may cause expressive damages to the environment and to the planned work. Contamination may occur due to leakage of stored products, splitting during transportation, accidents caused by pipelines without extensive maintenance. The result of these accidents could be, among others, some financial losses. In order to recognize the dynamic interactions between metallic surfaces and the environment it is crucial to have preventive actions and to develop better-applied materials. API steel 5L X70 has been used in structures of low and high pressure with high mechanical strength and corrosion and, even so, it is susceptible to etching corrosion since it is in contact with different environments from mangrove regions to industrial environments. The present case evaluated the role of 5L X70 API steel in contact with different soil horizons representative of the Brazilian soil. This investigation correlated chemical species with solute ions in soil solution, secondary and primary phase minerals besides physical and chemical characteristics as pH, electric conductivity, total dissolved solids, among others, to the results of corrosion resistance and ways of corrosion. The evaluation was carried out using x-ray diffractometry, scanning electron microscopy, total reflection x-ray fluorescence, fuel injection flow besides texture and gravimetric analyses to soil characterization and mineralogy, identification of corrosion products, soil solution analyses, evaluation of tested materials and classification of ways and types of corrosion. This was an attempt to integrate the data to a better understanding of the process involving reagents and products. The results showed that different soil horizons such as different types of analyzed soils produce specific etching in metallic structures

  3. Improving production technology of tube steel grades in converter process

    Directory of Open Access Journals (Sweden)

    P. V. Kovalev

    2016-10-01

    Full Text Available Nature of formation and evolution special features of nonmetallic inclusions during ladle refining of converter HSLA steels for pipelines have been studied. Nonmetallic inclusions of the CaO-2O3-MgO system, close to calcium monoaluminate CaO∙Al2O3 with up to 5-6% of MgO, have been found as favorable from morphology point of view. These small inclusions nucleate on endogenous MgO substrates at sufficient high content of calcium in steel melt. Hot rolled plates can be rejected due to the coarse calcium bi- and hexa-aluminate inclusions (CaO∙22O3 and CaO∙62O3, usually containing exogenous MgO. These coarse inclusions form under calcium deficiency conditions, especially in the case of longtime steel holding in a ladle.

  4. Residual stress evaluation by X-Ray diffraction and hole-drilling in an API 5L X70 steel pipe bent by hot induction

    International Nuclear Information System (INIS)

    Ceglias, Rodrigo Braga; Alves, Juciane Maria; Botelho, Ramon Alves; Baeta Junior, Eustaquio de Souza; Santos, Igor Cuzzuol dos; Moraes, Nicki Robbers Darciano Cajueiro de; Oliveira, Rebeca Vieira de; Diniz, Saulo Brinco; Brandao, Luiz Paulo

    2016-01-01

    The API 5L X70 steel is used in high-pressure gas transmission pipelines. Because of this, knowledge of presence of residual stress and their magnitude is important to assess the material integrity in service. For the pipeline manufacturing, tubes need to be curved which is often made using the hot induction bending process. This process can introduce different residual stress depending of tube position. For this research, in order to evaluate the residual stress, was used an API 5L X70 tube that was previously curved by hot induction process. Samples were taken from the extrados, intrados, neutral line and straight section of the curved tube. Residual stresses were studied by two conventional methods: X-Ray Diffraction (XRD) and Hole-Drilling, which are destructive and non-destructive methods, respectively, in order to assess their qualitative responses. Each of these methods presents particular methodologies in sample preparation and material analysis, but also they differ in factors such time consumption and cost of the analysis. The qualitative responses obtained by the two different methods were comparable and satisfactory and pointed out the existence of a compressive residual stress state in steel pipe. (author)

  5. Residual stress evaluation by X-Ray diffraction and hole-drilling in an API 5L X70 steel pipe bent by hot induction

    Energy Technology Data Exchange (ETDEWEB)

    Ceglias, Rodrigo Braga; Alves, Juciane Maria; Botelho, Ramon Alves; Baeta Junior, Eustaquio de Souza; Santos, Igor Cuzzuol dos; Moraes, Nicki Robbers Darciano Cajueiro de; Oliveira, Rebeca Vieira de; Diniz, Saulo Brinco; Brandao, Luiz Paulo, E-mail: brandao@ime.eb.br [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil). Secao de Engenharia Mecanica e de Materiais

    2016-09-15

    The API 5L X70 steel is used in high-pressure gas transmission pipelines. Because of this, knowledge of presence of residual stress and their magnitude is important to assess the material integrity in service. For the pipeline manufacturing, tubes need to be curved which is often made using the hot induction bending process. This process can introduce different residual stress depending of tube position. For this research, in order to evaluate the residual stress, was used an API 5L X70 tube that was previously curved by hot induction process. Samples were taken from the extrados, intrados, neutral line and straight section of the curved tube. Residual stresses were studied by two conventional methods: X-Ray Diffraction (XRD) and Hole-Drilling, which are destructive and non-destructive methods, respectively, in order to assess their qualitative responses. Each of these methods presents particular methodologies in sample preparation and material analysis, but also they differ in factors such time consumption and cost of the analysis. The qualitative responses obtained by the two different methods were comparable and satisfactory and pointed out the existence of a compressive residual stress state in steel pipe. (author)

  6. Gas metal arc weldability of 1.5 GPa grade martensitic steels

    Science.gov (United States)

    Hwang, Insung; Yun, Hyeonsang; Kim, Dongcheol; Kang, Munjin; Kim, Young-Min

    2018-01-01

    The gas metal arc weldability of 1.5 GPa grade martensitic (MART) steel was evaluated using both inverter direct current (DC) and DC pulse power type welders, under conditions of different welding currents, welding speeds, and shielding gasses. By investigating the bead appearance, tensile strength, and arc stability, it was determined that DC pulse power is better than inverter DC power for arc welding of 1.3 mm thick 1.5 GPa grade MART steel. Further, from the results of the weldability for various shielding gases, it was determined that mixed shielding gas is more effective for welding 1.5 GPa grade MART steel than is pure inert gas (Ar) or active (CO2) gas. In the case of pure shielding gas, no sound bead was formed under any conditions. However, when the mixed shielding gas was used, sound and fine beads were obtained.

  7. Hydrogen induced cold cracking studies on armour grade high strength, quenched and tempered steel weldments

    Energy Technology Data Exchange (ETDEWEB)

    Magudeeswaran, G.; Balasubramanian, V. [Centre for Materials Joining Research (CEMAJOR), Department of Manufacturing Engineering, Annamalai University, Annamalai Nagar 608 002, Tamil Nadu (India); Madhusudhan Reddy, G. [Metal Joining Section, Defence Metallurgical Research Laboratory (DMRL), Kanchanbagh (P.O.) Hyderabad 560 058 Andhra Pradesh (India)

    2008-04-15

    Quenched and tempered (Q and T) steels are prone to hydrogen induced cracking (HIC) in the heat affected zone after welding. The use of austenitic stainless steel (ASS) consumables to weld the above steel was the only available remedy because of higher solubility for hydrogen in austenitic phase. The use of stainless steel consumables for a non-stainless steel base metal is not economical. Hence, alternate consumables for welding Q and T steels and their vulnerability to HIC need to be explored. Recent studies proved that low hydrogen ferritic (LHF) steel consumables can be used to weld Q and T steels, which can give very low hydrogen levels in the weld deposits. In this investigation an attempt has been made to study the influence of welding consumables and welding processes on hydrogen induced cold cracking of armour grade Q and T steel welds by implant testing. Shielded metal arc welding (SMAW) and flux cored arc welding (FCAW) processes were used for making welds using ASS and LHF welding consumables. ASS welds made using FCAW process offered a higher resistance to HIC than all other welds considered in this investigation. (author)

  8. Preventing the embrittling by hydrogen when galvanizing high-grade steel

    Energy Technology Data Exchange (ETDEWEB)

    Paatsch, W.

    1987-09-01

    Galvanic precipitation of a double layer consisting of a dull nickel layer overlaid with a brilliant zinc layer on low-alloyed high-strength steel grades leads to the forming of zinc-nickel alloy layers during the subsequent heat treatment. According to traction tests carried out on high-strength steel grades, as well as to hydrogen permeability tests, this process prevents embrittling by hydrogen which might be caused by galvanic process sequences - and creates a diffusion block at the same time. The alloy layers have an excellent corrosion resistance and temperature stability.

  9. Analisa Pengaruh Jenis Elektroda terhadap Laju Korosi pada Pengelasan Pipa API 5L Grade X65 dengan Media Korosi FeCl3

    Directory of Open Access Journals (Sweden)

    Gita Anggaretno

    2012-09-01

    Full Text Available Submarine pipelines (pipa bawah laut di desain untuk transportasi minyak, gas atau air dari lepas pantai menuju receiving point. Baja API 5L Grade X65 merupakan jenis pipa baja yang banyak digunakan pada pipa penyalur gas, air, dan minyak pada pipa bawah laut. Sistem perpipaan ini tidak mungkin terbentuk tanpa adanya proses las. Pengelasan Flux Cored Arc Welding (FCAW  merupakan las yang umum digunakan dalam struktur anjungan lepas pantai. Penelitian ini bertujuan untuk mengetahui pengaruh dari variasi elektroda pengelasan terhadap laju korosi pada pipa API 5L Grade X65. Variasi elektroda yang digunakan adalah elektroda spesifikasi AWS yaitu E7018, E6010 dan E6013. Metode pengujian korosi ini menggunakan bantuan sel tiga elektroda dengan media korosi FeCl3 yang mengacu pada ASTM G48. Dari pengujian ini didapatkan hasil laju korosi pada pengelasan pipa dengan elektroda E7018 adalah 0,53 mmpy, untuk elektroda E6013 adalah 0,69 mmpy, dan untuk E6010 adalah 0,62 mmpy. Perbedaan laju korosi tersebut dipengaruhi oleh tensile strength pada elektroda dan baja yang di las. Selisih kandungan unsur Mangan (Mn pada pipa dan elektroda las juga mempengaruhi perbedaan laju korosi pada pipa. Berdasarkan hasil foto SEM (Scanning Electron Microscope, secara morfologi permukaan weldmetal dengan nilai laju korosi paling tinggi, permukaanya terlihat lebih kasar. Akan tetapi laju korosi hasil las dengan elektroda-elektroda trsebut masih berada pada level yang diijinkan.

  10. Selective surface oxidation and segregation upon short term annealing of model alloys and industrial steel grades

    Energy Technology Data Exchange (ETDEWEB)

    Swaminathan, S.

    2007-07-01

    Segregation and selective oxidation phenomena of minor alloying elements during annealing of steel sheets lead to the formation of bare spots after hot-dip galvanizing. This thesis highlights the influence of annealing conditions and the effect of alloying elements on the selective oxidation in model alloys and some industrial steel grades. Model alloys of binary (Fe-2Si, Fe-2Mn, Fe-0.8Cr), ternary (Fe-2Mn-2Si, Fe-2Mn-0.8Cr, Fe-1Mn-0.8Cr, Fe-1Si-0.8Cr, Fe-2Si-0.8Cr) and quarternary (Fe-2Mn-2Si-0.8Cr) systems were studied. In the case of steels, standard grade interstitial free (IF) steels and experimental grade tensile strength 1000 MPa steel were investigated. All specimens were annealed at 820 C in N{sub 2}-5%H{sub 2} gas atmospheres with the wide range of dew points (i.e. -80 to 0 C). The surface chemistry after annealing and its wettability with liquid Zn have been correlated as a function of dew points by simulating the hot-dip galvanizing process at laboratory scale. (orig.)

  11. Study on the dynamic recrystallization model and mechanism of nuclear grade 316LN austenitic stainless steel

    International Nuclear Information System (INIS)

    Wang, Shenglong; Zhang, Mingxian; Wu, Huanchun; Yang, Bin

    2016-01-01

    In this study, the dynamic recrystallization behaviors of a nuclear grade 316LN austenitic stainless steel were researched through hot compression experiment performed on a Gleeble-1500 simulator at temperatures of 900–1250 °C and strain rates of 0.01–1 s −1 . By multiple linear regressions of the flow stress-strain data, the dynamic recrystallization mathematical models of this steel as functions of strain rate, strain and temperature were developed. Then these models were verified in a real experiment. Furthermore, the dynamic recrystallization mechanism of the steel was determined. The results indicated that the subgrains in this steel are formed through dislocations polygonization and then grow up through subgrain boundaries migration towards high density dislocation areas and subgrain coalescence mechanism. Dynamic recrystallization nucleation performs in grain boundary bulging mechanism and subgrain growth mechanism. The nuclei grow up through high angle grain boundaries migration. - Highlights: •Establish the DRX mathematical models of nuclear grade 316LN stainless steel •Determine the DRX mechanism of this steel •Subgrains are formed through dislocations polygonization. •Subgrains grow up through subgrain boundaries migration and coalescence mechanism. •DRX nucleation performs in grain boundary bulging mechanism and subgrain growth mechanism.

  12. Influence of precipitation behavior on mechanical properties and hydrogen induced cracking during tempering of hot-rolled API steel for tubing

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Joonoh, E-mail: mjo99@kims.re.kr [Ferrous Alloy Department, Advanced Metallic Materials Division, Korea Institute of Materials Science, 797 Changwondae-ro, Seongsan-gu, Changwon, Gyeongnam 642-831 (Korea, Republic of); Choi, Jongmin; Han, Seong-Kyung; Huh, Sungyul; Kim, Seong-Ju [Sheet Products Design Team, Technical Research Center, Hyundai Steel Company, 1480 Bukbusaneop-ro, Dangjin, Chungnam 343-823 (Korea, Republic of); Lee, Chang-Hoon; Lee, Tae-Ho [Ferrous Alloy Department, Advanced Metallic Materials Division, Korea Institute of Materials Science, 797 Changwondae-ro, Seongsan-gu, Changwon, Gyeongnam 642-831 (Korea, Republic of)

    2016-01-15

    Precipitation behavior and its effect on hydrogen embrittlement during tempering process of hot-rolled API steel designed with 0.4 wt% Cr and 0.25 wt% Mo were investigated. The base steel was normalized and then tempered at 650 °C for up to 60 min. The precipitation behavior of the examined steel was explored using transmission electron microscopy (TEM) analysis, and it was found that the precipitation sequence during tempering at 650 °C were as follows: MX+M{sub 3}C→MX→MX+M{sub 7}C{sub 3}+M{sub 23}C{sub 6}. The change of particle fraction was measured by electrolytic extraction technique. At the early stage of tempering, the particle fraction greatly decreased due to dissolution of M{sub 3}C particle, and increased after 10 min by the precipitation of M{sub 7}C{sub 3} and M{sub 23}C{sub 6} particles. The particle fraction showed a peak at 30 min tempering and decreased again due to the dissolution of M{sub 7}C{sub 3} particle. Vickers hardness tests of base steel and tempered samples were carried out, and then the hardness was changed by accompanying with the change of particle fraction. The sensitivity of hydrogen embrittlement was evaluated through hydrogen induced cracking (HIC) tests, and the results clearly proved that HIC resistance of tempered samples was better than that of base steel due to the formation of tempered martensite, and then the HIC resistance changed depending on the precipitation behavior during tempering, i.e., the precipitation of coarse M{sub 23}C{sub 6} and M{sub 7}C{sub 3} particles deteriorated the HIC resistance.

  13. Influence of precipitation behavior on mechanical properties and hydrogen induced cracking during tempering of hot-rolled API steel for tubing

    International Nuclear Information System (INIS)

    Moon, Joonoh; Choi, Jongmin; Han, Seong-Kyung; Huh, Sungyul; Kim, Seong-Ju; Lee, Chang-Hoon; Lee, Tae-Ho

    2016-01-01

    Precipitation behavior and its effect on hydrogen embrittlement during tempering process of hot-rolled API steel designed with 0.4 wt% Cr and 0.25 wt% Mo were investigated. The base steel was normalized and then tempered at 650 °C for up to 60 min. The precipitation behavior of the examined steel was explored using transmission electron microscopy (TEM) analysis, and it was found that the precipitation sequence during tempering at 650 °C were as follows: MX+M_3C→MX→MX+M_7C_3+M_2_3C_6. The change of particle fraction was measured by electrolytic extraction technique. At the early stage of tempering, the particle fraction greatly decreased due to dissolution of M_3C particle, and increased after 10 min by the precipitation of M_7C_3 and M_2_3C_6 particles. The particle fraction showed a peak at 30 min tempering and decreased again due to the dissolution of M_7C_3 particle. Vickers hardness tests of base steel and tempered samples were carried out, and then the hardness was changed by accompanying with the change of particle fraction. The sensitivity of hydrogen embrittlement was evaluated through hydrogen induced cracking (HIC) tests, and the results clearly proved that HIC resistance of tempered samples was better than that of base steel due to the formation of tempered martensite, and then the HIC resistance changed depending on the precipitation behavior during tempering, i.e., the precipitation of coarse M_2_3C_6 and M_7C_3 particles deteriorated the HIC resistance.

  14. Stress corrosion cracking of L-grade stainless steels in boiling water reactor (BWR) plants

    International Nuclear Information System (INIS)

    Suzuki, Shunichi; Fukuda, Toshihiko; Yamashita, Hironobu

    2004-01-01

    L-grade stainless steels as 316NG, SUS316L and SUS304L have been used for the BWR reactor internals and re-circulation pipes as SCC resistant materials. However, SCC of the L-grade material components were reported recently in many Japanese BWR plants. The detail investigation of the components showed the fabrication process such as welding, machining and surface finishing strongly affected SCC occurrence. In this paper, research results of SCC of L-grade stainless steels, metallurgical investigation of core shrouds and re-circulation pipings, and features of SCC morphology were introduced. Besides, the structural integrity of components with SCC, countermeasures for SCC and future R and D planning were introduced. (author)

  15. Efficiency and corrosion rate analysis of organic inhibitor utilization from bawang dayak leaves (EleutherineamericanaMerr.) on API 5L steel

    Science.gov (United States)

    Sari, Shaimah Rinda; Sari, Eli Novita; Rizky, Yoel; Sulistijono, Triana, Yunita

    2018-05-01

    This research studied the inhibition of corrosion by bawang dayak leaves extract (EleutherineamericanaMerr.) on API 5L steel in brine water environment (3.5% NaCl). The inhibitor was extracted using maceration process from bawang dayak leaves that was cultivated in Paser District, East Kalimantan. The test of antioxidant activity showed that bawang dayak leaves extract is a very powerful antioxidant with IC50 value of 27.30204. The results from FTIR test show the presence of electronegative atoms and double bonds of the alkenes groups that provide the potential of the extract as a corrosion inhibitor. Efficiency of inhibition reached up to 93.158% for the addition of inhibitor with 300 ppm concentration and 20 days of immersion time. This inhibitory behavior is also supported by polarization measurements where the lowest corrosion rate of 0.00128 mm/year is obtained at the same concentration and immersion time.

  16. Corrosion Cyclic Voltammetry of Two Types of Heat-Affected Zones (HAZs) of API-X100 Steel in Bicarbonate Solutions

    Science.gov (United States)

    Eliyan, Faysal Fayez; Alfantazi, Akram

    2014-12-01

    This paper examined the electrochemical corrosion behavior and corrosion products of two types of heat-affected HAZs made from API-X100 steel. Cyclic voltammetry, with different scan rates and potential ranges at 10 cycles, was applied to analyze the interdependent corrosion reactions of cathodic reduction, anodic dissolution, passivation, and transpassivation. The HAZ cooled at 60 K/s, from a peak temperature of 1470 K (1197 °C) that was held for 15 seconds, exhibited better passivation and lower cathodic activity than the HAZ cooled at 10 K/s. Increasing bicarbonate concentration, from 0.05 and 0.2 to 0.6 M, increases the anodic activity and cathodic reduction, but accordingly protects the active surfaces and enhances passivation.

  17. The Effect of Impingement Velocity and Angle Variation on the Erosion Corrosion Performance of API 5L-X65 Carbon Steel in a Flow Loop

    Directory of Open Access Journals (Sweden)

    Ihsan UlHaq Toor

    2018-05-01

    Full Text Available Erosion corrosion performance of API 5L-X65 carbon steel was investigated at three different impingement velocities (3, 6 & 12 m/s, five different angles (15, 30, 45, 60, & 90°, and with/without solid particles (average particle size of 314 µm. The experiments were conducted in 0.2 M NaCl solution at room temperature for a duration of 24 h and the results showed that the maximum erosion corrosion rate was observed at 45° irrespective of the velocity. The highest erosion corrosion rate at 45° was due to the balance between the shear and normal impact stress at this angle. Ploughing, deep craters, and micro-forging/plastic deformation were found to be the main erosion corrosion mechanisms. The maximum wear scar depth measured using optical profilometery was found to be 51 µm (average at an impingement angle of 45°.

  18. Effect of Microstructure on Hydrogen Diffusion in Weld and API X52 Pipeline Steel Base Metals under Cathodic Protection

    Directory of Open Access Journals (Sweden)

    R. C. Souza

    2017-01-01

    Full Text Available The aim of this research was to evaluate the influence of microstructure on hydrogen permeation of weld and API X52 base metal under cathodic protection. The microstructures analyzed were of the API X52, as received, quenched, and annealed, and the welded zone. The test was performed in base metal (BM, quenched base metal (QBM, annealed base metal (ABM, and weld metal (WM. Hydrogen permeation flows were evaluated using electrochemical tests in a Devanathan cell. The potentiodynamic polarization curves were carried out to evaluate the corrosion resistance of each microstructure. All tests were carried out in synthetic soil solutions NS4 and NS4 + sodium thiosulfate at 25°C. The sodium thiosulfate was used to simulate sulfate reduction bacteria (SRB. Through polarization, assays established that the microstructure does not influence the corrosion resistance. The permeation tests showed that weld metal had lower hydrogen flow than base metal as received, quenched, and annealed.

  19. Obtaining and analysis of results of fatigue and corrosion-fatigue in steel API 5L X60; Obtencao e analise de resultados de fadiga e corrosao-fadiga em aco API 5L X60

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Bruno Allison [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais; Silva, Antonio Almeida; Santos, Fabio Gualberto Chagas [Universidade Federal de Campina Grande (UFCG), PB (Brazil)

    2008-07-01

    The corrosion process allied to the fatigue, due to repetitive efforts of several natures, is the main responsible for the damages in pipeline and offshore structures that results in the appears of located faults, and by the way can results in leaks and financial and environmental loss. This phenomenon calls corrosion-fatigue, however, it is very complex, and mainly, in what it concerns the form as this it develops in the structure. The objective of this work is to present some results of experimental fatigue tests and corrosion-fatigue accomplished with specimen that the material originated a pipeline steel API 5L X60. The tests developed in a machine which could test until 12 specimens per time. For test of corrosion-fatigue was used a cell-of-corrosion especially projected, in this way simulated an aggressive environmental condition in a corrosion conditions. With the results of tests, was possible estimate the fatigue limits of the specimen when submitted to the repeated flexing, and compare it with evaluate corrosion-fatigue graphs, that as the literature comes moved down of the curve, in relation to the fatigue curve. (author)

  20. Ductile Tearing Resistance Indexing of Automotive Grade DP 590 Steel Sheets: EWF Testing Using DENT Specimens

    Science.gov (United States)

    Sahoo, Subhadra; Padmapriya, N.; De, Partha Sarathi; Chakraborti, P. C.; Ray, S. K.

    2018-03-01

    The essential work of fracture (EWF) method has been explored for indexing the ductile tearing resistance of DP 590 automotive grade dual-phase steel sheet both in longitudinal (L-T) and transverse (T-L) orientations. The simplest possible test and analysis procedures have been adopted. The EWF method is found to be eminently suitable for routine quality control and product development purposes for such materials. Areas for further research for improving the experimental strategy are highlighted. For the investigated steel sheet, the estimated tearing resistance is found to be distinctly higher for the L-T orientation compared to the T-L orientation; the reason thereof merits further investigation.

  1. Behavior of Low Grade Steel Fiber Reinforced Concrete Made with Fresh and Recycled Brick Aggregates

    Directory of Open Access Journals (Sweden)

    Md. Shariful Islam

    2017-01-01

    Full Text Available In recent years, recycled aggregates from construction and demolition waste (CDW have been widely accepted in construction sectors as the replacement of coarse aggregate in order to minimize the excessive use of natural resources. In this paper, an experimental investigation is carried out to observe the influence of low grade steel fiber reinforcements on the stress-strain behavior of concrete made with recycled and fresh brick aggregates. In addition, compressive strength by destructive and nondestructive tests, splitting tensile strength, and Young’s modulus are determined. Hooked end steel wires with 50 mm of length and an aspect ratio of 55.6 are used as fiber reinforcements in a volume fraction of 0% (control case, 0.50%, and 1.00% in concrete mixes. The same gradation of aggregates and water-cement ratio (w/c=0.44 were used to assess the effect of steel fiber in all these concrete mixes. All tests were conducted at 7, 14, and 28 days to perceive the effect of age on different mechanical properties. The experimental results show that around 10%~15% and 40%~60% increase in 28 days compressive strength and tensile strength of steel fiber reinforced concrete, respectively, compared to those of the control case. It is observed that the effect of addition of 1% fiber on the concrete compressive strength is little compared to that of 0.5% steel fiber addition. On the other hand, strain of concrete at failure of steel fiber reinforced concrete has increased almost twice compared to the control case. A simple analytical model is also proposed to generate the ascending portions of the stress-strain curve of concrete. There exists a good correlation between the experimental results and the analytical model. A relatively ductile failure is observed for the concrete made with low grade steel fibers.

  2. Texture evolution of experimental silicon steel grades. Part I: Hot rolling

    Energy Technology Data Exchange (ETDEWEB)

    Sandoval Robles, J.A., E-mail: jsandoval.uanl@yahoo.com [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, Ave. Universidad S/N, Cd. Universitaria, San Nicolás de los Garza, Nuevo León C.P. 66450 (Mexico); Salas Zamarripa, A.; Guerrero Mata, M.P. [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, Ave. Universidad S/N, Cd. Universitaria, San Nicolás de los Garza, Nuevo León C.P. 66450 (Mexico); Cabrera, J. [Universitat Politècnica de Catalunya, Departament de Ciència dels Materials I Enginyeria Metal-lúrgica, Av. Diagonal 647, Barcelona 08028 (Spain)

    2017-05-01

    The metallurgical understanding of the deformation processes during the fabrication of non-oriented electrical steels plays a key role in improving their final properties. Texture control and optimization is critical in these steels for the enhancement of their magnetic properties. The aim of the present work is to study the texture evolution of six non-oriented experimental silicon steel grades during hot rolling. These steels were low carbon steel with a silicon content from 0.5 to 3.0 wt%. The first rolling schedule was performed in the austenitic (γ-Fe) region for the steel with a 0.5 wt% of silicon content, while the 1.0 wt% silicon steel was rolled in the two-phase (α+γ) region. Steels with higher silicon content were rolled in the ferritic (α-Fe) region. The second rolling schedule was performed in the α-Fe region. Samples of each stage were analyzed by means of Electron Backscatter Diffraction (EBSD). Findings showed that the texture was random and heterogeneous in all samples after 60% of rolling reduction, which is due to the low deformation applied during rolling. After the second rolling program, localized deformation and substructured grains near to surface were observed in all samples. The Goss {110}<001>texture-component was found in the 0.5 and 1.0 wt.-%silicon steels. This is due to the thermomechanical conditions and the corresponding hot band microstructure obtained after the first program. Moreover, the α<110>//RD and the γ <111>//ND fiber components of the texture presented a considerable increment as the silicon content increases. Future research to be published soon will be related to the texture evolution during the cold-work rolling process. - Highlights: • We analyze six silicon steel experimental grades alloys trough the rolling process. • Material was subjected to a hot deformation process in the α-γ region. • No recrystalization was observed during-after the rolling schedules. • Rise of the magnetic texture components

  3. High temperature deformation behavior, thermal stability and irradiation performance in Grade 92 steel

    Science.gov (United States)

    Alsagabi, Sultan

    The 9Cr-2W ferritic-martensitic steel (i.e. Grade 92 steel) possesses excellent mechanical and thermophysical properties; therefore, it has been considered to suit more challenging applications where high temperature strength and creep-rupture properties are required. The high temperature deformation mechanism was investigated through a set of tensile testing at elevated temperatures. Hence, the threshold stress concept was applied to elucidate the operating high temperature deformation mechanism. It was identified as the high temperature climb of edge dislocations due to the particle-dislocation interactions and the appropriate constitutive equation was developed. In addition, the microstructural evolution at room and elevated temperatures was investigated. For instance, the microstructural evolution under loading was more pronounced and carbide precipitation showed more coarsening tendency. The growth of these carbide precipitates, by removing W and Mo from matrix, significantly deteriorates the solid solution strengthening. The MX type carbonitrides exhibited better coarsening resistance. To better understand the thermal microstructural stability, long tempering schedules up to 1000 hours was conducted at 560, 660 and 760°C after normalizing the steel. Still, the coarsening rate of M23C 6 carbides was higher than the MX-type particles. Moreover, the Laves phase particles were detected after tempering the steel for long periods before they dissolve back into the matrix at high temperature (i.e. 720°C). The influence of the tempering temperature and time was studied for Grade 92 steel via Hollomon-Jaffe parameter. Finally, the irradiation performance of Grade 92 steel was evaluated to examine the feasibility of its eventual reactor use. To that end, Grade 92 steel was irradiated with iron (Fe2+) ions to 10, 50 and 100 dpa at 30 and 500°C. Overall, the irradiated samples showed some irradiation-induced hardening which was more noticeable at 30°C. Additionally

  4. Weldability and microstructural analysis of nuclear-grade austenitic stainless steels

    International Nuclear Information System (INIS)

    Lee, C.H.

    1988-01-01

    This study evaluated the hot-ductility response, and hot-cracking susceptibility (fusion-zone solidification cracking and HAZ liquation cracking) of modified nuclear-grade and standard austenitic stainless steels. Extensive microstructural characterization using state-of-the-art analytical electron microscopy (TEM and STEM) as well as SEM (EDAX) and OLM was performed to correlate the material behavior with metallurgical characteristics. In addition, studies of the effect of Si, N, and rare earth elements on hot-cracking susceptibility, significance of the ductility dip phenomena and backfilled solidification cracks were also performed. Furthermore, based on the metallurgical evaluation, the possible mechanisms involved in solidification cracking and HAZ liquation cracking of the modified alloys are proposed. Finally, the optimized chemical specifications and requirements for nuclear-grade stainless steels are also suggested

  5. Project of neural network for steel grade selection with the assumed CCT diagram

    OpenAIRE

    S. Malara; L.A. Dobrzański; J. Trzaska

    2008-01-01

    Purpose: The aim of this paper was developing a project of neural network for selection of steel grade with the specified CCT diagram – structure and of harness after heat treatment.Design/methodology/approach: The goal has been achieved in the following stages: at the first stage characteristic points of CCT diagram have been determined. At the second stage neural network has been developed and optimized.Findings: The neural network was developed in this paper, that allowed selection of stee...

  6. Characterization of Aging Behavior in M250 Grade Maraging Steel Using Ultrasonic Measurements

    Science.gov (United States)

    Rajkumar, K. V.; Kumar, Anish; Jayakumar, T.; Raj, Baldev; Ray, K. K.

    2007-02-01

    Ultrasonic measurements have been carried out in M250 grade maraging steel specimens subjected to solution annealing at 1093 K for 1 hour followed by aging at 755 K for various durations in the range of 0.25 to 100 hours. The influence of aging on microstructure, room temperature hardness, and ultrasonic parameters (longitudinal and shear wave velocities and Poisson’s ratio) has been studied in order to derive correlations among these parameters in aged M250 maraging steel. Both hardness and ultrasonic velocities exhibit almost similar behaviors with aging time. They increase with the precipitation of intermetallic phases, Ni3Ti and Fe2Mo, and decrease with the reversion of martensite to austenite. Ultrasonic shear wave velocity is found to be more influenced by the precipitation of intermetallic phases, whereas longitudinal wave velocity is influenced more by the reversion of martensite to austenite. Unlike hardness and ultrasonic velocities, the Poisson’s ratio exhibits a monotonous decrease with aging time and, hence, can be used for unambiguous monitoring of the aging process in M250 maraging steel. Further, none of the parameters, i.e., hardness, ultrasonic velocity, or Poisson’s ratio, alone could identify the initiation of the reversion of austenite at early stage; however, the same could be identified from the correlation between ultrasonic velocity and Poisson’s ratio, indicating the advantage of using the multiparametric approach for comprehensive characterization of complex aging behavior in M250 grade maraging steel.

  7. Optimization of BI test parameters to investigate mechanical properties of Grade 92 steel

    Science.gov (United States)

    Barbadikar, Dipika R.; Vincent, S.; Ballal, Atul R.; Peshwe, Dilip R.; Mathew, M. D.

    2018-04-01

    The ball indentation (BI) testing is used to evaluate the tensile properties of materials namely yield strength, strength coefficient, ultimate tensile strength, and strain hardening exponent. The properties evaluated depend on a number of BI test parameters. These parameters include the material constants like yield slope (YS), constraint factor (CF), yield offset parameter (YOP). Number of loading/unloading cycles, preload, indenter size and depth of penetration of indenter also affects the properties. In present investigation the effect of these parameters on the stress-strain curve of normalized and tempered Grade 92 steel is evaluated. Grade 92 is a candidate material for power plant application over austenitic stainless steel and derives its strength from M23C6, MX precipitates and high dislocation density. CF, YS and YOP changed the strength properties considerably. Indenter size effect resulted in higher strength for smaller indenter. It is suggested to use larger indenter diameter and higher number of loading cycles for GRADE 92 steel to get best results using BI technique.

  8. Effect of welding processes and consumables on fatigue crack growth behaviour of armour grade quenched and tempered steel joints

    Directory of Open Access Journals (Sweden)

    G. Magudeeswaran

    2014-03-01

    Full Text Available Quenched and Tempered (Q&T steels are widely used in the construction of military vehicles due to its high strength to weight ratio and high hardness. These steels are prone to hydrogen induced cracking (HIC in the heat affected zone (HAZ after welding. The use of austenitic stainless steel (ASS consumables to weld the above steel was the only available remedy because of higher solubility for hydrogen in austenitic phase. The use of stainless steel consumables for a non-stainless steel base metal is not economical. Hence, alternate consumables for welding Q&T steels and their vulnerability to HIC need to be explored. Recent studies proved that low hydrogen ferritic steel (LHF consumables can be used to weld Q&T steels, which can give very low hydrogen levels in the weld deposits. The use of ASS and LHF consumables will lead to distinct microstructures in their respective welds. This microstructural heterogeneity will have a drastic influence in the fatigue crack growth resistance of armour grade Q&T steel welds. Hence, in this investigation an attempt has been made to study the influence of welding consumables and welding processes on fatigue crack growth behaviour of armour grade Q&T Steel joints. Shielded metal arc welding (SMAW and Flux cored arc welding (FCAW were used for fabrication of joints using ASS and LHF consumables. The joints fabricated by SMAW process using LHF consumable exhibited superior fatigue crack growth resistance than all other joints.

  9. Effects of aggregate grading on the properties of steel fibre-reinforced concrete

    Science.gov (United States)

    Acikgens Ulas, M.; Alyamac, K. E.; Ulucan, Z. C.

    2017-09-01

    This study investigates the effects of changing the aggregate grading and maximum aggregate size (D max ) on the workability and mechanical properties of steel fibre-reinforced concrete (SFRC). Four different gradations and two different D max were used to produce SFRC mixtures with constant cement dosages and water/cement ratios. Twelve different concrete series were tested. To observe the properties of fresh concrete, slump and Ve-Be tests were performed immediately after the mixing process to investigate the effects of time on workability. The hardened properties, such as the compressive, splitting tensile and flexural strengths, were also evaluated. In addition, the toughness of the SFRC was calculated. Based on our test results, we can conclude that the grading of the aggregate and the D max have remarkable effects on the properties of fresh and hardened SFRC. In addition, the toughness of the SFRC was influenced by changing the grading of the aggregate and the D max .

  10. Microstructural Evolution and Constitutive Relationship of M350 Grade Maraging Steel During Hot Deformation

    Science.gov (United States)

    Chakravarthi, K. V. A.; Koundinya, N. T. B. N.; Narayana Murty, S. V. S.; Nageswara Rao, B.

    2017-03-01

    Maraging steels exhibit extraordinary strength coupled with toughness and are therefore materials of choice for critical structural applications in defense, aerospace and nuclear engineering. Thermo-mechanical processing is an important step in the manufacture of these structural components. This process assumes significance as these materials are expensive and the mechanical properties obtained depend on the microstructure evolved during thermo-mechanical processing. In the present study, M350 grade maraging steel specimens were hot isothermally compressed in the temperature range of 900-1200 °C and in the strain rate range of 0.001-100 s-1, and true stress-true strain curves were generated. The microstructural evolution as a function of strain rate and temperature in the deformed compression specimens was studied. The effect of friction between sample and compression dies was evaluated, and the same was found to be low. The measured flow stress data was used for the development of a constitutive model to represent the hot deformation behavior of this alloy. The proposed equation can be used as an input in the finite element analysis to obtain the flow stress at any given strain, strain rate, and temperature useful for predicting the flow localization or fracture during thermo-mechanical simulation. The activation energy for hot deformation was calculated and is found to be 370.88 kJ/mol, which is similar to that of M250 grade maraging steel.

  11. Material properties of Grade 91 steel at elevated temperature and their comparison with a design code

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyeong Yeon; Kim, Woo Gon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, Han Sang; Kim, Yun Jae [Korea Univ., Seoul (Korea, Republic of)

    2013-10-15

    In this study, the material properties of tensile strength, creep properties, and creep crack growth model for Gr.91 steel at elevated temperature were obtained from material tests at KAERI, and the test data were compared with those of the French elevated temperature design code, RCC-MRx. The conservatism of the material properties in the French design code is highlighted. Mod.9Cr-1Mo (ASME Grade 91; Gr.91) steel is widely adopted as candidate material for Generation IV nuclear systems as well as for advanced thermal plants. In a Gen IV sodium-cooled fast reactor of the PGSFR (Prototype Gen IV Sodium-cooled Fast Reactor) being developed by KAERI (Korea Atomic Energy Research Institute), Gr.91 steel is selected as the material for the steam generator, secondary piping, and decay heat exchangers. However, as this material has a relatively shorter history of usage in an actual plant than austenitic stainless steel, there are still many issues to be addressed including the long-term creep rupture life extrapolation and ratcheting behavior with cyclic softening characteristics.

  12. Statistical analysis of fatigue crack growth behavior for grade B cast steel

    International Nuclear Information System (INIS)

    Li, W.; Sakai, T.; Li, Q.; Wang, P.

    2011-01-01

    Tests for fatigue crack growth rate (FCGR) and crack-tip opening displacement (CTOD) were performed to clarify the fatigue crack growth behavior of a railway grade B cast steel. The threshold values of this steel with specific survival probabilities are evaluated, in which the mean value is 8.3516 MPa m 1/2 , very similar to the experimental value, about 8.7279 MPa m 1/2 . Under the conditions of plane strain and small-scale yielding, the values of fracture toughness for this steel with specific survival probabilities are converted from the corresponding critical CTOD values, in which the mean value is about 138.4256 MPa m 1/2 . In consideration of the inherent variability of crack growth rates, six statistical models are proposed to represent the probabilistic FCGR curves of this steel in entire crack propagation region from the viewpoints of statistical evaluation on the number of cycles at a given crack size and the crack growth rate at a given stress intensity factor range, stochastic characteristic of crack growth as well as statistical analysis of coefficient and exponent in FCGR power law equation. Based on the model adequacy checking, result shows that all models are basically in good agreement with test data. Although the probabilistic damage-tolerant design based on some models may involve a certain amount of risk in stable crack propagation region, they just accord with the fact that the dispersion degree of test data in this region is relatively smaller.

  13. Interpretation and significance of reverse chevron-shaped markings on fracture surfaces of API X100 pipeline steels

    International Nuclear Information System (INIS)

    Sowards, Jeffrey W.; McCowan, Chris N.; Drexler, Elizabeth S.

    2012-01-01

    Highlights: ► We investigated fractures of X100 steel linepine produced during fracture mechanics testing. ► Fractures exhibited a unique chevron pattern that points in the direction of crack propagation. ► A qualitative model is proposed to explain the fracture pattern formation. ► Findings indicate that careful interpretation of ductile material fractures is necessary. - Abstract: Fracture surfaces of X100 pipeline steels were examined with optical and electron microscopy after crack tip opening angle fracture testing. Some fracture surfaces exhibited chevron-shaped fracture patterns that are markedly different from classic chevron fracture. The chevron-shaped markings on the X100 fracture surfaces point in the direction of crack growth, rather than towards the location of fracture initiation, as observed in classic cases of chevron fracture. Existing models, predicting formation of chevron fracture patterns, do not explain the fracture behavior observed for X100 steel. A mechanism is proposed where reverse chevron-shaped patterns are developed due to the shape of the crack front itself. The chevron shape forms as a result of crack tunneling, and the overall pattern is developed on the fracture surface due to intermittent crack growth, resulting in alternating regions (bands) of fast fracture and slower, more ductile fracture. The contrast between these bands of alternating fracture defines the chevron. Care should be taken during interpretation of intermittent chevron markings on fractures of ductile materials, as they may point away from rather than towards the origin of fracture.

  14. Parametric study of development of Inconel-steel functionally graded materials by laser direct metal deposition

    International Nuclear Information System (INIS)

    Shah, Kamran; Haq, Izhar ul; Khan, Ashfaq; Shah, Shaukat Ali; Khan, Mushtaq; Pinkerton, Andrew J

    2014-01-01

    Highlights: • Functionally graded steel and nickel super-alloy structures have been developed. • Mechanical properties of FGMs can be controlled by process input parameters. • SDAS is strongly dependent on the laser power and powder mass flow rate. • Carbides provide a mechanism to control the hardness and wear resistance of FGM. • Tensile strength of FGM is dependent on the laser power and powder mass flow rate. - Abstract: Laser direct metal deposition (LDMD) has developed from a prototyping to a single and multiple metals manufacturing technique. It offers an opportunity to produce graded components, with differing elemental composition, phase and microstructure at different locations. In this work, continuously graded Stainless Steel 316L and Inconel 718 thin wall structures made by direct laser metal deposition process have been explored. The paper considers the effects of process parameters including laser power levels and powder mass flow rates of SS316L and Inconel 718 during the deposition of the Steel–Ni graded structures. Microstructure characterisation and phase identification are performed by optical microscopy and X-ray diffraction techniques. Mechanical testing, using methods such as hardness, wear resistance and tensile testing have been carried out on the structures. XRD results show the presence of the NbC and Fe 2 Nb phases formed during the deposition. The effect of experimental parameters on the microstructure and physical properties are determined and discussed. Work shows that mechanical properties can be controlled by input parameters and generation of carbides provides an opportunity to selectively control the hardness and wear resistance of the functionally graded material

  15. Recalls API

    Data.gov (United States)

    General Services Administration — This Recalls API allows you to tap into a list of (1) drug and food safety recalls from the Food and Drug Administration, Food Safety and Inspection Service, and...

  16. Jobs API

    Data.gov (United States)

    General Services Administration — This Jobs API returns job openings across the federal government and includes all current openings posted on USAJobs.gov that are open to the public and located in...

  17. Heat Transfer Analysis of Localized Heat-Treatment for Grade 91 Steel

    Science.gov (United States)

    Walker, Jacob D.

    Many of the projects utilizing Grade 91 steel are large in scale, therefore it is necessary to assemble on site. The assembly of the major pieces requires welding in the assembly; this drastically changes the superior mechanical properties of Grade 91 steel that it was specifically developed for. Therefore, because of the adverse effects of welding on the mechanical properties of Grade 91, it is necessary to do a localized post weld heat treatment. As with most metallic materials grade 91 steel requires a very specific heat treatment process. This process includes a specific temperature and duration at that temperature to achieve the heat treatment desired. Extensive research has been done to determine the proper temperatures and duration to provide the proper microstructure for the superior mechanical properties that are inherent to Grade 91 steel. The welded sections are typically large structures that require local heat treatments and cannot be placed in an oven. The locations of these structures vary from indoors in a controlled environment to outdoors with unpredictable environments. These environments can be controlled somewhat, however in large part the surrounding conditions are unchangeable. Therefore, there is a need to develop methods to accurately apply the surrounding conditions and geometries to a theoretical model in order to provide the proper requirements for the local heat treatment procedure. Within this requirement is the requirement to define unknowns used in the heat transfer equations so that accurate models can be produced and accurate results predicted. This study investigates experimentally and numerically the heat transfer and temperature fields of Grade 91 piping in a local heat treatment. The objective of this thesis research is to determine all of the needed heat transfer coefficients. The appropriate heat transfer coefficients are determined through the inverse heat conduction method utilizing a ceramic heat blanket. This will be done

  18. Erosion-Oxidation Response of Boiler Grade Steels: A Mathematical Investigation

    Directory of Open Access Journals (Sweden)

    S. K. Das

    2008-01-01

    Full Text Available A ductile erosion model embodying the mechanisms of erosion involving cutting wear and repeated plastic deformation has been developed to predict erosion rates of boiler grade steels. The issue of erosion-oxidation interaction has also been addressed to further predict the mass loss resulted from this composite mechanism. A deterministic formalism for the kinetics of oxide-scale growth and a probabilistic approach to characterize the material loss are employed to describe simultaneous actions of high-temperature oxidation and mechanical erosion. The model predictions are in good agreement with the published data.

  19. Variations of microstructure and properties of 690 MPa grade low carbon bainitic steel after tempering

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Rui [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan Shandong 250061 (China); School of Materials Science and Engineering, Shandong University, Jinan Shandong 250061 (China); Li, Shengli, E-mail: lishengli@sdu.edu.cn [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan Shandong 250061 (China); School of Materials Science and Engineering, Shandong University, Jinan Shandong 250061 (China); Li, Zhenshun; Tian, Lei [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan Shandong 250061 (China); School of Materials Science and Engineering, Shandong University, Jinan Shandong 250061 (China)

    2012-12-15

    The variations of microstructure, mechanical properties and electrical resistivity of 690 MPa grade low carbon bainitic steel tempered at different temperatures were investigated with Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and double-arm Bridge. The results show that the appearance of granular bainite, decomposition of retained austenite, variations of dislocation density and solid solution of microalloying elements are the main reasons for variations of mechanical properties and electrical resistivity. Electrical resistivity reflects the solution content of microalloying elements and variations of dislocation density, which can be used as a fast and effective way to analyze the microstructure of materials.

  20. The functionally graded sintered steel WC-Co-NbC matrix

    Energy Technology Data Exchange (ETDEWEB)

    Santos, A.A.A.; Silva Junior, J.F. [Universidade Federal do Rio Grande do Norte (UFRN), Natal (Brazil)

    2009-07-01

    Full text: The high speed steels are used for machining, including cutting tools at high speeds because their wear resistance, high temperature properties and excellent hardness. They are ferrous based alloys of the Fe-C-X component system where X represents a group of elements comprising Cr, W or Mo, V and Co. The aim of this work was to study the feasibility of powder metallurgy technique to develop functionally graded alloy material added by WC, Co and NbC. The morphology of the composite powders and sintered MMC were characterized by scanning electron microscopy and XRD measurements. (author)

  1. Development of a non-destructive method to identify different grades of stainless steel

    International Nuclear Information System (INIS)

    Meor Yusoff Meor Sulaiman

    2003-01-01

    One of the non-destructive methods used for the identification and verification of metals is by the energy-dispersive X-ray fluorescence (EDXRF) technique. EDXRF analysis provides several important advantages such as simultaneous determination of the elements present, enable to analyse a very wide concentration range, fast analysis with no sample preparation. The paper shows how this technique is developed and applied in the identification and verification of different grades of stainless steels. Comparison of the results for certified reference standards obtained from this analysis and that of its certified value shows very small differences between them. (Author)

  2. Development of a non-destructive method to identify different grades of stainless steel

    International Nuclear Information System (INIS)

    Meor Yusoff Meor Sulaiman

    2004-01-01

    One of the non-destructive methods used for the identification and verification of metals is by the energy-dispersive x-ray fluorescence (EDXRF) technique. EDXRF analysis provides several important advantages such as simultaneous determination of the elements present, enable to analyze a very wide concentration range, fast analysis with no tedious sample preparation. The paper shows how this technique is developed and applied in the identification and verification of different grades of stainless steels. Comparison of the results obtained from this analysis with certified reference standards show very small differences between them. (Author)

  3. Understanding and Predicting Effect of Sodium Exposure on Microstructure of Grade 91 Steel

    Energy Technology Data Exchange (ETDEWEB)

    Li, Meimei [Argonne National Lab. (ANL), Argonne, IL (United States); Natesan, K. [Argonne National Lab. (ANL), Argonne, IL (United States); Chen, Wei-Ying [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-08-01

    This report provides an update on the understanding of the effect of sodium exposures on microstructure and tensile properties of Grade 91 (G91) steel in support of the design and operation of G91 components in sodium-cooled fast reactors (SFRs). The report is a Level 3 deliverable in FY17 (M3AT-17AN1602018), under the Work Package AT-17AN160201, “SFR Materials Testing” performed by the Argonne National Laboratory (ANL), as part of the Advanced Reactor Technologies Program.

  4. Study on creep behavior of Grade 91 heat-resistant steel using theta projection method

    Science.gov (United States)

    Ren, Facai; Tang, Xiaoying

    2017-10-01

    Creep behavior of Grade 91 heat-resistant steel used for steam cooler was characterized using the theta projection method. Creep tests were conducted at the temperature of 923K under the stress ranging from 100-150MPa. Based on the creep curve results, four theta parameters were established using a nonlinear least square fitting method. Four theta parameters showed a good linearity as a function of stress. The predicted curves coincided well with the experimental data and creep curves were also modeled to the low stress level of 60MPa.

  5. Comparative study in the induced corrosion by sulfate reducing microorganisms, in a stainless steel 304L sensitized and a carbon steel API X65

    International Nuclear Information System (INIS)

    Diaz S, A.; Gonzalez F, E.; Arganis J, C.; Luna C, P.; Carapia M, L.

    2004-01-01

    In spite of the operational experience related with the presence of the phenomenon of microbiological corrosion (MIC) in industrial components, it was not but until the decade of the 80 s when the nuclear industry recognized its influence in some systems of Nuclear Generating Power plants. At the moment, diverse studies that have tried to explain the generation mechanism of this phenomenon exist; however, they are even important queries that to solve, especially those related with the particularities of the affected metallic substrates. Presently work, the electrochemical behavior of samples of stainless steel AISI 304L sensitized is evaluated and the carbon steel APIX65, before the action of sulfate reducing microorganisms low the same experimental conditions; found that for the APIX65 the presence of this type of bacteria promoted the formation of a stable biofilm that allowed the maintenance of the microorganisms that damaged the material in isolated places where stings were generated; while in the AISI 304L, it was not detected damage associated to the inoculated media. The techniques of Resistance to the Polarization and Tafel Extrapolation, allowed the calculation of the speed of uniform corrosion, parameter that doesn't seem to be influenced by the presence of the microorganisms; while that noise electrochemical it distinguished in real time, the effect of the sulfate reducing in the steel APIX65. (Author)

  6. Compositional homogeneity in a medical-grade stainless steel sintered with a Mn–Si additive

    International Nuclear Information System (INIS)

    Salahinejad, E.; Hadianfard, M.J.; Ghaffari, M.; Mashhadi, Sh. Bagheri; Okyay, A.K.

    2012-01-01

    In this paper, chemical composition uniformity in amorphous/nanocrystallization medical-grade stainless steel (ASTM ID: F2581) sintered with a Mn–Si additive was studied via scanning electron microscopy, energy dispersive X-ray spectroscopy, and transmission electron microscopy. The results show that as a result of sintering at 1000 °C, no dissociation of Mn–Si additive particles embedded in the stainless steel matrix occurs. In contrast, sintering at 1050 °C develops a relatively homogeneous microstructure from the chemical composition viewpoint. The aforementioned phenomena are explained by liquation of the Mn–Si eutectic additive, thereby wetting of the main powder particles, penetrating into the particle contacts and pore zones via capillary forces, and providing a path of high diffusivity. - Highlights: ► Local chemical composition in a sintered stainless steel was studied. ► Due to sintering at 1000 °C, no dissociation of additive particles occurs. ► Sintering at 1050 °C provides a uniform chemical composition.

  7. Characterization of carbon ion implantation induced graded microstructure and phase transformation in stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Kai; Wang, Yibo [Shanghai Key laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Li, Zhuguo, E-mail: lizg@sjtu.edu.cn [Shanghai Key laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Chu, Paul K. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)

    2015-08-15

    Austenitic stainless steel 316L is ion implanted by carbon with implantation fluences of 1.2 × 10{sup 17} ions-cm{sup −} {sup 2}, 2.4 × 10{sup 17} ions-cm{sup −} {sup 2}, and 4.8 × 10{sup 17} ions-cm{sup −} {sup 2}. The ion implantation induced graded microstructure and phase transformation in stainless steel is investigated by X-ray diffraction, X-ray photoelectron spectroscopy and high resolution transmission electron microscopy. The corrosion resistance is evaluated by potentiodynamic test. It is found that the initial phase is austenite with a small amount of ferrite. After low fluence carbon ion implantation, an amorphous layer and ferrite phase enriched region underneath are formed. Nanophase particles precipitate from the amorphous layer due to energy minimization and irradiation at larger ion implantation fluence. The morphology of the precipitated nanophase particles changes from circular to dumbbell-like with increasing implantation fluence. The corrosion resistance of stainless steel is enhanced by the formation of amorphous layer and graphitic solid state carbon after carbon ion implantation. - Highlights: • Carbon implantation leads to phase transformation from austenite to ferrite. • The passive film on SS316L becomes thinner after carbon ion implantation. • An amorphous layer is formed by carbon ion implantation. • Nanophase precipitate from amorphous layer at higher ion implantation fluence. • Corrosion resistance of SS316L is improved by carbon implantation.

  8. Calculation of α/γ equilibria in SA508 grade 3 steels for intercritical heat treatment

    International Nuclear Information System (INIS)

    Lee, B.J.; Kim, H.D.; Hong, J.H.

    1998-01-01

    An attempt has been made to suggest an optimum temperature for intercritical heat treatment of an SA508 grade 3 steel for nuclear pressure vessels, based on thermodynamic calculation of the α/γ phase equilibria. A thermodynamic database constructed for the Fe-Mn-Ni-Mo-Cr-Si-V-Al-C-N ten-component system and an empirical criterion that the amount of reformed austenite should be around 40 pct were used for thermodynamic calculation and derivation of the optimum heat-treatment temperature, respectively. The calculated optimum temperature, 720 C, was in good agreement with an experimentally determined temperature of 725 C obtained through an independent experimental investigation of the same steel. The agreement between the calculated and measured fraction of reformed austenite during the intercritical heat treatment was also confirmed. Based on the agreement between calculation and experiment, it could be concluded that thermodynamic calculations can be successfully applied to the materials and/or process design as an additive tool to the already established technology, and that the currently constructed thermodynamic database for steel systems shows an accuracy that makes such applications possible

  9. Establishment of quality system program for the manufacture of nuclear grade steels

    International Nuclear Information System (INIS)

    Saito, Toru

    1978-01-01

    Recently, the pressure vessels employed in the fields of nuclear power generation, petroleum refining, and chemical industry tend to be large size and high performance, therefore thick steel plates and forgings of high quality are demanded, and the establishment and maintenance of strict quality assurance system for material production are required. In Mizushima Works, Kawasaki Steel Corp., the installations for large forgings and thick plates were constructed from 1969 to 1976, and the researches on the development of production techniques were forwarded in parallel. A Quality System Certificate (Material) has been granted to Mizushima Works on March 11, 1977, by the American Society of Mechanical Engineers for the manufacture of steel plates and forgings of nuclear grade. The quality system manual as the basis of quality assurance activities, the organization for quality assurance, its responsibility and authority, the discrimination of materials, the control of manufacturing processes, the qualification of workers in charge of nondestructive test, welding, heat treatment and others, the management of tests and inspections, the management of products with faults and repairing measures, and internal supervisory system are explained. The wide use of computers is novel in the field of quality system program. (Kako, I.)

  10. Correlation between aging grade of T91 steel and spectral characteristics of the laser-induced plasma

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jun [Power Electric College in South China University of Technology, Guangzhou 510640 (China); Lu, Jidong, E-mail: jdlu@scut.edu.cn [Power Electric College in South China University of Technology, Guangzhou 510640 (China); Dai, Yuan [Electric Power Research Institute of Guangdong Power Grid Company, Guangzhou 510080 (China); Dong, Meirong [Power Electric College in South China University of Technology, Guangzhou 510640 (China); Zhong, Wanli [Electric Power Research Institute of Guangdong Power Grid Company, Guangzhou 510080 (China); Yao, Shunchun [Power Electric College in South China University of Technology, Guangzhou 510640 (China)

    2015-08-15

    Highlights: • Laser-induced breakdown spectroscopy (LIBS) was first employed to estimate the aging grade of T91 steel. • The differences from the ionic-to-atomic ratio of the same elements indicated that the grade is the reason to cause the difference of the plasma characteristics. • Good unique value correlations between the peak intensity ratio of CrI/FeI, MoI/FeI and the aging grade were found. • The research indicates that LIBS technique is a potential way to estimate the aging grade of T91 steel. - Abstract: T91 steel with favorable mechanical performance has become the representative heat-resistant steel used as heat exchange surfaces in supercritical and ultra-supercritical boilers. The organizational structure and mechanical properties change during the service period, called material aging, which affects the service life and the equipment safety. To develop a fast and easy aging predictive technique of heat exchange metal surfaces, laser-induced breakdown spectroscopy (LIBS) was applied to investigate the plasma characteristics of T91 steel specimens with different aging grades. The metallographic structure, mechanical properties and spectral characteristics of the specimens were analyzed. Then, the correlations between the spectral characteristics and the aging grade were established. The analysis results show that the martensite substructure disappears, and the dimension of the carbide particles among the crystal lattices increases with aging. At the same time, the hardness of the samples gradually decreases. The peak intensities of both the matrix and the alloying element increases then decreases with aging, owing to the change of the metallography structure and mechanical properties. Furthermore, good unique value correlations between the intensity ratio of CrI/FeI, MoI/FeI and the aging grade are found. This demonstrates that LIBS is a possible new way to estimate the aging grade of metal materials.

  11. Correlation between aging grade of T91 steel and spectral characteristics of the laser-induced plasma

    International Nuclear Information System (INIS)

    Li, Jun; Lu, Jidong; Dai, Yuan; Dong, Meirong; Zhong, Wanli; Yao, Shunchun

    2015-01-01

    Highlights: • Laser-induced breakdown spectroscopy (LIBS) was first employed to estimate the aging grade of T91 steel. • The differences from the ionic-to-atomic ratio of the same elements indicated that the grade is the reason to cause the difference of the plasma characteristics. • Good unique value correlations between the peak intensity ratio of CrI/FeI, MoI/FeI and the aging grade were found. • The research indicates that LIBS technique is a potential way to estimate the aging grade of T91 steel. - Abstract: T91 steel with favorable mechanical performance has become the representative heat-resistant steel used as heat exchange surfaces in supercritical and ultra-supercritical boilers. The organizational structure and mechanical properties change during the service period, called material aging, which affects the service life and the equipment safety. To develop a fast and easy aging predictive technique of heat exchange metal surfaces, laser-induced breakdown spectroscopy (LIBS) was applied to investigate the plasma characteristics of T91 steel specimens with different aging grades. The metallographic structure, mechanical properties and spectral characteristics of the specimens were analyzed. Then, the correlations between the spectral characteristics and the aging grade were established. The analysis results show that the martensite substructure disappears, and the dimension of the carbide particles among the crystal lattices increases with aging. At the same time, the hardness of the samples gradually decreases. The peak intensities of both the matrix and the alloying element increases then decreases with aging, owing to the change of the metallography structure and mechanical properties. Furthermore, good unique value correlations between the intensity ratio of CrI/FeI, MoI/FeI and the aging grade are found. This demonstrates that LIBS is a possible new way to estimate the aging grade of metal materials

  12. Suitability of the double Langevin function for description of anhysteretic magnetization curves in NO and GO electrical steel grades

    Directory of Open Access Journals (Sweden)

    Simon Steentjes

    2017-05-01

    Full Text Available This paper compares the match obtained using the classical Langevin function, the tanh function as well as a recently by the authors proposed double Langevin function with the measured anhysteretic magnetization curve of three different non-oriented electrical steel grades and one grain-oriented grade. Two standard non-oriented grades and a high-silicon grade (Si content of 6.5% made by CVD are analyzed. An excellent match is obtained using the double Langevin function, whereas the classical solutions are less appropriate. Thereby, problems such as those due to propagation of approximation errors observed in hysteresis modeling can be bypassed.

  13. Influence of heat input and radius to pipe thickness ratio on the residual stresses in circumferential arc welded pipes of API X46 steels

    International Nuclear Information System (INIS)

    Hemmatzadeh, Majid; Moshayedi, Hessamoddin; Sattari-Far, Iradj

    2017-01-01

    The present work aims to study residual stresses caused by circumferentially welding of two similar API X46 steel pipes by means of finite element modeling. Considering the metallurgical phase transformations and through thermal-mechanical uncoupled analysis, the 3D modeling was carried out by SYSWELD software. Materialistic thermal and mechanical properties of all phases were defined in terms of temperature as well as phase transformation properties. Residual stress was measured through hole-drilling method. The obtained results were used to verify the finite element model. By means of full factorial experiment designing method, effects of heat input and radius to pipe thickness ratio on maximum values of hoop and axial residual stresses were investigated. The effect of each factor was studied in 3 levels and by 9 experiments. Results of statistical analysis revealed that increase in heat input and radius-thickness ratio would lead to higher values of maximum hoop and axial residual stresses. However, interactions of high level of heat input and a low level of radius-thickness ratio increased inter-pass temperature and consequently caused a sudden raise in maximum values of residual stresses. - Highlights: • A FEM model was developed to simulate welding considering phase transformations. • The obtained residual stresses were validated by experiments. • Effect of heat input and radius-to-thickness ratio on residual stress were investigated. • Increasing heat input for 100% caused increasing hoop and axial residual stress until 200%. • Interaction of high heat input and low R/t causes a sudden increase in axial residual stresses.

  14. Effect of Thermomechanical Processing and Crystallographic Orientation on the Corrosion Behavior of API 5L X70 Pipeline Steel

    Science.gov (United States)

    Ohaeri, Enyinnaya; Omale, Joseph; Eduok, Ubong; Szpunar, Jerzy

    2018-04-01

    This work presents the electrochemical response of X70 pipeline steel substrates thermomechanically processed at different conditions. The WE sample was hot rolled at a temperature range of 850 °C to 805 °C and cooled at a rate of 42.75 °C/s. Another sample WD was hot rolled from 880 °C to 815 °C and cooled at a faster rate of 51.5 °C/s. Corrosion tests were conducted electrochemically by potentiodynamic polarization in hydrogen-charged and non-hydrogen-charged environments. A lower corrosion rate was measured with hydrogen charging due to the rapid formation of corrosion product film on pipeline substrate, but WE specimen emerged as the most susceptible to corrosion with and without hydrogen charging. Variations in thermomechanical rolling conditions influenced grain orientation, protective film properties, corrosion, and cracking behavior on both specimens. Cracks were seen in both specimens after hydrogen charging, but specimen WE experienced a more intense deterioration of protective corrosion product film and subsequent cracking. A large part of specimen WD retained its protective corrosion product film after the polarization test, and sites where spalling occurred resulted in pitting with less cracking. Despite weak crystallographic texture noticed in both specimens, WD showed a higher intensity of corrosion-resistant 111||ND-oriented grains, while WE showed a more random distribution of 111||ND-, 011||ND-, and 001||ND-oriented grains with a lower intensity.

  15. The effect of processing parameters on the dynamic recrystallisation behaviour of API-X70 pipeline steel

    International Nuclear Information System (INIS)

    Al Shahrani, Abdullah; Yazdipour, Nima; Dehghan-Manshadi, Ali; Gazder, Azdiar A.; Cayron, Cyril; Pereloma, Elena V.

    2013-01-01

    The effect of deformation temperature and strain rate on the dynamic recrystallisation (DRX) behaviour of X70 pipeline steel was investigated. DRX parameters such as the critical and peak stresses and strains as well as the deformation activation energy were determined in the temperature range between 925 °C and 1125 °C for strain rates of 0.1, 1 and 5 s −1 . The relationship between the peak stresses and strains with the Zener–Hollomon parameter was determined. The dynamically recrystallised volume fraction was computed as a function of the different temperatures and strain rates. The APRGE software was applied for the first time on electron back-scattering diffraction data of dynamically recrystallised microstructures in order to reconstruct the prior austenite from the as-quenched martensite phase. The dynamically recrystallised flow stress curves and microstructure were also predicted using cellular automata modelling. The results show an earlier onset of DRX with a decrease in strain rate or an increase in deformation temperature. The dynamically recrystallised grain size is also found to decrease with an increase in strain rate and a lowering of deformation temperature

  16. Effect of Thermomechanical Processing and Crystallographic Orientation on the Corrosion Behavior of API 5L X70 Pipeline Steel

    Science.gov (United States)

    Ohaeri, Enyinnaya; Omale, Joseph; Eduok, Ubong; Szpunar, Jerzy

    2018-06-01

    This work presents the electrochemical response of X70 pipeline steel substrates thermomechanically processed at different conditions. The WE sample was hot rolled at a temperature range of 850 °C to 805 °C and cooled at a rate of 42.75 °C/s. Another sample WD was hot rolled from 880 °C to 815 °C and cooled at a faster rate of 51.5 °C/s. Corrosion tests were conducted electrochemically by potentiodynamic polarization in hydrogen-charged and non-hydrogen-charged environments. A lower corrosion rate was measured with hydrogen charging due to the rapid formation of corrosion product film on pipeline substrate, but WE specimen emerged as the most susceptible to corrosion with and without hydrogen charging. Variations in thermomechanical rolling conditions influenced grain orientation, protective film properties, corrosion, and cracking behavior on both specimens. Cracks were seen in both specimens after hydrogen charging, but specimen WE experienced a more intense deterioration of protective corrosion product film and subsequent cracking. A large part of specimen WD retained its protective corrosion product film after the polarization test, and sites where spalling occurred resulted in pitting with less cracking. Despite weak crystallographic texture noticed in both specimens, WD showed a higher intensity of corrosion-resistant 111|| ND-oriented grains, while WE showed a more random distribution of 111|| ND-, 011|| ND-, and 001|| ND-oriented grains with a lower intensity.

  17. Development and Technology of Large Thickness TMCP Steel Plate with 390MPA Grade Used for Engineering Machinery

    Science.gov (United States)

    Wang, Xiaoshu; Zhang, Zhijun; Zhang, Peng

    Recently, with the rapid upgrading of the equipment in the steel Corp, the rolling technology of TMCP has been rapidly developed and widely applied. A large amount of steel plate has been produced by using the TMCP technology. The TMCP processes have been used more and more widely and replaced the heat treatment technology of normalizing, quenching and tempering heat process. In this paper, low financial input is considered in steel plate production and the composition of the steel has been designed with low C component, a limited alloy element of the Nb, and certain amounts of Mn element. During the continuous casting process, the size of the continuous casting slab section is 300 mm × 2400 mm. The rolling technology of TMCP is controlled at a lower rolling and red temperature to control the transformation of the microstructure. Four different rolling treatments are chosen to test its effects on the 390MPa grade low carbon steel of bainitic microstructure and properties. This test manages to produce a proper steel plate fulfilling the standard mechanical properties. Specifically, low carbon bainite is observed in the microstructure of the steel plate and the maximum thickness of steel plate under this TMCP technology is up to 80mm. The mechanical property of the steel plate is excellent and the KV2 at -40 °C performs more than 200 J. Moreover, the production costs are greatly reduced when the steel plate is produced by this TMCP technology when replacing the current production process of quenching and tempering. The low cost steel plate could well meet the requirements of producing engineering machinery in the steel market.

  18. Corrosion of API 5L B and X52 in crude oil/water/gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Perdomo, J J; Gonzalez, J J; Viloria, A; De Veer, H; De Abreu, Y

    2000-02-01

    Laboratory and field tests were conducted to evaluate the corrosion behavior of API 5L grade B and X52 steels using Furrial's crude oil in the presence of water and gas containing carbon dioxide (CO{sub 2}) and hydrogen sulfide (H{sub 2}S). The results suggest that the corrosiveness of this crude oil/water/gas mixture is not detrimental to either steel. However, pitting corrosion was observed. The low general corrosion rates measured were attributed to the natural inhibiting properties of the crude oil.

  19. Corrosion of API 5L B and X52 in crude oil/water/gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Perdomo, J.J.; Gonzalez, J.J.; Viloria, A.; De Veer, H.; De Abreu, Y.

    2000-02-01

    Laboratory and field tests were conducted to evaluate the corrosion behavior of API 5L grade B and X52 steels using Furrial's crude oil in the presence of water and gas containing carbon dioxide (CO{sub 2}) and hydrogen sulfide (H{sub 2}S). The results suggest that the corrosiveness of this crude oil/water/gas mixture is not detrimental to either steel. However, pitting corrosion was observed. The low general corrosion rates measured were attributed to the natural inhibiting properties of the crude oil.

  20. The Prediction of the Mechanical Properties for Dual-Phase High Strength Steel Grades Based on Microstructure Characteristics

    Directory of Open Access Journals (Sweden)

    Emil Evin

    2018-04-01

    Full Text Available The decrease of emissions from vehicle operation is connected mainly to the reduction of the car’s body weight. The high strength and good formability of the dual phase steel grades predetermine these to be used in the structural parts of the car’s body safety zones. The plastic properties of dual phase steel grades are determined by the ferrite matrix while the strength properties are improved by the volume and distribution of martensite. The aim of this paper is to describe the relationship between the mechanical properties and the parameters of structure and substructure. The heat treatment of low carbon steel X60, low alloyed steel S460MC, and dual phase steel DP600 allowed for them to reach states with a wide range of volume fractions of secondary phases and grain size. The mechanical properties were identified by a tensile test, volume fraction of secondary phases, and grain size were measured by image analysis. It was found that by increasing the annealing temperature, the volume fraction of the secondary phase increased, and the ferrite grains were refined. Regression analysis was used to find out the equations for predicting mechanical properties based on the volume fraction of the secondary phase and grain size, following the annealing temperature. The hardening mechanism of the dual phase steel grades for the states they reached was described by the relationship between the strain-hardening exponent and the density of dislocations. This allows for the designing of dual phase steel grades that are “tailored” to the needs of the automotive industry customers.

  1. Heat treatment evaluation of steel ASTM A-131 grade A by X-Ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira Junior, Francisco; Feio, Luciana Gaspar; Costa, Ednelson Silva; Rodrigues, Lino Alberto Soares; Braga, Eduardo Magalhaes, E-mail: juniorferrer93@gmail.com [Universidade Federal do Pará (UFPA), Belém, PA (Brazil)

    2016-07-01

    Full text: This study evaluates the residual stress of naval steel ASTM A-131 grade A before and after heat treatment. Residual stresses were determined by the technique of X-ray diffraction (XRD). Before heat treatment the residual stress measurements were made at 36 (thirty six) points distributed in a specimen with dimensions of 400 mm long, 200 mm wide and 95 mm thick, then the plate under analysis was brought to the oven for the implementation of heat treatment. To check the performance of the heat treatment, the plate was again subjected to XRD measurements of the same points previously measured in order to compare the residual stresses. As result, there was a reduction of residual stresses with the application of heat treatment. References: [1] COLPAERT, H. Metalografia dos Produtos Siderurgicos Comuns. 4 Edição. Editora Blucher. Saõ Paulo, SP, 2008. [2] HILL, R. Princípios de Metalurgia Física, 1992. (author)

  2. The Properties of Arc-Sprayed Aluminum Coatings on Armor-Grade Steel

    Directory of Open Access Journals (Sweden)

    Marcin Adamiak

    2018-02-01

    Full Text Available This article presents the results of an examination of the properties of arc-sprayed aluminum on alloyed armor-grade steel. Thermal arc spraying was conducted with a EuTronic Arc Spray 4 wire arc sprayer. Aluminum wire 1.6 mm in diameter was used to produce dense, abrasion- and erosion-resistant coatings approx. 1.0 mm thick with and without nickel/5% aluminum-buffered subcoating. Aluminum coatings were characterized in accordance with ASTM G 65-00 abrasion resistance test, ASTM G 76-95 erosion resistance tests, ASTM C 633-01 adhesion strength, HV0.1 hardness tests and metallographic analyses. Results demonstrate properties of arc-sprayed aluminum and aluminum-nickel material coatings that are especially promising in industrial applications where erosion-, abrasion- and corrosion-resistant coating properties are required.

  3. Microstructure-property relationships and constitutive response of plastically graded case hardened steels

    Science.gov (United States)

    Klecka, Michael A.

    Case hardened materials, popularly used in many demanding engineering applications such as bearings, gears, and wear/impact surfaces, have high surface hardness and a gradient in material properties (hardness, yield strength, etc.) as a function of depth; therefore, they behave as plastically graded materials. In the current study, two different commercially available case carburized steels along with two through hardened steels are characterized to obtain relationships among the volume fraction of subsurface carbides, indentation hardness, elastic modulus, and yield strength as a function of depth. A variety of methods including microindentation, nanoindentation, ultrasonic measurements, compression testing, rule of mixtures, and upper and lower bound models are used to determine the relationships for elastic modulus and compare the experimental results with model predictions. In addition, the morphology, composition, and properties of the carbide particles are also determined. The gradient in hardness with depth in graded materials is commonly determined using microindentation on the cross-section of the material which contains the gradation in microstructure or composition. In the current study, a novel method is proposed to predict the hardness gradient profile using solely surface indentations at a range of loads. The method does not require the graded material to be sectioned, and has practical utility in the surface heat-treatment industry. For a material with a decreasing gradient in hardness, higher indent loads result in a lower measured hardness due to the influence of the softer subsurface layers. A power-law model is presented which relates the measured surface indentation hardness under increasing load to the subsurface gradient in hardness. A coordinated experimental and numerical study is presented to extract the constitutive response of graded materials, utilizing relationships between hardness, plastic deformation, and strain hardening response

  4. Microstructural and Mechanical Characterization of Electron Beam Welded Joints of High Strength S960QL and Weldox 1300 Steel Grades

    Directory of Open Access Journals (Sweden)

    Błacha S.

    2017-06-01

    Full Text Available The paper shows the results of metallographic examination and mechanical properties of electron beam welded joints of quenched and tempered S960QL and Weldox 1300 steel grades. The aim of this study was to examine the feasibility of producing good quality electron beam welded joints without filler material.

  5. Effects of the normalizing time and temperature on the impact properties of ASTM A-516 grade 70 steel

    International Nuclear Information System (INIS)

    Carneiro, T.; Cescon, T.

    1982-01-01

    The influence of normalizing time and temperature, as well as the plate thickness, on the impact properties of ASTM A-516 grade 70 steel, is studied. Results show that different normalizing conditions may lead to equivalent microstructure with different impact properties. Normalizing conditions that cause low cooling rate in the critical zone exhibit banded microstructure with inferior impact properties. (Author) [pt

  6. Braze alloy process and strength characterization studies for 18 nickel grade 200 maraging steel with application to wind tunnel models

    Science.gov (United States)

    Bradshaw, James F.; Sandefur, Paul G., Jr.; Young, Clarence P., Jr.

    1991-01-01

    A comprehensive study of braze alloy selection process and strength characterization with application to wind tunnel models is presented. The applications for this study include the installation of stainless steel pressure tubing in model airfoil sections make of 18 Ni 200 grade maraging steel and the joining of wing structural components by brazing. Acceptable braze alloys for these applications are identified along with process, thermal braze cycle data, and thermal management procedures. Shear specimens are used to evaluate comparative shear strength properties for the various alloys at both room and cryogenic (-300 F) temperatures and include the effects of electroless nickel plating. Nickel plating was found to significantly enhance both the wetability and strength properties for the various braze alloys studied. The data are provided for use in selecting braze alloys for use with 18 Ni grade 200 steel in the design of wind tunnel models to be tested in an ambient or cryogenic environment.

  7. Effect of residual Al content on microstructure and mechanical properties of Grade B+Steel for castings for locomotives

    Directory of Open Access Journals (Sweden)

    Wang Kaifeng

    2013-11-01

    Full Text Available The bogie made of Grade B+ steel is one of the most important parts of heavy haul trains. Some accidents were found to be the result of fracture failure of the bogies. It is very important to find the reason why the fracture failure occurred. Because Al was added for the final deoxidation during the smelting process of the Grade B+Steel, residual Al existed to some extent in the castings. High residual Al content in the bogie casting was presumed to be the reason for the fracture. In this work, the influence of residual Al content in the range of 0.015wt.% to 0.3wt.% on the microstructure and mechanical properties of the Grade B+ Steel was studied. The experimental results showed that when the residual Al content is between 0.02wt.% and 0.20wt.%, the mechanical properties of the steel meet the requirements of technical specification for heavy haul train parts, and the fracture is typical plastic fractures. If the residual Al content is less than 0.02wt.%, the microstructures are coarse, and the mechanical properties can not meet the demand of bogie steel castings. When the residual Al content is more than 0.2wt.%, the elongation, reduction of area, and low-temperature impact energy markedly deteriorate. The fracture mode then changes from plastic fracture to cleavage brittle fracture. Therefore, the amount of Al addition for the final deoxidation during the smelting process must be strictly controlled. The optimum addition amount needs to be controlled within the range of 0.02wt.% to 0.20wt.% for the Grade B+Steel.

  8. Microstructural Characterization and Mechanical Properties of Electron Beam Welded Joint of High Strength Steel Grade S690QL

    Directory of Open Access Journals (Sweden)

    Błacha S.

    2016-06-01

    Full Text Available In the paper the results of metallographic examination and mechanical properties of electron beam welded joint of quenched and tempered steel grade S690QL are presented. Metallographic examination revealed that the concentrated electron beam significantly affect the changes of microstructure in the steel. Parent material as a delivered condition (quenched and tempered had a bainitic-martensitic microstructure at hardness about 290 HV0.5. After welding, the microstructure of heat affected zone is composed mainly of martensite (in the vicinity of the fusion line of hardness 420 HV0.5. It should be noted, however, that the microstructure of steel in the heat affected zone varies with the distance from the fusion line. The observed microstructural changes were in accordance with the CCT-S transformation diagram for the examined steel.

  9. Evaluation of the susceptibility to pitting corrosion of steel api 5L x42 exposed to solutions containing chloride ions and CO{sub 2} by electrochemical noise measurements; Evaluacion de la susceptibilidad a la corrosion por picado del acero api 5l x42 expuesto a un ambiente con cloruros y CO{sub 2} mediante la tecnica de ruido electroquimico

    Energy Technology Data Exchange (ETDEWEB)

    Pena-Ballesteros, D.; Rodriguez-Vanegas, N.; Anteliz, C.; Sarmiento Klapper, H.

    2011-07-01

    The concentration of chloride ions and the partial pressure of CO{sub 2} play an important role in the degradation of low-carbon steels used for the construction of pipelines in oil and gas industry. In order to evaluate the susceptibility of carbon steel API 5L X42 to pitting corrosion electrochemical noise and linear polarization resistance measurements were carried out in aqueous solutions containing chloride ions and CO{sub 2}. The concentration of chloride ions was varied between, 10000 and 18000 ppm, and the CO{sub 2} partial pressure between 10 psi and 18 psi. Experimental results pointed out that the formation of protective layer, consisting mainly of FeCO{sub 3}, depends on the partial pressure of CO{sub 2} in the system. Nevertheless, the stability of this layer was considerably affected by increasing the concentration of chloride ions causing that localized corrosion has taken place in some areas of the surface of API 5L X42, which were detected by electrochemical noise technique. (Author) 10 refs.

  10. Investigation of the Microstructural, Mechanical and Corrosion Properties of Grade A Ship Steel-Duplex Stainless Steel Composites Produced via Explosive Welding

    Science.gov (United States)

    Kaya, Yakup; Kahraman, Nizamettin; Durgutlu, Ahmet; Gülenç, Behçet

    2017-08-01

    Grade A ship-building steel-AISI 2304 duplex stainless steel composite plates were manufactured via explosive welding. The AISI 2304 plates were used to clad the Grade A plates. Optical microscopy studies were conducted on the joining interface for characterization of the manufactured composite plates. Notch impact, tensile-shear, microhardness, bending and twisting tests were carried out to determine the mechanical properties of the composites. In addition, the surfaces of fractured samples were examined by scanning electron microscopy (SEM), and neutral salt spray (NSS) and potentiodynamic polarization tests were performed to examine corrosion behavior. Near the explosion zone, the interface was completely flat, but became wavy as the distance from the explosion zone increased. The notch impact tests indicated that the impact strength of the composites decreased with increasing distance from the explosion zone. The SEM studies detected brittle behavior below the impact transition temperature and ductile behavior above this temperature. Microhardness tests revealed that the hardness values increased with increasing distance from the explosion zone and mechanical tests showed that no visible cracking or separation had occurred on the joining interface. The NSS and potentiodynamic polarization tests determined that the AISI 2304 exhibited higher corrosion resistance than the Grade A steel.

  11. An approach to optimization of the choice of boiler steel grades as to a mixed-integer programming problem

    International Nuclear Information System (INIS)

    Kler, Alexandr M.; Potanina, Yulia M.

    2017-01-01

    One of the ways to enhance the energy efficiency of thermal power plants is to increase thermodynamic parameters of steam. A sufficient level of reliability and longevity can be provided by the application of advanced construction materials (in particular, high-alloy steel can be used to manufacture the most loaded heating surfaces of a boiler unit). A rational choice of technical and economic parameters of energy plants as the most complex technical systems should be made using the methods of mathematical modeling and optimization. The paper considers an original approach to an economically sound optimal choice of steel grade to manufacture heating surfaces for boiler units. A case study of optimization of the discrete-continuous parameters of an energy unit operating at ultra-supercritical steam parameters, in combination with construction of a variant selection tree is presented. - Highlights: • A case study on optimization of an ultra-supercritical power plant is demonstrated. • Optimization is based on the minimization of electricity price. • An approach is proposed to optimize the selection of boiler steel grades. • The approach is based on the construction of a variant tree. • The selection of steel grades for a boiler unit is shown.

  12. Drug Interaction API

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Interaction API is a web service for accessing drug-drug interactions. No license is needed to use the Interaction API. Currently, the API uses DrugBank for its...

  13. Investigations on diffusion-controlled transformations in creep resistant steels and graded cemented carbides

    International Nuclear Information System (INIS)

    Prat Borquez, Orlando

    2011-01-01

    The objective of this work was to simulate diffusion-controlled transformations on engineering alloys designed by the author and his colleagues. The main challenge of the work is to adapt the existing DICTRA models to the experimental processing and working conditions investigated, as well as to find the adequate boundary conditions for the description of the diffusion-controlled transformations governing the microstructure formation and evolution, in order to obtain reliable simulation results. The simulations were compared with experimental results of the microstructure evolution by scanning electron microscopy and scanning transmission electron microscopy (STEM). Two groups of materials were investigated. The first group was 9-12% Cr heat resistant alloys. These alloys are particularly interesting because the microstructure evolves during working conditions. Different compositions were designed in order to form different kinds and amounts of precipitates. For the designed 9-12% Cr creep steels the coarsening of MX and M 23 C 6 particles was modeled by applying the coarsening model implemented in DICTRA. The cell method of DICTRA was applied to investigate the kinetics of the Laves phase growth on 9-12% Cr alloys. The particular objectives of these investigations were: a) to determine the coarsening rate of precipitates, b) to investigate the influence of alloying element on the growth rate of the Laves phase, c) to determine the influence of the M 23 C 6 formation on the growth kinetics of the Laves phase, d) to determine the growth mechanism at the interface of the Laves phase (i.e. up-hill diffusion), e) to investigate the effect of the cell size on the simulation kinetics of Laves phase. The second group of materials was cemented carbides. They are used as cutting tools or wear parts in the automotive, aircraft and mining industry among others. The wear performance of cemented carbides (hardmetals and cermets) can be largely improved by applying wear

  14. Assessment of the integrity of ferritic-austenitic dissimilar weld joints of different grades of Cr-Mo ferritic steels

    Energy Technology Data Exchange (ETDEWEB)

    Laha, K.; Chandravathi, K.S.; Parameswaran, P.; Goyal, Sunil; Mathew, M.D. [Indira Gandhi Centre for Atomic Research, Kalpakkam (India). Metallurgy and Materials Group

    2010-07-01

    Integrity of the 2.25 Cr-1Mo / Alloy 800, 9Cr-1Mo / Alloy 800 and 9Cr-1Mo-VNb / Alloy 800 ferritic-austenitic dissimilar joints, fusion welded employing Inconel 182 electrode, has been assessed under creep conditions at 823 K. The dissimilar weld joints displayed lower creep rupture strength than their respective ferritic steel base metals. The strength reduction was more for 2.25Cr-1Mo steel joint and least for 9Cr-1Mo steel joint. The failure location in the joints was found to shift from the ferritic steel base metal to the intercritical region of heat-affected zone (HAZ) in ferritic steel (type IV cracking) with decrease in stress. At still lower stresses the failure occurred at the ferritic / austenitic weld interface. Localized creep deformation and cavitation in the soft intercritical HAZ induced type IV failure whereas creep cavitation at the weld interface particles induced ferritic / austenitic interface cracking due to high creep strength mismatch across it. Micromechanisms of type IV failure and interface cracking in the ferritic / austenitic joints and different susceptibility to failure for different grades of ferritic steels are discussed based on microstructural investigation, mechanical testing and finite element analysis. (Note from indexer: paper contains many typographical errors.)

  15. Spinodal Decomposition in Functionally Graded Super Duplex Stainless Steel and Weld Metal

    Science.gov (United States)

    Hosseini, Vahid A.; Thuvander, Mattias; Wessman, Sten; Karlsson, Leif

    2018-04-01

    Low-temperature phase separations (T duplex stainless steel (SDSS) base and weld metals were investigated for short heat treatment times (0.5 to 600 minutes). A novel heat treatment technique, where a stationary arc produces a steady state temperature gradient for selected times, was employed to fabricate functionally graded materials. Three different initial material conditions including 2507 SDSS, remelted 2507 SDSS, and 2509 SDSS weld metal were investigated. Selective etching of ferrite significantly decreased in regions heat treated at 435 °C to 480 °C already after 3 minutes due to rapid phase separations. Atom probe tomography results revealed spinodal decomposition of ferrite and precipitation of Cu particles. Microhardness mapping showed that as-welded microstructure and/or higher Ni content accelerated decomposition. The arc heat treatment technique combined with microhardness mapping and electrolytical etching was found to be a successful approach to evaluate kinetics of low-temperature phase separations in SDSS, particularly at its earlier stages. A time-temperature transformation diagram was proposed showing the kinetics of 475 °C-embrittlement in 2507 SDSS.

  16. Manufacturing of welded polyblock turbine rotors for pressurized water reactor nuclear plants; Optimization of the steel grade; Effect of impurities

    International Nuclear Information System (INIS)

    Pisseloup, J.; Poitrault, I.S.; De Badereau, A.; Bocquet, P.G.

    1986-01-01

    Le Creusot Heavy Forge has been manufacturing low-pressure (LP) disks and shaft ends for 1300-MW nuclear power plants. These forgings, in weldable 1.8Cr-1Ni-0.8Mo steel, are welded by Alsthom Atlantique. With the aim of improved quality, homogeneity of mechanical properties, hardenability, and weldability, this metallurgical research has been carried out: 1. Optimization of the steel grade (the effect of silicon, manganese, and molybdenum). 2. The influence of tempering and stress relief treatment parameters. 3. The effect of impurities. These studies have led the Steel Melting Shop of Creusot-Loire Factory to invest in a high-performance process of steelmaking: the heating ladle refining process. This new process has had spectacular results that have been confirmed by investigations on cut-up industrial forgings

  17. Studies on Corrosion of Annealed and Aged 18 Ni 250 Grade Maraging Steel in Sulphuric Acid Medium

    OpenAIRE

    Poornima, T.; Jagannatha, Nayak; Shetty, A. Nityananda

    2010-01-01

    The corrosion behavior of aged and annealed sample of 18 Ni 250 grade maraging steel was investigated in varied conditions of concentration and temperature of sulphuric acid medium, using electrochemical techniques like Tafel polarization and electrochemical impedance spectroscopy (EIS). The results obtained from both the techniques are in good agreement. These results have shown increase in corrosion rate of aged specimen with increase in concentration and temperature of sulphuric acid. With...

  18. Acoustic emission during tensile deformation and fracture of nuclear grade AISI type 304 stainless steel specimens with notches

    International Nuclear Information System (INIS)

    Mukhopadhyay, C.K.; Jayakumar, T.; Baldev Raj

    1996-01-01

    Acoustic emission generated during tensile deformation and fracture of nuclear grade AISI type 304 stainless steel specimens with notches has been studied. The extent of acoustic activity generated depends on notch tip severity, notch tip blunting and tearing of the notches. The equation N=AK m applied to the acoustic emission data of the notched specimens has shown good correlation. Acoustic emission technique can be used to estimate the size of an unknown notch. (author)

  19. Fabrication of Hadfield-Cored Multi-layer Steel Sheet by Roll-Bonding with 1.8-GPa-Strength-Grade Hot-Press-Forming Steel

    Science.gov (United States)

    Chin, Kwang-Geun; Kang, Chung-Yun; Park, Jaeyeong; Lee, Sunghak

    2018-05-01

    An austenitic Hadfield steel was roll-bonded with a 1.8-GPa-strength-grade martensitic hot-press-forming (HPF) steel to fabricate a multi-layer steel (MLS) sheet. Near the Hadfield/HPF interface, the carburized and decarburized layers were formed by the carbon diffusion from the Hadfield (1.2%C) to HPF (0.35%C) layers, and could be regarded as kinds of very thin multi-layers of 35 μm in thickness. The tensile test and fractographic data indicated that the MLS sheet was fractured abruptly within the elastic range by the intergranular fracture occurred in the carburized layer. This was because C was mainly segregated at prior austenite grain boundaries in the carburized layer, which weakened grain boundaries to induce the intergranular fracture. In order to solve the intergranular facture problem, the MLS sheet was tempered at 200 °C. The stress-strain curve of the tempered MLS sheet lay between those of the HPF and Hadfield sheets, and a rule of mixtures was roughly satisfied. Tensile properties of the MLS sheet were dramatically improved after the tempering, and the intergranular fracture was erased completely. In particular, the yield strength up to 1073 MPa along with the high strain hardening and excellent ductility of 32.4% were outstanding because the yield strength over 1 GPa was hardly achieved in conventional austenitic steels.

  20. Microstructural Characterization of the Heat-Affected Zones in Grade 92 Steel Welds: Double-Pass and Multipass Welds

    Science.gov (United States)

    Xu, X.; West, G. D.; Siefert, J. A.; Parker, J. D.; Thomson, R. C.

    2018-04-01

    The microstructure in the heat-affected zone (HAZ) of multipass welds typical of those used in power plants and made from 9 wt pct chromium martensitic Grade 92 steel is complex. Therefore, there is a need for systematic microstructural investigations to define the different regions of the microstructure across the HAZ of Grade 92 steel welds manufactured using the traditional arc welding processes in order to understand possible failure mechanisms after long-term service. In this study, the microstructure in the HAZ of an as-fabricated two-pass bead-on-plate weld on a parent metal of Grade 92 steel has been systematically investigated and compared to a complex, multipass thick section weldment using an extensive range of electron and ion-microscopy-based techniques. A dilatometer has been used to apply controlled thermal cycles to simulate the microstructures in distinctly different regions in a multipass HAZ using sequential thermal cycles. A wide range of microstructural properties in the simulated materials were characterized and compared with the experimental observations from the weld HAZ. It has been found that the microstructure in the HAZ can be categorized by a combination of sequential thermal cycles experienced by the different zones within the complex weld metal, using the terminology developed for these regions based on a simpler, single-pass bead-on-plate weld, categorized as complete transformation, partial transformation, and overtempered.

  1. Study of an API migration for two XML APIs

    NARCIS (Netherlands)

    T.T. Bartholomei; K. Czarnecki; R. Lämmel (Ralf); T. van der Storm (Tijs); M.G.J. van den Brand (Mark); D. Gasevic; J. Gray

    2010-01-01

    htmlabstractAPI migration refers to adapting an application such that its dependence on a given API (the source API) is eliminated in favor of depending on an alternative API (the target API) with the source and target APIs serving the same domain. One may attempt to automate API migration by code

  2. Fatigue Crack Growth Behavior of Gas Metal Arc Welded AISI 409 Grade Ferritic Stainless Steel Joints

    Science.gov (United States)

    Lakshminarayanan, A. K.; Shanmugam, K.; Balasubramanian, V.

    2009-10-01

    The effect of filler metals such as austenitic stainless steel, ferritic stainless steel, and duplex stainless steel on fatigue crack growth behavior of the gas metal arc welded ferritic stainless steel joints was investigated. Rolled plates of 4 mm thickness were used as the base material for preparing single ‘V’ butt welded joints. Center cracked tensile specimens were prepared to evaluate fatigue crack growth behavior. Servo hydraulic controlled fatigue testing machine with a capacity of 100 kN was used to evaluate the fatigue crack growth behavior of the welded joints. From this investigation, it was found that the joints fabricated by duplex stainless steel filler metal showed superior fatigue crack growth resistance compared to the joints fabricated by austenitic and ferritic stainless steel filler metals. Higher yield strength and relatively higher toughness may be the reasons for superior fatigue performance of the joints fabricated by duplex stainless steel filler metal.

  3. Numerical and experimental study of creep of grade 91 steel at high temperature

    International Nuclear Information System (INIS)

    Lim, R.

    2011-01-01

    Grade 91 steel is a suitable candidate for structural components of the secondary and the vapour of the generation IV nuclear reactors. Their in-service lifetime will be extended to 60 years. It is necessary to consider the mechanisms involved-term during long creep to propose more reliable predictions of creep lifetimes. Necking is the main failure mechanism for creep lifetimes up to 160 kh at 500 C and 94 kh at 600 C. Necking modelling including the material creep softening leads to two bound laws including experimental lifetimes of a large number of tempered martensitic steels loaded up to 200 kh at temperature 500-700 C. The observed creep intergranular cavities are shown to affect very weekly creep strain rate. The prediction of the cavity evolution will allow estimating creep lifetimes out of experimental data domain. Their nucleation and growth, supposed to be associated to vacancy diffusion, are modelled using two classical models. The first one considers instantaneous nucleation (Raj and Ashby) and the second one continuous nucleation obeying the Dyson law (Riedel). The second one leads to two bound laws, more stable with respect to the parameter values. It allows predicting final sizes of cavities in reasonable agreement with the measured ones. Nevertheless, nucleation rate should be estimated from measured cavity densities. Nucleation of cavities by diffusion is simulated using the Raj model. This model does not allow predicted final cavity densities in agreement with the measured ones, even by considering cavity nucleation at precipitates/Laves interfaces experimentally observed and the maximum local stress concentration of a factor 2 computed using finite element calculation in a 2D plane strain hypothesis based on either simulated or real microstructures containing triple points or precipitates/Laves phases. The use of the Dyson law allows us to propose predictions of long-term creep lifetimes. Lifetime predicted using the diffusion-induced growth

  4. Effect of the welding process on the microstructure and microhardness of API 5L X80 steel welded joint used for oil transportation pipeline; Efeito do processo de soldagem sobre a microestrutura e a microdureza de juntas soldadas de aco API 5L X80 usado em tubulacoes para transporte de petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Alves, R.T.P.; Albuquerque, S.F. [Universidade Federal de Campina Grande (UFCG), PB (Brazil); Maciel, T.M.; Almeida, D.M.; Santos, M.A.

    2008-07-01

    This study had as objective to evaluate the microstructure and microhardness of API 5L X80 steel welded joints, used for pipelines to transport oil and gas, using the Shield Metal Arc Welding process with pre- heating temperature of 200 deg C and 400 deg C and the AWS E8010G electrode as filler metal. For this, besides the microhardness of the welded joint, the weld metals percentiles of micro-constituents and of columnar and regenerated grains and the medium size and extension of the heat affected zone were evaluated. The percentage of acicular ferrite in weld metal ranged from 13% to 33% which generated values of microhardness from 114 HV to 309 HV. (author)

  5. Comparison of creep rupture behavior of tungsten inert gas and electron beam welded grade 91 steel

    International Nuclear Information System (INIS)

    Dey, H.C.; Vanaja, J.; Laha, K.; Bhaduri, A.K.; Albert, S.K.; Roy, G.G.

    2016-01-01

    Creep rupture behavior of Grade 91 steel weld joints fabricated by multi-pass tungsten inert gas (TIG) and electron beam welding (EBW) processes has been studied and compared with base metal. Cross-weld creep specimens were fabricated from the X-ray radiography qualified and post weld heat treated (760°C/4 h) weld joints. Creep testing of weld joints and base metal was carried out at 650°C over a stress range of 40°120 MPa. Creep life of EBW joint is comparable to base metal; whereas multi-pass TIG joint have shown significant drop in creep life tested for the same stress level. Both types of weld joints show Type IV cracking for all the stress levels. The steady state creep rate of multi-pass TIG is found to be fifteen times than that of EBW joint for stress level of 80 MPa, which may be attributed to over tempering, more re-austenization, and fine grain structure of inter-critical and fine grain heat affected zone regions of the TIG joint. In contrast, single-pass and rapid weld thermal cycles associated with EBW process causes minimum phase transformation in the corresponding regions of heat affected zone. Microstructure studies on creep tested specimens shows creep cavities formed at the primary austenite grain boundaries nucleated on coarse carbide precipitates. The hardness measured across the weld on creep tested specimens shows significant drop in hardness in the inter-critical and fine grain heat affected zone regions of multi-pass TIG (176 VHN) in comparison to 192 VHN in the corresponding locations in EBW joint. (author)

  6. FY17 Status Report on the Initial Development of a Constitutive Model for Grade 91 Steel

    Energy Technology Data Exchange (ETDEWEB)

    Messner, M. C. [Argonne National Lab. (ANL), Argonne, IL (United States); Phan, V. -T. [Argonne National Lab. (ANL), Argonne, IL (United States); Sham, T. -L. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-07-01

    Grade 91 is a candidate structural material for high temperature advanced reactor applications. Existing ASME Section III, Subsection HB, Subpart B simplified design rules based on elastic analysis are setup as conservative screening tools with the intent to supplement these screening rules with full inelastic analysis when required. The Code provides general guidelines for suitable inelastic models but does not provide constitutive model implementations. This report describes the development of an inelastic constitutive model for Gr. 91 steel aimed at fulfilling the ASME Code requirements and being included into a new Section III Code appendix, HBB-Z. A large database of over 300 experiments on Gr. 91 was collected and converted to a standard XML form. Five families of Gr. 91 material models were identified in the literature. Of these five, two are potentially suitable for use in the ASME code. These two models were implemented and evaluated against the experimental database. Both models have deficiencies so the report develops a framework for developing and calibrating an improved model. This required creating a new modeling method for representing changes in material rate sensitivity across the full ASME allowable temperature range for Gr. 91 structural components: room temperature to 650° C. On top of this framework for rate sensitivity the report describes calibrating a model for work hardening and softening in the material using genetic algorithm optimization. Future work will focus on improving this trial model by including tension/compression asymmetry observed in experiments and necessary to capture material ratcheting under zero mean stress and by improving the optimization and analysis framework.

  7. Estimation of the aging grade of T91 steel by laser-induced breakdown spectroscopy coupled with support vector machines

    Science.gov (United States)

    Lu, Shengzi; Dong, Meirong; Huang, Jianwei; Li, Wenbing; Lu, Jidong; Li, Jun

    2018-02-01

    T91 steel is a representative martensitic heat-resistant steel widely used in high temperature compression components of industrial equipment. During the service period, the operation safety and the service life of the equipment will be affected by the change of structure and mechanical properties of the steel components, which is called material aging. In order to develop a rapid in-situ aging estimation technology of high temperature compression components surface, laser-induced breakdown spectroscopy (LIBS) coupled with support vector machine (SVM) was employed in this paper. The spectral characteristics of 10 T91 steel specimens with different aging grades were analyzed. Line intensities and the line intensity ratios (ionic/atomic and alloying element/matrix element) that indicate the change of metallographic structure were used to establish SVM models, and the results using different variable sets were compared. The model was optimized by comparing different pulse number for practical effectiveness, and the robustness of the model was investigated in dealing with the inhomogeneity of steel composition. The study results show that the estimation model obtained the best performance using line intensities and line intensity ratios averaged from 31st-60th laser pulses as input variables. The estimation accuracy of validation set was greatly improved from 75.8% to 95.3%. In addition, the model showed the outstanding capacity for handling the fluctuations of spectral signals between measuring-points (spots), which indicated that the aging estimation based on a few measuring-points is feasible. The studies presented here demonstrate that the LIBS coupled with SVM is a new useful technique for the aging estimation of steel, and would be well-suited for fast safety assessment in industrial field.

  8. In-service behaviour of creep strength enhanced ferritic steels Grade 91 and Grade 92 – Part 2 weld issues

    International Nuclear Information System (INIS)

    Parker, Jonathan

    2014-01-01

    In Creep Strength Enhanced Ferritic steels control of both composition and heat treatment of the parent steel is necessary to avoid producing components which have properties below the minimum expected by applicable codes. The degree of tempering involved in manufacture will modify the material hardness. While under most conditions hardness is reduced by tempering, exceeding the AC 1 temperature can lead to an increase in hardness. In this heat treatment the properties will be relatively poor even though the measured hardness may be apparently acceptable. Thus, care should be exercised in imposing an acceptance test of components based on simple hardness alone. Differences in parent material heat treatment and composition apparently have remarkably little influence on the creep life of the heat affect zone (HAZ). Thus, Type IV cracking in the fine grained or intercritically heat treated regions of the HAZ does not appear to directly depend on the strength of the base steel. This form of in-service damage is relatively difficult to detect using traditional methods of non-destructive testing. Moreover, since repeated heat treatment leads to over tempering and a degradation of properties, specific procedures for making and then lifing repair welds are required. The present paper summarizes examples of damage and discusses best option repairs. -- Highlights: ► For many components damage in the weld heat affected zone will be the primary source of in-service problems. ► Repair approaches should consider the influence of heat flow on metallurgical transformations. ► Both development of residual stresses and the local properties of the constituent zones influence Type IV damage. ► Serviceability of components in the creep range must consider stress, temperature and applicable material properties

  9. Experimental investigation and optimization of welding process parameters for various steel grades using NN tool and Taguchi method

    Science.gov (United States)

    Soni, Sourabh Kumar; Thomas, Benedict

    2018-04-01

    The term "weldability" has been used to describe a wide variety of characteristics when a material is subjected to welding. In our analysis we perform experimental investigation to estimate the tensile strength of welded joint strength and then optimization of welding process parameters by using taguchi method and Artificial Neural Network (ANN) tool in MINITAB and MATLAB software respectively. The study reveals the influence on weldability of steel by varying composition of steel by mechanical characterization. At first we prepare the samples of different grades of steel (EN8, EN 19, EN 24). The samples were welded together by metal inert gas welding process and then tensile testing on Universal testing machine (UTM) was conducted for the same to evaluate the tensile strength of the welded steel specimens. Further comparative study was performed to find the effects of welding parameter on quality of weld strength by employing Taguchi method and Neural Network tool. Finally we concluded that taguchi method and Neural Network Tool is much efficient technique for optimization.

  10. Time dependent design curves for a high nitrogen grade of 316LN stainless steel for fast reactor applications

    Energy Technology Data Exchange (ETDEWEB)

    Ganesh Kumar, J.; Ganesan, V.; Laha, K.; Mathew, M.D., E-mail: mathew@igcar.gov.in

    2013-12-15

    Highlights: • 316LN SS is an important high temperature structural material for sodium cooled fast reactors. • Creep strength of 316LN SS has been increased substantially by increasing the nitrogen content. • Creep design curves based on RCC-MR code procedures have been generated for this new material. • 100,000 h allowable stress at 600 °C increased by more than 40% as a result of doubling the nitrogen content in the steel. - Abstract: Type 316L(N) stainless steel (SS) containing 0.06–0.08 wt.% nitrogen is the major material for reactor assembly components of sodium cooled fast reactors (SFRs). With a view to increase the design life of SFRs to 60 years from the current life of 40 years, studies are being carried out to improve the high temperature creep and low cycle fatigue properties of 316LN SS by increasing the nitrogen content above 0.08 wt.%. In this investigation, the creep properties of a high nitrogen grade of 316LN SS containing 0.14 wt.% nitrogen have been studied. Creep tests were carried out at 550 °C, 600 °C and 650 °C at various stress levels in the range of 140–350 MPa. Creep strength was found to be significantly improved by doubling the nitrogen content in this steel. The maximum rupture life in these tests was 33,000 h. The creep data has been analyzed according to RCC-MR nuclear code procedures in order to generate the creep design curves for the high nitrogen grade of 316LN SS. Allowable stress for 100,000 h at 600 °C increased by more than 38% as a result of doubling the nitrogen content in the steel.

  11. GRINDABILITY OF SELECTED GRADES OF LOW-ALLOY HIGH-SPEED STEEL

    Directory of Open Access Journals (Sweden)

    Jan Jaworski

    2016-09-01

    Full Text Available In this paper, we presents the results of investigations studied the cutting ability and grindability of selected high-speed steels. We analysed the effect of the austenitization temperature on the grain size, the amount of retained austenite and percentage of retained austenite in HS3-1-1 steel. Furthermore, the investigations concerned on the efficiency of the keyway broaches during the whole period of operation were carried out. It was found that the value of average roughness parameter increases together with increases in the grinding depth. The investigations also show the influence of tempering conditions on the volume of carbide phases in HS3-1-1 steel.

  12. Healthcare Finder API

    Data.gov (United States)

    U.S. Department of Health & Human Services — All of the data used on the Finder.HealthCare.gov web application is available through this API. There are multiple collections of data available through the API. 1....

  13. Numerical microstructural analysis of automotive-grade steels when joined with an array of welding processes

    International Nuclear Information System (INIS)

    Gould, J.E.; Khurana, S.P.; Li, T.

    2004-01-01

    Weld strength, formability, and impact resistance for joints on automotive steels is dependent on the underlying microstructure. A martensitic weld area is often a precursor to reduced mechanical performance. In this paper, efforts are made to predict underlying joint microstructures for a range of processing approaches, steel types, and gauges. This was done first by calculating cooling rates for some typical automotive processes [resistance spot welding (RSW), resistance mash seam welding (RMSEW), laser beam welding (LBW), and gas metal arc welding (GMAW)]. Then, critical cooling rates for martensite formation were calculated for a range of automotive steels using an available thermodynamically based phase transformation model. These were then used to define combinations of process type, steel type, and gauge where welds could be formed avoiding martensite in the weld area microstructure

  14. Steel

    International Nuclear Information System (INIS)

    Zorev, N.N.; Astafiev, A.A.; Loboda, A.S.; Savukov, V.P.; Runov, A.E.; Belov, V.A.; Sobolev, J.V.; Sobolev, V.V.; Pavlov, N.M.; Paton, B.E.

    1977-01-01

    Steels also containing Al, N and arsenic, are suitable for the construction of large components for high-power nuclear reactors due to their good mechanical properties such as good through-hardening, sufficiently low brittleness conversion temperature and slight displacement of the latter with neutron irradiation. Defined steels and their properties are described. (IHOE) [de

  15. In-situ ultrasonic characterisation of M250 grade maraging steel

    International Nuclear Information System (INIS)

    Sakthipandi, K.; Rajesh Kanna, R.; Lenin, N.; Ahilandeswari, E.

    2016-01-01

    The excellent mechanical properties such as ultrahigh strength combined with good fracture toughness, hardness, ductility and corrosion resistance of maraging steels makes these steels the most preferred materials for nuclear power plants. The high strength and high fracture toughness of these maraging steels are characterised by intermetallic precipitation in iron-nickel martensite. The temperature dependent in-situ microstructural characterisation of maraging steel over wide range of temperatures is used to explore the microstructural changes in maraging steels during aging. An indigenous experimental set-up was used for in-situ measurements of ultrasonic longitudinal velocity (UL) over a wide range of temperatures from 300 to 1200 K at a heating rate of 1 K min -1 . The measured UL as a function of temperature is represented. Zone A (300-735 K) shows a gradual decrease with an increase in temperature and Zone B (735-785 K) are attributed to recovery of martensite i.e., reduction in point defects induced by quenching process. Zone C (785-835 K) is attributed to nucleation and formation of Ni 3 (Ti,Mo) coherent intermetallic precipitates. Coarsening and subsequent dissolution process of Ni 3 (Ti,Mo) intermetallic precipitates with increase in temperature is observed from 835 to 905 K (Zone D). The coarsening and partial dissolution of globular precipitation of Fe 2 Mo occurs during aging of maraging steel in the temperature region connecting to Zone E (905-1005 K). At 1005 K, the maraging steel gets transformed to austenite from martensite state, and hence, the velocity takes rapid decrease instead of taking a gradual decrease as marked by double dotted line. (author)

  16. Comparison of corrosion performance of grade 316 and grade 347H stainless steels in molten nitrate salt

    Science.gov (United States)

    Trent, M. C.; Goods, S. H.; Bradshaw, R. W.

    2016-05-01

    Stainless steel samples machined from SA-312 TP316 and SA-213 TP347H pipe were exposed to a molten nitrate salt environment at 600°C (1112°F) for up to 3000 hours in order to generate corrosion rates for use in concentrated solar power (CSP) facilities. Descaled weight loss measurements were made at 1000, 2000, and 3000 hours, with optical and scanning electron microscopy being performed on samples at the longest exposure time. The 316 and 347H alloys exhibited metal losses of 4.4 and 4.8 um respectively at 3000 hours. A linear fit to the data sets yielded annualized metal loss rates of 8.4 and 8.8 um/yr. The oxides were relatively uniform in thickness and multilayered. The inner layer consisted of a (Fe, Cr)-spinel with appreciable amounts of Mn while the outer layer was an oxide composed of only Fe. No pitting, intergranular attack, or other localized attack was found, despite the presence of a sensitized microstructure in both alloys and chloride impurity in the salt mixture. The observations presented here indicate that the two alloys perform quite comparably with respect to molten salt-induced corrosion and in that regard; either would be expected to perform satisfactorily in the intended application.

  17. Reaction behavior between B{sub 4}C, 304 grade of stainless steel and Zircaloy at 1473 K

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Ryosuke [Institute of Multidisciplinary Research Advanced Material, Tohoku University, 1-1 Katahira 2, Aoba-ku, Sendai (Japan); Ueda, Shigeru, E-mail: tie@tagen.tohokku.ac.jp [Institute of Multidisciplinary Research Advanced Material, Tohoku University, 1-1 Katahira 2, Aoba-ku, Sendai (Japan); Kim, Sun-Joong [Dept. of Materials Science and Engineering, Chosun University, 309, Pilmun-daero, Dong-gu, Gwangju (Korea, Republic of); Gao, Xu; Kitamura, Shin-ya [Institute of Multidisciplinary Research Advanced Material, Tohoku University, 1-1 Katahira 2, Aoba-ku, Sendai (Japan)

    2016-08-15

    For a better understanding of the decommissioning of the Fukushima-daiichi nuclear power plant, the melting behavior of the control blade and the channel box should be clarified. In Fukushima nuclear reactor, the channel box was made of Zircaloy-4, and the control rode is made of B{sub 4}C together with stainless steel cladding and sheath. In the study, the interaction among B{sub 4}C, stainless steel (SUS), and Zircaloy-4 was investigated at 1473 K in either argon or air atmosphere. In argon, Zircaloy is melted by the diffusion of elements from SUS, and SUS was melted at 1473 K by the diffusion of C and B. In air, SUS reacted with B{sub 2}O{sub 3} and formed an oxides melt firstly. Then, the oxidized Zircaloy contacted with this melt and fused. Moreover, the progress of core melting process during severe accident under different atmospheres was firstly discussed. - Highlights: • The interaction among the system of B{sub 4}C, grade 304 stainless steel and Zircaloy-4 were studied at 1473 K in Ar and air. • In argon, Zircaloy is melted by the diffusion of elements from SUS, and SUS was melted by the diffusion of C and B. • In air, SUS reacted with B{sub 2}O{sub 3} and formed an oxides melt. Then, the oxidized Zircaloy contacted with this melt and fused.

  18. Contribution of deformation mechanisms to strength and ductility in two Cr-Mn grade austenitic stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, A.S., E-mail: atef_saleh@s-petrol.suez.edu.eg [Materials Engineering Laboratory, Box 4200, University of Oulu, 90014 Oulu (Finland); Metallurgical and Materials Engineering Department, Faculty of Petroleum and Mining Engineering, Suez Canal University, Box 43721, Suez (Egypt); Karjalainen, L.P. [Materials Engineering Laboratory, Box 4200, University of Oulu, 90014 Oulu (Finland); Misra, R.D.K. [Center for Structural and Functional Materials and Chemical Engineering Department, University of Louisiana at Lafayette, P.O. Box 44130, Lafayette, LA 70504-4130, USA. (United States); Talonen, J. [Outokumpu Oyj, Box 140, FI-02201 Espoo (Finland)

    2013-01-01

    The role of different deformation mechanisms in controlling mechanical properties were studied in two low-Ni, Cr-Mn austenitic stainless steel grades (Types 201 and 201L) by tensile testing and microstructure examinations. Tensile tests were carried out at two different strain rates, 5 Multiplication-Sign 10{sup -4} and 10{sup -2} s{sup -1}, in the temperature range from -80 Degree-Sign C to 200 Degree-Sign C. It was observed that the flow properties and work hardening rate are affected significantly by temperature and strain rate for the concerned steels through variation of deformation mechanism. Deformation-induced austenite-to-martensite transformation (TRIP effect) is the dominant mechanism at temperatures below room temperature. From 50 Degree-Sign C up to 200 Degree-Sign C, plastic deformation is controlled by mechanical twinning (TWIP effect) and dislocation glide. The electron backscattered diffraction (EBSD) technique and transmission electron microscopy (TEM) were employed to study the plastic deformation accommodation and identify the primary deformation mechanisms operating in the deformed steels.

  19. Android quick APIs reference

    CERN Document Server

    Cinar, Onur

    2015-01-01

    The Android Quick APIs Reference is a condensed code and APIs reference for the new Google Android 5.0 SDK. It presents the essential Android APIs in a well-organized format that can be used as a handy reference. You won't find any technical jargon, bloated samples, drawn out history lessons, or witty stories in this book. What you will find is a software development kit and APIs reference that is concise, to the point and highly accessible. The book is packed with useful information and is a must-have for any mobile or Android app developer or programmer. In the Android Quick APIs Refe

  20. Comparison of Crack Growth Test Results at Elevated Temperature and Design Code Material Properties for Grade 91 Steel

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyeong-Yeon; Kim, Woo-Gon; Kim, Nak-Hyun [Korea Atomic Energy Reserach Institute, Daejeon (Korea, Republic of)

    2015-01-15

    The material properties of crack growth models at an elevated temperature were derived from the results of numerous crack growth tests for Mod.9Cr-1Mo (ASME Grade 91) steel specimens under fatigue loading and creep loading at an elevated temperature. These crack growth models were needed for defect assessment under creep-fatigue loading. The mathematical crack growth rate models for fatigue crack growth (FCG) and creep crack growth (CCG) were determined based on the test results, and the models were compared with those of the French design code RCCMRx to investigate the conservatism of the code. The French design code RCC-MRx provides an FCG model and a CCG model for Grade 91 steel in Section III Tome 6. It was shown that the FCG model of RCC-MRx is conservative, while the CCG model is non-conservative compared with the present test data. Thus, it was shown that further validation of the property was required. Mechanical strength tests and creep tests were also conducted, and the test results were compared with those of RCC-MRx.

  1. Irradiated dynamic fracture toughness of ASTM A533, Grade B, Class 1 steel plate and submerged arc weldment. Heavy section steel technology program technical report No. 41

    International Nuclear Information System (INIS)

    Davidson, J.A.; Ceschini, L.J.; Shogan, R.P.; Rao, G.V.

    1976-10-01

    As a result of the Heavy Section Steel Technology Program (HSST), sponsored by the Nuclear Regulatory Commission, Westinghouse Electric Corporation conducted dynamic fracture toughness tests on irradiated HSST Plate 02 and submerged arc weldment material. Testing performed at the Westinghouse Research and Development Laboratory in Pittsburgh, Pennsylvania, included 0.394T compact tension, 1.9T compact tension, and 4T compact tension specimens. This data showed that, in the transition region, dynamic test procedures resulted in lower (compared to static) fracture toughness results, and that weak direction (WR) oriented specimen data were lower than the strong direction (RW) oriented specimen results. Irradiated lower-bound fracture toughness results of the HSST Program material were well above the adjusted ASME Section III K/sub IR/ curve. An irradiated and nonirradiated 4T-CT specimen was tested during a fracture toughness test as a preliminary study to determine the effect of irradiation on the acoustic emission-stress intensity factor relation in pressure vessel grade steel. The results indicated higher levels of acoustic emission activity from the irradiated sample as compared to the unirradiated one at a given stress intensity factor (K) level

  2. Effect of Normalizing and Solution Heat Treatments in the Microstructure of a Dissimilar Joint Welded Between an API 5L X-52 Steel Pipe and Inconel 625

    OpenAIRE

    Soares, Jefferson Pinto; Terrones, Luis Augusto Hernandez; Paranhos, Ronaldo

    2017-01-01

    Resumo O propósito deste trabalho é comparar as mudanças na microestrutura e na dureza de um tubo de aço API 5L X-52, revestido internamente por soldagem com Inconel 625, após a execução dos tratamentos térmicos de normalização a 1100 °C por 60 min. e resfriamento ao ar, e de solubilização a 1030 °C com aquecimento por indução eletromagnética por 30 s. e resfriamento em água. Foram utilizadas técnicas de microscopia ótica (MO) e eletrônica de varredura (MEV), análise por espectroscopia de ene...

  3. Examining the microtexture evolution in a hole-edge punched into 780 MPa grade hot-rolled steel

    Energy Technology Data Exchange (ETDEWEB)

    Shin, J.H.; Kim, M.S. [Department of Printed Electronics Engineering, Sunchon National University, 315 Maegok, Sunchon, Jeonnam 540-950 (Korea, Republic of); Kim, S.I.; Seo, S.J. [POSCO Technical Research Laboratories, Gwangyang 545-090 (Korea, Republic of); Choi, S.-H., E-mail: shihoon@sunchon.ac.kr [Department of Printed Electronics Engineering, Sunchon National University, 315 Maegok, Sunchon, Jeonnam 540-950 (Korea, Republic of)

    2016-08-15

    The deformation behavior in the hole-edge of 780 MPa grade hot-rolled steel during the punching process was investigated via microstructure characterization and computational simulation. Microstructure characterization was conducted to observe the edges of punched holes through the thickness direction, and electron back-scattered diffraction (EBSD) was used to analyze the heterogeneity of the deformation. Finite element analysis (FEA) that could account for a ductile fracture criterion was conducted to simulate the deformation and fracture behaviors of 780 MPa grade hot-rolled steel during the punching process. Calculation of rotation rate fields at the edges of the punched holes during the punching process revealed that metastable orientations in Euler space were confined to specific orientation groups. Rotation-rate fields effectively explained the stability of the initial texture components in the hole-edge region during the punching process. A visco-plastic self-consistent (VPSC) polycrystal model was used to calculate the microtexture evolution in the hole-edge region during the punching process. FEA revealed that the heterogeneous effective strain was closely related to the heterogeneity of the Kernel average misorientation (KAM) distribution in the hole-edge region. A simulation of the deformation microtexture evolution in the hole-edge region using a VPSC model was in good agreement with the experimental results. - Highlights: •We analyzed the microstructure in a hole-edge punched in HR 780HB steel. •Rotation rate fields revealed the stability of the initial texture components. •Heterogeneous effective stain was closely related to the KAM distribution. •VPSC model successfully simulated the deformation microtexture evolution.

  4. Effects of DC bias on magnetic performance of high grades grain-oriented silicon steels

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Guang; Cheng, Ling [Global Energy Interconnection Research Institute, State Key Laboratory of Advanced Transmission Technology,Beijing 102211 (China); Lu, Licheng [State Grid Corporation of China, Beijing 100031 (China); Yang, Fuyao; Chen, Xin [Global Energy Interconnection Research Institute, State Key Laboratory of Advanced Transmission Technology,Beijing 102211 (China); Zhu, Chengzhi [State Grid Zhejiang Electric Power Company, Hangzhou 310007 (China)

    2017-03-15

    When high voltage direct current (HVDC) transmission adopting mono-polar ground return operation mode or unbalanced bipolar operation mode, the invasion of DC current into neutral point of alternating current (AC) transformer will cause core saturation, temperature increasing, and vibration acceleration. Based on the MPG-200D soft magnetic measurement system, the influence of DC bias on magnetic performance of 0.23 mm and 0.27 mm series (P{sub 1.7}=0.70–1.05 W/kg, B{sub 8}>1.89 T) grain-oriented (GO) silicon steels under condition of AC / DC hybrid excitation were systematically realized in this paper. For the high magnetic induction GO steels (core losses are the same), greater thickness can lead to stronger ability of resisting DC bias, and the reasons for it were analyzed. Finally, the magnetostriction and A-weighted magnetostriction velocity level of GO steel under DC biased magnetization were researched. - Highlights: • Magnetic properties of 0.23 mm and 0.27 mm series (P{sub 1.7}=0.70–1.05 W/kg, B{sub 8}>1.89 T) grain-oriented (GO) silicon steels under condition of AC / DC hybrid excitation were systematically analyzed. • Influence of DC biased magnetization on core loss, magnetostriction, and A-weighted magnetostriction velocity level of GO steel were researched. • Greater thickness and relatively lower magnetic induction (B{sub 8}>1.89 T yet) of GO steel can lead to stronger ability of resisting DC bias, and the reasons for it were analyzed.

  5. Ultrasonic Characterization of Aging Behavior in M250 Grade Maraging Steel

    Science.gov (United States)

    Yeheskel, Ori

    2009-03-01

    The increase in sound velocities during the aging of M250 maraging steel reported by Rajkumar et al. was analyzed. The present article provides a new perspective on why and to what extent the sound velocities change during aging. The main parameter that affects the elastic moduli and the sound velocities in the early and intermediate stages of aging in maraging steel is the depletion of Ni from the martensitic matrix due to Ni3Ti and Ni3Mo formation. The issue of sound velocity increase with aging time was addressed here in a few different ways to support the validity of Ni depletion.

  6. A possible recycling method for high grade steels EAFD in polymer composites.

    Science.gov (United States)

    Niubó, M; Fernández, A I; Chimenos, J M; Haurie, L

    2009-11-15

    This work evaluates the feasibility of incorporating electric arc furnace dust (EAFD), as filler in a polymer matrix, to obtain a moldable heavyweight sheet, useful for acoustic insulation in automotive industry. For this purpose EAFD from a steel factory that manufactures high quality steels, was characterized and different formulations of composites were prepared. Physical and mechanical properties, as well as fire behaviour were tested and compared with a polymer composite compounded with common mineral fillers. Optimum formulation with 25% EAFD fulfils the RoHs Directive used by automotive industry to regulate heavy metals content. Leaching test was also performed on prepared composites to classify the material after use.

  7. Application Feasibility of PRE 50 grade Super Austenitic Stainless Steel as a Steam Generator Tubing

    Energy Technology Data Exchange (ETDEWEB)

    Park, Yong Soo [Yonsei University, Seoul (Korea, Republic of); Kim, Young sik [Andong National University, Andong (Korea, Republic of); Kim, Taek Jun; Kim, Sun Tae; Park, Hui Sang [Yonsei University, Seoul (Korea, Republic of)

    1997-07-01

    The aim of this study is to evaluate the properties of the super austenitic stainless steel, SR-50A for application as steam generator tubing material. The microstructure, mechanical properties, corrosion properties, were analyzed and the results were compared between super austenitic stainless steel and Alloy 600 and Alloy 690. Super austenitic stainless steel, SR-50A is superior to Alloy 600, Alloy 690 and Alloy 800 in the mechanical properties(tensile strength, yield strength, and elongation). It was investigated that thermal conductivity of SR-50A was higher than Alloy 600. As a result of thermal treatment on super stainless steel, SR-50A, caustic SCC resistance was increased and its resistance was as much as Alloy 600TT and Alloy 690TT. In this study, optimum thermal treatment condition to improve the caustic corrosion properties was considered as 650 deg C or 550 deg C 15 hours. However, it is necessary to verify the corrosion mechanism and to prove the above results in the various corrosive environments. 27 refs., 6 tabs., 59 figs. (author)

  8. The effect of low temperatures on the fatigue of high-strength structural grade steels

    NARCIS (Netherlands)

    Walters, C.L.

    2014-01-01

    It is well-known that for fracture, ferritic steels undergo a sudden transition from ductile behavior at higher temperatures to brittle cleavage failure at lower temperatures. However, this phenomenon has not received much attention in the literature on fatigue. The so-called Fatigue Ductile-Brittle

  9. Statistical model for predicting correct amount of deoxidizer of Al-killed grade casted at slab continuous caster of Pakistan steel

    International Nuclear Information System (INIS)

    Siddiqui, A.R.; Khan, M.M.A.; Ismail, B.M.

    1999-01-01

    Oxygen is blown in Converter process to oxidize hot metal. This introduces dissolved oxygen in the metal, which may cause embrittlement, voids, inclusion and other undesirable properties in steel. The steel bath at the time of tapping contains 400 to 800 ppm oxygen. Deoxidation is carried out during tapping by adding into the tap ladle appropriate amounts of ferromanganese, ferrosilicon and/or aluminum or other special deoxidizers. In the research aluminum killed grade steel which are casted at the slab caster of Pakistan Steel were investigated. Amount of aluminum added is very critical because if we add lesser amount of aluminum then the required quantity then there will be an incomplete killing of oxygen which results uncleanness in steel. Addition of larger amount of aluminum not only increases the cost of the production but also results as higher amount of alumina, which results in nozzle clogging and increase, loses. The purpose of the research is to develop a statistical model which would predict correct amount of aluminum addition for complete deoxidation of aluminum killed grade casted at slab continuous caster of Pakistan Steel. In the model aluminum added is taken as dependent variable while tapping temperature, turn down carbon composition, turndown manganese composition and oxygen content in steel would be the independent variable. This work is based on operational practice on 130 tons Basic Oxygen furnace. (author)

  10. Functionally graded material of 304L stainless steel and inconel 625 fabricated by directed energy deposition: Characterization and thermodynamic modeling

    International Nuclear Information System (INIS)

    Carroll, Beth E.; Otis, Richard A.; Borgonia, John Paul; Suh, Jong-ook; Dillon, R. Peter; Shapiro, Andrew A.; Hofmann, Douglas C.; Liu, Zi-Kui; Beese, Allison M.

    2016-01-01

    Many engineering applications, particularly in extreme environments, require components with properties that vary with location in the part. Functionally graded materials (FGMs), which possess gradients in properties such as hardness or density, are a potential solution to address these requirements. The laser-based additive manufacturing process of directed energy deposition (DED) can be used to fabricate metallic parts with a gradient in composition by adjusting the volume fraction of metallic powders delivered to the melt pool as a function of position. As this is a fusion process, secondary phases may develop in the gradient zone during solidification that can result in undesirable properties in the part. This work describes experimental and thermodynamic studies of a component built from 304L stainless steel incrementally graded to Inconel 625. The microstructure, chemistry, phase composition, and microhardness as a function of position were characterized by microscopy, energy dispersive spectroscopy, X-ray diffraction, and microindentation. Particles of secondary phases were found in small amounts within cracks in the gradient zone. These were ascertained to consist of transition metal carbides by experimental results and thermodynamic calculations. The study provides a combined experimental and thermodynamic computational modeling approach toward the fabrication and evaluation of a functionally graded material made by DED additive manufacturing.

  11. A microstructural comparison of two nuclear-grade martensitic steels using small-angle neutron scattering

    Science.gov (United States)

    Coppola, R.; Fiori, F.; Little, E. A.; Magnani, M.

    1997-06-01

    Results are presented of a small-angle neutron scattering (SANS) study on two 10-13% Cr martensitic stainless steels of interest for nuclear applications, viz. DIN 1.4914 (MANET specification, for fusion reactors) and AISI 410. The investigation has focussed principally on microstructural effects associated with the differences in chromium content between the two alloys. The size distribution functions determined from nuclear and magnetic SANS components for the two steels given identical heat treatments are in accord with an interpretation based on the presence of ˜ 1 nm size CCr aggregates in the microstructure. Much larger (˜ 10 nm) scattering inhomogeneities with different magnetic contrast are also present and tentatively identified as carbides.

  12. Fabrication of functionally graded materials between P21 tool steel and Cu by using laser aided layered manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Jong Seol; Shin, Ki Hoon [Seoul Nat' l Univ., Seoul (Korea, Republic of)

    2013-01-15

    With the development of layered manufacturing, thermally conductive molds or molds embedding conformal cooling channels can be directly fabricated. Although P21 tool steel is widely used as a mold material because of its dimensional stability, it is not efficient for cooling molds owing to its low thermal conductivity. Hence, the use of functionally graded materials (FGMs) between P21 and Cu may circumvent a tradeoff between the strength and the heat transfer rate. As a preliminary study for the layered manufacturing of thermally conductive molds having FGM structures, one dimensional P21 Cu FGMs were fabricated by using laser aided direct metal tooling (DMT), and then, material properties such as the thermal conductivity and specific heat that are related to the heat transfer were measured and analyzed.

  13. Simulation and analysis of the residual stresses in functionally graded Al2O3 coatings on CLAM steel

    International Nuclear Information System (INIS)

    Yan Zilin; Huang Qunying; Song Yong; Guo Zhihui; Wu Yican

    2008-01-01

    Alumina coatings on CLAM steel substrate are proposed to serve as tritium, corrosion and electric insulation barriers in the design of Dual Functional Lithium Lead Test Blanket Module (DFLL-TBM) in China in the frame of ITER. In order to avoid the crack failure due to thermal expansion mismatch of the coating and the substrate, the functionally graded materials (FGM) concept was adopted. In this paper, the residual thermal stresses in the coatings were calculated with the commercial software ANSYS. It is recommended that the compositional factor, numbers of the gradient interlayers and the thickness of the FGM zone are p=0.8, N=8, H=0.6 mm, respectively, according to the simulation results. These results could be helpful and theoretical guidance to the preparation and optimization of the coatings in the future. (authors)

  14. Macrostructural and microstructural features of 1 000 MPa grade TRIP steel joint by CO2 laser welding

    Institute of Scientific and Technical Information of China (English)

    Wang Wenquan; Sun Daqian; Kang Chungyun

    2008-01-01

    Bead-on-plate CO2 laser welding of 1 000 MPa grade transformation induced plasticity (TRIP) steel was conducted under different welding powers, welding speeds and shield gases. The macrostructural and microstructural features of the welded joint were investigated. The increase of welding speed reduced the width of the weld bead and the porosities in the weld bead resulting from the different flow mode of melted metal in weld pool. The decrease of welding power or use of shield gas of helium also contributed to the reduction of porosity in the weld bead due to the alleviation of induced plasma formation, thus stabilizing the keyhole. The porosity formation intimately correlated with the evaporation of alloy element Mn in the base metal. The laser welded metal had same martensite microstructure as that of water-quenched base metal. The welding parameters which increased cooling rate all led to fine microstructures of the weld bead.

  15. Cyclic softening based on dislocation annihilation at sub-cell boundary for SA333 Grade-6 C-Mn steel

    Science.gov (United States)

    Bhattacharjee, S.; Dhar, S.; Acharyya, S. K.; Gupta, S. K.

    2018-01-01

    In this work, the response of SA333 Grade-6 C-Mn steel subjected to uniaxial and in-phase biaxial tension-torsion cyclic loading is experimented and an attempt is made to model the material behaviour. Experimentally observed cyclic softening is modelled based on ‘dislocation annihilation at low angle grain boundary’, while Ohno-Wang kinematic hardening rule is used to simulate the stress-strain hysteresis loops. The relevant material parameters are extracted from the appropriate experimental results and metallurgical investigations. The material model is plugged as user material subroutine into ABAQUS FE platform to simulate pre-saturation low cycle fatigue loops with cyclic softening and other cyclic plastic behaviour under prescribed loading. The stress-strain hysteresis loops and peak stress with cycles were compared with the experimental results and good agreements between experimental and simulated results validated the material model.

  16. Influence of aging condition and reversion austenite on fatigue property of the 300 grade 18Ni maraging steel

    International Nuclear Information System (INIS)

    Moriyama, Michihiko; Takaki, Setsuo; Kawagoishi, Norio

    2000-01-01

    The influence of aging condition on fatigue strength of the 300 grade 18Ni maraging steel has been investigated in relation to the behavior of age hardening and the formation of reversion austenite. In this study, rotating bending fatigue tests were performed for three series of specimens with different aging condition; as solution-treated without aging, aged for various time at 753 K which is the temperature applied for the industrial aging treatment, and over-aged to form a small amount of reversion austenite. Effect of reversion austenite on fatigue strength was examined using specimens with the same static strength which had been controlled by varying aging temperature and time, namely under-aging or over-aging. The main results obtained are as follows. (1) In the case of 753 K aging, the fatigue limits of specimens aged for 11 ks to 48 ks were nearly the same value, although an under-aged (2.8 ks) specimen has as much lower value as a solution-treated specimen without aging treatment. (2) A small amount of reversion austenite is effective for increasing fatigue resistance. For instance, 2 vol% of austenite was enough for improving fatigue limit of the maraging steel used, from 580 MPa to 640 MPa at the same hardness level of Hv 610. (author)

  17. Thermodynamic analysis of the conditions of deoxidation and secondary treatment of low-silicon steel grade

    Directory of Open Access Journals (Sweden)

    Євген Анатолійович Чичкарьов

    2015-10-01

    Full Text Available This article is concerned with analysis and production testing of technological solutions aimed at reducing the consumption of aluminium for steel deoxidation and reducing level of metal contamination by oxide non-metal inclusions, as well as preventing silicon reduction during out-of-furnace treatment. The conditions of low-silicon steel deoxidation and out-of-furnace treatment have been analysed. It has been found that the scope of oxygen activity variation in the converter before tapping increases while the mass fraction of carbon in the metal decreases. For the converter meltings with a mass fraction of carbon over the range 0,05-0,07 % [C] before tapping the real range of variation was 150-300 ppm. The effect of meltings carburizing on aluminium consumption and the degree of aluminium assimilation have been analysed. It has been shown that in fact the same specific consumption of ferromanganese and comparable changes within the metal oxidation change range before tapping (400-1100 ppm the addition of the carburizer decreases the consumption of aluminium by 0,15 kg/t (in amounts of pure aluminium. The variation interval of assimilation degree of aluminium, consumed for binding the dissolved oxygen in metal and for dissolution in metal has been found. It has been shown that in the melting of low-silicon steel with out- of-furnace treatment but without the use of furnace-ladle unit the rational limit of variation of mass fraction of magnesium oxide variation in the ladle slag is equal to- 6-8 % by weight

  18. Expanded austenite in nitrided layers deposited on austenitic and super austenitic stainless steel grades

    International Nuclear Information System (INIS)

    Casteletti, L.C.; Fernandes, F.A.P.; Heck, S.C.; Gallego, J.

    2010-01-01

    In this work nitrided layers deposited on austenitic and super austenitic stainless steels were analyzed through optical microscopy and X-rays diffraction analysis (XRD). It was observed that the formation of N supersaturated phase, called expanded austenite, has promoted significant increment of hardness (> 1000HV). XRD results have indicated the anomalous displacement of the diffracted peaks, in comparison with the normal austenite. This behavior, combined with peaks broadening, it was analyzed in different nitriding temperatures which results showed good agreement with the literature. (author)

  19. Corrosion and hydrogen permeation of A216 Grade WCA steel in hydrothermal magnesium-containing brines

    International Nuclear Information System (INIS)

    Haberman, J.H.; Frydrych, D.J.; Westerman, R.E.

    1988-03-01

    Corrosion rates determined at 1 month in 150/degree/C brine increased with magnesium concentration. The structure of the corrosion product, as determined by x-ray diffraction, depended upon the magnesium concentration. In brines with less than 10,000 ppM magnesium, the primary corrosion product had a spinel structure characteristic of magnetite or magnesioferrite. In brines containing magnesium concentrations greater than 20,000 ppM, the primary corrosion product had the amakinite structure characteristic of a complex iron-magnesium hydroxide. The high corrosion rates observed in brines containing high magnesium concentrations suggest that the corrosion products having the amakinite structure is less protective than corrosion products having the spinel structure. Corrosion rates in high-magnesium (inclusion) brine determined over a 6-month test duration were essentially constant. Hydrogen permeation rates observed in exposing mild steel to high-Mg/sup 2/plus// brine at 150/degree/C could be potentially damaging to a mild steel waste package container. The rate of hydrogen permeation was proportional to the brine flow rate in the autoclave. Thiourea additions to the brine increased the hydrogen permeation rate; sulfate and bromide ion additions did not. The maximum gaseous hydrogen pressure attainable is not known (based on 3Fe /plus/ 4H 2 O /plus/ Fe(sub 3)O /plus/ 4H 2 , would be /approximately/900 atmospheres), and the dependence of permeation rate on temperature is not known. 8 refs., 13 figs., 3 tabs

  20. Novel chitosan/diclofenac coatings on medical grade stainless steel for hip replacement applications

    Science.gov (United States)

    Finšgar, Matjaž; Uzunalić, Amra Perva; Stergar, Janja; Gradišnik, Lidija; Maver, Uroš

    2016-05-01

    Corrosion resistance, biocompatibility, improved osteointegration, as well the prevention of inflammation and pain are the most desired characteristics of hip replacement implants. In this study we introduce a novel multi-layered coating on AISI 316LVM stainless steel that shows promise with regard to all mentioned characteristics. The coating is prepared from alternating layers of the biocompatible polysaccharide chitosan and the non-steroid anti-inflammatory drug (NSAID), diclofenac. Electrochemical methods were employed to characterize the corrosion behavior of coated and uncoated samples in physiological solution. It is shown that these coatings improve corrosion resistance. It was also found that these coatings release the incorporated drug in controlled, multi-mechanism manner. Adding additional layers on top of the as-prepared samples, has potential for further tailoring of the release profile and increasing the drug dose. Biocompatibility was proven on human-derived osteoblasts in several experiments. Only viable cells were found on the sample surface after incubation of the samples with the same cell line. This novel coating could prove important for prolongation of the application potential of steel-based hip replacements, which are these days often replaced by more expensive ceramic or other metal alloys.

  1. FY17 Status Report on the Initial EPP Finite Element Analysis of Grade 91 Steel

    Energy Technology Data Exchange (ETDEWEB)

    Messner, M. C. [Argonne National Lab. (ANL), Argonne, IL (United States); Sham, T. -L. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-07-01

    This report describes a modification to the elastic-perfectly plastic (EPP) strain limits design method to account for cyclic softening in Gr. 91 steel. The report demonstrates that the unmodified EPP strain limits method described in current ASME code case is not conservative for materials with substantial cyclic softening behavior like Gr. 91 steel. However, the EPP strain limits method can be modified to be conservative for softening materials by using softened isochronous stress-strain curves in place of the standard curves developed from unsoftened creep experiments. The report provides softened curves derived from inelastic material simulations and factors describing the transformation of unsoftened curves to a softened state. Furthermore, the report outlines a method for deriving these factors directly from creep/fatigue tests. If the material softening saturates the proposed EPP strain limits method can be further simplified, providing a methodology based on temperature-dependent softening factors that could be implemented in an ASME code case allowing the use of the EPP strain limits method with Gr. 91. Finally, the report demonstrates the conservatism of the modified method when applied to inelastic simulation results and two bar experiments.

  2. Microstructure and properties of 700 MPa grade HSLA steel during high temperature deformation

    International Nuclear Information System (INIS)

    Chen, Xizhang; Huang, Yuming; Lei, Yucheng

    2015-01-01

    Highlights: • Hot deformation behavior of 700 MPa HSLA steel above 1200 °C in was detailed studied. • Uniform and granular bainite is formed when the deformation amount is 40%. • Deformation resistance value under steady-equilibrium state is about 56 MPa. - Abstract: A high temperature deformation experiment was conducted on a high strength low alloy (HSLA) steel Q690 using Thermecmastor-Z thermal/physical simulator. During the experiment, the specimens were heated from room temperature to 1200 °C with the heating rate of 10 °C/s and 50 °C/s, respectively. The deformation temperature was 1200 °C and the deformation amounts were 0%, 10% and 40%, respectively. The microstructures, stress–strain diagram and hardness were obtained. The results revealed that the microstructure transformation of deformed austenite was quite different from that of the normal situation. With the increasing of deformation amount, more lath-shaped microstructure and less granulous microstructure were observed. The compressive deformation effectively prevented the precipitation of carbides. Larger deformation amount or lower heating rate was conducive to the atomic diffusion, which led to the microstructure uniformity and hardness decreasing. The maximum stress was 68.4 MPa and the steady stress was about 56 MPa

  3. Influence and role of ethanol minor constituents of fuel grade ethanol on corrosion behavior of carbon steel

    International Nuclear Information System (INIS)

    Samusawa, Itaru; Shiotani, Kazuhiko

    2015-01-01

    Highlights: • The pitting factors of the minor contents of ethanol are acetic acid, Cl and H 2 O. • Formic acid in ethanol promotes general corrosion. • The H 2 O content in fuel-grade-ethanol (FGE) affects the corrosion morphology. • Acetic acid generates iron acetate, which has high solubility in FGE environments. • A pitting mechanism based on the rupture of passive film is proposed. - Abstract: The influences of organic acids, chloride and water on the corrosion behavior of carbon steel in fuel grade ethanol (FGE) environments were investigated by immersion testing in simulated FGE. The roles of acetic acid, chloride and water in pitting corrosion were studied by using X-ray photoelectron spectroscopy (XPS), auger electron spectroscopy (AES) and electrochemical experiments. The results indicated that iron acetate is generated on oxide film. Iron(II) acetate shows high solubility in FGE environments. The sites where iron(II) acetate is existed become preferential anodic sites, and chloride promotes anodic dissolution at such sites

  4. Study of the corrosion fatigue resistance of steel grades for automotive suspension springs

    Energy Technology Data Exchange (ETDEWEB)

    Mougin, J. [Ascometal CREAS, BP70045, F-57301 Hagondange Cedex (France); Mostacchi, A. [Ascometal Developpement, BP17, F-38570 Le Cheylas (France); Hersart, Y. [Allevard Rejna Autosuspensions CRDT, 201 Rue de Sin-le-Noble, BP629, F-59506 Douai Cedex (France)

    2004-07-01

    In order to reduce the total weight of vehicles for ecological and economical reasons, the car makers use down-sizing for several components of the cars. Concerning helical suspension springs, the size of the bar diameter and the number of spring coils are decreased, leading to an increase of the stress level applied on the spring. In this respect, steels with high mechanical properties are required, to achieve a good fatigue resistance of the springs. The corrosion resistance is also important for this application. Indeed, during service, the protective coating applied on the springs can be scratched by gravels, and bare underlying metal can be put in contact with the atmosphere, including humidity, drops of rain but also de-icing salts. Generally speaking, an increase of mechanical properties decreases the corrosion fatigue resistance of the steels. In this respect, a compromise needs to be found, that is why the study of corrosion fatigue resistance is very important. In order to study the corrosion fatigue resistance of spring steels, an original device and test procedure have been set up. Torsional fatigue on specimens is used to simulate the stress applied on each spring coil. The stress levels are chosen to be representative of the actual inservice loads. The specimens are shot-peened and coated in a same way as the actual springs. Scratching of the painting is performed, giving rise to small areas of bare metal. Three types of tests are performed: fatigue in air (taken as the reference level), fatigue on specimens which have been corroded previously (test similar to the spring-makers practice) and coupled corrosion fatigue. The mechanisms involved in corrosion fatigue have been studied. For all the specimens, crack initiated on corrosion pits. For the specimens corroded prior fatigue testing, the corrosion pits can be quite severe. In this case, these pits act as a surface defect which increases locally the stress concentration and accelerates the crack

  5. Diffusion bonding of IN 718 to VM 350 grade maraging steel

    Science.gov (United States)

    Crosby, S. R.; Biederman, R. R.; Reynolds, C. C.

    1972-01-01

    Diffusion bonding studies have been conducted on IN 718, VM 350 and the dissimilar alloy couple, IN 718 to maraging steel. The experimental processing parameters critical to obtaining consistently good diffusion bonds between IN 718 and VM 350 were determined. Interrelationships between temperature, pressure and surface preparation were explored for short bending intervals under vacuum conditions. Successful joining was achieved for a range of bonding cycle temperatures, pressures and surface preparations. The strength of the weaker parent material was used as a criterion for a successful tensile test of the heat treated bond. Studies of VM-350/VM-350 couples in the as-bonded condition showed a greater yielding and failure outside the bond region.

  6. Enhanced corrosion resistance of strontium hydroxyapatite coating on electron beam treated surgical grade stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Gopi, D., E-mail: dhanaraj_gopi@yahoo.com [Department of Chemistry, Periyar University, Salem 636 011, Tamilnadu (India); Centre for Nanoscience and Nanotechnology, Periyar University, Salem 636 011, Tamilnadu (India); Rajeswari, D. [Department of Chemistry, Periyar University, Salem 636 011, Tamilnadu (India); Department of Physics, Periyar University, Salem 636 011, Tamilnadu (India); Ramya, S. [Department of Chemistry, Periyar University, Salem 636 011, Tamilnadu (India); Sekar, M. [Department of Chemistry, Periyar University, Salem 636 011, Tamilnadu (India); Department of Physics, Periyar University, Salem 636 011, Tamilnadu (India); R, Pramod; Dwivedi, Jishnu [Industrial and Medical Accelerator Section, Raja Ramanna Centre for Advanced Technology, Indore 452 013, Madhya Pradesh (India); Kavitha, L., E-mail: louiskavitha@yahoo.co.in [Centre for Nanoscience and Nanotechnology, Periyar University, Salem 636 011, Tamilnadu (India); Department of Physics, Periyar University, Salem 636 011, Tamilnadu (India); Ramaseshan, R. [Thin film and Coatings Section, Surface and Nanoscience Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamilnadu (India)

    2013-12-01

    The surface of 316L stainless steel (316L SS) is irradiated by high energy low current DC electron beam (HELCDEB) with energy of 500 keV and beam current of 1.5 mA followed by the electrodeposition of strontium hydroxyapatite (Sr-HAp) to enhance its corrosion resistance in physiological fluid. The coatings were characterised by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and High resolution scanning electron microscopy (HRSEM). The Sr-HAp coating on HELCDEB treated 316L SS exhibits micro-flower structure. Electrochemical results show that the Sr-HAp coating on HELCDEB treated 316L SS possesses maximum corrosion resistance in Ringer's solution.

  7. Enhanced corrosion resistance of strontium hydroxyapatite coating on electron beam treated surgical grade stainless steel

    Science.gov (United States)

    Gopi, D.; Rajeswari, D.; Ramya, S.; Sekar, M.; R, Pramod; Dwivedi, Jishnu; Kavitha, L.; Ramaseshan, R.

    2013-12-01

    The surface of 316L stainless steel (316L SS) is irradiated by high energy low current DC electron beam (HELCDEB) with energy of 500 keV and beam current of 1.5 mA followed by the electrodeposition of strontium hydroxyapatite (Sr-HAp) to enhance its corrosion resistance in physiological fluid. The coatings were characterised by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and High resolution scanning electron microscopy (HRSEM). The Sr-HAp coating on HELCDEB treated 316L SS exhibits micro-flower structure. Electrochemical results show that the Sr-HAp coating on HELCDEB treated 316L SS possesses maximum corrosion resistance in Ringer's solution.

  8. Investigations into the fatigue behaviour of nuclear grades of austenitic stainless steel

    International Nuclear Information System (INIS)

    Mann, J.

    2015-01-01

    Full text of publication follows. Fatigue is an important problem within the nuclear industry due to the complex combination of thermal and mechanical loading that components experience during the operation of a nuclear reactor. Austenitic stainless steels are widely used within nuclear reactors for a number of applications including piping systems and pressure vessels. A number of studies have shown that austenitic stainless steel components operating within a light water reactor (LWR) environment may experience a significant reduction in fatigue life under certain circumstances, however the precise mechanisms responsible for the reduction are still not fully understood. The effects of environment are included in some fatigue assessment methods, however these are generally considered to be over-conservative and predicted fatigue lifetimes are not reflected well by service experience. This project aims to enhance the understanding of fatigue in both air and LWR environments through the synergistic use of a wide range of different microscopy techniques. It is expected that a better understanding of each of the different stages of fatigue will lead to more accurate fatigue predictions that ultimately result in better and safer lifetime predictions. This paper focuses on introducing the background behind the project, highlighting the current methods for assessing fatigue lifetimes and the motivations for the current research. The results of various initial microscopic investigations are presented, with a focus on a number of novel applications using laser scanning confocal microscopy to perform large scale analyses of fatigue fracture surfaces and test specimen gauge length surfaces. The use of surface replicas in conjunction with laser scanning confocal microscopy is discussed along with its potential applications for the assessment of fatigue damage in in-service components. Initial finite element modelling of crack growth within fatigue test specimens is discussed

  9. Corrosion Study of Super Ferritic Stainless Steel UNS S44660 (26Cr-3Ni-3Mo) and Several Other Stainless Steel Grades (UNS S31603, S32101, and S32205) in Caustic Solution Containing Sodium Sulfide

    Science.gov (United States)

    Chasse, Kevin R.; Singh, Preet M.

    2013-11-01

    Electrochemical techniques, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) were used in this study to show how the corrosion mechanism of several commercial grades of stainless steel in hot caustic solution is strongly influenced by the presence of sodium sulfide. Experimental results from super ferritic stainless steel UNS S44660 (26Cr-3Ni-3Mo) were compared to austenitic stainless steel UNS S31603, lean duplex stainless steel (DSS) UNS S32101, and standard DSS UNS S32205 in caustic solution, with and without sodium sulfide, at 443 K (170 °C). Weight loss measurements indicated that corrosion rates of UNS44660 were much lower than the other grades of stainless steel in the presence of the sodium sulfide. Potentiodynamic polarization and linear polarization resistance measurements showed that the electrochemical behavior was altered by the adhesion of sulfur species, which reduced the polarization resistances and increased the anodic current densities. SEM and XPS results imply that the surface films that formed in caustic solution containing sodium sulfide were defective due to the adsorption of sulfide, which destabilized the passive film and led to the formation of insoluble metal sulfide compounds.

  10. The Dutch xAPI Experience: xAPI Recipes

    OpenAIRE

    Berg, Alan; Scheffel, Maren; Drachsler, Hendrik; Ternier, Stefaan; Specht, Marcus

    2017-01-01

    We present the collected experiences since 2012 of the Dutch Special Interest Group (SIG) for Learning Analytics in the application of the xAPI standard and best practices around the application of xAPI in various contexts. We present three projects that apply xAPI in very different ways and publish a consistent set of xAPI recipes.

  11. FY17 Status Report on the Micromechanical Finite Element Modeling of Creep Fracture of Grade 91 Steel

    Energy Technology Data Exchange (ETDEWEB)

    Messner, M. C. [Argonne National Lab. (ANL), Argonne, IL (United States); Truster, T. J. [Univ. of Tennessee, Knoxville, TN (United States); Cochran, K. B. [DR& C Inc.; Parks, D. M. [DR& C Inc.; Sham, T. -L. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-09-01

    Advanced reactors designed to operate at higher temperatures than current light water reactors require structural materials with high creep strength and creep-fatigue resistance to achieve long design lives. Grade 91 is a ferritic/martensitic steel designed for long creep life at elevated temperatures. It has been selected as a candidate material for sodium fast reactor intermediate heat exchangers and other advanced reactor structural components. This report focuses on the creep deformation and rupture life of Grade 91 steel. The time required to complete an experiment limits the availability of long-life creep data for Grade 91 and other structural materials. Design methods often extrapolate the available shorter-term experimental data to longer design lives. However, extrapolation methods tacitly assume the underlying material mechanisms causing creep for long-life/low-stress conditions are the same as the mechanisms controlling creep in the short-life/high-stress experiments. A change in mechanism for long-term creep could cause design methods based on extrapolation to be non-conservative. The goal for physically-based microstructural models is to accurately predict material response in experimentally-inaccessible regions of design space. An accurate physically-based model for creep represents all the material mechanisms that contribute to creep deformation and damage and predicts the relative influence of each mechanism, which changes with loading conditions. Ideally, the individual mechanism models adhere to the material physics and not an empirical calibration to experimental data and so the model remains predictive for a wider range of loading conditions. This report describes such a physically-based microstructural model for Grade 91 at 600° C. The model explicitly represents competing dislocation and diffusional mechanisms in both the grain bulk and grain boundaries. The model accurately recovers the available experimental creep curves at higher stresses

  12. Evaluation of mechanical vibration effect on the residual stresses levels in steel welded joints using an Interface Matlab based on Norm API 579

    Directory of Open Access Journals (Sweden)

    R Rodrigues

    2016-10-01

    Full Text Available Nowadays with the high growth of petrochemical welding technology a great development due to high manufacturing offshore structures, storage tanks of petroleum, boilers and pressure vessels for refining plants have been done. Due to various metallurgical changes and restrictions to contraction and expansion undergone by materials when subjected to welding thermal cycle, internal stresses are generated in welded joint which are nominated residual stresses. It is generally undesirable because it can lead to several problems, such as cracks, cold stress fracture, stress corrosion, among others. Although several studies involving residual stresses have been developed in recent years, few information about the variation of the residual stresses level in welded joints when subjected to stress relief treatment by mechanical vibration have been done. Likewise, there are few information related to the comparison between the degree of efficiency by using the post-weld heat treatment and those treatment. Therefore, the goal of this work was to apply the relieve residual stresses treatment by mechanical vibration in steel welded joints used in oil industry, and compare the results with those obtained by post heat treatment and evaluate the efficiency level of this technique In addition, this works also hope to contribute for a better understanding of this technique and to find which parameters have a greater influence on the results.

  13. DIRAC RESTful API

    International Nuclear Information System (INIS)

    Casajus Ramo, A; Graciani Diaz, R; Tsaregorodtsev, A

    2012-01-01

    The DIRAC framework for distributed computing has been designed as a flexible and modular solution that can be adapted to the requirements of any community. Users interact with DIRAC via command line, using the web portal or accessing resources via the DIRAC python API. The current DIRAC API requires users to use a python version valid for DIRAC. Some communities have developed their own software solutions for handling their specific workload, and would like to use DIRAC as their back-end to access distributed computing resources easily. Many of these solutions are not coded in python or depend on a specific python version. To solve this gap DIRAC provides a new language agnostic API that any software solution can use. This new API has been designed following the RESTful principles. Any language with libraries to issue standard HTTP queries may use it. GSI proxies can still be used to authenticate against the API services. However GSI proxies are not a widely adopted standard. The new DIRAC API also allows clients to use OAuth for delegating the user credentials to a third party solution. These delegated credentials allow the third party software to query to DIRAC on behalf of the users. This new API will further expand the possibilities communities have to integrate DIRAC into their distributed computing models.

  14. Crystallographic texture control helps improve pipeline steel resistance to hydrogen-induced cracking

    Energy Technology Data Exchange (ETDEWEB)

    Caleyo, F; Hallen, J M; Herrera, O; Venegas, V [ESIQIE, Instituto Politecnico Nacional, Mexico, (Mexico); Baudin, T [Universite de Paris Sud, Orsay, (France)

    2010-07-01

    The resistance to HIC of sour service pipeline steels has been improved through several strategies but none have proven to be totally efficient in the preservation of HIC in difficult operating conditions. The crystallographic texture plays a significant role in determining the behavior of HIC in pipeline steels. The present study tried to prove that crystallographic texture control, through warm rolling schedules, helps improve pipeline steel resistance to HIC. Several samples of an API 5L X52 grade pipeline steel were produced using different thermomechanical processes (austenization, controlled rolling and recrystallization). These samples were subjected to cathodic charging. Scanning electron microscopy and automated FEG/EBSD were used to perform metallographic inspections and to collect microstructure data. The results showed that the strong y fiber texture significantly reduces or even prevents the HIC damage. It is possible to improve the HIC resistance of pipeline steels using crystallography texture control and grain boundary engineering.

  15. Influence of turbulent flow on the corrosion kinetics of API X52 pipeline steel in aqueous solutions containing H{sub 2}S

    Energy Technology Data Exchange (ETDEWEB)

    Galvan-Martinez, Ricardo; Genesca-Llongueras, Juan [Departamento Ingenieria Metalurgica, Facultad Quimica, Universidad Nacional Autonoma de Mexico, UNAM, Ciudad Universitaria, 04510 Mexico D.F. (Mexico); Mendoza-Flores, Juan; Duran-Romero, Ruben [Corrosion, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, 07730 Mexico D.F. (Mexico)

    2004-07-01

    A corrosion process can be influenced by the relative movement between the corroding environment and the metal. This relative movement could increase the heat transfer and the mass transfer of reactants towards and from the surface of the corroding metal, with a consequent increase in the corrosion rate. Also, if solid particles are present, removal of protective films, erosion and wear can occur on the metallic surface. Many industrial processes involve the movement of corrosive liquids in close contact to metallic structures. Therefore, the influence of flow on the corrosion processes is an important issue to be considered in the design and operation of industrial equipment. This influence is complex and many variables are involved. Several observations of flow-accelerated corrosion problems have been documented, particularly in the oil and gas industries, where the combined effect of flow and dissolved gases, such as hydrogen sulphide (H{sub 2}S) and carbon dioxide (CO{sub 2}), is important. Turbulent flow conditions are commonly found in industrial processes. However, few corrosion studies in controlled turbulent flow conditions are available. With the increasing necessity to describe the corrosion of metals in turbulent flow conditions some laboratory hydrodynamic systems have been used with different degrees of success. The use of the rotating cylinder electrode (RCE), as a laboratory hydrodynamic test system, has gained popularity in corrosion studies. This popularity is due to its characteristics, such as, its operation mainly at turbulent flow conditions; its well understood mass transfer properties and its easiness of construction and operation. The aim of the present work is to explore the effect that turbulent flow conditions have on the electrochemical kinetics of steel samples immersed in aqueous environments containing H{sub 2}S. In order to control the turbulent flow conditions in the laboratory, a rotating cylinder electrode (RCE) was used. In

  16. GIBS API for Developers

    Data.gov (United States)

    National Aeronautics and Space Administration — API using Global Imagery Browse Services (GIBS) designed to deliver global, full-resolution satellite imagery to users in a highly responsive manner, enabling...

  17. Constant Load SCC Initiation Response of Alloy 22 (UNS N06022), Titanium Grade 7 and Stainless Steels at 1050C

    International Nuclear Information System (INIS)

    Young, L.M.; Catlin, G.M.; Andresen, P.L.; Gordon, G.M.

    2002-01-01

    This paper provides an update on research addressing the effects of material condition and applied stress on stress corrosion cracking (SCC) in waste package and drip shield materials for the Yucca Mountain Project. Time-to-failure experiments are being performed on smooth bar tensile specimens in a hot, concentrated, mixed-salt solution chosen to simulate concentrated Yucca Mountain water. The effects of applied stress, welding, surface finish, shot peening, cold work, crevicing, and aging treatment are being investigated for Alloy 22 (UNS N06022). Aging treatments were designed to produce topologically close-packed phases (TCP) and long-range ordering (LRO) and are under investigation as worse-case scenarios for possible microstructures in Alloy 22 (UNS N06022). Titanium Grade 7 and 3 16NG stainless steel are included in the matrix, as they are identified for drip shield and waste package components, respectively. Sensitized 304SS specimens are included in the test matrix to provide benchmark data. This research complements high-resolution crack-growth-rate experiments currently being performed in a parallel research project

  18. X-Ray Diffraction Profile Analysis for Characterizing Isothermal Aging Behavior of M250 Grade Maraging Steel

    Science.gov (United States)

    Mahadevan, S.; Jayakumar, T.; Rao, B. P. C.; Kumar, Anish; Rajkumar, K. V.; Raj, Baldev

    2008-08-01

    X-ray diffraction (XRD) studies were carried out to characterize aging behavior of M250 grade maraging steel samples subjected to isothermal aging at 755 K for varying durations of 0.25, 1, 3, 10, 40, 70, and 100 hours. Earlier studies had shown typical features of precipitation hardening, wherein the hardness increased to a peak value due to precipitation of intermetallics and decreased upon further aging (overaging) due to reversion of martensite to austenite. Intermetallic precipitates, while coherent, are expected to increase the microstrain in the matrix. Hence, an attempt has been made in the present study to understand the microstructural changes in these samples using XRD line profile analysis. The anisotropic broadening with diffraction angle observed in the simple Williamson Hall (WH) plot has been addressed using the modified WH (mWH) approach, which takes into account the contrast caused by dislocations on line profiles, leading to new scaling factors in the WH plot. The normalized mean square strain and crystallite size estimated from mWH have been used to infer early precipitation and to characterize aging behavior. The normalized mean square strain has been used to determine the Avrami exponent in the Johnson Mehl Avrami (JMA) equation, which deals with the kinetics of precipitation. The Avrami exponent thus determined has matched well with values found by other methods, as reported in literature.

  19. Prediction Model of Cutting Parameters for Turning High Strength Steel Grade-H: Comparative Study of Regression Model versus ANFIS

    Directory of Open Access Journals (Sweden)

    Adel T. Abbas

    2017-01-01

    Full Text Available The Grade-H high strength steel is used in the manufacturing of many civilian and military products. The procedures of manufacturing these parts have several turning operations. The key factors for the manufacturing of these parts are the accuracy, surface roughness (Ra, and material removal rate (MRR. The production line of these parts contains many CNC turning machines to get good accuracy and repeatability. The manufacturing engineer should fulfill the required surface roughness value according to the design drawing from first trail (otherwise these parts will be rejected as well as keeping his eye on maximum metal removal rate. The rejection of these parts at any processing stage will represent huge problems to any factory because the processing and raw material of these parts are very expensive. In this paper the artificial neural network was used for predicting the surface roughness for different cutting parameters in CNC turning operations. These parameters were investigated to get the minimum surface roughness. In addition, a mathematical model for surface roughness was obtained from the experimental data using a regression analysis method. The experimental data are then compared with both the regression analysis results and ANFIS (Adaptive Network-based Fuzzy Inference System estimations.

  20. Influence of Hold Time and Stress Ratio on Cyclic Creep Properties Under Controlled Tension Loading Cycles of Grade 91 Steel

    International Nuclear Information System (INIS)

    Kim, Woo Gon; Park, Jae Young; Jang, Jin Sung; Ekaputra, I Made Wicaksana; Kim, Seon Jin

    2017-01-01

    Influences of hold time and stress ratio on cyclic creep properties of Grade 91 steel were systemically investigated using a wide range of cyclic creep tests, which were performed with hold times (HTs) of 1 minute, 3 minutes, 5 minutes, 10 minutes, 20 minutes, and 30 minutes and stress ratios (R) of 0.5, 0.8, 0.85, 0.90, and 0.95 under tension loading cycles at 600°C. Under the influence of HT, the rupture time increased to HT = 5 minutes at R = 0.90 and R = 0.95, but there was no influence at R = 0.50, 0.80, and 0.85. The creep rate was constant regardless of an increase in the HT, except for the case of HT = 5 minutes at R = 0.90 and R = 0.95. Under the influence of stress ratio, the rupture time increased with an increase in the stress ratio, but the creep rate decreased. The cyclic creep led to a reduction in the rupture time and an acceleration in the creep rate compared with the case of monotonic creep. Cyclic creep was found to depend dominantly on the stress ratio rather than on the HT. Fracture surfaces displayed transgranular fractures resulting from microvoid coalescence, and the amount of microvoids increased with an increase in the stress ratio. Enhanced coarsening of the precipitates in the cyclic creep test specimens was found under all conditions

  1. Effect of 4-(N,N-diethylamino)benzaldehyde thiosemicarbazone on the corrosion of aged 18 Ni 250 grade maraging steel in phosphoric acid solution

    International Nuclear Information System (INIS)

    Poornima, T.; Nayak, Jagannath; Nityananda Shetty, A.

    2011-01-01

    Highlights: → DEABT as corrosion inhibitor for maraging steel in phosphoric acid. → Inhibition efficiency increases with increase in inhibitor concentration. → Inhibition efficiency decreases with increase in temperature. → Adsorption obeys Langmuir adsorption isotherm. - Abstract: 4-(N,N-diethylamino)benzaldehyde thiosemicarbazone (DEABT) was studied for its corrosion inhibition property on the corrosion of aged 18 Ni 250 grade maraging steel in 0.67 M phosphoric acid at 30-50 deg. C by potentiodynamic polarization, EIS and weight loss techniques. Inhibition efficiency of DEABT was found to increase with the increase in DEABT concentration and decrease with the increase in temperature. The activation energy E a and other thermodynamic parameters (ΔG ads 0 , ΔH ads 0 , ΔS ads 0 ) have been evaluated and discussed. The adsorption of DEABT on aged maraging steel surface obeys the Langmuir adsorption isotherm model and the inhibitor showed mixed type inhibition behavior.

  2. The wettability modification of bio-grade stainless steel in contact with simulated physiological liquids by the means of laser irradiation

    International Nuclear Information System (INIS)

    Hao, L.; Lawrence, J.; Li, L.

    2005-01-01

    Early surface events that occur rapidly upon implantation of a biomaterial into biological fluids determine the subsequent response. These involve wetting by physiological liquids followed by adsorption of proteins and cells to the biomaterials surface. A CO 2 laser and high power diode laser (HPDL) were used to modify the surface properties of the material and thus manipulate the wettability of the material and its interaction with physiological liquids. The contact angles, θ, of selected test liquids including simulated physiological liquids shows that the wettability of the stainless steel improved after CO 2 and HPDL treatment. The determined adhesion work of stainless steel towards stimulated physiological fluid enhanced after laser treatment, implying better interaction with the biological liquids. It is demonstrated that the laser could be a novel and controllable technique for enhancing the biocompatibility of bio-grade stainless steel

  3. Small punch tensile/fracture test data and 3D specimen surface data on Grade 91 ferritic/martensitic steel from cryogenic to room temperature.

    Science.gov (United States)

    Bruchhausen, Matthias; Lapetite, Jean-Marc; Ripplinger, Stefan; Austin, Tim

    2016-12-01

    Raw data from small punch tensile/fracture tests at two displacement rates in the temperature range from -196 °C to room temperature on Grade 91 ferritic/martensitic steel are presented. A number of specimens were analyzed after testing by means of X-ray computed tomography (CT). Based on the CT volume data detailed 3D surface maps of the specimens were established. All data are open access and available from Online Data Information Network (ODIN)https://odin.jrc.ec.europa.eu. The data presented in the current work has been analyzed in the research article "On the determination of the ductile to brittle transition temperature from small punch tests on Grade 91 ferritic-martensitic steel" (M. Bruchhausen, S. Holmström, J.-M. Lapetite, S. Ripplinger, 2015) [1].

  4. Required grades of hull steel plates in consideration of fracture toughness; Hakai jinsei wo koryoshita sentaiyo koban shiyo kubun ni kansuru ichikosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Yajima, H; Yamamoto, M; Ogaki, Y [Hiroshima University, Hiroshima (Japan). Faculty of Engineering

    1997-10-01

    This paper discusses the required grades of hull steel plates based on the steel ship rule of Nippon Kaiji Kyokai (NK). The minimum value of the allowable crack length in NK rule (critical safety crack length at 0degC just before brittle unstable crack causing fatal fracture) was estimated. In the case where the estimated crack tip exists in a matrix, the crack length was a minimum of 200-210mm, while nearly 60mm in a fusion line at high-heat-input welded joint. The allowable crack lengths estimated from a specified value in the NK rule were fairly different. The allowable crack length at 0degC was also estimated from the minimum value in V-notch Charpy impact test. The private proposal on the required grades of hull steel plates in consideration of fracture toughness was discussed. Thirty-five percent of crack lengths found in real ships is 100mm or less, however, cracks of 250-400mm long are frequently found suggesting the allowable crack length of 400mm. The required grade integrally considering required values and design conditions is demanded to secure the reliability of hull strength. 5 refs., 5 figs., 2 tabs.

  5. Comparative study in the induced corrosion by sulfate reducing microorganisms, in a stainless steel 304L sensitized and a carbon steel API X65; Estudio comparativo de la corrosion inducida por microorganismos sulfatorreductores, en un acero inoxidable 304L sensibilizado y un acero al carbono API X65

    Energy Technology Data Exchange (ETDEWEB)

    Diaz S, A.; Gonzalez F, E.; Arganis J, C.; Luna C, P.; Carapia M, L. [ININ, Carretera Mexico-Toluca Km. 36.5, 52045 Estado de Mexico (Mexico)]. e-mail: ads@nuclear.inin.mx

    2004-07-01

    In spite of the operational experience related with the presence of the phenomenon of microbiological corrosion (MIC) in industrial components, it was not but until the decade of the 80 s when the nuclear industry recognized its influence in some systems of Nuclear Generating Power plants. At the moment, diverse studies that have tried to explain the generation mechanism of this phenomenon exist; however, they are even important queries that to solve, especially those related with the particularities of the affected metallic substrates. Presently work, the electrochemical behavior of samples of stainless steel AISI 304L sensitized is evaluated and the carbon steel APIX65, before the action of sulfate reducing microorganisms low the same experimental conditions; found that for the APIX65 the presence of this type of bacteria promoted the formation of a stable biofilm that allowed the maintenance of the microorganisms that damaged the material in isolated places where stings were generated; while in the AISI 304L, it was not detected damage associated to the inoculated media. The techniques of Resistance to the Polarization and Tafel Extrapolation, allowed the calculation of the speed of uniform corrosion, parameter that doesn't seem to be influenced by the presence of the microorganisms; while that noise electrochemical it distinguished in real time, the effect of the sulfate reducing in the steel APIX65. (Author)

  6. Alloy Design of Martensitic 9Cr-Boron Steel for A-USC Boiler at 650 °C — Beyond Grades 91, 92 and 122

    Science.gov (United States)

    Abe, Fujio; Tabuchi, M.; Tsukamoto, S.

    Boundary hardening is shown to be the most important strengthening mechanism in creep of tempered martensitic 9% Cr steel base metal and welded joints at 650 °C. The enrichment of soluble boron near prior austenite grain boundaries (PAGBs) by the GB segregation is essential for the reduction of coarsening rate of M23C6 carbides near PAGBs, enhancing the boundary and sub-boundary hardening near PAGBs, and also for the change in α/γ transformation behavior in heat-affected-zone (HAZ) of welded joints during heating of welding, producing the same microstructure in HAZ as in the base metal. Excess addition of nitrogen to the 9Cr-boron steel promotes the formation of boron nitrides during normalizing heat treatment, which consumes most of soluble boron and degrades the creep strength. A NIMS 9Cr steel (MARBN; Martensitic 9Cr steel strengthened by boron and MX nitrides) with 120-150 ppm boron and 60-90 ppm nitrogen, where no boron nitride forms during normalizing heat treatment, exhibits not only much higher creep strength of base metal than Grades 91, 92 and 122 but also substantially no degradation in creep strength due to Type IV fracture in HAZ of welded joints at 650°C. The protective Cr2O3-rich scale forms on the surface of 9Cr steel by pre-oxidation treatment in Ar gas, which significantly improves the oxidation resistance in steam at 650°C.

  7. Mars Atmospheric Aggregation System API

    Data.gov (United States)

    National Aeronautics and Space Administration — The {MAAS} API is an open source REST API built to help make it easier and more efficient to build interactive applications that want to utilize the wealth of...

  8. Data.gov CKAN API

    Data.gov (United States)

    General Services Administration — The data.gov catalog is powered by CKAN, a powerful open source data platform that includes a robust API. Please be aware that data.gov and the data.gov CKAN API...

  9. Avaliação da microestrutura e propriedades mecânicas de metais de solda obtidos por processos de soldagem manual e automatizado utilizado na soldagem de aço API 5L X80 Evaluation of microstructure and mechanical properties of weld metals obtained by manual and automated welding process used in the welding of API 5L X80 steel

    Directory of Open Access Journals (Sweden)

    Siderley Fernandes Albuquerque

    2011-12-01

    Full Text Available O objetivo do trabalho foi avaliar as características da zona termicamente afetada (ZTA e a microestrutura e propriedades mecânicas de metais de solda de juntas soldadas do aço API 5L X80, obtidos para quatro diferentes procedimentos de soldagem utilizando processos manuais e automatizados. Para isto, chapas do referido aço foram soldadas por processo manual ao Arco Elétrico com Eletrodo Revestido (SMAW, utilizando 473 e 673 K como temperaturas de interpasses e o eletrodo celulósico AWS E8010-G como consumível; por processo ao Arco Elétrico com Arame Tubular (FCAW robotizado, utilizando o arame AWS E71T- 1C como metal de adição e argônio com 25%CO2 como gás de proteção; por processo a Arco Elétrico com Eletrodo de Tungstênio (GTAW mecanizado na raiz da solda, usando o arame ER70S-3 e argônio como gás de proteção. As análises microestruturais foram relacionadas com os resultados de ensaios de impacto Charpy nos metais de solda e com os perfis de microdureza Vickers ao longo da junta soldada. Os resultados indicaram maiores percentuais de Ferrita Acicular e maiores valores de resistência ao impacto nos metais de solda e uma menor extensão e granulometria da ZTA, associado ao procedimento de soldagem utilizando processo automatizado com maior velocidade de soldagem.The objective of this work was to evaluate the heat affected zone characteristics and weld metals microstructure and mechanical properties of API 5L X80 steel welded joints, obtained for four different welding procedures using manual and automated processes. For this, plates of this steel were welded by manual Shielded Metal Arc Welding (SMAW process with interpasses temperatures of 473 e 673 K, and using AWS E8010-G electrode as filler metals; robotized Flux Cored Arc Welding (FCAW process, using AWS E71T-1C wire and Ar25%CO2 as consumable and mechanized Gas Tungsten Arc Welding (GTAW process, for the root pass using AWS ER70S-3 and Ar as consumable .The

  10. Investigation of cause of cracking of high-strength 30HGSNA grade steel subjected to stresses and corrosive agents

    International Nuclear Information System (INIS)

    Sitko, E.

    1995-01-01

    It has been found out that 30HGSNA steel undergo cracking under action of stresses in aqueous solutions containing oxygen, while it show high resistance in deoxidated solutions. The purpose of such phenomena is the existence of sulfur inclusions in steel which are a centers of denting corrosion. That points acting as a stresses concentrators where pH factor decreases including hydrogen formation and its absorption in the metal. That mechanism is the main purpose of brittle steel cracking observed in oxygen rich solutions. (author)

  11. A new generation of ultra high strength steel pipelines

    International Nuclear Information System (INIS)

    Brozda, J.; Zeman, M.; Weglowski, M.

    2008-01-01

    For many years an increased demand for natural gas can be observed. Ultra high-strength pipelines with higher operating pressures and/or reduced wall thickness are a means to reduce transmission costs. Motivated by reduced investment costs (overcharge a few billion of dollars), tend towards the development of a new grade of pipeline steel with microalloying element for example Nb, that potentially lowers the total cost of long-distance gas pipelines by 5 - 15%. New long distance pipelines have budgets in excess of several billion dollars. This paper describes mechanical properties of new generation of pipelines steel with higher content of niobium and the influence the welding thermal cycles on the microstructure and brittle fracture resistance. The resistance to cold cracking has also been determined. It was found that the new steel has close properties to API X70 grade steels, but is cheaper in manufacturing and installation. The steel has been covered by the amended EN 10028-5 standard and proper modifications will also be made in other European standards. (author)

  12. Effect of Ni Addition on Bainite Transformation and Properties in a 2000 MPa Grade Ultrahigh Strength Bainitic Steel

    Science.gov (United States)

    Tian, Junyu; Xu, Guang; Jiang, Zhengyi; Hu, Haijiang; Zhou, Mingxing

    2018-05-01

    The effects of Nickle (Ni) addition on bainitic transformation and property of ultrahigh strength bainitic steels are investigated by three austempering processes. The results indicate that Ni addition hinders the isothermal bainite transformation kinetics, and decreases the volume fraction of bainite due to the decrease of chemical driving force for nucleation and growth of bainite transformation. Moreover, the product of tensile strength and total elongation (PSE) of high carbon bainitic steels decreases with Ni addition at higher austempering temperatures (220 and 250 °C), while it shows no significant difference at lower austempering temperature (200 °C). For the same steel (Ni-free or Ni-added steel), the amounts of bainite and RA firstly increase and then decrease with the increase of the austempering temperature, resulting in the highest PSE in the sample austempered at temperature of 220 °C. In addition, the effects of austempering time on bainite amount and property of high carbon bainitic steels are also analyzed. It indicates that in a given transformation time range of 30 h, more volume of bainite and better mechanical property in high carbon bainitic steels can be obtained by increasing the isothermal transformation time.

  13. The API petroassist network

    International Nuclear Information System (INIS)

    Boortz, M.J.; Jardim, G.M.; Horn, S.A.; Disbennett, D.B.

    1993-01-01

    Past spill responses, such as those in the Exxon Valdez and American Trader incidents, demonstrated the value of companies volunteering their in-house experts and local knowledge to help other companies in spill response. The American Petroleum Institute (API) formed the PetroAssist Network to provide a means for oil companies to readily gain access to the expertise and communications equipment of other oil companies when needed for spill responses. An API work group developed the PetroAssist Network legal agreement and management and activation procedures. To minimize red tape and reduce the burden on members, existing systems were used whenever possible. The network became operational on January 1, 1992, with more than 40 members

  14. Associated particle imaging (API)

    International Nuclear Information System (INIS)

    1998-05-01

    Associated Particle Imaging (API) is an active neutron probe technique that provides a 3-D image with elemental composition of the material under interrogation, and so occupies a unique niche in the interrogation of unknown objects. The highly penetrating nature of neutrons enables API to provide detailed information about targets of interest that are hidden from view. Due to the isotropic nature of the induced reactions, radiation detectors can be set on the same side of the object as the neutron source, so that the object can be interrogated from a single side. At the heat of the system is a small generator that produces a continuous, monoenergetic flux of neutrons. By measuring the trajectory of coincident alpha particles that are produced as part of the process, the trajectory of the neutron can be inferred. Interactions between a neutron and the material in its path often produce a gamma ray whose energy is characteristic of that material. When the gamma ray is detected, its energy is measured and combined with the trajectory information to produce a 3-D image of the composition of the object being interrogated. During the course of API development, a number of improvements have been made. A new, more rugged sealed Tube Neutron Generator (STNG) has been designed and fabricated that is less susceptible to radiation damage and better able to withstand the rigors of fielding than earlier designs. A specialized high-voltage power supply for the STNG has also been designed and built. A complete package of software has been written for the tasks of system calibration, diagnostics and data acquisition and analysis. A portable system has been built and field tested, proving that API can be taken out of the lab and into real-world situations, and that its performance in the field is equal to that in the lab

  15. Construction of continuous cooling transformation (CCT) diagram using Gleeble for coarse grained heat affected zone of SA106 grade B steel

    Science.gov (United States)

    Vimalan, G.; Muthupandi, V.; Ravichandran, G.

    2018-05-01

    A continuous cooling transformation diagram is constructed for simulated coarse grain heat affected zone (CGHAZ) of SA106 grade B carbon steel. Samples are heated to a peak temperature of 1200°C in the Gleeble thermo mechanical simulator and then cooled at different cooling rates varying from 0.1°C/s to 100°C/s. Microstructure of the specimens simulated at different cooling rates were characterised by optical microscopy and hardness was assessed by Vicker's hardness test and micro-hardness test. Transformation temperatures and the corresponding phase fields were identified from dilatometric curves and the same could be confirmed by correlating with the microstructures at room temperature. These data were used to construct the CCT diagram. Phase fields were found to have ferrite, pearlite, bainite and martensite or their combinations. With the help of this CCT diagram it is possible to predict the microstructure and hardness of coarse grain HAZ experiencing different cooling rates. The constructed CCT diagram becomes an important tool in evaluating the weldability of SA106 grade B carbon steel.

  16. New stainless steels of ferrite-martensite grade and perspectives of their application in thermonuclear facilities and fast reactors

    International Nuclear Information System (INIS)

    Ajtkhozhin, Eh.S.; Maksimkin, O.P.

    2007-01-01

    Review of scientific literature for last 5 years in which results on study of radiation effect on ferrite-martensite steels - construction materials of fast reactors and most probable candidates for first wall and blanket of the thermonuclear facilities ITER and Demo - are presented. Alongside with this a prior experimental data on study of microstructure changing and physical- mechanical properties of ferrite-martensite steel EhP-450 - the material of hexahedral case of spent assembly of BN-350 fast reactor- are cited. Principal attention was paid to considering of radiation effects of structural components content changing and ferrite-martensite steel swelling irradiated at comparatively low values of radiation damage climb rate

  17. Plasma nitriding of steels

    CERN Document Server

    Aghajani, Hossein

    2017-01-01

    This book focuses on the effect of plasma nitriding on the properties of steels. Parameters of different grades of steels are considered, such as structural and constructional steels, stainless steels and tools steels. The reader will find within the text an introduction to nitriding treatment, the basis of plasma and its roll in nitriding. The authors also address the advantages and disadvantages of plasma nitriding in comparison with other nitriding methods. .

  18. Web API Fragility : How Robust is Your Web API Client

    NARCIS (Netherlands)

    Espinha, T.; Zaidman, A.; Gross, H.G.

    2014-01-01

    Web APIs provide a systematic and extensible approach for application-to-application interaction. A large number of mobile applications makes use of web APIs to integrate services into apps. Each Web API’s evolution pace is determined by their respective developer and mobile application developers

  19. Learning Bing maps API

    CERN Document Server

    Sinani, Artan

    2013-01-01

    This is a practical, hands-on guide with illustrative examples, which will help you explore the vast universe of Bing maps.If you are a developer who wants to learn how to exploit the numerous features of Bing Maps then this book is ideal for you. It can also be useful for more experienced developers who wish to explore other areas of the APIs. It is assumed that you have some knowledge of JavaScript, HTML, and CSS. For some chapters a working knowledge of .Net and Visual Studio is also needed.

  20. Open Astronomy Catalogs API

    Science.gov (United States)

    Guillochon, James; Cowperthwaite, Philip S.

    2018-05-01

    We announce the public release of the application program interface (API) for the Open Astronomy Catalogs (OACs), the OACAPI. The OACs serve near-complete collections of supernova, tidal disruption, kilonova, and fast stars data (including photometry, spectra, radio, and X-ray observations) via a user-friendly web interface that displays the data interactively and offers full data downloads. The OACAPI, by contrast, enables users to specifically download particular pieces of the OAC dataset via a flexible programmatic syntax, either via URL GET requests, or via a module within the astroquery Python package.

  1. Effects of Testing Method on Stretch-Flangeability of Dual-Phase 980/1180 Steel Grades

    Science.gov (United States)

    Madrid, Mykal; Van Tyne, Chester J.; Sadagopan, Sriram; Pavlina, Erik J.; Hu, Jun; Clarke, Kester D.

    2018-06-01

    Challenging fuel economy and safety standards in the automotive industry have led to the need for materials with higher strength while maintaining levels of formability that meet component manufacturing requirements. Advanced high-strength steels, such as dual-phase steels with tensile strengths of 980 MPa and 1180 MPa, are of interest to address this need. Increasing the strength of these materials typically comes at the expense of ductility, which may result in problems when stamping parts with trimmed or sheared edges, as cracking at the sheared edge may occur at lower strains. Here, hole expansion tests were performed with different punch geometries (conical and flat-bottom) and different edge conditions (sheared and machined) to understand the effects of testing conditions on performance, and these results are discussed in terms of mechanical properties and microstructures.

  2. Correlation Between Intercritical Heat-Affected Zone and Type IV Creep Damage Zone in Grade 91 Steel

    Science.gov (United States)

    Wang, Yiyu; Kannan, Rangasayee; Li, Leijun

    2018-04-01

    A soft zone in Cr-Mo steel weldments has been reported to accompany the infamous Type IV cracking, the highly localized creep damage in the heat-affected zone of creep-resistant steels. However, the microstructural features and formation mechanism of this soft zone are not well understood. In this study, using microhardness profiling and microstructural verification, the initial soft zone in the as-welded condition was identified to be located in the intercritical heat-affected zone of P91 steel weldments. It has a mixed structure, consisting of Cr-rich re-austenitized prior austenite grains and fine Cr-depleted, tempered martensite grains retained from the base metal. The presence of these further-tempered retained grains, originating from the base metal, is directly responsible for the hardness reduction of the identified soft zone in the as-welded condition. The identified soft zone exhibits a high location consistency at three thermal stages. Local chemistry analysis and thermodynamic calculation show that the lower chromium concentrations inside these retained grains thermodynamically decrease their potentials for austenitic transformation during welding. Heterogeneous grain growth is observed in the soft zone during postweld heat treatment. The mismatch of strengths between the weak Cr-depleted grains and strong Cr-rich grains enhances the creep damage. Local deformation of the weaker Cr-depleted grains accelerates the formation of creep cavities.

  3. Effect of Welding Heat Input on the Microstructure and Toughness in Simulated CGHAZ of 800 MPa-Grade Steel for Hydropower Penstocks

    Directory of Open Access Journals (Sweden)

    Qingfeng Ding

    2017-03-01

    Full Text Available To determine the appropriate welding heat input for simulated coarse grained heat affected zone (CGHAZ of 800 MPa-grade steel used in hydropower penstocks, the microstructural evolution, hardness, and 50% fraction appearance transition temperature (50% FATT were investigated. The results indicated that when the cooling rate (heat input is reduced (increased, the impact toughness at −20 °C and hardness of the simulated CGHAZ decreased. When the heat input increased from 18 to 81 kJ/cm, the 50% FATT increased from −80 °C to −11 °C. At 18 kJ/cm, the microstructures consisted of lath bainite and granular bainite, but lath bainite decreased with increasing heat input. The increase in the 50% FATT was attributed mainly to an increase in the austenite grain size and effective grain size, and a decrease in lath bainite and the fraction of HAGBs (misorientation: ≥15°.

  4. Corrosion Effects on the Fatigue Crack Propagation of Giga-Grade Steel and its Heat Affected Zone in pH Buffer Solutions for Automotive Application

    Science.gov (United States)

    Lee, H. S.

    2018-03-01

    Corrosion fatigue crack propagation test was conducted of giga-grade steel and its heat affected zone in pH buffer solutions, and the results were compared with model predictions. Pure corrosion effect on fatigue crack propagation, particularly, in corrosive environment was evaluated by means of the modified Forman equation. As shown in results, the average corrosion rate determined from the ratio of pure corrosion induced crack length to entire crack length under a cycle load were 0.11 and 0.37 for base metal and heat affected zone, respectively, with load ratio of 0.5, frequency of 0.5 and pH 10.0 environment. These results demonstrate new interpretation methodology for corrosion fatigue crack propagation enabling the pure corrosion effects on the behavior to be determined.

  5. Microstructural and microanalysis investigations of bond titanium grade1/low alloy steel st52-3N obtained by explosive welding

    Energy Technology Data Exchange (ETDEWEB)

    Gloc, Michal, E-mail: michalgloc@wp.pl [Warsaw University of Technology, Faculty of Materials Science and Engineering (Poland); Wachowski, Marcin [Military University of Technology in Warsaw, Faculty of Mechanical Engineering (Poland); Plocinski, Tomasz; Kurzydlowski, Krzysztof Jan [Warsaw University of Technology, Faculty of Materials Science and Engineering (Poland)

    2016-06-25

    Explosive welding is a solid state welding process that is used for the metallurgical joining of two or more dissimilar metals. In this process, forces of controlled detonations are utilized to accelerate one metal plate into another. As a result, an atomic bond is created. It is considered as a cold-welding process since it allows metals to be joined without losing their pre-bonding properties. The metal plates are joined under the influence of very high pressure which causes local plastic deformation and grain refining at the bond interface. Moreover, between the parent and flyer plate some local melting zones are formed. The explosively cladded steel plates are used in the chemical, petrochemical and nuclear industry due to their good corrosion resistance and mechanical properties. In this work, microstructural and chemical analyses of clad plates obtained by the explosive method are presented. The clad plates studied were made of titanium grade 1 explosively bonded with a thin layer of st52-3N low alloy steel. The microstructure was evaluated using light (LM) and scanning electron microscopes (SEM), while chemical composition was assessed using energy dispersive spectroscopy (EDS). It was found that the bond area had different microstructure, chemical composition and microhardness than the bonded materials. In the junction between the base steel and the cladding, a strongly defected transient zone with altered chemical composition in comparison with the bonded metals was revealed. - Highlights: • Explosive welding as an effective method for joining similar or dissimilar metals. • Slip brands, elongated grains and twins correlated with high plastic deformations. • Investigations of the local melted zones, formed at the interface of the clads. • Mechanical properties connected with microstructural changes and deformation.

  6. Construction of long-term isochronous stress-strain curves by a modeling of short-term creep curves for a Grade 9Cr-1Mo steel

    International Nuclear Information System (INIS)

    Kim, Woo-Gon; Yin, Song-Nan; Koo, Gyeong-Hoi

    2009-01-01

    This study dealt with the construction of long-term isochronous stress-strain curves (ISSC) by a modeling of short-term creep curves for a Grade 9Cr-1Mo steel (G91) which is a candidate material for structural applications in the next generation nuclear reactors as well as in fusion reactors. To do this, tensile material data used in the inelastic constitutive equations was obtained by tensile tests at 550degC. Creep curves were obtained by a series of creep tests with different stress levels of 300MPa to 220MPa at an identical controlled temperature of 550degC. On the basis of these experimental data, the creep curves were characterized by Garofalo's creep model. Three parameters of P 1 , P 2 and P 3 in Garofalo's model were properly optimized by a nonlinear least square fitting (NLSF) analysis. The stress dependency of the three parameters was found to be a linear relationship. But, the P 3 parameter representing the steady state creep rate exhibited a two slope behavior with different stress exponents at a transient stress of about 250 MPa. The long-term creep curves of the G91 steel was modeled by Garofalo's model with only a few short-term creep data. Using the modeled creep curves, the long-term isochronous curves up to 10 5 hours were successfully constructed. (author)

  7. The effect of various deformation processes on the corrosion behavior of casing and tubing carbon steels in sweet environment

    Science.gov (United States)

    Elramady, Alyaa Gamal

    The aim of this research project is to correlate the plastic deformation and mechanical instability of casing steel materials with corrosion behavior and surface change, in order to identify a tolerable degree of deformation for casing steel materials. While the corrosion of pipeline and casing steels has been investigated extensively, corrosion of these steels in sweet environments with respect to plastic deformation due to bending, rolling, autofrettage, or handling needs more investigation. Downhole tubular expansion of pipes (casings) is becoming standard practice in the petroleum industry to repair damaged casings, shutdown perforations, and ultimately achieve mono-diameter wells. Tubular expansion is a cold-drawing metal forming process, which consists of running conical mandrels through casings either mechanically using a piston or hydraulically by applying a back pressure. This mechanism subjects the pipes to large radial plastic deformations of up to 30 pct. of the inner diameter. It is known that cold-working is a way of strengthening materials such as low carbon steel, but given that this material will be subjected to corrosive environments, susceptibility to stress corrosion cracking (SCC) should be investigated. This research studies the effect of cold-work, in the form of cold-rolling and cold-expansion, on the surface behavior of API 5CT steels when it is exposed to a CO2-containing environment. Cold-work has a pronounced influence on the corrosion behavior of both API 5CT K55 and P110 grade steels. The lowest strength grade steel, API 5CT K55, performed poorly in a corrosive environment in the slow strain rate test. The ductile material exhibited the highest loss in strength and highest susceptibility to stress corrosion cracking in a CO 2-containing environment. The loss in strength declined with cold-rolling, which can be ascribed to the surface compressive stresses induced by cold-work. On the other hand, API 5CT P110 grade steels showed higher

  8. Evaluation of deformation behavior of in grains and grain boundaries of L-grade austenitic stainless steel 316L

    International Nuclear Information System (INIS)

    Nagashima, Nobuo; Hayakawa, Masao; Tsukada, Takashi; Kaji, Yoshiyuki; Miwa, Yukio; Ando, Masami; Nakata, Kiyotomo

    2009-01-01

    In this study, micro-hardness tests and AFM observations were performed on SUS 316L low-carbon austenitic stainless steel pre-strained by cold rolling to investigate its deformation behavior. The following results were obtained. Despite the fact that the same plastic strain was applied, post-tensile test AFM showed narrower slip-band spacing in a reduction in area of 30% cold-rolled specimen than the unrolled specimen. Concentrated slip bands were observed near grain boundaries. These were presumably due to slip blocking at grain boundaries. SCC sensitivity increased at a hardness of 300 or higher, the frequency occurrence of a hardness of 300 or higher in the micro-hardness measurements was compared. The micro-hardness did not exceed 300 both within grains and at grain boundaries in the unrolled and up to a reduction in area of 20% cold-rolled specimens of before and after the tensile tests. Micro-hardness exceeding 300 was found to occur frequently in after tensile test specimens with a reduction in area of 30% or more, particularly at grain boundaries. It is suggested that the nonuniformity of deformation at grain boundaries plays an important role of IGSCC crack propagation mechanism of low-carbon austenitic stainless steel. (author)

  9. In situ x-ray diffraction investigations during low energy ion nitriding of austenitic stainless steel grade 1.4571

    International Nuclear Information System (INIS)

    Manova, D; Mändl, S; Gerlach, J W; Hirsch, D; Neumann, H; Rauschenbach, B

    2014-01-01

    Insertion of nitrogen into austenitic stainless steel leads to anomalously fast nitrogen diffusion and the formation of an expanded face-centred cubic phase which is known to contain a large amount of mechanical stress. In situ x-ray diffraction (XRD) measurements during low energy nitrogen ion implantation into steel 316Ti at 300–550 °C allow a direct view into diffusion and phase formation. While the layer growth is directly observable from the decreasing substrate reflection intensity, the time evolution of the intensities for the expanded phase reflection is much more complex: several mechanisms including at least formation and annealing of defects, twinning, reduction of the crystal symmetry, or grain rotation may be active inside the expanded phase, besides the thermally activated decay of the metastable expanded phase. This locally varying coherence length or scattering intensity from the expanded phase is furthermore a function of temperature and time, additionally complicating the deconvolution of XRD spectra for stress and concentration gradients. As no concise modelling of this coherence length is possible at present, a simple qualitative model assuming a dependence of the scattering intensity on the depth, influence by stress and plastic flow during the nitriding process is proposed for understanding the underlying processes. (paper)

  10. Effect of aging on impact properties of ASTM A890 Grade 1C super duplex stainless steel

    International Nuclear Information System (INIS)

    Martins, Marcelo; Forti, Leonardo Rodrigues Nogueira

    2008-01-01

    Super duplex stainless steels in the solution annealed condition are thermodynamically metastable systems which, when exposed to heat, present a strong tendency to 'seek' the most favorable thermodynamic condition. The main purpose of this study was to characterize the microstructure of a super duplex stainless steel in the as cast and solution annealed conditions, and to determine the influence of aging heat treatments on its impact strength, based on Charpy impact tests applied to V-notched test specimens. The sigma phase was found to begin precipitating at heat treatment temperatures above 760 deg. C and to dissolve completely only above 1040 deg. C, with the highest peak concentration of this phase appearing at close to 850 deg. C. Heat treatments conducted at temperatures of 580 deg. C to 740 deg. C led to a reduction of the energy absorbed in the Charpy impact test in response to the precipitation of a particulate phase with particle sizes ranging from 0.5 μm to 1.0 μm, with a chromium and iron-rich chemical composition

  11. Interpretation of toughness tests performed on A533, grade B steel in the transition regime. Modelling and numerical analysis

    International Nuclear Information System (INIS)

    Eripret, C.

    1994-01-01

    Modelling the fracture behaviour of pressure vessel steels is of major importance for related structural integrity assessments. It is essential to understand how the micromechanisms control the transition between ductile and brittle fracture for predicting geometry effects on transition temperature. To meet this goal, a model has been developed at EDF/R and DD in the framework of local approach to fracture. Its experimental validation has been achieved by analysing toughness tests performed by AEA Technology for a pressure vessel steel in the transition regime. This large data base has evidenced the specimen thickness effects on toughness properties of the material, as well as influence of prior ductile crack growth. Predictions of the model have been compared with experiments, which shows that the transition curve K 1C = f (T) can be drawn from model predictions and compared with the RCCM or ASME design curve. Substantial safety margins have been exhibited. They are greater for thin specimens (10 mm) than for thicker specimens (230 mm). However, the transition curve in the upper transition region is still underestimated by the model (for temperatures higher than RTNDT + 50 deg C). Improvement should be made to account for important plasticity development and significant crack growth. (author). 30 figs., 10 tabs., 12 refs

  12. Application of Response Surface Methodology for Modeling of Postweld Heat Treatment Process in a Pressure Vessel Steel ASTM A516 Grade 70.

    Science.gov (United States)

    Peasura, Prachya

    2015-01-01

    This research studied the application of the response surface methodology (RSM) and central composite design (CCD) experiment in mathematical model and optimizes postweld heat treatment (PWHT). The material of study is a pressure vessel steel ASTM A516 grade 70 that is used for gas metal arc welding. PWHT parameters examined in this study included PWHT temperatures and time. The resulting materials were examined using CCD experiment and the RSM to determine the resulting material tensile strength test, observed with optical microscopy and scanning electron microscopy. The experimental results show that using a full quadratic model with the proposed mathematical model is YTS = -285.521 + 15.706X1 + 2.514X2 - 0.004X1(2) - 0.001X2(2) - 0.029X1X2. Tensile strength parameters of PWHT were optimized PWHT time of 5.00 hr and PWHT temperature of 645.75°C. The results show that the PWHT time is the dominant mechanism used to modify the tensile strength compared to the PWHT temperatures. This phenomenon could be explained by the fact that pearlite can contribute to higher tensile strength. Pearlite has an intensity, which results in increased material tensile strength. The research described here can be used as material data on PWHT parameters for an ASTM A516 grade 70 weld.

  13. Intro to the Zotero API

    Directory of Open Access Journals (Sweden)

    Amanda Morton

    2013-04-01

    Full Text Available In this lesson, you’ll learn how to use python with the Zotero API to interact with your Zotero library. The Zotero API is a powerful interface that would allow you to build a complete Zotero client from scratch if you so desired. But like most APIs, it works in small, discrete steps, so we have to build our way up to the complicated requests we might want to use to access our Zotero libraries. But this incremental building gives us plenty of time to learn as we go along.

  14. Bluetooth API Implementation into Android

    Directory of Open Access Journals (Sweden)

    Konev Sergey

    2017-01-01

    Full Text Available Bluetooth is a popular method of communication between devices. Many smartphones today have the capability to communicate using Bluetooth. Android developers sometimes need to use Bluetooth in their projects. Android OS provides a powerful API for Bluetooth that allows to simplify scanning the environment for devices, pairing and connecting, data transfer between devices and more. However, utilizing the Bluetooth API can be difficult for first-time users. The objective of this article is to demonstrate the key points of implementing Bluetooth API in the Android application.

  15. Long-term strength and allowable stresses of grade 10Kh9MFB and X10CrMoVNb9-1 (T91/P91) chromium heat-resistant steels

    Science.gov (United States)

    Skorobogatykh, V. N.; Danyushevskiy, I. A.; Schenkova, I. A.; Prudnikov, D. A.

    2015-04-01

    Currently, grade X10CrMoVNb9-1 (T91, P91) and 10Kh9MFB (10Kh9MFB-Sh) chromium steels are widely applied in equipment manufacturing for thermal power plants in Russia and abroad. Compilation and comparison of tensile, impact, and long-term strength tests results accumulated for many years of investigations of foreign grade X10CrMoVNb9-1, T91, P91, and domestic grade 10Kh9MFB (10Kh9MFB-Sh) steels is carried out. The property identity of metals investigated is established. High strength and plastic properties of steels, from which pipes and other products are made, for operation under creep conditions are confirmed. Design characteristics of long-term strength on the basis of tests with more than one million of hour-samples are determined ( and at temperatures of 500-650°C). The table of recommended allowable stresses for grade 10Kh9MFB, 10Kh9MFB-SH, X10CrMoVNb9-1, T91, and P91 steels is developed. The long-time properties of pipe welded joints of grade 10Kh9MFB+10Kh9MFB, 10Kh9MFB-Sh+10Kh9MFB-Sh, X10CrMoVNb9-1+X10CrMoVNb9-1, P91+P91, T91+T91, 10Kh9MFB (10Kh9MFB-Sh)+X10CrMoVNb9-1(T/P91) steels is researched. The welded joint reduction factor is experimentally determined.

  16. A combined experimental and computational study of deformation in grains of biomedical grade 316LVM stainless steel

    International Nuclear Information System (INIS)

    You, X.; Connolley, T.; McHugh, P.E.; Cuddy, H.; Motz, C.

    2006-01-01

    In this work three-dimensional crystal plasticity finite element models are used to simulate the tensile deformation of a thin 316LVM stainless steel specimen. Such models are of interest for predicting the mechanical response of cardiovascular stents, typically made from thin struts of this material. Detailed experimental analysis of the mechanical response of the specimen during deformation is performed using scanning electron microscopy, digital photogrammetry and orientation imaging microscopy to examine microscale strain distribution, plastic slip and grain reorientation. At the macroscale, the models are found to give good predictions of the stress-strain response of the specimen, and at the microscale the models are found to give good predictions of the strain distribution and the active slip systems in the different grains. The models are less successful in predicting grain reorientations. This, however, is shown to be quite sensitive to the choice of latent hardening ratio

  17. A combined experimental and computational study of deformation in grains of biomedical grade 316LVM stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    You, X. [National Centre for Biomedical Engineering Science, National University of Ireland, Galway (Ireland); Connolley, T. [National Centre for Biomedical Engineering Science, National University of Ireland, Galway (Ireland); McHugh, P.E. [National Centre for Biomedical Engineering Science, National University of Ireland, Galway (Ireland) and Department of Mechanical and Biomedical Engineering, National University of Ireland, University Road, Galway (Ireland)]. E-mail: peter.mchugh@nuigalway.ie; Cuddy, H. [National Centre for Biomedical Engineering Science, National University of Ireland, Galway (Ireland); Motz, C. [Erich Schmid Institute, Austrian Academy of Sciences, Jahnstrasse 12, A-8700 Leoben (Austria)

    2006-10-15

    In this work three-dimensional crystal plasticity finite element models are used to simulate the tensile deformation of a thin 316LVM stainless steel specimen. Such models are of interest for predicting the mechanical response of cardiovascular stents, typically made from thin struts of this material. Detailed experimental analysis of the mechanical response of the specimen during deformation is performed using scanning electron microscopy, digital photogrammetry and orientation imaging microscopy to examine microscale strain distribution, plastic slip and grain reorientation. At the macroscale, the models are found to give good predictions of the stress-strain response of the specimen, and at the microscale the models are found to give good predictions of the strain distribution and the active slip systems in the different grains. The models are less successful in predicting grain reorientations. This, however, is shown to be quite sensitive to the choice of latent hardening ratio.

  18. Experimental and numerical analysis concerning the behaviour of OL50 steel grade specimens coated with polyurea layer under dynamics loadings

    Directory of Open Access Journals (Sweden)

    Bucur Florina

    2015-01-01

    Full Text Available This study refers to an experimental and numerical evaluation of a polyurea coating layer influence on the dynamic behaviour of OL50 specimens. Mechanical quasi-static and dynamic tensile tests were performed in axial loading conditions, for 2 mm steel plate specimens. Several metallic specimens have been previously coated with 1.5 mm and 3 mm respectively thickness polyurea layer and tested in traction. The findings results indicate that the presence of polyurea changes the loading pattern of metallic material in the necking area. In terms of polyurea coated metal specimens fracture, there was clearly observed a change of fracture limit. One possible explanation of this phenomenon is the modification of triaxiality state in the necking zone, fact proven by the numerical simulations. Test results indicate that the presence of polyurea layer delays the necking onset phenomenon which precedes the OL50 metallic specimen fracture.

  19. Macelignan inhibits bee pathogenic fungi Ascophaera apis growth through HOG1 pathway

    Directory of Open Access Journals (Sweden)

    Y.K. Shin

    2016-01-01

    Full Text Available Ascosphaera apis is a bee pathogen that causes bee larvae infection disease, to which treatment is not yet well investigated. The aim of this study was to investigate antifungal susceptibility in vitro against A. apis and to identify a new antifungal agent for this pathogen through minimal inhibitory concentration (MIC assay and western blot analysis. Macelignan had 1.56 and 3.125 μg/mL MIC against A. apis after 24 and 48 h, respectively, exhibiting the strongest growth inhibition against A. apis among the tested compounds (corosolic acid, dehydrocostus lactone, loganic acid, tracheloside, fangchinoline and emodin-8-O-β-D-glucopyranoside. Furthermore, macelignan showed a narrow-ranged spectrum against various fungal strains without any mammalian cell cytotoxicity. In spite of miconazole having powerful broad-ranged anti-fungal activity including A. apis, it demonstrated strong cytotoxicity. Therefore, even if macelignan alone was effective as an antifungal agent to treat A. apis, combined treatment with miconazole was more useful to overcome toxicity, drug resistance occurrence and cost effectiveness. Finally, HOG1 was revealed as a target molecule of macelignan in the anti-A. apis activity by inhibiting phosphorylation using S. cerevisiae as a model system. Based on our results, macelignan, a food-grade antimicrobial compound, would be an effective antifungal agent against A. apis infection in bees.

  20. Creep rupture behavior of 9Cr–1.8W–0.5Mo–VNb (ASME grade 92) ferritic steel weld joint

    Energy Technology Data Exchange (ETDEWEB)

    Sakthivel, T., E-mail: tsakthivel@igcar.gov.in; Vasudevan, M.; Laha, K., E-mail: laha@igcar.gov.in; Parameswaran, P.; Chandravathi, K.S.; Panneer Selvi, S.; Maduraimuthu, V.; Mathew, M.D.

    2014-01-03

    Creep rupture behavior of 9Cr–1.8W–0.5Mo–VNb (ASME grade 92) ferritic steel weld joint fabricated by activated TIG (A-TIG) welding process have been investigated at 923 K over a stress range of 80–150 MPa. The weld joint was comprise of fusion zone, heat affected zone (HAZ) and base metal. The HAZ consisted of coarse prior-austenite grain (CGHAZ), fine prior-austenite grain (FGHAZ) and intercritical (ICHAZ) regions in an order away from the fusion zone to base metal. A hardness trough was observed at the outer edge of HAZ of the weld joint. TEM investigation revealed the presence of coarse M{sub 23}C{sub 6} precipitates and recovery of martensite lath structure into subgrain in the ICHAZ of the weld joint, leading to the hardness trough. The weld joint exhibited lower creep rupture lives than the base metal at relatively lower stresses. Creep rupture failure location of the weld joint was found to shift with applied stress. At high stresses fracture occurred in the base metal, whereas failure location shifted to FGHAZ at lower stresses with significant decrease in rupture ductility. SEM investigation of the creep ruptured specimens revealed precipitation of Laves phase across the joint, more extensively in the FGHAZ. On creep exposure, the hardness trough was found to shift from the ICHAZ to FGHAZ. Extensive creep cavitation was observed in the FGHAZ and was accompanied with the Laves phase, leading to the premature type IV failure of the steel weld joint at the FGHAZ.

  1. Magnetic and mechanical properties of Cu (75 wt%) – 316L grade stainless steels synthesized by ball milling and annealing

    Energy Technology Data Exchange (ETDEWEB)

    Mondal, Bholanath, E-mail: bholanath_mondal@yahoo.co.in [Department of Central Scientific Services, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India); Chabri, Sumit [Department of Metallurgy and Materials Engineering, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103 (India); Sardar, Gargi [Department of Zoology, Baruipur College, South 24 Parganas, 743610 (India); Bhowmik, Nandagopal [Department of Metallurgy and Materials Engineering, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103 (India); Sinha, Arijit, E-mail: arijitsinha2@yahoo.co.in [School of Materials Science and Engineering, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103 (India); Chattopadhyay, Partha Protim [Department of Metallurgy and Materials Engineering, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103 (India)

    2015-05-01

    Elemental powders of Cu (75 wt%) and 316-stainless steel (25 wt%) has been subjected to ball milling upto 70 h followed by isothermal annealing at the temperature range of 350–750 °C for 1 h to investigate the microstructural evolution along with magnetic and mechanical properties. After 40 h of milling, the bcc Fe is almost dissolved in the solid solution of Cu but no significant change has been observed in the XRD pattern after 70 h of milling, Annealing of the alloy has resulted in precipitation of nanocrystalline bcc-Fe in Cu which triggers the soft ferromagnetic properties. The extensive mechanical characterization has been done at the microstructural scale by nanoindentation technique which demonstrates a hardening behavior of the compacted and annealed alloys due to possible precipitation of nanocrystalline bcc-Fe in Cu. - Highlights: • Nanocrystalline phases with partial amorphorization obtained after 70 h of milling. • Precipitation and grain coarsening of Fe and Cu after annealing as observed by XRD. • Annealing of the ball milled sample upto 550 {sup o}C has evolved ferromagnetic behavior. • Nanoindentation predicts a hardening behavior of annealed ball milled samples.

  2. Preparation Femtosecond Laser Prevention for the Cold-Worked Stress Corrosion Crackings on Reactor Grade Low Carbon Stainless Steel

    CERN Document Server

    John Minehara, Eisuke

    2004-01-01

    We report here that the femtosecond lasers like low average power Ti:Sapphire lasers, the JAERI high average power free-electron laser and others could peel off and remove two stress corrosion cracking (SCC) origins of the cold-worked and the cracking susceptible material, and residual tensile stress in hardened and stretched surface of low-carbon stainless steel cubic samples for nuclear reactor internals as a proof of principle experiment except for the third origin of corrosive environment. Because a 143 °C and 43% MgCl2 hot solution SCC test was performed for the samples to simulate the cold-worked SCC phenomena of the internals to show no crack at the laser-peered off strip on the cold-worked side and ten-thousands of cracks at the non-peeled off on the same side, it has been successfully demonstrated that the femtosecond lasers could clearly remove the two SCC origins and could resultantly prevent the cold-worked SCC.

  3. Ultrasound stress measurements for API X65 pipes; Avaliacao por ultra-som das tensoes impostas em tubo API X-65

    Energy Technology Data Exchange (ETDEWEB)

    Medeiros, Raimundo C.; Santos, Ramon Loback Medeiros [TRANSPETRO - PETROBRAS Transporte S.A., Rio de Janeiro, RJ (Brazil); Bittencourt, Marcelo S.Q.; Lamy, Carlos A. [Instituto de Engenharia Nuclear (IEN), Rio de Janeiro, RJ (Brazil); Donato, Guilherme V.P. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)

    2003-07-01

    Risks of damages or even premature collapse of buried pipelines caused by their interaction with geologically unstable soils are well-established phenomena. Therefore, both monitoring and measurements of the actual loads transmitted by the soil to the pipeline are mandatory requirements, and define the necessity of developing new nondestructive techniques capable to carry out through evaluations of these loads in field. The aim of this paper has been placed on the presentation of a cutting-edge ultrasonic technology applied to stress measurements. To accomplish this purpose a series of ultrasonic tests were conducted on tensile specimens extracted from API 5L Grade X-65 steel pipe to determine its acoustic birefringence. The results have evidenced the acoustic birefringence to be a technique sufficiently consistent and, consequently, it shall be considered as a promising tool for the evaluation of the structural integrity of metallic structures in the near future. In addition, it was also observed that the use of this technique allows measuring the residual stress resulting from the pipe manufacturing process. (author)

  4. Development of TS590MPa grade high tensile strength steel for automotive anti-collision parts; Shogeki kyushuyo 590MPa kyu kochoryoku koban no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Miura, K; Takagi, S; Furukimi, O; Hira, T; Obara, T [Kawasaki Steel Corp., Tokyo (Japan); Tanimura, S [University of Osaka Prefecture, Osaka (Japan)

    1997-10-01

    The effects of strain rate on the deformation behavior of steels were investigated to find the most appropriate micro-structure of steel for anti-crash parts of automobiles, such as front-side-members. The dual phase steel absorbed a higher amount of energy during dynamic deformation than other steels with the same static yield strength. The increase of volume fraction of the austenite phase in the dual phase steel deteriorates the dynamic deformation behavior. The FEM analysis for crash test of HAT-sectional sheet box also showed the superior performance of the dual phase steel. 4 refs., 7 figs., 1 tab.

  5. Effect of thermomechanical treatments on the microstructure and mechanical properties of 9%Cr martensitic steel (Grade 91)

    International Nuclear Information System (INIS)

    Piozin, Emma

    2014-01-01

    9%Cr tempered martensitic steels are currently used in fossil power and in petrochemical plants. Due to attractive properties and manufacturing costs, there are also potential candidates for structural components of new generation nuclear reactors. To optimize their high temperatures mechanical properties (∼500-650 C), a thermal-mechanical treatment based on 'ausforming' is being considered. It is composed of an austenitization step, followed by warm-rolling of metastable austenite at intermediate temperatures (500-600 C), then quenching and tempering. This study aims at understanding the effects of each of these steps, and particularly the warm-rolling of the metastable austenite, on the resulting microstructure and mechanical properties. After applying a variety of thermal-mechanical treatment conditions, with or without warm rolling, the microstructures were systematically characterized at various scales by SEM, TEM, SANS, and neutron diffraction. Martensite laths are finer and dislocations density is higher in warm-rolled samples compared to thermally treated samples. In some cases, warm-rolled + tempered microstructures were partially recrystallized, showing that tempered martensite keeps a 'memory' of previous rolling of metastable austenite. Contrary to what was expected, warm-rolling did not affect precipitation, which is principally governed by austenitizing and tempering temperatures. Warm-rolling lead to a remarkable increase in tensile and creep strength but strongly impairs ductility and significantly increases the ductile-to-brittle transition temperature. Some of the warm-rolled materials are sensitive to intergranular failure at both low (Charpy impact tests) and high temperature (creep tests). Moreover, warm-rolling of metastable austenite does not improve, and even increases cyclic softening. All microstructural features have been quantitatively linked to mechanical properties at 20 C, by applying a structural hardening model

  6. Ductile failure analysis of defective API X65 pipes based on stress-modified fracture strain criterion

    International Nuclear Information System (INIS)

    Oh, Chang Kyun; Kim, Yun Jae; Baek, Jong Hyun; Kim, Young Pyo; Kim, Woo Sik

    2006-01-01

    A local failure criterion for the API X65 steel is applied to predict ductile failure of full-scale API X65 pipes with simulated corrosion and gouge defects under internal pressure. The local failure criterion is the stress-modified fracture strain for the API X65 steel as a function of the stress triaxiality (defined by the ratio of the hydrostatic stress to the effective stress). Based on detailed FE analyses with the proposed local failure criteria, burst pressures of defective pipes are estimated and compared with experimental data. The predicted burst pressures are in good agreement with experimental data. Noting that an assessment equation against the gouge defect is not yet available, parametric study is performed, from which a simple equation is proposed to predict burst pressure for API X65 pipes with gouge defects

  7. X-ray diffraction study of microstructural changes during fatigue damage initiation in steel pipes

    Energy Technology Data Exchange (ETDEWEB)

    Pinheiro, B., E-mail: bianca@lts.coppe.ufrj.br [Laboratory of Mechanics of Lille (LML), UMR CNRS 8107, University of Lille 1, Boulevard Paul Langevin, Cite Scientifique, 59655 Villeneuve d' Ascq (France); Lesage, J. [Laboratory of Mechanics of Lille (LML), UMR CNRS 8107, University of Lille 1, Boulevard Paul Langevin, Cite Scientifique, 59655 Villeneuve d' Ascq (France); Pasqualino, I. [Subsea Technology Laboratory (LTS), Ocean Engineering Department, COPPE/Federal University of Rio de Janeiro, PO Box 68508, Cidade Universitaria, CEP 21945-970, Rio de Janeiro/RJ (Brazil); Benseddiq, N. [Laboratory of Mechanics of Lille (LML), UMR CNRS 8107, University of Lille 1, Boulevard Paul Langevin, Cite Scientifique, 59655 Villeneuve d' Ascq (France); Bemporad, E. [Interdepartmental Laboratory of Electron Microscopy (LIME), University of Rome TRE, Via Della Vasca Navale 79, 00146 Rome (Italy)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer In this work we study the fatigue damage evolution in an API 5L X60 steel. Black-Right-Pointing-Pointer Microstructural changes and residual stresses are evaluated during fatigue tests. Black-Right-Pointing-Pointer Microdeformations and macro residual stresses are estimated by X-ray diffraction. Black-Right-Pointing-Pointer Results are discussed in view of an indicator of fatigue damage initiation. Black-Right-Pointing-Pointer This indicator could allow the prediction of residual life before macrocracking. - Abstract: Steel pipes used in the oil and gas industry undergo the action of cyclic loads that can cause their failure by fatigue. A consistent evaluation of the fatigue damage during the initiation phase should fundamentally be based on a nanoscale approach, i.e., at the scale of the dislocation network, in order to take into account the micromechanisms of fatigue damage that precede macrocrack initiation and propagation until the final fracture. In this work, microstructural changes related to fatigue damage initiation are investigated in the API 5L X60 grade steel, used in pipe manufacturing. Microdeformations and macro residual stress are evaluated using X-ray diffraction in real time during alternating bending fatigue tests performed on samples cut off from an X60 steel pipe. The aim of this ongoing work is to provide ground for further development of an indicator of fatigue damage initiation in X60 steel. This damage indicator could allow a good residual life prediction of steel pipes previously submitted to fatigue loading, before macroscopic cracking, and help to increase the reliability of these structures.

  8. Coating of Bio-mimetic Minerals-Substituted Hydroxyapatite on Surgical Grade Stainless Steel 316L by Electrophoretic Deposition for Hard tissue Applications

    Science.gov (United States)

    Govindaraj, Dharman; Rajan, Mariappan

    2018-02-01

    Third-era bio-implant materials intend to empower particular live cell reactions at the atomic level, these materials represented with a resorbable and biocompatibility that bodies recuperate once they have been embedded. Necessitate to decrease expenses in public health services has required the utilization of surgical grade stainless steel (SS 316L) as the most inexpensive choice for orthodontic and orthopaedic implants. 316L SS is one of the broadly used implant biomaterials in orthodontic and orthopaedic surgeries. Yet, frequently those discharge for toxic metal ions is confirm from the implants and hence a second surgery is required will remove those implant material. One approach to managing the discharge of toxic metal ions is to coat the implant substance with bio-mimetic minerals in hydroxyapatite (HA). Bio-mimetic minerals such as magnesium (Mg), strontium (Sr), also zinc (Zn) were revealed with animate bone growth furthermore restrain bone resorption both in vitro and in vivo. The present work deals with the electrophoretic deposition (EPD) for multi minerals substituted hydroxyapatite (M-HA) on the surface treated 316L SS under distinctive temperatures (27°C, (room temperature), 60 and 80°C). The resultant coatings were characterized by FT-IR, XRD, SEM-EDX, adhesion strength and leach out analysis.

  9. Study of 13Cr-4Ni-(Mo (F6NM Steel Grade Heat Treatment for Maximum Hardness Control in Industrial Heats

    Directory of Open Access Journals (Sweden)

    Massimo De Sanctis

    2017-09-01

    Full Text Available The standard NACE MR0175 (ISO 15156 requires a maximum hardness value of 23 HRC for 13Cr-4Ni-(Mo steel grade for sour service, requiring a double tempering heat treatment at temperature in the range 648–691 °C for the first tempering and 593–621 °C for the second tempering. Difficulties in limiting alloy hardness after the tempering of forged mechanical components (F6NM are often faced. Variables affecting the thermal behavior of 13Cr-4Ni-(Mo during single and double tempering treatments have been studied by means of transmission electron microscopy (TEM observations, X-ray diffraction measurements, dilatometry, and thermo-mechanical simulations. It has been found that relatively low Ac1 temperatures in this alloy induce the formation of austenite phase above 600 °C during tempering, and that the formed, reverted austenite tends to be unstable upon cooling, thus contributing to the increase of final hardness via transformation to virgin martensite. Therefore, it is necessary to increase the Ac1 temperature as much as possible to allow the tempering of martensite at the temperature range required by NACE without the detrimental formation of virgin martensite upon final cooling. Attempts to do so have been carried out by reducing both carbon (<0.02% C and nitrogen (<100 ppm levels. Results obtained herein show final hardness below NACE limits without an unacceptable loss of mechanical strength.

  10. Development of strontium and magnesium substituted porous hydroxyapatite/poly(3,4-ethylenedioxythiophene) coating on surgical grade stainless steel and its bioactivity on osteoblast cells.

    Science.gov (United States)

    Gopi, D; Ramya, S; Rajeswari, D; Surendiran, M; Kavitha, L

    2014-02-01

    The present study deals with the successful development of bilayer coatings by electropolymerisation of poly(3,4-ethylenedioxythiophene) (PEDOT) on surgical grade stainless steel (316L SS) followed by the electrodeposition of strontium (Sr) and magnesium (Mg) substituted porous hydroxyapatite (Sr, Mg-HA). The bilayer coatings were characterised by Fourier transform infrared spectroscopy (FT-IR) and high resolution scanning electron microscopy (HRSEM). Corrosion resistance of the obtained coatings was investigated in Ringer's solution by electrochemical techniques and the results were in good agreement with those obtained from chemical analysis, namely inductively coupled plasma atomic emission spectrometry (ICP-AES). Also, the mechanical and biological properties of the bilayer coatings were analyzed. From the obtained results it was evident that the PEDOT/Sr, Mg-HA bilayer exhibited greater adhesion strength than the Sr, Mg-HA coated 316L SS. In vitro cell adhesion test of the Sr, Mg-HA coating on PEDOT coated specimen is found to be more bioactive compared to that of the single substituted hydroxyapatite (Sr or Mg-HA) on the PEDOT coated 316L SS. Thus, the PEDOT/Sr, Mg-HA bilayer coated 316L SS can serve as a prospective implant material for biomedical applications. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Corrosion of stainless steel grades in molten NaOH/KOH eutectic at 250 C: AISI304 austenitic and 2205 duplex

    Energy Technology Data Exchange (ETDEWEB)

    Bozzini, B.; Bogani, F.; Scarselli, G. [Dipartimento di Ingegneria dell' Innovazione, Universita del Salento, Via per Monteroni, 73100 Lecce (Italy); Barella, S.; Boniardi, M. [Dipartimento di Meccanica, Politecnico di Milano, via La Masa 34, 20156 Milano (Italy); Giovannelli, G.; Natali, S. [Dipartimento DICMA, Universita di Roma ' ' La Sapienza' ' , via Eudossiana 18, 00184 Roma (Italy)

    2012-11-15

    The present paper focuses on the corrosion of an austenitic (AISI304) and a duplex (2205) stainless steel grade in molten KOH/NaOH 50 w/o eutectic at 250 C. Experimental activities have been performed consisting in electrochemical measurements (linear sweep voltammetry and electrochemical impedance spectrometry) complemented by metallographic (in-plane and cross-sectional SEM micrography), structural (X-ray diffractometry) and compositional (EDX line-profiles) characterisation of the materials attacked under electrochemically controlled conditions. Electrochemical measurements have shown that AISI304 exhibits a passivating behaviour, characterised by two passivation peaks and a transpassive threshold, while duplex, does not yield a clear indication of passivation. AISI304 was found to fail by intergranular corrosion and to be covered in both passive and transpassive conditions, by an incoherent scale, containing electrolyte species. Duplex samples, instead tends to fail by homogeneous attack and exhibit a range of scale structures, depending on the applied potential. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. Role of Chloride in the Corrosion and Fracture Behavior of Micro-Alloyed Steel in E80 Simulated Fuel Grade Ethanol Environment

    Directory of Open Access Journals (Sweden)

    Olufunmilayo O. Joseph

    2016-06-01

    Full Text Available In this study, micro-alloyed steel (MAS material normally used in the production of auto parts has been immersed in an E80 simulated fuel grade ethanol (SFGE environment and its degradation mechanism in the presence of sodium chloride (NaCl was evaluated. Corrosion behavior was determined through mass loss tests and electrochemical measurements with respect to a reference test in the absence of NaCl. Fracture behavior was determined via J-integral tests with three-point bend specimens at an ambient temperature of 27 °C. The mass loss of MAS increased in E80 with NaCl up to a concentration of 32 mg/L; beyond that threshold, the effect of increasing chloride was insignificant. MAS did not demonstrate distinct passivation behavior, as well as pitting potential with anodic polarization, in the range of the ethanol-chloride ratio. Chloride caused pitting in MAS. The fracture resistance of MAS reduced in E80 with increasing chloride. Crack tip blunting decreased with increasing chloride, thus accounting for the reduction in fracture toughness.

  13. Effect of Long-Term Thermal Exposures on Microstructure and Impression Creep in 304HCu Grade Austenitic Stainless Steel

    Science.gov (United States)

    Dash, Manmath Kumar; Karthikeyan, T.; Mythili, R.; Vijayanand, V. D.; Saroja, S.

    2017-10-01

    This paper presents the results of microstructural evolution and mechanical properties in 304H Cu grade austenite stainless (SS 304HCu) during long-term exposure at high temperatures. The predicted phase composition as a function of temperature obtained using JMatPro® software was confirmed in conjunction with the microstructural evolution characterized by scanning and transmission electron microscopy. Microstructures revealed primary Nb(C,N), M23C6 precipitates at γ-grain boundaries, fine secondary Nb(C,N) intragranular carbides, and a uniform precipitation of <40-nm-sized spherical Cu-rich phase after thermal aging for 10,000 hours at 903 K (630 °C). The impression creep rate at 300 MPa increased by a factor of 20 between 873 K and 923 K (600 °C and 650 °C). The creep rate at 903 K (630 °C) was found to moderately reduce with aging time, signifying the role of Cu-rich phase in improving the creep resistance. The deformation zones and the recrystallization behavior of the plastic zone in creep tested specimen was assessed using Electron backscatter diffraction technique.

  14. The influence of surface microstructure and chemical composition on corrosion behaviour in fuel-grade bio-ethanol of low-alloy steel modified by plasma nitro-carburizing and post-oxidizing

    Science.gov (United States)

    Boniatti, Rosiana; Bandeira, Aline L.; Crespi, Ângela E.; Aguzzoli, Cesar; Baumvol, Israel J. R.; Figueroa, Carlos A.

    2013-09-01

    The interaction of bio-ethanol on steel surfaces modified by plasma-assisted diffusion technologies is studied for the first time. The influence of surface microstructure and chemical composition on corrosion behaviour of AISI 4140 low-alloy steel in fuel-grade bio-ethanol was investigated. The steel surfaces were modified by plasma nitro-carburizing followed plasma oxidizing. X-ray diffraction, scanning electron microscopy, optical microscopy, X-ray dispersive spectroscopy, and glow-discharge optical emission spectroscopy were used to characterize the modified surface before and after immersion tests in bio-ethanol up to 77 days. The main corrosion mechanism is pit formation. The pit density and pit size were measured in order to quantify the corrosion resistance which was found to depend more strongly on microstructure and morphology of the oxide layer than on its thickness. The best corrosion protection was observed for samples post-oxidized at 480 °C and 90 min.

  15. The influence of surface microstructure and chemical composition on corrosion behaviour in fuel-grade bio-ethanol of low-alloy steel modified by plasma nitro-carburizing and post-oxidizing

    International Nuclear Information System (INIS)

    Boniatti, Rosiana; Bandeira, Aline L.; Crespi, Ângela E.; Aguzzoli, Cesar; Baumvol, Israel J.R.; Figueroa, Carlos A.

    2013-01-01

    The interaction of bio-ethanol on steel surfaces modified by plasma-assisted diffusion technologies is studied for the first time. The influence of surface microstructure and chemical composition on corrosion behaviour of AISI 4140 low-alloy steel in fuel-grade bio-ethanol was investigated. The steel surfaces were modified by plasma nitro-carburizing followed plasma oxidizing. X-ray diffraction, scanning electron microscopy, optical microscopy, X-ray dispersive spectroscopy, and glow-discharge optical emission spectroscopy were used to characterize the modified surface before and after immersion tests in bio-ethanol up to 77 days. The main corrosion mechanism is pit formation. The pit density and pit size were measured in order to quantify the corrosion resistance which was found to depend more strongly on microstructure and morphology of the oxide layer than on its thickness. The best corrosion protection was observed for samples post-oxidized at 480 °C and 90 min.

  16. USAJOBS Job Opportunity Announcements (JOA) REST API

    Data.gov (United States)

    Office of Personnel Management — This REST-based API is designed to support lightweight Federal Job Opportunity Announcement (JOA) content consumption by consumers. It is anticipated that this API...

  17. USAJOBS Job Opportunity Announcements (JOA) SOAP API

    Data.gov (United States)

    Office of Personnel Management — The purpose of the SOAP based API is to provide the full Federal Job Opportunity Announcement (JOA) content to the consumer. It is anticipated that this API will be...

  18. An evaluation procedure of sodium environmental effects on FBR grade SUS316 (316FR) and Modified 9Cr-1Mo steel. On the basis of the studies up to the fiscal year of 1998

    International Nuclear Information System (INIS)

    1999-01-01

    Evaluation of sodium environmental effects on structural materials of fast breeder reactors (FBR's) is one of the key issues for the integrity of the plants. The Elevated Temperature Structural Design Guide for Monju (ETSDG) incorporated an evaluation procedure of sodium environmental effects in the Appendix MA.2, for the conventional steels, such as SUS304, SUS316, SUS321 and 2 1/4Cr-1Mo. Following the establishment of the ETSDG, a new material with superior elevated temperature properties, FBR grade SUS316 (316FR), has been developed, and studies on Mod.9Cr-1Mo steel (Mod.9Cr-1Mo steel) has been performed, for the application to demonstration reactors and successive large-scale reactors. These materials were shown to have, at least equal, or better compatibility with sodium compared with the conventional steels. Moreover, studies have been continued with the conventional steels, particularly with SUS304, for the further validation of the procedure in the ETSDG, especially in terms of long-term properties. Those studies provide basis for the study on 316FR. This report proposed an evaluation procedure of sodium environmental effects on 316FR and Mod.9Cr-1Mo steel, which is to be incorporated into the structural design guide for demonstration fast breeder reactors. The procedure is summarized as follows: (1) Corrosion allowance of 316FR and Mod.9Cr-1Mo can be evaluated by the equation determined in the ETSTG. (2) Strength reduction factors on design allowable values are not necessary for either steel. Strength reduction due to the transfer of carbon and nitrogen, etc does not occur with 316FR, which was the same as SUS304. Mod.9Cr-1Mo steel does not show strength reduction, contrary to 2 l/4Cr-1Mo, similar ferritic steel. (3) Corrosion allowance can be determined separately for thin-walled components. The procedure allows design without correction factors for Mod.9Cr-1Mo steel, which was not possible for 2 1/4Cr-1Mo steel in the ETSDG. (author)

  19. The Web as an API.

    Energy Technology Data Exchange (ETDEWEB)

    Roman, J. H. (Jorge H.)

    2001-01-01

    As programmers we have worked with many Application Development Interface API development kits. They are well suited for interaction with a particular system. A vast source of information can be made accessible by using the http protocol through the web as an API. This setup has many advantages including the vast knowledge available on setting web servers and services. Also, these tools are available on most hardware and operating system combinations. In this paper I will cover the various types of systems that can be developed this way, their advantages and some drawbacks of this approach. Index Terms--Application Programmer Interface, Distributed applications, Hyper Text Transfer Protocol, Web.

  20. Restful API Architecture Based on Laravel Framework

    Science.gov (United States)

    Chen, Xianjun; Ji, Zhoupeng; Fan, Yu; Zhan, Yongsong

    2017-10-01

    Web service has been an industry standard tech for message communication and integration between heterogeneous systems. RESTFUL API has become mainstream web service development paradigm after SOAP, how to effectively construct RESTFUL API remains a research hotspots. This paper presents a development model of RESTFUL API construction based on PHP language and LARAVEL framework. The key technical problems that need to be solved during the construction of RESTFUL API are discussed, and implementation details based on LARAVEL are given.

  1. Effect of weld metal properties on fatigue crack growth behaviour of gas tungsten arc welded AISI 409M grade ferritic stainless steel joints

    International Nuclear Information System (INIS)

    Shanmugam, K.; Lakshminarayanan, A.K.; Balasubramanian, V.

    2009-01-01

    The effect of filler metals such as austenitic stainless steel, ferritic stainless steel and duplex stainless steel on fatigue crack growth behaviour of the gas tungsten arc welded ferritic stainless steel joints was investigated. Rolled plates of 4 mm thickness were used as the base material for preparing single 'V' butt welded joints. Centre cracked tensile (CCT) specimens were prepared to evaluate fatigue crack growth behaviour. Servo hydraulic controlled fatigue testing machine was used to evaluate the fatigue crack growth behaviour of the welded joints. From this investigation, it was found that the joints fabricated by duplex stainless steel filler metal showed superior fatigue crack growth resistance compared to the joints fabricated by austenitic and ferritic stainless steel filler metals. Higher yield strength, hardness and relatively higher toughness may be the reasons for superior fatigue performance of the joints fabricated by duplex stainless steel filler metal.

  2. Evaluation of creep damage due to stress relaxation in SA533 grade B class 1 and SA508 class 3 pressure vessel steels

    International Nuclear Information System (INIS)

    Hoffmann, C.L.; Urko, W.

    1993-01-01

    Creep damage can result from stress relaxation of residual stresses in components when exposed to high temperature thermal cycles. Pressure vessels, such as the reactor vessel of the modular high-temperature gas reactor (MHTGR), which normally operate at temperatures well below the creep range can develop relatively high residual stresses in high stress locations. During short term excursions to elevated-temperatures, creep damage can be produced by the loadings on the vessel. In addition, residual stresses will relax out, causing greater creep damage in the pressure vessel material than might otherwise be calculated. The evaluation described in this paper assesses the magnitude of the creep damage due to relaxation of residual stresses resulting from short term exposure of the pressure vessel material to temperatures in the creep range. Creep relaxation curves were generated for SA533 Grade B, Class 1 and SA508 Class 3 pressure vessel steels using finite element analysis of a simple uniaxial truss loaded under constant strain conditions to produce an initial axial stress equal to 1.25 times the material yield strength at temperature. The strain is held constant for 1000 hours at prescribed temperatures from 700 F to 1000 F. The material creep law is used to calculate the relaxed stress for each time increment. The calculated stress relaxation versus time curves are compared with stress relaxation test data. Creep damage fractions are calculated by integrating the stress relaxation versus time curves and performing a linear creep damage summation using the minimum stress to rupture curves at the respective relaxation temperatures. Cumulative creep damage due to stress relaxation as a function of time and temperature is derived from the linear damage summation

  3. Application of the Materials-by-Design Methodology to Redesign a New Grade of the High-Strength Low-Alloy Class of Steels with Improved Mechanical Properties and Processability

    Science.gov (United States)

    Grujicic, M.; Snipes, J. S.; Ramaswami, S.

    2016-01-01

    An alternative to the traditional trial-and-error empirical approach for the development of new materials is the so-called materials-by-design approach. Within the latter approach, a material is treated as a complex system and its design and optimization is carried out by employing computer-aided engineering analyses, predictive tools, and available material databases. In the present work, the materials-by-design approach is utilized to redesign a grade of high-strength low-alloy (HSLA) class of steels with improved mechanical properties (primarily strength and fracture toughness), processability (e.g., castability, hot formability, and weldability), and corrosion resistance. Toward that end, a number of material thermodynamics, kinetics of phase transformations, and physics of deformation and fracture computational models and databases have been developed/assembled and utilized within a multi-disciplinary, two-level material-by-design optimization scheme. To validate the models, their prediction is compared against the experimental results for the related steel HSLA100. Then the optimization procedure is employed to determine the optimal chemical composition and the tempering schedule for a newly designed grade of the HSLA class of steels with enhanced mechanical properties, processability, and corrosion resistance.

  4. The effect of equal channel angular pressing on the tensile properties and microstructure of two medical implant materials: ASTM F-138 austenitic steel and Grade 2 titanium

    Science.gov (United States)

    Mendes Filho, A. de A.; Sordi, V. L.; Kliauga, A. M.; Ferrante, M.

    2010-07-01

    Titanium and F-138 stainless steel are employed in bone replacement and repair. The former material was ECAP-deformed at room temperature and at 300°C, followed in some cases by cold rolling. The steel was ECAP-deformed at room temperature only. Work-hardening behavior was studied by making use of the Kocks-mecking plots and microstructural evolution was followed by TEM. Conclusions show that for Ti, ECAP combined with cold rolling gives the best strength-ductility combination, whilst room temperature ECAP increases the tensile strength of the steel but caused substantial ductility loss.

  5. The effect of equal channel angular pressing on the tensile properties and microstructure of two medical implant materials: ASTM F-138 austenitic steel and Grade 2 titanium

    Energy Technology Data Exchange (ETDEWEB)

    Filho, A de A Mendes; Sordi, V L; Kliauga, A M; Ferrante, M, E-mail: ferrante@ufscar.b [Federal University of Sao Carlos, Materials Engineering Department, Sao Carlos, 13565-905 (Brazil)

    2010-07-01

    Titanium and F-138 stainless steel are employed in bone replacement and repair. The former material was ECAP-deformed at room temperature and at 300{sup 0}C, followed in some cases by cold rolling. The steel was ECAP-deformed at room temperature only. Work-hardening behavior was studied by making use of the Kocks-mecking plots and microstructural evolution was followed by TEM. Conclusions show that for Ti, ECAP combined with cold rolling gives the best strength-ductility combination, whilst room temperature ECAP increases the tensile strength of the steel but caused substantial ductility loss.

  6. Recent advances in the API quality program

    International Nuclear Information System (INIS)

    Gollhofer, F.R.

    1991-01-01

    The API now has more than 3 years' operating experience in licensing manufacturers under the API Quality Program. The API evaluation procedures, described in this paper, provide consistency in evaluation and should allow full participation of petroleum equipment suppliers in the worldwide market during the 1990's and into the 21st century. The program's flexibility will allow it to cope with significant changes resulting from the planned European Common Market's Global Approach to Certification and Testing scheduled to occur in 1992

  7. Creep and microstructural processes in a low-alloy 2.25%Cr1.6%W steel (ASTM Grade 23)

    Czech Academy of Sciences Publication Activity Database

    Kuchařová, Květa; Sklenička, Václav; Kvapilová, Marie; Svoboda, Milan

    2015-01-01

    Roč. 109, NOV (2015), s. 1-8 ISSN 1044-5803 R&D Projects: GA TA ČR TA02010260; GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:68081723 Keywords : Bainitic steel * Low-alloy steel * Creep strength * Microstructural changes * Carbide precipitation Subject RIV: JG - Metallurgy Impact factor: 2.383, year: 2015

  8. Study of pitting corrosion in line-pipe steel under the influence of remanent magnetization

    Energy Technology Data Exchange (ETDEWEB)

    Espina-Hernandez, J H; Caleyo, F; Hallen, J M [Instituto Politecnico Nacional (IPN), Zacatenco (Mexico)

    2009-07-01

    The influence of remanent magnetization on pitting corrosion in line-pipe steels is studied. Pitting corrosion experiments have been carried out on samples of an API 5L grade 52 steel under a magnetization level of the same order of magnitude of the remanent magnetization in the pipeline wall after in-line inspection based on magnetic flux leakage. The samples were magnetized using rings of the same grade as the investigated steel. Immediately after magnetization, the investigated samples were subjected to pitting by immersing them in a solution containing dissolved Cl{sup -} and SO{sup 2-}{sub 4} and ions. The pitting experiments were conducted during a seven days period. The pit depth distribution and the maximum pit depth in each sample were recorded and used to conduct extreme value analyses of the pitting process in magnetized and non-magnetized control samples. The statistical assessment of the pitting corrosion data collected during this study shows that the magnetic field reduces the average depth of the pit population and also the extreme pit depth values that can be predicted from the maximum values observed in the magnetized samples in comparison with to the non-magnetized control samples. Scanning electron microscopy observations show that the magnetic field alters the pit morphology by increasing the pit mouth opening. (author)

  9. Validation of the Parlay API through prototyping

    NARCIS (Netherlands)

    Hellenthal, J.W.; Planken, F.J.M.; Wegdam, M.

    2001-01-01

    The desire within the telecommunications world for new and faster business growth has been a major drive towards the development of open network API. Over the past 7 years several (semi) standardization groups have announced work on network API, including TINA-C, JAIN, IEEE P1520, INforum, 3GPP,

  10. Resolution and sensitivity of the eyes of the Asian honeybees Apis florea, Apis cerana and Apis dorsata.

    Science.gov (United States)

    Somanathan, Hema; Warrant, Eric J; Borges, Renee M; Wallén, Rita; Kelber, Almut

    2009-08-01

    Bees of the genus Apis are important foragers of nectar and pollen resources. Although the European honeybee, Apis mellifera, has been well studied with respect to its sensory abilities, learning behaviour and role as pollinators, much less is known about the other Apis species. We studied the anatomical spatial resolution and absolute sensitivity of the eyes of three sympatric species of Asian honeybees, Apis cerana, Apis florea and Apis dorsata and compared them with the eyes of A. mellifera. Of these four species, the giant honeybee A. dorsata (which forages during moonlit nights) has the lowest spatial resolution and the most sensitive eyes, followed by A. mellifera, A. cerana and the dwarf honeybee, A. florea (which has the smallest acceptance angles and the least sensitive eyes). Moreover, unlike the strictly diurnal A. cerana and A. florea, A. dorsata possess large ocelli, a feature that it shares with all dim-light bees. However, the eyes of the facultatively nocturnal A. dorsata are much less sensitive than those of known obligately nocturnal bees such as Megalopta genalis in Panama and Xylocopa tranquebarica in India. The differences in sensitivity between the eyes of A. dorsata and other strictly diurnal Apis species cannot alone explain why the former is able to fly, orient and forage at half-moon light levels. We assume that additional neuronal adaptations, as has been proposed for A. mellifera, M. genalis and X. tranquebarica, might exist in A. dorsata.

  11. Evidence of Apis cerana Sacbrood virus Infection in Apis mellifera.

    Science.gov (United States)

    Gong, Hong-Ri; Chen, Xiu-Xian; Chen, Yan Ping; Hu, Fu-Liang; Zhang, Jiang-Lin; Lin, Zhe-Guang; Yu, Ji-Wei; Zheng, Huo-Qing

    2016-04-01

    Sacbrood virus(SBV) is one of the most destructive viruses in the Asian honeybee Apis cerana but is much less destructive in Apis mellifera In previous studies, SBV isolates infecting A. cerana(AcSBV) and SBV isolates infecting A. mellifera(AmSBV) were identified as different serotypes, suggesting a species barrier in SBV infection. In order to investigate this species isolation, we examined the presence of SBV infection in 318A. mellifera colonies and 64A. cerana colonies, and we identified the genotypes of SBV isolates. We also performed artificial infection experiments under both laboratory and field conditions. The results showed that 38A. mellifera colonies and 37A. cerana colonies were positive for SBV infection. Phylogenetic analysis based on RNA-dependent RNA polymerase (RdRp) gene sequences indicated that A. cerana isolates and most A. mellifera isolates formed two distinct clades but two strains isolated fromA. mellifera were clustered with theA. cerana isolates. In the artificial-infection experiments, AcSBV negative-strand RNA could be detected in both adult bees and larvae ofA. mellifera, although there were no obvious signs of the disease, demonstrating the replication of AcSBV inA. mellifera Our results suggest that AcSBV is able to infectA. melliferacolonies with low prevalence (0.63% in this study) and pathogenicity. This work will help explain the different susceptibilities ofA. cerana and A. melliferato sacbrood disease and is potentially useful for guiding beekeeping practices. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  12. Development of an API 5 L X 70 coil for the production of API pipes continuously welded by electric resistance; Desenvolvimento de bobina API 5 L X 70 para producao de tubos API soldados continuamente por resistencia eletrica

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Alexandre R; Cavalheiro, Benedito C [CONFAB Tubos S.A., Sao Caetano do Sul, SP (Brazil)

    1998-07-01

    The manufacturing of high strength ERW pipe, which applies the continuous forming process, is known to lead to a relevant economy in a productivity basis. The past few years shown a trend of changing on grade range, from the past X52 to the present X70. The manufacturing of the latter grades for coils are somehow difficult due to the high Bauschinger effect observed on ERW pipes with ferritic-perlitic microstructure, that results in pipes with yield strength much lower than in coils, as on limitations on rolling, where controlled rolling is not applied. In this work, acicular dispersed bainite was searched, in a way to reduce this effect after pipe forming. API 5L X70 coils, from USIMINAS, were processed including an intentional addition of Molybdenum in the range of 0.20%, together with Columbium and Vanadium (added as 0.050% average). (author)

  13. Full-scale locomotive dynamic crash testing and correlations : locomotive consist colliding with steel coil truck at grade crossing (test 3).

    Science.gov (United States)

    2011-09-01

    This report presents the test results and finite element correlations of a full-scale dynamic collision between a locomotive and a highway truck loaded with two heavy steel coils. The locomotive consist was moving at 58 miles per hour before it struc...

  14. On choice of tempered steels

    International Nuclear Information System (INIS)

    Govorov, A.A.; Pan'shin, I.F.; Rakhmanov, V.I.

    1978-01-01

    For the purpose of developing a graphical method for choosing structural steels, a change in the propagation work of a crack and in the critical temperature of brittleness of 40, 40Kh, 40KhN, and 40KhNM steels, was examined depending on the hardness after hardening and tempering. A diagram enabling to choose the grade of steel for making an article of known dimensions according to the preset values of its mechanical properties has been plotted. The developed selection scheme takes into account the hardenability of steels and the influence of the hardness after thermal treatment on the cold-shortness of steel

  15. Estudo do efeito da tensão sobre a permeação por Hidrogênio em Aços API 5L X60 e API 5L X65

    Directory of Open Access Journals (Sweden)

    Bruno Araújo Araújo

    2017-12-01

    Full Text Available Under operating conditions, the oil and gas transmission pipelines can be subjected to high pressures and, at the same time, suffer the effect of acidic substances in the transported hydrocarbons such as H2S, whose action alone or combined with stresses acting in the structure can cause degradation processes of the mechanical properties of the material. Given the importance of the phenomenon, this work has as main objective the realization of hydrogen electrochemical permeation tests in API 5L X60 and API 5L X65 steels under mechanical loading conditions. A device for performing electrochemical permeation tests of hydrogen in the specimens subjected to stress was used for the tests. Thus, it was possible to observe experimentally the influence of stress on the diffusion properties during the experiment. By applying stress on the order of 20% of the yield strength, it was possible to verify the increase of diffusivity of API 5L X60 steel. Furthermore, there was a strong influence of the stress level of permeability, because a large increase of permeability of API 5L X65 steel. The results indicate that the lattice deformation due to imposed mechanical stress has a great influence on the diffusion properties of materials

  16. Influence of preheating on API 5L-X80 pipeline joint welding with self shielded flux-cored wire

    International Nuclear Information System (INIS)

    Cooper, R.; Silva, J. H. F.; Trevisan, R. E.

    2004-01-01

    The present work refers to the characterization of API 5L-X80 pipeline joints welded with self-shielded flux cored wire. This process was evaluated under preheating conditions, with an uniform and steady heat input. All joints were welded in flat position (1G), with the pipe turning and the torch still. Tube dimensions were 762 mm in external diameter and 16 mm in thickness. Welds were applied on single V-groove, with six weld beads, along with three levels of preheating temperatures (room temperature, 100 degree centigree, 160 degree centigree). These temperatures were maintained as inter pass temperature. The filler metal E71T8-K6 with mechanical properties different from parent metal was used in under matched conditions. The weld characterization is presented according to the mechanical test results of tensile strength, hardness and impact test. The mechanical tests were conducted according to API 1104, AWS and ASTM standards. API 1104 and API 51 were used as screening criteria. According to the results obtained, it was possible to remark that it is appropriate to weld API 5L-X80 steel ducts with Self-shielded Flux Cored wires, in conformance to the API standards and no preheat temperature is necessary. (Author) 22 refs

  17. Web API Growing Pains : Loosely Coupled yet Strongly Tied

    NARCIS (Netherlands)

    Espinha, T.; Zaidman, A.; Gross, H.G.

    2014-01-01

    Web APIs provide a systematic and extensible approach for application-toapplication interaction. Developers using web APIs are forced to accompany the API providers in their software evolution tasks. In order to understand the distress caused by this imposition on web API client developers we

  18. The JANA calibrations and conditions database API

    International Nuclear Information System (INIS)

    Lawrence, David

    2010-01-01

    Calibrations and conditions databases can be accessed from within the JANA Event Processing framework through the API defined in its JCalibration base class. The API is designed to support everything from databases, to web services to flat files for the backend. A Web Service backend using the gSOAP toolkit has been implemented which is particularly interesting since it addresses many modern cybersecurity issues including support for SSL. The API allows constants to be retrieved through a single line of C++ code with most of the context, including the transport mechanism, being implied by the run currently being analyzed and the environment relieving developers from implementing such details.

  19. The JANA calibrations and conditions database API

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence, David, E-mail: davidl@jlab.or [12000 Jefferson Ave., Suite 8, Newport News, VA 23601 (United States)

    2010-04-01

    Calibrations and conditions databases can be accessed from within the JANA Event Processing framework through the API defined in its JCalibration base class. The API is designed to support everything from databases, to web services to flat files for the backend. A Web Service backend using the gSOAP toolkit has been implemented which is particularly interesting since it addresses many modern cybersecurity issues including support for SSL. The API allows constants to be retrieved through a single line of C++ code with most of the context, including the transport mechanism, being implied by the run currently being analyzed and the environment relieving developers from implementing such details.

  20. DySectAPI: Scalable Prescriptive Debugging

    DEFF Research Database (Denmark)

    Jensen, Nicklas Bo; Karlsson, Sven; Quarfot Nielsen, Niklas

    We present the DySectAPI, a tool that allow users to construct probe trees for automatic, event-driven debugging at scale. The traditional, interactive debugging model, whereby users manually step through and inspect their application, does not scale well even for current supercomputers. While...... lightweight debugging models scale well, they can currently only debug a subset of bug classes. DySectAPI fills the gap between these two approaches with a novel user-guided approach. Using both experimental results and analytical modeling we show how DySectAPI scales and can run with a low overhead...

  1. Transcriptome differences in the hypopharyngeal gland between Western Honeybees (Apis mellifera) and Eastern Honeybees (Apis cerana).

    Science.gov (United States)

    Liu, Hao; Wang, Zi-Long; Tian, Liu-Qing; Qin, Qiu-Hong; Wu, Xiao-Bo; Yan, Wei-Yu; Zeng, Zhi-Jiang

    2014-08-30

    Apis mellifera and Apis cerana are two sibling species of Apidae. Apis cerana is adept at collecting sporadic nectar in mountain and forest region and exhibits stiffer hardiness and acarid resistance as a result of natural selection, whereas Apis mellifera has the advantage of producing royal jelly. To identify differentially expressed genes (DEGs) that affect the development of hypopharyngeal gland (HG) and/or the secretion of royal jelly between these two honeybee species, we performed a digital gene expression (DGE) analysis of the HGs of these two species at three developmental stages (newly emerged worker, nurse and forager). Twelve DGE-tag libraries were constructed and sequenced using the total RNA extracted from the HGs of newly emerged workers, nurses, and foragers of Apis mellifera and Apis cerana. Finally, a total of 1482 genes in Apis mellifera and 1313 in Apis cerana were found to exhibit an expression difference among the three developmental stages. A total of 1417 DEGs were identified between these two species. Of these, 623, 1072, and 462 genes showed an expression difference at the newly emerged worker, nurse, and forager stages, respectively. The nurse stage exhibited the highest number of DEGs between these two species and most of these were found to be up-regulated in Apis mellifera. These results suggest that the higher yield of royal jelly in Apis mellifera may be due to the higher expression level of these DEGs. In this study, we investigated the DEGs between the HGs of two sibling honeybee species (Apis mellifera and Apis cerana). Our results indicated that the gene expression difference was associated with the difference in the royal jelly yield between these two species. These results provide an important clue for clarifying the mechanisms underlying hypopharyngeal gland development and the production of royal jelly.

  2. ChemSpell Web Service API

    Data.gov (United States)

    U.S. Department of Health & Human Services — The ChemSpell Web Service API provides chemical name spell checking and chemical name synonym look-up. ChemSpell contains more than 1.3 million chemical names...

  3. Online maps with APIs and webservices

    CERN Document Server

    Peterson, Michael P

    2014-01-01

    With the Internet now the primary method of accessing maps, this volume examines developments in the world of online map delivery, focusing in particular on application programmer interfaces such as the Google Maps API, and their utility in thematic mapping.

  4. System for Award Management (SAM) API

    Data.gov (United States)

    General Services Administration — The SAM API is a RESTful method of retrieving public information about the businesses, organizations, or individuals (referred to as entities) within the SAM entity...

  5. Real World Uses For Nagios APIs

    Science.gov (United States)

    Singh, Janice

    2014-01-01

    This presentation describes the Nagios 4 APIs and how the NASA Advanced Supercomputing at Ames Research Center is employing them to upgrade its graphical status display (the HUD) and explain why it's worth trying to use them yourselves.

  6. Why and How Java Developers Break APIs

    OpenAIRE

    Brito, Aline; Xavier, Laerte; Hora, Andre; Valente, Marco Tulio

    2018-01-01

    Modern software development depends on APIs to reuse code and increase productivity. As most software systems, these libraries and frameworks also evolve, which may break existing clients. However, the main reasons to introduce breaking changes in APIs are unclear. Therefore, in this paper, we report the results of an almost 4-month long field study with the developers of 400 popular Java libraries and frameworks. We configured an infrastructure to observe all changes in these libraries and t...

  7. Building API manufacturing in South Africa

    CSIR Research Space (South Africa)

    Loots, Glaudina

    2017-10-01

    Full Text Available projects) Challenges • Lack of relevant skills – process chemistry, process engineering (cGMP standards), project engineering, project management, process operations, maintenance and process quality control and assurance. – platform for skills... development - to enable a sustained pipeline of multidisciplinary skills for the envisaged API industry expansion. – entrepreneurial thinking – attract young talent in establishing niche businesses within the API manufacturing sector. • Small local...

  8. THE DEVELOPMENT OF TECHNOLOGY OF THE CORE THERMO-MECHANICALLY HARDENED REINFORC-ING STEEL OF GRADE A700HW OF DIE-ROLLED SECTION NO 12, 14, 16 PRODUCTION ACCORDING TO REQUIREMENT OF FINNISH STANDARDS SFST1216 IN CONDITIONS OF SMALL-SECTION MILL 320 OF RUP «BMZ»

    Directory of Open Access Journals (Sweden)

    A. V. Rusalenko

    2009-01-01

    Full Text Available The development of technology of the core thermomechanically hardened reinforcing steel of grade А700HW of die-rolled section No 12, 14, 16 production according to requirement of Finnish standards SFST1216 in conditions of small-section mill 320 of RUP «BMZ» is given.

  9. Expanded austenite in nitrided layers deposited on austenitic and super austenitic stainless steel grades; Analise da austenita expandida em camadas nitretadas em acos inoxidaveis austeniticos e superaustenitico

    Energy Technology Data Exchange (ETDEWEB)

    Casteletti, L.C.; Fernandes, F.A.P.; Heck, S.C. [Universidade de Sao Paulo (EESC/USP), Sao Carlos, SP (Brazil). Escola de Engenharia. Dept. de Engenharia de Materais, Aeronautica e Automobilistica; Oliveira, A.M. [Instituto de Educacao, Ciencia e Tecnologia do Maranhao (IFMA), Sao Luis, MA (Brazil); Gallego, J., E-mail: gallego@dem.feis.unesp.b [UNESP, Ilha Solteira, SP (Brazil). Dept. Engenharia Mecanica

    2010-07-01

    In this work nitrided layers deposited on austenitic and super austenitic stainless steels were analyzed through optical microscopy and X-rays diffraction analysis (XRD). It was observed that the formation of N supersaturated phase, called expanded austenite, has promoted significant increment of hardness (> 1000HV). XRD results have indicated the anomalous displacement of the diffracted peaks, in comparison with the normal austenite. This behavior, combined with peaks broadening, it was analyzed in different nitriding temperatures which results showed good agreement with the literature. (author)

  10. INHIBITION EFFECT OF FLAVONOID EXTRACT OF Euphorbia Guyoniana ON THE CORROSION OF MILD STEEL IN H2SO4 MEDIUM

    OpenAIRE

    S. Chihi; N. Gherraf; B. Alabed; S. Hameurlain

    2009-01-01

    The influence of flavonoids extracts of three parts of Euphorbia Guyoniana towards the corrosion of type API 5L X52 steel in 15% H2SO4 has been evaluated by weight loss method and polarization technique. The results showed that extracts are a good inhibitors for API 5L X52 steel in this medium. The corrosion inhibition efficiency increases on increasing plant extracts concentration. The inhibition is attributed to the adsorption of the surface of the metal. Potentiodynamic polarization result...

  11. Effect of Reheating Temperature and Cooling Treatment on the Microstructure, Texture, and Impact Transition Behavior of Heat-Treated Naval Grade HSLA Steel

    Science.gov (United States)

    Sk, Md. Basiruddin; Ghosh, A.; Rarhi, N.; Balamuralikrishnan, R.; Chakrabarti, D.

    2017-07-01

    In order to achieve the desired mechanical properties [YS > 390 MPa, total elongation >16 pct and Charpy impact toughness of 78 J at 213 K (-60 °C)] for naval application, samples from a low-carbon microalloyed steel have been subjected to different austenitization (1223 K to 1523 K) (950 °C to 1250 °C) and cooling treatments (furnace, air, or water cooling). The as-rolled steel and the sample air cooled from 1223 K (950 °C) could only achieve the required tensile properties, while the sample furnace cooled from 1223 K (950 °C) showed the best Charpy impact properties. Water quenching from 1223 K (950 °C) certainly contributed to the strength but affected the impact toughness. Overall, predominantly ferrite matrix with fine effective grain size and intense gamma-fiber texture was found to be beneficial for impact toughness as well as impact transition behavior. Small size and fraction of precipitates (like TiN, Nb, and V carbonitrides) eliminated the possibility of particle-controlled crack propagation and grain size-controlled crack propagation led to cleavage fracture. A simplified analytical approach has been used to explain the difference in impact transition behavior of the investigated samples.

  12. Microstructure Evolution and Mechanical Properties of Underwater Dry and Local Dry Cavity Welded Joints of 690 MPa Grade High Strength Steel.

    Science.gov (United States)

    Shi, Yonghua; Sun, Kun; Cui, Shuwan; Zeng, Min; Yi, Jianglong; Shen, Xiaoqin; Yi, Yaoyong

    2018-01-22

    Q690E high strength low alloy (HSLA) steel plays an important role in offshore structures. In addition, underwater local cavity welding (ULCW) technique was widely used to repair important offshore constructions. However, the high cooling rate of ULCW joints results in bad welding quality compared with underwater dry welding (UDW) joints. Q690E high strength low alloy steels were welded by multi-pass UDW and ULCW techniques, to study the microstructural evolution and mechanical properties of underwater welded joints. The microstructure and fracture morphology of welded joints were observed by scanning electron microscope and optical microscope. The elemental distribution in the microstructure was determined with an Electron Probe Microanalyzer. The results indicated that the microstructure of both two welded joints was similar. However, martensite and martensite-austenite components were significantly different with different underwater welding methods such that the micro-hardness of the HAZ and FZ in the ULCW specimen was higher than that of the corresponding regions in UDW joint. The yield strength and ultimate tensile strength of the ULCW specimen are 109 MPa lower and 77 MPa lower, respectively, than those of the UDW joint. The impact toughness of the UDW joint was superior to those of the ULCW joint.

  13. Microstructure Evolution and Mechanical Properties of Underwater Dry and Local Dry Cavity Welded Joints of 690 MPa Grade High Strength Steel

    Science.gov (United States)

    Sun, Kun; Cui, Shuwan; Zeng, Min; Yi, Jianglong; Shen, Xiaoqin; Yi, Yaoyong

    2018-01-01

    Q690E high strength low alloy (HSLA) steel plays an important role in offshore structures. In addition, underwater local cavity welding (ULCW) technique was widely used to repair important offshore constructions. However, the high cooling rate of ULCW joints results in bad welding quality compared with underwater dry welding (UDW) joints. Q690E high strength low alloy steels were welded by multi-pass UDW and ULCW techniques, to study the microstructural evolution and mechanical properties of underwater welded joints. The microstructure and fracture morphology of welded joints were observed by scanning electron microscope and optical microscope. The elemental distribution in the microstructure was determined with an Electron Probe Microanalyzer. The results indicated that the microstructure of both two welded joints was similar. However, martensite and martensite-austenite components were significantly different with different underwater welding methods such that the micro-hardness of the HAZ and FZ in the ULCW specimen was higher than that of the corresponding regions in UDW joint. The yield strength and ultimate tensile strength of the ULCW specimen are 109 MPa lower and 77 MPa lower, respectively, than those of the UDW joint. The impact toughness of the UDW joint was superior to those of the ULCW joint. PMID:29361743

  14. Structure–property relationship in a 960 MPa grade ultrahigh strength low carbon niobium–vanadium microalloyed steel: The significance of high frequency induction tempering

    International Nuclear Information System (INIS)

    Xie, Z.J.; Fang, Y.P.; Han, G.; Guo, H.; Misra, R.D.K.; Shang, C.J.

    2014-01-01

    The present study describes the microstructure and precipitation behavior in an ultra-high strength low carbon niobium–vanadium microalloyed steel that was processed by quenching and high frequency induction tempering. Ultrahigh yield strength of ∼1000 MPa with high elongation of ∼15% and high low temperature toughness of 55 J (half thickness) at −40 °C was obtained after quenching from austenitization at 900 °C for 30 min, and tempering at 600 °C for 15 min by induction reheating with a reheating rate of ∼50 °C/s. While the yield strength increase on tempering was similar for both induction reheating and conventional reheating (electrical resistance reheating), there was ∼100% increase in low temperature toughness in induction reheated steel compared to the conventional reheating process. The underlying reason for the increase in toughness was attributed to the transformation of cementite film observed in conventional reheating and tempering to nanoscale cementite in induction reheating and tempering. The precipitation of nanoscale carbides is believed to significantly contribute to ultra-high strength, good ductility, and high toughness in the high frequency induction reheating and tempering process

  15. APIs and Researchers: The Emperor's New Clothes?

    Directory of Open Access Journals (Sweden)

    Jennifer Edmond

    2015-02-01

    Full Text Available As part of the Europeana Cloud (eCloud project, Trinity College Dublin investigated best practice in the use of web services, such as APIs, for accessing large data sets from cultural heritage collections. This research looked into the provision and use of APIs, and moreover, whether or not more customised programmatic access to datasets is what researchers want or need. In order to understand whether current patterns of API usage reflect a skills gap on the part of researchers or a mismatch of tool to purpose, we looked not only at the creators and developer/users of APIs, but also at humanists already re-using big data; approaches in cultural heritage institutions and other research infrastructures to bring API use to non-technical audiences; and the kinds of training and other support services available or emerging within the data-intensive humanities research lifecycle. We conducted both desk research and a series of 11 interviews with figures working as researchers, developers or data providers, including figures from both the API development and the data usage communities. This research, conducted under the eCloud project and supported by the European Commission’s ICT Policy and Support Programme (Grant number 325091, was begun in March 2014 and is now in its concluding validation stage. The results of the research are not yet finalised, but the contribution is already emerging of this work to the debate about APIs being either the way forward for digital cultural heritage collections, or the Emperor’s New Clothes (or maybe a bit of both.

  16. The putative serine protease inhibitor Api m 6 from Apis mellifera venom: recombinant and structural evaluation.

    Science.gov (United States)

    Michel, Y; McIntyre, M; Ginglinger, H; Ollert, M; Cifuentes, L; Blank, S; Spillner, E

    2012-01-01

    Immunoglobulin (Ig) E-mediated reactions to honeybee venom can cause severe anaphylaxis, sometimes with fatal consequences. Detailed knowledge of the allergic potential of all venom components is necessary to ensure proper diagnosis and treatment of allergy and to gain a better understanding of the allergological mechanisms of insect venoms. Our objective was to undertake an immunochemical and structural evaluation of the putative low-molecular-weight serine protease inhibitor Api m 6, a component of honeybee venom. We recombinantly produced Api m 6 as a soluble protein in Escherichia coli and in Spodoptera frugiperda (Sf9) insect cells.We also assessed specific IgE reactivity of venom-sensitized patients with 2 prokaryotically produced Api m 6 variants using enzyme-linked immunosorbent assay. Moreover, we built a structural model ofApi m 6 and compared it with other protease inhibitor structures to gain insights into the function of Api m 6. In a population of 31 honeybee venom-allergic patients, 26% showed specific IgE reactivity with prokaryotically produced Api m 6, showing it to be a minor but relevant allergen. Molecular modeling of Api m 6 revealed a typical fold of canonical protease inhibitors, supporting the putative function of this venom allergen. Although Api m 6 has a highly variant surface charge, its epitope distribution appears to be similar to that of related proteins. Api m 6 is a honeybee venom component with IgE-sensitizing potential in a fraction of venom-allergic patients. Recombinant Api m 6 can help elucidate individual component-resolved reactivity profiles and increase our understanding of immune responses to low-molecular-weight allergens

  17. FY17 Status Report on Testing Supporting the Inclusion of Grade 91 Steel as an Acceptable Material for Application of the EPP Methodology

    Energy Technology Data Exchange (ETDEWEB)

    Messner, Mark C. [Argonne National Lab. (ANL), Argonne, IL (United States); Sham, Sam [Argonne National Lab. (ANL), Argonne, IL (United States); Wang, Yanli [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-08-01

    This report summarizes the experiments performed in FY17 on Gr. 91 steels. The testing of Gr. 91 has technical significance because, currently, it is the only approved material for Class A construction that is strongly cyclic softening. Specific FY17 testing includes the following activities for Gr. 91 steel. First, two types of key feature testing have been initiated, including two-bar thermal ratcheting and Simplified Model Testing (SMT). The goal is to qualify the Elastic – Perfectly Plastic (EPP) design methodologies and to support incorporation of these rules for Gr. 91 into the ASME Division 5 Code. The preliminary SMT test results show that Gr. 91 is most damaging when tested with compression hold mode under the SMT creep fatigue testing condition. Two-bar thermal ratcheting test results at a temperature range between 350 to 650o C were compared with the EPP strain limits code case evaluation, and the results show that the EPP strain limits code case is conservative. The material information obtained from these key feature tests can also be used to verify its material model. Second, to provide experimental data in support of the viscoplastic material model development at Argonne National Laboratory, selective tests were performed to evaluate the effect of cyclic softening on strain rate sensitivity and creep rates. The results show the prior cyclic loading history decreases the strain rate sensitivity and increases creep rates. In addition, isothermal cyclic stress-strain curves were generated at six different temperatures, and a nonisothermal thermomechanical testing was also performed to provide data to calibrate the viscoplastic material model.

  18. CALIBRATION, OPTIMIZATION, AND SENSITIVITY AND UNCERTAINTY ALGORITHMS APPLICATION PROGRAMMING INTERFACE (COSU-API)

    Science.gov (United States)

    The Application Programming Interface (API) for Uncertainty Analysis, Sensitivity Analysis, and Parameter Estimation (UA/SA/PE API) tool development, here fore referred to as the Calibration, Optimization, and Sensitivity and Uncertainty Algorithms API (COSU-API), was initially d...

  19. Advanced API security securing APIs with OAuth 2.0, OpenID Connect, JWS, and JWE

    CERN Document Server

    Siriwardena, Prabath

    2014-01-01

    Advanced API Security is a complete reference to the next wave of challenges in enterprise security--securing public and private APIs. API adoption in both consumer and enterprises has gone beyond predictions. It has become the 'coolest' way of exposing business functionalities to the outside world. Both your public and private APIs, need to be protected, monitored and managed. Security is not an afterthought, but API security has evolved a lot in last five years. The growth of standards, out there, has been exponential. That's where AdvancedAPI Security comes in--to wade through the weeds

  20. Progress in the development of niobium alloyed high speed steel

    International Nuclear Information System (INIS)

    Guimaraes, J.R.C.

    1987-01-01

    The development of economy-grades of niobium alloyed high speed steel is described. Both the metallurgical concepts behind the steel design and the results of performance tests are presented. (Author) [pt

  1. A framework for API solubility modelling

    DEFF Research Database (Denmark)

    Conte, Elisa; Gani, Rafiqul; Crafts, Peter

    . In addition, most of the models are not predictive and requires experimental data for the calculation of the needed parameters. This work aims at developing an efficient framework for the solubility modelling of Active Pharmaceutical Ingredients (API) in water and organic solvents. With this framework......-SAFT) are used for solubility calculations when the needed interaction parameters or experimental data are available. The CI-UNIFAC is instead used when the previous models lack interaction parameters or when solubility data are not available. A new GC+ model for APIs solvent selection based...... on the hydrophobicity, hydrophilicity and polarity information of the API and solvent is also developed, for performing fast solvent selection and screening. Eventually, all the previous developments are integrated in a framework for their efficient and integrated use. Two case studies are presented: the first...

  2. Comparative virulence and competition between Nosema apis and Nosema ceranae in honey bees (Apis mellifera).

    Science.gov (United States)

    Milbrath, Meghan O; van Tran, Toan; Huang, Wei-Fong; Solter, Leellen F; Tarpy, David R; Lawrence, Frank; Huang, Zachary Y

    2015-02-01

    Honey bees (Apis mellifera) are infected by two species of microsporidia: Nosema apis and Nosemaceranae. Epidemiological evidence indicates that N. ceranae may be replacing N. apis globally in A. mellifera populations, suggesting a potential competitive advantage of N. ceranae. Mixed infections of the two species occur, and little is known about the interactions among the host and the two pathogens that have allowed N. ceranae to become dominant in most geographical areas. We demonstrated that mixed Nosema species infections negatively affected honey bee survival (median survival=15-17days) more than single species infections (median survival=21days and 20days for N. apis and N. ceranae, respectively), with median survival of control bees of 27days. We found similar rates of infection (percentage of bees with active infections after inoculation) for both species in mixed infections, with N. apis having a slightly higher rate (91% compared to 86% for N. ceranae). We observed slightly higher spore counts in bees infected with N. ceranae than in bees infected with N. apis in single microsporidia infections, especially at the midpoint of infection (day 10). Bees with mixed infections of both species had higher spore counts than bees with single infections, but spore counts in mixed infections were highly variable. We did not see a competitive advantage for N. ceranae in mixed infections; N. apis spore counts were either higher or counts were similar for both species and more N. apis spores were produced in 62% of bees inoculated with equal dosages of the two microsporidian species. N. ceranae does not, therefore, appear to have a strong within-host advantage for either infectivity or spore growth, suggesting that direct competition in these worker bee mid-guts is not responsible for its apparent replacement of N. apis. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Automated Ply Inspection (API) for AFP, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The Automated Ply Inspection (API) system autonomously inspects layups created by high speed automated fiber placement (AFP) machines. API comprises a high accuracy...

  4. Unified Medical Language System Terminology Services (UTS) API

    Data.gov (United States)

    U.S. Department of Health & Human Services — The UTS API is intended for application developers to perform Web service calls and retrieve UMLS data within their own applications. The UTS API provides the...

  5. Pro REST API development with nodejs

    CERN Document Server

    Doglio, Fernando

    2015-01-01

    Pro REST API Development with Node.js is your guide to managing and understanding the full capabilities of successful REST development. API design is a hot topic in the programming world, but not many resources exist for developers to really understand how you can leverage the advantages. This book will provide a brief background on REST and the tools it provides (well known and not so well known). Understand how there is more to REST than just JSON and URLs. You will then cover and compare the maintained modules currently available in the npm community, including Express, Restify, Vatican,

  6. Upon a Message-Oriented Trading API

    Directory of Open Access Journals (Sweden)

    Claudiu VINTE

    2010-01-01

    Full Text Available In this paper, we introduce the premises for a trading system application-programming interface (API based on a message-oriented middleware (MOM, and present the results of our research regarding the design and the implementation of a simulation-trading system employing a service-oriented architecture (SOA and messaging. Our research has been conducted with the aim of creating a simulation-trading platform, within the academic environment, that will provide both the foundation for future experiments with trading systems architectures, components, APIs, and the framework for research on trading strategies, trading algorithm design, and equity markets analysis tools. Mathematics Subject Classification: 68M14 (distributed systems.

  7. 47 CFR 61.46 - Adjustments to the API.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Adjustments to the API. 61.46 Section 61.46... Rules for Dominant Carriers § 61.46 Adjustments to the API. (a) Except as provided in paragraphs (d) and... carrier must calculate an API for each affected basket pursuant to the following methodology: APIt = APIt...

  8. Aircraft Steels

    Science.gov (United States)

    2009-02-19

    component usage. PH 13-8Mo is a precipitation-hardenable martensitic stainless steel combining excellent corrosion resistance with strength. Custom 465 is...a martensitic , age-hardenable stainless steel capable of about 1,724 MPa (250 ksi) UTS when peak-aged (H900 condition). Especially, this steel can...NOTES 14. ABSTRACT Five high strength steels (4340, 300M, AerMet 100, Ferrium S53, and Hy-Tuf) and four stainless steels (High Nitrogen, 13

  9. API and ISO standards can be combined

    International Nuclear Information System (INIS)

    Weightman, R.T.; Warnack, M.F.

    1992-01-01

    This paper reports that oil field equipment and product manufacturers can maintain a competitive advantage and minimize costs by integrating American Petroleum Institute (API) licensing programs with International Standards Organization (ISO) 9001 standards under one quality system. A combined quality system approach can position a company for quality system certification under ISO 9001 while maintaining API specifications. Furthermore, only one quality system manual is needed for API licensing and ISO certification, avoiding duplication of effort. The benefits of a documented quality program include the flowing: Job descriptions and personnel qualification requirements are documented; The improved documentation allows direct tracing of specific production activities; Laboratory test methods and calibration of test equipment follow accepted standards for more reliable and reproducible test data; Quality control becomes proactive, not reactive, through internal process controls previously not implemented; Employee attitudes improve through appreciation for the overall goals of the company; Ambiguous quality issues, such as documenting special customer requirements, are easily resolved; and The company image improves with customers, particularly for those that require API Specification Q1 or ISO 9001 compliance or those having their own quality performance standards

  10. CHEMICAL COMPOSITION AND ANTIOXIDANT ACTIVITY OF APIS ...

    African Journals Online (AJOL)

    CHEMICAL COMPOSITION AND ANTIOXIDANT ACTIVITY OF APIS. MELLIFERA BEE POLLEN FROM NORTHWEST ALGERIA. A. Rebiai* and T.Lanez. University of El Oued, VTRS Laboratory, P.O. Box 789, 39000, El Oued, Algeria. Received: 08 November 2012 / Accepted: 23 December 2012 / Published online: 31 ...

  11. Standard methods for Apis mellifera propolis research

    Science.gov (United States)

    Propolis is one of the most fascinating honey bee (Apis mellifera L.) products. It is a plant derived product that bees produce from resins that they collect from different plant organs and with which they mix beeswax. Propolis is a building material and a protective agent in the beehive. It also pl...

  12. Integrated platform and API for electrophysiological data.

    Science.gov (United States)

    Sobolev, Andrey; Stoewer, Adrian; Leonhardt, Aljoscha; Rautenberg, Philipp L; Kellner, Christian J; Garbers, Christian; Wachtler, Thomas

    2014-01-01

    Recent advancements in technology and methodology have led to growing amounts of increasingly complex neuroscience data recorded from various species, modalities, and levels of study. The rapid data growth has made efficient data access and flexible, machine-readable data annotation a crucial requisite for neuroscientists. Clear and consistent annotation and organization of data is not only an important ingredient for reproducibility of results and re-use of data, but also essential for collaborative research and data sharing. In particular, efficient data management and interoperability requires a unified approach that integrates data and metadata and provides a common way of accessing this information. In this paper we describe GNData, a data management platform for neurophysiological data. GNData provides a storage system based on a data representation that is suitable to organize data and metadata from any electrophysiological experiment, with a functionality exposed via a common application programming interface (API). Data representation and API structure are compatible with existing approaches for data and metadata representation in neurophysiology. The API implementation is based on the Representational State Transfer (REST) pattern, which enables data access integration in software applications and facilitates the development of tools that communicate with the service. Client libraries that interact with the API provide direct data access from computing environments like Matlab or Python, enabling integration of data management into the scientist's experimental or analysis routines.

  13. Effect of temper and hydrogen embrittlement on mechanical properties of 2,25Cr–1Mo steel grades – Application to Minimum Pressurizing Temperature (MPT) issues. Part II: Vintage reactors and MPT determination

    International Nuclear Information System (INIS)

    Pillot, Sylvain; Chauvy, Cédric; Corre, Stéphanie; Coudreuse, Lionel; Gingell, Andrew; Héritier, Déborah; Toussaint, Patrick

    2013-01-01

    Standard and Vanadium-alloyed 2,25Cr–1Mo steel grades (EN 10028-2 12CrMo9-10/ASTM A387 gr. 22 and 13CrMoV9-10/ASTM A542 tp. D) are commonly used for the fabrication of heavy pressure vessels for applications in petroleum refining plants. These reactors are made of heavy plates, forged shells, forged nozzles and fittings. They are subjected to thermal cycles (stop and go) and to severe service conditions (high temperatures and high hydrogen partial pressures). A primary concern for end-users is the definition of the Minimum Pressurizing Temperature (MPT) of the equipment. This temperature is the lowest temperature at which the vessel can be repressurized after shutdown and insures no risk of brittle failure of the containment body. The MPT is defined by fracture mechanics and/or CVN approaches and calculations. This second part of the paper presents the methodology of MPT determination and the particular case of vintage reactors. MPT determination methodology is explained by using a virtual pressure vessel representative of vessels found in petroleum refineries. A special focus is also set on the evolution of embedded defects

  14. Effect of temper and hydrogen embrittlement on mechanical properties of 2,25Cr–1Mo steel grades – Application to Minimum Pressurizing Temperature (MPT) issues. Part I: General considerations and materials' properties

    International Nuclear Information System (INIS)

    Pillot, Sylvain; Chauvy, Cédric; Corre, Stéphanie; Coudreuse, Lionel; Gingell, Andrew; Héritier, Déborah; Toussaint, Patrick

    2013-01-01

    Standard and Vanadium-alloyed 2,25Cr–1Mo steel grades (EN 10028-2 12CrMo9-10/ASTM A387 gr. 22 and 13CrMoV9-10/ASTM A542 tp. D) are commonly used for the fabrication of heavy pressure vessels for applications in petroleum refining plants. These reactors are made of heavy plates, forged shells, forged nozzles and fittings. They are subjected to thermal cycles (stop and go) and to severe service conditions (high temperatures and high hydrogen partial pressures). A primary concern for end-users is the definition of the Minimum Pressurizing Temperature (MPT) of the equipment. This temperature is the lowest temperature at which the vessel can be repressurized after shutdown and insures no risk of brittle failure of the containment body. The MPT is defined by fracture mechanics and/or CVN approaches and calculations. This first part of the paper presents the impact of thermal aging and exposure to hydrogen on materials' mechanical properties and consequently on the value of MPT

  15. Oxidation behaviour of ferritic stainless steel grade Crofer 22 APU at 700 °C in flowing Ar−75%CO{sub 2}−12%H{sub 2}O

    Energy Technology Data Exchange (ETDEWEB)

    Shariff, Nurul Atikah; Othman, Norinsan Kamil [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Jalar, Azman [Institute of Micro Engineering and Nanoelectronics (IMEN), Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

    2013-11-27

    The oxidation of Ferritic Stainless Steel (FSS) grade Crofer 22 APU has been investigated. FSS alloys were exposed to isothermal conditions in a horizontal tube furnace at a 700 °C in flowing Ar−75%CO{sub 2}−12%H{sub 2}O at a pressure of approximately 1 atm. The results showed that the growth of non protective Fe{sub 2}O{sub 3} and spinel was observed after 50 h exposure in the presence of 12% H{sub 2}O. The weight was increased significantly with time of exposure. The formation of different oxides is presented on the interface of the specimen such as MnCr{sub 2}O{sub 4}, Fe{sub 3}O{sub 4} and Fe{sub 2}O{sub 3} were revealed by X-ray diffraction and supported by EDAX analysis. FSS did not form a protective Cr{sub 2}O{sub 3} layer due to water vapour accelerates the kinetics oxidation. Data of microstructure observation is presented and discussed in this paper in term of water vapour effects.

  16. Kinetics of biofilm formation and desiccation survival of Listeria monocytogenes in single and dual species biofilms with Pseudomonas fluorescens, Serratia proteamaculans or Shewanella baltica on food-grade stainless steel surfaces.

    Science.gov (United States)

    Daneshvar Alavi, Hessam Edin; Truelstrup Hansen, Lisbeth

    2013-01-01

    This study investigated the dynamics of static biofilm formation (100% RH, 15 °C, 48-72 h) and desiccation survival (43% RH, 15 °C, 21 days) of Listeria monocytogenes, in dual species biofilms with the common spoilage bacteria, Pseudomonas fluorescens, Serratia proteamaculans and Shewanella baltica, on the surface of food grade stainless steel. The Gram-negative bacteria reduced the maximum biofilm population of L. monocytogenes in dual species biofilms and increased its inactivation during desiccation. However, due to the higher desiccation resistance of Listeria relative to P. fluorescens and S. baltica, the pathogen survived in greater final numbers. In contrast, S. proteamaculans outcompeted the pathogen during the biofilm formation and exhibited similar desiccation survival, causing the N21 days of Serratia to be ca 3 Log10(CFU cm(-2)) greater than that of Listeria in the dual species biofilm. Microscopy revealed biofilm morphologies with variable amounts of exopolymeric substance and the presence of separate microcolonies. Under these simulated food plant conditions, the fate of L. monocytogenes during formation of mixed biofilms and desiccation depended on the implicit characteristics of the co-cultured bacterium.

  17. HEURISTIC EVALUATION FOR MOBILE APPLICATION (STUDI KASUS: APLIKASI DEPO AUTO 2000 TANJUNG API API PALEMBANG

    Directory of Open Access Journals (Sweden)

    Usman Ependi

    2017-11-01

    Full Text Available Heuristic evaluation merupakan salah satu bentuk usability testing perangkat lunak yang dinilai oleh pengguna (evaluator. Dalam melakukan heuristic evaluation instrumen penilaian terdiri dari sepuluh (10 pernyataan dengan lima pilihan jawaban dalam skala severity ratings. Dalam penelitian ini heuristic evaluation terhadap aplikasi Depo Auto 2000 Tanjung Api-Api Palembang yang dilakukan oleh 4 evaluator.  Hasil dari heuristic evaluation dikelompokkan kedalam  masing-masing instrumen yaitu visibility of system status dengan nilai 0,75, match between system and the real world dengan nilai 0,25, user control and freedom dengan nilai 0,25, consistency and standards dengan nilai 0,75, error prevention dengan nilai 1, recognition rather than recall dengan nilai 1,25, flexibility and efficiency of use dengan nilai 0,25, Aesthetic and minimalist design dengan nilai 0,25, help users recognize, diagnose, and recover from errors dengan nilai 1 dan Help and documentation dengan nilai 0. Dari hasil heuristic evaluation yang dilakukan menunjukkan bahwa evaluator memberikan nilai 0 dan 1 aplikasi Depo Atuo 2000 Tanjung Api-Api Palembang. Hasil penilaian tersebut menunjukkan bahwa aplikasi yang buat tidak ada masalah usability dan hanya memiliki cosmetic problem sehingga aplikasi Depo Auto 2000 Tanjung Api Api Palembang  dapat dinyatakan layak untuk didistribusikan kepada pengguna akhir (end user.

  18. Impact of Nosema ceranae and Nosema apis on individual worker bees of the two host species (Apis cerana and Apis mellifera) and regulation of host immune response.

    Science.gov (United States)

    Sinpoo, Chainarong; Paxton, Robert J; Disayathanoowat, Terd; Krongdang, Sasiprapa; Chantawannakul, Panuwan

    Nosema apis and Nosema ceranae are obligate intracellular microsporidian parasites infecting midgut epithelial cells of host adult honey bees, originally Apis mellifera and Apis cerana respectively. Each microsporidia cross-infects the other host and both microsporidia nowadays have a worldwide distribution. In this study, cross-infection experiments using both N. apis and N. ceranae in both A. mellifera and A. cerana were carried out to compare pathogen proliferation and impact on hosts, including host immune response. Infection by N. ceranae led to higher spore loads than by N. apis in both host species, and there was greater proliferation of microsporidia in A. mellifera compared to A. cerana. Both N. apis and N. ceranae were pathogenic in both host Apis species. N. ceranae induced subtly, though not significantly, higher mortality than N. apis in both host species, yet survival of A. cerana was no different to that of A. mellifera in response to N. apis or N. ceranae. Infections of both host species with N. apis and N. ceranae caused significant up-regulation of AMP genes and cellular mediated immune genes but did not greatly alter apoptosis-related gene expression. In this study, A. cerana enlisted a higher immune response and displayed lower loads of N. apis and N. ceranae spores than A. mellifera, suggesting it may be better able to defend itself against microsporidia infection. We caution against over-interpretation of our results, though, because differences between host and parasite species in survival were insignificant and because size differences between microsporidia species and between host Apis species may alternatively explain the differential proliferation of N. ceranae in A. mellifera. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Improved soil characterization for pipe piles in sand in API RP-2A

    International Nuclear Information System (INIS)

    Hossain, M.K.; Briaud, J.L.

    1993-01-01

    In the offshore, most foundations are steel pipe piles and most of them are designed using the API RP 2A guidelines. For axial capacity of piles in sand the current guidelines in many cases show definite discrepancies when compared against actual load capacities of piles. An updated data base analysis shows that there are three major weaknesses in the current guidelines with respect to soil characterization: (a) the consideration of the lateral earth pressure coefficient, K, as a constant (1.0 or 0.8); (b) the consideration of the unit point bearing resistance, q, as a linear function of depth; and (c) the absence of an unambiguous soil parameter determination process based on reliable in-situ test results. In this paper, specific modifications to the current API RP 2A guidelines are proposed on the basis of a data base analysis to account for the discrepancies arising from (a), (b), and (c) above. These modifications will reduce the discrepancies in the current API RP 2A method and increase the accuracy of the prediction of axial capacity of pipe piles in sand. Furthermore this will make the method fundamentally more consistent with soil behavior in deep foundations

  20. Steel making

    CERN Document Server

    Chakrabarti, A K

    2014-01-01

    "Steel Making" is designed to give students a strong grounding in the theory and state-of-the-art practice of production of steels. This book is primarily focused to meet the needs of undergraduate metallurgical students and candidates for associate membership examinations of professional bodies (AMIIM, AMIE). Besides, for all engineering professionals working in steel plants who need to understand the basic principles of steel making, the text provides a sound introduction to the subject.Beginning with a brief introduction to the historical perspective and current status of steel making together with the reasons for obsolescence of Bessemer converter and open hearth processes, the book moves on to: elaborate the physiochemical principles involved in steel making; explain the operational principles and practices of the modern processes of primary steel making (LD converter, Q-BOP process, and electric furnace process); provide a summary of the developments in secondary refining of steels; discuss principles a...

  1. Population Genetics of Nosema apis and Nosema ceranae: One Host (Apis mellifera) and Two Different Histories

    Science.gov (United States)

    Maside, Xulio; Gómez-Moracho, Tamara; Jara, Laura; Martín-Hernández, Raquel; De la Rúa, Pilar; Higes, Mariano; Bartolomé, Carolina

    2015-01-01

    Two microsporidians are known to infect honey bees: Nosema apis and Nosema ceranae. Whereas population genetics data for the latter have been released in the last few years, such information is still missing for N. apis. Here we analyze the patterns of nucleotide polymorphism at three single-copy loci (PTP2, PTP3 and RPB1) in a collection of Apis mellifera isolates from all over the world, naturally infected either with N. apis (N = 22) or N. ceranae (N = 23), to provide new insights into the genetic diversity, demography and evolution of N. apis, as well as to compare them with evidence from N. ceranae. Neutral variation in N. apis and N. ceranae is of the order of 1%. This amount of diversity suggests that there is no substantial differentiation between the genetic content of the two nuclei present in these parasites, and evidence for genetic recombination provides a putative mechanism for the flow of genetic information between chromosomes. The analysis of the frequency spectrum of neutral variants reveals a significant surplus of low frequency variants, particularly in N. ceranae, and suggests that the populations of the two pathogens are not in mutation-drift equilibrium and that they have experienced a population expansion. Most of the variation in both species occurs within honey bee colonies (between 62%-90% of the total genetic variance), although in N. apis there is evidence for differentiation between parasites isolated from distinct A. mellifera lineages (20%-34% of the total variance), specifically between those collected from lineages A and C (or M). This scenario is consistent with a long-term host-parasite relationship and contrasts with the lack of differentiation observed among host-lineages in N. ceranae (mellifera worldwide population is a recent event. PMID:26720131

  2. Processing hot-dip galvanized AHSS grades: a challenging task

    Energy Technology Data Exchange (ETDEWEB)

    Pichler, A.; Hebesberger, T.; Tragl, E.; Traint, S.; Faderl, J.; Angeli, G.; Koesters, K. [voestalpine Stahl GmbH, Linz (Austria)

    2005-07-01

    High-strength thin sheet steel grades have gained a considerable market share. At present a very strong demand has been observed for DP (dual-phase), CP (complex phase) and TRIP grades, which are often summarized as advanced high-strength steel grades (AHSS). The potential benefits of applying AHSS grades were impressively demonstrated in the ULSAC-AVC project, in which a remarkable reduction in mass and an increase in stiffness and crash safety were achieved by using a very high share of AHSS steel grades. The present contribution concentrates on hot-dip galvanized AHSS thin sheet grades. The hot-dip galvanizeability of such grades is critically discussed after an overview is provided of the metallurgy of AHSS grades, including microstructure, mechanical properties, phase transformations and required alloy design. Based on these fundamentals, the processing of AHSS grades in the hot-dip galvanizing line is discussed and the resulting properties presented. (orig.)

  3. Search without Boundaries Using Simple APIs

    Science.gov (United States)

    Tong, Qi

    2009-01-01

    The U.S. Geological Survey (USGS) Library, where the author serves as the digital services librarian, is increasingly challenged to make it easier for users to find information from many heterogeneous information sources. Information is scattered throughout different software applications (i.e., library catalog, federated search engine, link resolver, and vendor websites), and each specializes in one thing. How could the library integrate the functionalities of one application with another and provide a single point of entry for users to search across? To improve the user experience, the library launched an effort to integrate the federated search engine into the library's intranet website. The result is a simple search box that leverages the federated search engine's built-in application programming interfaces (APIs). In this article, the author describes how this project demonstrated the power of APIs and their potential to be used by other enterprise search portals inside or outside of the library.

  4. Yoink: An interaction-based partitioning API.

    Science.gov (United States)

    Zheng, Min; Waller, Mark P

    2018-05-15

    Herein, we describe the implementation details of our interaction-based partitioning API (application programming interface) called Yoink for QM/MM modeling and fragment-based quantum chemistry studies. Interactions are detected by computing density descriptors such as reduced density gradient, density overlap regions indicator, and single exponential decay detector. Only molecules having an interaction with a user-definable QM core are added to the QM region of a hybrid QM/MM calculation. Moreover, a set of molecule pairs having density-based interactions within a molecular system can be computed in Yoink, and an interaction graph can then be constructed. Standard graph clustering methods can then be applied to construct fragments for further quantum chemical calculations. The Yoink API is licensed under Apache 2.0 and can be accessed via yoink.wallerlab.org. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

  5. Effects of Nosema apis, N. ceranae, and coinfections on honey bee (Apis mellifera) learning and memory.

    Science.gov (United States)

    Charbonneau, Lise R; Hillier, Neil Kirk; Rogers, Richard E L; Williams, Geoffrey R; Shutler, Dave

    2016-03-10

    Western honey bees (Apis mellifera) face an increasing number of challenges that in recent years have led to significant economic effects on apiculture, with attendant consequences for agriculture. Nosemosis is a fungal infection of honey bees caused by either Nosema apis or N. ceranae. The putative greater virulence of N. ceranae has spurred interest in understanding how it differs from N. apis. Little is known of effects of N. apis or N. ceranae on honey bee learning and memory. Following a Pavlovian model that relies on the proboscis extension reflex, we compared acquisition learning and long-term memory recall of uninfected (control) honey bees versus those inoculated with N. apis, N. ceranae, or both. We also tested whether spore intensity was associated with variation in learning and memory. Neither learning nor memory differed among treatments. There was no evidence of a relationship between spore intensity and learning, and only limited evidence of a negative effect on memory; this occurred only in the co-inoculation treatment. Our results suggest that if Nosema spp. are contributing to unusually high colony losses in recent years, the mechanism by which they may affect honey bees is probably not related to effects on learning or memory, at least as assessed by the proboscis extension reflex.

  6. Hybrid origins of Australian honeybees (Apis mellifera)

    OpenAIRE

    Chapman , Nadine C.; Harpur , Brock A.; Lim , Julianne; Rinderer , Thomas E.; Allsopp , Michael H.; Zayed , Amro; Oldroyd , Benjamin P.

    2016-01-01

    International audience; Abstract With increased globalisation and homogenisation, the maintenance of genetic integrity in local populations of agriculturally important species is of increasing concern. The western honeybee (Apis mellifera) provides an interesting perspective as it is both managed and wild, with a large native range and much larger introduced range. We employed a newly created 95 single nucleotide polymorphism (SNP) test to characterise the genetic ancestry of the Australian c...

  7. Fragmentation of armor piercing steel projectiles upon oblique perforation of steel plates

    Directory of Open Access Journals (Sweden)

    Aizik F.

    2012-08-01

    Full Text Available In this study, a constitutive strength and failure model for a steel core of a14.5 mm API projectile was developed. Dynamic response of a projectile steel core was described by the Johnson-Cook constitutive model combined with principal tensile stress spall model. In order to obtain the parameters required for numerical description of projectile core material behavior, a series of planar impact experiments was done. The parameters of the Johnson-Cook constitutive model were extracted by matching simulated and experimental velocity profiles of planar impact. A series of oblique ballistic experiments with x-ray monitoring was carried out to study the effect of obliquity angle and armor steel plate thickness on shattering behavior of the 14.5 mm API projectile. According to analysis of x-ray images the fragmentation level increases with both steel plate thickness and angle of inclination. The numerical modeling of the ballistic experiments was done using commercial finite element code, LS-DYNA. Dynamic response of high hardness (HH armor steel was described using a modified Johnson-Cook strength and failure model. A series of simulations with various values of maximal principal tensile stress was run in order to capture the overall fracture behavior of the projectile’s core. Reasonable agreement between simulated and x-ray failure pattern of projectile core has been observed.

  8. Influence of preheating on API 5L-X80 pipeline joint welding with self shielded flux-cored wire; Influencia del precalentamiento en las propiedades de uniones soldadas de acero API 5L-X80 soldadas con alambre tubular autoprotegido

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, R.; Silva, J. H. F.; Trevisan, R. E.

    2004-07-01

    The present work refers to the characterization of API 5L-X80 pipeline joints welded with self-shielded flux cored wire. This process was evaluated under preheating conditions, with an uniform and steady heat input. All joints were welded in flat position (1G), with the pipe turning and the torch still. Tube dimensions were 762 mm in external diameter and 16 mm in thickness. Welds were applied on single V-groove, with six weld beads, along with three levels of preheating temperatures (room temperature, 100 degree centigree, 160 degree centigree). These temperatures were maintained as inter pass temperature. The filler metal E71T8-K6 with mechanical properties different from parent metal was used in under matched conditions. The weld characterization is presented according to the mechanical test results of tensile strength, hardness and impact test. The mechanical tests were conducted according to API 1104, AWS and ASTM standards. API 1104 and API 51 were used as screening criteria. According to the results obtained, it was possible to remark that it is appropriate to weld API 5L-X80 steel ducts with Self-shielded Flux Cored wires, in conformance to the API standards and no preheat temperature is necessary. (Author) 22 refs.

  9. Grading of mitral regurgitation in mitral valve prolapse using the average pixel intensity method.

    Science.gov (United States)

    Kamoen, Victor; El Haddad, Milad; De Buyzere, Marc; De Backer, Tine; Timmermans, Frank

    2018-05-01

    We recently reported the feasibility of the average pixel intensity (API) method for grading mitral regurgitation (MR) in a heterogeneous MR population. Since mitral valve prolapse (MVP) is an important cause of primary MR, we more specifically investigated the feasibility of the API method and the MR flow dynamics in patients with MVP. Transthoracic echocardiography was performed by a single operator in consecutive MVP patients (n=112). MR was assessed using the API method, color Doppler, vena contracta width (VCW), effective regurgitant orifice area (PISA-EROA) and regurgitant volume (PISA-RV). The API method was feasible in 89% of all MVP patients (68%, 71% for VCW and PISA method, respectively ;pMVP with non-holosystolic MR were 0.989 and 0.995. For the overall MVP-MR population, API had significant correlations with direct and indirect measures of MR severity. Based on ROC curves, an API cutoff value of 125 au was suggested to identify severe MR in MVP and a MR duration/systolic time ratioMVP-MR) identifies patients with non-severe MR (APIMVP had severe MR (API>125). Finally, API analysis of the proto-, mid- and telesystolic phases of MR in MVP showed different kinetics in non-holosystolic compared to holosystolic MVP. The API method is a feasible and reproducible method for grading MVP-MR. As the API method takes into account the temporal MR flow changes during the entire systolic cycle, it may be of added value in clinical practice. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. BEE VENOM TRAP DESIGN OF APIS MELLIFERA L. AND APIS CERANA F. HONEY BEES

    OpenAIRE

    Budiaman

    2015-01-01

    The nectar and pollen of flowers which are abundance have not been taken into account for any purpose in forest, agriculture and plantation area. Honey bees such as Apis mellifera L. and Apis cerana F. had known as biological pollinators which could converted the flower components to be high economy products in the forms of honey, royal jelly, propolis, bee wax and bee venom. Among the products, bee venom has the best selling value, but the method of it???s optimal production has not been ext...

  11. Experimental and numerical simulation of carbon manganese steel ...

    African Journals Online (AJOL)

    Experimental and numerical simulation of carbon manganese steel for cyclic plastic behaviour. J Shit, S Dhar, S Acharyya. Abstract. The paper deals with finite element modeling of saturated low cycle fatigue and the cyclic hardening phenomena of the materials Sa333 grade 6 carbon steel and SS316 stainless steel.

  12. Notch aspects of RSP steel microstructure

    Directory of Open Access Journals (Sweden)

    Michal Černý

    2012-01-01

    Full Text Available For a rather long time, basic research projects have been focused on examinations of mechanical properties for Rapid Solidification Powder (RSP steels. These state-of-art steels are commonly known as “powdered steels“. In fact, they combine distinctive attributes of conventional steel alloys with unusual resistance of construction material manufactured by so called “pseudo-powdered” metallurgy.Choice of suitable materials for experimental verification was carried out based on characteristic application of so called “modern steel”. First, groups of stainless and tool steel types (steel grades ČSN 17 and 19 were selected. These provided representative specimens for the actual comparison experiment. For stainless steel type, two steel types were chosen: hardenable X47Cr14 (ČSN 17 029 stainless steel and non-hardenable X2CrNiMo18-14-3 (ČSN 17 350 steel. They are suitable e.g. for surgical tools and replacements (respectively. For tooling materials, C80U (ČSN 19 152 carbon steel and American D2 highly-alloyed steel (ČSN “equivalent” being 19 572 steel were chosen for the project. Finally, the M390 Böhler steel was chosen as representative of powdered (atomized steels. The goal of this paper is to discuss structural aspects of modern stainless and tool steel types and to compare them against the steel made by the RSP method. Based on the paper's results, impact of powdered steel structural characteristics on the resistance to crack initiation shall be evaluated.

  13. X-ray diffraction study of microstructural changes during fatigue damage initiation in pipe steels: Role of the initial dislocation structure

    Energy Technology Data Exchange (ETDEWEB)

    Pinheiro, B., E-mail: bianca@lts.coppe.ufrj.br [Laboratory of Mechanics of Lille (LML), UMR CNRS 8107, University Lille 1, Boulevard Paul Langevin, Cité Scientifique, 59655 Villeneuve d' Ascq (France); Lesage, J. [Laboratory of Mechanics of Lille (LML), UMR CNRS 8107, University Lille 1, Boulevard Paul Langevin, Cité Scientifique, 59655 Villeneuve d' Ascq (France); Pasqualino, I. [Subsea Technology Laboratory (LTS), Ocean Engineering Department, COPPE/Federal University of Rio de Janeiro, PO Box 68508, Cidade Universitária, CEP 21945-970, Rio de Janeiro/RJ (Brazil); Bemporad, E. [University of Rome “ROMA TRE”, Mechanical and Industrial Eng. Dept., Via Vasca Navale 79, 00146 Rome (Italy); Benseddiq, N. [Laboratory of Mechanics of Lille (LML), UMR CNRS 8107, University Lille 1, Boulevard Paul Langevin, Cité Scientifique, 59655 Villeneuve d' Ascq (France)

    2013-09-15

    The present work is the second part of an ongoing study of microstructural changes during fatigue damage initiation in pipe steels [B. Pinheiro et al., Mat. Sci. Eng., A 532 (2012) 158–166]. Microdeformations and residual stresses (macrostresses) are evaluated by X-ray diffraction during alternating bending fatigue tests on samples taken from an API 5L X60 grade steel pipe. Microdeformations are evaluated from the full width at half maximum (FWHM) of the diffraction peak and residual stresses are estimated from the peak shift. Here, to understand the role of the initial dislocation structure, annealed samples are considered. As previously found for as-machined samples, the evolution of microdeformations shows three regular successive stages, but now with an increase during the first stage. The amplitude of each stage is accentuated with increasing stress amplitude, while its duration is reduced. Residual stresses show a similar trend, with stages of the same durations than those observed for FWHM, respectively. Additionally, changes in density and distribution of dislocations are observed by transmission electron microscopy combined with the technique of focused ion beam. The results are very encouraging for the development of a future indicator of fatigue damage initiation for pipe steels based on microstructural changes measured by X-ray diffraction.

  14. X-ray diffraction study of microstructural changes during fatigue damage initiation in pipe steels: Role of the initial dislocation structure

    International Nuclear Information System (INIS)

    Pinheiro, B.; Lesage, J.; Pasqualino, I.; Bemporad, E.; Benseddiq, N.

    2013-01-01

    The present work is the second part of an ongoing study of microstructural changes during fatigue damage initiation in pipe steels [B. Pinheiro et al., Mat. Sci. Eng., A 532 (2012) 158–166]. Microdeformations and residual stresses (macrostresses) are evaluated by X-ray diffraction during alternating bending fatigue tests on samples taken from an API 5L X60 grade steel pipe. Microdeformations are evaluated from the full width at half maximum (FWHM) of the diffraction peak and residual stresses are estimated from the peak shift. Here, to understand the role of the initial dislocation structure, annealed samples are considered. As previously found for as-machined samples, the evolution of microdeformations shows three regular successive stages, but now with an increase during the first stage. The amplitude of each stage is accentuated with increasing stress amplitude, while its duration is reduced. Residual stresses show a similar trend, with stages of the same durations than those observed for FWHM, respectively. Additionally, changes in density and distribution of dislocations are observed by transmission electron microscopy combined with the technique of focused ion beam. The results are very encouraging for the development of a future indicator of fatigue damage initiation for pipe steels based on microstructural changes measured by X-ray diffraction

  15. Updated API document 6A will close API-ISO 9000 gap. [Oil and gas wellhead standards

    Energy Technology Data Exchange (ETDEWEB)

    Bell, S.

    1993-10-01

    The 17th edition of the American Petroleum Institute's (API) document 6A, covering wellheads and their components, is due early next year. As the API vs. International Standards Organization (ISO) 9000 struggle continues, this edition of 6A eliminates some unnecessary specifications, clarifies others, and includes metric specifications accepted by the ISO. The 17th edition will clarify some of the interpretations from earlier editions and further advise users how to acquire the API monogram. The goal of this edition is to make 6A acceptable to ISO as an international document so API can maintain control over petroleum equipment specifications and provide input and guidance in future regulations.

  16. Beebread from Apis mellifera and Apis dorsata. Comparative Chemical Composition and Bioactivity

    Directory of Open Access Journals (Sweden)

    Otilia BOBIS

    2017-05-01

    Full Text Available Beebread is a valuable bee product, both for bee nutrition and for humans. The high nutritional and bioactive properties of beebread were evaluated by chemical composition analysis of beebread from Apis mellifera and Apis dorsata. Bee bread harvested from Romania and India, coming from Apis mellifera and Apis dorsata bees, were evaluated for their chemical composition. Analyses were made in APHIS Laboratory from USAMV Cluj, using validated methods for bee products. Lipids were determined by the Soxhlet extraction method, total protein content was determined by Kjehldahl method, sugar spectrum was determined by high performance liquid chromatography with refractive index detection (HPLC-IR. Water content of beebread samples were situated between 11.45 and 16.46%, total protein content between 16.84 and 19.19% and total lipids between 6.36 and 13.47%.  Beebread has high bioactive properties which can be expressed as antioxidant and/or antibacterial activity. Chemical composition and bioactive properties of beebread is influenced by floral origin of the pollen which the bees collect and place in combs for fermentation. Also the climatic conditions have an important role in developing different fermentation compounds, that may act as antioxidants or antibacterial agents.

  17. Rare royal families in honeybees, Apis mellifera

    Science.gov (United States)

    Moritz, Robin F. A.; Lattorff, H. Michael G.; Neumann, Peter; Kraus, F. Bernhard; Radloff, Sarah E.; Hepburn, H. Randall

    2005-10-01

    The queen is the dominant female in the honeybee colony, Apis mellifera, and controls reproduction. Queen larvae are selected by the workers and are fed a special diet (royal jelly), which determines caste. Because queens mate with many males a large number of subfamilies coexist in the colony. As a consequence, there is a considerable potential for conflict among the subfamilies over queen rearing. Here we show that honeybee queens are not reared at random but are preferentially reared from rare “royal” subfamilies, which have extremely low frequencies in the colony's worker force but a high frequency in the queens reared.

  18. Adaptive runtime for a multiprocessing API

    Science.gov (United States)

    Antao, Samuel F.; Bertolli, Carlo; Eichenberger, Alexandre E.; O'Brien, John K.

    2016-11-15

    A computer-implemented method includes selecting a runtime for executing a program. The runtime includes a first combination of feature implementations, where each feature implementation implements a feature of an application programming interface (API). Execution of the program is monitored, and the execution uses the runtime. Monitor data is generated based on the monitoring. A second combination of feature implementations are selected, by a computer processor, where the selection is based at least in part on the monitor data. The runtime is modified by activating the second combination of feature implementations to replace the first combination of feature implementations.

  19. API 5L X80 PSL2 pipes manufactured by ERW process: TenarisConfab and USIMINAS development; Tubos API 5L X80 PSL2 processados por ERW: desenvolvimento TenarisConfab-Usiminas

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Ronaldo C.; Roza, Juliana E.; Kojima, Sergio S. [TenarisConfab, Pindamonhangaba, SP (Brazil); Miranda, Lucio S.; Turani, Leonardo O. [USIMINAS, Ipatinga, MG (Brazil)

    2005-07-01

    The utilization of high strength steels can decrease, both, installation and operation costs of a new pipeline, since the increase of mechanical resistance can reduce the pipe wall thickness and, consequently, the weight of the pipe. For this purpose, the manufacture of electric resistance welding (ERW) pipes is recent, and it comes as an opportunity for gas pipelines, mainly onshore projects. As a function of their larger productivity, ERW pipes are more economically attractive than those produced by seamless and SAW processes. TenarisConfab and USIMINAS, through studies and investments in manufacturing processes, have been working to increase their skills, in order to supply ERW pipes in API 5L X80 PSL2 steel. The steel elaborated by USIMINAS is low C, high Mn, Nb, V and Ti microalloyed, and with additions of Cr and Mo, aiming to produce hot rolled coils with acicular microstructure, achieved as a combination between its chemical composition and higher cooling rates after hot rolling. The results in {phi}18''(457 mm) x 0,469''(11,91 mm) pipes are presented in this article. High toughness values reached at very low temperatures suggest that ERW API 5L X80 PSL2 pipes developed by TenarisConfab and USIMINAS may be an excellent option of choice for onshore projects that request pipes in diameters up to 20''(508 mm) and thickness up to 0,500'' (12,7 mm). (author)

  20. Stainless Steel Leaches Nickel and Chromium into Foods During Cooking

    OpenAIRE

    Kamerud, Kristin L.; Hobbie, Kevin A.; Anderson, Kim A.

    2013-01-01

    Toxicological studies show that oral doses of nickel and chromium can cause cutaneous adverse reactions such as dermatitis. Additional dietary sources, such as leaching from stainless steel cookware during food preparation, are not well characterized. This study examined stainless steel grades, cooking time, repetitive cooking cycles, and multiple types of tomato sauces for their effects on nickel and chromium leaching. Trials included three types of stainless steels and a stainless steel sau...

  1. Advanced high strength steels for automotive industry

    Energy Technology Data Exchange (ETDEWEB)

    Galan, J.; Samek, L.; Verleysen, P.; Verbeken, K.; Houbert, Y.

    2012-11-01

    The car industry is facing pressure because of the growing demand for more fuel-efficient passenger cars. In order to limit energy consumption and air pollution the weight of the car body has to be reduced. At the same time, high levels of safety have to be guaranteed. In this situation, the choice of material becomes a key decision in car design. As a response to the requirements of the automotive sector, high strength steels and advanced high strength steels have been developed by the steel industry. These modern steel grades offer an excellent balance of low cost, light weight and mechanical properties. (Author) 48 refs.

  2. Welding Metallurgy and Weldability of Stainless Steels

    Science.gov (United States)

    Lippold, John C.; Kotecki, Damian J.

    2005-03-01

    Welding Metallurgy and Weldability of Stainless Steels, the first book in over twenty years to address welding metallurgy and weldability issues associated with stainless steel, offers the most up-to-date and comprehensive treatment of these topics currently available. The authors emphasize fundamental metallurgical principles governing microstructure evolution and property development of stainless steels, including martensistic, ferric, austenitic, duplex, and precipitation hardening grades. They present a logical and well-organized look at the history, evolution, and primary uses of each stainless steel, including detailed descriptions of the associated weldability issues.

  3. grlc Makes GitHub Taste Like Linked Data APIs

    NARCIS (Netherlands)

    Meroño-Peñuela, A.; Hoekstra, Rinke; Sack, H; Rizzo, G; Steinmetz, N; Mladenić, D; Auer, S; Lange, C

    2016-01-01

    Building Web APIs on top of SPARQL endpoints is becoming a common practice to enable universal access to the integration favorable dataspace of Linked Data. However, the Linked Data community cannot expect users to learn SPARQL to query this dataspace, and Web APIs are the most extended way of

  4. grlc Makes GitHub Taste Like Linked Data APIs

    NARCIS (Netherlands)

    Merono Penuela, A.; Hoekstra, R.J.

    2016-01-01

    Building Web APIs on top of SPARQL endpoints is becoming common practice. It enables universal access to the integration favorable data space of Linked Data. In the majority of use cases, users cannot be expected to learn SPARQL to query this data space. Web APIs are the most common way to enable

  5. grlc Makes GitHub Taste Like Linked Data APIs

    NARCIS (Netherlands)

    Meroño-Peñuela, A.; Hoekstra, R.

    2016-01-01

    Building Web APIs on top of SPARQL endpoints is becoming a common practice to enable universal access to the integration favorable dataspace of Linked Data. However, the Linked Data community cannot expect users to learn SPARQL to query this dataspace, and Web APIs are the most common way of

  6. Experience API: Flexible, Decentralized and Activity-Centric Data Collection

    Science.gov (United States)

    Kevan, Jonathan M.; Ryan, Paul R.

    2016-01-01

    This emerging technology report describes the Experience API (xAPI), a new e-learning specification designed to support the learning community in standardizing and collecting both formal and informal distributed learning activities. Informed by Activity Theory, a framework aligned with constructivism, data is collected in the form of activity…

  7. A Web API ecosystem through feature-based reuse

    NARCIS (Netherlands)

    Verborgh, Ruben; Dumontier, Michel

    2016-01-01

    The current Web API landscape does not scale well: every API requires its own hardcoded clients in an unusually short-lived, tightly coupled relationship of highly subjective quality. This directly leads to inflated development costs, and prevents the design of a more intelligent generation of

  8. Hymenoptera venom review focusing on Apis mellifera

    Directory of Open Access Journals (Sweden)

    P. R. de Lima

    2003-01-01

    Full Text Available Hymenoptera venoms are complex mixtures containing simple organic molecules, proteins, peptides, and other bioactive elements. Several of these components have been isolated and characterized, and their primary structures determined by biochemical techniques. These compounds are responsible for many toxic or allergic reactions in different organisms, such as local pain, inflammation, itching, irritation, and moderate or severe allergic reactions. The most extensively characterized Hymenoptera venoms are bee venoms, mainly from the Apis genus and also from social wasps and ant species. However, there is little information about other Hymenoptera groups. The Apis venom presents high molecular weight molecules - enzymes with a molecular weight higher than 10.0 kDa - and peptides. The best studied enzymes are phospholipase A2, responsible for cleaving the membrane phospholipids, hyaluronidase, which degrades the matrix component hyaluronic acid into non-viscous segments and acid phosphatase acting on organic phosphates. The main peptide compounds of bee venom are lytic peptide melittin, apamin (neurotoxic, and mastocyte degranulating peptide (MCD.

  9. Investigating an API for resilient exascale computing.

    Energy Technology Data Exchange (ETDEWEB)

    Stearley, Jon R.; Tomkins, James; VanDyke, John P.; Ferreira, Kurt Brian; Laros, James H.,; Bridges, Patrick

    2013-05-01

    Increased HPC capability comes with increased complexity, part counts, and fault occurrences. In- creasing the resilience of systems and applications to faults is a critical requirement facing the viability of exascale systems, as the overhead of traditional checkpoint/restart is projected to outweigh its bene ts due to fault rates outpacing I/O bandwidths. As faults occur and propagate throughout hardware and software layers, pervasive noti cation and handling mechanisms are necessary. This report describes an initial investigation of fault types and programming interfaces to mitigate them. Proof-of-concept APIs are presented for the frequent and important cases of memory errors and node failures, and a strategy proposed for lesystem failures. These involve changes to the operating system, runtime, I/O library, and application layers. While a single API for fault handling among hardware and OS and application system-wide remains elusive, the e ort increased our understanding of both the mountainous challenges and the promising trailheads. 3

  10. The geospatial data quality REST API for primary biodiversity data.

    Science.gov (United States)

    Otegui, Javier; Guralnick, Robert P

    2016-06-01

    We present a REST web service to assess the geospatial quality of primary biodiversity data. It enables access to basic and advanced functions to detect completeness and consistency issues as well as general errors in the provided record or set of records. The API uses JSON for data interchange and efficient parallelization techniques for fast assessments of large datasets. The Geospatial Data Quality API is part of the VertNet set of APIs. It can be accessed at http://api-geospatial.vertnet-portal.appspot.com/geospatial and is already implemented in the VertNet data portal for quality reporting. Source code is freely available under GPL license from http://www.github.com/vertnet/api-geospatial javier.otegui@gmail.com or rguralnick@flmnh.ufl.edu Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press.

  11. Inhibition of Corrosion of Carbon Steel in 3.5% NaCl Solution by Myrmecodia Pendans Extract

    Directory of Open Access Journals (Sweden)

    Atria Pradityana

    2016-01-01

    Full Text Available Inhibitor is a substance that is added to the corrosive media to inhibit corrosion rate. Organic inhibitors are preferred to inorganic ones since they are environmentally friendly. One of the organic compounds which is rarely reported as a corrosion inhibitor is Myrmecodia Pendans. The organic compounds can be adsorbed on the metal surface and block the active surface to reduce the rate of corrosion. In this study, the used pipe was carbon steel API 5L Grade B with 3.5% NaCl solution as the corrosion medium. The objective of this research was to analyze the inhibition mechanism Myrmecodia Pendans towards carbon steel in a corrosion medium. Concentration variations of extract Myrmecodia Pendans were 0–500 ppm. Fourier Transform Infrared (FTIR was used for chemical characterization of Myrmecodia Pendans. Polarization and Electrochemical Impedance Spectroscopy (EIS were used to measure the corrosion rate and behaviour. From the electrochemical measurements, it was found that the addition of 400 mg/L inhibitor gave the highest inhibition efficiency. Myrmecodia Pendans acted as a corrosion inhibitor by forming a thin layer on the metal surface.

  12. Coming 5th Edition of the API Standard 618: major changes compared to the API 618, 4th edition

    NARCIS (Netherlands)

    Pyle, A.; Eijk, A.; Elferink, H.

    2003-01-01

    This paper will present the highlights of changes that will be found in the 5th Edition of API 618, which is expected to be published in late 2003 or early 2004. Approximately every 5 years the API Standards are revised in such a way that the latest field experiences and proven designs are included

  13. fine-GRAPE : Fine-grained APi usage extractor – an approach and dataset to investigate API usage

    NARCIS (Netherlands)

    Sawant, A.A.; Bacchelli, A.

    An Application Programming Interface (API) provides a set of functionalities to a developer with the aim of enabling reuse. APIs have been investigated from different angles such as popularity usage and evolution to get a better understanding of their various characteristics. For such studies,

  14. EKSPLORASI AKTINOMISET SEBAGAI PENGHASIL ANTIBIOTIKA DARI TANAH MANGROVE Sonneratia caseolaris DI TANJUNG API API

    Directory of Open Access Journals (Sweden)

    Awalul Fatiqin

    2015-08-01

    Full Text Available Actinomycetes are soil organisms that have traits that are common to bacteria and fungi but also have quite different characteristics that limit into one group which is distinctly different. Study aimed to explore the mangrove actinomycetes from soil and tested the antibacterial potency. Soil samples taken from the mangrove land at Tanjung Api-api mangrove species Sonneratia caseolaris. Activity test antibacterial using a method modified disk a test bacterium Escherichia coli. Identification isolates of actinomycetes by observing the character of macroscopic colonies, microscopic conidia. The results showed that the obtained three different actinomycetes isolates, 1 isolate has the most potential ability to inhibit bacterial growth test with an average value of 1:13 cm in inhibiting the bacteria Escherichia coli.

  15. INHIBITION EFFECT OF FLAVONOID EXTRACT OF Euphorbia Guyoniana ON THE CORROSION OF MILD STEEL IN H2SO4 MEDIUM

    Directory of Open Access Journals (Sweden)

    S. Chihi

    2009-08-01

    Full Text Available The influence of flavonoids extracts of three parts of Euphorbia Guyoniana towards the corrosion of type API 5L X52 steel in 15% H2SO4 has been evaluated by weight loss method and polarization technique. The results showed that extracts are a good inhibitors for API 5L X52 steel in this medium. The corrosion inhibition efficiency increases on increasing plant extracts concentration. The inhibition is attributed to the adsorption of the surface of the metal. Potentiodynamic polarization results revealed that the studied inhibitors behave as a mixed type.

  16. Analysing PKCS#11 Key Management APIs with Unbounded Fresh Data

    Science.gov (United States)

    Fröschle, Sibylle; Steel, Graham

    We extend Delaune, Kremer and Steel’s framework for analysis of PKCS#11-based APIs from bounded to unbounded fresh data. We achieve this by: formally defining the notion of an attribute policy; showing that a well-designed API should have a certain class of policy we call complete; showing that APIs with complete policies may be safely abstracted to APIs where the attributes are fixed; and proving that these static APIs can be analysed in a small bounded model such that security properties will hold for the unbounded case. We automate analysis in our framework using the SAT-based security protocol model checker SATMC. We show that a symmetric key management subset of the Eracom PKCS#11 API, used in their ProtectServer product, preserves the secrecy of sensitive keys for unbounded numbers of fresh keys and handles, i.e. pointers to keys. We also show that this API is not robust: if an encryption key is lost to the intruder, SATMC finds an attack whereby all the keys may be compromised.

  17. Compositional mining of multiple object API protocols through state abstraction.

    Science.gov (United States)

    Dai, Ziying; Mao, Xiaoguang; Lei, Yan; Qi, Yuhua; Wang, Rui; Gu, Bin

    2013-01-01

    API protocols specify correct sequences of method invocations. Despite their usefulness, API protocols are often unavailable in practice because writing them is cumbersome and error prone. Multiple object API protocols are more expressive than single object API protocols. However, the huge number of objects of typical object-oriented programs poses a major challenge to the automatic mining of multiple object API protocols: besides maintaining scalability, it is important to capture various object interactions. Current approaches utilize various heuristics to focus on small sets of methods. In this paper, we present a general, scalable, multiple object API protocols mining approach that can capture all object interactions. Our approach uses abstract field values to label object states during the mining process. We first mine single object typestates as finite state automata whose transitions are annotated with states of interacting objects before and after the execution of the corresponding method and then construct multiple object API protocols by composing these annotated single object typestates. We implement our approach for Java and evaluate it through a series of experiments.

  18. Effect of Microstructure on the Wear Behavior of Heat Treated SS-304 Stainless Steel

    OpenAIRE

    S. Kumar

    2016-01-01

    Sliding wear characteristics of some heat treated SS-304 stainless steel against EN-8 steel in dry condition have been studied in the present experimental work. Samples of SS-304 stainless steel have been heated in a muffle furnace in desired temperature and allowed to dwell for two hours. The heated specimen are then cooled in different media namely inside the furnace, open air, cutting grade oil (grade 44) and water at room temperature to obtain different grades of heat treatment. Microstr...

  19. Aggressiveness index of Apis Mellifera (Hymenoptera: Aapidae

    Directory of Open Access Journals (Sweden)

    Jennyfer Insuasty Torres

    2004-01-01

    Full Text Available An index measuring the aggressiveness among ten colonies of Apis mellifera was elaborated based on the third generation synthetic indices by Charum et al. (1999. The index values are subject to a fixed parameter used as the beginning or standard value, and correspond to the aggressive features of some Africans colonies studied by Rothenbuler et al. (1968. In the ten colonies the index values are notably smaller than those of African colonies and are biased to the lowest values. This indicates, that neither of the colonies presents an extreme aggressive behavior and it is possible that they have not Africans genotypes. These results are an indirect proof of the index. Nevertheless, it could be improved by the introduction of other factors such as, climate and colony management.

  20. The IRMIS object model and services API

    International Nuclear Information System (INIS)

    Saunders, C.; Dohan, D.A.; Arnold, N.D.

    2005-01-01

    The relational model developed for the Integrated Relational Model of Installed Systems (IRMIS) toolkit has been successfully used to capture the Advanced Photon Source (APS) control system software (EPICS process variables and their definitions). The relational tables are populated by a crawler script that parses each Input/Output Controller (IOC) start-up file when an IOC reboot is detected. User interaction is provided by a Java Swing application that acts as a desktop for viewing the process variable information. Mapping between the display objects and the relational tables was carried out with the Hibernate Object Relational Modeling (ORM) framework. Work is well underway at the APS to extend the relational modeling to include control system hardware. For this work, due in part to the complex user interaction required, the primary application development environment has shifted from the relational database view to the object oriented (Java) perspective. With this approach, the business logic is executed in Java rather than in SQL stored procedures. This paper describes the object model used to represent control system software, hardware, and interconnects in IRMIS. We also describe the services API used to encapsulate the required behaviors for creating and maintaining the complex data. In addition to the core schema and object model, many important concepts in IRMIS are captured by the services API. IRMIS is an ambitious collaborative effort for defining and developing a relational database and associated applications to comprehensively document the large and complex EPICS-based control systems of today's accelerators. The documentation effort includes process variables, control system hardware, and interconnections. The approach could also be used to document all components of the accelerator, including mechanical, vacuum, power supplies, etc. One key aspect of IRMIS is that it is a documentation framework, not a design and development tool. We do not

  1. Supply chain of steel industries for the nuclear power plant construction in Indonesia

    International Nuclear Information System (INIS)

    Dharu Dewi; Sahala M Lumbanraja

    2017-01-01

    Nuclear Power Plant (NPP) Construction needs steel materials for the manufacturing of heavy components and civil work construction. National industries is expected to supply steel components especially for non nuclear component needs. Supply chain of steel industries is required to know the potency of steel industries from upstream to downstream industries which can support the NPP construction sustainability. The type of steel needed in the NPP construction consist of structure steel, rebar, steel plate, etc. The aim of the study is to identify supply chain of steel industries from upstream industries to downstream industries so that they can supply steel needs in the NPP construction. The methodology used are literature review and industries survey by purposive sampling test which sent questionnaires and carrying out technical visits to the potential industries to supply steel components for NPP construction. From the analysis of the questionnaires and survey, it has been obtained that the Indonesian steel industries capable of supplying steel for construction materials of non-nuclear parts are PT. Krakatau Steel, PT. Gunung Steel Group (PT Gunung Garuda and PT. Gunung Raja Paksi), PT. Cilegon Fabricators and PT. Ometraco Arya Samanta. While steel materials for primary components with nuclear grade, such as steel materials for reactor vessels and pressure vessels, the Indonesian steel industry has not been able to supply them. Therefore, the Indonesian steel industries must improve its capability, both in raw material processing and fabrication capability in order to meet the requirements of specifications, codes and standards of nuclear grade. (author)

  2. Tool steels

    DEFF Research Database (Denmark)

    Højerslev, C.

    2001-01-01

    On designing a tool steel, its composition and heat treatment parameters are chosen to provide a hardened and tempered martensitic matrix in which carbides are evenly distributed. In this condition the matrix has an optimum combination of hardness andtoughness, the primary carbides provide...... resistance against abrasive wear and secondary carbides (if any) increase the resistance against plastic deformation. Tool steels are alloyed with carbide forming elements (Typically: vanadium, tungsten, molybdenumand chromium) furthermore some steel types contains cobalt. Addition of alloying elements...... serves primarily two purpose (i) to improve the hardenabillity and (ii) to provide harder and thermally more stable carbides than cementite. Assuming proper heattreatment, the properties of a tool steel depends on the which alloying elements are added and their respective concentrations....

  3. Building Hypermedia APIs with HTML5 and Node

    CERN Document Server

    Amundsen, Mike

    2011-01-01

    With this concise book, you'll learn the art of building hypermedia APIs that don't simply run on the Web, but that actually exist in the Web. You'll start with the general principles and technologies behind this architectural approach, and then dive hands-on into three fully-functional API examples. Too many APIs rely on concepts rooted in desktop and local area network patterns that don't scale well-costly solutions that are difficult to maintain over time. This book shows system architects and web developers how to design and implement human- and machine-readable web services that remain

  4. Privacy Issues of the W3C Geolocation API

    OpenAIRE

    Doty, Nick; Mulligan, Deirdre K.; Wilde, Erik

    2010-01-01

    The W3C's Geolocation API may rapidly standardize the transmission of location information on the Web, but, in dealing with such sensitive information, it also raises serious privacy concerns. We analyze the manner and extent to which the current W3C Geolocation API provides mechanisms to support privacy. We propose a privacy framework for the consideration of location information and use it to evaluate the W3C Geolocation API, both the specification and its use in the wild, and recommend s...

  5. Advanced cold rolled steels for automotive applications

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, Harald; Mattissen, Dorothea; Schaumann, Thomas Wilhelm [ThyssenKrupp Steel AG, Center of Materials Excellence, Dortmund (Germany)

    2009-01-15

    Advanced high-strength steels offer a great potential for the further development of automobile bodies-in-white due to their combined mechanical properties of high formability and strength. They represent the first choice in material selection for strength and crash-relevant parts with challenging geometries. The intensive development of multiphase steels by ThyssenKrupp Steel has led to hot dip galvanizing concepts with an outstanding forming potential. Hot rolled, hot dip galvanized complex-phase steels are currently produced in addition to cold rolled dual phase (DP) and retained austenite (RA) or transformation induced plasticity (TRIP) steels. New continuously annealed grades of steel are being developed with tensile strength levels of up to 1000 MPa in combination with sufficient ductility for the high demands of structural automobile components. These steels make use of the classic advantages of microalloying as well as the principles of DP steels and RA / TRIP steels. Further improvement of properties will be reached by the new class of high manganese alloyed steels. (orig.)

  6. Assessment of nutritional resources quality from honeybees (Apis ...

    African Journals Online (AJOL)

    Several environments were selected, namely a rainforest in. Kisangani ... Keywords: Apis mellifera adansonii, honey, bee bread, quality, nutrition, bee ecology, DRC. INTRODUCTION. Various ...... BKN, Co-Proponent of this work, contributed.

  7. Challenges associated with the honey bee ( Apis Mellifera Adansonii )

    African Journals Online (AJOL)

    Challenges associated with the honey bee ( Apis Mellifera Adansonii ) colonies ... Diseases like American and European foulbrood were absent while ... African Journal of Food, Agriculture, Nutrition and Development, Volume 13 No. 2 April ...

  8. Practical Implementation of 10 Rules for Writing REST APIs

    Directory of Open Access Journals (Sweden)

    Jiri Hradil

    2017-01-01

    Full Text Available This paper shows a practical implementation of “10 Rules for Writing REST APIs introduced in the article” (Hradil, 2016. The application is done in Invoice Home (Wikilane, 2016, an invoicing web application for small business and entrepreneurs available world-wide. The API is implemented in JSON hypermedia format (ECMA International, 2016 and with Ruby on Rails framework (Hansson, 2016. The main purpose of the API is to allow connection of Invoice Home with external systems and offer Invoice Home data in simpler format compared to the current HTML format of the full-stack web application. The paper could be also used as a basic template or pattern for any other implementation of the JSON API in any web-based application.

  9. Pemanfaatan Google Maps Api Untuk Visualisasi Data Base Transceiver Station

    OpenAIRE

    Rani, Septia

    2016-01-01

    This paper discusses the use of the Google Maps API to perform data visualization for Base Transceiver Station (BTS) data. BTS are typically used by telecommunications companies to facilitate wireless communication between communication devices with the network operator. Each BTS has important information such as it’s location, it’s transaction traffic, as well as information about revenue. With the implementation of BTS data visualization using the Google Maps API, key information owned by e...

  10. Safe "cloudification" of large images through picker APIs.

    Science.gov (United States)

    Bremer, Erich; Kurc, Tahsin; Gao, Yi; Saltz, Joel; Almeida, Jonas S

    2016-01-01

    The "Box model" allows users with no particular training in informatics, or access to specialized infrastructure, operate generic cloud computing resources through a temporary URI dereferencing mechanism known as "drop-file-picker API" ("picker API" for sort). This application programming interface (API) was popularized in the web app development community by DropBox, and is now a consumer-facing feature of all major cloud computing platforms such as Box.com, Google Drive and Amazon S3. This reports describes a prototype web service application that uses picker APIs to expose a new, "cloudified", API tailored for image analysis, without compromising the private governance of the data exposed. In order to better understand this cross-platform cloud computing landscape, we first measured the time for both transfer and traversing of large image files generated by whole slide imaging (WSI) in Digital Pathology. The verification that there is extensive interconnectivity between cloud resources let to the development of a prototype software application that exposes an image-traversing REST API to image files stored in any of the consumer-facing "boxes". In summary, an image file can be upload/synchronized into a any cloud resource with a file picker API and the prototype service described here will expose an HTTP REST API that remains within the safety of the user's own governance. The open source prototype is publicly available at sbu-bmi.github.io/imagebox. Availability The accompanying prototype application is made publicly available, fully functional, with open source, at http://sbu-bmi.github.io/imagebox://sbu-bmi.github.io/imagebox. An illustrative webcasted use of this Web App is included with the project codebase at https://github.com/SBU-BMI/imageboxs://github.com/SBU-BMI/imagebox.

  11. Pemanfaatan Google Maps Api Untuk Visualisasi Data Base Transceiver Station

    OpenAIRE

    Rani, Septia

    2016-01-01

    This paper discusses the use of the Google Maps API to perform data visualization for Base Transceiver Station (BTS) data. BTS are typically used by telecommunications companies to facilitate wireless communication between communication devices with the network operator. Each BTS has important information such as it's location, it's transaction traffic, as well as information about revenue. With the implementation of BTS data visualization using the Google Maps API, key information owned by e...

  12. PEMANFAATAN GOOGLE MAPS API UNTUK VISUALISASI DATA BASE TRANSCEIVER STATION

    OpenAIRE

    Rani, Septia

    2016-01-01

    This paper discusses the use of the Google Maps API to perform data visualization for Base Transceiver Station (BTS) data. BTS are typically used by telecommunications companies to facilitate wireless communication between communication devices with the network operator. Each BTS has important information such as it’s location, it’s transaction traffic, as well as information about revenue. With the implementation of BTS data visualization using the Google Maps API, key information owned by e...

  13. DIGITAL TRANSFORMATION : HOW APIS DRIVE BUSINESS MODEL CHANGE AND INNOVATION

    OpenAIRE

    Hellbe, Simon; Leung, Peter

    2015-01-01

    Over the years, information technology has created opportunities to improve and extend businesses and to start conducting business in new ways. With the evolution of IT, all businesses and industries are becoming increasingly digitized. This process, or coevolution, of IT and business coming together is called digital transformation. One of the recent trends in this digital transformation is the use of application programmable interfaces (APIs). APIs are standardized digital communication int...

  14. GIANT API: an application programming interface for functional genomics.

    Science.gov (United States)

    Roberts, Andrew M; Wong, Aaron K; Fisk, Ian; Troyanskaya, Olga G

    2016-07-08

    GIANT API provides biomedical researchers programmatic access to tissue-specific and global networks in humans and model organisms, and associated tools, which includes functional re-prioritization of existing genome-wide association study (GWAS) data. Using tissue-specific interaction networks, researchers are able to predict relationships between genes specific to a tissue or cell lineage, identify the changing roles of genes across tissues and uncover disease-gene associations. Additionally, GIANT API enables computational tools like NetWAS, which leverages tissue-specific networks for re-prioritization of GWAS results. The web services covered by the API include 144 tissue-specific functional gene networks in human, global functional networks for human and six common model organisms and the NetWAS method. GIANT API conforms to the REST architecture, which makes it stateless, cacheable and highly scalable. It can be used by a diverse range of clients including web browsers, command terminals, programming languages and standalone apps for data analysis and visualization. The API is freely available for use at http://giant-api.princeton.edu. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  15. Distribution of Stress in Deformation Zone of Niobium Microalloyed Steel

    Science.gov (United States)

    Jandrlić, Ivan; Rešković, Stoja; Brlić, Tin

    2018-07-01

    Microalloyed steels today represent a significant part of total world production and processing of steel. Although widely used, there are scarce data on the stress distribution in the deformation zone of these steels. Research was carried out on two steel grades, both low-carbon structural steels with the same basic chemical composition, with one of them additionally microalloyed with niobium. Differences in the stress distribution in the deformation zone between two tested steels were continuously observed and measured using the methods of digital image correlation and thermography. It has been found out that niobium microalloyed steel has significantly more complex material flow and stress distribution in the deformation zone when compared to the plain low carbon steel.

  16. Distribution of Stress in Deformation Zone of Niobium Microalloyed Steel

    Science.gov (United States)

    Jandrlić, Ivan; Rešković, Stoja; Brlić, Tin

    2018-03-01

    Microalloyed steels today represent a significant part of total world production and processing of steel. Although widely used, there are scarce data on the stress distribution in the deformation zone of these steels. Research was carried out on two steel grades, both low-carbon structural steels with the same basic chemical composition, with one of them additionally microalloyed with niobium. Differences in the stress distribution in the deformation zone between two tested steels were continuously observed and measured using the methods of digital image correlation and thermography. It has been found out that niobium microalloyed steel has significantly more complex material flow and stress distribution in the deformation zone when compared to the plain low carbon steel.

  17. Identification of Complete Repertoire of Apis florea Odorant Receptors Reveals Complex Orthologous Relationships with Apis mellifera

    Science.gov (United States)

    Karpe, Snehal D.; Jain, Rikesh; Brockmann, Axel; Sowdhamini, Ramanathan

    2016-01-01

    Abstract We developed a computational pipeline for homology based identification of the complete repertoire of olfactory receptor (OR) genes in the Asian honey bee species, Apis florea. Apis florea is phylogenetically the most basal honey bee species and also the most distant sister species to the Western honey bee Apis mellifera, for which all OR genes had been identified before. Using our pipeline, we identified 180 OR genes in A. florea, which is very similar to the number of ORs identified in A. mellifera (177 ORs). Many characteristics of the ORs including gene structure, synteny of tandemly repeated ORs and basic phylogenetic clustering are highly conserved. The composite phylogenetic tree of A. florea and A. mellifera ORs could be divided into 21 clades which are in harmony with the existing Hymenopteran tree. However, we found a few nonorthologous OR relationships between both species as well as independent pseudogenization of ORs suggesting separate evolutionary changes. Particularly, a subgroup of the OR gene clade XI, which had been hypothesized to code cuticular hydrocarbon receptors showed a high number of species-specific ORs. RNAseq analysis detected a total number of 145 OR transcripts in male and 162 in female antennae. Most of the OR genes were highly expressed on the female antennae. However, we detected five distinct male-biased OR genes, out of which three genes (AfOr11, AfOr18, AfOr170P) were shown to be male-biased in A. mellifera, too, thus corroborating a behavioral function in sex-pheromone communication. PMID:27540087

  18. Corrosion of carbon steel welds

    International Nuclear Information System (INIS)

    Daniel, B.

    1988-09-01

    This report assesses the factors which cause preferential attack to occur in carbon steel fusion welds. It was concluded that the main factors were: the inclusion content of the weld metal, the potential of the weld metal being less noble than that of the parent, and the presence of low-temperature transformation products in the heat-affected zone of the weld. These factors should be minimized or eliminated as appropriate so that the corrosion allowances determined for carbon steel waste drums is also adequate for the welds. An experimental/theoretical approach is recommended to evaluate the relative corrosion resistance of welds prepared from BS 4360 grade 43A steel to that of the parent material. (author)

  19. Steel alloys

    International Nuclear Information System (INIS)

    Bloom, E.E.; Stiegler, J.O.; Rowcliffe, A.F.; Leitnaker, J.M.

    1977-01-01

    The invention deals with a fuel element for fast breeder reactors. It consits essentially of a uranium oxide, nitride, or carbide or a mixture of these fuels with a plutonium or thorium oxide, nitride, or carbide. The fuel elements are coated with an austenitic stainless steel alloy. Inside the fuel elements, vacancies or small cavities are produced by neutron effects which causes the steel coating to swell. According to the invention, swelling is prevented by a modification of type 304, 316, 321, or 12 K 72HV commercial steels. They consist mainly of Fe, Cr, and Ni in a ratio determined by a temary diagram. They may also contain 1.8 to 2.3% by weight of Mo and a fraction of Si (0.7 to 2% by weight) and Ti(0.10 to 0.5% by weight) to prevent cavity formation. They are structurally modified by cold working. (IHOE) [de

  20. From the TRIP effect and Quenching and Partitioning steels concepts to the development of new high-performance, lean powder metallurgy steels

    International Nuclear Information System (INIS)

    Torralba, José M.; Navarro, Alfonso; Campos, Mónica

    2013-01-01

    A new method of developing lean powder metallurgy steel is proposed. The microstructure of the steel is tailored by combining two different prealloyed steel grades. These materials open a new niche in steel grades for high-performance applications by using a low-cost method of production. Moreover, an alternative route to developing microstructures suitable for manufacturing TRIP and/or Q and P steels is proposed avoiding some of the complex steps that must otherwise be taken to obtain the proper starting microstructure

  1. From the TRIP effect and Quenching and Partitioning steels concepts to the development of new high-performance, lean powder metallurgy steels

    Energy Technology Data Exchange (ETDEWEB)

    Torralba, José M., E-mail: josemanuel.torralba@imdea.org [IMDEA Materials Institute, C/Eric Kandel 2, 28906 - Getafe, Madrid (Spain); Department of Materials Science and Engineering, Universidad Carlos III Av. Universidad, 30, Leganés (Spain); Navarro, Alfonso; Campos, Mónica [Department of Materials Science and Engineering, Universidad Carlos III Av. Universidad, 30, Leganés (Spain)

    2013-06-20

    A new method of developing lean powder metallurgy steel is proposed. The microstructure of the steel is tailored by combining two different prealloyed steel grades. These materials open a new niche in steel grades for high-performance applications by using a low-cost method of production. Moreover, an alternative route to developing microstructures suitable for manufacturing TRIP and/or Q and P steels is proposed avoiding some of the complex steps that must otherwise be taken to obtain the proper starting microstructure.

  2. Honeybee (Apis mellifera ligustica) drone embryo proteomes.

    Science.gov (United States)

    Li, Jianke; Fang, Yu; Zhang, Lan; Begna, Desalegn

    2011-03-01

    Little attention has been paid to the drone honeybee (Apis mellifera ligustica) which is a haploid individual carrying only the set of alleles that it inherits from its mother. Molecular mechanisms underlying drone embryogenesis are poorly understood. This study evaluated protein expression profiles of drone embryogenesis at embryonic ages of 24, 48 and 72h. More than 100 reproducible proteins were analyzed by mass spectrometry on 2D electrophoresis gels. Sixty-two proteins were significantly changed at the selected three experimental age points. Expression of the metabolic energy requirement-related protein peaked at the embryonic age of 48h, whereas development and metabolizing amino acid-related proteins expressed optimally at 72h. Cytoskeleton, protein folding and antioxidant-related proteins were highly expressed at 48 and 72h. Protein networks of the identified proteins were constructed and protein expressions were validated at the transcription level. This first proteomic study of drone embryogenesis in the honeybee may provide geneticists an exact timetable and candidate protein outline for further manipulations of drone stem cells. Crown Copyright © 2010. Published by Elsevier Ltd. All rights reserved.

  3. X-ray diffraction study of slags forming during corrosion resistant steel production

    International Nuclear Information System (INIS)

    Slavov, V.I.; Zadorozhnaya, V.N.; Shurygina, A.V.

    1990-01-01

    Using X-ray diffraction analysis slags, forming during corrosion-resistant 12Kh18N10T grade steel production by two flowsheets, are studied. Standard two-slag technology of steel production does not provide efficient disintegration of chromospinelides in slags, gives high steel contamination with respect to nonmetallic impurities, coarse structure and, as a consequence, presence of macrodefects on rolled products surface. One-slag steel melting technology with titanium alloying of the steel at vacuum causes fast removal of chromospinelides at the beginning of reduction period, promotes titanium absorption by the steel, refines nonmetallic inclusions, provides more fine structure and steel plasticity, removes surface defects

  4. Electron Microscopy Study of Stainless Steel Radiation Damage Due to Long-Term Irradation by Alpha Particles Emitted From Plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Unlu, Kenan [Univ. of Texas, Austin, TX (United States); Rios-Martinez, Carlos [Univ. of Texas, Austin, TX (United States); Saglam, Mehmet [Univ. of Texas, Austin, TX (United States); Hart, Ron R. [Texas A & M Univ., College Station, TX (United States); Shipp, John D. [Texas A & M Univ., College Station, TX (United States); Rennie, John [Texas A & M Univ., College Station, TX (United States)

    1998-04-16

    Radiation damage and associated surface and microstructural changes produced in stainless steel encapsulation by high-fluence alpha particle irradiations from weapons-grade plutonium of 316-stainless steel are being investigated.

  5. Modern high strength QT, TM and duplex-stainless steels

    International Nuclear Information System (INIS)

    Bocquet, P.; Luxenburger, G.; Porter, D.; Ericsson, C.

    2003-01-01

    Pressure vessels are commonly manufactured with normalised steel grades with a yield strength up to 355 MPa or with austenitic stainless steels when corrosion as to be considered. From three decades, modern steels with higher mechanical properties - up to yield strength of 960 Mpa - are available and largely used for other applications where weight saving is of major importance as per off-shore, bridges, cranes, shipbuilding, line pipes.. The paper presents these modern steel's families - TMCP (Thermo Mechanically Controlled Process), QT (Quenched and Tempered) and Duplex (austeno-ferritic) stainless - in comparison with the normalised and austenitic steel grades. The following aspects are presented: the main mechanical properties (tensile and Charpy) as per the requirements of the standards for pressure equipment; some examples of use of these modern steels in the industry are given; the limitations of the forming conditions are considered; the weldability aspects and welds properties are developed; the interest of the PWHT (Post Weld Heat Treatment) is discussed. (orig.)

  6. Inhibiting DNA methylation alters olfactory extinction but not acquisition learning in Apis cerana and Apis mellifera.

    Science.gov (United States)

    Gong, Zhiwen; Wang, Chao; Nieh, James C; Tan, Ken

    2016-07-01

    DNA methylation plays a key role in invertebrate acquisition and extinction memory. Honey bees have excellent olfactory learning, but the role of DNA methylation in memory formation has, to date, only been studied in Apis mellifera. We inhibited DNA methylation by inhibiting DNA methyltransferase (DNMT) with zebularine (zeb) and studied the resulting effects upon olfactory acquisition and extinction memory in two honey bee species, Apis cerana and A. mellifera. We used the proboscis extension reflex (PER) assay to measure memory. We provide the first demonstration that DNA methylation is also important in the olfactory extinction learning of A. cerana. DNMT did not reduce acquisition learning in either species. However, zeb bidirectionally and differentially altered extinction learning in both species. In particular, zeb provided 1h before acquisition learning improved extinction memory retention in A. mellifera, but reduced extinction memory retention in A. cerana. The reasons for these differences are unclear, but provide a basis for future studies to explore species-specific differences in the effects of methylation on memory formation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Novel diagnostic tools for Asian (Apis cerana) and European (Apis mellifera) honey authentication.

    Science.gov (United States)

    Soares, Sónia; Grazina, Liliana; Mafra, Isabel; Costa, Joana; Pinto, M Alice; Duc, Hanh Pham; Oliveira, M Beatriz P P; Amaral, Joana S

    2018-03-01

    Honey can be produced by different species of honeybees, with two being of economic importance due to their use in apiculture, namely Apis mellifera (known as European honeybee) and Apis cerana (known as Asian honeybee). Due to the decline of the wild populations of the Asian honeybee, this honey generally attains much higher market value, being prone to adulteration. This work aims at proposing new tools, based on the use of molecular markers, for the entomological authentication of honey. To this end, new species-specific primers were designed targeting the tRNA leu -cox2 intergenic region and allowing the detection of A. cerana DNA by qualitative polymerase chain reaction (PCR). Additionally, a novel real-time PCR method with high resolution melting analysis was developed to target the 16S rRNA gene of both bee species, allowing their discrimination in different clusters. The proposed methodologies were further applied with success in the authentication of Asian and European honey samples by the identification of honeybee DNA, demonstrating the usefulness of these simple and cost-effective new approaches. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Hegelian Steel

    DEFF Research Database (Denmark)

    Kjær, Poul F.

    2015-01-01

    Even in our globalized world the notion of national economies remain incredibly strong, just as a considerable part of the literature on transnational governance and globalization continue to rely on a zero-sum perspective concerning the relationship between the national and the transnational. De...... of the European steel industry....

  9. Microstructural characterisation and corrosion performance of old railway girder bridge steel and modern weathering structural steel

    International Nuclear Information System (INIS)

    Tewary, N.K.; Kundu, A.; Nandi, R.; Saha, J.K.; Ghosh, S.K.

    2016-01-01

    Highlights: • Microstructure and corrosion performance are compared for two structural steels. • Microstructure evolution shows primarily ferrite-pearlite in both the steels. • Steels show higher corrosion rate in 1% HCl solution than in 3.5% NaCl solution. • The corrosion products show the presence of oxide, hydroxide and oxy-hydroxides. • The corroded surface reveals morphologies like flowery, cotton balls and rosette. - Abstract: A comparison on microstructure and corrosion performance has been made between the two structural steels used in old railway girder bridge (Sample A) and modern grades of weathering structural steel (Sample B). The microstructures, viewed under optical microscope and scanning electron microscope (SEM), show mainly ferrite-pearlite phase constituents in both the steels, A and B. The phase fraction analysis shows higher amount of pearlite in steel A compared to that of steel B. The grain size of steel A is larger than that of steel B under identical processing condition. The immersion corrosion test in 3.5% NaCl shows that the corrosion rate of steel A increases with time, while the same for steel B decreases with time. On the other hand, corrosion test in 1% HCl shows that the corrosion rate of both steel A and B is higher as compared to that of NaCl which always decreases with time. The XRD analysis of corrosion products show the presence of many oxides, hydroxide and oxy-hydroxide like Lepidocrocite (γ-FeOOH), Goethite (α-FeOOH), Akaganeite (β-FeOOH), Magnetite (Fe_3O_4) and Maghemite (γ-Fe_2O_3) in both the steels. The SEM images of corroded surfaces reveal different morphologies like flowery, cotton balls and rosette etc. which indicate that the corrosion products primarily contain Lepidocrocite (γ-FeOOH), Goethite (α-FeOOH) and Akaganeite (β-FeOOH).

  10. Abrasive Wear of Alloyed Cast Steels Applied for Heavy Machinery

    Directory of Open Access Journals (Sweden)

    Studnicki A.

    2015-03-01

    Full Text Available In the paper the results and analysis of abrasive wear studies were shown for two grades of cast steels: low-alloyed cast steel applied for heavy machinery parts such as housing, covers etc. and chromium cast steels applied for kinetic nodes of pin-sleeve type. Studies were performed using the modified in Department of Foundry pin-on-disc method.

  11. Ultra-Low Carbon Bainitic Steels for Heavy Plate Applications

    Science.gov (United States)

    1990-12-01

    these steels. The CCT diagrams 7 of steels typical of the HY grades indicate that the nose of the proeutectoid ferrite/pearlite reactions is located...austenite, carbides, and martensite. An example of the type of CCT diagram for one of the steels used in this investigation is presented in Figure 12...introduce a "bay" of unstable austenite which acts to separate the ferrite "nose" from the bainite/martensite regions on TTT or CCT diagrams , see Figure

  12. BEHAVIOR OF STEEL DP 600 UNDER DYNAMIC CONDITIONS

    Directory of Open Access Journals (Sweden)

    Miroslav Német

    2014-01-01

    Full Text Available Normal 0 21 false false false MicrosoftInternetExplorer4 Dynamic tensile testing of sheet steels is becoming more important. Experimental dynamic tensile technique is depending on the strain rate. For experiments was used two testing method servo hydraulic and single bar method. Experiments was realized on steel grade DP 600. Steel were performed and evaluated static and dynamic tests. Was investigated substructure in static and dynamic loading conditions.

  13. A quick guide to API 510 certified pressure vessel inspector syllabus example questions and worked answers

    CERN Document Server

    Matthews, Clifford

    2010-01-01

    The API Individual Certification Programs (ICPs) are well established worldwide in the oil, gas, and petroleum industries. This Quick Guide is unique in providing simple, accessible and well-structured guidance for anyone studying the API 510 Certified Pressure Vessel Inspector syllabus by summarizing and helping them through the syllabus and providing multiple example questions and worked answers.Technical standards are referenced from the API 'body of knowledge' for the examination, i.e. API 510 Pressure vessel inspection, alteration, rerating; API 572 Pressure vessel inspection; API

  14. CORROSION LOCALISEE DES ACIERS API 5L-X52 DE LA LIGNE ASR/MP SOLLICITE EN SOL ALGERIEN

    OpenAIRE

    BENDJEBBOUR, Amina

    2011-01-01

    L'étude porte sur les défaillances par corrosion localisée dans les aciers API de grade X52 de la ligne de pipelines ASR/MP acheminant les produits pétroliers sollicités en sol corrosif après échec des systèmes de protection anticorrosion (AC) à base de liants hydrocarbonés ou encore à base d'un système en multicouche complétée par une protection cathodique.

  15. Texture Control During the Manufacturing of Nonoriented Electrical Steels

    NARCIS (Netherlands)

    Kestens, L.; Jacobs, S.

    2008-01-01

    Methods of modern quantitative texture analysis are applied in order to characterize the crystallographic texture of various non-oriented electrical steel grades in view of their relation with the magnetic properties of the steel sheet. A texture parameter is defined which quantifies the density of

  16. Effect of nanoprecipitates and grain size on the mechanical properties of advanced structural steels

    International Nuclear Information System (INIS)

    Suarez, M.A.; Alvarez-Perez, M.A.; Alvarez-Fregoso, O.; Juarez-Islas, J.A.

    2011-01-01

    Highlights: → The composition of the steel responded positively to the thermomechanical processing. → Yield strength was increased due to micrometric grain size of 2.2 μm. → Mechanical properties were improved due to nanometric precipitates of 5 nm. → Yield strength values of the API steel were improved up to 877.9 MPa. - Abstract: The microstructure and nanometric precipitates present in advanced structured steel have been studied by high resolution transmission electron microscopy equipped with energy dispersion X-ray microanalysis, in order to relate the nanometric precipitates and grain size with the improvement of the yield strength value of the API steel. The microstructure and nanometric precipitates of the advanced steel were obtained by a combination of thermo-mechanical controlled hot rolling and accelerated cooling procedures. The API steel composition consisted of hot rolled Nb-Ti microalloyed with: 0.07C, 1.40Mn, 0.24Si, 0.020Al, 0.009P, 0.001S, 0.05Mo, 0.5Cr, 0.05Nb, 0.25Ni, 0.10Cu, 0.012Ti, 0.05N in wt%. As a result, this hot rolled steel tested at a strain rate of 5 x 10 -3 s -1 showed an improved yield strength from 798 MPa to 878 MPa due to the micrometric grain size of 2.2 μm and to the nanometric precipitates with a size of around 5 nm in the microstructure of the steel studied.

  17. Thermodynamic phase behavior of API/polymer solid dispersions.

    Science.gov (United States)

    Prudic, Anke; Ji, Yuanhui; Sadowski, Gabriele

    2014-07-07

    To improve the bioavailability of poorly soluble active pharmaceutical ingredients (APIs), these materials are often integrated into a polymer matrix that acts as a carrier. The resulting mixture is called a solid dispersion. In this work, the phase behaviors of solid dispersions were investigated as a function of the API as well as of the type and molecular weight of the carrier polymer. Specifically, the solubility of artemisinin and indomethacin was measured in different poly(ethylene glycol)s (PEG 400, PEG 6000, and PEG 35000). The measured solubility data and the solubility of sulfonamides in poly(vinylpyrrolidone) (PVP) K10 and PEG 35000 were modeled using the perturbed-chain statistical associating fluid theory (PC-SAFT). The results show that PC-SAFT predictions are in a good accordance with the experimental data, and PC-SAFT can be used to predict the whole phase diagram of an API/polymer solid dispersion as a function of the kind of API and polymer and of the polymer's molecular weight. This remarkably simplifies the screening process for suitable API/polymer combinations.

  18. A knowledge discovery object model API for Java

    Directory of Open Access Journals (Sweden)

    Jones Steven JM

    2003-10-01

    Full Text Available Abstract Background Biological data resources have become heterogeneous and derive from multiple sources. This introduces challenges in the management and utilization of this data in software development. Although efforts are underway to create a standard format for the transmission and storage of biological data, this objective has yet to be fully realized. Results This work describes an application programming interface (API that provides a framework for developing an effective biological knowledge ontology for Java-based software projects. The API provides a robust framework for the data acquisition and management needs of an ontology implementation. In addition, the API contains classes to assist in creating GUIs to represent this data visually. Conclusions The Knowledge Discovery Object Model (KDOM API is particularly useful for medium to large applications, or for a number of smaller software projects with common characteristics or objectives. KDOM can be coupled effectively with other biologically relevant APIs and classes. Source code, libraries, documentation and examples are available at http://www.bcgsc.ca/bioinfo/software.

  19. Stainless steel leaches nickel and chromium into foods during cooking.

    Science.gov (United States)

    Kamerud, Kristin L; Hobbie, Kevin A; Anderson, Kim A

    2013-10-02

    Toxicological studies show that oral doses of nickel and chromium can cause cutaneous adverse reactions such as dermatitis. Additional dietary sources, such as leaching from stainless steel cookware during food preparation, are not well characterized. This study examined stainless steel grades, cooking time, repetitive cooking cycles, and multiple types of tomato sauces for their effects on nickel and chromium leaching. Trials included three types of stainless steels and a stainless steel saucepan, cooking times of 2-20 h, 10 consecutive cooking cycles, and four commercial tomato sauces. After a simulated cooking process, samples were analyzed by ICP-MS for Ni and Cr. After 6 h of cooking, Ni and Cr concentrations in tomato sauce increased up to 26- and 7-fold, respectively, depending on the grade of stainless steel. Longer cooking durations resulted in additional increases in metal leaching, where Ni concentrations increased 34-fold and Cr increased approximately 35-fold from sauces cooked without stainless steel. Cooking with new stainless steel resulted in the largest increases. Metal leaching decreases with sequential cooking cycles and stabilized after the sixth cooking cycle, although significant metal contributions to foods were still observed. The tenth cooking cycle resulted in an average of 88 μg of Ni and 86 μg of Cr leached per 126 g serving of tomato sauce. Stainless steel cookware can be an overlooked source of nickel and chromium, where the contribution is dependent on stainless steel grade, cooking time, and cookware usage.

  20. Stainless Steel Leaches Nickel and Chromium into Foods During Cooking

    Science.gov (United States)

    Kamerud, Kristin L.; Hobbie, Kevin A.; Anderson, Kim A.

    2014-01-01

    Toxicological studies show that oral doses of nickel and chromium can cause cutaneous adverse reactions such as dermatitis. Additional dietary sources, such as leaching from stainless steel cookware during food preparation, are not well characterized. This study examined stainless steel grades, cooking time, repetitive cooking cycles, and multiple types of tomato sauces for their effects on nickel and chromium leaching. Trials included three types of stainless steels and a stainless steel saucepan; cooking times of 2 to 20 hours, ten consecutive cooking cycles, and four commercial tomato sauces. After a simulated cooking process, samples were analyzed by ICP-MS for Ni and Cr. After six hours of cooking, Ni and Cr concentrations in tomato sauce increased up to 26- and 7-fold respectively, depending on the grade of stainless steel. Longer cooking durations resulted in additional increases in metal leaching, where Ni concentrations increased 34 fold and Cr increased approximately 35 fold from sauces cooked without stainless steel. Cooking with new stainless steel resulted in the largest increases. Metal leaching decreases with sequential cooking cycles and stabilized after the sixth cooking cycle, though significant metal contributions to foods were still observed. The tenth cooking cycle, resulted in an average of 88 μg of Ni and 86 μg of Cr leached per 126 g serving of tomato sauce. Stainless steel cookware can be an overlooked source of nickel and chromium, where the contribution is dependent on stainless steel grade, cooking time, and cookware usage. PMID:23984718

  1. Using NJOY99 and MCNP4B2 to Estimate the Radiation Damage Displacements per Atom per Second in Steel Within the Boiling Water Reactor Core Shroud and Vessel Wall from Reactor-Grade Mixed-Oxide/Uranium Oxide Fuel for the Nuclear Power Plant at Laguna Verde, Veracruz, Mexico

    International Nuclear Information System (INIS)

    Vickers, Lisa

    2003-01-01

    The government of Mexico has expressed interest in utilizing the Laguna Verde boiling water reactor (BWR) nuclear power plant for the disposition of reprocessed spent uranium oxide (UOX) fuel in the form of reactor-grade mixed-oxide (MOX) fuel. MOX fuel would replace spent UOX fuel as a fraction in the core from 18 to 30% depending on the fuel loading cycle. MOX fuel is expected to increase the neutron fluence, flux, fuel centerline temperature, reactor core pressure, and yield higher energy neutrons.There is concern that a core with a fraction of MOX fuel (i.e., increased 239 Pu wt%) would increase the radiation damage displacements per atom per second (dpa-s -1 ) in steel within the core shroud and vessel wall as compared to only conventional, enriched UOX fuel in the core. The evaluation of radiation damage within the core shroud and vessel wall is a concern because of the potentially adverse affect to personnel and public safety, environment, and operating life of the reactor.The primary uniqueness of this paper is the computation of radiation damage (dpa-s -1 ) using NJOY99-processed cross sections for steel within the core shroud and vessel wall. Specifically, the unique radiation damage results are several orders of magnitude greater than results of previous works. In addition, the conclusion of this paper was that the addition of the maximum fraction of one-third MOX fuel to the LV1 BWR core did significantly increase the radiation damage in steel within the core shroud and vessel wall such that without mitigation of radiation damage by periodic thermal annealing or reduction in operating parameters such as neutron fluence, core temperature, and pressure, it posed a potentially adverse affect to the personnel and public safety, environment, and operating life of the reactor

  2. High strength reinforcing steel bars : concrete shear friction interface : final report : Part A.

    Science.gov (United States)

    2017-03-01

    High-strength steel (HSS) reinforcement, specifically ASTM A706 Grade 80 (550), is now permitted by the AASHTO LRFD Bridge Design Specifications for use in reinforced concrete bridge components in non-seismic regions. Using Grade 80 (550) steel reinf...

  3. Determinación de la tenacidad a la fractura de muestras de Acero 45 fundido, empleando las correlaciones entre el KIC y la energía de impacto medida en el ensayo de Charpy. // Determination of the fracture tenacity of cast Steel grade 45 samples, using th

    Directory of Open Access Journals (Sweden)

    F. Ramos Morales

    2005-05-01

    Full Text Available En el presente trabajo se determinan los valores de tenacidad a la fractura (KIC de muestras de Acero 45 fundido,empleando las correlaciones entre la tenacidad a la fractura y la energía de impacto (CVN obtenida del ensayo de Charpy.Se hace una discusión sobre las correlaciones que más se ajustan en la región de transición y en upper shelf. Se comparanlos valores obtenidos de estas correlaciones a valores de tenacidad a la fractura establecidos en la literatura.Palabras claves: Fractura, energía de impacto, acero fundido.______________________________________________________________________________Abstract.In this paper, the values of fracture toughness (KIC are determined on specimens of cast steel grade 45, using thecorrelations among the fracture toughness (KIC and the impact energy (CVN obtained from a Charpy test. A discussion ismade on the correlations that are better adjusted in the transition region and in upper shelf region. The obtained values arecompared from these correlations to values of fracture toughness (KIC settled down in the literature.Key words. Fracture, impact energy, cast steel.

  4. Forming of High-strength Steels Using a Hot-melt Dry Lubricant

    DEFF Research Database (Denmark)

    Hörnström, Sven-Erik; Karlsson, Erik; Olsson, Mikael

    2008-01-01

    during forming resulting in seizure of the tool/steel sheet contact and extensive scratching of the steel sheet surface. As a result, a number of concepts have been developed in order to reduce the tendency to galling in metal forming, including the development of new dry lubricants, new forming tool...... steel grades and improved surface engineering treatments such as the deposition of low friction CVD and PVD coatings. In the present study the performance of a hot-melt dry lubricant in the forming of hot and cold rolled and hot-dip galvanized high strength steel has been evaluated and compared...... with a conventional rust protection oil using four different tests methods, i.e. a strip reduction test, a bending under tension test, a stretch-forming test and a pin-on disc test. In the tests, two different cold work tool steels, a conventional steel grade and a nitrogen alloyed PM steel grade were evaluated...

  5. APIs for QoS configuration in Software Defined Networks

    DEFF Research Database (Denmark)

    Caba, Cosmin Marius; Soler, José

    2015-01-01

    The OpenFlow (OF) protocol is widely used in Software Defined Networking (SDN) to realize the communication between the controller and forwarding devices. OF allows great flexibility in managing traffic flows. However, OF alone is not enough to build more complex SDN services that require complete...... such as configuration of devices, ports, queues, etc. An Application Programming Interface (API) for dynamic configuration of QoS resources in the network devices is implemented herein, by using the capabilities of OVSDB. Further, the paper demonstrates the possibility to create network services with coarse granularity...... on top of the fine granular services exposed by the QoS configuration API at the SDNC. A series of tests emphasize the capabilities and the performance of the implemented QoS configuration API....

  6. CHARACTERIZATION OF NEW TOOL STEEL FOR ALUMINUM EXTRUSION DIES

    Directory of Open Access Journals (Sweden)

    José Britti Bacalhau

    2014-06-01

    Full Text Available Aluminum extrusion dies are an important segment of application on industrial tools steels, which are manufactured in steels based on AISI H13 steel. The main properties of steels applied to extrusion dies are: wear resistance, impact resistance and tempering resistance. The present work discusses the characteristics of a newly developed hot work steel to be used on aluminum extrusion dies. The effects of Cr and Mo contents with respect to tempering resistance and the Al addition on the nitriding response have been evaluated. From forged steel bars, Charpy impact test and characterization via EPMA have been conducted. The proposed contents of Cr, Mo, and Al have attributed to the new VEX grade a much better tempering resistance than H13, as well as a deeper and harder nitrided layer. Due to the unique characteristics, this new steel provides an interesting alternative to the aluminum extrusion companies to increase their competitiveness.

  7. Safe “cloudification” of large images through picker APIs

    Science.gov (United States)

    Bremer, Erich; Kurc, Tahsin; Gao, Yi; Saltz, Joel; Almeida, Jonas S

    2016-01-01

    The “Box model” allows users with no particular training in informatics, or access to specialized infrastructure, operate generic cloud computing resources through a temporary URI dereferencing mechanism known as “drop-file-picker API” (“picker API” for sort). This application programming interface (API) was popularized in the web app development community by DropBox, and is now a consumer-facing feature of all major cloud computing platforms such as Box.com, Google Drive and Amazon S3. This reports describes a prototype web service application that uses picker APIs to expose a new, “cloudified”, API tailored for image analysis, without compromising the private governance of the data exposed. In order to better understand this cross-platform cloud computing landscape, we first measured the time for both transfer and traversing of large image files generated by whole slide imaging (WSI) in Digital Pathology. The verification that there is extensive interconnectivity between cloud resources let to the development of a prototype software application that exposes an image-traversing REST API to image files stored in any of the consumer-facing “boxes”. In summary, an image file can be upload/synchronized into a any cloud resource with a file picker API and the prototype service described here will expose an HTTP REST API that remains within the safety of the user’s own governance. The open source prototype is publicly available at sbu-bmi.github.io/imagebox. Availability The accompanying prototype application is made publicly available, fully functional, with open source, at http://sbu-bmi.github.io/imagebox://sbu-bmi.github.io/imagebox. An illustrative webcasted use of this Web App is included with the project codebase at https://github.com/SBU-BMI/imageboxs://github.com/SBU-BMI/imagebox. PMID:28269829

  8. Determination of acoustoelastic constant in API-5L-X70 welded pipes; Determinacao da constante acustoelastica de tubos API-5L-X70 com solda

    Energy Technology Data Exchange (ETDEWEB)

    Bittencourt, Marcelo de Siqueira Queiroz; Fonseca, Manoel Antonio da Costa [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Oliveira, Carlos Henrique Francisco de [PETROBRAS S.A., Rio de de Janeiro, RJ (Brazil)

    2008-07-01

    To preserve the environment and avoid financial losses resulting from leaks in the transport of natural oil and gas the industry is particularly concerned to ensure the structural integrity of their pipelines. Grounded pipes may be exposed to damages due to unstable soil movement, and in extreme cases, to failure. Then, techniques to assess stress in pipelines are of central importance. The ultrasonic birefringence technique is an efficient method to measure residual stress. It is based on the changing velocity of the shear wave when it crosses a material under stress; this phenomenon is known as acoustoelasticity. The knowledge of the parameter called acoustoelastic constant is necessary to measure stress using this technique. By the mechanical conformation in the manufacture of welded tubes, from rolled plates, different anisotropy degrees are showed around the cross section of these tubes. In this paper it was studied the acoustoelastic constant for the API-5L-X70 steel pipes, with different thicknesses, diameters and manufacturing processes so as to be able to use this technique to stress measurement in pipelines. (author)

  9. Ultra low carbon bainitic (ULCB) steels after quenching and tempering

    International Nuclear Information System (INIS)

    Lis, A.K.; Lis, J.; Kolan, C.; Jeziorski, L.

    1998-01-01

    The mechanical and Charpy V impact strength properties of new advanced ultra low carbon bainitic (ULBC) steels after water quenching and tempering (WQT) have been investigated. Their chemical compositions are given. The nine continuous cooling transformation diagrams (CCT) of the new ULCB steel grades have been established. The CCT diagrams for ULCB N i steels containing 9% Ni - grade 10N9 and 5% Ni - grade HN5MVNb are given. The comparison between CCT diagrams of 3.5%Ni + 1.5%Cu containing steels grade HSLA 100 and HN3MCu is shown. The effect of the increase in carbon and titanium contents in the chemical composition of ULCB M n steels 04G3Ti, 06G3Ti and 09G3Ti on the kinetics of phase transformations during continuous cooling is presented by the shifting CCT diagrams. The Charpy V impact strength and brittle fracture occurence curves are shown. The effect of tempering temperature on tensile properties of WQT HN3MCu steel is shown and Charpy V impact strength curves after different tempering conditions are shown. The optimum tempering temperatures region of HN3MCu steel for high Charpy V impact toughness at law temperatures - 80 o C(193 K) and -120 o C(153 K) is estimated. The effect of tempering temperature on mechanical properties of HN5MVNb steel is given. The low temperature impact Charpy V toughness of HN5MVNb steel is shown. The optimum range of tempering temperature during 1 hour for high toughness of WQT HN5MVNb steel is given. HN3MCu and HN5MVNb steels after WQT have high yield strength YS≥690 MPa and high Charpy V impact toughness KV≥80 J at -100 o C (173K) and KCV≥50 J/cm 2 at - 120 o C (153K) so they may be used for cryogenic applications

  10. Review of Current Student-Monitoring Techniques used in eLearning-Focused recommender Systems and Learning analytics. The Experience API & LIME model Case Study

    Directory of Open Access Journals (Sweden)

    Alberto Corbi

    2014-09-01

    Full Text Available Recommender systems require input information in order to properly operate and deliver content or behaviour suggestions to end users. eLearning scenarios are no exception. Users are current students and recommendations can be built upon paths (both formal and informal, relationships, behaviours, friends, followers, actions, grades, tutor interaction, etc. A recommender system must somehow retrieve, categorize and work with all these details. There are several ways to do so: from raw and inelegant database access to more curated web APIs or even via HTML scrapping. New server-centric user-action logging and monitoring standard technologies have been presented in past years by several groups, organizations and standard bodies. The Experience API (xAPI, detailed in this article, is one of these. In the first part of this paper we analyse current learner-monitoring techniques as an initialization phase for eLearning recommender systems. We next review standardization efforts in this area; finally, we focus on xAPI and the potential interaction with the LIME model, which will be also summarized below.

  11. Application of Skype API to Control Working Time

    Directory of Open Access Journals (Sweden)

    Julian Vasilev

    2013-11-01

    Full Text Available The purpose of this article is to present an innovative approach to monitor and control working time. A special software program is developed by Delphi implementing Skype API functions. This article shows three different approaches to control working time using the Skype_API program. It automatically detects when an employee goes to his working place and when he leaves work. Moreover it can check periodically weather an employee is at work. The proposed ideas are written for the first time. They may be applied easily in many enterprises with very low costs.

  12. Influencia del precalentamiento en las propiedades de uniones soldadas de acero API 5L-X80 soldadas con alambre tubular autoprotegido

    Directory of Open Access Journals (Sweden)

    Cooper, R.

    2004-08-01

    Full Text Available The present work refers to the characterization of API 5L-X80 pipeline joints welded with self-shielded flux cored wire. This process was evaluated under preheating conditions, with an uniform and steady heat input. All joints were welded in flat position (IG, with the pipe turning and the torch still. Tube dimensions were 762 mm in external diameter and 16 mm in thickness. Welds were applied on single V-groove, with six weld beads, along with three levels of preheating temperatures (room temperature, 100 °C, 160 °C. These temperatures were maintained as interpass temperature. The filler metal E71T8-K6 with mechanical properties different from parent metal was used in undermatched conditions. The weld characterization is presented according to the mechanical test results of tensile strength, hardness and impact test. The mechanical tests were conducted according to API 1104, AWS and ASTM standards. API 1104 and API 51 were used as screening criteria. According to the results obtained, it was possible to remark that it is appropriate to weld API 5L-X80 steel ducts with Self-shielded Flux Cored wires, in conformance to the API standards and no preheat temperature is necessary.

    Este trabajo presenta un estudio sobre la caracterización de las propiedades mecánicas de uniones soldadas con alambre tubular autoprotegido, de acero API 5L-X80. En este sentido, se evalúa la influencia de la temperatura de precalentamiento, manteniendo el aporte de calor uniforme. Todas las uniones soldadas se realizaron en la posición plana (IG, con la antorcha fíja y la tubería girando. Se utilizó un tubo de 762 mm de diámetro exterior y 16 mm de espesor. Las soldaduras se aplicaron sobre una unión de tope con bisel en V simple, utilizando 6 pasadas, con tres niveles de temperatura de precalentamiento (ambiente, 100 °C y 160 °C. Estas temperaturas se mantuvieron como temperatura entre pasadas. El metal de aporte, del tipo E71T8-K6, se utilizó en la

  13. Chemical heat treatment of low alloyed maraging steels

    Energy Technology Data Exchange (ETDEWEB)

    Malinov, L S; Korotich, I K [Zhdanovskij Metallurgicheskij Inst. (Ukrainian SSR)

    1979-09-01

    The investigation concerned the nitriding, cementation, chromizing, borating of economically alloyed maraging grade 04Kh2N5MFYu steel. The investigated methods of chemothermal treatment were found to considerably increase the hardness of the surface layer of the maraging steel. The high tempering of the grade 04Kh2N5MFYu cemented and hardened steel was found to produce secondary hardening. On chromizing, the diffusion layer is an alloyed ferrite which strengthens because of the dispersion hardening on ageing. The formation of the plastic low-carbon martensite at relatively small cooling rates greatly decreases the tendency of the boride layer to cracking.

  14. Nanoprecipitation in bearing steels

    International Nuclear Information System (INIS)

    Barrow, A.T.W.; Rivera-Diaz-del-Castillo, P.E.J.

    2011-01-01

    θ-phase is the main hardening species in bearing steels and appears in both martensitically and bainitically hardened microstructures. This work presents a survey of the microstrucural features accompanying nanoprecipitation in bearing steels. Nanoprecipitate structures formed in 1C-1.5Cr wt.% with additions of Cr, Mn, Mo, Si and Ni are studied. The work is combined with thermodynamic calculations and neural networks to predict the expected matrix composition, and whether this will transform martensitically or bainitically. Martensite tetragonality, composition and the amount of retained austenite are related to hardness and the type of nanoprecipitate structures in martensitic grades. The θ-phase volume fraction, the duration of the bainite to austenite transformation and the amount of retained austenite are related to hardness and a detailed quantitative description of the precipitate nanostructures. Such description includes compositional studies using energy-dispersive spectroscopy, which shows that nanoprecipitate formation takes place under paraequilibrium. Special attention is devoted to a novel two-step bainite tempering process which shows maximum hardness; we prove that this is the most effective process for incorporating solute into the precipitates, which are finer than those resulting from one-step banitic transformation processes.

  15. The development of EUROFER reduced activation steel

    Energy Technology Data Exchange (ETDEWEB)

    Schaaf, B. van der E-mail: vanderschaaf@nrg-nl.com; Tavassoli, F.; Fazio, C.; Rigal, E.; Diegele, E.; Lindau, R.; LeMarois, G

    2003-09-01

    Ferritic martensitic steels show limited swelling and susceptibility to helium effects and can be made with low activation chemical compositions. These properties make them the reference steel for the development of breeding blankets in fusion power plants. EUROFER97 is the European implementation of such a steel, where experience gained from an IEA co-operation with Japan and the US is also implemented. Results obtained so far show that EUROFER steel has attractive mechanical properties even after long ageing times. Compatibility tests in water and PbLi17 are in progress. Oxidised aluminium is the most effective protective layer in PbLi17. The displacement damage and helium formation strongly influence the hydrogen transport in the steel. Present experiments should be backed by tests in a more fusion relevant environment, e.g. IFMIF. The 2.5 dpa neutron irradiations at low temperatures result in a higher DBTT. High dose irradiations, up to 80 dpa, are underway. The early results of ODS grades with EUROFER steel composition show potential of these grades for increasing the operating temperature with 100-150 K.

  16. Laser beam welding of new ultra-high strength and supra-ductile steels

    Science.gov (United States)

    Dahmen, Martin

    2015-03-01

    Ultra-high strength and supra-ductile are entering fields of new applications. Those materials are excellent candidates for modern light-weight construction and functional integration. As ultra-high strength steels the stainless martensitic grade 1.4034 and the bainitic steel UNS 53835 are investigated. For the supra-ductile steels stand two high austenitic steels with 18 and 28 % manganese. As there are no processing windows an approach from the metallurgical base on is required. Adjusting the weld microstructure the Q+P and the QT steels require weld heat treatment. The HSD steel is weldable without. Due to their applications the ultra-high strength steels are welded in as-rolled and strengthened condition. Also the reaction of the weld on hot stamping is reflected for the martensitic grades. The supra-ductile steels are welded as solution annealed and work hardened by 50%. The results show the general suitability for laser beam welding.

  17. Study of the failure in service of a linepipe, helicoidally welded, quality API SL GrB wich conveyed natural gas. Estudio del fallo en servicio de una tuberia soldada helicoidalmente de calidad API SL SrB que transportaba gas natural

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez de Saiz-Solabarria, S.; Elices, M.A. (Departamento de Ciencias de los Materiales e Ingenieria Metalurgica, Universidad del Pais Vasco, Bilbao (Spain))

    1994-01-01

    The possible causes are studied which have incidentally provoked a failure in service on a natural gas linepipe run. This pipe has been manufactured with 6 mm-thick-plate-coil helicoidally welded to 273 mm external diameter. The quality of the material is up to standard API 5L for Grade B and an automatic-helicoidally welding procedure has been with simultaneous inflow at both internal and and external surfaces. The failure appears together with deformations and fracture. (Author)

  18. a five year review of api20e bacteria identification system's

    African Journals Online (AJOL)

    The API20E system (API; bioMérieux, France) is a plastic strip with microtubes containing dehydrated substrates, originally designed for the identification of Enterobacteriaceae so that identification of fermenters with the system would be straightforward. The API20E system was extended to include non- fermenters by the ...

  19. A method for designing fiberglass sucker-rod strings with API RP 11L

    International Nuclear Information System (INIS)

    Jennings, J.W.; Laine, R.E.

    1991-01-01

    This paper presents a method for using the API recommended practice for the design of sucker-rod pumping systems with fiberglass composite rod strings. The API method is useful for obtaining quick, approximate, preliminary design calculations. Equations for calculating all the composite material factors needed in the API calculations are given

  20. Predominant Api m 10 sensitization as risk factor for treatment failure in honey bee venom immunotherapy

    DEFF Research Database (Denmark)

    Frick, Marcel; Fischer, Jörg; Helbing, Arthur

    2016-01-01

    BACKGROUND: Component resolution recently identified distinct sensitization profiles in honey bee venom (HBV) allergy, some of which were dominated by specific IgE to Api m 3 and/or Api m 10, which have been reported to be underrepresented in therapeutic HBV preparations. OBJECTIVE: We performed...... responders and nonresponders regarding levels of IgE sensitization to Api m 1, Api m 2, Api m 3, and Api m 5. In contrast, Api m 10 specific IgE was moderately but significantly increased in nonresponders. Predominant Api m 10 sensitization (>50% of specific IgE to HBV) was the best discriminator...... (specificity, 95%; sensitivity, 25%) with an odds ratio of 8.444 (2.127-33.53; P = .0013) for treatment failure. Some but not all therapeutic HBV preparations displayed a lack of Api m 10, whereas Api m 1 and Api m 3 immunoreactivity was comparable to that of crude HBV. In line with this, significant Api m 10...

  1. On the reaction to deprecation of clients of 4 + 1 popular Java APIs and the JDK

    NARCIS (Netherlands)

    Sawant, A.A.; Robbes, Romain; Bacchelli, A.

    2017-01-01

    Application Programming Interfaces (APIs) are a tremendous resource—that is, when they are stable. Several studies have shown that this is unfortunately not the case. Of those, a large-scale study of API changes in the Pharo Smalltalk ecosystem documented several findings about API deprecations

  2. Resisting majesty: Apis cerana, has lower antennal sensitivity and decreased attraction to queen mandibular pheromone than Apis mellifera

    OpenAIRE

    Shihao Dong; Ping Wen; Qi Zhang; Xinyu Li; Ken Tan; James Nieh

    2017-01-01

    In highly social bees, queen mandibular pheromone (QMP) is vital for colony life. Both Apis cerana (Ac) and Apis mellifera (Am) share an evolutionarily conserved set of QMP compounds: (E)-9-oxodec-2-enoic acid (9-ODA), (E)-9-hydroxydec-2-enoic acid (9-HDA), (E)-10-hydroxy-dec-2-enoic acid (10-HDA), 10-hydroxy-decanoic acid (10-HDAA), and methyl p?hydroxybenzoate (HOB) found at similar levels. However, evidence suggests there may be species-specific sensitivity differences to QMP compounds bec...

  3. Fracture toughness of welded joints of ASTM A543 steel plate

    International Nuclear Information System (INIS)

    Susukida, H.; Uebayashi, T.; Yoshida, K.; Ando, Y.

    1977-01-01

    Fracture toughness and weldability tests have been performed on a high strength steel which is a modification of ASTM A543 Grade B Class 1 steel, with a view to using it for nuclear reactor containment vessels. The results showed that fracture toughness of welded joints of ASTM A543 modified high strength steel is superior and the steel is suitable for manufacturing the containment vessels

  4. Laser beam welding of new ultra-high strength and supra-ductile steels

    OpenAIRE

    Dahmen, M.

    2015-01-01

    Ultra-high strength and supra-ductile are entering fields of new applications. Those materials are excellent candidates for modern light-weight construction and functional integration. As ultra-high strength steels the stainless martensitic grade 1.4034 and the bainitic steel UNS 53835 are investigated. For the supra-ductile steels stand two high austenitic steels with 18 and 28 % manganese. As there are no processing windows an approach from the metallurgical base on is required. Adjusting t...

  5. Evolution of stainless steels in nuclear industry

    International Nuclear Information System (INIS)

    Tavassoli, Farhad

    2010-01-01

    Starting with the stainless steels used in the conventional industry, their adoption and successive evolutions in the nuclear industry, from one generation of nuclear reactors to another, is presented. Specific examples for several steels are given, covering fabrication procedures, qualification methods, property databases and design allowable stresses, to show how the ever-increasing demands for better performance and reliability, in particular under neutron irradiation, have been met. Particular attention is paid to the austenitic stainless steels types 304L, 316L, 316L(N), 316L(N)-IG, titanium stabilized grade 321, precipitation strengthened alloy 800, conventional and low activation ferritic/martensitic steels and their oxygen dispersion strengthening (ODS) derivatives. For each material, the evolution of the associated filler metal and welding techniques are also presented. (author)

  6. A survey of the ethnozoological knowledge of honey bees Apis ...

    African Journals Online (AJOL)

    A survey of the ethnozoological knowledge of honey bee Apis mellifera in Ijebu division of South western Nigeria was carried out to examine the pattern of invasion, control methods of their invasion and their effects in life and economy of the people which also include the medicinal and traditional utilization. The Survey was ...

  7. Effects of honeybee ( Apis mellifera ) pollination on seed set in ...

    African Journals Online (AJOL)

    This study was carried out to determine the efficiency of pollination with honeybee (Apis mellifera) on sunflower hybrid seed production under different types of pollination during 2005 and 2006 in Mustafakemalpasa-Bursa, Turkey. Three pollination types (1) in cages with honeybees, (2) hand pollination (in cages) and (3) in ...

  8. Improving honey production in worker bees (Apis mellifera adansoni ...

    African Journals Online (AJOL)

    Modification of feeding activity, nursing care and undertaker behaviour were carried out among some colonies of honey bees Apis mellifera adansoni L to know the effect on honey production. Apiaries Numbers 1, 2 and 3 contain three replicates of experimental hives while apiary Number 4 contains control hives. All the ...

  9. JASPAR RESTful API: accessing JASPAR data from any programming language.

    Science.gov (United States)

    Khan, Aziz; Mathelier, Anthony

    2018-05-01

    JASPAR is a widely used open-access database of curated, non-redundant transcription factor binding profiles. Currently, data from JASPAR can be retrieved as flat files or by using programming language-specific interfaces. Here, we present a programming language-independent application programming interface (API) to access JASPAR data using the Representational State Transfer (REST) architecture. The REST API enables programmatic access to JASPAR by most programming languages and returns data in eight widely used formats. Several endpoints are available to access the data and an endpoint is available to infer the TF binding profile(s) likely bound by a given DNA binding domain protein sequence. Additionally, it provides an interactive browsable interface for bioinformatics tool developers. This REST API is implemented in Python using the Django REST Framework. It is accessible at http://jaspar.genereg.net/api/ and the source code is freely available at https://bitbucket.org/CBGR/jaspar under GPL v3 license. aziz.khan@ncmm.uio.no or anthony.mathelier@ncmm.uio.no. Supplementary data are available at Bioinformatics online.

  10. Silk formation mechanisms in the larval salivary glands of Apis ...

    Indian Academy of Sciences (India)

    Unknown

    The mechanism of silk formation in Apis mellifera salivary glands, during the 5th instar, was studied. Larval salivary glands were dissected and prepared for light and polarized light microscopy, as well as for scanning and transmission electron microscopy. The results showed that silk formation starts at the middle of the 5th ...

  11. ANALISA PEREKAMAN DATA SUARA DARI SISTEM BLACKBOX PADA KERETA API

    Directory of Open Access Journals (Sweden)

    Emy Setyaningsih

    2016-01-01

    Full Text Available             Makalah ini akan membahas tentang penerapan black box pada kereta api yang diadopsi pertama kali pada pesawat, dengan parameter perekam suara hingga waktu simpan kurang dari 1 hari 8 jam pada media penyimpanan SD Card. Tujuan dari pengujian pada makalah ini adalah membandingkan sumber suara terhadap jarak penerima, sebagai parameter perubahan tingkat suara “dB”. Sistem perekaman suara yang akan ditempatkan pada kereta api ini menggunakan modul rangkaian terintregasi WTR010. Voice record WTR010 merupakan modul rangkaian terintegrasi untuk merekam suara sendiri atau pun suara dari file music / video pada komputer dengan sangat mudah. Modul ini bisa merekam suara sendiri dan langsung di simpan ke dalam format audio. Format audio yang disediakan oleh modul voice record adalah format AD4 dan wav. Hasil pengujian modul black box yang diletakkan pada kereta api, dengan mencoba mengucapkan kata  “SAYA”,  suara dapat terekam pada modul perekam suara yang selanjutnya diolah menggunakan ”software sound editor” yang disimpan pada SD Card ber-ekstensi “wav”. Perbandingan sumber suara terhadap jarak penerima dari pengujian didapatkan sebuah persamaan regresi linier  y = -( 31x – 11  dan R² = 0.972.  Pengujian ini menghasilkan penekanan suara dB dan frekuensi sample Hz yang berbeda.  Kata kunci: black box kereta api, perekaman suara, WTR010

  12. Foraging and pollination behaviour of the African Honey bee ( Apis ...

    African Journals Online (AJOL)

    Foraging and pollination behaviour of the African Honey bee (Apis mellifera adansonii) on Callistemon rigidus flowers in Ngaoundere (Cameroon). F-N Tchuenguem Fohouo, J Messi, D Brüchner, B Bouba, G Mbofung, J Hentchoya Hemo. Abstract. No Abstract Available Journal of the Cameroon Academy of Sciences ...

  13. Effects of Apis mellifera adansonii, L. 1758 (Apidae: Hymenoptera ...

    African Journals Online (AJOL)

    Effects of Apis mellifera adansonii, L. 1758 (Apidae: Hymenoptera) pollination on yields of Cucumeropsis mannii (Naudin) in Kisangani, Democratic Republic of Congo. Boniface Posho Ndola, Yves Brostaux, Guillaume Le Goff, Marie-Lucie Susini, Eric Haubruge, Frederic Francis, Bach Kim Nguyen ...

  14. Standard methods for research on apis mellifera gut symbionts

    Science.gov (United States)

    Gut microbes can play an important role in digestion, disease resistance, and the general health of animals, but little is known about the biology of gut symbionts in Apis mellifera. This paper is part of a series on honey bee research methods, providing protocols for studying gut symbionts. We desc...

  15. Studies on the life cycle and morphometrics of honeybees, Apis ...

    African Journals Online (AJOL)

    The life cycle of the honeybee, Apis mellifera adansonii, was studied in mangrove area by monitoring the developmental stages and morphology of the castes. It was observed that the fate of the eggs were predetermined at the onset leading to drones, queens or workers. It was also established that the three different castes ...

  16. The MPO API: A tool for recording scientific workflows

    Energy Technology Data Exchange (ETDEWEB)

    Wright, John C., E-mail: jcwright@mit.edu [MIT Plasma Science and Fusion Center, Cambridge, MA (United States); Greenwald, Martin; Stillerman, Joshua [MIT Plasma Science and Fusion Center, Cambridge, MA (United States); Abla, Gheni; Chanthavong, Bobby; Flanagan, Sean; Schissel, David; Lee, Xia [General Atomics, San Diego, CA (United States); Romosan, Alex; Shoshani, Arie [Lawrence Berkeley Laboratory, Berkeley, CA (United States)

    2014-05-15

    Highlights: • A description of a new framework and tool for recording scientific workflows, especially those resulting from simulation and analysis. • An explanation of the underlying technologies used to implement this web based tool. • Several examples of using the tool. - Abstract: Data from large-scale experiments and extreme-scale computing is expensive to produce and may be used for high-consequence applications. The Metadata, Provenance and Ontology (MPO) project builds on previous work [M. Greenwald, Fusion Eng. Des. 87 (2012) 2205–2208] and is focused on providing documentation of workflows, data provenance and the ability to data-mine large sets of results. While there are important design and development aspects to the data structures and user interfaces, we concern ourselves in this paper with the application programming interface (API) – the set of functions that interface with the data server. Our approach for the data server is to follow the Representational State Transfer (RESTful) software architecture style for client–server communication. At its core, the API uses the POST and GET methods of the HTTP protocol to transfer workflow information in message bodies to targets specified in the URL to and from the database via a web server. Higher level API calls are built upon this core API. This design facilitates implementation on different platforms and in different languages and is robust to changes in the underlying technologies used. The command line client implementation can communicate with the data server from any machine with HTTP access.

  17. Physical stability of API/polymer-blend amorphous solid dispersions.

    Science.gov (United States)

    Lehmkemper, Kristin; Kyeremateng, Samuel O; Bartels, Mareike; Degenhardt, Matthias; Sadowski, Gabriele

    2018-03-01

    The preparation of amorphous solid dispersions (ASDs) is a well-established strategy for formulating active pharmaceutical ingredients by embedding them in excipients, usually amorphous polymers. Different polymers can be combined for designing ASDs with desired properties like an optimized dissolution behavior. One important criterion for the development of ASD compositions is the physical stability. In this work, the physical stability of API/polymer-blend ASDs was investigated by thermodynamic modeling and stability studies. Amorphous naproxen (NAP) and acetaminophen (APAP) were embedded in blends of hydroxypropyl methylcellulose acetate succinate (HPMCAS) and either poly(vinylpyrrolidone) (PVP) or poly(vinylpyrrolidone-co-vinyl acetate) (PVPVA64). Parameters for modeling the API solubility in the blends and the glass-transition temperature curves of the water-free systems with Perturbed-Chain Statistical Associating Fluid Theory and Kwei equation, respectively, were correlated to experimental data. The phase behavior for standardized storage conditions (0%, 60% and 75% relative humidity (RH)) was predicted and compared to six months-long stability studies. According to modeling and experimental results, the physical stability was reduced with increasing HPMCAS content and increasing RH. This trend was observed for all investigated systems, with both APIs (NAP and APAP) and both polymer blends (PVP/HPMCAS and PVPVA64/HPMCAS). PC-SAFT and the Kwei equation turned out to be suitable tools for modeling and predicting the physical stability of the investigated API/polymer-blends ASDs. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Sperm use economy of honeybee (Apis mellifera) queens

    DEFF Research Database (Denmark)

    Baer, Boris; Collins, Jason; Maalaps, Kristiina

    2016-01-01

    the fecundity and longevity of queens and therefore colony fitness. We quantified the number of sperm that honeybee (Apis mellifera) queens use to fertilize eggs. We examined sperm use in naturally mated queens of different ages and in queens artificially inseminated with different volumes of semen. We found...

  19. Modelling the subgenual organ of the honeybee, Apis mellifera

    DEFF Research Database (Denmark)

    Storm, Jesper; Kilpinen, Ole

    1998-01-01

    In a recent study on the honeybee (Apis mellifera), the subgenual organ was observed moving inside the leg during sinusoidal vibrations of the leg (Kilpinen and Storm 1997). The subgenual organ of the honeybee is suspended in a haemolymph channel in the tibia of each leg. When the leg accelerates...

  20. Biophysics of the subgenual organ of the honeybee, Apis mellifera

    DEFF Research Database (Denmark)

    Kilpinen, Ole; Storm, Jesper

    1997-01-01

    The subgenual organ of the honeybee (Apis mellifera) is suspended in a haemolymph channel in the tibia of each leg. When the leg is accelerated, inertia causes the haemolymph (and the subgenual organ) to lag behind the movement of the rest of the leg. The magnitude of this phase lag determines...

  1. API manager implementation and its use for Indus accelerator control

    International Nuclear Information System (INIS)

    Merh, B.N.; Agrawal, R.K.; Barpande, K.; Fatnani, P.; Navathe, C.P.

    2012-01-01

    The control system software needed for operation of Indus accelerators is coupled to the underlying firmware and hardware of the control system by the Application Programming Interface (API) manager. In the three layered architecture of Indus control system, PVSS-II SCADA is being used at the layer-1(L1) for control and monitoring of various sub-systems. The layer-2(L2) consists of VME bus based system. The API manager plays a crucial role in interfacing the L1 and L2 of the control system. It has to interact with both the PVSS database and the L2. In order to access the PVSS database it uses the PVSS API, a C++ class library, whereas in order to access the L2 custom functions have been built. Several other custom functionalities have also been implemented. The paper presents the important aspects of the API manager like its implementation, its interface mechanism to the lower layer and features like configurability, reusable classes, multithreading capability etc. (author)

  2. Nosema Tolerant Honeybees (Apis mellifera) Escape Parasitic Manipulation of Apoptosis

    DEFF Research Database (Denmark)

    Kurze, Christoph; Le Conte, Yves; Dussaubat, Claudia

    2015-01-01

    conducted three inoculation experiments to investigate in the apoptotic respond during infection with the intracellular gut pathogen Nosema ceranae, which is considered as potential global threat to the honeybee (Apis mellifera) and other bee pollinators, in sensitive and tolerant honeybees. To explore...

  3. The Proteins API: accessing key integrated protein and genome information.

    Science.gov (United States)

    Nightingale, Andrew; Antunes, Ricardo; Alpi, Emanuele; Bursteinas, Borisas; Gonzales, Leonardo; Liu, Wudong; Luo, Jie; Qi, Guoying; Turner, Edd; Martin, Maria

    2017-07-03

    The Proteins API provides searching and programmatic access to protein and associated genomics data such as curated protein sequence positional annotations from UniProtKB, as well as mapped variation and proteomics data from large scale data sources (LSS). Using the coordinates service, researchers are able to retrieve the genomic sequence coordinates for proteins in UniProtKB. This, the LSS genomics and proteomics data for UniProt proteins is programmatically only available through this service. A Swagger UI has been implemented to provide documentation, an interface for users, with little or no programming experience, to 'talk' to the services to quickly and easily formulate queries with the services and obtain dynamically generated source code for popular programming languages, such as Java, Perl, Python and Ruby. Search results are returned as standard JSON, XML or GFF data objects. The Proteins API is a scalable, reliable, fast, easy to use RESTful services that provides a broad protein information resource for users to ask questions based upon their field of expertise and allowing them to gain an integrated overview of protein annotations available to aid their knowledge gain on proteins in biological processes. The Proteins API is available at (http://www.ebi.ac.uk/proteins/api/doc). © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  4. The MPO API: A tool for recording scientific workflows

    International Nuclear Information System (INIS)

    Wright, John C.; Greenwald, Martin; Stillerman, Joshua; Abla, Gheni; Chanthavong, Bobby; Flanagan, Sean; Schissel, David; Lee, Xia; Romosan, Alex; Shoshani, Arie

    2014-01-01

    Highlights: • A description of a new framework and tool for recording scientific workflows, especially those resulting from simulation and analysis. • An explanation of the underlying technologies used to implement this web based tool. • Several examples of using the tool. - Abstract: Data from large-scale experiments and extreme-scale computing is expensive to produce and may be used for high-consequence applications. The Metadata, Provenance and Ontology (MPO) project builds on previous work [M. Greenwald, Fusion Eng. Des. 87 (2012) 2205–2208] and is focused on providing documentation of workflows, data provenance and the ability to data-mine large sets of results. While there are important design and development aspects to the data structures and user interfaces, we concern ourselves in this paper with the application programming interface (API) – the set of functions that interface with the data server. Our approach for the data server is to follow the Representational State Transfer (RESTful) software architecture style for client–server communication. At its core, the API uses the POST and GET methods of the HTTP protocol to transfer workflow information in message bodies to targets specified in the URL to and from the database via a web server. Higher level API calls are built upon this core API. This design facilitates implementation on different platforms and in different languages and is robust to changes in the underlying technologies used. The command line client implementation can communicate with the data server from any machine with HTTP access

  5. Pathogen detection and gut bacteria identification in Apis cerana ...

    African Journals Online (AJOL)

    acer

    other lactic acid bacteria, were isolated from larvae and adult workers, but gave conflicting preliminary identities based on their biochemistry-morphology versus sequence analysis of a partial fragment (1.4 kb) of their 16S rRNA. Key words: Apis cerana indica, bee pathogens, gut bacteria, multiplex polymerase chain ...

  6. Effects of Apis mellifera adansonii, L. 1758 (Apidae: Hymenoptera ...

    African Journals Online (AJOL)

    pollination on yields of Cucumeropsis mannii (Naudin) in Kisangani, ... 1Unit of Functional and Evolutionary Entomology, University of Liège, ... number of fruits per plant, average weight of seeds extracted per fruit, ... enhance symbiotic interactions Apis mellifera with C. mannii in DRC. ..... Trends in Ecology and Evolution,.

  7. Silk formation mechanisms in the larval salivary glands of Apis ...

    Indian Academy of Sciences (India)

    Unknown

    The mechanism of silk formation in Apis mellifera salivary glands, during the 5th instar, was studied. Larval salivary glands .... be used in the silk-manufacture industry. This paper analyses .... (figure 3C); and are highly birefringent (figure 3D).

  8. Pathogen detection and gut bacteria identification in Apis cerana ...

    African Journals Online (AJOL)

    A total of 50 colonies of Apis cerana were sampled in Samut Songkhram (five colonies) and Chumphon (45 colonies) provinces in the central and the south of Thailand, respectively. Diagnostic multiplex polymerase chain reaction (PCR) revealed that 20, 6, 4, 20 and 0% of the samples were infected by Paenibacillus larvae, ...

  9. Automated Steel Cleanliness Analysis Tool (ASCAT)

    Energy Technology Data Exchange (ETDEWEB)

    Gary Casuccio (RJ Lee Group); Michael Potter (RJ Lee Group); Fred Schwerer (RJ Lee Group); Dr. Richard J. Fruehan (Carnegie Mellon University); Dr. Scott Story (US Steel)

    2005-12-30

    The objective of this study was to develop the Automated Steel Cleanliness Analysis Tool (ASCATTM) to permit steelmakers to evaluate the quality of the steel through the analysis of individual inclusions. By characterizing individual inclusions, determinations can be made as to the cleanliness of the steel. Understanding the complicating effects of inclusions in the steelmaking process and on the resulting properties of steel allows the steel producer to increase throughput, better control the process, reduce remelts, and improve the quality of the product. The ASCAT (Figure 1) is a steel-smart inclusion analysis tool developed around a customized next-generation computer controlled scanning electron microscopy (NG-CCSEM) hardware platform that permits acquisition of inclusion size and composition data at a rate never before possible in SEM-based instruments. With built-in customized ''intelligent'' software, the inclusion data is automatically sorted into clusters representing different inclusion types to define the characteristics of a particular heat (Figure 2). The ASCAT represents an innovative new tool for the collection of statistically meaningful data on inclusions, and provides a means of understanding the complicated effects of inclusions in the steel making process and on the resulting properties of steel. Research conducted by RJLG with AISI (American Iron and Steel Institute) and SMA (Steel Manufactures of America) members indicates that the ASCAT has application in high-grade bar, sheet, plate, tin products, pipes, SBQ, tire cord, welding rod, and specialty steels and alloys where control of inclusions, whether natural or engineered, are crucial to their specification for a given end-use. Example applications include castability of calcium treated steel; interstitial free (IF) degasser grade slag conditioning practice; tundish clogging and erosion minimization; degasser circulation and optimization; quality assessment/steel

  10. Automated Steel Cleanliness Analysis Tool (ASCAT)

    International Nuclear Information System (INIS)

    Gary Casuccio; Michael Potter; Fred Schwerer; Richard J. Fruehan; Dr. Scott Story

    2005-01-01

    The objective of this study was to develop the Automated Steel Cleanliness Analysis Tool (ASCATTM) to permit steelmakers to evaluate the quality of the steel through the analysis of individual inclusions. By characterizing individual inclusions, determinations can be made as to the cleanliness of the steel. Understanding the complicating effects of inclusions in the steelmaking process and on the resulting properties of steel allows the steel producer to increase throughput, better control the process, reduce remelts, and improve the quality of the product. The ASCAT (Figure 1) is a steel-smart inclusion analysis tool developed around a customized next-generation computer controlled scanning electron microscopy (NG-CCSEM) hardware platform that permits acquisition of inclusion size and composition data at a rate never before possible in SEM-based instruments. With built-in customized ''intelligent'' software, the inclusion data is automatically sorted into clusters representing different inclusion types to define the characteristics of a particular heat (Figure 2). The ASCAT represents an innovative new tool for the collection of statistically meaningful data on inclusions, and provides a means of understanding the complicated effects of inclusions in the steel making process and on the resulting properties of steel. Research conducted by RJLG with AISI (American Iron and Steel Institute) and SMA (Steel Manufactures of America) members indicates that the ASCAT has application in high-grade bar, sheet, plate, tin products, pipes, SBQ, tire cord, welding rod, and specialty steels and alloys where control of inclusions, whether natural or engineered, are crucial to their specification for a given end-use. Example applications include castability of calcium treated steel; interstitial free (IF) degasser grade slag conditioning practice; tundish clogging and erosion minimization; degasser circulation and optimization; quality assessment/steel cleanliness; slab, billet

  11. Ductile failure analysis of API X65 pipes with notch-type defects using a local fracture criterion

    International Nuclear Information System (INIS)

    Oh, Chang-Kyun; Kim, Yun-Jae; Baek, Jong-Hyun; Kim, Young-Pyo; Kim, Woo-Sik

    2007-01-01

    A local failure criterion for API X65 steel is applied to predict ductile failure of full-scale API X65 pipes with simulated corrosion and gouge defects under internal pressure. The local failure criterion is the stress-modified fracture strain as a function of the stress triaxiality (defined by the ratio of the hydrostatic stress to the effective stress). Based on detailed finite element (FE) analyses with the proposed local failure criterion, burst pressures of defective pipes are estimated and compared with experimental data. For pipes with simulated corrosion defects, FE analysis with the proposed local fracture criterion indicates that predicted failure takes place after the defective pipes attain maximum loads for all cases, possibly due to the fact that the material has sufficient ductility. For pipes with simulated gouge defects, on the other hand, it is found that predicted failure takes place before global instability, and the predicted burst pressures are in good agreement with experimental data, providing confidence in the present approach

  12. Comparison of API 510 pressure vessels inspection planning with API 581 risk-based inspection planning approaches

    International Nuclear Information System (INIS)

    Shishesaz, Mohammad Reza; Nazarnezhad Bajestani, Mohammad; Hashemi, Seyed Javad; Shekari, Elahe

    2013-01-01

    To ensure mechanical integrity, all pressure vessels shall be inspected at the intervals provided in inspection codes or based on a risk-based inspection (RBI) assessment. The RBI assessment may allow previously established inspection intervals to be extended. This paper describes the methodology, analysis and results of two RBI studies conducted on 293 pressure vessel components in two crude oil distillation units. Based on API RBI methodology in API 581 (2008), risk target concept was used for determining inspection dates. It was shown that when thinning is the major active damage, the RBI recommended intervals are as long as twice the API 510 intervals. This paper summarizes that, as a fundamental step in the risk calculation, RBI has a more defined methodology for evaluating equipment for multiple damage mechanisms and a more defined approach to specify the use of other inspection technologies beyond the traditional visual, ultrasonic, and radiography tests. -- Highlights: • RBI calculated inspection intervals are as long as twice of API 510 inspection code. • Two case studies verified the advantage of RBI in inspection planning. • RBI is a more reliable methodology when evaluating multiple damage mechanisms. • Damage factor calculations can be used for determining RSFa value in FFS assessments

  13. On the estimation of the magnetic easy axis in pipeline steels using magnetic Barkhausen noise

    Energy Technology Data Exchange (ETDEWEB)

    Martínez-Ortiz, P. [Laboratorio de Evaluación No Destructiva Electromagnética (LENDE), ESIME-SEPI, Instituto Politécnico Nacional, UPALM Edif. Z-4 3 Piso, Zacatenco, Mexico D.F. 07738 (Mexico); Pérez-Benitez, J.A., E-mail: benitez_edl@yahoo.es [Laboratorio de Evaluación No Destructiva Electromagnética (LENDE), ESIME-SEPI, Instituto Politécnico Nacional, UPALM Edif. Z-4 3 Piso, Zacatenco, Mexico D.F. 07738 (Mexico); Espina-Hernández, J.H. [Laboratorio de Evaluación No Destructiva Electromagnética (LENDE), ESIME-SEPI, Instituto Politécnico Nacional, UPALM Edif. Z-4 3 Piso, Zacatenco, Mexico D.F. 07738 (Mexico); Caleyo, F.; Hallen, J.M. [Departamento de Ingeniería Metalúrgica, ESIQIE, UPALM Edif. 7, Instituto Politécnico Nacional, Zacatenco, C.P. 07738 México D.F. (Mexico)

    2015-01-15

    A method for determination of the magnetic easy axis of the Roll Magnetic Anisotropy in API-5L steels is proposed. The method is based on the fact that the angular dependence of the energy corresponding to the main peak of the Magnetic Barkhausen signal presents uniaxial anisotropy with its easy axis parallel to the rolling direction, independently of the angular dependence of the magnetocrystalline energy in the materials. The proposal is also justified based on the analysis of the influence of microstructural changes, produced by hot-rolling on the domain wall dynamics. - Highlights: • Propose a method for finding the easy axis of roll magnetic anisotropy. • Study of the causes of multi-axial anisotropy of MBN energy in API-5L steels. • Analyze the causes of the roll magnetic anisotropy.

  14. On the estimation of the magnetic easy axis in pipeline steels using magnetic Barkhausen noise

    International Nuclear Information System (INIS)

    Martínez-Ortiz, P.; Pérez-Benitez, J.A.; Espina-Hernández, J.H.; Caleyo, F.; Hallen, J.M.

    2015-01-01

    A method for determination of the magnetic easy axis of the Roll Magnetic Anisotropy in API-5L steels is proposed. The method is based on the fact that the angular dependence of the energy corresponding to the main peak of the Magnetic Barkhausen signal presents uniaxial anisotropy with its easy axis parallel to the rolling direction, independently of the angular dependence of the magnetocrystalline energy in the materials. The proposal is also justified based on the analysis of the influence of microstructural changes, produced by hot-rolling on the domain wall dynamics. - Highlights: • Propose a method for finding the easy axis of roll magnetic anisotropy. • Study of the causes of multi-axial anisotropy of MBN energy in API-5L steels. • Analyze the causes of the roll magnetic anisotropy

  15. Cross-linking BioThings APIs through JSON-LD to facilitate knowledge exploration.

    Science.gov (United States)

    Xin, Jiwen; Afrasiabi, Cyrus; Lelong, Sebastien; Adesara, Julee; Tsueng, Ginger; Su, Andrew I; Wu, Chunlei

    2018-02-01

    Application Programming Interfaces (APIs) are now widely used to distribute biological data. And many popular biological APIs developed by many different research teams have adopted Javascript Object Notation (JSON) as their primary data format. While usage of a common data format offers significant advantages, that alone is not sufficient for rich integrative queries across APIs. Here, we have implemented JSON for Linking Data (JSON-LD) technology on the BioThings APIs that we have developed, MyGene.info , MyVariant.info and MyChem.info . JSON-LD provides a standard way to add semantic context to the existing JSON data structure, for the purpose of enhancing the interoperability between APIs. We demonstrated several use cases that were facilitated by semantic annotations using JSON-LD, including simpler and more precise query capabilities as well as API cross-linking. We believe that this pattern offers a generalizable solution for interoperability of APIs in the life sciences.

  16. Controlling DC permeability in cast steels

    International Nuclear Information System (INIS)

    Sumner, Aaran; Gerada, Chris; Brown, Neil; Clare, Adam

    2017-01-01

    Annealing (at multiple cooling rates) and quenching (with tempering) was performed on specimens of cast steel of varying composition. The aim was to devise a method for selecting the steel with the highest permeability, from any given range of steels, and then increasing the permeability by heat treatment. Metallographic samples were imaged using optical microscopy to show the effect of the applied heat treatments on the microstructure. Commonly cast steels can have DC permeability altered by the careful selection of a heat treatment. Increases of up to 381% were achieved by annealing using a cooling rate of 6.0 °C/min. Annealing was found to cause the carbon present in the steel to migrate from grain boundaries and from within ferrite crystals into adjacent pearlite crystals. The migration of the carbon resulted in less carbon at grain boundaries and within ferrite crystals reducing the number of pinning sites between magnetic domains. This gives rise to a higher permeability. Quenching then tempering was found to cause the formation of small ferrite crystals with the carbon content of the steel predominately held in the martensitic crystal structures. The results show that with any given range of steel compositions the highest baseline DC permeability will be found with the steel that has the highest iron content and the lowest carbon content. For the samples tested in this paper a cooling rate of 4.5 °C/min resulted in the relative permeability of the sample with the highest baseline permeability, AS4, increasing from 783 to 1479 at 0.5 T. This paper shows how heat treatments commonly applied to hypoeutectoid cast steels, to improve their mechanical performance, can be used to also enhance electromagnetic properties of these alloys. The use of cast steels allows the creation of DC components for electrical machines not possible by the widely used method of stacking of electrical grade sheet steels. - Highlights: • A range of structural steels had their

  17. Controlling DC permeability in cast steels

    Energy Technology Data Exchange (ETDEWEB)

    Sumner, Aaran, E-mail: aaran.sumner@nottingham.ac.uk [University of Nottingham, Nottingham University Park Campus, Nottingham NG7 2RD, England (United Kingdom); Gerada, Chris, E-mail: chris.gerada@nottingham.ac.uk [Electrical Machines, University of Nottingham, Tower Building, Nottingham NG7 2RD, England (United Kingdom); Brown, Neil, E-mail: neil.brown@cummins.com [Advanced Electrical Machines Research and Technology at Cummins Power Generation, Peterborough PE2 6FZ, England (United Kingdom); Clare, Adam, E-mail: adam.clare@nottingham.ac.uk [Advanced Manufacturing, University of Nottingham, University Park Campus, Nottingham NG7 2RD, England (United Kingdom)

    2017-05-01

    Annealing (at multiple cooling rates) and quenching (with tempering) was performed on specimens of cast steel of varying composition. The aim was to devise a method for selecting the steel with the highest permeability, from any given range of steels, and then increasing the permeability by heat treatment. Metallographic samples were imaged using optical microscopy to show the effect of the applied heat treatments on the microstructure. Commonly cast steels can have DC permeability altered by the careful selection of a heat treatment. Increases of up to 381% were achieved by annealing using a cooling rate of 6.0 °C/min. Annealing was found to cause the carbon present in the steel to migrate from grain boundaries and from within ferrite crystals into adjacent pearlite crystals. The migration of the carbon resulted in less carbon at grain boundaries and within ferrite crystals reducing the number of pinning sites between magnetic domains. This gives rise to a higher permeability. Quenching then tempering was found to cause the formation of small ferrite crystals with the carbon content of the steel predominately held in the martensitic crystal structures. The results show that with any given range of steel compositions the highest baseline DC permeability will be found with the steel that has the highest iron content and the lowest carbon content. For the samples tested in this paper a cooling rate of 4.5 °C/min resulted in the relative permeability of the sample with the highest baseline permeability, AS4, increasing from 783 to 1479 at 0.5 T. This paper shows how heat treatments commonly applied to hypoeutectoid cast steels, to improve their mechanical performance, can be used to also enhance electromagnetic properties of these alloys. The use of cast steels allows the creation of DC components for electrical machines not possible by the widely used method of stacking of electrical grade sheet steels. - Highlights: • A range of structural steels had their

  18. Host Specificity in the Honeybee Parasitic Mite, Varroa spp. in Apis mellifera and Apis cerana.

    Directory of Open Access Journals (Sweden)

    Alexis L Beaurepaire

    Full Text Available The ectoparasitic mite Varroa destructor is a major global threat to the Western honeybee Apis mellifera. This mite was originally a parasite of A. cerana in Asia but managed to spill over into colonies of A. mellifera which had been introduced to this continent for honey production. To date, only two almost clonal types of V. destructor from Korea and Japan have been detected in A. mellifera colonies. However, since both A. mellifera and A. cerana colonies are kept in close proximity throughout Asia, not only new spill overs but also spill backs of highly virulent types may be possible, with unpredictable consequences for both honeybee species. We studied the dispersal and hybridisation potential of Varroa from sympatric colonies of the two hosts in Northern Vietnam and the Philippines using mitochondrial and microsatellite DNA markers. We found a very distinct mtDNA haplotype equally invading both A. mellifera and A. cerana in the Philippines. In contrast, we observed a complete reproductive isolation of various Vietnamese Varroa populations in A. mellifera and A. cerana colonies even if kept in the same apiaries. In light of this variance in host specificity, the adaptation of the mite to its hosts seems to have generated much more genetic diversity than previously recognised and the Varroa species complex may include substantial cryptic speciation.

  19. Changes in Alternative Splicing in Apis Mellifera Bees Fed Apis Cerana Royal Jelly

    Directory of Open Access Journals (Sweden)

    Shi Yuan Yuan

    2014-12-01

    Full Text Available The Western honey bee (Apis mellifera is a social insect characterized by caste differentiation in which the queen bee and worker bees display marked differences in morphology, behavior, reproduction, and longevity despite their identical genomes. The main causative factor in caste differentiation is the food fed to queen larvae, termed royal jelly (RJ. Alternative splicing (AS is an important RNA-mediated post-transcriptional process in eukaryotes. Here we report AS changes in A. mellifera after being fed either A. mellifera RJ or A. cerana RJ. The results demonstrated that the RJ type affected 4 types of AS in adult A. mellifera: exon skipping, intron retention, alternative 5’ splice sites, and alternative 3’splice sites. After feeding with A. cerana RJ, AS occurred in many genes in adult A. mellifera that encode proteins involved in development, growth, the tricarboxylic acid cycle, and substance metabolism. This study provides the first evidence that heterospecific RJ can influence the AS of many genes related to honey bee development and growth.

  20. Corrosion resistant steel

    International Nuclear Information System (INIS)

    Zubchenko, A.S.; Borisov, V.P.; Latyshev, V.B.

    1980-01-01

    Corrosion resistant steel for production of sheets and tubes containing C, Mn, Cr, Si, Fe is suggested. It is alloyed with vanadium and cerium for improving tensile properties and ductility. The steel can be melted by a conventional method in electric-arc or induction furnaces. The mentioned steel is intended to be used as a substitute for nickel-bearing austenitic steels

  1. Interpretation of toughness tests performed on A533, grade B steel in the transition regime. Modelling and numerical analysis; Interpretation des essais de tenacite de l`acier A533, grade B dans le domaine de la transition fragile-ductile. Simulation numerique et modelisation

    Energy Technology Data Exchange (ETDEWEB)

    Eripret, C.

    1994-01-01

    Modelling the fracture behaviour of pressure vessel steels is of major importance for related structural integrity assessments. It is essential to understand how the micromechanisms control the transition between ductile and brittle fracture for predicting geometry effects on transition temperature. To meet this goal, a model has been developed at EDF/R and DD in the framework of local approach to fracture. Its experimental validation has been achieved by analysing toughness tests performed by AEA Technology for a pressure vessel steel in the transition regime. This large data base has evidenced the specimen thickness effects on toughness properties of the material, as well as influence of prior ductile crack growth. Predictions of the model have been compared with experiments, which shows that the transition curve K{sub 1C} = f (T) can be drawn from model predictions and compared with the RCCM or ASME design curve. Substantial safety margins have been exhibited. They are greater for thin specimens (10 mm) than for thicker specimens (230 mm). However, the transition curve in the upper transition region is still underestimated by the model (for temperatures higher than RTNDT + 50 deg C). Improvement should be made to account for important plasticity development and significant crack growth. (author). 30 figs., 10 tabs., 12 refs.

  2. Navigation API Route Fuel Saving Opportunity Assessment on Large-Scale Real-World Travel Data for Conventional Vehicles and Hybrid Electric Vehicles: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Lei [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Holden, Jacob [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Gonder, Jeffrey D [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-12-06

    The green routing strategy instructing a vehicle to select a fuel-efficient route benefits the current transportation system with fuel-saving opportunities. This paper introduces a navigation API route fuel-saving evaluation framework for estimating fuel advantages of alternative API routes based on large-scale, real-world travel data for conventional vehicles (CVs) and hybrid electric vehicles (HEVs). The navigation APIs, such Google Directions API, integrate traffic conditions and provide feasible alternative routes for origin-destination pairs. This paper develops two link-based fuel-consumption models stratified by link-level speed, road grade, and functional class (local/non-local), one for CVs and the other for HEVs. The link-based fuel-consumption models are built by assigning travel from a large number of GPS driving traces to the links in TomTom MultiNet as the underlying road network layer and road grade data from a U.S. Geological Survey elevation data set. Fuel consumption on a link is calculated by the proposed fuel consumption model. This paper envisions two kinds of applications: 1) identifying alternate routes that save fuel, and 2) quantifying the potential fuel savings for large amounts of travel. An experiment based on a large-scale California Household Travel Survey GPS trajectory data set is conducted. The fuel consumption and savings of CVs and HEVs are investigated. At the same time, the trade-off between fuel saving and time saving for choosing different routes is also examined for both powertrains.

  3. Identification of different processes in magnetization dynamics of API steels using magnetic Barkhausen noise

    International Nuclear Information System (INIS)

    Pérez-Benítez, J A; Espina-Hernández, J H; Le Man, Tu; Caleyo, F; Hallen, J M

    2015-01-01

    This work presents a method to identify processes in magnetization dynamics using the angular dependence of the magnetic Barkhausen noise. The analysis reveals that three different processes of the magnetization dynamics could be identified using the angular dependence of the magnetic Barkhausen noise energy. The first process is the reversed domain nucleation which is related to the magneto-crystalline energy of the material, and the second and third ones are associated with 180° and 90° domain walls motions, respectively. Additionally, two transition regions were identified and they are located between the regions associated with the aforementioned processes. The causes involving these processes are analyzed and a method for establishing their location in the Barkhausen noise signal with respect to the applied magnetic field intensity is proposed. (paper)

  4. Steel. A handbook for materials research and engineering. Vol. 1. Fundamentals

    Energy Technology Data Exchange (ETDEWEB)

    1992-01-01

    This STEEL Textbook is the outcome of reflections within the Materials Committee of the German Iron and Steel Institute on whether to republish the Manual of Special Steels, the highly commendable work by E. Houdremont. Discussions came to the conclusion, however, that for various reasons it was neither possible nor expedient simply to publish a follow-up edition of the famed Houdremont. To begin with and from today's vantage point, there no longer seemed to be any justification for restricting the work to special steels in the sense of the term as understood by E. Houdremont. The term ''special steel'' has never gained acceptance in official circles or standards. If we replace it by the term ''high-grade steel'', which is nowadays defined in standards, and this would appear permissible with certain qualifications, and if we bear in mind that the boundaries between high-grade steels and non-high-grade steels, the commercial and quality steels, although defined in standards (see part A), nonetheless in terms of engineering parameters are quite blurred, so it would seem only fitting for such as work to cover all the various grades of steel, also in view of the great significance of the non-high-grade steels. Because of the very many different grades of steel, this approach necessarily involves the collaboration of very many experts, in other words it entails a joint effort. Moreover, the vast, barely manageable quantity of literature in this field all of which can hardly be analysed by just one person, inevitably leads to the conclusion that there is a need to produce the new work as a joint effort. (orig.).

  5. Antioxidant, antihyperglycemic, and antidiabetic activity of Apis mellifera bee tea.

    Directory of Open Access Journals (Sweden)

    Janielle da Silva Melo da Cunha

    Full Text Available Diabetes has emerged as one of the largest global epidemics; it is estimated that by 2035, there will be 592 million diabetic people in the world. Brazilian biodiversity and the knowledge of traditional peoples have contributed to the treatment of several diseases, including diabetes. Apis mellifera bee tea is used by indigenous Brazilians to treat diabetes, and this traditional knowledge needs to be recorded and studied.The objective of this study was to record the use and to evaluate the antioxidant, antihyperglycemic, and antidiabetic activity of Apis mellifera bee tea, which is used by the Guarani and Kaiowá indigenous people for the treatment of diabetes. Semi-structured interviews were performed with Guarani and Kaiowá ethnic indigenous people from the State of Mato Grosso do Sul, Brazil, seeking to identify the animal species used for medicinal purposes. For the experimental procedures, tea prepared with macerated Apis mellifera bees was used. In vitro assays were performed to evaluate antioxidant activity; direct free radical scavenging, protection against oxidative hemolysis, lipid peroxidation were evaluated in human erythrocytes and potential in inhibiting the formation of advanced glycation end products (AGEs. In vivo, normoglycemic Swiss male mice treated with Apis mellifera tea (AmT were subjected to the oral glucose tolerance test and compared with control and metformin-treated groups. Diet-induced diabetic mice were treated for 21 days with AmT and evaluated for glycemia and malondialdehyde levels in the blood, liver, nervous system, and eyes. During interviews, the indigenous people described the use of Apis mellifera bee tea for the treatment of diabetes. In in vitro assays, AmT showed direct antioxidant activity and reduced oxidative hemolysis and malondialdehyde generation in human erythrocytes. The AmT inhibited the formation of AGEs by albumin-fructose pathways and methylglyoxal products. In vivo, after oral glucose

  6. Antioxidant activity and irritation property of venoms from Apis species.

    Science.gov (United States)

    Somwongin, Suvimol; Chantawannakul, Panuwan; Chaiyana, Wantida

    2018-04-01

    Pharmacological effects of bee venom has been reported, however, it has been restricted to the bee venom collected from European honey bee (Apis mellifera). The aim of the present study was to compare the antioxidant activities and irritation properties of venoms collected from four different Apis species in Thailand, which includes Apis cerena (Asian cavity nesting honeybee), Apis florea (dwarf honeybee), Apis dorsata (giant honeybee), and A. mellifera. Melittin content of each bee venom extracts was investigated by using high-performance liquid chromatography. Ferric reducing antioxidant power, 2, 2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid), and 1, 1-diphenyl-2-picrylhydrazyl assay were used to determine the antioxidant activity, whereas, hen's egg test chorioallantoic membrane assay was used to determine the irritation property of each bee venom extracts. Melittin was the major constituent in all bee venom extracts. The melittin content in A. dorsata, A. mellifera, A. florea, and A. cerena were 95.8 ± 3.2%, 76.5 ± 1.9%, 66.3 ± 8.6%, and 56.8 ± 1.8%, respectively. Bee venom extract from A. dorsata possessed the highest antioxidant activity with the inhibition of 41.1 ± 2.2% against DPPH, Trolox equivalent antioxidant capacity of 10.21 ± 0.74 mM Trolox/mg and equivalent concentration (EC 1 ) of 0.35 ± 0.02 mM FeSO 4 /mg. Bee venom extract from A. mellifera exhibited the highest irritation, followed by A. cerena, A. dorsata, and A. florea, respectively. Melittin was the compound responsible for the irritation property of bee venom extracts since it could induce severe irritation (irritation score was 13.7 ± 0.5, at the concentration of 2 mg/ml). The extract from A. dorsata which possessed the highest antioxidant activity showed no irritation up to the concentration of 0.1 mg/ml. Therefore, bee venom extract from A. dorsata at the concentration not more than 0.1 mg/ml would be suggested for using

  7. Antioxidant, antihyperglycemic, and antidiabetic activity of Apis mellifera bee tea.

    Science.gov (United States)

    Melo da Cunha, Janielle da Silva; Alfredo, Tamaeh Monteiro; Dos Santos, Jéssica Maurino; Alves Junior, Valter Vieira; Rabelo, Luiza Antas; Lima, Emerson Silva; Boleti, Ana Paula de Araújo; Carollo, Carlos Alexandre; Dos Santos, Edson Lucas; de Picoli Souza, Kely

    2018-01-01

    Diabetes has emerged as one of the largest global epidemics; it is estimated that by 2035, there will be 592 million diabetic people in the world. Brazilian biodiversity and the knowledge of traditional peoples have contributed to the treatment of several diseases, including diabetes. Apis mellifera bee tea is used by indigenous Brazilians to treat diabetes, and this traditional knowledge needs to be recorded and studied.The objective of this study was to record the use and to evaluate the antioxidant, antihyperglycemic, and antidiabetic activity of Apis mellifera bee tea, which is used by the Guarani and Kaiowá indigenous people for the treatment of diabetes. Semi-structured interviews were performed with Guarani and Kaiowá ethnic indigenous people from the State of Mato Grosso do Sul, Brazil, seeking to identify the animal species used for medicinal purposes. For the experimental procedures, tea prepared with macerated Apis mellifera bees was used. In vitro assays were performed to evaluate antioxidant activity; direct free radical scavenging, protection against oxidative hemolysis, lipid peroxidation were evaluated in human erythrocytes and potential in inhibiting the formation of advanced glycation end products (AGEs). In vivo, normoglycemic Swiss male mice treated with Apis mellifera tea (AmT) were subjected to the oral glucose tolerance test and compared with control and metformin-treated groups. Diet-induced diabetic mice were treated for 21 days with AmT and evaluated for glycemia and malondialdehyde levels in the blood, liver, nervous system, and eyes. During interviews, the indigenous people described the use of Apis mellifera bee tea for the treatment of diabetes. In in vitro assays, AmT showed direct antioxidant activity and reduced oxidative hemolysis and malondialdehyde generation in human erythrocytes. The AmT inhibited the formation of AGEs by albumin-fructose pathways and methylglyoxal products. In vivo, after oral glucose overload, normoglycemic

  8. Fatigue behaviour of friction welded medium carbon steel and austenitic stainless steel dissimilar joints

    International Nuclear Information System (INIS)

    Paventhan, R.; Lakshminarayanan, P.R.; Balasubramanian, V.

    2011-01-01

    Research highlights: → Fusion welding of dissimilar metals is a problem due to difference in properties. → Solid state welding process such as friction welding is a solution for the above problem. → Fatigue life of friction welded carbon steel and stainless steel joints are evaluated. → Effect of notch on the fatigue life of friction welded dissimilar joints is reported. → Formation of intermetallic is responsible for reduction in fatigue life of dissimilar joints. -- Abstract: This paper reports the fatigue behaviour of friction welded medium carbon steel-austenitic stainless steel (MCS-ASS) dissimilar joints. Commercial grade medium carbon steel rods of 12 mm diameter and AISI 304 grade austenitic stainless steel rods of 12 mm diameter were used to fabricate the joints. A constant speed, continuous drive friction welding machine was used to fabricate the joints. Fatigue life of the joints was evaluated conducting the experiments using rotary bending fatigue testing machine (R = -1). Applied stress vs. number of cycles to failure (S-N) curve was plotted for unnotched and notched specimens. Basquin constants, fatigue strength, fatigue notch factor and notch sensitivity factor were evaluated for the dissimilar joints. Fatigue strength of the joints is correlated with microstructure, microhardness and tensile properties of the joints.

  9. Measuring secondary phases in duplex stainless steels

    Science.gov (United States)

    Calliari, I.; Brunelli, K.; Dabalà, M.; Ramous, E.

    2009-01-01

    The use of duplex stainless steels is limited by their susceptibility to the formation of dangerous intermetallic phases resulting in detrimental effects on impact toughness and corrosion resistance. This precipitation and the quantitative determinations of the phases have received considerable attention and different precipitation sequences (σ phase, χ phase, and carbides) have been suggested. This study investigates the phase transformation during continuous cooling and isothermal treatments in commercial duplex stainless steel grades and the effects on alloy properties, and compares the most common techniques of analysis.

  10. Applications of nitrogen-alloyed stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Sundvall, J.; Olsson, J. [Avesta Sheffield AB (Sweden); Holmberg, B. [Avesta Welding AB (Sweden)

    1999-07-01

    A selected number of applications for different types of nitrogen-alloyed stainless steels are described. The applications and grades are based on how nitrogen improves different properties. Conventional austenitic grades of type 304 and 316 can be alloyed with nitrogen to increase the strength and to maintain the austenite stability after cold deformation when exposed to cryogenic temperatures. Such examples are presented. The addition of nitrogen to duplex grades of stainless steel such as 2205 improves the pitting resistance, among other things, and also enables faster reformation of the austenite in the heat affected zone. This means that heavy plate can be welded without pre-heating or post-weld heating. Such applications are covered. Modern highly alloyed austenitic stainless steels almost always contain nitrogen and all reasons for this are covered, i.e. to stabilise the austenite, to increase the strength, and to improve the pitting resistance. The increased strength is the characteristic exemplified the least, since the higher strength of duplex grades is well known, but examples on austenite stability and improved pitting resistance are presented. (orig.)

  11. Infra-Population and -Community Dynamics of the Parasites Nosema apis and Nosema ceranae, and Consequences for Honey Bee (Apis mellifera) Hosts

    Science.gov (United States)

    Williams, Geoffrey R.; Shutler, Dave; Burgher-MacLellan, Karen L.; Rogers, Richard E. L.

    2014-01-01

    Nosema spp. fungal gut parasites are among myriad possible explanations for contemporary increased mortality of western honey bees (Apis mellifera, hereafter honey bee) in many regions of the world. Invasive Nosema ceranae is particularly worrisome because some evidence suggests it has greater virulence than its congener N. apis. N. ceranae appears to have recently switched hosts from Asian honey bees (Apis cerana) and now has a nearly global distribution in honey bees, apparently displacing N. apis. We examined parasite reproduction and effects of N. apis, N. ceranae, and mixed Nosema infections on honey bee hosts in laboratory experiments. Both infection intensity and honey bee mortality were significantly greater for N. ceranae than for N. apis or mixed infections; mixed infection resulted in mortality similar to N. apis parasitism and reduced spore intensity, possibly due to inter-specific competition. This is the first long-term laboratory study to demonstrate lethal consequences of N. apis and N. ceranae and mixed Nosema parasitism in honey bees, and suggests that differences in reproduction and intra-host competition may explain apparent heterogeneous exclusion of the historic parasite by the invasive species. PMID:24987989

  12. Infra-population and -community dynamics of the parasites Nosema apis and Nosema ceranae, and consequences for honey bee (Apis mellifera) hosts.

    Science.gov (United States)

    Williams, Geoffrey R; Shutler, Dave; Burgher-MacLellan, Karen L; Rogers, Richard E L

    2014-01-01

    Nosema spp. fungal gut parasites are among myriad possible explanations for contemporary increased mortality of western honey bees (Apis mellifera, hereafter honey bee) in many regions of the world. Invasive Nosema ceranae is particularly worrisome because some evidence suggests it has greater virulence than its congener N. apis. N. ceranae appears to have recently switched hosts from Asian honey bees (Apis cerana) and now has a nearly global distribution in honey bees, apparently displacing N. apis. We examined parasite reproduction and effects of N. apis, N. ceranae, and mixed Nosema infections on honey bee hosts in laboratory experiments. Both infection intensity and honey bee mortality were significantly greater for N. ceranae than for N. apis or mixed infections; mixed infection resulted in mortality similar to N. apis parasitism and reduced spore intensity, possibly due to inter-specific competition. This is the first long-term laboratory study to demonstrate lethal consequences of N. apis and N. ceranae and mixed Nosema parasitism in honey bees, and suggests that differences in reproduction and intra-host competition may explain apparent heterogeneous exclusion of the historic parasite by the invasive species.

  13. Teachers' Grading Decision Making

    Science.gov (United States)

    Isnawati, Ida; Saukah, Ali

    2017-01-01

    This study investigated teachers' grading decision making, focusing on their beliefs underlying their grading decision making, their grading practices and assessment types, and factors they considered in grading decision making. Two teachers from two junior high schools applying different curriculum policies in grade reporting in Indonesian…

  14. Draft genome sequence of the Algerian bee Apis mellifera intermissa

    Directory of Open Access Journals (Sweden)

    Nizar Jamal Haddad

    2015-06-01

    Full Text Available Apis mellifera intermissa is the native honeybee subspecies of Algeria. A. m. intermissa occurs in Tunisia, Algeria and Morocco, between the Atlas and the Mediterranean and Atlantic coasts. This bee is very important due to its high ability to adapt to great variations in climatic conditions and due to its preferable cleaning behavior. Here we report the draft genome sequence of this honey bee, its Whole Genome Shotgun project has been deposited at DDBJ/EMBL/GenBank under the accession JSUV00000000. The 240-Mb genome is being annotated and analyzed. Comparison with the genome of other Apis mellifera sub-species promises to yield insights into the evolution of adaptations to high temperature and resistance to Varroa parasite infestation.

  15. “Wrapping” X3DOM around Web Audio API

    Directory of Open Access Journals (Sweden)

    Andreas Stamoulias

    2015-12-01

    Full Text Available Spatial sound has a conceptual role in the Web3D environments, due to highly realism scenes that can provide. Lately the efforts are concentrated on the extension of the X3D/ X3DOM through spatial sound attributes. This paper presents a novel method for the introduction of spatial sound components in the X3DOM framework, based on X3D specification and Web Audio API. The proposed method incorporates the introduction of enhanced sound nodes for X3DOM which are derived by the implementation of the X3D standard components, enriched with accessional features of Web Audio API. Moreover, several examples-scenarios developed for the evaluation of our approach. The implemented examples established the achievability of new registered nodes in X3DOM, for spatial sound characteristics in Web3D virtual worlds.

  16. The simulation of CAMAC system based on Windows API

    International Nuclear Information System (INIS)

    Li Lei; Song Yushou; Xi Yinyin; Yan Qiang; Liu Huilan; Li Taosheng

    2012-01-01

    Based on Windows API, a kind of design method to simulate the CAMAC System, which is commonly used in nuclear physics experiments, is developed. Using C++ object-oriented programming, the simulation is carried out in the environment of Visual Studio 2010 and the interfaces, the data-way, the control commands and the modules are simulated with the functions either user-defined or from Windows API. Applying this method, the amplifier plug AMP575A produced by ORTEC is simulated and performance experiments are studied for this simulation module. The results indicate that the simulation module can fulfill the function of pole-zero adjustment, which means this method is competent for the simulation of CAMAC System. Compared with the simulation based on LabVIEW, this way is more flexible and closer to the bottom of the system. All the works above have found a path to making the virtual instrument platform based on CAMAC system. (authors)

  17. Pertukaran Data Antar Database Dengan Menggunakan Teknologi API

    Directory of Open Access Journals (Sweden)

    Ahmad Hanafi

    2017-03-01

    Full Text Available Electronically data interchange between institutions or companies must be supported with appropriate data storage media capacity. MySQL is a database engine that is used to perform data storage in the form of information, where the data can be utilized as needed. MYSQL has the advantage of which is to provide convenience in terms of usage, and able to work on different platforms. System requirements that must be reliable and multitasking capable of making the database not only as a data storage medium, but can also be utilized as a means of data exchange. Dropbox API is the best solution that can be utilized as a technology that supports the database to be able to Exchange data. The combination of the Dropbox API and database can be used as a very cheap solution for small companies to implement data exchange, because it only requires a relatively small Internet connection.

  18. QSPIN: A High Level Java API for Quantum Computing Experimentation

    Science.gov (United States)

    Barth, Tim

    2017-01-01

    QSPIN is a high level Java language API for experimentation in QC models used in the calculation of Ising spin glass ground states and related quadratic unconstrained binary optimization (QUBO) problems. The Java API is intended to facilitate research in advanced QC algorithms such as hybrid quantum-classical solvers, automatic selection of constraint and optimization parameters, and techniques for the correction and mitigation of model and solution errors. QSPIN includes high level solver objects tailored to the D-Wave quantum annealing architecture that implement hybrid quantum-classical algorithms [Booth et al.] for solving large problems on small quantum devices, elimination of variables via roof duality, and classical computing optimization methods such as GPU accelerated simulated annealing and tabu search for comparison. A test suite of documented NP-complete applications ranging from graph coloring, covering, and partitioning to integer programming and scheduling are provided to demonstrate current capabilities.

  19. Uncovering the immune responses of Apis mellifera ligustica larval gut to Ascosphaera apis infection utilizing transcriptome sequencing.

    Science.gov (United States)

    Chen, Dafu; Guo, Rui; Xu, Xijian; Xiong, Cuiling; Liang, Qin; Zheng, Yanzhen; Luo, Qun; Zhang, Zhaonan; Huang, Zhijian; Kumar, Dhiraj; Xi, Weijun; Zou, Xuan; Liu, Min

    2017-07-20

    Honeybees are susceptible to a variety of diseases, including chalkbrood, which is capable of causing huge losses of both the number of bees and colony productivity. This research is designed to characterize the transcriptome profiles of Ascosphaera apis-treated and un-treated larval guts of Apis mellifera ligustica in an attempt to unravel the molecular mechanism underlying the immune responses of western honeybee larval guts to mycosis. In this study, 24, 296 and 2157 genes were observed to be differentially expressed in A. apis-treated Apis mellifera (4-, 5- and 6-day-old) compared with un-treated larval guts. Moreover, the expression patterns of differentially expressed genes (DEGs) were examined via trend analysis, and subsequently, gene ontology analysis and KEGG pathway enrichment analysis were conducted for DEGs involved in up- and down-regulated profiles. Immunity-related pathways were selected for further analysis, and our results demonstrated that a total of 13 and 50 DEGs were annotated in the humoral immune-related and cellular immune-related pathways, respectively. Additionally, we observed that many DEGs up-regulated in treated guts were part of cellular immune pathways, such as the lysosome, ubiquitin mediated proteolysis, and insect hormone biosynthesis pathways and were induced by A. apis invasion. However, more down-regulated DEGs were restrained. Surprisingly, a majority of DEGs within the Toll-like receptor signaling pathway, and the MAPK signaling pathway were up-regulated in treated guts, while all but two genes involved in the NF-κB signaling pathway were down-regulated, which suggested that most genes involved in humoral immune-related pathways were activated in response to the invasive fungal pathogen. This study's findings provide valuable information regarding the investigation of the molecular mechanism of immunity defenses of A. m. ligustica larval guts to infection with A. apis. Furthermore, these studies lay the groundwork for

  20. Student Attitudes Toward Grades and Grading Practices.

    Science.gov (United States)

    Stallings, William M.; Leslie, Elwood K.

    The result of a study designed to assess student attitudes toward grading practices are discussed. Questionnaire responses of 3439 students in three institutions were tabulated. Responses were generally negative toward conventional grading systems. (MS)